Battery cells, batteries and power consuming devices

Abstract

The present application discloses a battery cell 20, a battery 1100, and a power consumption device. The battery cell 20 includes a case 100 and an end cover 200. The case 100 has an opening. The end cover 200 is welded to the opening to form a welded structure 300. The welded structure 300 includes a plurality of first weld seams 310, which are located corresponding to edges 210 of the end cover 200. The plurality of first weld seams 310 are connected to form a closed ring structure around the periphery of the end cover 200, and two adjacent first weld seams 310 are stacked and connected at corresponding corners 220 of the end cover 200. The battery cell 20 has a high strength welded structure 300 at the corners 220 of the end cover 200. The strength of the welded structure 300 between the case 100 and the end cover 200 is also high, resulting in high welding quality and excellent structural reliability of the battery cell 20.

Description

[Technical Field]

[0001] This application relates to the field of welding technology, and more particularly to battery cells, batteries, and power consuming devices. [Background technology]

[0002] A battery cell includes components such as a case, an electrode assembly, and an end cover. The end cover is welded to the opening of the case, forming a sealed space with the case. The electrode assembly is located within this sealed space and performs electrochemical reactions, thereby enabling the battery to charge and discharge. However, the strength of the weld structure between the case and the end cover at the corners of the end cover is low. Summary of the Invention [Problem to be solved by the invention]

[0003] The purpose of the embodiments of the present application is to provide a battery cell, a battery, and a power consumption device that solves the problem of low strength of the welding structure between the case and the end cover at the corners of the end cover, but is not limited to this. [Means for solving the problem]

[0004] The technical solutions adopted in the embodiments of this application are as follows:

[0005] In a first aspect, a battery cell is provided, the battery cell including a case and an end cover, the case having an opening, the end cover being welded to the opening to form a welded structure, the welded structure including a plurality of first weld seams, the first weld seams being located corresponding to edges of the end cover, the plurality of first weld seams being connected to form a closed annular structure located around the outer periphery of the end cover, and two adjacent first weld seams being stacked and connected at corresponding corners of the end cover.

[0006] In the battery cell of the embodiment of the present application, two adjacent first weld seams are stacked at the corners of the end cover, so that the corners of the end cover are welded at least twice, forming at least two overlapping weld seams at the corners of the end cover. The overlapping of the two weld seams reduces welding defects at the corners of the end cover, thereby increasing the strength of the weld structure at the corners of the end cover, and the strength of the weld structure between the case and the end cover, resulting in high welding quality and excellent structural reliability of the battery cell.

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

[0008] In the battery cell of the embodiment of the present application, the first weld seam partially overlaps and covers the end cover, so the welded area between the end cover and the case is large and the welding reliability is excellent.

[0009] In one embodiment, in two adjacent first weld seams, the start end of one first weld seam and the end end of the other first weld seam are connected by overlapping.

[0010] In the battery cell of the embodiment of the present application, by using the corner portion of the end cover as the welding start position, the welding material formed by welding accumulates in the molten pool at the welding end position, thereby improving the welding quality at the welding end position and increasing the welding strength.

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

[0012] In the battery cell of the embodiment of the present application, the lowest point of the molten pool of the first weld seam is located inside the end cover, so there is no leakage due to the welding melting through the case, and the sealing performance between the case and the end cover after welding is excellent, improving the reliability of the battery cell in use.

[0013] In one embodiment, the depth of the molten pool of the welded structure at the corners of the end cover is greater than the depth of the molten pool of the welded structure at other locations.

[0014] In the battery cells of the examples of the present application, the welding quality is high, the strength of the welding structure between the case and the end cover is high, and the battery cells have excellent reliability in use.

[0015] In one embodiment, at least one first weld seam includes a first weld seam sub-segment and a second weld seam sub-segment connected to each other, and the first weld seam sub-segment and the second weld seam sub-segment are distributed along the longitudinal direction of corresponding sides of the end cover.

[0016] In the battery cell of the embodiment of the present application, the first weld seam sub-segment and the second weld seam sub-segment can be welded in two steps to obtain the first weld seam, making the welding operation of the case and the end cover easier and more convenient.

[0017] In one embodiment, the adjacent opposed ends of the first weld seam sub-segment and the second weld seam sub-segment are laminated together.

[0018] In the battery cell of the embodiment of the present application, the connection between the first weld seam sub-segment and the second weld seam sub-segment is welded at least twice, thereby increasing the welding strength of the connection between the first weld seam sub-segment and the second weld seam sub-segment, reducing welding defects, improving the welding quality between the end cover and the case, and improving the usage reliability of the battery cell.

[0019] In one embodiment, the length of the first weld seam sub-segment is longer than the stack length of two adjacent first weld seams, and the length of the second weld seam sub-segment is longer than the stack length of two adjacent first weld seams.

[0020] In the battery cell of the embodiment of the present application, the connection between the first weld seam sub-segment and the second weld seam sub-segment at the corner portion of the end cover can be reduced, thereby improving the welding strength and welding quality of the corner portion of the end cover.

[0021] In one embodiment, the end of the first weld seam sub-segment and the end of the second weld seam sub-segment are laminated together.

[0022] In the battery cell of the embodiment of the present application, problems of poor welding, such as insufficient molten pools, caused by two adjacent first weld seams ending at the same corner of the end cover can be alleviated, and both the end cover and the case have excellent welding quality at the corner of the end cover, resulting in a high strength weld structure.

[0023] In one embodiment, adjacent ends of the first weld seam sub-segment and the second weld seam sub-segment are partially overlappingly connected across the width of the first weld seam sub-segment.

[0024] In the battery cell of the embodiment of the present application, the first weld seam sub-segment and the second weld seam sub-segment partially overlap and cover each other, so the welded area between the end cover and the case is wide and the welding reliability is superior.

[0025] In one embodiment, the welded structure further includes at least one second weld seam, the second weld seam extending from the end of the first weld seam toward the beginning of the first weld seam and being covered by the first weld seam.

[0026] In the battery cell according to the embodiment of the present application, the welding quality of the corner portions of the end cover and the strength of the welded structure can be improved.

[0027] In one embodiment, the beginning of the second weld seam is covered by the ending of the first weld seam.

[0028] In the battery cell of the embodiment of the present application, the welding material at the starting end of the second weld seam is deposited to fill the molten pool at the ending end of the first weld seam, thereby further improving the welding quality of the corner portion of the end cover and the strength of the welded structure.

[0029] In one embodiment, the second weld seam is partially covered by the first weld seam in the width direction of the first weld seam.

[0030] In the battery cell of the embodiment of the present application, the second weld seam and the first weld seam partially overlap and cover each other, so the welded area between the end cover and the case is wide, and the welding reliability is superior.

[0031] In one embodiment, the second weld seam is covered by at least one pair of oppositely disposed first weld seams.

[0032] In the battery cell of the embodiment of the present application, two welding heads are used to weld two opposing sides of the end cover, respectively, and the two welding heads are welded in the same direction to obtain two opposing first weld seams, and then simultaneously moved a certain distance in opposite directions to obtain a pair of second weld seams. In this way, the two welding heads are simultaneously controlled to move back and forth in the same direction in sync, making the welding easy to achieve and convenient to process and manufacture.

[0033] In one embodiment, in two adjacent first weld seams, the end portion of one first weld seam is stacked with the end portion of the other first weld seam, and the end portion of at least one first weld seam covers the start end of the second weld seam.

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

[0035] In one embodiment, the length of the second weld seam is longer than the overlap length of two adjacent first weld seams.

[0036] In the battery cell according to the embodiment of the present application, the strength and welding quality of the welding structure of the corner portions of the end cover can be effectively improved.

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

[0038] In the battery cells of the examples of the present application, the welding length is appropriate, which is advantageous for improving production efficiency and reducing welding costs.

[0039] In one embodiment, the first weld seam includes a first corner segment, a first connection segment, a second connection segment, and a second corner segment connected in sequence, the first corner segment and the second corner segment being respectively located at two adjacent corner portions of the end cover, and the second weld seam is covered by the second connection segment and the second corner segment, wherein the depth of the molten pool of the welded structure at the second corner segment is deeper than the depth of the molten pool of the welded structure at the second connection segment, and the depth of the molten pool of the welded structure at the second connection segment is deeper than the depth of the molten pool of the welded structure at the first connection segment.

[0040] In the battery cells of the examples of the present application, the molten pool is deep and the welding reliability is excellent, so the welding strength near the corners of the end cover is also high, which is advantageous for improving the welding reliability between the end cover and the case.

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

[0042] In the battery cells of the embodiments of the present application, leakage due to melting through the case during welding does not occur, and the sealing performance between the case and the end cover after welding is excellent, improving the reliability of the battery cells in use.

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

[0044] In the battery cell of the embodiment of the present application, the welding method is simple, convenient, and easy to achieve.

[0045] In one embodiment, the corners of the end cover are arcuate.

[0046] In the battery cell according to the embodiment of the present application, the transition of the edges of the battery cell can be made smoother, which improves the reliability of the battery cell in use and makes welding easier.

[0047] In one embodiment, a protrusion is formed on the end cover, and the protrusion is inserted into the case through the opening.

[0048] In the battery cell of the embodiment of the present application, the end cover can be stably fixed to the case, improving the accuracy of subsequent welding.

