Battery cell, battery, method for manufacturing battery cell, and manufacturing equipment

Abstract

The embodiments of the present application relate to the technical field of batteries, and more particularly to a battery cell, a battery, a method for manufacturing a battery cell, and a manufacturing device. A battery cell includes an end cover and a first seal, wherein the end cover is provided with a medium injection hole, and the medium injection hole penetrates the end cover along the thickness direction of the end cover; a flange is provided on the outer peripheral surface of the first seal, and the first seal is connected to the hole wall of the medium injection hole or the outer surface of the end cover through the flange to seal the medium injection hole. The battery cell provided by the embodiments of the present application is conducive to concentrating the energy of the first seal at the flange during welding, so as to form a good sealing connection between the flange and the medium injection hole or the outer surface of the end cover, reduce the occurrence of welding defects, and prevent substances inside and outside the battery cell from flowing through the welding defect position to affect the normal use of the battery cell.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of batteries, and in particular, to a battery cell, a battery, a method for manufacturing a battery cell, and a manufacturing device. Background Art

[0002] The basic unit of a power battery is a battery cell. Existing battery cells generally include a shell and an electrode assembly. The shell contains electrolyte, and the electrode assembly is immersed in the electrolyte. The shell of the battery cell includes a shell and an end cap connected to the shell. The end cap is provided with an electrode terminal, a medium injection hole, etc.

[0003] During assembly, the electrode assembly is first electrically connected to the electrode terminal, then the electrode assembly is placed in the shell, and the end cover is welded and sealed to the shell to assemble into a semi-finished product. After a series of processes such as liquid injection, formation and capacity, the medium injection hole is sealed to obtain a battery cell.

[0004] The function of sealing the medium injection hole is to isolate the inside of the battery cell from the external environment, ensure the chemical environment required for the battery cell to work, and prevent electrolyte leakage. In the prior art, a seal is welded to the medium injection hole to seal the medium injection hole.

[0005] However, after welding, pinholes are likely to appear at the weld between the medium injection hole and the seal, causing the electrolyte inside the battery cell to leak out, or external impurities to enter the battery cell, affecting the chemical environment inside the battery cell. Summary of the invention

[0006] In view of the above problems, the embodiments of the present application provide a battery cell, a battery, a method for manufacturing a battery cell, and a manufacturing device, which can reduce welding defects, enable the seal to form a good seal on the medium injection hole, and prevent the internal and external substances of the battery cell from communicating with each other.

[0007] According to one aspect of an embodiment of the present application, a battery cell is provided, including:

[0008] An end cover, wherein a medium injection hole is provided on the end cover, and the medium injection hole penetrates the end cover along the thickness direction of the end cover;

[0009] A first sealing member is provided with a flange on its outer peripheral surface, and the first sealing member is connected to the hole wall of the medium injection hole or the outer surface of the end cover through the flange to seal the medium injection hole.

[0010] By adopting the above scheme, the medium injection hole and the first sealing member are welded by the flange. Since the contact area between the flange and the hole wall of the medium injection hole or the outer surface of the end cover is small, it is beneficial to concentrate the energy on the flange during welding, so as to form a good sealing connection between the flange and the medium injection hole or the outer surface of the end cover, reduce the occurrence of welding defects, and prevent the substances inside and outside the battery cell from flowing through the welding defect position to affect the normal use of the battery cell.

[0011] In some embodiments, the first seal includes a bottom wall and a side wall arranged around the bottom wall, the bottom wall and the side wall form a hollow structure with one end open, the opening facing the outside of the battery cell, and the flange is located on the outer circumferential surface of the side wall.

[0012] By adopting the above scheme, during the process of welding the first sealing member to the medium injection hole, the welding equipment can be inserted from the open end of the first sealing member, and the side wall is squeezed outward around the circumference, and then the flange is squeezed, so that the entire circle of the flange is stressed and sealed with the medium injection hole, preventing the electrolyte inside the battery cell from generating steam during welding and overflowing from the un-pressed weld to cause pinholes, which is beneficial to improving the welding quality.

[0013] In some embodiments, the flange is disposed proximate the open end of the first seal.

[0014] By adopting the above solution, it is advantageous for the welding equipment to weld the first sealing member from the side where the outer surface of the end cover is located, which makes the operation more convenient and facilitates the control of the welding force.

[0015] In some embodiments, along the direction from the end of the side wall close to the opening to the bottom wall, the side wall is inclined toward the axis of the medium injection hole to reduce the contact area between the side wall and the hole wall of the medium injection hole.

[0016] By adopting the above scheme, firstly, it is convenient to install the first sealing member into the medium injection hole; secondly, since the flange is close to the open end of the first sealing member, after the first sealing member is installed into the medium injection hole, only the flange is in contact with the hole wall of the medium injection hole, thereby reducing the contact area between the first sealing member and the medium injection hole, which is convenient for concentrating energy on the flange during welding, so as to form a good sealing connection between the flange and the outer surface of the medium injection hole or the end cover.

[0017] In some embodiments, the medium injection hole has a welding bevel on one side close to the outer surface of the end cover. The welding bevel is inclined toward the axis of the medium injection hole along the direction from the outer surface of the end cover to the inner surface of the end cover, and the flange is connected to the welding bevel.

[0018] By adopting the above scheme, since the side wall of the first sealing member is also inclined, after the first sealing member is installed into the medium injection hole, the flange is not radially outward in the medium injection hole. By setting the welding bevel and making the flange located on the welding bevel, when the welding equipment squeezes the side wall from the outside of the end cover, the direction of the pressure is not along the axial direction of the medium injection hole, or along the radial direction of the medium injection hole, but is basically consistent with the direction of the flange, thereby positively squeezing the flange, making the flange and the welding bevel fit more closely, which is beneficial to the welding process. After the flange is crushed, the welding energy is still concentrated only on the flange.

[0019] In some embodiments, the inclination angle between the side wall and the axis of the medium injection hole is A, the inclination angle between the welding slope and the axis of the medium injection hole is B, A>B, so as to reduce the contact area between the side wall and the hole wall of the medium injection hole.

[0020] By adopting the above solution, during the welding process, when the welding equipment squeezes the side wall, the flange is gradually crushed. After the flange is crushed, the side wall and the welding bevel are still in contact only at the position close to the opening of the side wall, which is beneficial for the energy to always be concentrated on the flange during the welding process.

[0021] In some embodiments, a stress release structure is provided at the connection between the side wall and the bottom wall.

[0022] By adopting the above scheme, when the welding equipment squeezes the side wall during welding and causes the angle between the side wall and the bottom wall to change, the stress release structure can release the stress generated during the deformation process, so that the stress balance is achieved between the side wall and the bottom wall, reducing the possibility of cracking of the weld in the later stage.

