End cap assembly, battery cell, battery, and electric device

Abstract

Embodiments of the present application provide an end cover assembly, a battery monomer, a battery and an electric device. The end cover assembly comprises an end cover, a pressure relief mechanism and a protective sheet. The end cover comprises a main body portion and a protruding portion, the protruding portion protrudes from the main body portion along the thickness direction of the end cover, the end cover is provided with a through hole, the through hole penetrates the main body portion and the protruding portion. The pressure relief mechanism is arranged on the side of the main body portion away from the protruding portion and covers the through hole, the pressure relief mechanism is configured to actuate to release the internal pressure through the through hole when the internal pressure of the battery monomer reaches a threshold value. The protective sheet is attached to the surface of the protruding portion away from the main body portion and covers the through hole. The protruding portion comprises a first protruding portion and a second protruding portion, the first protruding portion is arranged around the through hole, the second protruding portion is arranged outside the first protruding portion, a first recess portion is formed between the first protruding portion and the second protruding portion, and the first recess portion is communicated with the through hole and the external space of the end cover. The present application can reduce the risk of corrosion of the pressure relief mechanism and improve safety.

Description

Technical Field

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

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools. Battery cells can include nickel-cadmium battery cells, nickel-metal hydride battery cells, lithium-ion battery cells, and rechargeable alkaline zinc-manganese battery cells, among others.

[0003] In the development of battery technology, improving the safety of individual battery cells is a key research direction. Summary of the Invention

[0004] This application provides an end cap assembly and its manufacturing method and system, a battery cell, a battery, and an electrical device, which can improve the safety of the battery cell.

[0005] In a first aspect, embodiments of this application provide an end cap assembly for a battery cell, including an end cap, a pressure relief mechanism, and a protective sheet. The end cap includes a main body and a protrusion, the protrusion extending beyond the main body along the thickness direction of the end cap. The end cap has a through hole that passes through the main body and the protrusion. The pressure relief mechanism is disposed on the side of the main body opposite to the protrusion and covers the through hole. The pressure relief mechanism is configured to be actuated when the internal pressure of the battery cell reaches a threshold value to release the internal pressure through the through hole. The protective sheet is attached to the surface of the protrusion opposite to the main body and covers the through hole. The protrusion includes a first protrusion and a second protrusion, the first protrusion surrounding the through hole, and the second protrusion surrounding the outside of the first protrusion. A first recess is formed between the first and second protrusions, the first recess communicating with the through hole and the external space of the end cap.

[0006] In this application, both the first and second protrusions extend beyond the main body, working together to provide double-layer protection and reduce the risk of external impurities entering the through-hole. The first recess connects the through-hole and the external space of the end cap, ensuring the accuracy of the battery cell's airtightness testing. When external impurities accumulate or pass through the second protrusion due to battery cell vibration, the first recess can accommodate these impurities, thus providing a storage function and increasing the difficulty for external impurities to enter the through-hole, reducing the risk of corrosion to the pressure relief mechanism and improving safety.

[0007] In some embodiments, a first groove is provided on the surface of the first protrusion facing away from the main body, the first groove being used to connect the through hole and the first recess. A second groove is provided on the surface of the second protrusion facing away from the main body, the second groove being used to connect the first recess and the external space of the end cap.

[0008] In the above embodiment, the first groove, the first recess, and the second groove form a channel connecting the through hole to the external space, facilitating the airtightness testing of the battery cell. The first groove and the second groove are recessed from the top of the first protrusion and the top of the second protrusion, respectively. This ensures the spacing between the first groove and the main body in the thickness direction, as well as the spacing between the second groove and the main body in the thickness direction, reducing the risk of external impurities passing through the second groove and the first groove.

[0009] In some embodiments, in the thickness direction, the depth of the first groove and the depth of the second groove are both less than the depth of the first recess.

[0010] In the above embodiment, the first recess has a greater depth, which can provide more space for external impurities; the depths of the first groove and the second groove are both smaller, which increases the difficulty for external impurities to pass through the first and second protrusions and reduces the risk of external impurities entering the through hole.

[0011] In some embodiments, the first groove and the second groove are offset in the circumferential direction of the through hole.

[0012] The above-described embodiments can increase the circumferential distance between the first groove and the second groove, lengthen the path for external impurities to move from the second groove to the first groove, and increase the difficulty for external impurities to enter the through hole.

[0013] In some embodiments, the first groove and the second groove are misaligned by an angle of 90°-180° in the circumferential direction of the through hole.

[0014] The above-described embodiments can ensure the circumferential spacing between the first groove and the second groove, increasing the difficulty for external impurities to enter the through hole.

[0015] In some embodiments, the main body is provided with an injection hole for injecting electrolyte into the battery cell. A first groove is located between the through hole and the injection hole, and a second groove is located on the side of the through hole opposite to the injection hole.

[0016] In the above embodiment, the second groove is disposed on the side of the through hole away from the injection hole. In this way, the electrolyte splashed out from the injection hole will be blocked by the second protrusion and the protective sheet, so that the electrolyte is less likely to splash into the second groove, reducing the risk of electrolyte entering the through hole and improving the safety of the battery cell.

[0017] In some embodiments, the protective sheet includes a base layer and an adhesive layer. The base layer covers the through-hole, and the adhesive layer is disposed on the surface of the base layer facing the protrusion and bonded to the first and second protrusions. No adhesive layer is disposed in the region of the base layer opposite the first groove in the thickness direction, and no adhesive layer is disposed in the region of the base layer opposite the second groove in the thickness direction.

[0018] The above-described embodiment sets the first groove and the adhesive layer apart, and sets the second groove and the adhesive layer apart, which can reduce the risk of the adhesive layer clogging the first groove and the second groove.

[0019] In some embodiments, the first recess includes a first portion and a second portion disposed circumferentially along the through hole, the first portion communicating with a first groove and the second portion communicating with a second groove. In the thickness direction, the depth of the first portion is less than the depth of the second portion.

[0020] In the above embodiment, external impurities will first enter the second part through the second groove. Since the depth of the second part is greater than the depth of the first part, the external impurities will first accumulate in the second part and will not easily enter the first part directly. This increases the difficulty for external impurities to enter the through hole through the first groove, reduces the risk of corrosion of the pressure relief mechanism, and improves safety.

