Damage prediction of very high cycle fatigue of high-capacity battery electrodes based on multi-scale modeling

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K04078
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 18010:Mechanics of materials and materials-related
• Research Institution: Tokyo City University
• Principal Investigator: Kobayashi Yukiyoshi 東京都市大学, 理工学部, 准教授 (90295014)
• Co-Investigator(Kenkyū-buntansha): 岸本 喜直 東京都市大学, 理工学部, 准教授 (20581789)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 機械材料・材料力学 / 疲労 / 二次電池 / マルチスケール / マルチフィジックス

Outline of Final Research Achievements

This study attempted to develop a method for predicting ultra-high cycle fatigue damage based on multi-scale modeling for electrode materials, which are particularly vulnerable components of high-capacity secondary batteries such as lithium-ion batteries. Specifically, a plane-bending fatigue test was conducted to construct a mathematical model that relates the microscopic fatigue damage process on the order of micrometers to the deformation of the electrode material on the order of millimeters when the electrode material is repeatedly subjected to low stresses for more than one million cycles before damage occurs. Comparison with various fatigue tests shows that low to high cycle fatigue is caused by energy dissipation and that very high cycle fatigue can be defined as fatigue when the stress amplitude is below the lower limit.

Free Research Field

機械材料・材料力学

Academic Significance and Societal Importance of the Research Achievements

リチウムイオン二次電池をはじめとする高容量の二次電池を長期間に渡って運用する場合，機械振動による外荷重や充放電時の発熱によって生じる熱応力が繰返し生じることによって，電極材を支えるバインダーが機械的に疲労し，やがて破断に至る．本研究で提案した力学モデルを用いて種々のバインダー濃度の電極材に巨視的な損傷が生じるまでの繰返し数を予測したところ，良好な予測精度を示した．これは電極材を構成する活物質とバインダーの配合比を変更した場合であっても同様であったことから，本研究の成果は振動や熱変形に長時間晒される機械構造物の動力源として運用する際，構造物全体と電極の相互作用に基づいた安全寿命設計に貢献できる．