I think CATL is promoting a hybrid pack of LFP and Sodium that would give you the cheapness and density of LFP, but with maybe 30% Sodium that you could use for a quick partial charge, and could also be used when the car is cold-soaked. Once you drive for a while, the whole pack gets warmed up and you can use the LFP.

Using lfp at low temp is not an issue. Charging is the problem.

> Charging is the problem.

Which also occurs while driving, whenever you're decelerating.

> Using lfp at low temp is not an issue

Bjorn managed to get couple cars in coldgate condition - so cold and such low SOC that it's just not enough power to heat up battery and now you going highway at 60 km/h. IDK, maybe just a software fix, maybe an edge case, but it can happen.

If it's suitable for sedans it's actually more suitable for SUVs. SUVs require less power per cubic feet of space. So there is more space available for them, even if they take more energy overall

There are variants of the Model Y with LFP batteries.

What? How does an SUV require less power per cf than a sedan? I would think that aero alone would always be worse for an SUV, making sedans more efficient.

I think he means less power per total overall volume of the vehicle. SUVs are certainly less efficient per mile, but their power requirements don't scale linearly with volume so you have a lot more "extra" room to place batteries, even if it is still entirely within the frame. So you can get away with less space efficient batteries.

Drag scales by frontal area (and the coefficient of drag tends to actually be lower on longer objects), so as long as the SUV is longer than a sedan, it'll tend to have less aerodynamic drag proportionally (rolling resistance scales with weight, though, so you still have to pay that cost).

An observation is the amount of power needed is proportional to some log of size and weight.

such strange unit of measurement. cubic feet of space. especially for civilian transport when most of the time no one uses that space. i mean most of the time its one person per car without any baggage. what's important is weight of the car. and i bet suv is heavier than sedans.

There are multiple variables, claiming weight is important is wrong.

Volume is important because the more volume the more space there is for batteries.

Aerodynamics is important because at common highway speeds this is the dominate energy cost. This is a factor that goes up by the square of speed, so at low speeds it doesn't matter but at high speeds it does.

Weight is least important because it has a linear change and is a small factor in efficiency.

There are real safety concerns with SUVs, but their larger size means there is more space for batteries and so they can overall go farther then a Sedan in normal driving despite the other costs.

I've tried to express SUV's as in American SUVs - full sized 7 seat monstrosity. Most EV SUVs right now are crossovers, i.e. Model Y. Cybertruck is closest approximation and it uses nearly 2x more power than Model Y. Even with ~most advanced batteries people still think Cybertruck's range is way too little whereas I'm pretty certain majority of Model Y's sold are LFPs.

For me in Europe the Y is a huge monstrosity... I'd want something about 16 inches shorter to get to normal crossover size.

> Unless you want to charge in negative temperatures

LFP charging in cold has pretty much been solved by adding a heater to battery pack.

> (Sodium-ion) prices won't reach LFPs for another 10-15 years (unless you believe hype, not actual analysts).

Given CATL is scaling sodium-ion production to to GWh scale next year, it sounds like they are betting for a much shorter timeframe.

> LFP charging in cold has pretty much been solved by adding a heater to battery pack.

That's a hack, not a solution.

> Given CATL is scaling sodium-ion production to to GWh scale next year, it sounds like they are betting for a much shorter timeframe.

Wanna bet? LFP is ~1,000 GWh scale right now. GWh scale is 0.1%.

I pulled into a Supercharger with my LFP-battery EV last winter. The temperature outside was -15C and I had not set the navigator so there was no pre-warming activated.

By the time I had finished my coffe, SoC had gone from 30-ish to 90-ish percent.

LFP tech anno 2023 is perfectly good enough for road tripping in large cars in severe winter conditions. For almost everyone.

So your battery was preheated. I once did the same with approx 0C battery temperature and whole ordeal took at least 2x longer. Yes there was farmers market in front of charge station so I had a good time with kiddo. That’s not the point.

