CN218414632U

CN218414632U - Cathode plate structure and lithium ion battery

Info

Publication number: CN218414632U
Application number: CN202222312539.3U
Authority: CN
Inventors: 项海标
Original assignee: Huizhou Liwinon Energy Technology Co Ltd
Current assignee: Huizhou Liwinon Energy Technology Co Ltd
Priority date: 2022-08-30
Filing date: 2022-08-30
Publication date: 2023-01-31
Anticipated expiration: 2032-08-30

Abstract

The utility model belongs to the technical field of the battery manufacture, concretely relates to negative pole piece structure and lithium ion battery, including the pole piece body, the pole piece body includes: a current collector; a first particulate coating applied to at least one side of the current collector; a second particle coating layer coated on the surface of the first particle coating layer; wherein the particle diameter of the first particle coating is greater than the particle diameter of the second particle coating. The utility model discloses an optimize the pole piece structure, can compromise the compaction density and the security of pole piece, help improving the quality of battery.

Description

Cathode plate structure and lithium ion battery

Technical Field

The utility model belongs to the technical field of battery manufacture, concretely relates to negative pole piece structure and lithium ion battery.

Background

The lithium ion battery as a novel secondary battery has the advantages of large energy density and power density, high working voltage, light weight, small volume, long cycle life, good safety, environmental protection and the like, and has wide application prospect in the aspects of portable electric appliances, electric tools, large-scale energy storage, electric traffic power supplies and the like.

The lithium ion battery generally comprises a cathode sheet, an anode sheet, a separation film, an electrolyte and an aluminum plastic film. The existing structure is that a layer of safety coating is coated on an aluminum foil, and the compacted density of a cathode plate is improved by replacing a binder in slurry, but the safety performance is poor.

SUMMERY OF THE UTILITY MODEL

One of the purposes of the utility model lies in: aiming at the defects of the prior art, the cathode plate structure is provided, the compaction density and the safety of the cathode plate can be considered by optimizing the cathode plate structure, and the quality of a battery is improved.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

a cathode sheet structure comprising a sheet body, the sheet body comprising: a current collector; a first particulate coating applied to at least one side of the current collector; a second particle coating applied to a surface of the first particle coating; wherein the particle diameter of the first particle coating is greater than the particle diameter of the second particle coating.

Preferably, both sides of the current collector are provided with the first particle coating layer and the second particle coating layer.

Preferably, the first particle coating is a lithium iron phosphate material, a ternary material or a lithium manganate material.

Preferably, the second particulate coating layer is a cathode active material.

Preferably, the current collector is a metal foil.

Preferably, the pole piece body is provided with a central area and an edge area, the second particle coating layer is exposed on the surface of the central area of the pole piece body, and the current collector is exposed on the surface of the edge area of the pole piece body.

Preferably, the projection of the first particle coating on one side of the current collector partially overlaps the projection of the first particle coating on the other side of the current collector.

Preferably, the area of the first particle coating is equal to or greater than the area of the second particle coating.

Preferably, the thickness of the first particle coating layer is greater than or equal to the thickness of the second particle coating layer.

The second objective of the present invention is to provide a lithium ion battery, which includes the above cathode plate structure.

The beneficial effects of the utility model reside in that, the utility model discloses a structure of double-deck coating, first granule coating adopt the lithium iron phosphate of big granule as the primary coat, and lithium iron phosphate can be when acupuncture or heavy object impact test, can reduce the probability of positive pole graphite and aluminium foil contact, helps improving the security of battery, and second granule coating adopts the small particle cathode material, can guarantee that the energy density loss of battery is less, and in addition, first granule coating and the cooperation of second granule coating can compromise and promote compaction density and energy density. The utility model discloses an optimize the pole piece structure, can compromise the compaction density and the security of pole piece, help improving the quality of battery.

Drawings

Features, advantages and technical effects of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of the present invention.

Wherein the reference numerals are as follows:

10-a current collector;

1-a first particle coating;

2-second particle coating.

Detailed Description

As some terms are used throughout the description and claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect.

Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the present application, unless otherwise explicitly stated or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

The present invention will be described in further detail with reference to fig. 1, but the present invention is not limited thereto.

