Secondary battery, electronic device, and method for manufacturing secondary battery

Abstract

A secondary battery, an electronic device, and a method for manufacturing a secondary battery. The battery comprises a housing, an electrode assembly, a cover plate and a current collector member; one side of the housing is an opening side, and the other side opposite to said side of the housing is a closed side; the housing comprises a first cylinder and a second cylinder which are arranged in a segmented manner; one end of the first cylinder is provided with an end wall to form the closed side, and the other end of the first cylinder comprises a first connecting segment; one end of the second cylinder is provided with an opening to form the opening side, and the other end of the second cylinder comprises a second connecting segment; the second connecting segment is fixedly connected to the first connecting segment; a roll groove recessed inwards is formed in the second cylinder in a surrounding manner; the electrode assembly is accommodated in the housing; the cover plate is sealedly mounted at the opening; the current collector member is arranged between the electrode assembly and the cover plate and comprises a tab connecting portion and a housing connecting portion; the tab connecting portion is electrically connected to a tab; and the case connecting portion is electrically connected to the second cylinder. The battery structure can solve the technical problem of the falling of welding slag onto the housing during the welding of the current collector member to the housing.

Description

Secondary battery, electronic device, and method for manufacturing secondary battery Technical Field

[0001] The present disclosure relates to the field of batteries, and in particular to a secondary battery, an electronic device, and a method for manufacturing the secondary battery. Background Art

[0002] As one of the core components of new energy vehicles, lithium-ion batteries offer advantages such as high energy density, long cycle life, safety, and environmental friendliness, gradually becoming the mainstream trend in the electric vehicle era. Lithium-ion batteries are categorized by form factor: hard-shell, soft-pack, and cylindrical. Cylindrical batteries are particularly popular due to their high volumetric energy density, simple structure, ease of assembly, and ease of standardization.

[0003] The casing of a cylindrical battery is typically charged, allowing it to function as either the positive or negative electrode when assembled. The electrical connection between the electrode assembly within the casing and the casing is achieved by welding the electrode assembly to a current collecting member, which is then connected to the casing or cover plate, thereby achieving current conduction from the electrode assembly to the casing. The current collecting member is typically connected to the casing by welding, but foreign matter from welding that falls into the casing and affects electrical performance is a pressing issue.

[0004] Public content

[0005] In view of the above shortcomings of the prior art, the present disclosure provides a secondary battery, an electronic device and a method for manufacturing a secondary battery to improve the technical problem of welding slag falling on the shell during the welding process of the current collecting component and the shell when the secondary battery adopts a mechanical sealing process.

[0006] To achieve the above-mentioned objectives and other related objectives, the present disclosure provides a secondary battery, which comprises: a shell, an electrode assembly, a cover plate and a current collecting component; one side of the shell is an open side, and the other side opposite along the height direction of the secondary battery is a closed side, the shell comprises a first cylinder and a second cylinder segmented along the height direction of the secondary battery; one end of the first cylinder is provided with an end wall to form a closed side, and the other end of the first cylinder comprises a first connecting section; one end of the second cylinder is provided with an opening to form an open side, and the other end of the second cylinder comprises a second connecting section, the second connecting section is fixedly connected to the first connecting section, and a rolling groove recessed inwardly is provided around the main body of the second cylinder; the electrode assembly is accommodated in the shell and is arranged between the rolling groove and the end wall, the electrode assembly comprises a pole ear facing the opening; the cover plate is sealed and installed on the opening; the current collecting component is arranged between the electrode assembly and the cover plate, and comprises a pole ear connecting portion and a shell connecting portion, the pole ear connecting portion is electrically connected to the pole ear, and the shell connecting portion is electrically connected to the second cylinder.

[0007] In an example of the secondary battery disclosed herein, the first connecting segment and the second connecting segment at least partially overlap in a height direction of the secondary battery and form an overlapping area surrounding the housing.

[0008] In an example of the secondary battery disclosed herein, a length of the overlapping region along a height direction of the secondary battery is 0.1 to 5 mm.

[0009] In an example of the secondary battery disclosed herein, the second connecting segment shrinks toward the inside of the second cylinder and has a diameter smaller than that of the first connecting segment. The second connecting segment is inserted into the inside of the first connecting segment and cooperates with the inner wall of the first connecting segment to form an overlapping area.

[0010] In an example of the secondary battery disclosed herein, the second connecting segment contracts inwardly to form a first end surface, and the first end surface abuts against the first connecting segment and is fixed by welding.

[0011] In an example of the secondary battery disclosed herein, the second connecting segment protrudes outside the second cylinder and has a diameter larger than that of the first connecting segment. The first connecting segment is inserted into the inner side of the second connecting segment, and the second connecting segment cooperates with the outer wall of the first connecting segment to form an overlapping area.

[0012] In an example of the secondary battery disclosed herein, the second connecting segment is welded to the first connecting segment in the overlapping region.

[0013] In an example of the secondary battery disclosed herein, the first connecting segment shrinks toward the interior of the first cylinder and has a diameter smaller than that of the second connecting segment. The first connecting segment is inserted into the inner side of the second connecting segment and cooperates with the inner wall of the second connecting segment to form an overlapping area.

[0014] In an example of the secondary battery disclosed herein, the first connecting section shrinks inward to form a second end surface, and the second end surface abuts against the second connecting section and is fixed by welding.

[0015] In an example of the secondary battery disclosed herein, the first connecting segment protrudes outside the first cylinder and has a diameter larger than that of the second connecting segment. The second connecting segment is inserted into the inner side of the first connecting segment. The outer wall of the first connecting segment cooperates with the outer wall of the second connecting segment to form an overlapping area.

[0016] In an example of the secondary battery of the present disclosure, the first connecting segment and the second connecting segment are welded and connected in the overlapping area.

[0017] In an example of the secondary battery disclosed herein, in the height direction of the secondary battery, a circumferential surface of the electrode assembly corresponding to the welding position of the first connecting segment and the second connecting segment is provided with a high-temperature resistant protective layer.

[0018] In an example of the secondary battery disclosed herein, the second connecting segment is welded to the first connecting segment, and in the height direction of the secondary battery, the welding position of the second connecting segment and the first connecting segment corresponds to the height of the tab and / or the current collecting member.

[0019] In an example of the secondary battery disclosed herein, the rolling groove forms a bulge inside the second cylinder. Along the height direction of the secondary battery, the distance between the side of the bulge close to the electrode assembly and the end of the second cylinder away from the opening is L, and L≤15mm.

[0020] In an example of the secondary battery disclosed herein, the current collecting member includes a central hole, the tab connection portion is disposed around the central hole, and the housing connection portion is disposed around the tab connection portion.

[0021] In an example of the secondary battery disclosed herein, the shell connection portion and the tab connection portion are an integral annular flat sheet, the tab connection portions are welded to the tabs, and the shell connection portion is welded to the side of the protrusion facing the electrode assembly.

[0022] In an example of the secondary battery disclosed herein, the shell connection portion is welded to the side of the protrusion facing away from the electrode assembly, and the tab connection portion is recessed toward the electrode assembly relative to the shell connection portion and is welded to the tab.

[0023] In an example of the secondary battery disclosed herein, a side of the second barrel facing away from the electrode assembly includes a flange extending toward the center of the opening, and an edge of the cover is sealed and pressed between the flange and the protrusion.

[0024] In an example of the secondary battery disclosed herein, a groove is formed between the flange and the protrusion, and a sealing member is provided between the cover plate and the groove.

[0025] In an example of the secondary battery disclosed herein, the sealing member surrounds and wraps around the edge of the cover plate, and the flange presses the sealing member and the cover plate.

