Many car parts are outsourced. Headlights, seats, airbags etc. I don't see how the batteries could be different. It's not like Tesla itself makes cells that are

Many car parts are outsourced. Headlights, seats, airbags etc. I don't see how the batteries could be different. It's not like Tesla itself makes cells that are assembled into batteries in their factories, is it? Even if it does (I honestly don't know, last time I had this discussion about a year ago it had cells made by Panasonic though Panasonic line was located in their factory), Sony, Samsung, LG and aforementioned Panasonic still make these cells and sell to anybody who is willing to buy.