End cover assembly, battery monomer and use method of end cover assembly

Abstract

The embodiment of the invention provides an end cover assembly, a battery monomer and a use method of the end cover assembly, the end cover assembly comprises an end cover body and an insulating layer, the end cover body is provided with a first side surface and a second side surface which are opposite to each other along the thickness direction of the end cover body, and a peripheral surface connected with the first side surface and the second side surface; the insulating layer is arranged on the first side surface; wherein the first side face comprises a coating area provided with the insulating layer and a blank area not provided with the insulating layer, and the blank area is located between the coating area and the peripheral face.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to an end cap assembly, a battery cell, and a method of using the end cap assembly. Background Technology

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0003] Batteries are widely used in portable electronic devices, electric vehicles, power tools, drones, energy storage devices, and other fields. Improving the reliability of individual battery cells and the battery itself is a pressing issue in battery technology. Summary of the Invention

[0004] This application provides an end cap assembly, a battery cell, and a method of using the end cap assembly, which can improve the reliability of the battery cell and the battery.

[0005] This application is achieved through the following technical solution:

[0006] In a first aspect, embodiments of this application provide an end cap assembly for a battery cell. The end cap assembly includes an end cap body and an insulating layer. The end cap body has a first side and a second side opposite to each other along its thickness direction, and an outer peripheral surface connecting the first side and the second side. The insulating layer is disposed on the first side. The first side includes a coated area on which the insulating layer is disposed and a blank area on which the insulating layer is not disposed, and the blank area is located between the coated area and the outer peripheral surface.

[0007] According to the end cap assembly of this application embodiment, an insulating layer is provided in the coating area on the end cap body. This layer provides insulation protection for the first side of the end cap body, effectively mitigating the corrosion problem of the electrolyte on the end cap body and improving the reliability of the battery cell. Simultaneously, the presence of the blank area ensures that the insulating layer does not obstruct the connection between the end cap body and the housing, guaranteeing a smooth connection between them without affecting the connection strength and effectiveness. Furthermore, it reduces the impact of the high temperature generated during the connection between the end cap body and the housing on the insulating layer, thereby improving the insulation protection effect of the insulating layer.

[0008] According to some embodiments of this application, the insulating layer includes a body portion and a thickened portion, the thickened portion being closer to the blank area than the body portion; wherein, along the thickness direction of the end cap body, the thickness of the thickened portion is greater than the thickness of the body portion.

[0009] In the above scheme, since the blank area is set so as not to affect the smooth connection between the end cap body and the housing, after the end cap body and the housing are connected, if the insulation layer is a normal insulation layer, that is, an insulation layer that does not melt after the battery cell is heated, the insulation layer can ensure that the part of the first side facing the internal space of the housing has better insulation ability, thereby reducing the probability of the end cap body being corroded by the electrolyte.

[0010] If the insulating layer can melt after the battery cell is heated, the amount of molten material in the thickened part increases, allowing it to flow better into the connection area between the end cap body and the housing. This enables the end cap body and the housing to achieve a primary seal not only through their fixed connection area, but also allows the molten insulating layer to flow to the inner circumferential surface of the housing and even to the fixed connection area between the end cap body and the housing. After the molten insulating material cools, the insulating layer achieves a secondary seal between the end cap body and the housing.

[0011] According to some embodiments of this application, the thickened portion has a first side adjacent to the main body and a second side adjacent to the blank area, and the thickness of the thickened portion gradually increases from the first side to the second side.

[0012] In the above scheme, after the battery cell is heated, the thickened part melts, and the thicker part can flow more quickly to the blank area and reach the inner circumferential surface of the shell, and even reach the fixed connection area between the end cap body and the shell; at the same time, since the thickness of the thickened part far away from the blank area is relatively thin, after the thickened part melts and flows to the inner circumferential surface of the shell or the fixed connection area between the end cap body and the shell, the overall thickness of the insulating layer is roughly the same.

[0013] Of course, if the insulating layer does not melt when the battery cell is heated, the gradually thickened portion can gradually enhance the insulation performance of the insulating layer near the inner circumferential surface, ensuring that the edge area of ​​the first side has sufficient insulation performance, and further reducing the risk of the end cap body being corroded by the electrolyte.

[0014] According to some embodiments of this application, the thickness of the thickened portion is t, and satisfies: 0mm < t ≤ 5mm.

[0015] In the above scheme, since the thickness of the thickened part meets the above range, the thickened part can have a sufficient amount of molten material, so that the molten material can flow to the inner circumferential surface of the shell or even the fixed connection area between the end cap body and the shell. At the same time, the thickness of the thickened part will not be too large to affect the energy density of the battery cell.

[0016] Of course, if the insulating layer does not melt when the battery cell is heated, and the thickness of the thickened part meets the above conditions, it can ensure that the area of ​​the insulating layer near the inner circumference of the casing has sufficient insulation performance, and at the same time ensure that the thickness of the insulating layer near the inner circumference of the casing is not too high, so as not to have a negative impact on the energy density of the battery cell.

[0017] According to some embodiments of this application, the thickened portion is disposed around the body portion.

[0018] In the above scheme, it can be ensured that after the insulation layer melts, the thickened part has enough molten material to flow to the circumferential area of ​​the inner circumferential surface of the shell, ensuring that the inner circumferential surface of the shell can be sealed by the insulation layer. Thus, after the battery cell is heated and then cooled, the circumferential sealing of the connection area between the end cap body and the shell is improved, and the risk of the end cap body being corroded by the electrolyte is also reduced.

[0019] When the insulation layer does not melt after the battery cell is heated, the thickened portion can improve the insulation performance of the insulation layer in the entire circumferential area, further reducing the risk of the end cap body being corroded by the electrolyte.

[0020] According to some embodiments of this application, the blank area is an annular region surrounding the coated area.

[0021] In the above solution, when the end cap body is fixedly connected to the housing, the connection between the end cap body and the housing will not be affected by the insulating material provided on the circumferential edge of the first side, thereby ensuring that the sealing performance between the end cap body and the housing is improved.

[0022] According to some embodiments of this application, the area of ​​the first side is S, and the area of ​​the side of the insulating layer facing the inside of the battery cell is S1, satisfying: 13% ≤ S1 / S ≤ 99%.

[0023] In the above scheme, when the insulating layer does not melt when the battery cell is heated, on the one hand, it can make the first side have a large insulating area, and on the other hand, it can also prevent the first side from being completely covered by the insulating layer. The edge area of ​​the first side has a blank area, so that the insulating layer will not affect the connection strength and connection effect between the end cap body and the shell.

[0024] When the insulating layer can melt during the heating of the battery cell, on the one hand, the insulating layer can have a sufficient amount of material flowing to the inner circumferential surface of the shell after melting, and can even reach the fixed connection area between the end cap body and the shell. On the other hand, when the end cap body and the shell are connected, the first side is not completely covered by the insulating layer, and the edge area of ​​the first side has a blank area, so that the insulating layer will not affect the connection strength and connection effect between the end cap body and the shell.

