Battery pole piece, battery cell and battery

Abstract

The utility model discloses a battery pole piece, a battery cell and a battery. The battery pole piece is provided with an empty foil area and a coating area along the length direction; wherein the initial winding end of the empty foil area is provided with a folding part; the folding part is formed by folding for an odd number of times and comprises a fixed end, a bent part and a free end; and the free end faces the coating area. According to the battery pole piece provided by the invention, the friction force between the diaphragm and the pole piece is improved, so that the diaphragm is prevented from being taken out by the drawn winding needle, the problem of poor core pulling in battery manufacturing in the prior art is solved, and the probability of poor core pulling phenomenon is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery manufacturing technical field, specifically, relate to a kind of battery pole piece, battery and battery. BACKGROUND

[0002] With the development of science and technology and people's attention to environmental protection, battery is widely used in various scenes of life, such as mobile phone, notebook, car and so on, because it has the advantages of green environmental protection, large energy density, high output voltage, small self-discharge and so on. With the development of the times, people's requirements for batteries are getting higher and higher, especially the safety performance of the battery is more urgent.

[0003] In the existing battery manufacturing technology, the battery is composed of battery cells, and the battery cell is composed of positive pole piece, diaphragm and negative pole piece wound and stacked from inside to outside. The foil material near the end of the positive pole piece or negative pole piece, that is, the side close to the winding needle, has a vacant area, that is, a blank metal foil area without active material coating. Therefore, during the winding process, the end will form the innermost circle of the winding core, which does not need to be opposite to the polarity on the other pole piece, so the vacant foil area is longer. The surface of the vacant foil area is smooth, resulting in smaller friction between the diaphragm and the pole piece.

[0004] At present, when making battery cells, the stacked diaphragm and pole piece are usually wound into a core barrel using a winding needle, and then the winding needle is pulled out. However, during the winding process of the battery cell, the pole piece is in direct contact with the winding needle, and there is mirror adsorption or friction between the two. Therefore, when the winding needle is pulled out, if the force between the pole piece and the winding needle is greater than the force between the diaphragm and the pole piece, the pole piece in the inner circle of the winding core is easy to be bent during the pulling out process of the winding needle, which causes the end of the winding core to be irregular, and then the phenomenon of poor core pulling occurs, resulting in unqualified battery cell quality. Once the diaphragm is pulled out, the distance between the two pole ears will be deviated, which will affect the quality of the battery cell and the performance of the battery. UTILITY MODEL CONTENTS

[0005] In order to solve the above technical problems, the utility model discloses a kind of battery pole piece, battery cell and battery, to improve the friction between diaphragm and pole piece, and then reduce the probability of occurrence of poor core pulling phenomenon, improve battery quality.

[0006] To achieve the above purpose, in the first aspect, the utility model discloses a kind of battery pole piece, the pole piece is provided with vacant foil area and coating area;Wherein, the starting winding end of the vacant foil area is provided with folding part;The folding part is formed by folding, including fixed end, bending part and free end;The fixed end is connected with the free end through the bending part;The free end is towards the coating area.

[0007] The utility model discloses a kind of battery pole piece, and the folding part is provided at the end of empty foil area, i.e. close to winding needle. Among them, the folding part is folded and the free end of the folding part is towards the coating area, so that when the winding needle is wound and separated from the pole piece, the free end and fixed end formed by the folding part provide multiple adhesion between the diaphragm and pole piece, and then improve the friction between diaphragm and pole piece to reduce the probability of occurrence of core pulling bad phenomenon, improve battery quality.

[0008] As a preferred example, the inner periphery of the bending part is towards the coating area.

[0009] The utility model sets the inner periphery of the bending part towards the coating area, so that a double-layer structure is formed in the empty foil area of the pole piece by the bending part, and then the adhesion between the pole piece and the diaphragm is improved by the double-layer structure, and then the friction between the diaphragm and the pole piece is improved to reduce the probability of occurrence of core pulling bad phenomenon.

