Battery cell, battery pack, and electronic device

Abstract

The application provides a battery monomer, a battery pack and an electronic device. The battery monomer comprises: a shell assembly; an electrode assembly accommodated in an accommodation space of the shell assembly; a current collector disc electrically connected between the electrode assembly and the shell assembly, and comprising a disc surface portion and a fixing portion connected to the periphery of the disc surface portion. The fixing portion comprises a connecting portion connected to the disc surface portion, a welding portion welded and fixed with the shell assembly, and a transition portion connected between the connecting portion and the welding portion, the transition portion is provided with at least one bending portion, and the thickness of the welding portion is greater than the maximum thickness of the disc surface portion. The above technical solution can at least improve the assembly accuracy of the current collector disc and the shell assembly.

Description

Technical Field

[0001] This utility model relates to a battery cell, a battery pack, and an electronic device. Background Technology

[0002] In the field of new energy power batteries, a single battery cell generally includes electrode components and a casing assembly. The electrode component comprises a positive electrode sheet, a negative electrode sheet, and a separator located between the positive and negative electrode sheets. These positive and negative electrode sheets and the separator are stacked and wound to form the electrode component. The electrode component is then connected to a current collector and encapsulated within the casing assembly. In some cases, the current collector needs to be bent before fitting with the casing assembly. However, the current collector is prone to deformation after welding to the electrode component, increasing the difficulty of assembly with the casing assembly. Utility Model Content

[0003] In view of the problems existing in the related technologies, the purpose of this utility model is to provide a battery cell, battery pack and electronic device, which can at least improve the assembly accuracy of the current collector and the housing assembly.

[0004] To achieve the above objectives, this utility model provides a battery cell comprising: a housing assembly including a housing with an opening at one end; the housing assembly further comprising a cover covering the opening and defining an accommodating space together with the housing; an electrode assembly housed within the accommodating space; and a current collector electrically connected between the electrode assembly and the housing assembly, comprising a disk surface and a fixing portion connected to the periphery of the disk surface, wherein the fixing portion comprises a connecting portion connected to the disk surface, a welding portion welded to the housing assembly, and a transition portion connecting the connecting portion and the welding portion, the transition portion having at least one bending portion, and the thickness of the welding portion being greater than the maximum thickness of the disk surface.

[0005] In some embodiments, the bend closest to the disk surface in the bend is the first bend, and the minimum thickness of the portion of the transition section located on the side of the first bend closest to the weld is greater than the maximum thickness of the disk surface.

[0006] In some embodiments, the bending portion further includes a second bending portion near the welding portion, a first bending connection segment is provided between the first bending portion and the second bending portion, and a second bending connection segment is provided between the second bending portion and the welding portion, wherein at least one of the thickness of the first bending connection segment and the thickness of the second bending connection segment is greater than the maximum thickness of the disk surface.

[0007] In some embodiments, the transition portion further includes a third bent connecting segment located between the first bent connecting segment and the second bent portion, the third bent connecting segment being arranged parallel to the second bent connecting segment and stacked along the axial direction of the electrode assembly.

[0008] In some embodiments, the disk surface and the fixing part are separate structures that are fixedly connected to each other. The bending part includes a first bending part near the disk surface, and the connecting part is located between the first bending part and the disk surface and is fixedly connected to the disk surface. In some embodiments, the current collector includes at least two fixing parts, which are spaced apart and uniformly positioned circumferentially on the disk surface, and the connecting parts are respectively fixedly connected to the disk surface. In some embodiments, the electrode assembly includes a tab that is welded and fixed to the current collector. The current collector and the tab of the electrode assembly are welded together to form a tab welding part, which is located on the disk surface and / or the connecting part. In some embodiments, the substrate of the disk surface is different from the substrate of the fixing part, and / or the hardness difference between the disk surface and the fixing part is at least 10 HV.

[0009] In some embodiments, the collector plate has at least one opening structure on its surface, and the opening structure is not provided at the connection portion. In some embodiments, the total area of ​​the at least one opening structure is S1, and the area of ​​the collector plate defined by the boundary of the connection portion away from the surface of the plate is S2, wherein S1 ranges from 0.5%×S2 to 85%×S2, or from 10%×S2 to 50%×S2.

[0010] In some embodiments, at least one of the following is satisfied: the electrode assembly includes a tab welded to the collector plate, and a plating layer is provided on the surface of the plate portion welded to the tab portion; a plating layer is provided on the surface of the fixing portion welded to the housing assembly; and a plating layer is provided on the surface of the housing assembly welded to the fixing portion.

[0011] In some embodiments, the housing has a groove at the opening, and the welded portions of the cover and the manifold are located within the groove. In some embodiments, the bend closest to the welded portion is located within the groove.

[0012] Embodiments of this application also provide a battery pack including the aforementioned battery cells.

[0013] Embodiments of this application also provide an electronic device, which includes a battery pack comprising the aforementioned battery cells.

[0014] The technical solution of this application increases the thickness of the welded part to be greater than the maximum thickness of the disk surface. The thicker welded part can provide a better fit with the outer shell, reduce the assembly difficulty of the collector disk and the outer shell, and thus improve the assembly accuracy of the collector disk and the outer shell. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application 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 some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A schematic cross-sectional view of a battery cell according to an embodiment of this application is shown.

