Tesla has been on a roll over the last couple of years, proving critics wrong and selling a shit ton of electric cars. They're going to start selling a lot more: They made a deal with battery supplier Panasonic for two billion more cells over the next four years.
Tesla's original deal was for enough batteries to build 80,000 cars. That's 560,000 cells, based on Tesla using 7,000 cells per car.
Two billion more cells will nearly quadruple Tesla's production capacity, which is good because the Model S is soon to be joined by the Model X, as well as a possible all-wheel drive Model S and a rumored smaller model with less range. These two billion batteries should be enough to usher Tesla into its next generation of cars with no issues.