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Question: if a LiIon battery can't deliver as much energy when cold, where does the lost energy go? Is it just unavailable, and becomes available again when warmed up? Is discharge less efficient, so the energy is wasted? Or does charging stop early when cold, so there's less to be discharged in the first place?

This is an educated guess, but I think it becomes less efficient, so it heats up, and then performs better as it heats. I assume this to be the case because I charge my RC plane LiPos the same way every time, and they take the same amount of energy, but flying in the winter gives much shorter flight times. Since the battery is warm after a flight, even in the cold, I don't think the energy is still there the battery is still discharged when I take it home), so it must just be much less efficient and wasting a lot of energy as heat.

I assume it's just that its internal resistance rises when it's cold, but I might be wrong.

> Is discharge less efficient, so the energy is wasted?

Yes. It's mostly wasted as heat inside the battery. I think there's also a temperature relationship to open-circuit voltage? But the predominate effect is from elevated internal resistance.

I believe you are correct. Temp causes the voltage to drop faster. It does raise as the battery heats up.

Batteries can freeze solid. It takes energy to keep them warm with an heater. Then there’s cabin heating which is usually warmed by heat from combustion in a gas engine.

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.

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.

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

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

But TBF same factors affect ICE cars

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

It's the majority, but overwhelming or not surprisingly appears to depend on car model, at least per some calculations someone on reddit ran [1].

I'd add though that rolling resistance tends to be higher, on average, in winter too. When there's often a bit of snow on the roads... Less so on high speed highways admittedly.

[1] https://www.reddit.com/r/askscience/comments/l2cq6b/comment/...

Considering air resistance is proportional to the cube of the speed, it would be highly surprising to not be the case.

It goes with the cube in terms of power, but with the square in terms of energy/distance, which is usually what you'd care about.

Define ‘high speeds’. There’s a reason race cars look like they do, to the point of having serious problems driving at speeds just a bit below highway speed limit.

Yes it is.

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.

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.

> 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.

IIRC there are some surprising holdouts, at least in the NA market. For example as far as I'm aware the Mustang Mach-E still ships with a resistive heater.

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...

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...

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

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

The temperature difference should in principle increase thermodynamic efficiency. You get loss of MPG from other factors though mentioned in the link, like increased friction of moving parts, idling to warm up (0MPG), defrosters/seat heaters, lower tire pressure, denser air to drive through, winter fuel mixes which may not have as much energy, etc.

Short trips are worse:

> Fuel economy tests show that, in city driving, a conventional gasoline car's gas mileage is roughly 15% lower at 20°F than it would be at 77°F. It can drop as much as 24% for short (3- to 4-mile) trips.

Once had a Porsche 914. Air cooled engine. Drove it across Montana and the Dakotas one winter. One very cold winter.

Not sure the engine ever reached "operating temperature" on that drive.

Assuming you can get the car to start (mine needs an engine warmer at that temperature), it takes at least 15 minutes of driving to reach that temperature. Unless you’re going on a longer trip the engine most likely wont be warm by the time you reach your destination.

I had to drive in -30C once, the engine could not get up to final temperature after 2 hours of highway driving because I had to run cabin heater at full blast on windshield and side windows so they didn't cover with fog inside. But that was in very old low power car.

Garages exist though.

Schrodingers garage. Ceases to exists when talking about EV charging but exists when ICE vehicles need cold starts.

Heated ones are rarer.

Well you have to keep it at operating temperature

There are a bunch of things going on, and some people's measure of efficiency needs work.

1) winter blend fuels have less energy per volume, that doesn't make your engine any less efficient by energy but it does by volume of gas

2) lots of temporary cold effects: fuel vaporization, thick lubricants, etc. these things become less of a problem as the engine warms up but some energy is still lost on long drives

3) air resistance: all aerodynamic forces are linearly proportional with air density. At a constant pressure there's about a 15% difference in air density between the hottest and coldest places you can drive (and thus 15% less drag on a hot summer day than a cold winter day). aerodynamic forces are proportional to the square of your velocity and they become the largest resistive force around 50mph -- so at highway speeds you're losing efficiency because you have to push more air out of the way

4) energy used to maintain temperature: this is hard to calculate but some engine power is lost because the energy is used heating up the engine block and lost to the environment

5) the Thermodynamics 101 engine efficiency goes UP with increased temperature, but it's got a lot of real world effects to compete with, no spherical cows and all

Partial pressure variant fx on combustion outputs

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

How many vehicles have a 650 mile range? Almost none. Plus you can't fill up at home with gasoline, like you can with an EV.

you can have drum of fuel enough for entire winter in your garage, the fuck you mean by "can't fill up at home"?

