CN213660452U

CN213660452U - Secondary battery

Info

Publication number: CN213660452U
Application number: CN202022236329.1U
Authority: CN
Inventors: 朱伯礼; 鄢翔; 于子龙; 杨山; 陈杰; 李载波
Original assignee: Huizhou Liwinon Energy Technology Co Ltd
Current assignee: Huizhou Liwinon Energy Technology Co Ltd
Priority date: 2020-10-10
Filing date: 2020-10-10
Publication date: 2021-07-09
Anticipated expiration: 2030-10-10

Abstract

The utility model provides a secondary battery, which comprises a first pole piece, a second pole piece with the polarity opposite to that of the first pole piece and high-temperature protective glue; the first pole piece is provided with a first pole lug; the second pole piece is provided with a second pole lug; the heat-resistant temperature of the high-temperature protective adhesive is more than or equal to 300 ℃; the first pole lug is arranged in an active material coating area of the first pole piece; the surface of the first pole lug is covered with high-temperature protection glue, and/or the position of the second pole piece opposite to the first pole lug is covered with high-temperature protection glue. Compared with the prior art, the utility model discloses a high temperature protection is glued and is replaced conventional protection to glue and cover and setting up in the utmost point ear in active material coating district, and this high temperature protection is glued and is not melted in 300 ℃, not serious shrink deformation, still can play good guard action to the utmost point ear for the battery is when short circuit test or accidental contact short circuit outside, has avoided this utmost point ear to melt protection because of the high temperature and has glued and the diaphragm, causes the situation of inside short circuit, has widened the application of putting winding structure in utmost point ear.

Description

Secondary battery

Technical Field

The utility model relates to a lithium cell field, concretely relates to secondary battery.

Background

In the current mobile phone market, mobile phones tend to be designed to be wide, large and thin, a large-screen mobile phone needs higher battery capacity and higher energy density to ensure cruising ability, and the higher battery capacity and the higher energy density mean longer charging time and greater safety risk. In order to meet the good experience of using a mobile phone of a client, the lithium battery of the mobile phone replaces the battery cell of the traditional head tab winding structure with the battery cell of the tab middle winding structure, so that the charging speed is accelerated, and the charging temperature rise is reduced; the capacity density is improved by using a thinner diaphragm and protective adhesive paper so as to increase the energy density of the battery and improve the endurance; at present, the battery with the winding structure in the middle of the pole lug has mass production products on a small number of high-end mobile phones in the mobile phone market, and the battery with the winding structure in the middle of the pole lug is a great trend of application of mobile phone batteries based on the advantages of the battery with a new structure.

The cell of the winding structure arranged in the lug middle of the lithium battery of the mobile phone replaces the cell of the traditional head lug winding structure, but the structural safety risk still exists, particularly the position of the positive lug, the impedance of the positive lug is maximum when external short circuit, overcharge and thermal shock tests are tested, the temperature is highest, and the risk is also maximum; in the traditional head tab winding structure, the anode tab is welded in the head empty foil area of the anode sheet, the inward-folding contraposition contact is the anode during winding, and the risk of contact short circuit between the position of the anode tab and the cathode is small; the winding structure is arranged in the tab, the anode tab is arranged in the coating area of the pole piece, and the temperature of the anode tab is too high to break the protective glue and the diaphragm during external short circuit test, so that the contact internal short circuit of the anode tab and the cathode piece is caused, and the risk of thermal runaway is increased. Based on the defect, the application of the winding structure in the middle of the pole lug is greatly limited.

In view of the above, it is necessary to provide a technical solution to the above problems.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a: the secondary battery solves the problem that a pole lug is easy to break a diaphragm at high temperature to cause internal short circuit when the battery is subjected to external short circuit test or accidental contact short circuit at present.

