Mercedes‑Benz starts large‑scale production of electric axial flux motor
media.mercedes-benz.com382 points by raffael_de 9 hours ago
382 points by raffael_de 9 hours ago
Mercedes acquired Yasa (UK) couple of years ago and now getting up to the speed in the production.
Here is a nice video that explains axial flux motors with a factory visit
https://youtu.be/B2Hl4c1iZK0?si=VfDYARyuaPVj1nKm
They are so, so, small.
I was curious how this thing works and asked Claude to visualize it -- mostly to see how good Fable is and I have to say, what it made was good enough for me to get a gist of it. Posted it here
Every plausibly cool electric car innovation leads me to the same thought: “5-10 years from now, the restomod potential will be wild once these come down in cost.” For this, I am imagining retrofitting a Pontiac Fiero to reduce as much weight as possible and see if extended flight becomes possible.
Here’s a build series of an ex-Apple/NASCAR/Tesla engineer turned YouTuber swapping Tesla Model 3 drivetrain to a 50s Jag.
https://youtube.com/playlist?list=PLoTU9_iCGa6i_C38pwQyg0pBG...
I'm going to replace the differential and the automatic transmission in my truck with a 4-cylinder engine and an electric transmission.
Number 1 problem is battery weight though. Not electric motors.
I have a 84 w123 300D, and would love to add some more power to it. Lightweight hub motors would be great, but any decent size battery would be at least 200lbs+, which is hard to do on a old chasy.
its less hard than you'd think unless you're really going for long range.
for my sailboat I am getting rid of a 300lbs diesel and a 30gallon fuel tank with a 45lbs PMAC.
That means I have opened up about 465lbs for batteries.
Now, with a sailboat you're never truly out of range -- but the point stands : these things are so much lighter than ICEs on average that there is a lot of opportunity even with battery weight as it is (and it's getting better daily).
Something to keep in mind with hub motors is that they’re unsprung weight, vs the battery pack is pretty much always sprung. While that’s not a huge differentiator for efficiency, it sure cuts down on the abuse the wheels and hub motors will experience
i know series hybrids aren't as efficient as parallel hybrids (thanks technology connections!), but i wonder if they'd be a good candidate for fun restomods.
drop in a tiny, powerful electric motor and a small battery (crammed in whatever location is best for weight distribution), and then wire up a little genny powered off your existing fuel tank that can jump in as a range extender
Yeah, my comment was hand-waving away a bit of the reality of it, but swap the Fiero engine for a battery and some of these and it's got to be close to achieving full lift.
I think the cited weight loss comes from energy efficiency gains leading to less battery capacity needed.
Electric engines are already very efficient (particularly compared to internal combustion). If you go from 90% to 95% efficiency, you don't save much in terms of battery.
ETA: Internal combustion engines half a century ago had an efficiency of 20%, now they're at 40%. That cuts the fuel you need to carry in half. Electric engines are near 100%, and as I said, going from 90% to 95% efficiency cuts required battery by a bit more than 5%, so peanuts.
In the video the yasa guy said most of the weight loss is from getting rid of the yoke.
Can you elaborate a little on what you asked Claude to do here? This is a pretty impressive one-shot.
This viz is superficially neat, but hard to get info out of. It seems like a demo in a movie.
What did you like most about it?
Yup, the visualization didn't help me understand the concept any more than plain text. Superficial in the way that you would expect from a system that has no real world reference for what it is creating.
To get something better I expect more than a one-shot is needed, and the knowledge to guide it in the right way.
Thanks for sharing. I wish it was a bit more interactive especially when there are parameters, e.g. "Widen the disc and torque rises with diameter cubed" I wish there was a slider to see that effect and thus maybe why there might be a sweet spot.
Also I have "The Way Things Work" on my desk right now and can't help but wonder, could you adapt some of the pages of the book this way? It seems like exactly the kind of content that would benefit from such 3D (interactive) visual explainers.
Code is here https://github.com/mohsen1/axial-flux-motor-explainer
Feel free to steal! This was one shot with Claude Code. You can take it and adopt it to your need
Oof... well thanks for sharing but that's basically unusable for me. It neatly all packed in a 2MB file containing all assets, threejs, etc.
I assumed it's based on a three.js template due to the `Rendered live with three.js · Drag anywhere to orbit the model` kind of showcase but unfortunately that's not linked. I also imagine the 3D models are more that primitives (at least the arrows showcasing the flow) but I don't know where they came from, if that are also from a template or repository or if they are generated from a tube mesh.
So... I'm genuinely grateful that you took the time to share but I don't think I can do something with this except restarting from scratch, especially if it's one-shot.
I'd suggest, if you don't mind the extra effort, that you add a ReadMe.md in the repository to clarify how you did this, at least model name, version and prompt.
I mentioned elsewhere too. This was a one-shot thing that made me wow so I thought I share. You're kind with your comments but others are just hating it, even so I said 1. I don't know this motor technology and 2. It was a one shot experiment
If I had time and making a polished web page was my goal I could probably do better but this was not the point!
I made it live and editable here: https://hallway.com/workspaces/f7cfb27c-0a0b-4ca3-9b28-cc7eb...
I asked mythos to make a "The Way Things Work"-inspired version.
Published: https://banagale.com/the-way-the-motor-works/
Source: https://github.com/banagale/the-way-the-motor-works
It lacks cave people but has the woolys.
Thanks but I'm aware of it, linked to an alternative just yesterday (but might replace by the InternetArchive one instead). A Web version would be so neat as we'd be able to link to pages, even states of the interactive explanation, rather than the whole thing but it's already great to have that basis.
The issue with this is, without an expert, how do I know I am getting an accurate representation?
Hundreds of examples of axial flux motors exist online. If you look at the visualization it shows the iron cores in a perpendicular orientation with the hub. This is correct, but loses so much of what makes these specific motors interesting. The angled nature of the grey cores and copper wrapping smoothes the transition between each magnetic field.
Basically it is a pretty version of a dumbed down partially incorrect answer. With a knowledgeable user it would be very good, but he has no idea he is wrong. I’m not sure what Dunning Kreguer with graphics should be called.
The question is for you to answer, first. Gotta do that work. (My answer will differ from yours.)
