磷酸鋰鐵電池放電特性及其電路模型分析

Analysis of Discharge Performance of LiFePO4 Battery Based on Electrical Circuit Model

廖乙碩(Yi-Shuo Liao)

指導教授 ： 李坤彥

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2012年)

https://doi.org/10.6342/NTU.2012.02173

摘要

電池的開路電壓以及內電阻對於電池的使用上是重要的評估指標，而磷酸鋰鐵電池的開路電壓以及內電阻在不同的電池容量下有著非線性的變化。為了捕捉這段非線性關係，本文利用等效的電路架構模型來闡述磷酸鋰鐵電池放電時的電壓變化特性，並利用趨近線來擬合電池的開路電壓以及內電阻變化的數學模型。本實驗採用了各種不同條件(如：放電程度、老化程度、受熱程度等)的磷酸鋰鐵電池來做測試，並歸納比較不同條件電池的電路模型特性。另外根據所建立的數學關係式以及電路模型架構，模擬不同條件下的磷酸鋰鐵電池在不同負載電流下的放電行為。最後，本文提出了一套系統來估測電池的充放電程度。

關鍵字

磷酸鋰鐵電池 ； 開路電壓 ； 內電阻 ； 電路架構模型 ； 趨近線擬合 ； 放電行為模擬 ； 充放電程度估測

並列摘要

The open circuit voltage (OCV) and internal resistance of battery cells are important indications for the operation of power systems. The relationships of the OCV and internal resistance between the state of charge (SOC) of a battery are nonlinear. In order to investigate such relationships, this paper uses the equivalent electrical circuit model to characterize the discharge behavior of the LiFePO4 batteries, and also uses the curve fitting method to establish the mathematical functions of the variation of OCV and internal resistance. In this research, various types of batteries (such as cycled, aged, and heated) are introduced into the analysis and comparison. Besides, according to the adopted battery model and the built curve functions, the simulations of the performance of the test batteries at various discharge currents are compared with the experimental data. Finally, a method to estimate the cycling conditions of batteries is proposed in this thesis.

並列關鍵字

LiFePO4 battery ； open circuit voltage (OCV) ； internal resistance ； electrical circuit model ； curve fitting ； simulation of discharge performance ； estimation of cycling condition

參考文獻

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