Permanent magnet motors sometimes use rare-earths. It's not absolutely necessary, but going without may lose some power and/or increase the weight. Induction motors don't need permanent magnets, but they're less efficient so the EV industry seems to be moving away from them. (Less efficient also means they generate more heat, which means more active cooling.)
EV motors often have absurdly high RPM limits, which may require some exotic materials and/or lubricants. (I think Tesla motors go up to about 18,000 rpm if memory serves.)
Copper for the windings is another high-cost material; copper has been expensive lately. You could use aluminum instead, but it would mean having to scale up the design or run at a lower power to compensate for the wire resistance.
I do hope to see good, cheap, powerful motors be a thing that was more available to random third parties to swap into their old ICE vehicles. Right now the best options seem to be to use something like a Netgain Hyper9, or scavange a drive unit out of something like a Leaf or Bolt or Tesla.
ok so based off your first three paragraphs what could justify all these mainstream car makers building motors that weigh 2.5X, use so so so much more material? why is Koenigsegg alone able to achieve such material efficiency, when it seems like we should be so pushed to push weight/material usage down down down? what justified such a high power density motor being so expensive?
For an electric car, the hardest part to design is the battery. It's really expensive, and really heavy. If you spend a ton of engineering effort to make your engine 50% smaller and $500 more expensive, all you've done is lowered your profit margin for a tiny decrease in weight. If you instead put the same engineering effort into the battery and manage to make it 5% smaller, you get a bigger weight reduction for the car, and it's probably accompanied with a lower price.
Optimizing things that aren't a bottleneck is almost never a good use of resources.
Yeah, that makes sense. EVs need motors and someone has to make them. Manufacturers will buy whatever has the best specs for the least cost that matches the vehicle. Some companies will naturally specialize on motors, even though motors are basically good enough already.
If this smaller motor is also cheaper because it uses less material that would be a win, but I suspect that's probably not the case. They also don't mention efficiency in the article, and that can be more important than size/weight.
I wonder how much Tesla pays for their motors. I wonder how much they'd save if they only needed 1/3rd as much material.
This kind of material-minimizing innovation seems like it could go a long way. It feels like if someone wanted to mass produce power-dense electric motors, they could radically reduce the cost of a motor by simply using less materials. If they can get to scale. If they can sell them like crazy, which they should, since they should be cheaper to make, as the material inputs are so much less.
Koenigsegg of course doesn't care about production costs. It's expected that every item that goes into the car is going to be built via the most exorbinant processes possible. But the underlying idea of using far less material to make a motor sounds extremely attractive to me.
I didn't see much in the article about efficiency. Koenigsegg seems focused on supercar performance like acceleration, but most EV makers care about range. EV makers do pay a lot of attention to their motors and highly optimize them for the specs that they care about.
The more efficient your motor is, the more mileage you get out of your battery, so the smaller your battery can be. It could easily be that an extra 1 kg of steel and copper shaves off 10 kg of lithium ion batteries.
The Netgain motors are wildly outdated. 100-140v in a world where 400v is almost standard, and 800v is increasingly common.
Means you need very heavy duty wiring/controllers, high current rated batteries, can't use OEM power steering / AC compressors, can't use OEM battery packs, can't use DCFC infrastructure....
And why not? Power steering systems don't run on the HV system but on the LV system as every electric car has a DC/DC converter that bridges the HV and LV domains. So regardless if your cars is using 800V or 100V powertrain system, all the auxiliary equipment will still be on the 12V network.
I basically agree with that, though I'd say that lower voltage motors are sometimes useful in conversions, since they usually have a smaller battery pack than what would be in an OEM vehicle (due to weight, cost, and having limited space to put the battery). Lower voltage doesn't really stop you from salvaging all those other parts from an OEM vehicle. I think it's usually just the motor controller and DC-DC converter that run at the full pack voltage. DC fast charging is a problem if the charger doesn't support the lower voltage.
I have wondered whether the Hyper9 can actually run at a higher voltage without damage. I suppose the limiting factors are the insulation on the motor windings and the ability to dissipate heat. (The motor demagnetizes if it gets too hot, which is why the motor has a temperature sensor so the controller can back off before that happens.) The Hyper9 comes with a motor controller that's limited to 180 volts (that's for the 144v nominal version). I don't know if anyone's tried to run a Hyper9 with a different controller that can handle much higher voltage, like 300 or 400v.
EV motors often have absurdly high RPM limits, which may require some exotic materials and/or lubricants. (I think Tesla motors go up to about 18,000 rpm if memory serves.)
Copper for the windings is another high-cost material; copper has been expensive lately. You could use aluminum instead, but it would mean having to scale up the design or run at a lower power to compensate for the wire resistance.
I do hope to see good, cheap, powerful motors be a thing that was more available to random third parties to swap into their old ICE vehicles. Right now the best options seem to be to use something like a Netgain Hyper9, or scavange a drive unit out of something like a Leaf or Bolt or Tesla.
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