CN212587689U

CN212587689U - Pole piece for button cell and button cell

Info

Publication number: CN212587689U
Application number: CN202020748130.4U
Authority: CN
Inventors: 叶柏青; 陈俊
Original assignee: Ganzhou Norway Technology Co ltd
Current assignee: Ganzhou Norway Technology Co ltd
Priority date: 2020-05-07
Filing date: 2020-05-07
Publication date: 2021-02-23
Anticipated expiration: 2030-05-07

Abstract

The utility model provides a pole piece for a button cell and the button cell, wherein the pole piece comprises a current collector; the tab is provided with tab glue, one end part of the tab is provided with a welding area, and the tab is welded on the current collector through the welding area; at least one part of the tab glue is overlapped with the current collector, and a bendable flexible part is formed between the welding area and the tab glue. Compared with the prior art, the utility model discloses a button cell overlaps with at least partly and the mass flow body that utmost point ear glued, and sets up the weld zone of utmost point ear at the tip position, can form flexible portion in order to buckle from this between weld zone and the utmost point ear glue, and the setting of this flexible portion has been avoided can forming the closed angle because of utmost point ear is buckled from the top and cause the crowded broken risk hidden danger of plastic-aluminum membrane, and utmost point ear is directly buckled in flexible portion region simultaneously, has thoroughly solved the plastic-aluminum membrane and has punctured the problem that leads to the weeping to rise gas.

Description

Pole piece for button cell and button cell

Technical Field

The utility model relates to a button cell field, concretely relates to pole piece and button cell for button cell.

Background

Button cells generally include a lid, a case, and a cell, and the cell is placed in the case and fastened to form a closed space by the lid and the case. The existing button cell generally has two packaging methods, including hard shell packaging and soft package packaging. The hard shell is mainly packaged by means of physical blocking and hard shell adding, but the packaging effect is not stable, and if electrolyte is directly injected into the shell, the risk of electrolyte leakage exists. And adopt soft package encapsulation, as shown in fig. 1, the positive negative pole ear of the electric core that the coiling was accomplished is vertically located the head of electric core usually, can roll over the utmost point ear earlier and carry out primary bending to both sides when the plastic-aluminum membrane encapsulates, wherein primary bending is rolled over by the top of plastic-aluminum membrane usually, wait to accomplish again after the encapsulation with utmost point ear bend turn back with the vertical parallel position of electric core head, also so conventional utmost point ear glue can set up in the periphery of pole piece, reserve partly utmost point ear region between utmost point ear glue and pole piece and be used for primary bending, but this kind of encapsulated structure still has following problem:

firstly, the tab is usually a metal band with the thickness of 0.1-0.2 mm, a sharp corner is formed at the bending position, the aluminum-plastic film can be easily broken when the tab is bent for the first time, the risk of liquid leakage and air expansion is generated, and meanwhile, the tab is not attractive in appearance.

Secondly, the tab is packaged in the aluminum-plastic film for the first time, and then is bent back from the packaging edge of the aluminum-plastic film, and the bent part can form a sharp-angled arch part area to change the battery cell from a round shape to an oval shape, so that the diameter of the battery cell is increased by at least 0.4mm, and the effective utilization space is reduced; meanwhile, the process difficulty of the oval structure is increased during subsequent trimming, and the qualification rate of products is reduced.

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 discloses an one of the aim at: the utility model provides a pole piece for button cell, solves the problem that the aluminium-plastic film that breaks easily leads to leaking liquid to rise gas of the department of buckling of current laminate polymer button cell utmost point ear.

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

a pole piece for a button cell, comprising:

a current collector;

the tab is provided with tab glue, one end part of the tab is provided with a welding area, and the tab is welded on the current collector through the welding area;

at least one part of the tab glue is overlapped with the current collector, and a bendable flexible part is formed between the welding area and the tab glue.

