If Tesla executes, they are going to be the leading company in a number of industries, of which battery technology and manufacturing is one of them. They are also leaders in direct sales, JIT manufacturing, motor design, any one of which is a disruptive innovation channel they could monetize, all in the service of building electric cars. Tesla is an energy company, a battery company, a car company, etc, just as GE or any other innovator ends up in many segments. What they are is a nascent Multi-business, Multi-national company that the market is betting (based on the stock price) is going to be able to be a global force. A lot of publicly traded companies are single-business companies that derive most of their revenues from a domestic operation. The few companies that manage to become multinationals have this outsized influence because they tend to drive massive revenues, earnings, and markets caps. The correlation between operating in multiple business areas and being a massive multinational is a direct relationship, because disruptive businesses always reach a saturation point. Businesses like Tesla that set out to disrupt industries that represent significant portions of GDP will naturally need to move into multiple markets in order to execute their strategies, because they need to disrupt or create a sequence of disruptive or creative strategies in order to reach that saturation point (natural market size).
I love Elon for the fact that he thinks of his businesses on a planetary basis, and if you consider the point, you'll see he's actually executing Tesla in multiple markets simultaneously, and essentially going directly from startup to Multinational, and skipping the domination of a single category. He knows that if he doesn't, he's going to face stiff competition from entrenched companies and it's likely he'll lose his advantage. But by tight control of the supply line businesses, and a few strategic relationships with existing multinationals, he's able to elevate Tesla into a multi-business, multi-national organization in record time.
Sure, they're a battery company, but what they really are is an organization that's shooting for the moon and actually executing at that scale. Simple incredible to watch.