Sony is looking at model airplane battery technology for its next laptop battery design.

Lithium ion polymer (LiPo) batteries are lighter than current metal-cased lithium ion batteries, much less flammable and can also be moulded to fit complex spaces inside equipment.

Lithium ion batteries have a lithium ion electrolyte held in an organic solvent which is flammable and stored in a rigid metal case. A LiPo battery has the lithium held in a gel-like polymer such as polyacrylonitrile and needs no metal case, making it lighter. The energy density of LiPo batteries is about 20 percent better than lithium ion ones. This has made them popular with radio-controlled model plane enthusiasts.

Lithium ion batteries have run into severe flammability problems, particularly affecting Sony-made units. This has prompted massive notebook computer recalls to remedy the problems. Sony, as a battery manufacturer, and notebook makers Dell, Apple, Lenovo, and Toshiba were all affected by this. As a result lithium ion battery technology is now seen as a dead end.

It's partly the consequence of making lithium ion batteries more powerful to keep notebook battery life up whilst power consumption has been increasing. Stan Glasgow, president of Sony Electronics, said that: "There is not too much more power we want to cram into lithium ion."

The IEEE organisation is developing a new battery standard as a result of battery safety concerns. It should be available some time in 2008.

LiPo batteries first appeared in about 1996. Mitsubishi tried using them in its expensive, unreliable, and consequently unsuccessful, Pedion notebook computer in 1997. Sanyo has recently developed a LiPo battery less than 4mm thin. LiPo batteries are now used by Apple in its MacBook Pro notebook computers. They are also found in some portable gaming devices.

However there have been reports of some LiPo battery fires. The charging of the batteries has to be done in a more controlled way to avoid fire and/or explosions caused by overcharging.