CN214588911U

CN214588911U - Battery with a battery cell

Info

Publication number: CN214588911U
Application number: CN202120818993.9U
Authority: CN
Inventors: 张保海; 彭冲; 李俊义
Original assignee: Zhuhai Cosmx Battery Co Ltd
Current assignee: Zhuhai Cosmx Battery Co Ltd
Priority date: 2021-04-20
Filing date: 2021-04-20
Publication date: 2021-11-02
Anticipated expiration: 2031-04-20

Abstract

The utility model provides a battery, which comprises a winding core, wherein the winding core comprises a first wound pole piece, a diaphragm and a second wound pole piece, the diaphragm is positioned between the adjacent first pole piece and the second pole piece, the first pole piece is provided with a first pole lug, and the second pole piece is provided with a second pole lug; the first tab is close to the first bent part at the first end of the winding core, the second tab is close to the second bent part at the second end of the winding core, the winding tail end of the winding core covers the first bent part, and the winding tail end of the winding core extends from the first bent part to the second bent part; the area between the second end tip of the winding core and the second pole lug is opposite to the first part of the winding core, and the first outer-layer gummed paper covers at least one side outer surface of the first part. Because first outer adhesive tape has certain thickness, can make the partial thickness grow that the first outer adhesive tape was covered in the subsides of core. Therefore, the battery provided by the embodiment solves the technical problem of poor surface flatness of the winding core structure in the lithium ion battery.

Description

Battery with a battery cell

Technical Field

The embodiment of the utility model provides a relate to battery technical field, especially relate to a battery.

Background

The lithium ion battery has the advantages of large capacity, small energy density, small volume, light weight, environmental protection and the like, and is widely applied to industries such as digital electronic products, electric automobiles and the like.

At present, a winding core of a lithium ion battery is generally formed by winding a positive plate, a negative plate and a diaphragm, and two tabs are respectively arranged on the positive plate and the negative plate.

However, the surface flatness of the winding core structure in the conventional lithium ion battery is poor, which can cause the problems of expansion and the like of the lithium ion battery in the cycle process, and shorten the cycle life of the lithium ion battery.

SUMMERY OF THE UTILITY MODEL

In view of this, the embodiment of the utility model provides a battery to it is great to solve the current both ends thickness difference of rolling up on the core width direction, can lead to lithium ion battery to take place the inflation in the cycle process, shortens lithium ion battery's cycle life's technical problem.

An embodiment of the utility model provides a battery, include: the winding core comprises a first pole piece, a diaphragm and a second pole piece which are wound, the diaphragm is positioned between the first pole piece and the second pole piece which are adjacent, the first pole piece is provided with a first pole lug, and the second pole piece is provided with a second pole lug;

the first tab is close to the first bent part at the first end of the winding core, the second tab is close to the second bent part at the second end of the winding core, the winding tail end of the winding core covers the first bent part, and the winding tail end of the winding core extends from the first bent part to the second bent part;

the outer side of the winding core comprises a first outer-layer gummed paper, the area between the second end tip and the second pole lug of the winding core is over against the first part of the winding core, and the first outer-layer gummed paper covers at least one side face of the first part.

So set up, set up the adhesive tape through the side in the outside at the second end of rolling up the core, because the adhesive tape has certain thickness, can increase the thickness of rolling up the core second end. Therefore, the flatness of the winding core is partially improved, the interface adhesion of the battery is good, the problems of expansion and deformation of the battery caused by unevenness are solved, and the long cycle life of the battery is prolonged.

In some embodiments that can include the above-mentioned embodiments, the first outer adhesive tape has a recess on a side facing away from the winding core, and the recess is opposite to the second bending portion.

In some embodiments, which may include the above-described embodiments, the thickness of the depression gradually increases from a middle region of the depression toward both sides;

and/or the thickness range of the middle area of the depressed part is more than or equal to 3 μm and less than or equal to 8 μm.

In some embodiments, which may include the above embodiments, the area between the bottom edges of the first and second tabs and the bottom surface of the jellyroll is opposite to the second portion of the jellyroll, one end of the second portion is aligned with the end of the first tab away from the second tab, and the other end of the second portion is aligned with the end of the second tab away from the first tab;

the outer side of the winding core further comprises a second outer-layer gummed paper, and the second outer-layer gummed paper covers at least one side face of the second portion.

In some embodiments that may include the above embodiments, the second outer-layer gummed paper covers both side surfaces and the bottom surface of the second portion, and the total length of the second outer-layer gummed paper is less than twice the distance between the bottom edges of the first tab and the second tab and the bottom surface of the winding core, and the thickness of the winding core is less than the difference, which is greater than or equal to-10 mm and less than or equal to 10 mm;

and/or subtracting the thickness of the first tab or the second tab from twice the thickness of the second outer-layer gummed paper to obtain a difference value of more than or equal to-5 μm and less than or equal to 5 μm.

In some embodiments, which may include the above embodiments, the projection of the first tab and the second tab on the side of the jellyroll has a gap, and the area between the first tab and the second tab faces the third portion of the jellyroll;

the outer side of the winding core further comprises a third outer-layer gummed paper, and the third outer-layer gummed paper covers at least one side face of the third portion.

In some embodiments, which may include the above embodiments, a third outer layer of adhesive tape covers both side surfaces and the top surface of the third portion, and the total length of the third outer layer of adhesive tape minus twice the length of the first tab or the second tab welding section minus the thickness of the winding core is greater than or equal to-10 mm and less than or equal to 10 mm;

and/or subtracting the thickness of the first tab or the second tab from twice the thickness of the third outer layer gummed paper to obtain a difference value of more than or equal to-5 μm and less than or equal to 5 μm.

