Year 1: Design Report - University of Washington

Transcription

Year 1: Design Report
February 28th, 2011
1
Table of Contents
A - Energy Storage System (ESS) Development .................................................................................................... 10
A.1 - Introduction .............................................................................................................................................. 10
A.2 - Project Plan ............................................................................................................................................... 10
A.3 - Modeling and Specifications ..................................................................................................................... 11
A.3.1 - Design Requirements ......................................................................................................................... 11
A.3.2 - Pack Selection .................................................................................................................................... 11
A.3.3 - Peak Current Analysis ......................................................................................................................... 12
A.3.4 - ESS Thermal Control Strategy ............................................................................................................ 12
A.4 - ESS Electrical Schematic............................................................................................................................ 13
A.5 - Safety ........................................................................................................................................................ 14
A.5.1 - Qualifications ..................................................................................................................................... 14
A.5.2 - Lock-out/Tag-out................................................................................................................................ 16
A.5.3 - ESS Failure Modes .............................................................................................................................. 18
A.5.4 - Fusing ................................................................................................................................................. 19
A.5.5 - Clearance and Creepage .................................................................................................................... 19
A.6 - CAD............................................................................................................................................................ 20
A.6.1 - Mounting ............................................................................................................................................ 20
A.6.2 - Crush Zones ........................................................................................................................................ 21
A.6.3 - Venting and Sealing ............................................................................................................................ 22
A.6.4 - Component Layout ............................................................................................................................. 23
A.6.5 - Electrical Routing................................................................................................................................ 24
A.7 - Protection ................................................................................................................................................. 26
A.7.1 - Load Analysis ...................................................................................................................................... 26
A.7.2 - Sealing ................................................................................................................................................ 26
2
A.7.3 - Vibration and Damping ...................................................................................................................... 26
A.8 - Thermal Analysis ....................................................................................................................................... 27
A.8.1 - Concept and Design ........................................................................................................................... 27
A.8.2 - Heat Generation and RMS Power ...................................................................................................... 28
A.8.3 - System Bleed Process ......................................................................................................................... 28
A.8.4 - Cooling Plates ..................................................................................................................................... 28
A.8.5 - Cooling System Load .......................................................................................................................... 30
A.9 - Charger...................................................................................................................................................... 31
A.10 - Electromagnetic Interference (EMI) Compliance ................................................................................... 31
A.11 - Assembly and Serviceability ................................................................................................................... 32
A.11.1 - Safety Precautions and Risk Management ...................................................................................... 32
A.11.2 - De-energize system (Preparing to service or disassemble ESS) ...................................................... 34
A.11.3 - Assembly .......................................................................................................................................... 34
A.11.4 - Disassembly ...................................................................................................................................... 35
A.11.5 - Service .............................................................................................................................................. 36
A.11.6 - Re-Energize System (Preparing to Energize Vehicle) ....................................................................... 36
3
A.12
Item Type
Case and Mounting
Plastic enclosure
Aluminum Tub
Enclosure Screws
Enclosure Nuts
Steel C Channel
Steel C Channel
Battery Modules
Brackets
Bolts
Extra Long Bolts
Spacers
Lock Nuts
Bolts
Lock Nuts
Sealing/Venting
O-ring
Bulkhead Fitting
Elbow
Pressure Relief Valve
1/8" NPT to hose adapter
Rubber hose
Hose clamp
Rubber grommet
Enclosure Gasket
Wiring and Connections
High Voltage Wires
90 Degree Lug
1/0 Wires
Plastic sheet (cable holders
Cable holders
Fasteners
1/0 Double Lugs
Low Voltage Wires
16 gauge
18 gauge
20 gauge
Conduit
Bus Bar Bolts
Bus Bar Lock Washers
Terminal Bolts
Terminal Lock Washers
Current Sense Transducer
Copper Bus Bars
Heat Shrink Kit
HV Pack Connector
LV Voltage Connector
Motor Disconnect
HV Test Connector
HV Test Connector
HV Test connector
-
Bill
Locking Nuts
Locking Nuts
L-Bracket Lugs
Electrical Distribution Module
(EDM)
Bolts
Locking Nuts
Spacer
1/0 Single Lugs
Manual Safety Disconnect
Bolts
Locking Washers
1/0 Single Lugs
Lug Locking Washers
Lug Nuts
Cooling System
Gasket
Cooling Plate
Cooling Plate
Cooling Plate
Cooling Plate
Pump
Heat Exchanger
Tubing
(BOM)
Quantity
Boltaron 4335
Aluminum 5052
316 Stainless Steel
Metric Nylon-Insert Hex Locknuts, Type
316 Stainless Steel
A36 Hot Rolled Steel
1 sheet
2 sheets
38
40
38
50
M8, h=8mm, w=13mm
Pack Enclosure Rim
McMaster
94205A260
$14.88
1 bar
1 bar
7
14
22
6
6
28
28
28
4'
8'
2" {A} x 1" {B} x 0.188" {C}
3" {A} x 1.410" {B} x 0.170" {C}
24
8
2'
30
30
50
3 cm X 15 cm
M10 L=200 mm
M10 L=265 mm
L=approx 63mm
M10
M10 L=25 mm
M10
Trunk Space
Trunk Space
ESS
At each Vertical Battery
Batteries to Brackets
Brackets to Steel Beams
Speedy Metals
Speedy Metals
A123
Metals Depot
McMaster
McMaster
Online Metals
McMaster
McMaster
McMaster
hc2x1x.188-48
hc3x4.1
N/A
P1316
91290A564
91290A567
L2.OD.625ID.495
94920A600
95430A383
94645A220
$13.33
$49.92
Donation
$21.52
$89.52
$29.84
$10.59
$19.53
$14.61
$18.56
McMaster
Sure Marine Service/Brass
Summit Racing Equipment
Gererant
Wholesale Marine
Find It Parts
Wholesale Marine
Chevy-2-Only
McMaster
5240T11
22305x2
HLY-26-69
VRVI-125-B-V-4
033432_10
27304
18-7307
23034
8609K29
ESS Battery Terminals
ESS
McMaster
Champ Cable
McMaster
6926K62
EXRAD-XLE6-1/0X
2898K17
Plastic Sheet
McMaster
Cable Hold Downs
McMaster
A123?
7572K14
90249A225
N/A
$8.82
Donation
ESS
ESS
ESS
ESS
ESS
McMaster
McMaster
McMaster
McMaster
McMaster
McMaster
McMaster
McMaster
LEM
Rotax Metals
69835K764
69835K754
69835K744
8067K111
92000A420
92153A426
92000A420
92153A426
N/A
C101.H02.12x48
$11.55
$9.45
$5.79
$21.50
$10.36
$6.42
$10.36
$6.42
Donation
$225.09
Keep it Clean Wiring
KICHSOR0750
$5.94
ESS
ESS
ESS
ESS
ESS
ESS
A123
A123
A123
Amphenol
Amphenol
Amphenol
N/A
N/A
PBT-GF30
97-3102A-14S-1S
97-3106A-14S-1P
9760-14
Donation
Donation
Donation
Steel
12.9 Alloy Steel
12.9 Alloy Steel
Stainless Tube 304/304L
Serrated-Flange Hex Locknuts
High-Strength Steel—Class 10.9
Aflas
Brass
Butyl Rubber
1
1
1
1
1
1 ft
1
1
1 Sheet
Copper Long Barrel
HV wires
Chemical-Resistant Polypropylene,
1
3m
3
1 Sheet
White Nylon
10
50
Barrels: polyethylene, Screws: nylon 6/6
MagnaLugs NEMA 2 Hole
10
4
100
Break Pressure: 4 psig (but adjustable)
Blue, Stranded, Irradiated Insulation
PVC
Stainless
Type 316 Stainless Steel
Stainless
Copper Sheet
Orange, Tube Size : 3/4", Flat Diameter : 1
3/16", Shrink Diameter : 0.375"''
Tyco
Yazaki
3P Manual Interlock Motor Connector
Box mount receptacle
Straight plug
Protective Cap
25
Size
Location
Supplier
Part #
Cost
1200 mm X 1000 mm X 3.175
36"x48"x0.1"
M8 L=10mm
Trunk Space
Trunk Space
Pack Enclosure Rim
Emco Industrial Plastics
Online Metals
McMaster
4335-2566-.125-HC
S52.1H36x48x.01
93635A305
$142.00
$32.24
1/8"
Bulkhead Fitting
1/8" NPT inner
Side of battery pack
1/8" NPT
Into bulkhead fitting
1/8" NPT,
Into elbow
1/8" NPT
Into pressure relief valve
5/16" inner dia.
Hose Adapter
For 5/16" fuel line (about .56")
Hose
For 5/16" fuel line
Trunk floor
48" x 36"x1/16"
Pack Enclosure Rim
2
12'
14
14
14
14
1
6
25'
25'
25'
25'
50
100
50
100
1
12"x48"
1
2'
OD: 12.70 mm
24"x24"x1/8"
Bundle Size: 1/2", 13/64" dia.
mount hole
L=1/4"
OD: 0.077"
OD: 0.068"
OD: 0.058"
1/2"
M6 L=10 mm
M6 1.5 mm thick
M6 L=10 mm
M6 1.5 mm thick
130mm X 21 mm X 5 mm
1
1
1
1
1
1
1
Self-Sealing 18-8 Stainless Steel
Zinc Yellow-Chromate Plated Grade 8
Steel
Current Sense Module (CSM)
Bolts
Materials
Item Specifics
Battery Control Module (BCM)
Bolts
of
Purchase
Quantity
$2.44
$3.94
$2.18
$0.99
$72.36
$17.20
$15.51
$7.26
ESS
A123
N/A
Donation
5
5/16" L=1"
BCM
McMaster
92205A583
$18.45
5
5/16"
BCM
McMaster
ESS
A123
N/A
Donation
5
1/4" L=3/4"
CSM
McMaster
92205A540
$11.55
5
1/4"
CSM
McMaster
90099A029
$3.32
CSM
A123
N/A
Donation
1
Nylon-Insert Heavy Hex Locknuts, 18-8
Stainless Steel
$6.96
$3.25
2
2
Stainless Steel
18-8 Stainless Steel Unthreaded Spacers
Magnalug 1/0 gauge
Plug assembly, 350 A, MSD
Receptacle assembly, 350 A, MSD
Class 12.9 Alloy Steel
MagnaLug Sight Hole
5
Butyl Rubber
Aluminum Bare Plate 6061 T651
Engineered Machined Products
Everhot
Everhot
4
5
4
2
2
4
4
2
2
2
1
1
5
CSM
A123
N/A
Donation
EDM
McMaster
92205A555
$17.75
1/4"
EDM
McMaster
L=1 3/8"
1/2"
EDM
EDM
ESS
ESS
MSD
MSD
MSD
MSD
MSD
McMaster
Grote Industries Inc
A123
A123
McMaster
McMaster
Quick Cable
McMaster
McMaster
90099A029
92320A914
GRO84-9204
1-2103172-1
1-1587987-1
91290A320
92153A426
8810-005D
92153A426
94150A345
Donation
Donation
$7.87
$6.42
Cooling Exit Ports
Cooling Plates
Cooling Plates
Cooling Plates
Cooling Plates
McMaster
Online Metals
Online Metals
Online Metals
Online Metals
Cummins Northwest
Pex Universe
Pex Universe
8609K29
as14x39x.375
as14x39x.125
as7x17x.375
as7x17x.125
WP29
HX5x12-20
BPR1001
$72.36
$223.86
$70.98
$38.08
$19.04
$194.00
$109.95
$89.95
M6 L=15 mm
M6 1.5 mm thick
1/4"
M6 1.5 mm thick
M6
1 Sheet
1 Sheet
1 Sheet
1 Sheet
1 Sheet
48" x 36"x1/16"
14”x39”x0.375” 14”x39”x0.125”
7”x17”x0.375”
7”x17”x0.125”
~5in Diameter x 5in length
3” x 3” x 8”
1” Diameter
4
$19.00
1/4" L=2 1/2"
100
100
5
100
50
1
100'
97135A220
$3.32
$34.05
$6.42
$9.58
........................................................................................................................................................................... 37
A.13 - High Power Electrical System ................................................................................................................. 39
B - Bibliography ..................................................................................................................................................... 42
C - Appendix .......................................................................................................................................................... 44
C.1 - Component Sourcing................................................................................................................................. 44
C.1.1 - Remy Letter of Support ...................................................................................................................... 44
C.1.2 - Rinehart Motion Systems Letter of Support ...................................................................................... 45
C.1.3 - GKN Letter of Support ........................................................................................................................ 46
C.1.4 - UQM Letter of Support....................................................................................................................... 47
C.2 - Fuel Selection Matrix Assumptions........................................................................................................... 48
C.3 - Proposed Architecture Selection Matrix Assumptions ............................................................................. 49
C.4 - Technical Assumptions for Controller Selection Matrix ........................................................................... 51
C.5 - ESS Design Project Plan ............................................................................................................................. 52
C.6 - ESS Fuse Data ............................................................................................................................................ 53
5
Table of Figures
Figure 1. TTR CD Mode: Low SOC, High Pack Current .......................................................................................... 12
Figure 2. ESS Electrical Schematic ......................................................................................................................... 14
Figure 3. Mounting of the ESS inside the Vehicle Trunk....................................................................................... 20
Figure 4: Internal Pack Layout .............................................................................................................................. 21
Figure 5. Mounting of the Battery Modules ......................................................................................................... 21
Figure 6. The ESS is situated well outside the crush zone .................................................................................... 22
Figure 7. Venting Strategy with Lid Gasket, Detailed Pressure Relief Valve ........................................................ 23
Figure 8. ESS Component Layout .......................................................................................................................... 24
Figure 9. Trimetric View of Electrical Routing ...................................................................................................... 25
Figure 10. Top View of Electrical Routing ............................................................................................................. 25
Figure 11. Heat Exchanger Cooling Loop Schematic............................................................................................. 27
Figure 12. Final Plate Design ................................................................................................................................. 28
Figure 13. Pressure Distribution in Final Plate Design .......................................................................................... 29
Figure 14. Fluid Temperature Distribution in Final Plate Design .......................................................................... 29
Figure 15. Transient Fluid/Plate Temperature ..................................................................................................... 30
