Tesla entered an agreement to acquire Maxwell Technologies in a stock swap. That company is known for its ultracapacitors and associated products, but it also has a dry electrode with energy density said to be over 300 Wh/kg, and a potential to hit a density of 500 Wh/kg. I suspect they bought the company for this latter technology to use in a solid-state cell. If they just wanted ultracapacitors, it could have bought the components from them -- no need for a big financial deal. But, by buying the company, it gains access to those and its manufacturing process for the dry electrodes. This would make the whole situation concerning the Model S and X not switching to the 2170-cell format make more sense. If, instead, the Model S and Model X get a cobalt-free solid-state battery with a third better energy density in the next couple years, that would be pretty big. Of course, this is speculation on my part and I could very well be wrong, so I welcome other takes on this deal.