The utility model discloses a button cell overlaps with the mass flow body with the at least partly setting that utmost point ear glued, and sets up the weld zone of utmost point ear in tip position, can form flexible portion in order to buckle from this between weld zone and the utmost point ear glue, and the setting of this flexible portion has ensured that utmost point ear is directly to carry out the level and buckles and highly being less than electric core of department of buckling. Namely, when the aluminum plastic film is packaged, the overlapped part of the tab glue and the current collector is bent along with the overlapped part of the tab glue and is led out from the side edge of the aluminum plastic film, so that the extrusion breakage of the aluminum plastic film caused by the sharp corner area formed by bending the tab from the top is avoided. Compare in conventional button cell and glue the setting with utmost point ear outside the mass flow body, and buckle through utmost point ear area between utmost point ear glue and the mass flow body, the pole piece that this button cell adopted has thoroughly solved utmost point ear department of buckling and has broken the plastic-aluminum membrane and lead to leaking the problem that rises gas, and the department of buckling is direct to be drawn forth by the side and has also avoided plastic-aluminum membrane or outside extrusion to cause the easy cracked problem of department of buckling greatly simultaneously.

Preferably, the tab glue is provided with a first side edge, and the first side edge is a side edge of the tab glue opposite to the welding area; the current collector is provided with a second side edge, and the second side edge is a long side edge close to the tab leading-out end; the first side with distance between the second side is more than or equal to 0.5mm, and is less than the width of mass flow body. The width of the overlapping area of the tab glue and the current collector is set to be at least more than 0.5mm, so that the tab can be ensured to have enough bending areas, the leading-out position of the tab and the aluminum-plastic film have enough distance, and the situation that the aluminum-plastic film is broken due to the fact that the bending position at the top is further avoided.

Preferably, the distance between the first side edge and the second side edge is 0.5-5 mm. More preferably, the distance between the first side edge and the second side edge is 1 mm. The inventor finds that when the distance between the first side and the second side is 1mm through repeated experiments on a large number of button cells with different shapes, models and capacities, namely the length of the overlapping area of the tab glue and the current collector is 1mm, the performance of the button cell is more excellent, the problem that an aluminum-plastic film is broken by extrusion can be avoided when the distance is long, and meanwhile, the energy density of the cell is increased.

Preferably, a welding spot array is formed on the welding area, the diameter of each welding spot is 0.01-0.5 mm, and the distance between every two adjacent welding spots is 0.01-1 mm. The diameter of the welding spot of the welding area is reduced to be less than 0.5mm, and the distance between the welding spots is reduced, so that when enough contact is ensured between the lug and the current collector, the situation that the welding head falls off due to long-term use of the button cell can be prevented, and the reliability of connection between the lug and the pole piece is effectively improved. In addition, the arrangement increases the current concentrated on the surface, so that the conductivity of the battery is more excellent.

The conventional button battery is bent through the outer area of a current collector, and the problems of adjusting the size and distance of welding spots are not considered; meanwhile, the tab glue is hard to bend due to high hardness, and the tab glue can be moved out of the current collector through a common design. The inventor breaks through the conventional design idea, at least one part of the tab glue and the current collector is overlapped, and the tab glue and the welding area are used for positioning, so that the tab can be directly bent from the flexible part and directly led out from the side edge of the aluminum-plastic film without bypassing the top of the aluminum-plastic film and then led out, and the risk potential hazard of puncturing the aluminum-plastic film due to the fact that a sharp corner is led out from the top is avoided.

The utility model discloses a second of purpose lies in: the utility model provides a button cell, include by any one of the aforesaid pole piece coiling electric core and the parcel that forms be in the outer plastic-aluminum membrane of electric core, the plastic-aluminum membrane includes first plastic-aluminum diaphragm and second plastic-aluminum diaphragm, utmost point ear passes through flexible portion level is buckled and is followed first plastic-aluminum diaphragm with second plastic-aluminum diaphragm lid closes the department and outwards extends.

The button cell of the utility model not only solves the risk hidden danger that the sharp corner brought by the bending area at the top part punctures the aluminum plastic film; meanwhile, the tabs are directly led out from the side edge of the aluminum-plastic film, the situation that the diameter of the battery cell is increased due to sharp corners is avoided, the effective utilization space of the button battery can be increased to a greater extent, and the capacity reaches the limit; in addition, when the utmost point ear is cut edge after accomplishing the parcel of plastic-aluminum membrane, also can not lead to electric core to become oval-shaped situation by circular because of the diameter increases, reduced the technology degree of difficulty of cutting edge, improved the qualification rate of product, still make the battery see more pleasing to the eye on the whole.

