MPDB® power box

SPE Award 2024 - 2nd place in the “enabler technology” category

MPDB® performance box

Raw material manufacturer: Celanese Sales Germany GmbH / AKRO-PLASTIC GmbH
Tool manufacturer: Erwin Quarder Systemtechnik GmbH
Parts manufacturer: Erwin Quarder Systemtechnik GmbH
Other parties involved: Infineon Technologies AG

The developed product technology sets new standards in performance and cost efficiency in the cooling of both single-sided and double-sided power modules for inverters, the heart of the electric drive. Optimized cooling enables lower chip temperatures at higher power, which reduces the resulting losses and thus increases the range per battery charge.

The system consists of two cooling units - bottom and top coolers - as well as a frame with the modules and a spring that completes the overall system by means of self-tapping screws. The performance and cost advantages of the product technology result from the following innovative processes:

• MPDB® process: The helium-tight, long-term stable composite of plastic and metal enables the substitution of milled aluminum components or die-cast elements. This leads to cost-effective production in multiple cavities using injection molding. FORTRON 1140L4 is ideally suited due to its CLTE values matching those of aluminum.

• Bottom cooler: The parallel water flow reduces the pressure loss and ensures that the individual power modules are supplied with fresh water at the same temperature. This reduces the overall thermal resistance (Rth) and increases performance.

• Top cooler: Three flexible high-performance cooling elements compensate for module tolerances and reduce the layer thickness of the thermal interface material, which also helps to increase performance and reduce losses.

• Spring: With 800 N per module, deformation of the module is prevented during operation. This avoids the so-called pump-out effect of the TIM and ensures long-term stability.

High-performance cooling elements in the bottom and top cooler:

1. High-gloss surfaces with a roughness of < 20 nm minimize the required TIM layer and reduce thermal resistance. This corresponds to thermal bonding processes such as sintering or soldering, but at significantly lower costs.

2. Micro-ribs with a distance of 0.3 mm maximize the exchange surface to the water, which maximizes energy dissipation with low pressure loss and thus minimizes losses when converting direct current (DC) to alternating current (AC).

• Frame: Consists of AKROTEK® PK VM 30 black (4896) due to its CTI value of 600. 1140L4 is ideally suited due to its CLTE values matching the aluminum.