[0017] Figure 2A It shows Figure 1 An enlarged schematic diagram of region A1 of the battery cell in the embodiment shown.

[0018] Figure 2B It shows Figure 1 A plan view of the current collector of a battery cell in the embodiment shown.

[0019] Figure 2C It shows Figure 2B The diagram shows a cross-sectional view of the collector plate at section C1-C1.

[0020] Figure 3 A cross-sectional schematic diagram of a battery cell according to another embodiment of this application is shown.

[0021] Figure 4A It shows Figure 1 An enlarged schematic diagram of region A2 of the battery cell in the embodiment shown.

[0022] Figure 4B It shows Figure 1 A plan view of the current collector of a battery cell in the embodiment shown.

[0023] Figure 4C It shows Figure 4B The diagram shows a cross-sectional view of the collector plate at section C2-C2.

[0024] Figure 4D It shows Figure 4B A schematic diagram of the face of the collector plate shown.

[0025] Figure 4E It shows Figure 4B A schematic diagram of the fixing part of the collector plate shown.

[0026] Figure 5A A plan view of a manifold according to another embodiment of this application is shown.

[0027] Figure 5B It shows Figure 5A The diagram shows a cross-sectional view of the collector plate at section C3-C3.

[0028] Figure 6 A partial cross-sectional schematic diagram of a manifold according to another embodiment of this application is shown.

[0029] Figure 7 A partial cross-sectional schematic diagram of a manifold according to another embodiment of this application is shown.

[0030] Figure 8 A partial cross-sectional schematic diagram of a manifold according to another embodiment of this application is shown.

[0031] Figure 9 A schematic diagram is shown when the electronic device according to an embodiment of this application is a vehicle. Detailed Implementation

[0032] To better understand the spirit of the embodiments of this application, the following description is based on some preferred embodiments of this application.

[0033] Embodiments of this application will be described in detail below. Throughout this specification, identical or similar components and components having identical or similar functions are indicated by similar reference numerals. The embodiments described herein with reference to the accompanying drawings are illustrative and diagrammatic in nature and are intended to provide a basic understanding of this application. The embodiments of this application should not be construed as limiting this application.

[0034] As used herein, the terms “approximately,” “generally,” “substantially,” and “about” are used to describe and indicate minor variations. When used in conjunction with an event or situation, these terms may refer to examples in which the event or situation occurred precisely or in examples in which the event or situation occurred very approximately.

[0035] In this specification, unless otherwise specified or limited, relative terms such as “central,” “longitudinal,” “lateral,” “front,” “rear,” “right,” “left,” “inner,” “outer,” “lower,” “higher,” “horizontal,” “vertical,” “above,” “below,” “above,” “below,” “top,” “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) should be interpreted as referring to the directions described in the discussion or depicted in the accompanying drawings. These relative terms are used for descriptive convenience only and do not require that this application be constructed or operated in a particular orientation.

[0036] For ease of description, "first," "second," "third," etc., can be used in this article to distinguish different components of a figure or a series of figures. "First," "second," "third," etc., are not intended to describe the corresponding components.

[0037] In some cases, in the welding and sealing of the battery cell's casing and cover, the current collector (such as the negative electrode current collector) is bent and assembled in contact with the cover and / or casing, and then welded in place. In some existing technologies, the current collector contacts both the casing and cover simultaneously, and the current collector, casing, and cover are welded together. To reduce the weight and cost of the current collector and to facilitate welding with the electrode tabs, the thickness of the current collector is minimized. However, because in existing technologies, the current collector is usually designed with a uniform wall thickness and is bent on a substrate of the same thickness, when welding with the casing and / or cover, the deformation of the substrate itself at the bend of the current collector makes the welding pins of the current collector more prone to deformation relative to the surface after welding to the electrode assembly. This deformation increases the difficulty of assembling the current collector with the casing. Furthermore, the casing of power batteries is typically made of steel (steel shell), primarily due to steel's high physical stability, compressive strength, and chemical stability. This provides better protection for the battery's internal structure, preventing mechanical damage and electrolyte leakage, thus enhancing battery safety. Therefore, steel shells are widely used. Besides steel, aluminum and aluminum-plastic film can also be used for the casing of power batteries. To improve the battery's internal conductivity, effectively reduce internal resistance, meet the demands of high energy density, and facilitate better welding with the current collectors of the electrode components, copper is the mainstream material for the negative electrode current collector in the industry. Welding the current collector to the steel shell is a dissimilar material welding process. Compared to welding similar materials, dissimilar material welding is prone to welding stress, cracks, or deformation problems. Insufficient toughness of the weld joint and the presence of porosity or cracks can also lead to oxidation and airtightness issues. In view of the above technical problems, this application provides a single battery cell.

[0038] Figure 1 A schematic cross-sectional view of a battery cell 100A according to an embodiment of this application is shown. See also Figure 1 As shown, the battery cell 100A of this application can be exemplified by a cylindrical battery for specific implementation. In some embodiments, the battery cell 100A can be a 4680 cylindrical battery (46mm in diameter, 80mm in height), a 4695 cylindrical battery (46mm in diameter, 95mm in height), or a 46120 cylindrical battery (46mm in diameter, 120mm in height). Here, the diameter refers to the outer diameter of the casing.

