Fundamental Research on Increasing Output Power Density of Phosphoric Acid Fuel Cel

磷酸燃料电池在高输出功率运行时性能不稳定。本研究的目的在于解释这些现象，并开发出提高输出功率密度的新方法。主要研究结果如下：(1)在高输出功率密度的情况下，采用强防潮的阴极催化剂层，在运行初期会出现不稳定现象。操作前需要将磷酸渗透到催化剂层中。(2)为了加速酸的渗透，试验了真空浸渍、超声波渗透、添加醇渗透、电毛细渗透和冷凝酸渗透等5种方法。前两种使用机械外力的方法效果不太好，而后三种使用毛细力的方法则有效且实用。(3)不稳定现象具有氧耗散电极区域传播的特征。使用贫氧气体进行酸渗透诊断试验是可能的。(4)负荷变化或启停工况下酸浓度的周期性变化影响电池性能衰减。

Unstable performance of phosphoric acid fuel cells was found at high output power operation. Purposes of this research are to explicate these phenomena and to develop new methods for increasing the output power density. Main rsults are as follows,(1) Unstable phenomena occur early in operation of high output power density when a strong wet-proofed catalyst layr of a cathode is used. It is neccessary to penetrate phosphoric acid into the catalyst layr before operation.(2) In order to accelerate the penetration of the acid, five methods are tested such as vacuum impregnation, super-sonic penetration, alcohol-added penetration, electric capillary penetration and condenced acid penetration. Former two methods using external mechanical force are not so effective, whereas the latter three methods related to capillary force are effective and practical.(3) Unstable phenomena have features of propagation of oxgen dissipated electrode area. Diagnostic tests for acid penetration are possible by using oxgen poor gas.(4) Periodic change of acid concentration assuming load change or start-stop operation affect cell performance decay.