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Are Silver-Zinc Batteries The Portable Power Breakthrough We’ve Been Hoping For?

It's been suggested that mobile consumer electronics battery technology, including laptop computers, had hit a "glass ceiling" of sorts, what with there having been no major breakthroughs in the category since the arrival of lithium ion (LiIon) batteries in the early-mid '90s. However, a firm called ZPower (formerly Zinc Matrix Power) is poised to launch a line of rechargeable, silver-zinc batteries for mobile electronics, which it claims last significantly longer than traditional lithium-ion batteries, pose no overheating or fire hazard, and are kinder to the environment as a bonus.

According to the company, this battery technology advance (which isn't completely new, but has never before been marketed for use in notebook computers, cellphones, and the like) offers 40% more runtime than traditional lithium-ion batteries (a metric that translates to two-hour runtime extending to three hours, or a five hours' runtime becoming seven hours), with the added "green bonus that more then 95% of the primary manufacturing elements can be recycled and reused. Financial incentives will be extended to consumers who recycle.

Best of all, perhaps, ZPower batteries contain no lithium and are inherently safe from the spontaneous combustion hazard that has lurked in the background with lithium ion batteries ever since the Sony-made LiIon units in a few of the early PowerBook 5300s burst into flame back in 1995, prompting Apple to recall all machines that had shipped and provisionally switch back to less-efficient but safer Nickel Metal Hydride cells for the duration of PowerBook 5300 production. They switched to LiIon again with the PowerBook 3400c, although the heat issue has remained a concern over the past decade.

Just about every major laptop computer manufacturer, including Apple (three times), has implemented battery recalls over the past eight years; Toshiba, Gateway, Acer, IBM/Lenovo, HP, Dell, Sony, and Compaq, resulting in the return of over 10 million lithium-ion batteries.

Unlike lithium-ion technology, which uses dimethyl carbonate, a flammable liquid, with their silver, zinc and water-based chemical makeup, the new ZPower batteries deliver high performance while safely powering portable devices, and aside from that peace of mind, the aqueous technology facilitates recycling and a recyclable product that reduces the environmental impact associated with most types of rechargeable batteries. Unlike traditional rechargeable batteries, ZPower batteries contain no heavy metals and no toxic chemicals. The company was awarded the AlwaysOn GoingGreen 100 Award in 2007 for energy storage.

The primary materials of ZPower batteries (i.e. silver and zinc) are both fully recyclable, which means that materials derived from recycling process are of the same quality as the materials that went into the initial creation of the battery with no degradation. In general, recycling requires only 20% of the energy needed for mining and refining new materials and allows the battery to be a long term sustainable technology.

In contrast, the majority of the elements of traditional lithium-ion batteries can only be downcycled and cannot be reused for battery production. Additional lithium must be mined from the environment to make new LiIon batteries.

ZPower has pledged that the company will make it easy for consumers to return used batteries in exchange for a credit towards the purchase of a new silver-zinc battery with a program to be introduced this year, with a leading ultra-thin notebook computer," although the company is coy about what computer that will be.

Slver-zinc batteries incorporate intrinsically safe water-based chemistry that contains no lithium or flammable solvents that will not vent with flame, so unlike lithium-ion and lithium-polymer batteries, ZPower batteries are free from the problems of thermal runaway, fire, and danger of explosion. They are also unencumbered by regulations that limit the size of lithium-containing batteries on aircraft.

Happily, silver-zinc batteries along with their other advantages also offer an extremely high ratio of energy to volume (Wh/l) making them ideal for use in notebook computers, cell phones, and other consumer electronics. ZPower claims to be the only rechargeable battery that excels lithium-ion in energy density for consumer applications, and, while Lithium-ion technology is apparently reaching a plateau in tis potential, it's early days engineering wise for silver-zinc with plenty of potential to increase both energy density and cycle life.

Camarillo, California based ZPower's company president and CEO, Dr. Ross Dueber, is a former Vice President of Emerson Climate Technologies, and also previously pursued a successful career as an officer in the U.S. Air Force whose duties included R&D and specification of batteries for aircraft and space applications and a professorship in chemistry at the U.S. Air Force Academy. Dr. Dueber also served as the manager for lithium-ion batteries at Eagle Picher where he established a new development and production group in the mid 1990s. ZPower, Inc. holds 16 key patents on rechargeable silver-zinc battery technology, and has strategic partnerships with, and venture investments from, Intel Corporation, OnPointT Technologies (a venture capital fund of the US Army), and PowerVentures--a large private equity group.

This all sounds very promising, and is cause for cautious optimism that silver-zinc could be the breakthrough in battery technology we've been waiting and hoping for over the past decade.

ZPower’s battery technology has three principal elements. For the technically-minded, these consist of:

1) Composite Polymer Zinc Anode
The zinc anode in ZPower batteries is a composite polymer electrode which inhibits shape change and dendrite growth. In the past, shape change and dendrite growth in traditional silver-zinc cells was frequently an issue. These issues have been solved with ZPower silver-zinc technology.

2) Multi-Functional, Layered Separator
A highly-effective separator stack that resists dendrite growth from the zinc anode, while simultaneously resisting degradation from the silver cathode. At the same time, it allows ions to move freely from the cathode to the anode to minimize the cell’s internal resistance. This results in a superior silver-zinc battery cell which offers long life and quick charge time.

3) Nano-Particle Silver Cathode
The silver cathode in ZPower batteries is coated with nano particles. This nano-technology enhances conductivity for lower internal resistance.

Silver-zinc batteries also enjoy the advantage of a longer shelf-life than lithium ion batteries, with negligible degradation in capacity during the first year, during which lithium ion batteries can lose up to 30 per cent of their capacity, although after the first 12 months or so silver-zinc batteries start degrading at a rate similar to LiIon units batteries.

So what of potential downsides? For one thing, silver is expensive, and in relatively short supply compared with lithium ion materials. Currently, recycled material makes up over 30% of the silver that is needed each year to satisfy world demand, and while the volume of silver required to supply batteries for the laptop computer industry, even if there was a wholesale conversion to silver-zinc battery technology, would not be likely to put any really serious pressure on the world supply of industrial silver, demand for this technology for powering so-called "plug-in" hybrid or full electric automobiles might cause the price of silver to skyrocket out of sight, analogous to the way that diversion of corn and other grain/oilseed crops to ethanol "biofuels" production has catalyzed the unintended consequence of a global food shortage and hunger crisis.

For example, the new, all-electric Tesla sports car, the first flagship store for which just opened yesterday in the Westwood neighborhood of Los Angeles, is powered by a 1,000 pound bank of 6,831 (!) lithium ion laptop computer batteries. It's doubtful that enough Teslas will ever be sold to seriously threaten availability and price stability of silver, but once electric car technology makes the jump to more practical vehicles with mass-market appeal, such as the plug-in hybrid Chevy Volt which is slated to start production in 2010, watch out.

In the meantime, it will be interesting to see if silver-zinc battery technology will gain traction in the laptop computer market, and whether Apple will opt in.

For more information, about ZPower silver-zinc batteries, visit:
http://www.zmp.com/index.htm



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cmoore@macopinion.com


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