Battery monomer, battery device and electric equipment

Abstract

The invention discloses a battery monomer, a battery device and electric equipment. The battery cell includes a housing, a first electrode lead-out member, and an electrode assembly. The first electrode lead-out piece is arranged on the shell. The electrode assembly is accommodated in the shell, the electrode assembly comprises a main body part and a plurality of first tabs led out from the main body part, the plurality of first tabs are stacked, the plurality of first tabs are welded to form a first welding part, the first welding part comprises a first part and a second part, and the thickness of the first part is smaller than that of the second part. The plurality of first tabs are welded on the first electrode lead-out piece and form a second welding part, and at least part of the outer periphery of the second welding part is directly connected with the first part. The direct connection position of the second welding part and the first part is not easy to crack, the first tab is not easy to crack and the like, the over-current capability between the first tab and the first electrode lead-out piece is improved, the risk of connection failure of the first tab and the first electrode lead-out piece is reduced, and the reliability of the single battery is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of batteries, and particularly relates to a battery monomer, a battery device, and a power consumption equipment. BACKGROUND

[0002] With the development of new energy technology, batteries are increasingly widely used. For example, batteries are not only applied to energy storage power systems such as hydroelectric, thermal, wind, and solar power stations, but also widely used in electric bicycles, electric motorcycles, electric vehicles, and other electric vehicles, as well as military equipment, aerospace, and other fields.

[0003] The development of battery technology needs to consider various design factors, such as energy density, cycle life, assembly efficiency, processing technology, and the reliability of the battery. SUMMARY

[0004] The embodiments of the present application provide a battery monomer, a battery device, and a power consumption equipment, which can improve the reliability.

[0005] According to a first aspect of the present application, the present application provides a battery monomer, which comprises a shell, a first electrode lead-out piece, and an electrode assembly. The first electrode lead-out piece is arranged in the shell. The electrode assembly is accommodated in the shell, and the electrode assembly comprises a main body part and a plurality of first tabs led out from the main body part. The plurality of first tabs are arranged in layers, and the plurality of first tabs are welded and form a first welding part. The first welding part comprises a first part and a second part, and the thickness of the first part is less than the thickness of the second part. The plurality of first tabs are welded to the first electrode lead-out piece and form a second welding part. At least part of the outer periphery of the second welding part is directly connected to the first part.

[0006] In the first welding part, the interlayer gap between the plurality of first tabs is compressed. The interlayer gap of the plurality of first tabs at the first part is smaller than the interlayer gap of the plurality of first tabs at the second part. The position where the second welding part is directly connected to the first part is not prone to cracks, first tab cracking, and other phenomena, which is beneficial to improve the current-carrying capacity between the first tab and the first electrode lead-out piece, reduce the risk of connection failure between the first tab and the first electrode lead-out piece, and improve the reliability of the battery monomer.

[0007] In some embodiments, the first part is a plurality of first parts, and the plurality of first parts are arranged at intervals along the outer periphery of the second welding part. In this way, the total length of the part where the outer periphery of the second welding part is directly connected to the first part can be increased, which is beneficial to reduce the size of the area between the second welding part and the first tab that is prone to cracking, further improve the current-carrying capacity between the first tab and the first electrode lead-out piece, reduce the risk of connection failure between the first tab and the first electrode lead-out piece, and improve the reliability of the battery monomer.

[0008] In some embodiments, two adjacent first portions are connected by a second portion. This reduces the area of ​​a single first portion, further decreasing the risk of the first weld portion sticking to the welding device, improving the smoothness of detachment of the first weld portion from the welding device, and further reducing the risk of tearing of the first electrode tab.

[0009] In some embodiments, the outer periphery of the second weld portion includes multiple edges connected sequentially, and at least a portion of each edge of the second weld portion is directly connected to the first portion. Therefore, cracking is less likely to occur between each edge of the second weld portion and the first electrode tab, which helps to further reduce the risk of connection failure between the first electrode tab and the first electrode lead, and improves the reliability of the battery cell.

[0010] In some embodiments, the outer periphery of the second welded portion includes multiple corner portions, each of which is directly connected to the first portion. Therefore, when the length of the portion directly connected to the first portion is limited, the risk of cracking at the corner portions and between the two edges connected by the corner portions and the first tab can be minimized, thereby improving the reliability of the battery cell.

[0011] In some embodiments, the total length of the outer periphery of the second welded portion is L1, and the total length of the portion of the outer periphery of the second welded portion directly connected to the first portion is L2, where L2 / L1 ≥ 50%. At least half of the outer periphery is directly connected to the first portion, reducing the risk of cracks or splitting, increasing the conductive area between the second welded portion and the first welded portion, improving the current-carrying capacity between the first tab and the first electrode lead, reducing heat generation, and improving the reliability of the battery cell.

[0012] In some embodiments, 75% ≤ L2 / L1 ≤ 90%. When L2 / L1 is greater than or equal to 75%, the area of ​​the easily cracked portions of the second and first welded parts is reduced, further increasing the conductive area between the second and first welded parts, thereby further improving the reliability of the battery cell. When L2 / L1 is less than or equal to 90%, the remaining portion at the outer periphery can be directly connected to the second part, which is beneficial for appropriately increasing the area of ​​the second part and reducing the risk of the first electrode tab being torn due to adhesion when the first welded part detaches from the welding device.

[0013] In some embodiments, at least a portion of the first weld portion surrounds and is directly connected to the second weld portion. This reduces necking at the junction of the second and first weld portions, further lowering the risk of cracking of the first electrode tab.

[0014] In some embodiments, the second portion is long strip-shaped in the thickness direction of the first welding portion, and the second portion is multiple, and the multiple second portions are arranged in a cross manner and form a grid structure. The distribution of the second portion and the first portion is more uniform, which not only helps to reduce the adhesion between the first welding portion and the welding device, but also helps to further reduce the cracking risk between the second welding portion and the first portion, because the distribution of the outer periphery of the second welding portion and the part directly connected with the first portion and the part not directly connected with the first portion is more uniform.

[0015] In some embodiments, a part of the second portion protrudes from the first surface of the first portion away from the first electrode lead-out piece. When the multiple first tabs and the first electrode lead-out piece are welded to form the second welding portion, the demarcation between the first portion and the second portion is easy to observe, thereby helping the outer periphery of the second welding portion to be directly connected with the first portion and improving the welding efficiency.

[0016] In some embodiments, a part of the second portion protrudes from the second surface of the first portion towards the first electrode lead-out piece; and the first welding portion forms a recess on both sides of the first portion in the thickness direction of the first welding portion. In this way, the compaction degree of the multiple first tabs on the first portion can be increased, and the interlayer gap of the multiple first tabs on the first portion is further reduced, thereby helping to further reduce the cracking risk between the first portion and the second welding portion.