Implementation mode one

The following describes embodiment one with reference to fig. 1

The cathode plate structure comprises a pole piece body, and the pole piece body comprises: a current collector 10; a first particle coating layer 1 coated on at least one side of the current collector 10; a second particle coating layer 2 coated on the surface of the first particle coating layer 1; wherein the particle diameter of the first particle coating 1 is larger than the particle diameter of the second particle coating 2.

Because the current structure is that a layer of safety coating coats on the aluminium foil, promote the compaction density of cathode plate through the binder in the replacement thick liquids, but the security performance is relatively poor, therefore, adopt the structure of double-deck coating, first granule coating 1 adopts large-grained lithium iron phosphate as the primary coat, lithium iron phosphate can be when acupuncture or heavy object impact test, can reduce the probability of positive pole graphite and aluminium foil contact, help improving the security of battery, second granule coating 2 adopts the small granule cathode material, can guarantee that the energy density loss of battery is less, in addition, first granule coating 1 and the cooperation of second granule coating 2, can compromise promotion compaction density and energy density.

In the cathode plate structure according to the present invention, the two surfaces of the current collector 10 are both provided with the first particle coating 1 and the second particle coating 2. In this embodiment, the first particle coatings 1 on both sides of the current collector 10 are symmetrically disposed, and the second particle coatings 2 on both sides of the current collector 10 are also symmetrically disposed, but the present invention is not limited thereto, and in some embodiments, the first particle coatings 1 or the second particle coatings 2 on both sides of the current collector 10 may be staggered structures or partially overlapped in the thickness direction.

In the cathode plate structure according to the present invention, the first particle coating layer 1 is made of lithium iron phosphate material, and the second particle coating layer 2 is made of cathode active material. The cathode active material includes, but is not limited to, lithium cobaltate, and may also be one or a combination of more of LiCoO2, liNiO2, liVO2, liCrO2, liMn2O4, liCoMnO4, li2NiMn3O8, lini0.5mn1.5o4, liCoPO4, liMnPO4, liFePO4, liNiPO4, liCoFSO4, cuS2, feS2, moS2, niS, tiS2, and the like. The cathode active material may be further modified by a modification method known to those skilled in the art, for example, the cathode active material may be modified by coating, doping, etc., and the material used in the modification method may be one or a combination of more of Al, B, P, zr, si, ti, ge, sn, mg, ce, W, etc., but is not limited thereto. While current collector 10 is generally a structure or part that collects current, current collector 10 may be any of a variety of materials known in the art as suitable for use as a lithium ion battery current collector 10.

According to the utility model discloses an among the negative pole piece structure, mass flow body 10 is the metal foil. The current collector 10 may be, but is not limited to, a metal foil or the like, and more particularly, may be, but is not limited to, an aluminum foil or the like.

According to the utility model discloses an among the negative pole piece structure, the pole piece body is provided with center and marginal zone, and second particle coating 2 exposes in the center surface of pole piece body, and mass flow body 10 exposes in the marginal zone surface of pole piece body.

In the cathode sheet structure according to the present invention, the projection of the first particle coating 1 on one side of the current collector 10 partially overlaps the projection of the first particle coating 1 on the other side of the current collector 10, in this embodiment, the first particle coatings 1 on both sides of the current collector 10 completely overlap, but in some embodiments, the first particle coatings 1 on both sides of the current collector 10 may also partially overlap.

In the cathode sheet structure according to the present invention, the area of the first particle coating layer 1 is greater than or equal to the area of the second particle coating layer 2, and the thickness of the first particle coating layer 1 is greater than or equal to the thickness of the second particle coating layer 2, but the present invention is not limited thereto, and the area and the thickness of the first particle coating layer 1 and the second particle coating layer 2 can be adjusted according to the structure of the actual battery, and is not limited herein.

The utility model discloses a theory of operation is:

adopt the structure of double-deck coating, first granule coating 1 adopts the lithium iron phosphate of big granule as the primary coat, and lithium iron phosphate can be when acupuncture or heavy object impact test, can reduce the probability of anode graphite and aluminium foil contact, helps improving the security of battery, and second granule coating 2 adopts the granule cathode material, can guarantee that the energy density loss of battery is less, in addition, first granule coating 1 and the cooperation of second granule coating 2 can compromise and promote compaction density and energy density.

