Cylindrical battery, electronic device, and manufacturing method for cylindrical battery

Abstract

To provide a cylindrical battery, an electronic device, and a manufacturing method for a cylindrical battery.SOLUTION: A cylindrical battery includes a housing, an electrode assembly, and a current collecting member. The housing includes a side wall, and an opening is formed at one end of the side wall. At a position close to the opening of the side wall, a roll groove that is depressed into the housing is included. The electrode assembly is provided inside the housing, and the roll groove restricts the displacement of the electrode assembly to an axial direction of the housing. At least a part of the current collecting member is provided between the electrode assembly and the roll groove. The current collecting member includes a current collecting main body and a connection piece connected to a periphery of the current collecting main body. The current collecting main body is electrically connected to the electrode assembly. The connection piece is bent toward the axial line of the housing and welded to a surface of the roll groove facing the electrode assembly, thereby forming a welded part. Between the side wall and a part between the welded part of the connection piece and the periphery of the current collecting main body, a gap exists.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to the technical field of batteries, and more particularly to cylindrical batteries, electronic devices, and methods for manufacturing cylindrical batteries. [Background technology]

[0002] In existing cylindrical batteries, a current collecting member is typically provided near the opening of the housing, with one end of the current collecting member welded to the side wall of the housing and the other end electrically connected to a tab on the electrode assembly, thereby achieving electrical connection between the housing and the electrode assembly. However, in subsequent assembly processes, the housing must undergo additional processes such as roll grooving and sealing at the opening, which makes the welding position between the current collecting member and the housing prone to damage, leading to poor electrical connection between the electrode assembly and the housing and reducing the yield of cylindrical batteries. Summary of the Invention [Problem to be solved by the invention]

[0003] In view of the above-mentioned drawbacks of the existing technology, the present invention provides a cylindrical battery, an electronic device, and a method for manufacturing a cylindrical battery, which improve the problem that poor electrical connection is likely to occur between the electrode assembly and the housing during the production process of the cylindrical battery. [Means for solving the problem]

[0004] To achieve the above and other related objects, the present invention provides a cylindrical battery. The cylindrical battery includes a housing, an electrode assembly, and a current collecting member. The housing includes a sidewall, with an opening formed at one end of the sidewall. The sidewall includes a roll groove recessed into the housing near the opening. The electrode assembly is disposed within the housing, and the roll groove limits displacement of the electrode assembly in the axial direction of the housing. The current collecting member is disposed at least partially between the electrode assembly and the roll groove. The current collecting member includes a current collecting body and a connecting piece connected to the periphery of the current collecting body. The current collecting body is electrically connected to the electrode assembly. The connecting piece is bent toward the axis of the housing and welded to the surface of the roll groove facing the electrode assembly to form a weld. A gap exists between the sidewall and a portion between the weld of the connecting piece and the periphery of the current collecting body.

[0005] In one example of the cylindrical battery of the present invention, there is no contact between the side wall and the portion between the welded portion of the connection piece and the current collecting body.

[0006] In one example of the cylindrical battery of the present invention, the entire portion along the circumferential direction of the side wall between the welded portion of the connection piece and the current collecting body does not contact the side wall.

[0007] In one example of the cylindrical battery of the present invention, the current collecting member includes a plurality of connection pieces, and the plurality of connection pieces are provided so as to surround the outer edge of the current collecting body.

[0008] In one example of the cylindrical battery of the present invention, the connection piece includes a first connection portion and a second connection portion that connect to each other, the first connection portion is located between the welded portion and the current collecting body, and the second connection portion extends from one end of the first connection portion close to the welded portion into the interior of the housing, where the first connection portion is bent relative to the second connection portion to form a first bent portion.

[0009] In one example of the cylindrical battery of the present invention, the thickness of the connection piece is 0.1 to 0.3 mm.

[0010] In one example of the cylindrical battery of the present invention, the first bent portion extends along the circumferential direction of the side wall, and the first bent portion is provided with a first fragile structure.

[0011] In one example of the cylindrical battery of the present invention, the first frangible structure includes a thinned region provided at the first bend.

[0012] In one example of the cylindrical battery of the present invention, the first frangible structure includes an openwork region provided in the first bent portion.

[0013] In one example of the cylindrical battery of the present invention, the first connection portion is bent toward the center of the current collecting body to form a second bent portion.

[0014] In one example of the cylindrical battery of the present invention, the second bent portion is provided with a second frangible structure.

[0015] In one example of the cylindrical battery of the present invention, the developed length from one end of the connecting piece connected to the current collecting body to the free end of the connecting piece is A, the minimum distance between the second bend portion and the side wall is Δ, the length of the second connecting portion is F, and the width size of the welded portion along the extension direction of the second connecting portion is W, and 0.2 mm + W≦F≦(0.05 mm×A) / Δ.

[0016] In one example of the cylindrical battery of the present invention, the length of the second connecting portion is F, and the width size of the welded portion along the extension direction of the second connecting portion is W, and 0.2 mm + W≦F≦0.05 mm / sin4.

[0017] In one example of the cylindrical battery of the present invention, the roll groove includes a first groove wall facing the electrode assembly, the weld includes a molten pool, and in an axial cross-section of the cylindrical battery, the side of the contour line of the molten pool away from the axis of the housing intersects with the first groove wall to form a first intersection point, and an obtuse angle θ away from the axis of the housing is formed between the tangent line of the contour line passing through the first intersection point and the first groove wall.

[0018] In one example of the cylindrical battery of the present invention, at least a portion of the central region of the current collector body protrudes along the axial direction of the housing toward the opening and is higher than the peripheral region of the current collector body that is covered by the roll grooves.

[0019] The present invention further provides an electronic device, the electronic device including a battery assembly, the battery assembly including a cylindrical battery according to any one of the above examples.

[0020] The present invention further provides a method for manufacturing a cylindrical battery. The cylindrical battery includes a housing, an electrode assembly, a current collecting member, and an end cap. The housing includes a side wall, and an opening is formed at one end of the side wall. The current collecting member includes a current collecting body and a connecting piece fixedly connected to the periphery of the current collecting body. The manufacturing method includes the following steps: welding a current collecting body of the current collecting member to a tab of the electrode assembly to form a cell assembly; installing the cell assembly into the housing through the opening; The connecting piece is extended toward the opening side and overlapped at an angle on the side wall of the housing, thereby forming a welding-ready area between the connecting piece and the side wall, and a gap exists between the side wall and a portion between the welding-ready area of ​​the connecting piece and the current collecting body; welding the weld-ready region to form a weld between the connection piece and the side wall; Roll pressing a region of the side wall corresponding to the weld to form a roll groove, and allowing the roll groove to limit axial displacement of the electrode assembly; Install end caps to seal the openings.

[0021] In one example of the manufacturing method of the present invention, before welding the welding-waiting area, the inclination angle between the connection piece and the housing is β, and the angle range of β is 1° to 4°.

[0022] In one example of the manufacturing method of the present invention, before welding the area to be welded, the size from the contact end of the connecting piece with the side wall to the connection end of the connecting piece with the current collecting body along the extension direction of the connecting piece is A, and 2 mm≦A≦4 mm.

[0023] In one example of the manufacturing method of the present invention, the distance from the region to be welded to the end wall of the connecting piece along the extending direction of the connecting piece is 0.2 mm or more.

[0024] In one example of the manufacturing method of the present invention, the distance between the connection piece and the side wall in the region to be welded along the radial direction of the housing is 0.05 mm or less.

[0025] In one example of the manufacturing method of the present invention, laser welding is used to weld the area waiting to be welded, and the laser beam generated by the welding head is emitted from inside the housing to the area waiting to be welded, and the welding operation is performed in a position that is inclined relative to the side wall.

[0026] In one example of the manufacturing method of the present invention, the range of the tilt angle γ between the laser beam generated by the welding head and the side wall is 15° to 80°. [Effects of the Invention]

[0027] In the cylindrical battery of the present invention, the welds are formed by welding the connection pieces provided on the outer periphery of the current collecting member to the surface of the roll groove facing the electrode assembly, allowing the welds to be distributed around the circumferential direction of the housing. This reduces stress concentration between the current collecting member and the housing and contributes to a stable connection between the current collecting member and the housing. At the same time, the portion between the welded portion of the connection piece and the current collecting member does not come into contact with the side wall. In this way, the portion between the welded portion of the connection piece and the current collecting member is not subjected to extrusion pressure from the corresponding side wall during roll grooving. This reduces the possibility of the connection piece being displaced relative to the wall of the roll groove at the welded portion, effectively improving the stability of the weld between the connection piece and the roll groove. This improves the stability of the electrical connection between the electrode assembly and the housing, increases the yield of cylindrical batteries, and ensures the usability of cylindrical batteries.

