空气流量对空冷燃料电池电堆性能的影响研究

空冷型氢燃料电池采用开放型阴极，具有自增湿、系统简单轻便等特点。为了揭示空气流量对输出性能的影响机制，对自组装的800 W空冷型燃料电池电堆进行了实验测试和数值分析，对比了不同空气风扇转速下电堆输出电压、净功率以及传质传热特性。结果表明：小电流条件下小空气流量可以保持电堆内较高的温度，减少活化损失，实现高净输出功率。然而，大电流条件下，小空气流量将导致电堆温度过高且分布不均匀。利用数值方法对组分和温度分布进行了可视化分析，结果表明低含水量引起的欧姆损失增加是限制输出功率的关键因素，通过提高风扇转速增加空气流量可以保证较好的冷却效果，从而提高含水量，减少欧姆损失。

Influence of air flow rate on the performance of air cooled hydrogen fuel cell stack

The air cooled hydrogen fuel cell adopts an open cathode, which has the characteristics of self-humidification, simple and portable system, etc. However, its performance is not as well as a water cooled fuel cell. It is necessary to reveal the relationship between temperature and water content in the air cooled fuel cell in order to increase the output power. An 800 W air cooled fuel cell stack assembled in the laboratory was tested and analyzed. The voltage-current curve, net power, mass and heat transfer characteristics of the stack under different air fan speeds were compared. The experimental results show that at low currents the low flow rate under slow fan speed can maintain high temperature in the stack to reduce the activation loss of the catalyst, so that the stack could achieve large net output power. While under high current conditions, low flow rate will lead to excessive temperature and decrease the consistency. The distribution of oxygen concentration, water content and temperature in the fuel cell are visualized by numerical method. It is indicated the ohmic loss caused by low water content is the key factor limiting the output power, and by increasing fan speed and increasing the air flow, a better cooling effect can be ensured, thereby increasing the content water volume, reducing ohmic losses.