No, Musk should not refocus on batteries. Here's the thing. The cars he is building are battery-agnostic. If someone produces a breakthrough in battery durability, power density, etc., he doesn't have to change his vehicle designs. With a little engineering, he can plop the new, better batteries right into his cars and keep on producing them. Whereas battery tech is risky. Musk is on top of lithium-ion batteries, but if (or rather, when) someone patents something better and brings it to market, he'll be out of luck if his business is built around lithium-ion batteries. If Musk hopes to keep Tesla going as a long-term proposition, he's much safer sticking with well-engineered cars, and keeping batteries as a sideline that he can jettison later on.