[0026] In an example of the secondary battery of the present disclosure, a drain portion is provided on the cover plate.

[0027] In an example of the secondary battery of the present disclosure, the discharge portion includes a notch provided on the cover plate, and an opening of the notch is close to the electrode assembly.

[0028] In an example of the secondary battery disclosed herein, the cover plate includes a plurality of reinforcing ribs, which are radially distributed around the axis of the cover plate and extend radially along the cover plate.

[0029] In an example of the secondary battery disclosed herein, the first cylinder and the second cylinder are both made of metal.

[0030] The present disclosure also provides an electronic device including a battery pack including a secondary battery.

[0031] In addition, the method of manufacturing a secondary battery according to one or more embodiments of the present disclosure may include the following steps:

[0032] Installing the electrode assembly into the first barrel;

[0033] Welding the current collecting member and the second cylinder to form an integrated component;

[0034] Butt the integrated component to one end of the first cylinder, and weld the second cylinder of the integrated component to the first cylinder;

[0035] welding the current collecting member to the tab of the electrode assembly facing the current collecting member; and

[0036] The cover plate is sealed and mounted on the opening of the second cylinder facing away from the first cylinder.

[0037] In a method for manufacturing a secondary battery according to one or more embodiments disclosed herein: the second cylinder includes a rolling groove recessed toward the interior of the second cylinder, the rolling groove forming a bulge inside the second cylinder; the current collecting member is welded to a side of the bulge close to the electrode assembly to form an integrated component.

[0038] In a method for manufacturing a secondary battery according to one or more embodiments disclosed in the present disclosure: an integrated component is nested with one end of a first cylinder to form an overlapping area; the second cylinder is fixedly connected to the first cylinder by irradiating a laser in the overlapping area, the electrode assembly is inserted into a cavity formed by the first cylinder and the integrated component, and the current collecting member is in contact with the electrode assembly.

[0039] In the method for manufacturing a secondary battery according to one or more embodiments of the present disclosure, an electrolyte is injected into the opening before the step of sealingly mounting the cap plate on the opening of the second cylindrical body.

[0040] The secondary battery disclosed in the present invention has a shell comprising a first cylinder and a second cylinder segmented along the height direction; an end wall is provided at one end of the first cylinder to form a closed side, and the other end of the first cylinder comprises a first connecting section; an opening is provided at one end of the second cylinder to form an open side, and the other end of the second cylinder comprises a second connecting section, the second connecting section is fixedly connected to the first connecting section, and a rolling groove recessed inward is provided around the main body of the second cylinder; the current collecting component is provided between the electrode assembly and the cover plate, and comprises a tab connecting portion and a shell connecting portion, the tab connecting portion is electrically connected to the tab, and the shell connecting portion is electrically connected to the second cylinder; the rolling groove is provided in the second cylinder, and a mechanical sealing process with mature technology, low cost and high efficiency can be used.

[0041] The separate design of the second cylinder and the first cylinder allows the welding process of the current collecting member and the second cylinder to be carried out at a location far away from the first cylinder and the electrode assembly. First, it can prevent welding slag from falling into the interior of the secondary battery. In addition, when the current collecting member and the second cylinder are welded, there is no obstruction at both ends of the second cylinder, so welding can be carried out directly inside the second cylinder. Moreover, the laser can be irradiated from one side of the current collecting member, penetrating the relatively thin current collecting member to the second cylinder, resulting in a large welding process window and high welding efficiency.

[0042] The manufacturing method disclosed in the present invention first welds the current collecting component and the second cylinder to form an integrated component. The current collecting component and the second cylinder are pre-welded before the secondary battery is assembled, thereby avoiding the risk of welding slag falling into the interior of the secondary battery, increasing the welding process window between the current collecting component and the shell, and reducing production costs. Finally, the cover plate is sealed and installed on the opening of the second cylinder through a mechanical sealing process. While retaining the mature, low-cost and high-efficiency mechanical sealing process, the process difficulties in the welding process of the current collecting component and the shell in the prior art are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying any creative work.

[0044] FIG1 is a schematic diagram of the overall structure of an embodiment of a secondary battery disclosed herein;

[0045] FIG2 is a partial enlarged view of an example at point A in FIG1 ;

[0046] FIG3 is a partial enlarged view of point B in FIG2 ;

[0047] FIG4 is a partial enlarged view of another example of point A in FIG1 ;

[0048] FIG5 is a partial enlarged view of point C in FIG4 ;

[0049] FIG6 is a partial enlarged view of another example of point A in FIG1 ;

[0050] FIG7 is a partial enlarged view of point D in FIG6;

[0051] FIG8 is a partial enlarged view of another example of point A in FIG1 ;

[0052] FIG9 is a partial enlarged view of point E in FIG8 ;

[0053] FIG10 is a partial enlarged view of an example at point A in FIG1 ;

[0054] FIG11 is a partial enlarged view of point F in FIG10 ;

[0055] FIG12 is a partial enlarged view of an example at point A in FIG1 ;

[0056] FIG13 is a partial enlarged view of point G in FIG12;

[0057] FIG14 is a schematic structural diagram of integrated components of an embodiment of a secondary battery disclosed herein;

[0058] FIG15 is a partial cross-sectional view of a first barrel of a secondary battery according to an embodiment of the present disclosure;

[0059] FIG16 is a schematic diagram of an electronic device according to an embodiment of the present disclosure;

[0060] FIG17 is a schematic structural diagram of a battery pack according to an embodiment of the electronic device disclosed herein;

[0061] FIG18 is a flow chart of an embodiment of a method for manufacturing a secondary battery disclosed herein.

[0062] Component number description 1. electronic device; 10. battery pack; 11. working part; 101. box body; 102. box cover; 100. secondary battery; 110. shell; 111. first cylinder; 1111. end wall; 1112. first connecting section; 1113. second end face; 112. second cylinder; 1121. rolling groove; 1122. protrusion; 1123. opening; 1124. groove; 1125. flange; 1126. second connecting section; 1127. first end face; 113. first necking portion; 1131. first weld mark; 114. first flaring portion; 1141. second weld mark; 115. second necking portion; 1151. third weld mark; 116. second flaring portion; 1161. fourth weld mark Mark; 117, overlapping area; 120, electrode assembly; 121, second electrode ear; 122, first electrode ear; 123, high temperature resistant protective layer; 130, first current collecting component; 131, electrode ear connection; 132, shell connection; 1321, fifth weld mark; 1322, sixth weld mark; 133, center hole; 140, second current collecting component; 150, pole; 160, cover plate; 161, discharge part; 162, notch; 163, reinforcement rib; 164, first side; 165, second side; 166, third side; 170, seal; 180, integrated component. DETAILED DESCRIPTION

[0063] The following describes the embodiments of the present disclosure through specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that the following examples and the features in the examples can be combined with each other unless there is a conflict. It should also be understood that the terms used in the examples of the present disclosure are for the purpose of describing specific embodiments, not for the purpose of limiting the scope of protection of the present disclosure. The test methods for which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under the conditions recommended by the manufacturers.

[0064] When numerical ranges are given in the examples, it should be understood that unless otherwise specified in this disclosure, both endpoints of each numerical range and any value between the two endpoints can be used. Unless otherwise defined, all technical and scientific terms used in this disclosure are consistent with the prior art knowledge of those skilled in the art and the description of this disclosure. Any prior art methods, equipment, and materials similar or equivalent to those in the examples of this disclosure can also be used to implement this disclosure.

