KEYNOTE PCIM 2021: Next generation of power electronics module packaging
To improve efficiency in modern cars and achieve true electromobility, power density must increase without inhibiting performance and reliability. In a keynote on May 5th, Hannes Stahr of AT&S discusses how high-efficiency power packaging could help achieve this.
A power electronics module is a circuit carrier, such as a substrate or a printed circuit board, that has more than one topological switch, such as an insulated-gate bipolar transistor (IGBT) or a metal-oxide-semiconductor field-effect transistor (MOSFET). A power electronics module must also include at least one—but usually includes several—current paths with diodes as well as additional passive components, such as a capacitor or temperature sensor.
During a PCIM Digital Days 2021 keynote on May 5, Hannes Stahr, Technology Manager at AT&S, took attendees through what he calls the next generation of power electronics module packaging.
Why packaging matters
The global automotive market has been in a crisis for several years, and the COVID-19 pandemic is worsening this situation. Up until 2017, the number of manufactured cars increased up to 96 million, 2018 then followed with a stable number, but in 2019 the numbers declined by around 4.5 %. In 2020 the number of produced cars could drop to 75 million and further in 2021.
Despite this, China has reported an increase in sales numbers of 8.5 % over the last three months and has become the rescuer of the German automotive industry. In 2018, Volkswagen, Daimier, and BMW owed 35.6 % of their worldwide turnover to China.
In addition, the EU is aiming for a reduction in CO2 emissions down to 95 g CO2/km on average by the end of 2021 and a further reduction to 60 g CO2/km by 2030. At the same time, the EU wants significant reductions in fuel consumption.
According to Stahr, these goals are only reachable with high-voltage electrification, based on HV power semiconductors and power packaging with high efficiency. To improve efficiency in modern cars, power density must increase without limitations on performance and reliability. While many things need to be considered to realize such improvements, new module concepts are an important one, and concepts with wide bandgap (WBG) semiconductors are the best candidates.
Watch the whole keynote here:
Prioritizing thermal management
Stahr says that research priority for developing next-gen module packaging is on thermal management and the handling of high current. This requires the reduction of inductance, switching losses, and on-state losses of the power switches to drive up the efficiency of power modules to the 95 % and higher range.
The implementation of power semiconductors like MOSFETs and IGBTs mentioned earlier directly into the PCB is a promising approach that could fulfill these requirements. According to Stahr, AT&S recently utilized its expertise in embedded components packaging (ECP) technology for the implementation of efficient power packages and modules.
This, he claims, made it possible to drastically reduce the space required for power packages by up to 50 % while increasing power density. Additionally, it showed positive results are achievable in terms of switching behavior, thermal management, and power cycling.
Potential applications for embedding as highlighted by Stahr include wind energy, electric vehicles, on-board chargers, industry, smart home products, and data centers. This of course depends on the WBG material used—e.g., SiC or GaN—due to the differences in key metrics like power, switching frequency, and target voltage.