Comment by davedx
5 days ago
Could lead to significant efficiency gains for EV's, because 1/4 of the motor weight means better power-to-weight ratio... a lot of things will automatically get better.
YASA was founded in 2009, a spin out from Oxford University following the PhD of founder and still CTO, Dr Tim Woolmer.
"Over the decades that followed both of these technologies were explored. But despite the potential for weight reduction, smaller size, shorter axle length and increased torque, it was the difficulty in manufacturing the axial flux technology that limited its commercial viability, because the motor could not be made by stacking laminations, as with radial machines."
"The breakthrough innovation came by segmenting the axial flux motor in discrete "pole-pieces", so the motor could be manufactured using Soft Magnetic Composite material.
SMC can be pressed at low cost into a wide variety of 3D shapes. This removed the need for the complex laminations, overcoming the major manufacturing challenge of the axial flux machine."
"In 2025, after a £12m investment, YASA opened the UK's first axial-flux super factory, in Oxfordshire.
The opening of this facility boosts YASA’s manufacturing capacity, setting new benchmarks in e-motor technology and quality, and enabling production to scale beyond 25,000 units per year."
This is awesome. Lighter motors also make electric flight more viable
> Could lead to significant efficiency gains for EV's, because 1/4 of the motor weight means better power-to-weight ratio... a lot of things will automatically get better.
EV motors are already lightweight. The electric motor in a vehicle like a Tesla Model 3 already weighs less than you do. Reducing that one component by 75% would be a weight savings equivalent to about a half of a passenger.
Not a significant efficiency improvement for vehicles that weigh over 3000lbs (or double that for many EVs).
Every little bit helps, but this isn’t a game changer.
This, or a miniaturized version thereof could change the game for light electric vehicles - imagine an electric motorcycle that weighs substantially more like an electric bicycle.
Right now it takes about 10-15lbs of motor to produce a 3KW motor for an electric bike, this motor is about 10 times that in power density afaict.
The Livewire electric motorcycles use something like 100-200 lbs of motor to produce 1/4 as much power, 75kw, so that’s an improvement of 8-16x.
Does this motor design scale down? It's not clear from the article - the article focuses more on the relative efficiency gains over the previous model.
A 30lb 1000hp motor doesn't necessarily mean that they can also produce a 3lb, 100hp motor. It would be cool if it did, but I doubt that it does because usually component strength doesn't scale linearly.
That being said, these are still valuable for traditional EVs. Even if they are only a modest weight savings in the grand scheme of modern vehicle weight, their ability to improve packaging options will be a boon. One thing the industry has dicovered is that the generic "skateboard" platform doesn't make for the best vehicles, in terms of packaging.
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Electric pedal bikes are already at the limit of what their chassis’s support even with small motors.
10kw+ is comparable to starter gasoline motorcycles in the US (or midsize motorcycles elsewhere) capable of going on the highway. At that point, you need to start scaling everything, like brakes, tires, and the size of the chassis.
The livewire has a motor large enough to drive a car.
The problem for electric motorcycles is the battery weight.
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> This, or a miniaturized version thereof could change the game for light electric vehicles - imagine an electric motorcycle that weighs substantially more like an electric bicycle.
Sounds terrible for every other user of paths currently.
There’s no area in the world that allows e-bikes with more than 750w motors. A 3kw motor is illegal (cf Surron), unless you are talking about an e-moped requiring registration.
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Not a game changer but I wonder if ligher motors allow you to do things like have one motor per drive wheel, removing the need for differential gearboxes?
Then you can do clever things with traction control without having to use the ABS system to brake the drive wheels.
Or dramatically change the turning circle on big cars and vans. Maybe even reduce the size and weight of the braking system by taking on some of that role.
All for the same weight budget.
I believe that some EVs already have 1 motor per wheel such as the top of the line Rivians that are advertised as quad motor.
Putting the motors in the wheel is bad for a separate reason: Unsprung weight.
Every ounce you have in the hubs that don't float on the suspension reduces certain suspension attributes. You end up with a crappier ride and poor performance.
