Matsushita announced it created new Li-ion rechargeable batteries with a 20 to 40 percent higher cpaacity than current Li-ion batteries. In the case of a standard-sized (so-called "18650 size") cylindrical battery for use in notebook computers, the capacity will be increased from the current 2.9 Ah to 3.6Ah. The energy density per volume is also increased to 740 Wh/L, which is 40% higher than that of the company's existing product. The exhibition relating to this battery is on display at the 2007 International CES being held from January 8, 2007 in Las Vegas.
The new battery uses an alloy material for the negative electrode instead of a commonly used carbon material (graphite carbon). The capacity of battery is increased by using a material with the logical discharge capacity per electrode that is several times higher than that of graphite carbon. The two companies aim to commercialize the product within a few years, targeting the use in notebook computers. The companies claim that the cut-off voltage reaches 2.0 V while the charging voltage is 4.2 V.
Si- and Sn-based materials are commonly used as the alloy material. Thus far, Sony Corp. launched Nexelion, a Li-ion rechargeable battery whose capacity has been increased by about 30% with the use of a Sn-based amorphous material for the negative electrode. Matsushita Battery has not yet revealed the composition of the alloy material used.
Matsushita Battery has employed what the company regards as a safety technology in the newly developed battery. A heat-resistant layer made of insulating metal oxide is provided on the surface of the negative electrode plate. This ensures improved safety while maintaining a current capacity as high as 3.6 Ah.