Is A123 ahead of Toyota in lithium?

All charged up!

Today A123Systems offered a press release on its partnership with Google to convert a number of hybrid cars into plug-in hybrid vehicles. While the release didn't offer any new details versus Google's press release, it did get me thinking.

Is A123Systems lithium chemistry better than Toyota's?

We know that Toyota is probably going to delay its third generation Prius, at least in regards to the use of lithium. Is this because Toyota has had problems, or is it just because laptop explosions have pushed Toyota into more testing? We just really don't know. Yet, Toyota's lithium-powered hybrids were not going to be plug-ins - a technology which tests lithium even further.

So, is Google taking a risk with its fleet? Is A123Systems hybrid battery technology better than Toyota's? Or, is a small fleet quite different than mass production?