Battery cell, battery and electrical device

Abstract

Battery cell, exhibiting: an electrode assembly that has an electrode tab; a housing designed to accommodate the electrode assembly; and a current collector component that is housed in the casing and connected to the electrode tab; wherein the current collector component is welded to the inside of the housing to form a first weld section, wherein the weld penetration depth of the first weld section formed on the housing is less than the thickness of the housing.

Description

TECHNICAL AREA

[0001] The present application relates to the field of battery technology, in particular to a battery cell, a battery and an electrical device. BACKGROUND TECHNOLOGY

[0002] Energy saving and emission reduction are crucial for the sustainable development of the automotive industry. Electric vehicles have become an important component of this sustainable development due to their energy-saving and environmentally friendly advantages. Battery technology is another crucial factor for the further development of electric vehicles.

[0003] In certain scenarios, batteries can use current collector components to draw electrical current for transmission to electrical devices. These current collector components are attached to the battery by welding. This welding process can compromise the battery's seal and lead to electrolyte leakage. CONTENTS OF THE INVENTION

[0004] The present application aims to solve at least one of the technical problems existing in the existing art. Accordingly, one objective of the present application is to provide a battery cell, a battery, and an electrical device that solves the problem of electrolyte leakage in batteries.

[0005] In the first aspect, the embodiment of the present application provides a battery cell comprising an electrode assembly, a housing, and a current collector component, wherein the electrode assembly has an electrode tab, the housing is used to receive the electrode assembly, and the current collector component is housed in the housing and connected to the electrode tab. The current collector component is welded to the inside of the housing to form a first weld section, wherein the weld penetration depth of the first weld section formed on the housing is less than the thickness of the housing.

[0006] In the technical solution of this embodiment of the present application, the current collector component is welded to the inside of the housing by a structure of the battery cell to form a first weld section, wherein the weld penetration depth of the first weld section on the housing is less than the thickness of the housing. Thus, the housing is not penetrated during welding, and the first weld section cannot penetrate the housing either. Even if a crack forms at the weld point, namely at the first weld section, between the current collector component and the housing, the electrolyte inside the battery cell cannot escape through the crack to the outside of the housing, thereby effectively reducing the risk of electrolyte leakage.

[0007] In some embodiments, the housing has an opening, with the electrode tab located at the end of the electrode assembly closest to the opening. This positions the electrode tab, which is intended for connection with the current collector component, close to the opening on the electrode assembly. This facilitates the electrical connection between the current collector component and the electrode tab during battery cell assembly, resulting in convenient and efficient assembly.

[0008] In some embodiments, the inside of the housing comprises a first surface and a second surface, wherein the first surface is located opposite the electrode assembly, and the second surface is located on a side of the first surface that approaches the opening of the housing. The orthogonal projection of the first surface along the axial direction of the electrode assembly overlaps with the orthogonal projection of the second surface along the axial direction of the electrode assembly, and the first weld section is formed on the second surface. This design ensures that the current collector component can be welded to the inside of the housing without requiring structural modifications to the housing itself, thereby reducing costs.

[0009] In some embodiments, the current collector component comprises a first connection section and a second connection section associated therewith, wherein the first connection section is connected to the electrode tab, the second connection section engages with the inside of the housing, and the second connection section is welded to the inside of the housing to form at least one first weld section. This design ensures that the current collector component can be welded to the inside of the housing by configuring the second connection section of the current collector component to engage with the inside of the housing. Consequently, no structural modifications to the housing are required.

[0010] In some embodiments, the second connecting section is arranged at the outer edge of the first connecting section and is located on one side of the plane in which the first connecting section lies. Thus, the second connecting section projects beyond the first connecting section, which facilitates its adaptation to the inside of the housing. This arrangement simplifies welding the second connecting section to the inside of the housing.

[0011] In some embodiments, at least a portion of the outer surface of the second connection section rests against the inner surface of the housing, the outer surface of the second connection section being a surface that feeds the inner surface of the housing. Consequently, the configuration in which at least a portion of the outer surface of the second connection section rests against the inner surface of the housing facilitates the welding connection between the second connection section and the inner surface of the housing.

[0012] In some embodiments, the outside of the second connection section lies completely against the inside of the housing, with the entire outside of the second connection section firmly in contact with the inside of the housing, thereby further improving the stability of the welded connection between the second connection section and the inside of the housing.

[0013] In some embodiments, the first connecting section is a flat plate structure, wherein the outer surface of the second connecting section has a first projection on the plane in which the first connecting section lies, the first projection overlapping the outer surface of the first connecting section, the outer surface of the first connecting section being a surface facing the inside of the housing. In this embodiment, both the outer surface of the second connecting section and the outer surface of the first connecting section can be welded to the inside of the housing, thereby improving the stability of the weld joint on the inside of the housing of the current collector component.

[0014] In some embodiments, the first weld section does not pass through the second connection section along the axial direction of the electrode assembly. That is, when the laser beam is projected onto the second connection section and the housing along a direction parallel to the axial direction of the electrode assembly to form the first weld section, the laser beam does not pass through the second connection section. This prevents the laser beam from passing through the current collector component and being projected onto the electrode assembly, thus avoiding damage to the electrode assembly.

[0015] In some embodiments, the second connecting section comprises a contact section and a guide section, wherein the contact section engages with the inside of the housing and at least one section of the contact section is welded to the inside of the housing, wherein one end of the guide section is connected to the contact section, the other end of the guide section is connected to the first connecting section, wherein the distance between the guide section and the inside of the housing gradually increases from one end to the other end of the guide section.

[0016] In the above-mentioned technical solution, the guide section can fulfill a guiding function when the current collector component is installed in the housing, in order to facilitate the installation of the current collector component and thereby achieve high assembly efficiency.

[0017] In some embodiments, the first weld segment does not pass through the contact segment along the axial direction of the electrode assembly. When the laser beam is projected onto the contact segment and the housing along a direction parallel to the axial direction of the electrode assembly to form the first weld segment, the laser beam does not pass through the contact segment. This prevents the laser beam from passing through the current collector component and being projected onto the electrode assembly, thus avoiding damage to the electrode assembly.

[0018] In some embodiments, the second connecting section is firmly connected to the first connecting section via a connecting piece, or the second connecting section and the first connecting section are formed as one manufactured part through an integral forming process.

[0019] In the aforementioned technical solution, on the one hand, the assembly process for the first connection section and the second connection section is eliminated, which contributes to improving the assembly efficiency of the battery cell; on the other hand, the structural strength of the current collector component can be effectively improved without increasing costs if the first connection section and the second connection section are formed as one manufactured part through an integral forming process.

[0020] In some embodiments, the current collector component comprises only a second connection section, wherein the second connection section is an annular structure extending circumferentially around the inside of the housing. This design allows the second connection section to fit tightly around the entire circumference of the inside of the housing for the welded joint, thereby improving the connection stability.

[0021] In some embodiments, the second connecting section is welded to the inside of the housing to form multiple first weld sections, the multiple first weld sections being spaced apart from each other along the circumferential direction of the inside of the housing. In this example, multiple first weld sections between the second connecting section and the housing are evenly distributed to improve the reliability of the connection between the second connecting section and the housing.

[0022] In some embodiments, at least two of the multiple first weld sections are arranged symmetrically along the central axis of the housing. This configuration ensures that at least two of the multiple first weld sections are distributed and symmetrically arranged along the central axis of the housing, thereby improving the reliability of the connection between the current collector component and the housing.

[0023] In some embodiments, any two adjacent first weld sections are spaced at equal angular intervals along the circumferential direction of the inside of the housing. This dispersed arrangement of all first weld sections prevents interference between them. Furthermore, the force of gravity exerted by the electrode assembly on the current collector component, combined with the current collector component's own weight, acts evenly on several first weld sections. This reduces the probability of weld cracking at the first weld section between the second connection section and the housing due to uneven stress distribution, thereby further improving the reliability of the connection between the current collector component and the housing.

[0024] In some embodiments, the second connection section is welded to the inside of the housing to form a first weld section. This first weld section is an annular structure extending along the circumference of the inside of the housing, with the second connection section sealingly connected to the housing. Consequently, the second connection section is welded to the entire circumference of the inside of the housing, significantly improving the reliability of the connection between the second connection section and the housing. Furthermore, this design allows the current collector component to cover the opening of the housing, thus providing a seal.

[0025] In some embodiments, the current collector component comprises several second connection sections, the multiple second connection sections being spaced apart from one another along the circumferential direction of the inside of the housing. In this embodiment, the current collector component comprises several second connection sections, thereby facilitating precise alignment of the weld between the current collector component and the inside of the housing.

[0026] In some embodiments, any two adjacent second weld sections are spaced at equal angular intervals along the circumferential direction of the inside of the housing.

[0027] In some embodiments, every second connection section is welded to the inside of the housing to form a first weld section. This design ensures that the force of gravity exerted on the current collector component by the electrode assembly, combined with the current collector component's own weight, is distributed evenly across multiple first weld sections. This reduces the likelihood of weld failure at the first weld section between the second connection section and the housing due to uneven stress distribution, further improving the reliability of the connection between the current collector component and the housing.

[0028] In some embodiments, the housing comprises a circumferential side wall, wherein the inside of the circumferential side wall forms the inside of the housing, wherein the thickness of the circumferential side wall is a first thickness H1, the thickness of the second connecting section is a second thickness H2, where 0.3 ≤ H1 / H2 ≤ 3.

[0029] In the aforementioned technical solution, this configuration firstly helps to prevent laser perforation due to the excessively thin circumferential side wall of the housing during welding, thus reducing the risk of battery leakage; secondly, it ensures that the second connection section has high structural strength, making the weld between the second connection section and the housing tear-resistant even when the battery cell is subjected to vibrations.

[0030] In some embodiments, 0.8 ≤ H1 / H2 ≤ 2.75. Extensive experimental analyses carried out by the inventor of the present application have shown that it better meets both the strength requirements of the second connection section and the thickness requirements of the circumferential side wall if the ratio of the first thickness H1 to the second thickness H2 is 0.8 ≤ H1 / H2 ≤ 2.75.

[0031] In some embodiments, 0.2 mm ≤ H1 ≤ 0.6 mm and / or 0.2 mm ≤ H2 ≤ 0.6 mm. This design makes it easier to ensure that the ratio H1 / H2 between the first thickness H1 and the second thickness H2 satisfies either 0.3 ≤ H1 / H2 ≤ 3 or 0.8 ≤ H1 / H2 ≤ 2.75.

[0032] In some embodiments, the first connection section is circular, with a diameter greater than or equal to 15 mm and less than or equal to 100 mm, and a height of the second connection section along the axial direction of the electrode assembly greater than or equal to 0.1 mm and less than or equal to 10 mm. Thus, the height of the second connection section is appropriate, giving it high structural strength while avoiding excessive space occupancy in the vertical direction of the battery cell, thereby ensuring that the battery cell has a high energy density.

[0033] In some embodiments, the housing has an opening and an opening end surface surrounding the opening, wherein the end surface of the second connecting section facing away from the first connecting section is flush with the opening end surface of the housing, or the end surface of the second connecting section facing away from the first connecting section is closer to the electrode assembly than the opening end surface of the housing, wherein along the axial direction of the electrode assembly the distance between the end surface of the second connecting section facing away from the first connecting section and the opening end surface of the housing is L1, where 0 mm ≤ L1 ≤ 2 mm.

