Ah, yes, batteries. It’s the elephant in the room for legacy car companies contemplating a push into the EV market.
There are five major battery suppliers for EVs: Tesla/Panasonic, LG Chem, SK Innovation, CATL, and Samsung SDI. Nissan also manufactures batteries for their Leaf, (Automotive Energy Supply Corporation), but have recently sold that part of their business to Envision.
The largest EV battery producer is Tesla/Panasonic which supplies batteries for Tesla cars. Tesla and Panasonic share a strategic partnership at their Sparks, NV factory (Gigafactory 1), and another in Buffalo, NY (Gigafactory 2). Tesla has plans to build Gigafactory 3 in Nanhui New City (Shanghai, China) by 2020.
The limited supply of EV batteries is a huge problem for traditional auto manufacturers, and will continue to be for several years. That is why EV products announced by Audi, Jaguar, BMW, Mercedes, Porsche, etc. have limited production goals. VW reports having signed agreements with three different battery suppliers (Samsung SDI, LG Chem, and CATL) worth some $48 billion over 5 years, rather than taking the more risky path of building their own battery factories.
It remains to seen how competition in the EV market will play out, but it is fairly clear that companies with the best access to competitively priced batteries will dominate the market. Tesla is years ahead in this race.