[0049] In one embodiment, the range of the distance between the outer peripheral wall of the protrusion and the outer peripheral wall of the end cover is 0.1 mm to 0.5 mm.

[0050] In the battery cells of the examples of the present application, the case and end cover can be welded stably and reliably, and the strength of the welded structure is high.

[0051] In a second aspect, a battery is provided, the battery including the battery cell described above.

[0052] The battery of the embodiment of the present application employs the above battery cell, and the strength of the welding structure between the case and the end cover of the battery cell is high, the usage reliability of the battery cell is excellent, and the usage reliability and performance of the battery are also excellent.

[0053] In a third aspect, there is provided a power consuming device, said power consuming device comprising the battery described above.

[0054] The power consumption device of the embodiment of the present application employs the above battery, which has excellent reliability and performance in use, and is also advantageous in improving the performance and reliability of the power consumption device. [Brief explanation of the drawings]

[0055] In order to more clearly explain the technical solutions in the embodiments of the present application, the following briefly describes the drawings necessary for describing the embodiments or exemplary technologies. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without any creative efforts.

[0056] [Figure 1] 1 is a structural schematic diagram of a vehicle according to an embodiment of the present application; [Figure 2] 1 is a structural schematic diagram of a battery according to an embodiment of the present application; [Figure 3] 1 is a structural schematic diagram from one perspective of a battery cell according to an embodiment of the present application; [Figure 4] 1 is a schematic exploded structural view of a battery cell according to an embodiment of the present application; [Figure 5] FIG. 2 is a structural schematic diagram of a battery cell according to an embodiment of the present application from another perspective. [Figure 6] 1 is a structural schematic diagram of a welding structure of a battery cell according to an embodiment of the present application; [Figure 7] 7 is a structural schematic diagram of a welding device for producing the welded structure shown in FIG. 6. [Figure 8] 8 is a flowchart of welding at a first welding station using the welding machine shown in FIG. 7. [Figure 9] 8 is a flowchart of welding at a second welding station using the welding machine shown in FIG. 7. [Figure 10] 8 is a schematic diagram of welding at a first welding station by the welding equipment shown in FIG. 7. FIG. [Figure 11] 1 is a partial cross-sectional view of a battery cell according to one embodiment of the present application. [Figure 12] 1 is a partial cross-sectional view of a first weld seam of a welded structure of a battery cell according to an embodiment of the present application. [Figure 13] 1 is a structural schematic diagram of a welding structure of a battery cell according to an embodiment of the present application; [Figure 14] 1 is a structural schematic diagram of a welding equipment for a battery cell welding structure according to an embodiment of the present application; [Figure 15] 15 is a flowchart of welding at a first welding station using the welding machine shown in FIG. 14. [Figure 16] 15 is a flowchart of welding at a second welding station using the welding machine shown in FIG. 14. [Figure 17] 14 is a schematic diagram of welding at a second welding station by the welding equipment to produce the welded structure shown in FIG. 13. [Figure 18] FIG. 18 is a partial enlarged view of a portion A in FIG. [Figure 19] 1 is a partial cross-sectional view of a welding structure of a battery cell according to an embodiment of the present application, at a position where a first weld seam sub-segment and a second weld seam sub-segment are stacked. FIG. [Figure 20] 1 is a structural schematic diagram of a welding structure of a battery cell according to an embodiment of the present application; [Figure 21] 21 is a schematic diagram of welding at a second welding station by welding equipment to produce the welded structure shown in FIG. 20. [Figure 22] FIG. 18 is a partial enlarged view of a portion F in FIG. [Figure 23] 1 is a partial cross-sectional view of a battery cell according to one embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0057] The following describes in detail the embodiments of the present application, and examples of the embodiments are shown in the drawings, where the same or similar reference numerals throughout the specification represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are merely illustrative and are for the purpose of interpreting the present application, and should not be understood as limiting the present application.

[0058] In the description of this application, it should be understood that orientations or positional relationships indicated by terms such as "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" are orientations or positional relationships indicated based on the drawings, and are intended merely to facilitate and simplify the description of this application, and do not indicate or imply that the devices or elements shown necessarily have a specific orientation or are constructed and operated in a specific orientation, and therefore cannot be understood as limiting this application.

[0059] Additionally, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or the number of the indicated technical features. Therefore, a feature qualified by "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of this application, unless expressly limited otherwise, "plurality" means two or more.

[0060] In this application, unless otherwise clearly defined and limited, the terms "attached," "connected," "coupled," "fixed," etc. should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, or an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, an internal communication between two elements, or an interactive relationship between two elements. Those skilled in the art can understand the specific meanings of the above terms in this application according to specific circumstances.

[0061] In the description of this application, it should be explained that the term "and / or" is merely for describing the relation between related objects, and indicates that three kinds of relations may exist, for example, A and / or B can indicate three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0062] It should also be noted that in the examples of the present application, the same components or parts are represented by the same symbols, and for identical parts or components in the embodiments of the present application, it is possible to assign a drawing reference symbol to only one of the parts or components as an example in the figures, and it should be understood that for other identical parts, the drawing reference symbol is also applicable.

[0063] In this application, terms such as "one embodiment," "some embodiments," "example," "particular example," or "some examples" mean that a specific feature, structure, material, or characteristic described with reference to this embodiment or example is included in at least one embodiment or example of this application. In this specification, exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, unless mutually inconsistent, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described herein.

[0064] In this specification, for ease of explanation, the Z axis in the 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 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, and the X axis in the drawings represents the front-to-back direction, with the positive direction of the X axis representing rear and the negative direction of the X axis representing front.

[0065] From the viewpoint of the development of the market situation, batteries are being applied more and more widely. Batteries are not only applied to energy storage power systems such as hydroelectric power plants, thermal power plants, wind power plants and solar power plants, but also widely applied to electric transportation such as electric bicycles, electric motorcycles and electric cars, as well as military equipment and aerospace, etc. As the application fields of power batteries continue to expand, the market demand for them also continues to increase.

[0066] A battery cell includes components such as a case, an electrode assembly, and an end cover. The end cover is welded to an opening of the case, forming a sealed space with the case. The electrode assembly is located within this sealed space and performs electrochemical reactions, thereby enabling the battery to charge and discharge. However, the strength of the welded structure between the case and the end cover is low.

[0067] The applicant discovered that one of the main reasons for the low strength of the welded structure between the case and the end cover is that poor welding is likely to occur at the corners of the end cover during the welding process between the case and the end cover, resulting in problems such as welding defects in the weld between the case and the end cover, and as a result, the strength of the welded structure between the case and the end cover is low. Even after increasing the welding power and deepening the molten pool, problems still exist in the strength of the welded structure between the case and the end cover. Further research has revealed that poor welding is likely to occur at the corners of the end cover.

[0068] Therefore, in order to improve the welding strength between the case and the end cover, the applicant has designed a battery cell after thorough research, in which at least two welding seams are stacked at the corners of the end cover between the end cover and the case of this battery cell, thereby increasing the welding strength at the corners and improving the welding quality of the battery cell, which is advantageous for increasing the structural strength of the battery and improving the reliability of the battery.

[0069] In the battery cells, batteries, and power consumption devices using batteries as power sources disclosed in the embodiments of the present application, the power consumption devices may be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric motorcycles, electric cars, boats, spacecraft, etc. Here, the electric toys may include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys, and the spacecraft may include airplanes, rockets, space shuttles, and spaceships.

[0070] In the following embodiment, for ease of explanation, an example will be described in which the power consumption device of one embodiment of the present application is a vehicle 1000.

[0071] Referring to FIG. 1, FIG. 1 is a structural schematic diagram of a vehicle 1000 according to some embodiments of the present application. The vehicle 1000 may be a fuel oil vehicle, a natural gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, an extended range vehicle, etc. A battery 1100 is installed inside the vehicle 1000, and the battery 1100 may be installed at the bottom, front, or rear of the vehicle 1000. The battery 1100 may be used to power the vehicle 1000, for example, the battery 1100 may function as an operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 1200 and a motor 1300, and the controller 1200 is used to control the battery 1100 to power the motor 1300, for example, for operating power consumption needs during startup, navigation, and driving of the vehicle 1000.

[0072] In some embodiments of the present application, the battery 1100 can not only function as an operating power source for the vehicle 1000, but can also provide driving power to the vehicle 1000 by replacing or partially replacing fuel oil or natural gas as the driving power source for the vehicle 1000.

[0073] 2 , as one embodiment of a battery 1100, the battery 1100 includes a housing 10 and battery cells 20, and the battery cells 20 are housed within the battery housing 10. Here, the battery housing 10 is used to provide a housing space for the battery cells 20, and the battery housing 10 can adopt various structures. In some embodiments, the battery housing 10 may include a first portion 11 and a second portion 12, and the first portion 11 and the second portion 12 are placed over each other, and the first portion 11 and the second portion 12 jointly define a housing space for housing the battery cells 20. The second part 12 may have a hollow structure with one end open, and the first part 11 may have a plate-like structure, with the first part 11 covering the open side of the second part 12, so that the first part 11 and the second part 12 jointly define an accommodating space, or both the first part 11 and the second part 12 may have a hollow structure with one end open, with the open side of the first part 11 covering the open side of the second part 12. Of course, the battery housing 10 formed by the first part 11 and the second part 12 may have various shapes, such as a cylinder or a rectangular parallelepiped.