[0023] In some embodiments, the medium injection hole includes a first hole segment and a second hole segment, the first hole segment is close to the outside of the battery cell, and the second hole segment is close to the inside of the battery cell. The first seal is located in the first hole segment, and the diameter of the first hole segment is larger than the diameter of the second hole segment to prevent the first seal from falling into the inside of the battery cell.

[0024] By adopting the above solution, during the welding process of the first sealing member, it is prevented that the welding equipment applies too much pressure to the first sealing member, causing the first sealing member to fall into the battery cell.

[0025] In some embodiments, a second sealing member is disposed in the second bore section to seal the second bore section.

[0026] By adopting the above solution, before welding the first sealing member, the second sealing member can be installed into the second hole section to prevent impurities such as welding slag generated during welding from falling into the battery cell.

[0027] In some embodiments, the bottom of the first hole segment is provided with rounded corners.

[0028] By adopting the above solution, it is easy to clean the bottom of the first hole section and reduce the residual electrolyte at the bottom of the first hole section, thereby preventing the high heat generated during welding from evaporating the residual electrolyte to produce steam and damage the weld.

[0029] In some embodiments, a groove is provided on a surface of the first sealing member close to the second sealing member, and the groove is recessed in a direction away from the second sealing member to avoid the second sealing member.

[0030] By adopting the above solution, when the second sealing member protrudes toward the first sealing member, the provision of the groove can prevent the first sealing member from interfering with the second sealing member and causing difficulty in installing the first sealing member.

[0031] In some embodiments, an annular groove is provided on the outer surface of the end cover, and the annular groove is used to limit the deformation of the end cover during the welding process of the first sealing member, and the annular groove surrounds the medium injection hole.

[0032] By adopting the above solution, the deformation during the welding process is limited to the area within the annular groove, and the deformation of the area far away from the medium injection hole is reduced or avoided.

[0033] According to a second aspect of the embodiments of the present application, a battery is provided, comprising the battery cell of the above embodiment.

[0034] According to a third aspect of an embodiment of the present application, a method for manufacturing a battery cell is provided, comprising:

[0035] Providing an end cover, wherein a medium injection hole is provided on the end cover, and the medium injection hole penetrates the end cover along the thickness direction of the end cover;

[0036] Providing a first sealing member, wherein a flange is provided on an outer peripheral surface of the first sealing member;

[0037] The first sealing member is welded to the hole wall of the medium injection hole or the outer surface of the end cover through the flange to seal the medium injection hole.

[0038] In some embodiments, the welding method is resistance welding.

[0039] By adopting the above scheme, since the area of ​​the flange is small and the resistance is large, a large amount of heat can be generated at the flange under a small current to soften the flange, and the flange can be sealed and connected to the hole wall of the medium injection hole or the outer surface of the end cover by applying pressure.

[0040] According to a fourth aspect of an embodiment of the present application, there is provided a battery cell manufacturing device, comprising:

[0041] The first device is used to provide an end cover, the end cover is provided with a medium injection hole, and the medium injection hole penetrates the end cover along the thickness direction of the end cover;

[0042] A second device is used to provide a first sealing member, wherein a flange is provided on an outer peripheral surface of the first sealing member;

[0043] The third device is used to weld the first sealing member to the hole wall of the medium injection hole or the outer surface of the end cover through the flange to seal the medium injection hole.

[0044] In some embodiments, the third device includes:

[0045] A positive electrode pressure head, used for electrical connection with the end cap;

[0046] A negative electrode pressure head, used for being electrically connected to the first sealing member;

[0047] The negative electrode pressure head comprises a press-fitting portion, which is used to press the flange against the hole wall of the medium injection hole or the outer surface of the end cover.

[0048] By adopting the above scheme, the negative electrode pressure head cooperates with the positive electrode pressure head to electrically connect the end cover and the first seal, and the current passes through the flange, causing the flange to heat up and soften. In addition, the negative electrode pressure head can also squeeze the medium injection hole through the pressing part, softening the flange and crushing the flange at the same time, so that it is tightly connected with the medium injection hole or the outer surface of the end cover.

[0049] In some embodiments, the press-fitting portion includes a revolving surface for making the circumference of the flange abut against the hole wall of the medium injection hole or the outer surface of the end cover.

[0050] By adopting the above scheme, the flange circumference is squeezed by the rotating surface to form a sealed connection with the medium injection hole, thereby preventing the electrolyte inside the battery cell from generating steam and overflowing from the un-squeezed weld during welding to form pinholes, which is beneficial to improving the welding quality.

[0051] In some embodiments, the third device further comprises:

[0052] The insulating member is arranged between the positive electrode pressure head and the negative electrode pressure head, and is used to insulate the positive electrode pressure head from the negative electrode pressure head.

[0053] By adopting the above solution, the positive electrode pressure head and the negative electrode pressure head can only be electrically connected through the end cover and the first seal, which increases the current between the end cover and the first seal, accelerates the melting and softening of the flange, and improves welding efficiency and welding quality.

[0054] In some embodiments, a receiving cavity is provided inside the positive electrode pressure head and / or the negative electrode pressure head for receiving a cooling medium to prevent the positive electrode pressure head and / or the negative electrode pressure head from melting.

[0055] By adopting the above solution, the cooling medium can reduce the temperature of the positive electrode pressure head and the negative electrode pressure head during welding, preventing the positive electrode pressure head and the negative electrode pressure head from overheating and softening and sticking to the first seal or the end cover assembly under higher pressure.

[0056] In the embodiment of the present application, the medium injection hole and the first sealing member are welded through a flange. Since the contact area between the flange and the hole wall of the medium injection hole or the outer surface of the end cover is small, it is beneficial to concentrate energy on the flange during welding, so as to form a good sealing connection between the flange and the medium injection hole or the outer surface of the end cover, reduce the occurrence of welding defects, and prevent substances inside and outside the battery cell from flowing through the welding defect position and affecting the normal use of the battery cell.

[0057] The above description is only an overview of the technical solution of the embodiment of the present application. In order to more clearly understand the technical means of the embodiment of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0059] Figure 1 It is a schematic diagram of the structure of an electrical device in one embodiment of the present application.

[0060] Figure 2 Schematic diagram of the structure of a battery in one embodiment of the present application.

[0061] Figure 3 Schematic diagram of the structure of a battery module in one embodiment of the present application.

[0062] Figure 4 It is a schematic diagram of the exploded structure of a battery cell in one embodiment of the present application.

[0063] Figure 5 This is a schematic structural diagram of the connection between the first sealing member and the hole wall of the medium injection hole in one embodiment of the present application.

[0064] Figure 6 This is a schematic diagram of the structure in which the first sealing member is connected to the outer surface of the end cover in one embodiment of the present application.

[0065] Figure 7 It is a three-dimensional structural diagram of the first sealing member in one embodiment of the present application.

[0066] Figure 8 It is a schematic diagram of the exploded structure of the first sealing member and the medium injection hole in one embodiment of the present application.

