質子交換膜燃料電池結構之分析與最佳化設計

Abstract

本文研究質子交換膜燃料電池之結構分析與最佳化設計。目的為使用有限元素法分析燃料電池在穩態的運作下其結構行為。首先，提出一新型之質子交換膜燃料電池，並發展一參數化繪圖程式以自動繪製燃料電池所有元件之實體模型，將模型匯入至有限元素分析軟體建立網格模型。此分析模型之負載包括化學反應產生之熱、碳板內冷卻水效應與施加於端板上之鎖合力，計算出燃料電池之溫度分布與熱變形。單電池與多電池組燃料電池均進行此分析。並且使用紅外線熱影像儀量測燃料電池表面之溫度分布，將分析結果與量測結果做驗證，溫度分布趨勢是相同且接近的。根據分析結果，熱效應是造成燃料電池各元件產生較高應力之主因且會造成碳板破裂。最後，提出一整合型最佳化設計程式，此程式整合電腦輔助繪圖軟體、有限元素分析軟體及數值搜尋，以找出滿足設計限制條件且提高碳板結構強度之最佳化設計。從分析與最佳設計之結果顯示，本文之結構分析與最佳化設計方法可有效率地應用於燃料電池之分析與設計。

This paper studies the structural analysis and optimum design of a proton exchange membrane (PEM) fuel cell stack. The aim of this study is to recognize the structural behaviors of PEM fuel cell under operation stage at steady state by using finite element analysis (FEA). First, the PEM fuel cell models are constructed with whole components. The models for FEA are generated by a CAD software with a parametric program, and then are imported into FEA software to generate meshed model. Next, with given thermal and structural loadings, a series of finite element analyses are executed to analyze the thermal and structural behaviors of PEM fuel cell. A meshed model of a single cell is generated and analyzed at the beginning. The boundary conditions are applied into the meshed model, such as heat generation of chemical reaction, force convection of cooling water, and assembly pressure on the end plate, to obtain the behaviors of single cell. Besides, the analyses of multiple-cell short stack are executed as well. Finally, temperature measurement method of infrared (IR) thermography is applied to record the temperature distribution of exterior surfaces in a PEM fuel cell and verify the simulation results. It shows that the analysis results are generally close to the experiment results. The thermal effect is identified as the main factor for the high stresses and will cause the failure of the fuel cell components, especially for carbon plates. Also, an optimum design procedure is performed to obtain a better carbon plate structure design satisfying the structural safety requirement.