Design And Thermomechanical Analysis Of A Cell-Integrated, Tapered Channel Heat Sink Concept For Prismatic Battery Cells

Temporal and spatial temperature variations can negatively affect the performance, lifetime, and safety of Lithium-ion batteries used in electric vehicles. Air-cooled thermal management systems offer advantages in durability and simplicity. Here, we demonstrate a novel air-cooled system in which cooling features are integrated directly into the prismatic battery cells. When cells are stacked in a battery module, the topographic features integrated into the battery case contact each other and provide mechanical resistance against deformation due to internal battery pressure as well as form a plurality of cooling channels. A series of finite element analyses and conjugate heat transfer analyses are performed to identify the optimal geometric parameters for the design concept under consideration of both battery cell internal pressure and thermal loading. For a wide spacing between fins, the cooling efficiency is high when battery internal pressure is absent but low in the presence of cell deformation due to battery internal pressure. As the number of additional fins is increased, the effect of deformation on cooling performance decreases. Consequently, there exists an optimal number of cooling fins. The utilization of tapered channels and the addition of secondary fins provides additional and significant improvements in temperature uniformity, however at cost of increased pressure drop and maximum temperature compared with the design of parallel channels. This study seeks to make two contributions. One contribution is a fundamental one in heat transfer. It addresses the performance of heat sinks under consideration of mechanical deformation of the heat sink. The other contribution is related to battery thermal management. It describes a novel approach to establish an effective cooling system for battery cells in battery packs with forced air cooling.