NEC develops organic battery for IT use

IDG News Service - TOKYO -- Researchers at NEC Corp. have developed a type of rechargeable battery that's based on organic compounds and could be useful in a wide range of IT-related applications, the company said.
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 like lithium and cobalt, it uses an organic compound called PTMA.
The change not only makes the battery more environmentally friendly but also delivers some properties that could make it better suited to certain applications than existing batteries, said Masaharu Satoh, principal researcher and NEC's energy device technology group in Tsukuba, Japan.
Chief among these is a high power density, which indicates how much power can 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 with lithium-ion batteries. This combination points toward applications where a large amount of power is needed for a short time, Satoh said.
One such application -- providing enough power to allow a PC to back up data and shut down 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 are all that's 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 become a standard feature inside desktop PCs, unlike UPS units, which are bulky and expensive.
The prototype cells measure 55 millimeters by 43 mm and are 4 mm thick, which is about the size of a stack of three credit cards. Each cell weighs 20 grams.
The ORB has other advantages over current rechargeable battery technologies, Satoh said. It's able to maintain an almost constant voltage during discharge and loses 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 can be charged to about 80% of its capacity in just one minute, which could make it suitable for wireless applications where fast charging is advantageous, Satohsaid.
Another advantage that comes from its close structure to lithium-ion cells is that the manufacturing process is very similar, so mass production, when or if it occurs, could likely be done on existing battery production lines with only minor adjustments, Satoh said.
More work remains on fine-tuning the ORB, and NEC plans to spend the next two to three years working on possible uses for the technology as it moves toward possible commercialization.
NEC began researching the technology in 2000 and its work has been partly funded by Japan's New Energy and Industrial Technology Development Organization.