[0067] Fig. 9This is a schematic structural diagram of a second sealing member installed in a medium injection hole in one embodiment of the present application.

[0068] Fig.10 Detailed description of the invention The figure is a flow chart of a method for manufacturing a battery cell in one embodiment of the present invention.

[0069] Fig.11 It is a composition diagram of a battery cell manufacturing device in one embodiment of the present application.

[0070] Fig.12 It is a schematic cross-sectional structural diagram of the third device in one embodiment of the present application.

[0071] Fig.13 This is a schematic diagram of the third device in one embodiment of the present application when welding the first sealing member and the end cover.

[0072] Description of reference numerals: 2, electrical equipment; 200, battery; 210, controller; 220, motor; 300, battery module; 201, first housing; 202, second housing; 400, battery cell; 20, housing; 30, electrode assembly; 31, positive electrode tab; 32, negative electrode tab; 40, end cap; 41, outer surface of end cap; 412, annular groove; 42, electrode terminal; 43, medium injection hole; 431, first hole section; 4311, fillet; 43 2. Second hole section; 4321. Second sealing member; 44. First sealing member; 441. Bottom wall; 442. Side wall; 443. Flange; 444. Stress release structure; 4441. Arc segment; 445. Groove; 45. Welding bevel; 500. First device; 600. Second device; 700. Third device; 701. Positive electrode pressure head; 702. Negative electrode pressure head; 703. Pressing part; 7031. Rotating surface; 704. Insulating member; 705. Accommodating chamber. DETAILED DESCRIPTION

[0073] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0074] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0075] The terms "comprising" and "having" and any variations thereof in the specification, claims and drawings of this application are intended to cover but not exclude other contents. The word "a" or "an" does not exclude the presence of a plurality.

[0076] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase "embodiments" in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0077] The term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0078] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of the battery cells of the present application. For example, in the description of the present application, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present application.

[0079] In addition, the expressions of the indicated directions, such as the X direction, the Y direction, and the Z direction, used to illustrate the operation and construction of the components of the battery cell of this embodiment are not absolute but relative, and although these indications are appropriate when the components of the battery pack are in the positions shown in the figures, when these positions change, these directions should be interpreted differently to correspond to the changes.

[0080] In addition, the terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0081] In the description of the present application, unless otherwise specified, "plurality" means more than two (including two), and similarly, "multiple groups" means more than two groups (including two).

[0082] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, the "connection" or "connection" of a mechanical structure may refer to a physical connection. For example, the physical connection may be a fixed connection, such as a fixed connection through a fixing member, such as a fixed connection through a screw, bolt or other fixing member; the physical connection may also be a detachable connection, such as a mutual snap connection or snap connection; the physical connection may also be an integral connection, such as welding, bonding or integral molding to form a connection for connection. The "connection" or "connection" of a circuit structure may refer to an electrical connection or a signal connection in addition to a physical connection. For example, it may be a direct connection, that is, a physical connection, or it may be an indirect connection through at least one intermediate element, as long as the circuit is connected, or it may be the internal connection of two elements; the signal connection may refer to a signal connection through a media medium, such as a radio wave, in addition to a signal connection through a circuit. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0083] In the present application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries or magnesium-ion batteries, etc., and the embodiments of the present application do not limit this. Battery cells may be cylindrical, flat, rectangular or other shapes, etc., and the embodiments of the present application do not limit this. Battery cells are generally divided into three types according to the packaging method: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of the present application do not limit this.

[0084] The battery cell includes a housing, an electrode assembly and an electrolyte. The electrode assembly is composed of a positive electrode sheet, a negative electrode sheet and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector. The current collector not coated with the positive active material layer protrudes from the current collector coated with the positive active material layer. The current collector not coated with the positive active material layer serves as the positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive current collector can be aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector. The current collector not coated with the negative active material layer protrudes from the current collector coated with the negative active material layer. The current collector not coated with the negative active material layer serves as the negative electrode tab. The material of the negative current collector can be copper, and the negative active material can be carbon or silicon, etc. In order to ensure that a large current can pass without melting, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together. The material of the isolation film can be PP or PE. In addition, the electrode assembly can be a winding structure or a laminated structure, and the embodiments of the present application are not limited thereto.

[0085] The shell includes a shell and an end cover. The shell is a hollow cavity structure with an opening. The end cover is provided with a medium injection hole, and the medium injection hole penetrates the end cover along the thickness direction of the end cover. After the electrode assembly is loaded into the shell from the opening, the opening is closed with the end cover to seal the shell to prevent gaseous, liquid or solid substances from flowing between the inside and outside of the shell, affecting the performance of the battery cell.

[0086] During the assembly process of the battery cell, the electrode assembly is first electrically connected to the electrode terminal, and then the electrode assembly is installed in the shell, and the shell is sealed with an end cover to form a semi-finished product. After the semi-finished battery cell is assembled, only the medium injection hole can realize the material flow between the inside and outside of the shell. After a series of processes such as liquid injection, formation and capacity, the medium injection hole is finally sealed to obtain a complete battery cell.

[0087] The purpose of sealing the medium injection hole is to isolate the inside of the battery cell from the external environment, ensure the chemical environment required for the battery cell to work, and prevent electrolyte leakage. In the prior art, a sealant is welded to the medium injection hole to seal the medium injection hole.

[0088] However, after welding, pinhole defects are likely to occur at the weld between the medium injection hole and the seal, causing the electrolyte inside the battery cell to leak out, or external impurities to enter the battery cell, affecting the chemical environment inside the battery cell.

[0089] After research, the inventor found that this is because during the welding process of the seal and the medium injection hole, due to the large contact area between the seal and the medium injection hole, it is difficult to concentrate energy at a certain place. Therefore, a large amount of heat needs to be input to heat the seal and the side wall of the medium injection hole, so that the contact part of the seal and the medium injection hole becomes soft or even melts to form a molten pool. When the molten pool solidifies, the two are connected together to form a weld. During the heating process, the electrolyte remaining in the medium injection hole or the electrolyte inside the battery cell will evaporate to form electrolyte vapor, increasing the air pressure inside the battery cell. At this time, since there is a molten pool between the seal and the medium injection hole, the metal of the molten pool is soft, and the gas inside the battery cell overflows from the molten pool under the action of air pressure. The molten pool is flushed open by the gas to form pinholes. After the molten metal solidifies, the pinholes still exist, resulting in poor sealing of the battery cell and causing the internal and external substances of the battery cell to circulate.

[0090] In view of the above problems, an embodiment of the present application provides a battery cell, which arranges a flange on the sealing member so that the medium injection hole and the first sealing member are welded through the flange. Since the contact area between the flange and the hole wall of the medium injection hole or the outer surface of the end cover is small, it is beneficial to concentrate energy on the flange during welding, so as to form a good sealing connection between the flange and the medium injection hole or the outer surface of the end cover, reduce the occurrence of welding defects, and prevent substances inside and outside the battery cell from flowing through the welding defect position and affecting the normal use of the battery cell.

