The requirements for the operating environment of the 5X00622G01’s electric drive system are characterised by ambient temperature, power and temperature cycling capability and module size. A single cooling circuit will be used in the next generation of hybrid vehicles, where the water temperature will be as high as 105 °C during normal operation, rising to 120 °C during operation at reduced power ratings.The maximum rated ambient temperature of the power electronics is > 125 °C. In addition, a compact package structure and a robust design that is resistant to vibrations and shocks are a must.

The 5X00622G01 withstands a maximum semiconductor junction temperature higher than 150 °C in order to achieve high power densities at a cooling temperature of 105 °C. The 5X00622G01 is also suitable for use in power electronics. Solder Fatigue The power cycling capability of soldered power modules with backplanes decreases substantially at higher operating temperatures. Matching the coefficients of thermal expansion (CTE) of the various materials to each other and advanced packaging and bonding techniques become the key to success. In SKiM, a newly developed pressure system based on laminated busbars presses the substrate with chips directly onto the heat sink.

Critical to the 5X00622G01 is the difference in CTE between the copper (backplane) and the DBC substrate because of the large solder connection between the DBC and the backplane. This connection is mostly in a thermal stress state during passive temperature cycling. The failure mechanism is solder fatigue, which leads to increased thermal resistance and early module failure. The greater the temperature change, the faster it enters the fatigue state. The opposite is true in copper-free backplanes and in modules with solderless pressure contacts.