[0017] In some embodiments, the interlayer gap of the multiple first tabs on the first portion is d1, the interlayer gap of the multiple first tabs on the second portion is d2, and 100≥d2 / d1≥5. This helps to reduce the risk of virtual welding and welding holes of the second welding portion, improve the welding effect and welding strength, and reduce the risk of fracture of the first tabs during welding.

[0018] In some embodiments, the interlayer gap of the multiple first tabs on the first portion is less than or equal to 3μm, which can improve the welding effect and welding strength between the multiple first tabs; and / or, the interlayer gap of the multiple first tabs on the second portion is less than or equal to 5μm, which can reduce the thickness difference between the first portion and the second portion, thereby helping to reduce the risk of fracture at the connection between the first portion and the second portion.

[0019] In some embodiments, the materials of the first tabs and the first electrode lead-out piece both include aluminum, and the effect of reducing the connection failure of the first tabs and the first electrode lead-out piece is more obvious.

[0020] In some embodiments, the first electrode lead-out piece includes a first electrode terminal, and the plurality of first tabs are welded to the first electrode terminal. The adapter piece is omitted, the impedance is reduced, the heat generation is reduced, and the power of the battery monomer is improved.

[0021] In some embodiments, the plurality of first tabs are connected by ultrasonic welding and form a first welding portion, and the plurality of first tabs and the first electrode lead-out piece are connected by laser welding and form a second welding portion. When ultrasonic welding, the first tab is less affected by heat; after welding is completed, the part of the first tab close to the first welding portion is not easy to tear. By using laser welding, the welding difficulty can be reduced, and the strength of the second welding portion formed by welding can be improved.

[0022] According to a second aspect of the present application, the present application also provides a battery device, which includes a plurality of battery monomers according to any one of the embodiments of the first aspect of the present application.

[0023] According to a third aspect of the present application, the present application also provides a power utilization device, which includes a battery device according to any one of the embodiments of the second aspect of the present application, and the battery device is used to provide electric energy. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0025] Figure 1 is a structural schematic diagram of a vehicle provided by some embodiments of the present application.

[0026] Figure 2 is an exploded structural schematic diagram of a battery device provided by some embodiments of the present application.

[0027] Figure 3 is a structural schematic diagram of a battery monomer provided by some embodiments of the present application.

[0028] Figure 4 is a sectional view schematic diagram of a battery monomer provided by some embodiments of the present application.

[0029] Figure 5 is Figure 4 is an enlarged structural schematic diagram of the region A.

[0030] Figure 6 is a sectional view schematic diagram of a plurality of first tabs and a first electrode lead-out piece of a battery monomer provided by some embodiments of the present application.

[0031] Figure 7A structure diagram of a first welding portion of a battery cell according to some embodiments of the present application.

[0032] Figure 8 A structure diagram of a first welding portion of a battery cell according to some embodiments of the present application.

[0033] Figure 9 A structure diagram of a first welding portion and a second welding portion of a battery cell according to some embodiments of the present application.

[0034] Figure 10 A structure diagram of a first welding portion and a second welding portion of a battery cell according to some embodiments of the present application.

[0035] In the drawings:

[0036] Vehicle 1, battery device 2, controller 3, motor 4, case 5, battery cell 6;

[0037] Electrode assembly 10, main body portion 11, first tab 12, bent section 121, laminated section 122, second tab 13, housing 20, shell 21, end cap 22, first electrode lead-out 30, second electrode lead-out 40, first welding portion 50, first portion 51, first surface 511, second surface 512, second portion 52, third surface 521, fourth surface 522, recess 53, first case portion 5a, second case portion 5b, accommodation space 5c, second welding portion 60, outer periphery 61, edge 62, corner portion 63, thickness direction X, first direction Y. DETAILED DESCRIPTION

[0038] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the specification herein is for describing particular embodiments only and is not intended to be limiting of the application; the use of the terms "including", "comprising" and "having" in the specification herein are meant to encompass the inclusion of one or more elements, not the exclusion of any other elements; the use of the terms "first", "second", and the like in the specification herein is intended to distinguish between similar objects, not to designate a particular order or priority of importance.

[0040] Reference to "an embodiment" or "the embodiment" in this application means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" or "in the embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive.

[0041] In the description of the application, it is necessary to point out that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "attachment" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0042] The term "and / or" in this application is only to describe the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent the following three cases: A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in this application generally represents that the front and rear associated objects have an "or" relationship.

[0043] In the embodiments of the application, the same reference signs represent the same components, and for the sake of brevity, the detailed description of the same components is omitted in different embodiments. It should be understood that the thickness, length and width of various components in the embodiments of the application shown in the drawings, as well as the overall thickness, length and width of the integrated device, are only exemplary and should not constitute any limitation on the application.

[0044] "Multiple" appearing in this application means more than two (including two).

[0045] In the embodiments of the application, "parallel" not only includes the case of absolute parallel, but also includes the case of approximate parallel which is generally recognized in engineering; at the same time, "perpendicular" also not only includes the case of absolute perpendicular, but also includes the case of approximate perpendicular which is generally recognized in engineering.

[0046] In the embodiments of the application, the battery cell can be a secondary battery cell, which refers to a battery cell that can be activated by charging after discharging to continue to use.

[0047] A battery cell generally includes a housing and an electrode assembly disposed within the housing. The electrode assembly includes a positive electrode tab and a negative electrode tab. During charging and discharging of the battery cell, active ions (e.g., lithium ions) shuttle between the positive electrode and the negative electrode. Illustratively, the electrode assembly further includes a separator disposed between the positive electrode tab and the negative electrode tab. The separator can function to prevent the positive and negative electrode tabs from shorting while allowing the active ions to pass through.

[0048] The battery cell can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium-metal battery cell, a sodium-metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-hydrogen battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc. The embodiments of the present application are not limited in this regard.

[0049] As an example, the battery cell can be a prismatic battery cell or other shaped battery cell, including a square battery cell, a blade battery cell, a multi-prismatic battery cell, such as a hexagonal prismatic battery cell, etc. The present application is not limited in this regard.

[0050] A battery device referred to in embodiments of the present application can include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly can include a plurality of battery cells connected in series, in parallel, or in a mixed connection through a busbar component.

[0051] In some embodiments, a battery cell assembly is generally formed by an arrangement of a plurality of battery cells.

[0052] A battery device generally includes a box for packaging one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

[0053] As an example, a battery cell assembly can be a battery module formed by an arrangement and fixation of a plurality of battery cells into a separate module. As an example, a battery module can be formed by bundling a plurality of battery cells with a cable tie. A battery cell assembly can be housed in a box by fixing the battery module in the box. As an example, the box can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, such that an enclosed space is formed inside the box to receive the battery cell assembly.

