Battery cell and manufacturing method therefor, battery device and electric device

Abstract

Disclosed in the present disclosure are a battery cell and a manufacturing method therefor, a battery device, and an electric device. The battery cell comprises a casing and an electrode assembly, wherein the casing comprises a casing body and an end cover, the casing body having an opening, the end cover sealing the opening and enclosing an accommodating cavity with the casing body, and the end cover being welded to the casing body from the outer peripheral side of the end cover to form a weld seam; the electrode assembly is accommodated in the accommodating cavity; and the surface of the end cover facing away from the accommodating cavity includes a first surface, a first protrusion is formed on at least part of the edge of the first surface, the surface of the first protrusion facing away from the accommodating cavity is a protruding end face, and there is a gap in the direction of thickness of the end cover between the protruding end face and the junction area of the weld seam and the end cover.

Description

Battery cells and their manufacturing methods, battery devices and electrical devices

[0001] Cross-references to related applications

[0002] This disclosure is based on and claims priority to Chinese Patent Application No. 202411045787.3, filed on July 31, 2024, entitled “Battery Cell and Manufacturing Method Thereof, Battery Device and Power-Using Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of battery technology, and in particular to battery cells and their manufacturing methods, battery devices and power-consuming devices. Background Technology

[0004] The application of new energy batteries in daily life and industry is becoming increasingly widespread. For example, new energy vehicles equipped with batteries are already widely used, and batteries are also increasingly being applied in energy storage. In new energy vehicles equipped with batteries, the batteries can provide all or part of the power. In the field of energy storage, batteries can be installed in energy storage boxes or directly on the user side.

[0005] The structural strength of a battery directly affects its lifespan and mechanical stability; therefore, improving battery structural strength is one of the key research topics in the industry. Furthermore, the industry is continuously demanding higher volumetric energy density from batteries. Summary of the Invention

[0006] To address the aforementioned technical problems, this disclosure provides a battery cell with high volumetric energy density and high structural strength, a method for manufacturing the same, a battery device, and an electrical device thereof.

[0007] This disclosure is achieved through the following technical solution.

[0008] A first aspect of this disclosure provides a battery cell, comprising: a housing including a casing and an end cap, the casing having an opening, the end cap closing the opening and forming a receiving cavity with the casing, the end cap being welded to the casing from the outer peripheral side of the end cap to form a weld; an electrode assembly received within the receiving cavity; wherein the surface of the end cap facing away from the receiving cavity includes a first surface, at least a portion of the edge of the first surface forming a first protrusion, the surface of the first protrusion facing away from the receiving cavity being a raised end face, and the junction area between the weld and the end cap and the raised end face being spaced apart in the thickness direction of the end cap.

[0009] In the embodiments of this disclosure, by providing a first protrusion at the edge of the first surface of the end cap, when welding from the outer periphery of the end cap, the distance between the protruding end face of the first protrusion and the welding center is large, making it difficult for the weld to melt to the protruding end face of the first protrusion during welding. Furthermore, the junction area between the weld and the end cap and the protruding end face are spaced apart in the thickness direction of the end cap, that is, the weld width does not exceed the outer surface of the end cap, thereby improving the reliability of the weld and thus improving the structural strength of the battery cell. Moreover, by providing the first protrusion only at the edge of the end cap, the thickness of the remaining part of the end cap is still relatively thin, which is beneficial to improving the volumetric energy density of the battery cell.

[0010] In some embodiments, the end cap is made of at least one of steel, titanium alloy, and copper alloy; the housing is made of at least one of steel, titanium alloy, and copper alloy.

[0011] The end caps and housings made of the aforementioned materials have high structural strength, which is beneficial for improving the structural strength of the battery cell. However, the end caps and housings made of these materials require high welding power during welding, which can easily cause the weld to extend to the outer surface of the end cap. Therefore, in this embodiment, a first protrusion is provided at the edge of the first surface of the end cap. When welding from the outer periphery of the end cap, the distance between the protruding end face of the first protrusion and the welding center is large, making it less likely for the weld to melt to the protruding end face of the first protrusion during welding. Furthermore, the junction area between the weld and the end cap and the protruding end face are spaced apart in the thickness direction of the end cap; that is, the weld width does not exceed the outer surface of the end cap, thereby improving the reliability of the weld and thus enhancing the structural strength of the battery cell.

[0012] In some embodiments, along the thickness direction of the end cap, the minimum distance between the junction area of ​​the weld and the end cap and the raised end face is in the range of 0.2 mm to 2.5 mm.

[0013] In this way, by limiting the minimum distance between the junction area of ​​the weld and the end cap and the raised end face to the range of 0.2mm to 2.5mm, the position of the weld is appropriate, so that it will not exceed the raised end face and will not easily extend into the inner surface of the end cap, thereby improving the reliability of the weld and the structural strength of the battery cell.

[0014] In some embodiments, the end cap's surface facing the receiving cavity includes a second surface, and the junction region between the weld and the end cap and the second surface of the end cap are spaced apart along the thickness direction of the end cap.

[0015] This ensures that the weld does not extend beyond the second surface of the end cap, improving the reliability of the weld. Furthermore, it prevents the weld from extending into the housing cavity of the outer casing, thus protecting the electrode assembly within the housing cavity and reducing the risk of short circuits caused by punctures to the battery cells' electrode assemblies.

[0016] In some embodiments, the minimum distance between the junction area of ​​the weld and the end cap and the second surface of the end cap along the thickness direction of the end cap is in the range of 0.25 mm to 2.5 mm.

[0017] In this way, by limiting the minimum distance between the junction area of ​​the weld and the end cap and the second surface to within the range of 0.25mm to 2.5mm, the position of the weld is appropriate, neither exceeding the raised end face nor extending into the inner side of the end cap beyond the second surface of the end cap, thereby improving the reliability of the weld, increasing the structural strength of the battery cell, and reducing the risk of short circuit in the battery cell.

[0018] In some embodiments, the distance between the second surface of the end cap and the first surface is in the range of 0.4 mm to 2.5 mm.

[0019] The first protrusion makes it difficult for the protruding end face of the first protrusion to melt during welding, thus the thickness of the end cap can be reduced. Therefore, the thickness of the end cap is set between 0.4mm and 2.5mm, which will not affect the reliability of the welding, but also reduce the space occupied and improve the volumetric energy density of the battery cell.

[0020] In some embodiments, the distance between the second surface of the end cap and the first surface is in the range of 0.8 mm to 1 mm.

[0021] The first protrusion makes it difficult for the protruding end face of the first protrusion to melt during welding, thus the thickness of the end cap can be reduced. Therefore, the thickness of the end cap is set between 0.8mm and 1mm, which will not affect the reliability of the welding, but also reduce the space occupied and improve the volumetric energy density of the battery cell.

[0022] In some embodiments, an arcuate transition surface is formed between the second surface of the end cap and the weld, and there is a gap between the junction area of ​​the weld and the end cap and the arcuate transition surface along the thickness direction of the end cap.

[0023] The weld seam and the end cap are separated by an arc-shaped transition surface, which allows the weld seam to avoid the arc-shaped transition surface where the edge is prone to collapse. This prevents the weld seam from being welded into the collapse area and thus avoids missing material during the welding process, thereby improving the reliability of the weld and further enhancing the structural strength of the battery cell.

[0024] In some embodiments, the size of the arcuate transition surface along the thickness direction of the end cap is in the range of 0.05 mm to 0.025 mm.

[0025] Thus, the size of the arc-shaped transition surface is smaller, and correspondingly, the area of ​​the flat surface in the first recess is larger, which increases the area of ​​the first recess and the shell to fit together, thereby further improving the welding reliability of the end cap and the shell.

[0026] In some embodiments, at least a portion of the edge of the second surface of the end cap is formed with a first recess, and one end of the housing having an opening engages with the first recess and is welded to the first recess.

[0027] The first recess of the end cap engages with the end of the housing, which increases the contact area between the end cap and the housing, thereby improving the welding reliability of the end cap and the housing. Moreover, since the end of the housing is engaged with the first recess, the welding center of the end cap and the housing is offset from the side of the second surface facing the first surface during welding. This results in the weld seam being located between the second surface and the raised end face, thereby improving the welding reliability, increasing the structural strength of the battery cell, and reducing the risk of short circuit in the battery cell.

[0028] In some embodiments, the first recess and the first protrusion of the end cap are formed by stamping from one side of the second surface.

[0029] During the process of stamping the first recessed portion from one side of the raw material sheet for manufacturing the end cap, since the end cap mold has a recessed structure on the other side facing the raw material sheet that allows material to avoid it, some material is squeezed into the recessed structure on the end cap mold during the process of the raw material sheet being stamped inward, which reduces the stamping pressure generated on the end cap mold. In this way, the impact force on the end cap mold during stamping can be reduced, the service life of the end cap mold can be extended, and thus the manufacturing cost of the battery cell can be reduced.

[0030] In addition, during the process of the raw material sheet being stamped and recessed inward, some material is squeezed to avoid the recessed structure on the end cap mold, which reduces the stamping pressure generated by the end cap mold. Therefore, the reaction force of the end cap mold on the raw material sheet is also reduced accordingly. This helps to reduce the probability that the inner surface of the first recessed part will deform due to the reaction force of the end cap mold, thus helping to control the radius of the arc transition surface within a small range, and further improving the reliability of the engagement between the inner surface of the first recessed part and the end of the shell.

[0031] In some embodiments, the dimension of the first recess along the thickness direction of the end cap is in the range of 0.15 mm to 1.5 mm.

[0032] In this way, the size of the first recess along the thickness direction of the end cap is limited to the range of 0.15mm to 1.5mm, so that the first recess and the shell fit together more securely without taking up too much space.

[0033] In some embodiments, the dimension of the first recess along the thickness direction of the end cap is in the range of 0.35 mm to 0.75 mm.

[0034] In this way, the size of the first recess along the thickness direction of the end cap is limited to the range of 0.35mm to 0.75mm, so that the first recess and the shell fit together more securely without taking up too much space.

[0035] In some embodiments, a first protrusion and a first surface of the end cap define a recessed region, and the battery cell further includes an electrode post disposed in the recessed region of the end cap and connected to an electrode assembly.

[0036] The electrode post is located in the recessed area of ​​the end cap, which reduces the space occupied by the entire battery cell in the thickness direction of the end cap, thereby improving the volumetric energy density of the battery cell.

[0037] In some embodiments, the outer surface of the housing is covered with a protective film that covers at least a portion of the first protrusion.

[0038] The protective film is designed to insulate and protect the outer casing, extending the lifespan of individual battery cells.

[0039] In some embodiments, the housing includes a base plate and a side plate surrounding the base plate, an end cap is connected to the side plate and is opposite to the base plate along the thickness direction of the end cap, and a weld protrudes from the outer surface of the side plate in a direction perpendicular to the outer surface of the side plate by a dimension smaller than the thickness of the protective film.

[0040] In this way, the weld seam extends beyond the side plate by less than the thickness of the protective film, making it less likely for the protective film covering the outer periphery of the side plate to be punctured by the weld seam, thereby improving the protective effect of the protective film.

[0041] In some embodiments, the weld penetration depth is not less than the thickness of the side plate; and / or, the weld width is not less than 0.3 mm.

[0042] Thus, by setting the weld penetration depth to be no less than the thickness of the side plate, the welding strength of the side plate and end cap is improved, and the reliability of the connection is enhanced. Setting the weld width to be no less than 0.3 mm improves the welding quality, thereby further enhancing the reliability of the connection between the side plate and end cap.

[0043] In some embodiments, the wall thickness of the casing is in the range of 0.05 mm to 5 mm. A second aspect of this disclosure provides a battery device comprising: at least one of the above-described battery cells.

[0044] Since the battery device includes the battery cell provided in the first aspect, and the battery cell has high structural strength and high volumetric energy density, the battery device has both high structural strength and high volumetric energy density.

[0045] A third aspect of this disclosure provides an electrical device that includes the aforementioned battery cell or battery device for providing electrical energy.

[0046] Since the battery device includes a battery cell provided by the first aspect or a battery device provided by the second aspect, and the battery cell and battery device have high structural strength and high volumetric energy density, the power device has high structural strength and high volumetric energy density.

[0047] The fourth aspect of this disclosure provides a method for manufacturing a battery cell, comprising:

[0048] Provide housing, end caps and electrode assemblies;

[0049] Install the electrode assembly into the housing;

[0050] The end cap is welded to the housing from the outer periphery, so that the end cap closes the opening of the housing;

[0051] The surface of the end cap facing away from the receiving cavity includes a first surface, at least a portion of the edge of the first surface is formed with a first protrusion, the surface of the first protrusion facing away from the receiving cavity is a raised end face, and the junction area between the weld and the end cap and the raised end face are spaced apart in the thickness direction of the end cap.

[0052] In the embodiments of this disclosure, by providing a first protrusion at the edge of the first surface of the end cap, when welding from the outer periphery of the end cap, the distance between the protruding end face of the first protrusion and the welding center is large, making it difficult for the weld to melt to the protruding end face of the first protrusion during welding. Furthermore, the junction area between the weld and the end cap and the protruding end face are spaced apart in the thickness direction of the end cap, that is, the weld width does not exceed the outer surface of the end cap, thereby improving the reliability of the weld and thus improving the structural strength of the battery cell. Moreover, by providing the first protrusion only at the edge of the end cap, the thickness of the remaining part of the end cap is still relatively thin, which is beneficial to improving the volumetric energy density of the battery cell.

[0053] In some embodiments, prior to providing the housing, end caps, and electrode assembly, the following are also included:

[0054] Provide raw material boards;

[0055] Place the raw material sheet into the end cap mold;

[0056] The raw material sheet is stamped from the first side to form the first structure;

[0057] The first structure is cut to form an end cap;

[0058] The end cap's surface facing the first side includes a second surface, at least a portion of the edge of the second surface having a first recess formed by a stamping operation, and the end cap's surface facing away from the first side includes a first surface, at least a portion of the edge of the first surface having a first protrusion formed by a stamping operation.

[0059] During the process of stamping the first recessed portion from one side of the raw material sheet for manufacturing the end cap, since the end cap mold has a recessed structure on the other side facing the raw material sheet that allows material to avoid it, some material is squeezed into the recessed structure on the end cap mold during the process of the raw material sheet being stamped inward, which reduces the stamping pressure generated on the end cap mold. In this way, the impact force on the end cap mold during stamping can be reduced, the service life of the end cap mold can be extended, and thus the manufacturing cost of the battery cell can be reduced.

[0060] In addition, during the process of the raw material sheet being stamped and recessed inward, some material is squeezed to avoid the recessed structure on the end cap mold, which reduces the stamping pressure generated by the end cap mold. Therefore, the reaction force of the end cap mold on the raw material sheet is also reduced accordingly. This helps to reduce the probability that the inner surface of the first recessed part will deform due to the reaction force of the end cap mold, thus helping to control the radius of the arc transition surface within a small range, and further improving the reliability of the engagement between the inner surface of the first recessed part and the end of the shell.

[0061] Invention Effects

[0062] This disclosure provides a battery cell with high volumetric energy density and high structural strength, a method for manufacturing the same, a battery device, and an electrical device thereof. Attached Figure Description

[0063] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this disclosure. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0064] Figure 1 is a schematic diagram of the vehicle structure provided in some embodiments of this disclosure;

[0065] Figure 2 is a three-dimensional exploded view of a battery provided in some embodiments of this disclosure;

[0066] Figure 3 is a three-dimensional structural diagram of a battery cell provided in some embodiments of this disclosure;

[0067] Figure 4 is an exploded perspective view of a battery cell provided in some embodiments of this disclosure;

[0068] Figure 5 is a cross-sectional view of a battery cell provided in some embodiments of this disclosure;

[0069] Figure 6 is an enlarged view of the weld seam shown at point A in Figure 5;

[0070] Figure 7 is an enlarged view of the structure at point A in Figure 5, where the weld is not shown;

[0071] Figure 8 is a cross-sectional view of the end cap of a battery cell provided in some embodiments of this disclosure;

[0072] Figure 9 is an enlarged view of the structure at point B in Figure 8;

[0073] Figure 10 is a first flowchart of a battery cell manufacturing method provided in some embodiments of the present disclosure;

[0074] Figure 11 is a second flowchart of a battery cell manufacturing method provided in some embodiments of this disclosure.

