CN218996756U

CN218996756U - Pole piece structure and lithium ion battery

Info

Publication number: CN218996756U
Application number: CN202222726208.4U
Authority: CN
Inventors: 黄波; 罗敬; 高云雷; 余志�; 刘关心; 王传宝; 于子龙; 陈杰
Original assignee: Huizhou Liwinon Energy Technology Co Ltd
Current assignee: Huizhou Liwinon Energy Technology Co Ltd
Priority date: 2022-10-17
Filing date: 2022-10-17
Publication date: 2023-05-09
Anticipated expiration: 2032-10-17

Abstract

The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to a pole piece structure and a lithium ion battery, comprising a pole piece body; the nicks are arranged on at least one surface of the pole piece body at intervals; wherein the positions of the scores correspond to the positions of the corners of the battery cells. According to the utility model, the problem of lithium precipitation at the corners of the battery core is solved by optimizing the pole piece structure, so that the service life of the battery is prolonged.

Description

Pole piece structure and lithium ion battery

Technical Field

The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to a pole piece structure and a lithium ion battery.

Background

Nowadays, wearing electronic products such as bluetooth headsets, watches, etc. are increasingly favored and widely used by people. The electronic product for wearing has smaller volume, so the matched battery core has smaller volume. In order to meet the application experience of consumers, the battery cell is continuously developed in the fast charging direction, so that the battery cell with excellent fast charging performance is an important development direction in the future.

After the existing quick-charging battery is charged and discharged at a high rate, lithium precipitation starts to appear at an interface after circulation, so that the circulation attenuation is quick, the endurance and the service life of the battery are affected, and the user experience is reduced.

Disclosure of Invention

The utility model aims at: aiming at the defects in the prior art, the pole piece structure is provided, the problem of lithium precipitation at the corners of the battery core is improved by optimizing the pole piece structure, and the service life of the battery is prolonged.

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

a pole piece structure comprises a pole piece body; the nicks are arranged on at least one surface of the pole piece body at intervals; wherein the positions of the scores correspond to the positions of the corners of the battery cells.

Preferably, a plurality of the scores are arranged at intervals along the length direction of the pole piece body.

Preferably, a plurality of the scores are arranged at intervals along the width direction of the pole piece body.

Preferably, the plurality of scores form a dent line in the width direction of the pole piece body, and the dent line is a continuous line or a discontinuous line.

Preferably, the notch is a single pit or a plurality of pits arranged at intervals.

Preferably, the nicks are symmetrically arranged on two sides of the pole piece body.

Preferably, the score has an outer diameter of 0.1-2mm.

Preferably, the shape of the notch is round, square or bar.

Preferably, the pole piece body comprises a current collector and a coating coated on the surface of the current collector, and the notch is positioned on the surface of the coating.

The utility model has the beneficial effects that the nicks are etched on the surface of the pole piece body, the positions of the nicks correspond to the positions of the corners of the battery cells, namely, the surface of the pole piece is modified, so that the liquid retention amount of electrolyte can be increased, the mobility of the electrolyte is ensured, the lithium precipitation condition at the corners of the battery cells is improved under the condition of ensuring the quick charge of the battery cells, the cyclic attenuation is slowed down, and the service life of the battery cells is prolonged.

Drawings

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

Fig. 1 is a schematic cross-sectional view of a pole piece body according to a first embodiment of the present utility model.

Fig. 2 is a schematic diagram of a corner structure of a battery cell according to a first embodiment of the present utility model.

Fig. 3 is a schematic cross-sectional view of a pole piece body according to a second embodiment of the present utility model.

Fig. 4 is an expanded schematic view of a pole piece body according to a second embodiment of the present utility model.

Fig. 5 is a schematic diagram of a corner structure of a battery cell according to a second embodiment of the present utility model.

Wherein reference numerals are as follows:

1-a pole piece body;

2-scoring; 21-pit;

3-corner;

4-a positive plate;

a 5-separator;

6-a negative plate;

7-electrode lugs;

8-insulating gummed paper;

x-length direction;

y-width direction.

Detailed Description

Certain terms are used throughout the description and claims to refer to particular components. Those of skill in the art will appreciate that a hardware manufacturer may refer to the same component by different names. The description and claims do not take the form of an element differentiated by name, but rather by functionality. As used throughout the specification and claims, the word "comprise" is an open-ended term, and thus should be interpreted to mean "include, but not limited to. By "substantially" is meant that within an acceptable error range, a person skilled in the art can solve the technical problem within a certain error range, substantially achieving 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 utility model, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

The present utility model will be described in further detail with reference to fig. 1 to 5, but the present utility model is not limited thereto.

