Mainstream electric vehicles have been around for more than a decade now, and they’re gradually disproving a lot of the bluster and misinformation levied against them. Still, every so often, an EV owner somewhere is given a truly shocking quote for a battery replacement. That leads to detractors frothing at the mouth that batteries suck and EVs will never work. That’s unlikely to stop, of course, but VW reckons solid-state batteries could help salve the issue, at least.
VW is just one of many automakers exploring the possibilities for solid-state batteries in future. The technology promises higher energy density than existing batteries, along with less fire risk by the elimination of flammable electrolytes. Solid state batteries, if mastered, could also potentially be more resilient to charge cycling, giving them a longer useful life with less degradation. It’s in this last area that a solid-state battery company linked to VW thinks it may have made a breakthrough.
QuantumScape is a California-based company dedicated to developing solid-state batteries. The company recently provided a prototype to PowerCo, a European company established by VW to handle battery technology and manufacturing. In testing by PowerCo, the prototype battery was able to retain 95% of its original capacity after 1,000 charge cycles. That’s an excellent achievement, given that VW has quoted industry targets of 20% range loss after just 700 cycles. The cell also met all requirements as far as fast charging, self-discharge rates, and safety were concerned.
If these batteries were used in an automotive pack with a range of 500-600 kilometers, then 1,000 charge cycles would cover driving a full 500,000 km. Translated into U.S. units, for an EV with roughly 310 to 370 miles of range, that many charge cycles would rack up over 310,000 miles on the odometer, with 95% of the original capacity still usable after that time. That’s more than most cars ever achieve in their lifetime. Of course, this is an idealized number, assuming 1,000 full charge cycles with maximum range achieved each time. Nonetheless, it suggests the battery technology could have excellent longevity beyond what is currently achievable in today’s EVs.
How Solid State Batteries Work
Solid-state batteries eschew the liquid or gel electrolyte used in typical lithium-ion cells for an all-solid construction. We should probably do a full article on these batteries, but in short, solid-state battery technology could enable the use of lithium metal as an anode material, which stores more energy than the anode materials used in current batteries.
In conventional lithium-ion cells, metallic lithium can react with the liquid electrolyte, or form dendrites that pierce the cell separator and cause a short circuit and subsequent failure. The idea of a solid-state battery is to eliminate the liquid electrolyte, stopping any side reactions with the metallic lithium, while using a solid-state (often ceramic) separator that stops dendrites from killing the battery. The challenge has been to find a solid-state separator material that can actually prevent dendrite formation, which QuantumScape believes it has achieved.
By enabling the use of a metallic lithium anode, the solid-state battery can store more energy for the same weight, promising better energy density. The scope of improvement is huge; solid-state batteries could be potentially up to two or three times more energy-dense than conventional lithium-ion cells. Eliminating this flammable liquid electrolyte also cuts the risk of fire and allows faster charging thanks to the lower risk of ignition due to overheating.
The technology is actively being pursued by many companies, but issues around robustness and reliability remain. In many cases, the growth of lithium dendrites inside solid-state cells destroys the pack in short order. Thus, despite great energy density, many designs have suffered failures in a short number of charge cycles. However, it appears that QuantumScape may have found a way to solve this particular issue.
Don’t expect to see the cells in production vehicles any time soon, however. The cells are still prototypes, though QuantumScape states its 24-layer test cell already corresponds to the design planned for series production. Regardless, figuring out a way to produce them en masse is still a big job, and building the factories is another one. Many automakers are already struggling to spin up enough battery production for conventional cells as it is.
With that said, though, if QuantumScape is able to figure out reliable solid-state cells and the right manufacturing process, there’s great potential. Volkswagen or another automaker could attempt to skip over ramping up factories with conventional batteries and instead invest big in solid-state production. If the cells hold up in real-world conditions and can be made affordable, their greater energy density would be a huge game-changer for any EVs that use them. It would be possible to build EVs with much greater range than the competition, or conversely, with similar range but huge weight savings.
In any case, those involved are getting excited with the latest developments. “While we have more work to do to bring this technology to market, we are not aware of any other automotive-format lithium-metal battery that has shown such high discharge energy retention over a comparable cycle count under similar conditions,” said Jagdeep Singh, CEO of QuantumScape. “We’re excited to be working closely with the Volkswagen Group and PowerCo to industrialize this technology and bring it to market as quickly as possible.”
