A lithium battery winding device and winding process

Abstract

The invention provides a lithium battery winding device and a winding process. The winding device includes an unwinding mechanism, a roller passing mechanism and a winding mechanism. The winding device also includes a lamination and lamination mechanism. The unwinding The mechanism is used to unwind the positive electrode sheet, separator and negative electrode sheet at the same time, and the roller passing mechanism is used to transport the positive electrode sheet, separator and negative electrode sheet from the unwinding mechanism to the lamination lamination mechanism; the lamination lamination The mechanism is used to sequentially stack and laminate the positive electrode sheet, separator and negative electrode sheet; the winding mechanism is used to wind the laminated positive electrode sheet, separator and negative electrode sheet. The invention avoids adjusting the position of the positive / negative electrode sheet and the separator in the winding mechanism by laminating the position of the positive / negative electrode sheet and the separator, and can shorten the transmission channel of lithium ions in the working process of the finished battery , so as to improve the product rate performance, reduce internal resistance and other performance.

Description

technical field [0001] The invention relates to the field of lithium batteries, in particular to a lithium battery winding device and a winding process. Background technique [0002] With the development of lithium-ion batteries, its process technology has also been continuously optimized and improved. At present, the manufacture of lithium-ion batteries (including power batteries and 3C product lithium batteries) is mainly divided into winding process and lamination process from the perspective of process differences. The winding process is mainly used in 3C target products lithium-ion batteries and square aluminum case power batteries; the lamination process is mainly used in soft pack power batteries. [0003] see figure 1 and figure 2 , figure 1 For the existing lithium battery winding manufacturing process flow chart, figure 2 It is the winding principle diagram of the existing winding manufacturing process. During the winding process of lithium-ion batteries, i...

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Problems solved by technology

like figure 1 and figure 2 As shown, since the positive electrode sheet, the negative electrode sheet, and the separator are separated from each other, during the winding process of the existing winding process, the positive electrode roll 11, the separator roll 12, the negative electrode sheet roll 13 and the separator roll in the separated state 12 is simultaneously transported to the winding mechanism 3 by the unwinding mechanism 1 and the roller passing mechanism 2 for winding. The existing winding process is not easy to control the separated positive electrode sheet, separator and negative electrode sheet, and it is prone to deflection. In addition, the air bubbles between the positive electrode sheet and the separator and the negative electrode sheet and the separator are not easy to discharge, resulting in short circuit, size and other defects. On the one hand, the production efficiency will be reduced, on the other hand, it will also be scrapped and increase the manufacturing cost.

In addition, the existing winding process is mainly applied to battery products with hard shells (such as aluminum shells, steel shells, plastic shells, etc.), therefore, the existing winding process has certain limitations in the entire industry

[0004] see image 3 , image 3 It is a flow chart of the manufacturing process of lithium battery stacks in the prior art, such as image 3 As shown, since the positive electrode, separator, and negative electrode are separated from each other, the existing lamination process is to grab the electrode from the positive / negative electrode box and place it on the separator through the interval of the manipulator. The lamination process needs precise control Lamination size, and the existing lamination method has the following defects in the process of stacking: (1) The positive electrode sheet, separator and negative electrode sheet are in a separated state, and no adhesion is formed, and the upper and lower layers are prone to Misalignment, resulting in abnormalities such as short circuit or diaphragm folds; (2) The hardness of the battery cells made by the existing lamination method cannot meet the requirements, which leads to the difficulty of inserting the battery cells into the shell during assembly; (3) The existing The stacking method, air enters between the positive electrode sheet and the separator and the negative electrode sheet and the separator, and the air bubbles in the product are not easy to discharge during the subsequent exhaust, which increases the complexity of the process and also increases the production cost.

At present, the stacking or stacking process in the industry is mainly used in the production of soft-pack lithium batteries. Due to the special structure of soft-pack batteries, no subsequent winding process is required after the positive electrode sheet, separator and negative electrode sheet are stacked. Therefore, the existing The lamination or lamination process has certain limitations throughout the industry

[0005] In addition, since the positive electrode sheet, the separator and the negative electrode sheet are separated from each other, after the hard-shell battery or the soft-pack battery is wound or stacked using the above-mentioned existing winding process or lamination process, the positive electrode sheet, the separator, and the negative electrode The bonding effect between the sheet and the separator is poor, and the transmission channel of lithium ions is lengthened during the charging and discharging process of the finished battery, resulting in poor charging and discharging effect

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