Rotary position encoders are probably the most sensitive piece of an EV. It lets the drive electronics know what angle the rotor is at, so that it can apply the correct field to produce maximum torque. Without it, the motor cannot produce much torque at all. If the motor-encoder coupling slips by one degree, or if the electrical shielding is sub-par, it would force the EV into an extremely low power limp mode, if not disable it entirely.

I would guess that encoder issues are probably the second most common EV drivetrain trouble, the first being battery problems. If one of thousands of temperature, current or voltage sensors in the battery is dodgy, it probably also would put the vehicle into limp mode. (Yes, thousands of single-point failure possibilities. That should make any reliability engineer shudder. An 800V battery needs 200 (parallel groups of) cells in series, the voltage and temperature of each needs to be individually monitored. If one goes above 4.2V or below 2V then it is a safety hazard. So voltage sensors are often doubled up for safety, and series cell strings are often doubled up for reliability)

Some technical information to get rid of misconceptions:

1) Encoders are not used for rotor position (for exactly the reasons you mention : slipping. The three phase motor has a PWM drive mechanism using half bridge topology. A hardware block monitors the current in each winding. The hardware can predict, based on the currents, when the magnetic field will cross a pole. For a very short time (called the commutation window) the PCM drive to the winding is stopped by tristating the H-bridge. A voltage comparator checks when the polarity of the back-emf changes. At this eact point the rotor has passed the winding and commutation in the H-bridge resumes.

This is nothing new. It has been done in harddisks for 20 years. It's called a torque optimiser. No need for magnet sensors, magnetic couplings.

It used to be you needed access to the center tap of the motor but there is a solution to create an artificial center tap using a resistive bridge and some sample and hold amplifiers.

2: There is no thousands of sensors in a battery pack. i can't speak for all batteries but the ones i know of have only a few tens. the heat gradient over short distance is not large due to the thermal conductivity. Also the cell topology not a parallel lump of strings. you would lose the stirng if one cells goes out or if the fuse blows. They are a single string- of parallel cells. more like a heavy chain. each cell has its own fuse in the form of a bond wire. if a cell gets damaged the fuse will pop and the cells isolates itself from the parallel bank. In practice they use banks and chains made from banks. if you make strings of individual cells you would lose the entire string. if a single cell goes out in a bank the rest of the bank still works and does not interrupt the string so you don't lose the string.

The battery management system can sense the loss of cells in a bank and instructs the balancer circuitry to take this into account.

No, having worked for a manufacturer of BMSs, I can tell you, each supercell (a bunch of cells in parallel, producing 2-4.2V collectively) is individually monitored, twice. You can't rely on string voltage to tell you if one cell is failing. Similar for temperature. This is why E-Scooters (which are not well-regulated, unlike automotive batteries) keep exploding, whereas EVs don't explode quite so often. The only thing that you can monitor at string-level is current.

As for encoders, some (less efficient) drivetrains use Hall sensors for low-speed commutation and back-EMF for high-speed, but the more efficient designs use synchronous commutation, i.e. they rely on an encoder. They can fall back to other methods of commutation in the 'limp mode' that I mentioned.

> if you make strings of individual cells you would lose the entire string. if a single cell goes out in a bank the rest of the bank still works and does not interrupt the string so you don't lose the string.

As I said, they use multiple strings, made of parallel groups (called supercells). But if a cell within a supercell fuses, then the capacity of the supercell is lowered, so you need to monitor the (super-)cell voltage to detect this, otherwise the lower-capacity supercell will reach a dangerous voltage before the whole string does.

I'm not a reliability engineer. But I had an EE class in it in University. Yes, all those connections do reduce reliability.

My room is cold, that's what really made me shudder reading that, right?

Hardly surprising though is it. Who would have thought that newer technology, electrically far more complex, would be more unreliable to begin with than a combustion engine that's had a century to be perfected/refined reliablility wise?

My 25year old gas boiler far outlived my brother's condensing boiler than had a corroded heat-exchanger after just 3 years. Far more reliable, but an awful 65% efficiency. We need the technological progress, and the reliability will catch up.

Like most technologies, design focus has shifted towards performance and efficiency, at the expense of lifetime, with a whiff or forced obsolescence. There is no fundamental reason why a condensing boiler can't have a cast iron heat exchanger like your 25yo boiler probably has, but it would be more expensive, it would take longer to warm up (so can't be used as a combi boiler) and would be (slightly) less efficient than a heat exchanger made with the thinnest possible stainless steel to get it past its 3 year warranty.

After the 3 year design life, you need a new boiler. Bonus for the manufacturer. It's the lightbulb cartel all over again, but scaled up.

There's no way it has a 3 year design life. Something like that would have a far longer warranty. I helped my mom get her furnace/AC replaced a couple years ago, and parts like heat exchangers were warrantied for 10 years. If one corroded out after three years she would get two free replacements under that warranty!

This is often neglected --- even if EVs are never as good as ICEs, we're going to have to switch to them. ICEs will always consume a finite resource, not oil as we first thought, but "space" in the atmosphere to put the resulting CO2.