Time will tell whether Volkswagen’s investment in PowerCo and QuantumScape will pay off. The results quoted are promising, and it could put the company well out in the lead of rivals stuck using older traditional cells. It’s an exciting time in the battery world, that’s for sure.
Image credits: Volkswagen, QuantumScape
You people are amazing. The depth & breadth of knowledge about battery tech in just this comment section is eye-opening.
Autopian certainly does entertain and educate
First of all, congratulations on having this years best tight rope EV related article so far.
Notice the first word in each of these sentences:
-thinks it may have made a breakthrough.
-could offer far greater energy densities
-can react with the liquid electrolyte
It is quite the balancing act.
Secondly, it is quite interesting that this is VW related, since they are one of the very few companies that still see extensive battery degradation issues on new cars.
Toyota is working on solid state batteries too and is on track to be the first to put them on the market.
Actually kind of funny that both of them (Toyota and VAG) are very reluctent when it comes to releasing new EV models.
I am aware that VAG appears to offer a lot of EV models, but they also, appear to, spend much more money fighting EV’s in the political arena than they do in R&D of their EV models.
They are:
a) absolutly correct in awaiting solid state batteries
or
b) corrupt asholes (remember diesel gate)
I think the battery density with solid state is the biggest Boon to toyota as their issue with Lithium is capacity. They can produce a EV/Hybrid with solid state batteries using less materials so they will be able to make more cars with the same amount of materials. Also Weight of the cars go down , cargo room goes up, and maybe prices go down? Seems like with solid state batteries everyone wins. I’m sure tesla or lucid or someone will cram a 1,500 lb solid state battery in a car to boast some stupid high range numbers for bragging rights but it seems like the main benefit of solid state is it will be cheaper, lighter , smaller, and if this study is correct more durable.
So how did they solve the mechanical separation issue between the annode and cathode? That, as far as I know, has been the Achilles heel of solid state batteries.
I’ve had a few hundred bucks invested in these guys for a couple years now. Hopefully it takes off!
That mockup solid state battery looks an awful lot like the famous samsung exploding batteries, or like the swelling fire catching apple ones from the macbook pro
https://www.notebookcheck.net/fileadmin/Notebooks/News/_nc3/samsung_sdi_cylindrical_battery75.jpg
Just saying
That’s because that’s what every soft case lithium battery looks like.
so thats a soft case solid state battery …. not very solid after all isn’t it?
Sounds great, just like all of the other lab-only proof-of-concept solid state batteries. Until someone manages to do this repeatably, at scale, solid state batteries remain in the same category as flying cars: always five years away.
Yeah, you could replace the date in this article with “2014” and it would be the same.
I would love for someone to make solid state batteries work, and given that there are hundreds of companies that would throw billions of dollars at you to come up with a reliable, workable, scalable design, I think the incentives are there. And yet we remain still in the prototype stage.
A couple of other very important things to note, they also:
None of these advancements, along with almost zero battery degradation that you mention in the story, should not go unmentioned. More information on their list of recent achievements can be found on QuantumScape’s website.
Great- but this same story has been printed (just change the names) every year for at least a decade. Lab tests, with specially made prototypes are not remotely the same thing as actual industrial adoption. There are many billions of dollars to be made on better battery tech like solid state, but the fact that no one is claiming that $$$ yet leaves me skeptical it will available in the near term.
Uhm, I hate to bring this up, but did Volkswagen perform their own tests?
I thought this when I saw the headline. A third party performed testing on the battery prototype, because yeah, we need to be suspicious for sure. However who owns the testing company?
From the article:
“The company recently provided a prototype to PowerCo, a European company established by VW to handle battery technology and manufacturing. In testing by PowerCo, the prototype battery was able to retain 95% of its original capacity after 1,000 charge cycles”
This was VW replicating the results from QuantumScope.
I don’t know why they’d want to lie about this one (either way it’s still going to be quite a few years before these make it into cars). I imagine if the tests had been a failure they would have steered far from the press and gone back to the drawing board.
