# NiMH Batteries



## dowab (Nov 29, 2010)

When Does Chevron patent expire on the NiMH Batteries?


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## notailpipe (May 25, 2010)

According to Wikipedia, the original patent was granted in 1982 and has changed ownership many times since then. Patents expire in 20 years in the U.S., so the fact we still don't see these (actually, doesn't the Prius and other hybrids use NiMH battery packs?) makes me think they made a slight chemistry change and repatented, though I can't find much on that.

I've often considered getting a battery pack from the Prius, I've seen them eBay. I haven't thought about this idea much though, and I'm sure people have already thought about that (and probably posted about it too). Try searching around here and see what you find.


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## dowab (Nov 29, 2010)

Chevron sued Toyota for using the NiMH batteries for the Electric RAV4 but allowed them to use them for the Prius.


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## MN Driver (Sep 29, 2009)

They sued them for using the large format prismatic NiMh cells. The small NiMh cells have always avoided the patent. The 6.5Ah prismatic NiMh cells that Toyota is using on their Prius, and all of their other Toyota and Lexus hybrids was done with a contractual agreement between Panasonic(the maker of those cells) and Toyota. This is why they aren't on other hybrids such as the Honda and Ford hybrids. Honda is using 6.5Ah Panasonic cylindrical NiMh cells and Ford is using 5.5Ah NiMh cylindrical cells(not sure who manufacturers for Ford), although Ford might have something different on their Fusion but I know the Ford Escape hybrid is 250 cylindrical cells in series.

Now we have OEMs GM, Ford, and Hyundai/Kia going for LG Chem as their manufacturer of Lithium Manganese Spinel cells. GM spent a long time testing different manufacturers cells too. I think we are better off with lithium, it's getting much cheaper as time goes on and NiMh is actually more expensive. Cycle life seems to have gotten much better, the internal resistance is much better with lithium(except maybe against the cheapest LiFePO4), power and energy density are much better and I'm not sure if NiMh could compete. As far as an OEM standpoint, I doubt anyone would go for it anymore and so there really isn't a market. I think SAFT has been producing some large format NiCd and NiMh still but it's expensive and I don't think it's easy to get. There is a car(probably a few) on EV Album using them.


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## Duncan (Dec 8, 2008)

Hi Notailpipe

If they _made a slight chemistry change and repatented _
the new patent would only apply to the new chemistry and the old chemistry would then be public domain for anybody to use.

If nobody has taken it up that means either;
It wasn't that good after all
It has slipped under the radar and nobody has noticed it
Lithium has been found to be better

Off topic - still havn't found Colorado - are you sure its somewhere here in Godzone?


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## rmay635703 (Oct 23, 2008)

Yes NIMH has been around a long time but only the revised AKA under current patent NiMH are even worth bothering with as the others tended to die and wear out, we would have to find out what year Ovonics actually improved them to know when the patent dies, but i have a feeling it was early to mid 90's.

Cheers
Ryan


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## Coley (Jul 26, 2007)

Quote: 
"If they made a slight chemistry change and repatented 
the new patent would only apply to the new chemistry and the old chemistry would then be public domain for anybody to use."

Not sure the old chemistry wouldn't still be covered under it's original patent.

Changing something and repatenting doesn't remove the first patent.


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## notailpipe (May 25, 2010)

Duncan said:


> Hi Notailpipe
> 
> Off topic - still havn't found Colorado - are you sure its somewhere here in Godzone?


Hi Duncan. You're not gonna get me to change my location, haha.  I've heard of you kiwis, how come you haven't heard of beautiful Colorado? Some of the most breathtaking sights in the U.S. (<-- there's a hint for you where to start looking)

... back to topic. Actually, I know with drug patents when the patent expires they can usually get the mirror-image isomer patented, at which case the old one becomes a generic and the new one often is souped up with marketing, not necessarily better. I think when they repatented Li-Ions, they had meanwhile come up with advances in battery terminal metallurgy, for example, that you wouldn't _want_ to use the old one, patents or not, cause it's so much better with the other ones. So maybe the original Li-Ions are teh suck relative to other things out there now.


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## Duncan (Dec 8, 2008)

Hi Coley

_Not sure the old chemistry wouldn't still be covered under it's original patent.

Changing something and repatenting doesn't remove the first patent._

It would still be covered until the patent expired - 20 years - then its public domain


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## rmay635703 (Oct 23, 2008)

Before Ovonics the NiMH chemestry was all but unusable, his process changes were what made the battery and I believe his method of building the NiMH is what is patented.

Cheers
Ryan


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## Duncan (Dec 8, 2008)

Hi Notailpipe,

I lived in the US for four years - based in Indiana, we did get the train to Williams Arizona and the Grand Canyon one year - very impressive
But I think thats the closest we managed to Colorado
Bloody place is just tooooo big!

The canyon and meteor crater were impressive though, 

Also visited the Navajo reservation - I have never seen such a useless piece of land - wasn't even a good desert!


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## MN Driver (Sep 29, 2009)

Old patent or not. It looks like SAFT makes a 95Ah battery that is plenty capable and so it might just not be an issue anymore. It could be that people just aren't using it. Sure SAFT stuff might not be available to consumers, but neither was Ovonics.
http://www.saftbatteries.com/doc/Do...0810.8bbe3fae-ad43-4abd-8990-978c65b21519.pdf
http://www.saftbatteries.com/Technologies_Nickel_NiMH_329/Language/en-US/Default.aspx


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## Guest (Dec 3, 2010)

If its not available to us then it might as well not exist. Sucks but that is the truth of the matter. Saft is also very expensive. I'd bet that those NiMH batteries are more than lithiums. So if thats the case the only reason to buy them is that they have a proven track record of long life. Not so good in hot climates.


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## rmay635703 (Oct 23, 2008)

gottdi said:


> If its not available to us then it might as well not exist. Sucks but that is the truth of the matter. Saft is also very expensive. I'd bet that those NiMH batteries are more than lithiums. So if thats the case the only reason to buy them is that they have a proven track record of long life. Not so good in hot climates.


They cost more than NIFe per amphour if that gives any indication.


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