Thermal Shock Testing

Test Chamber

Equipment for this test consists of a chamber with separate hot and cold zones and an automated transfer basket that moves the sample between them. The basket moves the specimen in seconds, causing a rapid temperature change that is much faster than the gradual transition of a standard temperature chamber. Typical test profiles require the sample to stay in each zone for a specified dwell time to ensure the entire component reaches the target temperature.

The number of cycles can range from ten to several hundred. Engineers monitor the samples using diagnostic sensors to detect any electrical opens or short circuits during the transition.

Material Failure

Rapid expansion and contraction under these temperature shifts generate high mechanical stress at the boundaries between different materials. This stress can cause protective plastics to crack, wire bonds to break, and seals to fail. In multi-layer battery cells, thermal shock can cause the active layers to separate from the current collector foils, reducing the battery’s capacity and electrical performance.

These mechanical failures show which areas of the component need design improvements.

Sourcing Metric

Procurement specifications for battery management systems and battery packs require the components to pass a minimum number of thermal shock cycles without failure. Sourcing managers use these test results to qualify new suppliers and ensure their products are built to withstand real-world driving conditions. When a supplier submits a new design, they must provide a certified test report showing that the product passed the test.

This requirement ensures that only mechanically robust components are purchased.