PARIS — As part of a research collaboration on miniaturized energy sources, the French Atomic Energy Agency (CEA) and STMicroelectronics NV (Geneva, Switzerland) have unveiled a hydrogen fuel cell for mobile phones that aims to reduce dependency on the use of electrical power supplies to recharge batteries.

The miniature fuel cell is made using microfluidic structures etched into the back surface of silicon and a reaction interface at the silicon surface. This works together with a hydrogen-filled cartridge, the size of a small cigarette lighter. Currently at the prototype stage, the final product is due to be commercialized by the end of 2009 or early 2010.

“Five years ago, a cell phone used one watt of power while a 3G phone now uses from 3 to 5 watts. With the incoming generation of cell phones, if we do not change the battery, the autonomy will be reduced by one third, limiting access to multimedia services,” said Didier Marsacq, director of CEA-Liten, the Laboratory for Innovation in New Energy Technologies and Nanomaterials, at a press conference held at CEA headquarters in Paris.

The proliferation of mobile devices has generated an exceptional demand for rechargeable batteries, but the existing solutions leave much to be desired in terms of performance, operating life and environmental impact, according to CEA-Liten.

Lithium-ion (Li-ion) technology represents the fastest growing rechargeable battery market, according to the Santa Clara Consulting Group (Santa Clara, Calif.) and Japanese and Korean firms, including Sony, Sanyo and Matsushita, LG and Samsung hold about 70 percent of the market.

Marsacq said CEA’s energy source comprises a hydrogen-based fuel cell core unit (FCCU), developed jointly by CEA-Liten and ST, an energy management unit (EMU) developed by ST, and a hydrogen cartridge developed by Bic (Clichy, France), a manufacturer of cigarette lighters, ballpoint pens and shaving razors.

Architecture of a silicon-based micro fuel cell. (Source Artechnique/CEA)

The cathode, protected by a pierced coating that lets air (oxygen) in tops the polymer membrane used as electrolyte. Below, the anode is accessed via channels with gaseous hydrogen coming in. All is built on a silicon substrate using microelectronics process technologies.