Battery cell, battery and electrical device

Abstract

Battery cell, including: an electrode assembly with a first arrester; a housing defining a receiving space and an opening located at one end of the receiving space, the receiving space being used to receive the electrode assembly; and a current-collecting end cover that is firmly connected to the housing, wherein the current-collecting end cover seals the opening in the housing and the current-collecting end cover is electrically connected to the first surge arrester.

Description

TECHNICAL AREA

[0001] The present application relates to the technical field of batteries and in particular to a battery cell, a battery and an electrical device. GENERAL STATE OF THE ART

[0002] Since energy conservation and emission reduction are key to the sustainable development of the automotive industry, electric vehicles have become an important part of this development due to their energy-saving and environmental benefits. Battery technology is another important factor influencing the development of electric vehicles.

[0003] In some cases, a battery is electrically connected to an electrode assembly using a current collector to draw off electrical energy and transfer it to an electrical device, but the arrangement of the current collector within the battery casing inevitably takes up space within the casing, which in turn adversely affects the battery's capacity. SUMMARY OF THE INVENTION

[0004] The present application aims to solve at least one of the prior art technical problems. To this end, one objective of the present application is to propose a battery cell, a battery, and an electrical device to improve the utilization of the interior space of the battery housing.

[0005] An embodiment of a first aspect of the present application provides a battery cell, wherein the battery cell comprises an electrode assembly, a housing, and a current-collecting end cap. The electrode assembly has a first current collector, the housing defines a receiving space and an opening located at one end of the receiving space, the receiving space being used to receive the electrode assembly, and the current-collecting end cap is fixedly connected to the housing, the current-collecting end cap sealingly covers the opening of the housing, and the current-collecting end cap is electrically connected to the first current collector.

[0006] In this embodiment, the current-collecting end cap, by being electrically connected to the first conductor and fixedly connected to the housing to seal the opening of the housing, can act both as a current-collecting element and as a sealing end cap, thus fulfilling the roles of current collection and sealing. This reduces the number of parts and the welding process, thereby simplifying the structure of the battery cell and increasing the space utilization rate in the housing, thus reducing the internal resistance of the battery cell.

[0007] In some embodiments, the current-collecting end cap is welded to the housing, creating a conductive connection between the two. Welding allows for a conductive, sealed connection between the current-collecting end cap and the housing, facilitating electrode routing and sealing of the battery cell housing, thus simplifying the battery structure.

[0008] In some embodiments, the housing comprises a main body section and a welded section, wherein the main body section surrounds an outer surface of the electrode assembly and the welded section is located at one end of the main body section near the opening. The current-collecting end cap is welded to the welded section to form a first fusion section. By welding and fusing the current-collecting end cap to the welded section near an opening end of the housing to form the first fusion section, the internal resistance can be reduced while a sealed connection is achieved to create a conductive link, thereby simplifying the structure of the battery end cap.

[0009] In some embodiments, the current-collecting end cap includes a first connection section and a second connection section, wherein the first connection section is electrically connected to the first current collector; and the second connection section is connected to the first connection section and welded to the weld section of the housing to form the first fusion connection section. Welding to the first current collector and the housing through the first connection section and the second connection section, respectively, can effectively separate the weld positions of the current-collecting end cap with the first current collector and the weld positions of the current-collecting end cap with the housing to avoid adverse effects from mutual interference during laser welding, thus contributing to a reduction in the internal resistance of the battery cell.

[0010] In some embodiments, the second connection section encloses an outer edge of the first connection section and projects in a direction away from the electrode assembly. The non-coplanar configuration of the first and second connection sections allows the positions where the first fusible link section, formed by welding to the current-collecting end cap, connects to the first conductor to be arranged separately in different orientations, thus preventing mutual interference during welding.

[0011] In some embodiments, an end face on a side of the second connecting section, which is away from the first connecting section, is flush with an end face on a side of the welded section, which is away from the main body section, so that the second connecting section and the welded section form the first fusion connecting section by butt welding at the flush end faces.During butt welding, there is sufficient space for the laser to be positioned outside the battery, which contributes to improving the precision of the laser welding and thus the weld quality; at the same time, the first fusion section formed by butt welding is located on the end faces of the second connection section and the weld section, which can reduce the length of the second connection section that is fitted to the weld section in the axial direction of the electrode assembly, thereby reducing the amount of the occupied interior space of the battery housing.

[0012] In some embodiments, the first fusion section is configured such that a laser penetrates the second fusion section in a direction that intersects an axis of the electrode assembly, at least partially melting the weld section to form the first fusion section. When welding using the internal welding process, the laser's emission direction is directed outside the battery, which can prevent damage to the electrodes from the laser emitted onto the electrode assembly during welding, thereby improving the safety of the welding process.

[0013] In some embodiments, the first fusion section does not penetrate the weld section. The laser welding parameters can be controlled during welding so that the first fusion section does not penetrate the weld section. This helps to avoid cracks in the first fusion section formed by the welding process, which in turn affects the structural strength and sealing performance of the battery.

[0014] In some embodiments, the second connection section has a thickness of t1 in a direction perpendicular to a central axis of the electrode assembly, and the second connection section has a height of h0 in an axial direction of the electrode assembly, where t1 and h0 satisfy the following: 2 ≤ h0 / t1 ≤ 6. A reasonable selection of the size of the second connection section can better balance the laser welding requirement for the size of the second connection section along the axial direction of the electrode assembly and the energy density of the battery cell.

[0015] In some embodiments, the second connecting section has a thickness of t1 in a direction perpendicular to a central axis of the electrode assembly, where t1 satisfies the following: 0.1 mm ≤ t1 ≤ 0.5 mm. By selecting a suitable thickness for the second connecting section, the strength and overcurrent capability of the current-collecting end cap 23 can be balanced.

[0016] In some embodiments, an outer surface of the second connection section is in an interference fit with an inner surface of the welding section. By ensuring that the second connection section and the housing are in an interference fit, there is no gap between the outer surface of the second connection section of the current-collecting end cap and the inner surface of the housing. This allows the current-collecting end cap and the housing to be firmly connected, making the connection reliable. At the same time, this mitigates the risk of faulty welding and leakage due to an excessive gap, as well as damage to the electrode assembly from the exiting laser during welding, thus contributing to weld quality.

[0017] In some embodiments, the second connection section comprises a plurality of first projecting sections provided at intervals and projecting in a direction away from the electrode assembly, and second projecting sections located between two adjacent first projecting sections, the height of the second projecting sections being less than that of the first projecting sections in the axial direction of the electrode assembly; and the first projecting sections and the second projecting sections being separately welded to the weld section to form portions of the first fusion connection section. This design can allow the first projecting section to exhibit some deformability during assembly, which better balances the structural strength of the current-collecting end cap and the feasibility of assembly and positioning.

[0018] In some embodiments, a plurality of second projecting sections are evenly distributed around a central axis of the electrode assembly. The first fusible link section formed between the current-collecting end cap and the housing maintains a symmetrical structure, which can improve the impact resistance of the weld, thereby preventing weld breakage due to uneven force upon impact from an external force.

[0019] In some embodiments, the inner diameter of the main body section is smaller than the inner diameter of the welded section, creating a stepped surface at the junction of an inner surface of the main body section and an inner surface of the welded section. The current-collecting end cap rests against this stepped surface. The difference in the inner diameters of the main body section and the welded section results in the formation of a stepped surface at their junction, and the current-collecting end cap can be positioned using this stepped surface. This allows for more convenient butt joint positioning, thus improving assembly efficiency.

[0020] In some embodiments, the wall thickness of the main body section is equal to the wall thickness of the welded section. This makes it possible to maintain the strength of the housing while creating a stepped section for better positioning of the current-collecting end cap.

[0021] In some embodiments, an outer surface of the main body section is coplanar with an outer surface of the welded section. This coplanarity of the outer surface of the main body section with the outer surface of the welded section can maintain consistency in the dimensions of the outer surfaces of the battery cells, thus facilitating the combined assembly of a large number of battery cells.

[0022] In some embodiments, the difference between the inner diameter of the welded section and the inner diameter of the main body section is greater than or equal to 0.1 mm. The stepped surface of a specific width formed between the welded section and the main body section can provide better positioning for mounting the current-collecting end cap, thereby improving assembly efficiency.

[0023] In some embodiments, the housing further includes a curved section, wherein the curved section is connected to an end of the welded section that is furthest from the main body section and is bent towards an inside of the welded section to form a gap between the curved section and the welded section, with at least a portion of the second connecting section being located within the gap. Providing the curved section limits displacement of the current-collecting end cap to prevent it from detaching from the housing, thereby ensuring a reliable connection between the current-collecting end cap and the housing.

[0024] In some embodiments, the battery cell further includes a sealing ring, wherein the sealing ring is located within the gap and is at least partially clamped between the second connecting section and the bent section. Providing a sealing ring can further improve the sealing performance of the battery cell, which helps to prevent electrolyte leakage.

[0025] In some embodiments, the curved section includes a connecting edge and an annular edge, the annular edge being connected to the welded section of the housing via the connecting edge, with one end of the annular edge furthest from the connecting edge being near the electrode assembly; and the sealing ring comprising a first sealing body and a second sealing body connected together, the first sealing body being clamped between the second connecting section and the annular edge, and the second sealing body being clamped between one side of the second connecting section facing away from the electrode assembly and the connecting edge. The structural design of the sealing ring allows the second connecting section to achieve a sealed fit with both the annular edge and the connecting edge, resulting in improved sealing performance.

[0026] In some embodiments, the first sealing element comprises a first surface facing the second connecting section and a second surface facing the annular edge, wherein at least one of the first surface and the second surface is provided with a third projecting section. The third projecting section further improves the sealing performance of the surface fit, helping to prevent electrolyte leakage from the gap between the current-collecting end cap and the housing.

[0027] In some embodiments, the third projecting section has a width of a along an axial direction of the electrode assembly and a height of b along a direction perpendicular to the axial direction of the electrode assembly, where a and b satisfy the following: 0.5 mm ≤ a ≤ 2 mm, and 0.2 mm ≤ b ≤ 0.5 mm. By reasonably selecting the size of the third projecting section, the clamping action of the first sealing element on the second connecting section and the annular edge can be improved, and thus the sealing action of the first sealing element can be enhanced.

[0028] In some embodiments, the first connection section is welded to the first conductor to form the second fusible link section. Forming the second fusible link section by welding allows the current-collecting end cap to be permanently connected to the electrode assembly, thus improving the overall strength of the battery and ensuring a stable conductive connection between the current-collecting end cap and the electrode assembly, even under the impact of an external force.

[0029] In some embodiments, the first connecting section comprises a first side surface facing the electrode assembly and a second side surface facing away from the electrode assembly, wherein at least one of the first side surface and the second side surface is provided with at least one reinforcing rib projecting from a surface on which it is located, the reinforcing rib being used to strengthen the current-collecting end cap. The first connecting section of the current-collecting end cap, which is provided with a reinforcing rib projecting from a plane in which it is located, can improve the deformation resistance of the current-collecting end cap.

[0030] In some embodiments, at least a portion of the reinforcing rib located on the first side face is welded to the first current collector to form the second fusion section. The reinforcing rib can rest against the first current collector when the current-collecting end cap is aligned with the electrode assembly, and welding the reinforcing rib to the first current collector can reduce weld defects caused by the gap between the two, thus improving the weld quality of the second fusion section and simultaneously increasing the structural strength of the current-collecting end cap.