Misleading headline. Either you don’t understand EV’s or are intentionally crafting click bait titles. Battery pack longevity is a factor of battery pack size. The bigger the KW-hr the pack, the less cycles it will take to reach 300,000 miles, so the metric you use it not irrelevant. It would be equally silly to say that a gasoline powered car is very efficient because it can go 1000 miles on a single fill up without mentioning the fuel tank size or gas mileage it gets. Cycle count is the only thing that matters and in fact is already sufficient for pure EV’s. Even if a tesla loses 20% capacity at 1000 cycles, it will already have over 300,000 on odometer. Where solid state batteries or other high cycle batteries become a game changer is in hybrids and plug in hybrids where high cycle counts damage the batteries surprisingly fast. The present limitation for full EV batteries is not cycle count but cost and capacity per unit weight and volume. If you could make a battery that is 200 kwhr the same size and cost as today’s 100kwhr then you could double the range of the average EV. So take a EV with a 300 mile range that would now have a 600 mile range with a better battery. It would be a game changer. And incidentally, even if it had a 500 cycle lifespan, it wouldn’t matter, because 500 charges at 600 miles would give the car a 300,000 mile lifespan.
Came here to say something similar to your points. Degradation is only one variable for solid state batteries. Others are, as you mentioned, cost per kilowatt/hour, weight and volume.
Let’s say for the sake of argument solid state batteries win for safety (less propensity for thermal runaway). QuantumScape and other proponents still must show the energy density is equal to or greater than liquid batteries for most or every other unit measure one choses.
Interesting that PowerCo and QuantumScape focus their marketing arm-waving on charge/discharge cycles. Although it’s early days, that may mean they have not found an energy density or cost advantage to their technology.
To be clear, I’m not anti-EV or solid state batteries. To me, the PowerCo and/or QuantumScape source material reads like something one or both would send to potential investors.
That was discussed in the article. Either you don’t understand English or you’re intentionally trolling.
They based the 300000 mile number on a fairly reasonable basis of a 300-ish mile range battery, which is representative of current mainstream EVs. I don’t think it’s clickbait and I think they understood how this works just fine.
Spot on.. Not sure what tree they’re barking up, but I understood the article and see nothing deceptive about the headline..
So not tested in an actual EV, just ball park guestimating.
I hope solid states are the hero EVs need, but I’m curious how vibration testing will go without some nice electrolyte jelly to absorb shock/vibration.
Like if I someone were to take slowing down for speed bumps as a guideline not a rule, and it cracks the solid state battery, that’d be bad.
QS is far from the only start-up working on these, but has the most publicity. David Pogue did a NOVA in 2017 where he hammered nails through a pack, and cut up another one with scissors while they were connected to a volt meter.
https://www.pbs.org/wgbh/nova/video/search-for-the-super-battery/
Hopefully the production cells will have the durability, I mean that is one of the main selling points is a puncture to the cell won’t cause catastrophic fire, but with mass manufacturing and things like the ‘torn anode/folded separator’ mess that LG had on the Bolt batteries I’m wondering how resilient the production batteries will end up.
“Ready for commercial production” is the sticky wicket.
When at Economics school, a professor of mine once told me to “not believe blindly in predictions or research numbers. Anyone could put numbers that could change the world and still not lie, just to say their research is good”.
I do believe that solid state batteries will change the EV (and automotive) world. But is the kind of thing that is believable only when put in scale in real world.
Not saying that what these guys are doing is bad or not useful, but is more “investment attracting” grade than world changer right now.
That graph says they tested at .3-.5C charge/discharge? That’s not particularly high. I’m curious how that lines up with real-world average EV draw. It’s going to depend on the total pack specs but if they have to use more cells then that negates some of the usefulness. It wouldn’t matter to that kind of test but it would also ne nice to know the max discharge rate.
On average, that’s about right. It you have a 40 kWh pack of 800V, and ten 5AH battery series strings arranged in parallel, and the vehicle you are driving needs 20 kW from the batteries to hold 70 mph on the highway, that’s 2.5A per battery, or 0.25C.
I meant to say 0.5C.
Indeed. I’d like to see some high-current spikes in that testing to understand whether the batteries hold up in more realistic conditions.
