Application | Application of Laser Processing in Lithium Battery Production

Compared with traditional mechanical processing, laser processing has the advantages of no tool wear, flexible cutting shapes, edge quality control, higher accuracy and lower operating costs.

Because of its excellent performance, lithium batteries are widely used in the consumer electronics, motor vehicles and energy markets, and its production technology innovation is particularly important.

The production step of lithium battery is a typical "roll-to-roll" process, which requires two processing steps-thin film to single battery, and single battery assembly into a battery system. A typical lithium battery has three films-anode film, separator film and cathode film, as shown in the figure below.

The electrode coating thickness is usually 100 μm, while the separator is 50 μm. The anode film is a copper film coated with graphite, the cathode film is an aluminum film coated with lithium metal oxide, and the isolation film is composed of polypropylene and polyethylene. Lithium battery production process:

Due to the high requirements for accuracy, controllability and quality of processing machines, foil slitting, foil cutting, tab cleaning and separator foil cutting, etc. The link is more suitable for laser processing. Compared with traditional mechanical processing, laser processing has the advantages of no tool wear, flexible cutting shapes, edge quality control, higher accuracy and lower operating costs.

Foil slitting

The metal foil slitting process refers to cutting a roll of metal foil into thin strips along the long side according to the design of the battery. The infrared pulse laser is suitable for this link, which can slit the electrode coating with high speed and high quality. If there are more precise requirements for slitting width and quality, pulsed green light and ultraviolet light can also be considered.

Foil cutting

The metal foil cutting process refers to cutting the elongated anode film and cathode film into the required shape with reference to the design of the battery. Depending on the battery design and whether the metal foil roll is completely coated, you can choose or adjust the beam to cut the coating or only cut the metal foil. The laser applicable to this link is the same as the aluminum foil slitting link.

Tab cleaning

Under certain circumstances, graphite and lithium metal oxide need to be removed to reveal bare copper or aluminum foil labels. The key to this step is to remove the coating material without damaging the metal foil below it. Pulsed infrared lasers are most suitable for this link.

Separator foil cutting

Similar to aluminum foil cutting, the cover film should also be cut into the required shape with reference to the battery design. Because the isolation film is composed of organic compounds, pulsed ultraviolet lasers are the most suitable choice.