Battery monomer, battery and electric device

Abstract

The utility model discloses a battery monomer (20), a battery (1100) and a power utilization device, the battery monomer (20) comprises a shell (100) and an end cover (200), and the shell (100) is provided with an opening; the end cover (200) is welded at the opening and forms a welding structure (300), the welding structure (300) comprises a plurality of first welding seams (310), the first welding seams (310) and the edge part (210) of the end cover (200) are correspondingly arranged, and the plurality of first welding seams (310) are connected to form a closed annular structure so as to be annularly arranged outside the end cover (200); every two adjacent first welding seams (310) are connected in a laminated mode at the corresponding corner (220) of the end cover (200). According to the battery monomer (20), the strength of the welding structure (300) at the corner (220) of the end cover (200) is good, the strength of the welding structure (300) between the shell (100) and the end cover (200) is good, the welding quality is high, and the structural reliability of the battery monomer (20) is good.

Description

Technical Field

[0001] This application relates to the field of welding technology, specifically to a battery cell, a battery, and an electrical device. Background Technology

[0002] A single battery cell includes components such as a casing, electrode assembly, and end caps. The end caps are welded to the opening of the casing, forming a sealed space with the casing. The electrode assembly is located in this sealed space and undergoes electrochemical reactions, thereby realizing the charging and discharging of the battery. However, the welded structure between the casing and the end cap has poor strength at the corners of the end caps. Summary of the Invention

[0003] The purpose of this application is to provide a battery cell, a battery, and an electrical device, including but not limited to solving the problem of poor strength of the welded structure between the casing and the end cap at the corner of the end cap.

[0004] The technical solution adopted in the embodiments of this application is:

[0005] In a first aspect, a battery cell is provided, the battery cell including a housing and an end cap, the housing having an opening; the end cap is welded to the opening and forms a welding structure, the welding structure including a plurality of first welds, the first welds being disposed corresponding to the edges of the end cap, the plurality of first welds being connected to form a closed annular structure surrounding the end cap; wherein, two adjacent first welds are stacked and connected at the corresponding corners of the end cap.

[0006] In the battery cell of this application embodiment, two adjacent first welds are stacked at the corner of the end cover, so that the corner of the end cover is welded at least twice, and at least two overlapping welds are formed at the corner of the end cover. The overlapping of the two welds reduces welding defects at the corner of the end cover, thereby increasing the welding structure strength at the corner of the end cover. The welding structure between the shell and the end cover has good strength, high welding quality, and good structural reliability of the battery cell.

[0007] In one embodiment, in the width direction of the first weld, two adjacent first welds partially overlap at the corner of the end cap.

[0008] In the battery cell of this application embodiment, the first weld seam overlaps and covers the end cap, and the welding area between the end cap and the shell is large, resulting in better welding reliability.

[0009] In one embodiment, in two adjacent first welds, the starting end of one first weld is stacked with the ending end of the other first weld.

[0010] In this embodiment of the battery cell, the corner of the end cap is used as the welding start position. In this way, the weld material formed by welding will accumulate at the molten pool at the welding end position, thereby improving the welding quality and welding strength at the welding end position.

[0011] In one embodiment, the lowest point of the molten pool of the first weld is located inside the end cap.

[0012] In the battery cell of this application embodiment, the lowest point of the molten pool of the first weld is located inside the end cap, so that the casing will not be welded through during welding and cause leakage. This results in good sealing performance between the casing and the end cap after welding, improving the reliability of the battery cell.

[0013] In one embodiment, the depth of the weld pool at the corner of the end cap is greater than the depth of the weld pool at other locations of the weld structure.

[0014] The battery cells in this application have high welding quality, good weld strength between the casing and the end cap, and good reliability in use.

[0015] In one embodiment, at least one first weld includes a first weld segment and a second weld segment connected together, the first weld segment and the second weld segment being distributed along the length direction of the corresponding side of the end cap.

[0016] In the battery cell of this application embodiment, the first weld segment and the second weld segment can be welded in two steps to obtain the first weld, making the welding operation between the shell and the end cap simpler and more convenient.

[0017] In one embodiment, the ends of the first weld segment and the second weld segment that are close to each other are stacked together.

[0018] In the battery cell of this application embodiment, the connection between the first weld segment and the second weld segment is welded at least twice. This increases the welding strength at the connection between the first weld segment and the second weld segment, reduces welding defects, improves the welding quality between the end cap and the casing, and improves the reliability of the battery cell.

[0019] In one embodiment, the length of the first weld segment is greater than the stack length of two adjacent first welds, and the length of the second weld segment is greater than the stack length of two adjacent first welds.

[0020] The battery cell in this embodiment can reduce the connection between the first weld segment and the second weld segment at the corner of the end cover, thereby improving the welding strength and welding quality at the corner of the end cover.

[0021] In one embodiment, the end point of the first weld segment is stacked with the end point of the second weld segment.

[0022] The battery cell of this application embodiment can reduce the problem of insufficient molten pool caused by the welding of two adjacent first welds ending at the same corner of the end cover. The end cover and the shell have good welding quality and good welding structure strength at the corner of the end cover.

[0023] In one embodiment, in the width direction of the first weld segment, the end portions of the first weld segment and the second weld segment that are relatively close to each other are stacked together.

[0024] In the battery cell of this application embodiment, the first weld segment and the second weld segment partially overlap and cover each other, resulting in a large welding area between the end cap and the shell and better welding reliability.

[0025] In one embodiment, the welded structure further includes at least one second weld that extends from the end of the first weld toward the beginning of the first weld and covers the first weld.

[0026] The battery cell of this application embodiment can improve the welding quality and welding structure strength at the corner of the end cap.

[0027] In one embodiment, the starting end of the second weld overlaps the ending end of the first weld.

[0028] In the battery cell of this application embodiment, the welding material at the starting end of the second weld can accumulate to fill the molten pool at the ending end of the first weld, thereby further improving the welding quality and welding structure strength at the corner of the end cap.

[0029] In one embodiment, in the width direction of the first weld, the second weld portion covers the first weld.

[0030] In the battery cell of this application embodiment, the second weld and the first weld partially overlap and cover each other, the welding area between the end cap and the shell is large, and the welding reliability is better.

[0031] In one embodiment, at least one pair of opposing first welds is covered by a second weld.

[0032] In the battery cell of this application embodiment, during welding, two welding heads are used to weld the opposite sides of the end cap respectively. After the two welding heads are welded in the same direction to obtain two oppositely arranged first welds, they are moved in opposite directions for a certain distance to obtain a pair of second welds. By controlling the two welding heads to move back and forth synchronously in the same direction, the welding is easy to achieve and convenient for processing and manufacturing.

[0033] In one embodiment, in two adjacent first welds, the end of one first weld is stacked with the end of the other first weld, and the end of at least one first weld is covered by the beginning of a second weld.

[0034] In the battery cell of this application embodiment, the second weld is used to fill the molten pool at the corner to overcome welding defects such as insufficient molten pool, thereby improving the strength and quality of the welded structure.

[0035] In one embodiment, the length of the second weld is greater than the stack length of two adjacent first welds.

[0036] The battery cell of this application embodiment can effectively improve the welding structure strength and welding quality at the corner of the end cap.

[0037] In one embodiment, the length of the first weld is greater than the length of the second weld.

[0038] The battery cell in this embodiment has a moderate welding length, which is beneficial to improving production efficiency and reducing welding costs.

[0039] In one embodiment, the first weld includes a first corner segment, a first connecting segment, a second connecting segment, and a second corner segment connected in sequence. The first corner segment and the second corner segment are located at two adjacent corners of the end cap, and the second weld covers the second connecting segment and the second corner segment. The molten pool depth of the welded structure on the second corner segment is greater than the molten pool depth of the welded structure on the second connecting segment, and the molten pool depth of the welded structure at the second connecting segment is greater than the molten pool depth of the welded structure on the first connecting segment.

[0040] The battery cell in this embodiment has a deep molten pool and good welding reliability, which also ensures good welding strength at the corner near the end cap, thus improving the welding reliability between the end cap and the casing.

[0041] In one embodiment, the lowest point of the molten pool of the second weld is located inside the end cap.

[0042] In the battery cell of this application embodiment, the casing will not be welded through during welding, thus preventing leakage. This ensures good sealing performance between the casing and the end cap after welding, improving the reliability of the battery cell.

[0043] In one embodiment, the welded structure is located on the side of the end cap.

