All of the new large battery factories that I've seen make the news are being built as joint ventures between a battery company and an automaker for the exclusi

All of the new large battery factories that I've seen make the news are being built as joint ventures between a battery company and an automaker for the exclusive use of the automaker - and the capacity is probably never going to be sufficient for the automaker to sell batteries to 3rd parties. Do you really gain "economies of scale with passenger cars" if you have to build your own battery factory for your long-haul trucks? Which would never be of the same capacity as the automaker factory?