Tetramer has been awarded a Phase IIB Contract (SC-0006172) to develop new high performance water vapor membranes to improve fuel cell balance of plant efficiency and lower costs. Durability and cost have been identified as the two primary improvement opportunities needed for vibrant commercialization of fuel cell vehicles by the DOE sponsored US Drive Fuel Cell Technical Team, with the humidifier and PEM membrane performance and cost among the key concerns. During Phase II, Tetramer Technologies has developed new water vapor transport (WVT) membranes which significantly outperformed the current perfluorosulfonic acid (PFSA-Nafion) and other WVT membrane competitors at ~50% lower projected cost. Optimization of this new technology during Phase IIB, which will involve improved block copolymers, support structures, and IEC improvements will positively affect the fuel cell balance of plant efficiency and lower costs.
These new polymer structures also showed significantly greater chemical stability at the higher (120oC) cathode inlet temperatures required by fuel cell OEM’s. This lack of chemical stability in conventional PSFA membranes has caused >60% reduction of water vapor performance at 85oC cathode inlet temperatures. Engineering an automotive fuel cell system to compensate for such significant losses would be complicated and expensive (in addition to the high cost of the PFSA WVT polymer), since a larger humidifier would have to be built to compensate for this WVT variation. This variation could also affect the durability and cost of the proton exchange membrane (PEM) stack.
In addition to the power optimization, lower cost, and lower weight impacts afforded by a WVT system for fuel cell vehicles, these membranes are excellent enthalpy candidates for the high potential energy savings (~ 40%) achieved by conditioning air for the large HVAC market which currently uses billions of BTUs.
The primary focus of the proposed Phase IIB research will be to take advantage of the new technologies discovered during the delayed Phase II development to increase the commercial value proposition by further lowering manufacturing cost, optimizing polymer molecular architecture, extending durability, and performance (which will further decrease fuel cell engine cost, durability, and weight). The durability target will be 10% performance loss over a 500 hour accelerated test and 5000 hours over the operating life of the vehicle.