Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 08, 2024 - September 11, 2024
Due to the poor plasticity of oxide-based electrolyte such as LLZO, and LTPO used in oxide based all solid-state lithium ion batteries, volume change in active materials during charge/discharge processes in other words lithium insertion and extraction from the active materials causes residual stress. Considering the volume change rates of the various active materials, which can reach several percent, and the fracture strength of oxide ceramics, which is typically in the hundreds of megapascal range, such residual stress is not negligible from perspective of mechanics of materials. Consequently, the prediction of residual stress is crucial for the optimization of oxide-based ASSLiB design. However, the methodology is still evolving due to the lack of established design principles and the variability of materials employed in ASSLiB. In this study, we focus on the macroscopic volume change of the oxide based ASSLiB cells and relate it to the cell design and component materials, employing a materials science approach. The commercialized low-capacity cell (100 μAh, 1.5V, CeraCharge TM, TDK) consists of the LVPO active material, the LTPO electrolytes, and the copper current collector. The configuration is symmetrical, with each layer stacked to form a rectangular cell (4.4 × 3.0 × 1.1 mm3). A strain gauge was attached to the horizontal direction to the layer and horizontal strain was measured. The results demonstrated notable repeatability in the charge/discharge processes, with a recorder value of 150 με at charge amount of 0.2 C.