[0044] The battery cells in this embodiment are simple and convenient to weld, and easy to implement.

[0045] In one embodiment, the corner of the end cap is arc-shaped.

[0046] The battery cell of this application embodiment can make the transition of the edge of the battery cell smoother, improve the reliability of the battery cell, and facilitate welding.

[0047] In one embodiment, the end cap is configured with a protrusion that inserts into the housing through an opening.

[0048] The battery cell in this embodiment enables the end cap to be stably fixed to the housing, thereby improving the subsequent welding accuracy.

[0049] In one embodiment, the distance between the outer peripheral wall of the protrusion and the outer peripheral wall of the end cap ranges from 0.1 mm to 0.5 mm.

[0050] The battery cell in this application embodiment allows the casing and end cap to be stably and reliably welded together, resulting in a strong welded structure.

[0051] Secondly, a battery is provided, comprising the aforementioned battery cell.

[0052] The battery in this application embodiment uses the above-mentioned battery cell. The welding structure between the casing and the end cap of the battery cell has good strength, the battery cell has good reliability, and the battery has better reliability and performance.

[0053] Thirdly, an electrical device is provided, including the battery described above.

[0054] The electrical device in this application uses the aforementioned battery, which has good reliability and performance, and also helps to improve the performance and reliability of the electrical device. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or exemplary technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1 This is a schematic diagram of the structure of a vehicle provided in one embodiment of this application.

[0057] Figure 2 This is a schematic diagram of the structure of a battery provided in one embodiment of this application.

[0058] Figure 3 This is a schematic diagram of the structure of a battery cell provided in one embodiment of this application.

[0059] Figure 4 This is an exploded structural diagram of a battery cell provided in an embodiment of this application.

[0060] Figure 5 This is a schematic diagram of the structure of a battery cell provided in one embodiment of this application from another perspective.

[0061] Figure 6 This is a schematic diagram of the welding structure of a battery cell provided in an embodiment of this application.

[0062] Figure 7 For use in making Figure 6A schematic diagram of the welding equipment for the welding structure shown.

[0063] Figure 8 for Figure 7 The diagram shows the welding process of the welding equipment at the first welding station.

[0064] Figure 9 for Figure 7 The diagram shows the welding process of the welding equipment at the second welding station.

[0065] Figure 10 for Figure 7 The diagram shows the welding equipment used at the first welding station.

[0066] Figure 11 This is a partial cross-sectional view of a battery cell provided in an embodiment of this application.

[0067] Figure 12 A partial cross-sectional view of the welding structure of a battery cell provided in an embodiment of this application at the first weld.

[0068] Figure 13 This is a schematic diagram of the welding structure of a battery cell provided in an embodiment of this application.

[0069] Figure 14 This is a schematic diagram of the welding equipment for the welding structure of a battery cell provided in an embodiment of this application.

[0070] Figure 15 for Figure 14 The diagram shows the welding process of the welding equipment at the first welding station.

[0071] Figure 16 for Figure 14 The diagram shows the welding process of the welding equipment at the second welding station.

[0072] Figure 17 For use in making Figure 13 The welding equipment shown is used for welding at the second welding station.

[0073] Figure 18 for Figure 17 A magnified view of a portion of point A in the middle.

[0074] Figure 19 A partial cross-sectional view of the welding structure of a battery cell provided in an embodiment of this application at the overlapping point of the first welding segment and the second weld segment.

[0075] Figure 20 This is a schematic diagram of the welding structure of a battery cell provided in an embodiment of this application.

[0076] Figure 21For use in making Figure 20 The welding equipment shown is used for welding at the second welding station.

[0077] Figure 22 for Figure 17 A magnified view of a section at point F.

[0078] Figure 23 This is a partial cross-sectional view of a battery cell provided in an embodiment of this application.

[0079] The following are the labeling elements in the figure:

[0080] 1000, Vehicle; 1100, Battery; 1200, Controller; 1300, Motor; 10, Housing; 11, First Part; 12, Second Part; 20, Battery Cell;

[0081] 100. Shell;

[0082] 200. End cap;

[0083] 210. Edge; 220. Corner; 230. Protrusion;

[0084] 241. Electrode terminals; 242. Pressure relief mechanism;

[0085] 300. Welded structure;

[0086] 310. First weld; 320. Second weld; 330. Molten pool;

[0087] 3111, First weld segment; 3112, Second weld segment;

[0088] 3121. First corner segment; 3122. First connecting segment; 3123. Second connecting segment; 3124. Second corner segment;

[0089] 3101. Starting point; 3102. Ending point;

[0090] 400. Welding joint;

[0091] 500. Welding equipment;

[0092] 510. Assembly station; 520. First welding station; 530. First trimming station; 540. Transfer station; 550. Second welding station; 560. Second trimming station; 570. Conveying mechanism;

[0093] 600. Electrode assembly. Detailed Implementation

[0094] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0095] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0096] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0097] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0098] In the description of this application, it should be noted that the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0099] It should also be noted that in the embodiments of this application, the same reference numerals are used to represent the same component or part. For the same part in the embodiments of this application, the reference numerals may only be used to mark one part or component as an example. It should be understood that the reference numerals are also applicable to other identical parts or components.

[0100] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0101] In this application, for ease of description, the Z-axis in the accompanying drawings represents the up-down direction, with the positive direction of the Z-axis representing up and the negative direction of the Z-axis representing down. The Y-axis in the accompanying drawings represents the left-right direction, with the positive direction of the Y-axis representing left and the negative direction of the Y-axis representing right. The X-axis in the accompanying drawings represents the front-back direction, with the positive direction of the X-axis representing back and the negative direction of the X-axis representing front.

[0102] Currently, judging from market trends, the application of batteries is becoming increasingly widespread. Batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of the application areas of power batteries, the market demand for them is also constantly increasing.

[0103] A single battery cell includes components such as a casing, electrode assembly, and end caps. The end caps are welded to the opening of the casing, forming a sealed space with the casing. The electrode assembly is located in this sealed space and undergoes electrochemical reactions, thereby realizing the charging and discharging of the battery. However, the welded structure between the casing and the end caps has poor strength.

[0104] The applicant discovered that one of the main reasons for the poor weld strength between the shell and the end cap was that poor welding easily occurred at the corners of the end cap during the welding process, leading to welding defects and consequently poor weld strength. Even after increasing the welding power and improving the weld pool depth, the weld strength problem persisted. Further research revealed that poor welding was particularly prone to occur at the corners of the end cap.

[0105] Therefore, in order to improve the welding strength between the casing and the end cap, the applicant, after in-depth research, designed a battery cell in which the end cap and casing are provided with at least two welds stacked at the corner of the end cap. This increases the welding strength at the corner, improves the welding quality of the battery cell, and enhances the structural strength of the battery, which is beneficial to improving the reliability of the battery.

[0106] The battery cell, battery, and electrical device using the battery as a power source disclosed in this application can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0107] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0108] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. A battery 1100 is disposed inside the vehicle 1000, and the battery 1100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 1100 can be used to power the vehicle 1000; for example, the battery 1100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 1200 and a motor 1300. The controller 1200 is used to control the battery 1100 to supply power to the motor 1300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0109] In some embodiments of this application, the battery 1100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0110] Please refer to Figure 2As one embodiment of the battery 1100, the battery 1100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the battery housing 10. The battery housing 10 provides a space for the battery cell 20 and can adopt various structures. In some embodiments, the battery housing 10 may include a first portion 11 and a second portion 12, which overlap each other, jointly defining a space for accommodating the battery cell 20. The second portion 12 may be a hollow structure with one open end, and the first portion 11 may be a plate-like structure, covering the open side of the second portion 12 so that the first portion 11 and the second portion 12 jointly define the space; alternatively, the first portion 11 and the second portion 12 may both be hollow structures with one open side, with the open side of the first portion 11 covering the open side of the second portion 12. Of course, the battery housing 10 formed by the first portion 11 and the second portion 12 can be of various shapes, such as a cylinder, a cuboid, etc.

[0111] In battery 1100, there can be multiple battery cells 20. Multiple battery cells 20 can be connected in series, in parallel, or in a mixed manner. A mixed manner means that multiple battery cells 20 are connected in both series and parallel.