1.5C continuous would probably be adequate for a low-end passenger car. You’d be able to set that as a hard limit, get 60 kW out of it with a reasonable sized pack, and never bring the battery harm.
It is also possible to run some ultracapacitors in parallel to the pack to provide the power needed for acceleration, should more power be desired.
I know next to nothing about ultracapacitors, but find them fascinating. How expensive and practical are they? Has anyone made one that could capture a rocket tow wire triggered lightning bolt, and truly capture lightning in a bottle?
I don’t have an answer to the latter question(the energy of most lightning strikes would exceed the storage capacity of an appropriately-sized capacitor bank for an EV), but per kW of peak power delivery, they’re significantly cheaper than batteries, and batteries are already cheap in this regard. Per kWh of energy storage, they are dreadfully expensive, but you shouldn’t need more than 1 kWh or so of them in parallel with the battery for most applications. This would be a $1,000-2,000 set of ultracapacitors in mass production.
Thank You! NOVA has done at least two programs on lightning, and the thought hasn’t left since. Apparently Florida is the lightning hot spot of the world, and they set up a row of rockets on a hillside, and were able to trigger several strikes- vaporizing the thin copper tow line!
https://www.pbs.org/wgbh/nova/teachers/programs/3214_02_nsn.html
That I know of the tech. to actually capture energy from a lightning strike and turn it in to usable electricity doesn’t (yet) exist.
The challenge of course is how to slow down the ‘charge’ so it can be captured.
A “maybe” feasible approach could be if you had a lightning rod that ‘attracts’ a lightning strike and intentionally discharge the strike into a sand (thermal) battery, that could allow use of thermalelectric conversion.
There will be huge losses but better than nothing…
I’m dubious of the claim that 1000 charge cycles is hundreds of thousands of miles. The use case is that people charge every night, and use them during their workday. Which sounds more like 3-5 years, before enough degradation that monitoring will be necessary.
Agreed, and it is probably worth adding some context – Lithium Iron Phosphate batteries, which are used in some Tesla models and are commonly used in vehicles with longer life requirements like commercial vehicles, are commonly quoted as having a nominal lifetime of 3000 full discharge cycles. Now whether that means 3000 cycles to 70% of new capacity or 80% or 95% I’m not sure exactly, as there are several definitions out there for when a battery is ‘end of life’ – but 1000 cycles to 95% isn’t exactly groundbreaking lifetime yet.
But if the barrier to solid state batteries is dendrite formation in the separation membrane, a successful 1000 cycle test of their solution is a strong indicator that they’re on the right track. That’s good to see.
Full discharge cycles often refers to 100%.
There is something else that must be noted. When the pack is made of thousands of cells, a small percentage of them will prove not to meet this threshold. Each series string of cells is only as good as its weakest cell, so the battery lasting 3,000 full discharge cycles according to the manufacturer does not mean the entire pack will last that many cycles, because a small number of the cells will prove defective before that cycle life is achieved.
I’m a fan of battery packs that use large AH cells as single series strings partially for this reason. Less failure points, and much easier to find and replace the defective battery holding the rest of the pack back.
Yes, the test cycles are to 100% discharged, but the quoted lifetime is ‘retains X% of new capacity for Y charge/discharge cycles’, and I’ve seen values of X used in industry literature vary – 70% is pretty universally considered ‘time to replace’ but in terms of battery chemistry advertised lifetime I’ve seen 80% and even 95% used.
Hmmm. I’m a fan of the original Tesla Model 3 architecture: 46 cells in parallel, 96 in series. The cells are like bit cells in a flash memory chip, or disk sectors on a hard drive; overprovision, and design to be resilient to failures. The bond wires to the cells are sized to be fuses; if a cell shorts the fuse blows, and it it fails open it takes itself out of the string. After the first cell failure, you loose 1/4146th of your range and 1/46th of your maximum power. If you have a second fail, you loose an additional 1/4146th of your range. The chance of the second fail being in the same row is tiny (but possible, see the Birthday Paradox). Because the cells never need to be replaced, you can use welds, solder, and glue to put it together, so it’s corrosion resistant, stiff, and lightweight. Most of the wiring is a giant PCB, so super-reliable.
