Good idea, thought about it and there are some issues.
Maintenance, who is going to maintain the batteries?
Making sure they have no memory effect. How would you charge for half charge or full charge. People does fuel up with any range on their tanks.
How you know that you have a good battery? 50 miles down the road?
Given to the amount of swapping, how long the batteries will last without deteriorating and if so, how you will dispose them?
That idea can work if you own a fleet and you do your own service.
Electric Motors are the best; bottomless torque and small. The problem is the delivery and the EV1 was a great car for its time. The battery cannot be build; is patent held by an oil company. Just Google this name Stanford R. Ovshinsky, you will be surprised what you will find.
Oil prices are high enough to piss you off but low enough to discourage any other alternatives. All this Hybrid cars are more Gimmicky than what they are worth. Overpriced with a very low return of investment for the owner. Even to produce one it has a Manufacturing Carbon Footprint larger than installing a box over a Suburban Chassis and call it a Hummer H2. But Tree Hugers refuse to see that. If you want a low consumption car a VW TDI is the best approach. For been a Diesel, Bio Fuels can be used. They are Biodegradable and renewable. Biodiesel can be made even from Algae which has a higher yield of Vegetable Oil compared to Coconut Tree oil which is the 2nd best. On Diesel engines they burn completely but sometimes Soot comes out. Just for the simple fact that you can see the soot is not more polluting than gasoline engines. Diesel produce a particulate that is not more than the carbon particulate from a home chimney. Gasoline produce more toxic pollutant but since they are colorless/odorless people assume is less toxic.