[0034] In the aforementioned technical solution, precise alignment of the current collector component's installation position is facilitated if the end face of the second connection section, facing away from the first connection section, is flush with the opening end face of the housing. If the distance L1 between the end face of the second connection section, facing away from the first connection section, and the opening end face of the housing is 0 mm ≤ L1 ≤ 2 mm, the second connection section of the current collector component is prevented from protruding beyond the housing. This ensures that the end cap can contact the opening end face to seal the opening when the battery cell is fitted with an end cap.

[0035] In some embodiments, the housing has an opening and an opening end face surrounding the opening, the battery cell further comprising an end cap covering the opening, the end cap being welded to the opening end face of the housing to form a second weld section, with a gap along the axial direction of the electrode assembly between the first weld section and the second weld section. This prevents the laser beam from being projected onto the first weld section when the second weld section is formed by laser melting of the end cap and the housing, thus preventing the second weld section from interfering with the first.

[0036] In some embodiments, part of the end cap overlaps the opening end surface of the housing, with the second weld section being formed by emitting a laser beam parallel to the opening end surface to melt the end cap and the housing.

[0037] In some embodiments, the housing has an opening and an opening end surface surrounding the opening, wherein the battery cell further comprises an end cap covering the opening, the end cap being welded to the opening end surface of the housing to seal the opening, the end cap comprising a projecting section extending towards the interior of the housing, a gap being provided between the projecting section and the interior of the housing, and the second connecting section being at least partially housed in the gap.

[0038] By positioning the protruding section on the surface of the end cap facing the interior of the housing, the structural strength of the end cap is increased, thereby improving the safety performance of the battery cell. However, if the second welding section is configured so that the laser beam is emitted parallel to the opening end face to melt the end cap and the housing, and if the laser beam is again emitted parallel to the opening end face after the end cap has been attached to the housing, the protruding section can obstruct the laser beam.

[0039] In some embodiments, the projecting section contacts the surface of the first connection section facing away from the electrode assembly, or the distance between the projecting section and the first projecting section along the axial direction of the electrode assembly is L2, where 0 mm ≤ L2 ≤ 1 mm. Consequently, the gap between the projecting section and the side of the first connection section facing away from the electrode assembly is small. This prevents excessive compression of the first connection section by the projecting section, thus preventing the weld between the second connection section and the housing from cracking. Furthermore, the space occupied by the gap in the vertical direction of the battery cell is reduced, allowing for a higher capacity of the active material within the battery cell. This ensures that the battery cell has a high energy density.

[0040] In some embodiments, the base material of the housing differs from the base material of the current collector component, with the melting point of the housing base material being higher than that of the current collector component. This design ensures that the melting point of the current collector component is lower than that of the housing. Consequently, when welding the current collector component to the inside of the housing, the housing is less susceptible to breakdown from within the housing, effectively reducing the risk of electrolyte leakage from the housing.

[0041] In some embodiments, the coefficient of thermal expansion of the housing base material is smaller than the coefficient of thermal expansion of the power collector component base material.

[0042] In some embodiments, the base material of the casing is steel, while the base material of the current collector component is copper or aluminum. This design not only solves the problem of electrolyte leakage from battery cells but also enables high structural strength of the casing, thereby increasing the safety of the battery cell and simultaneously reducing its manufacturing costs.

[0043] In some embodiments, the surface of the housing and / or the current collector component is coated with a layer of solder. This brazing layer facilitates improved welding results between the current collector component and the housing.

[0044] In some embodiments, the housing comprises a base layer, the solder layer being arranged on the base layer, and part of the first weld section being located within the base layer. Given the small thickness of the solder layer, the design of the portion of the first weld section located within the base layer allows the current collector component to be welded to the base layer of the housing, thereby improving the reliability of the connection between the current collector component and the housing.

[0045] In some embodiments, the first weld segment does not penetrate the base layer of the housing. Given the small thickness of the brazing alloy layer, the design of the first weld segment to not penetrate the base layer of the housing further ensures that the first weld segment does not penetrate the housing. This reduces the likelihood of cracking in the first weld segment and electrolyte leakage outside the housing.

[0046] In the second aspect, the embodiment of the present application provides a battery comprising the battery cell provided by the embodiment of the present application in the first aspect.

[0047] In the third aspect, the embodiment of the present application provides an electrical device comprising the battery provided by the embodiment of the present application in the second aspect.

[0048] An exemplary manufacturing process for the battery cell is described, wherein the manufacturing process comprises the following: providing an electrode assembly, wherein the electrode assembly has an electrode tab; providing a housing; providing a current collector component; connecting the current collector component to the electrode tab, wherein the electrode assembly and the current collector component are housed in the housing; welding the current collector component to the inside of the housing to form a first weld section, wherein the weld penetration depth of the first weld section formed on the housing is less than the thickness of the housing.

[0049] In some embodiments, the step of connecting the current collector component to the electrode tab, wherein the electrode assembly and the current collector component are housed in the housing, comprises in particular connecting the current collector component to the electrode tab, wherein the electrode assembly connected to the current collector component is housed in the housing; or arranging the electrode assembly in the housing, wherein the current collector component is housed in the housing and the current collector component is connected to the electrode tab.

[0050] In some embodiments, the step of welding the current collector component to the inside of the housing to form a first weld section comprises, in particular, emitting a laser beam from inside the housing along a direction perpendicular to the axial direction of the electrode assembly to melt the housing and the current collector component and to form the first weld section; or emitting a laser beam along a direction parallel to the axial direction of the electrode assembly to melt the housing and the current collector component and to form the first weld section.

[0051] In some embodiments, the manufacturing process comprises, after welding the current collector component to the inside of the housing to form a first weld section, wherein the weld penetration depth of the first weld section formed on the housing is less than the thickness of the housing, further providing an end cap; and welding the end cap to the opening end face of the housing to form a second weld section, wherein there is a gap between the first weld section and the second weld section along the axial direction of the electrode assembly.

[0052] In some embodiments, the step of welding the end cap to the opening end face of the housing to form a second weld section comprises, in particular, overlapping part of the end cap onto the opening end face of the housing; and emitting a laser beam parallel to the opening end face of the housing to melt the end cap and the housing, thereby forming the second weld section.

[0053] The foregoing description merely provides an overview of the technical solutions of the present application. To facilitate a clearer understanding of the technical means employed herein, implementation can be carried out in accordance with the content of the description. To make the aforementioned and other objectives, features, and advantages of the present application clearer and more comprehensible, specific embodiments of the present application are described below. FIGURES

[0054] In the figures, the same reference numerals in several figures denote identical or similar components or elements, unless otherwise indicated. These figures are not necessarily to scale. It is understood that these figures merely illustrate some embodiments of the present application and should not be interpreted as limiting the scope of the present application. Fig. Figure 1 is a schematic representation of a partial cross-section of a state-of-the-art battery cell; Fig. Figure 2 is a schematic representation of the structure of a vehicle in some embodiments of the present application; Fig. Figure 3 is an exploded view of a battery in some embodiments of the present application; Fig. Figure 4 is a schematic exploded view of the structure of a battery cell in some embodiments of the present application; Fig. 5 is a main view of the battery cell in Fig. 4; Fig. Figure 6 is a schematic representation of a cross-section of the battery cell along the AA direction in Fig. 5; Fig. 7 is a partially enlarged view at B in Fig. 6; Fig. Figure 8 is a schematic representation of the structure of a current collector component of the battery cell in an embodiment of the present application; Fig. Figure 9 is a schematic representation of the structure of another current collector component of the battery cell in an embodiment of the present application; Fig. 10 is a partially schematic view of the connection between the second connection section and the housing of the battery cell according to another embodiment in an embodiment of the present application; Fig. 11 is a schematic representation of the structure of another current collector component of the battery cell in an embodiment of the present application; Fig. 12 is a partially schematic view of the connection between the second connection section and the housing of the battery cell according to a further embodiment in an embodiment of the present application; Fig. 13 and Fig. Figure 14 is a partially schematic view of the connection between the second connection section and the housing of the battery cell according to a further embodiment in an embodiment of the present application; Fig. Figure 15 is a flowchart of the battery cell manufacturing process; Fig. Figure 16 is a flowchart of the battery cell manufacturing process. SPECIFIC EXECUTION FORMS

[0055] The embodiments of the technical solutions of the present application are now described in detail with reference to the figures. The following embodiments serve only to describe the technical solution of the present application more clearly; therefore, they should be considered merely as examples and not intended to limit the scope of protection of the present application.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as they are generally understood by those skilled in the technical field of the present application; the terms used herein serve solely to describe specific embodiments and are not intended to limit the present application; the terms "comprise" and "include" and all variations thereof in the description, the claims and the figures above are intended to cover non-exclusive inclusion.

[0057] In the description of embodiments of the present application, technical terms such as "first" and "second" are used solely to distinguish between different objects and should not be interpreted as indicating or suggesting a relative meaning, nor as indicating the number, specific sequence, or hierarchical relationship of the specified technical features. In the description of embodiments of the present application, "multiple" means at least more than two, unless expressly and specifically limited otherwise.

[0058] The term "embodiment," as used here, implies that the specific features, structures, or properties described in connection with an embodiment may be included in at least one embodiment of the present application. The occurrence of this term in different places in the description does not necessarily refer to the same embodiment, nor does it denote independent or alternative embodiments that are mutually exclusive with other embodiments. It is expressly and implicitly known to those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0059] It is understood that the term "and / or" used in the description of the embodiments of the present application represents only an associative relationship describing related objects, and that the use of this term indicates that three relationships are possible. For example, the expression "A and / or B" can be understood to mean three possibilities: the presence of A alone, the simultaneous presence of A and B, and the presence of B alone. Furthermore, the symbol " / " here generally indicates that the related objects before and after it are in an "or" relationship.

[0060] In the description of embodiments of the present application, the term “several” means two or more (including two), likewise “several sets” means two or more sets (including two sets) and “several parts” means two or more parts (including two parts).

[0061] In the description of the embodiments of the present application, it should be noted that terms such as "center", "longitudinal direction", "horizontal direction", "length", "width", "thickness", "top", "bottom", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial" and "circumferential" denote an orientation or positional relationship based on the orientation or positional relationship shown in the figures, and serve only to facilitate and simplify the description of the embodiments of the application and do not mean that the device or element in question must have a specific orientation, be constructed and function in a specific orientation, and therefore are not to be understood as limiting the embodiments of the application.

[0062] In the description of the embodiments of this application, it should be noted that the technical terms "mounted", "connected", "attached", etc. are to be understood in the broadest sense unless expressly stated otherwise and limited, e.g., they may refer to a fixed connection, a detachable connection, or an integral connection; they may also be mechanical or electrical connections; they may be direct connections or indirect connections via an intermediate medium, connections within two elements, or interactions between two elements. The specific meanings of the aforementioned terms in the embodiments of this application can be understood by general technical personnel in this field according to the specific situations.

[0063] Traction batteries have become a new trend in energy development due to their high energy density and environmentally friendly properties. As in Fig. 1 shown, is Fig. Figure 1 shows a schematic representation of a partial cross-section of a prior art battery cell. Currently, a battery cell 200a typically consists of a housing 21a, an electrode assembly 22a, a current collector component 24a, and an end cap 23a. The electrode assembly 22a consists of electrode plates and separating films. A film-free area is formed on the current collector of the electrode plate, the film-free area being flattened to form an electrode tab 221a. The electrode tab 221a is connected to the current collector component 24a, which in turn is connected to the end cap 23a. Thus, the electrode tab 221a, the current collector component 24a, the end cap 23a, and the housing 21a are connected sequentially to form a conductive path for the output of electrical energy.The current collector component 24a is typically made of copper, while the end cap 23a is usually made of steel. This configuration ensures electrical conductivity for both the current collector component 24a and the end cap 23a, while also providing the end cap 23a with high strength.

[0064] The assembly process for the aforementioned battery cell 200a essentially comprises: welding the electrode tab 221a of the electrode assembly 22a to the current collector component 24a; inserting the electrode assembly 22a, connected to the current collector component 24a, into the housing 21a; closing the end cap 23a onto the housing 21a and welding the end cap 23a to the housing 21a; subsequently, the end cap 23a is connected to the current collector component 24a by means of external laser welding. However, the inventor found that microcracks easily form at the weld point between the end cap 23a and the current collector component 24a, leading to a tendency for electrolyte to leak from the battery.

[0065] After careful investigation, the inventor determined that the causes for the formation of microcracks at the weld between the end cap 23a and the current collector component 24a are as follows: First, since the current collector component 24a is made of copper and the end cap 23a of steel, a significant discrepancy arises between the thermal expansion and thermal conductivity of copper and steel, with copper having a coefficient of thermal expansion approximately 40% higher than that of iron. This results in considerable stresses at the weld between the end cap 23a and the current collector component 24a, leading to cracks in the weld section 26a formed at the weld point; Second, during welding, the partial melting of the current collector component 24a produced liquid copper, which exhibits strong penetrating power towards steel.During solidification, it caused microcracks on the crystallization surface of the steel. In contrast, laser external welding joins the end cap 23a to the current collector component 24a. The laser beam passes through the end cap 23a, forming a weld section 26a between the end cap 23a and the current collector component 24a, with the weld section 26a penetrating the end cap 23a. Therefore, if cracks form in the weld section 26a, the end cap 23a cannot provide a reliable seal against the housing 21a. Electrolyte within the housing 21a can then escape from the cracks in the weld section 26a of the end cap 23a, resulting in electrolyte leakage.

[0066] To solve the technical problem, the inventor developed the idea of ​​designing the current collector component of the battery cell so that it is welded to the inside of the casing, with the weld seam formed between the current collector component and the casing not penetrating the casing. Therefore, even if microcracks occur at the weld point between the current collector component and the casing, the electrolyte cannot escape from the battery through the cracks in the weld seam.

[0067] Furthermore, the inventor determined that during battery cell assembly, the weld section formed between the end cap and the housing when welding the end cap to the housing could interfere with the weld section between the current collector component and the housing. Therefore, the inventor ultimately designed the weld section between the end cap and the housing to be spaced apart from the weld section between the current collector component and the housing.

[0068] The battery cells disclosed in the embodiments of the present application can be used in electrical devices such as vehicles, ships, or aircraft, but are not limited to such use. Power supply systems comprising the disclosed battery cells and batteries in the present application can be used to form the electrical device.

[0069] An electrical device that uses a battery as a power source in the embodiments of the present application can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric bicycles, electric vehicles, ships, spacecraft, etc. Among these, electric toys can include stationary or mobile electric toys, such as game consoles, electric toy cars, electric toy boats, and electric toy airplanes, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0070] To simplify the explanation, in the following exemplary embodiments an electrical device is described using the example of a vehicle 1000 in an exemplary embodiment of the present application.

[0071] As in Fig. 2 shown, is Fig. Figure 2 is a schematic representation of the structure of a vehicle 1000 in some embodiments of the present application. The vehicle 1000 can be a gasoline-powered vehicle, a gas-powered vehicle, or a new energy vehicle. New energy vehicles can include, among others, pure electric vehicles, hybrid vehicles, or range-extended vehicles. A battery 100 is arranged inside the vehicle 1000; the battery 1000 can be located at the bottom, at the front, or at the rear of the vehicle 1000. The battery 100 can be used to supply power to the vehicle 1000; for example, the battery 100 can serve as the operating current source for the vehicle 1000.The vehicle 1000 can also include a control unit 200 and a motor 300, the control unit 200 being used to control the power supply to the motor 300 by the battery 100, for example for starting, navigation and operation of the vehicle 1000 while driving.

[0072] In some embodiments of the present application, the battery 100 can not only be used as an operating current source for the vehicle 1000, but can also be used as a drive current source for the vehicle 1000 in order to provide the drive power for the vehicle 1000 instead of or partially instead of fuel or natural gas.

[0073] As in Fig. 3 shown, is Fig. Figure 3 shows an exploded view of a battery 100 in some embodiments of the present application. The battery 100 comprises a box 10 and a battery cell 20, the battery cell 20 being housed in the box 10. The box 10 serves to provide a receiving space for the battery cell 20, and the box 10 can be constructed in various ways. In some embodiments, the box 10 can comprise a first section 11 and a second section 12, the first section 11 and the second section 12 being superimposed on each other. Together, the first section 11 and the second section 12 form a receiving space for the battery cell 20. The second section 12 can be a hollow structure open at one end, while the first section 11 can be a plate-like structure.The first section 11 overlaps the open side of the second section 12, so that the first section 11 and the second section 12 together form a receiving space; alternatively, both the first section 11 and the second section 12 can be hollow structures with one open side, the open side of the first section 11 overlapping the open side of the second section 12. Naturally, the box 10 consisting of the first section 11 and the second section 12 can have various shapes, for example, a cylinder, a cuboid, etc.

[0074] Within the battery 100, several battery cells 20 can be arranged, with several battery cells 20 connected in series, parallel, or a mixed configuration. A mixed configuration means that several battery cells 20 are connected both in series and in parallel. Several battery cells 20 can be connected directly in series, parallel, or a mixed configuration, with the assembled structure of battery cells 20 then housed in the box 10; alternatively, the battery 100 can be a battery module consisting of several battery cells 20 initially connected in series, parallel, or a mixed configuration, with several battery modules then connected in series, parallel, or a mixed configuration to form an integrated assembly housed in the box 10.The battery 100 may also include other structures, such as busbars to enable electrical connections between multiple battery cells 20.

[0075] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited to these.

[0076] The specific structure of battery cell 20 is described in detail below with reference to the figures.

[0077] As in the Fig. 4, Fig. 5, Fig. 6 to Fig. 7 shown, is Fig. 4 a schematic exploded view of the structure of a battery cell 20 in some embodiments of the present application. Fig. 5 is a main view of battery cell 20 in Fig. 4. Fig. Figure 6 is a schematic representation of a cross-section of the battery cell 20 along the AA direction in Fig. 5. Fig. 7 is a partially enlarged view at B in Fig. 6.

[0078] As in the Fig. 4, Fig. 5, Fig. 6 to Fig. As shown in Figure 7, in some embodiments of the present application, the battery cell 20 comprises an electrode assembly 22, a housing 21, and a current collector component 24, wherein the electrode assembly 22 has an electrode tab, the housing 21 is used to receive the electrode assembly 22, and the current collector component 24 is housed in the housing 21 and connected to the electrode tab. The current collector component 24 is welded to the inside of the housing 21 to form a first weld section 26, wherein the weld penetration depth d1 of the first weld section 26 formed on the housing 21 is less than the thickness H1 of the housing 21.

[0079] A battery cell 20 is the smallest unit comprising the battery 100. The electrode assembly 22 is a component within the battery cell 20 in which electrochemical reactions take place. The electrode assembly 22 can comprise a main body section and an electrode tab, the electrode tab extending from the main body section such that it protrudes beyond the end of the main body section. The electrode assembly 22 can comprise a positive electrode plate, a negative electrode plate, and a separator film. The electrode assembly 22 can be a wound structure formed by winding a positive electrode plate, a negative electrode plate, and a separator film. The electrode assembly 22 can also be a laminated structure formed by stacking a positive electrode plate, a negative electrode plate, and a separator film.The positive electrode plate comprises a positive current collector and positive active material layers coated on opposite sides of the positive current collector. The negative electrode plate comprises a negative current collector and negative active material layers coated on opposite sides of the negative current collector. The main body section corresponds to the area of ​​the electrode assembly 22 where the active material layer is coated onto the electrode plate, while the electrode tab forms the area of ​​the electrode plate where no active material layer is coated.

[0080] The electrode tab can be divided into positive electrode tabs and negative electrode tabs, whereby the positive electrode tabs and negative electrode tabs can be arranged at both ends of the main body section or at one end of the main body section.

[0081] The current collector component 24 can be specifically connected to either the positive electrode tab or the negative electrode tab. In the case of the current collector component 24 connected to the positive electrode tab, the current collector component 24 is welded to the housing 21. Thus, the electrode assembly 22, the positive electrode tab, the current collector component 24, and the housing 21 are connected sequentially to form a conductive path. Simultaneously, the battery cell 20 can also include a pole rod 25. The pole rod 25 can be connected to either the positive or negative electrode tab. In the case of the pole rod connected to the negative electrode tab, the electrode assembly 22, the negative electrode tab, and the pole rod 25 are thus connected sequentially to form a conductive path for the output of electrical energy.It is understood that the pole rod 25 is insulated from the housing 21 to prevent a short circuit of the battery cell 20.

[0082] The interior of the housing 21 can have a cavity for receiving the electrode assembly 22. The shape of the housing 21 is not restricted. For example, it can be cylindrical, as shown in Fig. 4 shown, or alternatively rectangular, hexagonal prism, etc. If the housing 21 has a cylindrical shape, its inner surface forms a curved surface. It is understood that the electrode assembly 22 is housed in the cavity, the axial direction of the electrode assembly 22 being the Z-direction, as shown in Fig. 4 shown.

[0083] The current collector component 24 can be welded to the inside of the housing 21. During welding, parts of the current collector component 24 and parts of the housing 21 melt, with the molten parts forming a first weld section 26. The first weld section 26 can be formed, for example, by irradiating the current collector component 24 with ultrasonic waves or a laser beam. The weld penetration depth d1 formed by the first weld section 26 on the housing 21 is less than the thickness H1 of the housing 21. Here, the weld penetration depth d1 formed by the first weld section 26 on the housing 21 refers to the distance from the lowest point of the weld area formed on the housing 21 to the surface of the housing 21. Thus, when the current collector component 24 is welded to the housing 21, the first weld section 26 between the two does not penetrate the housing 21.

[0084] In summary, the current collector component 24 is welded to the inside of the housing 21 by a structure of the battery cell 20 in this embodiment to form a first weld section 26, wherein the weld penetration depth d1 of the first weld section 26 formed on the housing 21 is less than the thickness H1 of the housing 21. Thus, the housing 21 is not penetrated during welding, and the first weld section 26 cannot penetrate the housing 21 either. Even if a crack forms at the weld point, namely at the first weld section 26, between the current collector component 24 and the housing 21, the electrolyte inside the battery cell 20 cannot escape through the crack to the outside of the housing 21, thereby effectively reducing the risk of electrolyte leakage.

[0085] In some embodiments of the present application, the housing 21 has an opening, wherein the electrode tab is located at the end of the electrode assembly 22 that is closest to the opening.

[0086] In some embodiments, the housing 21 has an opening and a cavity used to accommodate electrode assemblies, wherein the opening of the housing 21 can be connected to the cavity, and the electrode assembly 22 and the current collector component 24 can be mounted from the opening into the cavity during the assembly of the battery cell 20.