[0025] According to some embodiments of this application, the width of the blank area is D, which satisfies 0.5mm≤D≤5mm.

[0026] In the above solution, on the one hand, when the end cap body is connected to the housing, the negative impact of the insulating layer on the connection effect can be reduced. On the other hand, when the battery cell is heated, if the insulating layer can melt, the molten insulating material can more easily coat the blank area and flow to the inner circumferential surface of the housing. When the battery cell is heated, if the insulating layer does not melt, it can ensure that more areas of the first side are covered by the insulating layer.

[0027] According to some embodiments of this application, at least a portion of the blank area is constructed as a guide slope, and the guide slope is not on the same plane as the coating area.

[0028] In the above scheme, when the end cap assembly is located below the battery cell, and the battery cell is heated, the insulating layer melts. The molten insulating material on the coating area can flow downward through the guide ramp under the action of gravity and move to the inner circumferential surface of the shell or even the fixed connection area between the end cap body and the shell.

[0029] According to some embodiments of this application, the angle between the guide ramp and the outer peripheral surface is an obtuse angle.

[0030] In the above scheme, on the one hand, the flow of molten material on the guide slope can be smoother, and on the other hand, the thickness of the edge area of ​​the end cap body can be prevented from being too small, thus preventing a significant reduction in the structural strength of the end cap body.

[0031] According to some embodiments of this application, the guide ramp surrounds the coating area.

[0032] In the above scheme, when the battery cell is heated and the insulating layer can melt, the insulating layer can move more evenly to the inner circumferential surface of the casing, improving the sealing performance between the end cap body and the casing. When the battery cell is heated but the insulating layer does not melt, the guide slope can surround the coating area, further reducing the material requirements of the end cap body and lowering its manufacturing cost.

[0033] According to some embodiments of this application, the blank area is provided with a first groove, one end of the first groove extends to the outer peripheral surface, and at least a portion of the bottom surface of the first groove is constructed as the guide slope.

[0034] In the above scheme, the first groove can guide the molten insulating material on the coating area to the inner circumferential surface of the shell, and can store a certain amount of molten insulating material. Therefore, the area coated with insulating material on the inner circumferential surface of the shell that is directly opposite the first groove is larger than the height of other areas coated with insulating material on the inner circumferential surface, thereby improving the sealing effect between the end cap body and the shell to at least a certain extent.

[0035] Because the blank area is not entirely sloping, the flow of molten material is more concentrated, and the molten material can more easily reach the inner circumference of the shell through the first groove. This reduces the likelihood that the molten material will have difficulty flowing to the inner circumference of the shell due to the large area of ​​the blank area.

[0036] If the insulation layer of the battery cell does not melt when heated, setting a first groove in the blank area can significantly reduce the material used in the end cover body and reduce the manufacturing cost of the end cover assembly.

[0037] According to some embodiments of this application, there are multiple first grooves, and the multiple first grooves are arranged at intervals around the coating area.

[0038] In the above scheme, after the insulation layer melts, the molten material on the coating area can flow evenly to the inner circumferential surface of the shell, which improves the sealing uniformity between the end cap body and the inner circumferential surface of the shell.

[0039] When the battery cell is heated and the insulating layer does not melt, multiple first grooves can be set in the blank area to further reduce the material used in the end cap body and reduce the manufacturing cost of the end cap assembly.

[0040] According to some embodiments of this application, the edge of the coating area is provided with a second groove, and the end of the first groove away from the outer peripheral surface is connected to the second groove.

[0041] In the above scheme, after the battery cell is heated, the amount of material after the insulation layer in the second groove melts can support its flow to the inner circumferential surface of the shell, preventing the electrolyte from directly contacting the welding area between the end cap body and the shell, reducing the probability of the welding area being corroded by the electrolyte, thereby reducing the probability of leakage due to welding area failure, and ensuring good sealing performance between the end cap body and the shell.

[0042] When the battery cell is heated and the insulating layer does not melt, the material used in the end cap body can be further reduced by setting a second groove, thereby reducing the manufacturing cost of the end cap assembly.

[0043] According to some embodiments of this application, the bottom surface of the first groove is connected to the bottom surface of the second groove and the outer peripheral surface.

[0044] In the above scheme, the portion of the insulating layer located in the second groove can easily flow through the bottom surface of the first groove and reach the outer peripheral surface or the inner peripheral surface of the casing after the battery cell is heated and melted, and can even reach the gap between the end cap body and the casing.

[0045] The molten insulating material can flow from the first side to the inner circumferential surface of the housing, and even into the gap between the end cap body and the inner circumferential surface of the housing.

[0046] According to some embodiments of this application, the second groove is an annular groove provided along the edge of the coating area.

[0047] In the above scheme, the portion of the insulating layer in the second groove can have a sufficient amount of material after melting, and can then be coated circumferentially on the inner surface of the shell, thereby further improving the sealing performance between the end cap body and the shell.

[0048] According to some embodiments of this application, the included angle between the guide slope and the coating area is α, which satisfies: 100°≤α≤160°.

[0049] In the above scheme, since the included angle between the guide slope and the coating area meets the above range, on the one hand, the insulating layer of the coating area can flow to the inner circumferential surface of the shell more easily after melting, and on the other hand, the tilt angle to the guide slope is not too large, which would result in poor structural strength of the outer periphery of the end cap body.

[0050] If the insulating layer does not melt after the battery cell is heated, since the angle between the guide slope and the coating area meets the above range, on the one hand, the weight of the end cap body and the manufacturing cost of the end cap body can be reduced, and on the other hand, the structural strength of the outer periphery of the end cap body will not be poor.

[0051] According to some embodiments of this application, the melting point of the insulating layer is greater than or equal to 85°C and less than or equal to 120°C.

[0052] In the above scheme, after the end cap body is connected to the housing, on the one hand, the insulating layer can melt when the battery cell is heated, so that the molten insulating material can flow through the blank area and coat the blank area, and then reach the inner circumferential surface of the housing, as well as the fixed connection area between the housing and the end cap body, to perform secondary sealing of the housing and end cap body of the battery cell. On the other hand, the insulating layer will not melt during normal use due to its low melting point, thus improving the stability of the insulating layer.

[0053] According to some embodiments of this application, the melting point of the insulating layer is greater than or equal to 90°C and less than or equal to 110°C.

[0054] In the above scheme, after the end cap body is connected to the housing, on the one hand, the insulating layer can melt more easily when the battery cell is heated, so the molten insulating material can flow more easily through the blank area and coat the blank area, and then reach the inner circumferential surface of the housing, as well as the fixed connection area between the housing and the end cap body, to perform secondary sealing of the battery cell housing and the end cap body. On the other hand, the insulating layer will not melt during normal use due to its low melting point, which further improves the stability of the insulating layer.

[0055] According to some embodiments of this application, the insulating layer includes one of paraffin wax, rosin, PE wax, polyolefin, stearic acid, and white oil.