[0065] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present disclosure. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present disclosure without substantially changing the technical content.

[0066] Referring to Figures 1 to 18, the present disclosure provides a secondary battery 100, an electronic device 1, and a method for manufacturing the secondary battery 100. In the secondary battery 100, the housing 110 includes a first barrel 111 and a second barrel 112 that are segmented along the height direction of the secondary battery 100; the height direction of the secondary battery 100 is shown in the direction indicated by Z in Figure 1. One end of the first barrel 111 is provided with an end wall 1111 to form a closed side, and the other end of the first barrel 111 includes a first connecting section 1112; one end of the second barrel 112 is provided with an opening 1123 to form an open side, and the second barrel 112 is provided with an opening 1123 to form an open side. The other end of the body 112 includes a second connecting section 1126, which is fixedly connected to the first connecting section 1112. A rolling groove 1121 that is recessed inward is arranged around the main body of the second cylinder 112; the first current collecting component 130 is arranged between the electrode assembly 120 and the cover plate 160, and includes a tab connecting portion 131 and a shell connecting portion 132, and the shell connecting portion 132 is electrically connected to the second cylinder 112; the technical problem of the process difficulty in welding the first current collecting component 130 and the shell 110 when the secondary battery 100 adopts a mechanical sealing process is improved.

[0067] 1 , a secondary battery 100 of the present disclosure includes a housing 110 , an electrode assembly 120 , a terminal post 150 , current collecting members 130 and 140 , and a cap plate 160 .

[0068] One side of the shell 110 is an open side, and the other side opposite to the height direction of the secondary battery 100 is a closed side. The shell 110 includes a first barrel 111 and a second barrel 112 which are segmented along the height direction of the secondary battery 100; the first barrel 111 and the second barrel 112 can be cylindrical or prismatic, or can be barrels surrounded by any other closed-loop contour. The first barrel 111 and the second barrel 112 can have the same shape or different shapes. As an embodiment, in this embodiment, the first barrel 111 and the second barrel 112 are both cylindrical, and an end wall 1111 is provided at one end of the first barrel 111. The shape of the end wall 1111 can be various, and it is preferred to be consistent with the shape surrounded by the first barrel 111.

[0069] Please refer to Figures 1 to 3. One end of the first barrel 111 is provided with an end wall 1111 to form a closed side, and the other end of the first barrel 111 includes a first connecting section 1112; one end of the second barrel 112 is provided with an opening 1123 to form an open side, and the other end of the second barrel 112 includes a second connecting section 1126. The second connecting section 1126 is fixedly connected to the first connecting section 1112 to achieve a fixed connection between the other end of the first barrel 111 and the second barrel 112; the fixed connection method includes, but is not limited to, a threaded connection, a tenon connection, a welding connection, an adhesive connection, etc. The housing 110 of the secondary battery 100 needs to be charged, so the first barrel 111 and the second barrel 112 are fixedly connected. The material is metal, such as copper, iron, aluminum, steel, aluminum alloy, etc. The materials of the first barrel 111 and the second barrel 112 can be the same or different. Considering that the sealing requirements of the shell 110 of the secondary battery 100 are relatively high, in this embodiment, the first barrel 111 and the second barrel 112 are fixed by welding. As long as the sealing connection between the first barrel 111 and the second barrel 112 can be achieved, the welding position and weld mark shape of the first barrel 111 and the second barrel 112 are not limited. In addition, in order to prevent the shell 110 from rusting during long-term use, a layer of rust-proof material such as metal nickel can be plated on the surface of the shell 110 after the first barrel 111 and the second barrel 112 are welded and fixed. The first cylinder 111 and the shell 110 surrounded by the first cylinder 111 form a accommodating cavity for accommodating the electrode assembly 120, electrolyte (not shown) and other necessary battery components. The diameters of the first cylinder 111 and the second cylinder 112 can be determined according to the specific size of the electrode assembly 120, such as 18 mm, 21 mm, 46 mm, etc.

[0070] Referring to Figures 1 to 14, an opening 1123 is provided at one end of the second barrel 112 to form an open side. Since mechanical sealing has the advantages of mature technology and equipment and fast production cycle, a mechanical sealing process is adopted for sealing. Specifically, a rolling groove 1121 is provided around the main body of the second barrel 112 and is recessed into the interior of the second barrel 112. The rolling groove 1121 forms a protrusion 1122 inside the second barrel 112. In an example of the secondary battery 100 of the present disclosure, the edge of the cover plate 160 is placed until the protrusion 1122 faces the opening 112. 3, and then, a sealing process is used to flange the side wall of the open end of the second cylinder 112 toward the center of the opening 1123, forming a groove 1124 between the flange 1125 and the protrusion 1122, and the edge of the cover plate 160 is sealed and press-fitted between the flange 1125 and the protrusion 1122, and is located in the groove 1124. Specifically, the surface of the cover plate 160 that cooperates with the groove 1124 includes a first side surface 164 close to the protrusion 1122, a second side surface 165 close to the bottom of the groove 1124, and a third side surface 166 close to the flange 1125. There are many ways to seal the cover plate 160, such as filling a sealant between the edge of the cover plate 160 and the groove 1124, applying a sealing coating on the edge of the cover plate 160, or providing a seal 170 between the cover plate 160 and the groove 1124. Preferably, in this embodiment, a seal 170 is provided between the cover plate 160 and the groove 1124. The material of the seal 170 can be rubber, metal, graphite or polytetrafluoroethylene, etc., and the cross-sectional shape can be an O-ring, an L-shaped seal, etc. In this embodiment, the seal 170 is made of rubber and has a shape that surrounds and wraps the edge of the cover plate 160. Specifically, the seal is in the form of wrapping the first side 164, the second side 165 and the third side 166 of the cover plate 160, as shown in Figure 7. In addition, since the high temperature generated by welding when sealing can cause the electrolyte inside the secondary battery 100 to decompose, the use of mechanical sealing can improve the problem of electrolyte decomposition.

[0071] Referring to Figures 1 and 2, the electrode assembly 120 is housed within the housing 110 and disposed between the rolling groove 1121 and the end wall 1111. The protrusion 1122 formed by the rolling groove 1121 can limit the axial displacement of the electrode assembly 120. The electrode assembly 120 is the component where the electrochemical reaction occurs in the secondary battery 100. The housing 110 may contain one or more electrode assemblies 120. The electrode assembly 120 is primarily formed by winding or stacking positive and negative electrode sheets, and a separator is typically provided between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material. The positive active material is coated on the surface of the positive current collector. The positive current collector includes a coated area coated with the active material and an uncoated area not coated with the active material. The uncoated area, after winding, forms the positive electrode tab of the electrode assembly 120. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material. The negative electrode active material is coated on the surface of the negative electrode current collector. The negative electrode current collector includes a coated area coated with the active material and an uncoated area not coated with the active material. The uncoated area, when wound, forms the negative electrode tab of the electrode assembly 120. Taking the lithium-ion secondary battery 100 as an example, the positive electrode current collector can be made of aluminum, and the positive electrode active material includes a positive electrode active material. The positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode current collector can be made of copper, and the negative electrode active material includes a negative electrode active material. The negative electrode active material can be carbon or silicon. The separator can be made of materials such as PP (polypropylene) or PE (polyethylene). To protect and insulate the battery cell, an insulating film can be applied to the outside of the cell. The insulating film can be made of PP, PE, PET, PVC, or other polymer materials.