[0112] In one embodiment, multiple battery cells 20 can be directly connected in series, parallel, or in a hybrid configuration, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery 1100 can also be formed by first connecting multiple battery cells 20 in series, parallel, or in a hybrid configuration to create a battery module, and then connecting multiple battery modules in series, parallel, or in a hybrid configuration to form a whole, which is then housed within the housing 10. The battery 1100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0113] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 20 can be flat, cuboid, or other shapes.

[0114] As another embodiment of the battery 1100, the battery 1100 may not include the housing 10, but instead connect multiple battery cells 20 electrically and assemble them into an electrical device after forming a whole through necessary fixing structures.

[0115] Please refer to Figure 3 and Figure 4 , Figure 3 This is a schematic diagram of the structure of a battery cell 20 provided in some embodiments of this application. Figure 4This is an exploded structural diagram of a battery cell 20 provided in some embodiments of this application. The battery cell 20 refers to the smallest unit that makes up a battery. Figure 3 The battery cell 20 includes an end cap 200, a housing 100, an electrode assembly 600, and other functional components.

[0116] End cap 200 refers to a component that covers the opening of housing 100 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 200 can be adapted to the shape of housing 100 to fit it. Optionally, end cap 200 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 200 is not easily deformed under pressure and impact, giving battery cell 20 higher structural strength and improved safety performance. Functional components such as electrode terminals 241 can be provided on end cap 200. Electrode terminals 241 can be used for electrical connection with electrode assembly 600 to output or input electrical energy to battery cell 20. In some embodiments, end cap 200 can also be provided with a pressure relief mechanism 242 for releasing internal pressure when the internal pressure or temperature of battery cell 20 reaches a threshold. The material of end cap 200 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, an insulating element may be provided on the inner side of the end cap 200. The insulating element can be used to isolate the electrical connection components within the housing 100 from the end cap 200 to reduce the risk of short circuits. For example, the insulating element may be made of plastic, rubber, etc.

[0117] The housing 100 is an assembly used to cooperate with the end cap 200 to form the internal environment of the battery cell 20, wherein the formed internal environment can accommodate the electrode assembly 600, electrolyte, and other components. The housing 100 and the end cap 200 can be independent components, with an opening provided on the housing 100. The end cap 200 closes the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 200 and the housing 100 can be integrated. Specifically, the end cap 200 and the housing 100 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 100, the end cap 200 closes the housing 100. The housing 100 can have various shapes and sizes, such as cuboid, cylindrical, or hexagonal prism. Specifically, the shape of the housing 100 can be determined according to the specific shape and size of the electrode assembly 600. The shell 100 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special restrictions on this.

[0118] Electrode assembly 600 is the component in the battery cell 20 where electrochemical reactions occur. The housing 100 may contain one or more electrode assemblies 600. Electrode assembly 600 includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of the battery cell 20, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, reduces short circuits between them while allowing active ions to pass through.

[0119] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0120] In some embodiments, the negative electrode may be a negative electrode sheet, which may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0121] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0122] In some embodiments, the electrode assembly 600 is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0123] In some embodiments, the electrode assembly 600 has a stacked structure.

[0124] like Figure 5 and Figure 6 As shown, in one embodiment of this application, a battery cell 20 is provided, which includes a housing 100 and an end cap 200. The housing 100 has an opening. The end cap 200 is welded to the opening and forms a welding structure 300. The welding structure 300 includes a plurality of first welds 310. The first welds 310 are correspondingly disposed with the edge 210 of the end cap 200. The plurality of first welds 310 are connected to form a closed annular structure surrounding the end cap 200. Adjacent first welds 310 are stacked and connected at the corner 220 of the end cap 200.

[0125] End cap 200 refers to a component that covers the opening of housing 100, such as the aforementioned component used to cover the opening of housing 100 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 200 also matches the shape of the opening of housing 100; the shape of end cap 200 can be a polygon such as a triangle, quadrilateral, or pentagon. For example, combined with... Figure 5 As shown, the end cap 200 is rectangular in shape.

[0126] The housing 100 refers to the outer protective component of the battery cell 20, such as the component described above that is used to cooperate with the end cap 200 to form the internal environment of the battery cell 20.

[0127] The end cap 200 is welded to the opening and forms a welded structure 300. It can be understood that the edge 210 of the end cap 200 is welded to the edge corresponding to the opening of the housing 100, thereby connecting the housing 100 and the end cap 200 into a whole. The welded structure 300 refers to the connecting part formed after the edge 210 of the end cap 200 is welded to the edge corresponding to the opening of the housing 100.

[0128] The welded structure 300 includes multiple first welds 310, which are correspondingly provided with the edges 210 of the end cap 200. It can be understood that the first weld 310 refers to the weld formed after the edge 210 of the end cap 200 is welded to the edge 210 corresponding to the opening of the housing 100. The number of first welds 310 is the same as the number of edges 210 of the end cap 200; for example... Figure 6 and Figure 13 As shown, the end cap 200 is rectangular, and each of its four sides 210 has a corresponding first weld 310, meaning there are four first welds 310. The welding structures 300 at the four sides 210 of the end cap 200 correspond to the first welds 310 located on the front, rear, left, and right sides of the figure, respectively. The welding structures 300 at the four corners 220 of the end cap 200 can be found in [reference needed]. Figure 6 and Figure 13 The weld structures at the four corners are arranged at an angle; the specific correspondence can be found by referring to the directions indicated by the solid arrows in the diagram. It should be noted that, for ease of illustration, [the specific details are missing here]. Figure 6 and Figure 13 The welded structure 300 is divided into 6 segments. The starting end 3101 and the ending end 3102 of the first weld 310 are disconnected from the first weld 310 and are located in two inclined weld structures respectively. However, in the actual product, the 6 welded structures 300 in the figure are connected end to end in sequence. That is, the starting end 3101 and the ending end 3102 of the first weld 310 are connected together with the first weld 310. The welded structure 300 is formed by four first welds 310 stacked end to end to form a ring welded structure around the end cap 200.

[0129] Of course, in another embodiment, the end cap 200 is triangular, and each of the three sides 210 of the end cap 200 is provided with a first weld 310, that is, the number of first welds 310 is three. Of course, in other embodiments, the end cap 200 can also be pentagonal, hexagonal, etc.

[0130] Multiple first welds 310 are connected to form a closed annular structure surrounding the end cap 200; it can be understood that multiple first welds 310 are connected end to end to form a closed annular structure, thereby surrounding the end cap 200, thereby achieving an overall sealed connection between the end cap 200 and the housing 100.

[0131] The corner 220 of the end cap 200 refers to the connection point of two adjacent sides 210 on the end cap 200 (combination). Figure 6 (As shown).

[0132] Two adjacent first welds 310 are stacked and connected at the corner 220 of the end cap 200. This means that at the connection point of two adjacent first welds 310, one first weld 310 overlaps the other, forming a weld stack structure located at the corner 220 of the end cap 200. During welding, welding the side 210 connected to the corner 220 will weld to the corner 220, forming one layer of weld in the weld stack structure. Similarly, welding the other side 210 connected to the corner 220 will also weld to the corner 220, forming another layer of weld in the weld stack structure. In other words, the corner 220 of the end cap 200 will be welded at least twice, forming at least two welds. It should be noted that either all two adjacent first welds 310 may be stacked and connected at the corner 220 corresponding to the end cap 200, or only some two adjacent first welds 310 may be stacked and connected at the corner 220 corresponding to the end cap 200.

[0133] In this embodiment of the application, the battery cell 20 has two adjacent first welds 310 stacked at the corner 220 of the end cover 200, so that the corner 220 of the end cover 200 is welded at least twice, and at least two overlapping welds are formed at the corner 220 of the end cover 200. The overlapping of the two welds reduces the welding defects at the corner 220 of the end cover 200, thereby increasing the welding structural strength at the corner 220 of the end cover 200. The welding structural strength between the shell 100 and the end cover 200 is good, the welding quality is high, and the structural reliability of the battery cell 20 is good.

[0134] In another embodiment of this application, the provided battery cell 20 has two adjacent first welds 310 partially overlapping at the corner 220 of the end cap 200 in the width direction of the first weld 310.

[0135] In the width direction of the first weld 310, for example Figure 10 As shown, the width direction of the first weld 310 is the Z direction.

