DoCoMo recalls 1.3 million cell phone batteries

TOKYO-Japanese carrier NTT DoCoMo Inc. said it will recall 1.3 million cell phone battery packs produced by Sanyo Electric Co. after learning that a few of the batteries have generated enough heat to cause ruptures.
The service provider said the problematic batteries are installed in Mitsubishi Electric Corp.’s D902i phones, which are not available outside of Japan. DoCoMo said the lithium-ion batteries were manufactured through May and owners of the affected phones will be notified directly by mail and will receive replacement batteries.
The problem is due to deformed electrode plates installed in the batteries, DoCoMo said in a press release.
“If the batteries are accidentally subjected to a strong external impact that results in a surface dent or similar depression, the deformed plates could pierce the batteries’ internal insulation, resulting in an electrical short during, or right after, charging,” the company said.
DoCoMo confirmed that so far one D06 battery has ruptured due to the problem, and 17 cases of DO6 batteries overheating have been reported. The company further noted that in a number of these cases the malfunctioning batteries had been subjected to “extremely strong impact.”
Meanwhile, DoCoMo also divulged that for the first time in its history it lost subscribers on a monthly basis. In November, the carrier saw 17,500 depart for other carriers as government mandated number portability became available, making it easier for users to churn.
The company’s battery problems come on the heels of laptop battery recalls from Sony Corp. after some of its lithium-ion power packs overheated and burst into flames. Kyocera Wireless Corp. and other cell phone makers have had similar troubles with batteries.