Preferably, the distance between the tab extending outwards and the top end of the first aluminum-plastic membrane is a, the distance between the tab extending outwards and the bottom end of the second aluminum-plastic membrane is b, and a: b is (1-20): 20-1.

Preferably, an insulating film is further attached to the outer ring of the battery cell, and the welding area is coated by the insulating film; the width of the insulating film is substantially equal to the height of the land. Compare in traditional full cladding situation, the utility model discloses carry out the coiling with the insulating film around the weld zone, be close to the flexible portion with the insulating film promptly and set up, when carrying out flexible portion and buckling, the insulating film also can play the effect of location to help the better buckling of flexible portion. Specifically, the insulating film may be applied by green glue.

Preferably, the pole piece comprises a positive pole piece and a negative pole piece, the tab comprises a positive pole tab and a negative pole tab, the positive pole tab is electrically connected with the positive pole piece, the negative pole tab is electrically connected with the negative pole piece, and the included angle between the positive pole tab and the negative pole tab relative to a connecting line of the winding center is 0-180 ℃. The positive tab is connected to one end of the positive plate far away from the axis of the battery core at the outermost ring of the battery core, and the negative tab is connected to one end of the negative plate far away from the axis of the battery core at the outermost ring of the battery core.

Preferably, the lengths of the negative plate and the positive plate at the outermost ring of the battery core are different. Through the staggered arrangement with different lengths, the positive and negative electrode tabs can be led out from any direction and any angle according to the specific shape of the button battery, for example, the included angle between the positive electrode tab and the negative electrode tab relative to the connecting line of the winding center can be 30 ℃, 60 ℃, 90 ℃, 180 ℃ and the like, and certainly, the included angle is not limited to the angle for explaining the specification.

Compared with the prior art, the utility model discloses following beneficial effect has at least:

1) the utility model provides a pole piece for button cell, which comprises a current collector; the tab is provided with tab glue, one end part of the tab is provided with a welding area, and the tab is welded on the current collector through the welding area; at least one part of the tab glue is overlapped with the current collector, and a bendable flexible part is formed between the welding area and the tab glue. Compare in conventional button cell and glue the setting with utmost point ear outside the mass flow body, and buckle through utmost point ear area between utmost point ear glue and the mass flow body, the utility model discloses a pole piece for button cell then overlaps with the mass flow body with at least some setting that utmost point ear glued, and sets up the weld zone of utmost point ear in tip position, can form the flexible portion that can buckle from this between weld zone and the utmost point ear glue, and the setting of this flexible portion has guaranteed that utmost point ear is directly to carry out the level and buckle and highly being less than electric core of department. Therefore, when the aluminum plastic film is packaged, the lug is directly bent from the flexible part and led out from the side edge of the aluminum plastic film, the risk potential danger that the lug is broken due to the fact that the lug is bent from the top to form a sharp corner area, and the problem that the aluminum plastic film is broken easily at the bent part of the lug of the existing soft package button battery to cause liquid leakage and air inflation is solved thoroughly.

2) The utility model also provides a button cell, include the electric core and the parcel that are formed by the coiling of above-mentioned pole piece and be in the outer plastic-aluminum membrane of electric core, the plastic-aluminum membrane includes first plastic-aluminum diaphragm and second plastic-aluminum diaphragm, utmost point ear passes through flexible portion level is buckled and is followed first plastic-aluminum diaphragm with second plastic-aluminum diaphragm lid closes the department and outwards extends. The button cell of the utility model not only solves the risk hidden danger that the sharp corner brought by the bending area at the top part punctures the aluminum plastic film; meanwhile, the tab is directly led out from the side edge of the aluminum-plastic film, so that the bent part of the tab is infinitely close to the battery cell, the situation that the diameter of the battery cell is increased due to sharp corners does not exist, the effective utilization space of the button battery can be increased to a greater extent, and the capacity reaches the limit; in addition, when the package of accomplishing the plastic-aluminum membrane was cut edge to utmost point ear, also can not appear leading to electric core to become oval-shaped situation by circular because of the diameter increases, reduced the technology degree of difficulty of cutting edge, improved the qualification rate of product, still make the battery see more pleasing to the eye on the whole.