ICEs will always consume a finite resource

We could make unnatural petrol with the CO2 from the atmosphere and in doing so create a new technological carbon cycle.

Yes just like the "negative emissions" from BECCS that Drax pretends exists.

In reality, they are chopping down forests to burn, destroying ecosystems and polluting the air with far worse emissions than the dirtiest of dirty brown coal, all the while collecting "green" subsidies from the UK Taxpayer!

Add to that, these designs are created by poorly paid engineers who don't have reasons to care much about the work they do.

Engineer wage no longer buys you a nice house with a garage, large garden and two cars. I know engineers in their 40s who still do flatshare and still save for a deposit while the ladders keep going up each year.

Since every big corporation don't value their workers and customers get accustomed to poor products there is no reason for any change to happen.

If the trend goes on, we will be looking at completely different metrics of EV quality. Like you are expected to drive it X years before it explodes and tears you to pieces or this 10/10 car can do 100 journeys without a service!

People are still going to buy it because there will be no alternative. Unless someone comes up with retrofitting ICE into EV. Then we will have:

(officer) "Do you know the reason I stopped you?"

(driver) "No, sir. What seems to be the officer, problem?"

(officer) "I think I saw your car was giving up smoke and I can't smell cannabis. May I see your batteries?"

(driver) "I swear, officer, I just had a spliff. It's like my battery, I cannot drive when I am not high!"

(officer) "I really don't care about that. Again, can I see your batteries?"

(driver) (unzips trousers) "Here are my two batteries and a stick".

(officer) "Step out of a suspected ICE car now!"

(driver) (speaks to the car) "Oh Tessie, I knew this was a bad idea. What have I done!" (cries)

(officer) "I count to 5 and if you don't step out, I'll zap you with the taser!"

(officer) "1... 3... 2... *Steve!* What's after 2?"

(steve) "yhmm... Let me ask Chat GPT. Hi ChatGPT what's after two?"

(ChatGPT) "I am sorry I can't answer that. All numbers are equal. Can I help you with anything else?"

(steve) "Chat GPT says all numbers are equal. Why did you want to put them in order anyway?"

(officer) (starts crying) "This is what we used to do in my days"

(driver) (plays Charlie - Spacer Woman loud)

(officer) (starts bopping his head)

(steve) (starts crying)

(driver) (slowly drives away)

That the hybrid cars did not have more problem seeing that it has both a conventional engine and EV parts I wonder why this was.

Some hybrids (maybe all but certainly Toyota's) actually have fewer moving parts than a conventional ICE vehicle. [1]Toyota's Hybrid Synergy drive doesn't have a gearbox for instance. Instead it uses a set of planetary gears that remain meshed all the time. As a result the power train of an HSD equipped vehicle is simpler than that of a traditional ICE mechanically. The only clever bit is the ECU logic which adjusts the inputs to the power split device.

The traction battery is of course an extra not present on conventional ICE vehicles but at present they use fairly conventional technology (the older Corolla/Auris models use Li-On for instance) although later models have moved to NiMh and solid state batteries are apparently coming soon for hybrids.

But overall it's established technology with just some moderately clever programming and fewer mechanical parts. It's not surprising that hybrid vehicles like Toyota's are reliable.

[1] https://prius.fandom.com/wiki/Hybrid_Synergy_Drive_(HSD)

Personally, I am waiting for a "series hybrid" with a decent-sized battery and a compact high-speed gas turbine generator. It could be lighter than a BEV yet not suffer the range anxiety. It would double as an off-grid generator for your house.

On the other hand, it would suffer the same reliability issues of an EV, with the extra issues of a high-speed gas turbine, so not surprising that it doesn't exist yet :)

In a free ecomony, the debate over EVs vs fuel burning cars will settle itself. Some types of driving are better suited to EVs. For example; someone who lives close enough to their work that they can drive to work and home on one charge. They have all night to charge the car at home before going to work the next day. Cars that burn fuel are better suited for longer trips or when you need a car before the EV can charge. An example is the driver who just got home in his EV. He plugged in the EV then he gets a call that his mom, grandma or some other family member 150 or more miles away is in hospital and he needs to get there asap. He gets in his car that burn diesel of petrol, goes to the filling station, fills up and is on his way. If he had to rely on the EV, he might be stuck at home for hours before he could go. Maybe he's lucky enough to live near one of those fast charging places. He drives the EV there, but there are several cars in the queue ahead of him. Assuming each one needs 45 minutes to an hour to charge, he still could be stuck there waiting for hours. The people who like EVs, have a use for them and can afford them will buy them. Like any early adopters, they'll have to deal with problems that come with a new technology. As manufacturers get better at making EVs and the technology gets better, they'll appeal to more and more people. As more people buy them, more people will invest in charging stations. Also more companies that don't build better cars will leave the EV market as other makers do improve the quality of their EVs.

One problem with EVs that won't end soon will be getting the electricity to charge them. In some places there have been rolling blackouts whent the weather turns exceptionally hot or cold. It's not going to helpl the flexibility of the power grid if people keep suing to stop the construction of new power stations. All that electricity has to come from somewhere.