[0039] The battery cell 100A includes a housing assembly 200, which includes a housing 210 and a cover 220. One end of the housing 210 forms an opening 205. Specifically, the housing 210 may include an end wall 111 and a side wall 109 surrounding the end wall 111. As long as a stable sealing and electrical connection can be formed, the connection between the end wall 111 and the side wall 109 can be achieved in various ways, such as integral stamping, integral casting, or separate welding. The side wall 109 can be cylindrical or follow any other closed-loop contour that matches the end wall 111. In this embodiment, the outer edge of the end wall 111 is circular, and the side wall 109 is cylindrical and surrounds the outer edge of the end wall 111. The end of the side wall 109 opposite to the end wall 111 forms an opening 205, and the cover 220 covers the opening 205. The cover 220 is fixedly connected to the end of the side wall 109 at the opening 205. The ends of the cover 220 and the side wall 109 can be welded together, for example, by laser welding, or mechanically connected by other methods. The connection between the cover 220 and the side wall 109 needs to achieve both a fixed and sealed connection. The housing 210 and the cover 220 of the housing assembly 200 together define a receiving space, which can be used to house the electrode assembly 120. The receiving space can also be used to house the electrolyte and other necessary battery components.

[0040] Specifically, the outer diameter of the outer casing 210 can be determined according to the specific dimensions of the electrode assembly 120. For example, the outer diameter of the outer casing 210 can be 18mm, 21mm, 46mm, etc. The material of the outer casing 210 can be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the cover 220 can be steel, such as stainless steel or nickel-plated steel, or aluminum alloy or composite materials of steel and aluminum, etc., which can meet the battery energy density requirements while also possessing strength, reliability, and sealing properties, and can be adjusted to meet the needs of lightweight battery design as much as possible. To prevent the outer casing 210 from rusting during long-term use, a rust-preventive material, such as metallic nickel, can be plated on the surfaces of the outer casing 210 and the cover 220.

[0041] The electrode assembly 120 can be mainly formed by winding positive and negative electrode sheets, with a separator provided between the positive and negative electrode sheets. The wound electrode assembly 120 can have a central through hole 120c, and the electrode assembly 120 and the central through hole 120c can have a common central axis Lx. The extending direction of the central axis Lx is the axial direction of the electrode assembly 120, and the height direction of the battery cell 100A can be parallel to the axial direction of the electrode assembly 120.

[0042] The positive electrode sheet may include a positive current collector and a positive active material, the positive active material being coated on the surface of the positive current collector; the positive current collector may include a coated area coated with the positive active material and an uncoated area not coated with the positive active material, the uncoated area being wound up and used to form the positive electrode tab of the electrode assembly 120. In some embodiments, the positive electrode tab of the electrode assembly 120 is located on the side of the electrode assembly 120 facing the end wall 111. The negative electrode sheet includes a negative current collector and a negative active material, the negative active material being coated on the surface of the negative current collector; the negative current collector includes a coated area coated with the negative active material and an uncoated area not coated with the negative active material, the uncoated area being wound up and used to form the negative electrode tab of the electrode assembly 120. In some embodiments, the negative electrode tab of the electrode assembly 120 is located on the side of the electrode assembly 120 facing the opening 205. Taking a lithium-ion battery cell as an example, the material of the negative current collector may be copper. The material of the positive current collector may be aluminum. The positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode active material can be carbon or silicon, etc. The separator material can be, for example, PP (polypropylene) or PE (polyethylene), etc. In order to protect and insulate the electrode assembly 120, an insulating film can also be wrapped around the electrode assembly 120. The insulating film can be synthesized from PP, PE, PET (polyethylene terephthalate), PVC (polyvinyl chloride), or other polymer materials.

[0043] The battery cell 100A also includes a first current collector 310A and a second current collector 320 electrically connected to the electrode assembly 120. The first current collector 310A is disposed between the cover 220 and the electrode assembly 120, and can be welded to the negative electrode tab of the electrode assembly 120 facing the opening 205 and the side wall 109 of the outer casing 210, thereby electrically connecting the first current collector 310A between the electrode assembly 120 and the side wall 109 of the outer casing assembly 200. In some such embodiments, the first current collector 310A is a negative current collector. In some implementations, the first current collector 310A can be welded to the cover 220 to similarly achieve its electrical connection with the outer casing assembly 200.

[0044] The terminal post 160 can pass through and is insulated from the end wall 111. In some embodiments, the terminal post 160 can be made of a conductive metallic material. For example, the material of the terminal post 160 can be aluminum (Al). In some embodiments, the terminal post 160 is the positive terminal of the battery cell 100A. The terminal post 160 is electrically insulated from the end wall 111 of the housing 210. Electrical insulation between the terminal post 160 and the end wall 111 can be achieved in various ways. For example, insulation can be achieved by placing an insulating gasket assembly between the terminal post 160 and the end wall 111. A second current collector 320 is disposed between the terminal post 160 and the electrode assembly 120. The positive electrode tab of the electrode assembly 120 facing the end wall 111 can be electrically connected to the terminal post 160 through the second current collector 320. In some such embodiments, the second current collector 320 is a positive current collector. In some embodiments, the axial directions of the first current collector 310A, the second current collector 320, and the electrode assembly 120 can coincide and extend along the central axis Lx.

