Study on mechanical properties of Lithium-ion battery in hydrothermal salt spray environment under different mechanical abuse conditions

Lithium-ion batteries are valued for energy efficiency and long lifespan, yet their performance under extreme environmental conditions is not well understood. This study investigates the effects of hydrothermal salt spray and mechanical stresses, through a combination of accelerated environmental testing and mechanical property analysis. The findings reveald significant casing deterioration due to corrosion, with the elastic modulus decreasing by 76.4 %, 20.5 %, and 18.4 % at 0°, 45°, and 90° orientations, respectively. Gaps in the tab structure allowed NaCl infiltration, causing swelling and compacting of jellyroll structures and mitigating mechanical property degradation. The peak force after corrosion decreased by 12.2 % and 11.6 % during axial and three-point bending compression, respectively, but increased by 4.9 % during radial compression. In dynamic tests, the peak force after corrosion decreased by 13.9 % under hemisphere hammer impact but increased by 15 % under flat hammer impact. Voltage tests indicate that the time required for corrosion to lead to complete failure of the battery four times longer in a fully charged state compared to a depleted state. This emphasized maintaining a higher charge level to improve battery reliability in extreme conditions. These findings provided practical insights for designing more durable batteries and optimizing performance in maritime environments, offering a foundational understanding of lithium-ion battery behavior under such challenges.