Second embodiment

The difference from the first embodiment is that: the first particle coating 1 of the present embodiment is a ternary material. In this embodiment, the first particle coating 1 is made of a ternary material with large particles, the second particle coating 2 is made of a cathode material with small particles, and the first particle coating 1 is used as a base coat, so that the safety performance can be improved, and the matching of the large particles and the small particles of the pole piece can improve the compaction density and the energy density.

Other structures are the same as those of the first embodiment, and are not described herein again.

Third embodiment

The difference from the first embodiment is that: the first particle coat layer 1 of the present embodiment is a lithium manganate material. In this embodiment, first granule coating 1 adopts the lithium manganate material of big granule, and second granule coating 2 adopts the granule cathode material, and first granule coating 1 can improve the security performance as the primary coat, and simultaneously, the collocation of the big or small granule of pole piece can compromise and promote compaction density and energy density.

Lithium ion battery

The utility model comprises a first to a third cathode plate structure.

Specifically, the battery cell comprises a battery cell, and the battery cell may comprise at least two pole pieces which are stacked on each other and have opposite polarities, and the pole pieces with opposite polarities form a cathode piece of the battery and an anode piece of the battery respectively. In order to avoid short circuit between the cathode sheet and the anode sheet, a diaphragm is arranged between every two adjacent pole pieces, and the pole pieces with opposite polarities are electrically isolated by the diaphragm. At least one of the pole pieces may be the pole piece in the above embodiments.

The at least two pole pieces may include a first pole piece and a second pole piece, the polarities of the first pole piece and the second pole piece are opposite, and the first pole piece and the second pole piece are overlapped with each other.

Specifically, the first pole piece may be a cathode piece, and the second pole piece may be an anode piece; alternatively, the first pole piece may be an anode piece, and the second pole piece may be a cathode piece, which is not limited herein.

In some examples, the cells may be wound cells. The first pole piece, the diaphragm and the second pole piece which are sequentially stacked are wound around a winding center to form a winding structure.

In other examples, the cells may be laminated cells. The first pole pieces are multiple, the second pole pieces are multiple, the first pole pieces and the second pole pieces are sequentially arranged in a staggered and stacked mode along the same direction, and a diaphragm is arranged between every two adjacent first pole pieces and second pole pieces, so that the first pole pieces and the second pole pieces are electrically insulated.

Variations and modifications to the above-described embodiments may become apparent to those skilled in the art from the disclosure and teachings of the above description. Therefore, the present invention is not limited to the above-mentioned embodiments, and any obvious modifications, replacements or variations made by those skilled in the art on the basis of the present invention belong to the protection scope of the present invention. Furthermore, although specific terms are employed herein, such terms are used for convenience of description and are not to be construed as limiting the invention in any way.

Claims

1. The utility model provides a negative pole piece structure which characterized in that, includes the pole piece body, the pole piece body includes:

a current collector (10);

a first particulate coating (1) applied on at least one side of said current collector (10);

a second particle coating (2) applied to the surface of the first particle coating (1);

wherein the particle diameter of the first particle coating (1) is larger than the particle diameter of the second particle coating (2).

2. The cathode sheet structure of claim 1, wherein: both sides of the current collector (10) are provided with the first particle coating (1) and the second particle coating (2).

3. The cathode sheet structure of claim 1, wherein: the first particle coating (1) is made of a lithium iron phosphate material, a ternary material or a lithium manganate material.

4. The cathode sheet structure of claim 1, wherein: the second particle coating layer (2) is a cathode active material.

5. The cathode sheet structure of claim 1, wherein: the current collector (10) is made of metal foil.

6. The cathode sheet structure of claim 1, wherein: the pole piece body is provided with a central area and an edge area, the second particle coating (2) is exposed on the surface of the central area of the pole piece body, and the current collector (10) is exposed on the surface of the edge area of the pole piece body.

7. The cathode sheet structure of claim 1, wherein: the projection of the first particle coating (1) on one surface of the current collector (10) is overlapped with the projection part of the first particle coating (1) on the other surface of the current collector (10).

8. The cathode sheet structure of claim 1, wherein: the area of the first particle coating layer (1) is larger than or equal to the area of the second particle coating layer (2).

9. The cathode sheet structure of claim 1, wherein: the thickness of the first particle coating layer (1) is greater than or equal to that of the second particle coating layer (2).

10. A lithium ion battery, characterized by: comprising the cathode sheet structure of any one of claims 1 to 9.