Does the power module get damaged after a surge test (line-to-line ±1kV) on the BMS control board?

Power module failure after line-to-line surge testing is typically due to ineffective overvoltage protection circuitry. Key causes include inadequate protection, insufficient component rating or slow response, and improper layout leading to parasitic inductance and additional voltage spikes. The solution is to add a fast-response TVS diode before the module input, with a clamping voltage lower than the module's maximum input voltage, and in coordination with the preceding MOV. It is crucial to ensure the protection device is properly grounded and that the trace distance from its output to the module input is minimized to reduce residual voltage. Proper component selection and optimized layout can effectively protect the downstream power module.