Laminated bending structure and manufacturing method thereof, confluence plate and cylindrical battery

Abstract

The invention relates to a laminated bending structure and a manufacturing method thereof, a confluence plate and a cylindrical battery, the laminated bending structure comprises m laminated film layers, the m film layers jointly form a first fixed section, a bending section and a second fixed section which are connected in sequence, the m film layers of the first fixed section and the second fixed section are relatively fixed, the m film layers of the bending section can move relatively, and the m film layers of the bending section can move relatively. In the bending state of the laminated bending structure, the bending section comprises a bending inner side and a bending outer side which are opposite to each other, the bending outer side is the outer surface of the laminated bending structure, in the direction from the bending inner side to the bending outer side, the length of the n film layer is smaller than that of the (n + 1) film layer, the (n + 1) film layer is closer to the bending outer side than the n film layer, m and n are positive integers, and m is larger than n. According to the laminated bending structure, the internal compression stress during bending of the multiple film layers can be fundamentally eliminated, inner layer wrinkling and stress concentration are avoided, the anti-fatigue performance of the structure under repeated bending is greatly improved, and the service life is remarkably prolonged.

Description

Technical Field

[0001] This invention relates to the field of bending materials technology, specifically to a stacked bending structure and its manufacturing method, a busbar, and a cylindrical battery. Background Technology

[0002] In fields such as flexible circuits, energy storage batteries, and medical devices, bendable structures are increasingly widely used because they can overcome the form limitations of traditional rigid structures and meet the needs of portable and versatile devices. For example, the structure connecting conductors in batteries, the folding screen support structure of flexible mobile phones, the flexible connection components of wearable devices, and the bending guide structure of medical catheters all rely on bendable designs to achieve their core functions.

[0003] Current mainstream bendable structures still have significant technical shortcomings in practical applications. When bending, due to the bending direction, a smaller inner bending radius and a larger outer bending radius are formed. The inner material is compressed, while the outer material is stretched. In structures of equal length, the inner material cannot shrink freely, resulting in compressive stress. This causes the inner foil to wrinkle, bulge, or be squeezed into the bending ring. Furthermore, the outer material experiences more concentrated stress, leading to cracking, breakage, or plastic deformation, ultimately causing structural failure. Summary of the Invention

[0004] The purpose of this invention is to provide a stacked bending structure and its manufacturing method, a busbar, and a cylindrical battery. This stacked bending structure can avoid the stress concentration problem caused by bending.

[0005] In a first aspect, the present invention provides a stacked bending structure comprising m layers of film, the m layers of film forming a first fixed segment, a bending segment, and a second fixed segment connected in sequence, wherein the m layers of film in the first fixed segment and the second fixed segment are relatively fixed, and the m layers of film in the bending segment are relatively movable; the stacked bending structure includes an unfolded state and a bent state, wherein in the unfolded state, the first fixed segment and the second fixed segment are separated; and in the bent state, the bending segment includes an inner bending side and an outer bending side facing away from each other, wherein the outer bending side is the outer surface of the stacked bending structure, and in the direction from the inner bending side to the outer bending side, the length of the nth layer of film is less than the length of the (n+1)th layer of film, and the (n+1)th layer of film is closer to the outer bending side than the nth layer of film, wherein m and n are both positive integers, and m is greater than n.

[0006] In some embodiments, in the bent state, the length of the m layers of the film increases at an equal gradient along the direction from the inside of the bend to the outside of the bend.

[0007] In some embodiments, in the bent state, the first fixed segment and the second fixed segment are connected, the bent segment is bent along the thickness direction of the film layer in the first fixed segment, and the thickness of the bent segment after bending is equal to the sum of the thicknesses of the first fixed segment and the second fixed segment.

[0008] In some embodiments, in the unfolded state, the bent section has a groove, and the depth R2 of the groove satisfies: 0mm < R2 ≤ 1mm.

[0009] In a second aspect, the present invention provides a method for manufacturing a laminated bending structure, the method being used to manufacture the laminated bending structure as described in the first aspect, the method comprising: stacking m layers of film to obtain a workpiece to be processed; pressing the workpiece to be processed with a push rod to form a bending segment on the workpiece to be processed; hot pressing or rolling the workpiece to be processed having the bending segment to form a first fixed segment and a second fixed segment at opposite ends of the bending segment, thereby obtaining the laminated bending structure.