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

a secondary battery comprising:

the first pole piece is provided with a first tab;

the second pole piece is opposite to the first pole piece in polarity; a second tab is arranged;

high-temperature protective glue, the heat-resisting temperature is more than or equal to 300 ℃;

the first pole lug is arranged in an active material coating area of the first pole piece; the surface of the first pole lug is covered with the high-temperature protection glue, and/or the position of the second pole piece opposite to the first pole lug is covered with the high-temperature protection glue.

Preferably, the surface which is not provided with the first tab is the surface a of the first pole piece, and the surface a of the first pole piece is also covered with the high-temperature protection glue at the position opposite to the first tab. Correspondingly, the surface provided with the first tab is the surface B of the first pole piece.

Preferably, the high-temperature protection glue is arranged on the surfaces A of the second pole piece and the first pole piece corresponding to the position of the first pole lug.

Preferably, the high-temperature protection glue comprises a first high-temperature protection glue and a second high-temperature protection glue, the first high-temperature protection glue covers the surface of the first tab, and the second high-temperature protection glue covers the position of the second pole piece opposite to the first tab.

Preferably, the first high-temperature protective adhesive is further covered with at least part of the active material coating region.

Preferably, the width of the second high-temperature protection glue is larger than that of the first high-temperature protection glue; the length of the second high-temperature protection glue is larger than that of the first high-temperature protection glue.

Preferably, the width of the second high-temperature protection glue is at least 6mm greater than that of the first high-temperature protection glue; the length of the second high-temperature protection glue is at least 3mm greater than that of the first high-temperature protection glue.

Preferably, the second pole piece is arranged on the active material coating area of the second pole piece; the surface of the second electrode lug is covered with the high-temperature protection glue, and/or the position of the first electrode piece opposite to the second electrode lug is covered with the high-temperature protection glue.

Preferably, the first pole piece is an anode piece, the second pole piece is a cathode piece, the first tab is an anode tab, and the second tab is a cathode tab; the anode tab is arranged in an active material coating area of the anode sheet, and the two surfaces of the anode sheet at the corresponding position of the anode tab are covered with the high-temperature protection glue.

Preferably, the secondary battery further comprises a protective adhesive having a heat-resistant temperature of less than 300 ℃; the cathode lug is arranged in an active substance coating area of the cathode sheet or a head empty foil area of the cathode sheet, and the surface of the cathode lug is covered with the high-temperature protection glue or the protection glue.

Compared with the prior art, the beneficial effects of the utility model reside in that: the utility model discloses a high temperature protection is glued and is replaced conventional protection to glue and cover and setting up in the utmost point ear in active material coating district, and this high temperature protection is glued and is not melted in 300 ℃, not serious contraction deformation, still can play good guard action to utmost point ear for the battery is when short circuit test or unexpected contact short circuit outside, has avoided this utmost point ear to melt the protection because of the high temperature and has glued and the diaphragm, causes the situation of inside short circuit, has widened the application of putting winding structure in utmost point ear.

Drawings

Fig. 1 is a top view of a pole piece of the present invention.

Fig. 2 is a cross-sectional view of a pole piece of the present invention.

Fig. 3 is a top view of another pole piece of the present invention.

Fig. 4 is a cross-sectional view of another pole piece of the present invention.

Fig. 5 is a schematic diagram of the electric core of the present invention.

Fig. 6 is an enlarged view of a in fig. 5.

In the figure: 1-a first pole piece; 11-a first tab; 2-a second pole piece; 21-a second tab; 3-high temperature protective glue; 31-first high temperature protective glue; 32-second high temperature protective glue; 4-a membrane.

Detailed Description

In order to make the technical solutions and advantages of the present invention clearer, the present invention and its advantageous effects will be described in further detail below with reference to the accompanying drawings of the detailed description and the specification, but the present invention is not limited thereto.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "mounted," "connected," and "fixed" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The utility model discloses the standard part that uses all can purchase from the market, and dysmorphism piece all can be customized according to the description with the record of drawing of description, and the concrete connection mode of each part all adopts conventional means such as ripe bolt, rivet, welding among the prior art, and machinery, part and equipment all adopt prior art, and conventional model, including circuit connection adopts conventional connection mode among the prior art, does not detailed here again.

