What are the battery welding technologies？

1. Cell welding

Batteries have become an integral part of everyday life, powering an increasing number of portable devices such as electronic devices, cordless power tools, energy storage, hybrid and electric vehicles.

Common battery pack cells include cylindrical cells, square aluminum cells, soft pack cells and supercapacitors.

Welding inside the battery cell includes: tab welding, tab to terminal connections, terminal (connecting piece) and top cover welding, seam welding around the top cover, and fill port welding. As shown in Figure 1.

Figure 1 Common battery cell types Source AMADA

2. Battery pack welding

The current battery pack configuration is shown in Figure 2.

Figure 2 Common Battery Pack Configurations Source AMADA

Battery pack assembly involves welding: positive and negative terminals to collector plate welding, collector plate to busbar connections.

3. Welding Technology

The welding requirements for each part of the battery manufacturing process depend on the specific type, size and capacity of the battery. Typical welding are: welding of lugs, welding of lugs and terminals, welding around the end caps, welding of sealing nails, welding of terminals and collector plates.

For each step of the welding process, there are several welding techniques that can be considered: Resistance Welding, Ultrasonic Welding, Micro-TIG Welding, Laser Welding. Which one to use usually depends on the specific type of welding required and the production requirements.

3.1 Ultrasonic welding

Ultrasonic vibrations are transmitted to the parts under high pressure, creating a connection with a "fabric" like texture. This process does not melt metal and is a "cold weld". It is commonly used for welding the positive and negative lug bands inside the cell, where the lug material consists of aluminum and copper foil.

3.2 Resistance Welding

Resistance welding is a thermoelectric process. In this process, an electrode touches the part with a certain pressure and an electric current passes through the electrode and the part for a precisely controlled period of time, generating heat at the joint of the parts. The heat affected zone is very small and the pressure required to weld is minimal. Suitable for metal welding applications ranging from fine wire to sheet metal parts.

3.3 Micro-TIG

Tungsten inert gas welding (TIG), similar to resistance welding, utilizes a power source to generate an arc between a tungsten material electrode and the workpiece, which generates heat for welding.Micro-TIG welding is a non-contact welding process that produces high-quality weld seams with a minimized heat-affected zone. Suitable for conductive metals, as well as welding between dissimilar metals, it is perfect for welding small components.

3.4 Laser welding

is a relatively new technology that entered the manufacturing market only in the mid-1980s. Lasers provide a high-intensity light source that focuses very small diameters to rapidly melt metal. Laser welding is a non-contact welding process suitable for welding joints of various shapes and in a wide range of materials. Advantages include a small heat affected zone, flexibility in weld size, and high speed welding.