CN220856844U - Secondary battery, battery pack, and electronic device - Google Patents

Abstract

The utility model provides a secondary battery, a battery pack and an electronic device, wherein the secondary battery comprises: a case, an electrode assembly, an end cap, a post, a first current collecting member and a second current collecting member; the housing includes an end wall and a side wall, the side wall being formed with an opening; the electrode assembly is arranged in the shell, and the center of the electrode assembly comprises a winding core through hole; the end cover is arranged at the opening side to seal the opening; the pole is connected with the end cover; the first current collecting member is arranged on one side of the electrode assembly facing the opening, and is electrically connected with the electrode assembly and the pole; the second current collecting member is electrically connected with the electrode assembly and fixedly connected with the case; the second current collecting component is provided with a first through hole, and the projection of the first through hole, the projection of the winding core through hole and the projection of the pole connecting area are overlapped in at least partial areas. The secondary battery can solve the technical problem of high production cost caused by complex assembly procedures and low assembly efficiency in the assembly process of the secondary battery.

Description

Secondary battery, battery pack, and electronic device

Technical Field

The utility model relates to the technical field of batteries, in particular to a secondary battery, a battery pack and electronic equipment.

Background

With the development of the electric automobile industry, the application of the secondary battery is becoming more and more widespread. At present, the number of parts in the secondary battery is large, and the design of various parts and the assembly process of the secondary battery have a crucial influence on the production cost and the production efficiency.

The conventional secondary battery generally comprises welding the flattened tab with a current collecting member, welding the current collecting member with one end of a connecting sheet, welding the other end of the connecting sheet with a pole on an end cover, folding the connecting sheet, loading the folded connecting sheet into a housing, and finally welding the end cover with the housing. The traditional scheme has the advantages of more assembly parts, complex assembly procedures, lower assembly efficiency and higher production cost; and the bending force of the connecting sheet is not easy to control in the folding process, and the problem that the connecting sheet is broken to cause failure of electric connection is easy to occur.

Disclosure of utility model

In view of the above drawbacks of the prior art, the present utility model provides a secondary battery, a battery pack, and an electronic device, so as to improve the technical problem of high production cost caused by complex assembly process and low assembly efficiency in the process of assembling the secondary battery.

To achieve the above and other related objects, the present utility model provides a secondary battery comprising: a case, an electrode assembly, an end cap, a post, a first current collecting member and a second current collecting member; the shell comprises an end wall and a side wall surrounding the end wall, and an opening is formed on one side of the side wall, which faces away from the end wall; the electrode assembly is arranged in the shell, and the center of the electrode assembly comprises a winding core through hole; the end cover is arranged on the opening side and is welded with the side wall to seal the opening; the pole penetrates through the end cover and is in insulating connection with the end cover, and one side of the pole, which is positioned in the shell, comprises a first flat part; the first current collecting member is arranged on one side of the electrode assembly facing the opening, the first current collecting member is electrically connected with the electrode assembly, the first current collecting member comprises a second flat part corresponding to the first flat part, and the second flat part is welded with the first flat part; the second current collecting member is at least partially arranged on one side of the electrode assembly, which is close to the end wall, and is electrically connected with the electrode assembly and fixedly connected with the shell; the second current collecting component is provided with a first through hole, and the orthographic projection of the first through hole, the orthographic projection of the winding core through hole and the orthographic projection of the pole connecting area are at least partially overlapped along the height direction of the secondary battery.

In an example of the secondary battery of the present utility model, the first current collecting member is of a flat sheet structure, and the second flat portion covers the winding core through hole.

In one example of the secondary battery of the present utility model, the end wall includes a thinned region that is in contact with the second current collecting member and welded and fixed.

In an example of the secondary battery of the present utility model, a first solder is provided on a wall of the thinned region facing away from the second current collecting member, and the first solder is provided around the first through hole.

In an example of the secondary battery of the present utility model, the end wall includes a second through hole, and a side of the second through hole facing away from the electrode assembly includes a first stepped hole; the second current collecting member comprises a connecting part, the connecting part is arranged in the second through hole in a penetrating way, one side of the connecting part, which is away from the electrode assembly, comprises a flanging part, and the flanging part is abutted against the step surface of the first step hole and is welded and fixed; the secondary battery further includes a cap plate covering the second through hole.

In one example of the secondary battery of the present utility model, the end cap includes a liquid injection hole, and an explosion-proof valve is mounted on the liquid injection hole.

In an example of the secondary battery of the present utility model, the burring includes at least one notch in the circumferential direction of the first through hole.

In an example of the secondary battery of the present utility model, the second through hole further includes a second stepped hole at a side of the first stepped hole facing away from the electrode assembly, and the cap plate abuts against a stepped surface of the second stepped hole in a height direction of the secondary battery.

In an example of the secondary battery of the present utility model, the height of the first stepped hole is greater than or equal to the thickness of the burring in the height direction of the secondary battery.

The utility model also provides a battery pack comprising any one of the secondary batteries described above.

The utility model further provides electronic equipment, which comprises the battery pack.

