According to reports, Tesla CEO Elon Musk said that he's not worried about being beaten by other companies on a cost per kWh basis when it comes to batteries. In particular, when pressed about the amazing price point Nissan seems to have attained with the batteries that will go in the LEAF (perhaps even as low as $375 per kWh), Musk reportedly said that Nissan uses a “much more primitive level of technology.”
Musk believes that because Nissan's battery pack is passively air cooled instead of actively liquid cooled—like Tesla's battery packs—the LEAF's battery temperature will be “all over the place,” and result in “huge degradation.” In addition, Musk reportedly believes that the LEAF will not be able to operate in cold environments and will “shut off” in hot environments. In the past, Nissan has said they are extremely confident that the LEAF batteries will perform reasonably well in both hot and cold environments, but that it will likely see a performance reduction to some degree when operating at extremes.
Given that the LEAF has an 8 year/100,000 mile warranty on its battery pack, whereas the Tesla Roadster only has a rather standard 3 year/36,000 mile warranty, I'm not sure if Musk has much to stand on here. Nissan's Mark Perry recently said that their design mantra was to keep the LEAF as simple as possible and that adding in a liquid cooling system would have added significant expense. He also told me that with Nissan's 20 year history of battery design, they felt confident that their battery pack would withstand the daily grind even without the liquid cooling. According to Perry, future generations of the LEAF will have some kind of active cooling, but it will likely still be air driven and not liquid.
Musk and Tesla are in the initial stages of gearing up for production of the Model S, an electric luxury family sedan due in 2012. At nearly $58,000, Musk hopes the S will finally turn Tesla into a profitable company. Musk said that the battery costs for the Model S are on track to be 40% less than for the Roadster. Even so, it's unclear why Musk is picking on the LEAF given that the two companies, for the foreseeable future, won't even be competing in the same category.