[0087] It should be noted that the electrode tab located at the end of the electrode assembly 22 closest to the opening can be understood in a broader sense. That is, it can be understood that both the positive and negative electrode tabs are located at the end of the electrode assembly 22 closest to the opening. In this case, the positive and negative electrode tabs are located on the same side of the electrode assembly 22, which helps to reduce the space occupied by the electrode tab within the housing 21.Alternatively, it can be assumed that one of the positive electrode tabs and negative electrode tabs connected to the current collector component 24 is located at the end of the electrode assembly 22 that is closer to the opening, while the other positive electrode tab and negative electrode tab is located at the end of the electrode assembly 22 that is farther from the opening. In this case, the positive electrode tab and negative electrode tab are located on opposite sides of the main body section of the electrode assembly 22.

[0088] In this way, the electrode tab, which is intended at least for connection with the current collector component 24, is positioned close to the opening on the electrode assembly 22. This facilitates the electrical connection between the current collector component 24 and the electrode tab during the assembly of the battery cell 20, resulting in convenient and efficient assembly.

[0089] According to some embodiments of the present application, the inside of the housing 21 comprises a first surface and a second surface, wherein the first surface is arranged opposite the electrode assembly 22, the second surface is located on a side of the first surface that approaches the opening of the housing 21, wherein the orthogonal projection of the first surface along the axial direction of the electrode assembly 22 overlaps with the orthogonal projection of the second surface along the axial direction of the electrode assembly 22; the first weld section 26 is formed on the second surface of the housing 21, namely, the current collector component 24 is welded to the second surface to form a first weld section 26.

[0090] In some embodiments, the housing 21 can, for example, but not limited to, have a cylindrical shape. For example, the housing 21 is cylindrical, wherein the first surface and the second surface are curved surfaces and the orthogonal projection of the first surface along the axis of the housing overlaps with the orthogonal projection of the second surface along the axis of the housing.

[0091] This design ensures that the current collector component 24 can be welded to the inside of the housing 21 without requiring any structural changes to the housing 21 itself, thereby reducing costs.

[0092] As in the Fig. 4, Fig. 5, Fig. 6 to Fig. As further shown in Figure 7, the current collector component 24 according to some embodiments of the present application comprises a first connecting section 241 and a second connecting section 242 connected thereto, wherein the first connecting section 241 is connected to the electrode tab, the second connecting section 242 engages with the inside of the housing 21 and the second connecting section 242 is welded to the inside of the housing 21 to form at least one first welded section 26.

[0093] In some embodiments, the first connecting section 241 can also be welded to the electrode tab. According to some embodiments of the present application, the assembly process of the current collector component 24 with the housing 21 can include the following cases: In the first case, the first connecting section 241 is welded to the electrode tab, thereby connecting the current collector component 24 to the electrode assembly 22. The connected current collector component 24 and the electrode assembly 22 are then installed in the cavity, after which the second connecting section 242 is welded to the housing 21; In the second case, the electrode assembly 22 is installed in the cavity, followed by the installation of the current collector component 24 in the cavity. Subsequently, the first connecting section 241 is welded to the electrode tab and the second connecting section 242 is welded to the housing 21.

[0094] The second connecting section 242 engages with the inside of the housing 21, which can mean: configuring the shape and dimensions of the second connecting section 242 based on the shape and dimensions of the inside of the housing 21, so that the second connecting section 242 can be welded to the inside of the housing 21. In other words, without changing the structure of the housing 21, the shape and dimensions of the current collector component 24 are configured to fit the inside of the housing 21, thus enabling the second connecting section 242 to be welded to the inside of the housing 21. Using the example of a cylindrical battery, the housing 21 of the cylindrical battery is a cylinder, with the inside of the housing 21 being a curved surface.The solution in the embodiment of the present application does not change the cylindrical housing 21, but instead adapts the shape and dimensions of the current collector component 24 to the curved inside of the housing 21, thereby enabling the current collector component 24 to be welded to the curved inside of the housing 21.

[0095] This design ensures that the current collector component 24 can be connected to the electrode tab via the first connection section 241 to achieve electrical conductivity. Simultaneously, the current collector component 24 can be welded to the inside of the housing by configuring the second connection section of the current collector component to engage with the inside of the housing. Consequently, no structural modifications to the housing 21 are required.

[0096] In some embodiments, both the first connection section 241 and the second connection section 242 can have a plate-like configuration, with the second connection section 242 surrounding the outside of the first connection section 241, thus forming the current collector component 24 into a flat plate structure. In this embodiment, the outside of the second connection section 242 is welded to the inside of the housing 21. In this case, for example, by irradiating the current collector component 24 with a laser, the laser beam can be projected along the axial direction Z parallel to the electrode assembly 22 between the second connection section 242 and the housing 21. This causes the second connection section 242 and the housing 21 to melt, thereby forming the first weld section 26.

[0097] According to some embodiments of the present application, the second connecting section 242 is arranged at the outer edge of the first connecting section 241 and the second connecting section 242 is located on one side of the plane in which the first connecting section 241 lies.

[0098] In some embodiments, the second connecting section 242 can project beyond the first connecting section 241 and extend forward towards the opening, which facilitates the welding connection between the second connecting section 242 and the inside of the housing 21.

[0099] Using the example of forming a first weld section 26 by irradiating the current collector component 24 with a laser, the laser beam can be projected along the axial direction Z parallel to the electrode assembly 22 between the second connection section 242 and the housing 21 to form the first weld section 26; alternatively, the laser beam can be projected along a direction perpendicular to the axial direction Z of the electrode assembly 22 onto the second connection section 242, melting a part of the second connection section 242 and the housing 21 to form the first weld section 26.

[0100] Thus, the second connecting section 242 extends beyond the first connecting section 241, which facilitates the adaptation of the second connecting section 242 to the inside of the housing 21 and makes it possible to conveniently weld the second connecting section 242 to the housing 21.

[0101] According to some embodiments of the present application, in an implementation where the second connecting section 242 is located on one side of the plane in which the first connecting section 241 lies, at least a portion of the outer surface of the second connecting section 242 is configured to abut the inner surface of the housing 21. This ensures that the second connecting section 242 can be welded to the housing 21. In this embodiment, the second connecting section 242 has an outer surface and an inner surface, the outer surface of the second connecting section 242 being a surface of the second connecting section 242 that faces the inner surface of the housing 21.

[0102] In some embodiments, the shape and dimensions of the second connecting section 242 are designed to fit the inside of the housing 21, so that the outside of the second connecting section 242 can abut the inside of the housing 21. As in the Fig. 6 and Fig. As shown in Figure 7, the housing 21 can have a cylindrical shape. The first surface on the inner surface of the housing 21, which is intended to abut the second connecting section 242, forms a curved surface together with the other parts of the inner surface of the housing 21.

[0103] Consequently, the configuration in which at least part of the outside of the second connection section rests against the inside of the housing facilitates the welding connection between the second connection section and the inside of the housing.

[0104] According to some embodiments of the present application, the outside of the second connecting section 242 is completely in contact with the inside of the housing 21.

[0105] It is understood that the outside of the second connecting section 242 can be fully in contact with the inside of the housing 21; alternatively, only part of the outside of the second connecting section 242 is in contact with the inside of the housing 21.

[0106] By configuring the second connection section so that its outer surface rests completely against the inside of the housing, the stability of the welded connection between the second connection section and the inside of the housing can be further improved.

[0107] According to some embodiments of the present application, as in Fig. As shown in Figure 8, the first connecting section 241 is a flat plate structure, wherein the outside of the second connecting section 242 has a first projection on the plane in which the first connecting section 241 lies, the first projection overlapping with the outside of the first connecting section 241, the outside of the first connecting section 241 being a surface that feeds the inside of the housing 21.

[0108] The second connection section 242 can be configured to project from the surface of the first connection section 241 facing away from the electrode assembly 22, with the outer surface of the second connection section 242 being coplanar with the outer surface of the first connection section 241. In this configuration, both the outer surface of the second connection section 242 and the outer surface of the first connection section 241 can be in contact with the inner surface of the housing 21.

[0109] By constructing the outer surface of the second connecting section 242 such that its orthogonal projection onto the plane of the first connecting section 241 overlaps with the outer surface of the first connecting section 241, both the second connecting section 242 and the first connecting section 241 can be firmly pressed against the inside of the housing 21 for the weld joint. This improves the stability of the weld joint on the inside of the current collector component.

[0110] According to some other embodiments of the present application, as in Fig. As shown in Figure 9, the structure of the current collector component 24 can additionally be configured such that the inside of the second connection section 242 has a second projection on the plane in which the first connection section 241 lies, with the second projection overlapping the outside of the first connection section 241. That is, the inside of the second connection section 242 connects with the outside of the first connection section 241. At this point, the outside of the first connection section 241 does not touch the inside of the housing 21.

[0111] According to some embodiments of the present application, the first weld section 26 does not penetrate the second connection section 242 along the axial direction of the electrode assembly 22.

[0112] This means that the weld penetration depth d2 formed by the first weld section 26 on the second connection section 242 is smaller than the dimension h of the second connection section 242 along the axial direction Z of the electrode assembly 22.

[0113] As described above, the direction of the laser irradiation is not restricted, as in the example of forming the first weld section 26 by irradiating the current collector component 24 with a laser beam. If the outside of the second connection section 242 is completely in contact with the inside of the housing 21, for example in the Fig. In the example shown in Figure 7, the laser beam can be projected along a direction perpendicular to the axial direction Z of the electrode assembly 22 onto the second connection section 242. The laser beam penetrates the second connection section 242 and is projected onto the inside of the housing 21, melting parts of the second connection section 242 and parts of the housing 21 to form the first weld section 26. Here, the weld penetration depth d1 formed by the first weld section 26 on the housing 21 refers to the distance from the lowest point of the weld area formed on the housing 21 to the inside of the housing 21.

[0114] For example, in the Fig. In the example shown in Figure 10, the laser beam is projected along a direction parallel to the axial direction Z of the electrode assembly 22 onto the second connection section 242 and the housing 21, melting parts of the second connection section 242 and the housing 21 to form the first weld section 26. In this example, the first weld section 26 is configured such that it does not penetrate the second connection section 242 along the axial direction Z of the electrode assembly 22.

[0115] This design ensures that the laser beam does not pass through the second connection section 242 when the laser beam is projected along a direction parallel to the axial direction Z of the electrode assembly 22 onto the second connection section 242 and the housing 21 to form the first weld section 26. This prevents the laser beam from passing through the current collector component and being projected onto the electrode assembly 22, thus preventing damage to the electrode assembly 22.

[0116] In some embodiments of the present application, in which only a part of the outside of the second connecting section 242 is in contact with the inside of the housing 21, the second connecting section 242 can be configured to include a contact section and a guide section, wherein the contact section engages with the inside of the housing 21 and at least one section of the contact section is welded to the inside of the housing 21, wherein one end of the guide section is connected to the contact section, and the other end of the guide section is connected to the first connecting section 241, wherein the distance between the guide section and the inside of the housing 21 gradually increases from one end to the other end of the guide section.

[0117] Thus, only part of the contact section on the second connection section 242 is welded to the inside of the housing 21, or the entire contact section is welded to the inside of the housing 21, while the guide section is not connected to the inside of the housing 21. The other end of the guide section can be connected to the outer edge of the first connection section 241, or the other end of the guide section can be connected to the middle section of the first connection section 241, and the other end of the guide section is then not located at the outer edge of the first connection section 241; the second connection section 242 is not integrally arranged at the outer edge of the first connection section 241.