[0072] Please refer to FIG1 . The electrode assembly 120 in the present disclosure includes two tabs 121 and 122 facing the end wall 1111 and the opening 1123. For the convenience of distinction, the tab facing the opening 1123 is named the first tab 122, and the tab facing the end wall 1111 is named the second tab 121. The second tab 121 can be a positive tab or a negative tab. The electrical properties of the first tab 122 and the second tab 121 are opposite. When the second tab 121 is a positive tab, the first tab 122 is a negative tab. When the second tab 121 is a positive tab, the first tab 122 is a negative tab. When tab 121 is the negative electrode tab, first tab 122 is the positive electrode tab. Both tabs are connected to current collecting members 130 and 140. For ease of distinction, the one connected to first tab 122 is designated as first current collecting member 130, and the one connected to second tab 121 is designated as second current collecting member 140. Second tab 121 is electrically connected to terminal post 150 via second current collecting member 140. First current collecting member 130 is disposed at the end of electrode assembly 120 facing opening 1123 and is welded to first tab 122. In this embodiment, second tab 121 is the positive electrode tab, and terminal post 150 is electrically connected to second tab 121, resulting in a positive charge. First tab 122 is the negative electrode tab, and the side of housing 110 opposite opening 1123 from end wall 1111 is electrically connected to first tab 122, resulting in a negative charge.

[0073] Referring to FIG1 , a pole 150 is mounted on the end wall 1111 of the first cylinder 111. The pole 150 passes through the end wall 1111 and is insulated from the end wall 1111. The pole 150 can be structured in any suitable form that can pass through the end wall 1111 to electrically connect to the second tab 121 of the electrode assembly 120. For example, the cross-section can be circular, square, prismatic, or have a special-shaped profile that can achieve stable electrical conductivity. In this embodiment, a mounting hole for the pole 150 is provided on the end wall 1111, and the pole 150 is sealed and insulated and installed in the mounting hole for the pole 150. This housing 110 structure can improve installation efficiency, and its assembly and sealing properties are superior to those of a housing 110 with openings 1123 at both ends. The end of the electrode post 150 facing the electrode assembly 120 passes through the end wall 1111 and is electrically connected to the second electrode tab 121 directly or indirectly via a transfer connection. In this embodiment, the electrode post 150 is electrically connected to the second electrode tab 121 via a transfer connection through the second current collecting member 140. The end of the electrode post 150 facing the opening 1123 is welded to the second current collecting member 140, and the side of the second current collecting member 140 facing away from the electrode post 150 is welded to the second electrode tab 121. The end of the electrode post 150 facing away from the electrode assembly 120 is exposed to the outside of the housing 110 to form a connection surface for connection to an external busbar.

[0074] Please refer to Figures 1 to 2. The first current collecting member 130 is arranged between the electrode assembly 120 and the cover plate 160. The structure of the first current collecting member 130 is not limited. For example, it can be all structures that are electrically connected to the electrode assembly 120 and the shell 110. The first current collecting member 130 includes a tab connection portion 131 and a shell connection portion 132. The tab connection portion 131 is electrically connected to the first tab 122 on the side close to the electrode assembly 120. The electrical connection method can be a direct fixed connection or an adapter. In this embodiment, the electrical connection method between the tab connection portion 131 and the first tab 122 is a welding connection, including but not limited to laser welding. The shell connection portion 132 is electrically connected to the second barrel. The shell connecting portion 132 and the second cylinder 112 are electrically connected, and the electrical connection method can be a direct fixed connection or an electrical connection through an adapter. In this embodiment, the shell connecting portion 132 and the second cylinder 112 are connected by welding, including but not limited to laser welding. The position of the connection between the shell connecting portion 132 and the second cylinder 112 is not limited. It can be a circumferential welding connection between the shell connecting portion 132 and the inner wall of the second cylinder 112, or it can be a welding connection between the shell connecting portion 132 and the protrusion 1122. As long as a reliable connection between the shell connecting portion 132 and the second cylinder 112 can be achieved, in this embodiment, the shell connecting portion 132 and the protrusion 1122 are welded together. This method has a large welding process window and is firm.

[0075] 1 to 3 and 14 , in the secondary battery 100 of the present disclosure, the second barrel 112 and the first barrel 111 are designed to be separated, so that the welding process of the first current collecting member 130 and the second barrel 112 can be carried out at a location away from the first barrel 111 and the electrode assembly 120. First, this can prevent welding slag from falling into the interior of the secondary battery 100. In addition, when the first current collecting member 130 and the second barrel 112 are welded, the cover plate 160 has not yet been installed. Therefore, there is no obstruction at both ends of the second barrel 112, and welding can be performed directly inside the second barrel 112. Moreover, the laser can be irradiated from one side of the first current collecting member 130, penetrating the relatively thin first current collecting member 130 to the second barrel 112, resulting in a large welding process window and high welding efficiency. While retaining the mature, low-cost and high-efficiency mechanical sealing process, the process difficulties in the welding process of the first current collecting member 130 and the shell 110 in the prior art are improved.

[0076] Please refer to FIG7. Considering the reliability of the fixed connection between the first barrel 111 and the second barrel 112, in an example of the secondary battery 100 disclosed in the present invention, the first connecting section 1112 and the second connecting section 1126 at least partially overlap in the height direction of the secondary battery 100 and form an overlapping area 117 surrounding the shell 110. When the first barrel 111 and the second barrel 112 are threadedly connected, the overlapping area 117 is used to construct the thread. When the first barrel 111 and the second barrel 112 are tenon-connected, the overlapping area 117 is used to construct the mortise and tenon. When the first barrel 111 and the second barrel 112 are tenon-connected, the overlapping area 117 is used to construct the mortise and tenon. When the body 112 is welded, the overlapping area 117 is used for positioning and pre-fixing before welding to make welding easier to operate, and can provide conditions for penetrating welding on the other hand. It can also be used to block the laser during welding to reduce the high temperature generated during welding that damages the electrode assembly 120. The overlapping area 117 can be formed by inserting the first connecting segment 1112 of the first cylinder 111 into the second connecting segment 1126 of the second cylinder 112, or by inserting the second connecting segment 1126 of the second cylinder 112 into the first connecting segment 1112 of the first cylinder 111.

[0077] Preferably, in an example of the secondary battery 100 disclosed in the present invention, the length of the overlapping area 117 along the height direction of the secondary battery 100 is represented by S, please refer to Figure 7, the range of S is 0.1 to 5 mm, and the specific length of S can be selected accordingly according to the specific connection method of the first cylinder 111 and the second cylinder 112. When the first cylinder 111 and the second cylinder 112 are welded together, the setting of this range is conducive to the stability of the welding between the first cylinder 111 and the second cylinder 112, and can reduce the thermal impact of the welding heat on the electrode assembly 120.

[0078] 2 to 3 and 7 , in an example of the secondary battery 100 of the present disclosure, the second connecting section 1126 shrinks toward the inside of the second barrel 112 and has a diameter smaller than that of the first connecting section 1112 . The second connecting section 1126 is inserted into the inner side of the first connecting section 1112 and cooperates with the inner wall of the first connecting section 1112 to form an overlapping area 117 . In order to distinguish it from other embodiments, the second connecting section 1126 here is named the first necking portion 113 . The setting of the first necking portion 113 , on the one hand, serves as a guide when the second barrel 112 is installed on the first barrel 111 , and on the other hand, it can block the laser during welding to reduce damage to the electrode assembly 120 caused by high temperature. On the other hand, the first necking portion 113 shrinks toward the inside of the second barrel 112 , so that the outer walls of the first barrel 111 and the second barrel 112 are aligned and flat, which facilitates that a single battery cell occupies a smaller module space when multiple batteries are connected in series and parallel.

