Japan – eco-friendly button cell battery to be released

Japanese SII Micro Parts Ltd. (SMP) has developed a mercury/lead-free silver oxide battery and will put it on the market in the spring of 2006. SMP is a subsidiary of Seiko Instruments Inc. (SII), a Japanese electronic components manufacturer.



Japan for Sustainability reports that silver oxide batteries are small button-type cells mainly used in wristwatches. Conventional silver oxide batteries contain a small amount of mercury or lead as an anti-corrosion agent. By developing and adopting unique technologies, SMP has succeeded in manufacturing silver oxide batteries without mercury or lead. Its high-accuracy negative collector electrode surface process technology enabled the mercury/lead-free cell to achieve equivalent or better performance than a conventional cell.



SMP‘‘s unique crimping technology reduced internal resistance by about 40 percent, which also contributed to improving its leakage resistance. Its newly developed high performance electrolyte also made it possible to widen its operating temperature range to minus 20 – plus 60 degrees Celsius, compared to the conventional range of minus 10 – plus 60 degrees Celsius. SMP has been studying how to reduce the environmental impact of batteries since 1991, and now, in August 2005, it succeeded in eliminating mercury and lead from silver oxide batteries. Adopting Environment Label Type II (equivalent to ISO14021), the company has been expanding its green products manufacturing and aiming at the green purchasing market