wilber1 wrote:
Dang physics.
Energy density of lithium ion battery 0.37 to 0.95 MJ/kg
Energy density of gasoline 44.0 MJ/kg
gas engine efficiency about 25% at best during a drive cycle. electric motors in the high 90-95 %. + the energy recovered during braking.
so that turns tables to about 5 or 10:1 on a weight basis. still and advantage to a gas engine, but not as dramatic as it first seems.
Key is
1) getting charging tine down to about time to fill a gas car 10-15minutes
2) getting infrastructure to support the charging
3) getting power from non hydrocarbon or carbon sources (coal, NG)_ Thermal efficiency of gas turbine power stations is about 60%, better than internal combustion but still not great.
