# Electric Vehicle Battary Exchange

1. May 15, 2009

### mheslep

[Copied out of Russ's "Fix the Energy Crisis..." sticky]

Following up on my https://www.physicsforums.com/showpost.php?p=2188288&postcount=332"on the Project Better Place scheme of buy-the-car-not-the-battery: they claim that they can operate at the same cost per mile as petro power cars at $50/bbl. Better Place's stated vehicle range is 100mi (161km) and they propose battery exchange stations that the car owner can use anytime, all paid for on a subscription per mile plan (ala cell phones). Tesla and other EVs use about http://en.wikipedia.org/wiki/File:Graph_Evolution_of_Tesla_Roadster_Efficiency.PNG" [Broken] at about$600/kWh of Li-Ion battery capacity that should last 100k miles. Better Place's exchange stations must maintain some battery stock, assume 30% stock beyond the batteries on the road. The battery cost per vehicle is then: 161km x 17kwh/100km x 1.3 x $600/kWh-LiIon =$21.2k/vehicle or $0.21/mile. The electric energy cost at$0.09/kWh is $0.025/mile. Total battery and energy cost:$0.23 / mile.

Fuel cost for petroleum vehicles assuming 25mpg and $2.20/gal is$0.09/mile.

Thus just considering batteries and energy, Better Place EVs have a $0.15/mile higher cost than petro vehicles. This is based on the assumptions on vehicle battery capacity, exchange station stock, battery unit price, and battery lifetime - all of which may substantially change. Another factor is the drive train cost difference. The planned Rennault-Nissan 5-seat sedan EV drive train may eventually cost, say,$5k-$7k less than a comparable petro vehicle drive train. Given that Better Place is tightly connected to the vehicle 'alliance', this cost savings could be factored into the per-mile plan. For a vehicle road life of 120k miles, that is$0.04 to $0.06 per mile added to the petro vehicle side of the comparison. Summary: Even accounting for a less expensive drive train, the Better Place EV still costs at least ~55% more per mile. Break even with petrol. cars then requires a similar reduction in the price of batteries (to ~$300/kWh), or an increase in their lifetimes (to 160k miles), or an increase in the price per gallon of gasoline (to ~\$3.5/gal or more if fuel efficiencies increase in mpg), or some combination of these.

Here's a video of a demonstration at an BP exchange station, ~2minute exchange time:
http://www.betterplace.com/company/video-detail/better-place-battery-switch-technology-demonstration/ [Broken]

Last edited by a moderator: May 4, 2017