Enlarge / An automobile chassis sits on display inside a Tesla Motors Inc. store in Munich, Germany, on Monday, March 30, 2015. (credit: Krisztian Bocsi/Bloomberg via Getty Images)

In a Tuesday interview with Bloomberg, the head of Panasonic’s Automotive Division said that the company was on track to complete an additional three battery-cell production lines at Tesla’s Nevada Gigafactory before the end of this year. That puts the expansion ahead of schedule for completion.

Panasonic is a joint owner of the Gigafactory. The company provides the “2170” battery cells that go into a Model 3 battery pack. Tesla packages those cells to complete the pack.

In the interview, Panasonic automotive executive Yoshio Ito told Bloomberg that “the bottleneck for Model 3 production has been our batteries.”