[0091] The battery in the embodiments of the present application can be applicable to various devices using batteries, such as mobile phones, portable devices, laptop computers, electric vehicles, electric toys, electric tools, electric vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft, etc., but are not limited to these.

[0092] like Figure 1 As shown, Figure 1 A schematic diagram of the structure of an electric device provided in one embodiment of the present application is taken as an example of a car 2. The car 2 can be a fuel car, a gas car or a new energy car. The new energy car can be a pure electric car, a hybrid car or an extended-range car, etc. The car 2 includes a battery 200, a controller 210 and a motor 220. The battery 200 is used to supply power to the controller 210 and the motor 220 as the operating power supply and driving power supply of the car 2. For example, the battery 200 is used to supply power to the controller 210 and the motor 220 during the start-up, navigation and operation of the car 2. For example, the battery 200 supplies power to the controller 210, the controller 210 controls the battery 200 to supply power to the motor 220, and the motor 220 receives and uses the power of the battery 200 as the driving power supply of the car 2, replacing or partially replacing the fuel or natural gas to provide driving power for the car 2.

[0093] like Figure 2 As shown, in order to make the battery 200 achieve higher functions to meet the use requirements, the battery 200 may include a plurality of battery modules 300 electrically connected to each other, and the battery 200 includes a box body, and the box body includes a first box body 201, a second box body 202 and a plurality of battery modules 300, wherein the first box body 201 and the second box body 202 are interlocked, and the plurality of battery modules 300 are arranged in a space enclosed by the first box body 201 and the second box body 202. The first box body 201 and the second box body 202 may be made of aluminum, aluminum alloy or other metal materials. In some embodiments, the first box body 201 and the second box body 202 are sealed and connected.

[0094] like Figure 3 As shown, the battery module 300 may include one or more battery cells 400. When the battery module 300 includes multiple battery cells 400, the multiple battery cells 400 may be electrically connected in series, in parallel, or in a hybrid manner to achieve a larger current or voltage, wherein the hybrid means a combination of series and parallel. In addition, the multiple battery cells 400 may be arranged according to a predetermined rule, such as Figure 3 As shown, the battery cell 400 can be placed upright, with the height direction of the battery cell 400 consistent with the Z direction, and multiple battery cells 400 are arranged side by side along the Y direction; or, the battery cell 400 can be placed flat, with the width direction of the battery cell 400 consistent with the Z direction, and multiple battery cells 400 can be stacked in at least one layer along the Z direction, and each layer includes multiple battery cells 400 arranged along the X direction or the Y direction.

[0095] like Figure 4 As shown, it is a schematic diagram of the structure of a battery cell 400 provided in an embodiment of the present application, wherein the battery cell 400 includes a shell 20, one or more electrode assemblies 30 placed in the shell 20, and an end cover 40 that cooperates with the shell 20 to seal the electrode assembly 30 in the shell 20. The shell 20 is a hollow cavity. For example, one of the surfaces of the shell 20 has an opening, that is, the plane does not have a shell wall so that the inside and outside of the shell 20 are connected, so that the electrode assembly 30 can be accommodated in the shell 20, and the end cover 40 is combined with the shell 20 at the opening of the shell 20 to form a hollow cavity.

[0096] The shell 20 is determined according to the shape of one or more electrode assemblies 30 after being combined. For example, the shell 20 may be a hollow cuboid, a hollow cube, or a hollow cylinder. For example, when the shell 20 is a hollow cuboid or a cube, one of the planes of the shell 20 is an open surface, that is, the plane does not have a shell wall so that the inside and outside of the shell 20 are connected; when the shell 20 is a hollow cylinder, one of the circular side surfaces of the shell 20 is an open surface, that is, the circular side surface does not have a shell wall so that the inside and outside of the shell 20 are connected.

[0097] In another embodiment of the present application, the housing 20 may be made of metal material or plastic. Optionally, the housing 20 is made of aluminum or aluminum alloy.

[0098] like Figure 4 As shown, two electrode terminals 42 and a medium injection hole 43 are provided on the end cover 40. The end cover 40 is combined with the shell 20 at the opening of the shell 20 and covers the opening of the shell 20. For example, the end cover 40 can be a metal plate and is connected to the shell 20 by welding, so that the electrode assembly 30 is sealed in the shell 20.

[0099] The two electrode terminals 42 are respectively a positive terminal and a negative terminal, and the electrode terminals 42 are electrically connected to the electrode assembly 40 .

[0100] Each electrode assembly 30 has a positive electrode tab 31 and a negative electrode tab 32 . The positive electrode tab 31 of one or more electrode assemblies 30 is connected to the positive terminal, and the negative electrode tab 32 of one or more electrode assemblies 30 is connected to the negative terminal.

[0101] like Figure 5 As shown, Figure 5 for Figure 4 A schematic cross-sectional view of the medium injection hole 43 along the plane where the axis is located, the medium injection hole 43 penetrates the end cover 40 along the thickness direction of the end cover 40; a first sealing member 44 is provided on the end cover 40, and a flange 443 is provided on the outer peripheral surface of the first sealing member 44, and the first sealing member 44 is connected to the hole wall of the medium injection hole 43 or the outer surface 41 of the end cover through the flange 443 to seal the medium injection hole 43.

[0102] The medium injection hole 43 can be a cylindrical hole or a prismatic hole, or a combination of holes of different shapes, as long as the inside and outside of the end plate can communicate with each other.

[0103] The first seal 44 can be connected to the hole wall of the medium injection hole 43 or to the outer surface 41 of the end cover. The medium injection hole 43 can be sealed to isolate the inside of the battery cell 400 from the external environment to prevent the substances inside and outside the battery cell 400 from flowing between each other.

[0104] like Figure 5 As shown, when the first sealing member 44 is connected to the hole wall of the medium injection hole 43 , the shape of the flange 443 matches the shape of the hole wall of the medium injection hole 43 , thereby sealing the medium injection hole 43 around the inner wall of the medium injection hole 43 .

[0105] like Figure 6As shown, when the first seal 44 is connected to the outer surface 41 of the end cover, the flange 443 can be a ring of any shape, and the medium injection hole 43 is located inside the ring. The material inside the battery cell 400 can flow in the medium injection hole 43 and within the range limited by the flange 443, while the material outside the battery cell 400 can only flow within the range outside the flange 443. Therefore, the materials inside and outside the battery cell 400 will not communicate with each other.

[0106] By adopting the above scheme, the medium injection hole 43 and the first sealing member 44 are connected by the flange 443. Since the contact area between the flange 443 and the hole wall of the medium injection hole 43 or the outer surface 41 of the end cover is small, it is beneficial to concentrate the energy on the flange 443 during welding, so as to form a good sealing connection between the flange 443 and the medium injection hole 43 or the outer surface 41 of the end cover, reduce the occurrence of welding defects, and prevent the substances inside and outside the battery cell 400 from flowing through the welding defect position and affecting the normal use of the battery cell 400.