[0010] As a preferred example, the fixed end and the free end form a "∠" shape structure at the bending part.

[0011] The utility model sets the fixed end and the free end form a "∠" shape structure at the bending part, so as to increase the adhesion between the pole piece and the diaphragm by the "∠" shape structure, and then reduce the probability of core pulling bad phenomenon.

[0012] As a preferred example, the free end is provided with an embossed area along the length direction; wherein the embossed area is a region in which the inner side surface of the free end is concave to form a plurality of indentations.

[0013] The utility model sets the embossed area on the inner surface of the free end, i.e. the side surface towards the fixed end, to further improve the friction of the contact surface between the free end and the diaphragm, so as to reduce the probability of occurrence of core pulling bad phenomenon.

[0014] As a preferred example, the length of the free end is 1.2-2.5 mm.

[0015] The utility model sets the length of the free end to be 1.2-2.5 mm, which not only improves the friction between the pole piece and the diaphragm, but also meets the space limitation required for winding the pole piece to form a core, without interfering with the winding of the pole piece.

[0016] As a preferred example, the folding angle α formed by the free end and the fixed end is 0-5 degrees.

[0017] The utility model controls the folding angle formed by the free end and the fixed end to be about 0-5 degrees, so as to form the maximum adhesion between the pole piece and the diaphragm, and as far as possible to reduce the probability of occurrence of core pulling bad phenomenon.

[0018] The second aspect of the utility model discloses a kind of electric core, adopt multiple as described in first aspect battery pole piece winding is made.

[0019] The utility model discloses an electric core, after making by winding needle winding the battery pole piece, in the process of extracting the winding needle, the folding portion provided by the pole piece provides double adhesion between the pole piece and the diaphragm, to improve the friction between the pole piece and the diaphragm, and further reduce the core extraction phenomenon, improve the quality of electric core.

[0020] As a preferred example, the battery pole piece includes a positive pole piece and a negative pole piece; wherein the positive pole piece and the negative pole piece are arranged in sequence with intervals.

[0021] The utility model sets up the battery pole piece includes positive pole piece and negative pole piece, to realize the performance of electric core, satisfy the production demand of electric core.

[0022] As a preferred example, it also includes a diaphragm; wherein the diaphragm is arranged between the positive pole piece and the negative pole piece; the bending portion of the battery pole piece abuts against the diaphragm.

[0023] The utility model sets up the bending portion of the battery pole piece abuts against the diaphragm, to exert pressure between the diaphragm and the pole piece, and further improve the adhesion between the diaphragm and the pole piece by exerting the pressure, reduce the probability of core extraction failure, improve the quality of electric core.

[0024] The third aspect of the utility model discloses a kind of batteries, including the electric core of the second aspect.

[0025] The utility model discloses a kind of batteries, using the electric core formed by pole piece winding with folding portion, based on the electric core according to the folding portion reduces the probability of core extraction failure, and further improve the quality of battery. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a top view structural schematic diagram of a battery pole piece provided by the utility model embodiment;

[0027] Figure 2 It is a side view structural schematic diagram of a battery pole piece provided by the utility model embodiment;

[0028] Figure 3 It is a folding portion structural schematic diagram of a battery pole piece provided by the utility model embodiment;

[0029] Figure 4 It is a free end inner side surface schematic diagram provided by the utility model embodiment;

[0030] Figure 5A top view structure schematic diagram of a battery cell is provided in the embodiment of the utility model;

[0031] Mark explanation: 1, pole piece;11, empty foil area;12, coating area;110, folding part;1101, fixed end;1102, bending part;1103, free end;1104, embossed area;1105, pre-folding angle;2, battery cell;3, diaphragm. DETAILED DESCRIPTION

[0032] The technical scheme in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model.

[0033] The embodiment of the utility model provides a battery pole piece, which prevents the diaphragm from being taken out by the needle by improving the friction between the diaphragm and the pole piece, thereby solving the hand defect problem in the existing technology of battery cell manufacturing, thereby improving the yield of the battery cell and improving the quality of the battery.

