Last week Elon Musk, the iconoclastic CEO of Tesla Motors declared that Tesla would effectively allow any competitor to use its patents portfolio. Shortly after, BMW and Nissan announced that they wanted to cooperate with Tesla on technology and standards. Between them, these three carmakers own almost all the market for electric vehicles and as such are natural competitors. So what motivates this recent cooperation: is it just good PR, is it plain altruism, or is there something more calculated?