alt Hacker NewsCould 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
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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.
> 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.
But EVs are already heavy because of the battery. I suppose percentage-wise the motors don't make much of a difference (?)
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%.
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.
I'm more excited about light electric vehicles. (Bikes, tuk-tuks, what-have-you).
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.
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.
> 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
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.
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.
saving 30 kg of weight on a 2000 - 2500 kg car won't lead to "significant efficiency gains"
> 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.
> 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.
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.
>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.
> 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.
It will probably lead to cars that fail sooner and are cheaper to build
> 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.