[0045] Figure 2A It shows Figure 1 An enlarged schematic diagram of region A1 of the battery cell 100A in the embodiment shown. Figure 2B It shows Figure 1 A plan view of the first current collector 310A of the battery cell 100A in the embodiment shown. Figure 2C It shows Figure 2B The diagram shows a cross-sectional view of the first collector disk 310A at section C1-C1. For simplicity, the first collector disk will be referred to simply as the collector disk in the following description.

[0046] See Figures 2A to 2C As shown, the collector plate 310A may include a plate surface 312 and a fixing part 315 connected to the periphery of the plate surface 312. The plate surface 312 may extend in a plane perpendicular to the central axis Lx. The planar shape of the plate surface 312 may be circular. The fixing part 315 may be disposed around the plate surface 312.

[0047] The fixing portion 315 may include a connecting portion 316 connected to the disk surface 312, a welding portion 318 welded to the side wall 109 of the housing assembly 200, and a transition portion 317 connecting the connecting portion 316 and the welding portion 318. The connecting portion 316 may extend in a plane perpendicular to the central axis Lx. The welding portion 318 may be the end of the fixing portion 315 away from the disk surface 312.

[0048] The transition portion 317 is provided with at least one bend. In this embodiment, it is schematically shown that the transition portion 317 is provided with two bends, namely a first bend Pc1 and a second bend Pc2. It should be understood that the bend arrangement described below is only an exemplary embodiment, and the bends can be arranged in any suitable manner to extend the weld portion of the collector plate 310A to the appropriate position for welding with the side wall 109 as required.

[0049] The thickness of the welding portion 318 is T0, which in this embodiment is along the axial direction of the electrode assembly 120. According to an embodiment of this application, the thickness T0 of the welding portion 318 is greater than the maximum thickness T3 of the disk surface 312. For the collector disk 310A with a bent portion to cause the fixing portion 315 to bend, it is necessary to assemble it relative to the side wall 109 before welding the fixing portion 315 to the side wall 109. Compared with the prior art where the collector disk has a uniform wall thickness, by configuring the thickness T0 of the welding portion 318 to be greater than the maximum thickness T3 of the disk surface 312, the thicker welding portion 318 can reduce the probability of deformation or reduce the degree of deformation, making the welding portion 318 more stably contact the side wall 109, reducing the assembly difficulty of the collector disk 310A and the housing, and thus improving the assembly accuracy of the collector disk 310A and the housing.

[0050] In some embodiments, the top of the welded portion 318 may contact the cover 220. A portion of the fixing portion 315 of the manifold 310A may contact and be fixedly connected to the cover 220, so that the manifold 310A, the sidewall 109, and the cover 220 together form a triple weld. That is, the manifold 310A with the bent fixing portion 315 can be used in the triple weld scheme to meet the assembly accuracy requirements of the scheme.

[0051] In this embodiment, the bend closest to the disk surface 312 in the transition portion 317 is the first bend portion Pc1. The first bend portion Pc1 causes the transition portion 317 to bend at approximately 90° towards the cover 220. The portion of the first bend portion Pc1 near the weld portion 318 is the first bend connecting segment Pt1, and the thickness of the first bend connecting segment Pt1 is T1, wherein the thickness T1 can be the minimum thickness of the first bend connecting segment Pt1. In one example, the thickness T1 of the first bend connecting segment Pt1 ranges from 0.3mm to 0.9mm, preferably from 0.4mm to 0.6mm. The thickness T1 of the first bend connecting segment Pt1 can be greater than the maximum thickness T3 of the disk surface 312. In some embodiments, the overall thickness of the disk surface 312 can be substantially uniform. The portion of the first bend portion Pc1 near the disk surface 312 is the connecting portion 316, and the thickness T6 of the connecting portion 316 can be no greater than the maximum thickness T3 of the disk surface 312. This makes the first bent portion Pc1 of the transition portion 317 thicker after bending. By increasing the thickness of the portion of the first bent portion Pc1 near the welding portion 318, the thickened portion can act as a deformation-resistant area. After welding the current collector 310A and the electrode assembly 120, the deformation of the isolation disk surface 312 or the easily bent area (e.g., the connecting portion 316) can be reduced, thus reducing the risk of unwanted bending of the current collector 310A. This ensures good assembly between the transition portion 317 of the current collector 310A and the side wall 109, improves assembly accuracy, and facilitates welding between the transition portion 317 of the current collector 310A and the side wall 109.

[0052] More specifically, the transition portion 317 is further provided with a second bending portion Pc2 near the welding portion 318. The second bending portion Pc2 causes the transition portion 317 to bend at approximately 90° toward the side wall 109, so that the welding portion 318 extends to the position where it is welded to the side wall 109. The side of the second bending portion Pc2 facing the cover 220 can contact the cover 220. By providing the first bending portion Pc1 and the second bending portion Pc2, the collector plate is formed as a double-bending structure.