[0079] Preferably, in this embodiment, the second connecting section 1126, namely the first necked portion 113, shrinks inwardly and forms a first end face 1127, please refer to Figure 14, the first end face 1127 abuts against the first connecting section 1112 and is fixed by welding, and is welded on the contact surface between the end face of the first connecting section 1112 and the first end face 1127 to form a first weld mark 1131 as shown in Figure 3, and is welded by seam welding, which is low in cost, high in efficiency, and firm and reliable in welding; it should be noted that the first necked portion 113 and the inner wall of the first connecting section 1112 are preferably an interference fit, which is beneficial to improving the sealing performance and positioning function of the welding between the first cylinder 111 and the second cylinder 112, and at the same time is beneficial to reducing the possibility of welding slag generated during welding falling into the interior of the secondary battery 100.

[0080] Please refer to Figures 4 to 5 and Figure 7. In another example of the secondary battery 100 disclosed in the present invention, the second connecting segment 1126 protrudes toward the outside of the second cylinder 112 and has a diameter greater than that of the first connecting segment 1112. The first connecting segment 1112 is inserted into the inner side of the second connecting segment 1126. The second connecting segment 1126 cooperates with the outer wall of the first connecting segment 1112 to form an overlapping area 117. In order to distinguish it from other embodiments, the second connecting segment 1126 here is named the first flared portion 114. The setting of the first flared portion 114, on the one hand, serves as a guide when the second cylinder 112 is installed on the first cylinder 111. On the other hand, the first flared portion 114 protrudes toward the outside of the second cylinder 112, which can reduce the risk of the second cylinder 112 scratching the electrode assembly 120 when the second cylinder 112 is installed on the first cylinder 111.

[0081] Preferably, in this embodiment, the second connecting section 1126, that is, the first flared portion 114, is welded to the first connecting section 1112 in the overlapping area 117. The welding of the first flared portion 114 and the first connecting section 1112 can be performed by seam welding or penetration welding. In this embodiment, seam welding is used. Specifically, a second weld mark 1141 surrounding the first connecting section 1112 is formed on the contact surface between the inner wall of the first flared portion 114 and the outer wall of the first connecting section 1112. Please refer to Figure 5. The seam welding method is low in cost, high in efficiency, and the welding is firm and reliable. At the same time, the welding slag formed by this welding method will not have the risk of falling into the interior of the secondary battery 100. In addition, the direction of laser irradiation is along the height direction of the secondary battery 100, which reduces the damage to the electrode assembly 120 caused by the high temperature generated by the laser.

[0082] Referring to Figures 6 and 7, in another example of the secondary battery 100 of the present disclosure, the first connecting section 1112 shrinks toward the inside of the first barrel 111 and has a diameter smaller than that of the second connecting section 1126. The first connecting section 1112 is inserted into the inner side of the second connecting section 1126 and cooperates with the inner wall of the second connecting section 1126 to form an overlapping area 117. In order to distinguish it from other embodiments, the first connecting section 1112 here is named the second necking portion 115. The setting of the second necking portion 115 is, on the one hand, for the second barrel 112 to be installed on the first barrel 111 when it is installed. On the other hand, the second necked portion 115 is arranged on the first cylinder 111, which can reduce the risk of the second cylinder 112 scratching the electrode assembly 120 when the second cylinder 112 is installed on the first cylinder 111. The second necked portion 115 can also block the laser during welding to reduce the damage to the electrode assembly 120 caused by high temperature. In addition, the second necked portion 115 shrinks toward the first cylinder 111, so that the outer walls of the first cylinder 111 and the second cylinder 112 are aligned and flat, which is convenient for a single battery cell to occupy a smaller module space when multiple batteries are connected in series and parallel.

[0083] Preferably, in this embodiment, the first connecting section 1112, namely the second necked portion 115, shrinks inwardly and forms a second end face 1113, please refer to Figure 15, the second end face 1113 abuts against the second connecting section 1126 and is fixed by welding, and is welded on the contact surface between the end face of the second connecting section 1126 and the second end face 1113 to form a third weld mark 1151 as shown in Figure 7, and is welded by seam welding, which has low cost, high efficiency and firm and reliable welding; it should be noted that it is better that the second necked portion 115 and the inner wall of the second connecting section 1126 are fitted with an interference fit, which is beneficial to improving the sealing performance and positioning function of the welding between the first cylinder 111 and the second cylinder 112, and at the same time is beneficial to reducing the possibility of welding slag generated during welding falling into the interior of the secondary battery 100.

[0084] Please refer to Figures 7 to 9. In another example of the secondary battery 100 disclosed in the present invention, the first connecting section 1112 protrudes toward the outside of the first barrel 111 and has a diameter greater than that of the second connecting section 1126. The second connecting section 1126 is inserted into the inner side of the first connecting section 1112. The outer wall of the first connecting section 1112 and the second connecting section 1126 cooperate to form an overlapping area 117. In order to distinguish it from other embodiments, the first connecting section 1112 here is named the second flared portion 116. The setting of the second flared portion 116, on the one hand, serves as a guide when the second barrel 112 is installed on the first barrel 111. On the other hand, the second flared portion 116 protrudes toward the outside of the first barrel 111, which can reduce the risk of the second barrel 112 scratching the electrode assembly 120 when the second barrel 112 is installed on the first barrel 111.

[0085] Preferably, in the embodiment, the first connecting section 1112, i.e., the second flared portion 116, and the second connecting section 1126 are welded together in the overlapping area 117. The welding of the second flared portion 116 and the second connecting section 1126 can be performed by seam welding or penetration welding. In this embodiment, seam welding is used. Specifically, a fourth weld mark 1161 surrounding the second connecting section 1126 is formed on the contact surface between the inner wall of the second flared portion 116 and the outer wall of the second connecting section 1126. Please refer to Figure 9. The seam welding method is low in cost, high in efficiency, and the welding is firm and reliable. At the same time, the welding slag formed by this welding method will not have the risk of falling into the interior of the secondary battery 100. In addition, the direction of laser irradiation is along the height direction of the secondary battery 100, which reduces the damage to the electrode assembly 120 caused by the high temperature generated by the laser.

[0086] Please refer to Figure 3. Considering that the high temperature generated during welding of the first connecting segment 1112 and the second connecting segment 1126 may damage the electrode assembly 120, in an example of the secondary battery 100 disclosed in the present invention, a high-temperature resistant protective layer 123 is provided on the circumferential surface of the electrode assembly 120 corresponding to the welding position of the first connecting segment 1112 and the second connecting segment 1126. The high-temperature resistant protective layer 123 can be in various forms, such as wrapping a high-temperature resistant tape around the circumference of the electrode assembly 120, or coating it with a high-temperature resistant coating.

[0087] Please refer to Figures 10 and 11. In an example of the secondary battery 100 disclosed in the present invention, the second connecting segment 1126 is welded to the first connecting segment 1112. In the height direction of the secondary battery 100, the welding position of the second connecting segment 1126 and the first connecting segment 1112 corresponds to the height of the first electrode tab 122 and / or the first current collecting member 130, so that the high temperature generated during welding of the second connecting segment 1126 and the first connecting segment 1112 will not affect the coating area of ​​the electrode assembly 120. It should be noted that the matching method and welding form of the second connecting segment 1126 and the first connecting segment 1112 in this embodiment can adopt any of the methods shown in Figures 2 to 9. It should be noted that the shapes of all the weld marks in Figures 2 to 9 above are only for reference and are not used to limit the shape of the weld marks.

