There are a couple of problems (this is a followup to
@KarenRei's post as well):
- Panasonic 18,650 production is at 10 GWh/year, Panasonic 21,700 cell production is currently at ~28 GWh/year.
- If Tesla doesn't buy the 18,650 cells, what happens to that 10 GWh/year capacity? Panasonic will be free to sell them to other carmakers - many of whom would be happy with competitive, time-proven cells that are enough for either 100,000 100 kWh packs per year or 200,000 50kWh packs per year. Does Tesla want to push Panasonic into doing that, or do they want to make a deal with Panasonic to use that 18,650 capacity? My guess is that Tesla doesn't want to leave that battery supply on the market - which would also come with a matching raw materials drain on the world market (lithium, etc.). So the 'sunk cost fallacy' does not apply at all here - the 18,650 supply is a highly successful product that Tesla shouldn't abandon.
Using 18,650 cells in storage might work - except that Tesla appears to have standardized in 21,700 cells for storage - they are more cost efficient, plus the 21,700 cell manufacturing supply can be flexibly configured to either be for storage or for automotive.
A couple of possibilities:
- Bringing the 18,650 lines from Japan over to China. 10 GWh/year capacity just happens to be enough to make 3,000 Model 3 Standard Range versions per year, and would be a good way to bootstrap battery production in Shanghai. Panasonic's CEO expressed interest in the summer to invest into the Shanghai Gigafactory.
- Bringing the 18,650 lines (and other equipment) from Japan to the U.S. and consolidating all battery production in the Nevada Gigafactory.
- Converting the 18,650 lines to the 21,700 format. It's literally just a dimensional change - albeit it would impact a lot of bits of the production lines. Maybe this is possible - maybe it's too expensive.
- Note that the Shanghai Gigafactory lines, if they come from Japan, could also be converted to 21,700 format, because if the S+X is migrated to 21,700 first there's no disruption to existing production.
In any case, I'd be
very surprised if Panasonic threw away the lines or if Tesla left them for the competition to pick up.
Note that the most important step to move the 18,650 lines would be to migrate the S/X battery pack to 21,700 cells - and the phase-out of the 75 kWh model might be the precursor to that.
