Countermeasures Against Electrical Erosion in 800V EV Drivetrains

The electrification trend of recent years, especially HEV and BEV, has brought new challenges for durable powertrain solutions. Various types of electrical currents occur in the e-motor and, therefore, come into contact with powertrain components and bearings. These currents can lead to electrical erosion and, consequently, damage the bearings. A well-established countermeasure is the use of hybrid bearings with rolling elements made of ceramic. While hybrid bearings work well technically, they are comparatively cost-intensive. The increasing use of faster-switching SiC semiconductors in combination with an 800V system architecture will significantly increase the occurrence of these parasitic currents in electric vehicles. This visible trend urges the industry to develop new cost-efficient and reliable solutions against these phenomena. With the insulated bearing through injection over-molding, NSK aims to provide a cost-efficient solution. The presentation will give an overview of the design, test results, and current development status.