6 ms·

Are there many gains to be had on electric motors? I guess I sort of assumed those had seen quite a bit of optimization already.

iknowstuff 6y ago
> The engineers of Tesla motor's shocked everyone when they abandoned the versatile induction motor in Model 3 cars. They used a totally different motor called IPM-SynRM. Let's understand why the Tesla engineers made this crucial design change. https://www.youtube.com/watch?v=esUb7Zy5Oio https://www.youtube.com/watch?v=esUb7Zy5Oio
- ninjinxo 6y ago
  Hrmm, so the cost and performance is much the same, but it adds value by creating a new talking point for Tesla owners to harangue others with.
  - callmeal 6y ago
    >Hrmm, so the cost and performance is much the same, but it adds value by creating a new talking point for Tesla owners to harangue others with. I know that hating on Tesla is a thing, but don't forget the higher torque, better efficiency, lower heat generation in the stator windings. And the fact that this type of motor first showed up in the Prius and Tesla made a better version of it. Yeah they're getting away with saying they invented it Prius were touting their continuously variable transmission instead of thier motors.
    - Robotbeat 6y ago
      I'm as big of a Tesla fan as any, but I'm both continuously impressed with how ahead-of-its-time the Prius was and continuously disappointed how lack-luster Toyota has been in pure electric cars. Toyota had like a decade lead on everyone else and just.... sat on it. Only invested in hybrids and hydrogen (which was and is a dead end). Toyota could've gone all-in on pure electric cars (and better plug-in hybrids than they had at the time) a good decade ago but instead they continue to waste money on hydrogen.... Only now finally announcing pure-electric cars in the US: https://www.theverge.com/2021/2/10/22187113/toyota-electric-vehicles-us-suv-debut-hybrids https://www.theverge.com/2021/2/10/22187113/toyota-electric-... It's really sad. It's really bad for the climate that they just sat on the Prius drivetrain, which is 95% of the way to a pure electric car, for over two decades (it was released in 1997... it's 2021 right now!). Literally, people have modded (i.e. added extra battery capacity) Priuses from 2003 to be pure electric even at highway speeds with the same motor and controller. They had everything sitting right there. It's incredibly frustrating.
      - simpleguitar 6y ago
        For Toyota, it wasn't the engineering, design, nor the manufacturing that was the bottleneck. It was sourcing of the batteries. Toyota sold 100k Priuses it's first year (2005), and peaked at 237k Priuses in 2012. At that time, nobody had the capacity (nor the materials), to produce that many battery packs for full EV use. In hind sight, they could have committed fully to LiIon batteries for the future, but in early 2000s, it wasn't clear at all what technology would actually win. The contenders were, as I recall, hydrogen, rechargeable batteries, and bio-fuels. Toyota had concept vehicles for each of those, and the hybrid-electric was the practical compromise at the time. Toyota, being a large scale manufacturer, could not design a car around a critical component which were in short supply, like LiIon batteries. Tesla decided to go the rechargeable route, invested heavily in battery manufacturing, and bet on LiIon analog of Moore's Law. Since they weren't going to sell 100k vehicles any time soon, they could scale along the way. Tesla didn't deliver 200k vehicles until 2018. (On a side note, Tesla also had Elon leading it. All of his 'crazy ventures' lead to colonizing Mars. What kind of a vehicle would be most practical on Mars? Not gasoline. Not hydrogen. Yep, EV. And what internet technology is the most practical on Mars? Yep, satellite constellations. What transport technology is the most practical on Mars? Underground tunnels. And so on.) Currently, all the automakers except Tesla are scrambling to secure battery capacity. Tesla is in a very nice position right now.
        RhodoGSA 6y ago
        best currency for mars? Crypto.
        simpleguitar 6y ago
        Hahaha, didn't think of that one! DogeCoin FTW!
        minitoar 6y ago
        Haha, I wonder if there is some sort of coin protocol that could be compatible with the deep space network. That latency seems like it could really mess things up.
        6y ago
fulafel 6y ago
They are so close to 100% efficiency that the possible gains are modest.
- aaronblohowiak 6y ago
  what is the cost of the motor vs the cost of the input materials? what % of the cost of a vehicle is the cost of the electric motor? My understanding (however limited here) is that car-worthy motors are still priced at a bit of a premium to their input materials, but it doesnt really matter because overall they are still not that expensive compared to batteries.