[0021] In some embodiments, the first recess includes a third portion that connects the first portion and the second portion. In the thickness direction, the depth of the third portion is greater than the depth of the first portion and less than the depth of the second portion.

[0022] In the above embodiment, the bottom surface of the first recess is formed with multiple steps. In this way, the difficulty for impurities to move towards the first groove in the first recess gradually increases, thereby reducing the difficulty for impurities to enter the through hole through the first groove, reducing the risk of corrosion of the pressure relief mechanism, and improving safety.

[0023] In some embodiments, in the circumferential direction of the through hole, at least a portion of the depth of the first portion gradually decreases in the direction approaching the first groove.

[0024] In the above embodiment, even if external impurities enter the first part, the difficulty for them to move towards the first groove in the first part gradually increases, thereby reducing the difficulty for impurities to enter the through hole through the first groove, reducing the risk of corrosion of the pressure relief mechanism, and improving safety.

[0025] In some embodiments, in the circumferential direction of the through hole, at least a portion of the depth of the first recess gradually decreases in the direction approaching the first groove.

[0026] In the above embodiment, even if external impurities enter the first recess, the difficulty for them to move towards the first groove in the first recess gradually increases, thereby reducing the difficulty for impurities to enter the through hole through the first recess, reducing the risk of corrosion of the pressure relief mechanism, and improving safety.

[0027] In some embodiments, the surface of the first protrusion facing away from the main body is flush with the surface of the second protrusion facing away from the main body, so as to facilitate the attachment of the protective sheet to the first protrusion and the attachment of the protective sheet to the second protrusion.

[0028] In some embodiments, at least a portion of the first recess is recessed into the main body portion.

[0029] The above-described embodiments can increase the depth of the first recess to provide more space for external impurities, increase the difficulty for external impurities to enter the through hole, reduce the risk of corrosion of the pressure relief mechanism, and improve safety.

[0030] In some implementations, a protective sheet covers the first recess to reduce the risk of external impurities directly entering the first recess.

[0031] Secondly, embodiments of this application provide a battery cell, including a housing, an electrode assembly, and an end cap assembly according to any embodiment of the first aspect. The housing has an opening. The electrode assembly is housed within the housing. The end cap of the end cap assembly is used to close the opening, and a protrusion is located on the side of the main body opposite to the electrode assembly.

[0032] Thirdly, embodiments of this application provide a battery comprising a plurality of battery cells as described in the second aspect.

[0033] Fourthly, embodiments of this application provide an electrical device, including a battery cell as described in the second aspect, the battery cell being used to provide electrical energy.

[0034] Fifthly, embodiments of this application provide a method for manufacturing an end cap assembly, comprising: An end cap is provided, the end cap including a main body and a protrusion, the protrusion protruding from the main body along the thickness direction of the end cap, the end cap having a through hole that passes through the main body and the protrusion, the protrusion including a first protrusion and a second protrusion, the first protrusion surrounding the through hole, the second protrusion surrounding the outside of the first protrusion, a first recess being formed between the first protrusion and the second protrusion, the first recess communicating with the through hole and the external space of the end cap; A pressure relief mechanism is provided and is located on the side of the main body away from the protrusion, and the pressure relief mechanism covers the through hole; A protective sheet is provided and attached to the surface of the protrusion opposite to the main body, and the protective sheet covers the through hole; The pressure relief mechanism is configured to be actuated when the internal pressure of a battery cell reaches a threshold to release the internal pressure through a through-hole.

[0035] Sixthly, embodiments of this application provide a manufacturing system for an end cap assembly, including a first providing device, a second providing device, and a third providing device. The first providing device provides an end cap, which includes a main body and a protrusion. The protrusion protrudes from the main body along the thickness direction of the end cap. The end cap has a through hole that passes through the main body and the protrusion. The protrusion includes a first protrusion and a second protrusion. The first protrusion surrounds the through hole, and the second protrusion surrounds the outside of the first protrusion. A first recess is formed between the first and second protrusions, and the first recess communicates with the through hole and the external space of the end cap. The second providing device provides a pressure relief mechanism, which is disposed on the side of the main body opposite to the protrusion and covers the through hole. The third providing device provides a protective sheet, which is attached to the surface of the protrusion opposite to the main body and covers the through hole. The pressure relief mechanism is configured to be actuated when the internal pressure of a battery cell reaches a threshold value to release the internal pressure through the through hole. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0037] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments; Figure 2 Explosion diagrams of batteries provided for some embodiments of this application; Figure 3 for Figure 2 An exploded view of the battery module shown. Figure 4 This is an exploded schematic diagram of a battery cell provided in some embodiments of this application; Figure 5 This is a schematic diagram of the structure of the end cap assembly provided in some embodiments of this application; Figure 6 A cross-sectional schematic diagram of an end cap assembly provided in some embodiments of this application; Figure 7 for Figure 6 The diagram shows an enlarged view of the end cap assembly at point A in the circle. Figure 8 for Figure 7 Enlarged view of point B in the circle; Figure 9 for Figure 7 Enlarged view of point C in the circle; Figure 10This is a schematic diagram of the structure of the protective sheet provided in some embodiments of this application; Figure 11 This is a top view schematic diagram of the end cap of the end cap assembly provided in some embodiments of this application; Figure 12 for Figure 11 Enlarged view of point D in the circle; Figure 13 for Figure 12 A schematic sectional view along the section line EE; Figure 14 for Figure 12 Another schematic sectional view along the section line EE; Figure 15 This is a schematic flowchart illustrating a method for manufacturing an end cap assembly according to some embodiments of this application; Figure 16 A schematic block diagram of a manufacturing system for an end cap assembly provided in some embodiments of this application.

[0038] The accompanying drawings are not drawn to scale. Detailed Implementation

[0039] 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 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.

[0040] 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.

[0041] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0042] 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.

[0043] 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.

[0044] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0045] In this application, "multiple" means two or more (including two).

[0046] In this application, the battery cell may include a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, etc., and the embodiments of this application are not limited thereto. The battery cell may be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this application are not limited thereto.