In some embodiments that can include the above-mentioned embodiments, the first pole piece is the positive plate, the first utmost point ear is the positive pole ear, the positive plate includes positive current collector and positive active layer, the positive active layer coating is on the opposite two sides of positive current collector, the winding head end two sides of positive plate are exposed and are formed the empty foil district of positive pole, the positive pole ear sets up in the empty foil district of positive pole, the positive pole ear surface covers first positive pole ear adhesive tape, the one side that the positive plate deviates from the positive pole ear covers the second positive pole ear adhesive tape, first positive pole ear adhesive tape and the relative setting of second positive pole ear adhesive tape.

In some embodiments which can include the above embodiments, the inner side of the winding core includes first inner-layer adhesive paper, the two opposite surfaces of the positive electrode empty foil area are both provided with the first inner-layer adhesive paper, and one end of each of the two first inner-layer adhesive papers covers the head end of the positive electrode active layer;

the other ends of the two first inner-layer gummed papers are connected with the first positive tab gummed paper and one end of the second positive tab gummed paper far away from the second tab;

or the first positive tab gummed paper and the first inner layer gummed paper which are positioned on one side of the positive plate are integrally formed, and the second positive tab gummed paper and the first inner layer gummed paper which are positioned on the other side of the positive plate are integrally formed.

In some embodiments that can include above-mentioned embodiment, first pole piece is the positive plate, and first utmost point ear is the positive plate ear, and the positive plate includes positive current collector and positive active layer, and the inboard of book core still includes second inlayer adhesive tape, and the one end cover of second inlayer adhesive tape is at the terminal of two sides positive active layer, and the distance is more than or equal to 0mm and less than or equal to 3mm between the projection of the other end of second inlayer adhesive tape and the one end that the positive plate ear deviates from the second utmost point ear at the book core side.

In some embodiments, which may include the above embodiments, the terminal end of the positive electrode sheet further includes a terminal empty foil area with two exposed sides, the terminal empty foil area and the terminal end of the separator form a winding terminal end of the winding core, and the terminal end of the winding core is connected with the edge of the first outer adhesive paper or has a gap;

the thickness of the first outer-layer gummed paper is subtracted from the sum of the thicknesses of the positive tab, the first positive tab gummed paper, the second positive tab gummed paper, the double positive current collector and the double diaphragm to obtain a difference value which is larger than or equal to-5 mu m and smaller than or equal to 5 mu m.

In some embodiments, which may include the above embodiments, an end of the winding head end of the positive empty foil region extends between the positive tab and the second tab, and opposite sides of the winding head end of the positive empty foil region are each provided with a protective adhesive paper, and the two protective adhesive papers are located in an area between the positive tab and the second tab.

The battery provided by the embodiment comprises a winding core, wherein the winding core comprises a first wound pole piece, a diaphragm and a second wound pole piece, the diaphragm is positioned between the first pole piece and the second pole piece which are adjacent, the first pole piece is provided with a first pole lug, and the second pole piece is provided with a second pole lug; the first tab is close to the first bent part at the first end of the winding core, the second tab is close to the second bent part at the second end of the winding core, the winding tail end of the winding core covers the first bent part, and the winding tail end of the winding core extends from the first bent part to the second bent part; the outer side of the winding core comprises a first outer-layer gummed paper, the area between the second end tip and the second pole lug of the winding core is over against the first part of the winding core, and the first outer-layer gummed paper covers at least one side face of the first part. Because first outer adhesive tape has certain thickness, can increase the thickness that the core second end pasted and cover the adhesive tape department, be favorable to improving the roughness of rolling up the core, improve the interfacial bonding effect of the core of rolling up after the formation, finally realize improving the purpose of the long cycle life of battery, inflation problem and the deformation problem. Therefore, the battery provided by the embodiment solves the technical problems that the lithium ion battery expands and the like in the circulation process due to the fact that the thickness difference of the two ends of the winding core structure in the lithium ion battery in the width direction is large, and the circulation life of the lithium ion battery is shortened.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is easy to see that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a top view of a winding core in a battery provided by an embodiment of the present invention;

fig. 2 is a front view of a gummed paper attached to the outer side of a winding core in a battery provided by the embodiment of the utility model;

fig. 3 is a front view of an outer side surface of a winding core in a battery according to an embodiment of the present invention;

fig. 4 is a structural diagram of a first outer adhesive tape provided in an embodiment of the present invention;

FIG. 5 is a cross-sectional view taken along line A-A of FIG. 2;

FIG. 6 is an enlarged view of the central region of the winding core of FIG. 1;

fig. 7 is a front view of a positive plate in a battery provided by an embodiment of the present invention;

fig. 8 is a top view of a positive plate in a battery provided by an embodiment of the present invention;

fig. 9 is a top view of a battery thickness data collection location provided by an embodiment of the present invention;

fig. 10 is a side view of a battery thickness data collection location according to an embodiment of the present invention.

Description of reference numerals:

1: a winding core;

10: a first pole piece;

20: a second pole piece;

30: a first tab;

40: a second tab;

110: a positive current collector;

120: a positive electrode active layer;

130: a positive electrode empty foil region;

140: a terminal empty foil region;

150: protecting the gummed paper;

210: a negative current collector;

220: a negative electrode active layer;

230: a negative empty foil region;

320: a first positive tab gummed paper;

330: a second positive tab gummed paper;

420: negative tab gummed paper;

510: a third outer layer of gummed paper;

520: a second outer adhesive paper layer;

530: a first outer layer of gummed paper;

531: a recessed portion;

610: a first inner layer gummed paper;

620: a second inner layer gummed paper;

710: a third portion;

720: a second portion;

730: a first portion.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

A lithium ion battery is a secondary battery (rechargeable battery) which mainly depends on the movement of lithium ions between a positive electrode and a negative electrode, and the energy density, the quick charging capability, the charge-discharge rate and the like of the lithium ion battery affect the service performance of the lithium ion battery.