[0028] The method for manufacturing a cylindrical battery of the present invention forms an inclined overlap between the connection piece and the side wall after the cell assembly, formed by welding the current collecting member to the electrode assembly, is installed in the housing. This not only facilitates the insertion of the cell assembly into the housing and improves insertion efficiency, but also ensures that the portion of the connection piece between the pre-weld area and the current collecting body does not come into contact with the side wall. This configuration reduces the possibility that the portion of the connection piece between the welded portion and the current collecting body will come into contact with the side wall after the housing is roll-grooved, preventing the side wall from applying additional extrusion pressure to the connection piece located at the welded portion. This reduces the possibility that the connection piece will be displaced relative to the roll groove at the welded portion, ultimately improving the stability of the electrical connection between the connection piece and the housing and improving the yield of cylindrical batteries. [Brief explanation of the drawings]

[0029] In order to more clearly describe the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. The drawings described below are only some embodiments of the present invention, and it is obvious that those skilled in the art can obtain other embodiments based on these drawings without expending creative efforts. [Figure 1] 1 is a cross-sectional view of the overall structure of one embodiment of a cylindrical battery of the present invention. [Figure 2] FIG. 2 is a partial enlarged view of an area A in FIG. [Figure 3] FIG. 1 is a structural diagram of the position of the weld after roll grooving in one embodiment of the cylindrical battery of the present invention. [Figure 4] FIG. 2 is a structural diagram of a cylindrical battery according to an embodiment of the present invention after the connecting pieces have been bent. [Figure 5] FIG. 5 is a partial enlarged view of an area B in FIG. 4. [Figure 6] FIG. 5 is a structural diagram of the embodiment of FIG. 4 before the connecting piece is bent. [Figure 7] FIG. 7 is a cross-sectional view of the current collecting member of the embodiment of FIG. 6. [Figure 8] FIG. 8 is a partial enlarged view of an area C in FIG. 7. [Figure 9] 1 is a structural view of a cylindrical battery according to an embodiment of the present invention before the connecting pieces are bent. [Figure 10] FIG. 10 is a cross-sectional view of the current collecting member of the embodiment of FIG. 9. [Figure 11] FIG. 11 is a partial enlarged view of an area D in FIG. [Figure 12] FIG. 10 is a diagram showing another embodiment of a cylindrical battery of the present invention, in which a frangible structure is provided at both the first bent portion and the second bent portion. [Figure 13] FIG. 2 is a partial enlarged view of a weld after roll grooving of one embodiment of the cylindrical battery of the present invention. [Figure 14] FIG. 2 is a structural diagram of the open side of one embodiment of a cylindrical battery of the present invention before roll grooving. [Figure 15] 1 is a diagram of a welding position between a welding head and a connecting piece of one embodiment of a cylindrical battery of the present invention. FIG. [Figure 16] 1 is a diagram of the position between the molten pool and the side wall and connecting piece in one embodiment of the cylindrical battery of the present invention. FIG. [Figure 17] FIG. 10 is a partial view of the overlap position between the connecting piece and the side wall before roll grooving in one embodiment of the cylindrical battery of the present invention. [Figure 18] FIG. 10 is a diagram showing the distribution positions of the weld-waiting areas between the connecting pieces and the side walls before roll grooving in one embodiment of the cylindrical battery of the present invention. [Figure 19] FIG. 1 is a diagram of the welding position between the welding head and the side wall before roll grooving of one embodiment of the cylindrical battery of the present invention. [Figure 20] 1 is an overall structural diagram of one embodiment of a battery assembly of the present invention. [Figure 21] 1 is a structural diagram of a battery assembly according to the present invention mounted on a vehicle; [Figure 22] FIG. 1 is a flow diagram of one embodiment of a method for manufacturing a cylindrical battery of the present invention. [Figure 23]2# is a diagram showing the destruction effect when the connection piece on the current collecting member is peeled off from the welded part b. [Figure 24] 3# This is a diagram of the destruction effect when the connection piece on the current collecting member is peeled off from the welded part c. [Figure 25] 4# is a diagram showing the destruction effect when the connection piece on the current collecting member is peeled off from the welded part d. [Figure 26] 10A and 10B are diagrams showing a peel test of the weld formed between the connecting piece of the present invention and the side wall. DETAILED DESCRIPTION OF THE INVENTION

[0030] The following describes how the present invention is implemented through specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention may be implemented or applied in other different specific embodiments. Various changes and modifications may be made to the details of this specification based on different perspectives and applications without departing from the spirit of the present invention. The following embodiments and their features may be combined with each other unless inconsistent. It should also be understood that the terms used in the embodiments of the present invention do not limit the scope of protection of the present invention but are intended to describe specific embodiments. Test methods without specifying specific conditions in the following embodiments are usually based on general conditions or conditions recommended by manufacturers.

[0031] When an embodiment provides a numerical range, it should be understood that the two endpoints of each numerical range and any numerical value between the two endpoints can be selected unless otherwise specified in the present invention. Unless otherwise defined, all technical and scientific terms used in the present invention are consistent with the understanding of the prior art by those skilled in the art and the description of the present invention. The present invention can also be achieved by combining any method, equipment, or procedure in the prior art that is similar or equivalent to the method, equipment, or material described in the embodiments of the present invention.

[0032] The terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are used for the convenience of explanation and do not limit the scope of the present invention. Changing or adjusting the relative relationships between these terms is also considered to be within the scope of the present invention, provided that the technical content is not substantially changed.

[0033] 1 to 26, the present invention provides a cylindrical battery 100. When roll grooving 113 is performed at the position of the opening 112 in the housing 110, the cylindrical battery 100 reduces the possibility that the weld 140 formed by the connection piece 132 and the roll groove 113 will be displaced during the roll grooving process, effectively increasing the stability of the welding between the connection piece 132 and the roll groove 113, thereby increasing the stability of the electrical connection between the electrode assembly 120 and the housing 110 and improving the yield and usability of the cylindrical battery 100.

[0034] The structure of the cylindrical battery 100 will be further described with reference to FIGS. 1 and 2. The cylindrical battery 100 includes a housing 110, an electrode assembly 120, and a current collecting member 130. A receiving cavity is formed within the housing 110 to accommodate the electrode assembly 120, electrolyte, and other components. The housing 110 may be open at one end or both ends. The specific size of the housing 110 may be determined based on the specific size of the electrode assembly 120, and may conform to cylindrical battery standards such as 4680, 4695, and 46120. The housing 110 may be made of a variety of materials, such as copper, iron, aluminum, steel, and aluminum alloy. To prevent the housing 110 from rusting during long-term use, the surface of the housing 110 may be plated with a layer of anti-corrosion material, such as metallic nickel.

[0035] 1 to 3, in one example of a cylindrical battery 100 of the present invention, a housing 110 has a cylindrical structure and includes an end wall 114 and a side wall 111 surrounding the end wall 114. That is, the housing 110 includes a sealed end and an open end. The end wall 114 is the sealed end, and an opening 112 facing the end wall 114 is the open end. A roll groove 113 recessed into the housing 110 is formed on the side of the side wall 111 facing the opening 112. A main body portion 115 is formed in the side wall 111 between the roll groove 112 and the end wall 114, and the main body portion 115 extends along the height direction of the cylindrical battery 100. A transition portion 116 is formed in the side wall 111 between the roll groove 113 and one end of the end wall 114 remote from the main body portion 115. The roll groove 113 is an indentation structure formed by the side wall 111 being pushed toward the inside of the housing 110 and deformed by the action of a mechanical external force. The roll groove 113 may be formed by pressing the side wall 111 using a molding die, or by performing roll pressing on the side wall 111 using a roll grooving cutting tool. Any indentation structure may be formed in the side wall 111, forming the roll groove 113 in a ring shape in the circumferential direction of the side wall 111. The cross-sectional shape of the roll groove 113 may be any shape that meets usage requirements, such as a rectangle, a square, or a trapezoid. The side wall 111 further includes an extension portion 117 extending toward the center of the opening 112 on the side of the roll groove 113 closer to the opening 112, and a connection portion 118 is further provided between the extension portion 117 and the roll groove 113. The extension portion 117 and the roll groove 113 are connected via the connection portion 118. It should be noted that the specific sizes of the roll groove 113, the extension portion 117, and the connection portion 118 are determined based on the size standard of the cylindrical battery 100. This is not a limitation in this embodiment. The side of the roll groove 113 away from the opening 112 has a first groove wall 1131. One end of the first groove wall 1131 far from the center of the housing 110 is connected to one end of the transition portion 116. The other end of the transition portion 116 is connected to one end of the main body portion 115 far from the end wall 114. The structure of the transition portion 116 may be any structure that can achieve a smooth transition and connection between the main body portion 115 and the roll groove 113, such as an arc structure or an inclined structure.

[0036] As shown in FIG. 2 , the electrode assembly 120 is housed within the housing 110. The electrode assembly 120 is the component where the electrochemical reaction occurs in the cylindrical battery 100. The housing 110 may contain one or more electrode assemblies 120. The electrode assembly 120 is typically formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and typically a separator is provided between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is applied to the surface of the positive electrode current collector. The positive electrode current collector includes a positive electrode application area and a positive electrode tab connected to the positive electrode application area. The positive electrode application area is coated with the positive electrode active material layer, while the positive electrode tab is not coated with the positive electrode active material layer. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is applied to the surface of the negative electrode current collector. The negative electrode current collector includes a negative electrode coating area and a negative electrode tab connected to the negative electrode coating area. A negative electrode active material layer is coated on the negative electrode coating area, while no negative electrode active material layer is coated on the negative electrode tab. Taking a lithium-ion battery as an example, the positive electrode current collector may be made of aluminum, the positive electrode active material layer includes a positive electrode active material, which may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode current collector may be made of copper, and the negative electrode active material layer includes a negative electrode active material, which may be carbon or silicon. The separator may be mainly made of PP or PE. To provide protection and insulation to the electrode assembly 120, the exterior of the electrode assembly 120 may be covered with an insulating film, which may be made of PP, PE, PET, PVC, or other polymer materials.

[0037] 1 and 2, in one example of a cylindrical battery of the present invention, an electrode assembly 120 is hermetically mounted within a housing 110. The electrode assembly 120 is disposed between an end wall 114 and a roll groove 113 along the height direction of the cylindrical battery 100, and the roll groove 113 can restrict axial movement of the electrode assembly 120 between the end wall 114 and the roll groove 113. The electrode assembly 120 is provided with a first tab 121 and a second tab 122 at both ends of the height direction of the cylindrical battery 100, respectively, and the first tab 121 and the second tab 122 have opposite polarities. The first tab 121 is on the side facing the opening 112 and is a negative electrode tab. It should be noted that in other embodiments, the first tab 121 may be a positive electrode tab and the second tab 122 may be a negative electrode tab.