  - elihu 6y ago
    Yeah, some motors have rare-earth permanent magnets which are expensive. Induction motors don't, they just have a weird squirrel-cage structure made of (I guess) copper. Probably the manufacturing inputs for an induction motor are cheap, but the motors are a bit inefficient. I'm currently doing a conversion that uses a Netgain Hyper9 [1]. They cost about four and a half thousand dollars (including controller) and they're pretty bulky and heavy. They're really efficient though. An OEM manufacturer I'm sure could have a motor made much more cheaply and design it to run at a much higher voltage and produce correspondingly more power. I think the Hyper9 just uses magnetized iron or something like that for the permanent magnets. No rare-earths, so it might be pretty cheap to make something like that in volume. They serve the conversion market though, so it's kind of niche product. I have no idea what Nissan spends to make something like a Leaf motor. [1] https://www.go-ev.com/motors-warp.html#HyPer_9HV https://www.go-ev.com/motors-warp.html#HyPer_9HV
- sbeller 6y ago
  Look at it the other way round: they could reduce losses from 6% to 4%, which lead further savings in needing less cooling tech.
- pappn 6y ago
  Note that the impressing 9x% efficiency rates that we hear about are peak efficiency rates. There is something to gain in widening the operating ranges of this efficiency also. See for instance https://www.researchgate.net/figure/Efficiency-maps-of-several-IPM-motors-in-EVs-HEVs-9-12-13-a-2011-Sonata-b_fig2_309687186 https://www.researchgate.net/figure/Efficiency-maps-of-sever...
dzhiurgis 6y ago
Heat scavenging is probably biggest efficiency gain you can get. Tesla was relatively late to add heat pumps, but did innovate with octovalve (which has like 8 modes of heat distribution, one of which is storing something like 2kwh of heat in battery volume itself).
Robotbeat 6y ago
Yes. A big improvement over the last few decades is rare earth magnets, which have reduced the mass, increased the power and efficiency. (Rare earth magnets in car motors can be and are recycled, FWIW.) Additionally, the power electronics have improved a lot, too, and continue improving. As others have noted, Tesla went from their induction motors (which use no rare earths) to a somewhat more efficient combination of switched reluctance and brushless DC motor using some rare earth magnets. There are also various improvements to rare earth magnets. Magnetic energy density improves somewhat. Cooling schemes improve. Even alternatives to rare earth magnets (certain phases of iron or nickel, for instance) have been and are studied. I think improvements in cooling schemes is a big part of future improvements. As well as reduction in eddy current losses through better litz wire, maybe playing with the grain structure of the conductor, etc. Longer term, there's also the possibility of superconducting motors. Although that's mostly for larger scale applications, (near-)room temperature superconductors also have been demonstrated and folks are searching for methods to allow them to work at lower pressures. So I think there's actually lot of room for improvements beyond low effort prototypes from big automakers. Tesla is doing really well with high efficiency powertrains. There's also the added dimension of integration with reduction gearing (as electric motors like to spin fast).
elihu 6y ago
There's some gain to be had in terms of efficiency, but not much. Induction motors are I think generally approaching 90%, and SRIPM-type motors are in the mid 90's. Probably the biggest gains going forward will be around improving the ratio of power output to weight, and reducing manufacturing costs (of both the motor and the controller). Maybe also increasing maximum RPM and improving durability, for whatever application where current motors aren't good enough. It might also be nice to have more standardization and modularity. In the EV conversion world, there's kind of a defacto standard of motors made specifically for conversion mostly using a B-face with a 1 1/8th inch shaft with a quarter inch key slot. That helps a lot, as you can buy a motor from one company and a transmission adapter plate and coupler from another company and have pretty good odds it'll work. There are apparently ways to get almost any motor to work with almost any transmission, but that usually requires custom fabrication. (Obviously you can also ditch the transmission and just connect the motor directly to the drive shaft or transaxle or whatever. I don't know much about that route.)