The secondary battery provided by the utility model is characterized in that a first through hole is formed in a second current collecting member, and at least partial areas of orthographic projection of the first through hole, orthographic projection of a winding core through hole and orthographic projection of a pole connecting area are overlapped; therefore, the welding tool can extend into the first through hole, torque welding is conducted between the first flat part and the second flat part, and welding connection between the first current collecting member and the pole installed on the end cover is completed. According to the structure, before the electrode assembly is put into the shell, the first current collecting member and the second current collecting member are welded at two ends of the electrode assembly respectively, and then the pole column and the first current collecting member are subjected to torque welding, so that the fixed connection between the end cover and the electrode assembly is completed outside the shell; and then the electrode assembly and the end cover are put into the shell together, so that the end cover is covered and sealed at the opening of the shell, finally, the second current collecting member and the shell are welded outside the shell respectively, the end cover and the side wall of the shell are welded, and finally, the whole secondary battery is assembled. Unlike the conventional secondary battery assembly process, the secondary battery in this embodiment omits the connection piece in the step of electrically connecting the electrode post and the electrode assembly, and does not need to perform folding operation on the connection piece, so that the number of parts is reduced, the assembly process is simplified, the assembly efficiency of the secondary battery can be improved, and the production cost of the secondary battery is reduced.

Drawings

In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings that are necessary for the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the utility model and that other embodiments may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic view showing the overall external configuration of an embodiment of a secondary battery according to the present utility model;

Fig. 2 is a partial structural sectional view of an embodiment of the secondary battery of the present utility model;

FIG. 3 is an enlarged view of a portion of area A of FIG. 2;

FIG. 4 is an enlarged view of a portion of region B of FIG. 2;

fig. 5 is a schematic view showing a three-dimensional structure in which the end wall of the case is provided with a thinned region in an embodiment of the secondary battery of the present utility model;

fig. 6 is a partial structural sectional view of an end wall of a case provided with a thinned region in an embodiment of a secondary battery according to the present utility model;

FIG. 7 is an enlarged view of a portion of region C of FIG. 6;

fig. 8 is a partial structural sectional view of another embodiment of the secondary battery of the present utility model;

FIG. 9 is an enlarged partial view of region D of FIG. 8;

Fig. 10 is a schematic view showing a structure in which a second through hole is formed in an end wall of a secondary battery according to an embodiment of the present utility model;

FIG. 11 is an enlarged view of a portion of area E of FIG. 10;

fig. 12 is a schematic view showing the overall structure of a second current collecting member in an embodiment of the secondary battery according to the present utility model;

Fig. 13 is a cross-sectional view of the second current collecting member shown in fig. 12;

FIG. 14 is a schematic view showing the overall structure of an embodiment of a battery pack according to the present utility model;

fig. 15 is a schematic view showing a structure in which the battery pack of the present utility model is mounted on a vehicle.

Description of element reference numerals

100. A secondary battery; 110/110', housing; 111. a sidewall; 112/112', end walls; 1121. thinning the area; 1122. a first solder printing; 1123. a second through hole; 11231. a first stepped hole; 112311, a first step surface; 11232. a second stepped hole; 112321, a second step surface; 113. an opening; 120. an electrode assembly; 121. a winding core through hole; 122. a first tab; 123. a second lug; 130. an end cap; 131. a first mounting hole; 1311. an insulation gap; 1312. a liquid injection hole; 1313. an explosion-proof valve; 140. a pole; 141. a column portion; 142. a first fixing portion; 143. a second fixing portion; 144. a first flat portion; 151. a first current collecting member; 1511. a second flat portion; 1512. a first current collecting body; 1513. a tab connection region; 152/152', a second current collecting member; 1521. a first through hole; 1522. a connection part; 1523. a burring part; 15231. a notch; 15232. a second solder printing; 1524. a second current collecting body; 160. a cover plate; 170. a first insulating member; 180. a second insulating member; 190. a seal; 200. a battery pack; 210. a case; 211. a first box portion; 212. a second box portion; 300. an electronic device; 310. a working part.

Detailed Description

Other advantages and effects of the present utility model will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present utility model with reference to specific examples. The utility model may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present utility model. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict. It is also to be understood that the terminology used in the examples of the utility model is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the utility model. The test methods in the following examples, in which specific conditions are not noted, are generally conducted under conventional conditions or under conditions recommended by the respective manufacturers.

Where numerical ranges are provided in the examples, it is understood that unless otherwise stated herein, both endpoints of each numerical range and any number between the two endpoints are significant both in the numerical range. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs and to which this utility model belongs, and any method, apparatus, or material of the prior art similar or identical to the methods, apparatus, or materials of the embodiments of the utility model may be used to practice the utility model.

It should be understood that the terms such as "upper," "lower," "left," "right," "middle," and "a" and the like are used in this specification for descriptive purposes only and not for purposes of limitation, and that the utility model may be practiced without materially departing from the novel teachings and without departing from the scope of the utility model.

Referring to fig. 1 to 15, the present utility model provides a secondary battery 100, a battery pack 200, and an electronic device 300, in which the secondary battery 100 reduces the number of assembly parts, simplifies assembly processes, and thus can improve assembly efficiency and reduce production costs of the secondary battery 100.