[0034] As Figures 1 to 2 shown, a battery pole piece 1 is disclosed in the embodiment of the utility model, which comprises an empty foil area 11 and a coating area 12. Preferably, during the process of winding the battery pole piece 1 to form a battery cell and then forming a battery, the winding direction of the battery pole piece 1 is defined as the length direction, that is, the empty foil area 11 and the coating area 12 are arranged on the battery pole piece 1 in sequence according to the length direction. Further, in order to meet the performance requirements of the battery, the outer surface of the outermost circle of the current collector is not corresponding to the current collector of the other polarity, so that the empty foil area 11 is used as the connection between the pole lug and the current collecting disc in the battery, and the empty foil area 11 is in contact with or close to the needle, which is the starting end of winding and then winding to form a battery cell. One side surface or both side surfaces of the coating area 12 are provided with an active coating layer to realize electron migration and ion exchange through the active coating layer, and the empty foil area 11 is used as the connection between the pole lug and the current collecting disc in the battery.

[0035] Further, in some embodiments of the embodiment, different materials such as copper foil, aluminum foil or copper-aluminum composite foil are used to manufacture the metal empty foil area of the battery pole piece 1 according to different battery manufacturing requirements or process limitations.

[0036] In some embodiments of the present application, in order to avoid the problem of core pulling when the winding needle is pulled out, the adhesion between the electrode tab and the separator can be increased, i.e. the friction between them, to avoid the core pulling phenomenon. Preferably, referring to Figure 1 and Figure 2 , a folding part 110 is added to the empty foil area 11 to achieve a multiple increase in the adhesion between the electrode tab and the separator through the folding part 110, thereby avoiding the problem of core pulling.

[0037] Specifically, referring to Figure 1 , the empty foil area 11 sequentially includes one side edge of the battery electrode tab 1, a free end 1103, a bending part 1102 and a fixed end 1101. The free end 1103 is folded along the bending part 1102 in a direction towards the fixed end 1101, thereby forming a folding part 110 on the empty foil area 11. The free end 1103 is towards the coating area 12.

[0038] Preferably, in some embodiments of the present application, in the case of single folding of the bending part 1102, referring to Figure 2 and Figure 3 , the folding part 110 forms a “∠” shape structure at the bending part 1102. In other embodiments of the present application, based on different winding requirements of the battery cell, the bending part 1102 can be folded multiple times. In the case of other odd number of folding of the bending part 1102, a plurality of free ends 1103, bending parts 1102 and fixed ends 1101 form a continuous “∠” shape structure. Regardless of the number of folding of the folding part 110, the free end 1103 is the outermost edge of the empty foil area 11 and the free end 1103 is towards the inside of the electrode tab 1, i.e. towards the coating area 12.

[0039] Preferably, referring to Figure 3For example, in the case of single folding with the folding part 110, when the free end 1103 and the fixed end 1101 form a "∠" shape structure to increase the friction between the battery pole piece 1 and the diaphragm, in order to ensure that the "∠" shape structure provides the maximum adhesion and does not interfere with the process of winding the battery pole piece 1 to form the battery cell, the friction between the battery pole piece 1 and the diaphragm and the winding of the battery pole piece 1 can be obtained by offline experiments when the "∠" shape structure is at different angles and the free end 1103 is at different lengths. According to the offline experiment, when the pre-folding angle 1105 corresponding to the "∠" shape structure is 0-5 degrees, that is, the folding angle α formed by the free end 1102 and the fixed end 1101 is 0-5 degrees and the length of the free end 1103 is 1.2-2.5 mm, the friction between the battery pole piece 1 and the diaphragm is greater than the friction between the winding needle and the diaphragm and does not affect the winding of the pole piece.