[0010] In some embodiments, the end of the push rod pressing against the workpiece is an arc-shaped structure with a radius of R1; in the unfolded state, the push rod presses against the workpiece to deform and form a groove, the maximum depth of the groove in the axial direction of the push rod is R2, the thickness of the m layers is k, and the manufacturing method satisfies: R1≤R2+k.

[0011] Thirdly, the present invention provides a busbar including a stacked bending structure as described in the first aspect, wherein the stacked bending structure is conductive.

[0012] In some embodiments, the manifold includes a contact section connected to the first fixed section, the area of ​​the contact section being larger than the area of ​​the first fixed section.

[0013] In some embodiments, the contact segment includes an edge whose orthographic projection on the stacked bending structure lies between the bending segment and the first fixing segment, and the orthographic projection of the contact segment covers the first fixing segment.

[0014] In some embodiments, there are multiple stacked bending structures, which are connected sequentially. In the unfolded state, in two adjacent stacked bending structures, the first fixed segment of the preceding stacked bending structure is connected to the second fixed segment of the following stacked bending structure.

[0015] In some embodiments, the plurality of the stacked bending structures include a first stacked bending structure and a second stacked bending structure, wherein the number of film layers in the first stacked bending structure and the second stacked bending structure is the same, and the m film layers in the first stacked bending structure and the second stacked bending structure are connected in a one-to-one correspondence.

[0016] Fourthly, the present invention provides a cylindrical battery, including tabs and a busbar as described in the third aspect.

[0017] The laminated bending structure provided by this invention, by setting the bending section as a movable multilayer film layer with different film layers, can fundamentally eliminate the internal compressive stress during bending of the multilayer film layer, avoid wrinkling of the inner layer and stress concentration, and greatly improve the fatigue resistance of the structure under repeated bending, thus significantly extending its service life. Furthermore, the bending section uses the same film layer as the first fixed section and the second fixed section, which allows each film layer to maintain good electrical and mechanical connection in the fixed section, and the conductivity and mechanical strength are not affected. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a stacked bending structure in its unfolded state according to one implementation method; Figure 2 This is a schematic diagram of a laminated bending structure in a bending state according to one embodiment; Figure 3 This is a schematic diagram illustrating the disassembly of a busbar structure in one implementation method; Figure 4 This is a schematic diagram of a busbar in its deployed state according to one implementation method; Figure 5 This is a schematic diagram of a busbar in a folded state according to one implementation method; Figure 6 This is the process of manufacturing the bent segment of a laminated bending structure as one implementation method; Figure 7 This is a flowchart illustrating the fabrication process of a layered bending structure as one implementation method.

[0020] Explanation of reference numerals in the attached figures: 10-Layered bending structure, 11-Membrane layer, 111-First fixed section, 112-Bending section, 112A-Inner bending side, 112B-Outer bending side, 113-Second fixed section, 114-Contact section, 114A-Edge, 101-First layered bending structure, 102-Second layered bending structure, 20-Manifold, 30-Top rod. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] It should be noted that when a component is said to be "fixed" to another component, it can be directly on the other component or it can be in a middle component. When a component is said to be "connected" to another component, it can be directly connected to the other component or it may be in a middle component.

[0023] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0024] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0025] In fields such as flexible circuits, energy storage batteries, and medical devices, bendable structures are increasingly widely used because they can overcome the form limitations of traditional rigid structures and meet the needs of portable and versatile devices. For example, the structure connecting conductors in batteries, the folding screen support structure of flexible mobile phones, the flexible connection components of wearable devices, and the bending guide structure of medical catheters all rely on bendable designs to achieve their core functions.

[0026] Current mainstream bendable structures still have significant technical shortcomings in practical applications. During bending, due to the bending direction, a smaller inner bending radius and a larger outer bending radius are formed, resulting in compression of the inner material and stretching of the outer material. In equal-length structures, the inner material cannot freely contract, leading to compressive stress. This causes wrinkling, bulging, or compression of the inner foil layer into the bending ring, while the outer material experiences more concentrated stress, leading to cracking, breakage, or plastic deformation, ultimately causing structural failure. Therefore, this invention provides a layered bending structure that balances the pressure on the inner and outer sides after bending, thus avoiding uneven stress distribution. This layered bending structure is applicable to numerous fields such as FPCs, battery busbars, wearable device hinges, and medical catheters, possessing high versatility.