[0031] In some embodiments, the reinforcing rib for forming the second fusion section is a stamped groove, with one side of the stamped groove recessed into a second side face of the first fusion section opposite the electrode assembly. Producing a stamped groove as a reinforcing rib on the first fusion section by stamping is a simple and cost-effective process and does not increase the weight of the current-collecting end cap. Furthermore, the recess on the side opposite the electrode assembly can also be used to indicate a welding position for forming the second fusion section, thus simplifying welding positioning.

[0032] In some embodiments, the second fusible link section is arranged at uniform intervals along a circumferential direction around the center of the first link section. The electrical energy of the electrode assembly can be transferred uniformly to all parts of the current-collecting end cap, further improving the uniformity of the electrical energy transfer. This helps to prevent the flow of excessive electrical energy through partial positions of the current-collecting end cap.

[0033] In some embodiments, the second fusible link section is characterized by a multitude of radially extending spoke-like patterns or a multitude of crescent-shaped patterns. The design of the pattern of the second fusible link section allows the current to be directed to a position of the current-collecting end cap near the central area and to an edge of the current-collecting end cap near the inner surface of the housing, thus enabling the current-collecting end cap to conduct electrical energy uniformly.

[0034] In some embodiments, the first connection section includes a surge arrester connection section and a pressure relief section, wherein the surge arrester connection section is welded to the first arrester to form a second fusible link section, and the pressure relief section is configured to relieve internal pressure of the battery cell when the internal pressure or temperature of the battery cell reaches a threshold. By design, the pressure relief mechanism can, when the internal pressure of the battery cell reaches the threshold, perform its pressure relief function to reduce fire, explosion, and other safety hazards that can easily occur during the use of the battery cell.

[0035] In some embodiments, the current collector connection section surrounds an outer surface of the pressure relief section. In this way, the current from the electrode plate flows through the second connection section, the first fusible link section, and the housing after passing through the second fusible link section, without having to pass through the pressure relief section, which has a non-uniform thickness, thus reducing the effect of the pressure relief section on the internal resistance.

[0036] In some embodiments, the drain connection section and the pressure relief section are provided in a single-piece molded form. This can reduce the welding required between the pressure relief section and the drain connection section, thus avoiding mutual interference between the welding processes of the two and saving labor hours, thereby improving production efficiency.

[0037] In some embodiments, the pressure relief section includes a grooved slot configured to tear along the groove to release the internal pressure of the battery cell when the internal pressure or temperature of the battery cell reaches a threshold. Pressure relief is facilitated by providing grooved slots on the surface, eliminating unnecessary welds without adding weight or space to the battery.

[0038] In some embodiments, the grooved slot is located on a surface of the first connecting element facing the electrode assembly. In this embodiment, the grooved slot is located on the first side face of the first connecting element facing the electrode assembly, so that the grooved slot is located inside the battery cell, which helps to prevent failure of the pressure relief function due to oxidation or corrosion.

[0039] In some embodiments, the grooved groove is an annular groove centered in the middle of the first connecting section. A grooved groove with a regular pattern can prevent inconsistent pressure drop across the groove, which is more conducive to setting and controlling the pressure or temperature threshold for pressure relief.

[0040] In some embodiments, the central angle Έ corresponding to the grooved groove has a value range of: 270° ≤ Έ ≤ 330°. By selecting a suitable central angle, it can be better adapted to the material and thickness of the current-collecting end cap as well as the set pressure relief threshold, thereby better meeting the pressure relief requirements.

[0041] In some embodiments, the first connection section further includes a central area, wherein the central area is a projection area of ​​a central hole of the electrode assembly onto the first connection section; and the grooved slot is located on the circumference of the central area. The grooved slot in the pressure relief section is located on the circumference of the central area and on the inside of the drain connection section, thereby avoiding the drain connection section and the central hole, thus better ensuring the implementation of the pressure relief function.

[0042] In some embodiments, the central area is a circular area and the grooved groove is an annular groove centered in the middle of the first connecting section, wherein the central area has a diameter of d1; and the grooved groove has a minimum diameter of d2, wherein d2 / d1 ≤ 4. Limiting the minimum diameter of the grooved groove to be larger than the diameter of the central area can ensure that the grooved groove is located outside the central area, so that if an anomalous condition occurs within the electrode assembly and gas is generated, it is easier to converge through the central hole and exert pressure on the grooved groove on the end cap to cause the grooved groove to rupture and release the pressure when the preset condition is met.

[0043] In some embodiments, the current collector connection section is provided with at least one stamped groove that is welded to the first current collector to form the second fusible link section, with the grooved groove located between the current collector connection section and the central area. The arrangement of the grooved groove between the current collector connection section and the central area can mitigate any adverse effects on the current-collecting effect of the current-collecting end cap and also facilitate the implementation of the pressure relief function of the grooved groove.

[0044] In some embodiments, the first joining section is circular, a circle containing an endpoint of the second fusion joining section that is furthest from the center of the first joining section has a diameter of d3, and the first joining section has a diameter of d4, where d3 < d4. The maximum diameter of the second fusion joining section being smaller than the diameter of the first joining section allows the position of the second fusion joining section to be spaced away from the housing and the first fusion joining section, thus avoiding impairment of weld quality due to mutual influence during welding.

[0045] In some embodiments, the central area is a circular area centered in the middle of the first connecting section, and the grooved groove is an annular groove centered in the middle of the first connecting section, and the central area has a diameter of d1; the grooved groove has a diameter of d2, the fusion connecting area has an outer diameter of d3, and the first connecting section has a diameter of d4, which satisfy: 0.8≤d42−d32d22−d12≤1.2. If the dimensions of the current-collecting end cap meet this condition, the internal resistance of the battery is low.

[0046] In some embodiments, the current collector connection section of the first connection section has a minimum thickness of t2 along an axial direction of the electrode assembly, a material of the current collector end cap has a modulus of elasticity of E, and the electrode assembly has a weight of W, wherein t2 × E / W ≥ 7000mm -1 By adjusting the above parameters of the current-collecting end cover, the load-bearing capacity of the current-collecting end cover can be ensured, which can suppress deformation or even breakage under the gravity of the electrode assembly.

[0047] In some embodiments, at least one of two opposing surfaces of the current-collecting end cap and the housing is provided with a paste mask layer. Providing a paste mask layer on the weld surface can contribute to improved weld quality.

[0048] In some embodiments, the material of the first material layer is copper, the material of the second material layer is carbon steel, and the material of the paste mask layer is nickel. Selecting copper with high conductivity for the current-collecting end cap can improve current collection and thus reduce the battery's internal resistance. Selecting carbon steel for the casing can balance structural strength and conductivity. Using nickel as the paste mask layer can improve the quality of the weld and thus help prevent cracking.

[0049] In some embodiments, a surface of the current-collecting end cap is provided with a first paste mask layer, and a surface of the housing is provided with a second paste mask layer, wherein the first paste mask layer has a thickness of u1 and the second paste mask layer has a thickness of u2, where 1 µm ≤ u1 + u2 ≤ 9 µm. By reasonably adjusting the thickness of the paste mask layers, it is possible to control the weight of the end cap and the housing while simultaneously supporting the welding process, thereby reducing unnecessary weight loss.

[0050] In some embodiments, the electrode assembly further includes a second arrester with a polarity different from that of the first arrester; and wherein the battery cell further includes electrode terminals, the electrode terminals being located at an end of the housing away from the opening and electrically connected to the second arrester.

[0051] Embodiments of a second aspect of the present application provide a battery which includes the battery cell in the embodiments described above.

[0052] Embodiments of a third aspect of the present application provide an electrical device which includes the battery in the embodiments described above, wherein the battery is used to provide electrical energy.

[0053] The above description is only a summary of the technical solutions of the present application. To better understand the technical means of the present application, the technical means can be implemented according to the content of the description. To make the above-mentioned and other objectives, features, and advantages of the present application more understandable, specific implementations of the present application are explained below by way of example. DRAWING DESCRIPTION

[0054] In the drawings, unless otherwise specified, identical reference numerals denote identical or similar parts or elements in multiple drawings. These drawings are not necessarily drawn to scale. It should be understood that these accompanying drawings represent only some implementations disclosed under the present application and should not be considered as limiting the scope of protection of the present application. Fig. Figure 1 shows a schematic structural representation of a vehicle that is provided in some embodiments of the present application; Fig. Figure 2 shows a schematic exploded view of a battery provided in some embodiments of the present application; Fig. Figure 3 shows a schematic structural representation of a battery cell, which is provided in some embodiments of the present application; Fig. 4 shows a main view of the in Fig. 3 battery cells shown; Fig. Figure 5 shows a schematic cross-sectional view of the battery cell in some embodiments, which are described in Fig. 4 are shown, along the direction AA; Fig. Figure 6 shows a partially enlarged view at B in Fig. 5; Fig. Figure 7 shows a schematic cross-sectional view of a battery cell, which in some other embodiments of the present application is provided along the AA direction; Fig. Figure 8 shows a schematic structural representation of a current-collecting end cover in some embodiments of the present application; Fig. Figure 9 shows a partially enlarged view at C in Fig. 7; Fig. Figure 10 shows a partially enlarged view at C in Fig. 7 in some other embodiments. Fig. Figure 11 shows a schematic cross-sectional representation of a battery cell, which in some further embodiments of the present application is provided along the AA direction; Fig. Figure 12 shows a partially enlarged view at D in Fig. 11; Fig. Figure 13 shows a schematic structural representation of a sealing ring provided in some embodiments of the present application; Fig. Figure 14 shows a schematic structural representation of a current-collecting end cap connected to a first surge arrester provided in some embodiments of the present application; Fig. Figure 15 shows a schematic structural representation of a current-collecting end cap connected to a first surge arrester provided in some other embodiments of the present application; Fig. Figure 16 shows a schematic cross-sectional view of a current-collecting end cap provided in some embodiments of the present application; Fig. Figure 17 shows a schematic structural representation of a current-collecting end cap, which is provided in some further embodiments of the present application; and Fig. Figure 18 shows a schematic cross-sectional view of a current-collecting end cap, which is provided in some further embodiments of the present application. Description of the reference symbols:

[0055] Vehicle 1000; Battery 100, control unit 200, motor 300; Box body 10, first section 11, second section 12; Battery cell 20, housing 21, end wall 211, curved section 212, connecting edge 2121, annular edge 2122, main body section 213, weld section 214, second paste mask layer 215, first paste mask layer 235, electrode assembly 22, current collector 221, first current collector 221A, second current collector 221B, central hole 222, current-collecting end cap 23, reinforcing rib 231, first connecting section 232, current collector connecting section 2321, pressure relief section 2322, grooved groove 2323, central area 2324, second connecting section 233, first projecting section 2331, second projecting section 2332, electrode terminal 24, second fusion connection section 25, first fusion connection section 26, sealing ring 27, first sealing body 271, second sealing body 272, third preceding section 273. DETAILED DESCRIPTION

[0056] Embodiments of the technical solutions of the present application are described in detail below with reference to the drawings. The following embodiments are used only to illustrate the technical solution of the present application more clearly and are therefore used only as examples and cannot be used to limit the scope of protection of the present application.

[0057] 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 here serve only to describe specific embodiments and are not intended to limit the present application. The terms "comprising" and "having" and any variations thereof in the description and claims of the present application and in the above description of the drawings are intended to cover a non-exclusive inclusion.

[0058] In the description of embodiments of the present application, the technical terms "first", "second", and the like are used only to distinguish between different objects and are not to be understood as indicating or suggesting a relative importance or implicitly indicating the quantity, specific order, or primary and secondary relationship of the specified technical features. In the description of embodiments of the present application, the meaning of "a plurality of" is two or more, unless expressly and specifically defined otherwise.

