Japan's Matsushita Electric Industrial Co (Panasonic) claims to have developed a lithium-ion battery that won't overheat even if a short circuit occurs.

The new battery includes a heat-resistant insulator inside the battery cell, next to an existing separator that insulates the anode and cathode. If that separator is punctured a short circuit occurs, which typically causes the battery to overheat and, in some circumstances, catch fire. Panasonic said its insulator layer ensures that the battery won't overheat even in the event of a short circuit.

Panasonic's announcement responds to consumers' concerns about the safety of lithium-ion batteries following a number of incidents involving them.

Earlier this year most major laptop computer makers launched recall or exchange programs for batteries containing lithium-ion cells made by Sony after a number of batteries overheated and caught fire. Sony blamed the problem on metallic particles that got inside the battery during production, puncturing the separator layer and causing a short circuit. The replacement program covers 9.6 million batteries and will cost Sony up to ¥51 billion.

Then on 7 December, Japanese mobile-carrier NTT DoCoMo and handset-maker Mitsubishi Electric recalled 1.3 million mobile phone batteries made by Sanyo Electric, saying they could overheat and catch fire.

Panasonic's new batteries are made by another company in the Matsushita group, Matsushita Battery Industrial Co, and are ready for mass production, said Akira Kadota, a spokesman for Panasonic in Tokyo. The batteries aren't available directly to end users but are sold in bulk to electronic product manufacturers, so Panasonic wouldn't reveal their price. Kadota said they could be more expensive than current cells but could work out cheaper if large orders are placed.

Matsushita Battery Industrial is one of the largest battery makers in Japan.