[0054] In some embodiments, the box can be part of a chassis structure of a vehicle. For example, part of the box can be at least part of a floor of the vehicle, or part of the box can be at least part of a cross beam and a longitudinal beam of the vehicle.

[0055] In some embodiments, a battery device can be an energy storage device. An energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0056] The battery cell generally comprises an electrode assembly, a housing, and an electrode lead-out piece. The electrode assembly is accommodated in the housing, and the electrode lead-out piece is provided on the housing. The electrode assembly comprises a tab, and the tab is connected to the electrode lead-out piece. The electrode lead-out piece can be used to electrically connect the electrode assembly with a circuit outside the battery cell to realize charging or discharging of the battery cell.

[0057] In the related art, the multiple tabs arranged in layers are first pre-welded by ultrasonic welding, and then the pre-welded multiple tabs are welded to the corresponding electrode lead-out pieces by laser welding to realize the conductive connection between the tabs and the electrode lead-out pieces. However, there are gaps between the pre-welded multiple tabs. When the tabs and the electrode lead-out pieces are laser welded, these gaps can cause welding pores, tab cracking, and the like. Cracks can occur at the edge position of the laser weld, affecting the connection stability between the tabs and the electrode lead-out pieces, and thus affecting the reliability of the battery cell.

[0058] In view of this, the embodiments of the present application provide a technical solution. At least part of the outer periphery of a second welding portion formed after the tabs and the electrode lead-out pieces are welded is directly connected with a first portion of a first welding portion formed after the multiple tabs are pre-welded. The thickness of the first portion of the first welding portion is smaller than the thickness of a second portion of the first welding portion. The interlayer gap of the multiple tabs at the first portion is smaller than the interlayer gap of the multiple tabs at the second portion. The position where the second welding portion is directly connected with the first portion is not prone to cracks and tab cracking, which is conducive to improving the overcurrent capacity between the tabs and the electrode lead-out pieces, reducing the risk of connection failure of the tabs and the electrode lead-out pieces, and improving the reliability of the battery cell.

[0059] The improved technical solution of the embodiments of the present application can be used in a battery device and an electric device using the battery device as a power supply or a variety of energy storage systems using the battery device as an energy storage element.

[0060] The electric device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric automobile, a ship, a spacecraft, and the like. The electric toy can include a fixed or mobile electric toy, such as a game console, an electric automobile toy, an electric ship toy, and an electric aircraft toy, and the like. The spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, and the like.

[0061] The following embodiments are described by taking a vehicle as an example for convenience of description.

[0062] Figure 1 A structural schematic diagram of a vehicle provided by some embodiments of the present application is shown in FIG. 1. Referring to FIG. 1, the vehicle 1 comprises a battery device 2. The battery device 2 can be arranged at the bottom, the head, or the tail of the vehicle 1. The battery device 2 can be used for power supply of the vehicle 1, for example, the battery device 2 can be used as an operating power supply of the vehicle 1. Figure 1 , the vehicle 1 comprises a battery device 2. The battery device 2 can be arranged at the bottom, the head, or the tail of the vehicle 1. The battery device 2 can be used for power supply of the vehicle 1, for example, the battery device 2 can be used as an operating power supply of the vehicle 1.

[0063] The vehicle 1 can also include a controller 3 and a motor 4, the controller 3 being configured to control the battery device 2 to supply power to the motor 4, for example, for the power requirements of the vehicle 1 during start-up, navigation and travel.

[0064] In some embodiments of the present application, the battery device 2 can not only serve as a power source for the operation of the vehicle 1, but also serve as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0065] Figure 2 A schematic diagram of the exploded structure of the battery device according to some embodiments of the present application is shown in FIG. 1. Referring to FIG. 1, the battery device 2 includes a box 5 and a battery cell 6, and the battery cell 6 is contained in the box 5. Figure 2

[0066] The box 5 is configured to contain the battery cell 6, and the box 5 can have various structures. In some embodiments, the box 5 can include a first box part 5a and a second box part 5b, the first box part 5a and the second box part 5b being mutually coverable, and the first box part 5a and the second box part 5b together defining a containing space 5c for containing the battery cell 6. The second box part 5b can be a hollow structure with one end open, and the first box part 5a can be a plate-like structure, the first box part 5a being coverable on the open end of the second box part 5b to form the box 5 with the containing space 5c. Alternatively, the first box part 5a and the second box part 5b can each be a hollow structure with one side open, the open end of the first box part 5a being coverable on the open end of the second box part 5b to form the box 5 with the containing space 5c. Of course, the first box part 5a and the second box part 5b can have various shapes, such as a cylinder, a cuboid, etc.

[0067] To improve the sealing performance of the first box part 5a and the second box part 5b after being connected, a sealing member, such as a sealing glue, a sealing ring, etc., can be provided between the first box part 5a and the second box part 5b.

[0068] Suppose the first box part 5a is coverable on the top of the second box part 5b, the first box part 5a can also be referred to as an upper box cover, and the second box part 5b can also be referred to as a lower box.

[0069] In the battery device 2, the battery cell 6 can be one or multiple. If the battery cell 6 is multiple, the multiple battery cells 6 can be connected in series, in parallel or in a mixed manner. The mixed manner means that the multiple battery cells 6 are connected in both series and parallel. The multiple battery cells 6 can be directly connected in series, in parallel or in a mixed manner, and then the whole of the multiple battery cells 6 is contained in the box 5. Of course, the multiple battery cells 6 can first be connected in series, in parallel or in a mixed manner to form a battery module, and then multiple battery modules are connected in series, in parallel or in a mixed manner to form a whole, which is contained in the box 5.​

[0070] Figure 3 A structural schematic diagram of a battery cell provided for some embodiments of the present application, Figure 4 A sectional schematic diagram of a battery cell provided for some embodiments of the present application, Figure 5 A structural schematic diagram of a battery cell provided for some embodiments of the present application, Figure 4 An enlarged structural schematic diagram of region A, Figure 6 A sectional schematic diagram of a plurality of first tabs and first electrode lead-out pieces of a battery cell provided for some embodiments of the present application, Figure 7 A structural schematic diagram of a first welding portion of a battery cell provided for some embodiments of the present application, Figure 8 A structural schematic diagram of a first welding portion of a battery cell provided for some other embodiments of the present application, Figure 9 A structural schematic diagram of a first welding portion and a second welding portion of a battery cell provided for some embodiments of the present application, Figure 10 A structural schematic diagram of a first welding portion and a second welding portion of a battery cell provided for some other embodiments of the present application.