They mean that rounded to the nearest percent, 0% of people will be filling up their car at home from a drum.

Every modern passenger car will show you 650 miles when driving at ~60mph. In the EU, anyway, and with a diesel engine.

> How many vehicles have a 650 mile range? Almost none.

'22 Ford Escape hybrid

The remaining miles thing shows less than that on a full tank, but I've been pretty consistently getting upper-600s between fill-ups.

I suppose it would probably be less if I went on the interstate more.

There's one. Go to a Car and Driver article about cars with extreme ranges, namely those over 650 miles, and they will start listing out particular years' models over a 10 year period in order to get to even ~10 models, and most of them are EcoBoost or variants or poor selling hybrid versions of other cars.

Assuming a 1000km range is a very strange thing to do, as it's a fringe feature that almost no one needs or wants! Recall that "almost no one" means that there's still some, an existence of a handful of people on HN is quite consistent with "almost none."

Comparing range of gasoline cars is idiotic. There are plenty of cars with long range (1000km), and they all have 60L+ fuel tanks and most run on diesel (which gives you ~15% more range per liter). It'd even argue the same for BEVs. More battery is more range.

You mean EVs? Yeah, none that I'm aware of. But petrol/diesel cars? Loads of them. Even my 400bhp Volvo XC60 will easily do 650 miles on one tank of fuel. A diesel one will do 700-800. And a diesel Passat will go over 1000 miles on a tank without trying. Hell, even my basic 1.6dCI Qashqai could do 700 miles on its 55 litre tank

Volvo xc60 has an estimated 25 mpg overall (https://www.volvocarsrichmond.com/volvo-xc60-mpg.htm)

It has an 18.8 gallon fuel capacity (https://www.volvocars.com/lb/support/car/xc60/article/dfc6f0...)

That’s a max range of 470 miles. You would need much greater fuel efficiency above 34 mpg to get to 650 miles on an 18.8 gallon tank.

Cool, I guess when I did 700 miles on a single tank of fuel driving Switzerland to Italy and then again driving Italy to Austria and then again Austria to Netherlands this summer I just imagined it. My total for the 3000 miles was 38mpg(imperial).

Also you are quoting a value for the B5, which is not what I have, mine is a T8(and before you ask - no, I didn't have any opportunity to charge it anywhere on the way).

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

What I wanted to know from the article:

  The CATL Naxtra sodium-ion battery will debut in the Changan Nevo A06 sedan, delivering an estimated range of around 400 kilometers (249 miles) on the China Light-Duty Test Cycle.

   It delivers 175 watt-hours per kilogram of energy density, which is lower than nickel-rich chemistries but roughly on par with LFP

Thanks, I wanted to know about price. Isn't that the main benefit of sodium-ion. On par energy density with LFP, but a lot cheaper.

*potentially a lot cheaper.

I've seen that repeated a lot but I still can't buy sodium batteries cheaper than lifepo...

Sodium batteries don't yet have the scale that lifepo4 batteries have. I'd expect we will see them get cheaper.

Dumb question but I’ve always wondered if we could make a giant “hand warmer” type chemistry around the battery and use that to get it going in cold environments.

One way I've seen of doing this is to include a PTC heater. It's a heating element that you feed DC. It has a positive coefficient of resistivity vs. temperature, so it'll asymptotically approach a temperature defined by the structure of the material. No PID controller required, it's just a sheet of material you include in the battery structure.

Granted, you have a minor bootstrapping issue wherein you need the battery to be warm before you use battery power, but at very low % of the battery's power capacity I suspect it's less of an issue.

Less bloated site:

https://carnewschina.com/2026/01/22/catl-unveils-worlds-firs...

Do any US automakers have anything in the pipes using Sodium-Ion batteries? A quick search turned up info on a plant mass producing the batteries in Holland, MI but no mention of when they would be available. As someone in the market for an EV within the next year or 2, and also currently enduring a month long stretch of temps in the single digits and below, cold weather performance has suddenly become a huge consideration.

