Hacker News new | ask | show | jobs
by eastbound 541 days ago
An electric motor is dirt cheap compared to the ingenuity of an ICE. The battery is expensive because it’s a lot of mass of peculiar rare earths, but motors aren’t.
3 comments

> The battery is expensive because it’s a lot of mass of peculiar rare earths, but motors aren’t.

It's the other way about. Batteries in Chinese cars are mostly lithium iron phosphate. Not a lot of rare earths there. The motors are mostly permanent magnet motors and they definitely do have rare earths.

But anyway the name rare earths is mostly a misnomer, they aren't especially rare, less so than gold, copper, etc. They are just not conveniently located for extraction.

The batteries are expensive simply because the replacement battery market is not yet a large low risk mature market. This is in part because the batteries are lasting longer than most people, the manufacturers included, expected.

rare (in the) earth, i.e. well distributed, not lacking in quantity.
Lithium ion batteries don’t usually have rare earth minerals. Some use rare minerals like cobalt but they are moving away from those chemistries.

It is the electric motors that use rare earths but sounds like companies are moving away from that.

Not all that relevant from a maintenance perspective though. Electric motors essentially Don't Fail.
High-performance electric motors do fail all the time. They overheat, position sensors are slipping, the converters IGBT's last max 6 years.

You are talking simple engines, I'm talking high-end engines.

In the context of the motor alone, those don't fail.

The circuits driving it probably have a higher failure rate, but we've gotten so good at manufacturing electrical circuits it still seems much easier and cheaper than a mechanical engine.

I worked with high performance electrical engines. They do fail all the time. Not in cheap consumer cars though.
In theory yes, but electric motors can be very complex in much the same way that ICE engines can be. Batteries of the kind used in modern EVs are single-use and far too expensive and dangerous to service. The level of effort required to maintain an EV past 20 years will be way higher than that required to maintain an ICE car that long. Very few ICE parts have a limited shelf life, and the ones that do are either consumable or else easily substituted such as rubber seals and belts.

This analysis is really just relevant for cars that someone would want to keep well-maintained for 20+ years at significant expense. Most EVs are boring so I don't expect them to be in that category either. But if you did really get attached to one, you might have to rebuild it from scratch with totally different internals to keep it going, and it would only look like the original on the outside.