[0056] In the above scheme, the insulating layer can be melted after the battery cell is heated, and the molten insulating material can flow to the inner circumferential surface of the shell to perform a secondary seal between the end cap body and the shell.

[0057] Secondly, embodiments of this application provide a battery cell including the aforementioned end cap assembly.

[0058] According to the embodiments of this application, the battery cell is provided with the above-mentioned end cap assembly. Therefore, after the end cap assembly is connected to the housing, the insulating layer can effectively reduce the risk of the end cap body being corroded by the electrolyte. At the same time, due to the existence of the blank area, the connection effect between the end cap body and the housing will not be affected.

[0059] Thirdly, embodiments of this application provide a method of using the above-mentioned end cap assembly, including:

[0060] The end cap assembly is placed over the opening of the housing, such that the insulating layer faces the interior of the housing;

[0061] The end cap body and the housing are connected to form an assembly;

[0062] The assembly is heated to melt the insulating layer and allow it to diffuse into the blank area;

[0063] The assembly is cooled to cure the insulating layer.

[0064] According to the usage method of the end cap assembly in this application embodiment, when the end cap body is connected to the housing, the presence of the blank area ensures that the insulating layer does not obstruct the connection between the end cap body and the housing, guaranteeing a smooth connection between them without affecting the connection strength and effect. Simultaneously, the molten insulating layer can diffuse into the blank area, thus completely covering the side of the end cap body facing inwards from the housing, reducing the probability of contact between the electrolyte and the end cap body, and effectively reducing the risk of corrosion of the end cap body by the electrolyte.

[0065] After the end cap assembly and the housing are assembled together to form an assembly, the assembly is heated. At this time, the insulation layer melts, and the molten insulation material can also diffuse to the inner circumferential surface of the housing. Thus, not only can the end cap body and the housing be sealed at first, but the solidified insulation material can also extend to the inner circumferential surface of the housing, thereby providing a secondary seal between the end cap body and the housing. This further improves the sealing performance of the battery cell, further reduces the risk of electrolyte leakage in the battery cell, and improves the reliability of the battery cell.

[0066] According to some embodiments of this application, when the assembly is heated, the end cap assembly is oriented downwards.

[0067] In the above scheme, the molten insulating material on the coating area can flow towards the blank area or even the inner circumferential surface of the shell under the action of gravity. Thus, after cooling, the insulating layer can diffuse to the blank area and the inner circumferential surface of the shell, effectively reducing the risk of the end cap body being corroded by the electrolyte and achieving a secondary seal between the end cap body and the shell.

[0068] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0069] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0070] Figure 1 A schematic diagram of a vehicle provided in an embodiment of this application;

[0071] Figure 2 An exploded view of a battery provided in an embodiment of this application;

[0072] Figure 3 An exploded view of a single battery cell provided in an embodiment of this application;

[0073] Figure 4 This is a front view of the end cap assembly provided in an embodiment of this application;

[0074] Figure 5 A side view of the end cap assembly provided in an embodiment of this application;

[0075] Figure 6 A side view of an end cap assembly provided in another embodiment of this application;

[0076] Figure 7A side view of an end cap assembly provided in yet another embodiment of this application;

[0077] Figure 8 This is a side view of the end cap body provided in an embodiment of this application;

[0078] Figure 9 for Figure 8 Circle A shows a magnified view of the area provided;

[0079] Figure 10 A cross-sectional view of a battery cell provided in an embodiment of this application;

[0080] Figure 11 for Figure 10 A magnified view of circle B;

[0081] Figure 12 A flowchart illustrating a method for manufacturing a battery cell according to an embodiment of this application.

[0082] Icons: Vehicle 1000, Battery 100, Controller 200, Motor 300, Housing 10, Battery Cell 20, First Sub-Housing 11, Second Sub-Housing 12, Housing 21, Electrode Assembly 22, Electrode Terminal 25, Housing 211, End Cap Assembly 212, End Cap Body 212a, Insulating Layer 212b, First Side 101, Coated Area 101a, Blank Area 101b, Second Side 102, Outer Peripheral Surface 103, Body Part 212b1, Thickened Part 212b2, First Side a, Second Side b, Guide Inclined Surface 108, First Groove 104, Second Groove 105. Detailed Implementation

[0083] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0084] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0085] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0086] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0087] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0088] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0089] In some embodiments, the battery can be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0090] In some embodiments, the battery can be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0091] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0092] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0093] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0094] The battery cell may be, but is not limited to, lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc.

[0095] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0096] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0097] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0098] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0099] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used.

[0100] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0101] As an example, the negative electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, or made of carbon, nickel, or titanium, etc.

[0102] In some embodiments, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0103] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0104] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0105] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0106] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0107] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0108] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0109] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0110] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0111] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0112] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0113] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0114] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0115] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0116] In some implementations, the electrode assembly is a stacked structure.

[0117] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0118] In some embodiments, the housing includes an end cap and a casing, the casing having an opening, and the end cap closing the opening to form a sealed space for accommodating substances such as electrode assemblies and electrolytes. The casing may have one or more openings. The end cap may also be provided one or more times.

[0119] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab of the electrode assembly. The electrode terminal can be directly connected to the tab or indirectly connected to the tab via an adapter. The electrode terminal can be located on the end cap or on the housing.

[0120] In some implementations, an explosion-proof valve is provided on the housing. The explosion-proof valve is used to release the internal pressure of the battery cells.

[0121] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. There are no particular limitations in the embodiments of this application.

[0122] The battery mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity.

[0123] In some embodiments, the battery can be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0124] In some embodiments, the battery can be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0125] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0126] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0127] Batteries have outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide applicability, and low self-discharge coefficient, making them an important component of the current development of new energy.

[0128] The development of battery technology must take into account multiple design factors, such as energy density, discharge capacity, charge-discharge rate and other performance parameters. In addition, battery assembly efficiency also needs to be considered.

[0129] Please refer to Figure 3 , Figure 3 Exploded views of individual battery cells provided in some embodiments of this application. For example... Figure 3 As shown, the battery cell 20 includes a housing 21, an electrode assembly 22, and electrode terminals 25. The housing 21 includes a casing 211 and an end cap assembly 212. The casing 211 has an opening, and the end cap assembly 212 closes the opening to isolate the internal environment of the battery cell 20 from the external environment.

[0130] The housing 211 is a component used to cooperate with the end cap assembly 212 to form the internal environment of the battery cell 20, wherein the formed internal environment can accommodate the electrode assembly 22, electrolyte, and other components. The housing 211 and the end cap assembly 212 can be independent components. The housing 211 can have various shapes and sizes. Specifically, the shape of the housing 211 can be determined according to the specific shape and size of the electrode assembly 22. The housing 211 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, and plastic.

