That's how a power wall works. They are made up of thousands of 18650 cells. The problem is charge balancing. When you have a pack with thousands of different c

That's how a power wall works. They are made up of thousands of 18650 cells. The problem is charge balancing. When you have a pack with thousands of different cells from different origins with different internal resistances, keeping the charges balanced becomes a really tricky thing to do.