Likely No. Undecided with Matt Ferrell recently did a video on how sodium ion batterys startup in the US (not necessarily for EVs, but other power applications) have had challenges largely due to the falling price of lithium making sodium batteries less competitive on price the past couple years: https://m.youtube.com/watch?v=nrTCgZmUFCY

OTOH, there are seemingly more lithium iron phosphate (LFP) battery ev options now - rivian now uses LFP, Ford mustang mach-e has had a LFP variant since fall 2023 (and should have other models using LFP in 2027), I think the 2026 chevy bolt uses LFP, etc.

LFP battery production in the US only recently reached larger scale; so I expect it will be a while before they get around to sodium ion. With all the tariffs, they'd have to license technology and build local factories to get started. That will probably be a few years at least. Or the tariffs might become more reasonable at some point and they could import battery cells a bit sooner than that. But probably not until the end of this decade.

Cold weather performance with heat pumps and lithium batteries is fine. Don't worry about it. I wouldn't try to hold my breath until a US automaker produces a sodium battery EV.

It’s only “fine” if you live in the southern US where freezing conditions are rare and/or never drive anywhere near your winter range and you have a garage charger or some other easy access to a charge station. Anything outside of those conditions and winter range issues are painful.

Yes, most people don’t drive 200 mi/day. It’s really ok.

And yet, some of the biggest proponents of EVs live in frigid areas of Canada and the US. As it turns out, range loss is not really a huge deal for a lot of people, but being able to get in your car and drive without worrying about whether it will start at all is nice. No plugging in a block heater, no worry about fuel gelling, no warm up time. And you can pre-condition the interior so it is warm when you get in. With a modern EV you could lose 50% range and still have plenty for your daily commute. Even a fairly long commute.

Norway regularly sees -30C in winter and EVs account for like 99% of sales there, it made the news that in January only 7 ICE cars were sold in the entire country.

It's also a different country with a different culture, etc. Norwegians drive roughly 50% less than people in the US. There's probably a bunch of contributing factors, but the point is that reduced range is less of a problem if you drive less.

I'll be the first to say we need less range anxiety, and Norway is awesome. But we need to be careful comparing the US to Norway here.

Nah dude, I live in Canada, we're having a record cold winter here, and it's really not bad. My car (Polestar 2) is one of the least efficient, has no heat pump in my year, and only has a ~225km effective range in winter (~300 in summer) but .. I have zero range anxiety, there's no pain, it's not annoying. The number of times one is driving that far in a single trip is miniscule, but there's DC fast chargers all along the highways that take the edge off, and there are cars with far larger range anyways.

Having a garage charger and never driving more than your winter range on any given day is a pretty common situation.

If you remove Tesla and Rivian from the equation, US automakers are actively curtailing EV production period.

The US administration has basically told them to do so.

So don't expect any innovation on this front from the middle of the North American continent. It's being actively sabotaged.

> The US administration has basically told them to do so.

Any US automaker relying on Trump staying in office is playing with fire. Yes, you may see reduced or zero press releases and budgets for EV research being "reallocated" on paper so the toddler in chief doesn't get a public tantrum - but assuming there will be free and fair elections this year, it is highly, highly likely that Congress will be solid blue and reinstate a lot of what Trump has cut down, only this time as an actual law that is far harder to cancel than executive orders.

And everyone not hedging for this possibility will wreck their company's future.

“As always, we’ll have to wait for independent testing for real-world results.”

interested in hot desert weather performance which often gets lost in the averages.

Generally just not an issue. The biggest problem with deserts is battery degradation and not so much range problems.

If this is “on par” with LFP energy density, I’m not sure there’s any need for LFP now. Sodium ion seems to thoroughly beat it in every other metric.

On par on a per kg basis, but is it on par on a volume basis? If it takes up more space, that might pose packaging challenges relative to LFP.

Sodium has greater density than lithium, while most other materials used in a battery have similar densities regardless if sodium or lithium is used, so if a Na-ion battery and a LFP battery have about the same mass and stored energy, it is likely that the sodium-ion battery has a smaller volume.

that doesn't check out, capacity depends on surface area, if the element that is on the surface is heavier then, all other things equal, the battery will be heavier for same kWh.

Sodium would need to be more efficient to be lighter, which it isn't

The maximum deliverable power depends on electrode area, through the maximum current density.

The capacity of storing energy does not depend at all on area, but only on the mass of sodium contained in the battery and on the efficiency of using it (i.e. between full discharge and full charge not 100% of the sodium or lithium is cycled between the 2 oxidation states, but a fraction, e.g. 90%).

