Nickel Metal Hydride vs. Lithium Ion: Toyota has NiMH

Nickel Metal Hydride vs. Lithium Ion: Toyota has NiMH

Toyota just won Car of the Year in Aus with new RAV4 Hybrid.

It makes sense for our remote communities which want some electrification, but, it has NiMH battery!
What is with hat?
Why? Isnt that a dinosaur?
What are its pros and cons?

Ross1 | 06. desember 2019

that :)

Ross1 | 07. desember 2019

No responses so far: unusual: does no one really understand this subject?
I CAN read, so will log an article here, but I thought that with all the Prius owners turning to M3, there might have been some real world experience.
While rivals including Tesla Motors and Nissan Motor Co began adopting lithium-ion battery technology nearly a decade ago, Toyota has largely held back due to concerns over cost, size and safety.

Lithium-ion batteries can be unstable and have been blamed for incendiary Samsung smartphones and smoking Dreamliner airplanes.

Having Toyota endorse lithium-ion will be a fillip for the developing technology, and gives the automaker the option to produce for an all-electric passenger car market which it has avoided, preferring to put its heft behind hydrogen fuel-cell vehicles (FCVs).

Toyota says its Prius Prime, a soon-to-be-launched plug-in electric version of the world’s top-selling gasoline hybrid, will use lithium-ion batteries, with enough energy to make the car go around 60 kms (37.3 miles) when fully charged before the gasoline engine kicks in. Because of different methodology in measuring a car’s electric mode range, the Prime’s 60 km range will be listed in the United States as around 25 miles (40.2 kms).


Many lithium-ion car batteries use a chemical combination of nickel, cobalt and manganese. These store more energy, take a shorter time to charge, and are considered safer than other Li-ion technologies.

But they can still overheat and catch fire if not properly designed, manufactured and controlled.

“It’s a tall order to develop a lithium-ion car battery which can perform reliably and safely for 10 years, or over hundreds of thousands of kilometers,” said Koji Toyoshima, the chief engineer for the Prius.

“We have double braced and triple braced our battery pack to make sure they’re fail-safe ... It’s all about safety, safety, safety,” he told Reuters.


Toyota has mainly used the more mature nickel-metal hydride batteries to power the motor in the conventional Prius, widely regarded as the forefather of the ‘green’ car, though it did use some lithium-ion batteries from 2009 in its first plug-in hybrid Prius, around the time the first all-electric cars powered by lithium-ion batteries - such as the Tesla Roadster and Nissan Leaf - came on to the mass market.

Toyota’s confidence in its battery’s safety and stability comes from improved control technology that precisely monitors the temperature and condition of each of the 95 cells in its new battery pack.

“Our control system can identify even slight signs of a potential short-circuit in individual cells, and will either prevent it from spreading or shut down the entire battery,” said Hiroaki Takeuchi, a senior Toyota engineer involved in the development.

Working with battery supplier Panasonic Corp - which also produces Li-ion batteries for Tesla - Toyota has also improved the precision in battery cell assembly, ensuring battery chemistry is free of impurities.

The introduction of even microscopic metal particles or other impurities can trigger a short-circuit, overheating and potential explosion.

“The environment where our lithium-ion batteries are produced is not quite like the clean rooms where semiconductors are made, but very close,” Takeuchi said.
A detail is seen on a Toyota Prius Prime during the media preview of the 2016 New York International Auto Show in Manhattan, New York March 23, 2016. REUTERS/Brendan McDermid/File Photo

Battery experts say increasingly sophisticated systems that can track individual cell conditions are becoming closely-held trade secrets.

“State of charge management, safety management and algorithm development is becoming one of the higher tiers of proprietary internal development,” said Eric Rask, principal research engineer at Argonne National Laboratory, a U.S. Department of Energy facility outside Chicago.

“It’s very internal, very strategic, and companies are seeing management algorithms as a competitive advantage.”

Toyota has also been able to shrink the size of each cell, for example, closing the distance between the anode and cathode, where active ions travel when charging and discharging.

This has doubled battery capacity to around 8.8 kilowatt hours, while only increasing the battery pack size by around two-thirds and its weight by a half.


Battery experts say lithium-ion battery cell prices have fallen by about 60 percent in five years to around $145 per kilowatt hour as larger-scale production has made them cheaper to make.

Falling battery prices have enabled Toyota to develop its more compact, efficient battery, while also adding more sophisticated controls into its battery pack, Toyoshima said. Toyota declined to say more on its costs.

