Method for ultrasonic welding of copper thin plate and nickel thin plate

Abstract

The invention discloses a method for ultrasonic welding of a copper thin plate and a nickel thin plate. The method comprises the steps that the portion between the to-be-welded copper thin plate and the to-be-welded nickel thin plate is coated with nano nickel formate particles to form a middle layer with the thickness of 15-45 microns; before the middle layer is coated, the copper thin plate andthe nickel thin plate are immersed in a dilute hydrochloric acid solution with the concentration of 4.5%-8.8% to be washed for 5-10 minutes, and then the middle layer is cleaned with pure alcohol andair-dried; and the copper thin plate and the nickel thin plate coated with the nano nickel formate particles as the middle layer are subjected to ultrasonic welding for 0.20-0.75 seconds at the welding pressure of 30-60 psi, wherein the welding amplitude is 25-55 microns. According to the method, the nano nickel formate particles are used as the middle layer to assist ultrasonic welding of the copper thin plate and the nickel thin plate, the maximum shearing strength can reach 2898 N, the joint resistance is less than 102 microhm, the mechanical property and conductive performance of a joint are improved, and the requirement of the automobile power battery industry for ultrasonic welding of copper / nickel joints can be met.

Description

technical field [0001] The invention relates to the field of welding technology, in particular to a method for ultrasonically welding a copper thin plate and a nickel thin plate. Background technique [0002] Copper and nickel can be used as conductor materials for automotive power batteries and battery packs, so there is inevitably a welded joint between copper sheets and nickel sheets. As conductor materials, copper sheets and nickel sheets have specific grain sizes and grain orientations, so During the welding process, try not to damage the specific structure of the base metal. Although the commonly used welding methods such as electron beam welding, plasma welding, and laser welding can weld copper sheets and nickel sheets, these methods will melt the base metal, causing the grain size of the weld and heat-affected zone to grow. Orientation changes, which will lead to a decrease in the electrical conductivity and mechanical properties of the copper / nickel joint. How to ...

AI Technical Summary

Problems solved by technology

Although the commonly used welding methods such as electron beam welding, plasma welding, and laser welding can weld copper sheets and nickel sheets, these methods will melt the base metal, causing the grain size of the weld and heat-affected zone to grow. Orientation changes, which will lead to a decrease in the electrical conductivity and mechanical properties of the copper / nickel joint. How to weld the copper sheet to the nickel sheet without substantially changing the grain size and grain orientation of the base material is a difficult problem

[0003] Ultrasonic welding has the advantages of short welding time and low welding energy, and is now widely used in welding copper sheets and nickel sheets. However, due to the specific tooth pattern on the surface of the welding head of the ultrasonic metal welding machine, it is easy to cause a gap between the tines. An unwelded area will be produced at the welding interface below the part, which will affect the electrical conductivity and mechanical properties of the joint; therefore, it is urgent to adopt a welding method that can increase the welding area of ​​the ultrasonic welding copper sheet / nickel sheet interface