鋰離子電池組之老化延緩與狀態快速估算

Reduction of Capacity Degradation and Rapid State Estimation for Lithium-ion Battery Packs

蔡明儒(Ming-Ru Tsai)

指導教授 ： 陳國慶

國立臺灣大學/工學院/應用力學研究所/碩士(2022年)

https://doi.org/10.6342/NTU202202650

摘要

準確地估計電池狀態與延緩電池老化，對於電池組的使用壽命與安全性至關重要。本論文將會分為兩大主軸，分別探討如何延緩並聯電池組的老化以及快速檢測單電池與串聯電池組的狀態。
　　並聯電池組的衰退多半被歸咎於電流分佈的不平衡，為了制定並聯電池組的延緩老化策略，將會對其運作原理與老化機制做深入的剖析。本論文透過限制使用區間的方式，使得電池組在電流穩定的區段進行循環，進而達到延緩老化的目的。為了提高分析的效率與減少繁瑣的實驗流程，也會提出一個數學模型來模擬電池組在實際運行時的狀態。
　　串聯電池組的衰退多半被歸咎於是電池狀態的不一致。本論文提出以多項式函數來估算電池狀態。首先，會將全新電池的充電電壓曲線擬合為多項式函數，並透過平移與縮放求得不同電流值與健康狀態下的充電電壓曲線。由於電池內阻隨著充電電流與健康狀態不同而有差異，因此以脈衝測試確定函數在不同條件下的平移量。經由實驗證實廣義的充電電壓曲線可以被應用於檢測電池狀態。

關鍵字

鋰離子電池 ； 串並聯電池組 ； 電池內阻 ； 狀態檢測 ； 循環壽命

並列摘要

Accurately estimating the state of batteries is crucial to a battery pack’s remaining life and safety. This paper will explore the strategy of lifespan extension and state detection for lithium-ion battery packs.
　The degradation of the battery packs in parallel is mostly attributed to the unbalanced current distribution. To formulate the strategy of lifespan extension for battery packs in parallel, this paper will analyze the current distribution and aging behavior. For the purpose of reducing the capacity degradation, the lower voltage limit will be increased. Besides, to efficiently analyze the battery packs in parallel, a mathematical model is proposed.
　The degradation of the battery packs in series is mostly attributed to the difference between the state of batteries. A method for estimating the state of charge and the state of health of a battery is proposed in this paper. First, the charge voltage curve (CVC) of a new battery, is numerically fitting by a polynomial function. Second, because the internal resistance of a battery varies with the charging current and the SoH, the DC pulse test is adopted to determine the amount of the translation and scaling of the reference CVC under different conditions. The results demonstrate that the generalized CVC can be applied to estimate the states of batteries.

並列關鍵字

lithium-ion battery ； battery pack ； internal resistance ； state detection ； cycle life

參考文獻

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