Negative plate and battery

Abstract

The invention provides a negative plate and a battery. The invention provides a negative electrode plate, the negative electrode plate comprises a negative electrode current collector and a negative electrode active layer arranged on at least one surface of the negative electrode current collector, and in the width direction of the negative electrode active layer, the negative electrode active layer comprises a first negative electrode active layer located in the middle and second negative electrode active layers located on the two sides of the first negative electrode active layer; the symmetry axis of the first negative active layer is overlapped with the symmetry axis of the negative plate; the liquid absorption capacity of the first negative electrode active layer is greater than that of the second negative electrode active layer, and / or the electrolyte consumption of the first negative electrode active layer is less than that of the second negative electrode active layer. According to the negative plate provided by the invention, the problem of insufficient electrolyte infiltration in the middle area of the negative plate is effectively relieved, the problem of lithium precipitation of the negative plate is relieved, and the cycle performance of the battery is improved.

Description

Technical field [0001] The present invention relates to a negative electrode sheet and a battery, relates to the field of battery technology. Background [0002] Because of its high cycle life, light and thin, the battery is widely used in mobile phones, notebook computers, power tools, wearable and other fields. With the development of technology, the energy density of the battery has put forward higher and higher demand, and the energy density of the battery can be improved by increasing the compaction density of the negative electrode sheet, for example, the compaction density of the negative electrode sheet is from 1.7g / cm 3 Increased to 1.78g / cm 3 The energy density of the battery can be increased by 2%-4%. [0003] However, with the improvement of the compaction density of the negative electrode sheet, the porosity of the negative electrode sheet will be reduced, and the electrolyte is mainly through the path channel on the upper and lower sides of the cell to achieve infil...

AI Technical Summary

Problems solved by technology

[0003] However, as the compaction density of the negative electrode sheet increases, the porosity of the negative electrode sheet will decrease, and the electrolyte mainly infiltrates the negative electrode sheet through the path channels on the upper and lower sides of the cell, and the lower porosity It will hinder the infiltration channel of the electrolyte, resulting in insufficient infiltration of the electrolyte in the middle area of ​​the negative electrode sheet. As the number of cycles increases, the electrolyte solution is gradually consumed, which is not enough to support the normal charge and discharge needs, resulting in the appearance of the negative electrode sheet in the middle area. Lithium is precipitated in a spot shape, and the precipitated lithium ions have a large safety hazard. At the same time, the precipitated lithium ions will have a side reaction with the electrolyte, resulting in abnormal pitting in the middle area, which affects the cycle performance of the battery.

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