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https://www.mbusa.com/en/vehicles/model/g-class/suv/g580w4e#...
has four electric motors
If you're putting motors in wheels, lower weight means reducing the weight/capacity of adjacent systems.
Lighter motors for mobile robots could also be cool.
Nice observation that the weight isn't that much of a deal compared to batteries for electric vehicles!
It does seem like with this advancement, and the size of these axial flux motors that maybe, all wheel drive vehicles will be the default. As well as sub 3 second acceleration, which can make vehicles safer, for example getting out of the way of an incoming object. Of course it could also make them less safe because that vast of acceleration is kind of dangerous.
But I do wonder if the weight reduction (over 30%) of lithium sulfur batteries paired with these is really going to make a great recipe for all sorts of quiet, long lasting, powerful electric vehicles and robots!
Exactly. Main problem is battery energy density. Cars can drive about 20 kilometers on 1 liter of gasoline. In comparison, Tesla's 4680 cells are at about 272-296 Wh/kg and CATL's Kirin Battery at about 255 Wh/kg. A bit efficient EV often uses 200 Wh/km, so for 1 kg of battery the electric vehicle can only reach 1-2 km. An order of magnitude difference. Theoretically, batteries could go to 1000 Wh/kg some day, which would mean about 5 km per 1 kg of battery assuming all else remains equal.
https://ev-database.org/cheatsheet/energy-consumption-electr...
The Model 3 manages < 140 Wh/km, and many seem to be under 150/160/170.
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Oranges to apples so long as electron mass is fixed and reserve currencies fluctuate.
Somebody's probably already pointed this out, but in the case of motors, making them lighter can make a big difference.
For example, by making the flywheel in a clutch lighter, you reduce the amount of torque it takes to spin the flywheel. Saving 10 pounds there is not a 10/3000lb difference.. it could be a huge percentage of total power output.
To be precise, the impact of mass inside the rotor of the motor is 2 * the mass * the rotor diameter / the wheel diameter * the drivetrain gear ratio.
For a typical EV, I think that works out to a factor of around 2.
Basically Amdahl's law [0]. If optimizing for weight, go for the components that make up most of the weight first.
[0] https://en.wikipedia.org/wiki/Amdahl%27s_law
I would expect that lighter motor components would potentially allow weight reduction in load bearing components. Not an advantage for SUV-type cars, but for light and ultralight vehicles it could add up to more weight saving and longer ranges.
You still have to handle the torque of the smaller motor. 30kg is maybe 2% of the vehicle weight.
Then for drones ?
> The electric motor in a vehicle like a Tesla Model 3 already weighs less than you do. Reducing that one component by 75% would be a weight savings equivalent to about a half of a passenger.
Of which there can be two, or even three.
For EVs no but it's huge for flight if it could be scaled down. Paramotors and ultralight planes are on the verge of being competitive with gas they just need a bit more energy density per pound in the system.
Maybe this would be good for a personal quadcopter, however the batteries weight would probably make the motor weight savings unimportant.
The difference is when you take into consideration rotating mass, and the distribution between the stator and rotor.
It drops a buck fifty per motor. That IS a game changer.
It can make cars cheaper, or longer range, or faster, or any number of other designs based on what the manufacturer is looking for.
But to OP's point about flight - stacking 6 Tesla motors is not an option. Stacking 6 of these YASA motors? Much less weight.
Looks like it’s about 45 kg for a Tesla and 13 kg for this one. It at twice the horsepower. So maybe 8-10kg for a down rated model. IIRC, axial motors need their diameter to retain their efficiency advantage so a down rated one would likely be lighter but close to the same external dimensions.
But that’s still a lot less rotating mass, and might make multiple motors attractive again.
> It drops a buck fifty per motor. That IS a game changer.
You’re reading their marketing material. You have to think of this like all of those PR releases you’ve seen over the years about new battery technology that is 4X smaller or new hard drive tech that is 10X more efficient. The real world improvements aren’t going to be as big as their one lab test.
A Model 3 motor is already well under 150lbs, unless you start including ancillaries like the inverter and power transmission parts.
They’re not dropping “a buck fifty” from typical EV motors.