[0038] 1 to 3 , an end cap 150 is provided at the opening 112. The outer periphery of the end cap 150 is engaged by a seal ring 170 between the extension 117, the connection portion 118, and the roll groove 113, thereby achieving a sealed and fixed connection at the opening 112 of the end cap 150. The current collecting member 130 is provided in the housing 110 and is positioned between the end cap 150 and the electrode assembly 120. The current collecting member 130 includes a current collecting body 131 and a connection piece 132 connected to the periphery of the current collecting body 131. There are several options for the connection method, such as welding, or any other connection method that can achieve an electrical connection between the connection piece 132 and the current collecting body 131, such as an integral connection. In this embodiment, the connection piece 132 and the current collecting body 131 are an integral press-formed member to improve assembly efficiency. The current collecting body 131 is electrically connected to the first tab 121. There are several options for the electrical connection method, and any connection method that can achieve electrical connection between the connection piece 132 and the first tab 121 may be used, such as welding, conductive adhesive bonding, etc. In this embodiment, the current collecting body 131 and the first tab 121 are welded together. It should be noted that providing the connection piece 132 on the periphery of the current collecting body 131 means that the connection piece 132 and the outer edge of the current collecting body 131 are connected along the radial direction of the current collecting body 131.

[0039] The connecting piece 132 is located between the first groove wall 1311 and the electrode assembly 120 along the height direction of the cylindrical battery 100. The number of connecting pieces 132 is not limited and may be one or more. At the same time, the specific shape and area of ​​the connecting piece 132 are not limited as long as they satisfy the requirements of the welding strength and current guiding area between the connecting piece 132 and the housing 110. The connecting piece 132 is located on the side of the current collecting body 131 away from the electrode assembly 120. One end of the connecting piece 132 is connected to the periphery of the current collecting body 131. The other end of the connecting piece 132 is bent toward the axis of the housing 110 and welded to the first groove wall 131 to form a weld 140. The specific shape of the bend of the connecting piece 132 is not limited, and may be, for example, a substantially U-shape, a substantially triangular shape, etc. after bending, as long as it is possible to ensure that a partial region of the connecting piece 132 forms a weld 140 that satisfies the connection strength requirements between the connecting piece 132 and the first groove wall 1131. Providing the connecting piece 132 on the periphery of the current collecting body 131 facilitates welding between the current collecting member 130 and the housing 110, and allows for more flexibility in the welding position between the current collecting member 130 and the housing 110. A gap exists between the connecting piece 132 and the side wall 111 and the portion between the weld 140 and the periphery of the current collecting body 131. The existence of a gap means that a gap exists in one of the following three places: the portion between the welded portion 140 of the connecting piece 132 and the periphery of the current collecting body 131; the first groove wall 1131 located between the welded portion 140 and the transition portion 116; the inner wall of the transition portion 116; and the inner wall of the main body portion 115 at the connection position with the transition portion 116. A gap may also exist in any two of these places, or in any of the three places.

[0040] In this configuration, when roll grooving is performed near the opening of the casing 110, a gap exists between the side wall 111 and the portion between the weld 140 of the connection piece 132 and the periphery of the current collecting body 131, thereby reducing the extrusion pressure that the side wall 111 generates against the weld 140 and reducing the possibility that the connection piece 132 will be displaced relative to the wall of the roll groove 113 at the position of the weld 140, effectively improving the stability of the welding between the connection piece 132 and the casing 110. This improves the stability of the electrical connection between the electrode assembly 120 and the casing 110 and the yield of the cylindrical battery 100, ensuring the usability of the cylindrical battery 100.

[0041] 1 and 2, in one example of the cylindrical battery 100 of the present invention, there is no contact between the portion between the welding portion 140 of the connection piece 132 and the periphery of the current collecting body 131 and the side wall 111. "No contact" specifically means that the portion between the welding portion 140 of the connection piece 132 and the periphery of the current collecting body 131 does not contact any of the first groove wall 1131 located between the welding portion 140 and the transition portion 116, the inner wall of the transition portion 116, and the inner wall of the main body portion 115 at the connection position with the transition portion 116. This configuration can further reduce the extrusion pressure from the side wall 111 that is received by the portion of the connection piece 132 located between the welded portion 140 and the periphery of the current collecting body 131 during roll grooving, thereby further reducing the possibility of the connection piece 132 being displaced relative to the wall of the roll groove 113 at the position of the welded portion 140, and further increasing the stability of the welding between the connection piece 132 and the roll groove 113.

[0042] It should be noted that in this embodiment, "the portion between the welded portion 140 of the connecting piece 132 and the periphery of the current collecting body 131 is not in contact with the side wall 111" means that the portion between the welded portion 140 of the connecting piece 132 and the periphery of the current collecting body 131 is not in uniform contact with the side wall 111 overall along the circumferential direction of the side wall 111. In other words, the portion between the welded portion 140 of the connecting piece 132 and the periphery of the current collecting body 131 is not in uniform contact with the first groove wall 1131 located between the welded portion 140 and the transition portion 116, the inner wall of the transition portion 116, and the inner wall of the main body portion 115 at the connection position with the transition portion 116 along the circumferential direction of the side wall 111.

[0043] 1 and 2 , in one example of the cylindrical battery 100 of the present invention, the current collecting member 130 preferably includes a plurality of connecting pieces 132, which are arranged around the outer periphery of the current collecting body 131. The connecting pieces 132 may have the same structure or different structures, as long as they meet the current guiding and welding strength requirements between the current collecting member 130 and the housing 110. For convenient positioning and connection between the connecting pieces 132 and the current collecting member 130, in this embodiment, the connecting pieces 132 have the same shape and are arranged in a row along the circumferential direction of the current collecting body 131. This configuration produces a more uniform current guiding effect between the current collecting member 130 and the side wall 111 in the circumferential direction, thereby improving the stability of current guiding between the housing 110 and the electrode assembly 120.

[0044] The connection piece 132 between the first groove wall 1131 and the current collecting body 131 may have multiple bent shapes. However, for convenience in welding between the connection piece 132 and the side wall 111, in one example of the cylindrical battery 100 of the present invention, referring to FIGS. 2 and 3 , the connection piece 132 preferably includes a first connection portion 1321 and a second connection portion 1322 connected to each other. The portion located between the welded portion and the current collecting body is the first connection portion, and the welded portion 140 is formed between the second connection portion 1322 and the first side wall 1131. The second connection piece 1322 extends into the interior of the housing 110 from one end of the first connection portion 1321 close to the welded portion 140. The extension direction of the second connecting portion 1322 may coincide with the radial direction of the housing 110 or may be angled relative to the radial direction of the housing 110, as long as it is possible to ensure that the second connecting portion 1322 forms a stable weld 140 with the first groove wall 1131. The second connecting portion 1322 may have a substantially flat straight segment structure or another bent structure that can achieve welding with the first groove wall 1131. In this embodiment, the second connecting portion 1322 preferably has a substantially flat straight segment structure that extends at an angle toward the electrode assembly 120. This is advantageous for controlling the welding distance between the second connecting portion 1322 and the first groove wall 1131 and for improving controllability of the welding quality of the weld 140.

[0045] Along the height direction of the housing 110, one end of the first connecting portion 1321 farther from the current collecting body 131 is inclined toward the axial direction of the housing 110, a bend angle is formed between the first connecting portion 1321 and the second connecting portion 1322, and a first bent portion 1323 is formed at one end near the boundary of the first connecting portion 1321. During the roll grooving process, bending deformation may occur in the connecting piece 132, and the deformation stress generated by the bending deformation may be partially transmitted to the welded portion 140, causing some damage to the welded portion 140 and, in severe cases, causing the connecting piece 132 to fall off from the welded portion 140. In this embodiment, by providing the first bent portion 1323 at one end of the boundary near the side wall 111, the bending deformation of the first bent portion 1323 can absorb some of the deformation stress, thereby reducing the transmission of the deformation stress of the first connecting portion 1321 to the second connecting portion 1322 during the roll grooving process. This reduces the deformation stress of the first connecting portion 1321 from pushing out and damaging the welded portion 140, and effectively improves the stability of the weld between the connecting piece 132 and the side wall 111.

[0046] To facilitate bending deformation of the connecting piece 132 during the roll grooving process and reduce deformation stress generated in the connecting piece 132 during the bending process, in one example of the cylindrical battery 100 of the present invention, the thickness of the connecting piece 132 is preferably any value within a range of 0.1 to 0.3 mm, such as 0.1 mm, 0.2 mm, or 0.3 mm. Limiting the thickness of the connecting piece 132 within this range not only facilitates bending deformation of the connecting piece 132 during the roll grooving process, but also reduces deformation stress generated in the connecting piece 132 and effectively ensures the integrity of the weld 140. At the same time, it also satisfies the current guide requirements between the connecting piece 132 and the side wall 111, ensuring the normal use performance of the cylindrical battery 100.

[0047] 2, 4, and 5, in one example of the cylindrical battery 100 of the present invention, the first bent portion 1323 extends along the circumferential direction of the side wall 111, and the first bent portion 1323 is provided with a first fragile structure 1324. Along the extension direction of the first bent portion 1323, the first fragile structure 1324 may be a partial structure provided in the middle or both ends of the first bent portion 1323, or may be a complete structure surrounding the entire first bent portion 1323. There are several specific structural forms of the first fragile structure 1324, such as a through-hole structure provided in the first bent portion 1323 or a thinned region structure formed in the first bent portion 1323, as long as it can weaken the bending strength of the first bent portion 1323 and facilitate bending of the first bent portion 1323. The provision of the first fragile structure 1324 at the first bending portion 1323 not only facilitates bending of the first bending portion 1323, but also reduces the transmission of deformation stress generated in the first connecting portion 1321 to the welded portion 140. At the same time, the first fragile structure 1324 provides a function of guiding the bending of the first bending portion 1323, which can improve the accuracy of the bending position of the first bending portion 1323 and contributes to improving the consistency of the assembly quality of the cylindrical battery 100. In addition, when welding the connecting piece 132 and the side wall 111 before roll grooving, the first fragile structure 1324 can also serve as a reference line for the welding position, which facilitates the positioning of the welding head during welding.