[0136] In the width direction of the first weld 310, two adjacent first welds 310 partially overlap at the corner 220 of the end cap 200. It is understandable that during the welding process, due to processing errors, the center line B of the welding head 400 when welding the two adjacent edges 210 of the end cap 200 is not on the same horizontal plane. As a result, the center lines of the two adjacent first welds 310 are not on the same horizontal plane, which in turn causes the two adjacent first welds 310 to be misaligned vertically. This results in the two adjacent first welds 310 not completely overlapping and covering each other, but partially overlapping and covering each other. In addition, with partial overlap and covering, the welding area between the end cap 200 and the shell 100 is larger, and the welding reliability is better.

[0137] In another embodiment of this application, combined with Figure 6 As shown, in the provided battery cell 20, in two adjacent first welds 310, the starting end 3101 of one first weld 310 is stacked and connected to the ending end 3102 of the other first weld 310.

[0138] The starting end 3101 of the first weld 310 refers to the section of weld formed at the beginning of welding the edge 210 of the end cap 200.

[0139] The end point 3102 of the first weld 310 refers to the section of weld formed when the edge 210 of the end cap 200 is almost finished being welded.

[0140] Please refer to Figure 6 and Figure 13 In two adjacent first welds 310, the starting end 3101 of one first weld 310 is stacked and connected to the ending end 3102 of the other first weld 310. It can be understood that at the corner 220 of the end cap 200, the starting end 3101 of one first weld 310 is stacked and connected to the ending end 3102 of the other first weld 310. That is to say, the corner 220 of the end cap 200 is both the welding start position of one first weld 310 and the welding end position of another first weld 310. This can reduce welding defects such as insufficient molten pool 330 caused by the welding of two adjacent first welds 310 ending at the same corner 220 of the end cap 200. In addition, since the corner 220 of the end cap 200 is the welding start position, the weld material formed by welding will accumulate at the molten pool 330 at the welding end position, thereby improving the welding quality and welding strength at the welding end position. It should be noted that all two adjacent first welds 310 may be connected by a stacked connection of the starting end 3101 and the ending end 3102 at the corner 220 corresponding to the end cap 200, or some two adjacent first welds 310 may be connected by a stacked connection of the starting end 3101 and the ending end 3102 at the corner 220 corresponding to the end cap 200.

[0141] In another embodiment of this application, combined with Figure 12 As shown, the lowest point C of the molten pool 330 of the first weld 310 of the provided battery cell 20 is located inside the end cap 200.

[0142] The molten pool 330 refers to the liquid metal portion with a certain geometric shape formed on the shell 100 and end cap 200 under the action of the welding heat source; wherein, the molten pool 330 can also be the portion formed after the liquid metal portion has solidified.

[0143] The lowest point of the molten pool 330 in the first weld 310 refers to the lowest point C of the molten pool 330 in its depth direction, for example... Figure 12 As shown, the depth direction of the molten pool 330 can be the X direction.

[0144] In this embodiment of the application, when the battery cell 20 is welded from the side of the end cover 200, the lowest point of the molten pool 330 of the first weld 310 is located inside the end cover 200. This prevents the housing 100 from being welded through during welding, thus preventing leakage. This results in good sealing performance between the housing 100 and the end cover 200 after welding, improving the reliability of the battery cell 20.

[0145] In another embodiment of this application, the depth of the molten pool 330 at the corner 220 of the end cap 200 of the provided battery cell 20 is greater than the depth of the molten pool 330 at other parts of the welding structure 300.

[0146] In this embodiment of the battery cell 20, the depth of the molten pool 330 at the corner 220 of the end cap 200 is greater than the depth of the molten pool 330 at other parts, the welding structure 300 at the corner 220 of the end cap 200 has good reliability and high welding quality, the welding structure between the shell 100 and the end cap 200 has good strength, and the battery cell 20 has good reliability in use.

[0147] In one embodiment, combined with Figures 6-9 As shown, the end cap 200 is rectangular, with two long sides and two short sides. The housing 100 is cuboid. When welding the end cap 200 and the housing 100 using welding equipment 500, the welding equipment 500 includes a conveying mechanism 570. The conveying mechanism 570 is sequentially arranged along the conveying direction with an assembly station 510, a first welding station 520, a first trimming station 530, a transfer station 540, a second welding station 550, and a second trimming station 560 (in combination). Figure 7 (As shown).

[0148] During welding, firstly, the end cap 200, electrode assembly 600 and housing 100 are assembled at the assembly station 510, so that the end cap 200 covers the opening of the housing 100 and is fixed in the first fixture with the end cap 200 facing downward. The first fixture allows the long side of the end cap 200 to be exposed to facilitate welding of the long side. Then, the conveying mechanism 570 moves the first fixture and the housing 100 and end cap 200 fixed in the first fixture to the first welding station 520.

[0149] Then, the two welding heads 400 respectively weld the two long sides from opposite sides of the end cap 200, and the two welding heads 400 move in opposite directions. The welding head 400 located on the rear side moves from left to right to obtain the first weld 310 located on the rear side, with the left end of the first weld 310 being the starting end 3101 and the right end being the ending end 3102. The welding head 400 located on the front side moves from right to left to obtain the first weld 310 located on the front side, with the left end of the first weld 310 being the ending end 3102 and the right end being the starting end 3101.

[0150] Afterwards, the conveying mechanism 570 continues to move the first clamp, end cap 200 and housing 100 to the first trimming station 530. After the first trimming station 530 trims the first weld 310 on the long side, the conveying mechanism 570 continues to move the first clamp, end cap 200 and housing 100 to the transfer station 540.

[0151] Then, at the intermediate station 540, the end cap 200 and the housing 100 are moved into the second fixture so that the two short sides of the end cap 200 are exposed, thereby facilitating welding at the short sides.

[0152] Subsequently, the conveying mechanism 570 continues to move the second clamp, housing 100, and end cap 200 together to the second welding station 550. At the second welding station 550, two welding heads 400 weld the two short sides of the end cap 200 from opposite sides, and the two welding heads 400 move in opposite directions. The welding head 400 on the left moves from back to front to form the first weld 310 on the left side. The front end of the first weld 310 is the starting end 3101, and the rear end is the ending end 3102. The ending end 3102 of the first weld 310 on the left side and the starting end 3101 of the first weld 310 on the rear side are stacked and connected at the corner 220 on the left rear side of the end cap 200. The starting end 3101 of the first weld 310 on the left side and the starting end 3101 of the first weld 310 on the front side are stacked and connected. The end point 3102 of the first weld 310 is stacked and connected at the corner 220 on the left front side of the end cap 200; while the welding head 400 on the right side moves from back to front to obtain the first weld 310 on the right side, the front end of which is the end point 3102 and the rear end is the starting point 3101; and the starting point 3101 of the first weld 310 on the right side and the end point 3102 of the first weld 310 on the rear side are stacked and connected at the corner 220 on the right rear side of the end cap 200, and the end point 3102 of the first weld 310 on the right side and the starting point 3101 of the first weld 310 on the front side are stacked and connected at the corner 220 on the right front side of the end cap 200; in this way, the moving directions of the four welding heads 400 form a clockwise rotating ring (specifically combined with Figure 6 The hollow arrow pointing to the center of the welded structure 300 indicates that the four corners 220 of the end cap 200 are all connected by the starting end 3101 and the ending end 3102 of the first weld 310. This can reduce the problem of insufficient molten pool 330 and other welding defects caused by the welding of two adjacent first welds 310 ending at the same corner 220 of the end cap 200. The end cap 200 and the shell 100 have good welding quality and good welded structural strength at the corner 220 of the end cap 200.

[0153] After the final welding is completed, the conveying mechanism 570 moves the second fixture, the housing 100 and the end cap 200 to the second trimming station 560 for trimming, thus completing the welding of the end cap 200 and the housing 100 of the battery cell 20.

[0154] Of course, in other embodiments, the moving directions of the four welding heads 400 are arranged to form a counterclockwise rotating ring, which can be set according to actual needs.

[0155] It should be noted here that, in combination Figure 6 and Figure 10As shown, the moving direction of the welding head 400 (the welding direction of the weld) can also be determined based on the shape of the weld. The weld is fish-scale shaped, consisting of several crescent-shaped structures stacked along the moving direction of the welding head 400. The opening direction of these crescent-shaped structures is the moving direction of the welding head 400. In other words, the welding direction of the weld can be determined based on the opening direction of the crescent-shaped structures on the weld. Therefore, the starting and ending points of the weld can be determined based on the welding direction. The welding head 400 can be a laser welding head, an electric welding head, etc., and the specific welding method can be selected according to actual needs; it is not limited here.