Figure 16. BRUSA Charger Specifications.............................................................................................................. 31
Figure 17. EMI Coupling Modes (Electromagnetic Compatibility)........................................................................ 32
Figure 18: Vehicle Level High-Voltage Schematic ................................................................................................. 39
6
Table of Tables
Table 1. Summary of Design Requirements.......................................................................................................... 11
Table 2. 6x15s3p, 7x15s3p Pack Configurations: Summary of Extreme Values ................................................... 12
Table 3. Description of vehicle operation modes and torque distribution in each mode ................................... 13
Table 4. ESS Temperature levels and actions taken for each ............................................................................... 13
Table 5. NFPA 70E Standard Approach Boundaries for Systems 301V to 750V ................................................... 15
Table 6. EPO tests performed by ESS (from A123) ............................................................................................... 18
Table 7. HSV response to fault signals from the BCM .......................................................................................... 18
Table 8. HV and LV Circuit Separation .................................................................................................................. 19
Table 9. Minimum Spacing to prevent Accidental Contact .................................................................................. 20
Table 10. HV Battery Pack Information ................................................................................................................ 33
Table 11. High Power Components ...................................................................................................................... 39
Table 12. Fuse Sizing ............................................................................................................................................. 40
Table 13. Cable gauge selection ........................................................................................................................... 41
Table 14. Bibliography and Appendices Revision Log........................................................................................... 51
7
A. Glossary of Terms
505
505 vehicle drive cycle
ANL
Argonne National Lab
Autonomie
Vehicle modeling program, authored by ANL
AVTC
Advanced vehicle technical competition
B20
Bio-Diesel, with a blend of 80% petroleum, 20% bio-fuel
BAS
Belted assisted starter systems used to assist engine efficiency
CAD
Computer Aided Design
CD
Charge depleting mode of operation
CH4
Methane (a greenhouse gas)
CO
Carbon monoxide
CS
Charge sustaining mode of operation
DC
Direct current
DFMEA
Dynamic fault management effects analysis
DOE
Department of Energy
DP
Dual Polarization (battery model)
DPF
Diesel particulate filter
dSPACE
Hardware provider of HIL systems, and HSV’s.
E85
Petroleum mix with 85% ethanol, 15% petroleum
E10
Petroleum mix with 10% ethanol, 90% petroleum
ECM
Engine control module
EHS
Electrical health and safety
EPO
Emergency Power Off
EREV
Extended range electric vehicle
ESS
Electrical sub-system
FR
Fire resistant
FTA
Fault tree analysis
GHG
Greenhouse gas
GM
General Motors
GREET
Greenhouse gas regulated emissions and energy use in transportation model
GUI
Graphical user interface
GVWR
Gross vehicle weight rating
HC
Hydro-carbon
HEV
Hybrid electric vehicle
HIL
Hardware in the loop
HVIL
High Voltage Interlock Loop
HSV
Hybrid supervisory controller
HPPC
Hybrid pulse power characterization (test)
HV
High voltage
HWFET
Highway fuel economy test
ICE
Internal combustion engine
IEEE
Institute of Electrical and Electronics Engineers
IVM
Initial vehicle movement
kW
Kilowatts
MATLAB
Computational program
MABx
MicroAutoBox
8
MPG
Miles per gallon
MSD
Manual safety disconnect
NOx
Nitrogen oxide emissions
NX
CAD program used for modeling vehicles
PEU
Petroleum energy use
PHEV
Plugin hybrid electric vehicle
PM
Particulate matter
PNGV
Partnership of new generation vehicles (battery model)
PPE
Power protection equipment
PSAT
Powertrain System Analysis Toolkit program, precursor to Autonomie.
PTW
Pump to wheel emissions
RBS
Regenerative braking system
RPM
Rotations per minute
RTM
Rear traction motor
SAE
Society of Automotive Engineers
SOC
State of charge
SEREV
Series extended range electric vehicle
SOP
Standard operating procedure
THS
Toyota hybrid system
TTR
Through the road style, power split hybrid
TTR+BAS
Through the road style, power split hybrid with BAS system added
USO6
Fuel economy drive cycle
UF
Utility factor
UW
University of Washington
WTP
Well to pump emissions
WTW
Well to wheel emissions
9
A - Energy Storage System (ESS) Development
A.1 - Introduction
The University of Washington team selected a seven-module A123 setup, with three parallel cells per module.
The resulting nominal pack voltage is 340 volts. Approximately fifteen battery configurations were compared,
with two primary considerations having the greatest impact on the battery layout: the decision between six or
seven modules, and how batteries were to be oriented in the vehicle.
Including a seventh module forced us to compare many battery layouts, where connection complexity,
installation/removal, space claim, safety, weight, cooling, and EMI were all design constraints. The advantage
of having additional power and range with a seven-module design, over that of a six-module design,
outweighed the various design considerations for packaging the seventh module.
Safety has always been the number one design consideration, which is why we selected a vertical battery
layout with an electrically insulating plastic rim set down below the battery module terminals. Significant
effort was placed on making the battery pack easy to service with accessible and logically positioned wire
routing. We also decided that removing a 500lb battery pack with an engine hoist is potentially more
dangerous than removing individual modules by hand or with the engine hoist.
Our final design incorporates two cooling plates and vertically oriented battery modules. Because A123
recommends in their ICD that the modules should be cooled from their sides, we did not initially consider
cooling the base of the modules, but A123 themselves suggested this option at the winter workshop design
review.
A.2 - Project Plan
One risk area in the ESS project plan is the design and fabrication of the rigid plastic upper enclosure. Because
of this, significant time has been allocated to the design and fabrication procedure. Another risk area is the
fabrication of the module cooling plates because the manufacturing method we selected requires brazing of
the two halves of the plates. If the plates cannot be fabricated by students in our shop, our mitigation plan is
to have the plate fabrication outsourced. A similar mitigation plan would be used for a number of other critical
components including the battery mounting brackets and the enclosure-sealing gasket. The project plan
outline can be found in the ESS Design Project Plan appendix.
Ordering parts for the ESS depends on when the A123 approval is received. Welding the aluminum base
enclosure requires someone familiar with the proper welding techniques, and is a factor critical to the
project’s success. Dependencies outside the immediate scope of the ESS design include the motor subframe
mounting, due to its close proximity to the ESS, and those component mountings that are adjacent to the ESS.
Teams will have to collaborate effectively for design, fabrication, and installation.
A portion of the mechanical team consisting of three members is focused on the thermal management of the
ESS. A second group consisting of electrical and mechanical team members will be working solely on the
battery pack design and will become core members for assembling and servicing the ESS. Two students have
shown interest in fabricating the Acrylic/PVC enclosure lid for both a senior design project and thesis project.
10
A.3 - Modeling and Specifications
A.3.1 - Design Requirements
To define the design requirements of the ESS system, the EcoCAR 2 blended four-cycle was used as a metric of
performance. Table 1 summarizes the design requirements for the ESS. The bound Vmin is the minimum
voltage across the battery terminals; this was chosen so as to avoid the shutdown of the selected DC/DC
converter, which occurs at terminal voltages below 200 V. Safety considerations, as well as the need to
comply with the EcoCAR 2 non-year specific rules, drove the selection of the upper bound of Vmax. The
currents Ipack, rms , Ipack, max , IRTM, rms , IRTM, max are desired to be as low as possible over the EcoCAR 2 four-cycle
while still meeting all power requests from the driver (< 2% trace miss). The desire for low currents is driven
by fuse and cable sizing considerations: lower RMS currents allow lighter, more accommodating, high-voltage
cables. The final design requirement is the energy capacity, which is desired to be as high as possible in order
to achieve the maximum all-electric vehicle range.
Table 1. Summary of Design Requirements
Extreme Value
Unit
Ipack, rms
Low
A
IRTM, rms
Low
A
Ipack, max
Low
A
IRTM, max
Low
A
Vmin
200
V
Vmax
400
V
Capacity
High
kWh
A.3.2 - Pack Selection
Due to cost and support considerations, we are excited to accept A123 Systems offer of a choice of four
different battery pack options (6x15s2p, 6x15s3p, 7x15s2p, and 7x15s3p module configurations). Between the
four options, the team elected only to consider the 3p module packs because they have higher total capacity
and thus can offer greater all-electric vehicle ranges. Both the 6x15s3p and the 7x15s3p module packs were
set up in an identical simulated TTR hybrid vehicle using ANL’s Autonomie plug-and-play hybrid vehicle
modeling environment. The two packs were modeled under a variety of vehicle conditions: CD mode at an
initial SOC of 1, 0.5, and 0.3; and CS mode at an initial SOC of 0.9, 0.5, and 0.3. The initial values of SOC were
selected to sample the battery response over the SOC window of our control strategy (SOC will be controlled
to vary from 0.2 to 1). Prior to modeling the two packs, it was expected that the values for RMS currents and
peak currents would be higher at lower initial SOC’s. Also, the most demanding power requirements were
expected to occur in the US06 City cycle due to the frequent acceleration requests. The results are
summarized below in Table 2.
11
Table 2. 6x15s3p, 7x15s3p Pack Configurations: Summary of Extreme Values
Value
6x15s3p
7x15s3p
Unit
Ipack, rms
138.6
120
A
IRTM, rms
123.6
105.3
A
Ipack, max
507.2
426.5
A
IRTM, max
488.1
410.5
A
Vmin
262.3
311.8
V
Vmax
316.6
368.1
V
Capacity
16.2
18.9
kWh
By inspection of the table, 7x15s3p configuration outperforms the 6x15s3p configuration in terms of both
total capacity and current draw. The values for total battery capacity were given by the battery pack provider
A123. Furthermore, the 7 module configuration is well above the minimum voltage requirement and below
the maximum voltage requirement. In short, the modeling aspect highly encouraged selecting the 7x15s3p
pack configuration. The report 4 CAD section discusses the challenges of physically integrating the 7x15s3p
versus the 6x13s3p in the vehicle.
A.3.3 - Peak Current Analysis
In the previous section, Pack Selection, the most aggressive cycle was identified to be the US06 City cycle. In
simulation, under conditions of low SOC the battery must supply more current to maintain the same
performance as at a high SOC. Analysis of the simulated vehicle’s performance over the US 06 City cycle
determined that a current of 200 A is drawn from the battery pack for a period of roughly ten seconds (see
Figure 1). This detail is particularly important for the determination of fuse sizing, and argues for a cable sized
with an RMS rating of 200 A, rather than just 120 A. Determination of HV cable sizing is explored further in the
section titled: High Power Electrical System.
Figure 1. TTR CD Mode: Low SOC, High Pack Current
A.3.4 - ESS Thermal Control Strategy
In order to protect the ESS system, several key checks within the control strategy were added which
determine the hybrid vehicle’s state of operation. As mentioned previously, the vehicle will operate using two 12
general strategies: CD (charge depleting) or CS (charge sustaining). The individual modes in these strategies
along with their general operation strategy are detailed in Table 3.
Table 3. Description of vehicle operation modes and torque distribution in each mode
EV ONLY
ICE
TORQUE
0
ESS Power
Requirement
+++
ICE-ASSISTED HYBRID
+
++
++
+
+++
0
++++
-
++
BRAKES
TORQUE
++
ESS Power
Requirement
MECHANICAL
BRAKING
---
0
Regen braking disabled, mechanical brakes deliver 100% negative DTR from brake pedal
REGEN BRAKING
-
--
Regen braking enabled, RTM delivers 100% negative DTR up to RTM_Torque_NegativeLimit
Mechanical brakes deliver the remainder
PROPEL MODES
RTM-ASSISTED
HYBRID
ICE ONLY
LOAD-SHIFTING
REGEN
PERFORMANCE
BRAKING MODES
PROPEL MODE DESCRIPTION
CS/CD
RTM handles 100% of Driver Torque Request (DTR)
RTM delivers 100% DTR up to RTM_Torque_PositiveLimit, ICE assists for DTR above
limit
ICE delivers 100% DTR up to ICE_Torque_PositiveLimit, RTM assists for DTR above
limit
ICE handles all 100% of DTR
RTM applies negative torque to load shift the ICE to regen and increase ICE
efficiency
Torque split evenly between RTM and ICE
CD
CD
CS
CS
CS
CD
BRAKING MODE DESCRIPTION
In the case of high coolant temperature conditions, the control strategy modifies the present mode, or
transitions to a new one, in order to decrease the heat generation within the battery. The set of rules
governing the thermal control strategy can be found in Table 4, and is based on the temperature transmitted
by the coolant inlet temperature signal. Two levels of mode-shifting for thermal control exist in an effort to
avoid an Emergency Power Off (EPO) event. The first mode targets a reduced load on the RTM, in an effort to
allow the coolant temperature to stabilize at a more moderate level, while the second mode disables all use of
the RTM until the temperature drops to acceptable levels. The inlet temperature is directly influenced by the
ambient temperature.
Table 4. ESS Temperature levels and actions taken for each
Inlet
Temperature
(°C)
37-40
35-37
> 33
Charge Depleting
Charge Sustaining
Allowed modes:
ICE ONLY
MECHANICAL BRAKING
EV ONLY disabled
PERFORMANCE disabled
PERFORMANCE disabled
REGEN BRAKING – Reduce ‘Torque_Negative_Limit’
REGEN BRAKING - reduce ‘Torque_Negative_Limit’
Maximum coolant flow
Full radiator fans
30-33
Radiator fans and coolant pump active
0-30
No active cooling
<0
Heat coolant
A.4 - ESS Electrical Schematic
A complete electrical schematic of the proposed ESS concept is shown in Figure 2 below.
13
LV MBB (20 AWG)
Copper Bus Bar
Copper Bus Bar
LV Battery
5A FUSE
1/0 AWG
Copper Bus Bar
EDS Rear
18 AWG
Copper Bus Bar
LV MBB (20 AWG)
Copper Bus Bar
Charger Switch
1/0 AWG
CSM
HVIL (18 AWG)
20 AWG
EDS Front
250A
Fuse
HV Connector
MSD
Inertial Switch
1/0 AWG
HVIL
HVIL
LEM
EDM
1/0 AWG
LV Connector
18 AWG
18 AWG
18 AWG
20 AWG
HVIL
3 Wake Signals (20 gauge)
LV MBB (20 AWG)
BCM Ground (16 AWG)
2 Charger Enable Signals
BCM
12 V PWR (16 AWG)
20 AWG
Battery Coolant Temp
20 AWG
Coolant Liquid Level
20 AWG
FGD
15A Mini Fuse
Wires and Bus Bars
Symbols
Low Voltage Wire
High Voltage Cable
Copper Bus Bar
Fuse
Contactor Coil
Contactor
Manual Switch
Kilovac Contactor
Devices
Manuel Service Disconnect
Current Sense Module
Measurement and Balance Board
Battery Control Module
High Voltage Interlock Loop
Flammable Gas Detector
MSD
CSM
EDM
MBB
BCM
HVIL
FGD
Figure 2. ESS Electrical Schematic
A.5 - Safety
As previously mentioned, safety has always been the number one design consideration for our ESS concept.
Along with design choices made to emphasize safety, procedural and operational safety are also a huge
concern to our team.
A.5.1 - Qualifications
To service the ESS, team members must annually complete the Environmental Health and Safety Lockout/Tag-out Safety Training at UW, be CPR/First Aid/AED certified, and be approved by one of the team leads.
The University of Washington offers free CPR certification and First Aid/AED training through EH&S for the
campus. It is prohibited to work alone, or to service the ESS without required personal protective equipment
and following lock-out/tag-out procedures.
During the lock-out/tag-out training, electrical safety when working with high voltage components will also be
addressed, including:



safety practices and procedural requirements for the ESS;
the relationship between electrical hazards and possible injury;
recognizing and avoiding electrical hazards;
14



distinguishing exposed energized parts from other parts;
understanding approach boundaries; and
determining the personal protective equipment required for different tasks.
To conclude training sessions, team members must complete a written evaluation to verify that they
understand the material. Training records will be retained by the team, and each team member must be
safety certified at least once a year. Attendance and the participant’s signature will be recorded at each safety training. The attendance record will be placed in the team’s safety documents binder, in addition to their test paper as written documentation of the training performed. After necessary training, team members will be
considered as a qualified person to do work in and around the ESS.
Before initially starting a job, the electrical team lead shall conduct a simple job briefing with the team
members involved. This will be useful for identifying hazards, double-checking personal protective equipment,
and going over other safety and procedural measures.
Table 5. NFPA 70E Standard Approach Boundaries for Systems 301V to 750V
Distance
4 ft 0 in
3 ft 6 in
1 ft 0 in
0 ft 1 in
NFPA 70E Approach Boundary (301V to 750V)
Flash Protection Boundary
Minimum distance to receive 1.2 cal/cm^2 in an arc flash incident.
This will result in permanent injury if not wearing flame-resistant
clothing. Second degree burns.
Limited Approach Boundary
Minimum distance from exposed HV for an unqualified person to
stand, unless escorted by a qualified person.
Restricted Approach Boundary
Minimum distance from exposed HV without proper PPE. To cross
this boundary, the qualified person must wear proper PPE and
have proper tools.
Prohibited Approach Boundary
Beyond this boundary is the same as touching an energized
conductor. Crossed ONLY by a qualified person and requires the
same PPE as if contact was made with the live part.
PPE required
FR clothing
Eye protection
FR clothing
Eye protection
FR clothing
HV gloves
eye protection
FR clothing
HV gloves
eye protection
Team leads will be responsible for occasionally auditing team members to ensure that all safety measures are
adhered to when servicing the ESS and working in the high voltage area. No person shall assemble, service, or
disassemble the ESS or any electrical equipment or machinery unless he/she is trained and qualified for the
specific task being performed.
Team members who fail to obey safety and lock-out/tag-out procedures will be subject to a temporary
suspension from working in the HV area, including the ESS. This suspension will be lifted once a refresher
safety course is taken through EH&S. Failure to obey the written assembly and serviceability instructions will
result in the same temporary suspension, with the understanding that all written instructions are to be
properly followed. After two temporary suspensions, members will report to Faculty Advisor Brian Fabien to
discuss future disciplinary action. After three temporary suspensions, team members will be suspended from
the HV area for the current and subsequent academic quarter. Starting the day of a fourth suspension, team
members will be removed from the EcoCAR 2 team for an entire calendar year.
15
A.5.2 - Lock-out/Tag-out
When servicing the ESS, team members will be required to follow the lock-out/tag-out procedures outlined in
this section. The purpose of following these procedures is to prevent unintended release of energy. Locks are
placed so that no hazardous power sources can be activated, and tags are placed on the locked device to
indicate that it should not be turned on. Tags are only warning devices, and do not provide the same level of
physical restraint as a physical lock. Therefore, tags are secondary measures.
Lock-out/tag-out safety training will be conducted once a quarter through Environmental Health and Safety at
the University of Washington. Members who are not certified shall under no circumstances service any part of
the ESS unless training is complete. Jay Herzmark, Industrial Hygienist with EH&S, will conduct the trainings
specifically tailored to our team. The training course presents information about recognizing situations
involving hazardous energy, recognizing safety locks and tags, and how to respond in emergencies.
At the end of the lock-out/tag-out training, team members will:




Understand the purpose and function of an energy control program
Identify the type and magnitude of energy available from the ESS
Know the methods to isolate and control energy when servicing the ESS
Have a clear understanding of the prohibition against attempting to restart or re-energize the high
voltage system that is locked and/or tagged out
Team members servicing the ESS must use locks designated for lock-out/tag-out. Key locks will be used –
combination locks shall not be used in any circumstances. All locks must be Master Lock Pro Series 6835. All
locks used must be identified as a personal protection lock, and have the team member’s name and telephone number on it. Only one key to each lock will be provided to each person, and it must be kept in the pocket of
the owner at all times whens servicing the ESS to reduce risk of injury.
Tags shall be affixed that read “DANGER - DO NOT OPERATE,” date and time of installation, team member
name, and phone number. If more than one person is servicing the ESS, it is considered a multiple-person lockout and each person must place their own lock on the energy being controlled. When service is left unfinished
temporarily, such as overnight or a weekend, all locks and tags must remain in place until all work is complete
and it is safe to resume normal operations.
A.5.2.1 - Lock-out/Tag-out Procedure
A Before lock-out/tag-out
1. Verbally notify all affected team members in the HV area that you will be performing a lock-out
a. They must be fully aware that they are not to disturb the lock-out
b. They must not attempt to re-energize the system until the lock-out has been cleared and it is safe
to resume normal operations
B Initial lock-out/tag-out
1. Secure HV entrance, to prevent unqualified persons entering the work area
a. Place a “DANGER KEEP OUT” sign on the door
b. Close and lock door from the inside
2. Secure vehicle
a. Make sure ignition is “off”
b. Place car keys in lock box
16
c. Unplug charger from the wall outlet
i. Place plug into a plug lockout and secure with a personal lock
ii. If a multiple person lock-out, each team member must install their own lock
(a) Place key in personal pocket
iii. Lockout charger port, and apply necessary tag
3. Secure ESS
a. Lockout MSD
i. Place MSD into lock box with car keys and apply personal lock
ii. If a multiple person lock-out, each team member must install their own lock on the lock box
(a) Place key in personal pocket
iii. Lockout the MSD receptacle on the ESS, and apply necessary tag
b. Verify that the ESS system is locked out, and energy is isolated – do NOT assume that the lockout
was successful without confirmation
i. Remove lid
ii. Use a multimeter to test high voltage contactors to make sure they are not live
iii. Ensure with a multimeter that contactors are open at both positive and negative ends of the
EDM
C Service the ESS, following the Assembly and Serviceability procedures
A.5.2.2 - Concluding Lock-out/Tag-out
1. Ensure it is safe to re-energize ESS
a. Remove all tools from the area
b. Ensure that HV connections are not compromised
c. Confirm that the ESS is assembled properly, per assembly procedure
2. Install MSD
a. Verbally notify all affected team members in the HV area that you will be installing the MSD, and
re-energizing the ESS
b. If a multiple person lock-out, each team member must verify that they system is safe to re-energize
c. Remove locks from lock box
d. Remove locks from MSD enclosure
e. Place personal locks and keys in the lock station
f. Install MSD
3. Car Keys
a. Remove car keys from lock box
b. Place car keys in appropriate area
c. Return lock box to the lock station
4. Charger
a. Remove locks from plug lockout
b. Remove locks on charger port
c. Place personal locks and keys in the lock station
d. Connect charger to vehicle if necessary
5. HV entrance
a. Unlock door
b. Remove “DANGER KEEP OUT” sign and return to lock station
17
A.5.3 - ESS Failure Modes
There are many conditions that will lead to a fault in the ESS. Most of the faults resulting from these
conditions are handled directly by the BCM. Table 6, provided by A123, shows the faults that the BCM will
safely handle and how it will perform an Emergency Power Off (EPO) if necessary.
Table 6. EPO tests performed by ESS (from A123)
Although the BCM is programmed for fault mitigation through current limiting and EPO commands, it is far
more desirable to have the MABx anticipate the BCM fault conditions and take corrective action before an
EPO occurs. In addition, in the event of an EPO it is necessary to disable all modes that require non-zero RTM
torque. Table 7 describes the actions that the MABx will take to avoid an EPO as well as the mode shifts that
will take place in the event of an EPO.
Table 7. HSV response to fault signals from the BCM
Fault Signal
Source
Signal
Detail
BCM
bcm_lls_status
Liquid level in ESS
HSV Response
Signal Value
FAULT
BCM
bcm_epo
ESS Conducted EPO
BCM
bcm_alarm
BCM overall condition
BCM
bcm_ibat
ESS total current (+ = charge, - =
discharge)
Action
Stop ESS coolant flow
1
Switch to ICE-only mode
Type 3
> bcm_chg_max
Reduce regen-braking
< bcm_dis_max
Reduce motor power
BCM
bcm_soc
ESS SOC%
< 10%
BCM
bcm_cell_tmax
Highest cell case temperature
> 55C
BCM
bcm_cell_tmin
Lowest cell case temperature
< -10C
BCM
bcm_gfd
Ground fault detection result
< 170 kΩ
18
Request an EPO
A.5.4 - Fusing
We confirmed that the 250 A fuse supplied by A123 (See Appendix for ESS 250A Fuse Data) will satisfy our
pack requirements by verifying that the maximum voltage of the battery pack does not exceed the voltage
rating of the fuse. We also verified that the current rating for the fuse is at least 25% higher than the
continuous current of the pack. The continuous (RMS) current required from the battery pack is 128 A. Using
of factor of safety, the continuous current is within the 250 A rating of the fuse. In order to make sure the fuse
will not blow at our peak simulation current of 426 A for 10 seconds on the US06 Highway Cycle simulations,
we reviewed the time vs. current graph at 426 A. We found that the fuse will take approximately 200 seconds
to blow. This shows that the 250A standard fuse does not protect against high demand transients, but is much
better than the 350A fuse which will take over 1000 seconds to blow at 426 amps. We are interested in
selecting the 250A fuse instead of the 350A fuse that is supplied with the ESS.
After a fuse has blown, there is still a potential difference across it. On all components, fuses are chosen with
both voltage capacity and current level in mind. Failure to address the high voltage across a blown fuse can
result in an arc of current that may complete the circuit even after the fuse has blown. The high voltage
battery enclosure will be outfitted with a non-resetting current-limiting fuse. This fuse will be connected in
series halfway through the battery string inside the battery enclosure. In the event that the fuse blows, it must
interrupt the complete short-circuit current of the battery.
Fuses are rated in terms of both the maximum current allowed and how large a voltage drop they will
withstand after interrupting a circuit. The ampacity of the fuse must be lower than or equal to the protected
wire, and the voltage rating must be higher than the open circuit voltage. Furthermore, we contacted A123
and found that each individual pack has a fuse, as well as each cell in the pack. If for any reason one of these
fuses should blow, the module must be serviced or replaced.
A.5.5 - Clearance and Creepage
All high voltage circuits will be isolated from the vehicle chassis and all low voltage circuits in the vehicle. In
particular, high voltage circuits will not be grounded to the chassis, to avoid the risk of shocking a passenger.
The current sense module in the A123 battery pack has built in ground fault detection to make sure isolation is
maintained. The isolation level will be maintained at 500 Ω/V at all times according to the non-year specific
rules. This isolation level prevents electrical creepage between the high voltage circuit and ground, and
prevents ground faults which can cause a short circuit or injure a passenger.
Table 8. HV and LV Circuit Separation
Voltage (V)
Spacing (cm)
<100
1
100-200
2
>200
3
High and low voltage circuits will not be run through the same conduit or cord grip, with exception to the HVIL
line. If both high and low voltages are present in the same enclosure, they will physically maintain the spacing
outlined in Table 8, above. Furthermore, A123 recommends at least a 4 inch through-air separation for high
and low voltage components. With that in mind, we will keep a minimum 4 inch through-air separation
distance between all high and low voltage components within the ESS.
19
In addition, there is a minimum spacing between any insulated, energized part and conductive material, or
between two parts of different polarities. This spacing prevents accidental contact, or arcing. Table 9 outlines
the minimum spacing to prevent accidental contact.
Table 9. Minimum Spacing to prevent Accidental Contact
A.6 - CAD
A.6.1 - Mounting
The mounting design for the ESS consists of three long bars and two cross bars. These steel crossbeams are
specifically C-channel A36 steel bars. The steel crossbeams weld directly to the section of the vehicle frame
that extends the belly of the trunk floor. We chose steel as the final material choice because of the need to
weld to the frame. The use of C-channel bars was selected as to have access to the bolts when installing and
removing the ESS. As a note, the steel crossbeams will be cut where they intersect the vehicle frame and will
then be welded to each side of the point of intersection as to provide sufficient support to the ESS. We will
not be cutting the vehicle frame.
Figure 3. Mounting of the ESS inside the Vehicle Trunk
Located beneath each battery are two slotted battery mounts, one at each end of each battery module. These
were incorporated at the recommendation of A123 Systems due to the varying length of the batteries. The
CAD that was given to us by A123 Systems depicts the batteries at their maximum lengths, but they may be as
much as five millimeters shorter than depicted in the CAD. These brackets accommodate variable length
20
batteries. The batteries are mounted to these 14 slotted battery mounts and the 14 slotted battery mounts
are bolted to the C-channel A36 steel structure.
Figure 4: Internal Pack Layout
Figure 5. Mounting of the Battery Modules
The plastic supports depicted in Figure 5 provide a mounting structure for the wire routing. Because of the
need to incorporate these plastic supports, six spacers and six longer bolts were necessary in a few instances.
A.6.2 - Crush Zones
The ESS was designed and mounted to meet many criteria. One of the main criteria was to ensure that the
ESS remained outside of the crush zone.
21
Figure 6. The ESS is situated well outside the crush zone
A.6.3 - Venting and Sealing
A venting route has been designed to direct hydrogen gas out of the ESS enclosure to the atmosphere. The
venting route includes a bulkhead fitting exiting the side of the ESS enclosure and connected to an in-line
pressure relief valve. Rubber tubing then routes the gas exiting the low-pressure relief valve through the trunk
floor to the atmosphere. A low-pressure relief valve was selected to prohibit the entrance of sand, dust,
condensation, and salt fog. The pressure will be set so that the valve will open before any other seal in the
pack fails. Based on the expansion of air during normal operating temperatures, 4 psig was calculated to be an
adequate release pressure for the valve. The valve is detailed in the previous.
22
Figure 7. Venting Strategy with Lid Gasket, Detailed Pressure Relief Valve
A.6.4 - Component Layout
The high voltage components are positioned at the same level as the battery modules. The CSM, and EDM