[0048] FIG. 9 is a structural diagram of one embodiment of a cylindrical battery of the present invention, showing the connection piece before bending. FIG. 10 is a cross-sectional view of the current collecting member of the embodiment of FIG. 9. FIG. 11 is a partially enlarged view of region D in FIG. 10. Referring to FIGS. 9 to 11, in one example of a cylindrical battery 100 of the present invention, the first fragile structure 1324 preferably includes a thinned region 1327 provided in the first bent portion 1323. The thinned region 1327 may take various forms, such as a cut region formed by cutting the surface of the first bent portion 1323, or a thinned region formed by thinning the surface of the first bent portion 1323. By providing the thinned region 1327 in the first bent portion 1323, a bending fragile portion is formed in the first bent portion 1323, thereby reducing the bending strength of the first bent portion 1323. This allows the connection piece 132 to be deformed more timely and quickly in the region of the first bent portion 1323 during the roll grooving process, thereby further reducing the transmission of deformation stress generated on the first connection portion 1321 side to the welded portion 140. It should be noted that the thinned region 1327 may be provided on the surface of the first bent portion 1323 facing the current collecting body 131, or on the surface of the first bent portion 1323 away from the current collecting body 131. In this embodiment, the thinned region 1327 is preferably provided on the surface of the first bent portion 1323 facing the current collecting body 131. This not only reduces the possibility of fracture damage to the thinned region 1327 during the bending process, but also better ensures the stability of the electrical connection between the connection piece 132 and the housing 110. In addition, when welding the connection piece 132 and the side wall 111 inside the housing 110, the thinned area 1327 provided on the connection piece 132 can also be used as a positioning reference for the welding position, which is convenient for positioning the welding between the connection piece 132 and the side wall 111.

[0049] Fig. 4 is a structural diagram of one embodiment of a cylindrical battery of the present invention after the connecting piece has been bent. Fig. 5 is a partial enlarged view of region B in Fig. 4. Fig. 6 is a structural diagram of the connecting piece of the embodiment of Fig. 4 before it has been bent. Fig. 7 is a cross-sectional view of the current collecting member of the embodiment of Fig. 6. Fig. 8 is a partial enlarged view of region C in Fig. 7. Referring to Figs. 4 to 8, in one example of a cylindrical battery 100 of the present invention, the first fragile structure 1324 further includes an openwork region 1328 provided in the first bent portion 1323. The specific shape of the openwork region 1328 is not limited. For example, it may be a openwork region 1328 formed by a plurality of circular through holes arranged along the extension direction of the first bent portion 1323, a openwork region 1328 formed by a plurality of rectangular through holes arranged along the extension direction of the first bent portion 1323, or even a openwork region 1328 formed by a single approximately strip-shaped through hole arranged along the extension direction of the first bent portion 1323. In this embodiment, the openwork region 1328 preferably has a structure in which a plurality of strip holes are arranged in an array along the extension direction of the first bent portion 1323. By providing the openwork region 1328 in the first bent portion 1323, a bending weakened portion is formed in the first bent portion 1323, reducing the bending strength of the first bent portion 1323 and enabling the connecting piece 132 to deform timely and quickly during the roll grooving process. It can also provide a welding positioning function when welding the connecting piece 132 and the side wall 111 inside the housing 110.

[0050] It should be noted that the first weakened structure 1324 provided in the first bent portion 1323 may simultaneously include the thinned region 1327 and the hollowed region 1328, which can also achieve the effect of causing bending in the first bent portion 1323 during the roll grooving process in the above-mentioned embodiment.

[0051] In one example of the cylindrical battery 100 of the present invention, the first connection portion 1321 is bent toward the center of the current collecting body 131, and a second bent portion 1325 is formed at one end of the first bent portion 1323 closest to the current collecting body 131. FIG. 3 is a structural diagram of the position of the weld after roll grooving in one embodiment of the cylindrical battery of the present invention. As shown in FIG. 3, the provision of the second bent portion 1325 reduces the transmission of deformation stress generated when the connection piece 132 is bent and deformed to the current collecting body 131 during the roll grooving process, thereby reducing stress deformation of the current collecting body 131. This effectively protects the stability of the weld between the current collecting body 131 and the first tab 121.

[0052] FIG. 6 is a structural diagram of the embodiment of FIG. 4 before the connecting piece is bent. FIG. 7 is a cross-sectional view of the current collecting member of the embodiment of FIG. 6. FIG. 8 is a partial enlarged view of region C in FIG. 7. Referring to FIGS. 6 to 8, in one example of the cylindrical battery 100 of the present invention, the second bent portion 1325 extends along the circumferential direction of the side wall 111, and the second bent portion 1325 is provided with a second fragile structure 1326. The second fragile structure 1326 may be a partial structure provided in the middle or at both ends of the second bent portion 1325, or may be an entire structure that surrounds the entire second bent portion 1325. The second frangible structure 1326 may have a variety of specific structural forms, such as a through-hole structure provided in the second bent portion 1325 or a thinned region structure formed in the second bent portion 1325, as long as it can weaken the bending strength of the second bent portion 1325 and is convenient for forming a bend in the second bent portion 1325. Providing the second frangible structure 1326 in the second bent portion 1325 is convenient for forming a bend in one end of the first connection portion 1321 close to the current collecting body 131, thereby preventing bending stress generated in the first connection portion 1321 from being transferred to the current collecting body 131 and causing the weld between the current collecting body 131 and the first tab 121 to break, and improving the stability of the electrical connection between the current collecting body 131 and the electrode assembly 120.

[0053] 12 illustrates another embodiment of a cylindrical battery according to the present invention, in which a frangible structure is provided at both the first and second bent portions. Referring to FIG. 12 , in this embodiment, a first frangible structure 1324 is provided at the first bent portion 1323, and a second frangible structure 1326 is provided at the second bent portion 1325. With this configuration, the first frangible structure 1324 can guide the bending of the first bent portion 1323, and the second frangible structure 1326 can also guide the bending of the second bent portion 1325. This allows for accurate control of the bending path of the connecting piece 132 during the roll grooving process, improving controllability of the bending deformation of the connecting piece 132 during the roll grooving process, and contributing to an improvement in the assembly yield rate of the cylindrical battery 100.

[0054] FIG. 13 is a partially enlarged view of a welded portion after roll grooving in one embodiment of a cylindrical battery of the present invention. FIG. 17 is a partial view of the overlapping position between the connection piece 132 and the side wall 111 before roll grooving in one embodiment of a cylindrical battery of the present invention. Referring to FIGS. 13 and 17, in one example of a cylindrical battery 100 of the present invention, the developed length size from one end of the connection piece 132 connecting with the current collecting body 131 to the free end of the connection piece 132 is A. That is, the size from the end of the connection piece 132 connecting with the current collecting body 131 to its end before bending is indicated by the size A in FIG. 17. This size is obtained by measuring the product outer size of the current collecting member 130 before roll grooving (the measurement method in the reverse case is the sum of the developed size or the length of the outer contour). The minimum distance between the second bent portion 1325 and the inner wall of the side wall 111 along the radial direction of the housing 110 is Δ. As shown in FIGS. 13 and 17 , the minimum distance Δ is obtained by directly measuring the gap between the second bent portion 1325 and the inner wall of the side wall 111, and is also obtained by subtracting the inner diameter R1 of the side wall 111 from the outer diameter R2 of the current collecting member 130. The sizes R1 and R2 are labeled in FIG. 17 . The extension length of the second connecting portion 1322 is F. As shown in FIG. 13 , the width of the welded portion 140 at the second connecting portion 1322 along the extension direction of the second connecting portion 1322 is W. The size W is obtained by measurement and satisfies the following condition: 0.2 mm + W≦F≦(0.05 mm×A) / Δ.

[0055] FIG. 17 is a partial view of the overlapping position between the connection piece 132 and the side wall 111 before roll grooving in one embodiment of a cylindrical battery of the present invention. In combination with FIG. 17 , in this embodiment, after the current collecting member 130 is installed in the housing 110, the connection piece 132 on the current collecting member 130 and the side wall 111 are configured to have an inclined overlap, with an included inclination angle β, to facilitate insertion of the current collecting member 130 into the housing and to meet the requirements for the welding position between the connection piece 132 and the side wall 111. The height size A of the connection piece 132 is generally any value within the range of 2 to 4 mm, and values ​​within this size range can meet the requirements for the welding position between the connection piece 132 and the side wall 111 in a typical cylindrical battery 100. Referring to FIG. 17 , a roughly triangular gap distribution is formed between the connection piece 132 and the side wall 111 along the height direction of the side wall 111, with the gap value being smallest on the side closer to the opening 112 and largest on the side closer to the electrode assembly 120. During the actual welding process of the connection piece 132 and the side wall 111, the inventors discovered that if the gap between the connection piece 132 and the side wall 111 is too large (i.e., if the welding position between the connection piece 132 and the side wall 111 is too close to the electrode assembly 120), welding spatter is likely to occur at the weld 140 formed between the connection piece 132 and the side wall 111, resulting in poor welding quality and affecting the current flow requirements between the connection piece 132 and the side wall 111. Therefore, to achieve excellent welding quality between the connection piece 132 and the side wall 111 during the actual welding process, it is necessary to find a maximum gap value that satisfies the welding quality requirements between the connection piece 132 and the side wall 111. The maximum gap value that satisfies the welding quality requirements between the connection piece 132 and the side wall 111 is set as a safety gap, shown as size B in FIG. 17 . The connection piece and the side wall come into contact with each other to form an intersection M. The triangular area enclosed by the three points K, N, and M is the weld-waiting area 180, and the line KN is the lower edge 182 of the weld-waiting area 180. When the length of the line KN is equal to the size B, the weld located within the weld-waiting area 180 has excellent weld quality and can achieve excellent weld strength between the connecting piece 132 and the side wall 111.