[0156] In another embodiment of this application, combined with Figure 13 , Figure 17 and Figure 18 As shown, at least one first weld 310 of the provided battery cell 20 includes a first weld segment 3111 and a second weld segment 3112, the first weld segment 3111 and the second weld segment 3112 are connected, and the first weld segment 3111 and the second weld segment 3112 are distributed along the length direction of the corresponding edge 210 of the end cap 200.

[0157] The first weld segment 3111 refers to a weld structure that extends along the length of the edge 210 of the end cap 200.

[0158] The second weld segment 3112 refers to another weld structure extending along the length of the edge 210 of the end cap 200. It should be noted that the welding direction of the first weld segment 3111 can be the same as or opposite to the welding direction of the second weld segment 3112.

[0159] The first weld segment 3111 and the second weld segment 3112 are connected. It can be understood that the first weld 310 formed by the first weld segment 3111 and the second weld segment 3112 is continuous and unbroken, so as to achieve a sealed connection between the housing 100 and the end cover 200.

[0160] At least one first weld 310, for example for a single battery cell 20, the first weld 310 at at least one edge 210 of the end cap 200 adopts a structure in which the first weld sub-segment 3111 and the second weld sub-segment 3112 are connected, which can specifically be two edges 210, three edges 210 or more edges 210.

[0161] In this embodiment of the application, the battery cell 20 has a first weld 310, which includes a first weld segment 3111 and a second weld segment 3112. In the actual manufacturing process, the first weld segment 3111 and the second weld segment 3112 can be welded in two steps to obtain the first weld 310, making the welding operation between the shell 100 and the end cap 200 simpler and more convenient.

[0162] In another embodiment of this application, combined with Figure 13 , Figure 17 and Figure 18 As shown, the first weld segment 3111 and the second weld segment 3112 of the provided battery cell 20 are stacked at their ends that are close to each other.

[0163] The first weld segment 3111 and the second weld segment 3112 are connected at their relatively close ends in a stacked manner. It can be understood that the weld at the connection between the first weld segment 3111 and the second weld segment 3112 is stacked, that is, the connection between the first weld segment 3111 and the second weld segment 3112 will be welded at least twice. This can increase the welding strength at the connection between the first weld segment 3111 and the second weld segment 3112, reduce welding defects, improve the welding quality between the end cover 200 and the housing 100, and improve the reliability of the battery cell 20.

[0164] In another embodiment of this application, combined with Figure 13 , Figure 17 and Figure 18 As shown, the length of the first weld segment 3111 of the provided battery cell 20 is greater than the stack length of two adjacent first welds 310, and the length of the second weld segment 3112 is greater than the stack length of two adjacent first welds 310. The stack length of two adjacent first welds 310 can refer to the length of a section of weld where two adjacent first welds 310 overlap, or it can refer to the weld length at the corner 220 of the end cover 200.

[0165] The length of the first weld segment 3111 is greater than the stack length of the two adjacent first welds 310. It can be understood that the first weld segment 3111 can completely cover the corner 220 of the end cap 200 and can extend from the corner 220 of the end cap 200. This can reduce the number of times the first weld segment 3111 and the second weld segment 3112 meet at the corner 220 of the end cap 200, thereby improving the welding strength and welding quality at the corner 220 of the end cap 200.

[0166] The length of the second weld segment 3112 is greater than the stack length of the two adjacent first welds 310. It can be understood that the second weld segment 3112 can completely cover the corner 220 of the end cap 200 and can extend from the corner 220 of the end cap 200. This can reduce the number of first weld segments 3111 and second weld segments 3112 connecting at the corner 220 of the end cap 200, and improve the welding strength and welding quality at the corner 220 of the end cap 200.

[0167] The battery cell 20 of this application embodiment can improve the welding strength and welding quality at the corner 220 of the end cover 200.

[0168] In another embodiment of this application, combined with Figure 13 , Figure 17 and Figure 18 As shown, the end of the first weld segment 3111 of the provided battery cell 20 is stacked with the end of the second weld segment 3112.

[0169] The end point of the first weld segment 3111 is stacked with the end point of the second weld segment 3112. It can be understood that the welding end position of the first weld segment 3111 and the welding end position of the second weld segment 3112 are both located at the connection between the first weld segment 3111 and the second weld segment 3112. In this way, the welding start position of the first weld segment 3111 and the welding start position of the second weld segment 3112 can be located at two adjacent corners 220 of the end cover 200, that is, the start end of the first weld segment 3111 and the start end of the second weld segment 3112 are located at the corner 220 of the end cover 200. This can reduce the welding defects such as insufficient molten pool 330 caused by the welding of two adjacent first welds 310 ending at the same corner 220 of the end cover 200. The end cover 200 and the shell 100 have good welding quality and good welded structural strength at the corner 220 of the end cover 200.

[0170] In another embodiment of this application, combined with Figure 13 , Figure 17 and Figure 18 As shown, the provided battery cell 20 has its end portions of the first weld segment 3111 and the second weld segment 3112 stacked together in the width direction of the first weld segment 3111.

[0171] In the width direction of the first weld segment 3111, the end portions of the first weld segment 3111 and the second weld segment 3112 that are relatively close to each other are stacked together. It can be understood that, combined with... Figure 19As shown, during the welding process, due to processing errors, the center lines of the welding head 400 at the edge 210 of the welding end cap 200 are not on the same horizontal plane. Consequently, the center lines B of the first weld segment 3111 and D of the second weld segment 3112 are not on the same horizontal plane, resulting in a vertical misalignment between the first weld segment 3111 and the second weld segment 3112. This causes the adjacent first weld segment 3111 and second weld segment 3112 to not completely overlap and cover each other, but rather partially overlap and cover each other. In addition, the partial overlap and coverage result in a larger welding area between the end cap 200 and the shell 100, leading to better welding reliability.

[0172] In one embodiment, combined with Figures 13-16 As shown, the end cap 200 is rectangular and includes two long sides and two short sides. The housing 100 is cuboid. When welding the end cap 200 and the housing 100 using welding equipment 500, the welding equipment 500 includes a conveying mechanism 570. The conveying mechanism 570 is provided with an assembly station 510, a first welding station 520, a first trimming station 530, a transfer station 540, a second welding station 550, and a second trimming station 560 in sequence along the conveying direction.

[0173] During welding, the end cap 200, electrode assembly 600 and housing 100 are first assembled at the assembly station 510, so that the end cap 200 covers the opening of the housing 100 and is fixed in the first fixture with the end cap 200 facing downward. The first fixture allows the long side of the end cap 200 to be exposed to facilitate welding of the long side.

[0174] Subsequently, the conveying mechanism 570 moves the first clamp, along with the housing 100 and end cap 200 fixed within it, to the first welding station 520. Then, two welding heads 400 weld the two long sides of the end cap 200 from opposite sides, with both welding heads 400 moving in the same direction from left to right (see details in conjunction with...). Figure 13 (The direction indicated by the hollow arrows on the front and rear sides) thus obtains the first weld 310 on the front side and the first weld 310 on the rear side. The left end of the first weld 310 on the front side and the left end of the first weld 310 on the rear side are both starting ends 3101, and the right end of the first weld 310 on the front side and the right end of the first weld 310 on the rear side are both ending ends 3102.

[0175] Afterwards, the conveying mechanism 570 continues to move the first clamp, end cap 200 and housing 100 to the first trimming station 530. After the first trimming station 530 trims the first weld 310 on the long side, the conveying mechanism 570 continues to move the first clamp, end cap 200 and housing 100 to the transfer station 540.

[0176] Then, at the transfer station 540, the end cap 200 and the housing 100 are moved into the second fixture, which allows the two short sides of the end cap 200 to be exposed, thus facilitating welding at the short sides.