[0074] In the battery 1100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in series-parallel connection, where series-parallel connection means that the multiple battery cells 20 are connected in either series or parallel.

[0075] In one embodiment, a plurality of battery cells 20 may be directly connected in series, in parallel, or in series-parallel, and then the entire battery cell set 20 may be housed in the housing 10. Of course, the battery 1100 may first be formed by connecting a plurality of battery cells 20 in series, in parallel, or in series-parallel to form a battery module, and then the entire battery module may be connected in series, in parallel, or in series-parallel to form the entire battery module, which is housed in the housing 10. The battery 1100 may further include other structures; for example, the battery 1100 may further include bus members for realizing electrical connection between the plurality of battery cells 20.

[0076] Here, each battery cell 20 may be a secondary battery or a primary battery, and may be, but is not limited to, a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery. The battery cells 20 may be flat, rectangular, or have other shapes.

[0077] As another embodiment of the battery 1100, the battery 1100 may not include the housing 10, but may be assembled into a power consuming device after electrically connecting multiple battery cells 20 and forming an entire body with the necessary fixing structure.

[0078] 3 and 4, Fig. 3 is a structural schematic diagram of a battery cell 20 according to some embodiments of the present application, and Fig. 4 is an exploded structural schematic diagram of the battery cell 20 according to some embodiments of the present application. The battery cell 20 refers to the smallest unit that constitutes a battery. As shown in Fig. 3, the battery cell 20 includes an end cover 200, a case 100, an electrode assembly 600, and other functional components.

[0079] The end cover 200 is a component that covers the opening of the case 100 and isolates the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cover 200 may be adapted to fit the case 100. Alternatively, the end cover 200 may be made of a material (e.g., aluminum alloy) with a certain hardness and strength. This makes the end cover 200 less likely to deform when subjected to extrusion or impact, thereby enabling the battery cell 20 to have higher structural strength and improved safety performance. The end cover 200 may be provided with functional components such as electrode terminals 241. The electrode terminals 241 may be used for electrical connection with the electrode assembly 600 to input or output electrical energy to or from the battery cell 20. In some embodiments, the end cover 200 may also be provided with a pressure release mechanism 242 for releasing internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. The end cover 200 may be made of various materials such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., but is not particularly limited thereto in the embodiments of the present application. In some embodiments, an insulating member may also be installed inside the end cover 200, and the insulating member may be used to isolate the electrical connection members inside the case 100 from the end cover 200 and reduce the risk of short circuits. For example, the insulating member may be made of plastic, rubber, etc.

[0080] The case 100 is an assembly that is combined with the end cover 200 to form an internal environment for the battery cell 20. The formed internal environment may be used to accommodate the electrode assembly 600, electrolyte, and other components. The case 100 and the end cover 200 may be separate components, or an opening may be provided in the case 100. The end cover 200 is placed over the opening to form the internal environment for the battery cell 20. The end cover 200 and the case 100 may be integrated, but are not limited to this. Specifically, the end cover 200 and the case 100 may form a common connection surface before other components are inserted into the case. When the interior of the case 100 needs to be packaged, the end cover 200 is placed over the case 100. The case 100 may have various shapes and sizes, such as a rectangular parallelepiped, a cylindrical body, or a hexagonal prism. Specifically, the shape of the case 100 may be determined by the specific shape and size of the electrode assembly 600. The case 100 may be made of various materials such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application is not particularly limited thereto.

[0081] The electrode assembly 600 is a component where an electrochemical reaction occurs in the battery cell 20. One or more electrode assemblies 600 may be included in the case 100. The electrode assembly 600 includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell 20, active ions (e.g., lithium ions) travel back and forth between the positive electrode and the negative electrode, intercalating and deintercalating. The separator, which is installed between the positive electrode and the negative electrode, serves to reduce short circuits between the positive electrode and the negative electrode and allows the active ions to pass through.

[0082] 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.

[0083] 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.

[0084] In some embodiments, the separator is a separator. The present application does not particularly limit the type of separator, and any well-known porous structure separator with good chemical stability and mechanical stability can be selected.

[0085] In some embodiments, the electrode assembly 600 is a wound structure, in which the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0086] In some embodiments, the electrode assembly 600 is a laminated structure.

[0087] As shown in FIGS. 5 and 6 , in one embodiment of the present application, a battery cell 20 is provided, the battery cell 20 including a case 100 and an end cover 200, the case 100 having an opening, the end cover 200 being welded to the opening to form a welded structure 300, the welded structure 300 including a plurality of first weld seams 310, the first weld seams 310 being located corresponding to the sides 210 of the end cover 200, the plurality of first weld seams 310 being connected to form a closed ring structure located on the outer periphery of the end cover 200, and two adjacent first weld seams 310 being stacked and connected at corresponding corners 220 of the end cover 200.

[0088] The end cover 200 refers to a member that covers the opening of the case 100, for example, the member that covers the opening of the case 100 to isolate the internal environment of the battery cell 20 from the external environment. Here, the shape of the end cover 200 also matches the shape of the opening of the case 100, and the shape of the end cover 200 may be a polygon such as a triangle, a square, or a pentagon. For example, as shown in FIG. 5, the shape of the end cover 200 is rectangular.

[0089] The case 100 refers to the above-mentioned assembly that forms the internal environment of the battery cell 20 in combination with an outer protective member for the battery cell 20, for example, an end cover 200.

[0090] The end cover 200 is welded to the opening to form a welded structure 300, and as can be understood, the edge 210 of the end cover 200 is welded to the edge corresponding to the opening of the case 100, thereby connecting the case 100 and the end cover 200 as a whole, where the welded structure 300 refers to the connecting member formed after welding the edge 210 of the end cover 200 to the edge corresponding to the opening of the case 100.

[0091] The welded structure 300 includes a plurality of first weld seams 310, which are located corresponding to the sides 210 of the end cover 200. As can be understood, the first weld seams 310 refer to the weld seams formed after welding the sides 210 of the end cover 200 to the sides 210 corresponding to the openings of the case 100. The number of first weld seams 310 is the same as the number of sides 210 of the end cover 200. For example, as shown in Figures 6 and 13, the end cover 200 is rectangular, and first weld seams 310 are located corresponding to the four sides 210 of the end cover 200, i.e., the number of first weld seams 310 is four. The welding structures 300 at the four sides 210 of the end cover 200 correspond to the first welding seams 310 located on the front, rear, left and right sides in the drawings, respectively. The welding structures 300 at the four corners 220 of the end cover 200 can refer to the inclined welding structures at the four corners in FIGS. 6 and 13. The specific correspondence can be one-to-one with reference to the directions indicated by the solid arrows in the drawings. It should be noted here that for ease of illustration, the welding structures 300 in FIGS. 6 and 13 are divided into six segments, and In this figure, the starting end 3101 and the ending end 3102 of the first weld seam 310 are separated from the first weld seam 310 and are respectively located within the two inclined welded structures. However, in the actual product, the six segments of the welded structures 300 in the figure are connected sequentially from end to end, that is, the starting end 3101 and the ending end 3102 of the first weld seam 310 are connected to the first weld seam 310, and the welded structure 300 is an annular welded structure installed on the outer periphery of the end cover 200, formed by stacking and connecting four first weld seams 310 from end to end.

[0092] Of course, in another embodiment, the end cover 200 is triangular, and the three sides 210 of the end cover 200 are respectively provided with corresponding first welding seams 310, that is, the number of first welding seams 310 is three; of course, in other embodiments, the end cover 200 may be pentagonal, hexagonal, etc.

[0093] The plurality of first weld seams 310 are connected to form a closed annular structure and are disposed around the periphery of the end cover 200, and as can be seen, the plurality of first weld seams 310 are connected end to end to form a closed annular structure and are disposed around the periphery of the end cover 200, thereby achieving an overall sealed connection between the end cover 200 and the case 100.

[0094] The corner portion 220 of the end cover 200 refers to the connection portion of two adjacent side portions 210 of the end cover 200 (see FIG. 6).

[0095] Two adjacent first weld seams 310 are laminated and connected at corresponding corner portions 220 of the end cover 200. As can be seen, at the connection between two adjacent first weld seams 310, one first weld seam 310 is covered by the other first weld seam 310 to form a welded laminate structure, and this welded laminate structure is located at the corner portion 220 of the end cover 200. In the case of welding, when welding one side portion 210 connected to this corner portion 220, welding is performed up to this corner portion 220 to form a weld seam of one layer in the weld seam laminate structure, and when welding the other side portion 210 connected to this corner portion 220, welding is performed up to this corner portion 220 to form a weld seam of another layer in the weld seam laminate structure. In other words, the corner portion 220 of the end cover 200 is welded at least twice, and at least two weld seams are formed. It should be noted here that every two adjacent first weld seams 310 may be stacked and connected at the corner portion 220 corresponding to the end cover 200, or some of the two adjacent first weld seams 310 may be stacked and connected at the corner portion 220 corresponding to the end cover 200.

[0096] In the battery cell 20 of the embodiment of the present application, two adjacent first weld seams 310 are stacked at the corner portion 220 of the end cover 200, so that the corner portion 220 of the end cover 200 is welded at least twice, forming at least two overlapping weld seams at the corner portion 220 of the end cover 200. The overlapping of the two weld seams reduces welding defects at the corner portion 220 of the end cover 200, thereby increasing the strength of the weld structure at the corner portion 220 of the end cover 200, and the strength of the weld structure between the case 100 and the end cover 200, resulting in high welding quality and excellent structural reliability of the battery cell 20.

