Glitch in Sanyo's battery prompts recall

Faulty Li-ion battery packs made by a Sanyo subsidiary and used in mobile phones have prompted NTT Docomo Inc. to recall and exchange about 1.3 million battery packs used in Docomo's 3G handsets.

The troubled battery pack was manufactured by Sanyo GS Softenergy Co., a joint venture company between Sanyo and GS Yuasa Corp., specializes in rechargeable batteries for portable devices. Sanyo owns 51 percent of the equity and GS Yuasa holds 49 percent.

The troubled D6 battery packs were designed for Mitsubishi's handsets, and problems are limited to Mitsubishi's models, said a Sanyo GS spokeswoman.

Thus far, a total of 18 cases of overheating and rupture have been reported. Some battery packs manufactured from November 2005 to May 2006 were found to be defective, including deformed electrode plates. The deformed plates could pierce the battery's insulating film. The damaged film could cause a short circuit, generating excessive heat or, in the worst case, a rupture.

The cost of the recall is estimated to be about $26 million to $35 million. Docomo, Mitsubishi and Sanyo are negotiating about how to pay for the recall.

- Yoshiko Hara
EE Times