In the related technology, the key to whether the interface bonding of the lithium ion battery is good is whether the pressure borne by the lithium ion battery in the formation process is uniform, and the key to whether the pressure borne by the lithium ion battery in the formation process is uniform is whether the flatness of the whole winding core in the design process of the winding core is good; if the flatness of the roll core is poor, the pressure born by the pole piece is uneven in the formation process, and finally the problems of uneven surface, sinking, wave deformation and the like of the roll core occur. The problem of flatness of the roll core can cause uneven stress on the roll core in the cyclic expansion process in the long cycle process, and finally, the roll core is expanded and deformed to cause capacity attenuation and expansion failure. The winding core may include a first end and a second end in a width direction, and a distal end of the winding core may cover the first end of the winding core and extend from the first end in a direction toward the second end.

However, the thickness of different parts of the battery is different due to factors such as the position of the tail end of the winding core, the structure of the positive/negative electrode sheet, the structure of the positive/negative electrode tab, the welding position of the positive/negative electrode tab, the arrangement mode of the diaphragm and the like, especially, the thickness of the second end of the winding core is smaller, the flatness of the winding core of the battery is poorer, the interface bonding effect of the battery after formation is further influenced, the expansion problem and the deformation problem of the battery are aggravated, and the long cycle life of the battery is shortened.

In order to solve the above technical problem, this embodiment provides a battery, and the side in the outside through the second end at rolling up the core sets up the adhesive tape, because the adhesive tape has certain thickness, can increase the thickness of rolling up core second end. Therefore, the flatness of the winding core is partially improved, the interface adhesion of the battery is good, the problems of expansion and deformation of the battery caused by unevenness are solved, and the long cycle life of the battery is prolonged.

As shown in fig. 1, the present embodiment provides a battery, which includes a winding core 1, the winding core 1 includes a first pole piece 10, a diaphragm (not shown) and a second pole piece 20, the diaphragm is located between the first pole piece 10 and the second pole piece 20, the first pole piece 10 is provided with a first pole tab 30, and the second pole piece 20 is provided with a second pole tab 40.

Specifically, the first tab 10 may be a positive tab, the first tab 30 may be a positive tab, the second tab 20 may be a negative tab, and the second tab 40 may be a negative tab.

Alternatively, the first tab 10 may be a negative tab, the first tab 30 may be a negative tab, the second tab 20 may be a positive tab, and the second tab 40 may be a positive tab, which is not limited herein.

Wherein, first utmost point ear 30 is close to the first kink of rolling up core 1, and first kink is located the first end of rolling up core 1, and second utmost point ear 40 is close to the second kink of rolling up core 1, and the second kink is located the second end of rolling up core 1.

The winding tail end of the winding core 1 covers the first bending part, and the winding tail end of the winding core 1 extends from the first bending part to the second bending part. The first end of the core 1 is covered by the end of the core 1 and the second end of the core 1 is uncovered by the end of the core 1. The thickness of different parts of the battery is different due to factors such as the tail end position of the battery winding core 1, the structures of the two pole pieces, the two pole lugs, the welding positions of the two pole lugs, the arrangement mode of the diaphragm and the like, and particularly the thickness of the second end of the battery winding core 1 is smaller, so that the flatness of the battery winding core 1 is poor.

With continued reference to fig. 2 and 3, the area between the second end of the winding core 1 and the second tab 40 is opposite to the first portion 730 of the winding core 1, and in order to make the transition between the first end and the second end of the winding core 1 smooth, a first outer layer adhesive tape 530 may be disposed on the outer side of the winding core 1, and the first outer layer adhesive tape 530 covers at least one side surface of the first portion 730.

The side surfaces of the core 1 are both surfaces in the thickness direction of the core 1.

Specifically, the first outer adhesive tape 530 may be attached to any one side of the outer surface of the winding core 1, or the first outer adhesive tape 530 may be attached to opposite sides of the outer surface of the winding core 1. For example, the first outer adhesive tape 530 may be wound around the outer surface of the other side of the winding core 1 from the outer surface of one side of the winding core 1 through the second bending portion, or may be attached to two opposite surfaces of the winding core 1. Because the first outer adhesive tape 530 has a certain thickness, the thickness of the place where the first outer adhesive tape 530 is attached to the winding core 1 can be increased. The flatness of the winding core 1 is improved, the interface bonding effect of the formed winding core 1 is improved, and the purposes of prolonging the cycle life, solving the expansion problem and solving the deformation problem of the battery are finally achieved.

On the other hand, the first tab 30 and the second tab 40 are arranged on the inner side of the winding core 1, and because the first tab 30 and the second tab 40 have a certain thickness, the side surface of the winding core 1 opposite to the first tab 30 and the second tab 40 protrudes to the outer side of the winding core 1, so that the thickness is larger, and the thickness of the rest part of the winding core 1 is smaller, so that the thickness of the winding core is uneven. At this moment, when setting up first outer adhesive tape 530, can take into account the thickness of utmost point ear, be favorable to improving the roughness of rolling up core 1.

