Advantages and Disadvantages of Common Battery Welding Technologies

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

1. Battery Cell Welding

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

Internal welding of the battery cell includes tab welding, tab and terminal connection, terminal (connector) and top cover welding, top cover periphery welding (seam welding), sealing welding (filler welding), etc.

2. Battery Pack Welding

The welding involved in battery pack assembly includes Terminals to collector plate welding, and collector plate to busbar connections.

3. Welding Technology

The welding requirements for each step in the battery manufacturing process depend on the specific type, size, and capacity of the battery. Typical welding includes tab welding, tab, and terminal welding, end cap perimeter welding, sealing nail welding, terminal and collector board welding, etc.

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

3.1 Ultrasonic Welding

Under greater pressure, ultrasonic vibrations are transmitted to the welded parts. This process does not melt the metal and is a “cold welding”. It is usually used for welding the positive and negative electrode tabs inside the battery cell. The tab material is composed of aluminum foil and copper foil.

3.2 Resistance Welding

Resistance welding is a thermoelectric process. In this process, the electrodes are in contact with the components at a certain pressure, and for a precisely controlled time, an electric current passes through the electrodes and the components, generating heat at the junction of the components. The heat-affected zone is very small and the pressure required for welding is also very small. Suitable for metal welding applications from fine wire to sheet metal parts.

3.3 Micro-TIG

Tungsten inert gas welding (TIG), similar to resistance welding, uses a power source to generate an arc between a tungsten material electrode and the workpiece to generate heat for welding. Micro-TIG welding is a non-contact welding process that produces high-quality welds with minimal heat-affected zones. It is suitable for welding conductive metals and different metals and is the perfect choice for welding small components.

3.4 Laser welding

Lasers provide a high-intensity light source that is focused to a very small diameter and can melt metal quickly. Laser welding is a non-contact welding process suitable for welding joints of various shapes and various materials. Advantages include small heat-affected zones, flexible welding size changes, and high-speed welding.