Then, predictably, finding the collection of supporting details + vetting the content in question.
This is an issue we, technology-folk, ought to help guide our non-tech-co-folk through engaging with, BTW. Our responsibility is rising with tech becoming more deeply entrenched / required for society's operations.
You don't. You didn't know before either. The difference is trust. How do you trust it as much as you do the hypothetical humans making such representations? That's up to you.
I think humans develop expertise and brand names and get called out when they make mistakes and if they are too wrong, their reputation is damaged.
This doesn’t seem to apply to AI for some reason. It keeps generating incorrect results after incorrect results, yet people continue to trust its output.
I don’t know what to make of this.
"Trust" is an abused term, nowadays.
Human trust differs from mathematical trust. And branding / marketing abuses the ambiguity.
There is no shame in a "likely to hallucinate" model that can be instantiated 1,000 times across 1,000 different machines spread throughout our planet. So, human trust is broken by machine trust.
I've starting going back to books, either at the library or e-books. Librarians are very good at telling you if nonfiction is biased, outdated, or incorrect.
wait until AI starts publishing printed books :)
https://www.amazon.com/stores/Dave-Gary/author/B0BY6Z6HP8/al...
Honestly, I don't think this actually provided much above a paragraph of text.
The visuals didn't show much, and I learnt a lot more from one of the YouTube videos (https://www.youtube.com/watch?v=dCO633KE7RA) posted below.
It's neat that a whole interactive deck can be produced without effort. But it's just not very interesting.
Yeah, I'm at once awed that something like that can be auto-generated (I presume?) and disappointed that it doesn't usefully or practically improve my understanding, beyond written synopses and human videos, at all.
Stuff like this reminds me that we still need a human in the loop to edit, to improve, to advance.
Auto-from-scratch just doesn't really achieve anything of actual value.
what was the prompt for this, did you use a CAD/threejs skill or grab a model from somewhere?
I am not an expert, but I do know some physics and I know how to read, and I’m pretty sure this is full of BS. Also it’s a really crappy visualization.
That was a good video, and I also liked the Munro video that does a nice job of explaining how these work: https://www.youtube.com/watch?v=m507ryWhc6c
I wonder how developing electric motors compares to combustion engines. My hunch says that it’s the main reason the Chinese high-tech electronics industry was able to develop and iterate leading electric vehicles so fast. (Edit: My more clarified point is regarding the machinery required + place to accommodate them to work on electric motors vs. ICE metal parts and all the intermediary parts transfering power in the drivetrain. The shop in the video is smaller than many would imagine.)
When these hopefully go to the next generation Formula E cars, we’ll see some crazy improvements in cornering. The newest generation already has active 4WD. I imagine this can bring even better torque adjustment improvements.
The Chinese EV industry is actually lead by development of batteries, especially CATL. Along with the pack engineering, which is good old Mech.E stuff about heat transfer and physical strength.
Secondarily power electronics; at that scale, you can't just pick a bigger transistor and call it a day.
By comparison the motors seem to be a mostly solved problem, although I'm sure there's still some scope for power-to-weight engineering there, it's not as critical as the battery pack.
I thought that for a long time the german supply chain had an advantage in terms of the precision engineering to create drive chains for ICE - but EV's don't have the same number of moving parts and hence... end of advantage?
And is development of batteries (and better magnetics) not just chemical engineering and material science?
Motors might be a 'solved problem' - there might not be much innovation, Maxwell's laws aren't changing any time soon, but there will surely be a lot of incremental improvement - an early 1900s ICE is considerably worse than a 2000s ICE.
> n early 1900s ICE is considerably worse than a 2000s ICE.
But how much worse is a early 1900s electric motor from a modern one? I can't find data, but I suspect the first electric motor from the 1830s is more efficient than a modern ICE (even if we assume the ICE is built for efficiency, screw emissions). There is some room for improvement, but there isn't much difference between our best motors and perfection (a carnot cycle by contrast is as best much worse than perfection)
Early electric motors were awful, because there was no good way to control their speed.
For example, DC motors used in some late-1900s trains still had a giant variable resistor in series with their motor, burning away a huge chunk of the power as heat to force the motor to run at a lower speed during acceleration. AC motors weren't much better.
Electric motors only became truly efficient when variable-frequency drive became viable, which was in the 1980s due to semiconductor innovation.
Helped along by the somewhat Wild West attitude towards worker safety and industrial regulation - high energy density batteries are hard to get right, and extremely dangerous if done wrong. During manufacturing in particular.
And only get cheap at scale.
> The Chinese EV industry is actually lead by development of batteries
This is the core point, but it applies for the whole of the industry. Motors just don't matter. An electric motor is an almost vanishing component of the weight and complexity of an electric vehicle. Cut the mass of the thing *in half* and you're looking at 100kg savings, tops. You could do that with a Model Y by just changing the roof material to something boring and not glass. You could almost do it by shrinking the oversized-as-is-the-fashion wheels.
So... it's great that Mercedez-Benz is producing these, I guess. But it won't make their cars anything more than incrementally better. Which is why we're seeing them crow about it in a press release and not a spec sheet.
Standing on the shoulders of giants, mainly.
All the industrial processes and machine tool development that happened in the ICE car industry over the last century (and the electronic hardware manufacturing, more recently) was available day one.
>I wonder how developing electric motors compares to combustion engines. My hunch says that it’s the main reason the Chinese high-tech electronics industry was able to develop and iterate leading electric vehicles so fast.
The talent had very little impact to be honest. The primary factor was a government looking 50 years down the road seeing that:
1. ICE engines have little to no long-term future in transportation.
2. global warming is a thing whether the right wing in the US likes it or not.
3. They were never going to overtake the West in ICE engines and had to attack from a different angle.
The US' lack of breakthroughs in EVs has little to do with technology or expertise and everything to do with an administration that is openly hostile towards EVs and renewable energy in general. For the rest of the planet, EVs becoming the primary form of transportation is just an obvious and logical conclusion, even if it takes us another 25-50 years to get there.
China saw it and decided to heavily incentivize and subsidize the rapid expansion of EVs both to fix the air quality issues in China and corner the market.
