利用電化學法建立鋰電池模組預測模型分析交流阻抗頻譜以及並聯之行為與電池安全性設計

Abstract

近年來因為化石燃料的短缺，人們開始研究將鋰離子電池應用在電動車上，以大型鋰電池組提供電動車所需的能量來源。但大型電池組的實驗通常費時與耗去大量金錢，因此若藉由模擬的方式進行電池組效能的預測與評估，將能降低實驗所消耗的成本。本論文將針對電動車中電池組設計待解的問題做模擬與探討，以期對電動車的發展做出貢獻。本論文將研究五類問題，分別為：電池組放電效能預測、電池組溫度分布預測、電池組壽命預測、電池組安全設計、電池組狀態檢測。 針對電池組放電效能與溫度分布之研究，我們與工業技術研究院合作取得了十三串兩並共二十六顆電池之電池組實驗數據。利用我們所發展的電化學模型進行模擬，電池組放電曲線與溫度變化的實驗與模擬結果相當吻合。電池組壽命預測部分則以單顆電池壽命的實驗與模擬結果吻合，進而將預測方法應用到電池組中。 電池組的安全性設計為添加工研院所研發之材料STOBA至鋰電池中，再對電池進行穿刺試驗檢驗電池安全性，實驗結果顯示STOBA能夠有效的保護鋰電池使其不產生熱爆走之現象。接著對STOBA進行探討嘗試了解其作用機制，並利用電化學模型模擬添加STOBA後電池受穿刺試驗過程之變化。 最後是電池狀態的檢測，利用非破壞性的檢測方法：量測鋰電池阻抗頻譜，分析阻抗頻譜進而獲得電池的老化程度等等資訊。

Recent years, the research on the electric vehicle is increasing due to the shortage of fossil fuel. Lithium battery, which has high power density and enrgy, is a well choice as power source for electric vehicle. However, the exmperiment for studying lithium battery pack is expensive and time-consuming. Therefore, we try to analyze and predict the efficiency of battery pack by simulation to decrease the experimental cost. There are five groups of important problems, which are prediction of battery pack discharge efficiency, prediction of battery pack temperature distribution, prediction of battery pack cycle life, safety of battery pack design and detection of battery pack, about the developement of electric vehicle will be discuss in this thesis. We have a cooperation with ITRI which offer us experimental data about battery pack to study battery pack discharge efficiency, battery pack temperature distribution and prediction of battery pack cycle life. By the electrochemical model we built, the simulation result of battery pack’s discharge curve and temperature variation has a well agreement with experimental data. ITRI developes a kind of material called STOBA, which is added in lithium battery to prevent thermal runaway during nail penetration test. According to the nail penetration experimental result, the battery with STOBA will not burn and explode. Then, we try to figure out the mechanics of STOBA and simulate the process during nail penetration test by electrochemical model. We use the nondestructive testing which is impedance spectrum measurement to detect the status of battery. By analyze the impedance spectrum, we will obtain the information about battery. It is very helpful on the battery detection.