[0056] In order to determine the value of the safety gap B, the inventors in this invention adopt certain testing methods, and after multiple tests, find that the most suitable size of the safety gap B is 0.05 mm. The specific experimental method and steps are as follows: (1) A plurality of assemblies each including a current collecting member 130 and a housing 110 were prepared. Five identical current collecting members 130 and five identical housings 110 were selected, and the five current collecting members 130 were installed in the five housings 110 based on an assembly relationship. The five current collecting members 130 are labeled 1#, 2#, 3#, 4#, and 5#, respectively. (2) Different welding gaps were formed between the connection pieces 132 of the five current collecting members 130 and the corresponding housings 110 . 1# The connection piece 132 of the current collecting member 130 was in direct contact with the side wall 111 of the housing 110. That is, the welding gap between the connection piece 132 and the side wall 111 was zero. 2# One piece of 0.025 mm thick adhesive tape was attached to the side of the connection piece 132 of the current collecting member 130 facing the side wall 111 of the housing 110, and then the connection piece 132 was pressed onto the side wall 111 of the housing 110, leaving a welding gap of 0.025 mm between the connection piece 132 and the side wall 111. 3# Two pieces of 0.025 mm thick adhesive tape were attached to the side of the connection piece 132 of the current collecting member 130 facing the side wall 111 of the housing 110, and then the connection piece 132 was pressed onto the side wall 111 of the housing 110, leaving a welding gap of 0.05 mm between the connection piece 132 and the side wall 111. 4# Three pieces of 0.025 mm thick adhesive tape were attached to the side of the connecting piece 132 of the current collecting member 130 facing the side wall 111 of the housing 110, and then the connecting piece 132 was pressed against the side wall 111 of the housing 110, leaving a welding gap of 0.075 mm between the connecting piece 132 and the side wall 111. 5# Four pieces of 0.025 mm thick adhesive tape were attached to the side of the connecting piece 132 of the current collecting member 130 facing the side wall 111 of the housing 110, and then the connecting piece 132 was pressed against the side wall 111 of the housing 110, leaving a welding gap of 0.1 mm between the connecting piece 132 and the side wall 111. (3) By welding the assembly of the five current collecting members 130 and the housing 110 described above, corresponding welds 140 were formed between the connection pieces 132 and the side walls 111 of the housing 110. The welds 140 formed between the five current collecting members 130 and the corresponding housings 110 are respectively labeled weld a, weld b, weld c, weld d, and weld e. (4) A peel test was performed on each of the welds a to e.

[0057] A shear tensile test method was used to perform the peel test on welds a-e. First, a cylindrical tool 400 was prepared. One axial end of the cylindrical tool 400 was connected to the working end of a universal tensile tester. The assembly of the current collecting member 130 and the housing 110 was placed directly below the cylindrical tool, and a universal tensile test was performed. As shown in Figure 26, the cylindrical tool 400 was moved axially downward, contacting and compressing the current collecting body 131 of the current collecting member 130. The pressure applied by the cylindrical tool 400 to the current collecting body 131 was continuously increased. This increased the tensile force applied to weld a until the connection piece 132 was peeled off from weld a. The tensile value of the universal tensile tester and the fracture effect of weld a at the time of peeling were recorded, completing the peel test on weld a. Figure 26 illustrates the peel test being performed on the weld formed between the connection piece and the side wall of the present invention.

[0058] The above steps were repeated to complete the peel test for each of welds b to e, and the corresponding test tensile force values ​​and peel effects were recorded as shown in Table 1. Table 1: Test tensile forces and pull-off results for welds formed with different weld gaps [Table 1]

[0059] As shown in Table 1, when the welding gap between the connecting piece 132 and the side wall 111 is 0.05 mm or less, it is possible to ensure a desirable connection strength between the connecting piece 132 and the side wall 111. This ensures that the connecting piece 132 will not easily come off the side wall 111 when the housing 110 is roll grooved.

[0060] At the same time, the magnitude of the test tensile force values ​​shown in Table 1 indicates that the test tensile force value when the connecting piece 132 is peeled off from the housing 110 is positively correlated with the weld gap between the connecting piece 132 and the side wall 111. That is, the smaller the weld gap, the larger the test tensile force value, which indicates a higher connection strength of the weld 140 formed between the connecting piece 132 and the housing 110. Furthermore, when the weld gap between the connecting piece 132 and the side wall 111 is 0.05 mm or less, the change trend of the test tensile force value is relatively stable, but when the weld gap between the connecting piece 132 and the side wall 111 is larger than 0.05 mm, the test tensile force value decreases sharply. As a result, when the welding gap between the connection piece 132 and the side wall 111 is larger than 0.05 mm, the connection strength of the weld 140 formed between the connection piece 132 and the housing 110 is significantly reduced, and it can be inferred that the connection piece 132 will easily fall off from the side wall 111 when roll grooving the housing 110.

[0061] By referring to the experimental results in Table 1 and the diagrams of weld peeling effects shown in Figures 23 to 25, it can be seen that in this embodiment, it is appropriate to set the welding gap between the connection piece 132 and the side wall 111, i.e., the safety gap B, to 0.05 mm. Figure 17 is a partial view of the overlap position between the connection piece and the side wall before roll grooving in one embodiment of a cylindrical battery of the present invention. Figure 18 is a view of the distribution of the welding-waiting area between the connection piece and the side wall before roll grooving in one embodiment of a cylindrical battery of the present invention. Combining Figures 17 and 18, the distance between the lower edge 182 and the intersection point M is defined as size C, and C = B / tan β. If the distance between point K and point M along the extension direction of the connection piece 132 is defined as L, L = (B × A) / Δ can be derived from the equations sin β = B / L and sin β = Δ / A. Introducing B = 0.05 mm, Lmax = (0.05 × A) / Δ is obtained. That is, when welding is performed on the weld waiting area 180, if the position where the weld 140 is formed on the connecting piece 132 is within the area between point K and point M, the weld quality between the connecting piece 132 and the side wall 111 is good, problems such as welding spatter do not occur, and a stable current guiding area between the connecting piece 132 and the side wall 111 can be ensured. FIG. 13 is a partially enlarged view of the weld after roll grooving in one embodiment of the cylindrical battery of the present invention. In combination with FIG. 13, it can be seen that after bending the connecting piece 132, the extension length size F of the second connecting portion 1322 is approximately equal to the size L in FIG. 17. That is, Fmax = Lmax = (0.05 × A) / Δ. At the same time, when welding the edge of the connecting piece 132 away from the current collecting member 130 and the overlapping position of the inner wall of the side wall 111, a butt weld is used, resulting in a shallow weld pool and insufficient molten metal to fill the weld pool. This reduces the strength of the weld 140 and can easily lead to the connecting piece 132 falling off the side wall 111 during the roll grooving process. At the same time, undercutting can easily occur, resulting in poor appearance of the welded product. In view of this, in this embodiment, as shown in FIG. 17 , a weld-waiting area 180 is entirely positioned below the intersection point M along the height direction of the side wall 111. As indicated by the line JS in FIG. 17 , the side of the weld-waiting area 180 closest to the opening 112 includes an upper edge 181.One end of the upper edge 181 intersects with the inner wall of the side wall 111 to form an intersection S, and the other end of the upper edge 181 intersects with the connecting piece 132 to form an intersection J. Through multiple experimental studies, the inventors discovered that when the length D of the line MJ is 0.2 mm or more, excellent weld strength is achieved between the connecting piece 132 and the side wall 111, and problems such as undercuts and poor weld appearance are unlikely to occur. Figure 13 is a partially enlarged view of a weld after roll grooving in one embodiment of a cylindrical battery of the present invention. Referring again to Figure 13, the minimum size F of size F is 1. min It can be seen that F is 0.2 mm + W. From this, it can be inferred that if 0.2 mm + W ≦ F ≦ (0.05 mm × A) / Δ, it can be determined that there is excellent welding strength between the connection piece 132 and the side wall 111.

[0062] Using the conversion relationship between the sizes L and F described above, the limit position parameter on the connection piece 132 of the weld 140 before roll grooving deformation can be converted and expressed as the limit length size of the second connection portion 1322 after roll grooving. This configuration allows for a determination of whether the measured value of size F satisfies the relationship 0.2 mm + W≦F≦(0.05 mm×A) / Δ simply by measuring the size F of the completed cylindrical battery 100, thereby estimating the installation position of the weld 140 on the connection piece 132 before roll grooving. This allows for a further determination of whether the weld quality of the weld 140 is good, eliminating the need to verify the weld quality of the weld 140 by performing cumbersome tests such as tensile fracture tests on the weld 140 again. This further speeds up the development process of new products and reduces the number of verification stages for new products.

