Speaker
Description
Renewable energy and hydrogen energy are increasingly being utilized to address climate change. To utilize hydrogen energy, applications such as fuel cell-based mobility and power generation need to be expanded. Hydrogen electric vehicles, a representative application of fuel cells, were commercialized by Hyundai and Toyota in 2013 and 2014, but they are facing difficulties in expanding the market. In order to expand the market for hydrogen electric vehicles, the durability and price of the fuel cell stack must be resolved. While fundamental improvements need to be made in MEA manufacturing processes and materials, driving logic and systemic approaches can maximize the lifespan of stacks at current technology levels. Several factors contribute to the shortened lifetime of the stack, including frequent load fluctuations that cause the MEA catalyst layer to degrade. In this study, we conducted experiments on how to maximize the lifetime of the stack in a hydrogen electric vehicle design in which the secondary battery is responsible for load fluctuations and the fuel cell is responsible for only the baseload. First, the current fluctuation of the HEV stack was obtained by applying the US06 cycle, one of the standard driving cycles, to the Simulink-based HEV model provided by Mathworks. We calculated the average current from the time-averaged output of the entire power generation of the cycle and assumed a baseload setting for the stack. Two 5-cell, 200 cm2 reaction area stacks were built, one with the original load variation and one with the baseload constant current operation for 400 consecutive hours. The performance change was measured every 100 hours, and finally CI(current interrupt) and EIS(electrochemical impedance spectroscopy) experiments were performed to analyze the durability characteristics. The performance decreased by 1.35% under constant current operation, while it decreased by 16.52% under load variation. After 400 hours of load variation, both activation loss resistance and electrical resistance losses increased more significantly than in constant current operation.
References
Zhao, J., & Li, X. (2019). A review of polymer electrolyte membrane fuel cell durability for vehicular applications: Degradation modes and experimental techniques. Energy Conversion and Management, 199(June 2019), 112022. https://doi.org/10.1016/j.enconman.2019.112022
| Keywords | Hydrogen Electric Vehicles, Polymer Electrolyte Fuel Cells, Durability, Accelerated Life Tests |
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