[0088] Please refer to Figures 3, 5, 7 and 9. In an example of the secondary battery 100 disclosed in the present invention, along the height direction of the secondary battery 100, the distance between the second cylinder 112 and the side of the protrusion 1122 close to the electrode assembly 120 to the end of the second cylinder 112 away from the outlet 1123 is L, and L≤15mm. The setting of L not exceeding 15mm ensures that the first cylinder 111 has sufficient length to accommodate the electrode assembly 120 and provides a stable constraint to the electrode assembly 120 to prevent the electrode assembly 120 from falling out. When the second cylinder 112 is installed on the first cylinder 111, the risk of the second cylinder 112 scratching the electrode assembly 120 is reduced. At the same time, it makes it more convenient to operate the second cylinder 112 when welding with the first current collecting member 130.

[0089] In the prior art, when a mechanical sealing process is used, the first current collecting member 130 is welded to the shell 110 by first welding the shell connecting portion 132 of the first current collecting member 130 to the inner wall of the shell 110, and then rolling the shell connecting portion 132 and the shell 110 together into a groove 1121, and pressing the shell connecting portion 132 between the rolling groove 1121 and the electrode assembly 120. This process is prone to breaking the shell connecting portion 132, or causing the first current collecting member 130 to warp due to the bending of the shell connecting portion 132, thereby causing the welding of the tab connecting portion 131 and the first tab 122 to be damaged. The first current collecting member 130 is designed and manufactured according to the welding process. In an example of the secondary battery 100 of the present disclosure, please refer to Figures 2 to 14. The first current collecting member 130 includes a center hole 133, a tab connection portion 131 is arranged around the center hole 133, and a shell connection portion 132 is arranged around the tab connection portion 131. The present disclosure reduces the requirements for the structure of the first current collecting member 130, simplifies the structure of the first current collecting member 130, reduces production costs, and improves production efficiency.

[0090] Please refer to Figures 2 to 11. In an example of the secondary battery 100 of the present disclosure, the shell connecting portion 132 and the tab connecting portion 131 are an integral annular flat sheet, the tab connecting portion 131 is welded to the tab, and the first current collecting member 130 is set as an annular flat sheet, which reduces production costs, reduces the difficulty of processing and assembly, and improves production efficiency. Preferably, the shell connecting portion 132 is welded to the side of the protrusion 1122 close to the electrode assembly 120, and a fifth weld mark 1321 is formed on the side of the shell connecting portion 132 close to the electrode assembly 120. As shown in Figure 3, since the thickness of the first current collecting member 130 is larger than that of the protrusion 1122, the first current collecting member 130 is larger than that of the protrusion 1122. The wall thickness of the second cylinder 112 is thin, so laser is used to irradiate from one side of the first current collecting member 130 to penetrate the relatively thin first current collecting member 130 to the second cylinder 112. The welding process window is large and the welding efficiency is high. In addition, structurally, the shell connection portion 132 is located between the electrode assembly 120 and the protrusion 1122. When the second cylinder 112 is installed on the first cylinder 111, the pressure exerted by the electrode assembly 120 on the first current collecting member 130 is conducive to pressing the first current collecting member 130 and the first electrode tab 122 tightly, thereby facilitating welding between the first current collecting member 130 and the first electrode tab 122.

[0091] Please refer to Figures 12 to 14. In another example of the secondary battery 100 of the present disclosure, the shell connection portion 132 is welded to the side of the protrusion 1122 away from the electrode assembly 120, and a sixth weld mark 1322 is formed on the side of the shell connection portion 132 away from the electrode assembly 120. As shown in Figure 13, since the thickness of the first current collecting member 130 is thinner than the wall thickness of the second cylinder 112, a laser is used to irradiate from one side of the first current collecting member 130 to penetrate the relatively thin first current collecting member 130 to the second cylinder 112, resulting in a large welding process window and high welding efficiency. The tab connection portion 131 is recessed toward the electrode assembly 120 relative to the shell connection portion 132 and is welded to the first tab 122. Structurally, the shell connection portion 132 is located on the side of the protrusion 1122 away from the electrode assembly 120, which means that the shell connection portion 132 is pressed together by the flange 1125 during mechanical sealing, thereby improving the stability of the connection between the shell connection portion 132 and the protrusion 1122. In addition, the cover plate 160 and the shell connection portion 132 may or may not be in contact, without limitation. In one embodiment, the cover plate 160 is in contact with the shell connection portion 132, and the pressure applied to the shell connection portion 132 by the flange 1125 through the cover plate 160 is conducive to pressing the pole tab connection portion 131 and the first pole tab 122 tightly, thereby facilitating welding between the first current collecting component 130 and the first pole tab 122.

[0092] Referring to Figures 2, 4, 6, 8, 10, and 12, in one example of the secondary battery 100 of the present disclosure, a vent 161 is provided on the cover plate 160. The vent 161 is configured to at least partially open when the internal pressure of the housing 110 reaches a certain level, thereby releasing the pressure within the housing 110. The type of explosion-proof structure is not limited, and for example, it can be an explosion-proof valve assembly mounted on the cover plate 160.

[0093] Referring to Figures 2, 4, 6, 8, 10, and 12, in an example of the secondary battery 100 disclosed herein, the discharge portion 161 includes a notch 162 provided on the cover plate 160, and the notch 162 is an annular structure. It should be noted that the annular structure does not limit the notch 162 to be circular or elliptical. In the present disclosure, the notch 162 can be considered to be an annular structure if it is connected end to end. Of course, in other embodiments, the notch 162 may not be connected end to end, for example, it may be a non-annular profile such as a C-shape or a cross-shape, so as to be able to open when the pressure exceeds a set threshold. In this way, the position of the notch 162 is an area where the strength of the cover plate 160 is relatively weak. When the air pressure inside the shell 110 exceeds a certain threshold (the strength of the notch 162 can be calculated to achieve at least partial opening when the air pressure exceeds a certain threshold), the air pressure inside the shell 110 is discharged from the rupture, thereby preventing the secondary battery 100 from exploding from the shell 110 and causing thermal runaway at the module level. Considering that the notch 162 will damage the nickel-plated layer on the surface of the cover plate 160, and thus rust is likely to occur at the position of the notch 162, it is preferred that the opening 1123 of the notch 162 is set on the side of the cover plate 160 facing the electrode assembly 120, so that the notch 162 is located in the enclosed space within the shell 110, reducing the contact between the notch 162 and the air, which can slow down the degree of rust of the notch 162 and improve the service life of the notch 162.

[0094] Please refer to Figures 2, 4, 6, 8, 10 and 12. In an example of the secondary battery 100 disclosed in the present invention, the cover plate 160 includes a plurality of reinforcing ribs 163. The plurality of reinforcing ribs 163 are radially distributed with the axis of the cover plate 160 as the center and extend radially along the cover plate 160. In this embodiment, there are eight reinforcing ribs 163, which are evenly distributed circumferentially on the cover plate 160. The reinforcing ribs 163 are configured as integrally formed protrusions 1122. The protrusions 1122 are formed on the side of the cover plate 160 away from the electrode assembly 120. This configuration improves the strength of the cover plate 160 without increasing material costs or increasing the weight of the cover plate 160.