[0177] Subsequently, the conveying mechanism 570 continues to move the second clamp, housing 100, and end cap 200 together to the second welding station 550. At the second welding station 550, two welding heads 400 weld the two short sides of the end cap 200 from opposite sides, and the two welding heads 400 move in the same direction (see details in conjunction with...). Figure 13 (In the direction indicated by the hollow arrows on the left and right sides near the end cap 200), both welding heads 400 move from back to front a certain distance and then stop welding. At this time, the short side of the end cap 200 is welded, thus obtaining the first weld segment 3111 on the left and the first weld segment 3111 on the right. Then, the two welding heads 400 continue to move forward. When they reach the front side of the end cap, the two welding heads 400 receive an instruction to start welding again, and at the same time, the two welding heads 400 move in opposite directions from front to back (see details in conjunction with...). Figure 13 (in the direction indicated by the hollow arrows on the left and right sides away from the end cap 200), thus obtaining the second weld segment 3112 on the left and the second weld segment 3112 on the rear, thereby completing the welding of the short side of the end cap 200. The starting end (i.e., the rear end) of the first weld segment 3111 on the left is connected to the starting end 3101 of the first weld 310 on the rear at the left rear corner 220 of the end cap 200. The ending end of the first weld segment 3111 on the left is connected to the ending end of the second weld segment 3112 on the left at the middle of the left side of the end cap 200. The starting end (i.e., the front end) of the second weld segment 3112 on the left is connected to the starting end 3101 of the first weld 310 on the front at the left front corner 220 of the end cap 200. The first weld segment 3112 on the right is connected to the first weld segment 3112 on the left at the left front corner 220 of the end cap 200. The starting end (i.e., the rear end) of 11 is connected to the ending end 3102 of the first weld 310 on the left side at the corner 220 on the right rear side of the end cap 200. The ending end of the first weld sub-segment 3111 on the right side is connected to the ending end of the second weld sub-segment 3112 on the right side at the middle of the right side of the end cap 200. The starting end (i.e., the front end) of the second weld sub-segment 3112 on the right side is connected to the ending end 3102 of the first weld 310 on the front side at the corner 220 on the right front side of the end cap 200. This reduces the overlap between the ending end 3102 of the first weld 310 on the front side and the ending end 3102 of the first weld 310 on the right side at the corner 220 on the right front side of the end cap 200, reduces the welding defects caused by the overlap of the ending end 3102, improves the welding quality, and increases the welding strength.

[0178] After the final welding is completed, the conveying mechanism 570 moves the second fixture, the housing 100 and the end cap 200 to the second trimming station 560 for trimming, thus completing the welding of the end cap 200 and the housing 100 of the battery cell 20.

[0179] During the welding process of the left and right sides of the end cap 200, the welding head 400 first welds part of the side 210 and then ends the welding prematurely. The welding head 400 continues to move forward. During the movement, preparation time is provided for the welding head 400 to move in the opposite direction, and time is also provided for the welding head 400 to receive the reverse movement welding operation command, thereby improving the welding efficiency of the end cap 200 and the housing 100.

[0180] In another embodiment of this application, combined with Figure 20 As shown, the welding structure 300 of the provided battery cell 20 also includes at least one second weld 320, which extends from the end point 3102 of the first weld 310 toward the beginning point 3101 of the first weld 310 and covers the first weld 310.

[0181] The second weld 320 refers to the weld structure covering the first weld 310. The weld structure 300 can be understood as a weld structure formed by another welding on the basis of the first weld 310, and this weld structure is the second weld 320.

[0182] The second weld 320 extends from the end point 3102 of the first weld 310 toward the beginning point 3101 of the first weld 310 and covers the first weld 310. It can be understood that the second weld 320 covers the end point 3102 of the first weld 310. In this way, another welding is performed at the end point 3102 of the first weld 310, which can improve the welding defects such as insufficient molten pool 330 at the end point 3102 of the first weld 310, thereby improving the welding quality and welding structure strength at the corner 220 of the end cap 200.

[0183] In another embodiment of this application, combined with Figure 20 As shown, the starting end of the second weld 320 of the provided battery cell 20 covers the ending end 3102 of the first weld 310.

[0184] The starting end of the second weld 320 refers to the section of weld formed at the beginning of the reverse back welding of the edge 210 of the end cap 200.

[0185] The starting end of the second weld 320 covers the ending end 3102 of the first weld 310. It can be understood that during welding, the welding head 400 can move along a predetermined direction to the corner 220 of the end cap 200 to form the first weld 310. Then, the welding head 400 moves in the opposite direction for a certain distance to weld and obtain the second weld 320. At this time, at the corner 220 of the end cap 200, the welding material at the starting end of the second weld 320 can accumulate to fill the molten pool 330 at the ending end 3102 of the first weld 310, thereby further improving the welding quality and welding structure strength at the corner 220 of the end cap 200.

[0186] In another embodiment of this application, combined with Figure 20 , Figure 21 and Figure 22 As shown, in the provided battery cell 20, in the width direction of the first weld 310, the second weld 320 partially covers the first weld 310.

[0187] In the width direction of the first weld 310, the second weld 320 partially covers the first weld 310. It is understood that during the welding process, due to processing errors, the center lines of the welding head 400 when welding the edge 210 of the end cap 200 are not on the same horizontal plane. As a result, the center lines of the first weld 310 and the second weld 320 are not on the same horizontal plane, which in turn causes the first weld 310 and the second weld 320 to be misaligned vertically. This results in the adjacent first weld 310 and second weld 320 not completely overlapping and covering each other, but partially overlapping and covering each other. In addition, the partial overlap and covering results in a larger welding area between the end cap 200 and the shell 100, and better welding reliability.

[0188] In another embodiment of this application, combined with Figure 20 , Figure 21 and Figure 22 As shown, at least one pair of opposing first welds 310 of the provided battery cell 20 are covered with second welds 320.

[0189] At least one pair of oppositely arranged first welds 310 are covered with second welds 320. It can be understood that when the two welding heads 400 are welding the opposite sides 210 of the end cap 200 respectively, after the two welding heads 400 weld in the same direction to obtain two oppositely arranged first welds 310, they move in opposite directions for a certain distance at the same time to obtain a pair of second welds 320. By controlling the two welding heads 400 to move synchronously in the same direction at the same time, the welding is easy to achieve and convenient for processing and manufacturing.

[0190] At least one pair of opposing first welds 310, it can be understood that in a single battery cell 20, one, two, three, or four or more pairs of opposing first welds 310 are covered by second welds 320, for example. Figure 13 As shown, a pair of oppositely arranged first welds 310 are covered by second welds 320. Their specific distribution can be determined according to the shape of the end cap 200 and the welding path, and is not limited here.

[0191] In another embodiment of this application, combined with Figure 20 As shown, in two adjacent first welds 310, the end point 3102 of one first weld 310 is stacked with the end point 3102 of the other first weld 310, and the end point 3101 of the second weld 320 is covered on the end point 3102 of at least one first weld 310.

[0192] In two adjacent first welds 310, the end point 3102 of one first weld 310 is stacked with the end point 3102 of the other first weld 310. It is understood that the two adjacent first welds 310 end at the same corner 220. This manufacturing may result in welding defects such as insufficient molten pool 330 at the corner 220. However, at least one end point 3102 of the first weld 310 is covered by the starting point 3101 of the second weld 320. In this way, back welding will be performed along the corresponding first weld 310 at the corner 220, thereby using the second weld 320 to fill the molten pool 330 at the corner 220, so as to overcome welding defects such as insufficient molten pool 330 and improve the strength and quality of the welded structure.

[0193] At least one end 3102 of the first weld 310 is covered by the beginning end of the second weld 320. It can be understood that the beginning end of the second weld 320 can be covered by the end ends 3102 of both first welds 310, or the beginning end of the second weld 320 can be covered by the end ends 3102 of one of the first welds 310. The specific choice can be made according to actual needs and is not limited here.

[0194] In another embodiment of this application, the length of the second weld 320 of the provided battery cell 20 is greater than the stack length of the two adjacent first welds 310.

[0195] In the battery cell 20 of this application embodiment, the length of the second weld 320 is greater than the stack length of the two adjacent first welds 310. In this way, the second weld 320 can completely cover the corner 220 of the end cover 200 and can be led out from the corner 200 of the end cover 200, thereby effectively improving the welding structure strength and welding quality at the corner 220 of the end cover 200.

[0196] In another embodiment of this application, the length of the first weld 310 of the provided battery cell 20 is greater than the length of the second weld 320.

[0197] In the battery cell 20 of this application embodiment, the length of the first weld 310 is greater than the length of the second weld 320, so that the second weld 320 covers a part of the first weld 310. The welding length is moderate, which is conducive to improving production efficiency and reducing welding costs.

[0198] In another embodiment of this application, combined with Figure 20 , Figure 21 and Figure 22 As shown, the first weld 310 of the provided battery cell 20 includes a first corner segment 3121, a first connecting segment 3122, a second connecting segment 3123, and a second corner segment 3124 connected in sequence. The first corner segment 3121 and the second corner segment 3124 are located at two adjacent corners 220 of the end cap 200, respectively. The second weld 320 covers the second connecting segment 3123 and the second corner segment 3124. The depth of the molten pool 330 of the welding structure 300 at the second corner segment 3124 is greater than the depth of the molten pool 330 of the welding structure 300 at the second connecting segment 3123, and the depth of the molten pool 330 of the welding structure 300 at the second connecting segment is greater than the depth of the molten pool 330 of the welding structure 300 at the first connecting segment 3122.

