Hybrid Electric Vehicle Power Systems Receive Major Upgrade

Hybrid Electric Vehicle Power Systems Receive Major Upgrade

A leading company specializing in the design and production of materials for electronic thermal management, now uses AlSiC (Aluminum Silicon Carbide), a metal matrix composite ideally matched for base plates material for insulated gate bipolar transistor (IGBT), used in power control, high-power traction, fly-by-wire applications, and Hybrid Electric Vehicle power systems.

The low isotropic coefficient of thermal expansion (CTE) value of AlSiC-9 (8 ppm/°C: 30 – 100°C) is compatible with the thermal expansion value of the substrate or die used in IGBT power modules. The AlSiC CTE match lowers the mechanical stresses on IGBT die and substrates that are introduced by thermal power cycling, improving dependability of substrate attachment and reducing die cracking failures.

The device compatible AlSiC CTE removes the need for stress compensation material layers which are required in Copper (CTE = 17ppm/°C) baseplate assemblies. Removal of stress compensation materials simplifies baseplate assembly and decreases thermal resistance for AlSiC systems, meaning AlSiC systems have equal or improved thermal dissipation over Copper baseplate assemblies.

In high power applications (> 1200 V/ 400 A), IGBT modules assembled with AlSiC baseplates are found to have a service reliability of many times more thermal power cycles over Copper equivalent systems.

AlSiC is a lightweight material (1/3 that of Copper), which makes it an ideal cooler material for the weight-sensitive IGBT applications. AlSiC has higher strength and stiffness than Copper, which, combined with its lightweight nature, makes AlSiC assemblies more tolerant to shock and vibration.

The CPS AlSiC near net-shape fabrication process both produces the composite material and fabricates the product geometry, creating the design of IGBT base plates with a dome profile. This geometry improves thermal interface contact with cold plates and coolers. CPS fabricates standard of 190 mm x 140 mm, 140 mm x 130 mm and 140 mm x 70 mm base plate formats (shown) as well as custom formats.

Author: Darren Kincaid