[0107] The energy during welding includes but is not limited to heat and pressure. Since the contact area between the flange 443 and the hole wall of the medium injection hole 43 or the outer surface 41 of the end cover is small, during the welding process, the heat will be concentrated at the flange 443, thereby accelerating the melting and softening speed of the metal at the flange 443, and there is no need for long-term heat input, thereby reducing the degree of increase in the internal air pressure of the battery cell 400 caused by long-term heating during welding, and preventing the internal air pressure of the battery cell 400 from being too high and breaking through the welding heating position to form a pinhole defect. In addition, during the welding process, when a small pressure is applied to the first sealing member 44, the pressure is concentrated at the flange 443, so that there is a large pressure between the flange 443 and the medium injection hole 43 or the outer surface 41 of the end cover, accelerating the combination of the flange 443 and the medium injection hole 43 or the outer surface 41 of the end cover, and making it more tightly combined. During the welding process, the combined position is not easily broken by the gas inside the battery cell 400 to form a pinhole defect.

[0108] like Figure 5 , Figure 6 and Figure 7 As shown, Figure 7 This is a three-dimensional structural diagram of the first seal 44 in an embodiment of the present application. In some embodiments, the first seal 44 includes a bottom wall 441 and a side wall 442 arranged around the bottom wall 441. The bottom wall 441 and the side wall 442 form a hollow structure with one end open, and the opening faces the outside of the battery cell 400. The flange 443 is located on the outer peripheral surface of the side wall 442.

[0109] In some embodiments, at least one section of the medium injection hole 43 is cylindrical, the bottom wall 441 of the first sealing member 44 is circular, the side wall 442 is annular, the flange 443 is located on the outer circumference of the side wall 442 , and the flange 443 is connected to the inner circumference of the medium injection hole 43 .

[0110] By adopting the above scheme, during the process of welding the first sealing member 44 to the medium injection hole 43, the welding equipment can be inserted from the open end of the first sealing member 44, and the side wall 442 is squeezed outward around the circumference, thereby squeezing the flange 443, so that the flange 443 is subjected to force around the entire circle and is sealed and connected to the medium injection hole 43, thereby preventing the electrolyte inside the battery cell 400 from generating steam during the welding process and overflowing from the un-extruded weld to form pinholes, which is beneficial to improving the welding quality.

[0111] like Figure 5 , Figure 6 and Figure 7 As shown, in some embodiments, the flange 443 is disposed proximate to the open end of the first seal 44 .

[0112] By adopting the above solution, it is advantageous for the welding equipment to weld the first sealing member 44 from the side where the outer surface 41 of the end cover is located, which makes the operation more convenient and facilitates the control of the welding force.

[0113] like Figure 8 As shown, Figure 8 It is a schematic diagram of the exploded structure of the first sealing member 44 and the medium injection hole 43. In some embodiments, the side wall 442 is inclined in the direction from the end of the opening to the bottom wall 441 toward the axis OO' close to the medium injection hole 43 to reduce the contact area between the side wall 442 and the hole wall of the medium injection hole 43. Figure 8 The middle angle A shows the direction and magnitude of the inclination angle between the side wall 442 and the axis OO′ of the medium injection hole 43 .

[0114] The side wall 442 is inclined along the above direction, so that the diameter of the first seal 44 gradually increases from the end close to the bottom wall 441 to the end away from the bottom wall 441. In the process of installing the first seal 44 into the medium injection hole 43, the end with a smaller diameter is installed first, which is beneficial to reduce the difficulty of installing the first seal 44 into the medium injection hole 43 and improve the assembly efficiency of the first seal 44.

[0115] Secondly, since the flange 443 is close to the open end of the first sealing member 44, after the first sealing member 44 is installed into the medium injection hole 43, only the flange 443 is in contact with the hole wall of the medium injection hole 43, thereby reducing the contact area between the first sealing member 44 and the medium injection hole 43, which is beneficial for concentrating energy on the flange 443 during welding, so as to form a good sealing connection between the flange 443 and the medium injection hole 43.

[0116] like Figure 8 As shown, in some embodiments, the medium injection hole 43 has a welding bevel 45 on one side close to the outer surface 41 of the end cover. From the direction close to the outer surface 41 of the end cover to the direction away from the outer surface 41 of the end cover, the welding bevel 45 is inclined in the direction of the axis OO' close to the medium injection hole 43, and the flange 443 is connected to the welding bevel 45. The connection state is referred to Figure 1 . Figure 8 The middle angle B shows the direction and size of the inclination angle between the welding bevel 45 and the axis OO′ of the medium injection hole 43 .

[0117] Since the side wall 442 of the first sealing member 44 is inclined, after the first sealing member 44 is installed in the medium injection hole 43, the flange 443 is not radially outwardly facing the medium injection hole 43, but has an angle of about 90° with the side wall 442. When the inner wall of the medium injection hole 43 corresponding to the flange 443 is roughly parallel to the side wall 442 of the first sealing member 44, the flange 443 can basically face the side wall 442 of the medium injection hole 43. In the above embodiment, by providing the welding bevel 45 and positioning the flange 443 on the welding bevel 45, the flange 443 is close to facing the welding bevel 45. When the welding equipment presses the side wall 442 from the outside of the end cover 40, the direction of the pressure is basically consistent with the direction of the flange 443, thereby positively pressing the flange 443, making the flange 443 fit more closely with the welding bevel 45, and preventing the first sealing member 44 from being pressed into the battery cell 400.

[0118] In addition, when the first sealing member 44 is installed in the medium injection hole 43 , since the medium injection hole 43 has the welding slope 45 , the first sealing member 44 is installed more easily.

[0119] like Figure 8 As shown, in some embodiments, A>B, so as to reduce the contact area between the side wall 442 and the hole wall of the medium injection hole 43 .

[0120] In other words, the side wall 442 of the first sealing member 44 and the welding slope 45 are inclined in the same direction relative to the axis OO′ of the medium injection hole 43 , and the slope of the side wall 442 of the first sealing member 44 is greater than the slope of the welding slope 45 .

[0121] By adopting the above solution, during the welding process, when the welding equipment squeezes the side wall 442, the flange 443 is gradually crushed. After the flange 443 is crushed, the side wall 442 and the welding bevel 45 are still in contact only at a position close to the opening of the side wall 442, which is beneficial for the energy to always be concentrated on the flange 443 during the welding process.

[0122] The flange 443 being crushed refers to the phenomenon that the flange 443 becomes soft after being subjected to the heat input by the welding equipment, and is deformed after being squeezed by the welding equipment, thereby increasing the contact area between the flange 443 and the welding bevel 45 .