[0131] End cap assembly 212 refers to a component that covers the opening of housing 211 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap assembly 212 can be adapted to the shape of housing 211 to fit it. Optionally, end cap assembly 212 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap assembly 212 is less prone to deformation under pressure and impact, enabling battery cell 20 to have higher structural strength and improved reliability. Functional components such as electrode terminals can be provided on end cap assembly 212. Electrode terminals can be used for electrical connection with electrode assembly 22 to output or input electrical energy to battery cell 20. The material of end cap assembly 212 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose special limitations on this. In some embodiments, an insulating structure may also be provided inside the end cap assembly 212. The insulating structure can be used to isolate the electrical connection components within the housing 211 from the end cap assembly 212 to reduce the risk of short circuits. For example, the insulating structure may be made of plastic, rubber, etc.

[0132] Electrode assembly 22 is the component in the battery cell 20 where electrochemical reactions occur. The casing 211 may contain one or more electrode assemblies 22. The electrode assembly 22 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets to separate them and prevent internal short circuits. The portions of the positive and negative electrode sheets containing active material constitute the main body of the electrode assembly, while the portions without active material each constitute a tab. The positive and negative tabs may be located together at one end of the main body or separately at both ends. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs connect to the electrode terminals to form a current loop.

[0133] End caps are typically fixed to the housing to seal the openings on the housing, thereby isolating the internal and external spaces of the housing and creating a relatively sealed space inside the housing.

[0134] During the use of some batteries, it is necessary to assemble and use the individual battery cells upside down according to the customer's group assembly optimization requirements, with the end cap body located at the bottom. In this case, the side of the end cap body facing inwards from the battery cell can directly contact the electrolyte. Therefore, the electrolyte may corrode the end cap body, and may even cause leakage of the casing due to electrolyte corrosion.

[0135] While leakage from a single battery cell may affect its performance, it won't significantly impact the cell's safety. However, considering the overall system structure of the battery module or pack, electrolyte leakage can lead to electrolyte sparking and thermal runaway if a high-voltage circuit exists in that area.

[0136] According to an embodiment of this application, the end cap assembly 212 can be used on a battery cell 20. The end cap assembly 212 includes an end cap body 212a and an insulating layer 212b.

[0137] The end cap body 212a is generally made of a high-strength material. For example, the end cap body 212a can be a metal part, and similarly, the shell 211 can also be a metal part.

[0138] like Figures 4-7 As shown, the end cap body 212a can be generally plate-shaped, and the outer periphery of the end cap body 212a can be fixedly connected to the shell 211.

[0139] The end cap body 212a has a first side surface 101 and a second side surface 102, which are arranged opposite to each other along the thickness direction of the end cap body 212a.

[0140] The end cap body 212a also has an outer peripheral surface 103, which can connect the first side surface 101 and the second side surface 102 together.

[0141] The insulating layer 212b can be disposed on the first side 101. Generally speaking, after the end cap assembly 212 is installed on the housing 211, the first side 101 faces the receiving space of the housing 211. That is to say, the insulating layer 212b can be disposed on the inner surface of the end cap body 212a.

[0142] The first side surface 101 includes a coated area 101a and a blank area 101b. An insulating layer 212b is provided on the coated area 101a. The insulating layer 212b is not coated onto the blank area 101b. The blank area 101b is located between the coated area 101a and the outer peripheral surface 103.

[0143] The blank area 101b can be set in the edge area of ​​the first side 101. The blank area 101b can be the area of ​​the first side 101 of the end cap body 212a that is directly exposed and not covered by the insulating layer 212b.

[0144] Along the circumference of the first side 101, a portion of the edge region of the first side 101 can be a blank area 101b, and the entire edge region of the first side 101 can be a blank area 101b.

[0145] According to the end cap assembly 212 of this application embodiment, an insulating layer 212b is provided on the coating area 101a of the end cap body 212a. This insulating layer can provide insulation protection for a portion of the first side 101 of the end cap body 212a, effectively mitigating the corrosion problem of the electrolyte on the end cap body and improving the reliability of the battery cell 20. Simultaneously, due to the presence of the blank area 101b, the insulating layer 212b does not hinder the connection between the end cap body 212a and the housing 211, ensuring a smooth connection between them without affecting the connection strength and effect. Furthermore, it reduces the impact of the high temperature generated during the connection between the end cap body 212a and the housing 211 on the insulating layer 212b, thereby improving the insulation protection effect of the insulating layer 212b.

[0146] In some embodiments of this application, the end cap body 212a and the housing 211 can be fixed together by welding. There is a welding area between the end cap body 212a and the housing 211, and a primary seal can be achieved between the end cap body 212a and the housing 211 through this welding area.

[0147] The end cap body 212a and the housing 211 can be fixed together by adhesive bonding. There is an adhesive area between the end cap body 212a and the housing 211, and a one-time seal can be achieved between the end cap body 212a and the housing 211 through this adhesive area.

[0148] Of course, the end cap body 212a and the housing 211 in this embodiment of the application can be fixedly connected in other ways, and this application does not limit this.

[0149] It should be noted that the aforementioned welding or bonding areas can fix the end cap body 212a and the housing 211 together. In other words, the end cap body 212a and the housing 211 are mainly fixed together through the welding or bonding areas. The aforementioned welding or bonding areas can all be referred to as fixed connection areas.

[0150] According to some embodiments of this application, such as Figures 6-7 As shown, the insulating layer 212b includes a main body portion 212b1 and a thickened portion 212b2. The thickened portion 212b2 is closer to the blank area 101b than the main body portion 212b1. In other words, the portion of the insulating layer 212b closer to the blank area 101b has a larger thickness.

[0151] Since the blank area 101b is set so as not to affect the smooth connection between the end cap body 212a and the housing 211, after the end cap body 212a and the housing 211 are connected, if the insulating layer 212b is a normal insulating layer 212b, that is, an insulating layer 212b that does not melt after the battery cell 20 is heated, the insulating layer 212b can ensure that the part of the first side 101 facing the internal space of the housing 211 has better insulation ability, thereby reducing the probability of the end cap body 212b being corroded by the electrolyte.

[0152] If the insulating layer 212b is molten after the battery cell 20 is heated, the molten material in the thickened portion 212b2 increases, allowing it to flow better into the connection area between the end cap body 212a and the housing 211. This enables the end cap body 212a and the housing 211 to not only achieve a primary seal through the fixed connection area, but also allows the molten insulating layer 212b to flow into the inner circumferential surface of the housing 211, and even into the fixed connection area between the end cap body 212a and the housing 211 (e.g., the micropores of the weld). After the molten insulating material cools, the insulating layer 212b achieves a secondary seal between the end cap body 212a and the housing 211.

[0153] Therefore, when the end cap assembly 212 is facing downward, the electrolyte inside the housing 212 can be blocked not only by the insulating layer 212b covering the first side 101 and the inner peripheral surface of the housing 211 adjacent to the first side 101, but also by the fixed connection area between the end cap body 212a and the housing 211, thereby reducing the risk of electrolyte leakage.

