Apr 02, 2020
Nowadays, the pursuit of energy conservation and emission reduction has been driving the innovation of battery technology, especially the innovation of production technology. Because of its excellent performance, the lithium battery is widely used in electronic products consumption, vehicle, and energy market, and its production technology innovation is particularly important.
The production process of lithium battery is a typical "roll to roll" process, which requires two processing steps: film to a single battery, and single battery assembly into the battery system. A typical lithium battery has three layers of the film - anode film, isolation film, and cathode film, as shown in the figure below.
The thickness of the electrode coating is usually 100 μm, while the isolation film 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:
Because of the high requirements for accuracy, controllability, and the quality of the processing machine, such links as foil slitting, foil cutting, tab cleaning, and separator foil cutting are more suitable for laser processing. Compared with traditional machining, laser machining has the advantages of no tool wear, flexible cutting shape, edge quality control, higher accuracy, and lower operating cost.
According to the design of the battery, a roll of metal foil is cut into thin strips along the long side. The infrared pulse laser is suitable for this part, which can cut the electrode coating with high speed and high quality. If there are more precise requirements for cutting width and quality, pulse green light and ultraviolet light can also be considered.
The cutting process of metal foil refers to cutting the thin strip anode film and cathode film into the required shape according to the design of the battery. Depending on the battery design and whether the foil coil is completely coated, you can choose or adjust the beam to cut the coating or only cut the foil. This link is applicable to the same laser and aluminum foil cutting link.
In certain cases, graphite and lithium metal oxides need to be removed to show bare copper or aluminum foil labels. The key to this step is to remove the coated material without damaging the foil underneath. The pulse infrared laser is most suitable for this link.
Separator foil cutting
Similar to aluminum foil cutting, the covering film should also be cut into the required shape according to the battery design. Because the isolation membrane is composed of organic compounds, the pulsed UV laser is the most suitable choice.