[0040] Preferably, in some embodiments of the present embodiment, when the folding part 110 is used to form the adhesion between the battery pole piece 1 and the diaphragm that is multiple times the adhesion between the winding needle and the diaphragm, in order to further improve the adhesion while meeting the battery performance requirements, that is, meeting the battery requirements that there is no other polarity of the current collector on the outer surface of the current collector on the outermost circle, only the embossed area 1104 is provided on the inner surface of the free end 1103 facing the fixed end 1101. Specifically, referring to Figure 4 , the embossed area 1104 is a region in which the inner surface of the free end 1103 is concave in the length direction or the width direction to form a plurality of indentations. Thus, the adhesion provided by the free end 1103 to the diaphragm is further improved by the indentations. Specifically, when the diaphragm is attached to the hollow foil area 11, the adhesion and friction of the hollow foil area 11 to the diaphragm can be increased by the embossed area 1104. In addition, since the outer surface of the winding needle is smooth, when the winding core is completed and the winding needle is extracted, the friction between the diaphragm and the embossed area 1104, which is basically rough, will be greater than the friction between the diaphragm and the smooth winding needle. In this way, the winding needle can be prevented from causing a connected movement to the diaphragm or the inner circle of the winding core when the core is extracted, and the probability of core extraction failure can be significantly reduced, the yield of the battery cell can be improved, the quality of the battery can be significantly improved by improving the degree of distortion of the diaphragm and the inner circle of the battery cell, and the performance of the battery can be improved.

[0041] It should be noted that in the actual manufacturing process, the indentations in the embossed area 1104 can be formed in many ways and can take many forms, not just as Figure 4One example is shown. Specifically, the embossed area 1104 can be pressed into a pattern with the same or different indentations by stamping, or a pattern can be formed by etched engraving on the embossed area 1104. Further, as shown... Figure 4 As shown, the indentations in the embossing area 1104 are distributed in a parallel structure. This arrangement can improve the space utilization rate of the embossing area 1104. On the basis of regular distribution, increasing the number of indentations can increase the surface roughness of the free end 1103.

[0042] Reference Figure 5 This utility model discloses a battery cell 2, wherein the battery cell 2 adopts the following... Figures 1 to 4 The battery electrode 1 shown in any one of the embodiments is wound together. For example... Figure 5 As shown, the battery electrode 1 is folded along its length from one end, i.e., the starting winding section of the empty foil area 11, to the other end, so that the battery electrode 1 is in the shape of a rolled core. When the folding is completed, the folded portion 110 is at the innermost side of the rolled core, forming the inner circle of the rolled core. Further, in order to ensure that the battery composed of the battery cell 2 can realize the functions of charging and discharging, in some embodiments of this embodiment, the battery electrode used to wind and form the battery cell 2 includes a positive electrode and a negative electrode. The positive electrode is the plate in which the oxidation reaction occurs in the battery, and the negative electrode is the plate in which the reduction reaction occurs in the battery. The positive electrode and the negative electrode are sequentially arranged and connected together by an electrolyte to form the electrochemical reaction region of the battery.

[0043] In some embodiments, when the positive electrode and the negative electrode are arranged alternately and formed into a battery cell 2 by winding, in order to ensure that the current paths of the positive and negative electrodes of the battery cell 2 are connected, a separator 3 is provided between the positive electrode and the negative electrode for isolation, so that the separator 3 can play the role of electronic insulation and provide microporous channels for ion migration between the positive and negative electrodes.

[0044] It should be noted that a battery cell can be formed not only by winding individual positive and negative electrodes, but also by winding multiple battery electrodes 1 that simultaneously have both positive and negative sides. The separator 3 is located between two adjacent electrodes 1, with one side of the separator 3 contacting the negative side of the electrode 1 and the other side contacting the positive side of the electrode 1. Specifically, the separator 3 can be made of a material impregnated with a solid electrolyte to provide ion conduction channels.

[0045] The structure of the positive and negative poles of the battery pole piece 1 and the diaphragm 3 realizes the ion conduction between the positive and negative poles, and prevents direct electrode contact to ensure the normal operation of the battery. The diaphragm 3 plays a role of ion-selective permeation, allowing ions between the positive and negative poles to move in the solid-state electrolyte to maintain the charge and discharge reaction of the battery.

