To at least satisfy all of the "fire" comments, what if you designed a Powerwall with many interchangeable batteries? Like a street light, instead of having a massive bulb that is expensive to repair/replace, hundreds of tiny little lights that are cheap and the repair/replace of a single failed unit is not as detrimental.
Could the home battery then be formed in a similar manner to this article, without the scary "fire" danger?
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.
Could the home battery then be formed in a similar manner to this article, without the scary "fire" danger?