While Toyota sees FCVs as the ultimate ‘green’ car, the United States and China are encouraging automakers to make more all-electric battery cars as they push alternative energy strategies.

“Developing lithium-ion batteries for both hybrids and plug-ins will enable us to also produce all-electric cars in the future,” said Toyoshima said. “It makes sense to have a range of batteries to suit different powertrains.”

kevin_rf | 07. desember 2019

I will say, the nickel metal hydride pack in my '05 Prius lasted about 240,000 miles before it was replaced with a refurbished unit. Can't fault Toyota for sticking with the more proven technologies.

Btw. The much smaller '05 Prius pack, incase you have not seen one before.

inconel | 07. desember 2019

Toyota claims NiMH is better for colder climates I think? But I believe it's really just because they are behind. For their upcoming PHEV cars (Prius and RAV4) where they need higher battery density (more battery capacity in the same space) they are finally going to use Li-ion.

Bighorn | 07. desember 2019

Most of this side of the world was asleep when you posted.

andy.connor.e | 07. desember 2019

Hybrid doesnt need advance battery tech. It needs the battery to run when the engine is not, which is at very low speeds, low accelerator power. Toyota has always used Ni-MH, and using lithium batteries in their hybrids would make them even more expensive, which they already are very expensive. A hybrid Camry is very close to the price of the M3 SR+. Brand new that is.

Magic 8 Ball | 07. desember 2019

Toyota is pouring money into the H2 sinkhole. They should just get if over with and rename the company to Hindenburg Titanic.

FISHEV | 07. desember 2019

"No responses so far: unusual: does no one really understand this subject?"

Best battery info is here. | 07. desember 2019

Toyota has spent 10+years using NiMH. It's common for legacy automakers to stay with what has worked in the past. Why look at new technologies when you can sell old crap with marketing? It's one reason why legacy automakers have so few EVs worth buying today.

I'm not aware of a single EV sold today that uses NiMH. It's really a dead technology for EVs.

kevin_rf | 07. desember 2019

More like 20+ Years. The Prius came out in Japan in 1997 as a reaction to a similar "super car" program started by the Bush Sr administration to keep American automakers competitive. For two billion tax dollars, they only produced concept cars. Thirty years later, American automakers are just now getting religion.

texxx | 07. desember 2019

I bought my first Prius in 2004. After four years of driving it was clear to me they had produced an economical, reliable, inexpensive and "green" vehicle that had a substantial technological lead on other hybrids. Another four years went by and I was still waiting for the second act. Where was the All Electric Prius?? Toyota kept saying "Just wait - when batteries get good enough we'll release one." And I waited and waited and waited, watching then burn mountains of cash on Hydrogen - the "next big thing" - when the obvious path was right in front of them. To this day I have mixed emotions about Toyota. The Prius was a real game-changer, but their unwillingness to capitalize on an incredibly loyal customer base who would have gladly followed them into All Electric still baffles me. What's the number one car traded for a Tesla? You got it, a Prius. Had Toyota done the right thing every one of those sales could have been theirs, and to see them still in denial, still milking technology 20 years old, well, it's really sad. I have to believe there are engineers at Toyota livid about the path management chose to take, never having the chance to follow up on the massive success of the Prius.

How can a company with enough smarts to produce the Prius get so dumb in just 15 years?

Bighorn | 07. desember 2019

Our Prius had well over 200k miles and the range kept dropping. Who knows if the battery was helping at that point or not or whether I was driving a battery-laden ICE?

texxx | 07. desember 2019


My first Prius was still doing great at 145K when it got totaled by someone running a red light. My second one (a 2010 now driven by my daughter) has 120K on it and seems to be holding up. Still gets between 43-53 mpg, depending on weather and city/highway driving split - about what I was getting when I bought it.

rxlawdude | 07. desember 2019

The 2012+ Plug In Priuses have Lithium Ion batteries.

Earl and Nagin ... | 07. desember 2019

NiMH isn't too bad. My 2nd EV, a Gen2 EV1, had NiMH batteries. It was a big improvement over the old PbA (lead acid) batteries of the Gen1 EV1.
The biggest problem with the NiMH was the 'memory effect'. if you didn't discharge it all the way before recharging, it would lose capacity. Full charge-discharge cycles would restore some of the capacity, however, over time, partial discharge/charge cycles eventually kill a NiMH battery.
For an EV, this is not good since one really doesn't want to have to run down all the way before one can charge again. For long trips this isn't such a problem, however, for day to day, it just doesn't work.
I had a colleague with an EV1 who lived only about 2 miles from work. His battery died quickly because he'd have to charge for weekend errands even though the battery was only partly discharged from the week's driving.
Li-ion is definitely the better choice.
The other problem with NiMH is that its owners won't permit it for use in cars if it provides 100% of the car's power. With a gimped-out hybrid that's ok but it forces there to be another power source, preferably (from their perspective) fossil fuel. | 07. desember 2019

@Earl and Nagin - Cool that you owned an EV1! I've only ever met one other that actually owned one!

