Volkswagen Research has developed a new and innovative type of high temperature fuel cell (HTFC) that means an affordable fuel cell-powered vehicle suitable for everyday use could be available as early as 2020.
This breakthrough is made possible thanks to a new, high temperature membrane and electrodes, which enable significantly more compact, cheaper and more efficient fuel cell systems. In the HTFC protons are exchanged via phosphoric acid. The acid has good electrolyte prperties, similar to water, but has a higher boiling point permitting higher temperature operation and simplifies the water management and humidification required in most PEM cells. On a special screen printing machine, the new electrodes, made of carbon fiber cloth are coated with a new type of paste, which makes the electrode impermeable to water and preventing dilution of the phosphoric acid.
LTFC systems are operated at a membrane temperature of approximately 80 degrees Celsius, or about 176 degrees Fahrenheit. If the temperature greatly exceeds this value, fuel cell performance breaks down and irreparable damage is done to the cell.
The high temperature, thinner membrane developed by Volkswagen can, in combination with newly-designed electrodes operates at temperatures of up to 120 degrees Celsius, or about 248 Fahrenheit, without additional humidification. Thus a distinctly simpler cooling and water management system is possible, significantly reducing the cost and the requirements for space and weight.
After additional improvements the first research vehicles are expected by 2010 and by about 2010 the first full production models could appear.