Referring to fig. 1 to 6, the structure of the secondary battery 100 will be further described, the secondary battery 100 including: the electrode assembly includes a case 110, an electrode assembly 120, an end cap 130, a post 140, a first current collecting member 151, and a second current collecting member 152. The case 110 has a receiving chamber formed therein for receiving the electrode assembly 120, an electrolyte (not shown), and other components, and the case 110 may have an opening 113 at one end or may have openings 113 at both ends. The housing 110 may be of various shapes, such as a cylindrical shape, a prismatic shape, etc. The specific dimensions of the case 110 may be determined according to the specific dimensions of the electrode assembly 120, for example, specifications of 46mm in diameter, 80mm in height, 95mm, 120mm, etc. The material of the housing 110 may be various, such as copper, iron, aluminum, steel, aluminum alloy, etc., and in order to prevent the housing 110 from rusting during long-term use, a layer of rust-preventing material, such as metallic nickel, etc., may be plated on the surface of the housing 110. In this embodiment, the housing 110 is made of aluminum.

Referring to fig. 1, 2, 5 and 6, in an example of the secondary battery 100 of the present utility model, the case 110 has a cylindrical structure, the case 110 includes an end wall 112 and a side wall 111 surrounding the end wall 112, the end wall 112 is a closed end, and an opening 113 opposite to the end wall 112 is an open end.

As shown in fig. 2, the electrode assembly 120 is accommodated in the case 110. The electrode assembly 120 is a component in the cell where electrochemical reactions occur. The case 110 may contain one or more electrode assemblies 120 therein. The electrode assembly 120 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is generally provided between the positive electrode sheet and the negative electrode sheet. The positive electrode plate comprises a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode current collector; the positive electrode current collector comprises a positive electrode coating area and a positive electrode lug connected to the positive electrode coating area, wherein the positive electrode coating area is coated with a positive electrode active material layer, and the positive electrode lug is not coated with the positive electrode active material layer. The negative electrode plate comprises a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode current collector; the negative electrode current collector comprises a negative electrode coating area and a negative electrode tab connected to the negative electrode coating area, wherein the negative electrode coating area is coated with a negative electrode active material layer, and the negative electrode tab is not coated with the negative electrode active material layer. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate or the like. The material of the anode current collector may be copper, the anode active material layer includes an anode active material, and the anode active material may be carbon or silicon, or the like. The separator may be made of PP (polypropylene) or PE (polyethylene). In order to protect and insulate the battery cell, the battery cell can be coated with an insulating film, and the insulating film can be synthesized by PP, PE, PET, PVC or other high polymer materials.

Referring to fig. 2, in an example of the secondary battery 100 of the present utility model, an electrode assembly 120 is mounted in a case 110, a center of the electrode assembly 120 includes a winding core through hole 121, two ends of the electrode assembly 120 in a length direction are respectively provided with a first tab 122 and a second tab 123, and polarities of the first tab 122 and the second tab 123 are opposite, wherein the first tab 122 faces one side of an opening 113, the first tab 122 is a negative tab, the second tab 123 faces one side of an end wall 112, and the second tab 123 is a positive tab. In other embodiments, the first tab 122 may be a negative tab, and the second tab 123 may be a positive tab.

Referring to fig. 2 and 3, an end cap 130 is disposed at the opening 113, and an outer circumference of the end cap 130 is welded to the sidewall 111 of the case 110 to seal the opening 113. The end cap 130 is provided with a first mounting hole 131, and the first mounting hole 131 penetrates the end cap 130 along the thickness direction of the end cap 130. The specific position of the first mounting hole 131 on the end cover 130 is not limited, and preferably, in this embodiment, the first mounting hole 131 is disposed at the center of the end cover 130, so that positioning processing of the first mounting hole 131 on the end cover 130 is facilitated. The pole 140 is inserted into the first mounting hole 131 and insulated from the end cover 130, and the mounting manner of the pole 140 on the end cover 130 is not limited as long as the insulation between the pole 140 and the end cover 130 can be achieved; in the height direction of the secondary battery 100, a side of the tab 140 located inside the case 110 includes a first flat portion 144, and a partial region of the first flat portion 144 overlaps the winding core through hole 121. The shape and the area of the first flat portion 144 are not limited, and for example, the first flat portion 144 may be circular, square, or irregular, as long as it is ensured that at least a part of the first flat portion 144 overlaps the winding core through hole 121.

Referring to fig. 2, the first current collecting member 151 is disposed on a side of the electrode assembly 120 facing the opening 113, the first current collecting member 151 includes a first current collecting body 1512, a tab connection region 1513, and a second flat portion 1511, the second flat portion 1511 is disposed in a central region of the first current collecting body 1512, the tab connection region 1513 is annularly disposed at an outer periphery of the second flat portion 1511, the tab connection region 1513 is electrically connected with the second flat portion 1511, and the electrical connection manner may be selected from, for example, welding connection, or any manner capable of achieving electrical connection between the tab connection region 1513 and the second flat portion 1511, such as integrally formed connection. In the present embodiment, in order to improve the assembly efficiency, the tab connection region 1513 and the second flat portion 1511 are integrally press-molded to be connected. The tab connection region 1513 is electrically connected to the first tab 122, and the electrical connection may be a welded connection or an adhesive connection of conductive adhesive, and in this embodiment, the tab connection region 1513 is welded to the first tab 122. The second flat portion 1511 is disposed corresponding to the first flat portion 144, that is, the first flat portion 144 and the second flat portion 1511 are in contact with at least a partial area for welding connection; thereby achieving electrical connection between the first tab 122 and the post 140.

