Solid oxide fuel cell(SOFC) is a promising energy conversion device. It has the advantages of non-pollution

high energy utilization rate

and good fuel adaptability. However

SOFC often needs to be operated under variable load conditions

which leads to the problems of shorten service life and performance degradation.The study of the relationship between the variable load characteristics of SOFC and its operating conditions is helpful to improve the output performance of the stack

extend its service life

and formulate a reasonable control strategy. A 100 W SOFC short stack testing system was developed to experimentally investigate the variable load characteristics of the SOFC stack under multiple operating conditions. The results show that

increasing the operating temperature can reduce the ohmic resistance and total polarization resistance of the fuel cell stack

thereby enhancing the stack's steady-state output performance and dynamic response performance. Increasing the hydrogen flow rate in the medium to high current range can reduce the concentration polarization resistance

thereby effectively enhancing the stack's peak output performance and dynamic response performance. Increasing the air flow rate has a smaller effect on the performance improvement of the stack. Under the constant flow utilization strategy

the response voltage immediately falls within the range of ±5% of the final voltage. By varying the load with constant voltage

the response current can smoothly reach a stable value. Compared with the constant flow strategy and constant current load variation method

the stack shows better dynamic response performance under the constant flow utilization strategy and constant voltage load variation method.