A lithium battery spot welding machine utilizes the resistance heat generated when current flows through the contact surface between electrodes and workpieces. This equipment locally heats lithium battery tabs and cell components (including tab-to-tab connections) to a molten or plasticized state, then applies pressure through electrodes to form a secure welded joint.
The working principle is based on the “resistance heating effect”: When high current (typically thousands to tens of thousands of amperes) passes through the contact point between electrodes and workpieces in milliseconds, the contact resistance and internal resistance of the workpiece convert electrical energy into thermal energy, rapidly raising the temperature of the welding area above the metal’s melting point to form a local fusion core.
Simultaneously, the pressure applied by the electrodes ensures that the molten metal bonds tightly with the surrounding plastic-deformed material, forming a metallurgically bonded weld upon cooling. Throughout the process, three key parameters—welding current, current duration, and electrode pressure—must be precisely matched according to the material type (e.g., copper, aluminum, or composite materials), thickness, and welding requirements of lithium battery tabs to prevent over-welding that could damage the cell or weak welds that compromise connection strength.
The advantages of the lithium battery spot welding machine are mainly reflected in the following aspects:
- Precision-controlled welding quality: The digital control system enables precise adjustment of parameters including current, duration, and pressure, ensuring consistent weld dimensions and strength. This meets the stringent connection reliability requirements of lithium batteries while minimizing risks of false welding and over-welding.
- The heat-affected zone is minimized: millisecond-level brief current application concentrates heat intensely in the welding area while maintaining low temperature rise in adjacent materials, effectively protecting heat-sensitive components like lithium-ion battery cells and separators from thermal degradation or safety hazards.
- High welding efficiency: A single welding cycle typically takes just 0.1-0.5 seconds. When combined with automated feeding or positioning systems, this enables continuous batch processing, significantly boosting the throughput of lithium battery assembly lines.
- The joint strength and conductivity are excellent: the metallurgical bonding of the solder joint has high mechanical strength and good conductivity, which can reduce the internal resistance of the battery, reduce the energy loss in the process of charge and discharge, and improve the cycle life of the battery;
- High adaptability: Compatible with various lithium battery tab materials (e.g., pure copper, nickel-plated copper, aluminum, aluminum-to-nickel transition, etc.) and multiple welding configurations (tab-to-cell, tab-to-tab, tab-to-busbar, etc.), meeting the welding requirements of cylindrical，
- User-friendly and automation-compatible: Modern spot welders feature intuitive human-machine interfaces with easy-to-set parameters, and seamlessly integrate with automated production lines. By employing robots or robotic arms for unmanned welding, they reduce labor costs while ensuring consistent production quality.
- High environmental and safety standards: Unlike arc welding, the process produces no smoke or arc light pollution. With overcurrent/overvoltage protection and anti-caking electrode design, the equipment ensures operational safety, meeting the cleanroom requirements for lithium battery production.
These advantages make the spot welding machine for lithium battery become the core equipment of the manufacturing process of lithium ion battery, which plays an irreplaceable role in ensuring the battery performance, safety and production efficiency.
