Energy density

Four Japanese companies – Omron, Mitsui, Okamura Laboratory and Power Systems – have formed a joint venture to commercialize a new type of capacitor.

The EcaSS, as the new capacitor is called, is a storage device that was invented in 1992 by Michio Okamura, President of Okamura Laboratory. Its energy density is greater than that lead-acid batteries and nickel-metal-hydride batteries, and comes close to that of lithium-ion batteries.

The group aims to commercialize the technology, aiming for devices with an energy density of 40Wh/kg (equivalent to the effective capacitance of nickel-metal-hydride batteries) in 2004 and 60Wh/kg (nearing the effective charge capacity of lithium-ion batteries) in March 2005.

To do so, the companies plan to invest 2.5 billion yen to allow them to mass produce the devices over the next three years. The four are aiming to achieve a production capacity of 300,000 cells per month during 2007. The cells will be produced at a mass production line that will be set up at Omron’s facilities by Power Systems.

The companies aim to achieve sales of over 10 billion yen in the fiscal year ending March 2007.

Last month, another Japanese capacitor vendor JEOL announced that it too had formed a joint venture for the further development and production of its ‘nanogate’ capacitor. The 70 million yen joint venture was formed between JEOL and Nikko Antfactory, Diamond Capital and Vision Capital Corporation.

In October 2003, JEOL announced that it had succeeded in developing a nanogate capacitor with 50 to 75Wh/kg energy density.