[0075] Explanation of reference numerals in the attached drawings: 1000 Vehicle; 100 Battery pack; 200 Controller; 300 Motor; 10 Battery box; 101 Box cover; 102 Box body; 20 Battery cell; 1 Outer shell; 11 End cap; 111 Second surface; 112 First recess; 113 First surface; 114 First protrusion; 1141 Protruding end face; 115 Transition surface; 12 Housing; 121 Base plate; 122 Side plate; 1221 First shell plate; 1222 Second shell plate; 13 Weld; 14 Terminal post; 15 Pressure relief mechanism; 16 Adapter piece; 17 End cap patch; 2 Electrode assembly; 21 Tab; 3 Protective film. Detailed Implementation

[0076] The embodiments of the technical solutions disclosed herein will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solutions disclosed herein and are therefore intended to limit the scope of protection of this disclosure.

[0077] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure; the terms “comprising” and “having”, and any variations thereof, in the specification and the foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0078] In the description of the embodiments of this disclosure, technical terms such as "first," "second," and "third" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "a plurality of" means two or more, unless otherwise explicitly defined.

[0079] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0080] In the description of the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects are in an "or" relationship.

[0081] In the description of the embodiments of this disclosure, the technical terms "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "circumferential," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, operated, or used in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this disclosure.

[0082] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0083] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, the technical term "contact" should be interpreted broadly, and can be direct contact, contact through an intermediate medium layer, contact between two contacting parties with substantially no interaction force, or contact between two contacting parties with interaction force.

[0084] The following is a detailed description of this disclosure.

[0085] Currently, new energy batteries are being used more and more widely in daily life and industry. They are not only used in energy storage systems for hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of the application areas of power batteries, the market demand is also constantly increasing.

[0086] Typically, the electrode assembly of a battery cell is housed within a cavity enclosed by a casing and end caps, which are connected by side welding. In existing technologies, due to the relatively thin thickness of the end caps, inaccurate welding positioning during the welding process can easily lead to melting of the outer surface of the end cap, resulting in weld width exceeding the outer surface of the end cap and causing poor welding, thus affecting the structural strength of the battery cell. Furthermore, to reduce the likelihood of this occurring, the thickness of the end cap is usually increased. However, this increases the volume of the battery cell, which is detrimental to improving volumetric energy density.

[0087] The inventors of this disclosure discovered through research that forming a raised structure on the edge of the outer surface of the end cap of the battery cell provides a sufficiently thick material for welding the end cap, so that the material does not melt to the outer surface of the end cap during the welding process between the end cap and the casing. That is, the weld width does not exceed the outer surface of the end cap, thereby improving the reliability of the weld and providing structural strength to the battery cell. Moreover, by setting the raised structure only on the edge of the end cap, the thickness of the rest of the end cap remains relatively thin, which is beneficial to improving the volumetric energy density of the battery cell.

[0088] Based on this design concept, the inventors of this disclosure have designed a battery cell, which includes a casing and an electrode assembly. The casing includes a housing and an end cap. The housing has an opening, and the end cap closes the opening and forms a receiving cavity with the housing. The end cap is welded to the housing from the outer periphery of the end cap to form a weld. The electrode assembly is received in the receiving cavity. The surface of the end cap facing away from the receiving cavity includes a first surface. At least a portion of the edge of the first surface forms a first protrusion. The surface of the first protrusion facing away from the receiving cavity is a raised end face. The junction area between the weld and the end cap and the raised end face are spaced apart in the thickness direction of the end cap.

[0089] By providing a first protrusion at the edge of the first surface of the end cap, when welding from the outer periphery of the end cap, the distance between the raised end face of the first protrusion and the welding center is relatively large, making it difficult for the weld to melt to the raised end face of the first protrusion during welding. Furthermore, the junction area between the weld and the end cap and the raised end face are spaced apart in the thickness direction of the end cap, that is, the weld width does not exceed the outer surface (including the first surface and the raised end face), thereby improving the reliability of the weld and thus improving the structural strength of the battery cell. Moreover, by providing the first protrusion only at the edge of the end cap, the thickness of the rest of the end cap remains relatively thin, which is beneficial to improving the volumetric energy density of the battery cell.

[0090] In this disclosure, "multiple" means two or more.

[0091] The battery cells provided in this disclosure can be grouped into multiple groups to form a battery cell assembly, used to provide voltage and capacity. Multiple battery cells in a battery cell assembly can be connected in series, parallel, or in a mixed configuration via a busbar.

[0092] The battery cells provided in this disclosure can be applied to battery devices, which may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or in a mixed configuration via a busbar.

[0093] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0094] In some embodiments, the battery device may be a battery pack, which includes a battery case and one or more individual battery cells housed within the battery case.

[0095] As an example, a battery cell assembly can be a battery module, which can be housed in a battery case by fixing the battery module in the battery case.

[0096] As an example, battery cell assemblies can also be housed in a battery box by directly fixing multiple battery cells to the battery box.

[0097] In some embodiments, the battery device refers to an energy storage device, which includes a battery box having a door on at least one side. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0098] The technical solutions described in this disclosure are applicable to various electrical devices that use battery cells and battery devices, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0099] In the following embodiments, for ease of explanation, a vehicle 1000 is used as an example of an electrical device according to an embodiment of this disclosure. The description is as follows, in conjunction with the accompanying drawings.

[0100] Figure 1 is a structural schematic diagram of a vehicle 1000 provided in some embodiments of this disclosure.

[0101] Vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. As shown in Figure 1, a battery pack 100 is installed inside vehicle 1000. The battery pack 100 can be located at the bottom, front, or rear of vehicle 1000. The battery pack 100 can be used to power vehicle 1000; for example, it can serve as the operating power source for vehicle 1000. Vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 controls the battery pack 100 to supply power to the motor 300, for example, to meet the power needs of vehicle 1000 during starting, navigation, and driving.

[0102] In some embodiments of this disclosure, the battery pack 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0103] Figure 2 is an exploded perspective view of the battery pack 100 provided in an embodiment of this disclosure.

[0104] As shown in Figure 2, the battery pack 100 includes a battery box 10 and at least one battery cell 20. The battery box 10 has a receiving space, and at least one battery cell 20 is received in the receiving space.

[0105] In some embodiments of this disclosure, the battery box 10 includes a box body 102 and a box cover 101, with the box cover 101 covering the box body 102, thereby forming an accommodating space between the box body 102 and the box cover 101.

[0106] The housing 102 can be a hollow structure with one open end, and the cover 101 can be a plate-like structure. The cover 101 closes onto the open side of the housing 102 so that the cover 101 and the housing 102 together define the receiving space. Alternatively, both the cover 101 and the housing 102 can be hollow structures with one open side, and the open side of the cover 101 closes onto the open side of the housing 102. Of course, the battery box 10 formed by the cover 101 and the housing 102 can be of various shapes, such as a cylinder, a cuboid, etc.

[0107] In the battery pack 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the entire assembly of multiple battery cells 20 is placed in the receiving space formed by the housing 102 and the cover 101. Alternatively, the battery pack 100 can also be composed of multiple battery cells 20 first connected in series, parallel, or in a mixed configuration to form battery modules, and then these battery modules are connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the receiving space formed by the housing 102 and the cover 101. The battery pack 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0108] In this embodiment of the disclosure, the battery cell 20 can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0109] The battery cell 20 can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this embodiment does not limit it.

[0110] Hereinafter, some embodiments of the present disclosure will be described in detail with reference to Figures 3 to 10.

[0111] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of the present disclosure; Figure 2 is a three-dimensional exploded schematic diagram of a battery provided in some embodiments of the present disclosure; Figure 3 is a three-dimensional structural schematic diagram of a battery cell provided in some embodiments of the present disclosure; Figure 4 is a three-dimensional exploded view of a battery cell provided in some embodiments of the present disclosure; Figure 5 is a cross-sectional view of a battery cell provided in some embodiments of the present disclosure; Figure 6 is an enlarged view of the structure at point A in Figure 5 showing the weld; Figure 7 is an enlarged view of the structure at point A in Figure 5 without showing the weld; Figure 8 is a cross-sectional view of the end cap of a battery cell provided in some embodiments of the present disclosure; Figure 9 is an enlarged view of the structure at point B in Figure 8.

[0112] The first aspect of this disclosure provides a battery cell 20, as shown in Figures 3 to 6. The battery cell 20 includes a housing 1 and an electrode assembly 2. The housing 1 includes a shell 12 and an end cap 11. The shell 12 has an opening, and the end cap 11 closes the opening and forms a receiving cavity with the shell 12. The end cap 11 is welded to the shell 12 from the outer peripheral side of the end cap 11 to form a weld 13. The electrode assembly 2 is received in the receiving cavity. The surface of the end cap 11 facing away from the receiving cavity includes a first surface 113. At least a portion of the edge of the first surface 113 forms a first protrusion 114. The surface of the first protrusion 114 facing away from the receiving cavity is a raised end face 1141. The junction area between the weld 13 and the end cap 11 and the raised end face 1141 are spaced apart in the thickness direction X of the end cap 11.

[0113] Electrode assembly 2 is the component in the battery cell 20 where the electrochemical reaction occurs. The casing 1 may contain one or more electrode assemblies 2. Electrode assembly 2 includes a cathode electrode, an anode electrode, and a separator. The battery cell primarily operates by the movement of metal ions between the cathode and anode electrodes. The cathode electrode includes a cathode current collector and a cathode active material layer, the cathode active material layer being coated on the surface of the cathode current collector; the cathode current collector includes a cathode current collector portion and a cathode protrusion extending from the cathode current collector portion, the cathode current collector portion being coated with the cathode active material layer, and at least a portion of the cathode protrusion not being coated with the cathode active material layer, the cathode protrusion serving as a cathode tab. Taking a lithium-ion battery as an example, the cathode current collector material can be aluminum, and the cathode active material layer includes cathode active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The anode electrode includes an anode current collector and an anode active material layer, the anode active material layer being coated on the surface of the anode current collector. The anode current collector includes an anode current collection portion and an anode protrusion protruding from the anode current collection portion. The anode current collection portion is coated with the anode active material layer, and at least a portion of the anode protrusion is not coated with the anode active material layer. The anode protrusion serves as an anode tab. The anode current collector can be made of copper, and the anode active material layer includes an anode active material, which can be carbon or silicon, etc. To ensure that a large current can pass through without melting, there are multiple cathode tabs stacked together, and there are multiple anode tabs stacked together. Furthermore, the electrode assembly can be a wound structure, but this disclosure is not limited to this.

[0114] "End cap 11 is welded to housing 12 from its outer periphery" indicates that end cap 11 and housing 12 are welded using a side welding method. This side welding method results in the outer surface of the weld 13 being located at the junction of the outer periphery of end cap 11 and housing 12. Side welding has lower assembly requirements and a simpler welding process. End cap 11 and housing 12 can be welded using, but is not limited to, laser welding. As shown in Figure 6, interfaces OP and PQ illustrate the interface between weld 13 and end cap 11. The interface between weld 13 and end cap 11 (interfaces OP and PQ) is the boundary area between weld 13 and end cap 11. In Figure 6, the interface between weld 13 and end cap 11 (interfaces OP and PQ) and the protruding end face 1141 of the first protrusion 114 are spaced along the thickness direction X, indicating that the boundary area between weld 13 and end cap 11 and the protruding end face 1141 are spaced along the thickness direction X of end cap 11.

[0115] End cap 11 refers to a component that covers the opening of housing 12 to isolate the internal environment of battery cell 20 from the external environment. In any case, the shape of end cap 11 can be adapted to the shape of housing 12 to fit it. Optionally, end cap 11 can be made of a material with a certain degree of hardness and strength, so that end cap 11 is not easily deformed under pressure or impact, enabling battery cell 20 to have higher structural strength and improved safety performance.

[0116] The end cap 11 may also be provided with a pressure relief mechanism 15 for releasing internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. The pressure relief mechanism 15 may be, but is not limited to, an explosion-proof valve. The end cap 11 can also be made of various materials, such as copper, iron, aluminum, aluminum alloy, steel, titanium alloy, and copper alloy, etc., and this disclosure does not impose any special limitations on these materials. In some embodiments of this disclosure, an insulating structure may also be provided on the inner side of the end cap 11. The insulating structure can be used to isolate the electrical connection components within the housing 12 from the end cap 11 to reduce the risk of short circuits. For example, the insulating structure may be made of plastic, rubber, etc.

[0117] At least a portion of the edge of the first surface 113 of the end cap 11 is formed with a first protrusion 114, indicating that the first protrusion 114 protrudes outward relative to the first surface 113. The first protrusion 114 may be formed on all four edges of the first surface 113, or it may be formed on only a portion of the edge.

[0118] The housing 12 is a component used to cooperate with the end cap 11 to form the internal environment of the battery cell 20, wherein the formed internal environment can accommodate the electrode assembly 2, electrolyte, and other components. The housing 12 and the end cap 11 are independent components. An opening is provided on the housing 12, and the end cap 11 closes the opening to form the internal environment of the battery cell 20. The housing 12 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 12 can be determined according to the specific shape and size of the electrode assembly 2. The material of the housing 12 can be various, such as copper, iron, aluminum, aluminum alloy, plastic, steel, titanium alloy, and copper alloy, etc., and this disclosure does not impose any special limitations on this.

[0119] In the embodiments of this disclosure, by providing a first protrusion 114 at the edge of the first surface 113 of the end cap 11, when welding from the outer periphery of the end cap 11, the distance between the protruding end face 1141 of the first protrusion 114 and the welding center is large, making it difficult for the weld to melt to the protruding end face 1141 of the first protrusion 114 during welding. Furthermore, the junction area between the weld 13 and the end cap 11 and the protruding end face 1141 are spaced apart in the thickness direction X of the end cap 11, that is, the weld width of the weld 13 does not exceed the outer surface of the end cap 11 (including the first surface 113 and the protruding end face 1141), thereby improving the reliability of the weld and thus improving the structural strength of the battery cell 20. Moreover, by providing the first protrusion 114 only at the edge of the end cap 11, the thickness of the remaining part of the end cap 11 is still relatively thin, which is beneficial to improving the volumetric energy density of the battery cell 20.

[0120] In some embodiments of this disclosure, as shown in FIG6, the minimum distance D1 between the junction area of ​​the weld 13 and the end cap 11 and the raised end face 1141 along the thickness direction X of the end cap 11 is in the range of 0.2mm to 2.5mm.

[0121] As shown in Figure 6, the closest position between the interface OP and interface PQ of the junction area between weld 13 and end cap 11 and the raised end face 1141 is position O. The distance D1 between position O and the raised end face 1141 represents the minimum distance between the junction area between weld 13 and end cap 11 and the raised end face 1141. For example, the minimum distance D1 between the junction area between weld 13 and end cap 11 and the raised end face 1141 can be, but is not limited to, 0.2mm, 0.4mm, 0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2.0mm, 2.2mm, 2.4mm, or 2.5mm.

[0122] In this way, by limiting the minimum distance D1 between the junction area of ​​weld 13 and end cap 11 and the raised end face 1141 to the range of 0.2mm to 2.5mm, the position of weld 13 is appropriate, so that it will not exceed the raised end face 1141, nor will it easily extend into the inner surface of end cap 11, thereby improving the reliability of welding and improving the structural strength of battery cell 20.

[0123] In some embodiments of this disclosure, a first protrusion 114 is formed on all four edges of the first surface 113.

[0124] Thus, the first protrusion 114 forms a ring around the first surface 113, which improves the structural strength of the end cap 11. Moreover, it ensures that the entire weld seam 13 does not exceed the protruding end face 1141 of the first protrusion 114, thereby improving the reliability of the weld and the structural strength of the battery cell 20.

[0125] In some embodiments of this disclosure, the surface of the end cap 11 facing the receiving cavity includes a second surface 111, and the junction area of ​​the weld 13 and the end cap 11 and the second surface 111 of the end cap 11 are spaced apart along the thickness direction X of the end cap 11.

[0126] As shown in Figure 6, interfaces OP and PQ are the interfaces between weld 13 and end cap 11. The interfaces between weld 13 and end cap 11 (interfaces OP and PQ) are the junction areas between weld 13 and end cap 11. The interfaces between weld 13 and end cap 11 (interfaces OP and PQ) in Figure 6 are spaced from the second surface 111 along the thickness direction X, indicating that the junction area between weld 13 and end cap 11 and the second surface 111 of end cap 11 are spaced from each other along the thickness direction X of end cap 11.

[0127] This ensures that the weld 13 does not extend beyond the second surface 111 of the end cap 11, improving the reliability of the weld. Furthermore, it prevents the weld 13 from extending into the receiving cavity of the outer casing 1, thus protecting the electrode assembly 2 within the receiving cavity and reducing the risk of short circuit in the battery cell 20 due to the electrode assembly 2 being punctured.

[0128] In some embodiments of this disclosure, along the thickness direction X of the end cap 11, the minimum distance D2 between the junction area of ​​the weld 13 and the end cap 11 and the second surface 111 of the end cap 11 is in the range of 0.25 mm to 2.5 mm.

[0129] As shown in Figure 6, the closest position of the interface area (interface OP and interface PQ) between the weld 13 and the end cap 11 to the second surface 111 is position Q. The distance D2 between position Q and the second surface 111 represents the minimum distance between the interface area of ​​the weld 13 and the end cap 11 and the second surface 111. For example, the minimum distance D2 between the interface area of ​​the weld 13 and the end cap 11 and the second surface 111 can be, but is not limited to, 0.25mm, 0.4mm, 0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2.0mm, 2.2mm, 2.4mm, or 2.5mm.

[0130] In this way, by limiting the minimum distance D1 between the junction area of ​​weld 13 and end cap 11 and the second surface 111 to the range of 0.25mm to 2.5mm, the position of weld 13 is appropriate, neither exceeding the protruding end face 1141 nor extending into the inner side of end cap 11 beyond the second surface 111 of end cap 11, thereby improving the reliability of welding, increasing the structural strength of battery cell 20, and reducing the risk of short circuit in battery cell 20.

[0131] In some embodiments of this disclosure, as shown in FIG6, the distance S1 between the second surface 111 and the first surface 113 of the end cap 11 is in the range of 0.4 mm to 2.5 mm.

[0132] For example, the distance S1 between the second surface 111 and the first surface 113 of the end cap 11 can be, but is not limited to, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, or 2.5mm.

[0133] The first protrusion 114 is designed so that it is not easy to melt to the protruding end face 1141 of the first protrusion 114 during welding. Therefore, the thickness of the end cover 11 can be reduced. For this purpose, the thickness of the end cover 11 is set between 0.4mm and 2.5mm, which will not affect the reliability of the welding, reduce the space occupied, and improve the volumetric energy density of the battery cell 20.

[0134] In some embodiments of this disclosure, as shown in FIG6, the distance S1 between the second surface 111 and the first surface 113 of the end cap 11 is in the range of 0.8 mm to 1 mm.

[0135] For example, the distance S1 between the second surface 111 and the first surface 113 of the end cap 11 can be, but is not limited to, 0.8mm, 0.81mm, 0.82mm, 0.83mm, 0.84mm, 0.85mm, 0.86mm, 0.87mm, 0.88mm, 0.89mm, 0.9mm, 0.91mm, 0.92mm, 0.93mm, 0.94mm, 0.95mm, 0.96mm, 0.97mm, 0.98mm, 0.99mm, or 1mm.

[0136] The first protrusion 114 is designed so that it is not easy to melt to the protruding end face 1141 of the first protrusion 114 during welding. Therefore, the thickness of the end cover 11 can be reduced. For this purpose, the thickness of the end cover 11 is set between 0.8mm and 1mm, which will not affect the reliability of the welding, reduce the space occupied, and improve the volumetric energy density of the battery cell 20.

[0137] In some embodiments of this disclosure, as shown in Figures 6 to 9, at least a portion of the edge of the second surface 111 of the end cap 11 is formed with a first recess 112, and one end of the housing 12 with an opening is engaged with the first recess 112 and welded to the first recess 112.

[0138] At least a portion of the edge of the second surface 111 is formed with a first recess 112, indicating that the first recess 112 is recessed relative to the second surface 111, and the first recess 112 forms an opening on the outer surface of the end cap 11. The first recess 112 may be formed on all four edges of the second surface 111, or it may be formed on only a portion of the edge.

[0139] The first recess 112 of the end cap 11 engages with the end of the housing 12, which increases the contact area between the end cap 11 and the housing 12, thereby improving the welding reliability of the end cap 11 and the housing 12. Moreover, since the end of the housing 12 is engaged with the first recess 112, the welding center of the end cap 11 and the housing 12 is offset from the side of the second surface 111 toward the first surface 113, so that the weld 13 formed by the welding is located between the second surface 111 and the raised end face 1141, thereby improving the welding reliability, improving the structural strength of the battery cell 20, and reducing the risk of short circuit in the battery cell 20.

[0140] In some embodiments of this disclosure, a first recess 112 is formed on all four edges of the second surface 111.

[0141] Thus, the first recess 112 forms a ring around the second surface 111, which engages with the ring edge of the housing 12, improving the reliability of the connection between the end cap 11 and the housing 12.

[0142] In some embodiments of this disclosure, as shown in FIG6, an arcuate transition surface 115 is formed between the second surface 111 of the end cap 11 and the weld 13. Along the thickness direction of the end cap 11, there is a gap between the junction area of ​​the weld 13 and the end cap 11 and the arcuate transition surface 115.

[0143] As shown in Figure 6, there is a gap between the junction area (interface OP and interface PQ) between the weld 13 and the end cap 11 and the arc transition surface 115 of the end cap 11, so that the weld 13 avoids the arc transition surface 115 which is prone to collapse. This prevents the weld from being welded to the collapse area during the welding process, thus improving the reliability of the weld and further improving the structural strength of the battery cell 20.

[0144] In some embodiments of this disclosure, as shown in FIG6, an arcuate transition surface 115 is formed between the second surface 111 of the end cap 11 and the inner surface of the first recess 112. Along the thickness direction X of the end cap 11, there is a gap between the junction area of ​​the weld 13 and the end cap 11 and the arcuate transition surface 115.

[0145] As shown in Figure 6, there is a gap between the junction area (interface OP and interface PQ) of weld 13 and end cap 11 and the arc-shaped transition surface 115 of end cap 11, so that the shell 12 is welded to the flat inner surface of the first recess 112, avoiding the arc-shaped transition surface 115 which is prone to collapse. This prevents the weld from being welded to the collapse area during the welding process, thus improving the reliability of the weld and further improving the structural strength of the battery cell 20.

[0146] In some embodiments of this disclosure, as shown in FIG9, the size S4 of the arcuate transition surface 115 along the thickness direction X of the end cap 11 is in the range of 0.05mm to 0.025mm.

[0147] For example, as shown in FIG9, the dimension S4 of the arcuate transition surface 115 along the thickness direction X can be, but is not limited to, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.10mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.20mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm or 0.25mm.

[0148] Thus, the size S4 of the arc-shaped transition surface 115 is smaller, and correspondingly, the area of ​​the flat surface in the first recess 112 is larger, which increases the area of ​​the first recess 112 and the housing 12 to fit and abut, thereby further improving the welding reliability of the end cap 11 and the housing 12.

[0149] In some embodiments of this disclosure, the first recess 112 and the first protrusion 114 of the end cap 11 are formed by stamping from one side of the second surface 111.

[0150] During the process of stamping the first recess 112 from one side of the raw material sheet used to manufacture the end cap 11, since the end cap mold has a recessed structure on the other side facing the raw material sheet that allows material to avoid it, some material is squeezed into the recessed structure on the end cap mold during the process of the raw material sheet being stamped inward, which reduces the stamping pressure generated on the end cap mold. In this way, the impact force on the end cap mold when stamping to form the end cap 11 can be reduced, the service life of the end cap mold can be extended, and thus the manufacturing cost of the battery cell 20 can be reduced.

[0151] In addition, during the process of the raw material sheet being stamped and recessed inward, some material is squeezed to avoid the recessed structure on the end cap mold, which reduces the stamping pressure generated by the end cap mold. Therefore, the reaction force of the end cap mold on the raw material sheet is also reduced accordingly, which helps to reduce the probability of the inner surface of the first recess 112 being deformed due to the reaction force of the end cap mold. This helps to control the radius of the arc transition surface 115 within a small range, and further helps to improve the reliability of the engagement between the inner surface of the first recess 112 and the end of the shell 12.

