Improvements in Conductive Polymer Boost Fuel Cell Performance; Exceed DOE Conductivity Targets for Automotive Applications
|Stack with Bac2 Electrophen plates. Click to enlarge.|
Bac2 Conductive Composites, a UK-based start-up fuel-cell materials company, has announced substantial conductivity improvements for its patented ElectroPhen conductive polymer. Independent tests have shown that the latest version of the thermoset material, which uses a new curing agent, demonstrates an improvement in in-plane electrical conductivity to nearly 500 siemens per centimeter.
The material now exceeds the US Department of Energy conductivity target of 200 siemens per centimeter for such materials used to make bipolar plates for fuel cell applications. The target primarily relates to fuel cells for use in automotive applications.
ElectroPhen is an electrically conductive polymer and polymer composite that can be formed at room temperature. Other plastics are electrically insulating but the base polymer of ElectroPhen is unique because conducting pathways are produced in-situ during the polymerization reaction. The resulting conductivity can be further enhanced by adding conductive fillers to produce ElectroPhen polymer composites.
Bipolar plates and end plates make up to 70% of the weight and 30% of the cost of a typical Polymer Electrolyte Membrane (PEM) fuel cell stack. Making them from ElectroPhen would deliver substantial cost savings without compromising performance.
ElectroPhen’s raw state conductivity is in the order of 109 more conductive than commonly used resin binders, which means that no post-processing, such as extreme temperature or surface machining, are required. This makes ElectroPhen plates easy and economical to produce in the high volumes anticipated for full-scale deployment of fuel cells.
Furthermore, the ratio of ElectroPhen to graphite resin makes for a tougher plate and further modification with plasticizers, reinforcers, and conductive fillers enable the composition to be fine-tuned for specific applications and customer requirements.
Other physical characteristics of ElectroPhen are its thermal stability, resilience to temperature and inertness towards fuel cell catalysts and membranes. This means that fuel cell stack manufacturers can safely explore the use of more economical MEA (membrane-electrode assembly) materials that may yield greater efficiency with higher temperatures at the reaction surface.
In May 2006, Bac2 secured £500,000 (US$966,000) of seed funding in a round led by London Seed Capital in conjunction with the London Business Angel Network and the newly raised LBA EIS Tracker Fund III. Further angel investors were introduced to Bac2 by South East Capital Alliance (SECA), managed by Finance South East, Wessex Ventures, James Cowper Chartered Accountants and the University of Southampton Alumni Fund.
This investment money was in addition to DTI grant funding of £240,000 (US$463,000) awarded to a six member consortium, lead by Bac2, to optimize the ElectroPhen material for use in fuel cell components.