The battery provided by the embodiment comprises a winding core 1, wherein the winding core 1 comprises a first pole piece 10, a diaphragm and a second pole piece 20 which are wound, the diaphragm is positioned between the first pole piece 10 and the second pole piece 20 which are adjacent, the first pole piece 10 is provided with a first pole lug 30, and the second pole piece 20 is provided with a second pole lug 40; the first tab 30 is close to a first bent part at the first end of the winding core 1, the second tab 40 is close to a second bent part at the second end of the winding core 1, the winding tail end of the winding core 1 covers the first bent part, and the winding tail end of the winding core 1 extends from the first bent part to the second bent part; the outside of the core 1 includes a first outer layer adhesive tape 530, the area between the second end of the core 1 and the second tab 40 is opposite to the first portion 730 of the core 1, and the first outer layer adhesive tape 530 covers at least one side of the first portion 730. Because the first outer adhesive tape has a certain thickness, the thickness of the first outer adhesive tape 530 attached to the winding core 1 can be increased. The flatness of the winding core 1 is improved, the interface bonding effect of the formed winding core 1 is improved, and the purposes of prolonging the cycle life, solving the expansion problem and solving the deformation problem of the battery are finally achieved.

Therefore, the battery provided by the embodiment solves the technical problems that the surface flatness of the winding core 1 structure in the lithium ion battery is poor, the lithium ion battery expands in the circulation process and the like, and the circulation life of the lithium ion battery is shortened.

Further, as shown in fig. 1 and fig. 4, a surface of the first outer layer adhesive tape 530 facing away from the winding core 1 has a concave portion 531, the concave portion 531 faces the outer side of the winding core 1, and the concave portion 531 is opposite to the curved outer side surface of the winding core 1, that is, the concave portion 531 is opposite to the second bending portion. Since the middle area of the depressed part 531 has a smaller thickness than the areas at both ends, the depressed part 531 faces the second bent part of the core 1. So set up, can increase the corresponding thickness that 1 pastes the gummed paper department of rolling up core, and do not increase the width of rolling up core 1 as far as possible. The width direction of the pole piece is the length direction of the winding core 1, and the length direction of the pole piece is the width direction of the winding core 1.

In order to make the transition of the first outer layer of gummed paper 530 from the middle to both ends smooth, the thickness of the depressed portion 531 gradually increases from the middle area of the depressed portion 531 to both sides. Illustratively, the cross-sectional profile of the recess 531 may be angular or arcuate.

The thickness of the middle region of the depressed portion 531 is 3 μm or more and 8 μm or less. Illustratively, the thickness of the middle region of the concave portion 531 may be set to 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm or any value between 3 μm and 8 μm according to actual needs, which is not limited herein.

With continued reference to fig. 3 and fig. 5, in the present embodiment, the area between the bottom edges of the first tab 30 and the second tab 40 and the bottom surface of the winding core 1 is opposite to the second portion 720 of the winding core 1, one end of the second portion 720 is aligned with the end of the first tab 30 away from the second tab 40, and the other end of the second portion 720 is aligned with the end of the second tab 40 away from the first tab 30. The bottom edges of the first tab 30 and the second tab 40 are both close to the bottom surface of the winding core 1.

Further, the outer side of the winding core 1 further comprises a second outer adhesive paper 520, and the second outer adhesive paper 520 covers at least one side surface of the second portion 720. Specifically, the second outer adhesive paper 520 may be attached to any one side of the outer surface of the core 1, or the second outer adhesive paper 520 may be attached to opposite sides of the outer surface of the core 1.

The second outer adhesive paper 520 can be wound around the outer surface of the other side of the winding core 1 from the outer surface of one side of the winding core 1 through the bottom surface of the winding core 1, and can also be only attached to the two opposite surfaces of the winding core 1. Because the second outer adhesive paper 520 has a certain thickness, the thickness of the second portion 720 can be improved, and the flatness of the winding core 1 can be improved.

Optionally, the second outer-layer gummed paper 520 can be covered on the two side surfaces and the bottom surface of the second portion 720, so that the thickness of the winding core 1 in the area covered by the second outer-layer gummed paper 520 can be increased, and the winding core 1 can be partially wrapped, so that the anti-falling performance of the battery is improved.

Optionally, the total length of the second outer-layer adhesive paper 520 is subtracted by twice the distance between the bottom edge of the first tab 30 and the second tab 40 and the bottom surface of the winding core 1, and then the thickness of the winding core 1 is subtracted, so that the obtained difference is greater than or equal to-10 mm and less than or equal to 10 mm.

The length of the adhesive paper is along the length direction of the winding core, and the width of the adhesive paper is along the width direction of the winding core.

Optionally, the difference obtained by subtracting the thickness of the first tab 30 or the second tab 40 from twice the thickness of the second outer-layer gummed paper 520 is greater than or equal to-5 μm and less than or equal to 5 μm.

Optionally, the width of the second outer adhesive paper 520 is smaller than or equal to the width of the second portion 720, so as to ensure that the second outer adhesive paper 520 is located in the area of the second portion 720, thereby being beneficial to improving the flatness of the winding core 1.

In this embodiment, the projections of the first tab 30 and the second tab 40 on the side of the winding core 1 have a gap, that is, the first tab 30 and the second tab 40 are staggered in the width direction of the winding core 1, so as to avoid the unevenness of the winding core 1 caused by the thickness superposition of the first tab 30 and the second tab 40. The area between the first tab 30 and the second tab 40 faces the third portion 710 of the reeling core 1.

Further, the outer side of the winding core 1 further includes a third outer layer adhesive paper 510, and the third outer layer adhesive paper 510 covers at least one side surface of the third portion 710.

Specifically, the third outer adhesive tape 510 may be attached to any side of the outer surface of the winding core 1, or the third outer adhesive tape 510 may be attached to opposite sides of the outer surface of the winding core 1.

