Incremental Pressure Curves to Assess Capacity Fade in Next-Generation Li-Ion Pouch Cells

A methodology is presented for assessing the capacity fade in next-generation Li-ion pouch cells, subject to substantial lithiation induced volume changes, based on so-called incremental pressure curves. The methodology is evaluated on next-generation pouch cells with a Ni-rich NMC622 cathode against a Silicon-alloy/graphite anode. The cell is placed under volumetric constraints, which results in a measurable pressure variation during cycling. By analyzing the Incremental Pressure (dP/dV) curves over battery lifetime we show that the intensity of the curves' peaks is closely related to its capacity and thus can be used to assess capacity fade of next-generation Li-ion pouch cells.