In-Plane Compressive Lithium-Ion Battery Cells

Compressive Behavior of Representative Volume Element Specimens of Lithium-Ion Battery Cells under Different Constrained Conditions

Shin-Jang Sung, William Lai, Jwo Pan, Yusuf Ali (Ford) and Saeed Barbat (Ford)

The compressive behavior of lithium-ion phosphate battery cells is investigated by conducting in-plane constrained compression tests of representative volume element (RVE) specimens.  The results for cell RVE specimens under in-plane constrained compression tests without pre-strains and with pre-strains in the out-of-plane direction indicate that the load carrying capacity is characterized by the buckling of cell specimens.  As the pre-strain increases, the nominal compressive stress-strain curve becomes higher.  Based on the elastic buckling analyses for a beam with different lateral constraints due to different pre-strains in the out-of-plane direction, the number of half waves and the buckling stresses were obtained. The results indicate that the number of half waves and the buckling stress increase as the pre-strain increases.  The general trends of the numbers of half waves and the buckling stresses agree with those obtained from experiments.

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Figure 1. A schematic of (a) a pouch cell and a cell RVE specimen for the in-plane constrained compression test, (b) a cell RVE specimen with the dimensions, and (c) a side view of a small portion of the cell RVE specimen showing the individual cell components.  The large red arrows indicate the compressive direction.

 
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Figure 2. Deformation pattern of a cell RVE specimen after the in-plane constrained compression test the out-of-plane compressive pre-strains of (a) 0% and (b) 3.2% at the in-plane compressive strain of 38% and 36 %, respectively.

Figure 3. The in-plane nominal compressive stress-strain curves of four cell RVE specimens with the out-of-plane compressive pre-strains of 0%, 3.2% and 11%, tested at a displacement rate of 0.5 mm/min (nominal strain rate of 0.0003 s-1).

  1. S.-J. Sung, W.-J. Lai, M. Y. Ali, J. Pan and S. Barbat, 2014, “Compressive Behavior of Representative Volume Element Specimens of Lithium-Ion Battery Cells under Different Constrained Conditions,” SAE International Journal of Materials and Manufacturing 7(2), pp. 480-487. DOI: 10.4271/2014-01-1987.  (SAE 2014-01-1987)