The third outer adhesive paper 510 can be wound around the other side outer surface of the winding core 1 from the outer surface of one side of the winding core 1 through the top surface of the winding core 1, and can be only attached to the two opposite surfaces of the winding core 1. Since the third outer layer adhesive paper 510 has a certain thickness, it is beneficial to improve the thickness of the third portion 710, thereby improving the flatness of the winding core 1.

Optionally, the third outer-layer adhesive paper 510 may cover both sides and the top surface of the third portion 710, so that the thickness of the winding core 1 in the area covered by the third outer-layer adhesive paper 510 may be increased, and the winding core 1 may be partially wrapped to improve the anti-drop performance of the battery.

Optionally, the difference obtained by subtracting twice the length of the welding section of the first tab 30 or the second tab 40 from the total length of the third outer layer adhesive paper 510 and then subtracting the thickness of the winding core 1 is greater than or equal to-10 mm and less than or equal to 10 mm.

Optionally, the difference obtained by subtracting the thickness of the first tab 30 or the second tab 40 from twice the thickness of the third outer layer adhesive tape 510 is greater than or equal to-5 μm and less than or equal to 5 μm.

Optionally, the width of the third outer adhesive paper 510 is smaller than or equal to the width of the third portion 710, so as to ensure that the third outer adhesive paper 510 is located in the area of the third portion 710, thereby being beneficial to improving the flatness of the winding core 1.

With reference to fig. 1 and fig. 6, in this embodiment, the first pole piece 10 is a positive pole piece, the first tab 30 is a positive pole tab, the positive pole piece includes a positive pole current collector 110 and a positive pole active layer 120, and the positive pole active layer 120 is coated on two opposite sides of the positive pole current collector 110. For example, the positive electrode current collector 110 may be an aluminum foil, and of course, the positive electrode current collector 110 may also be made of other materials according to actual needs, as long as the requirements of the winding core 1 can be met.

The two surfaces of the winding head end of the positive plate are exposed to form a positive empty foil area 130, and the positive tab is arranged in the positive empty foil area 130. In order to avoid the situation that burrs generated by welding the positive electrode tab on the positive electrode current collector 110 pierce through the middle diaphragm of the two electrode plates to cause short circuit of the battery, the first positive electrode tab gummed paper 320 can be covered on the surface of the positive electrode tab, the second positive electrode tab gummed paper 330 can be covered on the surface of the positive electrode tab, which deviates from the positive electrode tab, and the first positive electrode tab gummed paper 320 and the second positive electrode tab gummed paper 330 are arranged oppositely.

Wherein, the size range of the positive tab in the width direction of the positive plate can be 25mm to 55 mm; the size range of the positive tab in the length direction of the positive plate can be 5mm to 10 mm; the thickness of the positive tab may range from 45 μm to 110 μm; the size range of the first positive tab gummed paper 320 and the second positive tab gummed paper 330 in the length direction of the positive plate can be 10mm to 20 mm; the thickness of the first and second

positive tab sheets

320 and 330 may range from 5 μm to 16 μm.

Referring to fig. 6-8, in this embodiment, the inner side of the winding core 1 may further include first inner adhesive tapes 610, the first inner adhesive tapes 610 are disposed on two opposite sides of the positive electrode empty foil area 130, and one end of each of the two first inner adhesive tapes 610 covers the head end of the positive electrode active layer 120, so as to prevent burrs at the coated head end of the positive electrode active layer 120 from piercing through the separator between the two electrode sheets, which may cause a short circuit of the battery.

In the length direction of the positive plate, the range of the first inner layer adhesive paper 610 covering the head end of the positive active layer 120 is 1mm-3 mm.

Optionally, the other ends of the two first inner layers of adhesive tapes 610 are connected with the ends, away from the second tab 40, of the first tab adhesive tape 320 and the second tab adhesive tape 330, so that the thickness of the end, away from the second tab 40, of the winding core 1, which is located on the positive tab is kept uniform, and the surface unevenness of the winding core 1 is improved.

Optionally, the first positive tab adhesive tape 320 and the first inner layer adhesive tape 610 on one side of the positive tab are integrally formed, that is, the first inner layer adhesive tape 610 and the first positive tab adhesive tape 320 on the side of the positive tab where the first positive tab adhesive tape 320 is disposed may be an integral piece.

Optionally, the second tab adhesive paper 330 on the other side of the positive tab and the first inner adhesive paper 610 are integrally formed, that is, the first inner adhesive paper 610 and the second tab adhesive paper 330 on the side of the positive tab facing away from the positive tab may be an integral piece.

With continued reference to fig. 1 and fig. 6, in this embodiment, the second tab 20 may be a negative tab, the second tab 40 may be a negative tab, the negative tab includes a negative current collector 210 and a negative active layer 220, the negative active layer 220 is coated on two opposite surfaces of the negative current collector 210, two sides of a winding head end of the negative tab are exposed to form a negative empty foil area 230, the negative tab is disposed in the negative empty foil area 230, and a surface of the negative tab covers the negative tab adhesive paper 420.

For example, the negative electrode current collector 210 may be made of copper foil, and of course, the negative electrode current collector 210 may be made of other materials according to actual needs as long as the requirement of the winding core 1 can be met.

The size range of the negative electrode tab in the width direction of the negative electrode sheet can be 25mm to 55 mm; the size range of the negative electrode tab in the length direction of the negative electrode sheet can be 5mm to 10 mm; the thickness of the negative electrode tab may range from 45 μm to 110 μm; the size range of the negative tab adhesive paper 420 in the length direction of the negative plate may be 10mm to 20 mm; the thickness of the negative tab paper 420 may range from 5 μm to 16 μm.

