Wevo’s WEVOPUR 60210 FL T polyurethane potting protects battery management PCBs

Wevo has developed WEVOPUR 60210 FL T, a polyurethane compound for the selective potting of multilayer printed circuit boards in automotive battery management systems. The system is applied by the dam-and-fill method and is built for boards that monitor and control voltages of up to 800 V in electric vehicles.

Diagnostic, communication and safety functions have pushed up the integration density of these boards, which have to withstand mechanical stress, changing environmental conditions and high operating temperatures. Potting encases a circuit board in a cured compound, a common way to shield automotive electronics from vibration, moisture and heat, and selective potting applies it only where it is needed so connectors and testing points stay accessible.

The compound has a Shore hardness of D 40 to 50 and a thermal conductivity of 0.8 W/m·K, and its dielectric strength exceeds 20 kV/mm. According to Wevo, the material absorbs shocks, vibrations and the stresses that come from fluctuating temperatures, and moving heat through the potted assembly helps reduce temperature differences between components and lowers the risk of stress cracks and solder joint detachment. The company adds that the cured compound fixes the components in place, is formulated to prevent electrochemical corrosion and protects them from moisture, and that optimized adhesion forms a durable bond with the substrate to help prevent delamination.

In the dam-and-fill process, the compound works as both barrier and filler. Wevo says the flow behavior and thixotropy are tuned so the barrier holds its shape while the filler wets the area to be protected without trapping air pockets. Layer thickness and the amount of material can be adjusted to different PCB geometries by changing the process design and application speed.

Wevo formulated the system to run on standard two-component mixing and dosing equipment, which the company says reduces the work involved in material qualification, storage and process management.

Source: Wevo