[0152] In some embodiments of this disclosure, the dimension S2 of the first recess 112 along the thickness direction X of the end cap 11 is in the range of 0.15 mm to 1.5 mm.

[0153] As shown in Figure 9, the dimension S2 of the first recess 112 along the thickness direction X of the end cap 11 is the maximum distance between the surface F of the first recess 112 facing the housing 12 and the second surface 111 of the end cap 11 along the thickness direction X of the end cap 11.

[0154] For example, the dimension S2 of the first recess 112 along the thickness direction X of the end cap 11 can be, but is not limited to, 0.15mm, 0.20mm, 0.25mm, 0.30mm, 0.35mm, 0.40mm, 0.45mm, 0.50mm, 0.55mm, 0.60mm, 0.65mm, 0.70mm, 0.75mm, 0.80mm, 0.85mm, 0.90mm, 0.95mm, 1.00mm, 1.05mm, 1.10mm, 1.15mm, 1.20mm, 1.25mm, 1.30mm, 1.35mm, 1.40mm, 1.45mm, or 1.50mm.

[0155] In this way, the dimension S2 of the first recess 112 along the thickness direction X of the end cap 11 is limited to the range of 0.15mm to 1.5mm, so that the first recess 112 and the housing 12 fit together more securely and do not take up too much space.

[0156] In some embodiments of this disclosure, the dimension S2 of the first recess 112 along the thickness direction X of the end cap 11 is in the range of 0.35 mm to 0.75 mm.

[0157] For example, the dimension S2 of the first recess 112 along the thickness direction X of the end cap 11 can be, but is not limited to, 0.35mm, 0.36mm, 0.37mm, 0.38mm, 0.39mm, 0.4mm, 0.41mm, 0.42mm, 0.43mm, 0.44mm, 0.45mm, 0.46mm, 0.47mm, 0.48mm, 0.49mm, 0.5mm, 0.51mm, or 0.52mm. , 0.53mm, 0.54mm, 0.55mm, 0.56mm, 0.57mm, 0.58mm, 0.59mm, 0.6mm, 0.61mm, 0.62mm, 0.63mm, 0.6 4mm, 0.65mm, 0.66mm, 0.67mm, 0.68mm, 0.69mm, 0.7mm, 0.71mm, 0.72mm, 0.73mm, 0.74mm, 0.75mm.

[0158] In this way, the dimension S2 of the first recess 112 along the thickness direction X of the end cap 11 is limited to the range of 0.35mm to 0.75mm, so that the first recess 112 and the housing 12 fit together more securely and do not take up too much space.

[0159] In some embodiments of this disclosure, as shown in FIG9, along the thickness direction X of the end cap 11, the size S3 of the first protrusion 114 is smaller than the size S2 of the first recess 112. That is, the size of the first protrusion 114 extending beyond the first surface 113 along the thickness direction X of the end cap 11 is smaller than the distance between the surface F of the first recess 112 facing the bottom plate 121 and the second surface 111.

[0160] For example, along the thickness direction X of the end cap 11, the size S3 of the first protrusion 114 is 0.2 mm, and the size S2 of the first recess 112 is 0.4 mm.

[0161] In this way, the impact force on the end cap mold is reduced, the service life of the end cap mold is extended, and the dimensional relationship is limited as described above, which suppresses the increase in the space occupied in the thickness direction X due to the setting of the first protrusion 114.

[0162] In some embodiments of this disclosure, as shown in Figures 3 to 5, the first protrusion 114 and the first surface 113 of the end cap 11 define a recessed area, and the battery cell 20 further includes an electrode post 14 disposed in the recessed area of ​​the end cap 11 and connected to the electrode assembly 2.

[0163] The electrode post 14 is electrically connected to the tab 21 of the electrode assembly 2. The electrode post 14 can be directly connected to the tab 21, or indirectly connected to the tab 21 through the adapter piece 16. The electrode post 14 is used to introduce or export current.

[0164] The electrode post 14 is located in the recessed area of ​​the end cover 11, which reduces the space occupied by the entire battery cell 20 in the thickness direction X of the end cover 11, thereby improving the volumetric energy density of the battery cell 20.

[0165] In some embodiments of this disclosure, as shown in Figures 4 and 7, the outer surface of the housing 1 is covered with a protective film 3, which covers at least a portion of the first protrusion 114.

[0166] The protective film 3 is a film material used to cover the outside of the outer shell 1 to protect the outer shell 1. The protective film 3 can be, but is not limited to, a blue film. The protective film 3 can cover part of the outer surface of the first protrusion 114. For example, the protective film 3 is bent to cover the protruding end face 1141 of the first protrusion 114, but does not cover the surface of the first protrusion 114 that is connected to the first surface 113. The protective film 3 can also cover the entire outer surface of the first protrusion 114. For example, as shown in FIG7, the protective film 3 extends from the outer periphery of the shell 12 to the end cap 11 and is bent to fully cover the first protrusion 114.

[0167] The protective film 3 is provided to insulate and protect the outer casing 1, thereby extending the service life of the battery cell 20.

[0168] In some embodiments of this disclosure, the housing 12 includes a base plate 121 and a side plate 122 surrounding the base plate 121. An end cap 11 is connected to the side plate 122 and is opposite to the base plate 121 along the thickness direction X of the end cap 11. The weld 13 protrudes from the outer surface of the side plate 122 in a direction perpendicular to the outer surface of the side plate 122 by a dimension H1 smaller than the thickness of the protective film 3.

[0169] The side plate 122 is a plate surrounding the base plate 121. It can be an arc-shaped plate surrounding the central axis, a structure composed of four straight plates connected end to end, or a structure composed of other numbers of straight plates connected end to end. The shape of the end cap 11 is adapted to the shape formed by the side plate 122.

[0170] During the assembly process of the battery cell 20, the electrode assembly 2 is first placed inside the housing 12, and then the end cap 11 is sealed at the opening of the housing 12, so that the first recess 112 of the end cap 11 and the end of the side plate 122 away from the bottom plate 121 are engaged, and then the end cap 11 and the side plate 122 are welded together.

[0171] For example, as shown in FIG6, the weld 13 protrudes from the outer surface of the side plate 122 in a direction perpendicular to the outer surface of the side plate 122 by a dimension H1 from the outer surface of the side plate 122 to the top of the weld 13, and the dimension H1 is less than the thickness of the protective film 3.

[0172] Thus, the dimension of the weld 13 extending beyond the side plate 122 is less than the thickness of the protective film 3, making it less likely for the protective film 3 covering the outer periphery of the side plate 122 to be punctured by the weld 13, thereby improving the protective effect of the protective film 3.

[0173] In some embodiments of this disclosure, as shown in FIG6, the weld penetration depth H2 of weld 13 is not less than the thickness of side plate 122; and / or, the weld width W of weld 13 is not less than 0.3 mm.

[0174] The penetration depth of weld 13 refers to the depth to which the molten metal of the welding wire or electrode penetrates the base material during the welding process. Penetration depth is a key indicator for measuring weld strength. Generally, weld strength is directly proportional to penetration depth. As shown in Figure 7, the penetration depth H2 of weld 13 is the dimension of the deepest end of weld 13 located inside end cap 11 and the outer surface of side plate 122 along a direction perpendicular to the outer surface of side plate 122.

[0175] The weld width W of weld 13 refers to the transverse width of the molten metal from the welding wire or electrode during the welding process. Weld width W is an important indicator for measuring welding quality. Generally, the larger the weld width W, the stronger the bond between welds and the higher the strength. As shown in Figure 6, the weld width W of weld 13 is the dimension of weld 13 projected onto the thickness direction X of end cap 11 along the orthographic projection of weld 13 in the direction perpendicular to side plate 122.

[0176] Thus, by setting the weld penetration depth H2 of weld 13 to be no less than the thickness of side plate 122, the welding strength of side plate 122 and end cap 11 is improved, and the reliability of the connection is enhanced. Setting the weld width W of weld 13 to be no less than 0.3 mm improves the welding quality, thereby further enhancing the reliability of the connection between side plate 122 and end cap 11.

