RogerBW's Blog

I have an idea for a relatively simple change which would remove some of my objections to the use of electric cars. This is less blatantly utopian than the last one.

The basic problem as I see it is that batteries have a distinctly limited life, and are such a large proportion of the cost of the car that electric cars depreciate rather faster than internal-combustion ones. A secondary problem is that, while ranges are getting longer, recharging still takes a long time.

So I want modular batteries. These should be as large as a driver can be expected to haul around, to minimise the number of discrete things that need to be shifted (and to cut down on wasted space and weight in battery casings, though they don't need to be crash-worthy outside the car's frame).

You don't own a battery set for your electric car, in this model. You pay for the right to use one for the life of the car, and this is included in the car's price. Alternatively, you pay a small fixed amount each time you change batteries, which could vastly lower the nominal price of the car. (This would essentially be the cost of the battery divided by the expected lifespan in recharges, plus the cost of the charge itself.)

When the charge in your battery set is getting low, or before you set out on a long trip, you drive to a garage (subtype "filling station"), pull it out, and swap it for a fresh set, which takes only a few minutes, not the hours of charging that the battery itself needs. You get credit against the full charge for the remaining charge in the old set. The garage tops off the old set (from mains electricity and/or any solar panels or windmills they can arrange), and if it's not holding sufficient charge to be sent out again the garage ships it off for recycling.

Obviously you can still charge the battery at home or in a hybrid vehicle, and you could probably arrange with the garage to allow you to take a discharged battery away, charge it yourself, then return it for credit; that would make sense if you had solar or wind generators at home.

When battery tech improves, new batteries can be put into circulation with the same casing and electrical interface.

This obviously requires unified battery interfaces across multiple car manufacturers (one would really want it for vans as well), not to mention redesigns of electric vehicles and a certain loss of efficiency thanks to increased weight of battery casings per vehicle, so it's not going to happen.