[0059] The reference to an “embodiment” here means that a particular feature, structure, or property described in connection with the embodiment may be included in at least one embodiment of the present application. The appearance of this phrase in different places in the description does not necessarily refer to the same embodiment, nor does it imply a separate or alternative embodiment that is mutually exclusive with other embodiments. It is understood explicitly and implicitly by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0060] In the description of the embodiments of the present application, the term "and / or" is merely an associative relationship used to describe associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, both A and B exist, and B exists alone. Additionally, the symbol " / " here generally means that the objects associated with it are in an "or" relationship before and after it.

[0061] In the description of the embodiments of the present application, the term ‘a plurality of’ refers to two or more (including two), and similarly ‘a plurality of groups’ refers to two or more (including two) groups, and ‘a plurality of sheets’ refers to two or more (including two) sheets.

[0062] In the descriptions of the embodiments of the present application, orientations or positional relationships indicated by the technical terms "middle", "longitudinal", "transverse", "length", "width", "thickness", "top", "bottom", "front", "back", "left", "right", "vertical", "horizontal", "above", "below", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are orientations or positional relationships as shown in the drawings and serve only the purpose of facilitating and simplifying the descriptions of the embodiments of the present application, rather than indicating or suggesting that specified devices or elements have certain orientations and must be designed and operated in those certain orientations, so that these terms are not to be interpreted as limiting the embodiments of the present application.

[0063] In the description of the embodiments of the present application, unless expressly stated otherwise and limited, the technical terms "assemble", "connect", "attach", "fasten", and the like should be understood in a broad sense, such as a fixed connection, a detachable connection, or a one-piece connection; a mechanical connection or an electrical connection; a direct connection, an indirect connection through an intermediate medium, an internal connection between two elements, or an interaction between two elements. Those skilled in the art in this field will be able to understand the specific meanings of the above terms in the embodiments of the present application depending on the specific situations.

[0064] In a general battery cell, the electrode assembly must be electrically connected to the casing so that the casing can be used as an electrode terminal for input or output of electrical energy. To conveniently connect the casing to the electrode assembly within the battery cell, a current collector is also provided within the battery cell casing. The current collector is located on the side of the electrode assembly facing an end cap of the battery cell. The electrode assembly is electrically connected to the end cap via the current collector, and the end cap covers the opening in the casing and is electrically connected to the casing. In this way, the electrode assembly, the current collector, the end cap, and the casing are connected sequentially to form a conductive path.

[0065] In this embodiment, an example assembly process of the battery cell is essentially as follows: An electrode assembly is placed in the housing, and a current collector is placed in the housing and on one side of the electrode assembly; a laser penetrates the current collector from the side of the current collector opposite the electrode assembly in an extension direction of the central axis of the electrode assembly, so that the current collector is welded to the electrode assembly's conductors; an end cap is placed to cover the housing opening; and a laser penetrates the end cap from outside the housing in the extension direction of the central axis of the electrode assembly, so that the end cap is welded to the current-collecting end cap.

[0066] Through careful investigation, the inventors discovered that welding the current collector to the terminals and the housing often requires leaving sufficient space for the weld joint at the end of the battery housing and simultaneously providing an end cap to seal the housing opening, thus preventing electrolyte leakage. Consequently, during battery assembly, the current collector must be welded first, followed by the end cap and the housing. This not only requires more labor hours but also necessitates allocating more welding space within the structure, which in turn reduces the battery's capacity to accommodate the electrode assembly.

[0067] To address this technical problem, the inventors conceived the idea of ​​using the current collector as an end cap. By electrically connecting the current collector separately to the terminals and the housing to conduct the current from the terminals to the housing while simultaneously sealing the housing opening, the two parts, the current collector and the end cap, can be replaced by a single current-collecting end cap. This reduces assembly labor hours and simplifies the battery structure without requiring large welding dimensions that would compromise the electrode receiving space.

[0068] Based on such an improvement idea, embodiments of the present application provide a battery cell comprising an electrode assembly, a housing and a current-collecting end cover, wherein the electrode assembly has current collectors, the housing is used to receive the electrode assembly and the current-collecting end cover is housed in the housing and the current-collecting end cover is conductively connected to the current collectors and seals an opening of the housing.

[0069] The battery cells disclosed in the embodiments of the present application can be used in an electrical device such as a vehicle, a ship, or an aircraft, but are not limited to such use. A battery cell, battery, or the like comprising the battery disclosed in the present application can be used to form a power supply system for such an electrical device.

[0070] Embodiments of the present application provide an electrical device that uses a battery as a power source, and the electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery-powered vehicle, an electric vehicle, a ship, a spacecraft, and so on. The electric toy may include stationary or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, and electric aircraft toys. The spacecraft may include aircraft, rockets, space shuttles, spacecraft, and the like.

[0071] To simplify the description in the following embodiments, an electrical device, which is a vehicle 1000 according to an embodiment of the present application, is taken as an example for the description.

[0072] With reference to Fig. 1 is Fig. 1 A schematic structural representation of a vehicle 1000 according to some embodiments of the present application. The vehicle 1000 can be a fuel-powered vehicle, a gas-powered vehicle, or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, an extended-range electric vehicle, or the like. The vehicle 1000 is provided internally with a battery 100, and the battery 100 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 be used as the operating voltage supply for the vehicle 1000. The vehicle 1000 can further include a control unit 200 and a motor 300.The control unit 200 is used to control the battery 100 to supply power to the motor 300, for example to meet the power requirements during starting, navigation and driving of the vehicle 1000.

[0073] In some embodiments of the present application, the battery 100 can not only serve as the operating energy source of the vehicle 1000, but also as the propulsion energy source of the vehicle 1000, thereby replacing or partially replacing fuel or natural gas to provide propulsion power for the vehicle 1000.

[0074] Referring to Fig. 2. Fig. Figure 2 shows a schematic cross-sectional view of a battery 100, which is provided in some embodiments of the present application. The battery 100 comprises a box body 10 and battery cells 20, wherein the battery cells 20 are housed within the box body 10, the box body 10 being used to provide a receiving space for the battery cells 20, and the box body 10 being able to have different structures. In some embodiments, the box body 10 may comprise a first section 11 and a second section 12, wherein the first section 11 and the second section 12 cover each other and the first section 11 and the second section 12 together define the receiving space for receiving the battery cells 20.The second part 12 can have a hollow structure with an opening at one end, and the first part 11 can have a plate-like structure, with the first part 11 covering the opening side of the second part 12, so that the first part 11 and the second part 12 together define the receiving space; and the first part 11 and the second part 12 can each have a hollow structure with an opening at one end, with the opening side of the first part 11 resting on the opening side of the second part 12. Naturally, the box body 10 formed by the first section 11 and the second section 12 can have a variety of shapes, such as a cylinder, a cuboid, or the like.

[0075] The battery 100 can contain a plurality of battery cells 20, and the plurality of battery cells 20 can be connected in series, parallel, or in a mixed circuit, where the mixed circuit means that the plurality of battery cells 20 are connected both in series and in parallel. The plurality of battery cells 20 can be directly connected to one another in series, parallel, or in a mixed circuit, and then the whole consisting of the plurality of battery cells 20 can be housed in the box body 10; and of course, the battery 100 can also be in the form of a battery module, which is first formed by the plurality of battery cells 20 connected in series, parallel, or in a mixed circuit, then several battery modules can be connected in series, parallel, or in a mixed circuit to form a whole, and housed in the box body 10.The battery 100 may also include other structures; for example, the battery 100 may also include a bus component for realizing electrical connections between the multitude of battery cells 20.

[0076] Each battery cell 20 can be a secondary battery or a primary battery; or it can be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cells 20 can be cylindrical, flat, rectangular, or in other shapes.

[0077] The specific structure of battery cell 20 is described in detail below in conjunction with the accompanying drawings.

[0078] Fig. Figure 3 shows a schematic structural representation of a battery cell, which is provided in some embodiments of the present application, Fig. 4 shows a main view of the in Fig. 3 battery cells shown, Fig. Figure 5 shows a schematic cross-sectional representation of the in Fig. 4 battery cells shown along the AA direction, and Fig. Figure 6 shows a partially enlarged view of the battery cell at B in Fig. 5. According to some embodiments of the present application, as with reference to the Fig. As shown in Figures 3 to 6, the battery cell 20 refers to the smallest unit of the battery 100, wherein this battery cell 20 includes an electrode assembly 22, a housing 21, and a current-collecting end cap 23. The electrode assembly 22 has a surge arrester 221, which includes a first surge arrester 221A and a second surge arrester 221B. The housing 21 defines a receiving space and an opening located at one end of the receiving space, wherein the receiving space is used to receive the electrode assembly 22. The current-collecting end cap 23 is fixedly connected to the housing 21, the current-collecting end cap 23 seals the opening of the housing 21, and the current-collecting end cap 23 is electrically connected to the first surge arrester 221A.

[0079] The housing 21 has a hollow structure with an internally formed receiving space for receiving the electrode assembly 22. The housing 21 has an opening and an opening end face surrounding the opening, and the housing 21 can be filled internally with an electrolyte. The shape and size of the housing 21 are compatible with the shape and size of the electrode assembly 22. For a cylindrical battery cell 20, both the electrode assembly 22 and the housing 21 can be cylindrical, and for a square battery cell 20, both the electrode assembly 22 and the housing 21 can be square. The material of the housing 21 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, or the like, and embodiments of the present application do not impose any particular restrictions on this.

[0080] The electrode assembly 22 is a component in the battery cell 20 in which an electrochemical reaction takes place. The electrode assembly 22 can include a body section and a trace 221, the trace 221 extending from the body section so that it protrudes from an end section of the body section. The electrode assembly 22 can include a positive electrode plate, a negative electrode plate, and a separator. The electrode assembly 22 can have a wound structure formed by winding a positive electrode plate, a negative electrode plate, and a separator. The electrode assembly 22 can have a laminated structure formed by a laminated arrangement of a positive electrode plate, a negative electrode plate, and a separator.The positive electrode plate includes a positive electrode current collector and a positive electrode active material layer applied to two opposite sides of the positive electrode current collector. The negative electrode plate may include a negative electrode current collector and a negative electrode active material layer applied to two opposite sides of the negative electrode current collector. The body section is the portion of the electrode assembly 22 corresponding to the area of ​​the electrode plate coated with the active material layer, and the trace 221 is the portion of the electrode plate not coated with the active material layer.

[0081] The surge arrester 221 can be divided into a first surge arrester 221A and a second surge arrester 221B, wherein the first surge arrester 221A is connected to the first electrode plate and the second surge arrester 221B is connected to the second electrode plate. The first surge arrester 221A can be connected to the current-collecting end cap 23 to establish the electrical connection between the current-collecting end cap 23 and the housing 21, and the second surge arrester 221B can be electrically connected to the electrode terminals 24, while the electrode terminals 24 and the housing 21 are insulated from each other, so that the housing 21 and the electrode terminals 24 serve as electrode leakage points on the battery cell 20 with opposite polarities for inputting or outputting electrical energy.

[0082] The first arrester 221A and the second arrester 221B can be located at the same end of the electrode assembly 22 or at different ends of the electrode assembly 22. One of the first arresters 221A and the second arrester 221B is a positive arrester and the other a negative arrester. If the first arrester is a positive arrester and the second arrester is a negative arrester, the housing 21 is a positive electrode leakage terminal and the electrode terminal 24 is a negative electrode leakage terminal; and if the first arrester is a negative arrester and the second arrester is a positive arrester, the housing 21 is a negative electrode leakage terminal and the electrode terminal 24 is a positive electrode leakage terminal.