[0154] In some embodiments of this application, such as Figure 7 As shown, the thickened portion 212b2 has a first side a and a second side b. The first side a is adjacent to the main body portion 212b1, and the second side b is adjacent to the blank area 101b. The thickness of the thickened portion 212b2 gradually increases from the first side a to the second side b.

[0155] As the name suggests, the first side a and the second side b are spaced apart, thus ensuring that the thickened part 212b2 has a certain width.

[0156] From the first side a to the second side b, the thickness of the thickened portion 212b2 gradually increases. That is, the thickness of the thickened portion 212b2 near the blank area 101b is greater than the thickness of the thickened portion 212b2 away from the blank area 101b. As a result, when the battery cell 20 is heated, the thickened portion 212b2 melts, and the thicker part of the thickened portion 212b2 can flow more quickly to the blank area 101b and reach the inner circumferential surface of the housing 211, and even reach the fixed connection area between the end cap body 212a and the housing 211. At the same time, since the thickness of the thickened portion 212b2 away from the blank area 101b is relatively thin, after the thickened portion 212b2 melts and flows to the inner circumferential surface of the housing 211 or the fixed connection area between the end cap body 212a and the housing 211, the overall thickness of the insulating layer 212b is approximately the same.

[0157] Of course, if the insulating layer 212b does not melt when the battery cell 20 is heated, the gradually thickened portion 212b2 can gradually enhance the insulation performance of the insulating layer 212b near the inner circumferential surface, ensuring that the edge area of ​​the first side 101 has sufficient insulation performance, and further reducing the risk of the end cap body 212b being corroded by the electrolyte.

[0158] In some embodiments of this application, such as Figure 6 As shown, the thickness of the thickened portion 212b2 is t, which satisfies: 0mm < t ≤ 5mm. For example, the thickness of the thickened portion 212b2 can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, or 5mm, etc.

[0159] The thickness of the thickened portion 212b2 described above is only a few specific examples of this application. As long as the thickness of the thickened portion 212b2 meets the above range, it is within the protection scope of this application.

[0160] Since the thickness of the thickened portion 212b2 meets the above-mentioned range, the thickened portion 212b2 can have a sufficient amount of molten material, so that the molten material can flow to the inner peripheral surface of the shell 211 or even the fixed connection area between the end cap body 212a and the shell 211. At the same time, the thickness of the thickened portion 212b2 will not be too large to affect the energy density of the battery cell 20.

[0161] Of course, if the insulating layer 212b does not melt when the battery cell 20 is heated, and the thickness of the thickened portion 212b2 meets the above conditions, on the one hand, it can ensure that the area of ​​the insulating layer 212b near the inner circumferential surface of the shell 211 has sufficient insulation performance, and on the other hand, it can ensure that the thickness of the area of ​​the insulating layer 212b near the inner circumferential surface of the shell 211 is not too high and thus has a negative impact on the energy density of the battery cell 20.

[0162] In some embodiments of this application, such as Figures 6-7 As shown, the thickened portion 212b2 is provided around the body portion 212b1. That is, the entire circumferential edge of the insulating layer 212b is the thickened portion 212b2, which ensures that after the insulating layer 212b melts, the thickened portion 212b2 has sufficient molten material to flow to the circumferential area of ​​the inner circumferential surface of the shell 211. This ensures that the circumferential area of ​​the inner circumferential surface of the shell 211 can be sealed by the insulating layer 212b, thereby improving the circumferential sealing of the connection area between the end cap body 212a and the shell 211 after the battery cell 20 is heated and then cooled, and also reducing the risk of the end cap body 212a being corroded by the electrolyte.

[0163] If the insulating layer 212b does not melt after the battery cell 20 is heated, the thickened portion 212b2 can improve the insulation performance of the insulating layer 212b in the entire circumferential area, further reducing the risk of the end cap body 212a being corroded by the electrolyte.

[0164] According to some embodiments of this application, such as Figure 4 As shown, the blank area 101b is an annular region surrounding the coating area 101a. That is, the entire circumferential edge of the first side surface 101 is not coated with insulating material. Therefore, when the end cap body 212a is fixedly connected to the housing 211, the connection between the end cap body 212a and the housing 211 will not be affected by the insulating material on the circumferential edge of the first side surface 101, thus ensuring improved sealing between the end cap body 212a and the housing 211.

[0165] In some embodiments of this application, the area of ​​the first side 101 is S, and the area of ​​the side of the insulating layer 212b facing the internal space of the battery cell 20 is S1, satisfying: 13% ≤ S1 / S ≤ 99%. For example, the ratio S1 / S of the area of ​​the first side 101 to the area of ​​the side of the insulating layer 212b facing the internal space of the battery cell 20 can be 13%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99%.

[0166] The ratio of the area of ​​the first side 101 to the side area of ​​the insulating layer 212b facing the internal space of the battery cell 20 is only a specific embodiment of this application, and any ratio that satisfies the above range is within the protection scope of this application.

[0167] In this embodiment, the ratio of the area of ​​the first side 101 to the side area of ​​the insulating layer 212b facing the internal space of the battery cell 20 satisfies the above-mentioned range. When the battery cell 20 is heated without melting, the insulating layer 212b can, on the one hand, make the first side 101 have a large insulating area, reducing the risk of the end cap body 212a being corroded by the electrolyte. On the other hand, it also prevents the first side 101 from being completely covered by the insulating layer 212b. The edge area of ​​the first side 101 has a blank area 101b, so that the insulating layer 212b will not affect the connection strength and connection effect between the end cap body 212a and the shell 211.

[0168] When the insulating layer 212b can melt during the heating of the battery cell 20, on the one hand, the insulating layer 212b can have sufficient material to coat the blank area 101b after melting, flow to the inner circumferential surface of the housing 211, and even reach the fixed connection area between the end cap body 212a and the housing 211, thereby reducing the risk of the end cap body 212a being corroded by the electrolyte. On the other hand, when the end cap body 212a and the housing 211 are connected, the first side 101 is not completely covered by the insulating layer 212b. The edge area of ​​the first side 101 has a blank area 101b, so the insulating layer 212b will not affect the connection strength and connection effect between the end cap body 212a and the housing 211.

[0169] According to one embodiment of this application, such as Figure 5 As shown, the width of the blank area 101b is D, which satisfies: 0.5mm≤D≤5mm. For example, the thickness of the blank area 101b can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm, etc.

[0170] The thickness of the blank area 101b described above are just some specific examples of this application. Any thickness value of the blank area 101b that falls within the above range is within the protection scope of this application.

[0171] Since the blank area 101b meets the above-mentioned range, on the one hand, when the end cap body 212a is connected to the housing 211, the negative impact of the insulating layer 212b on the connection effect can be reduced. On the other hand, when the battery cell 20 is heated, if the insulating layer 212b can melt, the molten insulating material can more easily coat the blank area 101b and flow to the inner circumferential surface of the housing 211. When the battery cell 20 is heated, if the insulating layer 212b does not melt, it can be ensured that more areas of the first side 101 are covered by the insulating layer 212b.

