The present invention concerns a method and a device for estimating a level of damage or a lifetime expectation of a power semiconductor module comprising at least one die that is mechanically, thermally, and electrically attached to a substrate, composed of plural layers of different materials. The invention: obtains power losses of the power semiconductor module, obtains the temperature in at least two different locations of the power semiconductor module, estimates a thermal model between the at least two different locations of the power semiconductor module using the determined power losses and the obtained temperatures, determines if a notification indicating the level of damage or the lifetime expectation has to be performed according to the estimated thermal model and a reference thermal model. notifies the level and location of damage or the lifetime expectation if the determining step determines that the notification has to be performed.