[0083] The current-collecting end cap 23 can be made of a conductive material such as copper or iron. The current-collecting end cap 23 is electrically connected to the first surge arrester 221A and fixedly connected to the housing 21, and the current-collecting end cap 23 serves as an end cap to seal the opening of the housing 21.

[0084] In this embodiment, the current-collecting end cap 23, by being electrically connected to the first current collector 221A and fixedly connected to the housing 21 to seal the opening of the housing 21, can act both as a current-collecting element and as a sealing end cap 23, thus fulfilling the roles of current collection and sealing. This reduces the number of parts and the welding process, thereby simplifying the structure of the battery cell 20 and increasing the space utilization efficiency in the housing, thus reducing the internal resistance of the battery cell 20.

[0085] In some embodiments, the current-collecting end cover 23 is welded to the housing 21, so that the current-collecting end cover 23 is conductively connected to the housing 21.

[0086] The current-collecting end cap 23 is conductively connected to the housing 21 by means of a weld, which can be done by laser welding or ultrasonic welding. The shape and size of the current-collecting end cap 23 are adapted to the housing 21, and a conductive seal is created after the welding of the two.

[0087] Welding can be used to create a conductive, sealed connection between the current-collecting end cover 23 and the housing 21, and to provide the electrodes and seal the battery cell housing, thereby simplifying the battery structure.

[0088] Referring to the Fig. 5 and Fig. 6, in some embodiments the housing 21 includes a main body section 213 and a weld section 214, wherein the main body section 213 surrounds an outer surface of the electrode assembly 22 and the weld section 214 is located at one end of the main body section 213 near the opening, and the current-collecting end cap 23 is welded to the weld section 214 to form a first fusion section 26.

[0089] In this example, the main body section 213 and the weld section 214 are provided sequentially along the axial direction of the electrode assembly 22, and the weld section 214 forms an opening in the housing 21 by surrounding an end remote from the main body section 213. In the case of the cylindrical housing 21, both the main body section 213 and the weld section 214 are annular.

[0090] By welding and fusing the current-collecting end cover 23 with the weld section 214 near an opening end of the housing 21 to form the first fusion section 26, the internal resistance can be reduced while a sealed connection is realized to create a conductive connection, thereby simplifying the structure of the battery end cover.

[0091] According to some embodiments of the present application, the current-collecting end cover 23 includes a first connecting section 232 and a second connecting section 233, which are connected, wherein the first connecting section 232 is electrically connected to the first surge arrester 221A; and the second connecting section 233 is connected to the first connecting section 232, and the second connecting section 233 is welded to the welded section 214 of the housing 21 to form the first fusion connecting section 26.

[0092] The first connecting section 232 on the current-collecting end cover 23 is electrically connected to the first surge arrester 221A, and the second connecting section 233 is electrically connected to the housing 21 to establish the electrical connection of the electrode assembly 22 to the housing 21 via the current-collecting end cover 23. The second connecting section 233 is connected to an end of the first connecting section 232 that is located near an inner surface of the housing 21.

[0093] The shape of the first connecting section 232 is adapted to the shapes of the housing 21 and the electrode assembly 22. The housing 21 is cylindrical, the electrode assembly 22 is circular, and the first connecting section 232 is correspondingly circular. The first connecting section 232 and the second connecting section 233 can be machined into a single piece using a one-piece molding process. This eliminates the assembly process for the first connecting section 232 and the second connecting section 233 and can improve the structural strength of the current-collecting end cap 23 without increasing costs.The second connecting section 233 and the first connecting section 232 can be coplanar, meaning that these two are in the same plane and together form a flat, plate-like, stream-collecting end cap 23, or they can be non-coplanar, meaning that they are irregularly shaped structures that extend separately in different directions. For example, the second connecting section 233 can be formed by bending the plate structure so that the edge of the plate structure is curved.

[0094] In this embodiment, by welding the first current collector 221A and the housing 21 via the first connection section 232 and the second connection section 233, respectively, it is possible to effectively separate the weld seam of the current-collecting end cover 23 with the first current collector 221A from the weld seam of the current-collecting end cover 23 with the housing 21, thus avoiding an adverse effect caused by a laser projected onto the connection point of the current-collecting end cover 23 with the first current collector 221A during the welding of the second connection section 233 with the housing 21. Furthermore, the current-collecting end cover 23 can transfer the current directly from the electrode assembly 22 to the housing 21, which contributes to reducing the internal resistance of the battery cell 20.

[0095] According to some embodiments of the present application, the second connecting section 233 encloses an outer edge of the first connecting section 232 and projects in a direction away from the electrode assembly 22.

[0096] As in Fig. As shown in Figure 6, the second connecting section 233 is provided continuously along the outer edge of the first connecting section 232 and protrudes relative to the surface of the first connecting section 232, and the second connecting section 233 is provided at an angle to the first connecting section 232.The second connecting section 233 can, for example, be perpendicular to the first connecting section 232; or, from one end connected to the first connecting section 232 to the other end remote from the first connecting section 232, the second connecting section 233 can gradually move closer to the central axis of the electrode assembly 22, meaning that an acute angle is formed between the second connecting section 233 and the first connecting section 232; or, from one end connected to the first connecting section 232 to the other end remote from the first connecting section 232, the second connecting section 233 can gradually move further away from the central axis of the electrode assembly 22, meaning that an obtuse angle is formed between the second connecting section 233 and the first connecting section 232.

[0097] The configuration that the first connection section 232 and the second connection section 233 are not coplanar allows the positions where the first fusible connection section 26, formed by welding to the current-collecting end cap 23, is connected to the first current collector 211A, to be arranged separately in different orientations, thus avoiding mutual interference during welding. The second connection section 233, which projects in a direction away from the electrode assembly 22, allows the first fusible connection section 26 to be implemented in any desired manner, such as by internal welding, external welding, or butt welding, to adapt to different welding requirements, which is helpful in ensuring weld quality.

[0098] According to some embodiments of the present application, as in Fig. Figure 6 shows an end face on one side of the second connecting section 233, which is away from the first connecting section 232, flush with an end face on one side of the welded section 214, which is away from the main body section 213, so that the second connecting section 233 and the welded section 214 form the first fusion connecting section 26 by butt welding on the flush end faces.

[0099] The fact that the end surfaces of the second connecting section 233 and the weld section 214 are flush means that the end surfaces of the two are in the same plane, so that the second connecting section 233 and the weld section 214 can be butt-welded to form the first fusion connecting section 26. It is understood that, without affecting butt welding, situations in which the end surfaces of the second connecting section 233 and the weld section 214 are not perfectly coplanar due to manufacturing precision or butt positioning should also fall within the range in which the end surfaces of the second connecting section 233 and the weld section 214 are flush in this embodiment.

[0100] During butt welding, there is sufficient space for the laser to be positioned outside the battery, which contributes to improving the precision of the laser welding and thus the weld quality; at the same time, the first fusion section 26 formed by butt welding is located on the end faces of the second connection section 233 and the weld section 214, which can reduce the length of the second connection section 233, which is fitted together with the weld section 214 in the axial direction of the electrode assembly 22, thereby reducing the amount of the occupied interior space of the battery housing.

[0101] Fig. Figure 7 shows a schematic cross-sectional view of a battery cell, which in some other embodiments of the present application is provided along the AA direction, Fig. Figure 8 shows a schematic structural representation of a current-collecting end cover 23 in some embodiments of the present application, Fig. Figure 9 shows a partially enlarged view at C in Fig. 7, and Fig. Figure 10 shows a partially enlarged view at C in Fig. 7 in some other embodiments. Referring to the Fig. 7-10 According to some embodiments of the present application, the first fusion section 26 is configured such that a laser penetrates the second connection section 233 in a direction that intersects an axis of the electrode assembly 22 and melts the weld section 214 at least partially.

[0102] The fact that the laser, penetrating the second connection section 233 in a direction intersecting the axis of the electrode assembly 22, at least partially melts the weld section 214, means that the second connection section 233 and the weld section 214 form the first fusion connection section 26 by internal welding directed from the inside of the battery to the outside, with the first fusion connection section 26 being located on a side wall of the second connection section 233. For example, the laser can be emitted onto the second connection section 233 in a direction perpendicular to the axial direction X of the electrode assembly 22, and the laser is projected onto the housing 21 after penetrating the second connection section 233, so that the second connection section 233 is welded to the housing 21 to form the first fusion connection section 26.

[0103] When welding using the internal welding process, the emission direction of the laser is directed outside the battery, which can prevent damage to the electrodes from the laser emitted onto the electrode assembly during welding, thus improving the safety of the welding process.

[0104] According to some embodiments of the present application, the first fusion joint section 26 does not penetrate the weld section 214 of the housing 21.

[0105] Since the current-collecting end cap must collect the current generated by the electrodes, a material with high conductivity, such as copper, is typically used, while for the housing, more attention is paid to the need for structural strength, so carbon steel or stainless steel is usually used. Because different materials have different absorption rates and coefficients of thermal expansion for lasers, the weld seam (i.e., the first fusion section 26) of the second connection section 233 to the weld section 214 generates large stresses, which makes the first fusion section 26 susceptible to cracking.The parameters of the laser welding can be controlled during the welding process in such a way that the first fusion section 26 does not penetrate the weld section 214, which helps to reduce the tearing of the first fusion section 26 formed by welding due to penetration of the weld section 214 and thus the influence on the structural strength and sealing performance of the battery.

[0106] According to some embodiments of the present application, as in Fig. 9 shown, the second connecting section 233 has a thickness of t1 in a direction perpendicular to an axis of the electrode assembly 22, and the second connecting section has a height of h0 in an axial direction of the electrode assembly 22, t1 and h0 satisfy: 2 ≤ h0 / t1 ≤ 6.

[0107] As is understandable, there are a variety of scenarios for h0 / t1 when h0 / t1 < 2. One scenario is that 1 ≤ h0 / t1 < 2, where in this case the value of h0 is chosen to be small so that when the laser is projected along the axial direction X of the electrode assembly 22 between the second connection section 233 and the inner surface of the housing 21 to form the first fusion connection section 26 by welding, the laser can easily be projected onto the surface of the first connection section 232 opposite the electrode assembly 22, resulting in partial melting at the connection between the second connection section 233 and the first connection section 232. Due to the existence of a narrow slot between the outer surface of the connection in a chamfered structure and the inner surface of the housing 21, the laser can be projected through the narrow slot onto the electrode assembly 22, resulting inthat the electrode assembly 22 is hit and damaged; and another scenario is that h0 / t1 < 1, which means that h0 < t1, where in this case the value of h0 takes on a smaller value and there is a greater risk that the electrode assembly 22 is hit and damaged by the laser.

[0108] If h0 / t1 > 6, this means that h0 > 6t1, in which case the value of h0 is too large, so that the second connecting section 233 excessively occupies the space inside the housing 21 along the axial direction X of the electrode assembly 22, and then the number of electrode plates that can be accommodated inside the battery cell 20 will be small, which will lead to the low energy density of the battery cell 20.

[0109] The inventors of the present application have determined, after extensive experimental analyses, that the value of h0 is moderate when the ratio of h0 to t1, h0 / t1, is greater than or equal to 2 and less than or equal to 6. In this case, when the laser is projected along the axial direction X of the electrode assembly 22 between the second connection section 233 and the inner surface of the housing 21 to form the first fusion connection section 26 by welding, it is less likely that the connection between the second connection section 233 and the first connection section 232 will be struck and melted by the laser. This, in turn, reduces the risk of damage to the electrode assembly 22 caused by the laser passing through the narrow slot and the inner surface of the housing 21 at the connection of the beveled structure.At the same time, the space occupied by the second connecting section 233 within the housing 21 along the axial direction X of the electrode assembly 22 is reduced as much as possible, which makes it possible to accommodate a larger number of electrode plates within the battery cell 20 without changing the overall height of the battery cell 20, which in turn contributes to increasing the capacity for active materials in the battery cell 20 and can thus improve the energy density of the battery cell 20.