[0097] In another embodiment of the present application, in the battery cell 20 provided, two adjacent first weld seams 310 in the width direction of the first weld seams 310 partially overlap at the corner portions 220 of the end cover 200 .

[0098] For example, as shown in FIG. 10, the width direction of the first weld seam 310 is the Z direction.

[0099] In the width direction of the first weld seams 310, two adjacent first weld seams 310 partially overlap at the corner portions 220 of the end cover 200. As can be seen, due to processing errors during the welding process, the center lines B of the welding head 400 when welding the two adjacent side portions 210 of the end cover 200 are not located on the same horizontal plane, and the center lines of the two adjacent first weld seams 310 formed as a result are also not located on the same horizontal plane. As a result, the two adjacent first weld seams 310 are shifted up and down. As a result, the two adjacent first weld seams 310 do not completely overlap and cover, but partially overlap and cover again. This results in a wider weld area between the end cover 200 and the case 100 and better welding reliability.

[0100] In another embodiment of the present application, as shown in FIG. 6, in the battery cell 20 provided, in two adjacent first weld seams 310, the starting end 3101 of one first weld seam 310 and the ending end 3102 of the other first weld seam 310 are stacked and connected.

[0101] The starting end 3101 of the first weld seam 310 refers to the weld seam segment formed when welding of the side portion 210 of the end cover 200 begins.

[0102] The end portion 3102 of the first weld seam 310 refers to the weld seam segment formed when the welding of the side portion 210 of the end cover 200 is nearly completed.

[0103] 6 and 13, in two adjacent first weld seams 310, the start end 3101 of one first weld seam 310 and the end end 3102 of the other first weld seam 310 are overlappingly connected, and as can be seen, in the corner portion 220 of the end cover 200, the start end 3101 of one first weld seam 310 and the end end 3102 of the other first weld seam 310 are overlappingly connected, that is, the corner portion 220 of the end cover 200 is the welding start position of one first weld seam 310, and , the weld termination position of the other first weld seam 310, and thus it is possible to reduce welding defects such as an insufficient weld pool 330 caused by welding of two adjacent first weld seams 310 ending at the same corner 220 of the end cover 200. Furthermore, by using the corner 220 of the end cover 200 as the welding start position, the weld material formed by welding is deposited in the weld pool 330 at the welding end position, thereby improving the weld quality and weld strength at the welding end position. It should be noted here that the start end 3101 and the end end 3102 of all two adjacent first weld seams 310 may be overlap-connected at the corner 220 corresponding to the end cover 200, or some two adjacent first weld seams 310 may be overlap-connected at the corner 220 corresponding to the end cover 200.

[0104] In another embodiment of the present application, as shown in FIG. 12 , in the battery cell 20 provided, the lowest point C of the molten pool 330 of the first weld seam 310 is located inside the end cover 200 .

[0105] The molten pool 330 refers to a liquid metal portion having a certain geometric shape formed in the case 100 and the end cover 200 by the action of the welding heat source, and here, the molten pool 330 may also be a portion formed after the liquid metal portion has hardened.

[0106] The lowest point of the molten pool 330 of the first weld seam 310 refers to the lowest point C in the depth direction of the molten pool 330, and for example, as shown in Figure 12, the depth direction of the molten pool 330 may be the X direction.

[0107] In the battery cell 20 of the embodiment of the present application, when welding is performed from the side of the end cover 200, the lowest point of the molten pool 330 of the first weld seam 310 is located inside the end cover 200. This prevents leakage due to welding through the case 100, provides excellent sealing performance after welding between the case 100 and the end cover 200, and improves the reliability of use of the battery cell 20.

[0108] In another embodiment of the present application, the depth of the molten pool 330 of the welded structure 300 of the battery cell 20 provided at the corner portion 220 of the end cover 200 is deeper than the depth of the molten pool 330 of the welded structure 300 at other portions.

[0109] In the battery cell 20 of the embodiment of the present application, the depth of the molten pool 330 at the corner portion 220 of the end cover 200 is deeper than the depth of the molten pool 330 at other locations, so the welding structure 300 at the corner portion 220 of the end cover 200 is highly reliable and has high welding quality, and the strength of the welding structure between the case 100 and the end cover 200 is high, resulting in excellent usage reliability of the battery cell 20.

[0110] In one embodiment, as shown in FIGS. 6 to 9, the end cover 200 is rectangular, has two long sides and two short sides, and the case 100 is a rectangular parallelepiped. When the end cover 200 and the case 100 are welded using the welding equipment 500, the welding equipment 500 includes a conveying mechanism 570, and the conveying mechanism 570 has 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 sequentially arranged along the conveying direction (see FIG. 7).

[0111] In the case of welding, first, the end cover 200, the electrode assembly 600 and the case 100 are assembled at the assembly station 510, whereby the end cover 200 is placed over the opening of the case 100 and fixed to the first clamp, and the end cover 200 is placed facing downward, and the first clamp exposes the long side of the end cover 200 to facilitate welding of the long side, and then the transport mechanism 570 moves the first clamp, the case 100 fixed to the first clamp and the end cover 200 to the first welding station 520.

[0112] Then, the two welding heads 400 respectively weld the two long sides from opposite sides of the end cover 200, and the moving directions of the two welding heads 400 are opposite, where the welding head 400 located on the rear side moves from left to right, thereby obtaining a first welding seam 310 located on the rear side, which has a starting end 3101 at its left end and a terminal end 3102 at its right end, and the welding head 400 located on the front side moves from right to left, thereby obtaining a first welding seam 310 located on the front side, which has a terminal end 3102 at its left end and a starting end 3101 at its right end.

[0113] Thereafter, the conveying mechanism 570 continues to drive the first clamp and end cover 200 and the case 100, moving them to the first trimming station 530, and after trimming the first weld seam 310 on the long side at the first trimming station 530, the conveying mechanism 570 continues to drive the first clamp and end cover 200 and the case 100, moving them into the transfer station 540.

[0114] Thereafter, at transfer station 540, end cover 200 and case 100 are moved to a second clamp, thereby exposing the two short sides of end cover 200, thereby facilitating welding of the short sides.

[0115] Then, the transport mechanism 570 continues to drive the second clamp, the case 100, and the end cover 200 to move them to the second welding station 550. At the second welding station 550, the two welding heads 400 respectively weld the two short sides of the end cover 200 from opposite sides. The two welding heads 400 move in opposite directions, and the welding head 400 located on the left side moves from rear to front, thereby forming the first weld 310 located on the left side. The first weld seam 310 has a front end as a starting end 3101 and a rear end as a terminal end 3102. The end portion 3102 of the first weld seam 310 located on the rear side and the start portion 3101 of the first weld seam 310 located on the rear side are overlapped and connected at the left rear corner 220 of the end cover 200, and the start portion 3101 of the first weld seam 310 located on the left side and the end portion 3102 of the first weld seam 310 located on the front side are overlapped and connected at the left front corner 220 of the end cover 200, and the welding head 400 located on the right side moves from rear to front, thereby obtaining the first weld seam 310 located on the right side, which has the end portion 3102 at its front end and the start portion 3101 of the first weld seam 310 located on the front side. The start end 3101 of the first weld seam 310 located on the right side and the end end 3102 of the first weld seam 310 located on the rear side are overlapped and connected at the right rear corner 220 of the end cover 200, and the end end 3102 of the first weld seam 310 located on the right side and the start end 3101 of the first weld seam 310 located on the front side are overlapped and connected at the right front corner 220 of the end cover 200. In this way, the movement direction of the four welding heads 400 forms a ring that rotates clockwise by enclosing it (specifically, the welding structure 3 in FIG. 6 00) and at the four corners, i.e., the four corner portions 220, of the end cover 200, the starting end 3101 and the ending end 3102 of the first weld seam 310 are connected in layers, thus reducing the problem of poor welding such as insufficient molten pool 330 caused by the welding of two adjacent first weld seams 310 ending at the same corner portion 220 of the end cover 200, and both the end cover 200 and the case 100 have excellent welding quality at the corner portions 220 of the end cover 200, and the strength of the welded structure is high.

[0116] Finally, after the welding is completed, the transport mechanism 570 moves the second clamp, the case 100, and the end cover 200 to the second trimming station 560 for trimming, thus completing the welding of the end cover 200 of the battery cell 20 to the case 100.

[0117] Of course, in other embodiments, the moving directions of the four welding heads 400 may be specifically set according to actual needs, such as being surrounded to form a counterclockwise rotating circle.

[0118] 6 and 10, the movement direction of the welding head 400 (welding direction of the weld seam) can be determined according to the shape of the weld seam 400. The weld seam has a fish-scale shape, and is formed by stacking several crescent-shaped structures along the movement direction of the welding head 400. The opening direction of the crescent-shaped structures is the movement direction of the welding head 400. That is, the welding direction of the weld seam can be determined based on the opening direction of the crescent-shaped structures on the weld seam. In this way, the start and end points of the weld seam can be determined based on the welding direction of the weld seam. Here, 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 and is not limited herein.

