Abstract
Electromechanical structural integrity and thermal stability dictate the safety performance of lithium-ion batteries. Progressive deformation and failure across microscopic and macroscopic lengths scales that are responsible for internal short circuit (ISC) in lithium-ion cells under mechanical abuse conditions remains elusive. In this study, a series of indentation tests were conducted on lithium-ion cells with different capacities up to the occurrence of ISC. The external response and internal configuration of these cells were investigated. It is discovered that cells with different capacities and state of charges exhibited different behaviors. Maximum temperature, which is often regarded as the most important parameter related to thermal runaway (TR), varied considerably due to the complicated contact configurations. X-ray computed tomography (XCT) showed that ISC was a collective result of shear band or other strain-localization modes in the electrode assembly, shear offsets in the granular coatings of electrodes, and the accompanying ductile fracture in the metal foils. We believe that the irregular strain-localization modes (kinks, cusps, and buckles), radical mismatches in mechanical properties of different layers, and geometric features of the indenter eventually lead to the tearing/puncture of cell separator at various locations. The results could provide useful guidance for the micromechanical modeling of lithium-ion cells.
Original language | English |
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Article number | 227939 |
Journal | Journal of Power Sources |
Volume | 455 |
DOIs | |
State | Published - Apr 15 2020 |
Funding
This work was sponsored by the Office of Electricity of the Department of Energy under Dr, Imre Gyuk and was carried out at Oak Ridge National Laboratory under contract DE-AC05-00OR22725 with UT-Battelle, LLC. X. Zhu wants to thank, in particular, the support from China Scholarship Council (No. 201806030115 ). X. Wang and Y. Gao acknowledge partial support from Center for Materials Processing at the University of Tennessee.
Keywords
- Failure mechanisms
- Internal short circuit
- Lithium-ion cells
- Mechanical deformation