[0118] This design ensures that the second connection section 242 not only has a contact section for the weld connection with the outside of the housing 21, but also a guide section. This guide section approaches the central axis of the electrode assembly 22 from one end to the other. When the current collector component 24 is installed in the housing 21 in this example, the guide section can perform a guiding function to facilitate the installation of the current collector component 24 and thus achieve high assembly efficiency.

[0119] According to some embodiments of the present application, the first weld section 26 does not penetrate the contact section of the second connection section 242 along the axial direction of the electrode assembly 22.

[0120] In this case, the weld penetration depth formed by the first weld section 26 at the contact section is smaller than the dimension of the contact section along the axial direction Z of the electrode assembly 22.

[0121] As described above, the direction of laser irradiation is not restricted, as in the example of forming the first weld section 26 by irradiating the current collector component 24 with a laser beam. If the second connection section 242 comprises a guide section and a contact section, the laser beam can be projected onto the contact section along a direction perpendicular to the axial direction Z of the electrode assembly 22. The laser beam then passes through the contact section and is projected onto the inside of the housing 21.

[0122] In some other embodiments, the laser beam can alternatively be projected onto the contact section and the housing 21 along a direction parallel to the axial direction Z of the electrode assembly 22, if the second connecting section 242 comprises a guide section and a contact section, causing parts of the contact section and the housing 21 to melt and form the first weld section 26.

[0123] This design ensures that the laser beam does not pass through the contact section when the laser beam is projected along a direction parallel to the axial direction Z of the electrode assembly 22 onto the contact section and the housing 21 to form the first weld section 26. This prevents the laser beam from passing through the current collector component and being projected onto the electrode assembly 22, thus preventing damage to the electrode assembly 22.

[0124] According to some embodiments of the present application, the first connecting section 241 can be firmly connected to the second connecting section 242 via a connecting piece, or the second connecting section 242 and the first connecting section 241 are formed as one manufactured part by an integral forming process.

[0125] It is understood that the connection method between the first connection section 241 and the second connection section 242 is not restricted. For example, if the first connection section 241 and the second connection section 242 are firmly connected to each other via a connector, the connector can be a screw, thus bolting the first connection section 241 to the second connection section 242. Alternatively, the connector can be a weld, thus welding the first connection section 241 to the second connection section 242.

[0126] On the one hand, the assembly process for the first connection section 241 and the second connection section 242 will be eliminated, which contributes to improving the assembly efficiency of the battery cell 20; on the other hand, without increasing costs, the structural strength of the current collector component 24 can be effectively improved if the first connection section 241 and the second connection section 242 are formed as one manufactured part by an integral forming process.

[0127] The number of second connection sections 242 of the current collector component 24 is not limited. According to some embodiments of the present application, as in Fig. As shown in Figure 11, the current collector component 24 can only comprise a second connection section 242, wherein the second connection section 242 is an annular structure extending along the circumferential direction of the inside of the housing 21.

[0128] In some embodiments, the outer surface of the second connecting section 242 is annular, with the second connecting section 242 surrounding the entire outer surface of the first connecting section 241. If the second connecting section 242 projects beyond the first connecting section 241 and extends towards the opening, the second connecting section 242 is connected to the entire circumference of the first connecting section 241.

[0129] This design allows the second connecting section 242 for the weld connection to fit snugly against the entire circumference of the inside of the housing 21, thereby improving the connection stability.

[0130] According to some other embodiments of the present application, the second connecting section 242 is welded to the inside of the housing 21 when the current collector component 24 has only one second connecting section 242. Several first weld sections 26 can be formed between the second connecting section 242 and the housing 21, the several first weld sections 26 being spaced apart from one another along the circumferential direction of the inside of the housing 21. That is, several points on the second connecting section 242 are welded to the inside of the housing 21.

[0131] In some embodiments, intermittent welding can be used to connect the second connecting section 242 to the housing 21, thereby forming several first weld sections 26 between the second connecting section 242 and the housing 21.

[0132] Consequently, several first weld sections 26 are formed between the second connection section 242 and the inside of the housing 21. This increases the number of connection points between the second connection section 242 and the housing 21, thereby improving the reliability of the connection between the second connection section 242 and the housing 21. If, in this embodiment, the battery cell 20 is installed in the box with the opening of the housing 21 facing downwards, the force of gravity on the electrode assembly 22 acts on the current collector component 24. Due to the presence of several first weld sections 26, the force of gravity exerted on the current collector component 24 by the electrode assembly 22 and the weight of the current collector component 24 itself are distributed across these several first weld sections 26.This prevents excessive stress on the first weld section 26, which can cause cracks at the weld point between the current collector component 24 and the housing 21.

[0133] According to some embodiments of the present application, at least two first weld sections 26 of the several first weld sections 26 are arranged symmetrically along the central axis of the housing 21.

[0134] It is understood that only two first weld sections 26 of all first weld sections 26 are arranged symmetrically along the central axis of the housing 21. Alternatively, all first weld sections 26 can comprise several groups of first weld sections 26, each group of first weld section 26 consisting of both first weld sections 26 arranged symmetrically along the central axis of the housing 21. In other words, all two first weld sections 26 in N first weld sections 26 are arranged symmetrically along the central axis of the housing 21, where N ≥ 4 and N is an even number.

[0135] This configuration in this embodiment ensures that at least two first weld sections 26 of the multiple first weld sections 26 are distributed and symmetrically arranged along the central axis of the housing 21, thereby improving the reliability of the connection between the current collector component 24 and the housing 21.

[0136] According to some embodiments of the present application, any two adjacent first weld sections 26 can be spaced apart at equal angular intervals along the circumferential direction of the inside of the housing 21.

[0137] In other words, the several first weld sections 26 between the second connecting section 242 and the housing 21 are evenly distributed around the central axis of the housing 21.

[0138] In this way, on the one hand, the dispersed arrangement of all first weld sections 26 prevents interference between several first weld sections 26, and on the other hand, the force of gravity exerted by the electrode assembly 22 on the current collector component 24, in combination with the weight of the current collector component 24 itself, acts evenly on several first weld sections 26. This reduces the probability of a weld crack at the first weld section 26 between the second connection section 242 and the housing 21 due to an uneven stress distribution, thereby further improving the reliability of the connection between the current collector component 24 and the housing 21.

[0139] According to some embodiments of the present application, the second connecting section 242 is welded to the inside of the housing 21 when the current collector component 24 has only one second connecting section 242. Several first weld sections 26 can be formed between the second connecting section 242 and the housing 21, the first weld section 26 being an annular structure extending along the circumferential direction of the inside of the housing 21, with the second connecting section 242 being sealed to the housing 21.

[0140] That is, as in Fig. As shown in Figure 10, the first weld section 26 can seal the gap between the second connection section 242 and the inside of the housing 21 when the second connection section 242 is welded to the entire circumference of the inside of the housing 21, thus achieving a tight connection between the second connection section 242 and the housing 21. The current collector component 24 therefore covers the opening of the housing 21 to prevent electrolyte leakage from the cavity. It should be noted that the shape and dimensions of the current collector component 24 are adapted to the housing 21 in this case to achieve a seal.

[0141] In some embodiments, the pole rod 25 mentioned above can be attached to the first connecting section 241 of the current collector component 24, wherein the pole rod 25 is electrically insulated from the first connecting section 241. In this case, the negative electrode tab can also be arranged at the end of the electrode assembly 22 that is closest to the opening; alternatively, the pole rod 25 mentioned above can be attached to the housing 21.

[0142] Consequently, the second connecting section 242 is welded to the entire circumference of the inside of the housing 21, significantly improving the reliability of the connection between the second connecting section 242 and the housing 21. Furthermore, this design allows the current collector component 24 to cover the opening of the housing 21, thus fulfilling a sealing function. This achieves a seal without the need for an additional end cap 23 to cover the opening, thereby simplifying the structure of the battery cell 20.

[0143] As in the Fig. 8 and Fig. As further shown in Figure 9, the current collector component 24 in some embodiments of the present application can comprise several second connection sections 242, wherein the several second connection sections 242 are spaced apart from each other along the circumferential direction of the inside of the housing 21.

[0144] The number of second connecting sections 242 can specifically be four, as in the Fig. 8 and Fig. 9 shown, or alternatively the number of second connecting sections 242 can be two, three, five, six, etc., which are not listed here in this embodiment.

[0145] In contrast to a configuration in which the current collector component 24 includes a second connection section 242, with several first weld sections 26 being formed between a second connection section 242 and the housing 21, the embodiment facilitates precise alignment of the weld point between the current collector component 24 and the inside of the housing 21 by having the current collector component 24 include several second connection sections 242.

[0146] According to some embodiments of the present application, in an implementation in which the current collector component 24 comprises several second connection sections 242, any two adjacent second connection sections 242 can be spaced apart at equal angular distances along the circumferential direction of the inside of the housing 21.

[0147] Thus, the multiple second connection sections 242 are evenly distributed around the central axis of the housing 21, which facilitates the machining of the current collector component 24.

[0148] According to some embodiments of the present application, in an implementation in which the current collector component 24 comprises several second connection sections 242 and any two adjacent second connection sections 242 are evenly distributed around the central axis of the housing 21, every second connection section 242 is welded to the inside of the housing 21 to form a first weld section 26.

[0149] In this embodiment, several first weld sections 26 are formed between the current collector component 24 and the housing 21, the number of first weld sections 26 being equal to the number of second connection sections 242. Since the several second connection sections 242 are evenly distributed around the central axis of the housing 21, several first weld sections 26 are spaced apart at substantially equal angular intervals along the circumferential direction of the inside of the housing 21.

[0150] This design ensures that the force of gravity exerted by the electrode assembly 22 on the current collector component 24, in combination with the weight of the current collector component 24 itself, acts evenly on several first weld sections 26. This reduces the probability of a weld crack at the first weld section 26 between the second connection section 242 and the housing 21 due to an uneven stress distribution, thereby further improving the reliability of the connection between the current collector component 24 and the housing 21.

[0151] According to some embodiments of the present application, the housing 21 comprises a circumferential side wall 211 and an end wall 212, wherein the inside of the circumferential side wall 211 forms the inside of the housing 21, while the end wall 212 faces the opening, wherein the thickness of the circumferential side wall 211 is a first thickness H1, the thickness of the second connecting section 242 is a second thickness H2, wherein 0.3 ≤ H1 / H2 ≤ 3.

[0152] As in Fig. As shown in Figure 6, the pole rod 25 can be specially insulated against the end wall 212 when the pole rod 25 is attached to the housing 21. It is understood that the first thickness H1 is too small and the second thickness H2 is too large if the ratio H1 / H2 of the first thickness H1 to the second thickness H2 is less than 0.3. Consequently, the circumferential side wall 211 becomes excessively thin. When the second connecting section 242 is welded to the circumferential side wall 211, this circumferential side wall 211 tends to laser perforation, thereby increasing the probability of electrolyte leakage into the battery 100. If the ratio H1 / H2 of the first thickness H1 to the second thickness H2 is greater than 3, the first thickness H1 is too large and the second thickness H2 is too small. Thus, the second connecting section 242 is too thin and exhibits low structural strength.If the battery cell 20 is exposed to a vibrating environment, the second connection section 242 may have difficulty withstanding the vibrations due to its low strength. This could lead to a weld crack between the second connection section 242 and the circumferential side wall 211, resulting in an unreliable connection between the second connection section 242 and the circumferential side wall 211.

[0153] For example, the value of H1 / H2 can be 0.3, 0.6, 1, 1.5, 1.8, 2, 2.6 or 3, without any limitation here.