As shown in fig. 1 to 6, a secondary battery includes a first pole piece 1, a second pole piece 2 having a polarity opposite to that of the first pole piece 1, and a high temperature protective adhesive 3; the first pole piece 1 is provided with a first pole lug 11; the second pole piece 2 is provided with a second pole lug 21; the heat-resistant temperature of the high-temperature protective adhesive 3 is more than or equal to 300 ℃; wherein, the first tab 11 is arranged in the active material coating area of the first pole piece 1; the surface of the first pole lug 11 is covered with high-temperature protection glue 3, and/or the position of the second pole lug 2 opposite to the first pole lug 11 is covered with high-temperature protection glue 3. The specific material adopted by the high-temperature protection glue 3 is not limited too much, as long as the heat-resistant temperature of the material is greater than or equal to 300 ℃, and the material is ensured not to be fused due to the high temperature of the tab within 300 ℃, so as to achieve the purpose of improving the safety performance of the battery.

Namely, the utility model at least comprises three setting modes, one mode is that the surface of the first pole ear 11 cancels the traditional setting of the protective glue and directly covers the high temperature protective glue 3 for protection; secondly, the surface of the first pole lug 11 is reserved with the covering arrangement of the traditional protective glue, and the arrangement of the high-temperature protective glue 3 is added at the position of the second pole piece 2 opposite to the first pole lug 11 so as to play a role in strengthening protection; and the third is to directly arrange the high-temperature protection glue 3 on the surface of the first pole lug 11 and also to increase the arrangement of the high-temperature protection glue 3 at the position of the second pole piece 2 opposite to the first pole lug 11. The first tab 11 and/or the second tab 21 may be disposed at any position of the active material coating region, and preferably, the first tab 11 and/or the second tab 21 is disposed in the middle region of the active material coating region. The tab led out from the middle area can accelerate the charging speed, reduce the charging temperature rise and has higher application value.

Further, the surface without the first tab 11 is used as the surface a of the first pole piece 1, and the surface a of the first pole piece 1 is covered with the high-temperature protective adhesive 3 at a position opposite to the first tab 11. Correspondingly, the surface provided with the first tab 11 is the surface B of the first pole piece 1.

Furthermore, the second pole piece 2 and the surface a of the first pole piece 1 are provided with high temperature protection glue 3 at the position of the first pole tab 11. The design of the two layers of high-temperature protective glue 3 can further ensure the stability of the pole lug and reduce the risk of thermal runaway.

Further, the high-temperature protection glue 3 comprises a first high-temperature protection glue 31 and a second high-temperature protection glue 32, the first high-temperature protection glue 31 covers the surface of the first tab 11, and the second high-temperature protection glue 32 covers the position of the second tab 2 opposite to the first tab 11. The material of the first high temperature protective glue 31 can be the same as the material of the second high temperature protective glue 32.

Further, the first high-temperature protective glue 31 is also covered with at least a part of the active material coating region. So as to ensure that the partial pole ear is completely covered by the first high-temperature protection glue 31, and further improve the safety performance of the battery.

Further, the width of the second high temperature protection glue 32 is greater than the width of the first high temperature protection glue 31; the length of the second high temperature protection paste 32 is greater than that of the first high temperature protection paste 31. Preferably, the width of the second high temperature protection paste 32 is at least 6mm greater than the width of the first high temperature protection paste 31; the length of the second high temperature protection paste 32 is at least 3mm greater than the length of the first high temperature protection paste 31. The second high-temperature protective adhesive 32 is set to have a larger width, so that the risk that lithium ions separated from the corresponding pole piece 2 by the second high-temperature protective adhesive exceed the acceptance of the corresponding position of the pole piece 1, and the lithium separation of the pole piece 1 is caused can be avoided.