iknowstuff 6y ago

> The engineers of Tesla motor's shocked everyone when they abandoned the versatile induction motor in Model 3 cars. They used a totally different motor called IPM-SynRM. Let's understand why the Tesla engineers made this crucial design change. https://www.youtube.com/watch?v=esUb7Zy5Oio https://www.youtube.com/watch?v=esUb7Zy5Oio

ninjinxo 6y ago
Hrmm, so the cost and performance is much the same, but it adds value by creating a new talking point for Tesla owners to harangue others with.
- callmeal 6y ago
  >Hrmm, so the cost and performance is much the same, but it adds value by creating a new talking point for Tesla owners to harangue others with. I know that hating on Tesla is a thing, but don't forget the higher torque, better efficiency, lower heat generation in the stator windings. And the fact that this type of motor first showed up in the Prius and Tesla made a better version of it. Yeah they're getting away with saying they invented it Prius were touting their continuously variable transmission instead of thier motors.
  - Robotbeat 6y ago
    I'm as big of a Tesla fan as any, but I'm both continuously impressed with how ahead-of-its-time the Prius was and continuously disappointed how lack-luster Toyota has been in pure electric cars. Toyota had like a decade lead on everyone else and just.... sat on it. Only invested in hybrids and hydrogen (which was and is a dead end). Toyota could've gone all-in on pure electric cars (and better plug-in hybrids than they had at the time) a good decade ago but instead they continue to waste money on hydrogen.... Only now finally announcing pure-electric cars in the US: https://www.theverge.com/2021/2/10/22187113/toyota-electric-vehicles-us-suv-debut-hybrids https://www.theverge.com/2021/2/10/22187113/toyota-electric-... It's really sad. It's really bad for the climate that they just sat on the Prius drivetrain, which is 95% of the way to a pure electric car, for over two decades (it was released in 1997... it's 2021 right now!). Literally, people have modded (i.e. added extra battery capacity) Priuses from 2003 to be pure electric even at highway speeds with the same motor and controller. They had everything sitting right there. It's incredibly frustrating.
    - simpleguitar 6y ago
      For Toyota, it wasn't the engineering, design, nor the manufacturing that was the bottleneck. It was sourcing of the batteries. Toyota sold 100k Priuses it's first year (2005), and peaked at 237k Priuses in 2012. At that time, nobody had the capacity (nor the materials), to produce that many battery packs for full EV use. In hind sight, they could have committed fully to LiIon batteries for the future, but in early 2000s, it wasn't clear at all what technology would actually win. The contenders were, as I recall, hydrogen, rechargeable batteries, and bio-fuels. Toyota had concept vehicles for each of those, and the hybrid-electric was the practical compromise at the time. Toyota, being a large scale manufacturer, could not design a car around a critical component which were in short supply, like LiIon batteries. Tesla decided to go the rechargeable route, invested heavily in battery manufacturing, and bet on LiIon analog of Moore's Law. Since they weren't going to sell 100k vehicles any time soon, they could scale along the way. Tesla didn't deliver 200k vehicles until 2018. (On a side note, Tesla also had Elon leading it. All of his 'crazy ventures' lead to colonizing Mars. What kind of a vehicle would be most practical on Mars? Not gasoline. Not hydrogen. Yep, EV. And what internet technology is the most practical on Mars? Yep, satellite constellations. What transport technology is the most practical on Mars? Underground tunnels. And so on.) Currently, all the automakers except Tesla are scrambling to secure battery capacity. Tesla is in a very nice position right now.
      - RhodoGSA 6y ago
        best currency for mars? Crypto.
        simpleguitar 6y ago
        Hahaha, didn't think of that one! DogeCoin FTW!
        minitoar 6y ago
        Haha, I wonder if there is some sort of coin protocol that could be compatible with the deep space network. That latency seems like it could really mess things up.
      - 6y ago

fulafel 6y ago

They are so close to 100% efficiency that the possible gains are modest.