> The US' lack of breakthroughs in EVs has little to do with technology or expertise and everything to do with an administration that is openly hostile towards EVs and renewable energy in general.
It has nothing to do with the current administration either. For one thing, China's dominance predates it. For another, the EU and Japan have failed equally hard at capturing any meaningful EV marketshare.
1. There is still no good answer for air transport, trans-oceanic shipping, long-haul trucking, and long-distance rail. ICE will be used there for a good while longer.
The current admin is actively hostile to EVs, but I think the real problem was the chicken and egg issue of charging stations: they wouldn't be built because there wasn't enough demand for them and EVs would be limited in sales because they wouldn't have chargers to use on the road.
This is where Tesla made a huge difference with Supercharger stations. I am no fan of Elon, but that work was fundamental in making EVs viable in America.
The new season of Formula One feels (unfortunately) like Formula E!
In Formula E the drivers control engine behavior and regen. It is much better than F1 right now.
It would be awesome if they would implement a crude rule: no computers. You can use a computer to design the car--CAD/CAM/CAE are all fine--but no stored program computers are allowed in the race car. I think that would improve F1 tremendously.
Very funny idea. That basically means a carbureted gas engine, or a direct injection diesel with a mechanical governor and mechanically timed injection pumps - can't run a direct injection gas engine without a digital engine control unit, because the injection timings are much to precise to do mechanically.
So, basically '60s Formula 1. Might be fun to watch. We'd certainly see some crazy engine designs and a lot of re-fueling pit stops...
> can't run a direct injection gas engine without a digital engine control unit, because the injection timings are much to precise to do mechanically.
This is not accurate, the first production direct injection gasoline automotive engine was in the 1954 Mercedes-Benz 300SL. It's true, you probably won't be running piezoelectric injectors without computer controls, but there's nothing preventing direct injection.
But that would make it interesting. How many of the advances we've made in the past 75yrs could be accomplished some other way if you take the computer away? You don't need a computer to accomplish nanosecond timing. Maybe there's a clever analog way to run piezoelectric injectors.
I'm not saying there isn't room for innovation but... Electric motors have been around for a century now already in many applications.
It's not like the Dawn of the steam engine
According to wikipedia[1] the first industrial steam engine (1712) was invented almost 100 years before the invention of the steam locomotive (1804), arguably its greatest evolutionary feat.
[1] https://en.wikipedia.org/wiki/History_of_the_steam_engine
The timeline of the electric motor isn't much behind. https://en.wikipedia.org/wiki/Timeline_of_the_electric_motor.
> develop and iterate leading electric vehicles so fast.
How do you know this for a fact? Chinese press releases? You've driven one? Some auto blogger drove one?
After world war 2 Gorbachev or whoever visited the United States and during that trio visited a supermarket. He thought it was a facade, possibly, put on just for him, there's no way Americans are this prosperous (or whatever, this good at agriculture, farm equipment, etc)
Also do the race cars have 4 wheel drive, or all-wheel drive? I'm wagering all-wheel with "torque vectoring" and "Yaw control", like a Mitsubishi Lancer Evolution X.
I am somewhat confused at the intensity of pushback for the statement “leading electric vehicles.”
Chinese EVs are leading and that doesn’t necessarily mean being the best, most advanced vehicles. They are leading in value/pricing, and in many regions they are leading in sales.
BYD sells almost double the EV volume of Tesla globally as of December 2025. They are objectively leading in that respect.
I think the parent comment of yours made a good point (or at least adjacent to a good point) about China’s ability to enter the market: they can’t compete with 100 years of internal combustion engine development along with the vast parts supplier network of the West, but they can compete on battery chemistry, battery supply, motors, and the more vertically integrated EV space where automakers don’t need to depend on a huge network of parts suppliers like they did in the past.
I also think that a lot of pushback to the innovation that China is delivering is criticism that is stuck in the past. If you buy a Xiaomi car, it integrates perfectly with all your Xiaomi consumer devices. You can control your rice cooker or robot vacuum from your car’s integrated infotainment system. This type of approach was exactly what Apple was going to deliver before they abandoned their automotive project.
Or, you can buy a Mercedes and you’ll get a car with more precise handling and perfectly tuned driving characteristics. The infotainment system looks like Windows Vista.
Which side of the aisle do you think most consumers care about? I think most people buy into Xiaomi’s approach.
Semiofftopic but somehow I took offense at the Vista comparison. Aero Glass was peak UI design to me, and I'd certainly prefer it to modern paradigms like flat controls, or to stretch it even further, Corporate Memphis etc.
Curse you, Apple and Jony Ive. You only needed to tone skeuomorphism down not kill it.
I’m genuinely delighted that this reaction to that little phrase came up! It was definitely something of a half-joke on my part: the Mercedes infotainment system is very well-regarded, but it does not look “modern” compared to something like a Tesla, Rivian, or Xiaomi.
The hyperscreen from a physical hardware perspective looks strangely dated to me as well, depending on the specific car model.
I wouldnt be so harsh even with chinese combustion engines, its at this point a meme that is just copy pasted because everybody says so, but without actual experience. People dont understand how China is 3x bigger than Europe and 4x bigger than US, the scale of that market is absurd and competition numerous and fierce.
I've had MG suv rented recently with just gasoline engine and it was fine. This comes from long term bmw driver, they are not on the exactly same level, but light years ahead from similarly prices ie french vehicles. Handling was fine too, probably the biggest shock for me, this is where french, italian etc are losing me (bmw effect). And they cost 1/3 of bmw.
True, and on a similar wavelength, nobody seems to care that Kia/Hyundai engines are super mid.
Heck, nobody seems to care that Toyota engines/transmissions sound like a vacuum cleaner and have pretty mediocre NVH on models like the Corolla, but they buy those products for reliability and efficiency.
I think with xiaomi yu7 and Tesla killing the model S, the chinese are leading in everything when it comes to EVs.
Listening to the heads of the American and European car companies say the same and driving in them in china. I know that is different than personally disassembling one and reviewing it, but I am not sure the incentive for the other companies to say they have inferior products, unless it was a play for subsidies or deregulation of some form.
Personally I feel that the rest of the world continues to dramatically under estimate China’s progress and technological advancement at our own peril. Is there fluff and are their lots of untrue claims, of course, but that is certainly not something they have a monopoly on.
