Watershed for silver-zinc? --- The InterviewVince Biancomano...

Watershed for silver-zinc? --- The Interview

Vince Biancomano
Courtesy of Power Management DesignLine
(03/03/2008 10:50 PM EST)

Manhasset, NY—Silver-zinc batteries are at the doorstep, poised to do for the next generation of portable electronics what the lithium-ion battery did for the Sony Camcorder in the early 1990s. Will it happen? You decide. Our recent interview with Ross Dueber, president and CEO of Camarillo, California-based ZPower, the company behind the new technology, will get you well acquainted with the technical basics and practical considerations.

PMDL: Why a new battery technology to replace lithium-ion?

RD: Higher energy density, lighter, and safer. We think silver-zinc is the next battery technology to replace lithium-ion. Historically silver-zinc has been used by the military and the aerospace industry. It's what we call a high energy-density battery, puts a lot of energy into a small light package. It's been to the moon and it's in spacecraft and been used in submarines as well. It has a history of delivering high energy density.

Why haven't we seen it commercialization over the years? It's fundamentally been plagued by a short cycle life—20 to 25 recharge cycles. We think silver-zinc has the best capability to replace lithium-ion from a performance standpoint, to deliver a higher energy-density (watt-hours for a given volume or mass), and we can also do it in a chemistry that's energetically very high-energy but also one that is very safe. We use a water-based electrolyte instead of a highly flammable electrolyte like lithium-ion. As for materials to keep the cost down, we want to recycle and reuse the materials that are in there, do it quite readily, and we want to provide financial incentives for customers to return batteries at the end of their life, in order to recapture these materials. And also to give them credit for purchasing the batteries in the first place to keep the cost down by recyling the metals over and over again.

PMDL: Where will this battery make its debut?

RD: The first battery this summer is for a new notebook computer for a customer, and that really will be the first application for a silver-zinc for consumer electronics that will actually be able to handle a lithium-ion battery or a silver-zinc battery. That will be the first of what we hope will be many platforms that can handle silver-zinc.

PMDL: How old is this battery technology? Is this a technology that's been around for 50 years, and now you've decided that this is going to be used for portables, or is this an updated technology that's been used for 5 years and now it's suited for portables?

RD: The military has been using this technology as a rechargeable battery for the last 50 or 60 years. We saw it in such programs as the Apollo Program. Very large batteries, but again with limited cycles for rechargeability. We've focused on the inherent advantages of the technology and worked on the design and chemistry in order to turn it into a good rechargeable battery for consumer electronics applications.

PMDL: Who's the competition? Who's seen the potential?

RD: We don't have any competitors in the silver-zinc chemistry field. The existing people that supply the military have been using technology that's been invented a half century ago. There's really no great demand in the military to update that technology. We saw an opportunity to look at the technology and give it a totally fresh approach. The market is very receptive for a new technology to replace lithium-ion. At the same time, various industry analysts are certainly aware of ZPower. But to state that silver-zinc commands, say, 10 percent market share, well you won't see that on any pie chart.

PMDL: In terms of the actual capabilities, what do we have? And are we talking about one particular battery for one particular application, or a series of batteries that would cover a wide range of applications in the portable market?

RD: We're talking about a series of batteries that will cover a wide range of applications. You know, from notebook computers, ultra mobile PCs, to smart phones to digital cameras. Anywhere where a lithium-ion battery would be used, we see a potential market for silver-zinc.

What we're doing is working with a key manufacturer to introduce the product into the notebook market. That will be our beachhead, so to say. Much like Sony Camcorder was the beachhead for lithium-ion batteries. And we're not looking at current devices. We're looking at next-generation devices.

PMDL: What of the specific capabilities of this battery in terms of voltage, current, and all the rest? At the same time, what has to be done to modify it for the next generation of devices? And what are the actual capabilities with respect to energy density? What are we talking about in terms of comparison to lithium-ion and size and weight considerations?

RD: In terms of what has to change, that depends on the platform. But the voltage is 1.5 volts per cell. So it's different from the 3.6 volts at which lithium-ion operates. But as we worked with the first notebook manufacturer on their systems initially based on lithium-ion, there had to be some firmware changes, and spec changes to a power supply that has a slightly lower cutoff voltage in order to handle the lower voltage of our battery. That's fundamentally it. We've been able to accommodate a lot of the handshaking in our smart battery bus interface so that we can utliize as much of the design nuances and characteristics of lithium-ion. But it's not a big material change for anybody.

PMDL: Are we talking about the same voltage range as lead-zinc?

RD: The current alkaline batteries in use, the disposable zinc-manganese dioxide batteries, are 1.5 volts. NiMH and NiCd are about 1.2 to 1.4. And lead-acid is at 2 volts. The zinc-carbon cells are at about 1.5 volts as well.

PMDL: In terms of the NiMH and NiCd that various vendors want to do away with, will silver-zinc play in this area?

RD: Perhaps you've heard of the phase-out of NiCd. The EU has been pushing to rid the content of NiCd simply from a toxicity and environmental issue. And Toys "R" Us recently made an announcement that they are not going to allow NiCd in any of the toys they sell. That certainly is moving the world towards NiMH in that arena.

It's a fairly small portion of the market in comparison to lithium-ion in portable electronics, which dominates the market. It's approximately a seven billion dollar market in these electronic devices, of which $5 billion are lithium-ion, and the remaining is NiCd and NiMH. Silver-zinc is not intended as a replacement for NiCd and NiMH. But where you need high energy density (laptops, smart phones), that's where we're really targeting.

PMDL: What about the specific energy capabilities compared to lithium-ion? What is going to be the operating parameters of this specific range of silver-zinc batteries as compared to lithium-ion?

RD: We're looking at as much as a forty percent improvement in energy density (watt-hours per liter). And a comparable cycle life—several hundred full charge/discharge cycles. And about a ten percent of improvement in watt-hours per kilogram for a specific energy.

PMDL: What specifically about current, in mA-h?

RD: The first battery we're coming out with is a 5.8 A-h battery.

PMDL: What's the size?

RD: This particular cell is meant to replicate what's referred to in the lithium-ion world as a "103450" —that is, 10 mm thick, 34 mm wide, 50 mm high.



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