Embodiment one

The pole piece structure comprises a pole piece body 1; the scores 2 are arranged on at least one surface of the pole piece body 1 at intervals; wherein the position of the score 2 corresponds to the position of the cell corner 3.

Since the existing quick-charging battery starts to generate lithium precipitation at the interface after high-rate charge and discharge and the cycle attenuation is fast, the endurance and the service life of the battery are affected, and the user experience is reduced, therefore, the notch 2 is etched on the surface of the pole piece body 1, the position of the notch 2 corresponds to the position of the corner 3 of the battery cell, namely, the surface of the pole piece is modified, the liquid retention amount of electrolyte can be increased, the mobility of the electrolyte is ensured, the lithium precipitation condition at the position of the corner 3 of the battery cell is improved under the condition of ensuring quick charging of the battery cell, the cycle attenuation is slowed down, and the service life of the battery cell is prolonged.

The pole piece is prepared by stirring, rolling, slitting and flaking, and the pole piece at the corner 3 of the battery cell is accurately positioned by CCD or other detection means during winding, and the pole piece at the corner of the battery cell is etched by using a laser etching module or other etching tool templates such as a ceramic knife, a ceramic flywheel, a steel knife and the like.

In the pole piece structure according to the present utility model, a plurality of scores 2 are provided at intervals along the length direction X of the pole piece body 1. In this embodiment, the length direction X of the pole piece body 1 has six scores 2, and the distance between two adjacent scores 2 can be adjusted according to the position of the actual corner 3 of the battery cell, so that the scores 2 are positioned at the position of the corner 3 of the battery cell 2.

In the pole piece structure according to the utility model, the plurality of nicks 2 are arranged at intervals along the width direction Y of the pole piece body 1, the plurality of nicks 2 form a dent line in the width direction Y of the pole piece body 1, and the dent line is a discontinuous line, namely the discontinuous nicks 2 are adopted, so that excessive etching of cathode powder is avoided, the energy density of a battery cell is influenced, and the pole piece structure is suitable for a thin battery cell.

In the pole piece structure according to the utility model, the notch 2 is a single pit 21, so that the excessive etching of active substances of the pole piece, which affects the energy density of the battery cell, is avoided due to the overlarge area of the notch 2, and the pole piece structure is suitable for a thin battery cell.

In the pole piece structure according to the present utility model, the scores 2 are symmetrically provided on both sides of the pole piece body 1. When the pole piece is wound into a battery core, the scores 2 on the two sides of the pole piece body 1 are positioned in the same direction, and the scores 2 of the pole piece of the outer ring and the scores 2 of the pole piece of the inner ring are positioned at the same corner 3.

In the pole piece structure according to the present utility model, the outer diameter of the score 2 is 0.1-2mm, and in some embodiments, the outer diameter of the score 2 may also be understood as the diameter of the score 2, for example, the outer diameter of the score 2 is 0.1mm, 0.4mm, 0.7mm, 1.0mm, 1.4mm, 1.8mm, 2mm, etc., so that the excessive outer diameter of the score 2, which may cause excessive etching of the active material of the pole piece, affecting the cell energy density, can be avoided.

In the pole piece structure according to the present utility model, the shape of the score 2 is circular, square or bar, but the present utility model is not limited thereto, and the score 2 may take other shapes.

In the pole piece structure according to the present utility model, the pole piece body 1 includes a current collector and a coating layer coated on the surface of the current collector, and the score 2 is located on the surface of the coating layer. In this embodiment, the coating layer includes, but is not limited to, an active material layer, and the precise etching is performed on the preset position of the active material layer through a laser etching process and the like, so as to form the score 2. In addition, the current collector without coating is welded with a tab 7, and the surface of the tab 7 is stuck with insulating adhesive paper 8.

The working principle of the utility model is as follows:

the notch 2 is etched on the surface of the pole piece body 1, the position of the notch 2 corresponds to the position of the corner 3 of the battery cell, namely, the surface of the pole piece is modified, so that the liquid retention amount of electrolyte can be increased, the mobility of the electrolyte is ensured, the lithium precipitation condition at the position of the corner 3 of the battery cell is improved under the condition of ensuring the quick charge of the battery cell, the cyclic attenuation is slowed down, and the service life of the battery cell is prolonged.

