What Is Electromagnetic Pulse Technology?
Electromagnetic pulse technology (EMPT) is a technique used in the automotive industry to join conductive materials for high-voltage applications.
As the automotive industry shifts to electric vehicles, new manufacturing methods are needed to deliver the high-voltage wire harnesses required for electric propulsion. EMPT overcomes some of the limitations of traditional welding and mechanical joining methods, making it an important tool to meet the performance demands of modern EV manufacturing.
How does EMPT work?
EMPT relies on the principles of electromagnetic forming, a process used to shape conductive materials. Special machinery rapidly discharges a large amount of energy through a coil surrounding the metal components. One material is typically positioned inside of or adjacent to the other. The current passing through the coil generates a strong magnetic field that causes the conductive materials to move rapidly, pressing them together and creating a metallurgical bond at the interface.
Creating a metallurgical bond is like combining protein powder with water in a shaker bottle. When the container is shaken, the powder and water combine, forming a solution. However, in a metallurgical bond, the connection happens at the atomic level. The atoms from each metal directly interact with the atoms of the other, sharing electrons in the process and forming a continuous, permanent bond.
A metallurgical bond occurs at the atomic level.
Advantages of EMPT
For automotive applications, the metallurgical bond formed by EMPT has several advantages over traditional joining methods. Crimping, the standard methodology for joining cables to connectors, involves mechanically compressing pieces together to create a conductive connection. High-voltage applications require thicker wires, which are harder to mechanically compress because more force is required to squeeze them together. Some of the other advantages of EMPT include the following:
Robustness: Compared with crimping, EMPT produces stronger joints, with up to 300% more terminal pullout resistance. Terminal pullout resistance and vibration resistance are especially important in EVs, where they prevent high-voltage cables from disconnecting in the event of a crash.
Less resistance and heat: The strength of the terminal connection also correlates to less overall resistance, which reduces heat generation.
Retention of material properties: Unlike traditional welding, EMPT is a cold-forming method, meaning the materials do not undergo significant heating during the joining process. This helps maintain the materials’ properties and precise dimensions.
Flexibility for joining different metals: EMPT is particularly effective for joining different metals that would be difficult to weld using conventional methods, such as aluminum and copper, which have vastly different melting points and thermal expansion properties.
Contact-free assembly: EMPT does not require physical tools to touch the workpieces during the joining process, reducing wear on tooling and minimizing contamination and surface damage.
A system-level approach enables optimized trade-offs
EMPT is becoming more important for applications that require high-precision, low-heat input and where dissimilar metals must bond, such as in the production of electrical connectors and busbars for high-power applications. EMPT is particularly advantageous in commercial vehicles, which require higher-gauge cables than smaller vehicles, making crimping less practical.
A system-level approach is essential to delivering solutions that balance trade-offs between different manufacturing methodologies and materials. Aptiv’s experience as a system integrator and full portfolio of high-voltage components enable us to maximize performance while reducing weight and costs.