Panasonic Holdings Corp (6752.T), which makes batteries for Tesla, said on Wednesday it had shipped samples of its more powerful 4680 format electric car battery to the U.S electric vehicle maker as it prepares for a surge in North American power pack production.

Panasonic said mass production of the new battery is set to begin in its new fiscal year starting March next year at its plant in Wakayama in Japan, before production is moved to North America…

The Japanese conglomerate is looking at potential factory sites in Kansas and Oklahoma that would supply the Tesla plant in Texas, two people with knowledge of the plan have said.

The Japanese company already has a factory in Nevada that supplies smaller batteries to Tesla. Production capacity there was recently expanded to 39 gigawatt hours (GWh).