40,000 h Record for SOFC Stacks

Successful endurance test under real operating conditions

Endurance test of a fuel cell stack with high-temperature fuel cell (SOFC) to demonstrate the feasibility of long-life stationary systems.

In order to prove the long-term stability, an endurance test was started in August 2008 with a high-temperature fuel cell (SOFC) stack developed at the JÜLICH Research Center. In this test, the stack is operated in a furnace under constant conditions at 700°C ambient temperature with hydrogen and air and a current load of 500 mA/cm².

After now more than four and a half years of operation (40,000 hours), the performance has decreased by approx. 37% due to operational aging processes. This corresponds to an aging rate of 0.9% per 1,000 hours. Although the initial target of 20% power reduction in 40,000 hours required for commercialization has not yet been fully achieved, it has been shown that such operating times are fundamentally feasible with the materials used. Tests with further improved coatings show aging rates of approx. 0.15% per 1,000 hours, but the operating times achieved here are only 10,000 hours.

In order to prove the performance and aging stability, an endurance test was started in August 2010 with an energy system with direct methanol fuel cell (DMFC) developed and created in IEK-3. The system is loaded under realistic application conditions of a horizontal order picker in three-shift operation.

After more than one year of operation (10,000 hours), the achievable cell voltage has dropped by 80 - 130 mV due to operational aging processes. In the worst operating case at 100 mA/cm², this corresponds to an aging rate of 2.5 % per 1,000 hours. This doubled the target of 5,000 operating hours required for commercialization.