Economical use of PEM fuel cell power for stationary applications demands a lifetime of the fuel cells of at least 5 years, or more than 40,000 hours of continuous operation. This, in contrast to the large scale application for automotive use, which has focused PEM research on low cost production techniques with practical lifetimes of the fuel cells of 5,000 hours.
The lifetime of the 40,000 hours will be proven by extrapolation of long duration data. The initial phase of the project consists of establishing the dominant degradation mechanisms of the state-of-the-art MEA and setting up the initial framework for the theoretical model.
Challenges / Issues addressed
The PEM fuel cell consists of several alternatingly stacked components, such as membrane-electrode-assemblies (MEAs) and bipolar plates, pressed together by a housing. The MEA consists of subcomponents like gas diffusion layers, catalyst layers and a thin membrane, separating reactant gases. The bipolar plate is a carbon composite, electrically connecting neighbour cells and distributing reactant gases over the MEA electro-active area.
All these components face harsh conditions imposing chemical and mechanical stress that during operation, changes the structure and composition, thereby lowering the power output of the fuel cell and limiting the lifetime. Also operating conditions like temperature, gas humidification and gas feed play a role in the fuel cell lifetime.
Within the project it will be attempted to determine the dominant degradation mechanisms in a real life stationary PEM Power Plant. Subsequently these components and operational parameters need optimising to reach the goal of 40,000 hours of continuous operation.
An iterative work plan is presented. The work plan of the project in time:
1. Duration experiments in a real-life stationary fuel cell plant from Nedstack and at SINTEF and SolviCore at lab-scale with stacks composed of the state-of-the art reference materials, like the membrane as provided by Solvay Specialty Polymers Italy.
2. Model improvement and analysis of on-line and off-line measurements by JRC. Post-mortem analysis on stacks returning from durability experiments yields data of the degradation processes. Based on these results improved MEA’s and stack components will be produced as well as a fine tuned model.
3. A second series of duration experiments is started and SINTEF will also perform accelerated lifetime tests.
4. The final period starts with the most promising stacks. From the model and from data extrapolation the lifetime can be predicted.
Expected socio and economic impact
One of the main aims of the FCH-JU is: “... placing Europe at the forefront of fuel cell and hydrogen technologies worldwide and enabling the market breakthrough of fuel cell and hydrogen technologies, …” To reach this goal, it is essential that the durability of the stack and its components is significantly improved and at a well mature and cost competitive level. STAYERS will contribute to this by developing a stationary PEMFC stack with 40,000 hours lifetime.
The project will also strengthen the knowledge about degradation mechanisms in PEM fuel cells. At the same time STAYERS will create business opportunities, not only for its partners, but also for the whole of the fuel cell community. Commercial prospects for PEM FC-generators are very promising if a guaranteed stack lifetime of 5 years can be given. Society will benefit by less CO2-emission, pollution-free, low noise
The fuel cell principle
A fuel cell generates electricity from hydrogen and air. A catalyst enables very efficient chemical conversion of hydrogen (H2) and oxygen (O2) from the air into water (H2O). It is a combustion without fire or moving parts. A fuel cell generates electricity without noise, fine particle emissions, or friction and wear. This solid state technology compares to a diesel generator like an iPod to a turntable.