June 2010

Bac2 announces improved material for fuel cell bipolar plates

Southampton, UK, June 22, 2010: Bac2, the cleantech materials and components company, has announced an improved version of its ElectroPhen ® material for the production of moulded fuel cell bipolar plates. Called EP1109, the new material was originally developed for operation in direct methanol fuel cells. However, tests in low temperature proton exchange membrane (PEM) fuel cells have indicated that using EP1109 results in higher output voltages from individual cells and that the steady-state cell voltage is maintained for longer, both of which are desirable characteristics.

Bipolar plates contain channels through which fuel, air and water vapour flow and they need to be electrically conductive to pass the current generated by the cells. Bipolar plates can be made from conductive materials such as graphite or metal. Graphite plates are not economical because they need to be individually machined to create the flow channels. Metal plates suffer from surface corrosion due to the acidic environment in a fuel cell stack. These problems are overcome with ElectroPhen®, which is a chemically inert, electrically conductive, thermoset composite material made using Bac2’s patented polymer technology. It can be compression moulded and cured at low temperature, enabling plates to be produced quickly and economically in any quantity. Compared with other composite materials, ElectroPhen® can achieve the required conductivity for fuel cell plates with a lower loading of graphite. This means that the flow properties of ElectroPhen® moulding compounds are superior, leading to a better mould fill and tighter dimensional tolerance.

For prototyping purposes, Bac2 can supply either moulded blank ElectroPhen® plates or plates machined by Bac2 to the customers’ designs, prior to producing mould tools for high volume production. Standard blank plates are available in sizes from 60mm x 40mm up to 300mm x 200mm. The mechanical strength of ElectroPhen® allows plates of 1mm thickness or less to be produced, enabling production of compact fuel cell stacks.