Scientists from University College London (UCL) and Imperial College London believe that they can make fuel cells that are 30 per cent cheaper than existing products by replacing the heavy steel plates used between cells with printed circuit boards (PCBs).
Bipolar steel plates have traditionally acted as current conductors between individual cells, enabling fuel stacks to produce a higher overall power output.
Dr Daniel Brett of UCL’s Department of Chemical Engineering told The Engineer: ‘We have a completely new way of putting the fuel cell together.’
Traditionally, fuel-cell stacks have comprised several bipolar steel plates, each separated by a membrane electrode assembly (MEA).
The approach being developed by the London researchers would incorporate the MEA into the PCBs. ‘We put together a hot press to form this monolith that looks, touches, feels and has the same weight as the PCBs found in the motherboard of your home computer,’ said Brett.
He added that the fuel cells would be lighter than existing technologies because PCBs weigh less than the steel plates currently used. Brett also said they will have power densities equal to or better than existing fuel cells.
‘The key with PCB technology is that it’s so highly engineered,’ said Brett. ‘We were staggered by how cheap these things are, particularly if you go to the Far East. The cost isn’t the only thing; it’s the capacity.’
Fuel cells made in this way could also be more reliable. ‘A normal fuel cell is like a load of different links in a chain, and if one of those fuel cells fails the entire fuel cell fails,’ said Brett. ‘If one of our layers fails, the rest of the system carries on working because the current doesn’t pass in series through the entire thickness of the cell.
‘What happens here is the current flows laterally, which means it has very good tolerance, so one of these layers could fail and the system wouldn’t go down.’
The team is hoping to develop fuel cells for three applications: portable powered electronics; combined heat and power plants; and vehicles.
The team has so far demonstrated the fuel cell in the lab operating at a few Watts, which is enough to power a portable electronic device. The scientists are aiming to demonstrate a combined heat and power fuel cell operating at ~1KW by the end of 2012 and a car fuel-cell prototype by the end of 2013.
The Carbon Trust has allocated £500,000 to the project to help develop this technology.