[0063] Referring to FIG. 13, FIG. 13 is a partially enlarged view of the welded portion after roll grooving in one embodiment of the cylindrical battery of the present invention. In one example of the cylindrical battery 100 of the present invention, the length of the second connection portion 1322 is F, and the width of the welded portion 140 along the extension direction of the second connection portion 1322 is W, where W≦F≦0.05 mm / sin4. From the derivation formula sinβ=B / L in the above embodiment, it can be inferred that by introducing size B=0.05 mm, size Lmax=0.05 / sinβ can be calculated. FIG. 17 is a partial view of the overlap position between the connection piece and the side wall of one embodiment of the cylindrical battery of the present invention before roll grooving. 17 in combination with Fig. 17, it can be seen that when the included inclination angle β between the connecting piece 132 and the side wall 111 increases, the size Δ also increases, and phenomena such as scratches or snagging between the connecting piece 132 and the side wall 111 are less likely to occur during the process of inserting the current collecting member 130 into the housing, but the contact force between the connecting piece 132 and the side wall 111 decreases, resulting in poorer radial positioning accuracy between the current collecting member 130 and the side wall 111. Conversely, as the size Δ decreases, phenomena such as scratches or snagging between the connecting piece 132 and the side wall 111 are more likely to occur during the process of inserting the current collecting member 130 into the housing, but the contact force between the connecting piece 132 and the side wall 111 increases, resulting in better radial positioning accuracy between the current collecting member 130 and the side wall 111. In consideration of this, the inventors conducted multiple tests during actual production and found that setting the included inclination angle β between 1° and 4° facilitates insertion of the current collecting member 130 into the housing and provides excellent positioning accuracy between the current collecting member 130 and the side wall 111. Because errors in the included inclination angle β may occur during the manufacturing or assembly process, the included inclination angle β of an actual product may be any value within the range of 1° to 4°, such as 1°, 2°, or 3°. In actual design, the upper and lower limits of the included inclination angle β are relatively reliable: 1° and 4°, respectively. Therefore, in this embodiment, the maximum value of L is set to 0.05 / sin4. This configuration ensures that all values ​​of the included inclination angle β between 1° and 4° can uniformly meet the welding requirements.In this embodiment, the relationship between F and K is established through the included inclination angle β. Therefore, simply measuring the size F of the completed cylindrical battery 100 allows us to determine whether F satisfies the relationship 0.2 mm + W≦F≦0.05 mm / sin4. This allows us to infer whether the position of the weld 140 before roll grooving is appropriate and whether the weld quality between the connecting piece 132 and the side wall 111 is good. This eliminates the need to perform tedious tests such as tensile fracture on the weld 140 to verify the weld quality, further accelerating the development process of new products and reducing the number of verification stages for new products. At the same time, the verification process requires only one intermediate parameter, the width W of the weld 140, which can be directly measured. Therefore, the maximum and minimum limits of size F can be easily calculated using this formula, making the verification process relatively simple and widespread. Figure 18 is a diagram showing the distribution of the waiting-for-weld areas between the connecting piece and the side wall before roll grooving in one embodiment of a cylindrical battery of the present invention. Referring to FIG. 18, the inventors discovered that in actual production, the thicknesses of both the connecting piece 132 and the side wall 111 are small, resulting in a small welding process window between the side wall 111 and the connecting piece 132 during the welding process, making it difficult to control the welding quality. Therefore, the inventors proposed adopting an inclined welding technique as shown in FIG. 19. FIG. 19 is a diagram of the welding position between the welding head and the side wall before roll grooving in one embodiment of a cylindrical battery of the present invention. That is, the welding operation is performed with the welding head 160 and the side wall 111 in an inclined position. In this way, the weld 140' shown in FIG. 18 can be formed during the welding process. The weld 140' has an inclined molten pool 141'. The contour line 1411' of the molten pool 141' intersects with the inner wall of the side wall 111 to form an intersection Q, and an included angle ω is formed between the tangent to the contour line 1411' passing through this intersection Q (shown as the straight line YY in Figure 19) and the inner wall of the side wall 111, and the included angle ω is an obtuse angle.

[0064] FIG. 16 is a diagram illustrating the positions of the weld pool and the side wall and the connecting piece in one embodiment of the cylindrical battery of the present invention. Referring to FIG. 16, in one example of the cylindrical battery 100 of the present invention, the welded portion 140 includes a weld pool 141, which corresponds to the weld pool 141' in FIG. 19. In an axial cross section passing through the weld pool 141 of the cylindrical battery 100, the weld pool 141 forms a contour line 1411, which corresponds to the contour line 1411' in FIG. 19. The contour line 1411 of the weld pool 141 includes a substantially linear contour formed on the side of the second connection portion 1322 facing the electrode assembly 120 and a substantially curved contour formed on the side of the second connection portion 1322 away from the electrode assembly 120. The opening direction of the curved contour is the side facing the electrode assembly 120, and both ends of the linear contour are connected to both ends of the curved contour. The curved profile extends at least partially into the first groove wall 1131. A first intersection point H is formed along the radial direction of the housing 110 between a side of the curved profile away from the axis of the housing 110 and a side of the first groove wall 1311 facing the second connecting portion 1322. The first intersection point H corresponds to the intersection point Q in FIG. 19 . An obtuse angle θ, which is away from the axis of the housing 110, is formed between a tangent to the curved profile (shown as the line XX in FIG. 16 ) and the first groove wall 1311. The obtuse angle θ corresponds to the included angle ω in FIG. 19 . On the other hand, the obtuse angle θ reduces stress concentration on the side of the molten pool 141 near the first bend portion 1323 during the roll grooving process, thereby increasing the connection strength of the weld 140 and reducing the possibility of the weld 140 losing effectiveness and the connecting piece 132 falling off the side wall 111.

[0065] Referring to FIG. 2 , in one example of a cylindrical battery of the present invention, at least a portion of the central region of the current collecting body 131 protrudes toward the opening 112 of the casing 110 along the axial direction of the casing 110 and is higher than the peripheral region of the current collecting body 131 covered by the roll groove 113. The type of protruding structure is not limited, and may be, for example, an arc-shaped protruding structure, a truncated conical protruding structure, or even a structure combining a plurality of different shapes, as long as at least a portion of the central region of the current collecting body 131 is higher than the peripheral region of the current collecting body 131 covered by the roll groove 113. This configuration brings the central region of the current collecting body 131 closer to the end cap 150, increasing the accommodation space for the electrode assembly 120 below the current collecting body 131. Therefore, the volumetric energy density of the cylindrical battery 100 can be increased when the height of the casing 110 is constant.

[0066] 20 and 21 , the present invention further provides an electronic device 300. The electronic device 300 includes a battery assembly 200 and an operating unit 310. The operating unit 310 is electrically connected to the battery assembly 200 to obtain power support. As an example, the electronic device 300 is a vehicle. The vehicle may be a fuel-powered vehicle, a gas-powered vehicle, or a new energy vehicle. The new energy vehicle may be, but is not limited to, a pure electric vehicle, a hybrid vehicle, or a range-extending vehicle. The operating unit 310 is a vehicle body, and the battery assembly 200 is installed at the bottom of the vehicle body and provides power support for running the vehicle or operating electrical components inside the vehicle. In other embodiments, the electronic device 300 may be a mobile phone, a portable device, a notebook computer, a boat, an airplane, an electric toy, an electric tool, or the like. Aircraft include airplanes, rockets, space shuttles, spacecraft, and the like. The operating unit 310 may be a unit component that receives electric energy from the battery assembly 200 and performs a corresponding operation, such as a blade rotation unit of an electric fan or a dust collection unit of a vacuum cleaner. Electric toys include stationary or mobile electric toys, such as game consoles, electric toy cars, electric toy boats, and electric toy airplanes. Electric tools include metal cutting tools, grinding tools, assembly tools, and railroad tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planes. The embodiments of the present invention are not particularly limited to the electronic device 300 described above.

[0067] Referring to FIG. 20 , the battery assembly 200 described above includes any one of the cylindrical batteries 100 described above. In one embodiment of the battery assembly 200 of the present invention, the battery assembly 200 includes a case 210, a lid 220, and a plurality of cylindrical batteries 100. The plurality of cylindrical batteries 100 are arranged in the case 210 and connected to each other in series or parallel, or a combination of series and parallel. The lid 220 covers the case 210 to protect the plurality of cylindrical batteries 100. It should be noted that the battery assembly 200 may include not only the cylindrical battery 100 of the present invention but also other components such as a thermal management system and a circuit board of the battery assembly 200. The battery assembly 200 may be a battery module, a battery pack, an energy storage cabinet, etc., each of which will not be described here.

[0068] Referring to Fig. 22, the present invention further provides a manufacturing method for a cylindrical battery 100. The manufacturing method is used to manufacture and form the cylindrical battery 100 of the above-described embodiment. The cylindrical battery 100 includes a housing 110, an electrode assembly 120, a current collecting member 130, and an end cap 150. The housing 110 includes a peripheral side wall, and an opening 112 is formed at one end of the side wall 111. The current collecting member 130 includes a current collecting body 131 and a connecting piece 132 fixedly connected to the periphery of the current collecting body 131. The manufacturing method includes the following steps: S1: The current collecting body 131 of the current collecting member 130 is welded to the first tab 121 of the electrode assembly 120 to form a cell assembly. There are no limitations on the specific location and area of ​​the weld between the current collecting body 131 and the first tab 121, as long as it satisfies the current guiding requirements between the current collecting member 130 and the first tab 121. The specific steps for carrying out this step can refer to the welding process between the current collecting member 130 and the electrode assembly 120 in the existing technology, and will not be described in detail here. S2, the cell assembly is installed into the housing 110 through the opening 112. As long as it is guaranteed that the cell assembly can be installed inside the housing 110 through the opening 112, the specific installation method of the cell assembly is not limited, and for example, it may be installed manually or by a robotic hand. S3: By extending the connection piece 132 toward the opening 112 and overlapping it at an angle with the side wall 111 of the housing 110, a welding-waiting area 180 is formed between the connection piece 132 and the side wall 111, and a gap exists between the part between the welding-waiting area 180 of the connection piece 132 and the current collecting body 131 and the side wall 111. The connecting piece 132 is located on the side of the current collecting body 131 away from the electrode assembly 120, and an inclined overlap is formed between the connecting piece 132 and the side wall 111, thereby forming a weld-ready area 180. Along the height direction of the housing 110, the gap between the end of the connecting piece 132 closest to the current collecting body 131 and the side wall 111 is maximum, and the gap between the end of the connecting piece 132 farther from the current collecting body 131 and the side wall 111 is minimum, approaching zero. The specific location of the weld-ready area 180 is not limited, as long as the area that satisfies the weld gap requirement between the connecting piece 132 and the side wall 111 is defined as the weld-ready area 180. This configuration ensures that there is a gap between the portion of the connecting piece 132 between the weld-ready area 180 and the current collecting body 131 and the side wall 111, thereby achieving no contact with the side wall 111. S4: The welding waiting area 180 is welded to form the welded portion 140 between the connection piece 132 and the side wall 111. When welding the welding waiting area 180, the welding may be performed inside the housing 110 or outside the housing 110, as long as a weld 140 that meets the strength requirements can be formed between the connecting piece 132 and the side wall 111. S5: Form a roll groove 113 by performing roll pressing on the area of ​​the side wall 111 corresponding to the weld 140, and the roll groove 113 limits the axial displacement of the electrode assembly 120. The method of forming the roll groove 113 is not limited, and may be, for example, formed by performing roll grooving processing on the side wall 111 using a roll grooving cutting tool, or the side wall 111 may be press-formed using a forming die. The cross-sectional shape of the roll groove 113 may be any shape that meets usage requirements, such as rectangular, square, or trapezoid, and the present invention is not limited thereto. S6: The end cap 150 is attached to seal the opening 112.

