15 sealing function, EJOT has developed a FDS® screw equipped with a combined aluminum sealing washer. The sealing washer used by EJOT meets the stringent tightness requirements, even under the 24-hour climate change test required by the automotive industry. A notable feature of the FDS® technology is its suitability for applications with single-sided access to the joint. Since fastening can be done directly without pre-drilling the component, preparatory steps like pre-drilling or thread cutting are unnecessary. This eliminates tolerance issues associated with through holes and screw-in holes. The clearance-free fit between the screw-in part and the screw thread, achieved during flow drilling, results in high loosening torques and enhanced vibration resistance. Consequently, additional security elements are redundant. As the FDS® screw connection is detachable, the battery box can be easily opened and closed for maintenance, repair or recycling purposes. Repeat fastening is also feasible with metric screws, thanks to compatible thread geometry. Power electronics Power electronics are at the heart of an electric vehicle’s powertrain. The inverter, for instance, transforms the battery’s DC voltage into AC voltage to power the electric motor. It ensures precise control of the electric motor, contributing to a dynamic and efficient driving experience. Achieving exceptional power density and reliability are the primary development objectives for OEMs. For the demanding application field of power electronics, EJOT offers a broad product portfolio tailored to specific customer requirements. To attain a compact and efficient design that integrates multiple functions within single housing, inverters often feature stacked circuit boards. To ensure proper functionality, these PCBs must be electrically isolated from one another. This isolation is achieved using spacers inserted between the individual boards (Fig. 3). The VOLTtec® PCB Spacers comprise an ALtracs® Xt screw, designed with a plastic overmold on the head. This metal-plastic combination ensures a precisely defined distance between the PCBs. During assembly, the first PCB is fastened into the die-cast aluminum using the ALtracs® Xt self-tapping thread. Subsequently, the next circuit board is directly fastened into the plastic overmold on the head using an EVO PT® screw. The high technical demands of this application are further underscored by the customer’s requirement for a dielectric strength of 4 kV, both between PCBs and the screw connections. This dielectric strength is rigorously tested on standardized production cells within the EJOSYST® area. The PCB Spacers developed by EJOT not only ensure safe electrical decoupling of the circuit boards but also contribute to a compact and efficient design. Copper components are used in the power electronics of electric vehicles to reliably conduct high currents and effectively dissipate the generated heat. For high-voltage applications (Fig. 4), EJOT manufactures high-precision cold-formed copper parts through a multi-stage cold forming process, marketed under the EJOFORM® brand. This technology transforms a wire section into a customized cold-formed part over several forming stages. Compared to the commonly used turned parts, cold forming offers cost-effective and resource-efficient large-scale production, high material utilization and enhanced component properties. The precisely manufactured EJOFORM® copper components can be further refined by various processes. Meeting the highest standards for technical cleanliness, burr-free finishes, dimensional accuracy, shape or position tolerances and surface precision, these complex parts can also be machine finished at EJOT. The aim is to provide customers with a flawless result from a single source through the optimal integration of all process steps. EJOT upholds this high standard across all electromobility projects. Beyond technical expertise, close and collaborative cooperation with customers is pivotal to success. www.ejot.com/industry VOLTtec® PCB Spacer for stacked boards ● Ensures dielectric strength ● Features self-tapping thread for light metals ● Incorporates plastic-molded head as screw-in point EJOFORM® copper contacts with high electrical conductivity ● Economical due to material-saving technology ● Fully aligned with application requirements ● Meets highest tolerance requirements Fig. 3 Fig. 4 Images: ©EJOT
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