How many barrels of oil will these batteries save over their life?Tesla Motors and Panasonic inked a deal in 2011 for enough battery cells to build approximately 80,000 cars over 4 years. That's a lot of electric cars, and a lot of batteries, but those numbers look small compared to the new agreement that was just signed. Tesla is already on track to build more than 20,000 Model S electric sedans this year, and that's despite having only recently started to sell them in international markets. Within a few years, they'll not only sell the Model S all around the world and will have many more Supercharger stations everywhere to entice buyers, but they'll also have the Model X as well as their third generation platform that will be much more affordable and produced in larger numbers (no name yet, but it should be in the $30k range). This will require a lot more batteries, hence this new deal.
Panasonic has agreed to supply nearly 2 billion cells over the course of four years. How does that big number break down in term of EVs?"With the largest Tesla pack using around 7000 cells, the quantity involved is enough for close to 300,000 vehicles. Given that sales will grow over time, it seems likely Tesla is preparing to reach 100,000+ vehicles sold in the final year of the agreement — five times the 2013 total." (source)
So a quintupling of production in a few years. Not bad!
And as far as I know, the deal between Tesla and Panasonic isn't exclusive, so Tesla could go to another supplier to get more batteries on top of this.
The batteries are apparently co-developed by Panasonic and Tesla especially for automotive applications:
Together, Panasonic and Tesla have developed a next-generation battery cell technology that provides the highest energy density and best performance cells in the market. Panasonic’s cylindrical cell is a customized technology designed specifically for optimizing electric vehicle quality and life. These cells are integrated by Tesla into the battery pack in a way that enables an industry-leading range of approximately 265 miles for the Model S. (source)