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Range in EVs is impacted very little by weight
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I wish more people on the road realized the extent to which weight reduction improves all aspects of the driving experience... it really does compound unlike any other change that you can make to a vehicle. IMO heavy vehicles are a scam and the antithesis of the direction we should be moving.
I agree with you however I believe weight and safety are in a complex relationship right now, which has nothing to do with performance and handling.
Unfortunately I feel much less safe in a Fiat 500 when a significant portion of cars in the road weigh nearly 3 tonnes and perhaps can't even see me. I suspect most people are in SUVs because they're the pragmatic trade off between safety and convenience, not because they were hoping for excellent performance.
Yup, it's an arms race to see who can buy the biggest vehicle so that they can see over the second biggest vehicle and survive a collision with it.
But small cars are only unsafe because of that discrepancy between the largest and smallest cars, and it's not just weight, but height difference. It's possible to survive crashes at very extreme speeds in very light cars if they are designed to work that way (see: F1 crash g-force). Not so much if you literally get run over.
The culture needs to change. A vehicle is not a living room. The driver's seat is not a sofa. You don't need a TV in the dashboard. You don't need 8 seats when 7 of them are unoccupied 90% of the time. You don't need to go into debt to buy a land yacht.
So yeah... you're right, but it's a bummer that we've arrived at this situation.
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Your intuition is correct.
Americans’ Love Affair with Big Cars is Killing Them (https://www.economist.com/interactive/united-states/2024/08/...) - The Economist.
> In a crash, the fatality rate of the occupants of the heavy pickup truck is about half that of the compact car. But they are also far more dangerous to the fatality rate of people in other cars.
> The fatality rate is roughly seven times higher when colliding with a heavy pickup truck than with a compact car. As the weight of your car increases, the risk of killing others increases dramatically. For every life that the heaviest 1% of SUVs and trucks save, there are more than a dozen lives lost in other vehicles.
Unfortunately car safety is only evaluated in terms of safety for the occupants. Not safety of society.
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Classic prisoner's dilemma.
Everyone who can will naturally choose "defect" unless there's some sort of external coordination mechanism.
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I wonder if larger/heavy non-commercial vehicles were taxed at a very high rate, would more people choose Fiat 500 sized cars?
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Tax SUVs out of existence.
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Weight is not the only thing that matters though. You also need to consider center of gravity and wheel base. A YJ Jeep Wrangler and a Honda Fit both weigh around 2700 lbs and they even have similar wheel bases but the driving experience between those 2 is night and day. A Honda Fit can take a turn at speed without feeling like you're going to go flying. You'll feel like you're able to flip making a turn going 20 mph in a YJ.
This is why the first performance mod that most people put on their cars is an adjustable coil over suspension. Dropping the car down by an inch or 2 changes has just as much of an impact as shedding some weight.
Ironically, most people put lift kits on Jeeps but that also usually comes with widening the wheel base and putting on larger wheels/tires.
Lifting an off road vehicle isn't ironic at all, nearly every characteristic that makes a vehicle good on road makes it bad off road and vise versa.
Increased height makes for increased ground clearance and improved break over angle. Sway bars are another suspension component that's great for reducing body roll on road at speed, but reduces articulation and ground contact off road. Differential lockers also negatively impact turning radius, and cause tire chirp, wear, and oversteer under throttle on road, while increasing traction off road.
What's silly is daily driving an off road vehicle on road, especially if you never take it off road.
You are correct, ideally you would do both. My car is lowered on coilovers, I also have front and rear sway bars, but weight reduction is so much more than just handling.
I didn't realize that Jeep was so light... pretty nice actually, but yeah, that's just an application mismatch. People buy Jeeps that will never see even a dirt road in their lives. Then they get on a dirt road once or twice and say, "Look what it can do!" Sure... a rally car would be much better. In order for the Jeep to come into its own you need to be doing something that requires ground clearance... that's basically their singular purpose: rock crawling (which almost no one does).
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> Ironically, most people put lift kits on Jeeps but that also usually comes with widening the wheel base and putting on larger wheels/tires.