[0119] In another embodiment of the present application, as shown in Figures 13, 17 and 18, at least one first weld seam 310 of the provided battery cell 20 includes a first weld seam sub-segment 3111 and a second weld seam sub-segment 3112, the first weld seam sub-segment 3111 and the second weld seam sub-segment 3112 are connected, and the first weld seam sub-segment 3111 and the second weld seam sub-segment 3112 are distributed along the longitudinal direction of the corresponding side 210 of the end cover 200.

[0120] The first weld seam sub-segment 3111 refers to a weld seam segment that extends along the longitudinal direction of the side portion 210 of the end cover 200.

[0121] The second weld seam sub-segment 3112 refers to another weld seam segment that extends along the length of the side 210 of the end cover 200. It should be noted here that the welding direction of the first weld seam sub-segment 3111 may be the same as or opposite to the welding direction of the second weld seam sub-segment 3112.

[0122] The first weld seam sub-segment 3111 and the second weld seam sub-segment 3112 are connected, and as can be seen, the first weld seam 310 formed by the first weld seam sub-segment 3111 and the second weld seam sub-segment 3112 is continuous without being cut, thereby realizing a sealed connection between the case 100 and the end cover 200.

[0123] For at least one first weld seam 310, for example, in the case of one battery cell 20, the first weld seam 310 in at least one side 210 of the end cover 200 adopts a structural form in which a first weld seam sub-segment 3111 and a second weld seam sub-segment 3112 are connected, and specifically, it may be two sides 210, three sides 210, or four or more sides 210.

[0124] In the battery cell 20 of the embodiment of the present application, the first weld seam 310 includes a first weld seam sub-segment 3111 and a second weld seam sub-segment 3112. Therefore, in the actual manufacturing process, the first weld seam sub-segment 3111 and the second weld seam sub-segment 3112 can be welded in two steps to obtain the first weld seam 310, which makes the welding operation of the case 100 and the end cover 200 simpler and more convenient.

[0125] In another embodiment of the present application, as shown in Figures 13, 17, and 18, the opposing and adjacent ends of the first weld seam sub-segment 3111 and the second weld seam sub-segment 3112 of the provided battery cell 20 are stacked and connected.

[0126] The adjacent ends of the first weld seam sub-segment 3111 and the second weld seam sub-segment 3112 are connected in a stacked manner, and it can be seen that the weld seam at the connection between the first weld seam sub-segment 3111 and the second weld seam sub-segment 3112 is installed in a stacked manner, that is, the connection between the first weld seam sub-segment 3111 and the second weld seam sub-segment 3112 is welded at least twice, thus increasing the weld strength at the connection between the first weld seam sub-segment 3111 and the second weld seam sub-segment 3112, reducing weld defects, improving the weld quality between the end cover 200 and the case 100, and improving the usage reliability of the battery cell 20.

[0127] 13, 17, and 18, the length of the first weld seam sub-segment 3111 of the provided battery cell 20 is longer than the stacking length of the two adjacent first weld seams 310, and the length of the second weld seam sub-segment 3112 is longer than the stacking length of the two adjacent first weld seams 310. The stacking length of the two adjacent first weld seams 310 may refer to the length of the weld seam segment where the two adjacent first weld seams 310 overlap, or may refer to the length of the weld seam at the corner portion 220 of the end cover 200.

[0128] The length of the first weld seam sub-segment 3111 is longer than the stacking length of two adjacent first weld seams 310, and as can be understood, the first weld seam sub-segment 3111 can completely cover the corner portion 220 of the end cover 200 and can be pulled out from the corner portion 220 of the end cover 200, thus reducing the connection between the first weld seam sub-segment 3111 and the second weld seam sub-segment 3112 at the corner portion 220 of the end cover 200 and improving the welding strength and welding quality of the corner portion 220 of the end cover 200.

[0129] The length of the second weld seam sub-segment 3112 is longer than the stacking length of two adjacent first weld seams 310, and as can be understood, the second weld seam sub-segment 3112 can completely cover the corner portion 220 of the end cover 200 and can be pulled out from the corner portion 220 of the end cover 200, thus reducing the connection between the first weld seam sub-segment 3111 and the second weld seam sub-segment 3112 at the corner portion 220 of the end cover 200 and improving the welding strength and welding quality of the corner portion 220 of the end cover 200.

[0130] The battery cell 20 according to the embodiment of the present application can improve the welding strength and welding quality of the corner portions 220 of the end cover 200 .

[0131] In another embodiment of the present application, as shown in Figures 13, 17 and 18, in the battery cell 20 provided, the end portion of the first weld seam sub-segment 3111 and the end portion of the second weld seam sub-segment 3112 are stacked and connected.

[0132] The end of the first weld seam sub-segment 3111 and the end of the second weld seam sub-segment 3112 are laminated together, and it can be seen that the welding end position of the first weld seam sub-segment 3111 and the welding end position of the second weld seam sub-segment 3112 are both located at the connection between the first weld seam sub-segment 3111 and the second weld seam sub-segment 3112. Thus, the welding start position of the first weld seam sub-segment 3111 and the welding start position of the second weld seam sub-segment 3112 are located at the connection between the two adjacent weld seam sub-segments of the end cover 200, respectively. In other words, the starting end of the first weld seam sub-segment 3111 and the starting end of the second weld seam sub-segment 3112 are located at the corners 220 of the end cover 200, thereby reducing the problem of poor welding such as insufficient molten pool 330 caused by the welding of two adjacent first weld seams 310 ending at the same corner 220 of the end cover 200, and both the end cover 200 and the case 100 have excellent welding quality at the corners 220 of the end cover 200, and the strength of the welded structure is high.

[0133] In another embodiment of the present application, as shown in Figures 13, 17, and 18, in the battery cell 20 provided, in the width direction of the first weld seam sub-segment 3111, the opposing and close ends of the first weld seam sub-segment 3111 and the second weld seam sub-segment 3112 are partially stacked and connected.

[0134] 19 , due to processing errors during the welding process, the center line of the welding head 400 is not aligned on the same horizontal plane when welding the side 210 of the end cover 200, and the center line B of the formed first weld seam sub-segment 3111 and the center line D of the second weld seam sub-segment 3112 are not aligned on the same horizontal plane either. As a result, the first weld seam sub-segment 3111 and the second weld seam sub-segment 3112 are vertically offset, and as a result, the adjacent first weld seam sub-segment 3111 and the second weld seam sub-segment 3112 do not completely overlap but partially overlap and then partially overlap. This results in a wider welded area between the end cover 200 and the case 100 and more reliable welding.

[0135] In one embodiment, as shown in Figures 13 to 16, the end cover 200 is rectangular and includes two long sides and two short sides, and the case 100 is a rectangular parallelepiped. When welding the end cover 200 and the case 100 using welding equipment 500, the welding equipment 500 includes a conveying mechanism 570, and the conveying mechanism 570 has 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 sequentially arranged along the conveying direction.

[0136] In the case of welding, first, the end cover 200, the electrode assembly 600 and the case 100 are assembled at the assembly station 510, whereby the end cover 200 is placed over the opening of the case 100, fixed to the first clamp, and placed with the end cover 200 facing downward, and the first clamp exposes the long side of the end cover 200 to facilitate welding of the long side.

[0137] Then, the transport mechanism 570 moves the first clamp, the case 100 fixed to the first clamp, and the end cover 200 to the first welding station 520, and then the two welding heads 400 weld the two long sides from opposite sides of the end cover 200, respectively, and the movement direction of the two welding heads 400 is the same, and both welding heads 400 move from left to right (specifically, see the directions indicated by the white arrows on the front and rear sides in Figure 13), thereby obtaining a first weld seam 310 located on the front side and a first weld seam 310 located on the rear side, and the left end of the first weld seam 310 located on the front side and the left end of the first weld seam 310 located on the rear side are both starting ends 3101, and the right end of the first weld seam 310 located on the front side and the right end of the first weld seam 310 located on the rear side are both ending ends 3102.

[0138] Thereafter, the conveying mechanism 570 continues to drive the first clamp and end cover 200 and the case 100, moving them to the first trimming station 530, and after trimming the first weld seam 310 on the long side at the first trimming station 530, the conveying mechanism 570 continues to drive the first clamp and end cover 200 and the case 100, moving them into the transfer station 540.

[0139] Thereafter, at transfer station 540, the end cover 200 and case 100 are moved to a second clamp, which exposes the two short sides of the end cover 200, thereby facilitating welding of the short sides.