Let’s not pretend better batteries shouldn’t exist.

Or just press the button to manually preheat the battery?

Heat pump barely works below -30C

Which doesn’t matter if your about to charge either way and just want to optimize time spent?

This can’t be more than single digit days per year? This is the case where people in for example Sweden have 230V engine block and passenger compartment heaters for their car.

It’s like the definition of an edge case.

I’ve often wondered:

It’s -30C and the heat pump doesn’t really work. Is there any advantage to heating the cold side with, say, a resistive heater?

Conservation of energy says no, but what if it’s also being heated by waste heat from charging the batteries?

(Maybe the answer is “if that’s the case, you are actively cooling the batteries with the heat pump!”, but I’d like to think someone more clever than me could make the scheme work.)

> It’s like the definition of an edge case.

Now imagine there's battery technology that solves that + removes equipment required for battery preheat...

Quoting Bender from Futurama: "Great is OK, but amazing would be great."

I'm not against further progress, I'm just stating that using current gen LFP in cold climate for large cars driving long distances is not a problem. It is more than fine. At least Tesla's implementation of LFP, I can't speak to any others on the market.

>That's a hack, not a solution.

Why do you say that? It sounds like a simple solution to me.

It takes hours to heat a cold large pack til it's warm enough to charge. That's a drawback.

All the EV owners in Scandinavia don’t have practical problems charging in winter at will.

Also Scandinavia is not that cold. Their winters are quite warm, actually.

Old article at this point, but it's trivial to prove false - https://insideevs.com/news/550021/cold-lfp-battery-tesla-mod...

Leave your car with 5% SOC overnight and then try to find energy in morning to preheat battery. People have painted into corner themselves before. It’s perfectly adequate for my very mild climate and even then I get limited regen about 6 morning months per year.

This is the EV equivalent of riding your old motorcycle with the reserve valve open the entire time.

You are driving a giant killing machine around... it isn't too much to ask that you have some foresight to avoid the situation you describe.

Yet life happens and weather isn’t always exactly predictable. Why you against better batteries?

I'm not against better batteries. I'm against people who choose to operate with such a small safety factor for something as serious as operating a giant rolling 2 ton piece of metal and volatile chemistry. Just like I'm against people who don't know how to change a tire or properly drive with etiquette on the interstate; If you can't do it, you kind of deserve some teasing.

In my friend group, if you run out of gas you get made fun of. You forget to flip your kill switch and can't crank your motorcycle, we all laugh and call you a dipshit.

Getting stranded isn't always harmless, and proper adults don't get stranded. Proper adults manage their vehicle safely. That's my point. Yes, exceptions are allowed, but we need to make sure everyone knows they are exceptions. Don't leave 5% on your battery when in the freezing seasons, it's improper.

> I'm against people who don't know how to change a tire

TBH that's majority of people. And it's a good thing since tyres got so good.

I get it tho. It's obvious. But it's better when things work better.

It's not obvious because you're still making the excuses for baby-adults. No one is saying battery tech should stop being developed, nor should pain points be unaddressed.

Because it doesn’t solve the problem, it merely works around it. Solving the problem would mean coming up with a battery chemistry that doesn’t suffer in the cold. Instead the answer is “just don’t have it get cold”.

It’s not to say a hack/workaround isn’t useful, and I would say that it’s perfectly acceptable to simply use a battery heater in the winter. But calling it “solved” confuses solutions and workarounds, and that’s an intellectually dishonest thing to do.

From the perspective of the user, battery being cold does not matter. How it does not matter i dont care about, for user it is solved.

Now, we can go into the weeds as to what constitutes solved and we might agree or disagree.

Isn't starting a fire under your engine to get it to start a hack too? I mean they could add a heater to the engine. Wait.

After market electric engine heaters and remote starters are typical for ICE vehicles in cold climates (e.g. Alaska). Not sure why you consider this to be a hack for EVs if its builtin to the battery pack design.

