I found the point about the safer qualities of LFP battery chemistry reducing the overhead in the battery pack construction and thus preserving range despite lower capacity very interesting.
Better range on a lower capacity means much better range per hour charging time.
That is not necessarily true, check out the max C rate in of LFP. Still, LFP is the way to go for sure; longer overall life is a clear net positive, lower degradation and secondary market uses once the véhicule is junk without expensive and heavy recycling. I bet the cyber and truck were waiting on these patents to lapse.
Completely agree. I had a thermodynamics teacher in college say “in the history of transportation we’ve never switched to something powered by lower energy density [than the previous mode of transportation]"
in other words “energy density wins the day".*
That was running through my head when I read they were switching to technology with lower energy density but, to your point and to the article's point, it’s really about systems level energy density and not cell level energy density.
* with Tesla we have now seen that there is another factor, convenience, that my professor did not account for. I own a Tesla and the primary selling point… OK it was acceleration… But the secondary selling point was never having to go to a gas station again when I am just barely going to make the meeting and forgot to fill my gas tank the night before.
Before we had good EVs (If I remember right electric vehicles at the time had something like 60 miles of range... I might be off, though. That was about 14 years ago)
Exactly how many data points did he have in this thesis? Running, horse, bike, car, train (coal, electric, diesel), plane? There's lots of places which have flip flopped, e.g. Italy going from train -> Alitalia -> high speed rail
Wouldn't it be more like running, horse, better horse because of improved diet, better horse because of improved medicine, bike, better bike because of gears, better bike because of better gears, car, better car because of better fuel, better car because of better fuel, better car because of better fuel, better car because of better fuel, better car because of better fuel, better car because of better fuel...
At some point economical aspects are also important. If fuel was available for gas engines but it was rare, it doesn't matter how energy-dense it is if it's expensive.
yep. The Soyuz was supposed to run on Syntin but then they reverted back because the added energy density and payload capacity (something like 30%) was not worth the manufacturing cost.
Energy density must be calculated from useful energy (work) after conversion loss. By that metric gas burned in an ICE is not much better than lithium batteries. The latter store less energy but it’s extraction is over 90% efficient.
Most of the energy you buy with a tank of gas goes to heat the air around and behind the car as you drive.
The weight of a full gas tank that can drive you 1000km is a lot less than the weight of batteries that can do the same. even if you include the ICE engine.
In other words: even when you take conversion into account, energy density (both by weight and volume) is better in gasoline than battery.
(I love BEV, and I see it will win over most of the market, but gas wins on energy density)
> But the secondary selling point was never having to go to a gas station again when I am just barely going to make the meeting and forgot to fill my gas tank the night before.
Curious example since that's one of the drawbacks of an EV. If you forgot to fill the gas tank and have to stop, you'll be 5 minutes late. But if you forgot to charge the EV, now you're looking at several hours late (or give up and call a cab).
So I have actually been in (close to) this situation.
i’ll address a couple of things though… First, since you plug-in every day at home it is very very rare for me to forget. Second, the total available range is still close to my old gas cars which means I need to have forgotten for many days in a row which in the last nine months has never happened.
BUT, I did say that I was low on energy on a day I needed to make a long drive…
Backstory was I was intentionally draining my battery over a period of about a week without charging (trying to recalibrate the gauges... very rare to do).
In the morning on a day I needed to make a three hour round-trip drive I realized I was at 20% power.
So I hightailed it to the nearest Tesla supercharger, plugged in, pulled out my laptop (I'm sitting on a giant battery... powering a MacBook is no issue) to get some work done, and 20 minutes later I was at 80% (enough for 200 miles - or my entire round trip).
So the power issue was caused semi-intentionally and entirely my fault but also it took very little time to solve it. It would be a bigger issue for somebody who isn’t near a supercharger (and no 220 line at home as they'll go 0->full overnight) but again it is very very easy to remember to plug-in at night and many/most people would generally need to forget to charge for at least three or four days before it becomes an issue.
> Second, the total available range is still close to my old gas cars
If the range is so huge, I see it might not be an issue.