Referring to fig. 2 and 3, the structure of the pole 140 is further described to describe the pole 140, the pole 140 in this embodiment includes a cylindrical portion 141, a first fixing portion 142 and a second fixing portion 143, the cylindrical portion 141 is a cylindrical structure, the cylindrical portion 141 penetrates through the first mounting hole 131, and the first fixing portion 142 is disposed at a circumference of an outer end (an end portion on a side facing away from the electrode assembly 120) of the cylindrical portion 141 and is clamped at an outer end (a side facing away from the electrode assembly 120) of the end cap 130; the second fixing portion 143 is provided in the circumferential direction of the inner end (end toward the electrode assembly 120 side) of the cylindrical portion 141, and is fitted inside (toward the electrode assembly 120 side) the end wall 112. The pole 140 is insulated and isolated from the end cover 130 through the first insulating member 170 and the second insulating member 180 respectively, and the sealing member 190 is pressed by the first fixing part 142 to seal the first mounting hole 131; an insulation gap 1311 is provided between the outer sidewall of the column portion 141 and the inner wall of the first mounting hole 131, thereby achieving insulation between the column portion 141 and the first mounting hole 131; in other embodiments, other insulating members may be disposed between the outer sidewall of the column portion 141 and the inner wall of the first mounting hole 131, and insulation between the column portion 141 and the first mounting hole 131 may be achieved. The first insulator 170 is installed between the first fixing part 142 and the outer wall of the end cap 130, insulating the pole 140 from the outer wall of the end cap 130; the second insulator 180 is installed between the second fixing portion 143 and the inner wall of the end cap 130, insulating the pole 140 from the inner wall of the end cap 130. The first flat portion 144 is disposed at an end of the second fixing portion 143 facing the electrode assembly 120, and the first flat portion 144 is abutted against the second flat portion 1511 and welded thereto.

Referring to fig. 2 to 4, the second current collecting member 152 is at least partially disposed on a side of the electrode assembly 120 facing the end wall 112, and one side of the second current collecting member 152 is electrically connected to the second electrode lug 123, and the electrical connection may be a welded connection or an adhesive connection of conductive adhesive, in this embodiment, one side of the second current collecting member 152 is welded to the second electrode lug 123; the other side of the second current collecting member 152 is fixedly coupled with the case 110. The fixing connection may be a variety of manners, for example, a welding connection manner, a rolling groove pressing connection manner, or the like, and in this embodiment, the second current collecting member 152 is welded with the housing 110. The second current collecting member 152 may be welded to the side wall 111 of the case 110, may be welded to the end wall 112 of the case 110, or may be welded to both the side wall 111 of the case 110 and the end wall 112 of the case 110, so long as the welded connection between the second current collecting member 152 and the case 110 is achieved. In the present embodiment, the second current collecting member 152 is welded to the end wall 112 of the case 110 for convenience of welding, ensuring reliability of the connection.

Referring to fig. 2 and 3, a first through hole 1521 is formed in a central region of the second current collecting member 152, and the front projection of the first through hole 1521, the front projection of the core through hole 121, and the front projection of the second flat portion 1511 at least partially overlap in the height direction of the secondary battery 100. The specific cross-sectional shape of the first through hole 1521 is not limited, and may be, for example, square, circular, or other polygonal shape, and the first through hole 1521 has no limitation in the distribution position on the second current collecting member 152, so long as it is ensured that the front projection of the first through hole 1521, the front projection of the winding core through hole 121, and the front projection of the second flat portion 1511 at least partially overlap.

By providing the first through hole 1521 on the second current collecting member 152, the welding tool may extend into the first through hole 1521, thereby welding the second flat portion 1511 and the first flat portion 144, and achieving torque welding between the pole 140 and the first current collecting member 151. Preferably, in the present embodiment, the cross section of the first through hole 1521 is circular, and the first through hole 1521 is disposed coaxially with the core through hole 121, and the diameter of the first through hole 1521 is close to the diameter of the core through hole 121. By the arrangement, a larger overlapping area can be obtained between the front projection of the first through hole 1521, the front projection of the winding core through hole 121 and the front projection of the second flat portion 1511, so that the specification of the welding tool which can be allowed to pass through the first through hole 1521 can be larger, and therefore, larger welding efficiency can be obtained when torque welding is carried out between the second flat portion 1511 and the first flat portion 144.

Since the secondary battery 100 in this embodiment is provided with the first through hole 1521 on the second current collecting member 152, and the welding fixture can be inserted from the first through hole 1521 to perform torque welding between the electrode post 140 and the first current collecting member 151, the secondary battery 100 in the present utility model can be assembled by an assembling method comprising the steps of:

S1, welding a first current collecting member 151 with a first tab 122, and welding a second current collecting member 152 with a second tab 123;

S2, fixedly mounting the pole 140 on the end cover 130, and simultaneously, fixing the first insulating piece and the second insulating piece on the end cover 130 to realize the insulating and fixed mounting of the pole 140 on the end cover 130; and the end cap 130 is mounted over the first tab 122 such that the first flat portion 144 abuts against the second flat portion 1511 of the first current collecting member 151;

S3, extending the welding tool into the first through hole 1521, and welding the second flat portion 1511 to realize torque welding between the pole 140 and the first current collecting member 151;

S4, mounting the electrode assembly 120 with the end cover 130, the first current collecting member 151 and the second current collecting member 152 mounted and connected into the case 110;

S5, welding the end wall 112 and the second current collecting member 152 outside the case 110, and welding the end cap 130 and the side wall 111 of the case 110, thereby completing the assembly of the secondary battery 100.

