Method for preparing porous copper foil current collector of lithium battery

Abstract

The embodiment of the invention discloses a method for preparing a porous copper foil current collector of a lithium battery, and relates to the technical field of lithium battery preparation. The method comprises the following steps: S1, pretreating a copper foil; S2, machining multiple holes in the copper foil in a laser machining mode; S3, carrying out post-treatment on the copper foil; S4, coating two sides of the copper foil with the electrode slurry; S5, drying the copper foil coated with the electrode slurry in a drying oven; and S6, performing rolling and slitting treatment on the dried copper foil to obtain a lithium battery electrode plate. According to the method, on the premise that the mechanical strength of the foil is guaranteed, the invalid quality of the copper foil current collector is reduced, the conductivity is improved, the adhesive force between the copper foil current collector and a negative active material composite film is enhanced, and the technical effectsof effectively improving the mechanical stability, the overall specific capacity, the rapid charging and discharging capacity and the long-term cycle life of the lithium battery electrode are achieved.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a method for preparing a lithium battery porous copper foil current collector. Background technique [0002] Facing the world's increasingly scarce energy crisis and increasingly severe environmental pollution, lithium batteries have shown great technical potential and broad market prospects in the field of efficient and environmentally friendly energy storage. They are used in portable electronic devices, electric tools, electric transportation (including electric vehicles and Bicycles), medical health, aerospace, military defense, smart grid and power station energy storage and other fields have a wide range of applications. Especially with the gradual promulgation of regulations to stop the sale of fuel vehicles globally, the new energy electric vehicle market will further show explosive growth, becoming a strategic plan for the development of governments of various ...

AI Technical Summary

Problems solved by technology

Most lithium batteries fail due to the shedding of electrode active materials during use.

According to the existing copper foil and coating technology, when the negative electrode active material such as graphite is coated on the copper foil, the contact area between the rigid copper foil and the active material particles is limited, and the interface resistance is large, resulting in an increase in the internal resistance of the battery. Large, affecting the performance of lithium battery such as high current charge and discharge

At the same time, the rigid planar copper foil has poor adhesion to active material particles, conductive agents, and binders. During long-term continuous charging and discharging, deformation and peeling between the active material and the copper foil collector are prone to occur, resulting in battery failure. The internal resistance is further increased, which reduces the battery capacity, shortens the cycle life, and deteriorates the safety

In addition, the copper foil current collector itself occupies about 15% of the weight of the battery, but it cannot store lithium ions like active materials such as graphite, resulting in a decrease in the specific capacity and specific energy of the lithium battery.

[0005] Therefore, the volume change of the negative electrode of the lithium battery during charging and discharging is very easy to cause the electrode to be brittle and pulverized, causing the active material to fall off from the copper foil collector, the capacity is reduced, the electrical contact is reduced, and the impedance is increased.

At the same time, due to the interaction between the active material and the electrolyte, the cracks and pulverized areas are the starting sites for the degradation of the chemical stability of the electrode, which reduces the effective active material of the lithium battery, and deteriorates the safety performance, rate performance and cycle stability.

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