Loved Jay Leno's garage episode on the guy (Martin Scorcese?), that never turned in his EV1 when most were crushed by GM.

kevin_rf | 07. desember 2019

Bighorn, I watched the mpg on my '05 slowly drop into the low 40's until the battery died at 340,000 miles. Replaced the battery with a refurbished one and my mpg was suddenly back up to 48ish. Made a world of difference. Still going strong as the kiddo is now using it to go to and from school each day. Now somewhere North of 400,000 miles. Will probably have to replace it come summer.

With the exception of WV dirt roads, almost all it's miles where at highway speeds, so it never really got more than 48/49 mpg. Same as the '02 Prius.

M-A-B-MCMLXXX | 07. desember 2019

“ According to Prius chief engineer Shoichi Kaneko, in an interview this past week at the LA Auto Show, most of Toyota’s current hybrid lineup are capable of easily trading off between the two battery types for one chief reason: flexibility. In being compatible with either one, the company can more smoothly react at a factory or vehicle level to supply shortages or price pinches—for raw materials like lithium or nickel, for instance.”


Bighorn | 07. desember 2019

Ours was going strong otherwise until a pickup short stopped in front of my wife.

Earl and Nagin ... | 07. desember 2019

I never actually OWNED one. They were lease only except for Coppola (not Scorcese) who got his because of a clerical error by GM.
They were great cars. zippy, roomy (for 2), decent range (120 miles/charge), fun. It definitely ruined me for life. Fortunately, Tesla came along. | 07. desember 2019

@Earl and Nagin - You're right - My friend had to turn his in when the lease was up. I think he ended up making his own EV after that (he's an engineer).

Must have been misery to have to wait years after your first EV for another!

FISHEV | 07. desember 2019

Manufacturers respond to market demand and its just not there for PHEV's.

It's gets to the numbers on climate change. In US 67% of Americans are only willing to make small sacrifice for climate change. Subsidies are gone for GM and Tesla. US sales of PHEV's in 2019 will be flat or a bit less than last year, same for world market, down about 2% from last year, mostly due to China cutting subsidies for EV's.

Car makers look at the market demand and see a small 5% market demand for PHEV's and build accordingly. EU and China are requiring it which is why most of the new EV tech and vehicles from EU and China.

If you want to cut your global warming emissions, a Prius is an excellent choice.

Prius is a great choice for someone wanting to cut emissions
Prius AWD 216 grams per mile
Model 3 AWD 140 grams per mile.
US Average car 410
Prius 47% reduction
Model 3 66% reduction.

Njbrw549 | 07. desember 2019

We owned a 2003 Rav 4 ev with the nimh batteries for nine years. The pack was refurbished when we got it. The nimh is heavier than the lithium and it had a range of about 100 miles, 25kw pack. Chevrpn ended up with the patents in 2001 and forbid Toyota from continuing production because Panasonic had modified the battery to improve longevity.
Ther was a clause in the contract forbiding modifications. The battery pack was air-cooled but it needed better temperature control. Too much heat was bad. Many owners put over 100,000 miles on their packs. It was best to drive them every day for commuting. We used ours around town with no problems. It had lost around 5-10 % range after 9 years.

Earl and Nagin ... | 07. desember 2019

I just inherited my late grandmother's Buick and used it until we got our Tesla Roadster. I certainly could not see buying an ICE car, especially not from those who had crushed all of the EVs.
When we ordered our Tesla Roadster, we put a license plate frame on saying "waiting for my Tesla" :-)
Back to NiMH:
I remember that someone from GM started selling the old NiMH batteries as scrap material from their Yuma, AZ proving grounds where the EV1s were being destroyed. The EV community found out and started buying them like crazy --- until GM executives found out and shut down their sale.

M-A-B-MCMLXXX | 07. desember 2019

“it had a range of about 100 miles, 25kw pack”

That’s great efficiency. The 18kWh pack in my Volt rarely got me 50 miles (half of which was typically freeway).