[0140] Thereafter, the transport mechanism 570 continues to drive the second clamp, the case 100, and the end cover 200, and moves them to the second welding station 550. In the second welding station 550, the two welding heads 400 weld the two short side portions from opposite sides of the end cover 200, respectively. The two welding heads move in the same direction (specifically, see the directions indicated by the hollow arrows installed near the left and right end covers 200 in FIG. 13). Here, the two welding heads 400 stop welding after moving a certain distance from rear to front. At this time, the short sides of the end cover 200 are partially welded, thereby obtaining the first weld seam sub-segment 3111 located on the left side and the first weld seam sub-segment 3111 located on the right side. After that, the two welding heads 400 continue to move forward, and after moving to the front side of the end cover 200, the two welding heads 400 start welding upon receiving a command. At the same time, the two welding heads 400 move in opposite directions from front to rear (specifically, in the directions indicated by the white arrows installed far away on the left and right end covers 200 in FIG. 13). ), thereby obtaining the second weld seam sub-segment 3112 located on the left side and the second weld seam sub-segment 3112 located on the rear side, thereby completing the welding of the short side of the end cover 200, and the starting end (i.e., the rear end) of the first weld seam sub-segment 3111 located on the left side and the starting end 3101 of the first weld seam 310 located on the rear side are laminated and connected at the left rear corner 220 of the end cover 200, and the ending end of the first weld seam sub-segment 3111 located on the left side and the second weld seam sub-segment 3112 located on the left side are laminated and connected at the left rear corner 220 of the end cover 200. The end portion of the second weld seam sub-segment 3112 located on the left side is laminated and connected at the middle of the left side of the end cover 200, the start portion (i.e., the front end) of the second weld seam sub-segment 3112 located on the left side and the start portion 3101 of the first weld seam sub-segment 310 located on the front side are laminated and connected at the left front corner portion 220 of the end cover 200, and the start portion (i.e., the rear end) of the first weld seam sub-segment 3111 located on the right side and the end portion 3102 of the first weld seam 310 located on the left side are laminated and connected at the left rear corner portion 220 of the end cover 200.The end of the first weld seam sub-segment 3111 on the right side and the end of the second weld seam sub-segment 3112 on the right side are stacked and connected in the middle of the left side of the end cover 200, and the start (i.e., front) of the second weld seam sub-segment 3112 on the right side and the end 3102 of the first weld seam 310 on the front side are stacked and connected at the right front corner 220 of the end cover 200. In this way, the stacking of the end 3102 of the first weld seam 310 on the front side and the end 3102 of the first weld seam 310 on the right side at the right front corner 220 of the end cover 200 can be reduced, thereby alleviating the problem of poor welding due to the stacking of the end 3102, improving the welding quality and strength.

[0141] Finally, after the welding is completed, the transport mechanism 570 moves the second clamp, the case 100, and the end cover 200 to the second trimming station 560 for trimming, thus completing the welding of the end cover 200 of the battery cell 20 to the case 100.

[0142] During this welding process of welding the left and right edges of the end cover 200, the welding head 400 first welds a portion of the edge 210 and then stops welding early. Then, the welding head 400 continues to move forward. During the movement process, this provides time for the welding head 400 to prepare for moving in the reverse direction, and also provides time for the welding head 400 to receive a reverse movement welding operation command, thereby improving the welding efficiency between the end cover 200 and the case 100.

[0143] In another embodiment of the present application, as shown in FIG. 20 , the welded structure 300 of the provided battery cell 20 further includes at least one second weld seam 320, which extends from the terminal end 3102 of the first weld seam 310 toward the starting end 3101 of the first weld seam 310 and is covered by the first weld seam 310.

[0144] The second weld seam 320 refers to a welded structure covered by the first weld seam 310, and this welded structure 300 may be understood to be a welded structure formed by welding again based on the first weld seam 310, and this welded structure is the second weld seam 320.

[0145] The second weld seam 320 extends from the terminal end 3102 of the first weld seam 310 toward the starting end 3101 of the first weld seam 310 and is covered by the first weld seam 310. As can be seen, the second weld seam 320 is covered by the terminal end 3102 of the first weld seam 310. In this way, welding can be performed again at the terminal end 3102 of the first weld seam 310 to improve welding defects such as insufficient molten pool 330 at the terminal end 3102 of the first weld seam 310, thereby improving the welding quality of the corner portion 220 of the end cover 200 and the strength of the welded structure.

[0146] In another embodiment of the present application, as shown in FIG. 20, the starting end of the second weld seam 320 of the provided battery cell 20 is covered by the ending end 3102 of the first weld seam 310 .

[0147] The starting end of the second weld seam 320 refers to the weld seam segment formed at the start of reverse welding of the side portion 210 of the end cover 200 .

[0148] The starting end of the second weld seam 320 is covered by the ending end 3102 of the first weld seam 310. As can be understood, when welding, the welding head 400 moves along a predetermined direction to the corner portion 220 of the end cover 200 to form the first weld seam 310, and then the welding head 400 moves a certain distance in the opposite direction to perform welding, thereby obtaining the second weld seam 320. At this time, the welding material at the starting end of the second weld seam 320 can accumulate at the corner portion 220 of the end cover 200 to fill the molten pool 330 at the ending end 3102 of the first weld seam 310, thereby further improving the welding quality of the corner portion 220 of the end cover 200 and the strength of the welded structure.

[0149] In another embodiment of the present application, as shown in Figures 20, 21, and 22, the battery cell 20 provided has the second weld seam 320 partially covered by the first weld seam 310 in the width direction of the first weld seam 310.

[0150] In the width direction of the first weld seam 310, the second weld seam 320 is partially covered by the first weld seam 310. This is because, due to processing errors during the welding process, the center lines of the welding head 400 when welding the edge portion 210 of the end cover 200 are not located on the same horizontal plane, and the center lines of the formed first weld seam 310 and second weld seam 320 are also not located on the same horizontal plane. As a result, the first weld seam 310 and the second weld seam 320 are misaligned up and down. As a result, the adjacent first weld seam 310 and second weld seam 320 do not completely overlap and cover each other, but partially overlap and cover again. This results in a wider weld area between the end cover 200 and the case 100 and more reliable welding.

[0151] In another embodiment of the present application, as shown in Figures 20, 21, and 22, the second weld seam 320 is covered by at least one pair of oppositely disposed first weld seams 310 of the battery cell 20 provided.

[0152] At least one pair of oppositely disposed first weld seams 310 are covered by the second weld seam 320. As can be understood, when two welding heads 400 respectively weld two oppositely disposed side portions 210 of the end cover 200, the two welding heads 400 weld in the same direction to obtain two oppositely disposed first weld seams 310, and then simultaneously move a certain distance in opposite directions to obtain a pair of second weld seams 320. In this way, since the two welding heads 400 are controlled to move synchronously in the same direction, the welding is easy to achieve and processing and manufacturing are convenient.

[0153] With respect to at least one pair of oppositely disposed first weld seams 310, it can be understood that in one battery cell 20, one, two, three, or four or more pairs of oppositely disposed first weld seams 310 are covered by second weld seams 320, for example, as shown in FIG. 13 , one pair of oppositely disposed first weld seams 310 is covered by second weld seams 320, and the specific distribution situation can be determined according to the shape and welding path of the end cover 200 and is not limited here.

[0154] In another embodiment of the present application, as shown in FIG. 20 , the battery cell 20 provided has two adjacent first weld seams 310, with the end portion 3102 of one first weld seam 310 and the end portion 3102 of the other first weld seam 310 stacked together, and the end portion 3102 of at least one first weld seam 310 covers the start end 3101 of the second weld seam 320.

[0155] In two adjacent first weld seams 310, the end portion 3102 of one first weld seam 310 and the end portion 3102 of the other first weld seam 310 are stacked together. As can be seen, the welding of the two adjacent first weld seams 310 ends at the same corner 220. This construction may result in poor welding, such as insufficient weld pool 330, at this corner 220. However, since the end portion 3102 of at least one first weld seam 310 covers the start portion 3101 of the second weld seam 320, reverse welding is performed along the corresponding first weld seam 310 at this corner 220, thereby using the second weld seam 320 to fill the weld pool 330 at this corner 220, thereby overcoming poor welding, such as insufficient weld pool 330, and improving the strength and weld quality of the welded structure.

[0156] It can be understood that the end portion 3102 of at least one first weld seam 310 covers the beginning portion of the second weld seam 320, and the end portions 3102 of two first weld seams 310 may cover the beginning portion of any second weld seam 320, or the end portion 3102 of one first weld seam 310 may cover the beginning portion of the second weld seam 320, and this can be specifically selected according to actual needs and is not limited here.

[0157] In another embodiment of the present application, the length of the second weld seam 320 of the provided battery cell 20 is longer than the stacking length of the two adjacent first weld seams 310 .

[0158] In the battery cell 20 of the embodiment of the present application, the length of the second weld seam 320 is longer than the stacking length of two adjacent first weld seams 310, so the second weld seam 320 can completely cover the corner portion 220 of the end cover 200 and can be pulled out from the corner portion 220 of the end cover 200, thereby effectively improving the strength and weld quality of the welded structure at the corner portion 220 of the end cover 200.

[0159] In another embodiment of the present application, the length of the first weld seam 310 of the battery cell 20 provided is longer than the length of the second weld seam 320 .

[0160] In the battery cell 20 of the embodiment of the present application, the length of the first weld seam 310 is longer than the length of the second weld seam 320, so that the second weld seam 320 covers a portion of the area of ​​the first weld seam 310, and the weld length is appropriate, which is advantageous for improving production efficiency and reducing welding costs.

[0161] In another embodiment of the present application, as shown in Figures 20, 21 and 22, the first weld seam 310 of the provided battery cell 20 includes a first corner segment 3121, a first connection segment 3122, a second connection segment 3123 and a second corner segment 3124 connected in sequence, where the first corner segment 3121 and the second corner segment 3124 are respectively located at two adjacent corner portions 220 of the end cover 200, and the second weld seam 320 is covered by the second connection segment 3123 and the second corner segment 3124, where the depth of the molten pool 330 of the welded structure 300 at the second corner segment 3124 is deeper than the depth of the molten pool 330 of the welded structure 300 at the second connection segment 3123, and the depth of the molten pool 330 of the welded structure 300 at the second connection segment is deeper than the depth of the molten pool 330 of the welded structure 300 at the first connection segment 3122.

