Electric Cars

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Electric Cars
My Electric (Car) Journey
Stanton Zeff, PE
My criteria for owning an EV
(or why it took me 20 years to buy one)
 More than a “2 seater”
 Able to travel at highway speeds (>60 mph)
 Sufficient range (>75 miles)
Leaf was the first EV to meet these 3 criteria
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Automotive History
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1832 Robert Anderson invents a non-rechargeable electric carriage
1835 Thomas Davenport builds the first practical electric vehicle and
receiving a patent for the first electric motor in 1837
1859 French physicist Gaston Planté invents the rechargeable lead-acid
battery
1891 William Morrison of Des Moines, Iowa builds the first successful
electric automobile in the United States
1900 One-third of all cars found on the roads of New York City, Boston, and
Chicago are electric
1908 Henry Ford introduces the gasoline-powered Model T
1912 Charles Kettering invents the electric automobile starter, eliminating
the need for a hand crank starter on gasoline powered vehicles
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Automotive History (cont'd)
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1972 Victor Wouk builds the first full-size hybrid vehicle
1974 Vanguard-Sebring's CitiCar is introduced with a top speed of 30 mph
and a 40 mile range
1975 U.S. Postal Service purchases 350 electric delivery jeeps from AM
General
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1996 General Motors Saturn EV1 is released
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1997 Toyota introduces the Prius, the first mass-produced hybrid
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2003 General Motors announces that it will not renew leases on the EV1
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2007 General Motors unveils the Chevrolet Volt concept car
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2008 Tesla Motors begins production of the Tesla Roadster
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2010 100% electric Nissan Leaf becomes commercially available
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1998 Saturn EV1
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Horsepower: 137
Top Speed: 80 mph (regulated)
Range: 75 to 130 miles
Weight: 3084 lbs
Full charge in 6 hours
$33,995 ($349 per month lease)
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Saturn EV1 today
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2011 Nissan Leaf
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100% electric Zero Emissions Vehicle (ZEV)
Range: 100 miles/charge based on US EPA LA4 city cycle
Top Speed: 90 mph
80 kW AC synchronous motor with 24 kWh lithium-ion battery
Weight: approximately 3500 lbs (including 600 lb battery pack)
Full charge: 7 hrs (240v), 20 hrs (120v), 30 minutes (480v DC)*
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How far do you need to go?
>75% of population drive <40 miles/day!
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How far can you go?
Range vs. Speed (Nissan Leaf)
200.0
175.0
150.0
miles
125.0
100.0
75.0
50.0
25.0
0.0
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
mph
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85
90
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Charging on the “grid”
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Hybrid vs Electric
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Two types of hybrid vehicles (HEV)
–
Parallel (e.g. Prius)
–
Serial (e.g. Volt)
Pure Electric (BEV) vehicles have
no internal combustion engine (ICE)
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Regenerative Brakes
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Unique to HEVs/BEVs
Extend range with little or no
effort on the part of the driver
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Why Lithium (LiOn) batteries?
• State of Charge (SOC%) = “gas gauge”
• Higher capacity
• Excellent shelf life (months)
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Role of Battery Management
Systems (BMS)
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Importance of discharge rates
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"C" rate is time to total discharge (e.g. 1 hour = 1.0C, 5 hours = .2C)
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Hybrid (HEV) and pure electric (BEV) battery packs are managed differently
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BEV have lower discharge rates (<1C) for longer battery life
–
BEV have greater depth of discharge (DOD) for higher capacity
This is why speed directly impacts range (see “range vs. speed” graph)
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Lifetime aging affects
Note: 2 half-cycles = 1 full cycle
According to the U.S. government, LiOn batteries are not an environmental hazard.
"Lithium Ion batteries are classified by the federal government as non-hazardous
waste and are safe for disposal in the normal municipal waste stream," says Kate
Krebs at the National Recycling Coalition. While other types of batteries include
toxic metals such as cadmium, the metals in LiOn batteries--cobalt, copper, nickel
and iron--are considered safe for landfills or incinerators.
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Petroleum consumption
(Millions of Barrels per Day)
100
90
80
70
60
US
World
50
40
30
20
10
0
1980
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1985
1990
1995
2000
2005
2010
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U.S. retail gas prices
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Global carbon (CO2) emissions
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Regional carbon (CO2) emissions
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Future problem
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Cost of owning a car
based on data compiled by Electric Auto Association
for 10yr life (@12k mile/yr) of RAV4 vs RAV4-EV
Maintenance
Items
Lifetime
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Gas
standard
items+tires+
brakes
$7218
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Electric
Tires+ brakes $1562
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Fuel
Costs
Miles
/GGE
$/mile
$/month
Gas
27
$0.139
@$3.75/
gal
$139
Electric
124 (100
mile
range)
$.023
@$0.08/
kWh
$23
EV
Initial purchase price ($20k+ vs.
$30k+)
Maintenance: oil change,
transmission service, radiator
flush, tune-ups
(belts/hoses/plugs), etc., etc., etc.
Fuel/electrons: assume 1 gallon
of gas = 33.53 kWh of electricity
(GGE=gallon of gas equivalent)
$100/month x 120 months = $12,000
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Why I own an electric car
“Fuel” costs for the Nissan LEAF:
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Assume I get 100 miles per full charge of the car
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The battery pack is 24kWh; I pay 10 cents per kWh at my house
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So to go that 100 miles, it costs $2.40 to charge the 24kWh battery
Let's compare this to my Ford Expedition:
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Assume I get 12.5 mpg, so to go 100 miles would take about 8 gallons
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With gas at $4 per gallon, it costs $32 to go 100 miles
For the same 100 miles, LEAF costs ~$2.40 while Expedition costs ~$32
Over the lifetime of ownership, Operational Expenditures
(OpEx) for gasoline powered cars far exceed that of
electric powered cars (by as much as 10:1), eventually
erasing the initial Capital Expenditure (CapEx)
advantage. Eventually, electric cars will reach initial cost
parity...with no trips to the gas station!
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Q&A