As can be seen from the above-described method of assembling the secondary battery 100, in the present application, the post 140 mounted on the end cap 130 can be directly welded to the first tab 122 through the first current collecting member 151 without mounting a connection tab therebetween, and the process of folding the connection tab is omitted, so that the number of parts can be reduced, and the assembly process is simplified, thereby improving the assembly efficiency of the secondary battery 100 and reducing the production cost; meanwhile, as the welding connection between the electrode assembly 120 and the first current collecting member 151, the second current collecting member 152 and the electrode post 140 and the end cover 130 is completed at the outer side of the case 110 when the secondary battery 100 is assembled, the arrangement is convenient to clean welding slag in the welding process, reduces the influence of the welding slag entering the inside of the case 110 to the circulation of electrolyte, and is beneficial to improving the cycle service life of the secondary battery 100; in addition, since the welding between the end cap 130 and the side wall 111 and the welding between the end wall 112 and the second current collecting member 152 are all performed outside the case 110 after the electrode assembly 120 is mounted inside the case 110, the probability of the welding slag entering the inside of the case 110 during the welding process can be further reduced, and the normal cycle life of the secondary battery 100 can be further ensured.

The secondary battery 100 according to the present utility model is configured such that the first through hole 1521 is provided in the second current collecting member 152, and the front projection of the first through hole 1521, the front projection of the winding core through hole 121, and the front projection of the second flat portion 1511 are overlapped at least in part, whereby a welding tool can be inserted into the first through hole 1521, and the second flat portion 1511 at the other end and the first flat portion 144 are torque-welded to complete the welded connection between the first current collecting member 151 and the post 140 fixed to the end cap 130. In this structural arrangement, the first current collecting member 151 and the second current collecting member 152 may be welded to both ends of the electrode assembly 120, respectively, before the electrode assembly 120 is put into the case, and then the electrode post 140 and the first current collecting member 151 are torque-welded, thereby completing the fixed connection between the end cap 130 and the electrode assembly 120 at the outside of the case 110; the electrode assembly 120 is then assembled into the case 110 together with the cap 130 such that the cap 130 covers the opening 113 of the case 110, and finally the end wall 112 of the case 110 and the second current collecting member 152 are welded to each other at the outside of the case 110, and the cap 130 is welded to the side wall 111 of the case 110, thereby completing the assembly of the entire secondary battery 100. Unlike the conventional assembly process of the secondary battery 100, the secondary battery 100 in this embodiment omits the connection tab in the electrical connection link between the electrode post 140 and the electrode assembly 120, and does not require the folding operation of the connection tab, thereby reducing the number of parts, simplifying the assembly process, improving the assembly efficiency of the secondary battery 100, and reducing the production cost of the secondary battery 100.

Referring to fig. 2 and 3, in an example of the secondary battery 100 of the present utility model, the first collecting member 151 has a flat sheet structure, and the second flat portion 1511 covers the core through-hole 121. By this arrangement, the area of the winding core through hole 121 can be utilized to the maximum extent, so that a larger welding area can be conveniently obtained between the first flat portion 144 and the second flat portion 1511, which is advantageous for improving the stability of the welding connection between the pole 140 and the first current collecting member 151. The flat sheet structure may be a completely planar structure on the upper and lower surfaces of the first current collecting member 151, or may be a planar structure on a partial region of the upper and lower surfaces of the first current collecting member 151, and a partial region may be a concave-convex structure, but the entire upper surface of the first current collecting member 151 may be a flat sheet structure. In this embodiment, the upper and lower surfaces of the first current collecting member 151 are entirely planar, so that the structure provided with the first current collecting member 151 is simple and convenient to form, and occupies a small space in the height direction of the secondary battery 100, which is advantageous in improving the volumetric energy density of the secondary battery 100. When welding the end wall 112 to the second current collecting member 152, the welding manner may be selected from resistance welding, laser penetration welding, ultrasonic welding, etc.; preferably, in this embodiment, the end wall 112 and the second current collecting member 152 are welded by laser penetration welding. Since the end wall 112 generally needs to have a certain strength and rigidity, a certain thickness is required, and thus the thickness of the end wall 112 is generally greater than the thickness of the second current collecting member 152, the welding effect of laser penetration welding is poor when welding from the end wall 112 side, and in order to improve the welding effect of laser penetration welding, referring to fig. 2 to 7, in an example of the secondary battery 100 according to the present utility model, the end wall 112 includes a thinned region 1121, the thinned region 1121 has a surface that can be exposed to the outside of the end wall 112, and the shape of the thinned region 1121 is not limited, and may be square, circular or irregular, for example, as long as it has a sufficient welding area to meet the welding requirement between the second current collecting member 152 and the end wall 112. The side of the thinned region 1121 facing the electrode assembly 120 is in contact with the second current collecting member 152 and is welded to the side of the second current collecting member 152 facing away from the electrode assembly 120.

