Energy Storage Science and Technology ›› 2025, Vol. 14 ›› Issue (8): 3090-3099.doi: 10.19799/j.cnki.2095-4239.2025.0020

• Energy Storage Materials and Devices • Previous Articles    

Ball-head indentation-induced safety evaluation of capacitive lithium-ion batteries

Bin YANG1,2(), Jun YANG1(), Lang XU2, Haowei WEN1, Dengfeng LIU1, Dianbo RUAN1   

  1. 1.Faculty of Mechanical Engineer & Mechanics, Ningbo University, Ningbo 315211, Zhejiang, China
    2.Hesheng Alternative Energy Technology Co. , Ltd. , Ningbo 315040, Zhejiang, China
  • Received:2025-01-04 Revised:2025-02-21 Online:2025-08-28 Published:2025-08-18
  • Contact: Jun YANG E-mail:yangbin@nbu.edu.cn;13798961096@163.com

Abstract:

Local mechanical compression is one of the major contributors to thermal runaway in lithium-ion batteries (LiBs) during vehicle collisions. To investigate the failure mechanism of capacitive LiBs under localized indentation, ball-head indentation experiments were performed on 18650 capacitive LiBs. These batteries featured a positive electrode composed of Ni-Co-Mn oxide and activated carbon composite, and a negative electrode made of an extremely soft carbon/graphite composite. The failure process and temperature evolution behavior were analyzed. The effects of state of charge (SOC), indentation location, and secondary use on battery safety were systematically examined. The results show that the peak load decreases with increasing SOC, and the internal short-circuit deformation also diminishes as SOC increases. Damage near the positive terminal is more likely to induce thermal runaway, and elevated temperatures are observed as the damaged area expands. Once the indentation depth reaches a critical threshold, interlayer bending and radial cracking occur, axial electrode plates are damaged, the battery's lithium intercalation and deintercalation capability is considerably reduced, and severe self-discharge is observed. This study offers valuable insights into identifying short-circuit locations and vulnerable regions within the battery, providing a theoretical basis for improving the safety design of battery packs.

Key words: tabless, capacitive lithium-ion batteries, ball head indentation, thermal runaway

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