[0047] 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. For example, the battery mentioned in this application may include a battery module or a battery pack. A battery generally includes a housing for encapsulating one or more battery cells. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0048] A single battery cell includes electrode components and an electrolyte. The electrode components include a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of metal ions between the positive and negative electrodes. The positive electrode includes a positive current collector and a positive active material layer, which is coated on the surface of the positive current collector. The positive current collector includes a positive electrode coating area and a positive electrode tab connected to the coating area. The coating area is coated with the positive active material layer, while the tab is not. Taking a lithium-ion battery cell as an example, the positive current collector can be made of aluminum, and the positive active material layer includes the positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, the negative electrode active material layer being coated on the surface of the negative electrode current collector. The negative electrode current collector includes a negative electrode coating area and a negative electrode tab connected to the negative electrode coating area. The negative electrode coating area is coated with the negative electrode active material layer, while the negative electrode tab is not coated with the negative electrode active material layer. The material of the negative electrode current collector can be copper, and the negative electrode active material layer includes negative electrode active material, which can be carbon or silicon, etc. The material of the separator can be PP (polypropylene) or PE (polyethylene), etc.

[0049] The battery cell also includes a housing, the interior of which forms a receiving cavity for accommodating the electrode assembly. The housing can protect the electrode assembly from the outside to prevent external foreign objects from affecting the charging or discharging of the electrode assembly. Exemplarily, the housing includes a casing and an end cap, the casing having an opening and the end cap closing onto the opening of the casing.

[0050] The development of battery technology must take into account multiple design factors, such as energy density, cycle life, discharge capacity, charge / discharge rate and other performance parameters. In addition, battery safety also needs to be considered.

[0051] The pressure relief mechanism on a battery cell has a significant impact on its safety. For example, in the event of a short circuit or overcharging, thermal runaway may occur inside the battery cell, causing a sudden increase in pressure. In such cases, the pressure relief mechanism can be activated to release the internal pressure, preventing the battery cell from exploding or catching fire.

[0052] A pressure relief mechanism is a component or part that is activated to release internal pressure when the internal pressure of a battery cell reaches a predetermined threshold. This threshold design varies depending on design requirements. It may depend on the materials of one or more of the components in the battery cell: the positive electrode, the negative electrode, the electrolyte, and the separator.

[0053] The pressure relief mechanism can take the form of an explosion-proof valve, a gas valve, a pressure relief valve, or a safety valve, and can specifically adopt a pressure-sensitive element or structure. That is, when the internal pressure of a battery cell reaches a predetermined threshold, the pressure relief mechanism performs an action or a weak area provided in the pressure relief mechanism ruptures, thereby forming an opening or channel for internal pressure to be released.

[0054] The term "actuation" as used in this application refers to the activation or actuation of the pressure relief mechanism to a certain state, thereby releasing the internal pressure of the battery cell. The actions of the pressure relief mechanism may include, but are not limited to, at least a portion of the mechanism rupturing, breaking, tearing, or opening. When the pressure relief mechanism is actuated, the high-temperature, high-pressure substances inside the battery cell are discharged as waste from the actuated portion. This method allows for pressure relief of the battery cell under controlled pressure, thereby preventing potentially more serious accidents.

[0055] The emissions from battery cells mentioned in this application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0056] In related technologies, the end cap is provided with a through hole for venting, and a pressure relief mechanism is installed inside the end cap and covers the through hole. When the pressure relief mechanism is activated, high-temperature and high-pressure substances are discharged to the outside of the battery cell through the through hole.

[0057] To reduce the amount of external impurities entering the through-hole and lower the risk of corrosion of the pressure relief mechanism by these impurities, the inventors attached a protective sheet to the outside of the end cap. This protective sheet covers the through-hole from the outside to reduce the amount of impurities entering. However, the protective sheet is a thin film structure with low strength; when the pressure relief mechanism is activated, it is easily ruptured by high-temperature, high-pressure substances, thus failing to prevent the discharge of these substances.

[0058] During the production of battery cells, the pressure relief mechanism may break, leading to its failure. When performing airtightness testing on battery cells, the protective sheet covers the through-hole from the outside, making it impossible to accurately detect whether the pressure relief mechanism has failed. The inventors attempted to create a venting groove on the end cap to connect the through-hole to the external space of the battery cell. This allows for accurate detection of pressure relief mechanism failure during airtightness testing.

[0059] However, the inventors discovered that during the production and use of battery cells, external impurities, such as metal particles and electrolytes, may enter the through holes through the venting grooves, thereby causing the pressure relief mechanism to be corroded, leading to its failure and creating safety hazards.

[0060] In view of this, embodiments of this application provide an end cap assembly for a battery cell, which includes an end cap, a pressure relief mechanism, and a protective sheet. The end cap includes a main body and a protrusion, the protrusion extending beyond the main body along the thickness direction of the end cap. The end cap has a through hole that passes through the main body and the protrusion. The pressure relief mechanism is disposed on the side of the main body opposite to the protrusion and covers the through hole. The pressure relief mechanism is configured to be actuated when the internal pressure of the battery cell reaches a threshold to release the internal pressure through the through hole. The protective sheet is attached to the surface of the protrusion opposite to the main body and covers the through hole. The protrusion includes a first protrusion and a second protrusion, the first protrusion surrounding the through hole, and the second protrusion surrounding the outside of the first protrusion. A first recess is formed between the first and second protrusions, the first recess communicating with the through hole and the external space of the end cap. In this application, the first convex portion and the second convex portion can serve as a double layer of protection to reduce the risk of external impurities entering the through hole, while the first concave portion can accommodate external impurities that pass through the second convex portion, which can serve as a storage function and increase the difficulty for external impurities to enter the through hole, thereby reducing the risk of corrosion of the pressure relief mechanism and improving safety.

[0061] The end cap assembly described in the embodiments of this application is applicable to battery cells, batteries, and electrical devices that use batteries.

[0062] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0063] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0064] Figure 1 The diagram shows the structural features of a vehicle provided in some embodiments of this application.

[0065] like Figure 1 As shown, a battery 2 is installed inside the vehicle 1. The battery 2 can be located at the bottom, front, or rear of the vehicle 1. The battery 2 can be used to power the vehicle 1; for example, the battery 2 can serve as the operating power source for the vehicle 1.

[0066] Vehicle 1 may also include controller 3 and motor 4. Controller 3 is used to control battery 2 to supply power to motor 4, for example, for the power needs of vehicle 1 during start-up, navigation and driving.

[0067] In some embodiments of this application, the battery 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0068] Figure 2 This is an exploded schematic diagram of a battery provided for some embodiments of this application.

