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Title: Progressive mechanical indentation of large-format Li-ion cells

We used large format Li-ion cells to study the mechanical responses of single cells of thickness 6.5 mm and stacks of three cells under compressive loading. We carried out various sequences of increasing depth indentations using a 1.0 inch (25.4 mm) diameter steel ball with steel plate as a rigid support surface. The indentation depths were between 0.025 and 0.250 with main indentation increments tests of 0.025 steps. Increment steps of 0.100 and 0.005 were used to pinpoint the onset of internal-short that occurred between 0.245 and 0.250 . The indented cells were disassembled and inspected for internal damage. Load vs. time curves were compared with the developed computer models. Separator thinning leading to the short circuit was simulated using both isotropic and anisotropic mechanical properties. This study show that separators behave differently when tested as a single layer vs. a stack in a typical pouch cell. The collective responses of the multiple layers must be taken into account in failure analysis. A model that resolves the details of the individual internal cell components was able to simulate the internal deformation of the large format cells and the onset of failure assumed to coincide with the onset of internal shortmore » circuit.« less
Authors:
ORCiD logo [1] ;  [1] ;  [1] ; ORCiD logo [1] ;  [1] ; ORCiD logo [1] ;  [2] ;  [2] ;  [2] ;  [3]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Naval Surface Warfare Center (NSWC), Carderock, MD (United States)
  3. National Highway Safety and Transportation Administration, Washington, DC (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Journal of Power Sources
Additional Journal Information:
Journal Volume: 341; Journal Issue: C; Journal ID: ISSN 0378-7753
Publisher:
Elsevier
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V)
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; Li-ion cells; Indentation; Mechanical deformation; Simulation
OSTI Identifier:
1360081