CMR’s power moves

Business travellers without access to a dedicated power source will be able to continue working on their laptops using a new hybrid fuel-cell power-supply system.

CMR Fuel Cells, based in Cambridge, has demonstrated a prototype direct-methanol fuel-cell (DMFC) system that fits into a small cartridge and can be plugged into lithium-ion battery-powered laptops through its power socket.

When the lithium-ion battery charge runs down, the battery communicates with the fuel-cell system to turn on and supply the rest of the user’s power needs. The system is able to generate 25W from a less-than-200ml-sized container.

‘The whole purpose is to extend the battery life of a laptop to a full working day,’ explained Jill Shaw, chief operations officer at CMR Fuel Cells.

CMR’s DMFC is currently in prototype stage, but the company has already received interest from an undisclosed Taiwanese supplier to laptop manufacturers. Shaw said the supplier is interested in incorporating CMR’s DMFC into their products at the end of next year or early 2011.

The DMFC system under development at CMR will work with a lithium-ion battery being developed by the Taiwanese partner. The total package will be designed to provide more than eight hours of independent power for a laptop from a single fuel cartridge.

DMFCs are a variant of proton exchange membrane fuel cells, which contain an anode and a cathode and an electrolyte in the middle, only it relies on methanol as a fuel without pre-reforming it into hydrogen.

With a DMFC, liquid methanol is fed into the fuel cell and oxidised in the presence of water at the anode to generate carbon dioxide and hydrogen. The positive hydrogen ions produced will pass through the electrolyte to the cathode where they will react with oxygen from the air to produce water. The electrons produced will be transported from the anode to the cathode through an external circuit to supply power for connected devices.

When the methanol supply is depleted, it can be replaced by inserting a new methanol cartridge.

Shaw said the novelty of CMR’s DMFC is that in terms of its power capacity it is very compact. ‘It’s much smaller than anything else out there,’ she said. ‘We are able to get 25W out of less than two litres.’

Shaw estimated the current prototype size was about 1.8 litres but that volume could be shrunk in the future.

DMFCs are known to be able to produce a high amount of energy in a small space over a long period of time, and some people working in the portable power industry see them as a possible candidate to replace lithium-ion batteries in the future.

Shaw said that this would still be an incredible technical challenge for laptops and the best idea right now is a hybrid solution.

The CMR fuel-cell cartridge would be lightweight enough for a business traveller to take on an aircraft to keep their laptop powered up during a long flight.

Shaw said it is perfectly safe to use and methanol has been approved to carry on aeroplanes. However, she added that CMR would need to reduce the size of its 200ml liquid methanol cartridges to meet airlines’ current rule that restricts carry-on liquid containers to 100ml in volume.

Siobhan Wagner