[0069] like Figure 2 As shown, battery 2 includes a housing 5 and battery cells (not shown), with the battery cells housed within the housing 5.

[0070] The housing 5 is used to house individual battery cells, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the individual battery cells. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as cylinders, cuboids, etc.

[0071] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0072] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0073] In battery 2, there can be one or more individual battery cells. If there are multiple individual battery cells, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple individual battery cells are connected in both series and parallel configurations. Multiple individual battery cells can be directly connected in series, parallel, or in a mixed configuration and then housed within housing 5. Alternatively, multiple individual battery cells can first be connected in series, parallel, or in a mixed configuration to form battery module 6, and then multiple battery modules 6 can be connected in series, parallel, or in a mixed configuration to form a whole and housed within housing 5.

[0074] Figure 3 for Figure 2 The diagram shows an exploded view of the battery module.

[0075] In some embodiments, such as Figure 3 As shown, there are multiple battery cells 7, which are first connected in series, parallel, or a combination of both to form a battery module 6. These battery modules 6 are then connected in series, parallel, or a combination of both to form a whole, which is housed within the casing.

[0076] Multiple battery cells 7 in battery module 6 can be electrically connected through a busbar component to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6.

[0077] Figure 4 This is an exploded schematic diagram of a battery cell provided in some embodiments of this application.

[0078] like Figure 4 As shown, the battery cell 7 includes an electrode assembly 10, a housing 20, and an end cap assembly 30. The housing 20 has an opening, and the electrode assembly 10 is housed within the housing 20. The end cap assembly 30 includes an end cap 31 for closing the opening.

[0079] The electrode assembly 10 is the core component for enabling the charging and discharging function of the battery cell 7. It includes a positive electrode, a negative electrode, and a separator. The positive and negative electrodes have opposite polarities, and the separator is used to insulate and isolate the positive and negative electrodes. The electrode assembly 10 mainly relies on the movement of metal ions between the positive and negative electrodes to operate.

[0080] There can be one or more electrode assemblies 10. When there are multiple electrode assemblies 10, they can be stacked. For example, as shown... Figure 4 As shown, there are four electrode assemblies 10.

[0081] The housing 20 is a hollow structure, with an internal cavity for accommodating the electrode assembly 10 and the electrolyte. The housing 20 can be of various shapes, such as a cylinder or a cuboid. The shape of the housing 20 can be determined based on the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 is a cylindrical structure, a cylindrical housing can be used; if the electrode assembly 10 is a cuboid structure, a cuboid housing can be used.

[0082] The housing 20 may have an opening on one side, with an end cap 31 that covers the opening of the housing 20. Alternatively, the housing 20 may have an opening on both sides, with two end caps 31 that cover the two openings of the housing 20 respectively.

[0083] For example, the end cap 31 is attached to the housing 20 by welding, bonding, snap-fitting or other means.

[0084] The shape of the end cap 31 can be adapted to the shape of the housing 20 to fit the housing 20. Optionally, the end cap 31 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 31 is not easily deformed when subjected to compression and impact, so that the battery cell 7 can have higher structural strength and improve safety performance. The material of the end cap 31 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this.

[0085] In some embodiments, the end cap assembly 30 further includes two electrode terminals 32, which may be disposed on the end cap 31. The two electrode terminals 32 are a positive electrode terminal and a negative electrode terminal, respectively. The positive electrode terminal is used to electrically connect with the positive electrode plate of the electrode assembly 10, and the negative electrode terminal is used to electrically connect with the negative electrode plate, so as to lead the electrical energy generated by the electrode assembly 10 out of the housing 20.

[0086] In some embodiments, each electrode terminal 32 is provided with a corresponding connecting member 40, or a current collector, which is located between the end cap 31 and the electrode assembly 10, for electrically connecting the electrode terminal 32 and the corresponding electrode plate.

[0087] Figure 5 This is a schematic diagram of the structure of the end cap assembly provided in some embodiments of this application; Figure 6 A cross-sectional schematic diagram of an end cap assembly provided in some embodiments of this application; Figure 7 for Figure 6 The diagram shows an enlarged view of the end cap assembly at point A in the circle. Figure 8 for Figure 7 Enlarged view of point B in the circle; Figure 9 for Figure 7 Enlarged view of point C in the circle.

[0088] like Figures 5 to 9As shown, the end cap assembly 30 of this embodiment includes an end cap 31, a pressure relief mechanism 33, and a protective sheet 34. The end cap 31 includes a main body 311 and a protrusion 312. The protrusion 312 protrudes from the main body 311 along the thickness direction Z of the end cap 31. The end cap 31 has a through hole 313 that passes through the main body 311 and the protrusion 312. The pressure relief mechanism 33 is disposed on the side of the main body 311 opposite to the protrusion 312 and covers the through hole 313. The pressure relief mechanism 33 is configured to be actuated when the internal pressure of the battery cell 7 reaches a threshold value to release the internal pressure through the through hole 313. The protective sheet 34 is attached to the surface of the protrusion 312 opposite to the main body 311 and covers the through hole 313. The protrusion 312 includes a first protrusion 3121 and a second protrusion 3122. The first protrusion 3121 is disposed around the through hole 313, and the second protrusion 3122 is disposed around the outside of the first protrusion 3121. A first recess 314 is formed between the first protrusion 3121 and the second protrusion 3122. The first recess 314 communicates with the external space of the through hole 313 and the end cap 31.

[0089] The main body 311 has an inner surface and an outer surface disposed opposite to each other in the thickness direction Z. The inner surface of the main body 311 faces the electrode assembly 10, and the outer surface of the main body 311 faces away from the electrode assembly 10. Exemplarily, both the inner surface and the outer surface of the main body 311 are planar. A protrusion 312 protrudes from the outer surface of the main body 311.

[0090] The protrusion 312 is an annular structure surrounding the through hole 313, and the protrusion 312 forms part of the through hole 313.

[0091] The through hole 313 can be circular, square, racetrack-shaped, or other shapes. For example, the through hole 313 can be a constant diameter hole or a variable diameter hole, such as a stepped hole.

[0092] The pressure relief mechanism 33 is connected to the main body 311 and covers the through hole 313. In the battery cell 7, the pressure relief mechanism 33 can seal the through hole 313 to separate the space on both sides of the end cover 31, prevent the electrolyte from flowing out through the through hole 313, and improve the sealing performance of the battery cell.