Any battery has both an energy density and a power density, which are weakly correlated and the correlation may have opposite signs, i.e. for some batteries it may be possible to increase the power density if the energy density is lowered and vice-versa.

For a given stored energy in kWh, the required mass of sodium is several times greater than the corresponding mass of lithium, by a factor that is the product of the atomic mass ratio with the ratio between the battery voltages. The voltages are similar, with a slight advantage for sodium, so the required mass of sodium is about 3 times the corresponding mass of lithium.

If the complete batteries have about the same mass, that means that other components of the sodium-ion battery are smaller and/or lighter.

Energy density of Na cells is lower, but it is the viable charge cycle count that is the show stopper issue for most markets. =3

They are also safer.

Na will be big in grid storage, it's a perfect fit.

I have no idea about the characteristics of these new sodium-ion batteries, but there is a great likelihood that they auto-discharge much faster than LFP batteries.

This means that if you do not use the car for some time, you may need to recharge it before you can use it again. This may be a problem if the car is left far from a charger.

Otherwise I agree with what you said.

I haven’t seen any info on charging speed. Can you recharge these as quickly as LFP?

CATL's Naxtra cells apparently have a c rating of 5C. Which boils down to about 12 minutes for a full charge with the right charger. So, as fast or faster than LFP would be the answer here.

If they have a 5C rating from 0 to 100 that would be a real game changer. I look forward to the days we don't need caveats like "only up to 80%".

This is awesome and I'm really happy to see this progress. Landing a new chemistry in a production car THIS YEAR is some crazy velocity, especially compared to where other Na-Ion batteries are in the development cycle elsewhere. Is anyone else even close to having a car on the road with their cells?

The reason this is so exciting for me personally is for stationary energy. Because the raw materials are so abundant and have good cold weather performance, both grid and home level energy storage costs should come down significantly as this is commercialized further.

Out the gate, sodium ion advantages are so significant that unless there is some surprise show-stopper it will likely become the dominant energy storage medium.

Crustal abundance up to 1000x that of lithium - pretty much every nation has effectively unlimited supply, it's no longer a barrier or a geographically limited resource like lithium.

No significant damage going down to 0V, can even be stored at 0V - much safer than lithium which gets excitable once out of its prefered voltage range.

Cold weather performance down to -30C - northern latitude users don't have as much range anxiety in the winter.

Basically, the only problem I see is that companies that have made significant long-term investments in lithium could take a big hit. Countries that banked on their lithium reserves as a key future resource for will have to adjust their strategy.

Lithium batteries will likely still have a place in the high performance realm but but for the majority of run-of-the-mill applications - everything from customer electronics to EVs to offgrid storage - it's hard to see how sodium-ion wouldn't quickly replace it.

Energy density matters a lot for many applications, including customer electroncs and EVs. Sodium ion is at a fundamental disadvantage (sodium is heavier than lithium).

I don't doubt that sodium ion has a place... but whether it takes over as the dominant battery type for portable applications strikes me as very dependent on the future of lithium extraction. It seems like a place that has a lot of room to grow more efficient and thus more competitive on cost.

No mention of degradation as a result of recharge cycles. So many of my electronic devices have had to be disposed of because the battery would no longer hold a charge. This is also a big factor in EVs and their loss of value over time.

Can/will sodium ion go spicy pillow?

CATL claims 10,000 cycles for the Naxtra:

https://battery-news.de/en/2026/01/26/catl-presents-sodium-i...

It seems the remaining disadvantage is energy density. If they can figure that out, it should win?

It is impossible for sodium-ion batteries to reach the same energy density as the best lithium-ion batteries.

So lithium-ion batteries will never be replaced in smartphones or laptops by sodium-ion batteries.

But there are plenty of applications where the energy density of sodium-ion batteries is sufficient. Eventually sodium-ion batteries will be much cheaper and this is why they will replace lithium-ion batteries in all cheap cars and for most stationary energy storage (except when lower auto-discharge is desired).

Nothing in the article really substantiates the headline (currently "The First Sodium-Ion Battery EV IS a Winter Range Monster").

The EV described in the article has a standardized range of 250 miles. This isn't a range monster in any condition. There is some gesturing that Sodium batteries don't require as much active heating in cold conditions. But nothing is quantified.

As usual with sci-tech broadly and batteries specifically: it's exciting that sodium batteries are coming to market; we can be optimistic that maybe in the future they will provide lots of range, or be less expensive, or maybe less flammable than today's lithium batteries. But the marketing hype is running miles ahead of reality.

