Does the fact that the heatsink of the power device on the BMS control board is not grounded make it a radiating antenna?

If the heatsink of a power device is not properly grounded, it can potentially become a highly efficient radiating antenna. With its large surface area, a floating heatsink allows high-frequency voltages from the power device's switching to couple to it via parasitic capacitance, driving common-mode radiation. The solution is to connect the heatsink to the system's power ground via a low-impedance path. This can be achieved using a thermally conductive insulating pad, a grounding spring, conductive paste, or multiple screws to ensure good grounding and low contact resistance. This fixes the heatsink's potential to ground, effectively short-circuiting the potential antenna and suppressing its radiation efficiency, preventing it from becoming an additional noise source.