[0093] The pressure relief mechanism 33 and the end cap 31 can be two separate components, which can be fixedly connected by welding, bonding or other connection methods. Alternatively, the pressure relief mechanism 33 and the end cap 31 can also be an integrally formed structure.

[0094] The pressure relief mechanism 33 can be any possible pressure relief structure, and the embodiments of this application are not limited to this. For example, the pressure relief mechanism 33 can be a pressure-sensitive pressure relief mechanism, which is configured to rupture when the internal gas pressure of the battery cell 7 equipped with the pressure relief mechanism 33 reaches a threshold.

[0095] In the description of this embodiment, attachment means sticking and connecting; when one component is attached to another component, the two components are connected at their contact surfaces. For example, the protective sheet 34 can be attached to the protrusion 312 by adhesive or other means.

[0096] The protective sheet 34 can cover the through hole 313 on the side of the protrusion 312 opposite to the main body 311 to block external impurities and reduce the risk of external impurities entering the through hole 313.

[0097] The first recess 314 is recessed relative to the surface of the first protrusion 3121 that is away from the main body 311, and is also recessed relative to the surface of the second protrusion 3122 that is away from the main body 311; in other words, both the first protrusion 3121 and the second protrusion 3122 protrude from the bottom surface of the first recess 314.

[0098] The first recess 314 is connected to the external space of the through hole 313 and the end cap 31. This embodiment does not limit the way the first recess 314 and the through hole 313 are connected, nor does it limit the way the first recess 314 and the external space of the end cap 31 are connected.

[0099] For example, a first connecting structure is formed on the first protrusion 3121, which connects the first recess 314 and the through hole 313. For example, the first connecting structure may be a groove, a hole or other structure.

[0100] A second connecting structure is formed on the second protrusion 3122, which connects the first recess 314 and the external space of the end cap 31. For example, the second connecting structure may be a groove, a hole or other structure.

[0101] The protective plate 34 can be connected only to the first protrusion 3121, or only to the second protrusion 3122, or both the first protrusion 3121 and the second protrusion 3122.

[0102] The surface of the first protrusion 3121 facing away from the main body 311 and the surface of the second protrusion 3122 facing away from the main body 311 may or may not be flush. For example, in the thickness direction Z, the surface of the first protrusion 3121 facing away from the main body 311 may extend beyond the surface of the second protrusion 3122 facing away from the main body 311.

[0103] In this embodiment, the depth of the first recess 314 is not limited. The first recess 314 can be located entirely within the protrusion 312 or recessed into the main body 311.

[0104] During the production process of a battery cell, external impurities (such as metal particles, electrolyte, etc.) may remain on the main body 311.

[0105] In this embodiment, both the first protrusion 3121 and the second protrusion 3122 protrude from the main body 311, and together they provide double-layer protection to reduce the risk of external impurities entering the through hole 313. The first recess 314 connects the through hole 313 and the external space of the end cap 31, thus ensuring the accuracy of the airtightness test of the battery cell. When external impurities accumulate or pass through the second protrusion 3122 due to vibration of the battery cell, the first recess 314 can accommodate the external impurities that have passed through the second protrusion 3122, thereby providing a storage function and increasing the difficulty for external impurities to enter the through hole 313, reducing the risk of corrosion of the pressure relief mechanism 33, and improving safety.

[0106] In some embodiments, the protective sheet 34 is simultaneously attached to the first protrusion 3121 and the second protrusion 3122 to increase the connection strength between the protective sheet 34 and the end cap 31.

[0107] In some embodiments, the surface of the first protrusion 3121 facing away from the main body 311 is flush with the surface of the second protrusion 3122 facing away from the main body 311. This embodiment facilitates the attachment of the protective sheet 34 to the first protrusion 3121 and the attachment of the protective sheet 34 to the second protrusion 3122.

[0108] In some embodiments, at least a portion of the first recess 314 is recessed into the main body 311. This embodiment can increase the depth of the first recess 314 to provide more space for external impurities, making it more difficult for external impurities to enter the through hole 313, reducing the risk of corrosion of the pressure relief mechanism 33, and improving safety.

[0109] In some embodiments, the protective sheet 34 covers the first recess 314 to reduce the risk of external impurities directly entering the first recess 314.

[0110] In some embodiments, a first groove 3121a is provided on the surface of the first protrusion 3121 facing away from the main body 311, and the first groove 3121a is used to connect the through hole 313 and the first recess 314. A second groove 3122a is provided on the surface of the second protrusion 3122 facing away from the main body 311, and the second groove 3122a is used to connect the first recess 314 and the external space of the end cap 31.

[0111] The first groove 3121a penetrates the first protrusion 3121. Exemplarily, the first groove 3121a extends from the inner side of the first protrusion 3121 to the outer side of the first protrusion 3121, forming an opening communicating with the through hole 313 on the inner side of the first protrusion 3121 and an opening communicating with the first recess 314 on the outer side of the first protrusion 3121. The first groove 3121a can extend in a straight line, in a wavy shape, or in other shapes. The cross-section of the first groove 3121a perpendicular to the extending direction can be triangular, trapezoidal, rectangular, semi-circular, or other shapes.

[0112] The second groove 3122a extends through the second protrusion 3122. Exemplarily, the second groove 3122a extends from the inner side of the second protrusion 3122 to the outer side of the second protrusion 3122, forming an opening on the inner side of the second protrusion 3122 that communicates with the first recess 314, and an opening on the outer side of the second protrusion 3122 that communicates with the external space. The second groove 3122a can extend in a straight line, in a wavy shape, or in other shapes. The cross-section of the second groove 3122a perpendicular to the extending direction can be triangular, trapezoidal, rectangular, semi-circular, or other shapes.

[0113] In this embodiment, the first groove 3121a, the first recess 314, and the second groove 3122a form a channel connecting the through hole 313 with the external space, facilitating the airtightness testing of the battery cell 7. The first groove 3121a and the second groove 3122a are recessed from the top of the first protrusion 3121 and the top of the second protrusion 3122, respectively. This ensures the spacing between the first groove 3121a and the main body 311 in the thickness direction Z, as well as the spacing between the second groove 3122a and the main body 311 in the thickness direction Z, reducing the risk of external impurities passing through the second groove 3122a and the first groove 3121a.

