Do you know which laser applications are used in the battery manufacturing process?

2023-06-20

Do you know which laser applications are used in battery production?

In recent years, electric vehicles and related industries have gained increasing attention and are gradually becoming the direction of automotive development, thanks to breakthroughs in lithium-ion battery technology. While lithium-ion battery manufacturing is already mature in the smartphone industry, battery manufacturers must now adapt their processes to meet the growing demand for EVs while ensuring battery quality and stability. Laser processing has become a key technology here—laser cutting, welding, and marking have already entered the production lines of the battery industry.
The diagram below shows the manufacturing process of a battery. Raw materials such as aluminum foil or copper foil are coated and compressed into electrode foils, then cut into electrode shapes—copper foil for the anode and aluminum foil for the cathode. These electrode sheets are then welded together in lap joints, including copper-to-copper, aluminum-to-aluminum, and even copper-to-aluminum—an engineering challenge. Next, the electrode sheets are enclosed in a shell to form a cell. At this stage, sealing the housing is required, followed by electrolyte injection. Since the electrodes are already inside the shell, welding must be performed with minimal heat input to avoid internal damage. Finally, multiple cells are assembled into battery modules or packs, where electrodes are welded together to form conductive paths.

▲ Lithium-ion battery manufacturing process. Image source: [https://ieeexplore.ieee.org/](https://ieeexplore.ieee.org/)

\[Electrode Foil Cutting]
Foils must be cut into electrodes with smooth edges—no burrs or particles—and the coated layer must remain intact without scratches or cracks, making this a very delicate step. Some manufacturers require cutting speeds of over 50 m/min for high productivity. To achieve such high precision and speed, mechanical cutting can suffer from tool wear and deformation. Laser cutting is the optimal solution. As a non-contact method, laser cutting ensures minimal chip loss, low deformation (mechanical or thermal), and smooth cuts, enabling flexible processing and high throughput.

▲ Comparison of cut quality among three cutting methods. Image source: moldmakingtechnology.com

\[Electrode Welding]
Electrodes made of copper and aluminum foils must be joined by lap welding. This includes copper-to-copper, aluminum-to-aluminum, or copper-to-aluminum joints. These must be free of pores or cracks, and maintain low electrical resistance to prevent energy loss. Aluminum is difficult to weld due to oxidation and reactivity; copper-aluminum joints tend to form brittle compounds, risking joint failure. Laser welding is the best solution for electrode lap welding. Galvo-based fiber lasers achieve welding speeds of hundreds to thousands of mm/s, delivering fast and precise results. Pulsed lasers reduce heat input, minimizing deformation and brittle compound formation, while providing adequate strength and low resistance. The weld path can also be linear or wobble to increase width.

▲ Appearance and cross-section of aluminum-copper laser lap weld. Image source: Jumbo Laser

\[Battery Shell Welding]
The battery cell shell must be sealed, requiring high-quality welds with low heat input to protect internal components. Laser welding is ideal—producing narrow, smooth, strong welds with stable power and consistent depth. Properly controlled laser power prevents burn-through, protecting internal structures. Using galvo laser heads, multiple welds can be completed in seconds without axis movement, boosting efficiency.

\[Battery Module Interconnection Assembly]
The final step involves assembling cells into modules or packs. Busbars are used to connect electrodes, and galvo laser welding excels here. It minimizes spatter during copper busbar welding and achieves pore-free joints. Galvo systems can customize weld paths in circular or curved patterns.

▲ Laser welded busbars with custom weld paths. Image source: M. F. R. Zwicker, Journal of Advanced Joining Processes

\[Laser Marking for Production Traceability]
Just like many manufactured products, batteries require traceability markings. Laser marking is ideal—it’s permanent, tamper-resistant, and can operate standalone or integrate with the production line.

▲ Laser marking for battery traceability. Image source: Jumbo Laser

Recommended Reading:
Boost Production Efficiency! Laser Welding Machine Advantages Explained

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