>So one would think that when EVs reach the same scale they will be significantly cheaper than ICE vehicles.
I expect that batteries are the only hangup, there's probably not that much magic left in an electric motor. Additional cost for regen brakes of course.
I agree on the amazing cheapness of it all if you stick with the common stuff. That, along with the low cost of flat panel TVs is a miracle of the modern age.
Regen braking has no physical cost associated - it's pure software/firmware. The exact same hardware that is used to power the car forwards can be used for regen braking. It can be as simple as a single negative sign in the code to cause the phase to be 180 degrees out, current to flow backwards, torque to go the other way, and the battery to be charged instead of discharged.
One day regen braking will take over hydraulic brakes, and another big cost/complexity of a car will be eliminated. The only reason that doesn't happen today is there are lots of laws and regulations requiring hydraulic brakes, and braking systems typically require more redundancy than power systems.
> Regen braking has no physical cost associated - it's pure software/firmware.
I think this is a slight exaggeration.
The way I understand regenerative braking is that you (effectively) run your AC generator in reverse of what you would in order to accelerate in the direction of motion and then take the current generated by that, rectify it to DC, and use that current to charge a battery. The energy in the system is provided by the back EMF induced in the stator by the magnetic field generated by the motor rotor. I agree that the AC generator is going to stay the same, but I think there's specialized hardware needed for the rectification and charging cycles. At the minimum, you need a more specialized battery and battery management system to make sure that you're balancing the charge across the cells in your battery.
I think you are overestimating unique requirements of typical car engines. They are usually DC powered AC engines, where the DC->AC converter (generating 3-phase AC of controlled power and frequency) can probably run backwards (AC->DC) with at most a few minimal hardware changes, if any.
If you're not overdoing regen, you probably don't need additional balancing. Even if you wanted to charge the EV by towing, you could probably use the normal charge balancing circuitry, again minimal if any HW changes. Non-wimpy batteries and cells should be fine - if they can fast-charge, they can take regen. Might have some limitations on acceptable power vs. temperature, charge state etc.
> One day regen braking will take over hydraulic brakes, and another big cost/complexity of a car will be eliminated.
I have read somewhere that the regenerative braking is much less effective when the car is going really slow, so you still need the hydraulic brakes to come to a complete stop.
True, but you can also use a tiny bit of battery power to do "reverse acceleration" to do the final stopping.
It is true that electric braking would continuously use a small amount of power to stay stopped on a slope. That wouldn't be an issue for a few hours, but you couldn't park on a hill for months without ending up with a flat battery, and then eventually the car rolling away.
Small locking pins are the answer to this, rather like the "park" on automatic gearboxes. They are very cheap, since they don't need to do any actual stopping, but merely keeping something stopped.
Is that right? I didn't know that. I'd like to see a BOM on a regen braking as compared to a simple disk brake system.
One implication to software-only brakes is that it requires that that corner is a drive wheel. If that's the case, I suppose that anti-lock is simply firmware and a sensor.
note: I do see that Teslas have master cylinders, so they apparently are hydraulic braking systems.
A bill of materials? As OP said, there is literally nothing required aside from what is required to make the car go forward. An electric motor is a generator.
Teslas have traditional braking systems in addition to the regen braking. The hydraulic brakes have nothing to do with the regen system.
I appreciate that now. Thank you to everyone for the education.
>The hydraulic brakes have nothing to do with the regen system.
I strongly suspect that they interact for antilock.
I wonder how Teslas deal with parking brakes, historically kind of an issue with disks.
It does seem to me that an entirely regenerative braking system would imply additional expense in terms of the strength of the half shafts, u-joints, transmission if any.
Parking brakes for disc brakes are usually in the center of the disc rotor (like a mini drum) with shoes. Some others like Chryslers have implemented hybrid brake cylinders
That's really astounding, I just looked at a 55 inch brand name 4k TV going for 400 bucks retail.
Guess it's the same logic as cramming more CPU, etc. into the usual couple hundred sq. mm chip. But you get more CPU for the same money and chip size, which is not as spectacular as more screen size for less money ...
> there's probably not that much magic left in an electric motor.
I believe this sentence has been said about many technologies in the past that definitely invalidated it. I'm more playing devil's advocate than trying to falsify you, likely for being burned sometimes reading or, worse, stating it, haha.
There isn't much more efficiency to be gained in the electric motor world. Motors typically get 90% of theoretical efficiency, so any improvements there will be modest.
Substantial improvements in other metrics might be had, but they probably won't massively impact EV's (weight and costs of the motor are both a small part of the total for a car)
Batteries are a huge hangup. For example, we don't know how to recycle them and they aren't good for dumps. And, used car batteries are expensive to replace and you get a lot fewer miles per charge out of older cars. Manufacturing of cars isn't great for the environment so we should want older cars to last. This model helps push people to more new cars faster.
I expect that batteries are the only hangup, there's probably not that much magic left in an electric motor. Additional cost for regen brakes of course.
I agree on the amazing cheapness of it all if you stick with the common stuff. That, along with the low cost of flat panel TVs is a miracle of the modern age.