components will be mounted on spacers 1.5 inches above the aluminum base to keep them above the cooling
plate fluid reservoirs. The BCM will be mounted on the sidewall of the front of the battery pack. All of the high
voltage control components are located as far back as possible in the trunk of the vehicle to provide easy
serviceability.
The high and low voltage connectors provide easy access for servicing the ESS, and will be mounted on a small
plate with a sealing gasket. The MSD is located directly above the high and low voltage connectors to provide
access to both important components for ESS service. Furthermore, the MSD is located on the lid of the
enclosure for both a clear visual reminder to remove the MSD, and to guarantee the MSD is removed before
the ESS can be serviced.
The two module cooling plates are located on the bottom of the battery modules. The four coolant outlets will
emerge from the bottom of the battery pack enclosure towards the center of the pack so they do not interfere
with the frame rails. Each coolant port outlet will have sealing O-rings. Coolant routing between plates will be
external to the battery enclosure. This is intended to provide safer operation because the port connectors can
be prone to failure.
23
Figure 8. ESS Component Layout
A.6.5 - Electrical Routing
High voltage cables are routed with several goals. First, HV cables are routed to minimize the length of the
actual wires. As seen in Figure 9, the location of high voltage and low voltage components are placed to
minimize the distance between wires. For example, the MSD is strategically placed to simplify the high voltage
wiring in that the only lengthy HV cables run vertically down the center of the lid. Along with minimizing the
length of HV wires, the high voltage routing is placed to maintain a 4 inch separation between high voltage
and low voltage wires. In addition, low voltage and high voltage wires only cross in two locations within the
battery pack. In order to add structure and ensure that HV and LV cross orthogonally, three diagonal plastic
plates have been added to the pack that will support plastic fixtures.
24
Figure 9. Trimetric View of Electrical Routing
The organization of the HV and LV components allow the low voltage wires in conduit to span the perimeter of
the pack in Figure 10. The precision of the placement of LV wires will be greatly improved by the added plastic
structure that will add a number of permanent fixtures. Figure 10 illustrates the wire routing of the HVIL and
low voltage routes between the BCM, CSM, and EDM.
Figure 10. Top View of Electrical Routing
25
A.7 - Protection
A.7.1 - Load Analysis
Load analysis results can be found in Error! Reference source not found. ESS Mounting Design.
A.7.2 - Sealing
The ESS enclosure will be sealed to prevent the entrance of sand, dust, condensation, and salt fog. A robust
sealing strategy will not only protect the internal components of the ESS enclosure, but it will also serve to
prevent hydrogen gas from being vented into the passenger compartment in the instance of a battery cell
malfunction. All of the ports to connect to external wiring and coolant lines will be sealed with gaskets. A butyl
rubber gasket will be situated between the top and bottom lids of the ESS enclosure, as well. This gasket
material was selected because it has very low permeability to air. It is nearly airtight and gas impermeable.
Also known as isobutylene isoprene, it combines good weather and oxidation resistance. It also has excellent
resistance to alkalis and acids. CAD depicting the rim gasket can be found in Figure 7. Self-sealing bolts have
been utilized in all instances of bolting through the ESS enclosure. These gaskets will be sufficient for the
pressures, temperatures, and chemicals that will be present in the pack.
A.7.3 - Vibration and Damping
Studies were found while researching active and semi-active suspension controls that include Simulink spring
mass constant models for ground based vehicles. We require accurate vehicle chassis mass, vehicle front and
rear suspension masses, as well as rigidity coefficients of the wheels and suspension to determine resonant
frequencies and vertical acceleration due to vibration.
Using Equation 1 below, obtained from the Journal of Dynamic Systems and Measurement (Choi, 2000), we
can use a random excitation road profile input in the model provided in the study to obtain a vibration profile.
This can be done once the required vehicle specs are obtained.
Equation 1: Active Suspension Vibration Profile Equation
̇ +
Vibration isolation and analysis goals of the team have changed in the last revision of the non-year specific and
yearly specific rules. Required vibration isolation of the pack from the vehicle chassis is a constraint that has
been lifted. A123 recommended that we remove our battery mounting dampers at our design review during
winter workshop.
Our vibration damping approach is to mount the ESS directly to the frame of the vehicle. This will give the ESS
a vibration profile that is the same as the vehicle’s suspension because the components will be bolted directly to steel cross members located in between the vehicle frame rails. The location we chose to mount the ESS in
the vehicle also plays a role in vibration protection of the pack. Placement of the battery pack directly above
the rear tires minimizes vibration by eliminating the cantilevered moment that would exist if the ESS was
mounted further behind the rear tires.
26
A.8 - Thermal Analysis
A.8.1 - Concept and Design
The proposed ESS cooling loop design includes cooling for the battery pack, RTM, and RTM inverter. It uses a
solution of water and ethylene glycol in equal amounts by volume. To dissipate heat, both the low
temperature radiator in the front of the vehicle and a heat exchanger connected to the AC loop would be
used. Under conditions with sufficiently low ambient temperatures, the radiator alone (with a fan to increase
air flow) would be used to dissipate heat from the cooling fluid. In areas with high ambient temperatures, the
heat exchanger would be used in addition to the radiator to transfer heat from the ESS cooling fluid to the
fluid in the AC loop. This design is shown in Figure 11 below in schematic form, with the given pipe sizes
representing the inner diameters of the pipes.
The use of the existing low temperature radiator is possible if the only stock component being cooled by it is
the BAS, which will not be included in the final design of UW EcoCAR. After reviewing the CAD model of the
cooling loops in the Chevy Malibu Eco, it was difficult to decide whether the BAS was the only component that
was being cooled by this radiator because of an interference with the fluid lines near the surge tank.
Contacting a GM specialist on the cooling system might be able to clarify which components are being cooled
by which radiator.
The chosen pump is the Engineering Machined Products WP29 CAN-enabled electric water pump, which can
vary the flow rate output via CAN commands from the MABx.
PUMP
LOW-TEMP.
RADIATOR
DEGAS
BOTTLE
EVAPORATOR
RTM
AC
COMPRESSOR
HEAT EXCHANGER
ESS
RADIATOR
EXPANSION VALVE
Pipe Size Key
1 in.
Thin Degas
Bottle Tube
.875 in.
AC Loop
.5 in.
Figure 11. Heat Exchanger Cooling Loop Schematic
27
A.8.2 - Heat Generation and RMS Power
Total thermal generation and cooling requirements of the designed loop were obtained from modeling and
from direct instruction from organizers. A123 stated that the expected thermal generation from Charge
Depleting (PHEV / EV) operation is about 2.5W/cell, and the thermal generation from a Charge Sustaining (HEV
mode) mode of operation is about 5W/cell. This is reasonable because during HEV operation more energy is
being regenerated by the pack, which causes more heat generation than discharging.
These values lead to approximately 1500W battery power plus 300 Watts for the high voltage control
components. The calculated continuous battery power output for this team’s ESS is only 40.8 kW, so the 1500 W figure provides a good factor of safety for the design.
To determine the heat generated by the RTM and inverter, the RMS power for each and the respective
efficiencies were used to find thermal generation. With RMS powers of 34.6 kW and 35.7kW for the RTM and
controller respectively, and efficiencies of 91.2% and 97% yield the calculated heat loads of 3044 W and 1071
W. This results in a total heat load of 4115.8 W for the RTM and controller.
Combining the heat loads from the ESS, RTM and controller, the total heat load is 5915.8 W.
A.8.3 - System Bleed Process
To bleed the cooling system properly, a degas bottle would be connected to the highest point on the lowtemperature radiator to remove any air in the system. This degas bottle would then be connected to the line
exiting the radiator.
A.8.4 - Cooling Plates
In correspondence with the final ESS layout, the final cooling plate concept uses 2 plates: one large plate to
cover the six batteries grouped together, and a small plate to cover the seventh battery that lies off to the
side. The current design places the plates in series; that is, the coolant passes through the small plate before
proceeding to the large plate. This design is shown in Figure 12 below.
Figure 12. Final Plate Design
28
A.8.4.1 - – CFD Analysis and Head Loss
A steady-state computational fluid dynamics analysis of the cooling plates was performed (note that this
analysis includes the heat load of the ESS only, and does not include the heat load from the RTM). The coolant
inlet temperature used was 30 oC. A total heat load of 1500 W was used, with 215 W distributed over the
small plate and 1285 W distributed over the large plate (215 W per battery in contact with the plate). This
analysis indicates that this design has a total head loss through the plates of 4.71 kPa, which is well within the
range that is required for the selected pump. The difference in fluid temperature from inlet to outlet is only
1.78 oC, which indicates that the batteries are being cooled efficiently. Pressure and temperature distributions
of the fluid in the cooling plates are shown in Figure 13 and Figure 14 below.
Figure 13. Pressure Distribution in Final Plate Design
Figure 14. Fluid Temperature Distribution in Final Plate Design
29
A transient simulation was also run because it provides a more accurate simulation for the maximum load
scenario. The only time that maximum load is expected is during an acceleration test, which will not be long
enough in duration for the system to reach steady-state. The inlet coolant temperature used was 40 oC. The
time steps taken were 0.5 seconds each, and the simulation was run until it reached 10 seconds. After 10
seconds, the average coolant temperature only increased to 41 oC. The cooling plates had the temperature
distribution shown in Figure 15.
Figure 15. Transient Fluid/Plate Temperature
As expected, the outer edges of the plates have the highest temperatures. The maximum temperature that
the cooling plates reach at any location after 10 seconds is 314.4 K, or 41.4 oC, which is within the operating
range of the battery pack.
A.8.5 - Cooling System Load
The cooling concept must provide adequate cooling throughout all possible environments. In our case, the
extreme was taken to be
F to represent in Yuma Arizona during Year 2 Competition. Because this is
above the maximum inlet temperature of the cooling plates, the AC compressor must be able to satisfy the
entire cooling demand in the steady state situation as if there was no radiator. With the maximum RMS
thermal generation of 5915.8W, the AC compressor is able to satisfy the entire demand at approximately 66%
maximum throttle of 9kW peak at a COP of 1.81. This also allows for 3kW of cooling to the passenger cabin.
30
A.9 - Charger