[0154] In this embodiment, this configuration, by designing the ratio H1 / H2 of the first thickness H1 to the second thickness H2 such that it is greater than or equal to 0.3 and less than or equal to 3, firstly helps to prevent laser perforation due to the excessively thin circumferential side wall 211 of the housing 21 during welding, and reduces the risk of battery 100 leakage; secondly, it ensures that the second connection section 242 has high structural strength, making the weld between the second connection section 242 and the housing 21 tear-resistant even when the battery cell 20 is subjected to vibrations.

[0155] According to some embodiments of the present application, the ratio H1 / H2 of the first thickness H1 to the second thickness H2 can further be designed such that it is greater than or equal to 0.8 and less than or equal to 2.75.

[0156] Extensive experimental analyses carried out by the inventor of the present application have shown that the strength requirements of the second connection section 242 and the thickness requirements of the circumferential side wall 211 are better met when the ratio of the first thickness H1 to the second thickness H2 is 0.8 ≤ H1 / H2 ≤ 2.75. This further reduces the probability of the circumferential side wall 211 of the housing 21 being penetrated by the laser beam and simultaneously improves the reliability of the connection between the second connection section 242 and the circumferential side wall 211 of the housing 21.

[0157] For example, the value of H1 / H2 can be 0.8, 1.25, 1.6, 1.95, 2.4 or 2.75, without any limitation here.

[0158] In the above-mentioned embodiment, the first thickness H1 can be designed to be greater than or equal to 0.2 mm and less than or equal to 0.6 mm, while the second thickness H2 can be designed to be greater than or equal to 0.2 mm and less than or equal to 0.6 mm.

[0159] For example, specific values ​​for the first thickness H1 and the second thickness H2 can be looked up in Table 1, and Table 1 also illustrates the corresponding ratio H1 / H2 between the first thickness H1 and the second thickness H2.

[0160] In some embodiments, the value range for the first thickness H1 can be 0.3 mm to 0.55 mm if the value range of H1 / H2 is between 0.8 and 2.75, while the value range for the second thickness H2 can be 0.2 mm to 0.4 mm.

[0161] By defining 0.2 mm ≤ H1 ≤ 0.6 mm and 0.2 mm ≤ H2 ≤ 0.6 mm, it is ensured that the housing 21 and the second connection section 242 are not welded through during the welding process, thus guaranteeing the tightness of the battery.

[0162] According to some embodiments of the present application, the first connecting section 241 is circular, wherein the diameter R1 of the circular first connecting section 241 is greater than or equal to 15 mm and less than or equal to 100 mm. For example, the diameter R1 of the first connecting section 241 may be 15 mm, 30 mm, 50 mm, 75 mm or 100 mm, without limitation.

[0163] If the current collector component 24 is as in Fig. As shown in Figure 8, where the outer surface of the first connection section 241 is coplanar with the outer surface of the second connection section 242, this arrangement ensures that the outer surface of the first connection section 241 also rests against the inner surface of the housing 21. Consequently, the inner diameter R2 of the housing 21 is equal to the diameter R1 of the first connection section 241, allowing the first connection section 241 to fit into the housing 21. When the current collector component 24 is as shown in the Fig. 9 and Fig. Figure 10 shows that the outside of the first connecting section 241 is connected to the inside of the second connecting section 242 and the outside of the second connecting section 242 rests against the inside of the housing 21, the inside diameter R2 of the housing 21, the second thickness H2 and the diameter R1 of the first connecting section 241 satisfy the relationship: R1 + 2 × H2 = R2.

[0164] If the second connecting section 242 is located on one side of the plane in which the first connecting section 241 is located, the height H3 of the second connecting section 242 along the axial direction of the electrode assembly 22 is greater than or equal to 0.1 mm and less than or equal to 10 mm.

[0165] For example, the height h of the second connecting section 242 along the axial direction of the electrode assembly 22 can be 0.1 mm, 1 mm, 5 mm, 7 mm or 10 mm, but is not limited to these.

[0166] By designing the height h of the second connection section 242 along the axial direction of the electrode assembly 22 within the value range of 0.1 mm to 10 mm, the height of the second connection section 242 is suitable, which gives the second connection section 242 a high structural strength and at the same time avoids excessive space occupancy of the second connection section 242 in the vertical direction of the battery cell 20, thereby ensuring that the battery cell 20 has a high energy density.

[0167] According to some embodiments of the present application, the housing 21 comprises an opening end surface that surrounds the opening. The positional relationship between the aforementioned second connecting section 242 and the opening end surface of the housing 21 can be subdivided in several cases:

[0168] In the first case, as in Fig. As shown in Figure 10, the end face of the second connection section 242 facing away from the first connection section 241 is flush with the opening end face of the housing 21. In this example, the end cap 23 can additionally rest against the end face of the second connection section 242 facing away from the first connection section 241 if the battery cell 20 is provided with an end cap 23 and the end cap 23 is connected to the opening end face to seal the opening. This arrangement further improves the sealing performance of the end cap 23 over the opening.

[0169] In the second case, as in Fig. As shown in Figure 7, the end surface of the second connection section 242 facing away from the first connection section 241 is closer to the electrode assembly 22 than the opening end surface of the housing 21, wherein along the axial direction of the electrode assembly 22 the distance between the end surface of the second connection section 242 facing away from the first connection section 241 and the opening end surface of the housing 21 is L1, where 0 mm ≤ L1 ≤ 2 mm.

[0170] It should be noted that the end surface of the second connection section 242 facing away from the first connection section 241 can be either a flat surface or an inclined surface. For example, if the end surface of the second connection section 242 facing away from the first connection section 241 is an inclined surface, L1 denotes the minimum distance between the end surface of the second connection section 242 facing away from the first connection section 241 and the opening end surface. The reason for the end surface of the second connection section 242 facing away from the first connection section 241 being an inclined surface may also be due to machining or assembly errors of the current collector component 24.That is, if the machining accuracy of the current collector component 24 is low, resulting in poor flatness of the end surface of the second connection section 242 facing away from the first connection section 241, and this end surface forms an inclined surface, the minimum distance L1 measured between this end surface and the opening end surface is; Likewise, the minimum distance L1 measured between this end surface and the opening end surface is if the assembly accuracy of the current collector component 24 is low, causing this end surface to correspond to an inclined opening end surface.

[0171] In the first case, when installing the power collector component 24 inside the housing 21, the fact that the end face of the second connection section 242 facing away from the first connection section 241 is flush with the opening end face of the housing 21 indicates correct installation of the power collector component 24, which facilitates precise alignment of the installation position of the power collector component 24. In the second case, the design provides a gap between the end face of the second connection section 242 facing away from the first connection section 241 and the opening end face of the housing 21, which helps to prevent the second connection section 242 of the power collector component 24 from protruding beyond the housing 21.Furthermore, if the battery cell 20 is provided with an end cap 23 designed to overlap the opening end surface and cover the opening, this ensures that the end cap 23 first comes into contact with the opening end surface, thereby enabling a tight connection between the end cap 23 and the housing 21.

[0172] According to some embodiments of the present application, as in Fig. As further shown in Figure 7, the housing 21 has an opening and an opening end surface surrounding the opening, the battery cell 20 further comprising an end cap 23 covering the opening, the end cap 23 being welded to the opening end surface of the housing 21 to form a second weld section 28, wherein a distance is present along the axial direction Z of the electrode assembly 22 between the first weld section 26 and the second weld section 28.

[0173] The end cap 23 covers the opening to insulate the cavity inside the housing 21 from the external environment. The shape of the end cap 23 corresponds without restriction to the shape of the housing 21 in order to fit inside it. In this example, the pole rod 25 can be insulated against the end cap 23. In this configuration, both the positive electrode tab and the negative electrode tab are located at the end of the electrode assembly 22 facing the opening, which facilitates the connection of the negative electrode tab to the pole rod 25. Alternatively, the pole rod 25 can be insulated against other positions on the housing 21.

[0174] In some embodiments, the end cap 23 and the housing 21 can be welded together. During welding, parts of the end cap 23 and parts of the housing 21 are melted, with the molten parts forming the second weld section 28. The second weld section 28 can be formed, for example, by irradiating the current collector component 24 with ultrasonic waves or a laser beam. In the example of laser irradiation of the end cap 23 to form the second weld section 28, the projection direction of the laser is not restricted.

[0175] Fig. Figure 12 is a partially schematic view of the connection between the second connecting section 242 and the housing 21 of the battery cell 20 according to a further embodiment in an embodiment of the present application. In some embodiments, as in the Fig. 7 and Fig. As shown in Figure 12, the laser beam can be projected along the axial direction Z parallel to the electrode assembly 22 onto the end cap 23. After penetrating the end cap 23, the laser beam is projected onto the housing 21, causing parts of the end cap 23 and parts of the housing 21 to melt and form the second weld section 28.

[0176] Fig. 13 and Fig. Figures 14 are a partially schematic view of the connection between the second connecting section 242 and the housing 21 of the battery cell 20 according to a further embodiment in an embodiment of the present application. In further embodiments, as in the Fig. 13 and Fig. As shown in Figure 14, part of the end cap 23 overlaps the opening end surface of the housing 21. The laser beam can be emitted parallel to the opening end surface to melt the end cap 23 and the housing 21, thereby forming the second weld section 28, without the laser beam penetrating the end cap 23.

[0177] According to some embodiments of the present application, in which the end surface of the second connection section 242 facing away from the first connection section 241 is flush with the opening end surface of the housing 21 and the battery cell 20 is provided with an end cap 23, the laser beam can be projected inside the housing 21 along a direction perpendicular to the axial direction Z of the electrode assembly 22 onto the second connection section 242 to form the second weld section 28.

[0178] As in the Fig. 7, Fig. 12, Fig. 13 and Fig. As shown in Figure 14, in general, regardless of the method used to form the first weld section 26, the laser beam can be directed either along the axial direction Z of the electrode assembly 22 or parallel to the direction of the opening end face to form the second weld section 28. Furthermore, a distance exists along the axial direction Z of the electrode assembly 22 between the first weld section 26 and the second weld section 28, so that the first weld section 26 and the second weld section 28 do not come into contact.

[0179] In the above-mentioned embodiment, an exemplary assembly process for the battery cell 20 comprises: inserting the electrode assembly 22 into the cavity of the housing 21 through the opening; inserting the current collector component 24 into the cavity of the housing 21 through the opening; welding the second connecting section 242 to the housing 21 to form the first weld section 26; then overlapping the end cap 23 onto the opening end face to cover the opening, and welding the end cap 23 to the housing 21 to form the second weld section 28.

[0180] In the embodiment of the present application, the first welding section 26 and the second welding section 28 are designed such that a distance exists between them along the axial direction Z of the electrode assembly 22. This arrangement prevents the laser beam from being projected onto the first welding section 26 when the second welding section 28 is formed by laser melting of the end cap 23 and the housing 21, thus preventing the first welding section 26 from being affected by the second welding section 28.

[0181] According to some embodiments of the present application, as in Fig. As further shown in Figure 7, the housing 21 has an opening and an opening end surface surrounding the opening, the battery cell 20 further comprising an end cap 23 covering the opening, the end cap 23 being welded to the opening end surface of the housing 21 to seal the opening, the end cap 23 comprising a projection section 231 extending towards the interior of the housing 21, a gap being provided between the projection section 231 and the interior of the housing 21, and the second connecting section 242 being at least partially accommodated in the gap.