Contrast this to Porsche with the Taycan: 2 cells in parallel, 196 in series. If a cell fails, you loose 1/2 your power. This is unacceptable, so the pack must be designed to be disassembleable — so lots of bolts, electrical connectors, etc. Heavy, expensive, and subject to corrosion.
Your LCD display is allowed to have up to 5 dead pixels. Can you imagine how expensive & heavy it would be if it was designed so you could swap out dead pixels?
The Tesla Model 3 showed how to correctly build a complex monstrosity of a battery, if it must be something that is next to unrepairable. This is why Tesla’s packs last upwards of half a million miles.
Battery packs by their nature are expensive and heavy, no matter what you do. My concern is, how do you make them repairable by illiterate high school dropout Bubba the mechanic down the street who doesn’t even know what a flash memory chip is, while he’s drunk? Most automobile operators do not have $XX,XXX savings in the bank to replace a bad battery pack when the car is 15 years old. They need it to be repairable for $XXX-X,XXX, or the car is basically scrap. Which is an awful thing to waste, considering the motor and inverter could probably last a half century or more.
What’s nice about hobbyist EV conversions that use a single string of LiFePO4 placed in an accessible location is that a bad cell stranding the car can be accessed, found, and diagnosed in minutes. Bolts and nordlock washers are removed in a minute or two, the bad battery is pulled out, the replacement battery is discharged down to the resting voltage of the other batteries in the car, replacement battery swapped in, nordlock washers and bolts replaced, and the car now operable once again, all in less than a few hours’ work and the cost of one replacement battery. And if you have to replace the entire pack, a hobbyist could simply order the batteries and put them in themselves, unlike a modern Tesla. No proprietary software, no electronic gremlins to sort out, ect.
I wouldn’t assume that most EV drivers are charging their vehicles every night. I charge my Leaf every two or three days depending on how much driving I have to do. If I had a modern EV with a bigger battery, I probably would charge it maybe one or two times each week.
Also, I wouldn’t assume charging from 40-60% (which is what most drivers would do if they charged every day) degrades a battery as much as charging from 10-100%. If the battery can last 1000 charge cycles going from 10-100%, it presumably can last far longer with more typical use.
It is also worth considering that the battery lasted 1000 charging cycles with only 5% degradation. If the car starts with a range of 300 miles and loses 5% of battery capacity, it can still go 285 miles. I am not sure I would worry too much about losing 15 miles of range after 1000 cycles.
They’re probably referring to charge cycles to 100% depth of discharge.
The amount of charge cycles you get varies depending upon how deep the battery is discharged. You might get 50x the cycle life to 20% DoD as you would to 100% DoD, and thus 10x the miles out of the battery pack by keeping the discharges shallow vs fully discharging them all the time.
Already, Li Ion packs in Teslas can last 300,000-500,000 miles when not abused. The real bottleneck is their shelf life. Whether you use them or not, after 10-15 years, they are degraded, even if you have 0 miles on the pack. LiFePO4 is much more tolerant to sitting for long periods without degradation, especially large format batteries by CALB and CATL.
5% degradation over 300k miles sounds more in line with well taken care of ICE vehicle. Which sounds like EVs are getting there.
But another big factor like you said is shelf life. I need a car that’s gonna last for as long as I take care of it, whether it’s being driven or is in proper storage. If there were a way to put the battery into hibernation, that would be ideal. Maybe we will get there.
This.
The quarterly profits-driven consumerism along with 3-4 year model cycles has meant the demise of the cheap basic car that can last through one’s retirement. Japan already has a huge aging problem—and they have much more massive transport system in place. As America ages, it’s looking pretty scary for the lower 50%—especially those who live rural.
This is why I like the LiFePO4 chemistry(and LiTO as well, although that still has issues with gravimetric energy density not being very good which will hopefully be resolved as it is superior to LiFePO4 regarding longevity). It’s less prone to degradation than Li Ion, and these batteries will run poorly at the end of life for longer than most Li Ion will run at all.
With LiFePO4, it may end up the case that cars using them are still drivable 30 years later on the original pack, but with only half of the original range. They haven’t been in use long enough for us to know their shelf life, unlike most other Li Ion chemistries which are at about 10-15 years.
NiFe is a “forever” battery. The ones in Jay Leno’s 1909 Baker Electric still work! You have to keep the potassium-hydroxide electrolyte topped up though. And the gravimetric energy density is about 1/4 that of modern LiFePO4 batteries.