The University of Washington team selected the two-fan side-cooled NLG513-Sx Brusa charger. The provided
Brusa charger meets all the EcoCAR charger specific requirements. The charger will be mounted onboard the
vehicle at the rear of the vehicle adjacent to the A123 battery pack.
The air-cooled version was selected to simplify the onboard cooling loop and to reduce friction head losses.
The charger is not required for normal on-road operations, and the powertrain must be disabled when
charging, so including it in the main cooling loop is not practical. The charger is compatible with 110V, 208V
and 240V outlets, and is J1772 compliant. The charger output varies from 260VDC to 520VDC and peaks at
3.3kW at 90-93% efficiency. The charger can operate at full power from 260-378 volts and outputs a maximum
of 12.5A at our voltage specifications (see Figure 16).
Figure 16. BRUSA Charger Specifications
Because of the fan model’s lower IP54 ratings, additional considerations will be taken to protect the charger from moisture and outdoor air.
A.10 - Electromagnetic Interference (EMI) Compliance
Electromagnetic compatibility (EMC) is the ability of a component to function in its electromagnetic
environment. As applied to the hybrid vehicle, there are many components in close proximity to each other
that generate electromagnetic fields, and it is paramount to safety and smooth operation that these
components are compatible in their final electromagnetic environment. The primary concern of EMC is under
the undesired condition that one component causes unintended operation via electromagnetic fields in
another component, a phenomenon called electromagnetic interference. For further analysis, it is convenient
to break EMI into the source, path and receiver. The source is the generator of EMI (high power, rapidly
varying signal), the path is the mechanism by which EMI transports (conductive, capacitive, and inductive) and
the receiver is the victim of EMI, e.g., communication signals (Figure 17. EMI Coupling Modes).
31
Figure 17. EMI Coupling Modes (Electromagnetic Compatibility)
Identifying components that are expected to be sources, paths and victims is critical to EMI reduction. For
example, power devices such as the RTM system and the A123 battery pack were identified as sources and
communication devices such as CAN wires were identified as victims. Ultimately, the goal of EMI reduction
reduces to eliminating and obstructing EMI paths. Based on recommendations from A123 systems, Remy, and
other research, reducing EMI is best accomplished by applying wire routing techniques, component and wire
shielding, and carefully grounding high current wires. All of our CAN wires will be shielded twisted pairs to
reduce noise from other components.
The RTM inverter is expected to be the most impactful generator of EMI noise. To ensure noise reduction, the
inverter was verified to have conductive shielding. The three AC cables it outputs will be shielded with
grounded conduit. The ESS will output a DC signal, and is thus predicted to generate minimal noise relative to
the RTM system; nevertheless, the bottom of the ESS enclosure was chosen to be conductive and grounded to
the chassis. Wires susceptible to EMI, i.e., the LV and CAN wires, are routed at least 4 inches from ESS HV
cables within the ESS enclosure. Another measure to reduce susceptibility in CAN communication is the use of
shielded twisted-pair wires.
In three cases, the crossing of LV and HV cables was unavoidable; the wires involved were crossed
perpendicularly in an effort to reduce coupling. In reference to our battery pack design, HV cables were routed
with a goal of minimizing cable lengths, and HV modules were placed to maximize flexibility of wire routing if
EMI becomes an issue during construction and testing phases. To minimize EMI within the LV system, high
current grounds will be places as far as possible from signal grounds. Also, no filtering systems are planned to
be used but will be considered as an option if EMI is identified as an issue.
A.11 - Assembly and Serviceability
A.11.1 - Safety Precautions and Risk Management
Two main hazards presented by energized electrical equipment: direct contact or coming too close to exposed
live parts, and arc flashes. You must be fully aware and educated of all safety concerns and hazards before
performing any service on the ESS. See the lab schematic and locate the first aid kit, phone, eyewash, chemical
shower, fire extinguisher, spill kits, and all exits. Emergency procedures and contacts must also be known.
32
Table 10. HV Battery Pack Information
Battery Pack Voltage
378 V Max 340 Nominal
Number of LiFePO4 Battery Modules
LiFePO4 Battery Module Voltage
7
48.6 V Nominal
A. ALWAYS ASSUME THE VEHICLE’S HIGH VOLTAGE SYSTEM IS ENERGIZED
B. Clearance and Certification
1. Review clearances and certification to be working in a high voltage area for yourself and those working
with you.
2. You must be lock-out/tag-out and trained for high voltage operation.
C. Signage
1. Always put signs up when you are working on High Voltage
2. Always remove signs when you are done working on High Voltage
D. Personal Protective Equipment (PPE)
1. Remove all articles of jewelry, watchbands, bracelets, rings, necklaces and all other conductive clothing
2. Long hair must be tied back
3. FR clothing, HV gloves, and eye protection per approach boundaries as outlined in the “Qualifications” section of the UW Ecocar2 Safety Manual
4. Hearing protection
a. In environments where a sound level survey has detected a decibel level of 115 dB or more for any
length of time; or the environment, equipment or processes within are expected to expose
personnel to at least 8 hours of noise at 85dB or more, single hearing protection is required.
5. Footwear
a. No open toes or weaves
b. Non-conductive footwear is required when working around high-voltage components.
c. Impact resistant toes-the shoe/boot will be marked as meeting ANSI Z41 or ASTM F-2412
6. Gloves
a. High Voltage gloves must be worn at all times when servicing ESS - but NOT when operating lift
b. Inspect for holes or wear in gloves before use
c. Store in appropriate container
7. Clothing
a. Flame Resistant clothing must be the outermost layer of clothing
b. Wear clothing with natural fibers
c. Clothing that becomes contaminated with grease, oil, or other flammable liquid or combustible
material shall not be worn
E. Battery Handling
1. Cover with insulated blanket when transporting batteries on high voltage cart
a. Always orient batteries right side up
b. Do not stack batteries
2. Do not drop batteries
a. Slide high voltage cart to the rear of car and transport batteries to and from trunk. Do not carry
over floor
3. Never touch battery terminals or touch battery terminals to each other
33
4. Batteries are heavy and weigh 60.94 lbs each. When tightening components, make sure gloves are not
caught in between hardware
F. Tools
1. Use high voltage insulated tools at all times when working inside of pack
2. Always ensure your tool is the right tool for the job, is in good repair and that your use of it and
personal protective equipment (PPE) is appropriate before use
3. When not using a tool
a. Return tool to high-voltage toolbox. DO NOT leave tool in/on the car/ESS
b. Ensure that all tools are removed from areas where their presence may create a hazard if not
controlled. Flying wrenches and other tools are effective missile hazards. It is best practice to
conduct a tool sweep at the end of every day and ensure tools are put away properly to prevent
this
G. Conduct
1. Never work alone
2. Only use one arm when working inside the battery pack to prevent a short circuit with one’s body
3. No use of cell phones
4. Announce in a loud voice when MSD is being reinstalled, or contactors are closing
5. Avoid extra people near the car when closing contactors
6. Don’t reach blindly into areas that might contain exposed live parts
7. Provide illumination in spaces to enable safe work
8. Make sure to be physically and mentally capable for the task
A.11.2 - De-energize system (Preparing to service or disassemble ESS)
1. Disconnect charger from wall outlet
2. Make sure vehicle is powered off
3. Remove Manual Service Disconnect (MSD)
a. This should be the first part removed from the ESS
4. Disconnect battery from high voltage bus with Tyco connector
5. Remove low voltage connector
6. Remove lid
7. Test high voltage contactors to make sure they are not live
a. Use a multimeter to make sure contactors are open at both the negative and positive ends of
the EDM
8. Adhere to Lock-out/Tag-out procedure
A.11.3 - Assembly
1. On high voltage cart, fasten high voltage control modules (BCM, EDM, CSM) to mounting plates
a. Fasten battery control module to specified location on plate
b. Fasten electronic disconnect module to specified location on plate
c. Fasten current sense module to plate to specified location on plate
d. Connect CSM bus negative to EDM bus negative
e. Connect EDM Bus positive and negative to Tyco pack connector
f. Attach low voltage harness to CSM and BCM
2. Insert aluminum base enclosure into vehicle
34
3. Insert and secure internal battery modules
a. Insert battery mounting brackets and bolt through base to the steel cross beams
b. Insert cooling plates
i. Insert air tight gasket for coolant outlet and inlets
ii. Place large cooling plate under batteries 1-6 between each row of slotted battery brackets
iii. Position small cooling plate 7 between slotted battery mounts for battery 7
c. Place battery modules 1-6 in their place on top of the battery mounting brackets
i. Fasten battery modules to aluminum base enclosure
ii. Observe diagram for individual placement
d. Place battery 7 in place on top of cooling plate 7
i. Fasten to battery enclosure
4. Insert and secure high voltage control modules
a. Place high voltage control modules in ESS and bolt them to the base enclosure
i. Make sure to place sealing gaskets and lock washers in appropriate order
b. Route high voltage lines according to diagram
c. Connect bus bars according to diagram
d. Route low voltage wires to appropriate locations within battery and to battery control module
5. Insert and fasten the Tyco high voltage connector and low voltage connector
6. Insert gasket to seal the ESS enclosure
7. Set top lid in place
8. Bolt MSD receptacle to lid
9. Insert and tighten bolts to secure top and bottom lids together
10. Go to Re-energize system
A.11.4 - Disassembly
A Follow De-energize procedure
B Place all removed components and hardware either on workbench or HV cart. DO NOT leave them around
the ESS
1. HV control modules
a. Remove HV lines
b. Remove LV lines within battery and to BCM
c. Disconnect bus bars
d. Remove HV control modules
2. Unfasten batteries 1-7 from aluminum base enclosure
3. Remove battery 7 from aluminum base and place on HV cart
4. Remove batteries 1-6 in no specific order and place on HV cart
5. To remove battery enclosure:
a. Disconnect coolant lines and drain coolant
b. Remove cooling plates and coolant gaskets from the aluminum base
c. Remove all battery mounting brackets
d. Remove remaining mounting hardware and gaskets from aluminum base enclosure
e. Unbolt aluminum base enclosure from steel cross bars
f. Remove aluminum base enclosure
35
A.11.5 - Service
1.
2.
3.
4.
5.
Follow lock-out/tag-out procedure
Follow De-energize procedure
Perform service
Disconnect coolant lines and drain coolant
If servicing thermal management system
a. Remove cooling plates and coolant gaskets from the aluminum base
b. Refill coolant reservoir
6. Follow Re-Energize system
7. Log who serviced the ESS and what work was performed
A.11.6 - Re-Energize System (Preparing to Energize Vehicle)
1. Attach high and low voltage connectors to ESS
2. If ESS is locked out, follow section: Concluding Lock-out/Tag-out. Else continue to step 3
