LLNL develops powerful new rechargeable battery

Researchers in the US have developed and demonstrated a laboratory prototype miniature thin-film fuel cell power source, which provides portable electrical power for a range of consumer electronics.

Researchers at Lawrence Livermore National Laboratory have developed and demonstrated a laboratory prototype miniature thin-film fuel cell power source, which provides portable electrical power for a range of consumer electronics.

With the LLNL fuel cell, a typical cell phone battery could be projected to last more than 300 percent longer, extending standby time from four days to two weeks, and talk time from six hours to two days.

The miniature fuel cell technology reportedly incorporates a thin film fuel cell and microfluidic fuel processing components integrated into a common package. Using liquid fuels, such as methanol, the fuel cell power module provides greater than three times longer operating time than present rechargeable batteries.

The patented design and method for making thin-film fuel cells is said to combine microcircuit processes, microfluidic components, and micro-electrical-mechanical systems (MEMS) technology. This solution provides the consumer a lighter-weight, longer-lasting power source for replacement of existing rechargeable batteries.

Jeff Morse of the LLNL Centre for Microtechnology Engineering predicts the MEMS-based fuel cell power source will replace rechargeable batteries, such as lithium-ion and lithium-ion polymer, in a range of consumer electronics, including cell phones, handheld computers and laptops. The MEMS fuel cell is designed to be 50 percent of the cost with 30 percent of the weight, size or volume of existing rechargeable portable power sources.

‘The MEMS-based fuel cell has been designed to compete with existing re-chargeable batteries in their respective marketplaces,’ said Morse. Current estimates suggest a price of $1.50-$3 per watt-hour. The fuel cells may also create a significant alternative to disposable batteries. They could decrease the total number of batteries used by 50 percent, with a total cost of over $2 billion per year, and vastly reduce the kilotons per year of waste generated by these old technologies, many of them containing toxic metals requiring special disposal.

LLNL’s miniature fuel cell product incorporates integrated microfluidic fuel distribution architecture within a miniature fuel cell package. This feature enables the fuel cell to operate from highly concentrated methyl alcohol fuel mixtures supplied from a replaceable fuel cartridge.

The heart of this miniature power source utilises a thin layer of electrolyte material sandwiched between electrode materials containing appropriately proportioned catalyst materials.

Microfluidic control elements distribute methyl alcohol fuel mixtures through a silicon chip over one electrode surface while air is simultaneously distributed over the other electrode. Integrated resistive heaters allow heating of the electrolyte-electrode layers, thereby increasing the conduction of catalytically generated protons from the fuel supply across the electrolyte to the air breathing electrode, where they combine with oxygen to generate electrical current.

Optimisation of current output through control of the catalyst and electrode surface area, and microfluidic fuel distribution, offer a miniature energy source providing continuous power for greater than three times longer than existing rechargeable batteries.