Drawings

Fig. 1 is a schematic structural diagram of a conventional button battery after being wound.

Fig. 2 is a schematic structural diagram of the pole piece of the present invention.

Fig. 3 is one of the schematic structural diagrams of the button cell of the present invention after being wound.

Fig. 4 is a schematic sectional view of the button cell of the present invention after being wound.

Fig. 5 is a second schematic structural view of the button battery according to the present invention after being wound.

In the figure: 1-pole piece; 11-a current collector; 111-a second side; 12-a tab; 121-a weld area; 1211-spot of solder; 122-a flexible portion; 123-positive tab; 124-negative tab; 13-tab glue; 131-a first side edge; 14-positive plate; 15-negative plate; 2-electric core; 21-a separator; 3-an insulating film.

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 "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, detachably connected, or integral to one another; 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.

Example 1

As shown in fig. 2, a pole piece for a button cell includes:

a current collector 11;

a tab 12 provided with a tab paste 13, one end of the tab 12 having a welding region 121, the tab 12 being welded to the current collector 11 via the welding region 121;

at least a portion of the tab paste 13 overlaps the current collector 11, and a bendable flexible portion 122 is formed between the welding region 121 and the tab paste 13.

Further, the welding of the tab 12 and the current collector 11 may be performed by laser welding or ultrasonic welding, preferably ultrasonic welding, to control the size of the welding point 1211 more precisely. The tab glue 13 can be partially overlapped with the current collector 11 or completely overlapped with the current collector 11, and only the subsequent tab glue 13 can be ensured to be extended to the sealing position of the aluminum plastic film, so as to play an insulating role; preferably, the tab glue 13 partially overlaps the current collector 11. The tab glue 13 can be set to be square as usual, and the shape of the tab glue can be changed according to the actual requirements of button batteries or special-shaped batteries, such as round, oval and the like. The materials of the current collector 11, the tab 12 and the tab glue 13 are changed according to the difference of the anode and cathode, for example, the tab material can be aluminum, copper, nickel, etc., and the thickness can be set to 0.05-0.2 mm.

Further, the tab compound 13 has a first side 131, and the first side 131 is a side of the tab compound 13 opposite to the welding region 121; the current collector 11 has a second side 111, and the second side 111 is a long side close to the lead-out end of the tab 12; the distance between the first side 131 and the second side 111 is greater than or equal to 0.5mm and less than the width of the current collector 11. Preferably, the distance between the first side 131 and the second side 111 is 0.5-5 mm; more preferably, the distance between the first side 131 and the second side 111 is 1 mm. The width of the overlapping area of the tab glue 13 and the current collector 11 is set to be at least more than 0.5mm, so that the tab 12 can be ensured to have enough bending area, the lead-out position of the tab and the aluminum-plastic film have enough distance, and the situation that the aluminum-plastic film is broken due to the bending sharp corner at the top is further avoided. Moreover, the inventor of the present invention repeatedly tests a large number of button cells with different shapes, types and capacities, and finds that when the distance between the first side 131 and the second side 111 is 1mm, that is, the length of the overlapping area of the tab glue 13 and the current collector 11 is 1mm, the performance of the button cell is more excellent, which indicates that not only can the aluminum plastic film be prevented from being broken by extrusion at the distance, but also the energy density of the cell can be increased.

Further, as shown in fig. 2, the bonding pad 121 is formed with an array of pads 1211, the diameter of the pad 1211 is 0.01 to 0.5mm, and the distance between two adjacent pads 1211 is 0.01 to 1 mm. The welding area 121 may be formed in a square, a circle, or other shapes as a whole, and may be designed according to actual requirements. The diameter of the welding points 1211 is reduced to be less than 0.5mm, and the distance between the welding points 1211 is reduced, so that the condition that a welding head falls off due to long-term use of a button battery can be prevented while the requirement that the lug 12 is in sufficient contact with the current collector 11 is met, and the reliability of connection between the lug 12 and the current collector 11 is effectively improved. Compare in conventional battery, under the same welding area, the utility model discloses a between the solder joint 1211 inseparabler, general surface area is bigger, and is also bigger with the area of contact of mass flow body 11, and this type is similar to the "skin effect" of wire, concentrates on the electric current on surface also to increase thereupon for the electric conductivity of battery is also more excellent. In addition, the effect of welding in the aspect of heat dissipation of little solder joint is more excellent, so help delaying the intensification of battery when the multiplying power discharges, guarantee the stability of battery performance.

