NEC develops organic battery for IT use

NEC has developed a new type of rechargeable battery that is based on organic compounds and could be useful in IT applications.

Researchers at NEC have developed a new type of rechargeable battery that is based on organic compounds and could be useful in a wide range of IT-related applications, they said last week.

The Organic Radical Battery, or ORB, is based on a similar cell structure to a Lithium Ion battery, of the type commonly found in devices such as notebook computers and cell phones, but with one significant difference: instead of using poisonous ingredients such as lithium and cobalt it uses an organic compound called PTMA.

The change not only made the battery more environmentally friendly but also delivered some properties that could make it better suited to certain applications than existing batteries, principal researcher and NEC's energy device technology group, Masaharu Satoh, said. Chief among these was a high power density, which indicated how much power could be supplied for its size.

An ORB can deliver much more power than a Lithium Ion battery of the same size. However the energy density, which relates to how long the power can be supplied, is lower than Lithium Ion.

This combination pointed towards applications where a large amount of power is needed for a short time, said Satoh.

One such application - providing enough power to allow a PC to backup data and shutdown properly in the event of a main power failure - has been used by Satoh and his team to demonstrate the technology.

Four of the small, thin ORB cells were all that was required to keep a desktop PC running for the 10 or 20 seconds required to carry out such an operation, he said.

It's not the same as an uninterruptible power supply (UPS), which can typically power a PC for about an hour, but the small size and likely low cost or the ORB means it could potentially become a standard feature inside desktop PCs, unlike UPS units which are bulky and expensive.

The prototype cells measure 55mm x 43mm, are 4mm thick, which is about the same size a stack of three credit cards. Each cell weighs 20 grams.

The ORB had other advantages over current rechargeable battery technologies too, Satoh said. It was able to maintain an almost constant voltage during discharge and also losr its ability to be fully charged at a much slower rate than competitors.

The battery can also be charged very fast.

With enough current supplied the battery could be charged to about 80 per cent of its capacity in just one minute, which made it suitable for wireless applications where fast charging was advantageous, he said.

Another advantage that came from its close structure to Lithium Ion was that the manufacturing process was very similar and so mass production, when or if it occured, could likely be done on existing battery production lines with only minor adjustments, Satoh said.

Some more work remains on fine-tuning the ORB and NEC plans to also spend the next 2 to 3 years working on possible uses for the technology as it moves towards possible commercialisation.

NEC began researching the technology in 2000 and its work has been partly funded by Japan's New Energy and Industrial Technology Development Organisation (NEDO).