Do you know that power battery group technology has been applied by Tesla for more than ten years?

    Tesla has applied a specific application in ultrasonic welding technology to its battery system. Wire Bonding has made the application of ultrasonic welding technology in the field of power battery group connection more and more discussed. The application of ultrasonic welding on power batteries can be seen in the application of the main focus on the ear soldering, fuse welding.

Features of Ultrasonic Welding

• A wide range of weldable materials can be used for the welding of the same metal materials, especially high conductivity, high thermal conductivity materials (such as gold, silver, copper, aluminum, etc.) and some refractory metals, as well as dissimilar metals with widely varying properties. Materials (such as heat conduction, hardness, melting point, etc.), metal and non-metal, plastic and other materials, can also complete the thickness difference between the disparity material welding and the multi-layer foil welding;

• The weldment is not energized, no external heating source is required, and micro-porosity and other defects are not present in the joint, brittle intermetallic compounds are not formed, and splashing of molten metal that is easily present during resistance welding does not occur;

• The physical and mechanical properties of the weld metal do not change microscopically. The static load strength and fatigue strength of the welded joint are higher than those of the electric resistance welded joint, and the stability is good;

• The surface oxide film or coating of the metal to be welded has little effect on the welding quality, and the preparation work for the weldment before welding is relatively simple;

• Less power required for welding; less deformation of weldments;

• No need to add any binder, filler or solvent, it has the advantages of simple operation, fast welding speed, high joint strength and high production strength;

Principles of Ultrasonic Welding

    Ultrasonic welding is a solid-phase welding method in which the connection between the weldments is achieved by the high-frequency elastic vibration of the acoustic system and the holding of static pressure between the workpieces. Under the joint action of static pressure and elastic vibration energy, the weldment transforms the elastic vibration energy into friction energy, deformation energy and thermal energy between the workpieces, so that the surface of the two workpieces forms a pure metal fit and atom diffusion, thereby achieving friction welding. The principle is shown below.

    At present, the research on high-power ultrasonic welding of thicker plates (0.8–3.0 mm) is mainly focused on Al and Mg alloy structural parts. High-power ultrasonic welding Cu, Al in lithium battery pole package and other industries is one of the most important research directions.