[0071] With reference to Figures 3 to 10 , the embodiments of the present application provide a battery cell 6, which comprises a housing 20 and an electrode assembly 10 accommodated in the housing 20.

[0072] The electrode assembly 10 comprises a positive electrode and a negative electrode. During charging and discharging of the battery cell 6, active ions (e.g. lithium ions) are inserted into and extracted from the positive electrode and the negative electrode. Optionally, the electrode assembly 10 further comprises a separator arranged between the positive electrode and the negative electrode, which can reduce the risk of short circuit between the positive electrode and the negative electrode, while allowing the active ions to pass through.

[0073] The housing 20 is used to encapsulate the electrode assembly 10 and other components such as electrolyte. The housing 20 can be a steel shell, an aluminum shell, a plastic shell (e.g. polypropylene), a composite metal shell (e.g. copper-aluminum composite shell), or an aluminum-plastic film, etc.

[0074] In some embodiments, the positive electrode comprises a positive electrode sheet. The positive electrode sheet can comprise a positive electrode current collector and a positive electrode active material layer arranged on at least one surface of the positive electrode current collector.

[0075] By way of example, the positive electrode current collector has two opposite surfaces in the thickness direction of itself, and the positive electrode active material layer is arranged on either one or both of the two opposite surfaces of the positive electrode current collector.

[0076] In some embodiments, the negative electrode comprises a negative electrode sheet. The negative electrode sheet can comprise a negative electrode current collector and a negative electrode active material layer arranged on at least one surface of the negative electrode current collector.

[0077] In some embodiments, the material of the positive electrode current collector can be aluminum, and the material of the negative electrode current collector can be copper.

[0078] In some embodiments, the electrode assembly 10 further comprises a separator for separating the positive electrode sheet and the negative electrode sheet. The separator can reduce the risk of positive and negative short circuit while allowing active ions to pass through.

[0079] In some embodiments, the separator comprises a separator film. The separator film of the present application can be any known porous structure separator film with good chemical stability and mechanical stability.

[0080] In some embodiments, the electrode assembly 10 is in a roll structure. Exemplarily, both the positive electrode sheet and the negative electrode sheet are in a strip structure, and the positive electrode sheet, the separator, and the negative electrode sheet are rolled into a roll structure.

[0081] In some embodiments, the electrode assembly 10 is in a stack structure.

[0082] Exemplarily, a plurality of positive electrode sheets and a plurality of negative electrode sheets are alternately stacked.

[0083] Exemplarily, a plurality of positive electrode sheets are provided, and the negative electrode sheet is folded to form a plurality of stacked folding sections, and one positive electrode sheet is clamped between adjacent folding sections.

[0084] Exemplarily, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folding sections.

[0085] In some embodiments, the shape of the electrode assembly 10 can be cylindrical, flat, or polygonal, etc.

[0086] In some embodiments, the housing 20 comprises a shell 21 and an end cap 22, the shell 21 has an opening, and the end cap 22 is used to cover the opening.

[0087] The shell 21 is a component for cooperating with the end cap 22 to form an internal cavity of the battery cell 6, and the internal cavity formed can be used to accommodate the electrode assembly 10, the electrolyte, and other components.

[0088] The shell 21 and the end cap 22 can be independent components. Exemplarily, an opening can be provided on the shell 21, and the end cap 22 is used to cover the opening to form the internal cavity of the battery cell 6.

[0089] The shell 21 can be in various shapes and sizes, such as a cuboid, a cylinder, a hexagonal prism, etc. Specifically, the shape of the shell 21 can be determined according to the specific shape and size of the electrode assembly 10. The material of the shell 21 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, aluminum plastic film, steel plastic film, etc.

[0090] The shape of the end cover 22 can be adapted to the shape of the shell 21 to fit the shell 21. The material of the end cover 22 can be the same as or different from the material of the shell 21. Optionally, the end cover 22 can be made of a material with certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.), so that the end cover 22 is not easy to deform when subjected to extrusion and collision, and the battery monomer 6 can have higher structural strength and improved reliability.

[0091] The end cover 22 is connected to the shell 21 by welding, bonding, clamping or other means.

[0092] The shell 21 can be open at one end or both ends. In some examples, the shell 21 can be a one-side open structure, and the end cover 22 is provided as one and covers the shell 21. In other examples, the shell 21 can also be a two-side open structure, and the end cover 22 is provided as two, and the two end covers 22 cover the two openings of the shell 21 respectively.

[0093] In some embodiments, the electrode assembly 10 includes a main body 11, a first tab 12 and a second tab 13. One of the first tab 12 and the second tab 13 is a positive tab, and the other is a negative tab. The main body 11 can include a portion of a positive plate coated with an active material layer, a portion of a negative plate coated with an active material layer, and a separator. The active material in the active material layer is used to react with an electrolyte and the like to produce a charging and discharging process.

[0094] In some embodiments, the battery monomer 6 includes a first electrode lead-out piece 30 and a second electrode lead-out piece 40 provided in the outer shell 20, the first electrode lead-out piece 30 is electrically connected to the first tab 12 of the electrode assembly 10, and the second electrode lead-out piece 40 is electrically connected to the second tab 13 of the electrode assembly 10. The first electrode lead-out piece 30 and the second electrode lead-out piece 40 can be used to electrically connect the electrode assembly 10 with the circuit outside the battery monomer 6 to realize the charging and discharging of the electrode assembly 10. Exemplarily, at least part of the first electrode lead-out piece 30 and the second electrode lead-out piece 40 is exposed to the outside of the battery monomer 6 to facilitate connection with other components (such as a busbar), and then the electrical energy generated by the electrode assembly 10 is led out.

[0095] Exemplarily, the first electrode lead-out piece 30 and the second electrode lead-out piece 40 can be provided in the end cover 22 or in the shell 21.

[0096] In some embodiments, the first tab 12 extends from one end of the main body 11 facing the first electrode lead-out piece 30. The second tab 13 extends from one end of the main body 11 facing the second electrode lead-out piece 40.

[0097] In some examples, the first electrode tab 30 and the second electrode tab 40 can be located on the same side of the main body 11, or can be located on opposite sides of the main body 11, respectively.

[0098] In some embodiments, the battery cell 6 includes an electrode assembly 10, a case 20, and a first electrode tab 30. The first electrode tab 30 is provided on the case 20. The electrode assembly 10 is accommodated in the case 20, and includes a main body 11 and a plurality of first tabs 12 extending from the main body 11. The plurality of first tabs 12 are stacked, and are welded to form a first welded portion 50. The first welded portion 50 includes a first portion 51 and a second portion 52. The first portion 51 has a smaller thickness than the second portion 52. The plurality of first tabs 12 are welded to the first electrode tab 30 to form a second welded portion 60. At least a part of an outer periphery 61 of the second welded portion 60 is directly connected to the first portion 51.

