Meaning
Computational tool that simultaneously calculates the temperature distribution and the resulting physical stresses or deformations in a material. This software couples heat transfer equations with structural mechanics to model how parts expand, contract, or weaken when subjected to thermal loads. A thermomechanical solver is indispensable for evaluating the durability of battery components that experience temperature swings, such as busbars and cooling manifolds.
It identifies potential failure points where thermal expansion might lead to plastic deformation or fatigue cracking.
Coupled Analysis
Temperature field acts as a direct input to the mechanical equations by inducing thermal strains. The thermomechanical solver accounts for the fact that material properties like Young’s modulus and yield strength change as the battery heats up. This ensures that the predicted stresses are accurate even under the extreme temperatures of a fast charge event.
Structural Integrity
Expansion of individual cells within a rigid module can generate significant pressure on the end plates and housing. Using a thermomechanical solver allows engineers to design the pack enclosure with enough compliance to handle these loads without rupturing. The simulation tracks the evolution of stress throughout the entire life cycle of the system.
Fatigue Prediction
Repeated cycles of heating and cooling cause microscopic damage that can eventually lead to the failure of electrical connections. A thermomechanical solver calculates the accumulated strain at weld points and bolted joints to estimate the time until a crack initiates. This data helps in selecting materials that can survive the ten or fifteen year service life required for energy storage applications.