That's not ironic. That's just caring more about the looks and you like that look. And looks > handling for that person
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Absolutely and on top of that far lower pollution from tyre and brake dust, and less damaging to the road top surface.
The weight difference would make an unmeasurable difference in those things.
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Driving Volkswagen e-up for the first time was a very unique experience to me. My brain needed to adjust that a car can be that nimble and responsive due to its small size/weight and instant torque from the electric motor.
I went from a 2021 Opel Mokka (4.2m long, 1350kg) to a 2024 Volvo EX30 (4.2m long, 2000kg).
It was an absolute shock the first time I braked in the Volvo, not to mention trying to take a corner.
> I wish more people on the road realized the extent to which weight reduction improves all aspects of the driving experience
This is a blanket statement and completely untrue. Good driving experience is directly correlated to TRACTION, not just weight. And traction isn't just a function of weight - it also is affected by center of gravity, friction between the wheels and the road. Traction is what gives you the perception of being in control of the car.
I used to own two cars of the exact same model - one petrol and one diesel. The petrol is lighter in weight, about 100+ kgs lighter than the diesel variant. And the driving experience on that is slightly scary especially on roads with strong winds. In fact, it is so light that if you drive over tiny puddles or rumbles strips, the car will sway sideways. The diesel always feels more planted because it is front-heavy, thus adding more traction to the front wheels (both are FWDs). I always prefer the diesel for longer drives because of the heft and confidence it provides.
I get what you're saying, but tire technology has improved traction so greatly in the last decade that we can definitely take the slight loss in maximum theoretical traction for the massive benefits in other areas. There is also the question of what "maximum traction" is... what scenario are we talking about? Straight line acceleration from a dig or skidpad turning at a high speed? If we're turning at all then the momentum (which increases w/ mass) of the vehicle is what pulls it off course and causes the tires to break traction.
I also drive a FWD (a quite spicy one) and I break traction all the time, not because of weight, but because of torque. You can modulate torque, not weight. The biggest traction increases that I made on my FWD were when I put on sticky summer tires, the second was subtly changing front control arm geometry and bushings, and the third was adding stiffer engine mounts.
Agreed on getting tossed around in a light car though, not much can be done about that... other than making the roads better and lowering the center of gravity.
It's ~all battery weight, though. This doesn't really move the needle.
Curious what you mean? Surely more weight moves the weight needle?
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> In 2025, after a £12m investment, YASA opened the UK's first axial-flux super factory, in Oxfordshire.
It’s a little sad to me that fundamental innovations in electromechanical engineering like this get just a few million in investment, yet if this had been yet another derivative software startup with “AI” in the pitch, they’d probably have 10x+ or more investments being thrown at them.
Seems to me everyone wants to invest, instead, into something that can be "web scale" with low marginal cost, that is, natural monopolies. There is not enough anti-trust enforcement.
They should have named their company "YASAI" (pronounced as "Yes AI") and just watched the investments roll in ...
They're owned by Mercedes, I'm sure they probably have access to the capital they need.
Factories take time to build. "Investors" want a get rich quick scheme.
Or maybe it's not as important as they make it sound.
Welcome to the UK and its innovation hostile environment. We don't have the US culture of throwing VC money at things and seeing what sticks.
This is less UK vs US, more hardware vs software.
But EVs are already heavy because of the battery. I suppose percentage-wise the motors don't make much of a difference (?)
The issue with this type of motor is that it is part of the unsprung weight since it is inside the wheel. This is probably why savings here matter a lot more (or at least in a very different way) than the battery weight.
Ok, now I understand why this motor is only used in supercars - installing four (or even only two - according to https://www.mercedes-benz.de/passengercars/technology/concep..., even the AMG GT-XX has "only" three of them) hub motors with twice the power of a Tesla Model 3 in any other car would be ridiculous. So, the actual challenge is to make this motor even smaller while keeping the same power to weight ratio, so it can also be used for regular cars? That is, if they want to build something for the mass market, not only for an exclusive clientele?
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YASA doesn't call it a hub motor specifically but that's one place where it helps to save as much weight as possible. And for the cars most likely to have 1000+HP weight matters too. A Tesla motor weighs 100-200lbs, so saving that much weight down to 28lbs on a supercar is highly desirable.