[0099] In some examples, the first electrode tab 30 can include a first electrode terminal and a jumper. The electrode terminal is provided on the case 20. The jumper is connected to the first electrode terminal. The plurality of first tabs 12 and the jumper are welded to form the second welded portion 60.

[0100] In other examples, the first electrode tab 30 can include only the first electrode terminal. The plurality of first tabs 12 and the first electrode terminal are welded to form the second welded portion 60.

[0101] The first welded portion 50 and the second welded portion 60 can be formed by the same welding process, or can be formed by different welding processes.

[0102] The first welded portion 50 and the second welded portion 60 can be one or multiple.

[0103] The first portion 51 and the second portion 52 can be formed by one welding process. That is, the first portion 51 and the second portion 52 are formed by the same welding process. Alternatively, the first welded portion 50 can be formed by welding the plurality of first tabs 12 by a welding device having a welding tooth. The part in contact with the welding tooth is compacted to a greater extent, forming the first portion 51 having a smaller thickness. The part not in contact with the welding tooth is compacted to a smaller extent, forming the second portion 52 having a larger thickness. The first portion 51 and the second portion 52 are relatively flat structures without recesses or grooves.

[0104] The first welded portion 50 can be provided with a recess 53. The recess 53 is provided corresponding to the first portion 51 along the thickness direction X of the first welded portion 50. The recess 53 is formed by the first portion 51 and the second portion 52. Exemplarily, the recess 53 can be a welding groove of the first welded portion 50.

[0105] The thickness of the first portion 51 can be uniform or non-uniform. The thickness of the second portion 52 can be uniform or non-uniform. In the embodiments of the present application, the thickness of the first portion 51 is less than the thickness of the second portion 52, which means that the average thickness of the first portion 51 is less than the average thickness of the second portion 52.

[0106] The entire outer periphery 61 of the second welding portion 60 can be directly connected with the first portion 51, or only a part of the outer periphery 61 of the second welding portion 60 can be directly connected with the first portion 51, and the other part of the outer periphery 61 of the second welding portion 60 can be directly connected with the second portion 52.

[0107] The outer periphery 61 of the second welding portion 60 is a closed annular structure. Alternatively, the outer periphery 61 can be a square ring, a circular ring, an elliptical ring, or other suitable annular shapes.

[0108] After the plurality of first tabs 12 are stacked, an interlayer gap is formed between adjacent first tabs 12. After the plurality of first tabs 12 are pre-welded, the first welding portion 50 is formed, and the interlayer gap between the plurality of first tabs 12 is compressed in the first welding portion 50. The thickness of the first portion 51 is less than the thickness of the second portion 52, and the interlayer gap of the plurality of first tabs 12 in the first portion 51 is smaller than the interlayer gap of the plurality of first tabs 12 in the second portion 52. At least part of the outer periphery of the second welding portion 60 formed by welding the first tab 12 and the first electrode lead-out piece 30 is directly connected with the first portion 51, and the position where the second welding portion 60 is directly connected with the first portion 51 is not prone to cracks, cracking of the first tab 12, and other phenomena. During the working process of the battery monomer 6, the current on the first tab 12 can be conducted to the first electrode lead-out piece 30 through the first portion 51 and the second welding portion 60, which is conducive to improving the overcurrent capacity between the first tab 12 and the first electrode lead-out piece 30, reducing the risk of connection failure between the first tab 12 and the first electrode lead-out piece 30, and improving the reliability of the battery monomer 6.

[0109] In the second portion 52, the plurality of first tabs 12 are less compacted, the second portion 52 is not easy to stick together with the welding device, and the first welding portion 50 as a whole is easy to separate from the welding device, which is conducive to reducing the risk of tearing the first tab 12 when the first welding portion 50 separates from the welding device due to the large adhesion between the first welding portion 50 and the welding device.

[0110] In some embodiments, the first tab 12 includes a bending segment 121 and a stacking segment 122, the bending segment 121 is bent from one end of the stacking segment 122 and connected to the main body 11, the stacking segments 122 of the plurality of first tabs 12 are welded and form the first welding portion 50, and the stacking segments 122 of the plurality of first tabs 12 and the first electrode lead-out piece 30 are welded and form the second welding portion 60.

[0111] By bending the first tab 12, the space occupied by the first tab 12 in the thickness direction X of the first welding portion 50 can be reduced, and the space utilization can be improved.

[0112] The bent section 121 can be bent from one end of the laminated section 122 along the first direction Y. Illustratively, the first direction Y is perpendicular to the thickness direction X. Illustratively, the first direction Y can be parallel to the width direction of the end cover 22.

[0113] In some embodiments, the first portion 51 is multiple, and the multiple first portions 51 are arranged at intervals along the outer periphery of the second welding portion 60.

[0114] The multiple first portions 51 are distributed on the outer periphery of the second welding portion 60, and at least part of the multiple first portions 51 are directly connected to the outer periphery of the second welding portion 60.

[0115] The adjacent two first portions 51 can be connected by the second portion 52, or can be connected by the un-welded part of the first tab 12.

[0116] The multiple first portions 51 arranged at intervals along the outer periphery of the second welding portion 60 can increase the total length of the part of the outer periphery of the second welding portion 60 directly connected to the first portion 51, which is beneficial to reduce the size of the area at risk of cracking between the second welding portion 60 and the first tab 12, further improve the current-carrying capacity between the first tab 12 and the first electrode lead-out 30, reduce the risk of connection failure between the first tab 12 and the first electrode lead-out 30, and improve the reliability of the battery monomer 6.

[0117] In some embodiments, the adjacent two first portions 51 are connected by the second portion 52.

[0118] The second portion 52 can be multiple. Optionally, the multiple first portions 51 and the multiple second portions 52 can be arranged alternately along the outer periphery of the second welding portion 60.

[0119] The adjacent two first portions 51 connected by the second portion 52 can reduce the area of a single first portion 51, further reduce the risk of adhesion of the first welding portion 50 to the welding device, improve the smoothness of the separation of the first welding portion 50 from the welding device, and be beneficial to further reduce the risk of tearing of the first tab 12.

[0120] In some embodiments, the outer periphery 61 of the second welding portion 60 includes multiple edges 62, the multiple edges 62 are connected in sequence, and at least part of each edge 62 of the second welding portion 60 is directly connected to the first portion 51.

