Electric Cars
Transcription
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 EV 2 Automotive History EV 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 3 Automotive History (cont'd) 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 1996 General Motors Saturn EV1 is released 1997 Toyota introduces the Prius, the first mass-produced hybrid 2003 General Motors announces that it will not renew leases on the EV1 2007 General Motors unveils the Chevrolet Volt concept car 2008 Tesla Motors begins production of the Tesla Roadster 2010 100% electric Nissan Leaf becomes commercially available EV 4 1998 Saturn EV1 EV 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) 5 Saturn EV1 today EV 6 2011 Nissan Leaf EV 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)* 7 How far do you need to go? >75% of population drive <40 miles/day! EV 8 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 EV 9 85 90 95 Charging on the “grid” EV 10 Hybrid vs Electric EV Two types of hybrid vehicles (HEV) – Parallel (e.g. Prius) – Serial (e.g. Volt) Pure Electric (BEV) vehicles have no internal combustion engine (ICE) 11 Regenerative Brakes EV Unique to HEVs/BEVs Extend range with little or no effort on the part of the driver 12 Why Lithium (LiOn) batteries? • State of Charge (SOC%) = “gas gauge” • Higher capacity • Excellent shelf life (months) EV 13 Role of Battery Management Systems (BMS) EV 14 Importance of discharge rates "C" rate is time to total discharge (e.g. 1 hour = 1.0C, 5 hours = .2C) Hybrid (HEV) and pure electric (BEV) battery packs are managed differently EV – 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) 15 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. EV 16 Petroleum consumption (Millions of Barrels per Day) 100 90 80 70 60 US World 50 40 30 20 10 0 1980 EV 1985 1990 1995 2000 2005 2010 17 U.S. retail gas prices EV 18 Global carbon (CO2) emissions EV 19 Regional carbon (CO2) emissions EV 20 Future problem EV 21 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 Gas standard items+tires+ brakes $7218 Electric Tires+ brakes $1562 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 22 Why I own an electric car “Fuel” costs for the Nissan LEAF: Assume I get 100 miles per full charge of the car The battery pack is 24kWh; I pay 10 cents per kWh at my house So to go that 100 miles, it costs $2.40 to charge the 24kWh battery Let's compare this to my Ford Expedition: Assume I get 12.5 mpg, so to go 100 miles would take about 8 gallons 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! EV 23 Q&A