5kW質子交換膜燃料電池堆以二極體串並聯之氣體與水管理系統研究

Abstract

本研究為開發一氣體與水管理系統，藉以操作5 kW質子交換膜燃料電池堆(Ballard 1310)，使燃料電池的使用效率提升。原設計之各子系統中，包含過多外接感測元件造成管路過長，而出現熱耗散及不均勻的現象，使供應之氣體溫度下降；藉由減少各系統中的感測元件及管路的縮短設計，能有效提升供應氣體之溫度，提升燃料電池堆的性能。為了使單一5 kW燃料電池堆之效能達最佳化，本研究亦針對其他關鍵參數進行實驗分析，其中氫氣及空氣的相對濕度對於電池堆性能表現有很大的影響，對於輸入氣體進行適當的加濕是很重要的，此外，分析氫氣於各負載下的消耗情形，有助於設計氫氣之供應流量及氫氣的再循環機制，而提升氫氣的使用效率，於高負載下，本研究亦探討單電池堆在有無氫氣循環回收狀況下，整體發電效率之差異。5 kW燃料電池堆在控制系統的安全監控下，能於高效能之狀況下穩定操作，並做為未來高瓦數之燃料電池堆開發之基礎，而為使總輸出功率可達10 kW，另一5 kW燃料電池堆系統將與原系統做串並聯組裝，且因其效能輸出幾乎一致，兩電池堆將可直接以二極體作電路上的串並聯而有長時間且穩定之高功率輸出。

In this study, fuel, oxidant supply and cooling systems with a microcontroller unit (MCU) were developed in a compact design to fit two 5 kW proton exchange membrane fuel cell (PEMFC) stacks (Ballard 1310). The original design of the subsystems, which had a longer pipeline and excessive control sensors, caused a large pressure drop and high power consumption. However, with an MCU, the fuel consumption and humidity can be effectively controlled within a proper purge period. Additionally, this study includes stack performances under different hydrogen recycling modes and the direct electrical coupling of two similar 5 kW stacks with diodes to obtain a higher power output. The result showed that the efficiency of the 5 kW stack is 43.46 % with a purge period of 2 minutes with hydrogen recycling and that the hydrogen utilization rate, μf, is 66.31 %. In addition, the maximum power output of the twin-coupled module (a power module with two stacks in electrical cascade/parallel arrangement) is 9.52 kW.