[0172] In some embodiments of this application, at least a portion of the blank area 101b is constructed as a guide slope 108, meaning that the guide slope 108 is not on the same plane as the coating area 101a, but rather the guide slope 108 is inclined relative to the coating area 101a. The guide slope 108 is adapted to guide the molten material of the insulating layer 212b into the outer peripheral surface 103.

[0173] The angle between the guide slope 108 and the outer peripheral surface 103 is an obtuse angle, meaning that the guide slope 108 is inclined toward the second side surface 102. Therefore, when the end cap assembly 212 is below the battery cell 20, and the battery cell 20 is heated, the insulating layer 212b melts. The molten insulating material on the coating area 101a can flow downwards through the guide slope 108 under the influence of gravity, moving to the inner peripheral surface of the housing 211 or even the fixed connection area between the end cap body 212a and the housing 211.

[0174] In addition, on the one hand, it can make the flow of molten material on the guide slope 108 smoother, and on the other hand, it can ensure that the thickness of the edge area of ​​the end cap body 212a is not too small, so as not to significantly reduce the structural strength of the end cap body 212a.

[0175] If the insulating layer 212b does not melt after the battery cell 20 is heated, the guide slope 108 in the blank area 101b can significantly reduce the material cost of the end cap assembly 212.

[0176] For example, the guide slope 108 has a first end away from the outer peripheral surface 103 and a second end close to the outer peripheral surface 103. If the second side surface 102 is a relatively flat plane, the distance between the guide slope 108 and the second side surface 102 gradually decreases from the first end to the second end.

[0177] In some embodiments of this application, the guide slope 108 can be a plane or an arc surface, as long as the distance between the guide slope 108 and the second side surface 102 gradually decreases from the first end to the second end.

[0178] In some embodiments of this application, such as Figure 8 As shown, the guide slope 108 can surround the coating area 101b. Therefore, when the battery cell 20 is heated and the insulating layer 212b can melt, the insulating layer 212b can move more evenly to the inner circumferential surface of the housing 20, improving the seal between the end cap body 212a and the housing 20. When the battery cell 20 is heated and the insulating layer 212b does not melt, the guide slope 108 can surround the coating area 101b, further reducing the material requirements of the end cap body 212a and lowering its manufacturing cost.

[0179] According to some embodiments of this application, such as Figure 9 As shown, the blank area 101b is provided with a first groove 104, one end of which extends to the outer peripheral surface 103. At least a portion of the bottom surface of the first groove 104 is constructed as a guide slope 108. That is to say, the blank area 101b is not made entirely into an inclined slope, but a portion of the blank area 101b is recessed toward the second side surface 102, thereby forming the first groove 104.

[0180] The first groove 104 can guide the molten insulating material on the coating area 101a to the inner circumferential surface of the housing 211. The first groove 104 can store a certain amount of molten insulating material. Therefore, the area coated with insulating material on the inner circumferential surface of the housing 211 that is directly opposite the first groove 104 is larger than the height of the area coated with insulating material on other areas of the inner circumferential surface, thereby improving the sealing effect between the end cap body 212a and the housing 211 to at least a certain extent.

[0181] It is understood that the area on the inner circumferential surface of the housing 211 that is not directly opposite the first groove 104 has a gap between it and the end cap body 212a that communicates with the first groove 104. The molten material flowing out from the first groove 104 coats the area on the inner circumferential surface of the housing 211 that is not directly opposite the first groove 104 through this gap.

[0182] Since the blank area 101b is not entirely an inclined surface, the flow of molten material is more concentrated, and the molten material can more easily reach the inner circumferential surface of the shell 211 through the first groove 104. This reduces the likelihood that the molten material will not easily flow to the inner circumferential surface of the shell 211 due to the large area of ​​the blank area 101b.

[0183] If the insulating layer 212b of the battery cell 20 does not melt when heated, setting the first groove 104 in the blank area 101b can significantly reduce the material used in the end cap body 212a and reduce the manufacturing cost of the end cap assembly 212.

[0184] According to some embodiments of this application, such as Figure 7 As shown, there are multiple first grooves 104, which are spaced apart around the coating area 101a. Thus, after the insulating layer 212b melts, the molten material on the coating area 101a can flow evenly to the inner circumferential surface of the housing 211, improving the sealing uniformity between the end cap body 212a and the inner circumferential surface of the housing 211.

[0185] When the battery cell 20 is heated and the insulating layer 212b does not melt, by setting multiple first grooves 104 on the blank area 101b, the material used in the end cap body 212a can be further reduced, thereby reducing the manufacturing cost of the end cap assembly 212.

[0186] In some embodiments of this application, such as Figure 8 and Figure 11 As shown, a second groove 105 is provided at the edge of the coating area 101a, and the end of the first groove 104 away from the outer peripheral surface 103 is connected to the second groove 105. The insulating layer 212b extends into the second groove 105, and the thickness of the insulating layer 212b in the second groove 105 is greater than that of the insulating layer 212b in other areas of the coating area 101a. Therefore, after the battery cell 20 is heated, the amount of material after the insulating layer 212b in the second groove 105 melts can support its flow to the inner peripheral surface of the housing 211, preventing the electrolyte from directly contacting the welding area between the end cap body 212a and the housing 211, reducing the probability of the welding area being corroded by the electrolyte, and thus reducing the probability of leakage due to welding area failure, ensuring good sealing performance between the end cap body 212a and the housing 211.

[0187] When the battery cell 20 is heated and the insulating layer 212b does not melt, the material used in the end cap body 212a can be further reduced by setting the second groove 105, thereby reducing the manufacturing cost of the end cap assembly 212.

[0188] In some embodiments of this application, such as Figure 8 and Figure 11 As shown, the bottom surface of the first groove 104 connects the bottom surface of the second groove 105 and the outer peripheral surface 103. Therefore, the portion of the insulating layer 212b located within the second groove 105 can easily flow through the bottom surface of the first groove 104 and reach the outer peripheral surface 103 or the inner peripheral surface of the housing 211 after the battery cell 20 is heated and melted, and can even reach the gap between the end cap body 212a and the housing 211.

[0189] Molten insulating material can flow from the first side 101 to the inner circumferential surface of the housing 211, and even flow into the gap between the end cap body 212a and the inner circumferential surface of the housing 211.

[0190] According to some embodiments of this application, such as Figure 7 As shown, the second groove 105 is an annular groove provided along the edge of the coating area 101a. Thus, the portion of the insulating layer 212b within the second groove 105 can have sufficient material after melting, and can be coated circumferentially onto the inner surface of the housing 211, thereby further improving the sealing performance between the end cap body 212a and the housing 211.

[0191] In some embodiments of this application, such as Figure 11 As shown, the angle between the guide slope 108 and the coating area 101a is α, which satisfies: 100°≤α≤160°. For example, α can be 100°, 115°, 120°, 125°, 130°, 135°, 140°, 145°, 150°, 155° or 160°.