Further, a second tab 21 is provided at the active material coated region of the second pole piece 2; the surface of the second tab 21 is covered with a high temperature protective adhesive 3, and/or the position of the first pole piece 1 opposite to the second tab 21 is covered with the high temperature protective adhesive 3. Namely, when two positive and negative electrode lugs are arranged on the active material coating area of the corresponding electrode plate, the surfaces of the two electrode lugs are covered with high-temperature protection glue 3, the other electrode plate at the opposite position of the electrode lugs is also covered with the high-temperature protection glue 3, and the stability of the electrode lugs is further ensured and the risk of thermal runaway is reduced by the design of the two layers of high-temperature protection glue 3.

In the preferred embodiment of the present invention, the first electrode plate 1 is an anode plate, the second electrode plate 2 is a cathode plate, the first tab 11 is an anode tab, and the second tab 21 is a cathode tab; the anode tab is arranged in an active material coating area of the anode sheet, and two surfaces of the anode sheet corresponding to the anode tab are covered with first high-temperature protective glue 31; the cathode lug is arranged in an active material coating area of the cathode sheet or a head empty foil area of the cathode sheet, and two sides of the cathode sheet at the corresponding position of the cathode lug are covered with first high-temperature protective glue 31 or protective glue with heat-resistant temperature less than 300 ℃. In addition, still be provided with two second high temperature protection glues 32 on the active coating district of negative pole piece, after the positive pole piece twined into electric core with the negative pole piece, two second high temperature protection glues 32 on the negative pole piece correspond the setting with two first high temperature protection glues 31 on the positive pole piece, have covered two-layer high temperature protection on the assurance positive pole ear and have glued 3, use dual high temperature protection and glue 3, the positive pole ear can't melt the high temperature protection and glue 3, can't form the short circuit with the negative pole piece to the maximum security performance that improves the battery. Similarly, when the cathode tab is also disposed on the active material coating area of the cathode sheet, two second high temperature protection glues 32 or protection glues with heat resistance temperature less than 300 ℃ can be disposed on the active material coating area of the anode sheet, and after winding, the two second high temperature protection glues 32 on the anode sheet and the two protection glues on the cathode sheet are disposed correspondingly to ensure the stability of the cathode tab.

The preparation method of the secondary battery is described by taking the first pole piece 1 as an anode piece and the second pole piece 2 as a cathode piece, and comprises the following steps:

(1) coating an anode active substance in an anode sheet, and removing part of the anode active substance by at least one method of laser cleaning, solvent removal and the like to form an anode lug groove position for welding an anode lug, wherein the size of the anode lug groove position can be set according to actual production requirements without excessive limitation, and the method of laser welding or ultrasonic welding can be adopted for welding the anode lug;

(2) after the welding of the anode tab is completed, arranging first high-temperature protective glue 31 on both sides of the anode tab position of the anode sheet, wherein the protective glue can be directly adhered to the anode tab position, the adhered area is preferably covered with the anode tab slot position, at least one part of anode active substances can be properly extended and covered, the length of the covered anode active substances can be more than 1mm, and the shape of the first high-temperature protective glue 31 can be determined according to the shape of the anode tab slot position; completing the preparation of the anode sheet;

(3) coating a cathode active substance in the cathode sheet, and removing part of the cathode active substance by at least one method of laser cleaning, solvent removal and the like to form a cathode lug groove for welding a cathode lug, wherein the size of the cathode lug groove can be set according to the actual production requirement without excessive limitation, and the cathode lug can be welded by a laser welding or ultrasonic welding method; of course, the cathode lug can also be arranged in the empty foil area of the head part of the cathode sheet;

