Investors all charged up for US battery firms

Two US battery startups targeting opposite extremes of the energy storage market secured significant financial backing this week as investors gave a ringing vote of confidence to the fast-expanding sector.

Infinity Power Systems raised $20m in series C financing to continue the development of its thin-film battery business, while 24M, a spin-off from battery giant A123Systems, raised $16m to support its work on utility-scale batteries.

Infinity, which raised $13m in series B funding in March 2008, and $34.7m in 2006, raised its latest round through existing investors, with the help of new participant General Investment Management.

The company, which is already selling its range of Thinergy solid-state batteries, will use the new capital to help expand manufacturing and sales channels for the devices.

Thinergy thin-film batteries are designed to replace coin batteries and supercapacitors for use in tiny physical devices such as RFID chips and powered smart cards. The devices are designed to use energy harvested from movement – such as the up and down jiggling of a sensor during transportation, for example – enabling them to be constantly charged.

At the opposite end of the spectrum, 24M was officially spun out from A123Systems earlier this month to focus on the development of giant flow batteries.

The company is working to increase the density of traditional lithium-ion chemistry by combining fuel cell and flow battery technology, in which electrolytes stored in tanks are used to recharge a battery device.

24M reckons the technology will result in large-scale energy storage devices suitable for storing energy produced by intermittent renewable power sources, such as wind and solar farms.

MIT professor Yet-Ming Chiang, whose research led to the increased power density in A123's lithium ion cells, will head up the company with colleagues.

The company said that $10m of the latest funding will come from private investors Charles River Ventures and North Bridge Venture Partners, while the remaining $6m will be provided by the Department of Energy.