[0110] In some embodiments, h0 / t1 can also be configured as 3 ≤ h0 / t1 ≤ 5. After extensive experimental analyses, the inventors of the present application have determined that the value of h0 is more appropriate when the relationship between h0 and t1 satisfies 3 ≤ h0 / t1 ≤ 5, which better meets the laser welding requirement for the size of the second connection section 233 along the axial direction X of the electrode assembly 22 and the energy density of the battery cell 20.

[0111] According to some embodiments of the present application, t1 of the second connection section 233 satisfies 0.1 mm ≤ t1 ≤ 0.5 mm.

[0112] In some embodiments, t1 can further be designed as 0.2 mm ≤ t1 ≤ 0.4 mm. Regarding the thickness t2 of the first connection section 232, reference can be made to the thickness t1 of the second connection section 233. That is, the range of values ​​for t2 can be: 0.1 mm ≤ t1 ≤ 0.5 mm. In some embodiments, t2 can also further be designed as 0.2 mm ≤ t1 ≤ 0.4 mm, so that the current-collecting end cap 23 can better meet the welding requirements, overcurrent capability, and strength requirements. In one example, the thickness t2 of the first connection section 232 and the thickness t1 of the second connection section 233 can be the same, which makes it possible to machine and form the current-collecting end cap 23 from a single component, thereby reducing manufacturing costs.

[0113] By selecting a suitable thickness for the second connection section, the strength and overcurrent capability of the current-collecting end cover 23 can be balanced, thereby optimizing the internal connection structure of the battery.

[0114] According to some embodiments of the present application, an outer surface of the second connecting section 233 is in an interference fit with an inner surface of the welded section 214.

[0115] This embodiment can be applied in particular to a solution in which the housing 21 is cylindrical, the first connecting section 232 is correspondingly circular and the second connecting section 233 has an annular structure.

[0116] By ensuring that the second connecting section 233 and the housing 21 are in a press fit, there is no gap between the outer surface of the second connecting section 233 and the inner surface of the housing 21 after the current-collecting end cap 23 has been installed inside the housing 21, so that the current-collecting end cap 23 and the housing 21 can be firmly connected, which makes the connection reliable and at the same time reduces faulty welding and leakage welding due to an excessively large gap and damage to the electrode assembly by the escaping laser during welding, thus contributing to ensuring weld quality.

[0117] As in Fig. As shown in Figure 8, according to some embodiments of the present application, the second connection section 233 comprises a plurality of first projecting sections 2331, which are provided at intervals and project in a direction away from the electrode assembly 22, and second projecting sections 2332, which are located between two adjacent first projecting sections 2331, wherein the height of the second projecting sections 2332 is less than that of the first projecting sections 2331 in the axial direction of the electrode assembly 22; and the first projecting sections 2331 and the second projecting sections 2332 are separately welded to the weld section to form parts of the first fusion connection section 26.

[0118] The number of second projecting sections 2332 is not limiting; for example, one or more second projecting sections 2332 may be provided. If a plurality of second projecting sections 2332 are provided, the second connecting section 233 is subdivided into a plurality of arc-shaped connecting segments of different heights, which are provided alternately, and the height of the second projecting sections 2332 is less than the height of the first projecting sections 2331, so that a gap may be formed between two adjacent first projecting sections 2331.

[0119] The second connecting section 233 and the first connecting section 232 can be joined by means of chamfers or chamfer rounding transitions, and to avoid laser leakage during welding, the height of the second projecting section 2332 can be adjusted to be greater than the height of the chamfered rounded projecting surface of the first connecting section.

[0120] This design can allow the first foregoing section 2331 to exhibit some deformability during assembly, especially when the second connecting section 233 is in a press fit with the welded section 214 of the housing 21, which better balances the structural strength of the current-collecting end cover and the feasibility of assembly and positioning.

[0121] According to some embodiments of the present application, a plurality of second preceding sections 2332 are evenly distributed centered around a central axis of the electrode assembly 22.

[0122] It is understood that the multitude of second projecting sections 2332 are distributed at uniform intervals, and the first projecting sections 2331, which are provided alternately with the second projecting sections 2332, are also distributed at uniform intervals, so that portions of the first fusion joint section 26, which are formed by welding the first projecting sections 2331 and the second projecting sections 2332 separately with the weld section 214, are uniformly distributed along the circumferential direction. Such a structural design allows the first fusion joint section 26, which is formed between the current-collecting end cap 23 and the housing 21, to maintain a symmetrical structure, which can improve the impact resistance of the weld mark, thereby preventing the weld mark from tearing due to uneven force upon impact from an external force.

[0123] According to some embodiments of the present application, as in the Fig. 9 and Fig. Figure 10 shows an inner diameter D2 of the main body section 213 smaller than an inner diameter D1 of the welded section 214, such that a step surface is formed at a connection of an inner surface of the main body section 213 with an inner surface of the welded section 214, with the current-collecting end cap 23 resting on the step surface.

[0124] For the inner diameters of the main body section 213 and the weld section 214, there can be a direct abrupt change from D2 to D1 at the joint position, in which case a right-angled or nearly right-angled step surface is formed, or there can be a gradual transition change, such as a chamfered or rounded transition joint.

[0125] The difference in the inner diameters of the main body section 213 and the welded section 214 causes a stepped surface to be formed at a joint between the two, and the current-collecting end cover 23 can be positioned by means of this stepped surface, thus achieving more convenient butt positioning, which improves assembly efficiency.

[0126] According to some embodiments of the present application, as in Fig. Figure 9 shows a wall thickness of the main body section 213 equal to a wall thickness of the welded section 214.

[0127] If the wall thickness of the main body section 213 is equal to the wall thickness of the welded section 214, the fact that the inner diameter D1 of the welded section 214 is larger than the inner diameter D2 of the main body section 213 means that the welded section 214 extends outwards overall in relation to the main body section 213, that is, the outer diameter of the welded section 214 is also larger than the outer diameter of the main body section 213, which makes it possible to maintain the strength of the housing 21 while forming a stepped section for better positioning of the current-collecting end cover 23.

[0128] According to some embodiments of the present application, as in Fig. Figure 10 shows an outer surface of the main body section 213 coplanar with an outer surface of the welded section 214.

[0129] The outer surface of the main body section 213, which is coplanar with the outer surface of the weld section 214, means that the outer surfaces of the main body section 213 and the weld section 214 are flat surfaces and the outer diameters of the two are the same, and that if the inner diameter D2 of the main body section 213 is smaller than the inner diameter D1 of the weld section 214, this means that the thickness of the weld section 214 is smaller than the thickness of the main body section 213 and that it is the inner side section of the weld section 214 that is cut off, forming a step surface between the inner side surfaces of the weld section 214 and the main body section 213.

[0130] The coplanarity of the outer surface of the main body section 213 with the outer surface of the welded section 214 can maintain the consistency of the dimensions of the outer surfaces of the battery cells, which facilitates the combined assembly of a large number of battery cells.

[0131] According to some embodiments of the present application, the inner diameter D1 of the weld section 214 and the inner diameter D2 of the body section 213 satisfy: D1 - D2 ≥ 0.1 mm.

[0132] The inventors of the present application have determined, after extensive experimental analyses, that the values ​​of D1 and D2 can also be chosen such that they satisfy D1 - D2 ≥ 0.2 mm, so that the step surface formed between the welded section and the main body section has a certain width for placing the current-collecting end cover 23, thereby providing the positioning for mounting the current-collecting end cover 23 in order to increase the precision of mounting the current-collecting end cover 23 and to increase the efficiency of the assembly.

[0133] Fig. Figure 11 shows a schematic structural representation of a schematic cross-sectional representation of a battery cell, which is provided in some further embodiments of the present application along the AA direction. Fig. Figure 12 shows a partially enlarged view at D in Fig. 11, and Fig. Figure 13 shows a schematic structural representation of a sealing element. According to some embodiments of the present application, the housing 21 includes, as shown in the Fig. Figures 11-13 show a bent section 212, wherein the bent section 212 is connected to an end of the welded section 214 that is away from the main body section 213 and is bent towards an inside of the welded section 214 to form a gap between the bent section 212 and the welded section 214, wherein at least a part of the second connecting section 233 is located inside the gap.

[0134] The curved section 212 can, for example, be a flange structure formed by partially bending one end of the opening enclosed by the housing 21 towards the interior of the housing 21. In this example, during the assembly of the battery cell 20, after the current-collecting end cap 23 has been fitted into the housing 21, the curved section 212 can be formed at the opening position of the housing 21 by bending the housing 21, thus simplifying the shaping process.

[0135] By providing the curved section 212, the displacement of the current-collecting end cap 23 can be limited to prevent it from detaching from the housing 21, thus ensuring a reliable connection between the current-collecting end cap 23 and the housing 21. Furthermore, if the curved section 212 is formed by bending the housing 21, implementation becomes simpler and costs can be effectively reduced.

[0136] Referring to Fig. 12 The battery cell 20 according to some embodiments of the present application further includes a sealing ring 27, wherein the sealing ring 27 is located within the gap formed between the bent section 212 and the welded section 214, and the sealing ring 27 is at least partially clamped between the second connecting section 233 and the bent section 212.

[0137] The sealing ring 27 can be made of a metallic material or of an elastic material such as rubber, plastic, or the like. If the material forming the sealing ring 27 is plastic, it can specifically be polybutylene terephthalate (PBT) or soluble polytetrafluoroethylene (PFA). The second connecting section 233 and the bent section 212 clamp the sealing ring 27, and the second connecting section 233 is in a sealed fit with the bent section 212.

[0138] In this way, for the battery cell 20, in which the current-collecting end cover 23 is able to insulate the cavity in the housing 21 from the external environment, the sealing performance of the battery cell 20 can be further improved by providing the sealing ring 27, which helps to avoid electrolyte leakage.

[0139] Referring to Fig. 12 According to some embodiments of the present application, the curved section 212 includes a connecting edge 2121 and an annular edge 2122, wherein the annular edge 2122 is connected to the welded section 214 of the housing 21 via the connecting edge 2121, with one end of the annular edge 2122, which is away from the connecting edge 2121, being located near the electrode assembly 22; and the sealing ring 27 includes a first sealing body 271 and a second sealing body 272, which are connected, wherein the first sealing body 271 is clamped between the second connecting section 233 and the annular edge 2122 and the second sealing body 272 is clamped between one side of the second connecting section 233 opposite the electrode assembly 22 and the connecting edge 2121.

[0140] Among these, the connecting edge 2121 can be a straight edge or an arcuate edge, which is not limited in this embodiment. The second sealing body 272 fits the connecting edge 2121.

[0141] Thus, the structural design of the sealing ring enables the second connecting section 233 to achieve a sealed fit with both the annular edge 2122 and the connecting edge 2121, resulting in a better sealing effect.

[0142] According to some embodiments of the present application, the first sealing body 271 includes a first surface facing the second connecting section 233 and a second surface facing the annular edge, wherein the first surface abuts the second connecting section 233, the second surface abuts the annular edge 2122, and at least one of the first surface and the second surface is provided with a third projecting section 273.