Does the heater handle real winters, like they have in Alaska, Mongolia, and parts of Russia north of it? Or just European and American "winters" where -20°C is considered hardcore? Gasoline powered engines handle this well, and you can warm them up with a gasoline torch if they stay outside for too long and refuse to start. The cold does not destroy them.

> Does the heater handle real winters, like they have in Alaska, Mongolia, and parts of Russia north of it? Or just European and American "winters" where -20°C is considered hardcore?

It handles "real winters" [1] where large portions of the human population live. [2][3][4]

[1] https://en.wikipedia.org/wiki/No_true_Scotsman

[2] https://www.bbc.co.uk/staticarchive/e4ff248622e19fa303d72e25...

[3] https://engaging-data.com/population-latitude-longitude/

[4] https://luminocity3d.org/WorldPopDen/

I don't see why a built-in heater is worse than aiming a torch at a car to get it to start. Seems like a major oversight for gasoline cars.

Also, a tiny fraction of the population will ever need to start their cars in Alaska, Mongolia, and Northern Russia. The small city worth of people living in these insane environments can stick to their wood-fueled diesel cars while the rest of the world just uses normal vehicles.

Those are quite niche environments. The success of LFP won't hinge on whether it works below -20C, obviously.

Most of the US Midwest sees -20 C for at least a brief period each winter. Having reduced functionality at those temps would be pretty inconvenient for the many car dependent people that live in the region.

Inconvenient for those people. About 8 billion other people don’t live in that type of weather.

They also mostly can't afford $25,000 cars.

About half of the world is within 3,300 km of a village in Burma, close to the Chinese border and not too far from Laos and Thailand.

China and India both have EVs much cheaper than we get in the EU. Like, "<€10k new" cheap.

What I do wonder about is how much of Africa can get EVs; I've only been once, to Nairobi over a decade ago, so take it with a pinch of anecdote-flavoured salt when I say that what I saw there was a lot of 20-30 year old vehicles.

Most of the people that can afford $25k cars do not live in places that go below -20C.

-20C is feasible. Charging will take a bit longer because the heater will need to work a bit longer, but as long as the batteries can reach about freezing temperature, you're good.

Charging being a couple minutes slower a few weeks a year is a minor convenience. If you have a house with a garage, like many people in the US Midwest, I doubt it even poses a problem even on the worst days. It's more in the winter-long -35C areas that (purpose-built) combustion engines have obvious benefits.

Cold climates suffer more from cold batteries having reduced range, but with modern battery ranges the problem isn't even that extreme anymore.

It entirely depends on the original range of the car.

Realistically you are looking at trimming 20->30% of the range. If you drive 20 miles a day but have a total range of 200 miles, then it's really not inconvenient. It only becomes inconvenient if you need to travel long distances.

Most of the Midwest also has snow and cannot farm the land for 7 months. What are you actually talking about here? That they cannot adapt or that they will refuse to work?

You can discharge the battery to power the heaters, at significant cost in energy. The temperature becomes a serious problem when charging (will physically destroy the battery through dentrite formation!), and under very high power draws (battery can’t keep up chemically).

It can be solved, but at a cost, and makes the tech much more dangerous - you could end up in a situation where you freeze to death somewhere more easily in the climates it is a problem.

It’s similar reasons why diesel isn’t a great idea in Alaska and the like too, and people tend towards gasoline even in situations where it is more costly and less efficient (like industrial trucks). It can be mitigated with chemical additives (‘heat’), tank and block heaters, etc. but has similar risks.

Alaska, Mongolia and Russia are extreme edge cases that I don’t believe hold much weight in an argument. It’s like those arguments where folks try to attack solar or wind, “solar won’t work on northern Alaskan winter”. Ok great that’s such a small slice of the population that it’s ok.

Are you a car ad where you're selling the most extreme off-road experience for the person who just wants to go to the grocery store?

