Panasonic is apparently hedging its bet with a different battery design than the cylindrical cells that are jointly manufactured with Tesla.
Toyota and Panasonic are exploring a potential joint production collaboration for batteries used in electrified vehicles.
Panasonic already has a manufacturing partnership with Tesla, though its '2170' cylindrical cells produced in the Nevada Gigafactory are likely being used solely for the Model 3.
The tie-up with Toyota involves a different battery design, known as prismatic cells, which are more popular the mainstream hybrids and EVs built by established automakers.
"The auto industry faces many hurdles to developing next-generation batteries which are difficult for automakers or battery makers to tackle on their own," Toyota president Akio Toyoda said at a media event.
The executive suggests the Japanese automaker faced a significant challenge in meeting its long-term targets without outside help in battery development and production. The company expects to sell 4.5 million mild hybrids and plug-in hybrids by 2030, alongside 1.0 million fuel-cell vehicles and pure battery-powered EVs.