I think large drones will be another place where a downsized version of this motor will make a huge difference, assuming the power scales nicely with size.
I might be wrong, but I don’t think these motors are intended to be used inside the wheel. That would add a ton of additional requirements in terms of physical durability as well as constrain optimal torque and RPM of the motor design.
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Why would it have to be unsprung? They are not unsprung in the vehicle shown in the article.
> This is probably why savings here matter a lot more (or at least in a very different way) than the battery weight.
Wouldn't that make it worse or just ... different. Before this the unsprung weight wouldn't have had a motor in there and now it does. Increasing the unsprung weight doesn't seem a like a good thing.
What current mass production EVs use hub motors? It seems a lot more sensible to have the motors inboard, mounted to the chassis, and drive the wheel(s) with axle shafts. It seems in my searching this is how nearly all EVs are currently designed and produced.
I believe caring about unsprung weight only matters for handling not efficiency
See also the Saab Emily GT project. Even with an older, heavier gen of these axial flux motors they found significant performance gains by controlling each wheel via its own motor.
https://electrek.co/2023/04/27/saab-engineers-develop-secret...
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Where does it say it’s inside the wheel? Not sure about that
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It compounds. If you have a lighter more efficient motor you need a smaller battery for the same range, that combined weight loss means you meed lighter brakes etc etc, and because the car is now lighter you size of your motor you need is less.....
They claim, this compounding effect works out to basically double the effective weight saving from battery and motor.
ie if you start with saving 50kg on motor, and 50kg on battery, you end up saving 200kg over all. Still only about 10% of a typical electric car.
https://youtu.be/3qjB6GnhloY?si=yqlz7Evuyf5VaghO&t=446
> If you have a lighter more efficient motor you need a smaller battery for the same range
Nitpick: You can have a lighter motor, but you're never going to have a significantly more efficient motor because existing EV motor systems are already 95% efficient or better. The electric motor is an old and refined technology.
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What's a bit of a shame is they are no longer an independent company ( ie wholly owned owned by Mercedes ) - so that might mean we are less likely to see these motors combined with solid state batteries any time soon.
https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation
Yea that's the thing right, the battery is so very much of the weight that optimizing the other parts are "meh" at this point. What is cool is that the 600Wh/kg solid state batteries seems like they are really finally here soon :) i.e removing 200-300kg from a car in one go will be a game changer.
No wonder electrics don't sell well in the US. People weigh more, you're basically saying that leaving grandma at home, is a "game changer".
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Manufacturers may just keep the battery size and market the improved range instead? Smaller cars in urban and suburban environments have always had lots of benefits, but since many of them are collective in nature, it has largely fallen on tragedy of the commons, and we got larger cars with larger hoods instead.
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Not true. Tesla themselves said the way they got the Model 3 to be so efficient was by optimising every single part exhaustively. It’s expensive at design stage but results in the most efficiency gains across the fleet - so worth it (especially something like the motors)
Tesla Model Y's battery is 771 kg. The motor in Model Y weights about 45 kg, about three times as much as the motor in the article. By reducing dual motor configuration weight from 90 kg to 28 kg, we reduce total powertrain weight by 7%.
The new motor is also much more than double the power output of the Model Y motor, so the second motor and its wiring could be eliminated completely.
No, because that second motor gives you AWD. Sure that's a feature you could go without...
But torque and power were never the limiting factor for an EV. You would only benefit on a track, and if you're taking a model Y there...
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You’d need to add back in an all wheel drive powertrain. A typical drive shaft is 20 to 50 pounds (9 to 23 kilograms)
The motor is high torque, so I’d expect the drive shaft to be on the heavier end of that.
I’m not including the other power train components, but it’s easy to imagine it all adding to more than the weight of a second engine + wiring.
Also, having one more complicated power train is probably less efficient than two simpler ones, which implies a bigger battery.
And shouldn’t it be possible to make the battery smaller with a more efficient motor?
It is not indicated anywhere that this particular motor is more efficient than older ones in terms of the electric force conversion.
This new motor is more powerful, that's it.