[0069] Referring to FIG. 1 , the outer peripheral edge of the end cap 150 is overlapped and connected to the surface facing the opening 112 of the roll groove 113 by a seal ring 170, which then seals the area of ​​the opening 112 in the side wall 111, thereby sealing the end cap 150 at the position of the opening 112 in the housing 110.

[0070] In the manufacturing steps for the cylindrical battery 100 described above, the connecting piece 132 and the side wall 111 are overlapped at an angle before the roll grooving process, so that a gap is formed between the side wall 111 and the portion of the connecting piece 132 located between the current collecting body 131 and the overlapping connection position, and the gap gradually increases along the height direction of the casing 110 from the side of the opening 112 toward the side of the electrode assembly 120. On the one hand, the presence of this gap facilitates insertion of the current collecting member 130 into the casing, and can improve the assembly efficiency and accuracy of the cylindrical battery 100. On the other hand, when roll grooving is performed at the position of the opening 112 of the housing 110, the portion between the welding portion 140 of the connection piece 132 and the current collecting body 131 is not subjected to the extrusion pressure of the side wall 111 at the corresponding position, which reduces the possibility of the connection piece 132 being displaced relative to the roll groove 113 of the welding portion 140, effectively increasing the stability of the welding between the connection piece 132 and the roll groove 113, and improving the assembly yield rate of the cylindrical battery 100.

[0071] Referring to FIG. 17 , which shows a partial view of the overlapping position between the connection piece 132 and the side wall of one embodiment of a cylindrical battery of the present invention before roll grooving, in one example of a manufacturing method of the present invention, before welding the weld-waiting area 180, the inclination angle between the connection piece 132 and the housing 110 is β, and the angle range of β is 1° to 4°, such as 1°, 2°, 3°, or 4°. Setting the inclination angle β within the range of 1° to 4° can ensure smooth insertion of the cell assembly into the housing. Furthermore, an attachment gap that meets welding requirements can be obtained between the connection piece 132 and the side wall 111, thereby meeting welding quality requirements between the connection piece 132 and the side wall 111.

[0072] In one example of the manufacturing method of the present invention, as shown in FIG. 17 , before welding the weld-waiting region 180, the distance A from the contact end of the connecting piece 132 with the side wall 111 to the contact end of the connecting piece 132 with the current collecting body 131 along the extension direction of the connecting piece 132 is 2 mm≦A≦4 mm. For example, the size A may be 2 mm, 3 mm, or 4 mm. Assuming that the inclination angle β is constant, the size A directly affects the welding position between the connecting piece 132 and the side wall 111. As the size A increases, the weld 140 formed between the connecting piece 132 and the side wall 111 approaches the opening 112, which narrows the range of sizes that can be manipulated during roll grooving and makes roll grooving inconvenient. Conversely, the closer the weld 140 formed between the connecting piece 132 and the side wall 111 is to the electrode assembly 120, the more likely it is to interfere with the welding posture of the welding head 160, making it inconvenient for the welding head 160 to weld, and making it difficult to ensure welding quality. In this embodiment, by limiting the size A to the range of 2 mm to 4 mm, it is possible to simultaneously achieve both the forming efficiency of the roll groove 113 and the welding quality of the weld 140.

[0073] 17, which is a partial view of the overlapping portion between the connecting piece 132 and the side wall 111 before roll grooving in one embodiment of a cylindrical battery of the present invention. As can be seen from FIG. 17, when welding the overlapping portion between the edge of the connecting piece 132 away from the current collecting member 130 and the inner wall of the side wall 111, a butt weld is used. Therefore, the weld pool formed at this position is shallow, and there is insufficient molten metal to fill the weld pool. This reduces the strength of the weld 140, and can easily lead to the connecting piece 132 falling off the side wall 111 during the roll grooving process. At the same time, undercuts are likely to occur, resulting in poor appearance of the welded product. In light of this, referring to FIG. 17, which is a partial view of the overlapping portion between the connecting piece 132 and the side wall 111 before roll grooving in one embodiment of a cylindrical battery of the present invention, in one example of a manufacturing method of the present invention, a weld-waiting area 180 is provided along the height direction of the side wall 111 below the intersection M formed by the contact between the connecting piece 132 and the side wall 111. The weld-waiting area 180 includes an upper edge 181 closer to the opening 112. One end of the upper edge 181 intersects with the inner wall of the side wall 111 to form an intersection S, and the other end of the upper edge 181 intersects with the connecting piece 132 to form an intersection J. The distance from the weld-waiting area 180 to the end wall of the connecting piece 132 along the extension direction of the connecting piece 132 is 0.2 mm or more. As shown in FIG. 17 , the length D of the line MJ is the distance from the weld-waiting area 180 to the end wall of the connecting piece 132, i.e., D≧0.2 mm. This configuration ensures that the weld 140 formed in the weld-waiting area 180 avoids the position where the connecting piece 132 and the side wall 111 come into contact with each other, reducing problems such as undercuts and spatters that occur due to a small gap between the connecting piece 132 and the side wall 111. This not only ensures the weld strength of the weld 140 but also improves the aesthetic appearance of the housing 110.

[0074] In one example of the manufacturing method of the present invention, refer to FIG. 17, which is a partial view of the overlap position between the connection piece 132 and the side wall 111 before roll grooving in one embodiment of a cylindrical battery of the present invention. At a position corresponding to the lower edge 182 of the welding-waiting area 180 (indicated by line KN in FIG. 17), the distance between the connection piece 132 and the side wall 111 along the radial direction of the housing 110 is 0.05 mm or less. As can be seen from FIG. 17, the overlap between the connection piece and the side wall is inclined, so at the lower edge of the welding-waiting area 180, the gap between the connection piece and the side wall is maximum, as indicated by size B in FIG. 17. Therefore, as long as size B is ensured to be 0.05 mm or less, the distance between the connection piece and the side wall within the entire welding-waiting area can be ensured to be 0.05 mm or less. If size B is smaller, the weld quality of the weld 140 will be better, but the welding process window will be smaller and the welding efficiency will be lower. Conversely, if the size of the safety gap B is large, the weld strength of the welded portion 140 will be poor, but the welding process window will be large and the welding efficiency will be high. In this embodiment, through repeated experiments, it has been found that when the size B is 0.05 mm, excellent weld strength can be obtained between the connecting piece 132 and the side wall 111, a favorable welding process window can be obtained, and the welding efficiency can be guaranteed.

[0075] 17 is a partial view of the overlapping position between the connection piece and the side wall before roll grooving in one embodiment of the cylindrical battery of the present invention, and FIG. 18 is a view of the welding-waiting area between the connection piece and the side wall before roll grooving in one embodiment of the cylindrical battery of the present invention. The distance C along the axial direction of the housing 110 between the lower edge 182 of the welding-waiting area 180 and the point M where the connection piece 132 contacts the side wall 111 is C, and C = 0.05 / tan β. From FIG. 17, it can be seen that the larger the inclination angle β between the connection piece and the side wall, the larger the size Δ. This reduces the likelihood of scratches or snagging between the connection piece and the side wall during the insertion process of the current collecting member into the housing, but reduces the contact force between the connection piece and the side wall, resulting in poor radial positioning accuracy between the current collecting member and the side wall. Conversely, a smaller size Δ increases the likelihood of scratches or snagging between the current collecting member and the side wall during insertion into the housing, but also increases the contact force between the connecting piece and the side wall, resulting in better radial positioning accuracy between the current collecting member and the side wall. In consideration of this, the inventors conducted multiple tests in actual production processes and found that setting the included inclination angle β between 1° and 4° facilitates insertion of the current collecting member into the housing and provides excellent positioning accuracy between the current collecting member and the side wall. Because the included inclination angle β may be subject to errors during the manufacturing or assembly process, the included inclination angle β of an actual product may be any value within the range of 1° to 4°, such as 1°, 2°, or 3°. In practical design, the upper limit and lower limit of the included inclination angle β are 1° and 4°, respectively. Therefore, in this embodiment, setting C to 0.05 / sin4 ensures that all values ​​of the included inclination angle β between 1° and 4° can uniformly meet the welding requirements. Setting the size C facilitates positioning of the welding head 160 in the axial direction of the housing 110 relative to the side wall 111 and the connecting piece 132 during welding.