We have a Fiat 500e, so forgetting to charge overnight (or if the timer didn't go on as intended for whatever reason) means a guaranteed crisis in the morning as there's no way to get to work.
> Better range on a lower capacity means much better range per hour charging time.
It doesn't work like that unfortunately. Unless you're using a low power charger charging time is limited by the C rating of the battery and that is independent of how big your battery is.
> Better range on a lower capacity means much better range per hour charging time.
That's not what they're saying, this is about space required to get the same capacity.
The relevant quote is "meaning that energy density at the pack level should compensate". What's going on is that the chemistry energy density is lower, so you need bigger batteries to get the same capacity (i.e. range). Normally this means you would need more space in your vehicle to get the same range, however you need less cooling so you save some space there so the overall space usage of the battery system ends up about the same.
Presumably building NCA batteries for the Model S and long-range versions of the other models.
Possibly building LFP batteries as well now that the patents have expired. The reason CATL has such a lead on LFP manufacturing is that they had a free license for using LFP patents for domestic consumption in China.
There is still no Tesla Semi after 4 years, so maybe the factory could be devoted to that, but even the gigafactory's battery cells don't make sense for a long range semi as originally shown. Bill Gates was right about the physics of it not making sense with those cells (too heavy for bridges with any decent payload), and they will need to turn it instead into a low range around-town Pepsi delivery tuck, as already announced.
Even though I own a Tesla and love it I can’t see a fully electric, long-haul semi making sense for quite some time.
For consumers (at least in my own experience) there is a range threshold that, once surpassed, means I almost never have to worry about fill ups again. So the Every day convenience outweighs the once or twice a year inconvenience of longer “fill ups“ vs gas for extended drives.
I bought mine because I hate little annoyances like having to remember/go to the gas station and fill up periodically.
For long-haul trucking though Tesla's benefits would be in automation/assisted driving, not in electrification. Short of some sort of carbon credits/regulations it’s difficult to imagine widespread adoption of a technology that has more downtime and higher initial costs than a previous technology.
The stop/start of small truck deliveries (and subsequent energy recapture) makes sense but for long-haul I can’t see it feasible until the battery energy densities jump by a sizable margin without a corresponding increase in price.
And at that point there's still few financial advantages of electrification I can think of... what am I missing there?
Delivery or recycling/garbage makes sense first, due to stop and go regen. Long range never made sense as a first step but the FSD replacing truckers and truck-train angle was used to lure in investors, even though it has no relevance to diesel vs. electric (or even better fit for diesel to power the compute without impacting range, remember we're talking 2017/2018 compute for when it was announced).
They say in the title "All Standard Range Teslas", but only the Model 3 has a standard range version and they're still like 2-3 years away from their compact/25K car.
The linked article's title is "Tesla made $1.6 billion in Q3, is switching to LFP batteries globally" and it's a little more appropriate as it split about 50-50 between discussing earnings and discussing battery technology.
I say this because there’s another article from the New York Times about Tesla‘s earnings on HN's front page and this one from Ars is more technical, more straightforwardly written, and much less hyperbolic than the NYT version. (This one focuses on earnings and potential major changes that could impact the bottom line versus New York Times spends 50% of their article discussing government inquiries into autopilot.)
I can't update the title but would recommend this article over the New York Times one.
when I read the article this was what stood out to me, as well. Last winter it got _really_ cold where I live. Does that mean that if I got a Tesla with an LFP battery it would be drastically less useful in the winter? Seems problematic.
The battery can be heated, so you can reduce the cold weather range problems by preconditioning the battery before a drive. Naturally this uses some power, so Tesla recommends keeping the car plugged in when it's cold so it can keep everything nice and warm.
No different than using a block heater or diesel coolant heater then. ICE vehicles use a lot more fuel in winter too, and take a long time to get up to temperature.
Indeed. Telsa's will keep batteries at reasonable temperatures when plugged in, but not optimal. There is a departure setting available so you can make sure your battery is full and at the ideal temperature for any scheduled departures.