It's because the West still views Chinese people as dumb laborers: just a bunch of cheap bodies who can do nothing more than screwing together our brilliant inventions.
China creates something of equal quality as a Western company? It must've been IP theft! China competes on price? It must be state subsidies! China creates something innovative? Don't use it - it'll send your data back to the CCP! Or just pretend it doesn't exist.
In reality Chinese people aren't idiots. We've spent a couple of decades giving away all of our manufacturing knowledge for a few cents of shareholder value, so it is not exactly surprising that they now possess that knowledge - and are able to build upon it. China is dealing with huge demographic changes, so obviously they've been pushing for automation, so it shouldn't be a surprise that those factories are now rapidly automating. Which we could've done in the West, but outsourcing it to cheap Chinese labor was cheaper in the short term.
For every genius in the West there are ten geniuses in China, and with their top-down economic policy they are able to apply it where it truly matters.
We created our own worst enemy, and are now crying foul. If we don't get rid of our outdated racist biases soon and start treating China like the successful superpower that it is, we're going to get completely steamrolled in the next few decades.
Aren't you getting your analogy backwards? American supermarkets have the same role in the story as Chinese cars.
Great video!
So it looks like axial flux, the OG was introduced in 1820 something and it wasn't easy to manufacture. So radio flux came after that and has been around ever since. So axial flux is making its come back this year!
The video is very interesting too about decompounding returns when the motor is less with the other things need to weigh less too.
Especially the bit about potentially not needing brakes in the near future because the regen is so capable. Which would lead to less weight and less parts even again!
A few years ago I built a few small ones in my home lab. They are extremely efficient. With the right setup, have insane torque, and don’t require a lot of energy to do it. The best part for me was that they are completely brushless by design and are easily to keep clean.
Came here for this, thank you for providing a link
Edit.... Video doesn't seem to explain very well either
It would have been awesome if that article had, at any point, explained what an electric axial flux motor was, and why anyone might want one.
Click "More" and scroll down:
"In contrast to conventional radial flux motors, the electromagnetic flux in an axial flux motor runs parallel to the axis of rotation. The key components are arranged in a disc‑shaped layout: two rotors sandwich the stator from the left and right. This design enables an especially compact motor architecture, high power and torque density, and new freedoms in drivetrain packaging. In the new Mercedes‑AMG GT 4‑Door Coupe, the motor at the front axle is just under nine centimetres wide; the two motors at the rear axle each measure around eight centimetres in width. The three axial flux motors are integrated per axle into so‑called High Performance Electric Drive Units (HP.EDU), where they are combined with a compact input planetary gearbox in a single housing."
Really the kind of thing that should be earlier in an article about… that very thing the reader is wondering about, but maybe we arent the target audience?
This is the same design that enables the PCB Stator Motors, right?
Yes. If you have a laser printer, that windup sound you hear at the start of a job is the polygon mirror motor spinning up thousands of RPMs - those are PCB stator motors. As were VCR head motors.
"Advantages : A motor can be built upon any flat structure, such as a PCB, by adding coils and a bearing." https://en.wikipedia.org/wiki/Axial_flux_motor with image of "A miniature DC brushless axial motor used in a Digital Data Storage drive, showing the integration with PCB construction techniques."
For some reason that reminds me of https://www.youtube.com/watch?v=aW2LvQUcwqc
> This design enables an especially compact motor architecture, high power and torque density, and new freedoms in drivetrain packaging.
Hand waving.
No, it means the motor is smaller and it can be put into the wheel
It doesn't make that a good idea. Armature losses are proportional to torque squared - doesn't matter if it is radial or axial design. That's why all the EVs today have gear boxes with ratios like 13:1. Get rid of that gearbox and the steady-state losses go up with the square of that ratio. Then there are the issues of sprung mass, and where to put the mechanical brakes.
YASA claims their integrated brake/wheel motor is lighter than comparable (supercar) disc brake systems.
>gear boxes with ratios like 13:1.
you add planetary gears
>sprung mass
you can integrate all into one hub (breaks, bearings, gears etc) and it weights pretty much the same.
what you gain is more space for a bigger battery, torque vectoring, no loss on diff and CVs
aren't there other issues with having the motor in the wheels? Unsprung mass, plus the wheels can get pretty banged around?
A very good YouTube video from Munroe Live (an engineering firm specializing in "design for manufacturing") explaining it: https://youtu.be/dCO633KE7RA "Axial Flux Motors Explained"
Edit: a video from them on this particular YASA tech being discussed : https://youtu.be/m507ryWhc6c
Visited Astrall Dynamics, a Chinese startup that builds quadrupeds with axial flux motors here in Shenzhen. Super cool to see the robots in actions, carrying 60kg of weight up over 20 flights of stairs quite rapidly. The high torque at the compact form factor was super impressive. As far as I understood they are more complex to manufacture, especially at scale.
It's a bit buried, but it does:
> In contrast to conventional radial flux motors, the electromagnetic flux in an axial flux motor runs parallel to the axis of rotation. The key components are arranged in a disc‑shaped layout: two rotors sandwich the stator from the left and right. This design enables an especially compact motor architecture, high power and torque density, and new freedoms in drivetrain packaging. In the new Mercedes‑AMG GT 4‑Door Coupe, the motor at the front axle is just under nine centimetres wide; the two motors at the rear axle each measure around eight centimetres in width. The three axial flux motors are integrated per axle into so‑called High Performance Electric Drive Units (HP.EDU), where they are combined with a compact input planetary gearbox in a single housing.
> The three axial flux motors are integrated per axle
I wonder why they need tree motors per axle.
It's poorly worded. There aren't three motors per axle, there are three motors total: one on the front axle and two on the rear axle.
The translation's a little woolly.
For the AMG GT4 there will be 3 motors: two at the rear, and one at the front.
My interpretation (and my German's pretty lousy) is that each motor is combined with a gear system in a single package, and they're calling the overall package (motor plus gears) a High Performance Electric Drive Unit (HP.EDU).
The two rear motors will probably be independent, so no need for a mechanical rear diff (it'll be electronically controlled).
There's no mention of a front diff, so it's unknown whether that's built into the front HP.EDU or is a separate mechanical diff).