Nothing was said about cooling or voltage requirements. The latter is important because higher voltage is more dangerous to work with or be near.
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The battery could be made smaller by whatever amount is needed to carry the marginal motor weight the advertised distance.
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> Could lead to significant efficiency gains for EV's
Not really. EV's are very heavy from non-motor weight. A Model Y weighs ~4300 lbs. A motor that is 75 lbs lighter is a 1.7% savings. That's not nothing, but I wouldn't say "significant". You can do better by swapping for fancy wheels or eliminating some of the glass roof.
And really this is true up and down the electric vehicle world. Weight-sensitive applications are always going to be completely dominated by battery weight. Making the motor smaller just isn't going to move the needle.
Basically this is good tech without an application, which is why it's having to tell itself with links like this.
It’s great anywhere you want more power but are limited by space and/or weight for performance reasons. Aerospace, e-bikes, electric race vehicles, electric motorcycles.
But yeah, EVs seem weird except for racing reasons perhaps.
What I can’t figure out is how they dissipate the heat - double digits kw per kg is crazy.
From https://yasa.com/technology/
The first step to dealing with heat at high kw, is to not generate the heat you have to dissipate in the first place. Which means chasing smaller and smaller efficiency gains, because that reduces heat generated.
The more of the energy going into moving the vehicle, the less heat the motor has to handle.
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Again, no, because the motor needs to be powered and the battery is vastly larger than the motor already in any of those applications. Even in RC planes, which fly for 5-6 minutes at a time, the battery is 5x or more the weight of the motor, wiring and controller logic.
Hub motors are problematic because they increase the sprung weight of the wheel, which loses more traction when hitting bumps. Dangerous while cornering or braking. Scale down a motor like this to 300 HP and you could have an amazing AWD vehicle.
This video https://m.youtube.com/watch?v=WU9Ptibu2WQ&t=179s claims that SMC materials have much higher losses at low frequencies than laminated materials, up to around 400 HZ when they very rapidly pull ahead.
So as the core of a step down transformer for consumer electronics, SMCs would be worse than a laminated core (stack of sheet metal pieces punched with a press, stacked and wound with the windings). But in a motor operating at 100s of rpms, no problem. And as I understand it, in high torque motors the magnetic fields pulse far more often than once per revolution because the windings are many and small, so that several can pull on the armature at any orientation.
This is a negligible improvement to most things about an EV. Motors are already extremely power-dense.
There is a single exception, and it's a big one. Direct-drive, wheel-hub motors are not well-regarded right now, specifically because they increase unsprung weight (the part of the car more closely coupled to the road surface than the passenger) and this impacts handling substantially. So instead we backport a bunch of the mechanical infrastructure that transfers power from a traditional ICE engine to the four wheels. We're paying that bill already, on almost all production EVs. Quadruple the power density and simple, 1-moving-part wheel hub motors look like a lot better case versus central driveshafts and mechanical linkages.
> Direct-drive, wheel-hub motors are not well-regarded right now, specifically because they increase unsprung weight
It will always be lighter to not have the motor in the wheel.
> So instead we backport a bunch of the mechanical infrastructure that transfers power from a traditional ICE engine to the four wheels.
No, we do it because it's smart and efficient for freeway-capable vehicles.
Wheels get banged up in use. They're easy to replace for different applications. They're exposed to 200 kph salt spray at hundreds of RPM. They are not a great place for motors.
I'm more excited about light electric vehicles. (Bikes, tuk-tuks, what-have-you).
...with 1,000 horsepower. =:-)
In fairness, ICE engines have been able to provide too much horsepower for those use cases for a long time.
Cutting the motor weight probably matters more for smaller vehicles than bigger ones though.
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> According to YASA, this is achieved without using exotic or expensive materials, so the design could actually be scalable once the demand kicks in.
That is ever more special
I'd expect more applications in either aviation or mobile / portable power devices.
As others have noted, battery remains a major factor in overall mass, and motor placement (in-wheel vs. driveshaft) is a concern in ground-transport.
