Here's an article with Toyota and Tesla:
Toyota already building EV prototype with Tesla battery pack? — Autoblog
There was a mention of a link between Panasonic and Toyota. As a side note, in my destroying of bad laptop batteries, so far I have found that the batteries labeled "Panasonic" tend to have a voltage (in the 4+ volt range) straight out of the bad battery pack, and only ONE of the batteries in "Panasonic" packs tends to be bad, whereas in packs without a manufacturing tag tend to die in pairs, and even good batteries tend to hover in the 2v range....