Rolling method and device for battery pole piece

Abstract

The invention relates to rolling method and device for a battery pole piece. The rolling method comprises twice rolling process, wherein a foil is not added in primary rolling; secondary rolling adopts a rolling method with addition of a foil; and the rolling method in secondary rolling comprises the following steps: an upper foil piece, a lower foil piece and a pole piece with the two surfaces coating with powder simultaneously penetrate through a space between a upper roll and a lower roll, and the upper roll and the lower roll respectively roll the pole piece through the upper foil piece and the lower foil piece, wherein the upper foil piece and the lower foil piece are arranged on the upper and lower surfaces of the pole piece respectively. The rolling device comprises a rack, the upper roll, the lower roll, a pole piece releasing roll, a pole piece retracting roll, an upper foil piece releasing roll, an upper foil piece retracting roll, a lower foil piece releasing roll and a lower foil piece retracting roll. According to the rolling method and device, during secondary rolling, the upper roll and the lower roll apply pressure to the two surfaces of the pole piece through the upper foil piece and the lower foil piece respectively to ensure particle intervals of the pole piece in vertical direction to be uniform and a battery manufactured thereby to be difficult in powder dropping phenomenon occurrence in the charging and discharging process and particularly in the later period of circulation and improve the electrochemical performance and the using safety of the battery.

Description

technical field [0001] The invention relates to the technical field of manufacturing lithium-ion batteries, in particular to a battery pole piece rolling method and a rolling device. Background technique [0002] As a new type of green, high-energy and environmentally friendly power battery, lithium-ion battery has a series of advantages such as no memory effect, high working voltage, long cycle life, fast charge and discharge, wide temperature range and less pollution, and has been widely used in It is widely used in mobile phones, notebook computers, electric vehicles and other fields. [0003] Lithium-ion batteries are composed of positive electrodes, negative electrodes, electrolytes, and separators, and each part is composed of complex and different components. For example, the negative electrode contains graphite, conductive agent, binder, and copper foil, etc., and it needs to be homogenized in the middle , Rolling and other complex processes. In fact, lithium-ion b...

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Problems solved by technology

[0005] The present invention mainly solves the problem that the upper and lower rolls directly contact the powder bonded on both sides of the pole piece when the original battery pole piece is rolled, and pressure is applied, resulting in uneven particle spacing in the vertical direction of the pole piece, and the battery is charged and discharged. During the process, especially in the late stage of the cycle, the powder is prone to fall off, which leads to the deterioration of the electrochemical performance of the battery, and there are technical problems of potential safety hazards; a method for rolling the battery pole piece is provided. The powder on both sides of the sheet is not in direct contact, but pressure is applied through the foils on both sides of the pole piece to ensure that the particle spacing in the vertical direction of the pole piece is even, so that the battery is not prone to powder falling off during the charging and discharging process, especially at the end of the cycle, improving the battery life. Electrochemical performance, but also improve the safety of battery use

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