[0027] For some implementation methods, please refer to Figure 1 and Figure 2 The stacked bending structure 10 includes stacked m layers of film 11, which together form a first fixed segment 111, a bending segment 112, and a second fixed segment 113 connected in sequence. The m layers of film 11 in the first fixed segment 111 and the second fixed segment 113 are relatively fixed, while the m layers of film 11 in the bending segment 112 are relatively movable. The stacked bending structure 10 includes an unfolded state and a bent state. In the unfolded state, the first fixed segment 111 and the second fixed segment 112 are relatively fixed. 3. Separation; In the bent state, the bent segment 112 includes an inner bent side 112A and an outer bent side 112B facing away from each other. The outer bent side 112B is the outer surface of the stacked bent structure 10. Along the direction from the inner bent side 112A to the outer bent side 112B, the length of the nth film layer 11 is less than the length of the (n+1)th film layer. The (n+1)th film layer 11 is closer to the outer bent side 112B than the nth film layer. m and n are both positive integers, and m is greater than n.

[0028] In a specific embodiment, the film layer 11 is a thin sheet structure, and the material of the film layer 11 can be metal or polymer, etc., wherein the metal film layer 11 can be copper foil, aluminum foil, gold foil, tin foil, zinc foil, etc.; the polymer film layer 11 can be polyimide foil (PI foil), polyester foil (PET foil), polytetrafluoroethylene foil (PTFE foil), etc. Preferably, the film layer 11 can be a metal foil material, the film layer 11 is conductive, and the thickness of the film layer 11 can be 0.001mm-0.2mm; the stacked bending structure 10 can be applied in the battery as a busbar 20.

[0029] In a specific embodiment, the number of membrane layers 11 is multiple (m layers), where m is a natural number greater than 2. The m membrane layers 11 are stacked to form a composite structure. Optionally, the shapes and thicknesses of the multiple membrane layers 11 can be the same or different; the materials of the multiple membrane materials can be the same or different. Preferably, the thickness and material of the multiple membrane layers 11 are the same, and the shape of the membrane layers 11 can be rectangular. Therefore, the membrane layer 11 can include a length direction, a width direction, and a thickness direction, wherein the dimension in the length direction is greater than the dimension in the width direction, and the thickness direction is the stacking direction of the membrane layers 11.

[0030] In a specific embodiment, along the length of the film layer 11, the laminated bending structure 10 includes a first fixed segment 111, a bending segment 112, and a second fixed segment 113 connected sequentially. It should be noted that each film layer 11 can be a single, integral structure, so there is no clear connection boundary between the first fixed segment 111, the bending segment 112, and the second fixed segment 113. However, in the laminated bending structure 10, each film layer 11 in the first fixed segment 111 and the second fixed segment 113 is fixed to each other, while each film layer 11 in the bending segment 112 is not fixed. Therefore, it can be understood that both ends of the bending segment 112 (the first fixed segment 111 and the second fixed segment 113) are fixed.

[0031] In a specific embodiment, in the first fixed section 111 and the second fixed section 113, each film layer 11 is fixed by means including but not limited to calendering, laser welding, ultrasonic welding, or conductive adhesive bonding. In the bending section 112, each film layer 11 is not fixed by the above processes, thereby ensuring that each film layer 11 in the bending section 112 can deform freely and without stress.

[0032] In a specific embodiment, both ends of the bent segment 112 are fixed, and the length of each film layer 11 in the bent segment 112 may be different. It should be noted that the length of the film layer 11 refers to the dimension of the film layer 11 along the length direction. Specifically, along the thickness direction, the length of the previous film layer 11 (or the next film layer 11) may be greater than the length of the next film layer 11 (or the previous film layer 11). At the same time, after the stacked bending structure 10 is bent, the shorter film layer 11 is located on the inside of the bend, and the longer film layer 11 is located on the outside of the bend.

[0033] In a specific embodiment, the laminated bending structure 10 can be prepared by first precisely cutting film layers 11 (foil) of different lengths. The film layers 11 have the same thickness and material, and the same width but different lengths. Then, a high-precision fixture is used to stack the film layers 11 in order of length, and the two ends of each film layer 11 are aligned in the length direction so that the longer film layer 11 has a partial bulge in the middle. Finally, welding or bonding is performed at the designated non-bending fixing points (first fixing segment 111 and second fixing segment 113) to form an integrated laminated bending structure 10.

