From MIT's Technology Review:
GM is playing it safe with its promised electric car, choosing a veteran battery supplier.
There's still no official word (it's expected by the end of the year), but it looks as though A123 Systems, a company based on a remarkable new battery chemistry formulated at MIT, won't be supplying the batteries for the first generation of GM's new electric car, the Volt. The contract, according to a couple of news reports released in recent weeks, will go to LG Chem, a Korean company.
GM had considered A123, a startup with no large-scale experience manufacturing automotive batteries, in part because A123 had developed a novel battery chemistry that produced very powerful, safe, and long-lasting batteries. So, why didn't the company get the contract?
First, some background on why A123 was in the running in the first place. A123 replaced the cobalt-oxide-based electrodes of conventional lithium-ion batteries with new nanostructured iron-phosphate electrodes. These phosphates are inherently safer than the cobalt-oxide-based chemistries, which have been known to suddenly burst into flames, destroying laptops and cell phones in the process and leading to massive recalls. The conventional cobalt materials also don't last very long--that's why laptop batteries have to be replaced every couple of years. The capacity of A123's batteries, in contrast, doesn't fade much with use. Safe, long-lasting batteries are essential in cars, where they're expected to survive abusive conditions for a decade or more. Ultimately, cost is the biggest issue, and A123 has advantages in this area as well. Safer materials ultimately reduce costs by decreasing the need for redundant safety systems (such as those used in the Tesla Roadster). What's more, longer-lasting materials reduce the need to oversize the batteries to make up for fading capacity over their lifetime--something else that reduces costs. Finally, by replacing cobalt with iron, A123 also reduced the cost of materials.
LG Chem uses a manganese-oxide-based electrode, which is less inherently safe than A123's phosphate-based materials. The company uses other modifications to the cells, including a novel separator between the positive and negative electrodes, to make up for this....MORE
HT: Peak Energy