- 學位論文
電動車電池模組之可靠度分析與設計調整
Reliability Analysis and Design Adjustment of Battery Module for Electric Vehicles
摘要
電池為電動車的動力來源，為避免電動車行駛時電池突然失效所帶來的風險，電池模組的可靠度研究顯得相當重要。針對一穩定行車時之車用電池模組，本研究先以有限元素分析獲得模組內各單電池的溫度，藉以評估各單電池電量衰退情形；而後，將電池模組視為由單電池組成的系統，同時考量單電池電量衰退的不確定性，將模組視為一具有多個不同可能狀態的系統，透過通用生成函數，評估電池模組的可靠度。本研究並依以上所建構之電池模組可靠度分析與評估模型，探討一電池模組內之單電池數目增減及其串並聯配置調整對模組可靠度之影響，並藉以評估電池模組設計調整之可能。本研究結果顯示，除一味增加單電池數量 外，模組內單電池串並聯配置的適當調整，對模組可靠度的增加有時還較為有用，尤其在輕量化的考量下；亦即，在增加電池模組內之單電池數目時，也不宜忽略電池串並聯結構之配置調整。電動車之電池模組設計有各種不同考量依據，本研究所提出之可靠度分析與評估模型除能有效評估電池模組可靠度外，也可平行作為既有電池模組設計調整之參考。
並列摘要
Electric vehicles (EVs) are powered by battery modules, especially li-ion battery modules in recent years. If battery modules fail unexpectedly when an EV cruises on the road, it may bring danger to drivers and/or pedestrians. Therefore, the reliability analysis of battery module is very important. For a battery module in operation, the temperature of each battery cell within it can be obtained by finite element analysis. The capacity fading of each cell can be estimated accordingly. If uncertainties of capacity fading of battery cells are taken into consideration, a system reliability issue arises in which the battery module is regarded as a system consisting of battery cells. In this study, a universal generating function (UGF) technique is used for the reliability analysis of li-ion battery module used in EVs. To what extents redundant cells and the series/parallel configuration of cells affect the reliability of battery module are investigated in particular. Design adjustment of battery module in its configuration can be proposed based on result of the analysis. Through case study, it is found in this thesis that, to improve the reliability of a battery module, adjustment of series/parallel configuration of cells is sometimes better than just adding redundant cells to it. The finding is especially important when minimum-weight design of a vehicle is considered. It is argued that the proposed analytical algorithm can be used for design adjustment of battery module of EVs in which the major design concern may not be reliability.