Toshiba's SCib Battery

Toshiba announced the commercial release of the SCiB (Super Charge Ion Battery). The battery’s selling points are that it can recharge to 90% capacity in less than five minutes, it’s safe and it has a 10-year lifespan. It can also operate down to -22F. This means that it would apply well to an Electric Vehicle type application, but is a five minute charge feasible for an EV?

One of the major roadblocks to widespread EV adoption is the “gas-up” factor. Consumers want the ability to be able to do a quick recharge when they are on the go. Finally, we have a battery which offers exactly that. It takes about five minutes to fill up a tank, so it could be said that the times are comparable. There is just one little problem with this. Physics.

Let’s use a real production car for an example. Say for instance, we fitted a new Tesla Roadster with SCiB batteries. Could we actually perform a 5 minute charge? The Roadster’s efficiency is reported as 133 Wh/km (4.7 mi/kWh). This means that fully refueling from a 300 mile drive would require around 63kWh of electricity. Multiply by .9 to get a 90% recharge (as Toshiba states is the 5 minute charge) and you have 56.7kWh. Multiply that by 12 to get the amount of kW required for a 5 minute charge. That’s 680kW. Regardless of what you may know about electricity, that’s a whole lot of it.

To actually feed the car 680kW, we need to select a usable voltage. The best that’s commercially available right now would be 480v or actually 220v if it’s household current. For the sake of argument let’s choose 480v. The size of the wire to transfer the energy is dependent on how many amps are going to flow through it. Amps are just watts divided by volts, so when we apply this we get 1416 amps. Technicalities aside, the wire would have to be something like 0/8AWG or about 2 inches in diameter to feed the current to the vehicle. Is this any more or less safe than filling a car with gas yourself? I guess it’s up to the engineers to tell us that.

This battery really is a great thing, but there are serious infrastructure issues to using it. Just one car charging, even for 5 minutes, at 680kW is pulling the same amount of power as 144 homes with air-conditioning on (which is about 40 amps at 110v).

It’s possible to get proper electricity distribution infrastructure in place but it will require massive planning and cooperation between energy companies and energy distributors. The current substations just can’t feed that kind of electricity right now, even for a small number of drivers.

This battery could be successfully used for a 1 or 2 hour quick charge. The numbers work out much better in favor of the existing power grids for that. While it doesn’t necessarily solve the road tripper’s issues of needing a 5-10 minute recharge every 200-300 miles, it will help the majority of EV skeptics in reassuring that a pure EV is fairly capable of delivering extended service without needing a full day of recharge time.

Without a published energy density, it’s difficult to say if these batteries are light and powerful enough for every day EV use. Even so, they are a step in the right direction and could be fantastic for general use once the power grids can deliver the amps. Until then, we will have to depend on the plug-in hybrid to be the duct-tape helping hold the existing gasoline distribution networks together with the electric future.