For batteries without a memory effect (so not NiMH), a 100%-0%-100% cycle is equivalent to a 50%-0%-50%-0%-50% cycle.
Because of this, many scientific papers testing the longevity of a battery specify the cumulative amp-hours put through the battery rather than the number of times it was charged and discharged.
It should also be noted that batteries can last longer if they aren’t charged above 80-90% as well. Keeping them above 20% state of charge and below 80-90% state of charge at all times for Li Ion yields the most cumulative AH delivered over their service life before they are spent.
This is also true; the bottom line is that shallow charge cycles don’t reduce the service life of an EV.
Lithium batteries are widely understood to last longer if not fully discharged and not charged above 80% on the regular. Going 100%-0% and back all the time is kind of a worst case scenario for lithium battery testing.
Ceramic plates, huh? I like it, but it feels fragile. Feels like it could be an issue in a vehicle that experiences all sorts of NVH concerns, something that won’t necessarily show up in a lab.
Still. Good for stationary uses? New powerwall?
These aren’t your grandfather’s ceramics. The heat shields used on the Space Shuttle were ceramic. If certain ceramics can hold up to the NVH of launch and re-entry, I’m sure they can withstand a pothole. Maybe not a Michigan pothole, but ya know.
(Edit: Come to think of it, depending on how old you are, it’s entirely possible that the shuttle’s heat shields are in fact your grandfather’s ceramics! Damn, I’m old.)
I’m betting on flow-battery tech. Mostly because the recharge on those is a flush. So you could use service station type services.
Cambridge Crude (the old name for flow batteries) has been in development seemingly forever. It’s cool in concept but I haven’t seen more than a lab prototype.
Here’s an article from cleantechnica.com from a few days ago on where we stand. Apparently there are test vehicles using them right now:
https://cleantechnica.com/2023/12/31/new-flow-battery-electric-car-usa-ira/
So, we just have to hope the batteries never get hit by something really heavy, like a piece of styrofoam
Too soon, man. Too soon. 🙂
I think in this case, the styrofoam would have to get through the undercarriage, then through the battery outer casing and whatever else is in between before it will ever come in contact with the ceramic material. Should only be a problem if Tesla starts using this tech.
ooof
The heat shield tiles on the shuttle were ceramic and the strength and durability improved drastically along the length of the program. They were also fragile enough, fairly near the end of the program, to be damaged by the pressure you could apply with a fingernail.
I’m not a material engineer so I’m not 100% versed in the latest ceramic design, but I am a mech engineer that works on heavy equipment vehicle design. NVH does weird shit through the life of a product
The heat shields used on the Space Shuttle were ceramic. If certain ceramics can hold up to the NVH of launch and re-entry…
Those have their limits too:
NVH launch foam strike on Columbia’s ceramic layer:
https://en.m.wikipedia.org/wiki/File:Space_Shuttle_Colombia_disaster_ET208_camera.gif
Catastrophic failure of that same layer in re-entry:
https://www.theblackvault.com/documentarchive/wp-content/uploads/2015/03/hi-852-columbia-debris-03916459.jpg
I didn’t forget about those. Never will. But those incidents were a result of something a tad more violent than NVH.
Ultimately NVH was the root of it all.
It was the reason the foam broke loose, but not the reason the tile failed.
The tile failed because it was hit by the foam. The foam failed because it was shaken loose by the NVH of the launch. Ego the NVH of the launch caused the tile to fail. The foam was just an intermediary. If the tile had been damaged by a bird, the launch tower, a meterorite or some other external object I’d agree with you but that failure was ultimately the result of stresses from launch NVH.
It’s also worth noting the foam was moving just as fast as the tile the moment it came off and who knows how much air resistance there was to slow the foam down at that altitude during the moment between detachment and impact. So even though the impact with a piece of foam was relatively slow the tile still failed. Not what I’d call robust.
I get what you’re saying. Yes, NVH was an indirect cause of the tile failure. However, the impact of the foam against the tile was the immediate failure mode. Had the foam not struck the tile, NVH by itself would not have harmed the ceramic. So, I still stand by my statement.
“So, I still stand by my statement.”