[0053] A first bent connecting segment Pt1 is provided between the first bent portion Pc1 and the second bent portion Pc2, and a second bent connecting segment Pt2 is provided between the second bent portion Pc2 and the welded portion 318. The first bent connecting segment Pt1 can extend vertically along the direction of the central axis Lx. The second bent connecting segment Pt2 can extend radially along the disk surface 312. In some embodiments, the thickness T1 of the first bent connecting segment Pt1 can be the same as the thickness T2 of the second bent connecting segment Pt2.

[0054] In some embodiments, the thickness T1 of the first bent connecting segment Pt1 and / or the thickness T2 of the second bent connecting segment Pt2 can be greater than the maximum thickness T3 of the disk surface 312. In this embodiment, both the first bent portion Pc1 and the second bent portion Pc2 can serve as areas to prevent deformation, and increasing the thickness of the first bent connecting segment Pt1 and / or the second bent connecting segment Pt2 can further reduce the risk of unwanted bending of the collector disk 310A, ensuring good assembly and assembly accuracy.

[0055] In some embodiments, the thickness T1 of the first bent connecting section Pt1 and the thickness T2 of the second bent connecting section Pt2 can be substantially uniform and substantially the same. Such identical thicknesses T1 and T2 are beneficial for stamping. The thickness T6 of the connecting portion 316 is greater than or equal to T3. In one example, the maximum thickness T3 of the disk surface 312 ranges from 0.1mm to 0.5mm, preferably from 0.15mm to 0.3mm. This thinner disk surface 312 facilitates pressure relief while ensuring stable welding. Furthermore, the thickness T6 of the connecting portion 316 is not less than the maximum thickness T3 of the disk surface 312, which better achieves the bending resistance effect of the transition portion 317. In some embodiments, the thickness T1 of the first bent connecting section Pt1 is greater than the thickness T6 of the connecting portion 316 to better achieve bending resistance and reduce the risk of unwanted bending of the manifold 310A.

[0056] In this embodiment, the disk surface 312 and the fixing part 315 of the collector disk 310A are an integral structure, and the disk surface 312 and the fixing part 315 are made of the same material, for example, both the disk surface 312 and the fixing part 315 can be made of copper substrate. It should be understood that because the collector disk 310A is an integral structure, therefore... Figures 2A to 2C The connection between the disk surface 312 and the fixing part 315 is an integral structure, with no connection interface. The integral structure of the collector disk 310A allows for higher structural strength. In embodiments where the collector disk 310A is an integral structure, the disk surface 312 can be thinned or the transition part 317 thickened to form the desired collector disk 310A structure, facilitating welding of the collector disk 310A to the sidewall 109.

[0057] In some embodiments, at least a portion of the disk surface 312 and / or the connecting portion 316 is used for welding to the negative electrode tab of the electrode assembly 120, that is, the tab welding portion 335 formed by welding the current collector 310A to the negative electrode tab of the electrode assembly 120 may be located in the disk surface 312 and / or the connecting portion 316. Figure 2B In this configuration, the tab welding portion 335 is located only on the disk surface 312 and avoids the connecting portion 316. It should be understood that... Figure 2B Only one tab welding part 335 is shown in the figure for simplification, but multiple tab welding parts 335 may be provided on the collector plate 310A.

[0058] To improve the welding performance of the current collector 310A, an additional transition layer material (intermediate layer) can be added to enhance weldability. Therefore, the current collector 310A can be designed to include a substrate and a plating layer on at least a portion of the substrate surface. The substrate material of the current collector 310A can be copper. The material of the negative electrode tab can also be copper. The plating layer of the current collector 310A can be applied to the surfaces of the disk surface 312 and / or the welding portion between the connecting portion 316 and the negative electrode tab.

[0059] The corrosion resistance of the current collector 310A and the welding strength between the current collector 310A and the negative electrode tab can be improved by setting a plating layer. The sidewall 109 of the housing 210 may include a substrate and a plating layer on at least a portion of the surface of the substrate. The substrate of the sidewall 109 may be steel. The surface of the portion of the fixing part 315 that is welded to the sidewall 109 is provided with a plating layer, and / or the surface of the portion of the sidewall 109 that is welded to the fixing part 315 is provided with a plating layer to improve the corrosion resistance of the sidewall 109 and / or the fixing part 315 and to improve the welding strength between the sidewall 109 and the fixing part 315. In some embodiments, the plating layers of the current collector 310A and the sidewall 109 may be Ni layers, Cr layers, Zn layers, etc., respectively. The thickness of the plating layer may be much smaller than the thickness of the corresponding substrate of the current collector 310A and the sidewall 109, where "much smaller" means a difference of one order of magnitude.

[0060] Figure 3 A schematic cross-sectional view of a battery cell 100B according to another embodiment of this application is shown. Figure 4A It shows Figure 1 An enlarged schematic diagram of region A2 of the battery cell 100B in the embodiment shown. Figure 4B It shows Figure 1 A plan view of the current collector 310B of the battery cell 100B in the embodiment shown. Figure 4C It shows Figure 4B The diagram shows a cross-sectional view of the collector plate 310B at section C2-C2. Figure 4D It shows Figure 4B A schematic diagram of the disk surface 312 of the collector disk 310B shown. Figure 4E It shows Figure 4B A schematic diagram of the fixing part 315 of the collector plate 310B shown. Figures 3 to 4E Several aspects of the illustrated embodiments are related to the above references. Figures 1 to 2C Similar to the descriptions below, the main focus is on... Figures 3 to 4E The differences between the illustrated embodiments are as follows.