In terms of traction control, does this translate to something between "4WD" and "AWD"? Or is it orthogonal?
Kind of orthogonal. Traditional AWD and part-time 4WD systems are solutions to get power from a single motor to both the front and rear of a vehicle. AWD has a center differential to account for differences in front and rear driveshaft speeds when driving on high-traction surfaces. 4WD just locks the front and rear driveshaft rotation together, which is a simple and robust solution that only works on loose surfaces.
With separate front and rear electric motors, there's no center differential to worry about, and a sufficiently sophisticated motor control system can make it behave well on and off road.
This is probably the most succinct explanation I've ever read of the differences and the advantages of one over the other. I've been trying to understand this from different sources for years now.
I'm not sure that the traditional notion of traction control applies, given that there are three independent suppliers of power, so you don't necessarily need the mechanics of diffs and computer-controlled brakes to provide maximum traction.
What would it mean to "turn off" traction control in a car with independent motors per wheel? (OK this is a 3-motor/4-wheel scenario, but hypothetically…)
With software control and independent motors, we're likely to see increases in low-traction capability (for the right price-point and probably aimed at particular buyers)
To build on what others have said. Multiple motors per axle allow you to get rid of the diff, and you get torque vectoring basically for free.
Then there's braking. More driven wheels means more braking energy that can be recouped via regen. In traditionally rwd cars you lose out here because braking energy tends to be directed forward.
Also there's packaging. One large motor might impinge on the cabin.
Also you get benefits wrt mass production.
A smaller motor is easier to handle. Potentially could avoid the need for high voltage cables. Which eases repair.
I got the impression that there were three motors altogether and they were integrated with the axles.
“What“ might be a long answer, but why anyone might want one is to have increased torque density for the given volume and diameter. So they are thin motors where the generated flux is parallel to the shaft. And they are like the standard PMSMs where you apply the same driving algorithm from the inverter side to use them.
Here's a great Instructable on building one yourself, much better explanations in there.
https://www.instructables.com/Designing-and-Building-an-Axia...
It's basically the V8 of electric motors. Different topology results in better power to weight ratio. From the outside they look pancake shaped.
I want a V12 or V16, thank you very much.
V5?
https://en.wikipedia.org/wiki/VR5_engine
We owned an vw inline 5 Passat (quantum in North America). Good engine and synchro awd.
I'd like a 600 HP 1.5l supercharged V16 - doesn't even need to be in a car, mainly just to listen to!
If the displacement isn’t measured in cubic meters, can you even call it an engine?
Bonus points if you have to heat that crap you call fuel before you inject it into the massive cylinder.
Ok, me too now. But you can’t have that, so maybe you could settle for a high-reving V8 in a tunnel?
Then all you need is a good recording and decent headphones
A good recording and a sound system which can move the exact amount of air that the engine has moved, to be precise.
Since they're relatively compact they will probably start stacking them. Like pancakes.
Stick two of them together on the same axle then.
Why do you need an axle?
Put the engine and its transmission to the wheel mounted next to each wheel.
No need for differentials etc, if they can work out a steering mechanism for each, then you've got 4WD with 4W steering.
In the video there's talk of how you can use them as regenerative braking as well, so have that as part of the wheel structure.
No axles, no differentials, independent suspension, electronically controlled power to each wheel, regenerative braking.
Gonna be a fun decade or more of innovation coming.
Wouldn't putting them in the wheel increase unsprung mass, which would degrade the feel of the car?
I think he was talking about small engines the size/weight of existing disk brake assemblies. So either no change or weight reduction.
Most motors have N-S axis of magnets aligned tangential to the axis of rotation. Axial flux motors have N-S poles parallel to rotation. This allows motors to be thinner and wider as well as anyhow more lighter and sometimes easier made. Whether they make sense depends, it seems.
This sounds straight out of an 89’s sci-fi flick. What time we get to live in!
Consider the thousand or so comments at https://hn.algolia.com/?q=axial for more details. While it’s no substitute for a well-written comprehensive article, it certainly is a smorgasbord of answers.
The automotive part is interesting:
https://en.wikipedia.org/wiki/Axial_flux_motor#Automotive
> Mercedes-Benz subsidiary YASA (Yokeless and Segmented Armature) makes AFMs that have powered various concept (Jaguar C-X75), prototype, and racing vehicles. It was also used in the Koenigsegg Regera, the Ferrari SF90 Stradale and 296GTB, Lamborghini Revuelto, McLaren Artura and the Lola-Drayson.[9] The company is investigating the potential for placing motors inside wheels, given that AFM's low mass does not excessively increase a vehicle's unsprung mass.[10]
> In July 2025, YASA announced a prototype 550 kW (738 hp) 13.1 kg (29 lb) motor, equating to power density of 42 kW/kg, which the company claimed to be the highest ever achieved.[11] By contrast, the state of the art EV motor from Lucid Motors offers a 500 kW, 31.4-kg motor, or 16 kW/kg.[12]
> The first application of these motors will be in the High Performance Mercedes‑AMG GT 4-Touring Coupe.[14]
Thanks for posting this. Axial flux motors aren't some new sci-fi invention. We've had them in gadgets for a long time like in the floppy drive example. This is just one of the first industrial scale implementations of high-torque applications.
> Axial flux motors aren't some new sci-fi invention
Indeed not. The first ever electric motor was an axial flux motor built by Michael Faraday in 1821. It's definitely not a new idea.
Here's a good video on it from my watch history: https://www.youtube.com/watch?v=dCO633KE7RA
This one gives a shorter more high level overview https://www.youtube.com/watch?v=B0CNZPenCb8
I would be careful about that video, it seems relatively "explaining this new amazing innovation that has no/negligible downsides (please invest in us)" rather than "explaining the practical pros & cons of this technology".
The AI voice is annoying, the content is as personal a a vanilla yogurt but the animation is clear.
Great video. I didn't know I was so interested in engine design before I watched it.
As far as I understand it's so small and lightweight you can put one on each wheel and remove brakes and still save weight (something something unsprung weight bad).