[0123] In some embodiments, a stress release structure 444 is provided at the connection between the side wall 442 and the bottom wall 441 of the first sealing member 44 .

[0124] like Figure 5 , Figure 6 , Figure 7 and Figure 8 As shown, in some embodiments, the stress release structure 444 can be an arc segment 4441 arranged between the side wall 442 and the bottom wall 441. During the welding process, when the welding equipment squeezes the side wall 442 and gradually crushes the flange 443, causing the angle between the side wall 442 and the bottom wall 441 to change, the curvature of the arc segment 4441 is reduced to adapt to the change in the angle between the side wall 442 and the bottom wall 441.

[0125] In some other embodiments, the stress release structure 444 can be a corrugated structure arranged between the side wall 442 and the bottom wall 441. During the welding process, when the angle between the side wall 442 and the bottom wall 441 changes, the corrugated structure is forced to expand to adapt to the change in the angle between the side wall 442 and the bottom wall 441.

[0126] The pleated structure refers to a structure having at least one circle of wave crests and at least one circle of wave troughs connected to the wave crests along the circumference of the side wall 442 .

[0127] By adopting the above solution, the stress release structure 444 can release the stress generated inside the material between the side wall 442 and the bottom wall 441 during the deformation process, so that the stress balance is achieved between the side wall 442 and the bottom wall 441, reducing the possibility of cracking of the weld in the later stage.

[0128] like Figure 5 , Figure 6 and Figure 8 As shown, in some embodiments, the medium injection hole 43 includes a first hole segment 431 and a second hole segment 432, the first hole segment 431 is close to the outside of the battery cell 400, and the second hole segment 432 is close to the inside of the battery cell 400, the first seal 44 is located in the first hole segment 431, and the diameter of the first hole segment 431 is larger than the diameter of the second hole segment 432 to prevent the first seal 44 from falling into the inside of the battery cell 400.

[0129] The first hole segment 431 and the second hole segment 432 may be coaxial or not. In addition, the first hole segment 431 and the second hole segment 432 may be directly transitioned through a step, or the first hole segment 431 and the second hole segment 432 may be gradually transitioned through a conical surface or a curved surface, which is not limited in the embodiments of the present application.

[0130] By adopting the above solution, during the welding process of the first sealing member 44 , it is possible to prevent the welding equipment from applying excessive pressure to the first sealing member 44 , thereby preventing the first sealing member 44 from falling into the battery cell 400 .

[0131] like Fig. 9 As shown, Fig. 9 Schematic diagram of a structure in which a second sealing member 4321 is installed in the medium injection hole 43 . In some embodiments, a second sealing member 4321 is provided in the second hole section 432 to seal the second hole section 432 .

[0132] The material of the second seal 4321 can be metal or non-metal. Optionally, the second seal 4321 is a component made of elastic sealing materials such as plastic parts and rubber parts. The second seal 4321 is inserted into the second hole section 432 in an extruded state to prevent the second seal 4321 from shaking in the second hole section 432 or falling into the battery cell 400.

[0133] By adopting the above solution, before welding the first sealing member 44 , the second sealing member 4321 can be installed into the second hole section 432 to prevent impurities such as welding slag generated during welding from falling into the battery cell 400 .

[0134] like Figure 5 , Figure 6 , Figure 8 and Fig. 9 As shown, in some embodiments, the bottom of the first hole segment 431 is provided with a rounded corner 4311 .

[0135] By adopting the above solution, it is easy to clean the bottom of the first hole section 431 and reduce the residual electrolyte at the bottom of the first hole section 431, thereby preventing the high heat generated during welding from evaporating the residual electrolyte to produce steam and damage the weld.

[0136] like Fig. 9 As shown, in some embodiments, a groove 445 is provided on a surface of the first sealing member 44 close to the second sealing member 4321 , and the groove 445 is recessed in a direction away from the second sealing member 4321 to avoid the second sealing member 4321 .

[0137] In some embodiments, a projection along the axis OO′ direction of the medium injection hole 43 falls within the groove 445 .

[0138] By adopting the above solution, when the second seal 4321 is not completely installed in the second hole section 432 and protrudes toward the first seal 44, the setting of the groove 445 can prevent the first seal 44 from interfering with the second seal 4321 and causing difficulty in installing the first seal 44.

[0139] like Figure 5 , Figure 6 , Figure 8 and Fig. 9 As shown, in some embodiments, an annular groove 412 is provided on the outer surface 41 of the end cover. The annular groove 412 is used to limit the deformation of the end cover 40 during the welding process of the first sealing member 44 . The annular groove 412 surrounds the medium injection hole 43 .

[0140] During the welding process, in order to make the first seal 44 and the end cover 40 more tightly combined, the welding equipment will apply external force to the first seal 44. During the welding process, the end cover 40 is heated as a whole, especially the part close to the medium injection hole 43 is heated more. Under the extrusion of the external force, the part of the end cover 40 close to the medium injection hole 43 is more likely to deform. At this time, the end cover 40 is divided into an area close to the medium injection hole 43 and an area far away from the medium injection hole 43 by the annular groove 412. The area close to the medium injection hole 43 is deformed, and the transmission medium is lost when it reaches the annular groove 412, so that the deformation will not be transmitted to the area far away from the medium injection hole 43, or the impact on the area far away from the medium injection hole 43 is small.

[0141] The area close to the medium injection hole 43 refers to the area within the annular groove 412 , and the area far from the medium injection hole 43 refers to the area outside the annular groove 412 .

[0142] In addition, during welding, an annular limiting component matching the annular groove 412 may be placed in the annular groove 412. The limiting component may be made of a material with a lower heat transfer efficiency or a material with a higher hardness. The limiting component limits the deformation of the area close to the medium injection hole 43, preventing the end cover 40 from continuously deforming and expanding in a direction away from the medium injection hole 43 during the extrusion of the flange 443, and at the same time can reduce or avoid deformation of the area away from the medium injection hole 43.

[0143] In summary, the embodiment of the present application welds the medium injection hole 43 and the first sealing member 44 through the flange 443. Since the contact area between the flange 443 and the hole wall of the medium injection hole 43 or the outer surface 41 of the end cover is small, it is beneficial to concentrate energy on the flange 443 during welding, so as to form a good sealing connection between the flange 443 and the medium injection hole 43 or the outer surface 41 of the end cover, reduce the occurrence of welding defects, and prevent substances inside and outside the battery cell 400 from flowing through the welding defect position and affecting the normal use of the battery cell 400.

[0144] According to a second aspect of the embodiments of the present application, a battery 200 is provided, comprising the battery cell 400 of the above-mentioned embodiment.

[0145] The battery 200 or even the electric device using the battery cell 400 of the above embodiment also has the above advantages.

