Investigation on Electrochemical Properties and Degradation Mechanism of Cylindrical-Type Li-Ion Rechargeable Battery without Deconstruction

Abstract

Recently Li-ion rechargeable battery (LIB) has been widely used as power source of not only portable device but also electric vehicle (EV). For LIBs in EVs, a long life of 10 years or more is required. Therefore, a great deal of effort has been made to develop the prediction method of life of LIB for EV. We have already started to measure battery performance for LIBs being used in practical EVs and developed the prediction method of battery life based on the degradation mechanism of the active materials in the batteries. In this paper, we investigated battery performance of cylindrical-type cells with Sn-containing negative electrode. Sn-containing materials are promising negative electrode materials for LIB because of large theoretical capacity compared with that of conventional carbon materials. Both general cycle and storage tests were carried out for each 25 cells at 298 K and 318 K, and the capacity, DC resistivity and power density of these cells were checked every fixed period. We also applied the X-ray CT method to cells as an analytical technique without deconstruction, and confirmed visually to detect the internal structure in the cells definitely. In the presentation, we will discuss the degradation mechanism of the cells using Sn-containing negative electrode mainly by the combination of the prediction method of battery life and the X-ray CT method without deconstruction of cells. Acknowledgement This work was partly supported by the New Energy and Industrial Technology Development Organization (NEDO).