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[NoiseBoy]

http://www.bbc.co.uk/news/technology-26934932

Ok so it's small scale and expensive but it's interesting to see a practical demonstration.

[cloroxbb]

Someday, it will happen... It just may be a very long time.

[kensiko]

I don't find any big issue with the charging time of current Li-Ion batteries. Just look at Tesla quick chargers.

[benswing]

Tesla Model S cars charge at greater than 1C, so why are we limited to 1C?  Is our battery chemistry different?  If so, is 1C a limit or is it something that is probably a good idea but nobody has tried charging faster regularly?

[NoiseBoy]

It's probably a heat management issue. Also charging faster degrades the cells and Zero has a warranty to think about.

[protomech]

Partly it's chemistry and battery durability.

Partly it's cell heating due to charge rates; the Model S uses liquid cooling, our bikes use only passive cooling.

There's certainly room for improving our our battery's charge power, but that only goes so far in typical applications (portable electronics, EVs) .. particularly if it forces other compromises.

It'd be great to charge our 10 kWh bike batteries with 50 kW CHAdeMO (5C) or 135 kW Tesla Supercharger (13.5C .. up to 54C for ZF2..
It'd be great to charge smaller 24 kWh car batteries (Nissan LEAF) with 135 kW Tesla Supercharger (5C).

Charging at substantially higher power than Tesla's Superchargers - 30 second charge is 120C - would almost certainly require onsite battery backup that is then charged at a slower rate by the grid .. and likewise, charging smaller vehicles or portable electronics would require substantially beefier supplies than we're used to.

Charging a 10 Wh cellphone in 30 seconds would require a 1.2 kW supply, like the 2013+ Zero bikes.

Charging a 100 Wh laptop in 30 seconds would require a 12 kW supply, 240V 60A.

There might be some applications for vehicles that run short routes - municipal buses or possibly race EVs on a track. Suppose a 10 kWh vehicle can execute 10 laps. If you could charge it wirelessly - perhaps in a low-speed turn or over inductive pads - then one lap would require only 3 seconds of charging.

Its power characteristics would also work very well for micro hybrids, which need to be able to sink or source large amounts of kinetic power, without regard for absolute energy storage (usually cost and packaging are more of a consideration).

The key with extremely high-power battery technology - like Toshiba SCiB - is whether their intrinsic characteristics as a whole are more attractive than other chemistries. Toshiba SCiB can be charged in 6 minutes - which is about as fast as you'd really want to charge an EV IMO - but it was expensive and low energy density that ultimately killed it in the market.

[Justin Andrews]

There is a few important pieces missing from the story.

What capacity was the battery?
What is its power & energy density?

[Doug S]

The key with extremely high-power battery technology - like Toshiba SCiB - is whether their intrinsic characteristics as a whole are more attractive than other chemistries. Toshiba SCiB can be charged in 6 minutes - which is about as fast as you'd really want to charge an EV IMO - but it was expensive and low energy density that ultimately killed it in the market.

Some AGM batteries do not have a maximum charging/discharging current. There have been some custom-made vehicles/charging stations which could recharge very, very fast -- ten minutes or less for some. Of course, lead-acid (AGM is a variety of lead-acid) is problematic for mainstream vehicles because of its weight.

LiFePO4 is much lighter than AGM, though its power density is about half that of many other Li-ion varieties. But it has some pretty significant advantages: It's cheaper (about a wash kWh to kWh), it's much more tolerant of high temps (some can operate as high as 400-500 degrees C), they have much longer lives (not really known yet but it's thought they can easily do 5000-10,000 cycles), and they have much lower internal impedance so can be charged/discharged much faster. IIRC Mission is using them on their bikes, which is why they think they can do a DC charge VERY fast, provided you can supply the power.

I'm an EE and I've been very happy with the LiFePO4 designs I've done (though only two so far, and much smaller than EVs). To me, the safety aspect alone makes it a very appealing candidate, and I think Mission made a good call.

[Richard230]

The Chinese Hi Power (brand) LiFePo4 cells that I had in my two Electric Motorsport GPR-S bikes sucked.  My last bike had 24-50Ah cells and they died in about 1K miles trying to supply 150 amps occasionally to the D&D Sepex motor.  Some of them puffed up and blew stinky gas into the air and others just decided that they preferred to store 10Ah instead of 50.  In the end, I ended up with 24 useless bricks.

So some LiFePo4 cells are better than others and you can't necessarily depend on just the technology without knowing how the batteries are designed and made at the factory.

P.S.  I have a couple of packages of Hi Power watch batteries that cost an average of 10 cents each.