In this embodiment, the end of the winding head end of the positive empty foil area 130 extends to between the first tab 30 and the second tab 40, the two opposite surfaces of the winding head end of the positive empty foil area 130 are provided with the protection adhesive papers 150, and the two protection adhesive papers 150 are located in the area between the first tab 30 and the second tab 40.

Alternatively, one end of each of the two pieces of protection adhesive paper 150 may be connected to one end of the first positive tab adhesive paper 320 and the second positive tab adhesive paper 330, which are close to the negative tab, and the other end of each of the two pieces of protection adhesive paper 150 may be connected to one end of the negative tab adhesive paper 420, which is close to the positive tab.

The protective adhesive tape 150 may be attached to the negative electrode current collector 210 on the opposite surfaces of the positive electrode current collector 110, may be directly attached to the positive electrode current collector 110, or may be attached to the separators on the opposite surfaces of the positive electrode current collector 110. The protective adhesive tape 150 can prevent the burrs on the cutting part of the positive current collector 110 from piercing the diaphragm to cause the internal short circuit of the winding core 1, and can also increase the thickness of the winding core 1 between the first tab 30 and the second tab 40, so as to improve the unevenness of the surface of the winding core 1.

In some embodiments, the first inner adhesive tape 610, the first positive tab adhesive tape 320, and the protective adhesive tape 150 on the same side of the positive electrode current collector 110 may be integrally formed complete adhesive tapes; or, two adjacent gummed papers are integrally formed, and the other gummed paper is independent; or the three gummed papers are all independent gummed papers. The principles of the first inner adhesive tape 610, the second positive tab adhesive tape 330 and the protective adhesive tape 150 on the same side of the positive current collector 110 are similar, and are not described herein again.

In this embodiment, the inner side of the winding core 1 further includes a second inner layer adhesive paper 620, and one end of the second inner layer adhesive paper 620 covers the ends of the two positive electrode active layers 120, so as to prevent burrs at the coating end of the positive electrode active layer 120 from piercing through the separator between the two electrode plates, thereby causing a short circuit of the battery. The distance between the projection of the other end of the second inner layer adhesive paper 620 on the side surface of the winding core 1 and the projection of one end of the positive lug departing from the second lug 40 on the side surface of the winding core 1 is greater than or equal to 0mm and less than or equal to 3 mm. So that the thickness of the winding core 1 at the end of the positive tab far away from the second tab 40 is kept uniform, thereby being beneficial to improving the uneven condition of the surface of the winding core 1.

Wherein, in the length direction of the positive plate, the range of the second inner gummed paper 620 covering the tail end of the positive active layer 120 is 1mm-3 mm.

In order to avoid the head end and the tail end of the positive electrode active layer 120 to set up the position and cause the uneven surface thickness of the winding core 1, the head end and the tail end of the positive electrode active layer 120 on the two sides of the positive electrode plate can be set up at the bending part of the winding core 1, for example: a first bending part. The first bending portion includes a beginning end and an ending end of the bending portion, that is, two ends of the positive active layer 120 may be located at any position between the beginning end, the ending end and the two ends of the bending portion, and one end of the corresponding two inner layer adhesive tapes is also located at any position between the beginning end, the ending end and the two ends of the bending portion.

As shown in fig. 1, the adhesive tape of the first inner adhesive tape 610 covering the head end of the positive electrode active layer 120 is aligned with the end of the first bent portion, and the adhesive tape of the second inner adhesive tape 620 covering the tail end of the positive electrode active layer 120 is aligned with the start end of the first bent portion. Because roll up the smooth transition structure of core 1 both ends kink for the bending, the thickness of kink is less than the non-kink thickness of rolling up the core, consequently lies in the structure of kink and hardly influences the roughness of rolling up core 1. So the thickness of the gummed paper at the bending part can be ignored. At this time, the sum of the thicknesses of the first inner adhesive sheets 610 and the second inner adhesive sheets 620 on both sides minus the sum of the thicknesses of the positive electrode tab, the first positive electrode tab adhesive sheet 320, and the second positive electrode tab adhesive sheet 330 is greater than or equal to-5 μm and less than or equal to 5 μm.

In this embodiment, the thicknesses of the first inner adhesive tapes 610 disposed on the opposite sides of the positive electrode current collector 110 may be the same or different; the widths of the first inner adhesive paper 610 on both sides may be the same or different. The second inner adhesive tape 620, the protective adhesive tape 150, and the like are similar to each other, and are not described herein again.

In this embodiment, the end of the positive electrode sheet further includes a double-sided exposed end empty foil region 140, the end empty foil region 140 and the end of the separator (not shown) form the winding end of the winding core 1, and the end of the winding core 1 is connected with the edge of the first outer adhesive tape 530 or has a gap.

Alternatively, when the end of the winding core 1 is located between the first tab 30 and the second tab 40, that is, the end of the winding core 1 is located between the projections of the first tab 30 and the second tab 40 on the side of the winding core 1. Because the third outer adhesive tape 510 is attached to the end of the winding core 1, the end of the winding core 1 can be prevented from being separated from the winding core 1 due to warping.

Optionally, the end of the winding core 1 is close to the edge of the first outer layer adhesive tape 530, except that the third outer layer adhesive tape 510 can prevent the end of the winding core 1 from warping, the end adhesive tape can be separately attached to the end of the winding core 1 to prevent the end of the winding core 1 from warping and separating from the winding core 1. And because the tail end of the winding core 1 is close to the edge of the first outer layer adhesive paper 530, the gap between the tail end of the winding core and the first outer layer adhesive paper is small, so that the unevenness caused by the depression at the gap between the tail end of the winding core and the first outer layer adhesive paper is avoided.

