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A positive pole piece and a lithium ion battery including the positive pole piece

A technology for positive pole pieces and positive current collectors, applied in the direction of positive electrodes, battery electrodes, circuits, etc., can solve problems such as poor safety performance, hidden safety hazards, and poor battery safety performance, and achieve safety improvements, interface problems, and excellent The effect of cycle performance

Active Publication Date: 2022-04-22
ZHUHAI COSMX BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In recent years, the development of volume energy density and mass energy density of digital lithium-ion batteries has almost reached the limit of materials. Due to the poor safety performance of high-voltage lithium cobaltate (≥4.4V) and high-nickel materials, the safety performance of the corresponding batteries Performance deteriorates, and lithium-ion batteries use flammable organic solvents as electrolyte solvents, which poses safety hazards

Method used

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  • A positive pole piece and a lithium ion battery including the positive pole piece
  • A positive pole piece and a lithium ion battery including the positive pole piece
  • A positive pole piece and a lithium ion battery including the positive pole piece

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] (1) The positive electrode active material lithium iron phosphate (D 50 <3μm), the conductive agent SP and the binder 5130 glue are mixed at a weight ratio of 86%:4%:10%, and the mixture is dispersed in NMP, and the safety layer slurry is obtained after double planetary stirring. The safety layer slurry was coated on the front and back sides of an aluminum foil current collector with a thickness of 12 μm, dried after coating, and the thickness of the coating layer on one side was 5 μm, to obtain a positive electrode sheet containing a safety layer.

[0056] (2) PVDF and carbon nanotubes are mixed at a weight ratio of 40%:60%, and the mixture is dispersed in NMP, and the conductive layer slurry is obtained after stirring by double planets. The conductive layer slurry is coated on the surface of the positive electrode sheet containing the safety layer, and dried after coating. The thickness of the coating layer on one side is 2 μm, and the positive electrode sheet contain...

Embodiment 2

[0073] The preparation method of embodiment 2 is the same as embodiment 1, except that step (2):

[0074] (2) PVDF and SP are mixed in a weight ratio of 35%:65%, the mixture is dispersed in NMP, and the conductive layer slurry is obtained after double planetary stirring. The conductive layer slurry was coated on the surface of the positive electrode sheet containing the safety layer, dried after coating, and the coating thickness on one side was 2 μm, so as to obtain the positive electrode sheet containing the conductive layer and the safety layer.

Embodiment 3-8

[0088] The preparation method of Examples 3-8 is the same as that of Example 1, except that the selection and additives of the first conductive agent, the first binder, and the first positive electrode active material in step (1) are different, as shown in Table 2.1. Show.

[0089] Table 2.1 The composition of the positive electrode sheet of Example 1, 3-8 and Comparative Example 2-3

[0090]

[0091] Table 2.2 Lithium-ion battery performance test results of Examples 1, 3-8 and Comparative Examples 2-3

[0092]

[0093]As can be seen from Table 2.2, the types of positive active materials in the safety layer in the positive electrode sheet with the three-layer structure of the present invention are different, and there is a large difference in the safety performance of lithium-ion batteries. Through comparative studies, it is found that safe The positive electrode active material in the layer is in the charging voltage range of 2.5V to 4.3V and the charging rate of 0.2C,...

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Abstract

The invention provides a lithium ion battery positive electrode sheet and a preparation method thereof, the positive electrode sheet includes a positive electrode current collector, a safety layer, a conductive layer and an active material layer, and the conductive layer includes a second conductive agent and a second binder agent; through the use of a new multi-layer coating pole piece structure design, it has safer and better cycle performance than the current conventional two-layer coating structure pole piece; using multi-layer coating technology, taking advantage of the high conductivity of the conductive layer It can improve the interface problem caused by the poor electronic conductivity of the safety layer and the active material layer in the positive electrode sheet during the cycle, so as to ensure the safety of the high energy density lithium-ion battery and further improve the cycle performance of the lithium-ion battery and The problem of the large change rate of DCIR growth during the cycle.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a positive pole piece and a lithium ion battery including the positive pole piece. Background technique [0002] Power batteries and high-voltage digital batteries are currently developing rapidly, and are widely used in 3C consumer digital fields such as mobile phones, notebook computers, tablet computers, and small Bluetooth batteries and electric vehicles. Whether it is digital or power fields, the requirements for the safety performance of lithium-ion batteries are getting higher and higher. In recent years, the development of volume energy density and mass energy density of digital lithium-ion batteries has almost reached the limit of materials. Due to the poor safety performance of high-voltage lithium cobaltate (≥4.4V) and high-nickel materials, the safety performance of the corresponding batteries Performance deteriorates, and lithium-ion batter...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/131H01M4/36H01M4/505H01M4/525H01M4/62H01M4/02
CPCH01M4/131H01M4/366H01M4/505H01M4/525H01M4/62H01M2004/028H01M2004/021Y02E60/10
Inventor 曾家江樊亚楠伍鹏李素丽
Owner ZHUHAI COSMX BATTERY CO LTD