[0121] The edges 62 of the second welding portion 60 can extend substantially straight, and the edges 62 are sequentially connected to form a closed annular outer periphery 61. For example, the number of edges 62 can be four, and the four edges 62 are sequentially connected to form a square annular outer periphery 61. For another example, the number of edges 62 can be three, and the three edges 62 are sequentially connected to form a triangular annular outer periphery 61.

[0122] In some examples, all of the edges 62 of the second welding portion 60 are directly connected to the first portion 51.

[0123] In other examples, at least one edge 62 of the second welding portion 60 is directly connected to the first portion 51 and directly connected to the second portion 52.

[0124] At least part of each edge 62 of the second welding portion 60 is directly connected to the first portion 51, and no cracking phenomenon occurs between each edge of the second welding portion 60 and the first tab 12, which is conducive to further reducing the risk of connection failure of the first tab 12 and the first electrode lead 30 and improving the reliability of the battery monomer 6.

[0125] In some embodiments, the outer periphery of the second welding portion 60 includes a plurality of corner portions 63, and each corner portion 63 is directly connected to the first portion 51.

[0126] The number of corner portions 63 can be the same as the number of edges 62. Adjacent two edges 62 are connected through a corner portion 63.

[0127] The part of the edge 62 adjacent to the corner portion 63 is directly connected to the first portion 51.

[0128] The corner portion 63 connects adjacent two edges 62, and the corner portion 63 is directly connected to the first portion 51. In the case that the length of the part of the outer periphery 61 directly connected to the first portion 51 is limited, the risk of cracking between the corner portion 63, the two edges 62 connected through the corner portion 63, and the first tab 12 can be reduced as much as possible, and the reliability of the battery monomer 6 is improved.

[0129] In some embodiments, the total length of the outer periphery 61 of the second welding portion 60 is L1, the total length of the part of the outer periphery 61 of the second welding portion 60 directly connected to the first portion 51 is L2, and L2 / L1≥50%.

[0130] Optionally, L2 / L1 can be 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%, etc.

[0131] The outer perimeter 61 may include multiple segments, at least some of which are directly connected to multiple first parts 51, and L2 is the sum of the lengths of the segments that are directly connected to the outer perimeter 61 and the multiple first parts 51.

[0132] In this embodiment, the total length of the portion of the outer periphery 61 directly connected to the first part 51 is set to be more than half of the total length of the outer periphery 61. At least half of the outer periphery 61 is directly connected to the first part 51, which reduces the risk of cracks or splits. This is beneficial to increase the conduction area between the second welding part 60 and the first welding part 50, improve the current flow capacity between the first tab 12 and the first electrode lead-out member 30, reduce heat generation, and improve the reliability of the battery cell 6.

[0133] In some embodiments, 75% ≤ L2 / L1 ≤ 90%. Optionally, L2 / L1 can be 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, or 90%, etc.

[0134] The ratio of the total length of the portion of the outer perimeter 61 directly connected to the first part 51 to the total length of the outer perimeter 61 is greater than or equal to 75%. This reduces the area of ​​the easily cracked portions of the second welded part 60 and the first welded part 50, further increasing the conductive area between the second welded part 60 and the first welded part 50, thereby further improving the reliability of the battery cell 6. The ratio of the total length of the portion of the outer perimeter 61 directly connected to the first part 51 to the total length of the outer perimeter 61 is less than or equal to 90%. The remaining portion of the outer perimeter 61 can be directly connected to the second part 52, which helps to appropriately increase the area of ​​the second part 52 and reduces the risk of the first tab 12 being torn due to adhesion when the first welded part 50 detaches from the welding device.

[0135] In some embodiments, at least a portion of the first weld portion 50 surrounds and is directly connected to the second weld portion 60. In other words, the outer periphery of the second weld portion 60 is directly connected to the first weld portion 50.

[0136] In some examples, the first weld portion 50 and the second weld portion 60 are one, with the first weld portion 50 surrounding the second weld portion 60.

[0137] In other examples, there is one first weld portion 50 and multiple second weld portions 60, which are spaced apart. The outer periphery of each second weld portion 60 is directly connected to the first weld portion 50, and at least a portion of the outer periphery of each second weld portion 60 is directly connected to the first portion 51. A portion of the first weld portion 50 is located between adjacent second weld portions 60.

[0138] In the first welding portion 50, the interlayer gap between the plurality of first tabs 12 is small, and the outer periphery of the second welding portion 60 is directly connected to the first welding portion 50, which can weaken the necking at the junction of the second welding portion 60 and the first welding portion 50, and further reduce the risk of cracking of the first tab 12.

[0139] In addition, during the operation of the battery cell 6, the current can be directly transmitted between the first welding portion 50 and the second welding portion 60, thereby shortening the conductive path, reducing the resistance, improving the overcurrent capacity, and reducing the heat generation.

[0140] In some embodiments, the projection of the second portion 52 along the thickness direction X of the first welding portion 50 is a long strip shape, and there are a plurality of second portions 52, which are arranged in a cross shape and form a grid structure.

[0141] The grid formed by the plurality of second portions 52 arranged in a cross shape is the first portion 51. The projection of the first portion 51 along the thickness direction X can be a triangle, a rectangle, a parallelogram, or other suitable shapes.

[0142] The plurality of second portions 52 are arranged in a cross shape, and the plurality of second portions 52 and the plurality of first portions 51 can be alternately arranged according to certain rules, and the distribution of the second portion 52 and the first portion 51 is more uniform, which not only helps to reduce the adhesion between the first welding portion 50 and the welding device, but also helps to further reduce the cracking risk between the second welding portion 60 and the first portion 51.

[0143] In addition, the overall area of the long strip-shaped second portion 52 is small, which helps to increase the area of the first portion 51, thereby reducing the interlayer gap of the first tab 12 in the first welding portion 50 as a whole, and reducing the risk of cracking of the first tab 12.

[0144] In some embodiments, a part of the second portion 52 protrudes from the first surface 511 of the first portion 51 away from the first electrode lead 30.

[0145] The second portion 52 has a third surface 521 away from the first electrode lead 30, and along the thickness direction X, the third surface 521 is farther away from the first electrode lead 30 than the first surface 511.

[0146] The first portion 51 also has a second surface 512 facing the first electrode lead 30, and the second portion 52 also has a fourth surface 522 facing the first electrode lead 30. Along the thickness direction X, the second surface 512 can be substantially flush with the fourth surface 522, and the fourth surface 522 can also be closer to the first electrode lead 30 than the second surface 512.

[0147] The welding device for welding the plurality of first tabs 12 to form the first welding portion 50 can include a welding head and a welding seat oppositely arranged, the welding head facing the first surface 511 and the third surface 521, and the welding seat facing the second surface 512 and the fourth surface 522.

