Multi Axial Creep Fatigue Damage Accumulation in Vacuum Brazed Battery Pack Cooling Structures
Vacuum brazed aluminum cooling plates fail under coupled multi-axial creep-fatigue when pressure pulses interact with static cell swelling constraints.
Structural Integrity
Meaning
Ability of a battery pack enclosure to withstand external forces and internal pressures prevents internal damage or leakage of hazardous materials. Maintaining structural integrity protects the cells from deformation during vehicle collisions or dropped package events. This quality ensures the long-term safety of the battery pack.
Mechanical Load
Dynamic forces during operation subject the battery housing to continuous vibrations and potential shock impacts. If the structural integrity of the frame fails, high voltage lines can touch the metal casing. This failure creates short circuits that can lead to fires.
Safety Consequence
Enclosure deformation during a crash must be minimised to prevent the intrusion of sharp objects into the cell space. Ensuring structural integrity avoids the puncturing of cell walls, which causes immediate thermal runaway. It acts as the final line of defence in the event of severe vehicle impacts.
Testing Method
Heavy mechanical presses and vibration tables simulate worst-case stress events to verify the resilience of the casing. Engineering validation of structural integrity involves applying multi-axis vibration profiles that simulate years of road travel in a few days. The pack must show no signs of metal cracking or seal separation after these tests.
It must also retain its seal against moisture and dust ingress to pass certification.