You do you but those tiles had a history of failures long before Columbia:
https://abcnews.go.com/US/story?id=90890&page=1
It was just a matter of time till such a failure happened in a critical atea.
I think it is worth pointing out that an engineering material being ceramic doesn’t automatically mean it is fragile. A lot of people hear or read ‘ceramic’ and immediately think ‘just like my dinner plates!’ – but that’s not really valid.
When I first started working for Mack Trucks back in 2001, they were working on resolving some cam durability issues. The solution they put into production for the last generation of Mack ASET engines was to use ceramic rollers in the roller lifters on the cam instead of steel. I asked the valvetrain engineer the same thing – “won’t they shatter?” He responded by pulling an odd looking intake valve for a big block Chevy out of his desk drawer. “This valve is for a nitro funny car engine made out of the same ceramic as our rollers, it cost about $1000 to prototype. Whoops!” and he threw the valve on the ground. It bounced.
Engineered ceramic materials can be almost absurdly strong. Yes, they are ‘brittle’ in the technical sense that they don’t elongate before they fracture, but their yield strength is so high they can put up with a lot of abuse anyway. They are sensitive to notching, but so are hard steels. The big thing is that they’re sensitive to QC – any inclusions in the material can cause hidden stress risers that can cause failure, so the quality control inspections need to be very good. Plus, compared to iron based materials they are expensive. But in the context of batteries, ceramic is probably some of the cheapest material in there…
Highly tolerant to excess heat as well, to the extent that steel alloys will fail first.
Please contribute an article about Mack Trucks so I can live vicariously through your job
Yeah, Gorilla Glass is essentially a ceramic.
Isn’t regular glass technically a ceramic as well?
FYI, tungsten carbide is frequently referred to as a ceramic. This is the stuff that drill bits and mining equipment are made from.
Tungsten has the highest melting point and highest boiling point of all known elements.
Time for a road trip to the island of stability.
https://en.m.wikipedia.org/wiki/Island_of_stability
(I’m hoping for Naquadah)
And bright when burned (in the presence of oxygen) too 🙂
This is not the first time solid state lithium batteries have worked in a lab. There are two things I will need to see resolved before getting excited about this:
1. Other experiments have found SSBs have impractically high internal resistance (which limits power) unless the batteries are heated. Though QS performed their testing at 25°C, they did not publish the C-rates achievable at that temperature.
2. Experiments with ceramic SSBs have found their practical lifespan isn’t limited by charge cycling, but by their vulnerability to cracking under vibration or thermal expansion. QS has not yet mentioned any testing on that front.
So as nice as it is to see Quantumscape is making progress, they’re not breaking new ground yet.
Power limits aren’t a major concern. If you can get enough power out of the pack to have a car do 0-60 mph in under 12 seconds, that’s “good enough” if the application is an inexpensive to operate, inexpensive to purchase, people mover. A minivan or entry level car wouldn’t really be penalized with this limitation.
To be clear, I don’t care about sports cars. A C-rate of 1 would give 100kW for a 100kWh battery, and I can work with that. The problem is, the internal resistance of solid state batteries can rise by a factor of 10 between 25°C and 60°C (see graphics 1, 2). This can limit usable discharge to <1C and/or compromise effective capacity.
This will have huge impacts on fast-charging capability, which is the primary selling point of solid state.
VW always does a really good job with testing..
I see what you did there, and I LOL’d.
I read it as “VH” and now “Hot for Teacher” will be in my head all day.
Well, as a practical matter, thermal energy is more efficiently transmitted from one body to another by direct contact via conduction, than simply radiation or convection. So touching is better than just basking in the glow.
This is of course only considering simple physics, and totally disregards the effects of legal constraints in our calculations.
You’ve got it bad! My homework was never quite like this.
Bad.
Hey, teacher!
I’ve got my pencil…
(damnit: it’s 4am & I’m stuck with this Allll day)
“…Class Dismissed!” 😉
Always teach to the test.
This could be a game changer or …. Batterygate. It is VW.
My thoughts exactly. I was thinking E-gate.
It seems important to know whether the charging tests were in fact full cycles from 0-100% charge, as implied here. Everything I’ve read says this is the hardest on the battery. Of course, most people won’t deep cycle very often in normal use, but that also means most people wouldn’t get 500,000 km out of 1000 cycles either.