[0148] When only the welding head is provided with the welding teeth, the welding teeth are arranged corresponding to the first surface 511, the first surface 511 is closer to the first electrode lead-out piece 30 than the third surface 521, the side of the first portion 51 away from the first electrode lead-out piece 30 forms a recess 53, and the second surface 512 is substantially flush with the fourth surface 522.

[0149] When both the welding head and the welding seat are provided with the welding teeth, the welding teeth of the welding head and the welding seat are arranged corresponding to the first surface 511 and the second surface 512 respectively, the third surface 521 is farther away from the first electrode lead-out piece 30 than the first surface 511, the fourth surface 522 is closer to the first electrode lead-out piece 30 than the second surface 512, and both the side of the first portion 51 away from the first electrode lead-out piece 30 and the side of the first portion 51 facing the first electrode lead-out piece 30 form a recess 53.

[0150] A part of the second portion 52 protrudes from the first surface 511 of the first portion 51 in a direction away from the first electrode lead-out piece 30, and at least the side of the first portion 51 away from the first electrode lead-out piece 30 forms a recess 53. When the plurality of first tabs 12 and the first electrode lead-out piece 30 are welded to form the second welding portion 60, the boundary between the first portion 51 and the second portion 52 is easy to observe, thereby facilitating the direct connection of the outer periphery of the second welding portion 60 to the first portion 51 and improving the welding efficiency.

[0151] In some embodiments, a part of the second portion 52 protrudes from the second surface 512 of the first portion 51 facing the first electrode lead-out piece 30 in a direction facing the first electrode lead-out piece 30. The first welding portion 50 forms a recess 53 on both sides of the first portion 51 along the thickness direction X.

[0152] The recesses 53 on both sides of the first portion 51 along the thickness direction X can be of the same depth or different depths.

[0153] The second portion 52 also has a fourth surface 522 facing the first electrode lead-out piece 30, and along the thickness direction X, the fourth surface 522 is closer to the first electrode lead-out piece 30 than the second surface 512.

[0154] The first portion 51 forms a recess 53 on both sides along the thickness direction X, which can increase the compaction degree of the plurality of first tabs 12 on the first portion 51 and further reduce the interlayer gap of the plurality of first tabs 12 on the first portion 51, thereby further reducing the risk of cracking between the first portion 51 and the second welding portion 60.

[0155] In some embodiments, the interlayer gap of the plurality of first tabs 12 in the first portion 51 is d1, the interlayer gap of the plurality of first tabs 12 in the second portion 52 is d2, and 100≥d2 / d1≥5.

[0156] Optionally, d2 / d1 can be 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100.

[0157] In some embodiments, 20≥d2 / d1≥10.

[0158] In the first portion 51, the interlayer gaps of the plurality of first tabs 12 can be uniform or non-uniform. For example, the interlayer gaps between the first tabs 12 on the outer side of the plurality of first tabs 12 are relatively small, and the interlayer gaps between the first tabs 12 in the middle are relatively large. Optionally, the interlayer gaps between the plurality of first tabs 12 gradually decrease from the outside to the inside. For another example, in the arrangement direction of the second portion 52 and the first portion 51, the interlayer gaps of the plurality of first tabs 12 in the outer region of the first portion 51 close to the second portion 52 are relatively large, and the interlayer gaps of the plurality of first tabs 12 in the middle region of the first portion 51 away from the second portion 52 are relatively small.

[0159] In the embodiments of the present application, d1 is the average interlayer gap of the plurality of first tabs 12 in the first portion 51. Similarly, d2 is the average interlayer gap of the plurality of first tabs 12 in the second portion 52.

[0160] If d2 / d1 is too small, the first portion 51 is not compacted significantly, and the second welding portion 60 is prone to virtual welding, welding holes, and the like, affecting the welding effect and welding strength. If d2 / d1 is too large, the thickness difference between the first portion 51 and the second portion 52 is too large, and the first tabs 12 are prone to fracture and failure at the connection between the first portion 51 and the second portion 52.

[0161] The embodiments of the present application set the ratio of the interlayer gap of the plurality of first tabs 12 in the second portion 52 to the interlayer gap in the first portion 51 to be 5-100, which is conducive to reducing the risk of virtual welding, welding holes, and the like in the second welding portion 60, improving the welding effect and welding strength, and reducing the risk of fracture of the first tabs 12 during welding.

[0162] In some embodiments, the interlayer gap of the plurality of first tabs 12 in the first portion 51 is less than or equal to 3 μm. Optionally, d1 can be 0.1 μm, 0.5 μm, 1.0 μm, 1.5 μm, 2.0 μm, 2.5 μm, or 3.0 μm.

[0163] In the first part 51, the average gap between the plurality of first tabs 12 is too large, and the plurality of first tabs 12 can not be effectively welded, affecting the welding effect. The embodiments of the present application set the average gap of the plurality of first tabs 12 in the first part 51 to be less than or equal to 3 μm, which can improve the welding effect and welding strength between the plurality of first tabs 12.

[0164] Optionally, the interlayer gap d1 of the plurality of first tabs 12 in the first part 51 satisfies: 0.2 μm ≥ d1 ≥ 0.01 μm. In this way, the welding effect of the plurality of first tabs 12 and the structural stability of the first tab 12 can be considered.

[0165] In some embodiments, the interlayer gap of the plurality of first tabs 12 in the second part 52 is less than or equal to 5 μm. Optionally, d2 can be 0.1 μm, 0.5 μm, 1.0 μm, 1.5 μm, 2.0 μm, 2.5 μm, 3.0 μm, 3.5 μm, 4.0 μm, 4.5 μm or 5.0 μm.

[0166] In the second part 52, the average gap between the plurality of first tabs 12 is too large, the thickness of the second part 52 is too large, and the thickness difference between the second part 52 and the first part 51 is large, so the connection between the first part 51 and the second part 52 is prone to breakage. The embodiments of the present application set the average gap of the plurality of first tabs 12 in the second part 52 to be less than or equal to 5 μm, which can reduce the thickness difference between the first part 51 and the second part 52, and is conducive to reducing the risk of breakage of the connection between the first part 51 and the second part 52.

[0167] Optionally, 1 μm ≥ d2 ≥ 0.1 μm. In this way, the risk of breakage of the connection between the first part 51 and the second part 52 and the risk of tearing of the first tab 12 can be reduced at the same time.

[0168] In some embodiments, the materials of the first tab 12 and the first electrode lead-out piece 30 both include aluminum.

[0169] The first tab 12 can be a positive electrode tab.