The distribution position of the thinned region 1121 on the end wall 112 is not limited, and may be, for example, distributed in the central region of the end wall 112, or may be distributed in the edge region of the end wall 112, but preferably, referring to fig. 3, 4, 6 and 7, in an example of the secondary battery 100 according to the present utility model, the thinned region 1121 is the central region of the end wall 112, the wall body of the thinned region 1121 facing away from the second current collecting member 152 is formed with the first solder marks 1122, and the first solder marks 1122 are disposed around the first through holes 1521. The first solder marks 1122 are annularly arranged around the first through holes 1521 to form a closed pattern structure, such as a ring shape, a square ring shape, etc.; a semi-closed structure surrounding in a C-shaped structure is also possible as long as only the distribution of the welding stress of the second current collecting member 152 in the circumferential direction can be improved. In this embodiment, the first solder 1122 is disposed around the first through hole 1521 to form a closed ring structure. By the arrangement, the second current collecting member 152 can obtain uniform welding stress in the circumferential direction of the first through hole 1521, stress deformation generated by the second current collecting member 152 is reduced, and stability of welding connection of the second current collecting member 152 is improved. Preferably, referring to fig. 3, 4, 6 and 7, in another embodiment of the present utility model, the thinned region 1121 has a circular structure coaxially disposed with the first through hole 1521, so as to further improve the welding stress generated on the second current collecting member 152, reduce the stress deformation, and further improve the stability of the welding connection of the second current collecting member 152.

Referring to fig. 8 to 13, in an example of the secondary battery 100 of the present utility model, the end wall 112' includes a second through hole 1123, and the second through hole 1123 penetrates the end wall 112' in the thickness direction of the end wall 112'. The side of the second through-hole 1123 facing away from the electrode assembly 120 includes a first stepped hole 11231, the first stepped hole 11231 being disposed coaxially with the second through-hole 1123, the side of the first stepped hole 11231 facing away from the electrode assembly 120 including a first stepped surface 112311; the second current collecting member 152 'includes a second current collecting body 1524 and a connection portion 1522, the connection portion 1522 being disposed at a central region of the second current collecting body 1524, the connection portion 1522 extending toward the side of the end wall 112' in the height direction of the secondary battery 100. The connection portion 1522 is disposed in the second through hole 1123, and the first through hole 1521 penetrates through the center of the connection portion 1522; the connection portion 1522 includes a flange portion 1523 on a side facing away from the electrode assembly 120, the flange portion 1523 extends along a radial direction of the first through hole 1521 toward a side facing away from the axis of the secondary battery 100, the flange portion 1523 abuts against the first step surface 112311 on a side facing toward the electrode assembly 120 and is welded and fixed, and a second welding mark 15232 is formed on a side facing away from the electrode assembly 120 on the flange portion 1523, so as to achieve a welded connection between the second current collecting member 152 'and the end wall 112'. Referring to fig. 8 and 9, the secondary battery 100 further includes a cap plate 160 fixedly installed on the end wall 112', and the cap plate 160 covers the second through hole 1123; the specific shape of the cover plate 160 is not limited, and may be any shape such as square, round, or rectangular, and the second through hole 1123 may be sealed. So arranged, the cover plate 160 can cover the second through hole 1123 to prevent the electrolyte in the case 110' from leaking; and the second welding mark 15232 formed on the flange portion 1523 can be prevented from being oxidized and rusted by contact with the atmosphere, so that the stability of welding connection between the flange portion 1523 and the end wall 112' is improved. The cover plate 160 and the end wall 112' may be fixedly mounted in various manners, for example, may be welded and sealed, or may be fixedly bonded, so long as the second through hole 1123 can be sealed. By providing the flange portion 1523 on the second current collecting member 152 'and welding the flange portion 1523 with the first step surface 112311, on the one hand, when the second current collecting member 152' is welded with the end wall 112', the second current collecting member 152' is located above the end wall 112', and when laser penetration welding is performed from the side of the second current collecting member 152', the welding effect is better, the welding process window is larger, and the welding efficiency and the welding quality are improved; on the other hand, since the second through hole 1123 is provided in the end wall 112', and the second through hole 1123 communicates with the first through hole 1521 and the winding core through hole 121, the second through hole 1123 can be used as a filling hole, and no additional filling hole is required, so that the processing cost of the secondary battery 100 can be reduced.