[0061] See Figures 3 to 4EAs shown, the disk surface 312 and the fixing part 315 of the manifold 310B are separate structures that are fixedly connected to each other. The connecting part 316 is located between the first bending part Pc1 and the disk surface 312, and the connecting part 316 is fixedly connected to the outer edge 312e of the disk surface 312. Various fixed connection methods can be used between the connecting part 316 and the disk surface 312, such as welding, riveting, and gluing. The connection between the connecting part 316 and the disk surface 312, located between the transition part 317 and the disk surface 312, provides a structure that facilitates secondary connection and fixing. The separate molding structure of the manifold 310B can isolate the welding area between the disk surface 312 and the electrode assembly 120 through the bending part, and the fixed connection structure between the connecting part 316 and the disk surface 312 can buffer deformation forces. This separate molding structure of the manifold 310B can improve the flexibility of molding areas with different thicknesses.

[0062] In this embodiment, the thickness T6 of the connecting portion 316 can be greater than or equal to the maximum thickness T3 of the disk surface 312. In one example, the maximum thickness T3 of the disk surface 312 ranges from 0.1mm to 0.5mm, and preferably from 0.15mm to 0.3mm. A thinner disk surface 312 facilitates pressure relief while ensuring stable welding. The fact that the thickness T6 of the connecting portion 316 is not less than the maximum thickness T3 of the disk surface 312 better achieves the bending resistance of the transition portion 317 and reduces the risk of unwanted bending of the manifold 310B.

[0063] In this embodiment, the substrate of the disk surface 312 of the collector plate 310B and the substrate of the fixing part 315 may be different. In some embodiments, the substrate of the fixing part 315 may be the same as the substrate of the housing 210. In one example, the substrate of the disk surface 312 may be copper, the substrate of the fixing part 315 may be steel, and the substrate of the housing 210 may be steel. If the substrate of the fixing part 315 is the same as the substrate of the disk surface 312, then the fixing part 315 and the housing 210 are welded from dissimilar materials (e.g., copper and steel). The selection of the substrate of the fixing part 315 can facilitate the welding requirements of the fixing part 315 and the housing 210, solving the problem of difficult welding of dissimilar materials. Preferably, the substrate of the fixing part 315 is the same as the substrate of the housing 210. Using the same substrate for the fixing part 315 and the housing 210 can facilitate welding, improve welding yield and welding strength.

[0064] In some embodiments, when tested with a Vickers hardness tester using the same test method, the hardness difference between the disk surface 312 and the fixing portion 315 is at least 10 HV (Vickers hardness units). In some embodiments, the hardness of the fixing portion 315 is greater than the hardness of the disk surface 312. The different hardnesses of the disk surface 312 and the fixing portion 315 can ensure the connection strength and bending strength of the transition portion 317, while also taking into account the pressure relief capacity of the disk surface 312. Differentiating the hardness treatment of the disk surface 312 and the fixing portion 315 of the manifold can be achieved by adopting a zoned strengthening strategy, specifically through differentiated heat treatment, surface modification, or deformation strengthening. This application does not impose specific limitations on the processing technology for localized hardness enhancement.

[0065] In some embodiments, the tab welding portion formed by welding the current collector 310A to the negative electrode tab of the electrode assembly 120 can be located on the plate surface 312 and / or the connecting portion 316. In some embodiments, the tab welding portion of the current collector 310A is only located on the plate surface 312, avoiding the connecting portion 316. That is, only the plate surface 312 is used for welding with the electrode assembly 120, and the connecting portion 316 is located around the tab welding portion, which can avoid affecting the welding and avoid deformation caused by the welding process. Since the plate surface 312 and the connecting portion 316 can be made of different materials, the plate surface 312 can be selected from materials that are more conducive to welding with the negative electrode tab of the electrode assembly 120. For example, the plate surface 312 can be made of copper to facilitate the welding of the plate surface 312 and the negative electrode tab.

[0066] Combination Figures 1 to 4E As shown, both the collector plate 310A and the collector plate 310B can be provided with at least one buffer structure 350. The buffer structure 350 can be provided on the plate surface 312. The buffer structure 350 can be a ring structure surrounding the center of the plate surface 312. The buffer structure 350 can protrude toward the cover 220. By adding a buffer structure 350 for preventing deformation on the plate surface 312, the effect of buffering deformation and resisting bending can be enhanced. The top of the buffer structure 350 toward the cover 220 can be lower than the top of the transition portion 317 (in this embodiment, the top surface of the second bending connecting section Pt2). Specifically, the vertical distance between the top of the buffer structure 350 and the top of the transition portion 317 is H2. In some embodiments, H2 ≥ 0.05 mm, preferably, H2 ≥ 0.1 mm.