[0114] In some embodiments, in the thickness direction Z, the depth of the first groove 3121a and the depth of the second groove 3122a are both less than the depth of the first recess 314.

[0115] In this embodiment, the first recess 314 has a greater depth, which can provide more space for external impurities; the depths of the first groove 3121a and the second groove 3122a are both smaller, which increases the difficulty for external impurities to pass through the first protrusion 3121 and the second protrusion 3122, and reduces the risk of external impurities entering the through hole 313.

[0116] The depth of the first groove 3121a is less than the depth of the first recess 314. In this way, the bottom surface of the first groove 3121a will be higher than the bottom surface of the first recess 314, and impurities accumulated on the bottom surface of the first recess 314 will not easily flow into the first groove 3121a.

[0117] In some embodiments, the end cap 31 further includes a bend 315 and a connecting portion 316. The bend 315 surrounds the outside of the body portion 311 and extends in a direction facing the electrode assembly to form a second recess 317 on the side of the body portion 311 facing the electrode assembly. The connecting portion 316 surrounds the outside of the bend 315, and the second recess 317 is recessed relative to the surface of the connecting portion 316 facing the electrode assembly. The connecting portion 316 is used for connection with the housing.

[0118] This embodiment can increase the internal space of the battery cell and improve the capacity of the battery cell by providing the second recess 317.

[0119] Figure 10 This is a schematic diagram of the structure of the protective sheet provided in some embodiments of this application.

[0120] Please refer to the above as well. Figures 8 to 10 In some embodiments, the protective sheet 34 includes a base layer 341 and an adhesive layer 342. The base layer 341 covers the through hole 313, and the adhesive layer 342 is disposed on the surface of the base layer 341 facing the protrusion 312 and is bonded to the first protrusion 3121 and the second protrusion 3122. The region of the base layer 341 opposite to the first groove 3121a in the thickness direction Z is not provided with the adhesive layer 342, and the region of the base layer 341 opposite to the second groove 3122a in the thickness direction Z is also not provided with the adhesive layer 342.

[0121] The base layer 341 is used to block external impurities. Its material can be polyethylene terephthalate (PET), polypropylene (PP) or polycarbonate (PC), but is not limited to the above-mentioned types. It can be selected according to the needs.

[0122] The adhesive layer 342 is used to bond the base layer 341 to the first protrusion 3121 and the second protrusion 3122 to fix the base layer 341 to the end cap 31. The adhesive layer 342 may include at least one of polyurethane, polyacrylate and styrene-butadiene rubber, but is not limited to the above, and can be selected according to needs.

[0123] The adhesive layer 342 and the first groove 3121a do not overlap in the thickness direction Z, and the adhesive layer 342 and the second groove 3122a also do not overlap in the thickness direction Z.

[0124] To reduce the risk of external impurities passing through the first groove 3121a and the second groove 3122a, the depths of the first groove 3121a and the second groove 3122a are relatively small; however, due to its own characteristics, the adhesive layer 342 may fill into the first groove 3121a or the second groove 3122a, causing the first groove 3121a or the second groove 3122a to be blocked, affecting the airtightness test of the battery cell.

[0125] In this embodiment, the first groove 3121a is staggered from the adhesive layer 342, and the second groove 3122a is staggered from the adhesive layer 342. This can reduce the risk of the adhesive layer 342 clogging the first groove 3121a and the second groove 3122a.

[0126] For example, the adhesive layer 342 forms a notch 342a in the portion corresponding to the first groove 3121a to avoid the first groove 3121a; the adhesive layer 342 also forms a notch 342a in the portion corresponding to the second groove 3122a to avoid the second groove 3122a.

[0127] Figure 11 This is a top view schematic diagram of the end cap of the end cap assembly provided in some embodiments of this application; Figure 12 for Figure 11 Enlarged view of point D in the circle; Figure 13 for Figure 12 A schematic cross-sectional view along the cutting line EE.

[0128] like Figures 11 to 13 As shown, on the circumferential X of the through hole 313, the first groove 3121a and the second groove 3122a are offset.

[0129] This embodiment can increase the distance between the first groove 3121a and the second groove 3122a in the circumferential X direction, extend the path of external impurities from the second groove 3122a to the first groove 3121a, and increase the difficulty for external impurities to enter the through hole 313.

[0130] In some embodiments, the first groove 3121a and the second groove 3122a are misaligned by an angle α of 90°-180° in the circumferential direction X of the through hole 313. The angle α is used as a reference to characterize the relative position of the first groove 3121a and the second groove 3122a.

[0131] For example, the angle α is 90°, 120°, 150° or 180°.

[0132] In this embodiment, the spacing between the first groove 3121a and the second groove 3122a in the circumferential X direction can be guaranteed, increasing the difficulty for external impurities to enter the through hole 313.

[0133] In some embodiments, the main body 311 is provided with an injection hole 3111 for injecting electrolyte into the battery cell 7. A first groove 3121a is located between the through hole 313 and the injection hole 3111, and a second groove 3122a is located on the side of the through hole 313 opposite to the injection hole 3111.

[0134] During the production of battery cell 7, the electrolyte injection equipment injects electrolyte into the interior of battery cell 7 through injection hole 3111. During the injection process, the electrolyte is at high speed, which poses a risk of splashing outwards.

[0135] In this embodiment, the second groove 3122a is disposed on the side of the through hole 313 away from the injection hole 3111. In this way, the electrolyte splashed out from the injection hole 3111 will be blocked by the second protrusion 3122 and the protective sheet, so that the electrolyte is less likely to splash into the second groove 3122a, reducing the risk of electrolyte entering the through hole 313 and improving the safety of the battery cell.

[0136] In some embodiments, the battery cell also includes a seal (not shown) which is attached to the end cap 31 after the process associated with the injection port 3111 is completed, to seal the injection port 3111.

[0137] In some embodiments, the first recess 314 includes a first portion 3141 and a second portion 3142 disposed along the circumferential direction X of the through hole 313. The first portion 3141 communicates with a first groove 3121a, and the second portion 3142 communicates with a second groove 3122a. In the thickness direction Z, the depth of the first portion 3141 is less than the depth of the second portion 3142.

[0138] The first part 3141 and the second part 3142 can be directly connected, or they can be indirectly connected through the gas portion of the first recess 314.