3. MSD
a. This should be the final part placed on the ESS
b. Verbally announce to HV area that MSD will be inserted and system will be re-energized
c. Insert MSD to MSD receptacle
36
A.12 - Bill of Materials (BOM)
37
Item Type
Case and Mounting
Plastic enclosure
Aluminum Tub
Enclosure Screws
Enclosure Nuts
Steel C Channel
Steel C Channel
Battery Modules
Brackets
Bolts
Extra Long Bolts
Spacers
Lock Nuts
Bolts
Lock Nuts
Sealing/Venting
O-ring
Bulkhead Fitting
Elbow
Pressure Relief Valve
1/8" NPT to hose adapter
Rubber hose
Hose clamp
Rubber grommet
Enclosure Gasket
Wiring and Connections
High Voltage Wires
90 Degree Lug
1/0 Wires
Plastic sheet (cable holders
Cable holders
Fasteners
1/0 Double Lugs
Low Voltage Wires
16 gauge
18 gauge
20 gauge
Conduit
Bus Bar Bolts
Bus Bar Lock Washers
Terminal Bolts
Terminal Lock Washers
Current Sense Transducer
Copper Bus Bars
Heat Shrink Kit
HV Pack Connector
LV Voltage Connector
Motor Disconnect
HV Test Connector
HV Test Connector
HV Test connector
Locking Nuts
Locking Nuts
L-Bracket Lugs
(EDM)
Bolts
Locking Nuts
Spacer
1/0 Single Lugs
Bolts
Locking Washers
1/0 Single Lugs
Lug Locking Washers
Lug Nuts
Cooling System
Gasket
Cooling Plate
Cooling Plate
Cooling Plate
Cooling Plate
Pump
Heat Exchanger
Tubing
Location
Supplier
Part #
Cost
1 sheet
2 sheets
38
40
1200 mm X 1000 mm X 3.175
36"x48"x0.1"
M8 L=10mm
Trunk Space
Trunk Space
Pack Enclosure Rim
Emco Industrial Plastics
Online Metals
McMaster
4335-2566-.125-HC
S52.1H36x48x.01
93635A305
$142.00
$32.24
38
50
M8, h=8mm, w=13mm
Pack Enclosure Rim
McMaster
94205A260
$14.88
1 bar
1 bar
7
14
22
6
6
28
28
28
4'
8'
2" {A} x 1" {B} x 0.188" {C}
3" {A} x 1.410" {B} x 0.170" {C}
24
8
2'
30
30
50
3 cm X 15 cm
M10 L=200 mm
M10 L=265 mm
L=approx 63mm
M10
M10 L=25 mm
M10
Trunk Space
Trunk Space
ESS
At each Vertical Battery
Speedy Metals
Speedy Metals
A123
Metals Depot
McMaster
McMaster
Online Metals
McMaster
McMaster
McMaster
hc2x1x.188-48
hc3x4.1
N/A
P1316
91290A564
91290A567
L2.OD.625ID.495
94920A600
95430A383
94645A220
$13.33
$49.92
Donation
$21.52
$89.52
$29.84
$10.59
$19.53
$14.61
$18.56
McMaster
Sure Marine Service/Brass
Summit Racing Equipment
Gererant
Wholesale Marine
Find It Parts
Wholesale Marine
Chevy-2-Only
McMaster
5240T11
22305x2
HLY-26-69
VRVI-125-B-V-4
033432_10
27304
18-7307
23034
8609K29
ESS
McMaster
Champ Cable
McMaster
6926K62
EXRAD-XLE6-1/0X
2898K17
Plastic Sheet
McMaster
Cable Hold Downs
Boltaron 4335
Aluminum 5052
316 Stainless Steel
Metric Nylon-Insert Hex Locknuts, Type
316 Stainless Steel
Steel
12.9 Alloy Steel
12.9 Alloy Steel
Stainless Tube 304/304L
Serrated-Flange Hex Locknuts
High-Strength Steel—Class 10.9
Aflas
Brass
25
Butyl Rubber
1
1
1
1
1
1 ft
1
1
1 Sheet
Copper Long Barrel
HV wires
Chemical-Resistant Polypropylene,
1
3m
3
2
1 Sheet
White Nylon
10
50
Barrels: polyethylene, Screws: nylon 6/6
MagnaLugs NEMA 2 Hole
10
4
100
Break Pressure: 4 psig (but adjustable)
PVC
Stainless
Stainless
Copper Sheet
Orange, Tube Size : 3/4", Flat Diameter : 1
3/16", Shrink Diameter : 0.375"''
Tyco
Yazaki
3P Manual Interlock Motor Connector
Box mount receptacle
Straight plug
Protective Cap
12'
14
14
14
14
1
6
25'
25'
25'
25'
50
100
50
100
1
12"x48"
1
2'
1/8"
Bulkhead Fitting
1/8" NPT inner
Side of battery pack
1/8" NPT
Into bulkhead fitting
1/8" NPT,
Into elbow
1/8" NPT
Into pressure relief valve
5/16" inner dia.
Hose Adapter
For 5/16" fuel line (about .56")
Hose
For 5/16" fuel line
Trunk floor
48" x 36"x1/16"
Pack Enclosure Rim
OD: 12.70 mm
24"x24"x1/8"
Bundle Size: 1/2", 13/64" dia.
mount hole
L=1/4"
OD: 0.077"
OD: 0.068"
OD: 0.058"
1/2"
M6 L=10 mm
M6 1.5 mm thick
M6 L=10 mm
M6 1.5 mm thick
130mm X 21 mm X 5 mm
1
1
1
1
1
1
1
Zinc Yellow-Chromate Plated Grade 8
Steel
Current Sense Module (CSM)
Bolts
Size
Quantity
Battery Control Module (BCM)
Bolts
Purchase
Quantity
Item Specifics
$2.44
$3.94
$2.18
$0.99
$72.36
$17.20
$15.51
$7.26
McMaster
A123?
7572K14
90249A225
N/A
$8.82
Donation
ESS
ESS
ESS
ESS
ESS
McMaster
McMaster
McMaster
McMaster
McMaster
McMaster
McMaster
McMaster
LEM
Rotax Metals
69835K764
69835K754
69835K744
8067K111
92000A420
92153A426
92000A420
92153A426
N/A
C101.H02.12x48
$11.55
$9.45
$5.79
$21.50
$10.36
$6.42
$10.36
$6.42
Donation
$225.09
Keep it Clean Wiring
KICHSOR0750
$5.94
ESS
ESS
ESS
ESS
ESS
ESS
A123
A123
A123
Amphenol
Amphenol
Amphenol
N/A
N/A
PBT-GF30
97-3102A-14S-1S
97-3106A-14S-1P
9760-14
Donation
Donation
Donation
ESS
A123
N/A
Donation
5
5/16" L=1"
BCM
McMaster
92205A583
$18.45
5
5/16"
BCM
McMaster
ESS
A123
N/A
Donation
$11.55
1
Stainless Steel
$6.96
$3.25
97135A220
$19.00
5
1/4" L=3/4"
CSM
McMaster
92205A540
5
1/4"
CSM
McMaster
90099A029
$3.32
CSM
A123
N/A
Donation
2
2
Stainless Steel
18-8 Stainless Steel Unthreaded Spacers
Magnalug 1/0 gauge
Plug assembly, 350 A, MSD
Receptacle assembly, 350 A, MSD
Class 12.9 Alloy Steel
MagnaLug Sight Hole
5
Butyl Rubber
Engineered Machined Products
Everhot
Everhot
4
5
4
2
2
4
4
2
2
2
1
1
CSM
A123
N/A
Donation
1/4" L=2 1/2"
EDM
McMaster
92205A555
$17.75
1/4"
EDM
McMaster
5
L=1 3/8"
1/2"
100
100
5
100
50
M6 L=15 mm
M6 1.5 mm thick
1/4"
M6 1.5 mm thick
M6
EDM
EDM
ESS
ESS
MSD
MSD
MSD
MSD
MSD
McMaster
Grote Industries Inc
A123
A123
McMaster
McMaster
Quick Cable
McMaster
McMaster
90099A029
92320A914
GRO84-9204
1-2103172-1
1-1587987-1
91290A320
92153A426
8810-005D
92153A426
94150A345
Donation
Donation
$7.87
$6.42
1 Sheet
1 Sheet
1 Sheet
1 Sheet
1 Sheet
48" x 36"x1/16"
14”x39”x0.375” 14”x39”x0.125”
7”x17”x0.375”
7”x17”x0.125”
~5in Diameter x 5in length
3” x 3” x 8”
1” Diameter
Cooling Exit Ports
Cooling Plates
Cooling Plates
Cooling Plates
Cooling Plates
McMaster
Online Metals
Online Metals
Online Metals
Online Metals
Cummins Northwest
Pex Universe
Pex Universe
8609K29
as14x39x.375
as14x39x.125
as7x17x.375
as7x17x.125
WP29
HX5x12-20
BPR1001
$72.36
$223.86
$70.98
$38.08
$19.04
$194.00
$109.95
$89.95
1
100'
38
$3.32
$34.05
$6.42
$9.58
A.13 - High Power Electrical System
The high-power electrical schematic at the vehicle level is shown in Figure 18 below.
TTR HV Schematic
Legend
18 AWG
LV Battery
Bus Bar
Bus Bar
Bus Bar
5A FUSE
Bus Bar
Charger Switch
Bus Bar
18 AWG
250A FUSE
EDS Rear
MSD
AWG 1/0
AWG 1/0
CSM
HV NEG
HV POS
EDS Front
BCM
Control Signals
EDM
Inertial Switch
A123 Battery System
18 AWG
HVIL
HV Connector
Low Voltage Wire
High Voltage DC Positive
High Voltage DC Negative
AC Cable
Manual Switch
Switch
A123 Module
Manual Service Disconnect
Current Sense Module
Measurement and Balance Board
Battery Control Module
Rear Traction Motor
RTM Inverter/Controller
DC-DC Converter
Onboard Charger
Air Conditioning Pump
Air Conditioning Module
Emergency Disconnect Switch
MSD
CSM
EDM
MBB
BCM
RTM
RTMM
DCDC
CCM
ACP
ACM
EDS
AWG 1/0
CCM
ACP
ACM
FUSE 25 A
FUSE 15 A
AWG 12
FUSE 15 A
AWG 8
Air Conditioning System
12V ESS and
Accesory
System
AC Charging System
FUSE 200 A
FUSE 8 A
DC/DC Converter (340/12 V)
AWG 12
HV Rear Junction
AWG 18
AWG 1/0
HV Front Junction
RTMM
Shielded
2/0
RTM
RTM System
Figure 18: Vehicle Level High-Voltage Schematic
The following high voltage components will be used in the University of Washington’s high power electrical system. Their costs and vendor are outlined in Table 11 below.
Table 11. High Power Components
When placing fuses in a circuit, they will always be placed as close as possible to the positive side of the load.
They are placed this way so the load will be completely de-energized after the fuse opens, and to eliminate
dangerous voltages from either side of the load to the ground. Fuses will also be placed wherever there is a
change in cable size, to prevent a wire failing before a fuse blows.
39
In order to safely size all of the fuses, we multiplied the circuit’s continuous current by a factor of 1.25, then
rounded up to the nearest common fuse size. The factor of 1.25 is based off the NEC standard method of fuse
sizing. We also verified that all of our high voltage fuses are rated higher than our pack’s simulated max voltage of 378V DC.
Additionally, fuses are selected through examination of their respective time-current graphs in order to
determine how the fuse is projected to blow. A fuse must immediately interrupt a short circuit, to prevent
potentially lethal damage. However, slow blowing fuses have been placed throughout the vehicle between
components that will see a peak current that is higher than its continuous current. Table 12 below, shows the
various fuse choices.
Table 12. Fuse Sizing
In order to ensure that each wire is protected by its respective fuse, we sized the wire to an ampacity that is
1.5 times the continuous current through the wire. We then located the calculated ampacity in the NEC Table
310-16 @ 60° C and chose the corresponding wire size.
We chose to use AWG 1/0 EXRAD XLE 1000 Volt copper cable within the ESS due to its flexibility, ruggedness
and low weight. According to the ampacity table in the data sheet, the 1/0 cable is rated up to 339 amps
(rms), which is well above the 110 A rms current of the pack from our simulations. The reasoning for using 1/0
instead of a smaller gauge cable is to both keep the cable’s expected voltage drop below 5% and to keep the
cable’s expected steady state temperature change under 15 °C. We also selected the 1/0 cable because the
RTM can see power surges of 426.5 amps for approximately 5 seconds based on our drive cycle simulations.
The cable sizes listed in Table 13 were selected by carefully considering peak and continuous current ratings,
and voltage rating.
40
Table 13. Cable gauge selection
The five bus bars in the ESS were sized based off the NEC equation
where is the current in amps and
is the cross-sectional area in square inches. Using our simulated pack
rms current of 128 A, we calculated our bus bar dimensions to be 21mm x 3.9mm.
41
B - Bibliography
J2841. (2005). Society of Automotive Engineers.
Administration, E. I. (2009, April). Retrieved from Washington
http://www.eia.gov/cneaf/electricity/st_profiles/washington.html
State
Electricity
Profile:
Argonne National Laboratory. (2011). Non-Year-Specific Rules. Chicago.
Argonne National Labs. (2011). Emissions and Energy Consumption Deep Dive Presentation. Detroit.
Arnett, M., Rizzoni, G., Heydinger, G. J., & Guenther, D. A. (2008). Implementationof an Electric All-Wheel
Drive (eAWD) System. Detroit, MI: SAE International.
Boyd, S. J. (2006). Huybrid Vehicle Control Strategy Based on Power Loss Calculations. Blacksburg, Virginia.
Choi, S. (2000, March). A Sliding Mode Control of a Full-Car Electroheological Suspension System Via Hard-inthe-Loop
Simulation.
Retrieved
2012,
from
http://scitation.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=JDSMAA000122000001000114
000001&idtype=cvips&prog=normal
Demirbas, A. (2008). Progress and Recent Trends in Biodiesel Fuels. Trabzon, Turkey: Sila Science.
Electromagnetic
Compatibility.
(n.d.).
Retrieved
http://en.wikipedia.org/wiki/Electromagnetic_compatibility
from
Wikipedia:
Freyermuth, V., Fallas, E., & Rosseau, A. (2007). Comparison of Powertrain Configuration for Plug-in HEVs from
a Fuel Economy Perspective. Argonne National Laboratory.
Green Energy Network. (2006). Backgrounder on Flexible fuel Vehicles and E85. Sebastopol, CA.
Jayabalan, R., & Emadi, A. (2003). 24 V Integrated Starte/Alternator Systems. SAE World Congress.
Lynn Gantt, J. C. (2009). Design and Development Process for a Range Extended E85 Split Parallel Architecture
Hybrid Electric Vehicle. SAE International, 1-20.
Mathews, J. C., Walp, K. J., & Molen, G. (2006). Development and Implementation of a Control System for a
Parallel Hybrid Powertrain. VPPC. United States: IEEE.
Mehr, D. K., Michalak, M., Erlien, S., & Bower, G. R. (2009). Optimization and Testing of a Through the Road
Parallel, Hybrid-Electric, Crossover Sports Utility Vehicle. Detroit, MI: SAE International.
Rassem, H., Lequesne, B., Chen, S., Ronning, J., & Xue, Y. (2001). Belt-Driven Starter-Generator for Future 42Volt Systems. SAE World Congress.