Optionally, similarly, the end of the winding core 1 is connected to the edge of the first outer layer adhesive tape 530, or the end adhesive tape may be separately attached to the end of the winding core 1, so as to prevent the end of the winding core 1 from being warped and separated from the winding core 1. Wherein the tail end gummed paper is arranged as thin as possible to avoid the influence of the tail end gummed paper on the thickness of the winding core 1.

At this time, the thickness of the double first outer layer adhesive tape 530 is subtracted from the sum of the thicknesses of the positive tab, the first positive tab adhesive tape 320, the second positive tab adhesive tape 330, the double positive current collector 110 and the double diaphragm, and the obtained difference is greater than or equal to-5 μm and less than or equal to 5 μm, so that the surface unevenness of the winding core 1 is favorably improved.

In this embodiment, the adhesive paper used, such as the first outer adhesive paper 530, the second outer adhesive paper 520, the third outer adhesive paper 510, the first inner adhesive paper 610, the second inner adhesive paper 620, each tab adhesive paper, the protective adhesive paper 150, can be divided into two layers, one of the layers of the adhesive paper is a substrate film layer, the other layer of the adhesive paper is an adhesive layer, and the substrate film layer can be made of: CPP, OPP, BOPP, PE, PET, PVC or MOPP etc. the material of glue layer can be: water glue, oil glue, hot melt glue, natural rubber or synthetic rubber, etc. The thickness of the glue layer is 1 μm to 5 μm, and may be 1 μm, 2 μm, 3 μm, 4 μm, and the like, which is not limited herein, and the thickness of the substrate may be selected according to the requirement.

In some embodiments, the difference between the thickness of the positive electrode tab minus the thickness of the negative electrode tab is greater than or equal to-5 μm and less than or equal to 5 μm.

Optionally, the difference obtained by subtracting the sum of the thicknesses of the first positive tab adhesive paper 320 and the second positive tab adhesive paper 330 from the thickness of the negative tab adhesive paper 420 is greater than or equal to-5 μm and less than or equal to 5 μm.

Optionally, the difference between the thicknesses of the positive tab and the negative tab is large, and at this time, the thickness of the first positive tab adhesive paper 320, the second positive tab adhesive paper 330, and the thickness of the negative tab adhesive paper 420 may be adjusted so that the sum of the thicknesses of the positive tab, the first positive tab adhesive paper 320, and the second positive tab adhesive paper 330 is subtracted by the sum of the thicknesses of the negative tab and the negative tab adhesive paper 420, and the obtained difference is greater than or equal to-5 μm and less than or equal to 5 μm. So that the thickness of the surface of the battery is more uniform.

By comparing the three battery examples provided by the embodiment with the comparative battery example provided by the non-embodiment, table 1 shows the settings of the parameters of the three examples and the comparative example, table 2 shows the thickness distribution of different parts of the three examples and the comparative example, and fig. 9 and 10 show the position diagram of the battery thickness data acquisition. The parameter settings and cycle test data are shown in tables 1 and 2 below:

TABLE 1

TABLE 2

	Example 1	Example two	Example three	Comparative example
					a thickness mm	4.362	4.365	4.364	4.353
b is mm in thickness	4.362	4.364	4.365	4.360
					Thickness mm at position c	4.361	4.362	4.363	4.300
d is mm thick	4.361	4.363	4.363	4.300
					e thickness mm	4.362	4.362	4.365	4.218
Thickness mm at f	4.364	4.363	4.364	4.345
					Thickness of g	4.362	4.363	4.363	4.309
Extremely poor (flatness)	0.003	0.003	0.002	0.142
					Retention of circulating capacity 800T/%)	83.27	82.92	83.01	75.35
Cell swell 800T/%)	9.28	9.03	9.35	11.03

Two adhesive tapes are arranged between the bottom edge of each tab and the bottom surface of the winding core 1 in the comparative example in table 1, one adhesive tape is arranged between the bottom edge of the tab and the bottom surface of the winding core 1, and the other adhesive tape is arranged between the bottom edge of the tab and the bottom surface of the winding core 1.

In this embodiment, the 3D high-resolution microscope used for testing the thickness is used, and the measurement may have a certain error due to the operation problem, but the error may be controlled within an error range of 0.01mm, and meanwhile, in the battery preparation process, there may also be an error in the design value and the actual measurement value due to the influence of factors such as the thickness difference of the coated pole piece, but the error may be basically controlled within a range of 0.03 mm.

The data in analysis table 1 and table 2 can be known, through set up adhesive tapes such as first outer adhesive tape 530, second outer adhesive tape 520 and third outer adhesive tape 510 at core 1 lateral surface, can effectively improve battery thickness distribution, pole piece atress is uneven when improving into leads to core 1 to appear the surface uneven, sunken and wave deformation scheduling problem, even formation pressure can also effectively improve the poor problem of diaphragm bonding, it is poor to improve the cohesiveness between circulation later stage pole piece and diaphragm, arouse the problem of lithium analysis, improve the roughness of core 1, change the condition that the circulation inflation became invalid simultaneously.

The battery that provides in this embodiment can effectively improve long circulation in-process and can lead to rolling up core 1 at cyclic expansion in-process pole piece internal stress inhomogeneous because of the roughness problem of rolling up core 1, finally leads to rolling up core 1 and bonding cross-section inefficacy, roll up core 1 dilatational strain, causes the problem of capacity decay, dilatational failure, promotes battery cycle life and security performance. The winding core 1 is wrapped inside by a battery shell, and the positive electrode lug and the negative electrode lug respectively form a positive electrode and a negative electrode of the battery. When the battery is applied to the electronic equipment, the positive electrode of the battery is connected and conducted with the positive electrode of the electronic equipment, and the negative electrode of the battery is connected and conducted with the negative electrode of the electronic equipment, so that the battery supplies power to the electronic equipment.