[0139] The depth of the first part 3141 is less than the depth of the second part 3142, so the bottom surface of the first part 3141 is higher than the bottom surface of the second part 3142.

[0140] External impurities will first enter the second part 3142 through the second groove 3122a. Since the depth of the second part 3142 is greater than the depth of the first part 3141, external impurities will first accumulate in the second part 3142 and will not easily enter the first part 3141 directly. This increases the difficulty for external impurities to enter the through hole 313 through the first groove 3121a, reduces the risk of corrosion of the pressure relief mechanism, and improves safety.

[0141] In some embodiments, the first recess 314 includes a third portion 3143, which connects the first portion 3141 and the second portion 3142. In the thickness direction Z, the depth of the third portion 3143 is greater than the depth of the first portion 3141 and less than the depth of the second portion 3142.

[0142] In the circumferential direction X of the through hole 313, the third part 3143 is located between the first part 3141 and the second part 3142. The bottom surface of the third part 3143 is higher than the bottom surface of the second part 3142 and the bottom surface of the first part 3141.

[0143] In this embodiment, the bottom surface of the first recess 314 is formed with multiple steps. In this way, the difficulty for impurities to move in the first recess 314 toward the first groove 3121a gradually increases, thereby reducing the difficulty for impurities to enter the through hole 313 through the first groove 3121a, reducing the risk of corrosion of the pressure relief mechanism 33, and improving safety.

[0144] In some embodiments, in the circumferential direction X of the through hole 313, the depth of at least a portion of the first portion 3141 gradually decreases in the direction close to the first groove 3121a.

[0145] In this embodiment, even if external impurities enter the first part 3141, the difficulty for them to move towards the first groove 3121a in the first part 3141 gradually increases, thereby reducing the difficulty for impurities to enter the through hole 313 through the first groove 3121a, reducing the risk of corrosion of the pressure relief mechanism 33, and improving safety.

[0146] For example, the bottom surface of the first part 3141 can be a slope or a curved surface.

[0147] In some embodiments, the first recess 314 includes a fourth portion 3144, which connects the first portion 3141 and the third portion 3143. In the thickness direction Z, the depth of the fourth portion 3144 is greater than the depth of the first portion 3141 and less than the depth of the third portion 3143.

[0148] In some embodiments, both the fourth portion 3144 and the third portion 3143 are provided in pairs. Exemplarily, the first portion 3141, one fourth portion 3144, one third portion 3143, the second portion 3142, another third portion 3143, and another fourth portion 3144 are arranged sequentially along the circumferential direction X to form an annular first recess 314.

[0149] In some embodiments, the bottom surfaces of the second portion 3142, the third portion 3143, and the fourth portion 3144 are all planar.

[0150] Figure 14 for Figure 12 Another sectional view along the section line EE.

[0151] like Figure 12 and Figure 14As shown, in some embodiments, in the circumferential direction X of the through hole 313, the depth of at least a portion of the first recess 314 gradually decreases in the direction close to the first groove 3121a.

[0152] In this embodiment, even if external impurities enter the first recess 314, the difficulty for them to move in the first recess 314 toward the first groove 3121a gradually increases, thereby reducing the difficulty for impurities to enter the through hole 313 through the first recess 314, reducing the risk of corrosion of the pressure relief mechanism 33, and improving safety.

[0153] In some embodiments, the depth of the third portion 3143 gradually decreases along the direction close to the first groove 3121a in the circumferential X direction of the through hole 313.

[0154] In some embodiments, the depth of the fourth portion 3144 gradually decreases along the direction close to the first groove 3121a in the circumferential X direction of the through hole 313.

[0155] In some embodiments, the depth at which the fourth portion 3144 connects to the end of the first portion 3141 may be equal to the depth at which the first portion 3141 connects to the end of the fourth portion 3144. The depth at which the fourth portion 3144 connects to the end of the third portion 3143 may be equal to the depth at which the third portion 3143 connects to the end of the fourth portion 3144. The depth at which the third portion 3143 connects to the end of the second portion 3142 may be equal to the depth at which the second portion 3142 connects to the end of the third portion 3143.

[0156] Figure 15 This is a schematic flowchart illustrating a manufacturing method provided in some embodiments of this application.

[0157] like Figure 15 As shown, the manufacturing method of the end cap assembly in this application includes: S100. An end cap is provided, the end cap including a main body and a protrusion, the protrusion protruding from the main body along the thickness direction of the end cap, the end cap having a through hole that passes through the main body and the protrusion, the protrusion including a first protrusion and a second protrusion, the first protrusion surrounding the through hole, the second protrusion surrounding the outside of the first protrusion, a first recess being formed between the first protrusion and the second protrusion, the first recess communicating with the through hole and the external space of the end cap; S200, Provide a pressure relief mechanism and set the pressure relief mechanism on the side of the main body away from the protrusion, and the pressure relief mechanism covers the through hole; S300, A protective sheet is provided and attached to the surface of the protrusion away from the main body, and the protective sheet covers the through hole; The pressure relief mechanism is configured to be actuated when the internal pressure of a battery cell reaches a threshold to release the internal pressure through a through-hole.

[0158] It should be noted that the relevant structure of the end cap assembly manufactured by the above-described end cap assembly manufacturing method can be found in the end cap assemblies provided in the above embodiments.

[0159] When manufacturing the end cap assembly based on the above-described manufacturing method, the steps do not necessarily need to be performed sequentially. That is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously. For example, steps S200 and S300 can be performed in any order and can be performed simultaneously.

[0160] Figure 16 A schematic block diagram of a manufacturing system for an end cap assembly provided in some embodiments of this application.

[0161] like Figure 16 As shown, the end cap assembly manufacturing system 90 of this application embodiment includes a first providing device 91, a second providing device 92, and a third providing device 93. The first providing device 91 provides an end cap, which includes a main body and a protrusion. The protrusion protrudes from the main body along the thickness direction of the end cap. The end cap has a through hole that passes through the main body and the protrusion. The protrusion includes a first protrusion and a second protrusion. The first protrusion surrounds the through hole, and the second protrusion surrounds the outside of the first protrusion. A first recess is formed between the first and second protrusions, and the first recess communicates with the through hole and the external space of the end cap. The second providing device 92 provides a pressure relief mechanism and is disposed on the side of the main body opposite to the protrusion, and the pressure relief mechanism covers the through hole. The third providing device 93 provides a protective sheet and is attached to the surface of the protrusion opposite to the main body, and the protective sheet covers the through hole. The pressure relief mechanism is configured to be actuated when the internal pressure of the battery cell reaches a threshold to release the internal pressure through the through hole.