[0192] The values ​​of α mentioned above are just some specific examples of embodiments of this application. As long as the included angle between the guide slope 108 and the coating area 101a meets the above range, it is within the protection scope of this application.

[0193] Since the angle between the guide slope 108 and the coating area 101a meets the above-mentioned range, on the one hand, the insulating layer 212b of the coating area 101a can flow more easily to the inner circumferential surface of the shell 211 after melting, and on the other hand, the tilt angle of the guide slope 108 is not too large, which would result in poor structural strength of the outer periphery of the end cap body 212a.

[0194] If the insulating layer 212b does not melt after the battery cell 20 is heated, since the angle between the guide slope 108 and the coating area 101a meets the above range, on the one hand, the weight of the end cap body 212a and the manufacturing cost of the end cap body 212a can be reduced, and on the other hand, the structural strength of the outer periphery of the end cap body 212a will not be poor.

[0195] In some embodiments according to this application, the melting point of the insulating layer 212b is greater than or equal to 85° and less than or equal to 120°. For example, the melting point of the insulating layer 212b can be 85°, 90°, 95°, 100°, 105°, 110°, 115° or 120°.

[0196] It should be noted that the melting point of the above-mentioned insulating layer 212b is only some specific embodiments of this application. As long as the melting point of the insulating layer 212b meets the above range, it is within the protection scope of this application.

[0197] Since the melting point of the insulating layer 212b meets the above-mentioned range, after the end cap body 212b is connected to the housing 211, on the one hand, the insulating layer 212b can melt when the battery cell 20 is heated (baking), so that the molten insulating material can flow through the blank area 101b and coat the blank area 101b, and then reach the inner circumferential surface of the housing 211, as well as the fixed connection area between the housing 211 and the end cap body 212a, to perform secondary sealing on the housing 211 and the end cap body 212a of the battery cell 20. On the other hand, the insulating layer 212b will not melt during normal use due to its low melting point, thus improving the stability of the insulating layer 212b.

[0198] In some embodiments of this application, the melting point of the insulating layer 212b is greater than or equal to 90° and less than or equal to 110°. For example, the melting point of the insulating layer 212b can be 90°, 96°, 102°, 108° or 110°.

[0199] It should be noted that the melting point of the above-mentioned insulating layer 212b is only some specific embodiments of this application. As long as the melting point of the insulating layer 212b meets the above range, it is within the protection scope of this application.

[0200] Since the melting point of the insulating layer 212b meets the above-mentioned range, after the end cap body 212b is connected to the housing 211, on the one hand, the insulating layer 212b can melt more easily when the battery cell 20 is heated (baking), so that the molten insulating material can more easily flow through the blank area 101b and coat the blank area 101b, and then reach the inner circumferential surface of the housing 211, as well as the fixed connection area between the housing 211 and the end cap body 212a, to perform secondary sealing of the housing 211 and the end cap body 212a of the battery cell 20. On the other hand, the insulating layer 212b will not melt during normal use due to the low melting point, which further improves the stability of the insulating layer 212b.

[0201] In some embodiments of this application, the insulating layer 212b may include one of paraffin wax, rosin, PE wax, polyolefin, stearic acid, and white oil. Thus, the insulating layer 212b can melt after the battery cell 20 is heated, and the molten insulating material can flow to the inner circumferential surface of the housing 211, providing a secondary seal between the end cap body 212a and the housing 211.

[0202] The following is a brief description of the battery cell 20 in an embodiment of this application.

[0203] According to an embodiment of this application, the battery cell 20 includes the end cap assembly 212 described above. It should be noted that the insulating layer 212b in the battery cell 20 does not melt after the battery cell 20 is heated, so the blank area 101b on the first side 101 of the end cap body 212a still exists.

[0204] Since the battery cell 20 according to the embodiment of this application is provided with the end cap assembly 212 described above, after the end cap assembly 212 is connected to the housing 211, the insulating layer 212b can effectively reduce the risk of the end cap body 212a being corroded by the electrolyte. At the same time, due to the presence of the blank area 101b, the connection effect between the end cap body 212a and the housing 211 will not be affected.

[0205] The battery 100 of this application embodiment is briefly described below.

[0206] According to the embodiments of this application, the battery 100 includes the battery cell 20 described above. It should be noted that the insulating layer 212b in the battery cell 20 does not melt after the battery cell 20 is heated, so the blank area 101b on the first side 101 of the end cap body 212a still exists.

[0207] Since the battery 100 according to the embodiment of this application is provided with the above-mentioned battery cell 20, the overall reliability of the battery 100 is better, and the risk of the end cap body 212a being corroded by the electrolyte is effectively reduced.

[0208] The electrical equipment of the present application embodiment is briefly described below.

[0209] The electrical device according to the embodiments of this application includes the battery cell 20 of the above embodiments or the battery of the above embodiments. In the battery cell 20 or the end cap assembly 212 of the battery, the insulating layer 212b does not melt after the battery cell 20 is heated, so the blank area 101b on the first side 101 of the end cap body 212a still exists.

[0210] Since the electrical device according to the embodiments of this application is equipped with the above-mentioned battery cell 20 or battery, the power supply stability of the electrical device is improved.

[0211] like Figure 12 As shown, the manufacturing method of the battery cell 20 according to the embodiments of this application will be described in detail below.

[0212] It should be noted that the insulating layer 212b in the end cap assembly 212 can melt after the battery cell 20 is heated.

[0213] In this step, the end cap assembly 212 includes an end cap body 212a and an insulating layer 212b. The end cap body 212a has a first side surface 101 and a second side surface 102 opposite to each other along its thickness direction, and an outer peripheral surface 103 connecting the first side surface 101 and the second side surface 102. The insulating layer 212b is disposed on the first side surface 101. The first side surface 101 includes a coating area 101a on which the insulating layer 212b is disposed and a blank area 101b on which the insulating layer 212b is not disposed. The blank area 101b is located between the coating area 101a and the outer peripheral surface 103.

[0214] At this time, the blank area 101b of the end cap body 212a still exists.

[0215] The housing 211 has an opening and an inner peripheral surface surrounding the opening. The housing 211 has a space inside, and the inner peripheral surface can enclose the opening.

[0216] Of course, the electrode assembly can be accessed into the housing 211 through the opening. Electrolyte can also be injected into the housing 211 before or after this step.

[0217] S1: The end cap assembly 212 is placed over the opening, such that the insulating layer 212b faces the inside of the housing 211. Thus, after the end cap assembly 212 is connected to the housing 211, the insulating layer 212b is encapsulated inside the housing 211, effectively reducing the probability of the molten insulating layer 212b overflowing to the outside of the housing 211.

[0218] S2: Connect the end cap body 212a and the housing 211 to form an assembly.

[0219] The end cap body 212a and the housing 211 can be fixed together by welding. The weld between the end cap body 212a and the housing 211 can be located on the outer part between the end cap body 212a and the housing 211.

[0220] S3: Heat the assembly to melt the insulating layer 212b and diffuse it into the blank area.