[0146] In a third aspect of the present application, a method for manufacturing the battery cell 400 of the above embodiment is provided. Fig.10 As shown, Fig.10 The flowchart of the manufacturing method of the battery cell in one embodiment of the present application includes:

[0147] S1: providing an end cover 40 , on which a medium injection hole 43 is provided, and the medium injection hole 43 penetrates the end cover 40 along a thickness direction of the end cover 40 .

[0148] S2: Provide a first sealing member 44 , on the outer peripheral surface of which a flange 443 is provided.

[0149] S3: welding the first sealing member 44 to the hole wall of the medium injection hole 43 or the outer surface 41 of the end cover through the flange 443 to seal the medium injection hole 43 .

[0150] The order of the above steps is not completely in accordance with the above arrangement order. In the actual process of manufacturing the battery cell 400, the order of the above steps can be adjusted according to the actual situation, or performed simultaneously, or other steps can be added to manufacture other components of the battery cell 400, so as to finally obtain the required battery cell 400. For example: the order between S1 and S2 can be interchanged, or performed simultaneously, please refer to the embodiment of the battery cell 400 for details.

[0151] In addition, any method that can manufacture related components and connect related components falls within the protection scope of the embodiments of the present application, and the embodiments of the present application will not be described in detail here.

[0152] In some embodiments, the first sealing member 44 is welded to the hole wall of the medium injection hole 43 or the outer surface 41 of the end cover by resistance welding.

[0153] Resistance welding refers to a welding method that uses electric current to pass through the parts to be welded, using the resistance heat generated at the contact point of two adjacent parts to be welded as a heat source to locally heat the weldment to a molten or plastic state, and at the same time applies pressure to combine the metals.

[0154] The two parts to be welded in the embodiment of the present application are the end cap 40 and the first seal 44. By passing the current through the end cap 40 and the first seal 44, the resistance heat is generated at the contact part between the end cap 40 and the first seal 44, so that the end cap 40 and the first seal 44 are locally heated to a melted or soft plastic state, and at the same time, pressure is applied to the first seal 44, so that the first seal 44 is combined with the end cap 40. The contact part between the end cap 40 and the first seal 44 is the flange 443.

[0155] By adopting the above scheme, since the area of ​​the flange 443 is small and the resistance is large, a large amount of heat can be generated at the flange 443 under a small current to soften the flange 443, and pressure is applied to seal the flange 443 with the hole wall of the medium injection hole 43 or the outer surface 41 of the end cover, thereby improving the welding quality and reducing welding defects.

[0156] In a fourth aspect of the embodiments of the present application, a battery cell manufacturing device is provided, such as Fig.11 As shown, the manufacturing equipment of the battery cell provided in the embodiment of the present application includes:

[0157] The first device 500 is used to provide an end cover 40 , on which a medium injection hole 43 is provided. The medium injection hole 43 penetrates the end cover 40 along the thickness direction of the end cover 40 .

[0158] The second device 600 is used to provide a first sealing member 44 , and a flange 443 is provided on the outer peripheral surface of the first sealing member 44 .

[0159] The third device 700 is used to weld the first sealing member 44 to the hole wall of the medium injection hole 43 or the outer surface 41 of the end cover through the flange 443 to seal the medium injection hole 43 .

[0160] like Fig.12 , Fig.13 As shown, Fig.12 is a schematic cross-sectional structural diagram of the third device 700, Fig.13 It is a schematic diagram of the third device 700 welding the first seal 44 and the end cover 40 . In some embodiments, the third device 700 includes: a positive electrode pressure head 701 for electrically connecting to the end cover 40 ; and a negative electrode pressure head 702 for electrically connecting to the first seal 44 .

[0161] The negative electrode pressure head 702 includes a press-fitting portion 703 , and the press-fitting portion 703 is used to press the flange 443 against the hole wall of the medium injection hole 43 or the outer surface 41 of the end cover.

[0162] The press-fitting portion 703 is a component used to press the first sealing member 44 so that the first sealing member 44 is installed in the medium injection hole 43 . Specifically, the press-fitting portion 703 in the embodiment of the present application is used to press the flange 443 of the first sealing member 44 .

[0163] like Fig.13 As shown, in some embodiments, the negative electrode pressure head 702 is in contact with the first sealing member 44 through the press-fitting portion 703 to achieve electrical connection with the first sealing member 44, and the positive electrode pressure head 701 extends into the annular groove 412 of the outer surface 41 of the end cover and contacts the inner wall of the annular groove 412, which can not only achieve electrical connection with the end cover 40, but also limit the deformation of the end cover 40. Exemplarily, the positive electrode pressure head 701 contacts the inner ring side wall 442 of the annular groove 412 to limit the deformation of the end cover 40 portion within the annular groove 412.

[0164] By adopting the above scheme, the negative electrode pressure head 702 cooperates with the positive electrode pressure head 701 to electrically connect the end cover 40 and the first sealing member 44, and the current passes through the flange 443, causing the flange 443 to heat up and soften. In addition, the negative electrode pressure head 702 can also squeeze the medium injection hole 43 through the pressing portion 703, softening the flange 443 and crushing the flange 443, so that it is tightly connected to the medium injection hole 43 or the outer surface 41 of the end cover.

[0165] like Fig.13 As shown, in some embodiments, the press-fitting portion 703 includes a revolving surface 7031 for making the flange 443 abut against the hole wall of the medium injection hole 43 or the outer surface 41 of the end cover.

[0166] The revolving surface 7031 refers to the surface formed in space when a plane curve (single curvature, the plane of the curve is not perpendicular to the axis of rotation) or a space curve (double curvature) revolves around a fixed straight line (rotation center line CC'). Therefore, when the rotation center line CC' of the revolving surface 7031 coincides with the axis OO' of the medium injection hole 43, when the revolving surface 7031 is pressed against the first sealing member 44, the surface of the revolving surface 7031 used to press the flange 443 is circular, so that the circumference of the flange 443 is pressed at the same time.

[0167] The flange 443 is squeezed around the rotating surface 7031 to seal the flange 443 with the medium injection hole 43, thereby preventing the electrolyte inside the battery cell 400 from generating steam and overflowing from the un-squeezed weld during welding to form pinholes, thereby improving welding quality.

[0168] like Fig.12 , Fig.13 As shown, in some embodiments, the third device 700 further includes an insulating member 704 , which is disposed between the positive electrode pressure head 701 and the negative electrode pressure head 702 to insulate the positive electrode pressure head 701 from the negative electrode pressure head 702 .

[0169] By adopting the above scheme, the positive electrode pressure head 701 and the negative electrode pressure head 702 are insulated by the insulating member 704, so that the positive electrode pressure head 701 and the negative electrode pressure head 702 can only be electrically connected through the end cover 40 and the first seal 44, thereby increasing the current between the end cover 40 and the first seal 44, accelerating the melting and softening of the flange 443, and improving the welding efficiency and welding quality.