[0143] Schematically, the first surface is provided with a third projecting section 273, or alternatively, the second surface is provided with a third projecting section 273. In some embodiments, both the first and second surfaces can be provided with a third projecting section 273. The third projecting section 273 further improves the sealing performance of the surface fit, helping to prevent electrolyte leakage from the gap between the current-collecting end cap 23 and the housing 21.

[0144] Referring to Fig. 13 The third preceding section 273, according to some embodiments of the present application, has a width of a in an axial direction of the electrode assembly 22 and a height of b along a direction perpendicular to the axial direction of the electrode assembly 22, wherein a and b satisfy: 0.5 mm ≤ a ≤ 2 mm and 0.2 mm ≤ b ≤ 0.5 mm.

[0145] In this embodiment, by preferably selecting the size of the third preceding section 273, the clamping effect of the first sealing body 271 on the second connecting section 233 and the annular edge 2122 can be improved, and thus the sealing effect of the first sealing body 271 can be improved.

[0146] Fig. Figure 14 shows a structural schematic diagram of a current-collecting end cap connected to a first surge arrester in some embodiments of the present application, and Fig. Figure 15 shows a schematic structural representation of a current-collecting end cap connected to a first surge arrester in some other embodiments of the present application. Referring to the Fig. 14-15 the first connecting section 232 according to some embodiments of the present application is welded to the first drain 221A to form the second fusion connecting section 25.

[0147] The conductive connection of the first connection section 232 with the first current collector 221A is realized by welding in order to collect the current from the electrode plates to the current-collecting end cap 23 and conduct it to the housing 21. The welding can be laser welding or ultrasonic welding, and in some examples the second fusion connection section 25 can be formed by emitting a laser along the axial direction of the electrode assembly, which penetrates the first connection section 232 and then melts and finally hardens the first current collector 221A.

[0148] The formation of the second fusion section 25 by welding makes it possible to permanently connect the current-collecting end cover 23 to the electrode assembly 22, which improves the overall strength of the battery, so that a stable conductive connection between the current-collecting end cover 23 and the electrode assembly 22 can be realized even in the event of an impact of an external force.

[0149] According to some embodiments of the present application, the first connecting section 232 includes a first side surface facing the electrode assembly 22 and a second side surface facing away from the electrode assembly 22, wherein at least one of the first side surface and the second side surface is provided with at least one reinforcing rib 231 projecting from a surface on which it is located, the reinforcing rib 231 being used to reinforce the current-collecting end cap 23.

[0150] The material of the current-collecting end cap 23 is typically a highly conductive material, such as copper, but its inherent strength is not very high, making it prone to deformation under external force. This deformation, in turn, affects the conductive connections between the current-collecting end cap 23 and the first surge arrester 221A and the housing 21. The first connection section of the current-collecting end cap 23, which is provided with a reinforcing rib 231 projecting from the plane in which it is located, can improve the deformation resistance of the current-collecting end cap 23. The reinforcing rib 231 can be provided on the first side face, the second side face, or both sides simultaneously, and there is no limit to the number of reinforcing ribs 231, which can be one or more.

[0151] Fig. Figure 16 shows a schematic cross-sectional view of a current-collecting end cap of some embodiments of the present application. According to some embodiments of the present application, as shown in Fig. Figure 16 shows that at least a part of the reinforcing rib 231, which is located on the first side surface of the first connection section 232 facing the electrode assembly 22, is welded to the first arrester 221A to form the second fusion connection section 25.

[0152] Since the reinforcing rib 231 protrudes from the surface on which it is located, it can, when located on the first side face, abut the first arrester 221A when the current-collecting end cap 23 is aligned with the electrode assembly 22, and welding the reinforcing rib 231 to the first arrester 221A can reduce faulty welding due to the gap between the two, in order to ensure the quality of the welding of the second fusion section 25, and at the same time the second fusion section 25 formed by welding can further improve the strength of the current-collecting end cap 23.

[0153] According to some embodiments of the present application, the reinforcing rib 231 for forming the second fusion section 25 is a stamped groove, wherein one side of the stamped groove is recessed into a second side surface of the first connection section 232 opposite the electrode assembly 22.

[0154] The stamped groove is a component formed by stamping the plane of the first connection section and projects as a whole to the surface on one side of the first connection section. Producing a stamped groove as a reinforcing rib on the first connection section 232 by stamping is a simple and cost-effective process and does not increase the weight of the current-collecting end cap. The recess on the side opposite the electrode assembly 22 can also be used to indicate a welding position for forming the second fusion connection section 25, thus simplifying the welding positioning.

[0155] According to some embodiments of the present application, the second fusion connection section 25 is arranged at uniform intervals along a circumferential direction of a center of the first connection section 232.

[0156] The number of second fusion joint sections 25 formed by welding can be a plurality, and the exact number can be arranged according to actual requirements. The plurality of second fusion joint sections 25 can be provided at equal intervals around the center of the first fusion section 232. For example, as in Fig. As shown in Figure 14, four second fusible link sections 25 are formed between the current-collecting end cover 23 and the first arrester 221A, and these four second fusible link sections 25 are evenly distributed around the central axis of the electrode assembly 22.

[0157] In this embodiment, the electrical energy of the electrode assembly 22 can be transferred uniformly to all parts of the current-collecting end cover 23, thereby further improving the uniformity of the transfer of electrical energy, which suppresses an uncontrolled temperature rise due to excessive current flow through partial positions of the current-collecting end cover 23.

[0158] According to some embodiments of the present application, the second fusion section 25 is composed of a plurality of radially extending spoke-like patterns or a plurality of crescent-shaped patterns.

[0159] Referring to Fig. 15 The plurality of strip-shaped second fusible link sections 25 in this embodiment can be considered as radiating outwards from the central position of the current-collecting end cap 23. In this way, the second fusible link section 25 enables the current to be directed to a position of the current-collecting end cap 23 near the central area and to an edge of the current-collecting end cap 23 near the inner surface of the housing 21, which allows the current-collecting end cap 23 to conduct electrical energy uniformly.

[0160] According to some embodiments of the present application, the second fusion section 25 has, it is said to Fig. Referenced in 15, an overall crescent-shaped pattern, can specifically include a first segment, an arc segment, and a second segment connected sequentially, with the first and second segments located on the side where the circular center of the arc segment is situated, and the distance between the first and second segments gradually increasing from the side near the arc segment to the side away from the arc segment. Among these, the circular center of the arc segment is located on the side of the arc segment furthest from the central axis of the electrode assembly 22.

[0161] In this way, the second fusible link section 25 enables the current to be directed to a central position of the current-collecting end cap 23 and to an edge of the current-collecting end cap 23 near the inner surface of the housing 21, thus allowing the current-collecting end cap 23 to conduct electrical energy uniformly. Furthermore, the design of the arc segment connecting the first and second segments allows the arc segment to have a rounded transition, which can mitigate the occurrence of stress concentrations compared to a sharp transition between the first and second segments.

[0162] Referring to Fig. 16 According to some embodiments of the present application, the first connection section 232 includes a surge arrester connection section 2321 and a pressure relief section 2322, wherein the surge arrester connection section 2321 is welded to the first surge arrester 221A to form a second fusible connection section 25, and the pressure relief section 2322 is configured to relieve an internal pressure of the battery cell when the internal pressure or temperature of the battery cell reaches a threshold.

[0163] The pressure relief section 2322 can include a pressure relief function module with a pressure relief function, such as a pressure relief valve, and the pressure relief valve can be integrally and permanently connected to the first connection section 232 of the current-collecting end cover 23, for example, by reserving a mounting hole on the first connection section 232 and subsequently permanently mounting the pressure relief valve in the reserved mounting hole by welding. Since the discharge connection section 2321 must be welded to the discharge of the electrode assembly 22, the pressure relief section 2322 must be offset from the discharge connection section 2321 in order to suppress adverse effects on the realization of the pressure relief function of the pressure relief section 2322 due to the second fusion connection section 25 formed by the weld.

[0164] In this way, if a phenomenon such as a short circuit or overcharging occurs within battery cell 20, the battery cell 20 is susceptible to a sudden increase in internal pressure due to internal thermal runaway. The pressure relief mechanism is designed so that when the internal pressure of battery cell 20 reaches the threshold, it can perform its pressure relief function to reduce fire, explosion, and other safety risks that can easily occur during the use of battery cell 20.

[0165] According to some embodiments of the present application, the drain connection section 2321 surrounds, as in Fig. Figure 16 shows an outside of the pressure relief section 2322.

[0166] After the current collector connection section 2321 is connected to the current collector, the current is collected through the current collector to the first connection section 232 and then directed to the casing, and since the pressure relief section 2322 must rupture when the temperature or pressure inside the battery cell 20 reaches a predetermined threshold in order to achieve pressure relief, its structural design is necessarily different from that of the flat current-collecting end cap, which may adversely affect the internal resistance of the end cap through which the current flows.The discharge connection section 2321 is arranged on the outside of the pressure relief section 2322, so that the current of the electrode plate flows through the second connection section 233, the first fusible link section 26 and the housing 21 after passing through the second fusible link section 25, without having to pass through the pressure relief section 2322, which has a non-uniform thickness, thereby reducing the effect of the pressure relief section 2322 on the internal resistance.

[0167] According to some embodiments of the present application, the drain connection section 2321 and the pressure relief section 2322 are provided in a one-piece formed manner.

[0168] The surge arrester connection section 2321 is provided directly with the pressure relief section 2322 in a one-piece molded configuration, and the pressure relief function module can be provided directly on the surface of the pressure relief section 2322. This reduces the welding required between the pressure relief section 2322 and the surge arrester connection section 2321, thus avoiding mutual interference between the welding processes of the two and saving labor hours, thereby improving production efficiency.

[0169] Fig. Figure 17 shows a schematic structural representation of a current-collecting end cover, which is provided in some further embodiments of the present application, and Fig. Figure 18 shows a schematic cross-sectional view of a current-collecting end cap, which is provided in some further embodiments of the present application. According to some embodiments of the present application, the pressure relief section 2322 includes, as shown in the Fig. Figures 17-18 show a grooved groove 2323, wherein the grooved groove 2323 is configured to tear along the grooved groove 2323 to release the internal pressure of the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches the threshold.

[0170] The grooved groove 2323 is a groove recessed into the surface, formed by machining the surface of the first connection section 232, such that the thickness at the location of the grooved groove 2323 is reduced compared to the thickness of the other locations, thus weakening the strength. This is so that if the battery cell 20 experiences an overcharge or an internal short circuit, leading to irreversible changes in the positive electrode active material and decomposition of the electrolyte, the battery cell 20 generates a large amount of gases. This results in a sharp increase in the atmospheric pressure inside the battery cell 20. When the atmospheric pressure inside the battery cell 20 reaches a threshold, the atmospheric pressure first acts on the part of the first connection section 232 that has the grooved groove 2323, causing the first connection section 232 to crack along the grooved groove 2323.and the gases inside battery cell 20 are released outside battery cell 20 to relieve the air pressure inside battery cell 20, in order to help maintain the safety of battery cell 20.

[0171] Pressure relief is facilitated by providing grooved slots on the surface, eliminating unnecessary welding and not at the expense of the battery's weight and space.

[0172] According to some embodiments of the present application, the grooved groove 2323 is located on the surface of the first connecting section 232, which faces the first side surface of the electrode assembly 22.

[0173] If the material of the current-collecting end cap 23 is copper, its outer surface will be oxidized or corroded by contact with the outside world, and the position of the groove where the notched part is located, if oxidized or corroded, will affect the set threshold for the occurrence of a fracture, resulting in a failure of the pressure relief function.