Come on man. If you're in an extreme environment, get the tool appropriate for that environment. People in mountain environments tend to have 4WD or AWD cars because it's appropriate. Doesn't mean a non-AWD car is useless.

If you live in the extreme 5%, get something that works there. If you're in the rest of the 95%, other solutions work fine.

So largest battery manufacturer should drop their project, because “come on man”?

Negative temperatures or low temperatures are everywhere. Sodium will displace LFP pretty much everywhere (20 yrs), not just in extreme cold. I get slight coldgating 6months a year in warmest parts of New Zealand. It’s not even a minor issue, but if manufacturers can remove complexity - they will.

> Unless you want to charge in negative temperatures

Doesn’t the thermal management system of the battery packs handle this?

Yes, the largest issue is that they heating isn't enabled unless it's charging or 'knows' it will be soon.

Ps: the heating is increasingly heat pump based instead of resistive.

It does, but it costs is complex, requires power and time.

It's noticeable even in climates like NZ.

There are coldgating stories about LFP. Some even reduce output and very low SOC and temperature, so you drive 60km/h in highway.

Sodium is vastly superior here and CATL is not going to be giving it away for free.

I think it is fairly likely that sodium catches LFP in the ~5 year timeframe since sodium has a lot more promise for grid scale storage since it has no expensive materials.

When are the aluminum batteries coming?

It still does have expensive materials (cheaper form of graphite), but a little bit less of it, namely lithium and there's something else I can't remember.

The small handful of sodium batteries that are currently available retail all seem to have rather bad roundtrip efficiency compared to LFP and voltage drop starting at a high state of charge.

Also LFP prices dropped enough that shipping cost from China became a significant part of the price. This will be even more of a factor should the less energy dense sodium batteries ever reach the promised $30/kWh.

One thing I hadn't groked about Sodium Ion was the enormous Voltage range leads to a bit of an issue when it comes to current. You have a 4x voltage from top to bottom of the battery and this also means your current is 4x as well for the same power output. This becomes a bit of an issue and it is part of the efficiency equation, not just externally to the battery where wires have to be much larger than LFP or LI but internally due to internal resistance.

Ehhh not really a problem unless you idolize 12/48 V style systems that aren't adequate for these modern chemistries (i.e., non-lead-acid based) that scale down effectively to single digit amp hours per cell. You can keep the current around a comfortable 20A at any pack size, just by increasing the voltage. Say 5Ah cells. At 1.5kV (the highest easily practical with mainstream transistors and sticking to the "simple" circuit designs), that's 7.5kWh per such battery string.

That's a small home solar setup's entire battery.

Sodium gravimetric density is same. Volumetric is worse. Shipping containers generally cost by volume, but given how dense batteries are I suspect this won't matter.

I'd agree if you could stick them in the containers discharged, but you can't. This means that even safer chemistry like sodium battery is still hazardous cargo.

> Unless you want to charge in negative temperatures

I do all of my charging way above 0K. :-P

The issue I’ve heard with sodium-ion is that the voltage curves make the power electronics much more expensive for a given efficiency/power level.

[https://www.eevblog.com/forum/projects/sodium-ion-battery-ev...]

Lithium’s curve is nearly flat, which allows for a pretty easy consistent power production (albeit nearly impossible to tell state of charge!) since you only need to target a pretty narrow voltage band.

Overall, that means sodium-ion has to be even cheaper to be competitive, and it makes even less sense in areas where power density matters like electric cars, as you’ll end up with far less power and/or needing much heavier motors and more expensive electronics to compensate when on the lower end of charge.

I don’t want to think of what it would cost to do a 100kw buck-boost power supply that can handle +- 25% (or more!) voltage differences. In reality, I don’t think anyone would try.

I am not sure honestly about the negative temperature. Sure it can be a problem in extreme colds but most of the world does not live in those climates.

All modern EVs have tight thermal control of their battery packs to optimize lifespan and charging. They need to be cooled in the summer and heated in the winter.