  Spatial distributions in current, temperature, state-of-charge and
degradation across the plane of large format lithium-ion battery pouch cells
can significantly impact their performance, especially at high C-rates. In this
paper, a method to smooth out these spatial distributions by grading the
electrode microstructure in-the-plane is proposed. A mathematical model of a
large format pouch cell is developed and validated against both temperature and
voltage experimental data. An analytic solution for the optimal graded
electrode that achieves a uniform current distribution across the pouch cell is
then derived. The model predicts that the graded electrodes could significantly
reduce the likelihood of lithium plating in large format pouch cells, with
grading increasing the C-rate at which plating occurs from 2.75C to 5.5C. These
results indicate the potential of designing spatially varying electrode
architectures to homogenise the response of large format pouch cells and
improve their high rate performance.
