Forgive my brazen armchairing but I question whether it's the right move to go all-in with Li-ion batteries at this time. Both solid state and Aluminium-graphene technologies seem around the corner and are extremely promising.
"around the corner" is the problem. That isn't now. Li-ion is good enough and the tipping point has been reached where we can now have mass adoption of EV's with Li-ion. IMO it's more important to grow the EV market share with existing Li-ion batteries than hold off for a future tech which may not arrive. + Growing the EV market will spur further investment in alternative battery tech. bigger market = bigger investments
You seem to suffer from some misunderstanding. Solid state batteries advocated by companies like Solid Power or QuantumScape are lithium ion batteries. In fact the cathode materials made by Northvolt would go 1 to 1 into a QuantumScape battery.
Northvolt has actually acquired a competitor to those above and will compete in the same field (actually lithium metal anodes, not solid state).
The fact is, that even the most advanced company in lithium metal anodes (wrongly called solid state) will not have its product in 100k cars by 2025. In the years from now to then 10s of millions of BEV have to be built, and the supplier to those cars will have made billions.
And even then, all solid state companies combined will likely not produce enough for 100k in 2025 when the production rate of BEV should be running at 10+ million a year.
So it will take many, many years for solid state (li metal tech) to be a real player in the market and 10s of billions will be made by battery suppliers until then.
For them to simply wait 15 years and do nothing would be kind of crazy.
I am no expert either, but I would expect it will take at least ten years to commercialize any new battery technology.
Investments made today into li-ion production would expect to have a return on investment in under ten years, so it makes sense to make such an investment.
Edit: If it were to take less time to commercialize the new chemistry, it would be because it can piggyback off existing techniques. If that were the case, converting existing infra to the new battery chemistry would be possible. So the current investment would likely not be wasted.
