JAN 13

A little while ago, there was a big competition going on between two lithium-ion battery manufacturers – A123 and LG Chemicals – to win the contract to build batteries for the Chevy Volt. I have to admit, I was rooting for A123. Maybe it’s because I would have rather seen GM invest in a domestic company rather than a foreign one. Maybe it’s because the founders came from MIT – I mean, what geek can resist that?

But I understood that GM needed to make a business decision, and if they felt that buying batteries from A123 would make an inferior Volt, I grudgingly accept. But apparently the main reason that Bob Lutz and GM chose LG over A123 was… that they wanted flat batteries, not cylindrical batteries. A123 makes cylindrical batteries.

Now, I’m clearly not privy to the engineering plans of the Chevy Volt, but… really? Let’s review what “flat” means in this context. For reference, the lithium-ion battery in your laptop contains cylindrical batteries; if you opened it up, you would see a bunch of batteries that look like your standard AA. That’s what A123 is making. The flat batteries that GM apparently wants are different – the battery part actually has a flat shape to it (as pictured above).

Such flat batteries are important when it comes to, say, building an ultra-thin laptop where every fraction of an inch counts. But would it make that much difference in a car? If you are design engineer out there, and you think it would make a difference, feel free to let me know. All I’m saying is that if A123’s devices delivered the same or better quality performance, and they are an American company, I would have gone with them.

Of course, it’s also important to consider the fact that A123, while a big startup, is still a startup. That may have been reason enough for GM to feel hesitant about making this deal. But A123 is a really big startup, and they are already going through the necessary steps to make their company public. They have hundreds of millions in VC money and employ 1700+ people. So it’s not as if GM would have been investing in one guy with an idea – A123 is serious stuff.

Although they missed the boat on the Volt, A123 seems unfazed; they are pretty determined to make electric car batteries one way or another. They just announced plans to open up a huge battery manufacturing plant in Michigan - the first of its kind in the US – but are asking for government loans (on the order of $1 billion or so) to help pay for it. It would be great if they got it, but if I were the government I’m not sure why I’d put so much R&D money in their one basket when a whole bunch of battery scientists just got together at Argonne National Lab to form a battery research coalition… Maybe they can work together.

Via Earth2Tech, Greentech Media

Comments (24)

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Pure, unadorned ignorance
written by jack perkins, January 13, 2009

Nothing like utter ignorance as a basis for an article. Error No1: A123 Systems DOES NOT build batteries in this country. Error No2: A123 Systems has a PARTNERSHIP with GM and the two are developing batteries. Error No 3: LG Chem is, in fact, an American company. Error No 4: Anyone who has seen the battery packs in the Volt and can't figure out why round batteries make no sense needs to do some research, not write columns that are clearly outside of the writer's field of competence. Error No 4. A123 Systems was also partnered with a GERMAN company (not American, as claimed). On the non-fiction side - there is a Volt , a car being built by GM. The article is perfectly accurate on this point.

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Hey Jack Perkins!
written by Nick, January 13, 2009

Relax wise guy. Everyone is not as smart as you. You could have done all those remarks in a much more polite way.

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Errors
written by Clinch, January 13, 2009

Of course you're going to find errors if you don't read the article properly.
1>
Nowhere in the article does it say A123 builds batteries in america.
It is based in america, and will be making batteries in america when it's new facility in Michigan opens (which is mentioned in the article)
2>
The battery related partnership between GM and A123 is what this article is on about. And as the article stated, that partnership is over.
3>LG chem is a Korean company, not an american one.

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...
written by set abominea, January 13, 2009

well from what I can see the whole reason to use the flat battery over the round one is that I can stack the flat ones in the battery box with less air space around them... less air space means more room for battery in turn more power

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Engr perspective
written by solidification, January 13, 2009

Cylinders are very simple to manufacture. They cost less and are easier to make calculations for.

Cylinders also waste a ton of space and it is more difficult to keep them uniformly at efficient temperatures. In addition to wasting space, the open space around the cells lead to issues with structural stability. Stacking flat plates pretty much only have 1 shear plane.

Less space, fewer materials to contain and maintain the cells. This seems like an obvious choice from an engineering standpoint.

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Happy LG customer
written by Alex, January 13, 2009

Besides the logical issues raised in previous comments (less wasted space, better temp regulation), how about the fact that LG is an established company with a reputation for delivering quality products? If you were making a decision that involved spending a lot of money, wouldn't you consider the track records of both companies?

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A123 couldn't figure out prismatic cells
written by Anthony, January 13, 2009

I wonder why A123 couldn't figure out prismatic cells. I mean, if it were really cylinder vs flat, A123 couldn't have redone them in prismatic cells to win the Volt contract?

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Boring!
written by Anton, January 13, 2009

Please write about the technology and not about US national economy, there are already a lot of sources covering that.
/Sweden

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Money
written by afdag, January 13, 2009

Did anayone tried to find out the cost of each battery pack?
Maybe that is the real reason.

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...
written by MIKE HADDON, January 13, 2009

A123 batteries are known for thier high power density... not their energy density. "off the shelf", such as panasonic, LiIon batteries have higher energy density.

