Tesla Motors Inc. (NASDAQ:TSLA) and Panasonic Corporation (TYO:6752) announced Wednesday that the Japanese electronics company will supply 1.8 billion lithium-ion battery cells to the Palo Alto-based maker of the Model S luxury sedan and upcoming Model X SUV through 2017, extending their existing relationship.

“This expanded agreement with Panasonic is important to Tesla as we continue to increase the pace of production,” Tesla co-founder and CEO Elon Musk said in a statement announcing the deal. “We look forward to strengthening our relationship with Panasonic, and I’m confident that this partnership will continue to be an integral part of Tesla’s success for years to come.”

Panasonic has been Tesla’s battery supplier since 2011. The cells have gone into Tesla’s Roadster and the Model S luxury sedan released in June 2012. Tesla says customers have logged more than 130 million miles on its cars.

The Model X sport utility vehicle is scheduled to go into production by the end of 2014.