Tell HN: I think I found Toyota's battery

[scythe]

Recently there was a thread about a "breakthrough" in battery technology at Toyota.

https://news.ycombinator.com/item?id=36585327

Toyota has been putting out PR puff pieces about their "solid-state" (solid-electrolyte) batteries for years, but this story was unique in that it had a quote from Keiji Kaita, who holds some high-level role at Toyota. Anyway, I didn't think much of it, because there was no paper referenced in the Guardian article, which seemed to be the original source.

But while reading about something else, I came across the paper "A near dimensionally invariable high-capacity positive electrode material", published in Nature Materials last December:

https://www.nature.com/articles/s41563-022-01421-z

This paper, reporting a cathode that has very little (much less than normal) change in size or shape when charged and discharged, claims reversible storage with a solid electrolyte. It stands to reason that dimensional stability of the cathode is necessary for interfacing with a solid electrolyte, since if it swells and shrinks, it will probably detach from the electrolyte, and possibly damage it further.

Looking at the affiliations of some of the authors we see a number of contributors from the "Lithium Ion Battery Technology and Evaluation Center (LIBTEC)". A web search about LIBTEC leads to several articles from 2018:

https://www.cnet.com/roadshow/news/toyota-nissan-honda-libte...

which state that Toyota, along with Nissan, Honda and Panasonic (Tesla's major collaborator), have established this consortium to work on solid-electrolyte batteries as of five years ago.

So what does this thing look like? It's a vanadium–titanium cathode, Li8Ti2V4O14. Titanium is common; vanadium technically has a higher crustal abundance than nickel, but it tends to be spread across low-quality deposits, so production is low right now. A review considering the resource outlook for V-based batteries [1] was guardedly optimistic. 750 Wh/kg is great. Vanadium cathodes historically had a problem with high dimensional instability, but it appears that cocrystallization with titanium may have fixed that, and the weird properties of vanadium became an advantage in compensating for Li+ influx/efflux.

The use of a sulfide electrolyte pours doubt on claims of safety, though. It's reasonably likely that if water were to come into contact with the electrolyte, it could release highly toxic hydrogen sulfide gas.

Also, since the battery was developed in collaboration with other major automakers (and funded by the Japanese government), it's somewhat questionable to think it would give Toyota a major advantage in the EV race. But for the Japanese economy, which has been rather slow lately, it could be a boost.

1: https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10....

[canoebuilder]

> 750 Wh/kg is great.

To put it mildly.

Energy density in the current leaders in that category, lithium ion batteries, 250-270 wh/kg. So, provided a similar or better ratio of watt-hours to unit of volume, we’re basically looking at tripling the energy storage of EVs or significant weight reduction, in the ideal scenario of this design being a safe and cost effective replacement for current batteries.

[dangus]

I think for the EV skeptics it’s easy to forget how fast battery chemistry has been evolving. There’s an common assumption that the EV status quo of 300 mile range at barely-affordable prices will continue forever, and therefore with all the woes surrounding charging and bad weather affecting range, EVs are dead in the water.

Ten years ago $30k got you 75 miles of range out of a Nissan Leaf. Fast forward to present day and you will spend less money before adjusting for inflation and get 259 miles of range in the same class of vehicle (Chevy Bolt EV).

When many automakers say they will only sell EVs by ~2035, it sounds a bit far-fetched, but in the context of the past 10 years it’s hard to deny the high probability that gasoline vehicles will make basically no sense by the 2030s on the basis of value.

Gasoline cars will simply cost more to own, end of story.

[condour75]

According to a quick googling, this would be enough density for for short range commuter aircraft to become viable.

https://theicct.org/aviation-global-expecting-electric-jul22...

[jillesvangurp]

Actually CATL announced a 500 wh/kg battery a few months ago. Solid state and aimed at the aviation market. Shipping this year apparently. There are a few other companies targeting that market. For cars, much lower density sodium ion and lfp batteries are what they are producing in volume. Sodium ion especially is becoming popular for the kind of cheap/modestly priced cars Toyota is famous for mass producing.