> less flammable than today's lithium batteries

If we put aside the politics, what are the actual statistics behind lithium battery fires today? And don't LFP's have negligible fire risk?

I feel like my gasser F250 had a higher risk of spontaneously combusting.

The problem isn't spontaneous combustion, it's having an accident where the battery is damaged, causing runaway combustion.

No one burned to death inside a Tesla while driving normally. It's always following a crash.

I'd imagine if tesla stared to burn they wouldn't "drive normally"...

Unlike in traditional vehicles, most EVs have such a robust firewall between the battery and the passenger compartments you literally have 1+ minute to get out, compared to often seconds in a traditional vehicle.

And I've been following Polish firefighters reports about EV fires and they are very interesting - basically saying that in all recent cases of EV fires they were contained so quickly even the interior was largely undamaged - something that practically never happens with regular cars. Some of these have been in underground garages too, with difficulty of access - but nowadays they just know how to approach an EV fire and containment isn't a problem.

> Unlike LFP or nickel-manganese-cobalt (NMC) packs, it reportedly avoids severe winter range loss, retaining more than 90% of its range at -40 degrees C (-40 degrees F). Power delivery is also said to remain stable at temperatures as low as -50 degrees C (-58 degrees F).

That is exactly the substance of the headline.

It makes this claim:

"The Long-Range Version sets a new record for light commercial vehicles with a single-pack capacity of 253 kWh, achieving a maximum range of 800km."

That would be some 720 km at -40 C if the numbers are correct. I'm not well versed in this area and not sure if these batteries are comparable to those in personal vehicles, but the ones I've heard owners talk about have a reach at about half that if it's cold at all.

Even 620 would be absolutely not an issue, this is the difference I get from my diesel car basically

> But the marketing hype is running miles ahead of reality.

The marketing hype is the true range monster

I don't understand what these headlines are really about, given that 75% of the range loss in my EV is from CABIN climate control.

That seems really out of proportion with the experience of others, you may want to get it checked out. Do you have an older model with resistive heat and no seat heaters?

My EV is absolutely terrible range wise at cold weather. It is EPA rated at 220miles of range. I only see that when the temperature is at or above 80F.

Most of the winter it tells me I can only do between 100 and 120 miles. It is definitely half the EPA range with climate controls disabled at 0F. (Ask me how I know).

I love driving it in the winter. I don't have a pressing need to go long distances, so that is not a current concern. Not having to stand outside in the bitter cold to fuel up in absolutely awesome.

There are EVs on the market that do much, much better than mine in cool weather and I now know what to look for.

To really penetrate the midwest it will take a car that can realistically do a road trip to Florida from say Duluth, MN or Michigan's UP in the winter.

Because not only do folks in the midwest drive long distances without a second thought, they sometimes do it in the cold of winter so they can get a break from the snow.

So yes still getting 90% of the range at -40C does sound attractive.

Does your vehicle have a heat pump?

This with 500-600 miles range means the end of ICE. 250 is still too little since that will realistically be closer to 150-160 if you’re consistently driving 74-80 mph.

Unfortunately sodium ion is less dense than lithium ion, so range is lower too.

Since it's also cheaper, it's likely that Na-ion will be adopted by cheaper city runabout type EVs, while premium long range EVs will continue using Li-ion.

I saw a CATL presentation where they were hyping a hybrid lithium-sodium pack. Their version of sodium ion could charge/discharge faster than LFP, and handle lower temperatures. The hybrid then gives you a nice combination of features. You get better density/range from LFP, but if you have to start in the cold, the sodium-ion can get you going, and then with active cooling you can heat the LFP using the waste heat from the sodium ion for the rest of the trip. Since the sodium ion charges faster, you can charge part of the overall pack really fast, so you can make a quick trip to the charger and add ~50%. If you live in a cold climate area it seems like a very good combination.

Incrementally better. But not a monster.

I suspect we will be finding this technology being used a fair bit in aerospace tech like satellites to compliment the onboard solar, given the low-temp operational capability.

Do satellite batteries run cold?

Given the difficulty of radiating heat away I would have expected the opposite.

Especially considering the incentive to send up as little battery as possible, and the very predictable day/night cycle leading to the ability to precisely predict how small a battery you can get away with...

Generally it's hard to control: it'll be hot sometimes and cold other times, so a wide operating time is useful.