@prerunn Said, “… battery cell production isn’t large enough…”
The li-Ion cell production is being scaled up to be mass produced in the gigafactories that Tesla is building right now. The cell production lines are being optimized for maximum production at minimum costs. All of the cells Tesla makes will be used in their products but their Megapacks will be installed in utility scale battery storage projects and their Powerwalls will be installed in tens of thousands of homes.
Tesla is calling their plants gigafactories but they will make more than just giga, they will be making tera quantities. Their gigafactory being built in Austin, TX sits on 2500 acres of land and they have plans to grow 50% per year, year on year. Tesla’s solar and battery storage business will be bigger than the automobile business. You can find out much more information in this YouTube video. You can skip the first hour; the battery info starts at about an hour from the beginning.