In aviation, battery limits overall range, but a high-power, low-range, lower-mass vehicle could be useful for short-hop flights, manned or unmanned, especially where payload considerations are paramount.
Mobile-power applications (tools, transportable equipment) might also benefit from high power-to-weight, especially if this means that overall weight limits could be more readily met (e.g., total vehicle weight, total carried weight), or additional equipment (or battery) could be provided.
Better for robotics as well.
This may or may not be generally true. The needs around motors in a robot are more about control than raw output (some output is certainly needed). It is possible that this advancement in manufacturing will benefit there, but it is not assured by the information at hand.
Depends on the application to an extent but I agree there's not enough information available to be sure.
Batteries are the bottleneck.
Even if motors were literally weightless and mass-less, EVs would weigh more than ICE cars.
It's like making a more efficient CPU for your phone when all the power is eaten up by the cell-modem, screen and RAM. People wonder where the practical battery life gains are and theyre miniscule in practice
Only the absolute weight of a motor counts, because consumers of passenger vehicles do not require 1000 hp.
How far does YASA's tech allow the motor weight to scale down, for applications where you don't need the power?
Can you make it 2.8 pounds instead of 28, if all you need is 100 hp? Likely not.
The other aspect is that a smaller motor with the same power generally has higher efficiency, by necessity, since it has less heat dissipation. So higher power and higher efficiency and lower size/weight all go together. It’s a great synergy.
Is it always true that a smaller motor with the same power has less heat dissipation? It doesn't seem all that obvious to me.
All else held equal, I think so, yeah. If you have the same temperature differential, the same manner of heat dissipation, and a smaller surface area then that should mean smaller heat dissipation, yeah?
Obviously if you go from eg. a large air-cooled motor to a smaller water-cooled motor, then the smaller motor could potentially dissipate more heat, but that's a different scenario.
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>In 2025, after a £12m investment, YASA opened the UK's first axial-flux super factory, in Oxfordshire.
In Bay Area that is small investment in a startup which would be able to lease a small office
>Could lead to significant efficiency gains for EV's, because 1/4 of the motor weight means better power-to-weight ratio...
that would help VTOL a lot. Unfortunately YASA motors are priced for supercars and availability seems to be low. Until some factory in China starts making similar ones, there are not much chances on getting hands on such a motors.
OK, you can stop being so enthusiastic. We won't afford to buy any vehicles with these motors until the patents expire. I mean, I'm still waiting for epaper screens...
I don't see the weight reduction being very significant.
If we take a Tesla model 3, I believe it weighs 1611kg, and the motor shows up at 80kg if you google it (no idea if this is correct). This YASA motor by comparison weighs 14kg. So, this would drop the vehicle weight by 66kg out of 1611, so that's a 4% saving.
I assume that means it would be more like an 8% savings on the dual motor variants? At what point does it become significant?
This motor is well more than twice as powerful as the Model 3 motor, so it could eliminate the entire weight of the second motor in the higher performance models. That’s 146kg, the weight of two adults, an 11% reduction.
As pointed out elsewhere, this neglects AWD which is an important part of the dual motor models' value proposition.
> because 1/4 of the motor weight means better power-to-weight ratio...
1/4 of something that is a small fraction of the total weight of a car means very little improvement in overall power to weight ratio.
I suspect that gaining 40% of car seat weight would be much more beneficial even if way less sexy.
saving 30 kg of weight on a 2000 - 2500 kg car won't lead to "significant efficiency gains"
The Ferrari 296 GTB weighs about 1500kg and the sports version 1300kg. For the cars YASA produces motors for it's much easier to increase the power to weight ratio by reducing weight than increasing power. I imagine an important design point for all of its components is to reduce weight.
Also as mentioned by another comment, Mercedes produces Formula 1 power units, and engineers would kill for a savings of a few kilograms in Formula 1. Those savings are not easy to come by.
Weight reductions on an electric car are self-reinforcing. If you reduce the weight of a component, the battery can become (slightly) smaller, which again reduces weight. At a certain amount of reduction this will allow you to make the whole structure lighter, which will again allow for a smaller battery.
So yeah, weight reduction on EVs is great.
