Sanyo has developed a rechargeable battery that can be supplied to users ready-to-use.

The new battery enables charging at the time of manufacturing so users don't have to charge them as soon as they pull them out the box.

The new battery is a nickel metal hydride (NiMH) cell of the type commonly found in many portable electronics products but with a key difference. Typically, NiMH batteries lose charge over time if they are not used. Consequently, the gap between their manufacture and sale means it's not feasible to supply them charged to users. Sanyo's new battery loses energy much more slowly when unused so batteries can be supplied that are ready to use at the time of purchase.

Sanyo said its new battery loses about 15 percent of its charge after a year of no use compared to competing batteries that lose almost all their charge over the same period.

The battery technology, which will be used in an AA-battery that will go on sale in Japan in the middle of this month, is the first product to be born from Sanyo's "Think Gaia" corporate restructuring plan. Under the leadership of Chairman Tomoyo Nonaka, Sanyo is attempting to refocus around environmentally-friendly products.

Sanyo will promote the batteries as a replacement for throw-away dry cell batteries, of which around 40 billion are disposed of worldwide each year, according to industry figures cited by Sanyo.

The batteries, carrying the "Eneloop" product name, will go on sale starting 14 November. A pack of two AA batteries will cost 1,155 Yen (£5.60). They will also be available in packs of four and eight, and also with a recharger. AAA-size batteries in the same range will go on sale in Japan in January.

The company estimates the new batteries will reach the end of their useful life after they have been recharged about 1,000 times. Sanyo said the batteries are environmentally friendly and can be recycled.