A kind of interspersed electric core and its preparation method and device

Abstract

The invention provides an interspersed battery cell and its preparation method and device. The preparation steps are as follows: stack the upper diaphragm, the negative electrode sheet, the lower diaphragm and the positive electrode sheet sequentially to form a composite layer; lay one end of the composite layer on a slide plate Then lay one end of the positive electrode sheet in the opposite direction above the upper separator in the composite layer; then stack the composite layer on the positive electrode sheet in the direction of the positive electrode sheet; place the composite layer and the positive electrode sheet together in an S shape The structure is stacked to form an interspersed cell. The invention improves the space utilization rate of the electric core, and makes the tension in all parts of the electric core consistent, the pole piece is not easy to break, and the internal reaction will be more uniform. In addition, the strip-shaped positive and negative electrodes and the separator are mechanically stacked, which greatly improves the production efficiency.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to an interspersed battery cell and a preparation method and device thereof. Background technique [0002] The battery cell of lithium-ion battery is composed of positive pole piece, separator, and negative pole piece. At present, the battery core structure is mainly winding type, laminated type, and wound stacked type. [0003] Among them, the winding battery core: because the cross section of the battery core is elliptical, during the charge and discharge of the battery, the expansion and contraction of the electrodes may lead to uneven gaps between the electrodes, resulting in a decrease in battery performance; although the winding type The cell is suitable for cylindrical batteries, but when it is applied to a square aluminum shell battery, there will be defects such as easy breakage of the pole piece at the bend, falling off of the electrode active material, and l...

AI Technical Summary

Problems solved by technology

[0003] Among them, the winding battery core: because the cross section of the battery core is elliptical, during the charge and discharge of the battery, the expansion and contraction of the electrodes may cause uneven gaps between the electrodes, resulting in a decrease in battery performance; although the winding type The battery cell is suitable for cylindrical batteries, but when it is applied to a square aluminum shell battery, there will be defects such as easy breakage of the pole piece at the bend, falling off of the electrode active material, and low space utilization; Inconsistent tension on the side will lead to uneven internal reactions; at the same time, there are disadvantages such as long pole pieces and large internal resistance of the battery, which are not conducive to high-rate charging and discharging.

[0004] Laminated cell: The preparation process of the cell is complicated, requiring a lot of time and energy to perform the sequential stacking process, which is not easy to realize mechanized operation, and the production efficiency is low; both positive and negative electrodes need to be obtained by punching, resulting in edge burrs It is easy to pierce the diaphragm, causing a short circuit inside the battery, and the die-cut pole piece section and material drop are serious, which will also affect the capacity increase of the battery, etc.

[0005] Wound laminated cells: From the winding point, the spacing between the individual electrode assemblies gradually increases along the winding direction, if the bonding of the individual electrode assemblies on the single-side glued adhesive separator is not firm , there will be relative sliding during winding, which will cause the spacing between the single electrode assemblies to be disordered; and each single electrode assembly needs to be arranged in a predetermined direction to ensure the correct stacking sequence of the pole pieces. If the single electrode assembly When the spacing or direction of the battery is set incorrectly, it will lead to poor performance of the final battery

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