[0095] Please refer to Figure 16. The present disclosure also provides an electronic device 1, which includes a battery pack 10, and a working part 11 is electrically connected to the battery pack 10 to obtain power support. As an example, the electronic device 1 is a vehicle. The vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc., but is not limited to this. The working part 11 is the vehicle body, and the battery pack 10 is arranged at the bottom of the vehicle body and provides power support for the driving of the vehicle or the operation of electrical components in the vehicle. However, in some other embodiments, the electronic device 1 can also be a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy and an electric tool, etc. Spacecraft include airplanes, rockets, space shuttles and spacecraft, etc. The working part 11 can be a unit component that can obtain power from the battery pack 10 and perform corresponding work, such as a fan blade rotation unit, a vacuum cleaner dust collection unit, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys; electric tools include metal cutting tools, grinding tools, assembly tools, and railway tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. The present embodiment does not impose any particular restrictions on the electronic device 1.

[0096] Referring to Figure 17 , the battery pack 10 includes any of the aforementioned secondary batteries 100. In one embodiment of the battery pack 10 disclosed herein, the battery pack 10 includes a housing 101, a housing cover 102, and a plurality of secondary batteries 100. The plurality of secondary batteries 100 are placed within the housing 101 and connected in series or in parallel, or in a combination of these. The housing cover 102 seals the housing 101 to protect the plurality of secondary batteries 100. It should be noted that, in addition to the secondary batteries 100 disclosed herein, the battery pack 10 may also include a thermal management system, a circuit board, and other components. The battery pack 10 may be a battery module, a battery pack, an energy storage cabinet, or the like; detailed descriptions thereof will not be provided herein.

[0097] In addition, referring to FIG. 18 , the method for manufacturing the secondary battery 100 according to one or more embodiments of the present disclosure may include the following steps:

[0098] Please refer to FIG. 1 , the electrode assembly 120 is installed to the first cylinder 111 ; this step can be performed by referring to the installation method of the electrode assembly 120 to the shell 110 in the prior art, and will not be described in detail here.

[0099] Please refer to Figures 1 to 14. The first current collecting member 130 is welded to the second cylinder 112 to form an integrated component 180, please refer to Figure 14; specifically, a rolling groove 1121 that is recessed toward the interior of the second cylinder 112 is first processed on the second cylinder 112, and the rolling groove 1121 forms a protrusion 1122 inside the second cylinder 112. Then, the first current collecting member 130 is welded to the protrusion 1122. The welding can be performed on the side of the protrusion 1122 away from the electrode assembly 120, as shown in Figures 12 to 13, or welded on the side of the protrusion 1122 close to the electrode assembly 120, as shown in Figures 2 to 11, to form the integrated component 180, please refer to Figure 14. This step completes the pre-welding of the first current collecting member 130 to the second barrel 112, fundamentally changing the welding method for the first current collecting member 130 to the housing 110. This eliminates the risk of welding slag falling into the interior of the secondary battery 100 and eliminates the technical difficulties associated with welding the first current collecting member 130 to the housing 110 in the prior art. Precise positioning of the first current collecting member 130 is also eliminated, reducing the number of positioning steps, widening the welding process window for the first current collecting member 130 to the housing 110, and reducing production costs. It should be noted that this step is not precedence or sequenced with the installation of the electrode assembly 120 to the first barrel 111, and neither step affects the other.

[0100] Please refer to Figures 2 to 11, the integrated component 180 is docked with one end of the first cylinder 111, and the second cylinder 112 of the integrated component 180 is welded and fixed to the first cylinder 111; specifically, the integrated component 180 and one end of the first cylinder 111 are nested to form an overlapping area 117, please refer to Figure 7, the second cylinder 112 is fixedly connected to the first cylinder 111 by irradiating laser in the overlapping area 117, the electrode assembly 120 is sleeved in the cavity formed by the first cylinder 111 and the integrated component 180, and the first current collecting component 130 is abutted against the electrode assembly 120. It should be noted that the second cylinder 112 and the first cylinder 111 can be welded and fixed using any of the matching and welding methods in the above-mentioned embodiments, please refer to Figures 2 to 11.

[0101] Referring to Figures 1 to 2, the first current collecting member 130 and the first electrode tab 122 of the electrode assembly 120 facing the opening 1123 are welded from within the opening 1123; specifically, the second cylinder 112 includes a rolling groove 1121 that is recessed into the interior of the second cylinder 112, and the rolling groove 1121 forms a protrusion 1122 inside the second cylinder 112; the first current collecting member 130 is welded to the side of the protrusion 1122 close to the electrode assembly 120 to form an integrated component 180. In the prior art, the first current collecting component 130 and the first pole tab 122 are first welded and then grooved 1121 is rolled. This is because the bending of the connection portion of the shell 110 of the first current collecting component 130 causes the inside of the first current collecting component 130 to warp, which in turn causes the weld between the pole tab connection portion 131 and the first pole tab 122 to break, resulting in the risk of electrical connection failure of the electrode assembly 120. In this embodiment, in this step, the welding of the first current collecting component 130 and the first pole tab 122 is performed after the groove 1121 is rolled on the second cylinder 112. The change in process sequence can reduce the possibility of fracture at the weld between the pole tab connection portion 131 and the first pole tab 122.

[0102] Please refer to Figures 2 to 13 to see that the cover plate 160 is sealed and installed on the opening 1123 of the second cylinder 112 away from the first cylinder 111. There are multiple packaging methods. Preferably, a mechanical sealing process is used for packaging. Specifically, the edge of the cover plate 160 is placed on the side of the protrusion 1122 facing the opening 1123. Then, a sealing process is used to bend the side wall of the open end of the second cylinder 112 toward the center of the opening 1123, forming a groove 1124 between the flange 1125 and the protrusion 1122. The edge of the cover plate 160 is sealed and pressed between the flange 1125 and the protrusion 1122. This step is a mature process with low cost and high efficiency. In addition, since the high temperature generated by welding when sealing can cause the electrolyte inside the secondary battery 100 to decompose, the use of a mechanical sealing method can improve the problem of electrolyte decomposition.

[0103] Furthermore, the manufacturing method also includes injecting electrolyte. The method of injecting the electrolyte is not limited. It can be injected into the opening 1123 or an injection hole can be set on the end wall 1111 for injection. Preferably, in this embodiment, the electrolyte is injected into the opening 1123, which reduces the process of opening the injection hole on the end wall 1111 and can be directly injected through the existing opening 1123, which simplifies the process and reduces the cost.

[0104] It should be noted that FIG18 is only a flow chart of one embodiment of the manufacturing method. The order of the steps in the method can be adaptively adjusted according to actual conditions and is not limited by FIG18.

[0105] The secondary battery disclosed herein has a housing having an open side on one side and a closed side on the other side opposite in the height direction of the secondary battery. The housing includes a first barrel and a second barrel segmented in the height direction. One end of the second barrel is provided with an opening to form the open side. The other end of the second barrel includes a second connecting section fixedly connected to the first connecting section. A rolling groove recessed inwardly is provided around the main body of the second barrel. The first current collecting member is provided between the electrode assembly and the cover plate and includes a tab connecting portion and a housing connecting portion electrically connected to the second barrel. The separate design of the second barrel and the first barrel allows the welding process of the first current collecting member and the second barrel to be performed away from the first barrel and the electrode assembly, thereby preventing welding slag from falling into the interior of the secondary battery. In addition, when welding the first current collecting member and the second barrel, there is no obstruction at both ends of the second barrel, allowing welding to be performed directly inside the second barrel. Laser light can be irradiated from one side of the first current collecting member, penetrating the relatively thin first current collecting member to the second barrel, resulting in a wide welding process window and high welding efficiency. The control method disclosed herein first welds the first current collecting member and the second barrel to form an integrated component. This pre-welding method, prior to secondary battery assembly, avoids the risk of welding slag falling into the secondary battery interior, increases the welding process window between the first current collecting member and the housing, and reduces production costs. Finally, the cover plate is sealed over the opening of the second barrel using a mechanical sealing process. While retaining the proven, low-cost, and high-efficiency mechanical sealing process, it also alleviates the technical difficulties associated with welding the first current collecting member and the housing in the prior art. Therefore, the present disclosure effectively overcomes several practical issues in the prior art and thus has high utility and practical significance. The above embodiments are merely illustrative of the principles and effectiveness of the present disclosure and are not intended to limit the present disclosure. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present disclosure. Therefore, all equivalent modifications or alterations made by persons of ordinary skill in the art without departing from the spirit and technical principles of the present disclosure are intended to be covered by the claims of the present disclosure.