I’ve had a couple rental Tesla’s before and I think this might be one of the driving factors towards EV rental adoption. It turns out if you don’t provide renters with a NACS-CCS adapter or cable, people are only left to fast charge their cars ALL the time which isnt very great for the battery.
In the case of Tesla’s packs, they are engineered to withstand fast charging without any extra degradation observed.
https://electrek.co/2023/08/29/tesla-battery-longevity-not-affected-frequent-supercharging-study/
As much as I love EVs and have built a career in the industry, the fact the multiple Tesla’s I’ve rented have gotten only 60-70% range estimates says otherwise. Perhaps it’s just because Tesla overestimates their range too much which they are known to do. I’ve been able to get within 90% of what Polestar and my employer that’s not Polestar states for their range.
Tesla does over-estimate their range. Modern EVs are built to maximize EPA-tested range, and not actual real-world range. There’s all kinds of software tricks they can use to inflate their results.
Aerodynamic drag reduction also makes a much bigger difference on long distance trips at highway speeds than the EPA highway cycle would make you believe. This is why the Porsche Taycan tends to do slightly better in the real world than its EPA range, while the Tesla Model 3 tends to do slightly worse.
A lot of the degradation you are seeing may be from packs that were discharged to 100%, where a small number of cells suffered premature damage as a result, dragging the rest of the pack down with them. A series string’s deliverable AH capacity is only as good as its weakest cell.
BTW, how did you get your career in this industry? I want in very much. I’m an electrical engineer working a much more boring job than that.
My custom built EVs have been hobbyist tier builds, but I have made a 3-wheeled micro EV that only needs about 8-10 Wh/mile to cruise 30-35 mph, and in stop and go traffic around a city environment, could get 150-200 miles range on only 1.5 kWh. That pack could make 3kW peak, was put together for $200, and had more than 20,000 miles placed on it before swapping it out for something else, and still works, getting a 2nd life in a mountainbike conversion running 750W.
In the 3-wheeler, the battery has since been upgraded to a more powerful 1.7 kWh pack that can do 50 kW peak, but is currently only using 10kW of that.
Getting a career in this industry was really just being passionate about cars and what the specific company I’m at does. However the one downside is that any of the EV startups that you’ll want to join will be in a very expensive location. The big OEMs are a complicated hiring mess with interviews that make no sense.
I’ve been passionate about cars my whole life and passionate about EV technology since I was a teenager in the early 2000s, and tried to get my foot in the door when I graduated university in 2007, to no avail. I had student loans to pay off and couldn’t continue chasing my dream job, even though it was the reason I went into electrical engineering to begin with.
I was 16 when I started drawing up the schematics for my Triumph GT6 EV conversion, before I had a donor chassis in my possession.
Considering how EV startups are in a hiring frenzy, now would be the best time to start applying.
Keep applying for your dream job. It took me six years after I graduated to get in to an OEM with a job role I hated, and another two years until I could move in to powertrain design, which is/was my dream job.
Now, of course, designing ICE is a dead career, but I had a fun couple of decades, with quite a bit of EV, REEV and hybrid work too.
It’d be a shame for your enthusiasm and skills to go to waste.
EV Consulting (i.e. contract work) May be a good way to get professional experience. This is a super common way people start out in IT/Tech..
When I 1st graduated I did general admin. contracting with GMAC for a year before I was able to find an FTE role in IT, which only lasted 1 year bf I moved and went back into contract work for another 18 months b/f landing a CTH (i.e. contract to hire) opportunity with a fortune 50 company.
Rental use case is interesting. It’s always a nuisance to return a car with full tank (if you are cheap like me). Now I’ll have to head to the airport even earlier to charge up a return.
Returning a car with a full charge isn’t necessarily the worst problem. Certain hertz locations offer EVs, but the location itself has no charger. Imagine getting a Model 3 from Hertz with 50% charge when you were planning on a 120 mile trek. Now that’s the worst thing I’ve ever encountered. Bonus points if the car has no charging adapters so the hotel you wanted to stay at that has CCS ports can’t charge your car.
Or you charge it the night before you return it.
Not that big a deal.