(4) after the welding of the cathode lug is completed, arranging first high-temperature protective glue 31 or protective glue with heat resistance temperature less than 300 ℃ on both sides of the cathode sheet and the cathode lug, wherein the protective glue can be directly pasted on the cathode sheet, the pasted area is preferably used for covering the slot position of the cathode lug, at least one part of cathode active substance can be properly extended and covered, the length of the covered cathode active substance can be more than 1mm, and the shape of the protective glue can be determined according to the shape of the slot position of the cathode lug; meanwhile, two second high-temperature protection glues 32 are arranged in an active material coating area of the cathode sheet, the positions of the second high-temperature protection glues 32 correspond to the first high-temperature protection glue 31 of the anode sheet after being wound, and the second high-temperature protection glue 32 of the cathode sheet completely covers the first high-temperature protection glue 31 on the anode sheet; finishing the preparation of the cathode plate;

(5) and winding the prepared anode sheet, cathode sheet and diaphragm 4 to prepare a battery core, adjusting the positions of the first high-temperature protection adhesive 31 and the second high-temperature protection adhesive 32 to be proper, then packaging the battery core into a shell, injecting liquid, forming and completing the preparation of the secondary battery.

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, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A secondary battery, characterized by comprising:

the first pole piece (1) is provided with a first pole lug (11);

a second pole piece (2) with opposite polarity to the first pole piece (1); a second tab (21) is arranged;

high-temperature protective glue (3), wherein the heat-resistant temperature is more than or equal to 300 ℃;

wherein the first tab (11) is arranged in an active substance coating area of the first pole piece (1); the surface of the first pole lug (11) is covered with the high-temperature protection glue (3), and/or the position of the second pole piece (2) opposite to the first pole lug (11) is covered with the high-temperature protection glue (3).

2. The secondary battery according to claim 1, wherein the surface of the first pole piece (1) not provided with the first tab (11) is the surface A of the first pole piece (1), and the surface A of the first pole piece (1) is also covered with the high-temperature protective adhesive (3) at a position opposite to the first tab (11).

3. The secondary battery according to claim 2, wherein the high-temperature protective adhesive (3) is disposed on the second pole piece (2) corresponding to the surface A of the first pole piece (1) at the position of the first tab (11).

4. The secondary battery according to claim 1, wherein the high temperature protection paste (3) comprises a first high temperature protection paste (31) and a second high temperature protection paste (32), the first high temperature protection paste (31) covers the surface of the first tab (11), and the second high temperature protection paste (32) covers the second tab (2) at a position opposite to the first tab (11).

5. The secondary battery according to claim 4, wherein the first high-temperature protective paste (31) is further covered with at least a portion of the active material coating region.

6. The secondary battery according to claim 5, wherein the width of the second high temperature protection paste (32) is greater than the width of the first high temperature protection paste (31); the length of the second high-temperature protection glue (32) is larger than that of the first high-temperature protection glue (31).

7. The secondary battery according to claim 6, wherein the width of the second high temperature protection paste (32) is at least 6mm greater than the width of the first high temperature protection paste (31); the length of the second high-temperature protection glue (32) is at least 3mm greater than that of the first high-temperature protection glue (31).

8. The secondary battery according to any one of claims 1 to 7, wherein the second tab (21) is provided in an active material coated region of the second pole piece (2); the surface of the second pole lug (21) is covered with the high-temperature protection glue (3), and/or the position of the first pole piece (1) opposite to the second pole lug (21) is covered with the high-temperature protection glue (3).

9. The secondary battery according to claim 1, wherein the first pole piece (1) is an anode piece, the second pole piece (2) is a cathode piece, the first tab (11) is an anode tab, and the second tab (21) is a cathode tab; the anode tab is arranged in an active material coating area of the anode sheet, and the two surfaces of the anode sheet at the corresponding position of the anode tab are covered with the high-temperature protection glue (3).

10. The secondary battery according to claim 9, further comprising a protective paste having a heat resistant temperature of < 300 ℃; the cathode lug is arranged in an active substance coating area of the cathode sheet or a head empty foil area of the cathode sheet, and the surface of the cathode lug is covered with the high-temperature protection glue (3) or the protection glue.