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How to solve the problem of heat dissipation between power modules?

The power module heating problem will seriously damage the reliability of the module, so that the failure rate of the product will increase exponentially. What should I do if the power module heats up seriously? High temperature has a greater impact on the reliability of power modules with high power density. High temperature will lead to a reduction in the life of electrolytic capacitors, reduced insulation characteristics of transformer enameled wires, damage to transistors, thermal aging of materials, cracking of low-melting-point welds, peeling of solder joints, and devices. Increased mechanical stress and other phenomena.

In many applications, the heat on the power module substrate is conducted to the farther heat dissipation surface through the heat conducting element. In this way, the temperature of the power module substrate will be equal to the sum of the temperature of the heat dissipation surface, the temperature rise of the heat conduction element and the temperature rise of the two contact surfaces. The thermal resistance of the heat-conducting element is proportional to its length and inversely proportional to its cross-sectional area and thermal conductivity. Choosing appropriate thermally conductive materials and cross-sectional area can also reduce the thermal resistance of the heat-conducting element. 

Thermally pad are an important factor that affects performance, and care should be taken when selecting them. In most applications, the heat generated by the power module will be conducted from the substrate to the heat sink or thermally conductive element. However, there will be a temperature difference on the contact surface between the power module substrate and the heat conduction element. This temperature difference must be controlled. The thermal resistance is connected in series in the heat dissipation circuit. The temperature of the substrate should be the temperature rise of the contact surface and the temperature of the heat conduction element. Sum. If not controlled, the temperature rise of the contact surface will be particularly noticeable. The area of the contact surface should be as large as possible. In order to eliminate the unevenness of the surface, the contact surface should be filled with thermally conductive silicone gaskets, and after taking appropriate measures, the thermal resistance of the contact surface can be reduced.

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