[0182] The formation of the leading section 231 can be achieved in various ways. For example, in the Fig. In the example shown in Figure 7, an annular groove is formed on the surface of the end cap 23 facing away from the interior of the housing 21. Corresponding to the annular groove, the end cap 23 includes a projecting section 231 that extends toward the interior of the housing 21. In this case, the projecting section 231 is annular. Alternatively, the projecting section 231 can be a block-like structure projecting from the surface of the end cap 23 facing away from the interior of the housing 21. Since at least part of the second connecting section 242 is located in the gap between the projecting section 231 and the interior of the housing 21, the projecting section 231 can restrict the displacement of the second connecting element 242 in a direction parallel to the opening end surface to a certain extent.

[0183] By arranging the protruding section 231 on the surface of the end cap 23, which faces the interior of the housing 21, the structural strength of the end cap 23 is increased, thereby improving the safety performance of the battery cell 20. If the second welding section 28 is configured such that the laser beam is emitted parallel to the opening end face to melt the end cap 23 and the housing 21, and if the laser beam is emitted again parallel to the opening end face after the end cap 23 has been attached to the housing 21, the protruding section 231 can obstruct the laser beam.

[0184] According to some embodiments of the present application, the positional relationship between the projection section 231 and the first connecting section 241 of the current collector component 24 can be subdivided in several cases when the end cap 23 is provided with a projection section 231:

[0185] In the first case, as in Fig. As shown in Figure 14, the distance between the projection section 231 and the first connecting section 241 along the axial direction of the electrode assembly 22 is L2, where 0 mm ≤ L2 ≤ 1 mm. In particular, L2 can be 0.2 mm, 0.5 mm, 0.7 mm, 0.8 mm or 1 mm, and the embodiment is not limited thereto.

[0186] It is understood that the end cap 23 and the first connecting section 241 effectively form an interference fit when L2 is less than 0 mm, with the protruding section 231 compressing the first connecting section 241. Under such compression, the current collector component 24 tends to deform, which may cause the first weld section 26, formed between the second connecting section 242 and the housing 21, to crack. When L2 is greater than 1 mm, the distance between the protruding section 231 and the first connecting section 241 is relatively large, creating a gap between them. This gap occupies space in the vertical direction of the battery cell 20, thereby reducing the capacity of the active material in the battery 100 and consequently affecting the energy density of the battery cell 20.

[0187] In the second case, as in Fig. As shown in Figure 7, the projection section 231 touches the side of the first connecting section 241 facing away from the electrode assembly 22.

[0188] As described above, in some embodiments the projecting section 231 can be in close contact with the first connecting section 241, without, however, exerting a force on the first connecting section 241 through the projecting section 231. Thus, there is no gap between the projecting section 231 and the first connecting section 241 that would occupy the interior space within the battery cell 20, and the projecting section 231 does not press against the first connecting section 241.

[0189] In the Fig. In the example shown in Figure 14, the gap between the projecting section 231 and the first connection section 241 L2 is small when 0 mm ≤ L2 ≤ 1 mm. This prevents excessive compression of the first connection section 241 by the projecting section 231, which would lead to a weld crack between the second connection section 242 and the housing 21. It also facilitates ensuring that the first fusion section 26, formed between the first connection section 241 and the housing 21, has high strength, thereby guaranteeing the connection stability between the current collector component 24 and the housing 21.At the same time, it is possible to minimize the space requirement of the gap in the vertical direction of the battery cell 20 without changing the overall height of the battery cell 20, then the capacity of the active material within the battery cell 20 is relatively high, thus ensuring a high energy density for the battery cell 20.

[0190] According to some embodiments of the present application, the base material of the housing 21 differs from the base material of the current collector component 24, wherein the melting point of the base material of the housing 21 is higher than the melting point of the base material of the current collector component 24.

[0191] Here, the base material of the housing 21 can refer to the material of the base layer 213 of the housing 21, while the base material of the current collector component 24 can refer to the material of the base layer 213 of the current collector component 24.

[0192] This design ensures that the melting point of the current collector component 24 is lower than the melting point of the housing 21. Consequently, when the current collector component 24 is welded to the inside of the housing 21 from the inside, the housing 21 is less susceptible to breakdown, thus effectively reducing the risk of electrolyte leakage from the housing 21.

[0193] According to some embodiments of the present application, based on the implementation in which the melting point of the base material of the housing 21 is greater than the melting point of the base material of the collector component 24, the coefficient of thermal expansion of the base material of the housing 21 can be smaller than the coefficient of thermal expansion of the base material of the collector component 24.

[0194] According to some embodiments of the present application, the base material of the housing 21 can, for example, be steel. In such a case, the base material of the current collector component 24 can, for example, be copper or aluminum.

[0195] It should be noted that the applicant's investigations have found that the main cause of the electrolyte leakage from battery 100 is the significant discrepancy between the coefficients of thermal expansion of the material of the current collector component 24 and the coefficients of thermal expansion of the material of the end cap 23, which makes the weld joint between the current collector component 24 and the end cap 23 susceptible to microcracks.

[0196] The applicant has innovatively designed the current collector component 24 to form a first weld section 26 with the inside of the housing 21. The weld penetration depth d1 formed by the first weld section 26 on the housing 21 is less than the thickness H1 of the housing 21, thus solving the problem of electrolyte leakage through microcracks at the weld point. Building on this, by designing the base material of the housing 21 as steel and the base material of the current collector component 24 as copper or aluminum, not only is the structural strength of the housing 21 increased, thereby improving the safety of the battery cell 20, but the manufacturing costs of the battery cell 20 are also reduced.

[0197] According to some embodiments of the present application, as in Fig. As further shown in Figure 14, a solder layer 27 is arranged on the surface of the housing 21 and / or the current collector component 24.

[0198] This means that the housing 21 can comprise a base layer 213 and a solder layer 27, with the solder layer 27 being located on the inner and outer surfaces of the base layer 213. In this configuration, the thickness H1 of the housing 21, the thickness H3 of the base layer 213, and the thickness H4 of the solder layer 27 satisfy the relationship: H1 = H3 + 2 × H4. The solder layer 27 can be formed by an electroplating process. The material of the solder layer 27 can be, for example, rosin, or it can be, for example, a nickel plating. The thickness of the solder layer 27 can be greater than or equal to 1 µm (micrometer) and less than or equal to 3 µm. Similarly, the current collector component 24 can also comprise a base layer 213 and a solder layer 27 with a structure corresponding to that of the housing 21, and this will not be repeated here.

[0199] The arrangement of the solder layer 27 facilitates improved welding results between the current collector component 24 and the housing 21.

[0200] According to some embodiments of the present application, as in Fig. As shown in Figure 14, the housing 21 comprises a base layer 213, wherein the solder layer 27 is arranged on the base layer 213 and part of the first weld section 26 is located within the base layer 213.

[0201] It is understood that during the welding of the second connection section 242 of the current collector component 24 with the housing 21, the laser beam can be directed along the axial direction Z perpendicular to the electrode assembly 22 towards the second connection section 242, provided that a solder layer 27 is arranged on both the housing 21 and the surface of the current collector component 24. The laser beam successively passes through the solder layer 27 on the inside of the second connection section 242, the base layer 213 of the current collector component 24, the solder layer 27 on the outside of the second connection section 242, and the solder layer 27 on the inside of the housing 21. The laser beam then reaches the base layer 213 of the housing 21 and forms a weld area in the base layer 213 of the housing 21 with a depth that is less than the thickness of the base layer 213 of the housing 21.

[0202] Given the small thickness of the solder layer 27, the design of the part of the first welding section 26 located within the base layer 213 allows the current collector component 24 to be welded to the base layer 213 of the housing 21, thereby improving the reliability of the connection between the current collector component 24 and the housing 21.

[0203] According to some embodiments of the present application, the first weld section 26 can also be configured such that it does not penetrate the base layer 213 of the housing 21.

[0204] Given the small thickness of the solder layer 27, the design of the first weld section 26, which does not penetrate the base layer 213 of the housing 21, further ensures that the first weld section 26 does not penetrate the housing 21. This reduces the probability of crack formation in the first weld section 26 and electrolyte leakage outside the housing 21.

[0205] According to some embodiments of the present application, as in Fig. As shown in 15, the manufacturing process of the battery cell 20 may in particular include the following steps: Step S101: Providing an electrode assembly 22, wherein the electrode assembly 22 has an electrode tab. Step S102: Provisioning a housing 21. Step S103: Provisioning a current collector component 24. Step S104: Connecting the current collector component 24 to the electrode tab, wherein the electrode assembly 22 and the current collector component 24 are housed in the casing 21. Step S105: The current collector component 24 is welded to the inside of the housing 21 to form a first weld section 26, wherein the weld penetration depth d1 of the first weld section 26 formed on the housing 21 is less than the thickness H1 of the housing 21.

[0206] It is understood that in the exemplary embodiment, the sequence of steps S101, S102, and S103 is not restricted. For example, steps S101, S102, and S103 can be performed sequentially.

[0207] According to some embodiments of the present application, step S104 can be implemented specifically by the following steps: Step 1: Connect the current collector component 24 to the electrode tab. Step 2: Placing the electrode assembly 22 connected to the current collector component 24 in the housing 21.

[0208] According to some other embodiments, step S104 can be implemented specifically by the following steps: Step 1: Placing the electrode assembly 22 in the housing 21. Step 2: Placing the current collector component 24 in the housing 21. Step 3: Connect the current collector component 24 to the electrode tab.

[0209] According to some embodiments of the present application, step S105 can be implemented as follows: For example, the laser beam can be emitted from inside the housing 21 along a direction perpendicular to the axial direction of the electrode assembly 22 to melt the housing 21 and the current collector component 24 and to form the first weld section 26; Alternatively, the laser beam can be emitted along a direction parallel to the axial direction of the electrode assembly 22 to melt the housing 21 and the current collector component 24 and to form the first weld section 26.

[0210] According to some embodiments of the present application, as in Fig. As shown in 16, the manufacturing process may further include the following: Step S201: Providing an end cap 23; Step S202: Welding the end cap 23 to the opening end surface of the housing 21 to form a second weld section 28, with a gap between the first weld section 26 and the second weld section 28 along the axial direction Z of the electrode assembly 22.

[0211] According to some embodiments of the present application, the above-mentioned step S202 of welding the end cap 23 to the opening end surface of the housing 21 to form a second weld section 28 can be implemented specifically using the following steps: Step 1: Overlap part of the end cap 23 onto the opening end surface of the housing 21. Step 2: Emitting a laser beam parallel to the opening end surface of the housing 21 to melt the end cap 23 and the housing 21, thereby forming the second weld section 28.

[0212] It goes without saying that the in Fig. 13 or Fig. 14 Battery cell 20 shown can be produced by the manufacturing process in this embodiment.

[0213] It should be noted that the relevant structure of the battery cell 20, which was manufactured according to the manufacturing process provided in the above-mentioned embodiments, can be found in the battery cells 20 provided in the above-mentioned embodiments and is not repeated here.

[0214] In a specific embodiment, as described in the Fig. 6 and Fig.As shown in Figure 7, the battery cell 20 comprises a housing 21, a current collector component 24, and an end cap 23. The housing 21 has an opening, and the end cap 23 covers the opening and is connected to the housing 21 to form an environment insulated from the outside of the battery cell 20. The electrode assembly 22 and the current collector component 24 are mounted inside the housing 21. The current collector component 24 comprises a first connection section 241 and a second connection section 242. The second connection section 242 is connected to the edge of the first connection section 241 and extends toward the opening. The second connection section 242 is welded to the housing 21 to form a first weld section 26.The weld penetration depth d1 of the first weld section 26 formed on the housing 21 is less than the thickness H1 of the housing 21, and the weld penetration depth d1 formed by the first weld section 26 on the housing 21 is greater than or equal to 0.05 mm and less than or equal to 0.3 mm.