[0076] In one example of the manufacturing method of the present invention, referring to FIG. 15, which is a diagram showing the welding position between the welding head and the connection piece of one embodiment of the cylindrical battery of the present invention, and FIG. 18, which is a diagram showing the distribution of the welding waiting area 180 between the connection piece and the side wall before roll grooving of one embodiment of the cylindrical battery of the present invention, welding is performed using laser welding equipment. The laser welding equipment includes a welding head 160. A laser beam generated by the welding head 160 is emitted from inside the housing 110 to the welding waiting area 180, and the laser beam is inclined relative to the side wall 111 to perform the welding operation. It should be noted that during the welding operation, the welding head 160 may be located either outside or inside the housing, as long as it is possible to ensure that the laser beam generated by the welding head 160 can be emitted from inside the housing 110 to the welding waiting area 180. This configuration allows an inclined molten pool 141 to be formed in the weld 140. On the one hand, the provision of the inclined weld pool 141 reduces stress concentration that occurs on the side of the weld pool 141 near the first bend 1323 during roll grooving, thereby increasing the connection strength of the weld 140 and reducing the possibility that the weld 140 will lose its effectiveness and the connection piece 132 will fall off the side wall 111. In addition, when welding the connection piece 132 and the side wall 111, the effective depth of the weld pool 141 increases, widening the welding process window of the weld 140 and making it easier to control the quality of the weld between the connection piece 132 and the side wall 111.

[0077] Furthermore, in one example of the manufacturing method of the present invention, referring to FIG. 19, which is a diagram of the welding position between the welding head and the side wall of one embodiment of the cylindrical battery of the present invention before roll grooving, the inclination angle γ between the laser beam generated by the welding head 160 and the side wall 111 is in the range of 15° to 80°. For example, γ may be 15°, 30°, 60°, or 80°. Limiting the inclination angle γ within the range of 15° to 80° can ensure that the weld 140 has excellent weld strength and can also ensure an excellent welding posture between the welding head 160 and the side wall 111, making it convenient for the welding head 160 to weld the weld, and ensuring welding efficiency and welding quality.

[0078] In the cylindrical battery of the present invention, the portion between the weld of the connecting piece and the current collecting body does not contact the side wall. When roll grooving is performed at the opening position of the housing, the portion between the weld of the connecting piece and the current collecting body is not subjected to the extrusion pressure of the side wall at the corresponding position, reducing the possibility of the connecting piece being displaced relative to the wall of the roll groove at the weld position, effectively improving the stability of the weld between the connecting piece and the roll groove, ultimately improving the stability of the electrical connection between the electrode assembly and the housing and increasing the yield of cylindrical batteries. Furthermore, after bending, the portion of the connecting piece far from the current collecting body contacts the roll groove to form a weld. After bending, the portion of the connecting piece located between the weld and the current collecting body does not contact the side wall, forming a gap. When the current collecting member is inserted into the housing before roll grooving, a gap is formed between the outer peripheral edge of the end of the connecting piece close to the electrode assembly and the inner surface of the side wall, ensuring that the end of the connecting piece far from the electrode assembly can overlap the side wall. This allows for an inclined overlapping relationship between the connecting piece and the side wall. This not only facilitates the insertion of the current collecting member into the housing, but also allows a welded portion with a large cross-sectional area to be formed between the connecting piece and the side wall, thereby increasing the welding strength between the connecting piece and the side wall. Therefore, the present invention effectively overcomes some practical problems in the existing technology, and has high applicability and practical significance.

[0079] The above-described embodiments are illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Those skilled in the art may change or modify the above-described embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent changes or modifications made by those skilled in the art without departing from the spirit and technical ideas disclosed by the present invention should still be protected by the claims of the present invention. [Industrial Applicability]

[0080] The cylindrical battery, electronic device, and method for manufacturing the cylindrical battery of the present invention are applicable to the battery technology field. [Explanation of symbols]

[0081] 100: Cylindrical battery 110: Housing 111: Side wall 112:Aperture 113: Roll Groove 1131: 1st group wall 114: End wall 115: Main body 116: Transition 117: Stretching part 118: Connection 120: Electrode assembly 121: First tab 122: Second tab 130: Current collecting member 131: Current collector body 132: Connection piece 1321: First connection 1322: Second connection part 1323: 1st bending part 1324: 1st fragile structure 1325:Second bending part 1326:Second fragile structure 1327: Thinned area 1328: Openwork area 140: Welded section 141: Molten pool 1411: Contour 150: End cap 160: Welding head 170: Seal ring 180: Welding waiting area 181: Upper edge 182: Lower edge 200: Battery assembly 210: Box body 220: Lid 300:Electronic equipment 310: Operating unit 400: Cylindrical tool

Claims

1. a housing including a sidewall having an opening formed at one end; an electrode assembly provided within the housing; Current collecting member and Including, a roll groove recessed into the housing at a position close to the opening of the side wall, the roll groove limiting displacement of the electrode assembly in the axial direction of the housing; the current collecting member is at least partially disposed between the electrode assembly and the roll groove; The current collecting member includes a current collecting body and a connecting piece connected to the periphery of the current collecting body, the current collecting body is electrically connected to the electrode assembly, the connecting piece is bent toward the axis of the housing and welded to a surface of the roll groove facing the electrode assembly to form a weld, and a gap exists between the side wall and a portion of the connecting piece between the weld and the periphery of the current collecting body. A cylindrical battery.

2. There is no contact between the side wall and the portion of the connecting piece between the welded portion and the current collecting body.

2. The cylindrical battery according to claim 1 .

3. The entire portion of the connecting piece between the welding portion and the current collecting body along the circumferential direction of the side wall does not come into contact with the side wall.

2. The cylindrical battery according to claim 1 .

4. The current collecting member includes a plurality of the connection pieces, and the plurality of connection pieces are provided so as to surround the periphery of the current collecting body.

3. The cylindrical battery according to claim 2.

5. the connection piece includes a first connection portion and a second connection portion that are connected to each other, the first connection portion being a portion located between the welded portion and the current collecting body, and the second connection portion extending from one end of the first connection portion that is close to the welded portion into the interior of the housing; The first connecting portion is bent relative to the second connecting portion to form a first bent portion.

3. The cylindrical battery according to claim 2.

6. The thickness of the connecting piece is 0.1 to 0.3 mm.

6. The cylindrical battery according to claim 5,

7. The first bent portion extends along a circumferential direction of the side wall, and a first weakened structure is provided in the first bent portion.

6. The cylindrical battery according to claim 5.

8. The first weakened structure includes a thinned region provided in the first bend portion.

8. The cylindrical battery according to claim 7.

9. The first weakened structure includes an openwork region provided in the first bent portion.

8. The cylindrical battery according to claim 7.

10. The first connection portion is bent toward the center of the current collecting body to form a second bent portion.

6. The cylindrical battery according to claim 5.

11. The second bend portion is provided with a second weakened structure.

11. The cylindrical battery according to claim 10.

12. The developed length size from one end of the connecting piece connected to the current collecting body to the free end of the connecting piece is A, the minimum distance between the second bent portion and the side wall is Δ, the length of the second connecting portion is F, and the width size of the welding portion along the extension direction of the second connecting portion is W, and 0.2 mm + W≦F≦(0.05 mm×A) / Δ is satisfied.

11. The cylindrical battery according to claim 10.

13. The length of the second connection portion is F, and the width of the welded portion along the extension direction of the second connection portion is W, where W≦F≦0.05 mm / sin4.

11. The cylindrical battery according to claim 10.

14. The roll groove includes a first group wall on a side facing the electrode assembly, and the weld portion includes a molten pool. In an axial cross section of the cylindrical battery passing through the molten pool, a side of a contour line of the molten pool farther from the axis of the housing intersects with the first group wall to form a first intersection point. An obtuse angle θ away from the axis of the housing is formed between the first group wall and a tangent to the contour line passing through the first intersection point.

2. The cylindrical battery according to claim 1 .

15. At least a part of a central region of the current collecting body protrudes toward the opening along the axial direction of the housing and is higher than a peripheral region of the current collecting body covered by the roll grooves.

2. The cylindrical battery according to claim 1 .

16. The cylindrical battery according to any one of claims 1 to 15. An electronic device comprising:

17. A method for manufacturing a cylindrical battery, the cylindrical battery including a housing, an electrode assembly, a current collecting member, and an end cap, the housing including a side wall having an opening formed at one end of the side wall, the current collecting member including a current collecting body and a connecting piece fixedly connected to a periphery of the current collecting body, welding the current collecting body of the current collecting member to a tab of the electrode assembly to form a cell assembly; installing the cell assembly into the housing through the opening; the connecting piece is extended toward the opening side and overlapped at an angle with the side wall of the housing to form a welding-ready region between the connecting piece and the side wall, and a gap exists between the side wall and a portion of the connecting piece between the welding-ready region and the current collecting body; welding the welding-waiting region to form a weld between the connection piece and the side wall; a roll groove formed by roll pressing the side wall area corresponding to the weld, and restricting axial displacement of the electrode assembly by the roll groove; attaching the end cap to the opening; A manufacturing method comprising:

18. Before welding the welding waiting area, the inclination angle between the connection piece and the housing is set to β, and the angle range of β is set to 1° to 4°.

18. The method of claim 17.

19. Before welding the welding-waiting region, the dimension from the contact end of the connection piece with the side wall to the connection end of the connection piece with the current collecting body is defined as A, and 2 mm≦A≦4 mm, along the extension direction of the connection piece.

18. The method of claim 17.

20. The distance from the welding-waiting region to the end wall of the connecting piece along the extending direction of the connecting piece is 0.2 mm or more.

18. The method of claim 17.

21. The distance between the connection piece and the side wall in the waiting-for-weld region along the radial direction of the housing is 0.05 mm or less.

21. The method of claim 20.

22. When welding the welding-ready area, laser welding is used, and a laser beam generated by a welding head is emitted from inside the housing to the welding-ready area, and welding is performed in a position inclined relative to the side wall.

18. The method of claim 17.

23. The included angle γ between the laser beam generated by the welding head and the side wall is in the range of 15° to 80°.

23. The method of claim 22.

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