[0174] In this embodiment, the grooved groove 2323 is arranged on the first side surface of the first connecting section 232, which faces the electrode assembly 22, so that the grooved groove is located inside the battery cell 22 to suppress a failure of the pressure relief function due to oxidation or corrosion.

[0175] According to some embodiments of the present application, the grooved groove 2323 is an annular groove centered in the middle of the first connecting section 232.

[0176] It can be understood that the grooved groove 2323 can be a closed annular groove or an open annular groove, such as a circular arc.

[0177] The grooved groove 2323 with a regular pattern can mitigate an inconsistent pressure drop across the grooved groove, which is more conducive to setting and controlling the pressure or temperature threshold for pressure relief.

[0178] Referring to Fig. According to some embodiments of the present application, the central angle ∝ corresponding to the grooved groove in 17 has a range of values ​​of: 270° ≤∝≤ 330°.

[0179] By selecting a suitable center point angle, it can be better adapted to the material and thickness of the current-collecting end cap as well as the set pressure relief threshold, thereby better meeting the pressure relief requirements.

[0180] Referring to Fig. 11, according to some embodiments of the present application, the first connecting section 232 further comprises a central area 2324, wherein the central area 2324 is a projection area of ​​a central hole of the electrode assembly 22 on the first connecting section 232; and the grooved groove 2323 is located on the circumference of the central area 2324.

[0181] The central area 2324 corresponds to the central hole of the electrode assembly 22, and the closer the position of the grooved slot 2323 is to the center, the more difficult it is to control its pressure relief threshold. Therefore, during position adjustment, the central area 2324, the grooved slot 2323, and the drain connection section 2321 are adjusted sequentially outwards from the center of the first connection section 232, so that the grooved slot 2323 is located on the circumference of the central area 2324 and on the inside of the drain connection section 2321. This avoids the drain connection section and the central hole, thus better ensuring the realization of the pressure relief function.

[0182] According to some embodiments of the present application, the central region 2324 is a circular region and the grooved groove is an annular groove centered in the middle of the first connecting section, wherein a diameter of the central region 2324 is d1; and a minimum diameter of the grooved groove 2323 is d2, wherein d2d1≤4.

[0183] The grooved groove 2323 is a groove with a specific width, and limiting the minimum diameter of the grooved groove 2323 to being larger than the diameter of the central area 2324 ensures that the grooved groove 2323 is located outside the central area. This allows for easier convergence through the central hole and pressure to be applied to the grooved groove 2323 on the end cap 23, causing the grooved groove 2323 to rupture and release the pressure when the preset condition is met.

[0184] According to some embodiments of the present application, the surge arrester connection section 2321 is provided with at least one stamped groove which is welded to the first surge arrester 221A to form the second fusible connection section 25, wherein the grooved groove 2323 is located between the surge arrester connection section 2321 and the central area 2324.

[0185] The groove of the grooved slot 2323 makes the thickness of the position where it is located thin and is therefore not suitable to be arranged on the path through which the current flows on the current-collecting end cap; at the same time, the surface of the arrester connection section 2321 is provided with a stamped groove which is connected to the arrester, and thus, if the grooved slot 2323 is located on the circumference of the arrester connection section 2321, both the stamped groove and the weld have an influence on the grooved slot, which leads to damping or inconsistency of the burst pressure.

[0186] Therefore, the arrangement of the grooved slot 2323 between the drain connection section 2321 and the central area 2324 can suppress an adverse influence on the current collection effect of the current-collecting end cover and also facilitate the realization of the pressure relief function of the grooved slot.

[0187] According to some embodiments of the present application, the first connecting section 232 is circular, the maximum diameter of the second fused connecting section 25 is d3, and the diameter of the first connecting section is d4, and d3 < d4.

[0188] The maximum diameter d3 of the second fusion joint section 25 refers to the diameter of a circle centered at the midpoint of the first fusion joint section 232 and having a radius equal to the distance of the endpoint of the second fusion joint section 25 that is furthest from the center of the first fusion joint section 232 relative to the center of the first fusion joint section 232. The maximum diameter of the second fusion joint section 25, which is smaller than the diameter of the first fusion joint section 232, allows the position of the second fusion joint section 25 to be spaced away from the housing 21 and the first fusion joint section 26, thus preventing any impairment of weld quality due to mutual influence during welding.

[0189] According to some embodiments of the present application, the central area 2324 is a circular area centered in the middle of the first connecting section 232, and the grooved groove 2323 is an annular groove centered in the middle of the first connecting section 232, and the central area 2324 has a diameter of d1; the grooved groove has a minimum diameter of d2, the second fusible link section has a maximum diameter of d3, and the first connecting section 232 has a diameter of d4. The applicant has determined through research that the internal resistance of the battery is low when the dimensions of the current-collecting end cap 23 satisfy: 0.8≤d42−d32d22−d12≤1.2.

[0190] According to some embodiments of the present application, as in Fig. Figure 18 shows that the current collector connection section 2321 of the first connection section 232 has a minimum thickness of t3 along an axial direction of the electrode assembly 22, a material of the current collector end cap 23 has a modulus of elasticity of E, and the electrode assembly 22 has a weight of W, wherein t3×EW≥7000mm−1.

[0191] Since the current-collecting end cap 23 is located at the open end of the battery housing, it must support the weight of the electrode assembly 22 inside the housing 21, which places certain demands on the strength of the current-collecting end cap 23. By adjusting the parameters of the current-collecting end cap 23 described above, its load-bearing capacity can be ensured to mitigate deformation or even breakage under the weight of the electrode assembly 22.

[0192] It is worth noting that if the current-collecting end cap 23 is made of a single material, the modulus of elasticity E of the material forming the current-collecting end cap 23 can be found according to existing standards and specifications, whereas if the current-collecting end cap 23 is made of a variety of materials, the modulus of elasticity of the material forming the current-collecting end cap 23 can be determined on the basis of tests.

[0193] To illustrate, the test step for the elastic modulus E can include the following: i. Cutting the current-collecting end cap into metal strips to obtain a test sample with a cross-sectional area of ​​S0; ii. Applying a pressure F to the test specimen using a testing machine to deform the test specimen, and recording the amount of deformation ΔL el ; and iii. Calculate the modulus of elasticity E according to the applied pressure F and the amount of deformation ΔL.

[0194] Among these, the specific implementation of the calculation of the modulus of elasticity E according to the applied pressure and the amount of deformation can be as follows: The pressure and the corresponding amount of deformation are formed into a deformation-force curve, and two points are taken on the curve, and the modulus of elasticity E is calculated according to the difference in pressure and the difference in the amount of deformation between the two points and the cross-sectional area S0.

[0195] A stamped groove can be formed on the current collector connection section 2321 by stamping the first connection section 232 for use in a welded connection with the electrode assembly, and the thickness of the current collector connection section 2321 is thinned due to the elongation during the stamping process, and the minimum thickness of the current collector connection section 2321 is the minimum thickness of the current collector end cap 23 except for the grooved groove, and it can be used in a strength calibration to more accurately reproduce the strength of the current collector end cap.

[0196] According to some embodiments of the present application, as in Fig. Figure 10 shows that at least one of two opposing surfaces of the housing 21 and the current-collecting end cover 23 is provided with a paste mask layer.

[0197] Different materials have different melting points, laser absorption rates, and coefficients of thermal expansion. When the current-collecting end cap 23 is laser-welded to the housing 21, an effective weld mark may not form, or cracks may occur, due to the significant material difference. Applying a paste mask layer to the weld surface can aid the welding process and improve weld quality. The two opposing surfaces of the housing 21 and the current-collecting end cap 23 are two surfaces that are in close proximity when joined. The paste mask layer can be formed on the surfaces of the housing 21 and / or the current-collecting end cap 23 by deposition or electroplating.

[0198] In some examples, the material of the first layer is copper and the material of the second layer is carbon steel. The material of the paste mask layer is nickel.

[0199] The paste mask layers can be formed by electroplating nickel-plated layers onto the surfaces of the current-collecting end cap 23 and the housing 21. It is understood that the paste mask layers can be plated onto the entire surfaces of the current-collecting end cap 23 and the housing 21, or, depending on the specific position of the weld joint, the surfaces of the area where the weld is located can be plated with the paste mask layers to facilitate welding.

[0200] According to some embodiments of the present application, as in Fig. Figure 10 shows that a surface of the current-collecting end cap 23, facing the housing 21, is provided with a first paste mask layer 235, and a surface of the housing 21, facing the current-collecting end cap 23, is provided with a second paste mask layer 215, wherein the first paste mask layer 235 has a thickness of u1 and the second paste mask layer 215 has a thickness of u2, where 1 µm ≤ u1 + u2 ≤ 9 µm. In some examples, u1 and u2 can also satisfy 2 µm ≤ u1 + u2 ≤ 8 µm.

[0201] In this embodiment, by reasonably adjusting the thickness of the paste mask layers, it is possible to control the weight of the end cap and the housing while simultaneously supporting welding, thereby reducing unnecessary weight loss.

[0202] Referring to Fig. 5 According to some embodiments of the present application, the electrode assembly 22 further includes a second arrester 221B with a polarity that differs from that of the first arrester 221A; and the battery cell further includes electrode terminals 24, wherein the electrode terminals 24 are located at an end of the housing 21 that is away from the opening and are electrically connected to the second arrester 221B.

[0203] The first arrester 221A and the second arrester 221B are located separately on different sides of the electrode assembly 22, wherein the first arrester 221A is conductively connected to the housing 21 via the current-collecting end cover 23 and the second arrester 221B is electrically connected to the electrode terminal 24, wherein the electrode terminal protrudes from the housing 21 and is provided insulated from the housing 21.

[0204] The structure of the battery cell 20 of the present application is illustrated below by a specific embodiment using a cylindrical battery cell 20 as an example.

[0205] The Fig.Figures 3 to 18 show a battery cell 20, the battery cell 20 comprising a housing 21, an electrode assembly 22, a current-collecting end cap 23, and electrode terminals 24. The housing 21 has an opening and an opening end face surrounding the opening, and the housing 21 has an end wall 211 directly opposite the opening, the electrode terminals 24 being mounted on the end wall 211. The electrode assembly 22 is provided within the housing 21, the electrode assembly 22 has a cylindrical shape, and the electrode assembly 22 comprises a first arrester 221A and a second arrester 221B, the first arrester 221A and the second arrester 221B being located on opposite sides of the electrode assembly 22, and the second arrester being electrically connected to the electrode terminals 24.

[0206] The current-collecting end cap 23 is provided in the housing 21 and closes the opening of the housing 21. The current-collecting end cap 23 includes a first connection section 232 and a second connection section 233, wherein the first connection section 232 has a flat plate structure, and the second connection section 233 is connected to the first connection section 232 and has an annular structure. The first connection section 232 is welded to the first surge arrester 221A, forming a second fusible link section 25, and the second connection section 233 is welded to an inner surface of the housing 21, forming a first fusible link section 26. Three, four, or six, and the like, second fusible link sections 25 are formed among these, the plurality of second fusible link sections 25 being uniformly distributed around a central axis of the electrode assembly 22.

[0207] The first connecting section 232 is provided successively from the center outwards with a central area 2324, a pressure relief section 2322 and a drain connecting section 2321, wherein the central area 2324 is a projection area of ​​a central hole of the electrode assembly 22 on the first connecting section, the pressure relief section 2322 includes a circular grooved groove 2323 and the drain connecting section 2321 includes a plurality of reinforcing ribs 231. In some embodiments, the reinforcing rib 231 is a stamped groove projecting towards the electrode assembly 22, and the stamped groove is welded to the first current collector 221A of the electrode assembly to form the second fusible link section 25, and the grooved groove 2323 is located between the central area 2324 and the current collector link section 2321, avoiding the second fusible link section 25.