[0162] The first corner segment 3121 refers to a segment located at one of the two adjacent corner portions 220 of the end cover 200 at the first weld seam 310. For example, as shown in FIG. 20, the first corner portion 3121 refers to a segment located at the left rear corner portion 220 of the end cover 200 at the left first weld seam 310, or a segment located at the right rear corner portion 220 of the end cover 200 at the right first weld seam 310, and the first corner segment 3121 is the starting end 3101 of the first weld seam 310.

[0163] The second corner segment 3124 refers to a segment of the first weld seam 310 that is located at the other of the two adjacent corner portions 220 of the end cover 200, and this segment covers the second weld seam 320. For example, as shown in Figures 20, 21 and 22, the first corner segment 3121 refers to a segment of the left first weld seam 310 that is located at the front and rear corner portions 220 of the end cover 200, and the second corner segment 3124 is the terminal end portion 3102 of the first weld seam 310.

[0164] The second connection segment 3123 refers to a segment located between the first corner segment 3121 and the second corner segment 3124 in the first weld seam 310, and this segment covers a portion of the second weld seam 320; for example, as shown in Figures 20, 21 and 22, the second connection segment 3123 refers to a weld seam segment located in the middle of the left-hand first weld seam 310 and covering the second weld seam 320.

[0165] The first connection segment 3122 refers to a segment of the first weld seam 310 that is located between the first corner segment 3121 and the second corner segment 3124, and this segment does not cover a part of the second weld seam 320. As shown in Figures 20, 21 and 22, the first connection segment 3122 refers to a segment of the left first weld seam 310 that is located in the middle and does not cover the second weld seam 320.

[0166] The depth of the molten pool 330 of the welded structure 300 in the second corner segment 3124 is deeper than the depth of the molten pool 330 of the welded structure 300 in the second connecting segment 3123, and the depth of the molten pool 330 of the welded structure 300 in the second connecting segment 3124 is deeper than the depth of the molten pool 330 of the welded structure 300 in the first connecting segment 3122. As can be seen, the molten pool 330 of the welded structure 300 in the second corner segment 3124 is deeper, which provides better welding reliability and thereby improves the weldability of the end cover 200. The strength of the welded structure at the corner portion 220 is higher, and the depth of the molten pool 330 of the welded structure 300 at the second connection segment is deeper than the depth of the molten pool 330 of the welded structure 300 at the first connection segment 3122. The molten pool 330 of the welded structure 300 at a position close to the corner portion 220 of the end cover 200 is deeper, resulting in excellent welding reliability. As a result, the weld strength at a position close to the corner portion 220 of the end cover 200 is also high, which is advantageous for improving the welding reliability between the end cover 200 and the case 100. In addition, the welded structure 300 has one more first weld seam 310 at the second corner segment 3124 than at the second connection segment 3123, and the more weld seams there are, the deeper the weld pool 330. Therefore, the depth of the weld pool 330 of the welded structure 300 at the second corner segment 3124 is greater than the depth of the weld pool 330 of the welded structure 300 at the second connection segment 3123. The welded structure 300 has one more second weld seam 320 at the second connection segment 3123 than at the first connection segment 3122, and the more weld seams there are, the deeper the weld pool 330. Therefore, the depth of the weld pool 330 of the welded structure 300 at the second connection segment 3123 is greater than the depth of the weld pool 330 of the welded structure 300 at the first connection segment 3122.

[0167] In another embodiment of the present application, the lowest point E of the molten pool 330 of the second weld seam 320 of the battery cell 20 provided is located inside the end cover 200.

[0168] The lowest point of the molten pool 330 of the second weld seam 320 refers to the lowest point E in the depth direction of the molten pool 330, and for example, as shown in FIG. 19, the depth direction of the molten pool 330 may be the X direction.

[0169] In the battery cell 20 of the embodiment of the present application, when welding is performed from the side of the end cover 200, the lowest point of the molten pool 330 of the second weld seam 320 is located inside the end cover 200. This prevents leakage due to the welding melting through the case 100, and provides excellent sealing performance between the case 100 and the end cover 200 after welding, improving the reliability of the battery cell 20 in use.

[0170] In one embodiment, as shown in Figures 14, 15, 16 and 20, the end cover 200 is rectangular, has two long sides and two short sides, and the case 100 is a rectangular parallelepiped. When welding the end cover 200 and the case 100 using welding equipment 500, the welding equipment 500 includes a conveying mechanism 570, and the conveying mechanism 570 has 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 sequentially arranged along the conveying direction.

[0171] In the case of welding, first, the end cover 200, the electrode assembly 600 and the case 100 are assembled at the assembly station 510, whereby the end cover 200 is placed over the opening of the case 100, fixed to the first clamp, and placed with the end cover 200 facing downward, and the first clamp exposes the long side of the end cover 200 to facilitate welding of the long side.

[0172] Then, the transport mechanism 570 moves the first clamp, the case 100 fixed to the first clamp, and the end cover 200 to the first welding station 520, and then the two welding heads 400 weld the two long side portions from opposite sides of the end cover 200, respectively, the movement direction of the two welding heads 400 is the same, and the two welding heads 400 both move from left to right (specifically, see the direction indicated by the white arrows on the front and rear sides in Figure 20) to completely weld the long side portions of the end cover 200, thereby obtaining a first weld seam 310 located on the front side and a first weld seam 310 located on the rear side, and the left end of the first weld seam 310 located on the front side and the left end of the first weld seam 310 located on the rear side are both starting ends 3101, and the right end of the first weld seam 310 located on the front side and the right end of the first weld seam 310 located on the rear side are both ending ends 3102.

[0173] Thereafter, the conveying mechanism 570 continues to drive the first clamp and end cover 200 and the case 100, moving them to the first trimming station 530, and after trimming the first weld seam 310 on the long side at the first trimming station 530, the conveying mechanism 570 continues to drive the first clamp and end cover 200 and the case 100, moving them into the transfer station 540.

[0174] Thereafter, at transfer station 540, end cover 200 and case 100 are moved to a second clamp, thereby exposing the two short sides of end cover 200, thereby facilitating welding of the short sides.

[0175] Then, the transport mechanism 570 continues to drive the second clamp, the case 100, and the end cover 200 to move them to the second welding station 550. In the second welding station 550, the two welding heads 400 weld the two short side portions from opposite sides of the end cover 200, respectively. The two welding heads 400 move in the same direction (specifically, see the directions indicated by the hollow arrows installed near the left and right end covers 200 in FIG. 20). Here, the two welding heads both move from rear to front to completely weld the two short side portions. As a result, the first weld seam 310 located on the left side and the first weld seam 310 located on the rear side are obtained, and the rear end of the first weld seam 310 located on the left side and the rear end of the first weld seam 310 located on the rear side are both starting ends 3101, and the rear end of the first weld seam 310 located on the left side and the rear end of the first weld seam 310 located on the rear side are both ending ends 3102. At this time, the starting end 3101 (i.e., the first corner segment 3121) of the first weld seam 310 located on the left side and the starting end 3101 of the first weld seam 310 located on the rear side are The end cover 200 is laminated and connected at the left rear corner 220, and the end portion 3102 (i.e., the second corner segment 3124) of the first weld seam 310 located on the left side and the start portion 3101 of the first weld seam 310 located on the front side are laminated and connected at the left front corner 220 of the end cover 200, and the end portion 3101 (i.e., the first corner segment 3121) of the first weld seam 310 located on the right side and the end portion 3102 of the first weld seam 310 located on the rear side are laminated and connected at the right rear corner 220 of the end cover 200. The end portion 3102 (i.e., the second corner segment 3124) of the first weld seam 310 located on the right side and the end portion 3102 of the first weld seam 310 located on the front side are overlapped and connected at the right front corner portion 220 of the end cover 200. In order to improve the problem of poor welding caused by the overlapping of the end portion 3102, the two welding heads 400 that weld the short sides move in opposite directions from front to rear, thereby forming two second weld seams 320 on the two short sides of the end cover 200. The starting end of the second weld seam 320 located on the left side isThe end portion 3102 (i.e., the second corner segment 3124) of the first weld seam 310 located on the left side is covered by the second connecting segment 3123, and the start portion of the second weld seam 320 located on the right side is covered by the end portion 3102 (i.e., the second corner segment 3124) of the first weld seam 310 located on the right side and the second connecting segment 3123, thereby improving the problem of poor welding at the right front corner portion 220 of the end cover 200, improving the welding quality, and increasing the welding strength.

[0176] Finally, after the welding is completed, the transport mechanism 570 moves the second clamp, the case 100, and the end cover 200 to the second trimming station 560 for trimming, thus completing the welding of the end cover 200 of the battery cell 20 to the case 100. During this welding process, the movement directions of the two welding heads 400 are the same, and the movement control of the welding heads 400 can be achieved simply and easily.

[0177] In another embodiment of the present application, as shown in FIGS. 10, 17 and 21, the welding structure 300 of the battery cell 20 provided is located on the side of the end cover 200.

