That's a good point about Apple. If they're able to get batteries 10-15% cheaper than they currently can (I'm guessing they already get a large discount through their buying power) it would make it even easier to defend their mobile and tablet positions.
It's also the exact kind of thing that Tim Cook would do.
http://www.reuters.com/article/2014/02/26/us-tesla-battery-p...
And i'll bet that their meetings with Apple were regarding this factory:
http://appleinsider.com/articles/14/02/16/apple-secretly-met...