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Sumitomo considering marketing new lower-temperature molten-salt electrolyte battery to automakers for EVs and hybrids

sumitomo
Construction of the molten-salt electrolyte battery. Source: Sumitomo. Click to enlarge.

Sumitomo Electric Industries Ltd. is considering targeting its lower-temperature molten-salt electrolyte battery, being developed in partnership with Kyoto University (earlier post), to makers of electric and hybrid passenger cars, according to Bloomberg.

Sumitomo had earlier said that it intended to commercialize the battery around 2015 for commercial-vehicle fleet operators and stationary applications, and was targeting revenue of more than ¥1 trillion (US$13 billion) from it.

Being non-volatile and non-flammable, and with high ion concentrations, molten salt makes an excellent battery electrolyte and can offer high energy and power densities; Sumitomo earlier reported that it has achieved energy densities as high as 290 Wh/L with the new battery. A drawback to the general class of molten salt batteries (e.g., the ZEBRA battery, or GE’s Durathon sodium-metal halide batteries, earlier post) has been the need for high operating temperatures to keep the salt molten.

In a joint project with Kyoto University, Sumitomo developed a molten salt with a melting point as low as 57 °C. Using this salt, it developed the new molten-salt electrolyte battery.

Since it comprises only nonflammable materials, the new battery will not ignite on contact with air from outside, nor is there thermal runaway from overcharging or temperature rises in the battery. For this reason, Sumitomo says, there is no need for waste-heat storage or fire- and explosion-proof equipment, so the batteries can be packed close together.

The company earlier reported that based on its trial calculations, assuming equal capacity, the new battery had half the volume of lithium-ion batteries and one quarter that of sodium-sulfur batteries, enabling miniaturization.

Sumitomo is continuing work on the battery to find molten salt that can be used at still lower temperatures.

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Comments

Treehugger

could be a breakthrough, maintening the temperature of the cell at 57C might not always be easy but possible

kelly

"The company earlier reported that based on its trial calculations, assuming equal capacity, the new battery had half the volume of lithium-ion batteries and one quarter that of sodium-sulfur batteries, enabling miniaturization.

Sumitomo is continuing work on the battery to find molten salt that can be used at still lower temperatures." sounds encouraging.

DaveD

This sounds VERY encouraging. I'm still waiting to see figures for power density and specific energy (Wh/kg) as they only talk about energy density which is technically Wh/l.

It always worries me when a battery maker throws out a couple of good numbers and then mumbles something un-intelligible about the other specs. Usually means they have some problems to overcome in those areas and they don't want to talk about them.

It would still be great to have a battery "half the size of a lithium battery" but will it weigh as much as a city bus and take a battery as large as a city bus to give you 100kW of power???

I hate to be cynical but I want this to be great so bad that I'd rather know any bad news now rather than get my hopes up and be disappointed later.

Molten salt batteries are usually good for cycle life but terrible for power density. Of course, the power density can be solved with a 10 kg of A123 batteries or supercaps to bolster the power and use the molten salt batteries as the main "energy store". :-)

joewilder

Yes, I'd like to hear more information about this. They might as well include all the parameters.

3PeaceSweet

Hot water is normally stored around 60 degrees C so you could have a pretty useful combined system of hot water and battery storage, an ideal mix for using solar thermal and PV.

ToppaTom

Better batteries, of all kinds, ARE coming.

Advances on many fronts - many synergistic.

Nick Lyons

Looks really promising. The source article (annual report) says they are looking at stationary applications as well as trucks and buses. These might be a great application for off-grid solar storage.

Reel$$

Excellent. With a small trickle charge the battery pack could be kept at temp - except for long periods of no use. Henry G has long touted the ZEBRA, but the tests of those showed them hard to keep at temp (200C) and very heavy.

This new salt sounds like it could solve both issues with ZEBRAs...

HarveyD

The major difference seems to be lower (+58 C) operation temp instead of (+250 C). Another advantage would be much lower cost, claimed to be 1/10 of Lithium batteries.

The claimed volumetric energy density of 290 Wh/L is within the normal range of 170 to 345 Wh/L for that type of unit. The gravimetric energy density, at the cell level could be around 170 Wh/Kg and about 115 Wh/Kg at the battery level.

Specific power is normally rather low at 250 W/Kg.

Combined with super-caps it could work for 30+ years (in heavy vehicles where the extra weight is not so important??)

Engineer-Poet

So much potential, so few products.

Herm

energy density is not too important for stationary applications.

joe.vanni

Excellent battery.
From now until 2015, the year of the sale of this battery there will be other technologies to compete, as Lithium or metal-air, anodes to Graphene etc., new super capacitors, better hydrogen's storage system, and others tecnologies we cannot imagine now.
The road is still long. Hurry up and check it out!

HarveyD

joe...well said. The world will be flooded with many new and/or improved battery-super.cap-FC technologies by the end of the current or next decade. Energy storage and production technologies could take giant steps in the next 20 years. The movement has started and it will not stop.

twitter.com/siromega

This would be fantastic for grid storage applications. There has been a lot of talk the last few weeks about how wind will be cheaper than coal and natural gas in the next few years, and solar will be cheaper before 2020. But how to we make those sources useful? Using these batteries to level out the power generation would help make this better.

Plus grid storage doesn't worry about higher temperatures, density or weight issues. If it takes a bus-sized device to deliver 100kW, as long as it can store enough power for 5 hours, it'll be fine.

DaveD

Good point siromega. Frankly, the strong suit for a battery like this would be grid storage. At that price point, it would be a dream come true for load balancing for solar and wind.

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