Zsar | 07. desember 2019

The regular in this forum has to have an insult on anything

SalisburySam | 08. desember 2019

Datapoint: the NiMH battery in my wine bottle opener usually dies after 18 months. Just sayin’.

jimglas | 08. desember 2019

wine bottle opener?
I call mine a corkscrew

Earl and Nagin ... | 08. desember 2019

While the ridiculous Prius plug is barely relevant to this thread; I'll try to bring things back on track:
The Prius, while better than pure ICE, offers no path to sustainability or a useful carbon footprint. BEVs or 'reasonable' PHEVs do.
The Prius was launched by Toyota in fear that GM was serious about EVs because of the EV1. It offered a viable, economical, and politically palatable 'alternative' to BEVs and ICE within the restrictions placed by Chevron-Texaco on the NiMH battery.
Naive consumers believed that the Prius was helping the planet and flocked away from the path to sustainability to this seductive distraction, much to Toyota's delight. Luckily, for all of us, Nissan's Ghosn and Tesla, recognizing the power and freedom that Li-ion gave us, ignored the decoys and continued on the path to sustainability.
I also want to recognize Greg Hanssen and the late Pete Nortman of Energy Conversion Systems (energyCS) for engineering a hack to the Prius, enabling it to become Prius+ PHEV through introduction of a large Li-ion battery to a stock Prius ( Further, I'll recognize Felix Kramer of Calcars for stealing Peter's technology and giving it away for free, essentially bankrupting Energy CS, but also helping to let the genie out of the bottle that we don't need gasoline. | 08. desember 2019

MAB1980 @njbrw “it had a range of about 100 miles, 25kw pack”... "That’s great efficiency. The 18kWh pack in my Volt rarely got me 50 miles"

I'm sure Earl can say more, but from memory - the EV1 had a fantastic CD of .19 and only room for 2 people. The tires were super low rolling resistance, which I suspect didn't do much for handling. Back then most cars other than sports cars had poor handling, so it may not have stood out as different. I also expect the EV1 didn't have airbags or other standard safety systems in any car made today - which adds weight and bulk.

Anyway, the EV1 was a moonshot type program that was way ahead of its time. Seems GM really didn't want it to succeed despite some great engeeinring work to make it a reality.

Earl and Nagin ... | 08. desember 2019

Why so much hate for the wonderful EV1? You've been reading too much propaganda. ,-)
Of course it had airbags!! It was fully FMVSS homologated. Read "The Car that Could" by Michael Schnayerson.
Its handling wasn't perfect but with that low, centered mass it wasn't bad. Front Wheel Drive with lots of torque provided a lot of torque steer and the rear wheels closer together than the front provided a slightly strange twisting moment when turning sharply. I wouldn't recommend it for autocross as the LRR wheels would probably slip off.
On the straight line, however, it got people's attention though and was a pleasure to drive.
It is still IMHO, the best commuter car ever.

FISHEV | 08. desember 2019

"The Prius was launched by Toyota in fear that GM was serious about EVs because of the EV1. It offered a viable, economical, and politically palatable 'alternative' to BEVs and ICE within the restrictions placed by Chevron-Texaco on the NiMH battery."

Not likely as both EV1 and Prius came out within a year of each other after many years of development and Prius was built for Japanese market not US market. Prius did ship out of Japan until 2000, four years later.

"While the ridiculous Prius plug is barely relevant to this thread;"

Thread is about NIMH and Lion batteries both of which Prius uses so Prius would be the MOST relevant car in that discussion as you can have direct comparison in the same car.

M-A-B-MCMLXXX | 08. desember 2019

@Earl and Nagin
“ Luckily, for all of us, Nissan's Ghosn and Tesla, recognizing the power and freedom that Li-ion gave us, ignored the decoys and continued on the path to sustainability.”

I don’t think lithium or cobalt fit any definition of sustainable. Making batteries, which don’t last forever, depletes the research.

M-A-B-MCMLXXX | 08. desember 2019

Research = resource

Earl and Nagin ... | 08. desember 2019

lithium and cobalt are recyclable (Lithium is currently so cheap and plentiful that nobody bothers to recycle it today). Same goes with NiMH materials.
Gasoline in a Prius is burned and the energy in those free hydrogen and carbon molecules are lost forever. The residual is left forever with various impacts to the planet.
There's no comparison.

Bighorn | 08. desember 2019

Lithium is plentiful and cobalt is being engineered out of the battery.

M-A-B-MCMLXXX | 08. desember 2019

It may be plentiful, but that is independent of sustainability. If you have to continually go get more of something which in practical terms is a fixed quantity, it is not sustainable. Recycling can change the calculus, but currently lithium is being mined in mass quantities in South America.