Those higher density batteries are great when cost doesn't matter (like in the aviation market) but cost is the only variable that matters when it comes to mass producing electrical vehicles. The game is not who can build the most ridiculous car for 100K but who can produce the most useful car for 10K. Toyota is going to have their ass handed to them very soon in that market unless they get their act together.

People that obsess over range are missing a few important points. With fast charge times, range matters less, and if your car is fully charged every morning, the times when you need to charge before you get home reduce to the rare occasions when you actually drive the cars maximum range in a single day. Which for the average driver isn't that often. The point of having a large battery is reducing those occasions to almost zero. If that matters to you, just spend more money and you'll be fine. There's no need for new batteries for this.

The point of a having a smaller battery is that the few times per year that you have to stop to fast charge them isn't worth the price difference in terms of time spent. Especially when that time is basically only around 30-40 minutes. Companies that operate vehicle fleets get this. They get the battery size they need, not the largest one. That's why most electrical vans have batteries that aren't bigger than those in cars. Smaller even sometimes. Smaller battery means more useful load. The reduced range is fine.

Toyota doesn't need a new science fiction battery, it needs battery production infrastructure producing batteries by the twh per year. Nothing else is going to enable them to mass produce cars at the same rate they are producing ICE cars. They are not building those factories yet. I'm not sure what they are waiting for at this point. But they are running out of time. Cheap EVs are going to be on the market pretty soon. They already are on the market in China. The main constraint for that is battery production volume. Some companies are investing in that as fast as they can; Toyota so far isn't.

[hinkley]

For mobile applications wh/kg and wh/liter both matter, and they can vary independently. With the titanium electrode you’ve got a lighter battery per unit of volume. That said, a vehicle battery has to propel itself, so a lighter battery requires less capacity and thus a bit less volume.

[AtlasBarfed]

It's within range of some of the sulfur techs I've seen in papers though. The sulfur techs appear safer and more abundant.

Both aren't commercialized either... For some reason, I suspect sulfur techs will go to market sooner.

What is apparent is that in 10 years battery tech will be in a much better place than it is now: 2x - 3x the density, safer, 1/2 or less the (inflation adjusted) cost. Sure that's not Moore's law rate, but that will be nonetheless revolutionary.

240 wh/kg has already been commercialized by Gotion in LMFP chemistry, so that's cobalt-free/nickel-free. 160 wh/kg sodium ion should utterly revolutionize city transportation, you don't even need lithium for that and it should be a 200-300 mile car (EPA not WLTP) or better.

IMO most car companies are probably chasing the high density LMFP and Sodium Ion for the next 5-7 years, and leaving nickel-cobalt for things that truly need it. The issue with nickel-cobalt is that the safety systems consume so much at the pack level that 200+ wh/kg LFP is basically the same density. And Gotion's 240 wh/kg will probably be functionally more dense at Cell-to-Pack densities as well as cheaper.

We still need that high density breakthough through, the US Market will probably demand 400 mile ranges (see Tesla range "fraud" story) for true mass market stupid driver adoption, especially for all those men that just have to drive a full size pickup and then buy things for it to tow.

[alostpuppy]

Out of curiosity, What is the wh/kg for petrol?

[oblio]

At that energy density, can't they just wrap the entire smaller battery in 2 layers of ceramic and steel or something and just side-step the entire safety discussion OP is mentioning?

Yes, I know it's probably a silly solution :-)

[morepork]

Because weight affects range, you could keep the same amount of energy and increase range at the same time as the battery would only weigh 1/3 as much and be maybe 400kg lighter

[bboygravity]

400 Wh / kg is the threshold that makes VTOL high altitude (20+ km) electric aircraft feasible according to Elon Musk in one of his interviews (from memory, I might have some of that wrong).

Advantages: no runways needed at airports, can get back some energy on the way down through regenerative braking, more efficient propulsion and less air resistance at higher altitude (electric motors don't need oxygen to function), no pollution from combustion.

Sounds amazing.

[DiabloD3]

Hey scythe, write a blog abut this.

This seems like semi-decent conjecture that'd get a lot of pull with the electric car crowd on the Fediverse, and you'd get a fair number of eyeballs pointed in the same direction.