aaronblohowiak 6y ago
what is the cost of the motor vs the cost of the input materials? what % of the cost of a vehicle is the cost of the electric motor? My understanding (however limited here) is that car-worthy motors are still priced at a bit of a premium to their input materials, but it doesnt really matter because overall they are still not that expensive compared to batteries.
- elihu 6y ago
  Yeah, some motors have rare-earth permanent magnets which are expensive. Induction motors don't, they just have a weird squirrel-cage structure made of (I guess) copper. Probably the manufacturing inputs for an induction motor are cheap, but the motors are a bit inefficient. I'm currently doing a conversion that uses a Netgain Hyper9 [1]. They cost about four and a half thousand dollars (including controller) and they're pretty bulky and heavy. They're really efficient though. An OEM manufacturer I'm sure could have a motor made much more cheaply and design it to run at a much higher voltage and produce correspondingly more power. I think the Hyper9 just uses magnetized iron or something like that for the permanent magnets. No rare-earths, so it might be pretty cheap to make something like that in volume. They serve the conversion market though, so it's kind of niche product. I have no idea what Nissan spends to make something like a Leaf motor. [1] https://www.go-ev.com/motors-warp.html#HyPer_9HV https://www.go-ev.com/motors-warp.html#HyPer_9HV
sbeller 6y ago
Look at it the other way round: they could reduce losses from 6% to 4%, which lead further savings in needing less cooling tech.
pappn 6y ago
Note that the impressing 9x% efficiency rates that we hear about are peak efficiency rates. There is something to gain in widening the operating ranges of this efficiency also. See for instance https://www.researchgate.net/figure/Efficiency-maps-of-several-IPM-motors-in-EVs-HEVs-9-12-13-a-2011-Sonata-b_fig2_309687186 https://www.researchgate.net/figure/Efficiency-maps-of-sever...

dzhiurgis 6y ago

Heat scavenging is probably biggest efficiency gain you can get. Tesla was relatively late to add heat pumps, but did innovate with octovalve (which has like 8 modes of heat distribution, one of which is storing something like 2kwh of heat in battery volume itself).

Robotbeat 6y ago

Yes. A big improvement over the last few decades is rare earth magnets, which have reduced the mass, increased the power and efficiency. (Rare earth magnets in car motors can be and are recycled, FWIW.) Additionally, the power electronics have improved a lot, too, and continue improving. As others have noted, Tesla went from their induction motors (which use no rare earths) to a somewhat more efficient combination of switched reluctance and brushless DC motor using some rare earth magnets. There are also various improvements to rare earth magnets. Magnetic energy density improves somewhat. Cooling schemes improve. Even alternatives to rare earth magnets (certain phases of iron or nickel, for instance) have been and are studied. I think improvements in cooling schemes is a big part of future improvements. As well as reduction in eddy current losses through better litz wire, maybe playing with the grain structure of the conductor, etc. Longer term, there's also the possibility of superconducting motors. Although that's mostly for larger scale applications, (near-)room temperature superconductors also have been demonstrated and folks are searching for methods to allow them to work at lower pressures. So I think there's actually lot of room for improvements beyond low effort prototypes from big automakers. Tesla is doing really well with high efficiency powertrains. There's also the added dimension of integration with reduction gearing (as electric motors like to spin fast).

elihu 6y ago

There's some gain to be had in terms of efficiency, but not much. Induction motors are I think generally approaching 90%, and SRIPM-type motors are in the mid 90's. Probably the biggest gains going forward will be around improving the ratio of power output to weight, and reducing manufacturing costs (of both the motor and the controller). Maybe also increasing maximum RPM and improving durability, for whatever application where current motors aren't good enough. It might also be nice to have more standardization and modularity. In the EV conversion world, there's kind of a defacto standard of motors made specifically for conversion mostly using a B-face with a 1 1/8th inch shaft with a quarter inch key slot. That helps a lot, as you can buy a motor from one company and a transmission adapter plate and coupler from another company and have pretty good odds it'll work. There are apparently ways to get almost any motor to work with almost any transmission, but that usually requires custom fabrication. (Obviously you can also ditch the transmission and just connect the motor directly to the drive shaft or transaxle or whatever. I don't know much about that route.)