[0208] The connection between the first connecting section 232 and the second connecting section 233 can be formed with a rounded transition, so that this connection is designed as a chamfered corner. The outer diameter of the annular second connecting section 233 is larger than the inner diameter of the housing 21, so that the second connecting section 233 is in an interference fit with the cavity of the housing 21 and the second connecting section 233 is provided with a second projecting section 2332, wherein a height dimension X of the second projecting section 2332 along the axial direction of the electrode assembly 22 is less than h0.

[0209] The second connecting section 233 is welded to the inner surface of the housing 21 and forms the first fusion connecting section 26, and the first fusion connecting section 26 is an annular structure extending along a circumferential direction of the inner surface of the housing 21, so that the second connecting section 233 is sealed to the housing 21 to block the opening of the housing 21 and seal the cavity inside the housing 21.

[0210] The end of the housing 21, which is located at the opening, can also be provided with a curved section 212, wherein the curved section 212 is bent to extend towards the electrode assembly 22, and part of the second connecting section 233 extends into a gap defined between the housing 21 and the curved section 212, and a sealing ring 27 is also mounted in the gap.

[0211] Finally, it should be noted that the above embodiments serve only to illustrate and not to limit the technical solutions of the present application. Although the present application has been described in detail with reference to the above various embodiments, those skilled in the art should understand that the technical solutions specified in the above various embodiments may still be modified, or some or all of the technical features contained therein may be replaced with equivalent ones; and such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present application, which are intended to fall within the scope of the claims and the description of the present application.In particular, the technical features mentioned in the various embodiments can be combined in any way, as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

[1] Battery cell, comprising: an electrode assembly with a first arrester; a housing defining a receiving space and an opening located at one end of the receiving space, the receiving space being used to receive the electrode assembly; and a current-collecting end cover that is firmly connected to the housing, wherein the current-collecting end cover seals the opening in the housing and the current-collecting end cover is electrically connected to the first surge arrester. [2] Battery cell according to claim 1, wherein the current-collecting end cover is welded to the housing, so that the current-collecting end cover is electrically conductively connected to the housing. [3] Battery cell according to claim 1 or 2, wherein the housing comprises a main body section and a weld section, wherein the main body section surrounds an outside of the electrode assembly and the weld section is arranged at one end of the main body section near the opening, and wherein the current-collecting end cap is welded to the weld section to form a first fusion section. [4] Battery cell according to claim 3, wherein the current-collecting end cap comprises: a first connecting section that is electrically connected to the first surge arrester; and a second connecting section which is connected to the first connecting section, wherein the second connecting section is welded to the welded section of the housing to form the first fusion connecting section. [5] Battery cell according to claim 4, wherein the second connecting section surrounds an outer edge of the first connecting section and projects in a direction away from the electrode assembly. [6] Battery cell according to claim 5, wherein an end surface on a side of the second connecting section, which is away from the first connecting section, is flush with an end surface on a side of the weld section, which is away from the main body section, such that the second connecting section and the weld section form the first fusion connecting section by butt welding at the flush end surfaces. [7] Battery cell according to claim 5, wherein the first fusion section is configured such that a laser penetrates the second fusion section in a direction that intersects an axis of the electrode assembly and melts the weld section at least partially to form the first fusion section. [8] Battery cell according to claim 7, wherein the first fusion section does not penetrate the weld section. [9] Battery cell according to claim 7 or 8, wherein the second connecting section has a thickness t1 in a direction perpendicular to a central axis of the electrode assembly and the second connecting section has a height h0 in an axial direction of the electrode assembly, wherein t1 and h0 satisfy the following: 2 ≤ h0 / t1 ≤ 6. [10] Battery cell according to one of claims 7 to 9, wherein the second connecting section has a thickness of t1 in a direction perpendicular to the central axis of the electrode assembly, wherein t1 ≤ 0.1mm ≤ t1 ≤ 0.5mm. [11] Battery cell according to one of claims 4 to 10, wherein an outer surface of the second connecting section is in a press fit with an inner surface of the welded section. [12] Battery cell according to claim 11, wherein the second connection section comprises a plurality of first projecting sections provided at intervals and projecting in a direction away from the electrode assembly, and second projecting sections located between two adjacent first projecting sections, wherein the height of the second projecting sections in the axial direction of the electrode assembly is less than the height of the first projecting sections, and wherein the first projecting sections and the second projecting sections are separately welded to the weld section to form part of the first fusion connection section. [13] Battery cell according to claim 12, wherein a plurality of second foregoing sections are uniformly distributed around the central axis of the electrode assembly. [14] Battery cell according to one of claims 4 to 13, wherein an inner diameter of the main body section is smaller than an inner diameter of the welded section, such that a step surface is formed at the connection of an inner surface of the main body section with an inner surface of the welded section, against which the current-collecting end cover rests. [15] Battery cell according to claim 14, wherein the wall thickness of the main body section is equal to the wall thickness of the welded section. [16] Battery cell according to claim 14, wherein an outer surface of the main body section is coplanar with an outer surface of the welded section. [17] Battery cell according to any one of claims 13 to 16, wherein the difference between an inner diameter of the weld section and an inner diameter of the main body section is greater than or equal to 0.1 mm. [18] Battery cell according to any one of claims 4 to 17, wherein the housing further comprises a curved section which is connected to an end of the welded section which is away from the main body section and is bent towards an inside of the welded section, such that a gap is formed between the curved section and the welded section in which at least part of the second connecting section is located. [19] Battery cell according to claim 18, wherein the battery cell further comprises a sealing ring, wherein the sealing ring is located within the gap and is arranged at least partially between the second connecting section and the bent section. [20] Battery cell according to claim 19, wherein the curved section comprises a connecting edge and an annular edge, the annular edge being connected to the welded section of the housing via the connecting edge and an end of the annular edge being remote from the connecting edge being close to the electrode assembly, and the sealing ring comprising a first sealing body and a second sealing body being connected to each other, the first sealing body being arranged between the second connecting section and the annular edge and the second sealing body being arranged between a side of the second connecting section opposite the electrode assembly and the connecting edge. [21] Battery cell according to claim 20, wherein the first sealing body comprises a first surface facing the second connecting section and a second surface facing the annular edge, wherein at least one of the first surface and the second surface is provided with a third projecting section. [22] Battery cell according to claim 21, wherein the third foregoing section has a width a in the axial direction of the electrode assembly and a height b in a direction perpendicular to the axial direction of the electrode assembly, wherein a and b satisfy the following: 0.5 mm ≤ a ≤ 2 mm, and 0.2 mm ≤ b ≤ 0.5 mm. [23] Battery cell according to any one of claims 4 to 22, wherein the first connecting section is welded to the first conductor to form a second fusion connecting section. [24] Battery cell according to claim 23, wherein the first connecting section comprises a first side surface facing the electrode assembly and a second side surface facing away from the electrode assembly, wherein the first side surface and / or the second side surface is provided with at least one reinforcing rib projecting from a surface and designed to reinforce the current-collecting end cap. [25] Battery cell according to claim 24, wherein at least a part of the reinforcing rib located on the first side surface is welded to the first conductor to form the second fusion section. [26] Battery cell according to claim 25, wherein the reinforcing rib provided for forming the second fusion section is designed as a stamped groove, wherein a side of the stamped groove facing away from the electrode assembly is recessed into a second side surface of the first fusion section. [27] Battery cell according to one of claims 23 to 26, wherein the second fusion section is arranged at uniform intervals along a circumferential direction of a center of the first fusion section. [28] Battery cell according to claim 27, wherein the second fusion section is formed by a plurality of radially extending spoke-like patterns or by a plurality of crescent-shaped patterns. [29] Battery cell according to any one of claims 4 to 28, wherein the first connection section comprises a drain connection section and a pressure relief section, wherein the drain connection section is welded to the first drain to form a second fusion connection section, and the pressure relief section is configured to relieve internal pressure of the battery cell when the internal pressure or temperature of the battery cell reaches a threshold. [30] Battery cell according to claim 29, wherein the drain connection section surrounds an outer surface of the pressure relief part. [31] Battery cell according to claim 29, wherein the drain connection section and the pressure relief section are provided in a one-piece formed manner. [32] Battery cell according to any one of claims 29 to 31, wherein the pressure relief section comprises a grooved groove, wherein the grooved groove is configured to tear along the grooved groove to release the internal pressure of the battery cell when the internal pressure or temperature of the battery cell reaches the threshold. [33] Battery cell according to claim 32, wherein the grooved groove is located on a surface of the first connecting member which faces the electrode assembly. [34] Battery cell according to claim 32 or 33, wherein the grooved groove is an annular groove centered in a center of the first connecting section. [35] Battery cell according to claim 34, wherein a central angle ∝ corresponding to the grooved groove has a value range of 270° ≤∝≤ 330°. [36] Battery cell according to one of claims 32 to 35, wherein the first connecting section further comprises a central area, wherein the central area is a projection area of ​​a central hole of the electrode assembly on the first connecting section; and the grooved groove is located on the circumference of the central area. [37] Battery cell according to claim 36, wherein the central area is a circular area and the grooved groove is an annular groove centered in a center of the first connecting section, wherein the central area has a diameter of d1 and the grooved groove has a minimum diameter of d2, wherein d2d1≤4. [38] Battery cell according to claim 36 or 37, wherein the current collector connection section is provided with at least one stamped groove which is welded to the first current collector to form the second fusible connection section, wherein the grooved groove is located between the current collector connection section and the central area. [39] Battery cell according to claim 38, wherein the first connection section is circular, the second fusion connection section has a maximum diameter of d3 and the first connection section has a diameter of d4, wherein the maximum diameter of the second fusion connection section is the diameter of a circle on which an endpoint of the second fusion connection section lies that is furthest from the center of the first connection section, and d3 < d4. [40] Battery cell according to claim 39, wherein the central area is a circular area centered in the middle of the first connection section, and the grooved groove is an annular groove centered in the middle of the first connection section, and the central area has a diameter of d1; the grooved groove has a diameter of d2; the fusion connection area has an outer diameter of d3; and the first connection section has a diameter of d4, wherein the following is satisfied: 0.8≤d42−d32d22−d12≤1.

2. [41] Battery cell according to one of claims 29 to 40, wherein the current collector connection section of the first connection section has a minimum thickness of t3 in the axial direction of the electrode assembly, the material of the current-collecting end cap has a Young's modulus of E and the electrode assembly has a weight of W, wherein t3×EW≥7000mm−1. [42] Battery cell according to one of claims 1 to 41, wherein at least one of two opposing surfaces of the current-collecting end cover and the housing is provided with a paste mask layer. [43] Battery cell according to claim 42, wherein the material of the first material layer is copper, the material of the second material layer is carbon steel and the material of the paste mask layer is nickel. [44] Battery cell according to one of claims 42 to 43, wherein a surface of the current-collecting end cover is provided with a first paste mask layer and a surface of the housing is provided with a second paste mask layer, wherein the first paste mask layer has a thickness of u1 and the second paste mask layer has a thickness of u2, wherein 1um ≤ u1 + u2 ≤ 9um. [45] Battery cell according to any one of claims 1 to 44, wherein the electrode assembly further comprises a second arrester having a polarity different from that of the first arrester; and wherein the battery cell further comprises electrode terminals, the electrode terminals being located at an end of the housing that is away from the opening and being electrically connected to the second arrester. [46] Battery comprising a battery cell according to any one of claims 1 to 45. [47] Electrical device, wherein the electrical device comprises a battery according to claim 46, wherein the battery is used to provide electrical energy.

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