Mobile

Nokia Japan, the Japanese unit of Finland's Nokia Corp., held an emergency press conference Aug. 24, 2007, regarding the incidents of fires caused by battery packs used in its products (Figs. 1 and 2).

The defective component is the BL-5C lithium-ion rechargeable battery pack used in some of Nokia's mobile phones. The company announced the incident Aug. 14 and started to offer free replacement for BL-5C.

Tyler McGee, president of Nokia Japan, said at the meeting that the company submitted a report on this battery pack to Japan's Ministry of Economy, Trade and Industry (MITI) on that day. He also explained the background of two incidents in Japan, from the occurrence to the announcement of the voluntary recall.

President McGee said that the first failure occurred July 28 in Osaka and was reported to Nokia Japan from a communications operator July 30. Nokia Japan informed its regional front offices of the problem and set up an investigation team July 31. The company was reported Aug. 6 that the first failure was recognized as a fire incident.

The second defect occurred Aug. 7 in Shizuoka. It was reported from a communications operator to Nokia Japan Aug. 8. The company notified its regional front offices of the second incident on the same day and obtained the battery pack and handset affected by the second failure.

Matsushita Battery Industrial Co. Ltd. started to investigate the causes of first and second incidents respectively Aug. 13 and 9. Nokia announced "Product Advisory" on Aug. 14 concerning free replacement of the battery pack in question.

Cause of incidents under investigation

"According to the initial investigation, the battery pack could potentially experience short-circuiting or overheating while charging due to the defects rarely produced during the production process," Nokia Japan said in the report regarding the incident submitted to MITI. "Such short-circuiting only occurs after the battery has been recharged at least 200 times."

Regarding the problem in the production process, McGee said, "We have obtained the record of production process from Matsushita Battery. We cannot announce the cause because we are currently investigating the problem."

"The incidents occurred only in battery packs supplied by Matsushita Battery," McGee said, emphasizing this point. "Packs from other manufacturers don't have the problems."