Recharge your EV's batteries halfway in three minutes?

[wtmusic]

"The Nikkei Japanese subscription news service reports today that Yokohama-based JFE Engineering Corp. has developed a charging system that can recharge an electric car's batteries halfway in three minutes.

The system, which is scheduled to go on sale later this year, works about five times as fast as existing products and will cost 6 million yen ($63,380), or 40 percent less than existing products, to install.

More convenient charging is likely to help electric cars catch on. JFE Engineering sees potential demand from gas stations and convenience stores. The JFE Holdings Inc. unit aims for 15 billion yen ($158 million) in annual orders by fiscal 2015."

http://blogs.edmunds.com/greencaradvisor/2010/05/firm-says-its-made-system-that-can-recharge-evs-batteries-halfway-in-3-minutes.html

Taken with a big grain of salt, as all "breakthrough" claims should be, but posted here because it comes from a major Japanese industrial player with $1.5B in assets.

[hobbit709]

1. But how long to charge the remaining half? That is the question.

[wtmusic]

2. 80% in 15 minutes

and probably a full charge in under an hour.

[Statistical]

3. Better question is how big is the battery pack?

Can it charge 10kWh in 3 minutes? 20kWh in 3 minutes? 30 kWh in 3 minutes?

Half your battery pack is rather arbitrary given that battery packs and thus range vary significantly.

If it can provide for 100 mile range in 3 minutes well that would be huge but without details on current and pack size there is no way to draw that conclusion.

Even cooler is the idea that it draws power from grid at nigh when it is cheap making it available for charge durring high peak times. Could provide a significant retail markup (buy power at 2 cents per kWh sell it at 6 cents = 300% markup). That alone could pay for the unit rather quickly.

[Nederland]

4. That is the question

The bottom line is that residential service entrance circuits range from 125-200 amps. No matter what the battery specs are, you can't put more energy into the battery than you can draw past the main breaker of your home. Once batteries reach a certain size, you will hit that limitation before the limits of the battery's physics. Naturally this isn't the issue with specialized charging facilities that could use 480v, but for residential charging times it is.

[wtmusic]

6. This unit is designed for retail charging (costs $63K). nt

[Nederland]

7. Ok, that explains it (nt)

[wtmusic]

5. There is a somewhat confusing conclusion on AutoBlogGreen

"By utilizing batteries for energy storage, the charger does not rely on super high amperage nor does it require rewiring of existing facilities to function correctly."

http://green.autoblog.com/2010/05/07/new-battery-charger-is-supposedly-really-fast-from-0-to-50-per/

Possibly not super-high amperage going into the charger, but coming out that's a whole lot of electrons, not matter how you slice it.

The other question: how much energy can a charger the size of a gasoline pump store, enough for two or three cars? Something's not adding up.

[Statistical]

8. Yeah lots of unanswered questions but I like any innovation in the space.

Even if the pump was larger you run into cost of batteries limiting capacity. The "pump" will cost about $63K. Say the batteries make up 90% of the cost that is $56K. How large of a battery pack can you buy for $56K? Enough to "fuel" 4 vehicles? 6 vehicles? So if you fuel all of them to 50% that is what 8-12 cars. The maximum number of rechargers per pump per day seems rather low.



The other question is that with a single connector to the car there is a limit on what safe amperage you can push to a battery. You start pushing 10,000 amps in a consumer device and pretty soon someone gets electrocuted (and gas station gets sued).

The other limit on charging is the battery chemistry. lithium-ion batteries can only handle so much current without damage.


One possible explanation is the article says the system requires communication with the car for higher charging. This makes me think the charger is "up to 50% of battery pack in 3 minutes" based on what the car indicates on how fast it can be safely charged.

Still pretty cool idea when you think about it. What good is it for car maker to design "faster charging" batteries if there is no infrastructure to handle it. Essentially this is a publicly available cross brand smart charger. Say a Nissan leaf battery pack can only handle x amphours of current then it tells the charger and is limits flow to that. On the other hand say a Tesla Roadster can handle 1.5x amphours of current then the charger can scale up.

As different battery chemistry hits the market it would be a method for car makers to diferentiate themselves:
"Buy the 2012 Chevy Impulse 80% faster battery charging. Get 100 mile charge in 5 minutes."

The interesting physics challenge is to make something that replicates the high energy transfer rate of gasoline. Gasoline contains 115,000 BTU per gallon. If my conversion is right that is roughly 34kWh per gallon. Say average pump is 3 gallons per minute that is ~100 kWh per minute transfer rate which is a phenomenal amount of energy flow.