[0034] The laminated bending structure 10 provided by the present invention, by setting the bending section 112 as a movable multilayer film layer 11 and setting the length of the film layer 11 to be different, can fundamentally eliminate the internal compressive stress when the multilayer film layer 11 is bent, avoid wrinkling of the inner layer and stress concentration, so that the fatigue resistance of the structure under repeated bending is greatly improved and the service life is significantly extended. Furthermore, the bending section 112 uses the same film layer 11 as the first fixed section 111 and the second fixed section 113, which can ensure that each film layer 11 maintains good electrical and mechanical connection in the fixed section, and the conductivity and mechanical strength are not affected.

[0035] For some implementation methods, please refer to Figure 1 and Figure 2 In the bent state, along the direction from the inner side 112A to the outer side 112B of the bend, the length of the m-layer film 11 increases at a constant gradient. Specifically, the stacking direction is the thickness direction mentioned above, and the length of the m-layer film 11 increases (or decreases) in an arithmetic sequence; that is, the length difference between any two adjacent film layers 11 is the same.

[0036] By setting the length of the m-layer membrane 11 to increase at an equal gradient, each membrane layer is in its neutral layer position when bent. This not only makes the stress distribution of the two adjacent membrane layers uniform and avoids sudden changes in local stress, but also minimizes the size of the bent section 112 after bending and compresses the space occupied by the stacked bending structure 10 after bending.

[0037] For some implementation methods, please refer to Figure 1 and Figure 2 In the bent state, the first fixed segment 111 and the second fixed segment 113 are connected, and the bent segment 112 is bent. Along the thickness direction of the film layer 11 in the first fixed segment 111, the thickness of the bent segment 112 after bending is equal to the sum of the thicknesses of the first fixed segment 111 and the second fixed segment 113.

[0038] In specific implementation, the unfolded state refers to the state of the stacked bending structure 10 after unfolding. The unfolded state can be selected as the state in which the first fixed segment 111 and the second fixed segment 113 are on the same plane (e.g., Figure 1(As shown); the bent state refers to the state of the laminated bent structure 10 after bending. The bent state can be selected as the laminated bent structure 10 being folded in half, with the orthographic projections of the first fixed segment 111 and the second fixed segment 113 in the thickness direction at least partially overlapping (e.g., Figure 2 (As shown).

[0039] In a specific embodiment, in the bent state, the stacked bent structure 10 has a uniform thickness, that is, the thickness of the bent segment 112 after bending is equal to the sum of the thicknesses of the first fixed segment 111 and the second fixed segment 113. It can be understood that the thickness of the bent segment 112 after bending is 2×m×t, where t is the thickness of the single-layer film 11.

[0040] For some implementation methods, please refer to Figure 6 In the unfolded state, the bent segment 112 has a groove, and the depth R2 of the groove satisfies: 0mm < R2 ≤ 1mm. Optionally, the depth R2 of the groove can be 0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, or 0.1mm. It should be noted that the groove serves as a reference for the bending mark of the bent segment 112. The groove depth meeting this range ensures a small R-angle after bending, and the recommended height after bending is...

[0041] On the other hand, cylindrical batteries typically have a busbar 20 at the end of the core to connect the busbar 20 to the positive (or negative) electrode of the core. However, existing cylindrical battery busbars 20 (especially those with a square sheet + circular sheet structure) are mostly formed by stamping from a single piece of metal. At the bends, the bending angle is large, the material thins at the bends, and there is significant residual stress, making them prone to fatigue cracking under long-term vibration, leading to battery failure. Furthermore, it increases the bending height, reducing the internal height space of the battery.

[0042] Therefore, based on the features of the stacked bending structure 10 provided in the above embodiments, the present invention also provides a busbar 20, please refer to... Figures 3-5 The structure includes the laminated bending structure 10 provided in the above embodiments, and the laminated bending structure 10 is conductive. Specifically, the bending structure is applied in the busbar 20, specifically at the bending point of the busbar 20. Optionally, the busbar 20 may include multiple layers of foil, and the foil of the busbar 20 is the film layer 11 in the above embodiments.