[skrebbel]

A Tell HN is basically a blog post right? Permalink, comments, it’s got it all. There’s even an RSS feed.

[alex7734]

> it could release highly toxic hydrogen sulfide gas.

How bad is it in real world conditions? Because from what I'm reading it's not the "it makes you sick" kind of toxic, but rather the "it kills you in seconds" kind of toxic.

[snowwrestler]

There’s no way to concentrate energy without creating some danger. Gasoline is quite dangerous but we drive around with tanks full of it now. Natural gas and high-amp electricity are dangerous but we have them coming into many houses.

So I would propose the question shouldn’t necessarily be, “how bad is the worst-case scenario”—it’s pretty bad for all energy sources. I think a better question is “how reliably and efficiently can we prevent or mitigate the dangers.” That will go a long way toward determining its commercial viability.

[runnerup]

Current lead acid batteries can do this as well. Smells awful and pretty unsafe situation. H2S is quite dangerous but it’s rare that they’d create an IDLH situation as long as there’s a bit of breeze.

[bell-cot]

MSDS for H2S - https://www.airgas.com/msds/001029.pdf

The Occupational Exposure limits are fairly low 'ppm' numbers, and LC50 is 712ppm for 1 hour. (That is the concentration at which 50% of the exposed rats died.)

[hadlock]

Someone else pointed out LD50 is ~700ppm

It's unlikely you'd be exposed to this level for any period of time unless the battery ruptured into the car, underwater, with the windows up, in which case you have bigger problems. You're unlikely to to see 700ppm in an outdoor situation like a car wreck or battery malfunction on the highway during a rainstorm. Atmospheric CO2 is about 450ppm for comparison.

Ammonia is a superior refrigerant (widely used in industrial circles, and causes no ozone depletion, is biodegradable, etc) but not used in residential applications because it's highly toxic if there's a catastrophic seal failure and not vented outside, despite the fact that humans are very efficient at smelling even the slightest ammonia leak.

[_a_a_a_]

HS is funny stuff. Does nothing then zap, ur dead.

UK figures for safe working concentration in air, from memory, hydrogen cyanide 11ppm, hydrogen sulphide 10ppm

[npsomaratna]

I remember synthesizing H2S in high school (for chemistry practicals, I think). I made the mistake of attempting to smell it. This was for a fraction of a second—but during that time, I could feel the individual bubbles of gas entering my nose; and I almost passed out.

[lstodd]

Rotten eggs smell is just about everything you can get from this kind of experiment.

Now if they scale it up. but at any scale that makes sense economically you can get suffocated by just about any gas you can think of. Like helium or hydrogen.

[jncfhnb]

Depending on concentrations required for consequences a smelly gas is much safer than something like CO

[jacquesm]

That's an interesting find and some nice sleuthing you did there.

[imaginebit]

I remain an EV skeptic because of the flammable electrolyte in Li batteries. They did a good job of protecting the battery pack and managing possible thermal runaway. But reading some EV crash news, I noticed one aspect of EV fire is particularly frightening: the speed of the fire and thoroughness of the fire burning. If the crash is severe enough to cause fire, it's usually within 1 or 2 minutes before the fire reaches the driver seat and then it'll burn it down to skeleton and the firefighters can only stand by and wait for it to burn out.

[megaman821]

This will be neat if it works but really there isn't going to be a huge market for 500+ mile cars vs the cost savings of getting a 300-400 mile car. The exception might be road-trippers and people who do a lot of towing but I suspect that is a much smaller population than people tend to think.

[ultrarunner]

If it could only reduce the weight of current EVs that would be a win. Most electric vehicles weight 1000 lbs or more than their ICE counterparts, and in the extreme case of the Hummer, the total weight is over 9000 lbs.

Vehicles seem to be continuously ballooning in size, so whether that continues or eventual legislation forces more reasonable sizes, higher energy density would be very welcome.

[topper-123]

What are you on? Having battery with 3x battery capacity will be an absolute game changer. This will do a lot of good, if it gets into production. For one thing, it will make EVs competitive with diesel, which will be s huge win for getting us of oil.

[molsongolden]

The additional capacity might be wanted in cold climates. The massive range drop when running the cabin heater plus slow charging in cold environments definitely makes me pause when considering an EV.

