Panasonic parent Matsushita today announced what it claims is a "safe" lithium-ion rechargeable battery. The secret: inserting a layer of heat-resistant insulating material to prevent fire-starting internal short-circuits of the kind that ignited a number of notebooks this year.

Typical lithium-ion batteries embed the positively charged anode and the negatively charged cathode in power-generating chemicals separated by a polyolephine plastic barrier. That, said Matsushita, isn't sufficient to prevent short-circuits and the build up of heat that can lead to the explosive destruction of a battery.

Inserting a layer of insulated metallic oxide, however, does provide just such a barrier, the company said.

The lithium-ion battery was commercialised by Sony in the early 1990s following almost two decades of development work. Ironically, it was Sony batteries that caused the spate of laptop fires over the past 12 months or so which culminated in Dell and Apple separately recalling a total of more than 6m batteries. Toshiba, Lenovo and IBM soon followed suit, and shortly afterward Sony said it would support any other of its PC vendor customers who chose to implement recalls.

Matsushita's "safe" battery is a cylindrical, 2.9Ah unit designed to by combined into so-called 'three-cell' and 'six-cell' battery packs for use in notebooks. ®