For reasonable performance about 20 hp must be delivered to the drive train.
Efficiency of energy delivery from batteries to drive train is about 40%
- Delivered energy = 40% of stored energy
- So you need 30 KWH/0.4 = 75 KWH of stored energy
- Energy storage density of lead-acid batteries is .04 KWH per kilograms
- So you need 75/.04 = 1875 = 4125 pounds of lead-acid batteries
- Power: 20 hp/0.4 = 37.3 KW
- Power density of lead-acid batteris is .07 W/kg
- So you need 37.3/.07 = 533 = 1172 pounds
So the range requirements are more severe than the power requirements.
Improvements in battery Technology are definitely required.
- Other types of batteries
- Nickel Iron ED = 55 PD = 100
- Sodium Sulfur ED = 90 PD = 100 (300-350 C operating temp)
- Lithium-Iron sulfide ED = 100 PD = > 100 (400-450 C)
- Nickel-Zinc ED = 75 PD = 120 (low cycle life)
Driving Habits and Requirements
- Long distances - Interstate --> 75 mph and 400 miles range
- Daily Commute --> 55 mph and 35 miles range
- Puttering around town --> 35 mph and 20 miles range
Most practical application is for in town commutting/shopping and this would then eliminate a major source of air pollution
The Key of course is marketing --> people have to buy the product
- Performance
- Range
- Price
- Safety
California Mandate:
- 1998: 2% of all vehicles offered for sale must be zero emission vehicles (meaning electric cars)
- 2003: 10% must be zero emission
Some Prototypes:
- Ford Ecostar two-passenger electric mini-van used by Post-Office and UPS --> sodium-sulfur batteries
- Chrysler TEVan --> nickel-iron batteries
- $500,000 given to Yosemite to replace diesel buses with electric buses
- $500,000 given to General Motors to loan 50 vehicles to 1000 people nationwide for test drive results
Components of Government Program
Comprehensive Reference on Electric Vehicles
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