Second embodiment

Unlike the first embodiment, the following is: the notch 2 of the present embodiment is a plurality of concave pits 21 arranged at intervals, so that the overall area of the notch 2 can be increased, a larger space is reserved in the battery cell, which is helpful for improving lithium precipitation at the corner 3 of the battery cell, and the notch is suitable for a narrow and thick battery cell, and has a large number of battery cell layers and a small number of internal voids, so that more internal voids are formed by the concave pits 21 arranged at intervals.

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

Embodiment III

Unlike the first embodiment, the following is: the notch line in this embodiment is a continuous line, that is, by forming the continuous notch 2, a larger space can be reserved in the cell, which is helpful for improving lithium precipitation at the cell corner 3, and is suitable for a narrow and thick cell, and the number of cell layers is large, and the internal space is small, so that the space is formed by the continuous notch 2.

Lithium ion battery

The utility model comprises the pole piece structures of the first to third embodiments.

The electrode plate comprises a positive electrode plate 4, a diaphragm 5 and a negative electrode plate 6 which are stacked and wound in sequence, wherein the positive electrode plate 4 or the negative electrode plate 6 is of the electrode plate structure.

The cell may comprise at least two pole pieces which are stacked on each other and have opposite polarities, and the pole pieces having opposite polarities respectively form a positive pole piece 4 of the battery and a negative pole piece 6 of the battery. In order to avoid short circuit between the positive pole piece and the negative pole piece 6, a diaphragm 5 is arranged between every two adjacent pole pieces, and the pole pieces with opposite polarities are electrically isolated through the diaphragm 5. At least one of the pole pieces may be of the pole piece construction of the above embodiment.

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 stacked with each other.

Specifically, the first electrode piece may be the positive electrode piece 4, and the positive electrode piece 4 structure of the above embodiments 1 to 3 is adopted, and the second electrode piece may be the negative electrode piece 6; alternatively, the first pole piece may be the negative pole piece 6 and the second pole piece may be the positive pole piece 4, without limitation.

In some examples, the cells may be coiled cells. The first pole piece, the diaphragm 5 and the second pole piece which are sequentially stacked are wound around the winding center, and a winding structure is formed.

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 staggered and stacked along the same direction, and a diaphragm 5 is arranged between each 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 of the above embodiments will occur to those skilled in the art to which the utility model pertains from the foregoing disclosure and teachings. Therefore, the present utility model is not limited to the above-described embodiments, but is intended to be capable of modification, substitution or variation in light thereof, which will be apparent to those skilled in the art in light of the present teachings. In addition, although specific terms are used in the present specification, these terms are for convenience of description only and do not limit the present utility model in any way.

Claims

1. A pole piece structure, comprising:

a pole piece body (1);

the scores (2) are arranged on at least one surface of the pole piece body (1) at intervals;

wherein the position of the notch (2) corresponds to the position of the cell corner (3).

2. A pole piece structure as claimed in claim 1, wherein: the scores (2) are arranged at intervals along the length direction (X) of the pole piece body (1).

3. A pole piece structure as claimed in claim 2, wherein: the scores (2) are arranged at intervals along the width direction (Y) of the pole piece body (1).

4. A pole piece construction as claimed in claim 3, wherein: the plurality of scores (2) form a dent line in the width direction (Y) of the pole piece body (1), and the dent line is a continuous line or a discontinuous line.

5. A pole piece structure as claimed in claim 1, wherein: the nicks (2) are single pits (21) or a plurality of pits (21) which are arranged at intervals.

6. A pole piece structure as claimed in claim 1, wherein: the nicks (2) are symmetrically arranged on two sides of the pole piece body (1).

7. A pole piece structure as claimed in claim 1, wherein: the external diameter of the nick (2) is 0.1-2mm.

8. A pole piece structure as claimed in claim 1, wherein: the shape of the notch (2) is round, square or bar.

9. A pole piece structure as claimed in claim 1, wherein: the pole piece body (1) comprises a current collector and a coating coated on the surface of the current collector, and the notch (2) is positioned on the surface of the coating.

10. A lithium ion battery, characterized in that: the electrode plate structure comprises a positive electrode plate (4), a diaphragm (5) and a negative electrode plate (6) which are stacked and wound in sequence, wherein the positive electrode plate (4) or the negative electrode plate (6) is of the electrode plate structure according to any one of claims 1-9.