Battery Electric PowerDavid Clark, retired Senior Lecturer,

Mechanical Engineering, Swinburne UniversityEV Expo 13 April 2013, Alternative Energy Association

• Tool Power Cordless Drills• Pedal Power People power• Bike Dynamics Speed, slopes & brakes• Car Power Speed, slopes & brakes• Engine Types Power, efficiency• Motor Types Power, efficiency• Battery Types Energy storage, mass• Choosing systems Bikes, electric, hybrids

Tool Power• Youth in tinnie, cordless drill driving propeller!• Cordless drills Battery• 2003 Metabo $299 12v 16.8Wh 0.65kg NiCd• 2013 Taurus $6024v 31.2Wh 0.85kg NiMH• 2013 18vLi-Ion readily available range• Ozito $78 23.4Wh 1.4kg 2batteries– Bosch $198 27Wh 1.3kg 2batteries– Makita $249 23.4Wh 1.6kg 3batteries– AEG $269 3 year trade warranty

Pedal Power• 80’s Gent keeps riding with his front elec. motor!• Pedal power - 5min 300W, 1hr 200W, 5hr 100W• Sport bike 20km/h 30km/h 40km/h• Speed level 60W 160W 360W• Slope 1% +/- 44W 66W 88W• Slope 2% +/- 88W 132W 176W• Acceln 10sec 121W 40sec 121W• Braking 2sec 600W 4sec 1200W• Solar racer 3kW for about 120km/h

Passenger Car Power• Nissan Leaf keeps up with all cars on green light!• Vehicle assumptions – 2m2 area, 1000kg• Power needs 40km/h 80km/h

120km/h• Sedan 0.3Cd 0.5kW 4kW 13kW• Sports 0.23Cd 0.4kW 3kW 10kW• Slope 5%+/- 5.6kW 11kW 17kW• Slope 10%+/- 11kW 23kW 33kW• Acceln. 15sec 4kW 36kW• Braking 2sec 30kW 4sec 136kW• Combine all power demands together

Vehicle Parameters• Fuel parameters• Engines – 220-230g/kWh, 39-37% efficient• Liquid fuels – 42.5MJ/kg, 11.8kWh/kg• Diesel engines & turbochargers are better!• Battery parameters• Li-ion2<3kW/kg 60<80Wh/kg HEV• Li-ion1<2kW/kg 130>90Wh/kg PHEV• NiMH 1-1.5kW/kg 45Wh/kg• Electric motors take short-term overload!• Very high efficiencies with exotic magnets

Choosing Systems• Bikes Front, crank or rear wheel elec drives• Miev 16kWh, 47kW motor, 155 km range• Leaf 24kWh, 80kW motor, 140+ km range• PriusC 0.9kWh N, 1.5 eng, 45kW mtr, 3.9L• Jazz 0.6kWh N, 1.3 eng, 10kW mtr, 4.5L• Volt 16kWh, 1.4 eng, 111kW mtr, 87km, 4L• VWXL1 5kWh, 0.8 diesel, 21kW mtr, 0.9L• Final decision – people, distance, frequency,

investment, preferences