Example 2

As shown in fig. 3-5, a button cell includes embodiment 1 pole piece 1 coil and form electric core 2 and the plastic-aluminum membrane of parcel outside electric core 2, the plastic-aluminum membrane includes first plastic-aluminum membrane piece and second plastic-aluminum membrane piece, utmost point ear 12 through flexible portion 122 horizontal bending and along first plastic-aluminum membrane piece and the outside extension of second plastic-aluminum membrane piece lid department of closing. The shape of the first aluminum-plastic membrane and the shape of the second aluminum-plastic membrane of the aluminum-plastic membrane can be adaptively changed according to the shape of the button battery, such as circular or square, but the first aluminum-plastic membrane and the second aluminum-plastic membrane are matched to meet the requirement of a follow-up packaged battery cell.

Preferably, the distance between the tab 12 extending outwards and the top end of the first aluminum plastic film is a, the distance between the tab 12 extending outwards and the bottom end of the second aluminum plastic film is b, and a: b is (1-20): 20-1. The depth of the first aluminum-plastic membrane and the depth of the second aluminum-plastic membrane can be determined according to the distance ratio of the tab to the second aluminum-plastic membrane, preferably, the depth of the second aluminum-plastic membrane can be designed to be larger than the depth of the first aluminum-plastic membrane, so that the ratio of the tab to the second aluminum-plastic membrane is 1 (4-8), specifically, the distance a between the tab 12 extending outwards and the top end of the first aluminum-plastic membrane can be 1mm, and the distance b between the tab 12 extending outwards and the bottom end of the second aluminum-plastic membrane can be 4.4 mm. More preferably, the depth of the second aluminum-plastic film sheet can be designed to be slightly larger than that of the first aluminum-plastic film sheet, so that the outward extending tab is led out from the middle area of the aluminum-plastic film.

Preferably, the outer ring of the battery cell 2 is further coated with an insulating film 3, the insulating film 3 covers the welding area 121, and the width of the insulating film 3 is substantially equal to the height of the welding area 121. After the winding of the electric core 2 is completed, an insulating film 3 is attached to the surface of the outer ring of the electric core to fix the electric core. And simultaneously, the utility model discloses an insulating film 3 still has the function of location, is close to flexible portion 122 with insulating film 3 and carries out the coiling setting around weld region 121, can help the better buckling of flexible portion 122 through weld region 121 and insulating film 3's collective positioning effect, mainly removes the function that realizes the location through insulating film 3's width control. Specifically, the insulating film 3 can be coated with green glue, and the width of the green glue is preferably 2-7 mm.

Preferably, the pole piece 1 comprises a positive pole piece 14 and a negative pole piece 15, the tab 12 comprises a positive pole tab 123 and a negative pole tab 124, the positive pole tab 123 is electrically connected with the positive pole piece 14, the negative pole tab 124 is electrically connected with the negative pole piece 15, and an included angle between the positive pole tab 123 and the negative pole tab 124 and a connecting line of a winding center is 0-180 ℃; the lengths of the negative plate 15 and the positive plate 14 at the outermost circle of the battery cell 2 are different. The battery cell 2 is formed by sequentially winding a positive plate 14, a diaphragm 21 and a negative plate 15. After the aluminum-plastic film is wrapped, the side edges of the tabs 12 on the side edges of the aluminum-plastic film can be cut firstly, the tabs 12 are folded back after being cut to a proper length, and the tabs 12 can be led out from two ends or one end of the tabs 12 after being folded back according to the difference of the lengths of positive and negative pole piece current collectors of the outermost circle of the battery cell 2. Referring to fig. 3 and 5, the included angle between the positive tab 123 and the negative tab 124 with respect to the connecting line of the winding center may be selected according to actual production requirements; and after the pole lug 12 is folded back, the design of the button cell can be completed.

