Mercury/Lead-free Silver Oxide Battery
- Its Production Starts at a Newer, More-Sophisticated Plant October 2005 -

SII Micro Parts Ltd. (SMP), one of the subsidiaries of Seiko Instruments Inc. (SII), announced today that it has developed a mercury/lead-free silver oxide battery. Starting November 2005, mercury/lead-free batteries will be marketed on a worldwide basis. SMP is developing, manufacturing and marketing batteries, capacitors and other electronic components. Successfully starting manufacturing this new type of the battery at a newer, more-sophisticated plant equipped with state-of-the-art production equipment enables SMP to offer high reliability mercury-free silver oxide batteries with minimum quality deviation. The plant will be constructed within the site of SMP’s head office in Sendai, Miyagi Prefecture, and accomplished autumn 2005.

Silver oxide battery is a button type cell mainly used in wristwatches and other small-sized devices. Sendai Seimitsu Zairyo Research Institute (predecessor of SMP) started its business of manufacturing and marketing silver oxide batteries in 1975, and SMP is now producing
20 million silver oxide batteries per month. The European battery directives, for which revisions are currently made in the EU, determine that sales of batteries containing mercury of 5 ppm or more are prohibited. However, freeing mercury from silver oxide batteries is an exception due to the technological difficulty in achieving it.

SMP started its study to eliminate the impact of batteries on the environment 14 years before growing global concern over environmental issues, and, as of August 2005, SMP has succeeded in freeing mercury from silver oxide batteries. Freeing mercury and lead as well from silver oxide batteries will lead to the dramatic contribution to protecting the environment.

Silver oxide battery is a small-sized primary cell using silver oxide as the positive electrode, Zinc as the negative electrode and an alkaline electrolyte. Zinc, the active material in the negative electrode, will corrode in alkaline solution, and thereby local cell reaction will happen between Zinc and its contacting collector electrode, and it will be consumed. This may also cause the expansion of the cell or leakage of the inner electrolyte due to generation of hydrogen gas. In the past, minute amounts of mercury or lead were just added to the battery to suppress the above problems.

SMP’s unique and proprietary micro machining technology was conducive to developing this mercury-free silver oxide battery. Additionally, adopting the high-accuracy negative collector electrode surface process technique has successfully resulted in the accomplishment of equal or better performance to or than the company’s conventional silver oxide batteries without using mercury or lead as an anti-corrosion material. In particular, SMP has succeeded in dramatically improving discharge characteristics at low temperatures and leakage resistance characteristics as well.

SMP will target to free mercury from silver oxide batteries of all kinds and will continue to proactively tackle R&D with the aim of minimizing the impact of batteries on the environment.

SMP’s Unique and Proprietary Technology Indispensable to Develop a Mercury-free Silver Oxide Battery

1. SMP’s unique anti-corrosion technology ideal for zinc powder and negative collector electrode improved leakage resistance
• High precision negative collector electrode surface process technology developed this time is originated in SMP’s proprietary battery manufacturing technology.
• A high corrosion resistant zinc alloy was newly adopted.
• A corrosion inhibitor was independently developed.
• Combining and synergizing the surface process technology and the zinc powder corrosion inhibitor improved leakage resistance up to about 1.5 times as high as that of the company’s conventional batteries (patent pending).

2. Adopting unique crimping technology allowed internal resistance to be reduced and product reliability to be improved
Applying micro machining technology SMP has honed and built up for a long period of times allowed the company to develop an ideal crimping technology specifically used in button-type silver oxide batteries. This achieved a 40% reduction in internal resistance compared to that of the company’s conventional batteries and also significantly enhanced product reliability. In addition, this achievement contributes to improving leakage resistance (patent pending).

3. Adopting a high performance electrolyte allowed low temperature characteristics to be drastically enhanced
In general, freeing mercury from silver oxide batteries will not only accelerate corrosion of zinc powder, but also deteriorate discharge characteristics. Especially, it will be more apparently noticeable when a drop in temperatures happens. To suppress deterioration, SMP has developed a high performance and alkaline-based electrolyte. Adopting this high performance electrolyte enabled the company to widen the operating temperature range from -10 ºC to 60 ºC to -20 ºC to 60 ºC (patent pending).

[Production Framework]
• State-of-the-art production equipment will be introduced in every clean room at the new high-tech plant designed to produce mercury-free silver oxide batteries with minimum quality deviation.
• As for the monthly production capacity, 10 million units are projected for fiscal 2005,
20 million units for fiscal 2006 and 30 million units for fiscal 2007.

[About SII Micro Parts Ltd.]
Corporate name: SII Micro Parts Ltd.
Head office: 45-1, Matsubara, Kami-ayashi, Aoba-ku, Sendai-shi, Miyagi, Japan 989-3124
President and CEO: Takeshi Sasaki
Pain-in capital: 487,000,000 yen
Shareholder’s interest: 55% Seiko Instruments Inc. (SII)
45% Japan Industrial Partners, Inc. (JIP)
Business lines: Development, manufacture and marketing of batteries, capacitors,
rare earth magnets, other electronic components, and special metallic materials for use in micro precision devices
Payroll: Approx. 300
Established: November 29, 1994

[About a New Plant]
Address: 45-1, Matsubara, Kami-ayashi, Aoba-ku, Sendai-shi, Miyagi, Japan 989-3124
Building area: 1618 m2
Total floor area: 3100 m2
Total investment: Approx. 1,000,000,000 yen
Production capacity: 20 million units per month Production startup: October 2005 (planned)

Contact Information
Press Contact
Seiko Instruments Inc.
Corporate Communications Dept.

Product Inquiry
SII Micro Parts Ltd.
Fax :+81-22-391-9330

The content of this news release is based on the information as of the release date. Please note that the content may not be always up-to-date.