[0215] The housing 21 has an opening end surface surrounding the opening, wherein the surface of the second connecting section 242 facing away from the first connecting section 241 is closer to the electrode assembly 22 than the opening end surface of the housing 21, wherein along the axial direction of the electrode assembly 22 the distance between the end surface of the second connecting section 242 facing away from the first connecting section 241 and the opening end surface of the housing 21 is L1, where 0 mm ≤ L1 ≤ 2 mm.

[0216] Finally, it should be noted that the above-mentioned embodiments serve only to illustrate the technical solutions of this application and are not intended to limit them. Although the present application has been described in detail with reference to the above-mentioned embodiments, it should be obvious to those skilled in the art that modifications can be made to the technical solutions described in the above-mentioned embodiments, or that some or all of the technical features therein can be replaced by equivalent substitute solutions. Such modifications or substitutions do not result in the corresponding technical solutions deviating from the scope of the technical solutions of the embodiments of the present application, and they should all fall within the scope of the claims and the description of the present application.In particular, the various technical features mentioned in the exemplary embodiments can be combined in any way, provided there is no structural conflict. This application is not limited to the specific exemplary embodiments disclosed herein, but encompasses all technical solutions that fall within the scope of the claims. Reference symbol list: 1000 vehicles; 100 batteries; 10 boxes; 11 First Section; 12 Second Section; 20 battery cells; 21 cases; 211 Perimeter side wall; 212 End wall; 213 Base layer; 22 Electrode assembly; 23 End cap; 231 Leading section; 24 Current collector component; 241 First connecting section; 242 Second connecting section; 25 Pole rod; 26 First welding section; 27 Solder layer; 28 Second welding section; 200 control; 300 engine.

Claims

Battery cell comprising: an electrode assembly having an electrode tab; a housing designed to receive the electrode assembly; and a current collector component housed in the housing and connected to the electrode tab; wherein the current collector component is welded to the inside of the housing to form a first weld section, wherein the weld penetration depth of the first weld section formed on the housing is less than the thickness of the housing. Battery cell according to claim 1, characterized in that the housing has an opening, wherein the electrode tab is located at an end of the electrode assembly that is near the opening. Battery cell according to claim 1 or 2, characterized in that the inside of the housing comprises a first surface and a second surface, wherein the first surface is arranged opposite the electrode assembly, the second surface is located on a side of the first surface near the opening of the housing, wherein an orthogonal projection of the first surface along an axial direction of the electrode assembly overlaps with an orthogonal projection of the second surface along an axial direction of the electrode assembly, and the first weld section is formed on the second surface. Battery cell according to one of claims 1 to 3, characterized in that the current collector component comprises a first connecting section and a second connecting section connected thereto, wherein the first connecting section is connected to the electrode tab, the second connecting section engages with the inside of the housing and the second connecting section is welded to the inside of the housing to form at least one first welded section. Battery cell according to claim 4, characterized in that the second connecting section is arranged on the outer edge of the first connecting section and the second connecting section is located on a side of the plane in which the first connecting section lies. Battery cell according to claim 5, characterized in that at least a part of the outside of the second connecting section abuts the inside of the housing, wherein the outside of the second connecting section is a surface that feeds the inside of the housing. Battery cell according to claim 6, characterized in that the outside of the second connecting section is completely in contact with the inside of the housing. Battery cell according to claim 4, characterized in that the first connecting section is a flat plate structure, wherein the outside of the second connecting section has a first projection on the plane in which the first connecting section lies, wherein the first projection overlaps with the outside of the first connecting section, wherein the outside of the first connecting section is a surface facing the inside of the housing. Battery cell according to claim 4, characterized in that the first weld section does not extend through the second connection section along the axial direction of the electrode assembly. Battery cell according to claim 4, characterized in that the second connecting section comprises a contact section and a guide section, wherein the contact section engages with the inside of the housing and at least one section of the contact section is welded to the inside of the housing, wherein one end of the guide section is connected to the contact section, the other end of the guide section is connected to the first connecting section, wherein the distance between the guide section and the inside of the housing gradually increases from one end to the other end of the guide section. Battery cell according to claim 10, characterized in that the first welding section along the axial direction of the electrode assembly does not pass through the contact section. Battery cell according to one of claims 4 to 11, characterized in that the second connecting section is firmly connected to the first connecting section via a connecting piece or the second connecting section and the first connecting section are formed as one manufactured part by an integral forming process. Battery cell according to one of claims 4 to 12, characterized in that the current collector component comprises only a second connecting section, wherein the second connecting section is an annular structure extending in the circumferential direction of the inside of the housing. Battery cell according to claim 13, characterized in that the second connecting section is welded to the inside of the housing to form several first weld sections, wherein the several first weld sections are spaced apart from each other along the circumferential direction of the inside of the housing. Battery cell according to claim 14, characterized in that at least two first weld sections of the several first weld sections are arranged symmetrically along the central axis of the housing. Battery cell according to claim 15, characterized in that any two adjacent first weld sections are spaced apart at equal angular intervals along the circumferential direction of the inside of the housing. Battery cell according to claim 13, characterized in that the second connecting section is welded to the inside of the housing to form a first welded section, wherein the first welded section is an annular structure extending along the circumferential direction of the inside of the housing, wherein the second connecting section is sealed to the housing. Battery cell according to one of claims 4 to 12, characterized in that the current collector component comprises several second connection sections, wherein the several second connection sections are spaced apart from each other along the circumferential direction of the inside of the housing. Battery cell according to claim 18, characterized in that any two adjacent second weld sections are spaced apart at equal angular intervals along the circumferential direction of the inside of the housing. Battery cell according to claim 18, characterized in that every second connection section is welded to the inside of the housing to form a first weld section. Battery cell according to one of claims 4 to 20, characterized in that the housing comprises a circumferential side wall, wherein the inside of the circumferential side wall forms the inside of the housing, wherein the thickness of the circumferential side wall is a first thickness H1, the thickness of the second connecting section is a second thickness H2, wherein 0.3 ≤ H1 / H2 ≤ 3. Battery cell according to claim 21, characterized in that 0.8 ≤ H1 / H2 ≤ 2.

75. Battery cell according to claim 21 or 22, characterized in that 0.2 mm ≤ H1 ≤ 0.6 mm and / or 0.2 mm ≤ H2 ≤ 0.6 mm. Battery cell according to one of claims 4 to 23, characterized in that the first connecting section is circular, wherein the diameter of the circular first connecting section is greater than or equal to 15 mm and less than or equal to 100 mm, and the height of the second connecting section along the axial direction of the electrode assembly is greater than or equal to 0.1 mm and less than or equal to 10 mm. Battery cell according to one of claims 4 to 24, characterized in that the housing has an opening and an opening end surface surrounding the opening, wherein the end surface of the second connecting section facing away from the first connecting section is flush with the opening end surface of the housing or the end surface of the second connecting section facing away from the first connecting section is closer to the electrode assembly than the opening end surface of the housing, wherein along the axial direction of the electrode assembly the distance between the end surface of the second connecting section facing away from the first connecting section and the opening end surface of the housing is L1, wherein 0 mm ≤ L1 ≤ 2 mm. Battery cell according to one of claims 1 to 25, characterized in that the housing has an opening and an opening end surface surrounding the opening, wherein the battery cell further comprises an end cap covering the opening, the end cap being welded to the opening end surface of the housing to form a second weld section, wherein a distance is present along the axial direction of the electrode assembly between the first weld section and the second weld section. Battery cell according to claim 26, characterized in that a part of the end cap overlaps the opening end surface of the housing, wherein the second welding section is formed by emitting a laser beam parallel to the opening end surface to fuse the end cap and the housing. Battery cell according to one of claims 4 to 27, characterized in that the housing has an opening and an opening end surface surrounding the opening, wherein the battery cell further comprises an end cap covering the opening, the end cap being welded to the opening end surface of the housing to seal the opening, wherein the end cap comprises a projection section that extends towards the interior of the housing, wherein a gap is provided between the projection section and the interior of the housing and the second connecting section is at least partially housed in the gap. Battery cell unit according to claim 28, characterized in that the projection section touches the surface of the first connecting section facing away from the electrode assembly or the distance between the projection section and the first projection section is L2 along the axial direction of the electrode assembly, wherein 0 mm ≤ L2 ≤ 1 mm. Battery cell according to one of claims 1 to 29, characterized in that the base material of the housing differs from the base material of the current collector component, wherein the melting point of the base material of the housing is higher than the melting point of the base material of the current collector component. Battery cell according to claim 30, characterized in that the coefficient of thermal expansion of the base material of the housing is smaller than the coefficient of thermal expansion of the base material of the current collector component. Battery cell according to claim 31, characterized in that the base material of the housing is steel, wherein the base material of the current collector component is copper or aluminum. Battery cell according to one of claims 1 to 32, characterized in that the surface of the housing and / or the current collector component is provided with a solder layer. Battery cell according to claim 33, characterized in that the housing comprises a base layer, wherein the solder layer is arranged on the base layer and part of the first welding section is located within the base layer. Battery cell according to claim 34, characterized in that the first welding section does not penetrate the base layer of the housing. Battery, comprising one of the battery cells according to any one of claims 1 to 35. Electrical device, wherein the electrical device comprises a battery according to claim 36. Battery cell, manufactured by a method comprising the steps of: providing an electrode assembly, wherein the electrode assembly has an electrode tab; providing a housing; providing a current collector component; connecting the current collector component to the electrode tab, wherein the electrode assembly and the current collector component are housed in the housing; and welding the current collector component to the inside of the housing to form a first weld section, wherein the weld penetration depth of the first weld section formed on the housing is less than the thickness of the housing. Battery cell according to claim 38, characterized in that the step of connecting the current collector component to the electrode tab, wherein the electrode assembly and the current collector component are housed in the housing, comprises: connecting the current collector component to the electrode tab, wherein the electrode assembly connected to the current collector component is housed in the housing; or arranging the electrode assembly in the housing, wherein the current collector component is housed in the housing and the current collector component is connected to the electrode tab. Battery cell according to claim 38 or 39, characterized in that the step of welding the current collector component to the inside of the housing to form a first weld section comprises: emitting a laser beam from inside the housing along a direction perpendicular to the axial direction of the electrode assembly to melt the housing and the current collector component and to form the first weld section; or emitting a laser beam along a direction parallel to the axial direction of the electrode assembly to melt the housing and the current collector component and to form the first weld section. Battery cell according to one of claims 38 to 40, characterized in that the manufacturing process, after welding the current collector component to the inside of the housing to form a first weld section, wherein the weld penetration depth of the first weld section formed on the housing is less than the thickness of the housing, further comprises the following steps: providing an end cap; and welding the end cap to the opening end face of the housing to form a second weld section, wherein there is a gap between the first weld section and the second weld section along the axial direction of the electrode assembly. Battery cell according to claim 41, characterized in that the step of welding the end cap to the opening end surface of the housing to form a second weld section further comprises the following steps: overlapping a portion of the end cap onto the opening end surface of the housing; and emitting a laser beam parallel to the opening end surface of the housing to melt the end cap and the housing, thereby forming the second weld section.

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