Would be interesting to know whats going on in the industry with LFP. Pre-built lead acid replacement LFP battery prices have been dropping almost daily and are down to high end AGM prices [1] and quality has been going up [2], these batteries were twice the price a year ago.
Will be replacing the lead acid in my RV soon with LFP's, it really a no brainer.
Can you help me understand why you wouldn't just stay with the old Lead-Acid batteries? You can get a 150Ah for $110, for example, whereas this 100Ah you linked to is $376.
I'm sure there are benefits, but I don't know much about batteries to understand why you'd make that tradeoff.
You can't discharge lead-acid as deeply as LFP without destroying longevity. So that 150Ah, probably only has 75Ah of useable capacity.
The LFP battery will also last for ~5000 cycles, after which it'll still have ~80% capacity, and thus is still valuable. Lead acid only has a life of 500~1200 cycles. In other words: you'll have replaced the lead acid battery 4~10 times before you need to replace the LFP.
IIRC, lead acid has a higher voltage drop when drawing a lot of current. Meaning that with LFP you can power larger loads.
Taken together, for most use-cases, the lifetime TCO of LFP is better than lead acid.
> The LFP battery will also last for ~5000 cycles, after which it'll still have ~80% capacity, and thus is still valuable. Lead acid only has a life of 500~1200 cycles. In other words: you'll have replaced the lead acid battery 4~10 times before you need to replace the LFP.
What happens if you keep using the LFP battery after that? Does the capacity continue to fall to zero, or is there some point it levels off and you can use it indefinitely after that if you don't mind the reduced capacity?
The curve seems to be pretty lineair. So I think you can do another 5k cycles and have 60% left, once more for 40% etc. A quick search didn’t reveal a full curve chart to zero though. I know that a lot of cheaper LFP cells on aliexpress are used “grade B” cells, eg cells that had an original capacity of 120Ah that are resold as 90Ah cells after their first 5k cycles.
Peukerts law does not really apply to lithiums [1] so with lead acid your capacity is greatly reduced if you do high amp draws.
You can really only use 50% of lead acid capacity without significantly effecting their lifetime, so most people cut the capacity in half when discussing, lithium can be run to 80% without issue and really even 100% with minimal loss and LFP's have much greater cycle than lead anyway so you probably pay less in the long run with a LFP than buying multiple lead.
LFP hold their voltage pretty consistently right up to the end of the discharge cycle while lead acid will drop significantly, this increases amp draw and has other negative effects (dimming light etc). The low internal resistance makes them pretty stiff voltage sources.
LFP accept bulk charge much longer before hitting absorb than lead so they can be charged much faster, this helps when charging from a generator as you don't have to run it as long to get full charge. Also you don't really have to worry about partial charging, where as with lead you want to do a full absorb regularly to keep their capacity up.
At least half the wieght.
Top tier lead AGM like Lifelines are basically the same price, I have these in my RV now and are a out 7 years old and now need to be replaced due to not holding a charge. Lifelines are considered gold standard and have high charge and discharge capability for lead acid, but LFP still blow them away, so no reason to go that route again.
Those cheap lead acids are not going to be decent deep cycle and will be wet cells, so will have off gassing and cause corrosion. AGM solve that and good deep cycle AGM's are not cheap, see Lifeline, Trojan etc. You can get relatively cheep "golf cart" batteries but again wet cells that need water checked and have to vented properly.
There are downsides to LFP:
More complicated, they need a BMS to protect from over and under charge, the BMS has current limits due to using FETs to switch on/off, so most of the drop in replacements can only do 100 amp continuous with short burst of say 300 amps. So they are not great engine starting batteries. You can run in parallel to get more current capacity obviously. BMS is a full microcontroller with high current disconnect so much more to go wrong, although some have bluetooth with an app to monitor individual cells etc.
They can't be charged below freezing without damage, so most BMS have low temp disconnect to protect against that. Also there overall temp range is narrower than good lead acid, my lifeline are rated -40f to 160f I believe. Lead acid are simple tough and reliable.