[0043] In order to improve the reliability of the existing busbar 20, minimize the space occupied by the bending structure in the battery, and completely solve the problems of stress cracking and fatigue failure in the bending area, the present invention applies the stacked bending structure 10 in the above embodiment to the busbar 20, which can provide a thinner, more reliable, and innovative busbar 20 that can contribute to the battery with higher energy density.

[0044] This invention applies a stacked bending structure 10 to the busbar 20, which not only achieves a "zero-height" bending effect, significantly reducing the occupancy of the bending structure on the battery's internal Z-axis height, thus providing the possibility to increase the capacity of electrode materials and improve battery energy density; moreover, the busbar 20 has no internal stress at the bending point, fundamentally solving the stress cracking problem of traditional stamping bending and the bulging fracture problem of equal-length composite structures, greatly improving the battery's vibration resistance and fatigue resistance; at the same time, the multilayer film 11 provides a larger conductive cross-sectional area, reduces internal resistance, and is beneficial to the battery's fast charging and discharging performance.

[0045] For some implementation methods, please refer to Figure 3 and Figure 4 The busbar 20 includes a contact section 114 connected to a first fixed section 111. The area of ​​the contact section 114 is larger than the area of ​​the first fixed section 111. Specifically, the contact section 114 can be circular or near-circular, and can adopt a multi-layer foil lamination structure or a solid metal sheet structure. The contact section 114 is used to contact the end face of the battery core; therefore, the contact section 114 needs to provide a large lateral conductive area to ensure good welding and current collection performance with the battery core tabs, while the multi-layer lamination ensures sufficient rigidity.

[0046] In a specific embodiment, the contact segment 114 can adopt a multi-layer foil pressing structure, that is, the contact segment 114 may include multiple layers of foil. The number of foils in the contact segment 114 can be the same as the number of film layers 11 in the bending segment 112 in the above embodiment, that is, multiple foils and multiple film layers 11 are connected in a one-to-one correspondence. Preferably, the foil and film layer 11 are an integral structure, both are made of the same material, and the foil and film layer 11 are the same piece of metal foil.

[0047] In a specific embodiment, the contact segment 114 can adopt an integral metal sheet structure, that is, the contact segment 114 is a complete metal sheet, and the contact segment 114 and the first fixing segment 111 are connected and fixed by means of rolling, laser welding, ultrasonic welding or conductive adhesive bonding.

[0048] In some embodiments, the contact segment 114 includes an edge 114A. The orthographic projection of the edge 114A onto the stacked bending structure 10 lies between the bending segment 112 and the first fixed segment 111, and the orthographic projection of the contact segment 114 covers the first fixed segment 111. Specifically, the edge 114A of the contact segment 114 is a straight edge, and the width of the edge 114A is the same as the width of the bending segment 112. In this way, the edge 114A can be flush with the connection between the bending segment 112 and the first fixed segment 111. The bending segment 112 is bent near the contact segment 114, which can reduce the excess length of the first fixed segment 111 on the one hand, and avoid bending into the contact segment 114 on the other hand, thus ensuring the structural integrity of the contact segment 114.

[0049] For some implementation methods, please refer to Figure 3 The stacked bending structure 10 has multiple layers, which are connected sequentially. In the unfolded state, in two adjacent stacked bending structures 10, the first fixed segment 111 of the preceding stacked bending structure 10 is connected to the second fixed segment 113 of the following stacked bending structure 10. Specifically, the busbar 20 can be a "two-fold" structure, that is, the busbar 20 includes two stacked bending structures 10, which can be bent twice (e.g., ...). Figure 5 (As shown in A3 and A4). The first fixed segment 111 of the first stacked bending structure 10 is used to connect to the contact segment 114 mentioned above, and the second fixed segment 113 of the first stacked bending structure 10 connects to the first fixed segment 111 of the second stacked bending structure 10.

[0050] The present invention provides a busbar 20, which uses a multi-layer film layer 11 (foil) pressing structure in the fixed section of the stacked bending structure 10 to ensure the mechanical strength and flow capacity of the overall structure; moreover, the bending section 112 in the stacked bending structure 10 also adopts a gradient length multi-layer film layer 11 (foil) composite structure, which is a key area to achieve extremely small R-angle bending and stress release, so as to achieve smooth and stress-free bending at this point.