[0199] The first corner segment 3121 refers to a segment of the first weld 310 located at one of the two adjacent corners 220 of the end cap 200; for example Figure 20 As shown, the first corner segment 3121 refers to a section of the first weld 310 on the left side located at the left rear corner 220 of the end cap 200, or it refers to a section of the first weld 310 on the right side located at the right rear corner 220 of the end cap 200. The first corner segment 3121 is the starting end 3101 of the first weld 310.

[0200] The second corner segment 3124 refers to a segment of the first weld 310 located at one of the two adjacent corners 220 of the end cap 200, and this segment covers the second weld 320. For example Figure 20 , Figure 21 and Figure 22 As shown, the first corner segment 3121 refers to a section of the first weld 310 on the left side located at the front and rear corners 220 of the end cap 200, and the second corner segment 3124 is the end point 3102 of the first weld 310.

[0201] The second connecting segment 3123 refers to a section on the first weld 310 located between the first corner segment 3121 and the second corner segment 3124, which covers a portion of the second weld 320; for example Figure 20 , Figure 21 and Figure 22 As shown, the second connecting segment 3123 refers to a section of the first weld 310 on the left side located in the middle and covered by the second weld 320.

[0202] The first connecting segment 3122 refers to a section on the first weld 310 located between the first corner segment 3121 and the second corner segment 3124, which does not cover the portion of the second weld 320. For example Figure 20 , Figure 21 and Figure 22 As shown, the first connecting segment 3122 refers to a section of the first weld 310 on the left side that is located in the middle and does not cover the second weld 320.

[0203] The depth of the molten pool 330 at the second corner section 3124 of the welded structure 300 is greater than the depth of the molten pool 330 at the second connecting section 3123 of the welded structure 300, and the depth of the molten pool 330 at the second connection section of the welded structure 300 is greater than the depth of the molten pool 330 at the first connecting section 3122 of the welded structure 300. It can be understood that the deeper molten pool 330 at the second corner section 3124 of the welded structure 300 results in better welding reliability, thus making the welded structure at the corner 220 of the end cover 200 stronger. In addition, the deeper molten pool 330 at the second connection section of the welded structure 300 is greater than the depth of the molten pool 330 at the first connecting section 3122 of the welded structure 300, and the deeper molten pool 330 at the corner 220 near the end cover 200 of the welded structure 300 also results in better welding reliability, thus ensuring good welding strength at the corner 220 near the end cover 200, which is beneficial to improving the welding reliability between the end cover 200 and the shell 100. In addition, the welded structure 300 has one more first weld 310 at the second corner section 3124 than at the second connecting section 3123. With more welds, the molten pool 330 is deeper. Therefore, the molten pool 330 of the welded structure 300 at the second corner section 3124 is deeper than the molten pool 330 of the welded structure 300 at the second connecting section 3123. The welded structure 300 also has one more second weld 320 at the second connecting section 3123 than at the first connecting section 3122. With more welds, the molten pool 330 is deeper. Therefore, the molten pool 330 of the welded structure 300 at the second connecting section 3123 is deeper than the molten pool 330 of the welded structure 300 at the first connecting section 3122.

[0204] In another embodiment of this application, the lowest point E of the molten pool 330 of the second weld 320 of the provided battery cell 20 is located inside the end cap 200.

[0205] The lowest point of the molten pool 330 in the second weld 320 refers to the lowest point E of the molten pool 330 in its depth direction, for example... Figure 19 As shown, the depth direction of the molten pool 330 can be the X direction.

[0206] In this embodiment of the application, when the battery cell 20 is welded from the side of the end cover 200, the lowest point of the molten pool 330 of the second weld 320 is located inside the end cover 200. This prevents the housing 100 from being welded through during welding, thus preventing leakage. This results in good sealing performance between the housing 100 and the end cover 200 after welding, improving the reliability of the battery cell 20.

[0207] In one embodiment, combined with Figure 14 , Figure 15 , Figure 16 and Figure 20 As shown, the end cap 200 is rectangular and includes two long sides and two short sides. The housing 100 is cuboid. When welding the end cap 200 and the housing 100 using welding equipment 500, the welding equipment 500 includes a conveying mechanism 570. The conveying mechanism 570 is provided with an assembly station 510, a first welding station 520, a first trimming station 530, a transfer station 540, a second welding station 550, and a second trimming station 560 in sequence along the conveying direction.

[0208] During welding, the end cap 200, electrode assembly 600 and housing 100 are first assembled at the assembly station 510, so that the end cap 200 covers the opening of the housing 100 and is fixed in the first fixture with the end cap 200 facing downward. The first fixture allows the long side of the end cap 200 to be exposed to facilitate welding of the long side.

[0209] Subsequently, the conveying mechanism 570 moves the first clamp, along with the housing 100 and end cap 200 fixed within it, to the first welding station 520. Then, two welding heads 400 weld the two long sides of the end cap 200 from opposite sides, with both welding heads 400 moving in the same direction from left to right (see details in conjunction with...). Figure 20 (The direction indicated by the hollow arrows on the front and rear sides) and the long side of the end cap 200 is completely welded to obtain the first weld 310 on the front side and the first weld 310 on the rear side. The left end of the first weld 310 on the front side and the left end of the first weld 310 on the rear side are both starting ends 3101, and the right end of the first weld 310 on the front side and the right end of the first weld 310 on the rear side are both ending ends 3102.

[0210] Afterwards, the conveying mechanism 570 continues to move the first clamp, end cap 200 and housing 100 to the first trimming station 530. After the first trimming station 530 trims the first weld 310 on the long side, the conveying mechanism 570 continues to move the first clamp, end cap 200 and housing 100 to the transfer station 540.

[0211] Then, at the intermediate station 540, the end cap 200 and the housing 100 are moved into the second fixture so that the two short sides of the end cap 200 are exposed, thereby facilitating welding at the short sides.

[0212] Subsequently, the conveying mechanism 570 continues to move the second clamp, housing 100, and end cap 200 together to the second welding station 550. At the second welding station 550, two welding heads 400 weld the two short sides of the end cap 200 from opposite sides, with the two welding heads 400 moving in the same direction (see details in conjunction with...). Figure 20(In the direction indicated by the hollow arrows located on the left and right sides near the end cap 200), both welds move from back to front and completely weld the two short sides, thus obtaining a first weld 310 on the left side and a first weld 310 on the rear side. The rear ends of the first weld 310 on the left side and the first weld 310 on the rear side are both starting ends 3101, and the rear ends of the first weld 310 on the left side and the first weld 310 on the rear side are both ending ends 3102. At this time, the first weld 310 on the left side... The starting end 3102 (i.e., the first corner segment 3121) of the first weld 310 located on the rear side is connected to the starting end 3101 of the first weld 310 located on the rear side at the left rear corner 220 of the end cap 200. The ending end 3102 (i.e., the second corner segment 3124) of the first weld 310 located on the left side is connected to the starting end 3101 of the first weld 310 located on the front side at the left front corner 220 of the end cap 200. The starting end 3102 (i.e., the first corner segment 3121) of the first weld 310 located on the right side is connected to the first weld 310 located on the rear side. The end point 3102 of the first weld 310 is stacked at the right rear corner 220 of the end cap 200. The end point 3102 of the first weld 310 on the right side (i.e., the second corner segment 3124) is stacked with the end point 3102 of the first weld 310 on the front side at the right front corner 220 of the end cap 200. In order to improve the welding defects caused by the stacking of the end point 3102, the two weld heads 400 of the short side of the weld are moved in opposite directions from front to back, thereby forming two second welds 32 on the two short sides of the end cap 200. The starting end of the second weld 320 on the left side covers the ending end 3102 (i.e., the second corner segment 3124) of the first weld 310 on the left side and the second connecting segment 3123. At the same time, the starting end of the second weld 320 on the right side covers the ending end 3102 (i.e., the second corner segment 3124) of the first weld 310 on the right side and the second connecting segment 3123. This improves the welding defect at the right front corner 220 of the end cover 200, improves the welding quality, and increases the welding strength.

