In another sign of a strained partnership, Tesla and Panasonic are reportedly ending their joint production of solar cells at Tesla's Gigafactory 2 facility in New York, according to a report in the Nikkei Asian Review.

Tesla and Panasonic formed a joint venture to manufacture solar cells there four years ago. As part of their deal, Panasonic committed to paying for part of the equipment at the plant in Buffalo, New York. They began producing components for solar photovoltaics there in 2017.

While Panasonic-made solar cells were going to be used primarily by Tesla to make its own solar panels, Tesla's current Solar Roof product uses cells made in China instead. According to Nikkei, Panasonic has been selling cells it made at the Buffalo plant to other clients.

Tesla and Panasonic did not immediately reply to requests for further information.

Panasonic is still a main supplier of battery cells to Tesla for its vehicle battery packs, and the two companies jointly occupies a giant plant, called Gigafactory 1, outside of Reno, Nevada. However, Tesla has also been forging ties to battery cell makers CATL in China and LG Chem in South Korea.﻿