Failure detection in commercial thermoelectric modules using infrared thermography

This work presents the possibility of using infrared (IR) thermography as a fast, contactless and therefore nondestructive inspection method to detect failures in commercial thermoelectric (TE) modules. For this the TE modules were thermally excited by internal Joule heating. The temperature at the hot side of the TE module was recorded with an IR camera having a thermal resolution of 20 mK and is sensitive in the spectral range of 3 – 5 μm. The IR thermography was carried out on failure free and faulty TE modules. To get information on the possible nature of the failures also a three-dimensional cone-beam Xray Computer Tomography was carried out. In the case of the failure free TE modules weak failures with probably faulty solderings were found which may lead to a malfunction during the normal life time. In the case of the faulty TE modules the main failure mode was also faulty soldering and in addition cracks were found in the legs. Numerical simulations were carried out on failure free and faulty TE modules to study the influence of failures on the temperature distribution on the upper cover plate.