Also not considered is that the announcement is for 740bhp motor. The Tesla model 3 has a vehicle output of about 400 hp. I’m not sure of all the design specs, but it seems clear to me that a smaller version of these motors could suffice to drive a 3 equivalent vehicle at 1/2 the output and still be more than sufficient. So let’s say maybe 15lbs each, vs current equivalent 70lbs each. It’s not major total weight impact, but with battery advancements it will compound.
I think people are overlooking that the announcement is for a performance motor meant for the performance market at the moment because that is what the backers of YASA are most interested in because it has the highest margins and prestige. Also not mentioned is the efficiency from the simpler production line.
My impression from what I know is we are looking at an impact equivalent to direct injection engines; not revolutionary, but a major advancement of one component that has significant and consequential effects.
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> If you reduce the weight of a component, the battery can become (slightly) smaller
Suppose we have a motor that weighs half as much, but produces double the output power, but consumes 4x the input power (so, it is half as efficient).
How would that lead to a smaller battery?
Wouldn't we need the component to use less power if we wanted to shrink the battery, rather than just weigh less?
I agree insofar as the motor is not a Big Ticket Item, opposed to ICE cars where the engine block is going to be 10% or more.
Tesla (I know) claimed a 30kg (?) weight loss on their Cybertruck (I know) just from moving their 12V systems to 48V, allowing for lighter cables at lower currents. Not all such potential is untapped, and my hunch is that there is more to be had with structural battery integration, battery cooling, and high voltage wiring.
Depends on your definition if significance, but I think they do. Every kg of useless weight you do carry, lowers your range. But sure, on its own it is not a magic game changer for heavy electric cars.
For light weight vehicles on the other hand, it might be.
If you put several small motors on each wheel you might get some extra weight gains in the form of less transmission needed. Cables weight less than metal structural bars. But yes you are not going to be 500kg lighter.
There is no statement about the efficiency of the motor itself. If the energy conversion efficiency is low, then the weight savings will not matter and the car will have even less range.
> This is awesome. Lighter motors also make electric flight more viable
The next innovation we need is Aerial refueling[1] for electric planes. High density swappable batteries and high altitude wind/solar plants that can swap batteries mid air. Perhaps some billionaire will develop a large fleet of these to service all flights! If no western billionaires, we just have to wait for China to develop this tech.
[1]https://en.wikipedia.org/wiki/Aerial_refueling
A sufficiently compact electric motor enables mounting it in the nose-wheel of commercial aircraft, allowing it to be driven around like a golf cart. This means the plane can taxi without the use of its engines, just the power from the APU. [1]
Also planes would not have to wait for a tug to pull back from the gate, which improves turnaround times for the airline.
[1] https://www.wheeltug.com/
You could also spin up the landing gear wheels prior to landing to massively reduce the amount of rubber transferred from tire to runway on touchdown. Rarely done today because of the weight and complexity of adding motors, but letting the ground spin up the wheel is pretty expensive both for tire wear and runway maintenance
Apologies for the turbulence, we're just flying through a thunderstorm to top up the batteries
Or laser power beaming from a satellite, or a ground station.
Not very feasible, but an option that has been thought through.
I guess there’s a system that’s gated to track dependent technologies, to track improvements and what they’ll enable.
Surely it would be easier to recharge rather than swap batteries? I wonder if in the future war will be like a turn based strategy game as everyone wait for drones to recharge before making a move.
Mid-air: yes. A boom with a charging cable or even beamed energy would be much easier.
On the ground: swapping batteries is faster, and batteries are cheaper than planes or drones. You want the expensive part back in the air as soon as possible so you don't need as many of them. On the whole this probably also simplifies logistics: in civilian aviation airport space is limited, in wartime it's easier to transport one hundred drones and two hundred battery packs to the frontline than to transport two hundred drones
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I don't see it working like that in Ukraine...
Difficulty for swapping batteries too - how to differentiate between strategic bombings and a refueling accident.
It will probably lead to cars that fail sooner and are cheaper to build
Okay cool downvote me but it's true, most of the weight is batteries and asking a smaller device to do more work will create more heat and wear components faster. It's not a new phenomenon.