[0177] In some embodiments of this disclosure, as shown in FIG3, the side plate 122 includes two first shell plates 1221 and two second shell plates 1222. The two first shell plates 1221 and the two second shell plates 1222 are both connected to the bottom plate 121 and the end cap 11. The dimension of the end cap 11 along the length direction Y is greater than the dimension along the width direction Z. The two first shell plates 1221 are arranged opposite each other along the length direction Y of the end cap 11, and the two second shell plates 1222 are arranged opposite each other along the width direction Z of the end cap 11.

[0178] Thus, the outer shell 1 forms a cubic shell, making the battery cell 20 a square-shell battery, and the surface of the second shell plate 1222 is the surface with the largest area of ​​the outer shell 1.

[0179] In some embodiments of this disclosure, as shown in FIG4, the battery cell 20 further includes an adapter piece 16, one end of which is connected to the terminal post 14, and the other end is connected to the tab 21 of the electrode assembly 2. This achieves an electrical connection between the terminal post 14 and the tab 21.

[0180] In some embodiments of this disclosure, the outer surface of the end cap 11 of the battery cell 20 is covered with an end cap patch 17.

[0181] In some embodiments of this disclosure, the end cap 11 is made of at least one of steel, titanium alloy, and copper alloy; the housing 12 is made of at least one of steel, titanium alloy, and copper alloy.

[0182] The end cap 11 and housing 12 made of the above-mentioned materials have high structural strength, which is beneficial to improving the structural strength of the battery cell 20. In addition, the end cap 11 and housing 12 made of the above-mentioned materials require high welding power during welding, which can easily cause the weld 13 to extend to the outer surface of the end cap 11. Therefore, in this embodiment of the present disclosure, by providing a first protrusion 114 at the edge of the first surface 113 of the end cap 11, when welding from the outer periphery of the end cap 11, the distance between the protruding end face 1141 of the first protrusion 114 and the welding center is large, making it less likely to melt to the protruding end face 1141 of the first protrusion 114 during welding. Furthermore, the junction area between the weld 13 and the end cap 11 and the protruding end face 1141 are spaced apart in the thickness direction X of the end cap 11. That is, the weld width of the weld 13 does not exceed the outer surface of the end cap 11 (including the first surface 113 and the protruding end face 1141), thereby improving the reliability of the weld and thus improving the structural strength of the battery cell 20.

[0183] In some embodiments of this disclosure, the wall thickness of the housing 12 is in the range of 0.05 mm to 5 mm.

[0184] The housing 12 includes a base plate 121 and a side plate 122 surrounding the base plate 121. The thickness of both the base plate 121 and the side plate 122 is in the range of 0.05 mm to 5 mm.

[0185] For example, the wall thickness of the housing 12 can be, but is not limited to, 0.05mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, etc. m, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3 .7mm, 3.8mm, 3.9mm, 4mm, 4.1mm, 4.2mm, 4.3mm, 4.4mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm, 5mm.

[0186] Thus, by limiting the wall thickness of the casing 12 to the range of 0.05mm to 5mm, the casing 12 becomes relatively thin, reducing space occupation and increasing the volumetric energy density of the battery cell 20. Furthermore, when the material of the casing 12 includes at least one of steel, titanium alloy, and copper alloy, the structural strength of the casing 12 is relatively high, resulting in high structural strength and high volumetric energy density of the battery cell 20.

[0187] In some embodiments of this disclosure, the wall thickness of the housing 12 is in the range of 0.1 mm to 3 mm.

[0188] For example, the wall thickness of the housing 12 can be, but is not limited to, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, and 3mm.

[0189] Thus, by limiting the wall thickness of the casing 12 to the range of 0.1mm to 3mm, the casing 12 becomes relatively thin, reducing space occupation and increasing the volumetric energy density of the battery cell 20. Furthermore, when the material of the casing 12 includes at least one of steel, titanium alloy, and copper alloy, the structural strength of the casing 12 is relatively high, resulting in high structural strength and high volumetric energy density of the battery cell 20.

[0190] In some embodiments of this disclosure, a second recess is formed on all four edges of the surface of the base plate 121 facing the receiving cavity, one end of the side plate 122 is engaged with the second recess, the second recess of the base plate 121 and the side plate 122 are welded together, and a second protrusion is formed on all four edges of the surface of the base plate 121 facing away from the receiving cavity. The second recess and the second protrusion of the base plate 121 are formed by stamping from one side of the second recess.

[0191] The second recess of the base plate 121 engages with the end of the side plate 122, which increases the contact area between the base plate 121 and the side plate 122, thereby improving the connection reliability between the base plate 121 and the side plate 122. A second protrusion is formed opposite the second recess of the base plate 121, which helps to improve the structural strength of the base plate 121, thereby helping to further improve the structural strength of the battery cell 20. Furthermore, the base plate 121 has a second protrusion on the side opposite to the second recess. The base plate mold used for stamping the base plate 121 has a recessed structure that matches the shape of the second protrusion. Thus, during the stamping process of forming the second recess from one side of the raw material sheet used to manufacture the base plate 121, because the base plate mold has a recessed structure on the side facing the raw material sheet, some material is squeezed into the recessed structure on the base plate mold during the stamping process, which reduces the stamping pressure on the base plate mold. This reduces the impact force on the base plate mold when stamping the base plate 121, extends the service life of the base plate mold, and thus helps to reduce the manufacturing cost of the battery cell 20. The base plate 121 and the side plate 122 are connected by welding, which is simple to operate and has a high connection strength.

[0192] A second aspect of this disclosure provides a battery device including at least one battery cell 20 provided in the first aspect.

[0193] Since the battery device includes the battery cell 20 provided in the first aspect, and the battery cell 20 has high structural strength and high volumetric energy density, the battery device has both high structural strength and high volumetric energy density.

[0194] In some embodiments, the battery device may be a battery pack 100, which includes a battery case 10 and one or more battery cells 20, with the battery cells 20 housed in the battery case 10.

[0195] In some embodiments, the battery device may be an energy storage device, which may include an energy storage container, an energy storage cabinet, etc.

[0196] A third aspect of this disclosure provides an electrical device comprising a battery cell 20 provided by a first aspect or a battery device provided by a second aspect for providing electrical energy.

[0197] Since the battery device includes the battery cell 20 provided by the first aspect or the battery device provided by the second aspect, and the battery cell 20 and the battery device have high structural strength and high volumetric energy density, the power device has high structural strength and high volumetric energy density.

[0198] Figure 10 is a first flowchart of a battery cell manufacturing method provided in some embodiments of the present disclosure; Figure 11 is a second flowchart of a battery cell manufacturing method provided in some embodiments of the present disclosure.

[0199] As shown in Figure 10, the fourth aspect of this disclosure provides a method for manufacturing a battery cell, comprising:

[0200] S100 provides housing, end caps and electrode assembly;

[0201] S200, install the electrode assembly into the housing;

[0202] S300, the end cap is welded to the housing from the outer periphery of the end cap so that the end cap closes the opening of the housing;

[0203] The surface of the end cap 11 facing away from the receiving cavity includes a first surface 113, at least a portion of the edge of the first surface 113 is formed with a first protrusion 114, the surface of the first protrusion 114 facing away from the receiving cavity is a raised end face 1141, and the junction area between the weld 13 and the end cap 11 and the raised end face 1141 are spaced apart in the thickness direction X of the end cap 11.

[0204] In the embodiments of this disclosure, by providing a first protrusion 114 at the edge of the first surface 113 of the end cap 11, when welding from the outer periphery of the end cap 11, the distance between the protruding end face 1141 of the first protrusion 114 and the welding center is large, making it difficult for the weld to melt to the protruding end face 1141 of the first protrusion 114 during welding. Furthermore, the junction area between the weld 13 and the end cap 11 and the protruding end face 1141 are spaced apart in the thickness direction X of the end cap 11, that is, the weld width of the weld 13 does not exceed the outer surface of the end cap 11 (including the first surface 113 and the protruding end face 1141), thereby improving the reliability of the weld and thus improving the structural strength of the battery cell 20. Moreover, by providing the first protrusion 114 only at the edge of the end cap 11, the thickness of the remaining part of the end cap 11 is still relatively thin, which is beneficial to improving the volumetric energy density of the battery cell 20.