[0051] In some embodiments, the plurality of stacked bending structures 10 include a first stacked bending structure 101 and a second stacked bending structure 102. The number of film layers in the first stacked bending structure 101 and the second stacked bending structure 102 is the same, and the m film layers 11 in the first stacked bending structure 101 and the second stacked bending structure 102 are connected in a one-to-one correspondence. Specifically, the film layers 11 in the plurality of stacked bending structures 10 are connected in a one-to-one correspondence; that is, the plurality of film layers 11 continuously form the plurality of stacked bending structures 10.

[0052] In a specific embodiment, the first stacked bending structure 101 includes m layers of film 11, and the second stacked bending structure 102 includes m layers of film 11. The nth layer of film 11 in the first stacked bending structure 101 is connected to the nth layer of film 11 in the second stacked bending structure 102, and both the nth layer of film 11 in the first stacked bending structure 101 and the nth layer of film 11 in the second stacked bending structure 102 are a single metal foil. The multiple stacked bending structures 10 are integrated into a single unit, enabling reliable electrical and mechanical connections, ultimately forming a complete, integrated busbar 20.

[0053] In a specific embodiment, the busbar 20 can be manufactured by first preparing the structure of each segment separately, that is, by laminating, hot pressing or rolling through the pressing area to obtain the first fixed segment 111 and the second fixed segment 113 with the membrane layer 11 fixed, and the bending segment 112 is completed by precision cutting, stacking and fixing; then, high-precision tooling fixtures are used to position each partition structure, and each partition structure is welded into an integral busbar 20 through processes such as laser welding.

[0054] The present invention also provides a cylindrical battery, including tabs and a busbar 20 as described in the above embodiments. The busbar 20 is electrically connected to the tabs. This cylindrical battery can reduce the space occupied by the busbar 20, improve the high energy density and high reliability of the cylindrical battery, and has great commercial application value.

[0055] This invention also provides a stacked bending structure and a method for manufacturing a busbar having the same structure. Please refer to [link / reference]. Figure 6 and Figure 7 The fabrication method of the layered bending structure includes the following steps: Step S100: Stack the m layers of film to obtain the workpiece to be processed, and use a push rod to press the workpiece to form a bent section on the workpiece; Step S200: The workpiece to be processed with the bent section is hot-pressed or rolled so that the two opposite ends of the bent section form the first fixed section and the second fixed section respectively, thus obtaining the laminated bent structure.

[0056] In a specific embodiment, a positioning fixture can be used to position the multiple membrane layers during stacking to ensure that the width direction of each membrane layer is aligned and the length direction is staggered according to a preset gradient difference. Compared with the prior art, the manufacturing method provided by the present invention can be used to manufacture multi-membrane layer curved busbars without cutting the membrane layers to achieve a complete stacked bending structure, thus ensuring the integrity of the stacked bending structure.

[0057] For some implementation methods, please refer to Figure 6The top rod 30 presses against one end of the workpiece to be processed, which is an arc-shaped structure with a radius of R1. In the unfolded state, the top rod 30 presses against the workpiece to be processed to deform and form a groove. The maximum depth of the groove in the axial direction of the top rod 30 is R2. The thickness of the m film layers is k. The manufacturing method satisfies: R1≤R2+k.

[0058] In a specific embodiment, please refer to Figure 6 In A5, the radius ΦR1 of the arc-shaped structure refers to the distance from the center of the arc-shaped structure to the end of the push rod 30. The workpiece pressed by the push rod 30 is actually an unfolded, layered, bent structure. The pressing position of the push rod 30 will form an arc-shaped protrusion before bending (i.e., a concave groove). The layered, bent structure can be bent with the groove as a reference to obtain the bent layered, bent structure. To ensure that the R-angle of the bent section in the bent state is small and to ensure the usable space of the manifold, R2 can be controlled to be ≤1.0mm. At the same time, it can also ensure that the arc-shaped structure of the push rod 30 is fully attached to the membrane layer, and that each membrane layer is tightly attached together under the pressure of the push rod 30, avoiding local stress concentration during pressing.

[0059] In some embodiments, the method for manufacturing a busbar with a layered bending structure further includes: Step S300: The contact section and the first fixed section are welded together by laser welding.

[0060] In a specific embodiment, one side of the contact segment and one side of the first fixed segment are laser welded together. The edge of the contact segment is flush with the connection between the bent segment and the first fixed segment, so that the first fixed segment is completely in contact with the contact segment. This ensures that the two have a large contact area, which not only facilitates laser welding but also improves the stability after welding.

