Proton power

Almost all the major car producers have now dipped their toes into the small pool of available fuel cell technologies. Recent concept cars reveal an industry creeping ever closer to commercial production of a fuel cell driven car. But which manufacturer will actually take the plunge is not clear.

In the last month alone Nissan, Volkswagen, and General Motors revealed the progress of their fuel cell development. All of them differ in form, but under the bonnet many have one thing in common; Ballard Power Systems’ Fuel Cells.

Ben Wiens, a former Ballard researcher, and now an energy consultant, gave Design Engineering his views on where the automotive industry stands with fuel cells.

When will it happen?

‘It’s my guess that by 2020 most new vehicles will be powered by fuel cells. Which of the many fuel cells and fuels proposed will emerge dominant is still very unclear. This uncertainty will no doubt result in great upheavals in the vehicle industry.

In the 1970s, visions of a world wide hydrogen fuelled economy produced by nuclear power became popular. Nuclear power, however, is not popular today and much of the hydrogen in the next 20 years will be produced from fossil fuels.’

What has changed?

‘This situation changed considerably around 1998 with advancements in fuel cells that convert hydrocarbon fuels directly to electricity, for example the direct methanol fuel cell (DMFC) and solid oxide fuel cell (SOFC). If fuel cells do not require hydrogen gas then there are big advantages in using a liquid renewable fuel in place of hydrogen. In the year 2000 ethanol is emerging as this renewable fuel of choice. There is increasing concern about the costs of producing, distributing, and storing hydrogen.’

All fuel cells consist of two electrodes (an anode and a cathode) separated by an electrolyte. In most systems hydrogen is fed to the anode, and ionised into a proton and an electron. The proton makes its way to the cathode through the electrolyte, while the electron passes through whatever the cell is powering, and back again. At the cathode, the protons and electrons react with oxygen from the air to make the only waste product: water.

Current state of play?

‘Many companies are now working on different versions of DMFC and recently work is starting on direct ethanol fuel cells (DEFC) for vehicles. These would operate at low temperatures; making them perfect for intermittent vehicle use. A disadvantage of the SOFC is that it does not produce power at ambient temperatures and needs warm-up time. In spite of this, several SOFCs are being developed for vehicles.

Some medium temperature SOFCs are being developed but the advantage of high temperature SOFC is that they can be adapted to run on a wide variety of liquid and gaseous fuels. Some engineers believe the start-up time could be reduced to as little as two minutes. Hybrid versions with ‘supercapacitor’ batteries to power the vehicle during the start-up time might be very practical.’

Who lead the way?

‘Companies in this field have vastly different approaches to development. Until recently Ballard in Canada focused exclusively on developing hydrogen polymer electrolyte fuel cells (PEFC). They have spent nearly 15 years in development and are just now gearing up for mass production.

ZeTek Power in the UK are taking the opposite approach and claim they are fuel cell neutral and hope to develop many different fuel cell technologies in the future. Presently they are focusing on a hydrogen fuelled alkaline fuel cell (AFC) that has a proven track record. Instead of spending years in development, they have been producing reasonably inexpensive mass produced fuel cells for some time.’

‘We have developed a modular alkaline fuel cell that can be efficiently manufactured in large volumes. The ZeTek alkaline fuel cell is a reliable, pollution free, quiet and more cost efficient than existing fuel cell technologies.’ says chief executive Nicholas Abson.

AFC technology requires two porous electrodes, separated by a potassium hydroxide electrolyte. Unlike PEM cells, they do not rely on platinum catalysts.

The best strategy?

‘With so many uncertainties in this field, keeping fingers in many pies might prove to be a good strategy. It appears that many major automakers are not pinning their hopes on just one fuel cell technology either.’