[0205] In some embodiments of this disclosure, as shown in FIG11, the battery cell manufacturing method further includes, before providing the housing, end cap, and electrode assembly:

[0206] S001, providing raw material boards;

[0207] S002, Place the raw material sheet into the end cap mold;

[0208] S003, the raw material sheet is stamped from the first side to form the first structure;

[0209] S004, the first structure is cut to form an end cap;

[0210] The end cap 11 has a second surface 111 on the surface facing the first side, and at least a portion of the edge of the second surface 111 has a first recess 112 formed by a stamping operation. The end cap 11 has a first surface 113 on the surface away from the first side, and at least a portion of the edge of the first surface 113 has a first protrusion 114 formed by a stamping operation.

[0211] During the process of stamping the first recess 112 from one side of the raw material sheet used to manufacture the end cap 11, since the end cap mold has a recessed structure on the other side facing the raw material sheet that allows material to avoid it, some material is squeezed into the recessed structure on the end cap mold during the process of the raw material sheet being stamped inward, which reduces the stamping pressure generated on the end cap mold. In this way, the impact force on the end cap mold when stamping to form the end cap 11 can be reduced, the service life of the end cap mold can be extended, and thus the manufacturing cost of the battery cell 20 can be reduced. In addition, during the process of the raw material sheet being stamped and recessed inward, some material is squeezed to avoid the recessed structure on the end cap mold, which reduces the stamping pressure generated by the end cap mold. Therefore, the reaction force of the end cap mold on the raw material sheet is also reduced accordingly, which helps to reduce the probability of the inner surface of the first recess 112 being deformed due to the reaction force of the end cap mold. This helps to control the radius of the arc transition surface 115 within a small range, and further helps to improve the reliability of the engagement between the inner surface of the first recess 112 and the end of the shell 12.

[0212] The following describes specific examples of some embodiments of this disclosure with reference to the accompanying drawings.

[0213] As a specific example, a battery cell 20 is provided, which includes a steel cover plate (end cap 11) and a steel shell (shell 12). The steel cover plate closes the opening of the steel shell, forming a receiving cavity for accommodating an electrode assembly (electrode assembly 2). A protrusion (first protrusion 114) is formed on the opposite side of the T-shaped step (first recess 112) of the steel cover plate. The protrusion is formed along with the material during the stamping process of forming the T-shaped step. The steel cover plate and the steel shell are welded together by side welding. Because the weld (weld 13) formed by the welding and the steel cover plate do not exceed the raised end face (raised end face 1141) of the steel cover plate along the thickness direction (thickness direction X) of the steel cover plate, nor do they exceed the surface of the steel cover plate facing the receiving cavity (second surface 111), the reliability of the welding is improved, the structural strength of the battery cell 20 is improved, and the risk of short circuit of the battery cell 20 is reduced. Moreover, the protrusion is only set at the edge of the steel cover plate, and the thickness of the rest of the steel cover plate is still relatively thin, which is beneficial to improving the volumetric energy density of the battery cell 20.

[0214] The above embodiments are merely illustrative of the technical solutions of this disclosure and are not intended to limit it. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this disclosure, and all should be covered within the scope of this disclosure. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way.

Claims

1. A battery cell comprising: a housing including a case and a cap, the case having an opening, the cap closing the opening, the case and the cap enclosing a receiving cavity, the cap being welded to the case from an outer peripheral side of the cap to form a weld; an electrode assembly received in the receiving cavity; wherein a surface of the cap facing away from the receiving cavity includes a first surface, at least a portion of an edge of the first surface is formed with a first protrusion, a surface of the first protrusion facing away from the receiving cavity is a convex end surface, and a boundary region of the weld with the cap and the convex end surface have a spacing in a thickness direction of the cap.

2. The battery cell according to claim 1, wherein: a material of the cap includes at least one of steel, a titanium alloy, and a copper alloy; and / or a material of the case includes at least one of steel, a titanium alloy, and a copper alloy.

3. The battery cell of claim 1 or 2, wherein, a minimum spacing between the boundary region of the weld with the cap and the convex end surface in the thickness direction of the cap is in a range of 0.2 mm to 2.5 mm.

4. The battery cell of any one of claims 1 to 3, wherein, a surface of the cap facing the receiving cavity includes a second surface, the boundary region of the weld with the cap and the second surface of the cap have a spacing in the thickness direction of the cap.

5. The battery cell of claim 4, wherein, a minimum spacing between the boundary region of the weld with the cap and the second surface of the cap in the thickness direction of the cap is in a range of 0.25 mm to 2.5 mm.

6. The battery cell of claim 4 or 5, wherein, a spacing of the second surface of the cap to the first surface is in a range of 0.4 mm to 2.5 mm.

7. The battery cell of claim 4 or 5, wherein, a spacing of the second surface of the cap to the first surface is in a range of 0.8 mm to 1 mm.

8. The battery cell of any one of claims 4-7, wherein, the second surface of the cap and the weld form an arc-shaped transition surface, the boundary region of the weld with the cap and the arc-shaped transition surface have a spacing in the thickness direction of the cap.

9. The battery cell of claim 8, wherein, a size of the arc-shaped transition surface in the thickness direction of the cap is in a range of 0.05 mm to 0.025 mm.

10. The battery cell of any one of claims 4-9, wherein, at least a portion of an edge of the second surface of the cap is formed with a first recess, an end portion of the case provided with the opening is engaged with the first recess and is welded to the first recess.

11. The battery cell of claim 10, wherein, the first recess and the first protrusion of the cap are formed by press working from one side of the second surface.

12. The battery cell of claim 10 or 11, wherein, a size of the first recess in the thickness direction of the cap is in a range of 0.15 mm to 1.5 mm.

13. The battery cell of any one of claims 10-12, wherein, a size of the first recess in the thickness direction of the cap is in a range of 0.35 mm to 0.75 mm.

14. The battery cell of any one of claims 1-13, wherein, the first protrusion of the cap and the first surface define a recessed region, the battery cell further includes a post provided in the recessed region of the cap and connected to the electrode assembly.

15. The battery cell of any one of claims 1-14, wherein, an outer surface of the housing is covered with a protective film, the protective film covering at least a portion of the first protrusion.

16. The battery cell of claim 15, wherein, the case includes a bottom plate and a side plate surrounding the bottom plate, the cap is connected to the side plate and is opposite to the bottom plate in the thickness direction of the cap, The weld protrudes the outer surface of the side plate in a direction perpendicular to the outer surface of the side plate by a dimension smaller than the thickness of the protective film.

17. The battery cell according to claim 16, wherein, a depth of penetration of the weld is not less than the thickness of the side plate; and / or a width of penetration of the weld is not less than 0.3 mm.

18. The battery cell of any one of claims 1-17, wherein, The wall thickness of the case is in a range of 0.05 mm to 5 mm.

19. The battery cell of any one of claims 1-17, wherein, The wall thickness of the case is in a range of 0.1 mm to 3 mm.

20. A battery device comprising: at least one battery cell according to any one of claims 1 to 19.

21. An electric device comprising a battery cell according to any one of claims 1 to 19 or a battery device according to claim 20 for supplying electric power.

22. A battery cell manufacturing method comprising: providing a case, a lid, and an electrode assembly; mounting the electrode assembly in the case; welding the lid to the case from the outer peripheral side of the lid such that the lid closes the opening of the case; wherein the welding of the lid to the case forms a weld, and the lid and the case enclose a receiving cavity, a surface of the lid facing away from the receiving cavity includes a first surface, at least a portion of the edge of the first surface is formed with a first protruding portion, a surface of the first protruding portion facing away from the receiving cavity is a convex end surface, and the interface region of the weld with the lid and the convex end surface are spaced apart in the thickness direction of the lid.

23. The battery cell manufacturing method of claim 22, wherein, Before the providing of the case, the lid, and the electrode assembly, the method further comprises: providing a raw plate material; placing the raw plate material in a lid mold; performing a press work on the raw plate material from a first side of the raw plate material to form a first structure; cutting the first structure to form a lid; wherein a surface of the lid facing the first side includes a second surface, at least a portion of the edge of the second surface has a first recess portion formed by the press work, and a surface of the lid facing away from the first side includes the first surface, at least a portion of the edge of the first surface has the first protruding portion formed by the press work.

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