[0046] In some embodiments, with reference to Figure 5 When the battery pole piece 1 and the diaphragm 3 are stacked to form the battery pole piece 1, in order to improve the friction between the battery pole piece 1 and the diaphragm 3, the bending part 101 of the battery pole piece 1 is arranged to abut the diaphragm 3 to apply pressure on the diaphragm 3 and the inner winding surface of the battery pole piece 1, thereby improving the adhesion between the battery pole piece 1 and the diaphragm 3 by the pressure.

[0047] It should be noted that when a single battery pole piece 1 with positive and negative sides is used to wind the battery pole piece 1 to form the battery pole piece 1, the diaphragm 3 simultaneously contacts the positive and negative sides of the battery pole piece 1, and when winding, the diaphragm 3 is located between the two adjacent battery pole pieces 1 inside the battery pole piece 2, that is, to improve the adhesion between the diaphragm 3 and the battery pole piece 1, the bending part 101 of the battery pole piece 1 still abuts the diaphragm 3, that is, the inner winding side of the battery pole piece 2.

[0048] The embodiment of the present application also provides a battery provided with the battery pole piece 1. Figure 5 The battery provided by the embodiment has increased friction between the battery pole piece blank foil area 11 and the winding needle, and the battery pole piece significantly reduces the core pulling defect during the manufacturing process of the battery, effectively solves the core pulling defect problem, improves the yield of the battery pole piece, and improves the quality and performance of the battery. The derivation process of the beneficial effects is basically the same as the derivation process of the above-mentioned battery pole piece, which will not be repeated here.

[0049] In summary, the battery pole piece with a folding part in the blank foil area is used in the present application. The strength of the multi-layer foil formed in the folding part is higher than that of a single layer, and the diaphragm will not be pulled out to cause core pulling and shaking during needle pulling, thereby improving the adhesion between the battery pole piece and the diaphragm, and further reducing the probability of core pulling. Further, in the process of winding the battery pole piece to form the battery pole piece, the folding part of the battery pole piece abuts the diaphragm to apply pressure between the diaphragm and the battery pole piece, and further improve the friction between the diaphragm and the battery pole piece by the pressure, thereby reducing the probability of core pulling and improving the quality of the battery pole piece and the battery.

[0050] The above-described specific embodiments have further detailed the purposes, technical solutions and beneficial effects of the present application, and it should be understood that the above-described is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. It is particularly pointed out that, for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A battery pole piece, characterized by, The pole piece is provided with an empty foil area and a coating area; wherein a folding part is arranged on the starting winding end of the empty foil area; the folding part is formed by folding and comprises a fixed end, a bending part and a free end; the fixed end is connected with the free end through the bending part; the free end faces the coating area.

2. The battery pole piece of claim 1, wherein, The inner periphery of the bending part faces the coating area.

3. The battery electrode of claim 2, wherein, The fixed end and the free end form a "∠" shape structure at the bending part.

4. The battery pole piece of claim 1, wherein, The free end is provided with an embossed area along the length direction; wherein the embossed area is a region of the inner side surface of the free end which is concave to form a plurality of indentations.

5. The battery pole piece of claim 1, wherein, The length of the free end is 1.2-2.5 mm.

6. The battery electrode of claim 3, wherein, The folding angle α formed by the free end and the fixed end is 0-5 degrees.

7. An electric cell characterized by A plurality of the battery pole pieces as claimed in any one of claims 1-6 are wound to form.

8. An electric cell according to claim 7, wherein The battery pole piece comprises a positive pole piece and a negative pole piece; wherein the positive pole piece and the negative pole piece are arranged in sequence and at intervals.

9. An electric cell according to claim 8, wherein Further comprising a separator; wherein the separator is arranged between the positive pole piece and the negative pole piece; the bending part of the battery pole piece abuts against the separator.

10. A battery, characterized by An electric core comprising the battery pole piece as claimed in any one of claims 7-9.

Images