[0213] After the final welding is completed, the conveying mechanism 570 moves the second fixture, the housing 100, and the end cap 200 to the second trimming station 560 for trimming, thus completing the welding of the end cap 200 and the housing 100 of the battery cell 20. During this welding process, the two welding heads 400 move in the same direction, and the movement control of the welding heads 400 is simple and easy to implement.

[0214] In another embodiment of this application, combined with Figure 10 , Figure 17 and Figure 21 As shown, the welding structure 300 of the provided battery cell 20 is located on the side of the end cap 200.

[0215] The welding structure 300 is located on the side of the end cap 200. This means that the end cap 200 is welded to the housing 100 via side welding. The welding head 400 is welded to the front, rear, left, and right sides of the end cap 200. This welding method is simple, convenient, and easy to implement. Of course, in other embodiments, the end face and the housing 100 can also be top-welded, meaning the welding structure 300 is located on the top surface of the end cap 200.

[0216] In another embodiment of this application, combined with Figure 6 , Figure 13 and Figure 20 As shown, the end cap 200 of the provided battery cell 20 has an arc-shaped corner 220.

[0217] The corner 220 of the end cap 200 is arc-shaped. It can be understood that the corner 220 of the housing 100 and the end cap 200 are also arc-shaped. This makes the transition of the edge of the battery cell 20 smoother and improves the reliability of the battery cell 20. In addition, since the corner 220 of the end cap 200 is arc-shaped, during welding, when the welding head 400 moves in a straight line along one side 210 of the end cap 200, it can weld the corner 220. At the same time, when the welding head 400 moves in a straight line along the side 210 of the end cap 200 adjacent to the side 210, it can weld the corner 220 again. This allows the two adjacent first welds 310 to be stacked at the corner 220. In addition, the simple movement path of the welding head 400 also helps to improve welding efficiency.

[0218] In another embodiment, the corner 220 of the end cap 200 is in the shape of an arc, an elliptical arc, or the like.

[0219] In another embodiment of this application, combined with Figure 23 As shown, the end cap 200 of the provided battery cell 20 has a protrusion 230, which is inserted into the housing 100 through the opening.

[0220] The protrusion 230 refers to the protruding structure of the end cap 200 facing the inner surface of the housing 100. This protruding structure can be inserted into the housing 100. Through the limiting effect between the outer peripheral wall of the protrusion 230 and the inner wall of the housing 100, the end cap 200 can be stably fixed on the housing 100, improving the subsequent welding accuracy. In addition, in laser welding, the protrusion 230 can also block the laser emitted by the welding head 400, reducing the risk of laser leakage.

[0221] In another embodiment of this application, the distance L between the outer peripheral wall of the protrusion 230 of the battery cell 20 and the outer peripheral wall of the end cap 200 ranges from 0.1 mm to 0.5 mm.

[0222] In this embodiment of the application, the distance L between the outer peripheral wall of the protrusion 230 and the outer peripheral wall of the end cap 200 of the battery cell 20 is set within the aforementioned range, which allows the housing 100 and the end cap 200 to be stably and reliably welded together, resulting in good weld strength. If the distance L is set too small, the housing 100 will protrude too much beyond the end cap 200, leading to poor welding; if the distance L is set too large, the edge of the end cap 200 will protrude too much beyond the housing 100, also leading to poor welding. The distance L can be 0.1mm, 0.12mm, 0.14mm, 0.16mm, 0.18mm, 0.2mm, 0.22mm, 0.24mm, 0.26mm, 0.28mm, 0.3mm, 0.32mm, 0.34mm, 0.36mm, 0.38mm, 0.4mm, 0.42mm, 0.44mm, 0.46mm, 0.48mm, or 0.5mm.

[0223] In another embodiment of this application, a battery is provided, including the battery cell 20 described above.

[0224] The battery in this embodiment uses the aforementioned battery cell 20. The welded structure between the casing 100 and the end cap 200 in the battery cell 20 has good strength, resulting in good reliability of the battery cell 20 and better overall battery reliability and performance. Since the battery in this embodiment employs all the technical solutions of all the above embodiments, it also possesses all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here.

[0225] In another embodiment of this application, an electrical device is provided, including the battery described above.

[0226] The electrical device in this application embodiment uses the aforementioned battery, which has good reliability and performance, thus improving the performance and reliability of the electrical device. Since the electrical device in this application embodiment employs all the technical solutions of all the above embodiments, it also possesses all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here.

[0227] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, wherein, include: The shell has an opening; An end cap is welded to the opening and forms a welded structure. The welded structure includes a plurality of first welds, which are corresponding to the edges of the end cap. The plurality of first welds are connected to form a closed annular structure surrounding the end cap. Wherein, two adjacent first welds are stacked and connected at the corners corresponding to the end caps, the corners of the end caps are the welding start positions, and the molten pool depth of the welded structure at the corners of the end caps is greater than the molten pool depth of the welded structure at other parts.

2. The battery cell according to claim 1, wherein: In the width direction of the first weld, two adjacent first welds partially overlap at the corner of the end cap.

3. The battery cell according to any one of claims 1 to 2, wherein: In two adjacent first welds, the starting end of one first weld is stacked with the ending end of the other first weld.

4. The battery cell according to any one of claims 1 to 3, wherein: The lowest point of the molten pool of the first weld is located inside the end cap.

5. The battery cell according to any one of claims 1 to 4, wherein: At least one of the first welds includes a first weld segment and a second weld segment connected to each other, the first weld segment and the second weld segment being distributed along the length direction of the corresponding side of the end cap.

6. The battery cell according to claim 5, wherein: The first weld segment and the second weld segment are connected by overlapping at their relatively close ends.

7. The battery cell according to claim 6, wherein: The length of the first weld segment is greater than the stack length of two adjacent first welds, and the length of the second weld segment is greater than the stack length of two adjacent first welds.

8. The battery cell according to claim 7, wherein: The end point of the first weld segment is stacked with the end point of the second weld segment.

9. The battery cell according to any one of claims 6 to 8, wherein: In the width direction of the first weld segment, the end portions of the first weld segment and the second weld segment that are relatively close to each other are stacked and connected.

10. The battery cell according to any one of claims 1 to 2 or 4 to 7, wherein: The welded structure further includes at least one second weld, which extends from the end of the first weld toward the beginning of the first weld and covers the first weld.

11. The battery cell according to claim 10, wherein: The starting end of the second weld overlaps the ending end of the first weld.

12. The battery cell according to any one of claims 10-11, wherein: In the width direction of the first weld, the second weld portion covers the first weld.

13. The battery cell according to any one of claims 10 to 12, wherein: At least one pair of oppositely arranged first welds are covered by the second weld.

14. The battery cell according to any one of claims 10 to 13, wherein: In two adjacent first welds, the end of one first weld is stacked with the end of the other first weld, and the end of at least one first weld is covered by the beginning of the second weld.

15. The battery cell according to any one of claims 10 to 14, wherein: The length of the second weld is greater than the stack length of the two adjacent first welds.

16. The battery cell according to any one of claims 10 to 15, wherein: The length of the first weld is greater than the length of the second weld.

17. The battery cell according to any one of claims 10 to 16, wherein: The first weld includes a first corner segment, a first connecting segment, a second connecting segment, and a second corner segment connected in sequence. The first corner segment and the second corner segment are located at two adjacent corners of the end cap, and the second weld covers the second connecting segment and the second corner segment. Wherein, the molten pool depth of the welded structure at the second corner section is greater than the molten pool depth of the welded structure at the second connection section, and the molten pool depth of the welded structure at the second connection is greater than the molten pool depth of the welded structure at the first connection section.

18. The battery cell according to any one of claims 10 to 17, wherein: The lowest point of the molten pool of the second weld is located inside the end cap.

19. The battery cell according to any one of claims 1 to 18, wherein: The welded structure is located on the side of the end cap.

20. The battery cell according to any one of claims 1 to 19, wherein: The corner of the end cap is arc-shaped.

21. The battery cell according to any one of claims 1 to 20, wherein: The end cap has a protrusion that is inserted into the housing through the opening.

22. The battery cell according to claim 21, wherein: The distance between the outer peripheral wall of the protrusion and the outer peripheral wall of the end cap is in the range of 0.1mm to 0.5mm.

23. A battery, wherein: Includes the battery cell according to any one of claims 1 to 22.

24. An electrical appliance, wherein: Includes the battery as described in claim 23.

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