[achiang]

Real world usage is you only get to use ~70% of the stated range on a road trip, so we're really talking about 350 miles of range, which is, as you say, what most people actually want.

Why 70%? You obviously don't run the battery to zero, 10% is a common amount of buffer to leave. And then when you DC fast charge, the rate of charging drops dramatically around 80%, so people don't charge to full.

These are for ideal conditions, add in any sort of weather and the range drops again as you run a heater, etc.

Living in the Bay Area, driving to Tahoe in the winter without a mandatory recharge should be the gold standard.

It's not an unusual use case, "only" about 180 miles, and yet there aren't any EVs that can do it confidently because going uphill in the cold with aerodynamic-destroying ski rack is really hard.

A car with 500 miles of fair-weather range could probably do it?

[jackmott42]

Just people who go on road trips with 2 or more mountain bikes need this. This is not theoretical, a Model Y has its range ruined with 2 or more mountain bikes attached to the exterior. Like ~140 miles max on our trip with 4 mountain bikes. And then you tend to go to more remote areas so that makes it even worse.

So yes, our family is eagerly awaiting a 500 mile range ev

[qball]

A gasoline car can charge from 0% to 100% of its range in 5 minutes. It usually takes longer to take the slight detour and line the car up with the charge port than it does to fully charge the car. Recharging this kind of car does not damage its most expensive part nor does its fuel tank shrink.

The newest electric cars take a half hour to do this (a non-trivial amount of time) and only go about 2/3rds as far (less on the highway), so if you actually want to go somewhere you're taking on about an extra hour of charging for 6 hours of driving. Recharging this kind of car damages its most expensive part- the fuel tank- and it shrinks every time you charge it (whether quickly or slowly).

Now, if the car had 1600 miles of range, then a half-hour charge time and the slow shrinkage of its gas tank is more acceptable because you're getting approximately the same rate of recharge per minute (as it would be if the 200-mile range electric cars charged as fast as a gas car does). With a range or charge time like that, the other inherent disadvantages to electric cars are muted to a massive degree (a 20% range degradation isn't as big a deal for a car that can still go 1200 miles, and a 30% range reduction in cold months isn't as big a deal if the car could be charged in 3 minutes).

But neither of those things are currently true, and that's in large part why these kinds of cars don't really sell unless they're known to be rolling gimmicks or transformative in other ways (the electric trucks that let you run power tools off their batteries are the best example of this). Which is why Tesla's cars are the way that they are, and why every other major manufacturer who doesn't have a good idea of how to sell their inferior cars take the "look, we can do a massive screen in our car too just like Tesla" approach (and fail specifically because they aren't Tesla), or they just keep developing really good gas cars (an approach currently favored by the Japanese companies).

[asdff]

People like having extra capacity even if they scarcely use that capacity. This is why the F150 is the best selling car in America. Not to mention its better in general to have extra battery capacity than you might reasonably need today, as it will degrade with age, or temperature.

[benrapscallion]

If I had asked people what they wanted, they would have said a faster horse. -Henry Ford

This is analogous to how people thought nobody would need a 100 GB hard disk on their personal computer when 1 GB hard disks were the norm.

[ru552]

500+ miles means I can just charge up on the weekend and not be bothered with it during the week. I'd pay for that convenience.

[lelandbatey]

Since it's a bit more than a doubling of energy density, it's less that you can get a 500+ mile car and more that you can drop the price & weight of a 300-400 mile car. Imagine cutting the weight of an EV battery by 500 pounds while maintaining its current capacity. All that weight savings will probably get you some additional range, and save you on cost of materials, meaning you could cut the battery down a bit more to save even more on materials while saving a bit more weight. All told, you could have the exact same EV, but manufacturing the battery just got ~50% cheaper! That's what's exciting about this as a possibility, not 500+ mile cars.

[MisterBastahrd]

I think you'll find that for many people, EVs are a non-starter unless they can mimic the same travel timelines you can get from a combustion engine. 500 miles is very close to what they'd be looking for.

[causi]

Also people who don't do all their driving in the city. That 250-mile battery shrinks a lot when your whole trip is at 80mph.