It should be noted that the numerical values and numerical ranges related to the embodiments of the present application are approximate values, and there may be a certain range of errors depending on the manufacturing process, and the error may be considered as negligible by those skilled in the art.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

Claims

1. A battery, comprising: the winding core comprises a first wound pole piece, a diaphragm and a second wound pole piece, the diaphragm is positioned between the first pole piece and the second pole piece which are adjacent, a first pole lug is arranged on the first pole piece, and a second pole lug is arranged on the second pole piece;

the first tab is close to a first bent part at the first end of the winding core, the second tab is close to a second bent part at the second end of the winding core, the winding tail end of the winding core covers the first bent part, and the winding tail end of the winding core extends from the first bent part to the second bent part;

the outer side of the winding core comprises a first outer-layer adhesive paper, the second end head of the winding core and the area between the second pole lugs are opposite to the first part of the winding core, and the first outer-layer adhesive paper covers at least one side face of the first part.

2. The battery of claim 1, wherein a side of the first outer adhesive paper facing away from the winding core has a recess, and the recess is opposite to the second bending portion.

3. The battery according to claim 2, wherein the thickness of the depression gradually increases from a middle region of the depression toward both sides;

4. The battery of any of claims 1-3, wherein an area between the bottom edges of the first and second tabs and the bottom surface of the jellyroll is aligned with a second portion of the jellyroll, one end of the second portion being aligned with an end of the first tab distal from the second tab, the other end of the second portion being aligned with an end of the second tab distal from the first tab;

the outer side of the winding core further comprises second outer-layer gummed paper, and the second outer-layer gummed paper covers at least one side face of the second portion.

5. The battery of claim 4, wherein the second outer adhesive tape covers both side surfaces and the bottom surface of the second portion, and the total length of the second outer adhesive tape is less than twice the distance between the bottom edges of the first and second tabs and the bottom surface of the winding core and less than the thickness of the winding core by a difference of-10 mm to 10 mm;

6. The battery of any of claims 1-3, wherein a projection of the first tab and the second tab on a side of the jellyroll has a gap, and an area between the first tab and the second tab faces a third portion of the jellyroll;

7. The battery of claim 6, wherein the third outer layer of adhesive tape covers both sides and the top of the third portion, and the total length of the third outer layer of adhesive tape minus twice the length of the first tab or the second tab welded section minus the thickness of the winding core is greater than or equal to-10 mm and less than or equal to 10 mm;

8. The battery according to any one of claims 1 to 3, wherein the first electrode sheet is a positive electrode sheet, the first tab is a positive electrode tab, the positive electrode sheet comprises a positive electrode current collector and a positive electrode active layer, the positive electrode active layer is coated on two opposite surfaces of the positive electrode current collector, two opposite surfaces of the winding head end of the positive electrode sheet are exposed to form a positive electrode empty foil area, the positive electrode tab is arranged in the positive electrode empty foil area, the surface of the positive electrode tab is covered with first positive electrode tab gummed paper, one surface of the positive electrode sheet, which is far away from the positive electrode tab, is covered with second positive electrode tab gummed paper, and the first positive electrode tab gummed paper and the second positive electrode tab gummed paper are arranged oppositely.

9. The battery according to claim 8, wherein the inner side of the winding core comprises first inner-layer gummed papers, the two opposite surfaces of the positive electrode empty foil area are provided with the first inner-layer gummed papers, and one ends of the two first inner-layer gummed papers respectively cover the head end of the positive electrode active layer;

the other ends of the two first inner-layer gummed papers are connected with one ends of the first positive tab gummed paper and the second positive tab gummed paper, which are far away from the second tab;

or the first positive tab gummed paper and the first inner layer gummed paper on one side of the positive plate are integrally formed, and the second positive tab gummed paper and the first inner layer gummed paper on the other side of the positive plate are integrally formed.

10. The battery according to any one of claims 1 to 3, wherein the first electrode sheet is a positive electrode sheet, the first electrode tab is a positive electrode tab, the positive electrode sheet comprises a positive electrode current collector and a positive electrode active layer, the inner side of the winding core further comprises a second inner adhesive tape, one end of the second inner adhesive tape covers both sides of the tail end of the positive electrode active layer, and the distance between the other end of the second inner adhesive tape and the projection of one end of the positive electrode tab departing from the second electrode tab on the side surface of the winding core is greater than or equal to 0mm and less than or equal to 3 mm.

11. The battery according to claim 8, wherein the terminal end of the positive plate further comprises a terminal empty foil area with two exposed sides, the terminal empty foil area and the terminal end of the separator form a winding terminal end of the winding core, and the terminal end of the winding core is connected with the edge of the first outer adhesive paper layer or has a gap;

and subtracting twice of the thickness of the first outer-layer gummed paper from the sum of the thicknesses of the positive lugs, the first positive lug gummed paper, the second positive lug gummed paper, twice of the positive current collector and twice of the diaphragm to obtain a difference value which is more than or equal to-5 mu m and less than or equal to 5 mu m.

12. The battery of claim 8, wherein an end portion of the winding head end of the positive electrode empty foil region extends between the positive electrode tab and the second electrode tab, and protective adhesive sheets are disposed on opposite sides of the winding head end of the positive electrode empty foil region, and the two protective adhesive sheets are located in an area between the positive electrode tab and the second electrode tab.