New material promises fuel cell cost breakthrough
28 November 2012
A new material for coating fuel cell bipolar plates is set to change the economics for fuel cells by significantly reducing manufacturing costs.
The cost for bipolar plates is currently one of the main obstacles to widespread commercialisation of fuel cell technology. Ceramic MaxPhase from Swedish company Impact Coatings provides an alternative to coating the metal bipolar plates with gold, the current method used to prevent corrosion of the plates.
“Cost-effective production of bipolar plates is one of the main elements needed for making fuel cells viable in the volume market. Using a material that is far less costly than gold, but has similar physical properties, will help reduce the cost for fuel cell bi-polar plates. We can today meet a coating cost of $5 per kW and expect to reach below the US Department of Energy 2017 target of $1 per kW, significantly ahead of time,” says Henrik Ljungcrantz, CEO at Impact Coatings.
Bipolar plates are used as anodes and cathodes in fuel cells, connecting several cells into a stack for the desired voltage. Because of the highly aggressive environment inside the fuel cell, the plates are prone to corrosion. Graphite, which is a corrosion-resistant material, has been used, but produces bipolar plates that are bulky and heavy. Graphite plates are also difficult to manufacture at low cost and in high volume. They are now gradually replaced by stainless steel bipolar plates, with a thin protective coating to prevent corrosion.
With less bulk than graphite and significantly lower cost than gold coated plates, metal plates with Ceramic MaxPhase is a solution that can meet the US Department of Energy’s targets for cost as well as technical performance.
Ceramic MaxPhase is a corrosion-resistant, electrically conductive ceramic coating that is applied by physical vapour deposition. The material has been qualified for use in proton exchange membrane fuel cells (PEMFC) as well as direct-methanol fuel cells (DMFC) in tests exceeding 2500 hours. The bipolar plates of stainless steel coated with Ceramic MaxPhase showed equivalent stack performance to gold plated bipolar plates during the tests.
The process and the material are now commercially available. A range of deposition systems for volume production is manufactured by Impact Coatings and a coating service is carried out at the company’s premises in Linköping in south-central Sweden.
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