Great overview on overcoming traditional motor flux saturation & density issues https://youtu.be/m507ryWhc6c?t=397
Very cool. Good to see more axial flux motors in the wild - will be interesting to see if they become the new standard in future. With smaller material costs the cost to manufacture at scale could actually become lower than radial
I expect radial will still dominate for at least another decade or so outside of premium performance focused cars. Radial has been battle-tested and proven. Axial still has a few more years to prove it's reliability in the field. Higher loads and stresses, tighter tolerances could make the axial motors less reliable overall especially at mass market trims. Mercedes is probably over-engineering for reliability and performance on the premium car
Radial is also "good enough" for most applications. The efficiency, form factor and weight improvements of axial is nice, but they aren't the limiting factor. Radial is already highly efficient, reasonably light and small. The real level for weight is the battery
I remember when YASA announced it and when MB bought them. Amazing technology and advancement in electric motor design. Good to see they somehow try to commercialize it.
My highlights:
> In the Coupé, the engine on the front axis is 9 cm (3.5 inch) wide, the two engines on the rear axis are 8 cm wide each (<3.2 inch).
> The fully electric "Performance" model accelerates from 0 to 100 km/h in 2.1 seconds.
ETA: Images of the engine:
https://media.mercedes-benz.com/article/bebac2af-acdc-465a-9...
https://media.mercedes-benz.com/article/bebac2af-acdc-465a-9...
An interesting part here is probably manufacturing and not the motor itself : going from a prototype to something you can mass produce reliably is often the hard part
This video explained to me what an axial flux motor is and how it's different to radial flux.
Amazing what materials science achieving to get this sort of power as well as the engineering and manufacturing.
Glad YASA's achievements are being realised but the UK really needs to get it act together so we can fully realise the next tech breakthough.
For family cars we need 4x 30-50 hp units. If the motor can weigh around 7 kg it can be placed directly on wheel. Adding durable brake discs (rarely used) and 2 inverters front ad back and we have the EV platform of the next 100 years
do we need disk brakes?
Yes, you must be able to stop independently in the case of some kind of total power failure in the drivetrain.
As opposed to relying solely on engine braking (or the EV equivalent thereof)?
I'd personally prefer a belt-and-suspenders approach.
Tangential, how much regen can this system support?
For example, can a car with 200kW propulsion have a 400kW regen (Tesla has upto 65) and are cost effective like friction brakes?
All motors are generators. It's only a matter of how you are creating the magnetic field with the stator windings.
In order to generate a higher regen, you'd have to somehow get more energy in the motor first... and since its only rated for 200kW, good ol' physics limits you, IF thats all the energy you put into the system.
If you roll it down a hill, or do something exotic like inverting the magnetic fields .... you can exceed the motor rating. But thats usually not recommended because the motor driver itself isnt rated to handle that power.
You're also ultimately limited at the point where the tires lose grip and start sliding. Which can vary a lot based on road surface and conditions.
In general the rating of a motor is about heat dissipation, which in turn is a function of efficiency. What this means is you can exceed the rating by "some amount" for "some amount of time". Many motors are rated for not what they can deliver, but what they can deliver continuously without overheating, but you can get a lot more power out of them for a short time.
Their founder/CTO discusses that here and their ability to match the braking power density of carbon ceramic brakes: https://youtu.be/B2Hl4c1iZK0?si=bCLQnfovjY7t-eYm&t=900
400kW regen is going to be a fairly alarming level of stopping for a normal vehicle. It's OK to leave emergencies to the friction brakes.
The idea is deleting the friction brakes entirely, saving costs, maintenance and weight.
And 400kW isn't really all that much for a sports car. I remember 911 ads from the '80s that boasted "brakes with more than 1000 horse power".
So how do you stop then if the batteries are (close to) fully charged? You'd need to shunt that power into a big resistive load, and then dump that heat.
> can a car with 200kW propulsion have a 400kW regen
At the motor level it should be the same, in propulsion you’re converting current to torque and in regen you’re converting torque to current, with the same hardware. The high voltage wiring is the same and will set the same limit on current regardless of direction.
I believe bidirectional inverters are generally symmetrical as well, so that should not be a factor.
Which I reckon leaves two factors:
1. Battery C rates, afaik pretty much all chemistries have a higher discharge rate than charge rate, especially when trying to maintain them for a long time, so by that account regen power would at most be the same as propulsion (if the entire power train is sized for the battery’s charging rate).
2. Artificial limitations, obviously you could always artificially under-prop, though that seems unlikely outside of niche applications.
tldr: I don’t think so, except on a technicality (that you can artificially hobble propulsion).
How far fetched is the idea to use Super-Capacitors to take up the energy generated by braking and then slowly feeding it to the battery at a rate that it supports?
The energy density on super capacitors is pretty bad. If you imagine full power 200kW braking for 5 seconds that's 1 mega joule and at a best case 8 watt hours per liter you're going to need 35 liters minimum. Really you probably need to double that so you can float up and down and never fully saturate the capacitor as power inflow is going to drop as you get closer and closer to fully charged.
Am I reading you right that breaking power (that you want to regenerate in the system) >> speeding power? Obvious now I come to think of it, and still pretty nifty new thing learned if true!
Seems like China is using them in buses already?
https://english.cas.cn/newsroom/cas-in-media/202606/t2026060...
The main benefit here seems to be smaller and lighter for the same power output.
Four years ago, when YASA's invention was discussed on HN, it attracted very little interest. Mercedes apparently saw more potential and decided to invest.
https://news.ycombinator.com/item?id=31701133 Inside Yasa: how a British firm is revolutionising electric cars (2 points | 0 comments)
Roads? Where we're going we don't need roads.
Only slightly related but does anyone know anything about motors with magnetic bearings? As in, no contact or friction. I'm looking for a hardware project
There are fluid dynamic bearings which were used in VCRs and probably hard drives and definitely laser printer mirror motors - two sets of precise herringbone patterns cut into the ID of a bearing column and a tiny bit of oil that gets entrained between rotor shaft and that bearing column. As the motor speeds up the oil forms pressurized donuts. Only works at speed and generally only useful when there aren't side loads so applications are limited. Rolling element bearings are a quite developed technology and hard to beat in most applications.
