Prime Planet Energy & Solutions In December 2017, Toyota Motor Corporation and Panasonic Corporation agreed to start studying the feasibility of a joint automotive prismatic battery business. On 22nd January 2019, Toyota Motor and Panasonic announced that they had signed an agreement to establish a joint venture, Prime Planet, for the automotive prismatic battery business, focusing on R&D, production technology, manufacturing, procurement, orders and management of automotive prismatic lithium-ion batteries, all-solid-state batteries, and next-generation batteries. Prime Planet Energy & Solutions