[0067] Both the collector plate 310A and the collector plate 310B can have at least one opening structure 319 on their respective plate surface 312. For example, four opening structures 319 can be provided. The opening structures 319 are not provided in the connecting part 316. By providing opening structures 319 on the plate surface 312, the weight of the collector plate can be reduced and the exhaust can be facilitated.

[0068] The total area of ​​at least one opening structure 319 is S1. In this embodiment, the total area of ​​four opening structures 319 is S1. The area defined by the boundary of the connecting portion 316 away from the disk surface 312 is S2. That is, S2 is the area of ​​the portion of each of the collector disks 310A and 310B extending in a plane perpendicular to the central axis Lx. In some embodiments, the total area S1 of the opening structures 319 ranges from 0.5% × S2 to 85% × S2. Preferably, the total area S1 of the opening structures 319 ranges from 10% × S2 to 50% × S2. The range of values ​​for the total area S1 of the opening structures 319 can satisfy a good pressure relief and explosion-proof effect. It is understandable that a larger opening structure 319 would improve the pressure relief and explosion protection effect, but reduce the overall strength of the disc surface 312. Therefore, setting the opening structure 319 on the disc surface 312 can minimize the problem of reduced strength and easy deformation of the fixing part 315 due to reduced loss. At the same time, controlling the overall area of ​​the opening structure 319 can also minimize the strength loss of the disc surface 312 and minimize the deformation of the disc surface 312 due to welding, thereby transmitting the deformation to the fixing part 315.

[0069] Furthermore, the side wall 109 of the outer casing 210 may be provided with a groove 210r at the opening 205. The outer edge of the cover 220 may be located within the groove 210r. A portion of the second bent connecting section Pt2 of the transition portion 317 of each of the collectors 310A and 310B extends into the groove 210r, and the welding portion 318 of the fixing portion 315 may be located within the groove 210r. By providing the groove 210r for overlapping the welding portion 318 with the outer casing 210, the fitting accuracy between the collector and the outer casing can be further improved.

[0070] In some embodiments, the width of the groove 210r is D1 (see... Figure 4A The width D1 can be ≥0.15mm and less than the wall thickness of the outer shell 210. This range of width D1 ensures the overlapping effect between the outer shell 210 and the transition portion 317 and the cover 220, while also ensuring the strength requirements of the outer shell 210. The depth of the groove 210r is H1 (see...). Figure 4A In some embodiments, the depth H1 can range from 0.05mm to 0.5mm. Preferably, the depth H1 can range from 0.1mm to 0.3mm. The total thickness of the cover 220 and the weld portion 318 can be no greater than the depth H1 of the groove 210r. This range of depth H1 can accommodate the thickness requirements of the transition portion 317 and meet the fitting requirements of the cover 220 and the outer shell 210, satisfying the weld penetration requirements (i.e., strength requirements).

[0071] Figure 5AA plan view of a manifold 310C according to another embodiment of this application is shown. Figure 5B It shows Figure 5A The diagram shows a cross-sectional view of the manifold 310C at section C3-C3. See also... Figure 5A and Figure 5B As shown, the collector plate 310C includes at least two fixing portions 315; in this embodiment, four fixing portions 315 are shown as an example. The four fixing portions 315 are spaced apart circumferentially on the plate surface 312 and are evenly positioned circumferentially on the plate surface 312. Connecting portions 316 are fixedly connected to the plate surface 312. A transition portion 317 is connected to the connecting portions 316 and may have at least one bent portion. The structure of the transition portion 317 can be the same as described above. Figures 1 to 4E Similar to the description. The disk surface 312 and the fixing part 315 of the collector disk 310C can be a separate structure that is fixedly connected to each other, or, as described above. Figure 5A and Figure 5B The integrated structure shown.

[0072] The electrode tab welding portion 335 of the manifold 310C can be located at the connecting portion 316, such as Figure 5A As shown. For the sake of simplicity, Figure 5A Only one tab welding portion 335 is shown, but each connecting portion 316 may have its own tab welding portion 335. In other embodiments, the tab welding portion 335 may be located on the disk surface 312, or it may be located on both the connecting portion 316 and the disk surface 312.

[0073] Figure 6 A partial cross-sectional schematic diagram of the manifold 310D according to another embodiment of this application is shown. See also Figure 6 As shown, the transition portion 317 of the collector plate 310D includes a first bent portion Pc1 near the plate surface 312 and a second bent portion Pc2 near the welding portion 318. The transition portion 317 may also include a third bent portion Pc3 and a fourth bent portion Pc4 located between the first bent portion Pc1 and the second bent portion Pc2. A first bent connecting segment Pt1 connects the first bent portion Pc1 and the third bent portion Pc3, and a second bent connecting segment Pt2 connects the second bent portion Pc2 and the sidewall 109. A third bent connecting segment Pt3 connects the third bent portion Pc3 and the fourth bent portion Pc4. The third bent connecting segment Pt3 is arranged parallel to the second bent connecting segment Pt2, and the third bent connecting segment Pt3 and the second bent connecting segment Pt2 are stacked along the axial direction of the electrode assembly 120. In this embodiment, by providing four bent portions in the transition portion 317, the transition portion 317 is formed as a stacked structure. Furthermore, the thickness of the transition portion 317 increases from the first bend portion Pc1 to a value greater than the maximum thickness of the disk surface portion 312.

