# Battery improvements on horizon



## QuietCar (Jan 3, 2013)

Sorry if this is old news:

March 28, 2014 7:00 pm JST (Japanese Std Time)

*New components help lithium-ion batteries take the heat*




OSAKA -- Technologies coming out of Japan promise to make electric vehicles safer by reducing the chances of battery fires. The innovations should also make the cars more efficient.
Daikin Industries, best known for its air conditioners, and Nippon Kodoshi, a maker of capacitor separators, have each developed ways to improve the heat resistance of electric cars' lithium-ion batteries. This will eliminate the need for a battery-cooling system, cutting power consumption as well as body weight. Single-charge mileage stands to increase by up to 30-40%. 
Daikin created a heat-resistant electrolytic solution and electrode in partnership with Kansai University. The Osaka-based company used fluorine in the solution to reduce flammability; tests have shown batteries made this way function problem-free at temperatures up to 60 C. Since that is how hot car batteries get without the cooling mechanism, the temperature is the industry's target for boosting resistance.
Daikin also adopted other new techniques, including the use of a highly heat-resistant adhesive agent for setting electrodes' metallic materials. The company is eyeing commercialization in 2020.
Nippon Kodoshi, meanwhile, enhanced the heat resistance of electrodes and separators in cooperation with Japan's National Institute of Advanced Industrial Science and Technology. The company created a new separator -- the membrane that keeps electrodes apart but allows the flow of ions -- from finely processed plant fiber. As this material does not shrink, it performs better at high temperatures than conventional separators made with resin film. 
Nippon Kodoshi, too, used a more heat-resistant adhesive agent for the electrodes. The company has begun shipments on a trial basis; it hopes to commercialize the technology in five years.
Lithium-ion batteries produce electricity through a chemical reaction, and this generates heat. Current batteries need to be kept below 45 C -- otherwise, their performance could deteriorate and they may even ignite. Electric cars rely on cooling systems to avoid this, but the systems require a lot of juice, especially in the summer. When a cooler runs at full-bore, mileage can decrease by about 30%.
(Nikkei)


I just thought it to be a tasty tidbit.


QC


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## Karter2 (Nov 17, 2011)

It sounds like they are treating the symptoms , not the root cause !
The correct answer would be to improve the "chemistry" such that it doesnt generate the heat in the first place...that is the real waste of energy. !


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## sunworksco (Sep 8, 2008)

Cold fusion?


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## Karter2 (Nov 17, 2011)

I would settle for just better batteries .
Low IR / high C rate, but used at lower actual discharges such that the heat is not generated.
It can be (is) done currently, but by greatly over sizing the battery capacity, resulting in a weight penalty.


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## rtz (Jul 3, 2013)

In his hands is the next latest and greatest battery(From Calb). Should be available in a couple weeks.










At 40 minutes into the program for the details:






60% of the volume and 80% of the weight.


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## JRP3 (Mar 7, 2008)

Karter2 said:


> It sounds like they are treating the symptoms , not the root cause !
> The correct answer would be to improve the "chemistry" such that it doesnt generate the heat in the first place...that is the real waste of energy. !


That's not really the issue. The cells don't generate much heat at all in normal use. The problem is when they are used in hot climates sitting in the sun all day the car and battery absorbs all that heat.
However, I noticed they didn't say anything about cold weather behavior, and assuming they don't address that with this electrolyte means that active temperature management will still be needed in cold weather.


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## Karter2 (Nov 17, 2011)

JRP3 said:


> That's not really the issue. The cells don't generate much heat at all in normal use. The problem is when they are used in hot climates sitting in the sun all day the car and battery absorbs all that heat.


 Isnt it ?..
I read the OP as being a development to address this..


> ...Lithium-ion batteries produce electricity through a chemical reaction, and this generates heat. Current batteries need to be kept below 45 C -- otherwise, their performance could deteriorate and they may even ignite. Electric cars rely on cooling systems to avoid this, but the systems require a lot of juice, especially in the summer


 If you can prevent cells generating heat internally, then keeping the battery "environment" or enclosure cool is simple and easy using existing proven technology.. IE:- insulation and air conditioning. (which can be solar powered for a contained battery enclosure).
A much bigger issue would be the energy required to maintain a suitable temperature for the vehicle occupants who are much less tolerant of temperature variations than the battery pack is.


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## JRP3 (Mar 7, 2008)

Depends on the chemistry and how hard you're pushing it, but most EV's under normal operation don't generate significant internal heat. The article is simply wrong in that regard. Anyone can measure their pack temperature after a drive and compare it to ambient to see for themselves.


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## Karter2 (Nov 17, 2011)

> ...most EV's under normal operation don't generate significant internal heat


 Well , seems like Tesla and GM (volt etc), amongst others,.. disagree with you on that.
They have put a lot of resources into studying the pack performance and subsequently put a lot of effort into ensuring there are active cooling systems integrated within their packs. I believe some those systems are programed to operate continuously when charging !


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## JRP3 (Mar 7, 2008)

No, it's to keep the pack temperature within range when the vehicle is in extreme temperatures, both hot and cold. If it's not hot, or cold, the temperature management does nothing when charging, other than cool the charger itself. Almost no one bother's to cool the LiFePO4 cells we use in our conversions, and they simply do not get hot during driving or charging. Nissan didn't cool their pack, and only people living in extremely hot climates are having problems. If the cells were self heating during use, every LEAF owner would be having problems, but they aren't.


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