Long Term Interconnect Creep and Weld Fatigue under Cyclic Thermal Load in Heavy Formats
Thermal expansion and cell swell induce cyclic shear stresses that trigger weld fatigue and interconnect creep, requiring compliance flexure loops.
Strain Range Partitioning
Meaning
Fatigue analysis methods break down the total strain experienced by a material into elastic and plastic or creep components to predict failure under complex loading. In the design of battery thermal plates, strain range partitioning helps engineers understand how the metal will react to the combined stress of internal pressure and thermal cycling. This approach is more accurate than simple fatigue models.
Deformation Mode
Different combinations of stress and time result in varying rates of damage accumulation within the grain structure. Using strain range partitioning allows for the identification of the most damaging phase of the operating cycle.
Life Estimation
Summing the damage from each partition provides a total life expectancy for the component. The accuracy of strain range partitioning depends on high quality laboratory data for the specific alloy used in the cooling system.
Engineering Application
Designers apply these calculations to optimize the thickness and the geometry of the fluid channels within the heat exchanger. When strain range partitioning reveals a high risk of plastic deformation, the material specification may be upgraded to a higher strength grade. This detailed analysis prevents the premature leakage of coolant into the battery module, which could cause a major electrical failure.
The method is particularly useful for parts that operate near their melting point or under frequent start stop conditions. Constant refinement of the model ensures that the safety margins remain lean but effective.