Closest I can think of is flywheel "battery" storage tech many of which do have magnetic bearings and also some way to get power in and out of the flywheel so basically a motor. It's not exactly what you're looking for but there's prior art out there.
maglev but those do linear acceleration instead of rotational. seems tricky though for cars with such uneven surfaces.
I wonder if that is even possible since the whole point of the motor is an imbalance of magnetic forces.
According to Claude it requires active control. So complicated and only used in very niche applications.
Theoreticaly the rotor could float on top of the stator, although It it would have to be always on.
I would guess that hydro and other generator forms would benefit from this design as well?
Personally I’d love to see this make it’s way into power tools and CNC motors.
Probably not. A huge disadvantage of axial flux motors is they have a large number of poles, which means that they get less efficient at high speed because they require say 5x as much switching.
This makes them kind of unsuitable for power generation and really high power motors (despite their power density) where the main way you get more power is just to spin really fast.
The other disadvantage is they have such a low amount of material in them, that the stator overheats really easily. And the topology of the motor makes it really difficult to get the heat out efficiently, which again limits their maximum power.
For a century Germany's comparative advantage has been [mechanical] engineering. As a European I want (need?) Germany to succeed. Ergo: more of this, please.
Their advantage was mechanical engineering. They have historically not done well with electrical systems. So this is a change - hopefully for the better.
That's not quite right.
For example Siemens and Bosch are large enterprises specialised in industrial scale electrical machines and parts (among other fields).
Infineon was spun off from Siemens 25 years ago an plays an important role in chip manufacturing for automative systems.
Electrical auxiliary stuff used to be and maybe still is a source of trouble. Power electronics should be fine, there's plenty of know-how available in the country, and with any luck, car companies won't have time to home-grow a mismanagement structure to fuck it up like they did with software.
Software and battery cells are the main challenges.
That is such a cool name!
Only if they could mass produce flux capacitor.
There isn't going to be a lot of improvement in overall EV performance/capability from better motors. Existing, boring motors are already close to 100% efficient, already small, and already powerful.
Advancements here chip away at margins, its nice but nothing to get super excited about. Whereas a modest ~20% increase in energy density from batteries would be amazing. Every little bit we improve there unlocks new capabilities. Towing long distances, smaller affordable economy cars and sports cars, airplanes, etc.
That is one angry looking car.
"axial flux motor" sounds like good progress towards the flux capacitor we've been waiting for
This is gonna be wild in a few years when these things are parted out the way tesla motors have been… Everything about these is crazy!
If you’re not caught up https://youtu.be/m507ryWhc6c?si=Hq3dfjXYxEIlYzeo
I am speculating but here might be reasons axial flux motors have advantage over radial flux motors:
1) torque: torque = applied force x length of the lever. Because the radial flux rotor must fit inside the stator, therefore radius << motor outside diameter. With the axial flux motor, the rotor is adjacent to the stator, therefore radius < motor outside diameter. Axial rotor radius > radial rotor radius.
2) space efficiency: in a radial flux motor you have 1 rotor, the coils arranged so that one end of the coil's magnetic field is useful to work on the rotor, the other end is not used. In an axial flux motor, (1) pancake rotor at each end of the coils, total (2) rotors, the coils can act on a rotor at each end. There is no free lunch here, to do useful work you still must provide more energy to the coil, but you can get the most from the space.
There must be someone here with a better handle on the electromagnetism, please correct me where I err.
Ah, another fantastic British innovator (YASA) having to realize its potential (and ultimately the downstream economic benefits of commercialisation) abroad.
Brought to you by the only country to have a space programme and abandon it.
Britain didn't abandon it's space programme. It abandoned a launch rocket programme though. That was over 50 years ago and the rocket was less capable and more expensive than alternatives at the time.
What alternatives? By your logic only one country should have a launch rocket. Thankfully that’s not a world we live in because that makes no sense. But I’m happy for you if you can be content with a space programme without a rocket, that’s a nice low bar to live with, you can basically never miss.
> Brought to you by the only country to have a space programme and abandon it.
I mean, so did France; they both essentially folded theirs into ESA.
Did they have to? My impression is British companies sell out as soon as they can these days. Is this something that could be changed with policy? Does Germany incentivise running companies more? Or is this cultural, e.g. British people are more risk averse?
I suspect it has more to do with Germany’s industrial scale in the automotive space (as opposed to incentives or culture).
Yeah. Traditional car makers have enormous demand for EV innovations. Germany has more and bigger traditional car makers.
It's very difficult to raise late stage capital in the UK, especially for deep tech. We invent so much but our capital ecosystem is all tied up in land and our pensions providers don't want to know.
The UK is by far the best country to raise venture capital in Europe, and is the third largest market in the world after the US and China...
> UK is by far the best country to raise venture capital in Europe
For late stage? Continental Europe has its banks and industrial policy. America and China have their deep pockets. Scaling out of the UK is incredibly hard, doubly so post Brexit, that’s why they sell early.
I think continental Europe has nothing on the UK when it comes to banks and financial markets. The UK has the deepest pockets in Europe because it is a hub for global capital. Brexit does not seem to have made a difference:
https://www.uktech.news/funding/late-stage-funding-surges-as...
Regarding AI (since that's the hot thing of the day), but IMO indicator of where the money is:
https://digital-strategy.ec.europa.eu/en/library/funding-ai-...
[In the EU] "Most late-stage capital comes from the US and UK."
Now, regarding YASA, it isn't surprising that they were acquired by a car manufacturer. And, well, the UK has virtually none at this point...
>Continental Europe has its banks
UK has City of London that dwarfs the banks of continental Europe. we're talking big banks, Fintech, HFT, etc. When you deal with Austrian banks you realize they're 10-20 years behind the UK.
> and industrial policy
Continental Europe has a large but somewhat inefficient(compared to Asia) and heavily subsidized industrial policy, acting more a a jobs program for politicians chasing votes and state subsidies, that the UK gave up on during Thatcher(for better and worse), and stayed in the niche, low volume but highly important aerospace and defense parts that dwarfs that of continental Europe.
Ofc that also means the labor market in UK is very K-shaped. Highly paid skilled niche jobs in London and the university research centers, and then a wasteland everywhere else.