Referring to fig. 8, in an example of the secondary battery 100 of the present utility model, the end cap 130 is provided with a liquid injection hole 1312, the liquid injection hole 1312 is in communication with the electrode assembly 120 inside the case 110', the specific position of the liquid injection hole 1312 on the end cap 130 is not limited, as long as the mounting area of the pole 140 is avoided, the liquid injection hole 1312 may be provided with one or a plurality of liquid injection holes, and in this embodiment, the liquid injection hole 1312 is provided with one. The explosion-proof valve 1313 is mounted on the liquid injection hole 1312 in a sealing manner, and various mounting modes of the explosion-proof valve 1313 on the liquid injection hole 1312 can be realized, for example, the explosion-proof valve 1313 can be connected to the liquid injection hole 1312 through threads, or can be connected to the liquid injection hole 1312 through sealant in an adhesive manner, and the like, so that the liquid injection hole 1312 can be sealed, and the normal use mounting mode of the explosion-proof valve 1313 is not influenced. By arranging the explosion-proof valve 1313 on the liquid injection hole 1312, the liquid injection hole 1312 integrates liquid injection and explosion-proof functions at the same time, and an additional mounting hole for the explosion-proof valve 1313 is not required to be arranged on the end cover 130, so that the processing procedure is simplified, and the production cost of the secondary battery 100 is reduced. The specific structure of the explosion-proof valve 1313 may be selected from various structures, for example, the structure may be an explosion-proof valve 1313 sheet, or an explosion-proof notch, so long as the explosion-proof valve 1313 can be opened in time to perform a pressure relief function when the internal pressure of the secondary battery 100 reaches a set value. In this embodiment, the explosion proof valve 1313 is in the form of an explosion proof valve 1313 piece. In the bending process, the flange 1523 has a large stress concentration phenomenon, so that a wrinkling phenomenon occurs, and the surface flatness of the flange 1523 is reduced. In order to improve the flatness of the surface of the flange portion 1523 and improve the quality of the welded connection of the flange portion 1523, referring to fig. 9, 12 and 13, in an example of the secondary battery 100 according to the present utility model, the flange portion 1523 includes at least one notch 15231 along the circumferential direction of the first through hole 1521. The shape and area of the cutout 15231 are not limited, and may be any shape such as square, fan, or triangle. The number and placement of the notches 15231 is not limited and can only function to release stress. In the present embodiment, the burring 1523 is symmetrically provided with two cutouts 15231 along the radial direction of the first through hole 1521, the shape of the cutout 15231 being approximately rectangular, the two cutouts 15231 dividing the burring 1523 into two parts. Through setting up incision 15231, when turn-ups portion bending, incision 15231 department can release a part shaping stress, reduces the stress concentration condition on the turn-ups portion 1523, reduces the wrinkling phenomenon on turn-ups portion 1523 surface, improves turn-ups portion 1523's surface smoothness, and then improves the stability of welding connection between turn-ups portion 1523 and the first step face 112311.

Referring to fig. 8 to 11, in an example of the secondary battery 100 of the present utility model, the second through hole 1123 further includes a second stepped hole 11232, the second stepped hole 11232 is located at a side of the first stepped hole 11231 facing away from the electrode assembly 120, the second stepped hole 11232 includes a second stepped surface 112321 at a side facing away from the electrode assembly 120, the second stepped surface 112321 is circumferentially disposed outside the first stepped surface 112311, and the cross-sectional shape of the second stepped hole 11232 is not limited, and may be square, rectangular, circular, or the like, for example, as long as the second stepped surface 112321 is circumferentially disposed outside the first stepped surface 112311; however, in the present embodiment, the second stepped hole 11232 and the first stepped hole 11231 are preferably coaxially arranged, so that positioning processing is convenient, and processing precision is easy to ensure. In the height direction of the secondary battery 100, the side of the cap plate 160 facing the electrode assembly 120 abuts against the second stepped surface 112321, and the height of the second stepped hole 11232 may not be limited, but preferably, in the present embodiment, the height of the second stepped hole 11232 coincides with the thickness of the cap plate 160. By providing the second stepped hole 11232, the thickness dimension of the cap plate 160 can be accommodated in the height direction, the height space of the secondary battery 100 occupied by the cap plate 160 can be reduced, and thus the volumetric energy density of the secondary battery 100 can be improved under the same height specification. Preferably, in another embodiment, the outer circumferential profile of the cover plate 160 is a circular structure matching the profile of the second stepped hole 11232, and the cover plate 160 is fitted in the second stepped hole 11232 in the circumferential direction. By this arrangement, the accuracy of the mounting and positioning of the cover plate 160 on the end wall 112' can be improved, and the sealing and connecting effects of the cover plate 160 can be ensured.

Referring to fig. 9, in an example of the secondary battery 100 of the present utility model, the height H of the first stepped hole 11231 is greater than or equal to the thickness of the burring 1523 in the height direction of the secondary battery 100. By the arrangement, the second welding marks 15232 on the flange portion 1523 can be prevented from abutting against the cover plate 160, the probability of damage in the installation process of the second welding marks 15232 is reduced, and the stability of welding connection between the flange portion 1523 and the end wall 112' is further ensured.

Referring to fig. 14, in an embodiment of a battery pack 200 of the present utility model, the battery pack 200 includes a case 210 and at least one secondary battery 100; the case 210 includes a first case portion 211 and a second case portion 212, the first case portion 211 and the second case portion 212 are covered with each other to form an accommodating space in which the plurality of secondary batteries 100 are accommodated, and the plurality of secondary batteries 100 may be connected in series and/or in parallel. The battery pack 200 may be a battery module, a battery pack, or the like.