Last I heard, LFP had some significant temperature restrictions compared to lead acid, making them unsuitable for use in cold temperatures. Has that changed?
What is the situation these days with infringement of major IP by Chinese companies? If they've had a battery chemistry to themselves for a while it sounds like they're having their cake and eating.
I have first hand knowledge where at the small and medium scale, Chinese manufacturers will happily knock off major brands and steal technology to make products, and as a non-Chinese IP owner you have very little recourse. Is this situation still how it works for key IP from major companies or if you're (e.g.) Tesla and you had a patent on battery technology, could you realistically enforce it in China?
Does anyone know if 20 years from now these batteries start to burn down homes will Tesla be required to fix the problem similar to how traditional auto companies fix bad air bags or whatever issue that could kill people even decades later?
It's a legal and therefore a cost driven move - - less lawsuits from batteries catching on fire - - less performance from the iron phosphate version too, less range, cobalt in pyro lithium batteries is expensive . . .
Most of cell energy density comparison don't remove cell casings mass from comparison.
This way pouch cells outperform hard cased ones so much on capacity, but in reality it's a big delusion as you still have to put structure to hold cells in place — and you can't do it with flimsy, paper thin casings.
The potential for a massive jump in battery chemistry is why I personally have not purchased a BEV yet. I'm leasing a LEAF, which has been great overall, but I'm not going to buy until the battery chemistry is settled here in a few years. There's a high probability that every BEV on the road today will be considered antiquated (and potentially unsafe) in 5 years.
Yep. I feel like buying an EV now is like buying a $50,000 PC that will be obsolete the minute I take it home.
EVs are insanely awesome though. I'm leasing a 2019 Bolt and after a month or so it's the best car I've ever driven. EV torque is a blast. With the type of driving I do I'm able to get by on a Type I charger at my apartment and a rare visit to a public charging station. I think one-pedal mode helps because I'm barely ever using the brakes.
Yes, if you can wait it's probably best to do so. But if you can't wait I imagine an EV bought today will hold its value a lot better than an ICE vehicle.
Not clear that’s the case. BEV will become more common as production ramps up. Unit costs will come down. No way BEV are the dominant form of transportation at a sales price >$40k.
63 comments
[ 2.9 ms ] story [ 112 ms ] threadBetter range on a lower capacity means much better range per hour charging time.
in other words “energy density wins the day".*
That was running through my head when I read they were switching to technology with lower energy density but, to your point and to the article's point, it’s really about systems level energy density and not cell level energy density.
* with Tesla we have now seen that there is another factor, convenience, that my professor did not account for. I own a Tesla and the primary selling point… OK it was acceleration… But the secondary selling point was never having to go to a gas station again when I am just barely going to make the meeting and forgot to fill my gas tank the night before.
https://en.wikipedia.org/wiki/Syntin
Edit: Soyuz U2 (Syntin version) launched 72!! rockets. Then they reverted back.
Most of the energy you buy with a tank of gas goes to heat the air around and behind the car as you drive.
In other words: even when you take conversion into account, energy density (both by weight and volume) is better in gasoline than battery.
(I love BEV, and I see it will win over most of the market, but gas wins on energy density)
Curious example since that's one of the drawbacks of an EV. If you forgot to fill the gas tank and have to stop, you'll be 5 minutes late. But if you forgot to charge the EV, now you're looking at several hours late (or give up and call a cab).
i’ll address a couple of things though… First, since you plug-in every day at home it is very very rare for me to forget. Second, the total available range is still close to my old gas cars which means I need to have forgotten for many days in a row which in the last nine months has never happened.
BUT, I did say that I was low on energy on a day I needed to make a long drive…
Backstory was I was intentionally draining my battery over a period of about a week without charging (trying to recalibrate the gauges... very rare to do).
In the morning on a day I needed to make a three hour round-trip drive I realized I was at 20% power.
So I hightailed it to the nearest Tesla supercharger, plugged in, pulled out my laptop (I'm sitting on a giant battery... powering a MacBook is no issue) to get some work done, and 20 minutes later I was at 80% (enough for 200 miles - or my entire round trip).
