Transient thermal storage of excess heat using eutectic BiSn as phase change material for the thermal management of an electronic power module: design, technology, performance and reliability within a system approach

Novel concepts in power electronics rely heavily on the availability and processability of new materials and packaging technologies to meet the requirements of increasing performance and reliability at lower form factor, weight and cost. Today's main technological route for converter modules is still the power die soldered and wire-bonded to a DCB substrate. New applications or semiconductor technologies like e.g. SiC, however, require enhanced thermal management using standard commercial casings within the same, usually very limited thermal budget. This paper is the final of a series of publications dealing with a novel thermal management concept for power electronics enabled by the use of advanced packaging technologies as well as smart handling of power transients, making use of a TEC and a thermal buffer using a low melting BiSn eutectic as phase change material to store excess heat temporarily exploiting the PCM's enthalpy of fusion. This concept is exemplified on a typical six-pack converter module for industrial applications (4 kW, 1200 Volts) to be integrated into a standard easyPIM casing while being able to cope with overload power pulses. This paper summarises the whole system approach, references back to literature for details finishes the series of papers with the reliability analysis of the buffer technology. Thus, all stages of product development covering design, technology and performance are finally highlighted.