No rare earth metals in the Model S

[001sky]

Tesla does not use rare earth metals in our battery or motor.

The HN Title [1] should be changed, as it is in effect editorializing beyond the information provided, IMHO. As others have noted, there is no information to suggest the statement is generally true, beyond these two sub-system components.

[1] Currently: "No rare earth metals in the Model S"

[dnautics]

there are almost certainly rare earth metals in the speakers, for example, although the mass would be relatively cheap compared to what you would need for a motor.

Does the tesla have regenerative braking system, and I wonder if there are rare earth metals there?

[bauer]

Agreed. Quite a few high-strength steel alloys contain Vanadium as well.

[AsymetricCom]

Clearly, the editors are holders of TSLA.

[fersho311]

I wasn't sure what the implications of rare earth metals were, so I looked it up. In sort, Rare metal extraction involves substantial pollution in the mining, onsite processing, and refining phase. Mines create environmental degradation through topsoil loss, poorly controlled tailings ponds that leach into groundwater as well as lakes and rivers, roads slicing through habitat, and the use of large amounts of energy to extract and process the materials they uncover. Some rare earth metals require substantial processing, and that provides a number of opportunities for pollution at every step of the way. More here: http://www.theguardian.com/commentisfree/2011/sep/26/rare-ea...

[steven2012]

I think it's more to do with the fact that China has a monopoly on most rare earth metals, and the supply can get constrained, like they did last year against Japan.

[mchannon]

While the motors may be REE-free, I wouldn't be so sure about the rest of the vehicle.

Many models of LED's, lasers, displays, headlights, and power circuits use trace but nonetheless essential amounts of rare earths. The motors and actuators (power windows and locks, charge port and frunk poppers) and seat heater relay might also contain them.

[sologoub]

Definitely doubt it's possible to have a completely REE-free modern electric car.

The post name is definitely click-bait and should be clarified.

[hristov]

I think the point the poster is trying to get across is that there are no more rare earth metals in a Tesla model S than any other car of its class. Of course there may be some small amount of rare earth metals in the speakers or the electronics, but this is not an increase from any other car.

The issue of rare earth metals was used by some nay-sayers to incorrectly argue that the Tesla model S is more environmentally damaging than equivalent gasoline powered cars.

[jlgreco]

Why is this notable, beyond possibly price associated with them? The only issue with rare earth metals is that at various times the supply of them has been politically shaky, though I think that is currently not the case? I'm not really sure...

[dnautics]

currently not the case, as the US has spun up rare earth metal mines (molycorp, e.g.) also the environmental concerns are less (not to say they are nonexistent) when the US does it because we tend to care about the environment more than china does, especially in california.

Also don't be decieved by the term, rare earth metals aren't really all that rare. If anything their expense comes from the difficulty in extracting them selectively from their ores - because rare earths are chemically similar (has to do with the f electron shell being physically "buried" under the d and s shells) they tend to ore together, and then become tricky to separate.

[zafka]

It would be possible to build a more compact motor using NFeB magnets, but the cost outweighs the slight weight/performance gain. It is also my understanding that induction motor that Tesla uses is more efficient at regenerative braking.

[chao-]

The linked page describes this as something that "absolutely belongs up on the Model S Facts page". Is there anything particularly negative about rare earth metals aside from their potential scarcity?

Edit: fersho311 answers my question in the same minute I ask it. Thanks :)

[phy6]

The typical hipster that would complain about "rare earth" metals in a car they'll never afford doesn't care about the rare earth in their iPhone or iPad (which is one of the reasons they are made in China).

[diydsp]

Fascinating! but I would add that not only DC motors use permanent magnets, but also many synchronous motors, including stepper motors.

[dskhatri]

Yep, Permanent Magnet AC (PMAC) motors are common types of synchronous motors. They are generally more compact than induction motors for the same power output. Induction motors are generally less expensive.

An official (not forum post) article comparing the two: http://www.teslamotors.com/blog/induction-versus-dc-brushles...

DC Brushless and PMAC are interchangeable. Oh, and nowadays, you don't need sensors (hall, encoder etc). 'Sensorless' motor control is possible by sensing the back emf of the motor or reconstructing the motor current via (super inexpensive) shunt resistors on the legs of the inverter.

[baddox]

I actually wasn't aware that induction motors don't use permanent magnets. RC model aircraft is a hobby of mine, and all I knew is that the commonly-used brushless AC motors certainly use permanent magnets.

[kvprashant]

Stepper motors are small in scale, are they not? And, synchronous motors are also AC motors in steady state.

[codex]

No other electric car manufacturer can make this claim, as the rest use permanent magnets in their motors despite the higher cost. Why, I don't know.

[hristov]

Because they want to have DC motors, while Tesla uses an AC motor. There are various advantages disadvantages to both. DC motors require permanent magnets. The AC motor on the other hand has the problem that the power coming out of the battery is DC. So it has to be converted back to AC in order to be used in an AC motor.

The Tesla has a large inverter that converts the DC to AC. Most other makers choose to have a DC motor in order to remove the need for an inverter.

Some people joke that Tesla chose an AC motor, because that was the motor invented by Nicola Tesla. But the AC motor has other advantages such as its excellent torque curve. The latter ensures that the model s has no gearbox while it features amazing acceleration at all speeds.

[pkulak]

Why do you say that? I'm pretty sure every other car uses synchronous AC motors, just like Tesla. Do _any_ AC motors use permanent magnets?

[achy]

Does anyone know the relative merits of induction vs brushless with regards to regenerative braking?

[kineticfocus]

There's a good answer in the comments section... http://www.teslamotors.com/blog/induction-versus-dc-brushles... ... search for 'regenerative'

[smackfu]

This is just a forum post by Joe Random, not sure why it was posted here.

[kvprashant]

For the purpose of discussion.

[amalag]

Lithium?

[archangel_one]

Not a rare earth element.

[fancyketchup]

Li more abundant in the Earth's crust than Cu, Zn, or Ni. I don't think we're going to run out any time soon.