So the power issue was caused semi-intentionally and entirely my fault but also it took very little time to solve it. It would be a bigger issue for somebody who isn’t near a supercharger (and no 220 line at home as they'll go 0->full overnight) but again it is very very easy to remember to plug-in at night and many/most people would generally need to forget to charge for at least three or four days before it becomes an issue.
If the range is so huge, I see it might not be an issue.
We have a Fiat 500e, so forgetting to charge overnight (or if the timer didn't go on as intended for whatever reason) means a guaranteed crisis in the morning as there's no way to get to work.
It doesn't work like that unfortunately. Unless you're using a low power charger charging time is limited by the C rating of the battery and that is independent of how big your battery is.
That's not what they're saying, this is about space required to get the same capacity.
The relevant quote is "meaning that energy density at the pack level should compensate". What's going on is that the chemistry energy density is lower, so you need bigger batteries to get the same capacity (i.e. range). Normally this means you would need more space in your vehicle to get the same range, however you need less cooling so you save some space there so the overall space usage of the battery system ends up about the same.
Possibly building LFP batteries as well now that the patents have expired. The reason CATL has such a lead on LFP manufacturing is that they had a free license for using LFP patents for domestic consumption in China.
For consumers (at least in my own experience) there is a range threshold that, once surpassed, means I almost never have to worry about fill ups again. So the Every day convenience outweighs the once or twice a year inconvenience of longer “fill ups“ vs gas for extended drives.
I bought mine because I hate little annoyances like having to remember/go to the gas station and fill up periodically.
For long-haul trucking though Tesla's benefits would be in automation/assisted driving, not in electrification. Short of some sort of carbon credits/regulations it’s difficult to imagine widespread adoption of a technology that has more downtime and higher initial costs than a previous technology.
The stop/start of small truck deliveries (and subsequent energy recapture) makes sense but for long-haul I can’t see it feasible until the battery energy densities jump by a sizable margin without a corresponding increase in price.
And at that point there's still few financial advantages of electrification I can think of... what am I missing there?
Perhaps in super cold climates it starts getting silly though
There was a part of Battery Day where they explain their approach to battery chemistry, here is the slide: https://cdn.motor1.com/images/mgl/JvxPA/s1/2020-tesla-shareh...
They say in the title "All Standard Range Teslas", but only the Model 3 has a standard range version and they're still like 2-3 years away from their compact/25K car.
If other parts of the car production are the constraint, stick with the big batteries and high prices.
LFP is just for lower range vehicles where the advantages of LFP outweigh the decreased energy density.
https://i.imgur.com/ycylklk.jpeg
I say this because there’s another article from the New York Times about Tesla‘s earnings on HN's front page and this one from Ars is more technical, more straightforwardly written, and much less hyperbolic than the NYT version. (This one focuses on earnings and potential major changes that could impact the bottom line versus New York Times spends 50% of their article discussing government inquiries into autopilot.)
I can't update the title but would recommend this article over the New York Times one.
The title has changed since I posted.
Will be replacing the lead acid in my RV soon with LFP's, it really a no brainer.
1. https://www.amazon.com/dp/B08FMTRYPT
2. https://www.youtube.com/watch?v=xBonGQe363g
https://pushevs.com/2021/01/10/guoxuan-unveils-a-cobalt-free...
Without compromising on cost.
I just bought a GoLabs Portable Power Station https://gotrax.com/products/golabs-r300-portable-powerstatio...
Pretty much all the good Solar Panel/Wind Power Stations use LifePo4.
Check out the bestsellers in outdoor generators:
https://www.amazon.ca/gp/bestsellers/lawn-garden/6257187011/...
I'm sure there are benefits, but I don't know much about batteries to understand why you'd make that tradeoff.
With Lithium iron phosphate batteries the charge cycles are in the 5000-9000 cycle range.
TLDR: They can be discharged significantly more times than conventional lead acid batteries.
The LFP battery will also last for ~5000 cycles, after which it'll still have ~80% capacity, and thus is still valuable. Lead acid only has a life of 500~1200 cycles. In other words: you'll have replaced the lead acid battery 4~10 times before you need to replace the LFP.