Claims

1. A secondary battery, It is characterized in that include: A shell, one side of the shell is an open side, and the other side opposite to the secondary battery in the height direction is a closed side, and the shell includes a first cylinder and a second cylinder that are arranged in sections in the height direction of the secondary battery; One end of the first cylinder is provided with an end wall to form the closed side, and the other end of the first cylinder includes a first connecting section; One end of the second cylinder is provided with an opening to form the open side, the other end of the second cylinder comprises a second connecting section, the second connecting section is fixedly connected to the first connecting section, and a rolling groove concave inwardly is arranged around the main body of the second cylinder; an electrode assembly, contained in the housing and disposed between the rolling groove and the end wall, the electrode assembly comprising a pole ear facing the opening; A cover plate, sealingly mounted on the opening; The current collecting member is disposed between the electrode assembly and the cover plate, and comprises a tab connection portion and a shell connection portion, wherein the tab connection portion is electrically connected to the tab, and the shell connection portion is electrically connected to the second cylinder.

2. The secondary battery according to claim 1, It is characterized in that The first connecting section and the second connecting section at least partially overlap in a height direction of the secondary battery and form an overlapping area surrounding the housing.

3. The secondary battery according to claim 2, It is characterized in that The length of the overlapping area along the height direction of the secondary battery is 0.1 to 5 mm.

4. The secondary battery according to claim 2, It is characterized in that The second connecting section shrinks toward the inside of the second cylinder and has a diameter smaller than that of the first connecting section. The second connecting section is inserted into the inner side of the first connecting section and cooperates with the inner wall of the first connecting section to form the overlapping area.

5. The secondary battery according to claim 4, It is characterized in that The second connecting section shrinks inwardly to form a first end surface, and the first end surface abuts against the first connecting section and is fixed by welding.

6. The secondary battery according to claim 2, It is characterized in that The second connecting section protrudes outward from the second cylinder and has a diameter greater than that of the first connecting section. The first connecting section is inserted into the inner side of the second connecting section. The second connecting section cooperates with the outer wall of the first connecting section to form the overlapping area.

7. The secondary battery according to claim 6, It is characterized in that The second connecting section is welded to the first connecting section in the overlapping area.

8. The secondary battery according to claim 2, It is characterized in that The first connecting section shrinks toward the inside of the first cylinder and has a diameter smaller than that of the second connecting section. The first connecting section is inserted into the inner side of the second connecting section and cooperates with the inner wall of the second connecting section to form the overlapping area.

9. The secondary battery according to claim 8, It is characterized in that The first connecting section shrinks inwardly to form a second end surface, and the second end surface abuts against the second connecting section and is fixed by welding.

10. The secondary battery according to claim 2, It is characterized in that The first connecting section protrudes outward from the first cylinder and has a diameter greater than that of the second connecting section. The second connecting section is inserted into the inner side of the first connecting section. The first connecting section cooperates with the outer wall of the second connecting section to form the overlapping area.

11. The secondary battery according to claim 10, It is characterized in that The first connecting section and the second connecting section are connected by welding in the overlapping area.

12. The secondary battery according to any one of claims 5, 7, 9 and 11, It is characterized in that In the height direction of the secondary battery, a high temperature resistant protective layer is provided on the peripheral surface of the electrode assembly corresponding to the welding position of the first connecting segment and the second connecting segment.

13. The secondary battery according to claim 1, It is characterized in that The second connecting segment is welded to the first connecting segment, and in the height direction of the secondary battery, a welding position of the second connecting segment and the first connecting segment corresponds to a height of the electrode tab and / or the current collecting member.

14. The secondary battery according to claim 1, It is characterized in that The rolling groove forms a bulge inside the second cylinder, and along the height direction of the secondary battery, the distance from the side of the bulge close to the electrode assembly to the end of the second cylinder away from the opening is L, and L≤15mm.

15. The secondary battery according to claim 14, It is characterized in that The current collecting component includes a central hole, the tab connection portion is disposed around the central hole, and the housing connection portion is disposed around the tab connection portion.

16. The secondary battery according to claim 15, It is characterized in that The shell connection part and the pole tab connection part are an integral annular flat sheet, the pole tab connection part is welded to the pole tab, and the shell connection part is welded to a side of the protrusion facing the electrode assembly.

17. The secondary battery according to claim 15, It is characterized in that The shell connection portion is welded to a side of the protrusion facing away from the electrode assembly, and the tab connection portion is recessed toward the electrode assembly relative to the shell connection portion and is welded to the tab.

18. The secondary battery according to claim 14, It is characterized in that The side of the second cylinder away from the electrode assembly includes a flange extending toward the center of the opening, and the edge of the cover plate is sealed and pressed between the flange and the protrusion.

19. The secondary battery according to claim 18, It is characterized in that A groove is formed between the flange and the protrusion, and a sealing member is arranged between the cover plate and the groove.

20. The secondary battery according to claim 19, It is characterized in that The sealing member surrounds and wraps the edge of the cover plate, and the flange presses the sealing member and the cover plate.

21. The secondary battery according to claim 1, It is characterized in that The cover plate is provided with a discharge portion.

22. The secondary battery according to claim 21, It is characterized in that The discharge portion includes a notch disposed on the cover plate, and an opening of the notch is close to the electrode assembly.

23. The secondary battery according to claim 1, It is characterized in that The cover plate includes a plurality of reinforcing ribs, which are radially distributed around the axis of the cover plate and extend radially along the cover plate.

24. The secondary battery according to claim 1, It is characterized in that The first cylinder and the second cylinder are both made of metal.

25. An electronic device, It is characterized in that A battery pack is provided, the battery pack comprising the secondary battery according to any one of claims 1 to 24.

26. A method for manufacturing a secondary battery, It is characterized in that The method comprises the following steps: Installing the electrode assembly into the first cylinder; Welding the current collecting member and the second cylinder to form an integrated component; Butt the integrated component with one end of the first cylinder, and weld and fix the second cylinder of the integrated component with the first cylinder; welding the current collecting member and the electrode tab of the electrode assembly facing the current collecting member; and The cover plate is sealingly mounted on the opening of the second cylinder which is away from the first cylinder.

27. The method for manufacturing a secondary battery according to claim 26, It is characterized in that The second cylinder includes a rolling groove recessed toward the inside of the second cylinder, and the rolling groove forms a bulge inside the second cylinder; The current collecting member is welded to a side of the protrusion close to the electrode assembly to form the integrated component.

28. The method for manufacturing a secondary battery according to claim 27, It is characterized in that The integrated component is nested with one end of the first cylinder to form an overlapping area; The second barrel is fixedly connected to the first barrel by irradiating laser in the overlapping area, the electrode assembly is sleeved in the cavity formed by the first barrel and the integrated component, and the current collecting member is in contact with the electrode assembly.

29. The method for manufacturing a secondary battery according to claim 27, It is characterized in that Before the step of sealingly mounting the cover plate on the opening of the second cylinder, an electrolyte is injected into the opening.

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