[0074] Figure 7 A partial cross-sectional schematic diagram of a manifold 310B according to another embodiment of this application is shown. Figure 7 Several aspects of the illustrated embodiments are related to the above references. Figures 4A to 4E Similar to what is described. Figure 7 The difference in the illustrated embodiment is that the weld portion 318 of the transition portion 317 is located within the groove 210r, which is used to overlap the weld portion 318 with the sidewall 109. The cover 220 may be located outside the groove 210r.

[0075] Figure 8 A partial cross-sectional schematic diagram of a manifold 310E according to another embodiment of this application is shown. See also Figure 8 As shown, the transition portion 317 has a bent portion, namely a first bent portion Pc1. The first bent portion Pc1 can be located within the groove 210r. At least a portion of the cover 220 can be located within the groove 210r. In other embodiments where the transition portion 317 has multiple bent portions, one of the multiple bent portions closest to the weld portion 318 can be provided within the groove 210r.

[0076] According to another aspect of the embodiments of this application, see Figure 9 As shown, this application also provides an electronic device 1000. For ease of explanation, the following embodiments use a vehicle as an example to illustrate the electronic device 1000. The vehicle can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, but are not limited thereto. The working part is the vehicle body 1001, and the battery pack 1002 is disposed at the bottom of the vehicle body 1001, providing electrical power support for the vehicle's movement or the operation of electrical components within the vehicle. The working part of the electronic device 1000 is electrically connected to the battery pack 1002 to obtain electrical power support. In other embodiments, the electronic device 1000 can also be a mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, and power tool, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; the working part can obtain electrical energy from the battery pack 1002 and perform corresponding work, such as a fan blade rotation unit or a vacuum cleaner suction unit. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the aforementioned electronic device 1000.

[0077] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A battery cell, characterized in that, include: A housing assembly, including a housing, one end of which forms an opening; The housing assembly also includes a cover that closes to the opening and, together with the housing, defines an accommodating space. Electrode assembly, housed within the housing space; A current collector is electrically connected between the electrode assembly and the housing assembly, and includes a disk surface and a fixing portion connected to the periphery of the disk surface. The fixing portion includes a connecting portion connected to the disk surface, a welding portion welded to the housing assembly, and a transition portion connecting the connecting portion and the welding portion. The transition portion has at least one bending portion, and the thickness of the welding portion is greater than the maximum thickness of the disk surface.

2. The battery cell according to claim 1, characterized in that, The bending portion closest to the disk surface is the first bending portion, and the minimum thickness of the portion of the transition portion located on the side of the first bending portion near the welding portion is greater than the maximum thickness of the disk surface.

3. The battery cell according to claim 2, characterized in that, The bending portion further includes a second bending portion near the welding portion, a first bending connection segment is provided between the first bending portion and the second bending portion, and a second bending connection segment is provided between the second bending portion and the welding portion, wherein at least one of the thickness of the first bending connection segment and the thickness of the second bending connection segment is greater than the maximum thickness of the disk surface.

4. The battery cell according to claim 3, characterized in that, The transition section further includes a third bending connection section located between the first bending connection section and the second bending section, the third bending connection section being arranged parallel to the second bending connection section and stacked along the axial direction of the electrode assembly.

5. The battery cell according to claim 1, characterized in that, Meets at least one of the following: The disk surface and the fixing part are separate structures that are fixedly connected to each other. The bending part includes a first bending part near the disk surface. The connecting part is located between the first bending part and the disk surface and is fixedly connected to the disk surface. The collector plate includes at least two fixing parts, which are spaced apart and evenly positioned around the circumference of the plate surface, and the connecting parts are respectively fixedly connected to the plate surface. The electrode assembly includes a tab that is welded and fixed to the collector plate. The collector plate is welded to the tab of the electrode assembly to form a tab welding part. The tab welding part is located on the plate surface and / or the connecting part. The substrate of the disc surface is different from the substrate of the fixing part; The hardness difference between the disc surface and the fixing part is at least 10 HV.

6. The battery cell according to claim 1, characterized in that, The surface of the collector plate is provided with at least one opening structure, but the opening structure is not provided in the connecting part; The total area of ​​the at least one opening structure is S1, and the area of ​​the collector plate defined by the boundary of the connecting portion away from the plate surface is S2. S1 ranges from 0.5%×S2 to 85%×S2, or from 10%×S2 to 50%×S2.

7. The battery cell according to claim 1, characterized in that, Meets at least one of the following: The electrode assembly includes a tab that is welded and fixed to the current collector, and a plating layer is provided on the surface of the welding portion between the disk surface and the tab. The surface of the fixing part and the welded part of the outer shell assembly is provided with a plating layer; The surface of the portion of the outer casing assembly that is welded to the fixing part is provided with a plating layer.

8. The battery cell according to claim 3, characterized in that, The outer casing has a groove at the opening, and the welded portion of the cover and the collector plate is located within the groove; The bend closest to the weld is located within the groove.

9. A battery pack, characterized in that, Includes the battery cell described in any one of claims 1 to 8.

10. An electronic device, characterized in that, The battery pack includes the battery cells according to any one of claims 1 to 8.

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