IIRC, lead acid has a higher voltage drop when drawing a lot of current. Meaning that with LFP you can power larger loads.
Taken together, for most use-cases, the lifetime TCO of LFP is better than lead acid.
What happens if you keep using the LFP battery after that? Does the capacity continue to fall to zero, or is there some point it levels off and you can use it indefinitely after that if you don't mind the reduced capacity?
There is a chart for 3k cycles here: https://www.ctechigroup.com/deep-cycle-life-lifepo4-cell-3-2...
Peukerts law does not really apply to lithiums [1] so with lead acid your capacity is greatly reduced if you do high amp draws.
You can really only use 50% of lead acid capacity without significantly effecting their lifetime, so most people cut the capacity in half when discussing, lithium can be run to 80% without issue and really even 100% with minimal loss and LFP's have much greater cycle than lead anyway so you probably pay less in the long run with a LFP than buying multiple lead.
LFP hold their voltage pretty consistently right up to the end of the discharge cycle while lead acid will drop significantly, this increases amp draw and has other negative effects (dimming light etc). The low internal resistance makes them pretty stiff voltage sources.
LFP accept bulk charge much longer before hitting absorb than lead so they can be charged much faster, this helps when charging from a generator as you don't have to run it as long to get full charge. Also you don't really have to worry about partial charging, where as with lead you want to do a full absorb regularly to keep their capacity up.
At least half the wieght.
Top tier lead AGM like Lifelines are basically the same price, I have these in my RV now and are a out 7 years old and now need to be replaced due to not holding a charge. Lifelines are considered gold standard and have high charge and discharge capability for lead acid, but LFP still blow them away, so no reason to go that route again.
Those cheap lead acids are not going to be decent deep cycle and will be wet cells, so will have off gassing and cause corrosion. AGM solve that and good deep cycle AGM's are not cheap, see Lifeline, Trojan etc. You can get relatively cheep "golf cart" batteries but again wet cells that need water checked and have to vented properly.
There are downsides to LFP:
More complicated, they need a BMS to protect from over and under charge, the BMS has current limits due to using FETs to switch on/off, so most of the drop in replacements can only do 100 amp continuous with short burst of say 300 amps. So they are not great engine starting batteries. You can run in parallel to get more current capacity obviously. BMS is a full microcontroller with high current disconnect so much more to go wrong, although some have bluetooth with an app to monitor individual cells etc.
They can't be charged below freezing without damage, so most BMS have low temp disconnect to protect against that. Also there overall temp range is narrower than good lead acid, my lifeline are rated -40f to 160f I believe. Lead acid are simple tough and reliable.
1. https://en.wikipedia.org/wiki/Peukert%27s_law
I have first hand knowledge where at the small and medium scale, Chinese manufacturers will happily knock off major brands and steal technology to make products, and as a non-Chinese IP owner you have very little recourse. Is this situation still how it works for key IP from major companies or if you're (e.g.) Tesla and you had a patent on battery technology, could you realistically enforce it in China?
There are some old quotes from Elon Musk about Space X just keeping stuff secret rather than patenting it because otherwise he'd be just giving it away to his major competitor in China: https://www.businessinsider.com/elon-musk-patents-2012-11?r=...
And apparently much less explodey.
This way pouch cells outperform hard cased ones so much on capacity, but in reality it's a big delusion as you still have to put structure to hold cells in place — and you can't do it with flimsy, paper thin casings.
EVs are insanely awesome though. I'm leasing a 2019 Bolt and after a month or so it's the best car I've ever driven. EV torque is a blast. With the type of driving I do I'm able to get by on a Type I charger at my apartment and a rare visit to a public charging station. I think one-pedal mode helps because I'm barely ever using the brakes.
They won't be top of the line, but still useful and profitable, given that the best cells will be taken up by megacorps for the foreseeable future.
You don't need the highest capacity stuff for power tools and home solar/wind storage, for example.
The machinery is quite expensive, however.