[VanillaCafe]

There are a lot of real world caveats that go into those range estimates. I just took my long range Tesla Model Y with an advertised 326 mile range on a multi-day road trip and I was stopping to charge about every 100 miles. I would love to get something with 3x the advertised range.

[lostlogin]

> I suspect that is a much smaller population than people tend to think.

Pickup truck owners will die on that hill.

[canoebuilder]

Given an innovation of this sort, there is not a single area of application, extending the range of electric cars. You could also make lighter weight electric cars. Which would have their merits.

Think of the whole spectrum of EVs, lighter weight e-bikes, scooters, skateboards, or long range e-bikes. Electric aircraft start to become feasible.

Much more flight time out of your toy drone, multi-day battery life for your phone or laptop.

Energy storage in off grid setups becomes simpler, or more capacity in the same space.

Etc. etc.

All that provided this new design could function as a more or less slot in replacement, or better, for current lithium batteries in terms of manufacturing, cost, and what not.

[Hankenstein2]

Agreed on the small market, what would move the needle is if it re-charged much more quickly than current batteries.

EV owners really only want 500+ miles because charging the battery takes so long. Charging infrastructure is already changing and becoming more available so charging speed will be the real quest

[7speter]

Even if there is no demand for 500 mile range cars, solid state batteries are supposed to be twice the density of current batteries so a 3-400 mile car would still be something like 25% lighter than they would be with current batteries.

[carabiner]

? Range is how often you need to recharge. For people like in apartments without home charging, this is huge, especially since homes are so unaffordable now.

[lowbloodsugar]

More energy doesn't mean longer range for me. It means I can pass other cars and drive the speed I want when I'm up in the mountains, instead of having to eke out every last mile. If I get 8MPG in my mustang because I'm enjoying my drive, there are gas stations every few miles, even in state parks. EVs burn "gas" just as quick if you drive them the same way, but there's no charger for 60 miles. The KIA EV6 GT just can't make use of its 580hp in the places I'd like to enjoy it because it only has 200 mile range to start with.

[richardw]

Trucks, buses, planes, boats (eg ferries), smaller lighter cars, bikes, drones. Everything can benefit from smaller and lighter, or longer charge.

[Bud]

Americans don't buy cars anymore, though; not really. They buy ludicrous gigantic heavy pickups and SUVs. So what we're really talking about is getting decent range into oversized pickups that their owners want to accelerate like sports cars and still have a nice air-conditioned interior even when it's 150 degrees on the pavement due to climate change.

[kragen]

a solid sulfide electrolyte isn't necessarily fatal to claims of safety

i can't tell which sulfide it is from the nature link, but many metal sulfides release hydrogen sulfide only very slowly in contact with water, sometimes over geological timescales. it only becomes a problem if you, say, grind them up and mix the finely divided powder (which is also often pyrophoric!) into sheetrock

consider for example https://en.wikipedia.org/wiki/Chalcocite https://en.wikipedia.org/wiki/Covellite https://en.wikipedia.org/wiki/Pyrite https://en.wikipedia.org/wiki/Galena https://en.wikipedia.org/wiki/Sphalerite https://en.wikipedia.org/wiki/Mercury_sulfide https://en.wikipedia.org/wiki/Millerite https://en.wikipedia.org/wiki/Realgar https://en.wikipedia.org/wiki/Orpiment https://en.wikipedia.org/wiki/Stibnite and https://en.wikipedia.org/wiki/Molybdenite are all relatively stable metal sulfide minerals which don't offgas hydrogen sulfide fast enough to pose a significant hazard (or at all; many oxidize to sulfates instead)

even https://en.wikipedia.org/wiki/Calcium_sulfide is relatively innocuous aside from the bad smell, and https://en.wikipedia.org/wiki/Sodium_sulfide is routinely handled by photographers and dyers despite the hazard. you have to get into the exotics like https://en.wikipedia.org/wiki/Lithium_sulfide before metal sulfides really get scary

[andrewflnr]

There are definitely a lot of lithium ions floating around, so lithium sulfide seems possible, as part of a failure cascade if nothing else.