Toyota Motor Corp. and Panasonic Corp. are set to launch a joint venture in 2020 to manufacture batteries for electric vehicles, expecting growing demand in a sector where Chinese and South Korean rivals are gaining ground, sources close to the matter said Sunday.

Toyota plans to take a 51 percent stake in the new company and Panasonic the rest. They will announce the plan as early as this week, the sources said.

The two companies will join forces to develop solid-state batteries, which require advanced technologies to improve the range of EVs while cutting recharging time, they said. Panasonic will shift its five plants for car batteries in Japan and China to the new company.

The venture will supply batteries to Toyota subsidiary Daihatsu Motor Co., Mazda Motor Corp., which has teamed up with Toyota on EV technology, and Subaru Corp. It will also encourage Honda Motor Co. to adopt its batteries, according to the sources.

Toyota and Panasonic announced their partnership on car batteries in 2017 and have jointly invested in a Japanese firm that produces batteries for hybrid vehicles.

Toyota is aiming to sell 1 million electric and fuel cell vehicles in 2030.