alt Hacker NewsRetaining 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.
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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.
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...
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.
Why would that be a game changer? Genuinely curious.
Chemistry-wise it checks out, it was long touted advantage of sodium, just that they probably ignored rest of the problems in winter
>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
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