Referring to fig. 15, in an example of the electronic device 300 of the present utility model, the electronic device 300 includes a working portion 310 and a battery pack 200, and the working portion 310 is electrically connected to the battery pack 200 to obtain power support. The working part 310 may be a unit part capable of taking the electric power of the battery pack 200 and making a corresponding work, such as a blade rotation unit of a fan, a dust suction working unit of a dust collector, a wheel driving unit in an electric vehicle, etc. The electronic device 300 may be a vehicle, a cellular phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. The vehicle can be a fuel oil vehicle, a fuel gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range-extended vehicle; spacecraft including airplanes, rockets, space planes, spacecraft, and the like; the electric toy includes fixed or mobile electric toys, such as a game machine, an electric car toy, an electric ship toy, and an electric airplane toy; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railroad power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete shakers, and electric planers, among others. The embodiment of the present utility model is not particularly limited to the above-described electronic device 300. In an embodiment of the electronic device of the present utility model, the electronic device 300 is a vehicle, the working portion 310 is a body of the vehicle, and the battery pack 200 is fixedly mounted on the body, so as to provide driving force for the vehicle, thereby realizing running of the vehicle.

In the secondary battery 100 provided by the utility model, the first through hole 1521 is provided on the second current collecting member 152, and the front projection of the first through hole 1521, the front projection of the winding core through hole 121 and the front projection of the second flat portion 1511 are overlapped at least in part, so that the welding fixture can be inserted into the first through hole 1521, and the second flat portion 1511 at the other end is subjected to torque welding, thereby completing the welded connection between the first current collecting member 151 and the pole 140 fixed on the end cap 130. In this structural arrangement, the first current collecting member 151 and the second current collecting member 152 may be welded to both ends of the electrode assembly 120, respectively, before the electrode assembly 120 is put into the case, and then the electrode post 140 and the first current collecting member 151 are torque-welded, thereby completing the fixed connection between the end cap 130 and the electrode assembly 120 at the outside of the case 110; the electrode assembly 120 is then assembled into the case 110 together with the cap 130 such that the cap 130 covers the opening 113 of the case 110, and finally the end wall 112 of the case 110 and the second current collecting member 152 are welded to each other at the outside of the case 110, and the cap 130 is welded to the side wall 111 of the case 110, thereby completing the assembly of the entire secondary battery 100. Unlike the conventional assembly process of the secondary battery 100, the secondary battery 100 in this embodiment omits the connection tab in the electrical connection link between the electrode post 140 and the electrode assembly 120, and does not require the folding operation of the connection tab, thereby reducing the number of parts, simplifying the assembly process, improving the assembly efficiency of the secondary battery 100, and reducing the production cost of the secondary battery 100. Therefore, the utility model effectively overcomes some practical problems in the prior art, thereby having high utilization value and use significance. The above embodiments are merely illustrative of the principles of the present utility model and its effectiveness, and are not intended to limit the utility model. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the utility model. Accordingly, it is intended that all equivalent modifications and variations of the utility model be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims (11)

1. A secondary battery, characterized by comprising:

A housing comprising an end wall and a side wall surrounding the end wall, the side wall being formed with an opening on a side facing away from the end wall;

an electrode assembly disposed within the case, a center of the electrode assembly including a winding core through hole;

An end cover arranged at the opening side and welded with the side wall to seal the opening;

A pole penetrating through the end cover and in insulating connection with the end cover, wherein one side of the pole positioned in the shell comprises a first flat part;

A first current collecting member disposed at a side of the electrode assembly facing the opening, the first current collecting member being electrically connected with the electrode assembly, the first current collecting member including a second flat portion corresponding to the first flat portion, and the second flat portion being welded with the first flat portion;

A second current collecting member at least partially disposed at a side of the electrode assembly facing the end wall, the second current collecting member being electrically connected with the electrode assembly and fixedly connected with the case;

And the second current collecting component is provided with a first through hole, and the orthographic projection of the first through hole, the orthographic projection of the winding core through hole and the orthographic projection of the pole connection area are at least partially overlapped along the height direction of the secondary battery.

2. The secondary battery according to claim 1, wherein the first current collecting member is of a flat sheet structure, and the second flat portion covers the core through hole.

3. The secondary battery according to claim 1, wherein the end wall includes a thinned region that is in contact with the second current collecting member and welded and fixed.

4. The secondary battery according to claim 3, wherein a first solder is provided on a wall of the thinned region facing away from the second current collecting member side, and the first solder is provided around the first through hole.

5. The secondary battery according to claim 1, wherein the end wall includes a second through hole, and a side of the second through hole facing away from the electrode assembly includes a first stepped hole; the second current collecting member comprises a connecting part, the connecting part is arranged in the second through hole in a penetrating way, one side of the connecting part, which is away from the electrode assembly, comprises a flanging part, and the flanging part is abutted against the step surface of the first step hole and is welded and fixed; the secondary battery further includes a cap plate covering the second through hole.

6. The secondary battery according to claim 1, wherein the end cap includes a liquid injection hole, and an explosion-proof valve is mounted on the liquid injection hole.

7. The secondary battery according to claim 5, wherein the burring includes at least one cutout in the circumferential direction of the first through hole.

8. The secondary battery according to claim 5, wherein the second through hole further comprises a second stepped hole at a side of the first stepped hole facing away from the electrode assembly, and the cap plate abuts against a stepped surface of the second stepped hole in a height direction of the secondary battery.

9. The secondary battery according to claim 5, wherein a height of the first stepped hole is greater than or equal to a thickness of the burring in a height direction of the secondary battery.

10. A battery pack comprising the secondary battery according to any one of claims 1 to 9.

11. An electronic device comprising the battery pack of claim 10.