The announcement comes in a year when almost all major notebook manufacturers were forced to recall flawed notebook battery packs supplied by Matsushita rival Sony, including a 4.1 million battery recall initiated by Dell, Round Rock, Texas. Dell's recall caused a major stir in the industry, after months of bad publicity over notebooks that caught fire due to a battery pack flaw. Soon, other vendors including Apple, Lenovo, Toshiba and Fujitsu announced recalls of Sony-based notebook batteries.

Matsushita, based in Osaka, Japan, said its battery unit "has succeeded in improving the safety by forming a heat resistance layer (HRL) consisting of an insulating metal oxide on the surface of the electrodes. Lithium-ion batteries contain a thin polyolefin separator to insulate the cathode from the anode. When a separator is pierced by an electrically conductive material such as a metal particle, a short-circuit develops, causing the battery to overheat and, in the worst case, catch fire."

"The HRL used in the Panasonic battery, however, has better insulating and heat-resistant characteristics than polyolefin. Even if a short-circuit occurs, it will cease without causing the battery to overheat," the company said. "The HRL technology has enabled (Matsushita) to increase energy density and mass-produce safer lithium-ion batteries."

U.S. regulators, including the Consumer Product Safety Commission, have been investigating hazards connected to lithium ion batteries for several years. In the case of the Sony batteries, the company admitted that a flaw in a production line led to contaminants inside battery packs that were shipped to notebook makers.

Matsushita's unit said its process has undertaken steps to ensure that lithium-ion batteries are not contaminated with "electrically conductive materials" and has created a "clean environment" in its battery factory.