[0061] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship of the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and other indicators are based on the orientation or positional relationship of the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0062] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A layered bending structure (10), characterized in that, The device includes m layers of film (11) stacked together, which together form a first fixed segment (111), a bent segment (112), and a second fixed segment (113) connected in sequence. The m layers of film (11) in the first fixed segment (111) and the second fixed segment (113) are relatively fixed, while the m layers of film (11) in the bent segment (112) are relatively movable. The stacked bending structure (10) includes an unfolded state and a bent state. In the unfolded state, the first fixed segment (111) and the second fixed segment (113) are separated. In the bent state, the bent segment (112) includes an inner bent side (112A) and an outer bent side (112B) facing away from each other. The outer bent side (112B) is the outer surface of the stacked bending structure (10). Along the direction from the inner bent side (112A) to the outer bent side (112B), the length of the nth film layer (11) is less than the length of the (n+1)th film layer (11). The (n+1)th film layer (11) is closer to the outer bent side (112B) than the nth film layer (11). m and n are both positive integers, and m is greater than n.

2. The laminated bending structure (10) according to claim 1, characterized in that, In the bent state, the length of the m layers of the film (11) increases at an equal gradient from the inner side (112A) of the bend to the outer side (112B) of the bend.

3. The laminated bending structure (10) according to claim 1, characterized in that, In the bent state, the first fixed segment (111) and the second fixed segment (113) are connected, and the bent segment (112) is bent along the thickness direction of the film layer (11) in the first fixed segment (111). The thickness of the bent segment (112) after bending is equal to the sum of the thicknesses of the first fixed segment (111) and the second fixed segment (113).

4. The laminated bending structure (10) according to claim 1, characterized in that, In the unfolded state, the bent section (112) has a groove, and the depth R2 of the groove satisfies: 0mm < R2 ≤ 1mm.

5. A method for manufacturing a layered bending structure, characterized in that, The manufacturing method is used to manufacture the laminated bending structure (10) as described in any one of claims 1-4, and the manufacturing method includes: The m-layer film is stacked to obtain the workpiece to be processed. The workpiece is pressed with a push rod to form a bent section on the workpiece. The workpiece having the bent section is hot-pressed or rolled so that the two opposite ends of the bent section form a first fixed section and a second fixed section respectively, thus obtaining the laminated bent structure.

6. The manufacturing method according to claim 5, characterized in that, The end of the push rod that presses against the workpiece to be processed has an arc-shaped structure with a radius of R1. In the unfolded state, the push rod presses the workpiece to deform to form a groove. The maximum depth of the groove along the axial direction of the push rod is R2, and the sum of the thicknesses of the m-layer film is k. The manufacturing method satisfies: R1≤R2+k.

7. A busbar (20), characterized in that, Includes the stacked bending structure (10) as described in any one of claims 1-4, wherein the stacked bending structure (10) is conductive.

8. The busbar (20) according to claim 7, characterized in that, The manifold (20) includes a contact section (114) that connects to the first fixed section (111), and the area of ​​the contact section (114) is larger than the area of ​​the first fixed section (111).

9. The busbar (20) according to claim 8, characterized in that, In the unfolded state, the contact segment (114) includes an edge (114A), the orthographic projection of which on the stacked bending structure (10) is located between the bending segment (112) and the first fixed segment (111), and the orthographic projection of the contact segment (114) covers the first fixed segment (111).

10. The busbar (20) according to claim 7, characterized in that, The number of the stacked bending structures (10) is multiple, and the multiple stacked bending structures (10) are connected in sequence. In the unfolded state, in two adjacent stacked bending structures (10), the first fixed segment (111) of the previous stacked bending structure (10) is connected to the second fixed segment (113) of the next stacked bending structure (10).

11. The busbar (20) according to claim 10, characterized in that, The plurality of the stacked bending structures (10) include a first stacked bending structure (101) and a second stacked bending structure (102). The first stacked bending structure (101) and the second stacked bending structure (102) have the same number of film layers (11). The m film layers (11) in the first stacked bending structure (101) and the second stacked bending structure (102) are connected in a one-to-one correspondence.

12. A cylindrical battery, characterized in that, It includes a tab and a busbar (20) as described in any one of claims 7-11, the busbar (20) being electrically connected to the tab.

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