Battery Pack Welding: Tips for Improving Tab-to-Terminal Connections
Modern battery packs come in various configurations, including cylindrical, prismatic, ultra-capacitor, and pouch types, each requiring specific welding approaches.
How would we manage without battery packs? Whether it's powering our latest portable electronic devices, power tools, or hybrid/electric vehicles, removable CNC technology are essential to daily life. A critical aspect of battery pack production is the tab-to-terminal connection, a key welding application. To meet the high standards of quality and production, manufacturers require equipment, systems, and automated lines that can deliver consistently reliable results. Both resistance welding and laser welding technologies offer excellent solutions, whether used as standalone units or integrated into fully automated production lines.
Battery Pack Manufacturing Systems for Welding Tabs to Terminals
Modern battery packs come in various configurations, including cylindrical, prismatic, ultra-capacitor, and pouch types, each requiring specific welding approaches. A key step in battery pack production is joining individual batteries using a collector plate with tabs that connect to both the positive and negative terminals. Additionally, some packs require a smaller number of connections between the collector plate and the bussbar.
Selecting the right welding technology for battery tabs involves several important factors, such as the materials being joined, the joint geometry, weld accessibility, cycle time, and budget. It's also essential to consider the overall manufacturing flow and production requirements to ensure efficiency and quality in the welding process.
Fiber Laser Welding
The laser welding process is non-contact, requires no consumables, and enables instantaneous welding once the laser is positioned at the desired weld point. This technology allows for precise control and optimization of weld size and location, ensuring optimal strength and conductivity. Additionally, motion options can be customized to suit the specific manufacturing environment.
Fiber lasers are versatile and can weld battery tabs for prismatic, cylindrical, pouch, and ultra-capacitor battery types. Tab thickness can range from 0.006 to 0.08 inches for both aluminum and copper materials, depending on the battery size. Fiber lasers are capable of welding various material combinations, including aluminum to aluminum, aluminum to steel, copper to steel, and copper to aluminum. The figure above illustrates examples of fiber laser welding for common dissimilar material combinations in tab-to-terminal connections.
Resistance Welding
Resistance welding is the most cost-effective method for welding battery tabs, utilizing both DC inverter closed-loop and capacitor discharge power supplies. This technique features fast rise times, closed-loop feedback control, polarity switching, and options for displacement and force sensing, allowing for precise tuning and monitoring to ensure high quality and yield.
Resistance welding is particularly effective for welding nickel tab materials up to 0.015 inches thick, as well as nickel or steel-clad copper tab materials up to around 0.012 inches thick to various terminal materials. For nickel tab thicknesses up to 0.007 inches, tabs can be welded directly without modification. However, for thicker tabs, it is advisable to incorporate slots and projections during the stamping process to prevent electrical shunting and minimize electrode wear.
So Which Technology Is Best for My Application?
|
Technology |
Key Benefits |
Battery Pack Applications |
|
Laser |
Non-contact |
Cylindrical, prismatic, pouch, ultra-capacitor |
|
Resistance welding |
Closed loop feedback welding |
Cylindrical, small prismatic |
Complete Production Solution for Efficient Product Flow
A variety of system solutions are available for battery pack manufacturing, each designed to facilitate optimal product flow. It is essential to consider how the pack is loaded and unloaded, how un-welded parts are secured before and during the welding process, and the extent to which the system reports data to supervisory control software. The following elements must be included:
- Enclosures
- Motion
- Tooling (for laser welding only)
- Communication
- Process Monitoring
