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PowerGenix Introduces NiZn Cells for HEV Market

15 May 2008

The PowerGenix 120-cell 1.2 kWh HEV pack sitting atop the larger NiMH pack in a Prius.

PowerGenix, a San Diego-based developer of high-performance, sealed rechargeable nickel-zinc (NiZn) batteries for power tools and other applications, introduced its rechargeable D cells for hybrid electric vehicles (HEVs) this week at the Advanced Automotive Battery and Ultracapacitor Conference in Tampa, Florida. (Earlier post.)

The 6.5 Ah, 1.6V NiZn D cells offer energy and power densities of 100 Wh/kg and 2,500 W/kg in their first generation, according to PowerGenix CEO Dan Squiller, with more room for improvement in subsequent iterations. NiZn packs can deliver 30% more power and increased energy density, as well as reduced size, weight and cost relative to existing Nickel Metal-Hydride (NiMH) technologies.

The company brought a Toyota Prius retrofitted with a 120-cell, ~1.2 kWh NiZn battery pack to highlight the size and weight savings of PowerGenix’s technology to the AABC event.

Early NiZn batteries (first developed in the 1920s) suffered from short cycle life due to dendrite growth leading to short circuiting, caused by the high solubility of zinc oxide—a discharge product of the zinc anode in the alkaline electrolyte. In addition to dendrite formation, zinc oxide solubility can result in shape change and densification of the anode on repeated charge/discharge cycles.

The basis of PowerGenix’s approach to making its NiZn battery commercially viable is a patented electrolyte formulation that reduces zinc solubility and prevents the dendrite shorting and shape changing problems. Further enhancement of cell capability is due to cathode and anode materials that are free of any heavy metal elements.

In addition to addressing the cycle life problems, PowerGenix’s approach allows the NiZn cells to be manufactured on existing NiMH and NiCd lines—a considerable advantage considering the on-going investment in NiMH production being made.

The NiZn battery pack is easily integrated into existing hybrid control systems—the battery’s operational state of charge range is approximately the same as that of NiMH.

With a power density that can compete with some Li-ion chemistries, the NiZn cells have none of the Li-ion thermal safety issues; with the inorganic KOH electrolyte, there is no thermal runaway. NiZn is also about half the cost of Li-on technology, according to Squiller.

Despite the ongoing advancement in Li-ion technologies, vehicle applications are just beginning (with the exception of the Li-ion stop-start system in the low-volume Toyota Vitz in Japan) in 2009. As a result, NiMH is still anticipated to have a significant automotive presence in hybrid applications for a number of years.

Squiller suggests that the automotive battery market will segment over the next few years, with the rapidly scaling Li-ion systems supplying energy storage solutions for very high energy applications (PHEVs and EVs and some upper-end full hybrids) at high consumer cost. NiMH—or, in PowerGenix’ scenario, NiZn—will continue to serve the more economical, lower-end hybrid vehicles with lower energy requirements but still demanding power requirements.

PowerGenix plans call for licensing its technology to one of the major NiMH battery manufacturers, such as Sanyo. “Better chemistry and better cell design basically is just an ante to get to the table,” said Squiller, noting that selling into the automotive market requires the participation of a major manufacturer with quality processes, global logistics and a worldwide supply chain.

May 15, 2008 in Batteries, Hybrids | Permalink | Comments (21) | TrackBack (0)


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smiles, great stuff. Competition, love it. the lower cost of production can be quite an incentive for now.

also, future of artificial photosynthesis is being discovered at US Dept. of Energy Berkley Lab

"Furthermore, it appears that this conformational change(protein) is reversible, which opens the possibility of being able to “tune” the electronic coupling between the chlorophylls and thereby modulate the energy of the chlorophylls-zeaxanthin charge-transfer state. In other words, they should be able to switch the energy-quenching process on or off."

I love this kind of research for biomimetric future. Reverse Engineering these nano bio-designs from photosyntheis to ATP synthase is just the beginning.

Imagine the future Bio-Battery, living, breathing in C02, functional energy exchange.

grrrr, Berk-e-ley that is.

and back to a comment from Jim and 500 cycles posted from another thread. With new materials science coming on board, with nano-wire research and nano-composites, it may be possible storage and charge recycle limits can be improved upon as the new nano processes are commercially accepted.

Hmmm, reduced cost and weight compared to NiMH. Maybe I'll play around with converting my motorcycle to all-electric.

Another good news on the road to vehicle electrification. Half the weight and half the price will make it an excellent competitor if charge cycles can reach 2000 or so.

More competition means much lower prices when various technologies are mass produced.

I still believe that we will see 20 KWh battery packs at $300/Kwh (USD 2007) or 200/Kwh (Euro 2007) by 2010/11. The going price may be half as much again by 2015/16.

ICE vehicles better watch out. Real competition is coming.

Aptera (another San Diego county company) should get on the phone with these guys.

They make no mention of the charge cycles - which most people think must exceed 2000.

Compare this to 109 Wh/kg and 550 W/kg in the MiEV batteries in previous post. Sounds like they've got at good product!

Small HEV batteries need high power capacity and with these batteries having almost five times higher specific power (2500 W/kg) they are much better suited to HEVs.

I think we can safely assume that HEVs will reach mass production much sooner than large capacity PHEVs.