[0170] like Fig.12 , Fig.13 As shown, in some embodiments, a receiving cavity 705 is provided inside the positive electrode pressure head 701 and / or the negative electrode pressure head 702 for receiving a cooling medium to prevent the positive electrode pressure head 701 and / or the negative electrode pressure head 702 from melting.

[0171] Among them, the accommodating cavity 705 can be set only in the positive electrode pressure head 701, or only in the negative electrode pressure head 702, or in both the positive electrode pressure head 701 and the negative electrode pressure head 702. It can be determined specifically according to the material of the positive electrode pressure head 701 or the negative electrode pressure head 702. For example, if the melting point of the positive electrode pressure head 701 is lower than the highest temperature during welding, then the accommodating cavity 705 is set in the positive electrode pressure head 701. If the melting point of the positive electrode pressure head 701 is much higher than the highest temperature during welding, then the accommodating cavity 705 is set in the positive electrode pressure head 701 or not. The negative electrode pressure head 702 can also be set using the above principle, and the embodiment of the present application is not limited to this.

[0172] The cooling medium may be a liquid medium, a solid medium, or a gaseous medium, for example, water, dry ice, cold air, etc. In addition, the cooling medium may be flowing or non-flowing in the accommodating cavity 705, and the embodiment of the present application does not limit this.

[0173] By adopting the above solution, the cooling medium can reduce the temperature of the positive electrode pressure head 701 and the negative electrode pressure head 702 during welding, preventing the positive electrode pressure head 701 and the negative electrode pressure head 702 from overheating and softening and sticking to the first seal 44 or the end cover 40 assembly under higher pressure.

[0174] The features of the above-mentioned protected subjects and embodiments of the present application can be mutually referenced. If the structure allows, those skilled in the art can also flexibly combine the technical features of different embodiments to form more embodiments. For example, in the claims, any one of the embodiments claimed for protection can be used in any combination.

[0175] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell, characterized in that: include: An end cover, wherein the end cover is provided with a medium injection hole, and the medium injection hole penetrates the end cover along the thickness direction of the end cover; The first sealing member includes a bottom wall and a side wall arranged around the bottom wall, wherein the bottom wall and the side wall form a hollow structure with an opening at one end, wherein the opening faces the outside of the battery cell, and a flange is arranged on the outer peripheral surface of the side wall, and the first sealing member is connected to the hole wall of the medium injection hole or the outer surface of the end cover through the flange to seal the medium injection hole.

2. The battery cell according to claim 1, characterized in that: The flange is disposed adjacent to the open end of the first sealing member.

3. The battery cell according to claim 2, characterized in that: Along the direction from the end of the side wall close to the opening to the bottom wall, the side wall is inclined toward the direction of the axis of the medium injection hole to reduce the contact area between the side wall and the hole wall of the medium injection hole.

4. The battery cell according to claim 3, characterized in that: The medium injection hole has a welding bevel on one side close to the outer surface of the end cover. Along the direction from the outer surface of the end cover to the inner surface of the end cover, the welding bevel is inclined in the direction of the axis of the medium injection hole, and the flange is connected to the welding bevel.

5. The battery cell according to claim 4, characterized in that: The inclination angle between the side wall and the axis of the medium injection hole is A, and the inclination angle between the welding slope and the axis of the medium injection hole is B, A>B, so as to reduce the contact area between the side wall and the hole wall of the medium injection hole.

6. The battery cell according to claim 1, characterized in that: A stress release structure is arranged at the connection between the side wall and the bottom wall.

7. The battery cell according to any one of claims 1 to 6, characterized in that: The medium injection hole includes a first hole segment and a second hole segment, the first hole segment is close to the outside of the battery cell, and the second hole segment is close to the inside of the battery cell. The first seal is located in the first hole segment, and the diameter of the first hole segment is larger than the diameter of the second hole segment to prevent the first seal from falling into the inside of the battery cell.

8. The battery cell according to claim 7, characterized in that: A second sealing member is disposed in the second hole section to seal the second hole section.

9. The battery cell according to claim 7, characterized in that: The bottom of the first hole segment is provided with a rounded corner.

10. The battery cell according to claim 8, characterized in that: A groove is provided on a surface of the first sealing member close to the second sealing member, and the groove is recessed in a direction away from the second sealing member to avoid the second sealing member.

11. The battery cell according to claim 1, characterized in that: An annular groove is provided on the outer surface of the end cover, and the annular groove is used to limit the deformation of the end cover during the welding process of the first sealing member, and the annular groove surrounds the medium injection hole.

12. A battery, characterized in that: A battery cell comprising the battery cell according to any one of claims 1 to 11.

13. A method for manufacturing a battery cell, characterized in that: include: Providing an end cover, wherein the end cover is provided with a medium injection hole, and the medium injection hole penetrates the end cover along the thickness direction of the end cover; Providing a first sealing member, the first sealing member comprising a bottom wall and a side wall arranged around the circumference of the bottom wall, the bottom wall and the side wall forming a hollow structure with an opening at one end, the opening facing the outside of the battery cell, and a flange being arranged on an outer circumferential surface of the side wall; The first sealing member is welded to the hole wall of the medium injection hole or the outer surface of the end cover through the flange to seal the medium injection hole.

14. The method for manufacturing a battery cell according to claim 13, characterized in that: The welding method is resistance welding.

15. A battery cell manufacturing device, characterized in that: include: A first device is used to provide an end cover, wherein the end cover is provided with a medium injection hole, and the medium injection hole penetrates the end cover along the thickness direction of the end cover; A second device is used to provide a first sealing member, wherein the first sealing member includes a bottom wall and a side wall arranged around the circumference of the bottom wall, wherein the bottom wall and the side wall form a hollow structure with an opening at one end, wherein the opening faces the outside of the battery cell, and a flange is arranged on an outer circumferential surface of the side wall; The third device is used to weld the first sealing member to the hole wall of the medium injection hole or the outer surface of the end cover through the flange to seal the medium injection hole.

16. The manufacturing equipment according to claim 15, characterized in that The third device comprises: A positive electrode pressure head, used for being electrically connected to the end cap; A negative electrode pressure head, used for being electrically connected to the first sealing member; Wherein, the negative electrode pressure head comprises a pressing portion, and the pressing portion is used to press the flange against the hole wall of the medium injection hole or the outer surface of the end cover.

17. The manufacturing equipment according to claim 16, characterized in that The press-fitting portion comprises a revolving surface for making the circumference of the flange abut against the hole wall of the medium injection hole or the outer surface of the end cover.

18. The manufacturing equipment according to claim 16, characterized in that The third device also includes: The insulating member is disposed between the positive electrode pressure head and the negative electrode pressure head, and is used to insulate the positive electrode pressure head from the negative electrode pressure head.

19. The manufacturing equipment according to claim 16, characterized in that An accommodating cavity is provided inside the positive electrode pressure head and / or the negative electrode pressure head for accommodating a cooling medium to prevent the positive electrode pressure head and / or the negative electrode pressure head from melting.

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