[0170] The shrinkage rate of aluminum after solidification is large, and after welding, the necking amplitude of liquid aluminum at the interface between the first tab 12 and the molten pool is large, and the welding seam is more prone to cracking, and the risk of connection failure between the first tab 12 and the first electrode lead-out piece 30 is greater. For the first tab 12 and the first electrode lead-out piece 30 including aluminum material, the embodiments of the present application directly connect at least part of the outer periphery of the second welding part 60 with the first welding part 50, and the effect of reducing the connection failure between the first tab 12 and the first electrode lead-out piece 30 is more obvious.

[0171] In some embodiments, the first electrode lead-out piece 30 comprises a first electrode terminal, and the plurality of first tabs 12 are each welded to the first electrode terminal.

[0172] The first tabs 12 are directly welded to the first electrode terminal, which eliminates the need for a transition piece, reduces impedance, reduces heat generation, and is conducive to improving the power of the battery monomer 6.

[0173] In some embodiments, the plurality of first tabs 12 are connected by ultrasonic welding and form a first welding portion 50, and the plurality of first tabs 12 and the first electrode lead-out piece 30 are connected by laser welding and form a second welding portion 60.

[0174] When ultrasonic welding, the first tabs 12 are less affected by heat; after welding is completed, the portion of the first tabs 12 near the first welding portion 50 is not easily torn. By using laser welding, the welding difficulty can be reduced, and the strength of the second welding portion 60 formed by welding can be improved.

[0175] In some embodiments, the battery monomer 6 can be assembled according to the following steps: first, the plurality of first tabs 12 are connected by ultrasonic welding and form ultrasonic welding marks (i.e., the first welding portion 50); then, the plurality of first tabs 12 are attached to the first electrode lead-out piece 30, and laser is irradiated on the ultrasonic welding marks from the side away from the first electrode lead-out piece 30, the laser melts a portion of the first tabs 12 and a portion of the first electrode lead-out piece 30 and forms a molten pool, and the molten pool solidifies to form the second welding portion 60 (i.e., the laser welding mark).

[0176] According to some embodiments of the present application, the present application also provides a battery device 2, which comprises a plurality of battery monomers 6 provided by any one of the above embodiments.

[0177] According to some embodiments of the present application, the present application also provides a power-using device, which comprises the battery device 2 of any one of the above embodiments, and the battery device 2 is used to provide electric energy.

[0178] The embodiment of the present application provides a battery monomer 6, the battery monomer 6 includes an electrode assembly 10, a shell 20 and a first electrode terminal.The first electrode terminal is arranged in the shell 20.The electrode assembly 10 is contained in the shell 20, and the electrode assembly 10 includes a main body part 11 and a plurality of first tabs 12 led out from the main body part 11, the plurality of first tabs 12 are stacked, and the plurality of first tabs 12 are welded by ultrasonic waves and form a first welding part 50.The first welding part 50 includes a plurality of first parts 51 and a plurality of second parts 52, and the thickness of the first part 51 is less than the thickness of the second part 52.The plurality of first tabs 12 are welded to the first electrode terminal by laser and form a second welding part 60, and at least part of each edge of the second welding part 60 is directly connected with the first part 51.The plurality of first parts 51 are arranged at intervals along the outer periphery of the second welding part 60, and two adjacent first parts 51 are connected by the second part 52.The material of the first tab 12 and the first electrode lead-out piece 30 both includes aluminum.

[0179] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application. Especially, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: shell; A first electrode lead-out is provided on the outer casing; as well as An electrode assembly is housed within the housing. The electrode assembly includes a main body and a plurality of first tabs extending from the main body. The plurality of first tabs are stacked and welded together to form a first welded portion. The first welded portion includes a first part and a second part, wherein the thickness of the first part is less than the thickness of the second part. The plurality of first tabs are welded to the first electrode lead-out member to form a second welding part, and at least a portion of the outer periphery of the second welding part is directly connected to the first part.

2. The battery cell according to claim 1, characterized in that, The first part is multiple, and the multiple first parts are arranged at intervals along the outer periphery of the second welded part.

3. The battery cell according to claim 2, characterized in that, Two adjacent first parts are connected by the second part.

4. The battery cell according to any one of claims 1-3, characterized in that, The outer periphery of the second welded portion includes multiple edges that are connected sequentially, and at least a portion of each edge of the second welded portion is directly connected to the first portion.

5. The battery cell according to any one of claims 1-4, characterized in that, The outer periphery of the second welded part includes multiple corners, each of which is directly connected to the first part.

6. The battery cell according to any one of claims 1-5, characterized in that, The total length of the outer periphery of the second welded part is L1, and the total length of the portion of the outer periphery of the second welded part that is directly connected to the first part is L2, where L2 / L1≥50%.

7. The battery cell according to claim 6, characterized in that, 75% ≤ L2 / L1 ≤ 90%.

8. The battery cell according to any one of claims 1-7, characterized in that, At least a portion of the first welded portion surrounds the second welded portion and is directly connected to the second welded portion.

9. The battery cell according to any one of claims 1-8, characterized in that, Along the thickness direction of the first welded part, the projection of the second part is a strip shape, and there are multiple second parts, which are intersected and form a grid structure.

10. The battery cell according to any one of claims 1-9, characterized in that, A portion of the second part protrudes from the first surface of the first part opposite to the first electrode lead in a direction away from the first electrode lead.

11. The battery cell according to claim 10, characterized in that, A portion of the second part protrudes from the second surface of the first part facing the first electrode lead in a direction toward the first electrode lead; Along the thickness direction of the first welded portion, the first welded portion has recesses on both sides of the first portion.

12. The battery cell according to any one of claims 1-11, characterized in that, The interlayer gap of the plurality of first electrodes in the first part is d1, and the interlayer gap of the plurality of first electrodes in the second part is d2, where 100≥d2 / d1≥5.

13. The battery cell according to any one of claims 1-12, characterized in that, The interlayer gap between the plurality of first tabs in the first portion is less than or equal to 3 μm; and / or The interlayer gap between the plurality of first tabs in the second part is less than or equal to 5 μm.

14. The battery cell according to any one of claims 1-13, characterized in that, The materials of the first tab and the first electrode lead-out are both aluminum.

15. The battery cell according to any one of claims 1-14, characterized in that, The first electrode lead includes a first electrode terminal, and the plurality of first tabs are soldered to the first electrode terminal.

16. The battery cell according to any one of claims 1-15, characterized in that, The plurality of first electrodes are connected by ultrasonic welding to form the first welded part, and the plurality of first electrodes and the first electrode lead-out are connected by laser welding to form the second welded part.

17. A battery device, characterized in that, It includes multiple battery cells according to any one of claims 1-16.

18. An electrical appliance, characterized in that, Includes the battery device according to claim 17, the battery device being used to provide electrical energy.

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