I think Germany has tax rules that make exits harder, whereas it's very easy in the UK to sell. If you have a more free market next to protective ones it makes sense that your IP is going to flow in that direction.
It’s cultural. It is not difficult to raise a lot of money in the UK. The problem is that the UK (government, investors, employees and employers) got so high on the margins of services and finance in the 90s, that it has never recovered from this all-consuming addiction. Everything else simply attracts no interest comparatively, economic diversification be damned.
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It remains to produce the flux capacitor for time travel now :P
10 years behind Tesla, they are doomed
... Eh? No. No current large-scale production car uses axial flux motors. You're talking concept cars, plus a few oddities like https://en.wikipedia.org/wiki/McLaren_Artura
I mean in EV's, a fancy expensive concept motor isn't going to help, autonomy should have been their direction 10 years ago, they are on the downward slope of their existence im afraid. Its the equivalent of Blockbuster adding a tape rewinding service to try and boost sales vs Netflix streaming.
That is also not guaranteed. VW (with its array of brands) leads the european BEV market by a lot. [1] (sorry I only found data for April 2026 right now but earlier months were similar)
One additional point of data. In Q1 of this year they delivered 200K BEV worldwide [2] while Tesla did 350k [3].
Calling that 10 years behind is not warranted in my opinion. I would agree to say competitive and challenged.
[1] https://cleantechnica.com/2026/06/01/europe-ev-sales-report-... [2] https://www.volkswagen-group.com/de/pressemitteilungen/volks... [3] https://ir.tesla.com/press-release/tesla-first-quarter-2026-...
Volume alone is a bad metric, Tesla makes profit on their EV's sales Mercedes makes a loss, not sustainable.
Never become dependent on doing hideously complicated things. You will eventually struggle to choose to do something more efficient, as the european auto industry is currently displaying. The car where thid motor will be used will, given current market sentiment, be a massive flop. Here they are showing off how complex the manufacturing process is. Surely we’d all be better off with simpler and cheaper processes.
This entire product is easier to build than the existing technology, has more simple tooling and will be simpler and cheaper.
Designing the manufacturing machinery is exactly what happens in any manufacturing process. Those robots are general purpose that have been adapted for the required tasks, that's a normal process.
Why would you build a motor that's twice as heavy with copper and much wider when you don't need to?
China is working on the same type of engine: https://interestingengineering.com/ai-robotics/chinese-axial...
Ye, and I’d wager China will put that motor into affordable vehicles first, not some BS AMG GT 4 door/4 seat hyper car.
Mercedes always brings their latest technologies to the highest tier of cars first. Almost every major innovation has first debuted on the S class
Efficiency and cost savings at scale usually involve an increase in complexity: in mass manufacturing, complexity is generally a fixed cost and so can be amortized over larger volumes.
A typical modern car is already hideously complicated and a different type of motor would not change this.
What is the current market sentiment? Share of EVs is slowly rising so having a good motor as important as ever.
He says, typing on one of the most hideously complicated things humanity has created.
By that logic we should all just be writing assembly manually. Screw hideously complicated higher level languages. Screw LLMs in particular, so complicated!
> Never become dependent on doing hideously complicated things
Is Mercedes stupid?
How did Carl Benz dare to do something as hideously complicated as building the first gasoline-powered car in history?
And why did they kept inventing complicated stuff that ended in all modern cars like ABS, adaptive cruise control, direct fuel injection, emergency brake assist, etc, etc?
Not all of those inventions are bad. But not all of them are coming from a place of necessity. All of them do increase complexity. My gripe with Mercedes is not that they are constantly pushing boundaries on what can be done with more tech. My main gripe is that the EVs they are building are essentially as complex as the ICE cars and follow largely the same design principles as the ICE cars. For instance, in the EQS, instead of applying engine breaking when the driver takes their foot off the pedal, they went to great lengths to _move the break pedal_ in proportion to the amount of engine breaking that is currently being applied as per the VCUs command. And yet the door cards on the EQS are not up to the standard of an S class.
My main gripe with MB is that they have this new technology that could simplify things and let them build a better product. Instead of building around it, they shove it in to their existing designs. I was expecting an electric S class to be more akin to a Lucid Air sans the teething problems of a new company. Instead, we get weak attempts at solving non issues.
And whilst they are certainly not in the market of producing affordable vehicles, I would hope that using EV tech they could create a better version of their existing fleet. I do not think anyone buying an A class cares about the 4 popper under the hood - losing it and simplifying radically, in my mind at least, would give them more budget and leeway to create a more compelling product.
> "instead of applying engine breaking when the driver takes their foot off the pedal, they went to great lengths to _move the break pedal_ in proportion to the amount of engine breaking that is currently being applied as per the VCUs command"
There may also be a sports-related reason for people who habitually left-foot brake.
It depends how much you draw from the motor/generator. One can modulate it as they want, whatever can't go into the battery due to chemistry or drive constraints can be disposed of as heat.
You clearly have never used a car like that. You develop muscle memory for where the pedal is - finding that the pedal is not where it used to be does not inspire much confidence.
Every other manufacturer has managed to control regen breaking via throttle modulation - even ICE hybrid cars have been doing that for ages.
I've used left-foot-braking in my (ICE-powered) daily driver for years.
Regenerative braking is very different to taking your foot off the accelerator in a conventional ICE car, it's much more powerful a stopping force than traditional engine-braking.
I understand the rationale for moving the pedal to illustrate the amount of "braking" force. I'll admit I'm not exactly a typical driver though.
Why not move the gas pedal too, when using cruise control then?
They used to, but not by design. Back when throttles were still cabled I could feel the cruise control doing its thing by lightly resting on the pedal.
> "Why not move the gas pedal too?"
If you push the gas pedal, you'd expect to go faster, wouldn't you?
The equilibrium of "good enough vs technological simplicity" for cars was probably reached in the 1950s. Everything after that was more or less solving "non-issues" with ever-increasing complexity ;)
And why had that cars be to be refueled in pharmacies?
https://de.wikipedia.org/wiki/Datei:Wiesloch_Stadtapotheke_E...
Great, they finally started mass-producing 19th century technology, let's cheer that! Nowadays, while Chinese and Americans are producing GPUs, AI and li-ion batteries, German high-tech is an engine invented by Faraday