To be clear I’m not advocating against batteries or in favor of fossil fuels, just the characterization.

Sarah R | 08. desember 2019


Size, weight, and power, plus cost.

Lithium batteries win on all counts.

Ross1 | 08. desember 2019

So, thanks for all the input.
Would anyone actually reject purchasing a RAV4 IF NOTHING ELSE fitted the bill, just because of NiMH in the new RAV4?
Like, is NiMH a deal breaker for anyone? | 08. desember 2019

@Earl and Nagi - Sorry if I came across as hating the EV1 - GM is another matter as to how they handled the EV1 demise. EV1 was ground-braking and I have a huge amount of respect for the engineering and those that got those early EVs. I didn't know about the airbags - the EV1 was so long ago, I made a bad assumption!

@Ross1 - Nothing wrong with NiMH in my mind. It just has a smaller volume density over Lithium-ion, so it takes up more space and weight for the same power as a same-sized Lithium-ion battery pack. It really comes down to the range. If it has enough range for your, great - go for it.

FISHEV | 08. desember 2019

"Like, is NiMH a deal breaker for anyone?"

No and never has been. It's kind of phony issue. If the MiMH works in the vehicle design it works.

andy.connor.e | 08. desember 2019

Ni-MH is a tough call because it just hasnt really been done in anything but hybrids. If someone can make it work, then it works you know? I'd be hard pressed to believe that Lithium is the only way to go for EVs, but someone has to do it and make it work.

M-A-B-MCMLXXX | 08. desember 2019

@andy - the second gen EV1 used NiMH. 1G was lead acid.

neurocutie | 08. desember 2019

NiMH would be a deal breaker for me... don't have much experience with the Prius but... I know NiMH vs Li for laptops and phones...NiMH is horrible compared with Li. Rapid loss of capacity and easy development of whiskers, shorting out the cells. I still have 25year old Li batteries working fine in laptops. Not possible with NiMH, dead or nearly so in a year -- nevermind that never had more than 1/2 the capacity of comparable Li cells to begin with.

kevin_rf | 08. desember 2019

Earl, the Japanese hybrids where just as much a reaction to the US government sponsored hybrid power train program for the big three US auto makers as it was to GM's Ev1.

Specifically the "Partnership for a New Generation of Vehicles" program started under the Clinton admin in 1993 (for some reason I had always thought it was Bush Sr., Old brain cells). Sadly, not unlike GM who actually built Ev1's, they only produced concept cars. Toyota and Honda actually brought hybrids to market. They feared the big three's concept cars would be more than vapor.

This is an often over looked part of the history, since everyone likes to focus on Ev1 side of the story. This story has more than one side.

Btw. An over simplified description of the program:

Bighorn | 08. desember 2019

I don’t think NiMH will be part of a million mile battery.

Tronguy | 08. desember 2019

Minor comment about Priuses, since I own a 2010 model.
Actual charge/discharge max/min levels are, if memory serves, something like 60 or 70% at full charge, something like 30 or 40% at min; so the battery specifically is Not Allowed to go outside of those ranges. This results in _much_ better longevity, and there are Priuses out there with 200k on the battery without too much trouble. Cell phone/Laptop NIMH really do get up to 100% and down to 0% and, as a result, charge/discharge cycles kill those batteries.

kevin_rf | 08. desember 2019

Put 340,000 miles on the '05 prius before the battery lit the car up like a Christmas tree. 200,000 miles is nothing for a Prius hybrid battery.

Different tech, but the longlivity of the Prius battery is what convinced me it was worth gambling a Tesla battery will last at least 200,000 miles and buy my Model 3.

Bighorn | 08. desember 2019

Our 200,000+ mile Prius was our gateway car as well, but to be fair, most of those miles are motivated by gasoline.

NKYTA | 08. desember 2019

"Tesla uses Panasonic's "NCR18650B" s (, which has a capacity of 3250 mAh and operates at around 4.2 V.
According to battery university "A 2Ah 18650 Li-ion cell has 0.6 grams of lithium content." ( So, for Tesla's 3250 mAh batteries, the lithium content would be (0.6/2)*3.250 = 0.975 g Li.
Now, with an operating voltage of 4.2V, the lithium content would be:
0.975/(3.250*4.2) = 0.0714 g/Wh = 0.0714 kg/kWh.
This is for Tesla. But Chevy Volt for instance uses pouch cells, which can have a different lithium content. So, this might be the reason why you see this variation in lithium content. It depends on the model, manufacturer and also cell geometry."