Example 3

The embodiment provides a preparation method of a button cell, which comprises the following steps:

s1, welding the tab 12 to the current collector 11 via the welding area 121;

s2, attaching tab glue 13 to the tab 12 and close to the welding area 121, so that at least a part of the tab glue 13 overlaps the current collector 11, and a flexible portion 122 is reserved between the welding area 121 and the tab glue 13;

s3, respectively carrying out pit punching treatment on the first aluminum-plastic membrane and the second aluminum-plastic membrane;

s4, placing the battery cell 2 in a pit of a second aluminum-plastic membrane, and then covering the first aluminum-plastic membrane along the direction of the second aluminum-plastic membrane, so that the tab is horizontally bent by the flexible part 122 and extends outwards along the covering position of the first aluminum-plastic membrane and the second aluminum-plastic membrane, and the packaging of the aluminum-plastic membrane is completed;

and S5, after the packaging is finished, folding the tab 12 back to finish the preparation of the button cell.

Specifically, with first plastic-aluminum diaphragm and second plastic-aluminum diaphragm towards the hole after handling, arrange electric core 2 in the second plastic-aluminum diaphragm pit, utilize first plastic-aluminum diaphragm to cover when pouring into electrolyte and close encapsulation electric core 2, later become electric core 2 and two seals of bleeding, then cut edge to utmost point ear according to the battery size requirement of reality to prevent utmost point ear overlength and be unfavorable for subsequent encapsulation. After trimming is finished, the electrode lugs are folded back, and the folding back direction and shape of the electrode lugs can be set according to the actual requirements of the battery; and finishing the preparation of the button cell.

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 pole piece for a button cell, comprising:

a current collector (11);

the electrode tab (12) is provided with an electrode tab glue (13), one end part of the electrode tab (12) is provided with a welding area (121), and the electrode tab (12) is welded on the current collector (11) through the welding area (121);

wherein at least one part of the tab glue (13) is overlapped with the current collector (11), and a bendable flexible part (122) is formed between the welding area (121) and the tab glue (13).

2. The pole piece for button cell according to claim 1, characterized in that:

the tab glue (13) is provided with a first side edge (131), and the first side edge (131) is the side edge of the tab glue (13) opposite to the welding area (121);

the current collector (11) is provided with a second side edge (111), and the second side edge (111) is a long side edge close to the leading-out end of the tab (12);

the distance between the first side edge (131) and the second side edge (111) is greater than or equal to 0.5mm, and is less than the width of the current collector (11).

3. Pole piece for a button cell according to claim 2, characterized in that the distance between the first side (131) and the second side (111) is 0.5-5 mm.

4. The pole piece for button cell as claimed in claim 1, wherein the welding area (121) is formed with an array of welding spots (1211), the diameter of the welding spot (1211) is 0.01-0.5 mm, and the distance between two adjacent welding spots (1211) is 0.01-1 mm.

5. A button cell is characterized by comprising an electric core (2) formed by winding a pole piece (1) according to any one of claims 1 to 4 and an aluminum plastic film wrapped outside the electric core (2), wherein the aluminum plastic film comprises a first aluminum plastic film sheet and a second aluminum plastic film sheet, and a tab (12) is horizontally bent through the flexible part (122) and extends outwards along the covering position of the first aluminum plastic film sheet and the second aluminum plastic film sheet.

6. The button cell according to claim 5, wherein the distance between the tab (12) extending outwards and the top end of the first aluminum-plastic film is a, the distance between the tab (12) extending outwards and the bottom end of the second aluminum-plastic film is b, and a: b ═ 1-20: 20-1.

7. The button battery according to claim 5, characterized in that the outer ring of the electric core (2) is further coated with an insulating film (3), and the insulating film (3) covers the welding area (121).

8. The button cell according to claim 5, characterized in that the pole piece (1) comprises a positive pole piece (14) and a negative pole piece (15), the tab (12) comprises a positive pole tab (123) and a negative pole tab (124), the positive pole tab (123) is electrically connected with the positive pole piece (14), the negative pole tab (124) is electrically connected with the negative pole piece (15), and the included angle between the positive pole tab (123) and the negative pole tab (124) relative to the connecting line of the winding centers of the cells (2) is 0-180 ℃.

9. The button battery according to claim 8, characterized in that the lengths of the negative pole piece (15) and the positive pole piece (14) at the outermost circle of the battery core (2) are different.