[0221] In order to obtain a qualified battery cell 20, the assembly needs to be heated. At this time, the insulating layer 212b is heated and melted, and then the molten insulating material can diffuse into the blank area 101b.

[0222] Therefore, the insulating layer 212b can completely cover the side of the end cap body 212a facing the inside of the housing 211, reducing the probability of contact between the electrolyte and the end cap body 212a, and effectively reducing the risk of the end cap body 212a being corroded by the electrolyte.

[0223] In some embodiments of this application, the molten insulating material may also diffuse to the inner circumferential surface of the housing 211.

[0224] Therefore, the end cap body 212a and the housing 211 can be sealed once through their fixed connection area, and the end cap body 212a and the housing 211 can be sealed twice through the insulating layer 212b.

[0225] S4: Cool the assembly to allow the insulation layer 212b to cure.

[0226] As the temperature decreases, the molten insulating material hardens and solidifies, allowing the portion of the insulating layer 212b flowing into the blank area 101b to completely cover the side of the end cap body 212a facing the inside of the housing 211, thus reducing the risk of the end cap body 212b being corroded by the electrolyte.

[0227] The portion of the insulating layer 212b that flows to the inner circumferential surface of the housing 211 will seal the gap between the end cap body 212a and the inner circumferential surface of the housing 211, thus achieving a secondary seal.

[0228] According to the manufacturing method of the battery cell 20 in this application embodiment, when the end cap body 212a is connected to the housing 211, the presence of the blank area 101b ensures that the insulating layer 212b does not obstruct the connection between the end cap body 212a and the housing 211, thus guaranteeing a smooth connection between the end cap body 212a and the housing 211 without affecting the connection strength and effect. Simultaneously, the molten insulating layer 212b can diffuse into the blank area 101b, thereby completely covering the side of the end cap body 212a facing the inside of the housing 211, reducing the probability of contact between the electrolyte and the end cap body 212b, and effectively reducing the risk of corrosion of the end cap body 212b by the electrolyte.

[0229] After the end cap assembly 212 and the housing 211 are assembled together to form an assembly, the assembly is heated. At this time, the insulating layer 212b melts, and the molten insulating material can also diffuse to the inner circumferential surface of the housing 211. Thus, not only can the end cap body 212a and the housing 211 be sealed once through the fixed connection area, but the solidified insulating material can also extend to the inner circumferential surface of the housing 211, thereby providing a secondary seal between the end cap body 212a and the housing 211. This further improves the sealing performance of the battery cell 20, further reduces the risk of electrolyte leakage in the battery cell 20, and improves the reliability of the battery cell.

[0230] In some embodiments of this application, the end cap assembly 212 faces downwards when the assembly is heated. As a result, the molten insulating material on the coating area 101a can flow towards the blank area 101b and even the inner circumferential surface of the housing 211 under the influence of gravity. This allows the insulating layer 212b to diffuse to the blank area 101b and the inner circumferential surface of the housing 211 after cooling, effectively reducing the risk of the end cap body being corroded by the electrolyte and achieving a secondary seal between the end cap body 212a and the housing 211.

[0231] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An end cap assembly for a battery cell, characterized in that, include: An end cap body having a first side surface and a second side surface opposite to each other along its thickness direction, and an outer peripheral surface connecting the first side surface and the second side surface; An insulating layer is disposed on the first side surface; The first side includes a coated area with the insulating layer and a blank area without the insulating layer, the blank area being located between the coated area and the outer peripheral surface.

2. The end cap assembly according to claim 1, characterized in that, The insulating layer includes a main body and a thickened portion, wherein the thickened portion is closer to the blank area than the main body. Wherein, along the thickness direction of the end cap body, the thickness of the thickened portion is greater than the thickness of the body portion.

3. The end cap assembly according to claim 2, characterized in that, The thickened portion has a first side adjacent to the main body and a second side adjacent to the blank area, and the thickness of the thickened portion gradually increases from the first side to the second side.

4. The end cap assembly according to claim 2, characterized in that, The thickness of the thickened part is t, and satisfies: 0mm < t ≤ 5mm.

5. The end cap assembly according to claim 2, characterized in that, The thickened portion is arranged around the main body portion.

6. The end cap assembly according to any one of claims 1-5, characterized in that, The blank area is a ring-shaped region surrounding the coated area.

7. The end cap assembly according to claim 6, characterized in that, The area of ​​the first side is S, and the area of ​​the side of the insulating layer facing the inside of the battery cell is S1, satisfying: 13% ≤ S1 / S ≤ 99%.

8. The end cap assembly according to claim 6, characterized in that, The width of the blank area is D, which satisfies 0.5mm≤D≤5mm.

9. The end cap assembly according to claim 1, characterized in that, The blank area includes a guide slope, and the guide slope is not on the same plane as the coating area.

10. The end cap assembly according to claim 9, characterized in that, The angle between the guide ramp and the outer peripheral surface is an obtuse angle.

11. The end cap assembly according to claim 9, characterized in that, The guide ramp surrounds the coating area.

12. The end cap assembly according to claim 9, characterized in that, The blank area is provided with a first groove, one end of which extends to the outer peripheral surface, and at least a portion of the bottom surface of the first groove is constructed as the guide slope.

13. The end cap assembly according to claim 12, characterized in that, There are multiple first grooves, which are spaced apart around the coating area.

14. The end cap assembly according to claim 13, characterized in that, The edge of the coating area is provided with a second groove, and the end of the first groove away from the outer peripheral surface is connected to the second groove.

15. The end cap assembly according to claim 14, characterized in that, The bottom surface of the first groove connects the bottom surface of the second groove and the outer peripheral surface.

16. The end cap assembly according to claim 14, characterized in that, The second groove is an annular groove formed along the edge of the coating area.

17. The end cap assembly according to any one of claims 9-16, characterized in that, The angle between the guide slope and the coating area is α, which satisfies: 100°≤α≤160°.

18. The end cap assembly according to claim 1, characterized in that, The melting point of the insulating layer is greater than or equal to 85°C and less than or equal to 120°C.

19. The end cap assembly according to claim 18, characterized in that, The melting point of the insulating layer is greater than or equal to 90°C and less than or equal to 110°C.

20. The end cap assembly according to claim 1, characterized in that, The insulating layer comprises one or more of paraffin wax, rosin, PE wax, polyolefin, stearic acid, and white oil.

21. A single battery cell, characterized in that, Includes the end cap assembly according to any one of claims 1-20.

22. A method of using an end cap assembly as described in any one of claims 1-20, characterized in that, include: The end cap assembly is placed over the opening of the housing, such that the insulating layer faces the interior of the housing; The end cap body and the housing are connected to form an assembly; The assembly is heated to melt the insulating layer and allow it to diffuse into the blank area; The assembly is cooled to cure the insulating layer.

23. The method of using the end cap assembly according to claim 22, characterized in that, When the assembly is heated, the end cap assembly is oriented downwards.

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