Design Parameter Trade-off for Packaging of Stacked Prismatic Batteries 2011-01-0667

Rechargeable energy storage systems with Lithium-ion pouch cells are subject to various ambient temperature conditions and go through thousands of charge-discharge cycles during the life time of operation. The cells may change their thickness with internal heat generation, cycling and any other mechanisms. The stacked prismatic cells thus experience face pressure and this could impact the pack electrical performance. The pack consists of stiff end plates keeping the pack in tact using bolts, cooling fins to maintain cell temperature and foam padding in between cells. The pack level thermal requirements limit the amount of temperature increase during normal operating conditions. Similarly, the structural requirements state that the stresses and the deflection in the end plates should be minimal. Uncertainties in cell, foam mechanical and thermal properties might add variation to the pack performance. A finite element-based model of the battery pack is built to study various design scenarios and boundary conditions. Further response surfaces are built to the numerical model to enable sensitivity analysis and efficient robust design to meet pack thermal and structural requirements.