I’ve never seen an ICE car need two engines to drive all four wheels. Why do EVs need 2 motors? Wouldn’t a transmission be cheaper than another motor?
No, a transmission would cost more and the packaging issues would be way worse.
Engines are complex large expensive components so putting to of them in a car would be about the worst thing ever. Electric motors are small simple and cheap. You can hold a 500hp electric motor in your hands and all you need to make it run is plug in a wire and maybe some low pressure cooling pipes. Some EVs have 3 or even 4 of them and there is little downsides to doing this. To make the car AWD you would have to at least have a tunnel and jump inside the car for a drive shaft which is terrible.
In addition to the 8 million good reasons the others gave you, I’ll add you avoid all the typical AWD tire nonsense of replacing all 4 at a time, or ensuring the diameter of each tire is within a few 32nds of an inch of each other (I’m looking at you Subaru!)
EV motors are relatively cheap and crazy efficient. Two separate motors is the better way to do this. (Or, honestly, if it wasn’t, why do you think hundreds or thousands of automotive engineers all chose this solution rather than just mimicking the way it’s done on ICE cars?)
LOL. Not close. Go watch some YouTube videos on modern EV tech. They explain the why better than most of us.
Driveshafts, differentials, and transfer cases have left the chat.
Electric motors are crazy cheap compared to the rest of the car.
And making 2/4 small ones is cheaper than making 1 really big one plus all the transmissions and drive axles needed to move power around the vehicle.
Two primary reasons would be skateboard design of BEV’s and lack of transmission tunnel. Second motor eliminates those obstacles which would require major redesigns.
Not so much that EVs need two motors but that it’s only practical for ICE vehicles to have one. This ICE vehicles need drive shafts, transfer cases, etc.
Having an independent motor per axle is an advantage for a few reasons. It’s not that electric can’t do it the way that ice does it with driveshafts and differentials and all that, it’s the opposite. The superior solution of independent motors isn’t really an option for an ice vehicle.
Transmissions are complex mechanical wonders. Electric motors are cheap simple things. Some pilot implementations of EV had one engine per wheel.
Likely cheaper doing it with two motors vs. one motor and a transmission system to all four wheels. More weight, more friction losses, more stuff to go wrong and less control vs. two motor. Only plus would be larger motors are more efficient, maybe 5% between 2 x 100 and 1 x 200 motor?
Could Subaru put a 200 HP electric motor in an Outback and run the wheels on the existing transmission?
Cost and opportunity. A transmission is hundreds to thousands of parts and requires a whole assembly line just for it. Motors are required no matter what and they’re simple to build compared to a transmission. They can be controlled via software, which is more reliable and cheaper than making a mechanical link with all real estate, personnel, energy, and resources required to make such systems.
I’m not sure the driveshaft and extra differentials would really be that much cheaper than a second motor. Would also require a tunnel which would mean a smaller space for the battery.
Most people that do EV conversions use transmissions & transfer cases if they want AWD/4wd but it adds a lot of extra moving pieces.
Factory EVs using 2 motors gets more power as others stated, while allowing computer programming to decide when to shut off a motor, with generally less weight overall.
It’s not that they couldn’t do it all with a single motor but it’s more efficient & more powerful with multiple motors, some factory EVs use 3-4 motors, and the Mustang Mach-e 1400 prototype racer/gymkhana vehicle has 7 electric motors.
Why do EVs need 2 motors? Wouldn’t a transmission be cheaper than another motor?
The EVs don’t need 2 motors for AWD, but as opposed to what you say - a second motor is lighter, cheaper, simpler and much more efficient than adding a long shaft, transfer case and two extra differentials. On top of all that you also get the performance benefits of ability to independently govern the amount of power going to each axle.