Graded calendering molding method of prelithiation anode

Abstract

The invention discloses a graded calendering molding method of a prelithiation anode. The graded calendering molding method comprises the steps that: a graded calendering lithium foil method is employed, the primary calendering of a lithium strip at pre-pressing rollers is completed, release films are introduced between main pressing rollers to assist in the secondary calendering of the lithium strip to form a lithium foil, and finally, on the release films attached at the fast roller sides of the main pressing rollers, the prelithiation anode is prepared through rolling of composite rollers and recombination of a negative pole piece under the transfer printing effect of the release films so that the large-scale production of the prelithiation anode is achieved, the production is low and the graded calendering molding method is safe and reliable.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a step-by-step calendering forming method of a pre-lithium negative electrode. Background technique [0002] In recent years, with the large-scale application of lithium-ion new energy batteries, lithium-ion battery technology has been vigorously developed, especially the energy density and power density of power lithium-ion batteries for new energy vehicles have been continuously improved. Negative electrode and electrolyte materials have been developed and applied. [0003] The low Coulombic efficiency for the first time is one of the main reasons that limit the application of some new materials; during the first charging and discharging process of lithium-ion batteries, a large amount of electrolyte will be consumed and the lithium ions released from the positive electrode material will suffer irreversible capacity loss, resulting in lower The Coulombic efficiency, ...

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Problems solved by technology

[0005] The traditional calendering lithium foil process generally adopts one-step calendering in place, without pre-pressing steps, lithium is a very soft alkaline metal, and lithium strip is a coil with a certain width and thickness, and the width meets the requirements. At the same time, in order to ensure that the processing thickness will be thicker, this is due to the difficulty in the production process and high cost of the wide and thin lithium strip; while the production of lithium-ion battery pre-lithium pole pieces requires a certain width of lithium foil, 1mm It is currently a relatively stable thickness of the lithium strip, and the processing width and cost can meet the requirements; and then the 1mm thick lithium strip is directly rolled to less than 10μm, and the deformation of the lithium will exceed 100-200 times, which is very difficult to control. Quality is also difficult to guarantee

[0006] To sum up, the current method of pre-lithium calendering lithium foil composite negative electrode has high requirements on raw materials, and the lithium ribbon should not be too thick. The thickness and uniformity of the lithium foil obtained by calendering are poor, and the thin lithium foil The high price is not conducive to industrial production. How to enhance the control of the thickness and uniformity of the pre-lithium lithium foil and reduce the cost is of great significance

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