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Robocars and battery swap?

Update: When I first wrote this, I was under the mistaken belief that Better Place only swapped one type of battery module. At present they only support one, but their swap stations are designed to support up to six kinds, as long as they can be loaded and unloaded from below.

Recently, electric car battery-swap company Better Place announced delivery of their first cars in Israel. Israel is a country of small size where it makes sense to deploy a technology like this with a chicken and egg problem. They hope to have enough battery swap stations that people feel they can drive an electric car and refuel it as quickly and conveniently as a gasoline buggy.

I remain skeptical about battery swap for electric cars, but think robocars solve many of those problems. Here's why:

To have a workable battery swap system, you need to standardize the battery module, ideally having just one or two form factors and electrical characteristics. Just one to start, in fact. This has many downsides:

  • A large part of the innovation in electric cars today is in the batteries. A big part of what Tesla did was their new cooling system. Designers all want to be able to play with chemistries, voltage, controllers and more. They might give up playing with size and placement but not those things.
  • It's still an issue to not be able to vary size and shape of the battery, at least for people wanting to build cars of unusual shape.
  • A large part of the cost of an electric car today is the battery. With the swap system, you can't buy the battery with the car. You get whatever battery you are swapped. That's good in some ways, but eliminates open market competition on these systems because there is only one buyer -- the swap company.
  • Swap machines are expensive, take land and still take five minutes, arrival to departure. That's almost as quick as filling up with gas, but a typical gas station has 8 pumps, and some have many more. If there are several cars in line at a single swap station, you're in for a serious wait.

On the plus side, people actually need swaps more rarely than they imagine. A 70-100 mile range car will hardly ever feel the need for a swap -- in many ways the availability of the swap makes you feel more comfortable about the car, even if you rarely use it. It's better than the level 3 charge which can damage the battery and still takes 15-20 minutes.

I think robocars (cars able to move while empty to the swap station) solve many of these problems. They solve them because while robocars (particularly those operating as taxis) need to run all day and thus want to swap batteries, the cars can move to the swap station on their own, when they are not serving somebody.

  • There is much less need to standardize, though it does help. Your car simply goes to a swap station that has its type of battery available.
  • While it wastes energy and a little time, it doesn't bother the robot to have to go a few miles to find such a station. You don't need one on every popular route.
  • The robot can schedule an appointment for a swap if need be. Not that it really minds waiting a lot, unless it has a job to do. But with a scheduled swap it might even do one while carrying a passenger, if it happens to be passing a swap station and can book a no-wait appointment for the time it will be passing, and the passenger doesn't mind the 3 minute stop.
  • Most typically, this will be used by taxi fleets. Each taxi fleet can have their own swap station, for the type of battery cases they like. They can program their taxis to take jobs that bring them closer to the swap station when they will be running low. You can get buy with just one swap station for the whole fleet, or perhaps just a few. The taxi fleet can have a mixture of cars of different swap types and cars without swap ability. The latter can't run all day and must spend time in charging stations as planned.
  • With robocars, you can solve range problems not by swaping the battery, but by swapping the car. If you have a car that is running low, it can stop in a convenient lot to have you switch quickly to a taxi with lots of charge. Then the car you were in can head off for charge or swap in no paticular rush.

By allowing lots of types of battery form factors and swap stations, you allow innovation and competition in these areas, which in the long run is a win for the customer. Anything that blocks competition may sound good at first but quickly bogs things down.

Now I still want to credit Better Place for working to solve the range and range anxiety problems of electric cars. There will still be competition because I don't expect all electric car vendors to want to be compatible with their system. But I think their technology comes into its own best when the cars can worry about the swap rather than the drivers.

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