At the risk of sounding like a pooh head:

1. NiZn don't seem much better than NiMH, maybe a bit lighter, but less lifetime, and no history. If I was to look past NiMH or Lithium ion, I'd probably look to something like the Firefly stuff, if they ever start selling the darn things.

2. Can cycle life be increased with lower power draws?

3. Maybe long term costs are MUCH lower.

4. I don't know why everyone seems to hate NiMH so much, as it is a 'good enough' technology for PHEVs, if not BEVs. (No, I do not work for an NiMH battery company....)

5. I am wondering out loud (and on line) whether ultracaps are a necessary evil for PHEV design. They are expensive and bulky, but sure solve a lot of problems with battery power draws. It bothers me a little when battery makers trumpet their power draws, when this inevitably leads to shortened life (or lower energy storage) regardless of the battery chemistry. Sometimes I think by trying to do everything (power AND energy density) they end up with something not so great.

Flame away. (Do they still call them flame wars?)

The problem NiMH is'nt that they are'nt great or even better then li-ion the problem is knowone can do anything with them for EV's until after 2015 when Chevrons patent rights stop.

Cobasys a subsidiary of Chevron owns the patents to large format NiMh batteries. They have in the past limited the production of EV capable batteries. End of story.

Re: Cobasys patent.

Hmm, I've heard they are nearing bankruptcy now. I guess the patent would still be in effect.

I'd thought large format NiMHs were too pricey anyways, but maybe that's not the case. I don't know how much it really cost to make an EV-95, for example. Maybe nobody knows.

But isn't that kind of crazy? I mean really. Isn't oil dependency a national security issue? Is there anything like intellectual emminent domain?

What are the Lithium Ion people going to do after 2015?

This all just seems so wasteful. Just dodging this technology for 10-20 years. But inevitably it will still happen.

I can't get too excited about this. Lees energy and power than li ion. Far fewer cycles. What's to like?


You are right. Patent rights can be suspended for national interests. Devil in the details, all that.

So if we had a president (VP) that didn't work for Saudi Arabia and Halliburton, respectively, we could use those patents.

The better question is why Cobasys doesn't license the patent to others and make millions of dollars, while they make millions of batteries.

You say they are owned by Chevron? Oh, never mind.

It's enough to make a person a cynic, or even to cause one to lose faith in the Free Market.

The better question is why Cobasys doesn't license the patent to others and make millions of dollars, while they make millions of batteries.

They did. 8 or 10 companies have licenses to sell large-format NIMH for vehicular use outside of North America and a couple (including Toyota/Panasonic joint venture PEVE) also have licenses to sell them inside North America. These licensees have opted not to go into production because it makes no sense to invest several years and hundreds of millions in R&D and manufacturing only to end up with a product that provides less power and energy than lithium at higher cost.


But there are no large format Lithium Ion cells. The biggest A123 is 4000 mA-hr at 3.7 volts. The safe Lithium ion cells (like the A123) are no less bulky than NiMH, though they are half the weight.

And Lithium ion has no proof of longevity like NiMH. Lithium ions have a shelf life of only about 5 years, whether you use them or not, unless they've fixed that.

High power use is better dealt with by U-caps anyway.


I thought A123's 32157 cell was 10 Ah, but I could be wrong. I'm sure the cell they're designing with GM is bigger. Also several Asian vendors sell LiFePO4 in sizes of 100 Ah or more.

Advanced lithium chemistry cycle life is much better than plain old li-ion. A 10 year calender life is harder to pin down since most of these advanced chemistry cells haven't been around 10 years. Accelerated testing can only tell you so much.

Ultracaps are OK for very short power bursts, but you can't carry enough with you to power you up a mountain pass. It's a lot simpler to just use batteries capable of doing the job.

Trinity uses u-caps to increase lifespan of their lithium ions. It's the only way, they said, that they could get their rated lifetimes from their batteries. They said they were using Lithium Iron Phosphate cells.

99% of the high power needs of a car are 10 seconds or less. In the case of the mountain pass, you turn have your engine turn on. That's way parallel hybrids may make more sense than the serial hybrids like the Volt. You have a way of using some extra power in the very rare times you need it. Without demanding too much from the batteries.

I think a battery that is high power and high energy is aesthetically pleasing and obviously simpler to design with compared with adding u-caps, but that still doesn't make it the best overall solution. Time will tell.

Jim, I never heard AFS say they use LiFePO4. Do you have a link? Everything on their web site speaks of "maximum energy storage per unit weight" and "low cost" and so forth, all of which apply to lithium-cobalt not lithium-iron-phosphate. Of course they make liberal use of 2015 data, which is to say their guess of what will be available and at what cost in 2015.

AFS fluff factor is pretty high, but they're on the right path.


Trinity may be using Lithium Cobalt. I'm not sure. Sorry. I know they are not using the standard (less safe) Lithium. And I know the batteries/u-caps/electronics takes up the entire back storage area of their Saturn VUE. There's lots of stuff packed in there.

They also said (I think) that the u-caps were needed to get the rated lifetime of 2000 cycles from the batteries.

In quantity, the conversion could be as low as $8700, which to me means that in low quantities, it would be very expensive.

Where do you get a charger for ni-zn batteries?

The reason these suck. From the PowerGenix website...

Charge Life at 15 Amp Discharge (100% depth of discharge) 200 cycles

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