Webster, L. (2008, August). How Does Car and Driver Test Cars? Retrieved September 29, 2011, from Car and
Driver: http://www.caranddriver.com/features/08q3/how_does_c_d_test_cars_-info
42
43
C - Appendix
C.1 - Component Sourcing
C.1.1 - Remy Letter of Support
44
C.1.2 - Rinehart Motion Systems Letter of Support
45
C.1.3 - GKN Letter of Support
46
C.1.4 - UQM Letter of Support
47
C.2 - Fuel Selection Matrix Assumptions
Engine Efficiency
For each of the fuel selection categories, engine efficiency was taken into account for each score. E10/E85 has
lower total engine efficiency then B20 engines. The higher efficiency of the B20 engines (about 2%) is due to
high compression ratio which gives engine a better thermal efficiency then E10/E85 engines. Higher scores are
given to engines with better efficiency; highest score is normalized to 5 in each category.
Range
Range is an important consideration; however, all three fuel types will provide enough range for competition
requirements. E85 and E10 represent a blend between ethanol and petroleum. The B20 is a blend of diesel
derived from soy and petroleum stocks. The diesel engine offers better range on a fixed volume of fuel
because of the slightly higher energy density of fuel, along with higher efficiency. Higher scores are given to
engines with better range (fixed fuel tank volume).
CO2 Emissions
C02 emissions numbers are obtained from the Autonomie simulation results. Results are organized by
examining the C02 emissions per mile. E10 has the highest C02 emissions, because it has the lowest efficiency
engine and highest blend of petroleum usage. B20 has second highest C0 2 emissions; because of its higher
efficiency it emits less C02 per mile than E10. E85 has the lowest C02 emissions, because it has the lowest
amount of petroleum in its blend. Because the difference between E85 and B20 emissions is negligible, both
were given a normalized score of 5, with E10 receiving a lower score of 4. Higher scores are given to engines
with lower C02 emissions.
Petroleum Usage
E85 has the lowest petroleum usage, because 85% of its mixture comes from corn based ethanol. B20 has the
second lowest usage of petroleum, with the 20% of its mixture coming from algae or soy oils. E10 has the
highest petroleum usage with only 10% of its mixture coming from corn based ethanol. Higher scores are
given to engines with lower petroleum usage.
Engine Weight
E10/E85 engines tend to be weigh less than B20 engines. This weight difference is most likely because of the
higher compression ratios required by the diesel cycle in the B20 engines. The weight difference is mainly
accounted for by extra engine block thickness. For vehicle performance and dynamics it is desirable to have
the lowest weight engine possible. Thus the E10/E85 engines have an advantage over the diesel in this
category. Higher scores are given for lower total engine weight.
48
C.3 - Proposed Architecture Selection Matrix Assumptions
UF-Weighted Total Energy Consumption
All three architectures give varying levels of efficiency. The modeling results from Autonomie are used to rank
the three architectures to provide a final ranking. This number represents the total energy consumption for
Charge-Depleting and Charge-Sustaining ranges. The main difference in total energy consumption will come
from how efficient each architecture is during charge-sustaining mode.
Series hybrid operate in charge sustaining mode by using a petroleum based motor to power a generator,
which then charges the battery pack. This means series hybrids have multiple energy conversions happening,
which may affect efficiency. TTR hybrids operating in charge sustaining mode generate electrical power in two
ways. If the TTR hybrid has a BAS assist, that can be used to generate energy to maintain SOC, the second way
to generate electricity is by regenerative braking through the RTM. Autonomie will allow the University of
Washington to obtain results to compare these three different efficiencies. Highest scores are given for
better efficiency; highest score is normalized to 5 in each category.
Space Claim
Packaging space is at a premium in the mid-sized Chevrolet Malibu. Fitting all of the drive-train components
into the car will present some technical challenges. There must be enough space to fit all of the motors,
engines, batteries and various electronics components into the car. Series allows for movement of the internal
combustion engine so it receives a higher rating than TTR. TTR+BAS requires high voltage routing through the
entire vehicle. Higher scores are given to architectures with simpler space claim needs.
Controls Complexity
Controls complexity addresses the issue of safety and performance control system complexity. All three
architectures present significantly different controls strategy. The series architecture requires control of the
generator and electric motor interdependently to balance the efficiency. The TTR hybrid requires the control
system to blend torque in the front and rear to prevent excess wear/tear on the chassis and other driver-train
components. All three architectures present safety concerns that are currently being investigated; they should
not vary significantly from each other. Higher scores are given to simpler controls difficulty.
Electrical Complexity
Electrical complexity refers to the overall, low voltage and high voltage electrical sub systems. Series
architectures would require two electric motors, one to act as a generator, one to act as a traction motor.
Both motors would require some sort of motor controller/inverter and associated switching circuitry raising
electrical complexity. The series architecture would also require high voltage cabling to be run to both ends of
the car. TTR and TTR+BAS would allow high voltage systems to be placed at one end of the car, preferably at
the rear of the car. The rear traction motor of the TTR option would provide the regenerative capability
needed. TTR+BAS would add a front electrical motor and possibly secondary high voltage battery pack. Higher
scores are given to architectures with lower electrical complexity.
Weight Distribution
Weight distribution between the front and rear axles must comply with the requirements provided in the
rules. Within these limits, the more balanced the distribution, the better. Higher scores are given for better
weight distribution.
49
Overall Weight
Weight will impact overall performance of the car. Lighter cars will have lower energy requirements for
acceleration, and are likely to handle better. Higher scores are given for lower weight.
Acceleration
Acceleration is measured by the architecture’s 0-60 times. The best 0-60 time is normalized to 5, and the other
architectures are given a percentage of that score based on their specific time. Higher scores are given for
faster acceleration times.
Mechanical Complexity
Mechanical complexity refers to the ease to which the specific architectures can actually be mechanically
assembled. This means that it addresses both component sourcing (i.e., if a component is available) or the
complexity of building a needed component. The series hybrid and through the road hybrid present roughly
the same mechanical complexity because they can be built with mostly off the shelf components. TTR requires
two transmissions and two sets of axles, raising the mechanical complexity. Higher scores are given to less
mechanically complex designs.
Cost
Overall cost of each architecture varies with the component count. The series hybrid requires two electric
motors, a fuel based engine, and a differential/transmission to provide power to the ground. The Pre-Parallel
hybrid needs only one electric motor, one fuel based engine and a single transmission/differential unit. The
TTR hybrid will require, one electric motor, one fuel based engine, and two differential/transmission units.
Higher scores are given to architectures with lower cost.
Support
Support is a dual category. Support comes in two forms, monetary/component donation and technical
support. Some companies may be willing to donate components, but unwilling to provide technical support in
the form of service manuals, CAN database and so forth. Higher scores are given to architectures with higher
levels of support.
Experience
Overall team experience influences the architecture selection from the standpoint of mechanical complexity,
or required software programming needed for an ECU re-configuration. If one architecture has an experience
level below 2, it would disqualify that architecture from possible selection. Higher scores are given to
architectures that corresponded with higher levels of previous team experience.
50
C.4 - Technical Assumptions for Controller Selection
Matrix
CAN Channels
The number of CAN channels on the HSV affects how much software and how many physical HSV's must be
present in the vehicle. If a HSV does not have enough physical channels it must be multiplexed in software, or
a second HSV must be used to gateway signals. The dSPACE MicroAutoBox provides 4 independent CAN
channels. The Etas controller provides 3 channels. The Mototron Motohawk provides 2 channels. Higher
scores are given to controllers with more CAN channels, with the highest score normalized to 5.
Processing Power
The dSPACE and Etas controllers both run PowerPC processors, with the difference being the dSPACE box has
the second generation PowerPC processor, running at 900 MHz vs. the 800 MHz processor in the Etas. Both
the dSPACE and Etas have significantly higher processing power then the Mototron which has a processor
running at 60 MHz. Higher scores are given to higher processing power.
Integration Effort
The HSV controller will be programmed via an interface to MATLAB/Simulink. This means each controller will
require the associated software that can generate code and provide the necessary functionality. Because we
will be using dSPACE software during our HIL testing, some of the software will already be installed. This
means integration with the MicroAutoBox will be simpler than integration with the Mototron or Etas
controller. The Etas system would also most likely require a ECU and HSV to have the proper amount of I/O
functionality, this makes the integration and software effort significantly higher. Higher scores are given to
easier integration efforts.
Cost
Cost affects what controller the team may purchase/obtain. Because all three companies offered a donated
component, this category included the cost for replacement should damage occur to the controller.
Support
Support levels for each controller are dictated by the company that donates each respective controller. If we
obtain a controller from Etas or Mototron we will have a separate tech support contact from our HIL system. If
we choose the dSPACE controller, our dSPACE mentor will be able to provide support along with providing us
with information from others at dSPACE. Higher scores are given to better support scenarios.
IP Rating
Ingress Protection (IP) Rating describes how the controller is rated to withstand harsh environments. Higher IP
ratings are better, starting with IP66-68. Higher scores are given to higher IP ratings.
Table 14. Bibliography and Appendices Revision Log
Date
11/3/2011
12/7/2011
Revision
Section
All
E4
Change Description
Initial Release
Added Section E4 for report 4
51
Responsible
Member
Trevor Fayer
Kerwin Loukusa
C.5 - ESS Design Project Plan
52
C.6 - ESS Fuse Data
53

Year 1: Design Report - University of Washington

Transcription

Similar documents

THIS WEEK ON NET TV THIS WEEK ON NET TV

ModelMCV - Goldberg Systems GmbH

u-rxtm insert

THIS WEEK ON NET TV THIS WEEK ON NET TV

u-rxtm insert

Upsonic Domestic SME Brochure

OfficePower 585AVR

LIFEPAK 500 Maintenance Checklist

KGOT Maps 5 to 6

Rail Road FinalApproved NoLogo 13-11