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Volume and heat removal
written by Brian M, January 13, 2009

The flat batteries were probably chosen mainly because they are more space efficient. You say that is not important in a car the same way as in a laptop, but you have obviously never been to an automotive design review where people get into intense arguments over millimeters.

Also, it is easier to remove heat from a flat surface than a round one. Smaller volume + better heat removal = better battery pack.

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...
written by Gene, January 13, 2009

Yes, they'll be buying lithium-ion cells from a South Korean company, but the auto battery lab itself will be in Michigan, employing American workers to build the battery packs.

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Redundancy
written by Josh Ashley, January 13, 2009

The flat vs. round is a good argument. It comes down to volume to surface area ratios. The batteries in the Volt will be charging and discharging very often and very quickly, for a battery. The rapid charging and discharging produces a lot of heat, and that heat can be very damaging to the wiring of the battery or even start a fire (see Sony laptops).

Cylinders have a high volume compared to its surface area. This fact makes for low heat dissipation.

Rectangular prisms have a low volume to its surface area. This fact makes for high heat dissipation, especially as they become thinner and wider.

As to why A123 did not switch to making flat cells, it would require them to engineer a whole new production plant. They probably have existing contracts with the round shape, and did not have the time or capital to build a new facility from the ground up. The high volume to surface area also allows for more electricity storing chemical and less casing.

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Flat cells by Apple
written by Tom34, January 14, 2009

Apple showed in it's keynote how they produce flat cells for their new MacBook Pro 17".
http://www.apple.com/macbookpr...ml#battery

See U.
TOM.

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Circle in a square world
written by Twist9, January 14, 2009

I must say that I am a Chevy sympathizer on this one. The reason is simple, when you are using more than one battery in a bank circular batteries waste space. Now, it might not seem like that big a deal in a car the size of a volt, but the truth is as far as safety and maintenance go flat is miles ahead. Using flat stacks of batteries means that they can be easily put into high-density banks and the excess space can be used for say, sheet insulation and high-durability framework to prevent the batteries from leaking in the event of a crash. It is about time the market realized that round really doesn't make much sense for a battery; I just wish that A123 had understood this and invested in making their products flat.

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A123 Has a prismatic cell
written by G, January 14, 2009

A123 developed a prismatic cell for the volt competition. A picture of it can be found at

http://gm-volt.com/2007/12/03/a123-unveils-new-e-rev-battery-cell-for-chevy-volt/

It is under the plexiglas cover. There are better pictures of it on the web but I couldn't find one quickly.

There are many good technical, cost, and maturity of design reasons why GM could have chosen LG over A123.

My hope is that this is just the first round for A123.

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sohbet, chat, muhabbet,
written by bizimlesohbet, January 15, 2009

nice site thenk you

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...
written by kurtm, January 15, 2009

and if bottoms are placed at the same elevation, the flat batteries have a lower center of gravity. a major plus in automobiles.

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Superior asian technology
written by Atum, January 18, 2009

It is simply a case of the Koreans designing smarter than the US. Nothing unusual here.

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...
written by Corwin, January 21, 2009

As others have said, packing cylinders in an array wastes lots of space. Take a bunch of AA batteries and try and group them as tightly together as you can - you still see lots of daylight between them. While that space could be used to cool the batteries, I suppose, it's not going to be great structurally. If you have flat cells, no wasted airspace, and if you need to cool them, you can pull cooling heatpipes between the cells. All in all, I can see why you would want flat, all other things being equal.

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...
written by Andrew Young, January 22, 2009

A reason they would have wanted flat over cylindrical is packaging! Every inch in a car is just as important as every inch in a thin laptop.Wasted space is wasted material which drives up cost.

Also, you can stack a lot more thin batteries in a given volume than cylindrical batteries, thus giving the car a greater range.

There are lots of other reasons GM could have gone with LG. Price, product specs, reliability, availability of the product, packaging etc.

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Laminar Design vs Round
written by TAG Laugier, January 23, 2009

The potential for improving on the current LG chem laminar stack design is huge. We have barely scratched the surface on the transfer of our vastly superior US developed chip manufacturing technology to the design and manufacture of "stacked" "layered" laminar batteries like the LG prototypes selected by GM.

The "barriers to entry" for this technology have largely been broken by the proliferation and gradual obsolescence of chip (photoresist/solicon based) making equipment. Equipment that is no longer "state of the art" for chips is actually quite good for MEMS and the "layers" that can become our next generation batteries, with integrated power management and control circuitry.

Smart batteries,with integrated recharging, regulating and power management circuits - that is where we need to go. It is tragic to see us spend so much attention to the design and development of smart/robotic systems while we still depend on "stone age" power technology.

Hopefully part of the R&D money promised by the new administration for green technology will be used for the design, testing and manufacture of "quantum leap" technologies for power generation, regulation and distribution.

Science, science, science.... fund it, use it, benefit from it.

TAG Laugier

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written by S Baker, February 04, 2009

I agree, but how many of you posters would pick a Japanese Hybrid over one from Ford or GM?

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written by Fred, July 16, 2009

amazing batteries are getting smaller and smaller

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