[0162] The structure of the end cap assembly manufactured by the above manufacturing system can be found in the end cap assemblies provided in the above embodiments.

[0163] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0164] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An end cap assembly for a single battery cell, comprising: An end cap includes a main body and a protrusion, the protrusion protruding from the main body along the thickness direction of the end cap, and the end cap having a through hole that passes through the main body and the protrusion. A pressure relief mechanism, disposed on the side of the main body opposite to the protrusion and covering the through-hole, is configured to be actuated when the internal pressure of the battery cell reaches a threshold to release the internal pressure through the through-hole; and A protective sheet is attached to the surface of the protrusion opposite to the main body and covers the through hole; The protrusion includes a first protrusion and a second protrusion. The first protrusion surrounds the through hole, and the second protrusion surrounds the outside of the first protrusion. A first recess is formed between the first protrusion and the second protrusion. A first groove is provided on the surface of the first protrusion facing away from the main body. The first groove is used to connect the through hole and the first recess. A second groove is provided on the surface of the second protrusion facing away from the main body. The second groove is used to connect the first recess and the external space of the end cap.

2. The end cap assembly according to claim 1, wherein, In the thickness direction, the depth of both the first groove and the second groove is less than the depth of the first recess.

3. The end cap assembly according to claim 1, wherein, The first groove and the second groove are misaligned in the circumferential direction of the through hole.

4. The end cap assembly according to claim 3, wherein, In the circumferential direction of the through hole, the first groove and the second groove are misaligned by an angle of 90°-180°.

5. The end cap assembly according to claim 3, wherein, The main body is provided with an injection hole, which is used to inject electrolyte into the battery cell. The first groove is located between the through hole and the injection hole, and the second groove is located on the side of the through hole opposite to the injection hole.

6. The end cap assembly according to any one of claims 1-5, wherein, The protective sheet includes a base layer and an adhesive layer. The base layer covers the through hole, and the adhesive layer is disposed on the surface of the base layer facing the protrusion and is bonded to the first protrusion and the second protrusion. The adhesive layer is not provided in the area of ​​the base layer opposite to the first groove in the thickness direction, and the adhesive layer is not provided in the area of ​​the base layer opposite to the second groove in the thickness direction.

7. The end cap assembly according to any one of claims 1-5, wherein, The first recess includes a first portion and a second portion disposed circumferentially along the through hole, the first portion being used to communicate with the first groove, and the second portion being used to communicate with the second groove; In the thickness direction, the depth of the first portion is less than the depth of the second portion.

8. The end cap assembly according to claim 7, wherein, The first recess includes a third portion, which connects the first portion and the second portion; In the thickness direction, the depth of the third portion is greater than the depth of the first portion and less than the depth of the second portion.

9. The end cap assembly according to claim 7, wherein, In the circumferential direction of the through hole, the depth of at least a portion of the first portion gradually decreases along the direction close to the first groove.

10. The end cap assembly according to any one of claims 1-5, wherein, In the circumferential direction of the through hole, the depth of at least a portion of the first recess gradually decreases in the direction close to the first groove.

11. The end cap assembly according to any one of claims 1-5, wherein, The surface of the first protrusion facing away from the main body is flush with the surface of the second protrusion facing away from the main body.

12. The end cap assembly according to any one of claims 1-5, wherein, At least a portion of the first recess is recessed into the main body portion.

13. The end cap assembly according to any one of claims 1-5, wherein, The protective sheet covers the first recess.

14. A single battery cell, comprising: The shell has an opening; Electrode assembly, housed within the housing; as well as According to any one of claims 1-13, the end cap is used to close the opening, and the protrusion is located on the side of the body portion opposite to the electrode assembly.

15. A battery comprising a plurality of battery cells according to claim 14.

16. An electrical device comprising a battery cell according to claim 14, the battery cell being used to provide electrical energy.

17. A method for manufacturing an end cap assembly, comprising: An end cap is provided, the end cap including a main body and a protrusion, the protrusion protruding from the main body along the thickness direction of the end cap, the end cap having a through hole that passes through the main body and the protrusion, the protrusion including a first protrusion and a second protrusion, the first protrusion surrounding the through hole, the second protrusion surrounding the outside of the first protrusion, a first recess being formed between the first protrusion and the second protrusion, a first groove being provided on the surface of the first protrusion facing away from the main body, the first groove being used to connect the through hole and the first recess, and a second groove being provided on the surface of the second protrusion facing away from the main body, the second groove being used to connect the first recess and the external space of the end cap; A pressure relief mechanism is provided and disposed on the side of the main body opposite to the protrusion, and the pressure relief mechanism covers the through hole; A protective sheet is provided and attached to the surface of the protrusion opposite to the main body, and the protective sheet covers the through hole; The pressure relief mechanism is configured to be actuated when the internal pressure of a battery cell reaches a threshold to release the internal pressure through the through-hole.

18. A manufacturing system for an end cap assembly, comprising: A first providing device is used to provide an end cap, the end cap including a main body and a protrusion, the protrusion protruding from the main body along the thickness direction of the end cap, the end cap having a through hole that passes through the main body and the protrusion, the protrusion including a first protrusion and a second protrusion, the first protrusion surrounding the through hole, the second protrusion surrounding the outside of the first protrusion, a first recess being formed between the first protrusion and the second protrusion, a first groove being provided on the surface of the first protrusion facing away from the main body, the first groove being used to connect the through hole and the first recess, and a second groove being provided on the surface of the second protrusion facing away from the main body, the second groove being used to connect the first recess and the external space of the end cap; A second providing device is used to provide a pressure relief mechanism, and the pressure relief mechanism is disposed on the side of the main body opposite to the protrusion, and the pressure relief mechanism covers the through hole; A third providing device is used to provide a protective sheet and attach the protective sheet to the surface of the protrusion opposite to the main body, and the protective sheet covers the through hole; The pressure relief mechanism is configured to be actuated when the internal pressure of a battery cell reaches a threshold to release the internal pressure through the through-hole.

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