updated 09:25 pm EDT, Tue August 12, 2008
Zpower zinc-silver battery
Zpower, a provider of silver-zinc battery technology, announced the inclusion of their silver-zinc cells in a major notebook computer in 2009. Zpower claims their batteries have run-times up to 40 percent longer than comparable Lithium-ion cells, while simultaneously offering safety and environmental advantages. Zinc-silver batteries have almost been forgotten about but improvements in materials and manufacturing processes have brought them to compete in a market currently dominated by Li-ion cells.
Zpower has made improvements in battery cycle life, quality, and consistency over previous zinc-silver cells. Attempts to develop this technology in the past ran into problems with zinc electrodes degrading or the cellophane separator failing. These factors limited the number of charge cycles before battery failure. Zpower integrated new materials, overcoming the problems, to increase the cycle life and dependability.
Consumers will be attracted to the longer run times of zinc-silver, claimed to exceed Li-ion by up to 40 percent. Zpower claims the power density of zinc-silver is the highest of any battery in the consumer market. There is still great potential to further develop the technology. Where Li-ion advancements seem to have reached a plateau, the silver-zinc batteries have potential to increase performance significantly in the near future.
The safety of Li-ion cells has been questioned by the public after a number of incidents involving batteries catching fire or exploding. Zpower claims the water-based chemistry used in their zinc-silver cells is not flammable and does not have problems with thermal runaway that are associated with Li-ion chemistry. Low flash point electrolytes and exothermically degrading materials contained in Li-ion batteries occassionally cause fires or explosions. Silver-zinc cells are much more stable. Large shipments of Li-ion batteries are restricted from pasenger aircraft cargo and loose Li-ion batteries are not allowed in checked baggage. For these reasons the government has been using silver-zinc batteries in missiles, torpedoes, or electronics to be sent into space.
According to Zpower, 95 percent of the materials in the batteries are recyclable. There are no heavy metals or toxic chemicals contained in the batteries. The raw materials extracted from the used cells retain their quality, making recycling more effective. Zpower is one of the first companies to offer financial incentives to customers that choose to recycle their batteries.