磷酸鋰鐵電池在不同老化情況下之電性與電化學關係探討

Abstract

人類生活極度仰賴石油，但因地球石油儲量有限，人類開始重視綠色經濟並致力開發其他綠色能源，電動車與電動相關載具開始取代傳統石油消耗機械趨勢已然確立。磷酸鋰鐵電池為一種具有高功率、高循環數、高容量、高安全性等優點的二次電池，廣泛運用於攜帶式電子載具、電動車、太陽能儲能裝置等等。因此，研究磷酸鋰鐵電池安全性與健康程度更顯重要。 本論文將電容量10Ah、額定電壓3.3V的磷酸鋰鐵電池在不同老化條件下放電(如：不同環境溫度、不同負載電流、不同充放電循環等)，直到電池達到截止電壓2V，並在放電過程中使用Virtual Bench 連接電腦人機介面LabVIEW程式即時紀錄電池放電電壓。電池達到目標之老化程度後，對不同老化情況之電池進行電性分析，電性分析完成後將電池拆解並做電化學SEM、XRD及FT-IR檢測，歸納不同老化狀態下的電池電性與電化學特性。

Human life depends on fossils in past decades due to the advances in industries and engineering. Because the amount of fuels is limited, people have begun to pay attention to green economy and been committed to developing alternative energy. Electric vehicles and electric portable devices became a trend and started to replace the traditional machines with oil consumption. Lithium iron phosphate (LiFePO4) battery is a secondary battery with advantages of high power, cycle number, capacity, and safety. It’s widely used in portable electronic devices, electric vehicles, and solar energy storage. Therefore, the study about safety and health of LiFePO4 batteries is extremely important. In this paper, LiFePO4 batteries with capacity of 10Ah and nominal voltage of 3.3V were discharged under different aging conditions (such as different experimental temperature, C-rate, and charge/discharge cycles) until batteries reached cut-off voltage of 2.0V. The electrical data was collected by Virtual Bench and recorded by LabVIEW program in the computer. After LiFePO4 batteries reached the target aging conditions and the electrical analysis was completed, LiFePO4 batteries were then dismantled and examined by electrochemical detections such as SEM, XRD and FT-IR in order to analyze correlations between electrical and electrochemical performances of LiFePO4 batteries under different aging conditions. Thermal analysis was also conducted to ensure surface temperatures of batteries didn’t exceed the suitable operating temperature for LiFePO4 batteries.