Comment by dzhiurgis
15 hours ago
> Lithium iron phosphate batteries are very practical
Unless you want to charge in negative temperatures
> However, this battery faces range limitations
Yes they are less dense but plentiful for typical passenger car (and not so much for full sized trucks or even "mid-sized" US SUVs).
> the issue of how to improve charging speed
I think CATL demonstrated 1MW charging on these already. Definitely shipping 500kW charging (tho best measure is still average km/hr).
> Solid-state batteries should be the next big thing
Sodium will (great cold weather performance and even better charge rates), but it's less (vol) dense and prices won't reach LFPs for another 10-15 years (unless you believe hype, not actual analysts).
> 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.
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>That's a hack, not a solution.
Why do you say that? It sounds like a simple solution to me.
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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.
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.
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.
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.
Those are quite niche environments. The success of LFP won't hinge on whether it works below -20C, obviously.
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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.
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.
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
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
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.
There are variants of the Model Y with LFP batteries.
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.
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.
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.
> 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.
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.
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.