[Flavius]

Retaining 90% range at -40°C sounds like a game changer, almost too good to be true. I'm definitely going to need to see some third-party real-world range tests to validate those claims before getting too excited.

[teraflop]

Note that this article's summary has a significant error compared to the original press release[1]. The article says "90% range", whereas the press release says "90% capacity retention".

This is a big difference because there are all kinds of other factors besides energy capacity that can affect the efficiency of the whole system, and therefore affect range.

Most notably, air is about 28% denser at -40°C than at 25°C, so drag is about 28% higher. So you would expect roughly 28% less range at high speeds even if the battery has no capacity loss whatsoever.

As someone else mentioned, climate control also consumes a lot more power when it has to maintain a larger temperature difference between inside and outside.

[1]: https://www.catl.com/en/news/6720.html

[gucci-on-fleek]

> Most notably, air is about 28% denser at -40°C than at 25°C, so drag is about 28% higher. So you would expect roughly 28% less range at high speeds even if the battery has no capacity loss whatsoever.

With my gas car, I haven't noticed 30% worse fuel consumption at –30°C compared to +30°C [0]. To be fair, I haven't closely measured the fuel consumption at different temperatures, but I probably would have noticed such a big difference. This is just anecdotal of course, so your values may actually be correct.

[0]: It does occasionally get down to –40°C here, but my car won't usually start then, so I've slightly shifted your temperature range to the values where I've driven most.

[PunchyHamster]

I'd imagine also less rolling resistance from both rubber hardening and just roads being more slippery

But TBF same factors affect ICE cars

[jfengel]

That implies that air resistance is the overwhelming contributor at high speeds. Is that the case?

[bryanlarsen]

I don't imagine the difference is very significant on long drives. If the car is cold soaked at -30, it uses about 10kW for the first 3km. Then everything is warmed up, and the ~25% difference is increased consumption, not decreased battery capacity.

As long as you have a heat pump harvesting the waste heat to keep the battery up to temp.

But might be significant on short drives, 10kW for the first 3 km is massive.

[rayiner]

Yeah, this heat up effect is massive for around-town use. We have had below freezing weather for two weeks, which is very unusual here in Annapolis. That’s had a huge impact on my wife’s use case, which involves a bunch of 5-10 mile trips to drop the kids off at school, go on a grocery run, pick the kids up, take the kids to math tutoring, etc. She ran out of charge the other day during drop-off b/c the “37 miles left” we had the night before was actually a lot less than that accounting for warming the battery up the next day.

[tedd4u]

And human occupants will still run the heater more in winter. But it sounds like there could be a future where makers offer a sodium battery and heat pump version of their cars for sale in colder climates.

[metalman]

Running a preheater loop for the heat pump from the systems than need to be cooled, inverter and motor that run better cold,and other optimisations could likely supply cabin heat with very little battery draw, solar pv blended into the exterior could zero that out on an average basis,but 40 below is nothing to play with unless you know exactly what you are doing, even if they say it will still work.

https://electrek.co/2026/02/05/first-sodium-ion-battery-ev-d...

[rootusrootus]

> future where makers offer a sodium battery and heat pump version

AFAIK most EVs already use heat pumps today, so the future happens whenever sodium batteries become mainstream.

[jopsen]

I think our id.4 2023 model already has that. It has crappy software too. Great car, drives fantastically, but horrific software!

But if they add buttons back as planned, I might be willing to try a new id.4 in 5-10 years.

[epistasis]

Gasoline engines are already 15% less efficient at 20F.

https://www.energy.gov/energysaver/fuel-economy-cold-weather

At -40F (-40C), it's generally good practice to just stay inside and not drive at all...

[superjan]

That 15% loss reduces your range from 1000km to 850km? That hardly affects how useful the vehicle is. For EV that’s different story.

[seiferteric]

> Gasoline engines are already 15% less efficient at 20F.

Is that actually true once the engine has reached operating temperature?

[Joel_Mckay]

>almost too good to be true

Since the Lithium battery prices dropped, there are many Sodium battery companies simply abandoning the research or shuttering. Not a good sign when smart people jump ship.

The Na cells also have lower energy-density, and currently fewer viable charge cycles. One can still buy evaluation samples, but it takes time to figure out if the technology will make economic sense.

Best regards =3

[rootusrootus]

> many Sodium battery companies simply abandoning the research or shuttering

There could be other reasons. Maybe they just cannot compete with CATL.

[PunchyHamster]

Chemistry-wise it checks out, it was long touted advantage of sodium, just that they probably ignored rest of the problems in winter

[maayank]

Why would that be a game changer? Genuinely curious.

[minneapoliced]

With high-density energy carbohydrogens, you retain 100%.

[wpm]

And get 100% of the conflict and air pollution