[0178] The welding structure 300 is located on the side of the end cover 200, and as can be seen, the end cover 200 and the case 100 are welded using a side welding method, in which the welding head 400 welds the front, rear, left and right sides of the end cover 200. This welding method is simple, convenient and easy to implement. Of course, in other embodiments, the end face and the case 100 may also be welded using a top welding method, i.e., the welding structure 300 is located on the top surface of the end cover 200.

[0179] In another embodiment of the present application, as shown in FIGS. 6, 13 and 20, the corner portions 220 of the end covers 200 of the battery cells 20 provided are arc-shaped.

[0180] The corners 220 of the end cover 200 are arc-shaped, and as can be seen, the portions of the case 100 corresponding to the corners 220 of the end cover 200 are also arc-shaped, which allows for a smoother transition of the edges of the battery cells 20 and improves the reliability of the battery cells 20 in use. Furthermore, because the corners 220 of the end cover 200 are arc-shaped, during welding, the corners 220 can be welded when the welding head 400 moves linearly along one side 210 of the end cover 200 to weld the corners 220. At the same time, the corners 220 can be welded again when the welding head 400 moves linearly along the side 210 adjacent to the side 210 on the end cover 200 to weld the corners 220. As a result, the two adjacent first weld seams 310 are stacked at the corners 220, which simplifies the movement path of the welding head 400 and is advantageous for improving welding efficiency.

[0181] In another embodiment, the corners 220 of the end cover 200 are arcuate, elliptical, or the like.

[0182] In another embodiment of the present application, as shown in FIG. 23, a protrusion 230 is formed on the end cover 200 of the battery cell 20 provided, and the protrusion 230 is inserted into the case 100 through an opening.

[0183] The protrusion 230 refers to a protrusion structure constructed on the end cover 200 toward the inner surface of the case 100. This protrusion structure can be inserted into the case 100, and the positioning effect between the outer wall of the protrusion 230 and the inner wall of the case 100 allows the end cover 200 to be stably fixed to the case 100, improving the subsequent welding accuracy. Furthermore, during the laser welding process, the protrusion 230 can block the laser emitted from the welding head 400, reducing the risk of laser leakage.

[0184] In another embodiment of the present application, the range of 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 cover 200 is 0.1 mm to 0.5 mm.

[0185] In the battery cell 20 of the embodiment of the present application, the distance L between the outer peripheral wall of the protrusion 230 and the outer peripheral wall of the end cover 200 is set within the above range, thereby enabling the case 100 and the end cover 200 to be stably and reliably welded, and the strength of the welded structure is high. If this distance L is set too small, the case 100 will protrude too far outside the end cover 200, causing poor welding, and if the distance L is set too large, the edge of the end cover 200 will protrude too far outside the case 100, causing poor welding. Here, the distance L may be 0.1 mm, 0.12 mm, 0.14 mm, 0.16 mm, 0.18 mm, 0.2 mm, 0.22 mm, 0.24 mm, 0.26 mm, 0.28 mm, 0.3 mm, 0.32 mm, 0.34 mm, 0.36 mm, 0.38 mm, 0.4 mm, 0.42 mm, 0.44 mm, 0.46 mm, 0.48 mm, or 0.5 mm.

[0186] In another embodiment of the present application, a battery is provided that includes the battery cell 20 described above.

[0187] The battery of the embodiment of the present application employs the above-mentioned battery cell 20, and the strength of the welding structure between the case 100 and the end cover 200 of the battery cell 20 is high, which improves the reliability of use of the battery cell 20 and the reliability and performance of the battery. The battery of the embodiment of the present application employs all the technical solutions of all the above-mentioned embodiments, and therefore has all the beneficial effects of the technical solutions of the above-mentioned embodiments, and they will not be described one by one here.

[0188] In another embodiment of the present application, there is provided a power consuming device including the battery described above.

[0189] The power consumption device of the embodiment of the present application employs the above battery, which has excellent reliability and performance in use, and is also advantageous in improving the performance and reliability of the power consumption device. The power consumption device of the embodiment of the present application employs all the technical solutions of all the above embodiments, and therefore has all the beneficial effects of the technical solutions of the above embodiments, and they will not be described one by one here.

[0190] The above are only preferred embodiments of the present application and are not intended to limit the present application. All modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application. [Explanation of symbols]

[0191] Here, the symbols in the figure are as follows: 1000: vehicle, 1100: battery, 1200: controller, 1300: motor, 10: housing, 11: first part, 12: second part, 20: battery cell, 100: Case, 200: End cover, 210: Side portion, 220: Corner portion, 230: Protrusion portion, 241: electrode terminal, 242: pressure release mechanism, 300: Welded structure, 310: first weld seam, 320: second weld seam, 330: molten pool, 3111: first weld seam sub-segment; 3112: second weld seam sub-segment; 3121: first corner segment, 3122: first connection segment, 3123: second connection segment, 3124: second corner segment, 3101: starting end, 3102: ending end, 400: welding head, 500: welding equipment, 510: assembly station, 520: first welding station, 530: first trimming station, 540: transfer station, 550: second welding station, 560: second trimming station, 570: transport mechanism. 600: Electrode assembly.

Claims

1. A battery cell, a case having an opening; an end cover, the end cover being welded to the opening to form a welded structure, the welded structure including a plurality of first weld seams, the first weld seams being located corresponding to edges of the end cover, the plurality of first weld seams being connected to form a closed annular structure and being located on the outer periphery of the end cover; Here, two adjacent first weld seams are stacked and connected at corresponding corner portions of the end cover.

2. The battery cell according to claim 1 , wherein two adjacent first weld seams in a width direction of the first weld seams partially overlap at corner portions of the end cover.

3. 3. The battery cell according to claim 1, wherein a starting end of one of the first weld seams and a terminal end of the other of the first weld seams are connected in a stacked manner in two adjacent first weld seams.

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 seam is located inside the end cover.

5. The battery cell according to any one of claims 1 to 4, wherein the depth of the molten pool of the welded structure at the corner portion of the end cover is deeper than the depth of the molten pool of the welded structure at other portions.

6. 6. The battery cell according to claim 1, wherein at least one of the first weld seams includes a first weld seam sub-segment and a second weld seam sub-segment that are connected to each other, and the first weld seam sub-segment and the second weld seam sub-segment are distributed along the longitudinal direction of the corresponding side portion of the end cover.

7. The battery cell of claim 6 , wherein the opposed adjacent ends of the first weld seam sub-segment and the second weld seam sub-segment are stacked and connected.

8. 8. The battery cell of claim 7, wherein a length of the first weld seam sub-segment is longer than a stack length of two adjacent first weld seams, and a length of the second weld seam sub-segment is longer than a stack length of two adjacent first weld seams.

9. The battery cell according to claim 8 , wherein the end of the first weld seam sub-segment and the end of the second weld seam sub-segment are connected in a stacked manner.

10. The battery cell according to any one of claims 7 to 9, wherein ends of the first weld seam sub-segment and the second weld seam sub-segment that are close to each other in a width direction of the first weld seam sub-segment are partially stacked and connected.

11. 9. The battery cell according to claim 1, wherein the welded structure further includes at least one second weld seam, the second weld seam extending from an end portion of the first weld seam toward an initial end portion of the first weld seam and being covered by the first weld seam.

12. The battery cell according to claim 11 , wherein a starting end of the second weld seam is covered by a terminal end of the first weld seam.

13. 13. The battery cell according to claim 11, wherein the second weld seam is partially covered by the first weld seam in a width direction of the first weld seam.

14. The battery cell according to any one of claims 11 to 13, wherein the second weld seam is covered by at least one pair of the first weld seams that are disposed opposite each other.

15. 15. The battery cell according to claim 11, wherein an end portion of one of the first weld seams and an end portion of the other of the first weld seams are stacked on top of each other, and a start end portion of the second weld seam is covered by the end portion of at least one of the first weld seams.

16. The battery cell according to any one of claims 11 to 15, wherein a length of the second weld seam is longer than a stack length of two adjacent first weld seams.

17. The battery cell according to any one of claims 11 to 16, wherein the length of the first weld seam is longer than the length of the second weld seam.

18. the first weld seam includes a first corner segment, a first connecting segment, a second connecting segment, and a second corner segment, which are connected in sequence, the first corner segment and the second corner segment being located at two adjacent corner portions of the end cover, respectively, and the second weld seam is covered by the second connecting segment and the second corner segment; A battery cell as described in any one of claims 11 to 17, wherein the depth of the molten pool of the welding structure in the second corner segment is deeper than the depth of the molten pool of the welding structure in the second connection segment, and the depth of the molten pool of the welding structure in the second connection segment is deeper than the depth of the molten pool of the welding structure in the first connection segment.

19. The battery cell according to any one of claims 11 to 18, wherein the lowest point of the molten pool of the second weld seam is located inside the end cover.

20. The battery cell according to any one of claims 1 to 19, wherein the welded structure is located on a side surface of the end cover.

21. The battery cell according to any one of claims 1 to 20, wherein the corner portions of the end cover are arc-shaped.

22. The battery cell according to any one of claims 1 to 21, wherein the end cover is provided with a protrusion, and the protrusion is inserted into the case through the opening.

23. The battery cell according to claim 22, wherein the range of the gap between the outer peripheral wall of the protrusion and the outer peripheral wall of the end cover is 0.1 mm to 0.5 mm.

24. A battery comprising the battery cell according to any one of claims 1 to 23.

25. 25. A power consuming device comprising the battery of claim 24.

Images