Japanese researchers develop EV motor not reliant on rare earth metals

July 27, 2011 by Bob Yirka, Phys.org report

Japanese researchers working out of Tokyo University of Science, have built what they describe as a motor for electric cars that does not require so-called rare earth metals; a move that could drive down the costs for such vehicles.

Rare earth metals are a set of seventeen metals that, despite their name, are not actually rare; instead they are widely dispersed in the Earth’s surface, making mining both difficult and expensive. Japan has been particularly sensitive to the use of rare earth metals in electric and hybrid creation, because the country doesn’t have a source of such materials of its own, and therefore must import it from other countries, most notably China, which some in Japan have accused of using monopolistic business practices. Thus, researchers in Japan have been hard at work trying to find either a substitute, or a way to make electric motors that don’t require the special properties of .

With the new motor, the researchers have opted for the latter and claim the new motor they’ve created has an output of 50KW and efficiency of more than 95 percent. They are calling it the “Switched Reluctance Motor” because it produces its electric charge by using the difference in magnetic resistance via rotation, when the electricity running though a coil is turned on and off, which means the motor doesn’t need a permanent magnet.

The team, led by Associate Professor Nobukazu Hoshi, showed off their new motor (which looks like a big tin box under the hood) that they say is approximately the same size as the motor used in a Toyota Prius, at the Techno-Frontier 2011 trade show in Tokyo last week.
And while the team does acknowledge that their motor is not able to produce torque equal to current EV motors, and thus is not as energy efficient, they believe further research will lead to breakthroughs that will make it more then competitive in the marketplace. There is also apparently, an issue with noise and vibration, but the team says it’s a minor problem that will be easily corrected.

Explore further: Toyota developing alternative electric motor

More information: www.youtube.com/watch?v=Cq_9EntG35w

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3.2 / 5 (5) Jul 27, 2011
most importantly .. Japs won't have to give money to the age old enemy.

Rightly so ... there is always scope to make things work better
4.3 / 5 (4) Jul 27, 2011
Necessity is the mother of invention. If they can make it work without rare earths then that is a great step forward. next step is to make batteries work without rare earths
2.9 / 5 (8) Jul 27, 2011
Hey China- you know what you can do with your rare earths?
4.5 / 5 (6) Jul 27, 2011
Vibration and wear are a problem, but noise is a problem? From what I hear, a little bit of noise is a good thing, so people can hear the car coming up.

They say that the motor is 95% efficient, but that it isn't efficient enough yet to compete with rare earth metal motors, due to torque. I feel like I'm not given enough info to fully understand what's going on here...
5 / 5 (1) Jul 27, 2011
what's the difference between this and a series wound motor?
2.3 / 5 (13) Jul 27, 2011
uhhh, iknow, "Japs" isn't the preferred nomenclature. You might want to work on that.
2.6 / 5 (5) Jul 27, 2011
uhhh, iknow, "Japs" isn't the preferred nomenclature. You might want to work on that.

True, but when you think about it, why is that offensive but calling someone a Brit isn't?
5 / 5 (2) Jul 27, 2011
And exactly which EVs use permanent-magnet (rare earth) motors?

The Tesla Roadster, Chevy Volt, and Nissan Leaf all use AC motors, which do not require magnets, nor rare earths.

Heck, even my own 30-year-old EV, a "Jet Electra Van", uses a series-wound DC motor, and no magnets.

I understand some hybrid designs have used permanent magnet motor designs. These are not EVs.
5 / 5 (2) Jul 27, 2011
...next step is to make batteries work without rare earths

Your wish has been granted. Li-Ion batteries do not contain rare earths.

In fact, none of the current EVs on the market use rare earths either, despite the headline of the article.
1 / 5 (2) Jul 27, 2011
Let's see if this actually goes into production soon or gets held up by bureaucratic red tape for the next ten years.
2.5 / 5 (11) Jul 27, 2011
Gee, imagine that. Market forces create a better, cheaper alternative.
5 / 5 (1) Jul 27, 2011
.. the prius uses a whopping 10kg of Lanthanum in its NiMH battery pack.

Xcuse me?.. That's hardly a solution when you think of millions of cars..
not rated yet Jul 27, 2011
On the subject of rare earths and batteries, the prius uses a whopping 10kg of Lanthanum in its NiMH battery pack.

NIMH batteries are the past. No current EV projects use them. And Li-Ions use no rare earths.
5 / 5 (2) Jul 27, 2011
Gee, imagine that. Market forces create a better, cheaper alternative.

First of all, the article points out that this motor design (which is not really even new!), is NOT less expensive, and NOT more efficient than existing EV motors.

In other words, a very puzzling article telling us that this brand new motor - which was really invented years ago...


will let us build EVs without rare earths - even though today's EVs already use no rare earths.
5 / 5 (1) Jul 27, 2011
As soon as I heard about the rare Earth magnet problem I immediately thought about an AC induction motor and didn't see any real problem. I think this whole thing was dramatized quite a bit.
1 / 5 (1) Jul 28, 2011
It sounds like this motor has an iron rotor that is pulled in a circle by a series of electromagnetic coils that are switched on and off one at a time to cause rotation of the rotor by magnetic attraction and is controlled by an elctronic switching circut that uses direct current from a battery and is completly different from AC induction or motors using magnets that employ magnetic fields that repel each other.
3 / 5 (2) Jul 28, 2011
In other words, a very puzzling article telling us that this brand new motor - which was really invented years ago...

Well when you compare it like that, ANY electric motor was invented a century ago by Micheal Faraday. Theory and implementation are two MAJOR distinctions.
not rated yet Jul 28, 2011
"It sounds like... " how very scientific of you ;)
5 / 5 (2) Jul 28, 2011
The technology is 30 years old. Pioneering work was done in University of Leeds and University of Nottingham. University of Glasgow has also done a lot to forward the technology. The Dyson vacuum cleaner uses a SR (switched reluctance) motor. It is notoriously noisy but there are ways to quiet it down. it uses no rare earths which makes the technology much more attractive now versus just six months ago. It can meet rare earth magnet motors but a lot of provisions need to been made to improve the efficiency.

Permanent magnet machines uses the alignment torque for movement, SR and synchronous reluctance machines employ reluctance torque to facilitate movement. The power electronic drive is also different from an induction motor drive and a PM motor drive.

Japamn has been working on this for the last few years, they have kept an eye on the rare earth market for a long time and their government has funded research in the area. The US DOE is just beginning the funding cycle fo
1 / 5 (1) Jul 31, 2011
They should just buy their motors from The USA. No reason to re-invent the wheel.
not rated yet Aug 07, 2011
they should focus on a motor running on ambient radioactivity

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