Module Level Thermal Propagation Verification under EU Regulation Guidelines
EU battery regulation requires module thermal propagation testing with five-minute occupant warning signals before external flammability occurs.
Ceramic Heater Trigger
Meaning
Heating element assembly designed to deliver a rapid thermal impulse represents a standard method for initiating cell-level failure. In safety evaluation tests, the ceramic heater trigger provides localized energy to force a target cell into thermal runaway. This allows engineers to observe whether the failure propagates to adjacent cells.
The boundary of its application lies in the physical space of the pack, as it requires direct contact with the cell surface.
Energy Delivery
Power supplies of high wattage feed current to the resistive element to generate the required thermal spike. This process forces the ceramic heater trigger to reach temperatures exceeding six hundred degrees Celsius within a few seconds. Rapid heat transfer mimics the internal short circuit conditions of a true field failure.
Thermal Performance
Localized thermal energy must penetrate the cell casing without preheating the neighboring cells. If the ceramic heater trigger raises the temperature of adjacent cells before the target cell fails, the test results become invalid. Guarding against this scenario requires insulating material behind the heating element.
Test Limitation
Mechanical constraints of dense pack designs often prevent the installation of these devices. Squeezing a ceramic heater trigger between cells can modify the pressure profile of the module. This altered pressure change affects how the gas vents during the test.