Dumb question but I’ve always wondered if we could make a giant reusable “hand warmer” type chemistry around the battery and use that to get it going in cold environments.
Looking into it more. Maybe something like supersaturated solution of sodium acetate (plus water) in a sealed pouch with a metal disc. Bending the disc triggers crystallization, releasing stored heat (around 130–140°F for 20–60 minutes). Boil them to reset.
So you could boil and reset them during charging and click them off if needed in cold weather.
I don't think it's a dumb question at all. Storing thermal energy separately from electrical energy would make plenty of sense if we could store the thermal energy better (cheaper, lighter) than the electrical energy.
A quick search suggests that sodium acetate used like this stores 230kj/kg (i.e. 64 Wh/kg in the units used for batteries) [1] which is significantly worse than the sodium ion batteries being discussed. Same order of magnitude though, so maybe there's a better material that would make it work.
[1] https://www.sciencedirect.com/science/article/abs/pii/S13594...
"Chinese battery giant CATL and automaker Changan Automobile are preparing to put the world’s first passenger car powered by sodium-ion batteries on public roads by mid-2026."
CATL is more credible than Donut, but both are making forward-looking statements.
CATL is "we're going to mass produce this specific well known technology" and while there's some question as to precise numbers for their implementation of it they aren't claiming anything surprising. A worst they're somewhat over optimistic and fail to be a commercial success. At best they're slightly under optimistic and are slightly more successful than anticipated. We can be confident they aren't flat out lying (though they may be exaggerating) because the claim is so mundane.
Donut is "we're going to produce a technology capable of achieving targets that haven't even been demonstrated in a (public) lab. We won't tell you what specific technology. We're going to put this miracle battery in motorcycles, because we can". At worst they're flat out lying to scam investors - but if they're not lying, even if they're over optimistic, they've made a significant advance in the state of the art that will eventually (once it's not just put in motorcycles) have widespread repercussions.