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Title: Fragmentation of copper current collectors in Li-ion batteries during spherical indentation

Large, areal, brittle fracture of copper current collector foils was observed by 3D x-ray computed tomography (XCT) of a spherically indented Li-ion cell. This fracture was hidden and non-catastrophic to a degree because the graphite layers deformed plastically, and held the materials together so that the cracks in the foils could not be seen under optical and electron microscopy. 3D XCT on the indented cell showed “mud cracks” within the copper layer. The cracking of copper foils could not be immediately confirmed when the cell was opened for post-mortem examination. However, an X-ray radiograph on a single foil of the Cu anode showed clearly that the copper foil had broken into multiple pieces similar to the brittle cracking of a ceramic under indentation. This new failure mode of anodes on Li-ion cell has very important implications on the behavior of Li-ion cells under mechanical abuse conditions. Furthermore, the fragmentation of current collectors in the anode must be taken into consideration for the electrochemical responses which may lead to capacity loss and affect thermal runaway behavior of the cells.
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  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Power Sources
Additional Journal Information:
Journal Volume: 364; Journal Issue: C; Journal ID: ISSN 0378-7753
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
25 ENERGY STORAGE; X-ray tomography; Li-ion battery; Spherical indentation; Internal short circuit; Fragmentation
OSTI Identifier: