Why can very high temperatures shorten the lifetime of fuel cell components?
The proton exchange membrane is one of the most advanced fuel cell designs. Hydrogen gas under pressure is forced through a catalyst, typically made of platinum, on the anode (negative) side of the fuel cell. At this catalyst, electrons are stripped from the hydrogen atoms and carried by an external electric circuit to the cathode (positive) side. The positively charged hydrogen ions (protons) then pass through the proton exchange membrane to the catalyst on the cathode side, where they react with oxygen and the electrons from the electric circuit to form water vapour (H2O) and heat. The electric circuit is used to do work, such as power a motor.
While very high temperatures can improve the activity of catalysts and fuels within a fuel cell, they can also negatively impact the system's longevity.
Operating at temperatures significantly outside of a fuel cell's designed range can reduce the functional lifetime of several critical components, including:
- Electrodes: High heat can degrade the materials necessary for consistent electrochemical reactions.1
- Construction materials and joints: Excessive heat, particularly when combined with frequent heating and cooling cycles, can stress structural seams and joints, potentially leading to failure.23
- Support systems: Components such as blowers and sensors may experience accelerated wear or degradation under adverse thermal conditions.14
Furthermore, in specific types like alkaline fuel cells, the combination of high temperatures and strong electrolytes can increase the risk of the electrolyte attacking structural materials. Consequently, maintaining a stable operating-temperature design range is essential to balancing performance with the long-term durability of the system.312