Battery cell and manufacturing method and system thereof, battery and electric device

Abstract

The embodiments of the present application provide a battery cell and a manufacturing method and system thereof, a battery, and an electrical device. The battery cell includes: a battery box, including a first wall and a pressure relief mechanism, the pressure relief mechanism is arranged on the first wall, and the pressure relief mechanism is used to actuate to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold value; a protective member, located on the outside of the first wall, the protective member includes a main body, a shielding part, and a weak part, the main body is used to connect the first wall, the shielding part is used to shield the pressure relief mechanism, the weak part is used to connect the main body and the shielding part, and the weak part is configured to rupture when the pressure relief mechanism is actuated to disconnect the main body and the shielding part. The shielding part can block the emissions released by other battery cells and reduce the risk of the pressure relief mechanism being melted through by the emissions. When the single battery cell has thermal runaway, the weak part ruptures under the action of high-temperature and high-pressure substances to allow the high-temperature and high-pressure substances to be discharged in time.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and more specifically, to a battery cell and a manufacturing method and system thereof, a battery, and an electrical device. Background Art

[0002] Rechargeable batteries, also known as secondary batteries, are batteries that can be recharged to activate the active material after the battery is discharged and continue to be used. Rechargeable batteries are widely used in electronic devices such as mobile phones, laptops, battery cars, electric cars, electric airplanes, electric boats, electric toy cars, electric toy boats, electric toy airplanes, and electric tools, etc.

[0003] In the development of battery technology, in addition to improving battery performance, safety is also an issue that cannot be ignored. If the safety of the battery cannot be guaranteed, the battery cannot be used. Therefore, how to enhance the safety of the battery is a technical problem that needs to be solved urgently in battery technology. Summary of the invention

[0004] The present application provides a battery cell and a manufacturing method and system thereof, a battery, and an electrical device, which can enhance the safety of the battery.

[0005] In a first aspect, an embodiment of the present application provides a battery cell, comprising: a battery box, comprising a first wall and a pressure relief mechanism, the pressure relief mechanism being arranged on the first wall, the pressure relief mechanism being used to be actuated to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold value; a protective member, being located on the outside of the first wall, the protective member comprising a main body, a shielding portion and a weak portion, the main body being used to connect to the first wall, the shielding portion being used to shield the pressure relief mechanism, the weak portion being used to connect the main body and the shielding portion, and the weak portion being configured to rupture when the pressure relief mechanism is actuated to disconnect the main body and the shielding portion.

[0006] In the embodiment of the present application, the shielding part of the protective component of the single cell can block the emissions released by other battery cells, reduce the possibility of the pressure relief mechanism being melted through by the emissions released by other battery cells, and reduce the safety risk. On the other hand, when the single cell has thermal runaway, the pressure relief mechanism is actuated to release the high-temperature and high-pressure substances inside. At the same time, the weak part is ruptured under the action of the high-temperature and high-pressure substances, thereby forming a channel for the high-temperature and high-pressure substances to be discharged on the protective component, so that the high-temperature and high-pressure substances can be discharged in time, reducing the safety risk.

[0007] In some embodiments, the battery cell further includes an adhesive member, and the protection member is connected to the first wall through the adhesive member.

[0008] In some embodiments, the surface of the main body facing the first wall is provided with an adhesive member, and the surface of the shielding part facing the first wall and the surface of the weak part facing the first wall are not provided with an adhesive member. This can reduce the risk of the adhesive member connecting the shielding part to the main body when the weak part is broken.

[0009] In some embodiments, the melting point of the protection component is greater than the melting point of the pressure relief mechanism. The protection component has a higher melting point and can withstand higher temperatures, thereby reducing the risk of being melted through by emissions and improving safety performance.

[0010] In some embodiments, the melting point of the protective member is not less than 600 degrees.

[0011] In some embodiments, the material of the protection component includes at least one of mica, rubber and ceramic.

[0012] In some embodiments, the thickness of the shielding portion is smaller than the thickness of the main body portion.

[0013] In some embodiments, the pressure relief mechanism is provided with a first groove, and the pressure relief mechanism is used to rupture at the first groove to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold value, and the shielding portion completely covers the first groove.

[0014] In some embodiments, the shielding portion protrudes outward from the main body along a direction perpendicular to the first wall, so that the distance between the shielding portion and the pressure relief mechanism can be increased in the direction perpendicular to the first wall, thereby extending the heat transfer path between the shielding portion and the pressure relief mechanism and reducing the heat transferred to the pressure relief mechanism.

[0015] In some embodiments, a protrusion is provided on the outer surface of the first wall, and along a direction perpendicular to the first wall, the shielding portion is located on a side of the protrusion away from the pressure relief mechanism.

[0016] In some embodiments, the battery cell further comprises a protective film, which is disposed on the surface of the protrusion facing the shielding portion and covers the pressure relief mechanism. The protective film can block external impurities such as dust and water vapor and protect the pressure relief mechanism.

[0017] In some embodiments, the shielding portion presses the protective film tightly, and the shielding portion and the protrusion clamp the protective film to reduce the risk of the protective film falling off.

[0018] In some embodiments, a plurality of through openings are provided between the main body and the shielding portion, the weak portion includes a plurality of sub-weak areas, and the plurality of sub-weak areas and the plurality of openings are alternately provided along the circumference of the shielding portion. The protective member can reduce the overall strength of the weak portion by providing the openings, and when a high-temperature and high-pressure material impacts the shielding portion, the sub-weak areas of the weak portion can be destroyed in time.

[0019] In some embodiments, the thickness of the sub-weak area is less than or equal to the thickness of the main body; and / or the thickness of the sub-weak area is less than or equal to the thickness of the shielding portion.

[0020] In some embodiments, a second groove is provided on a side surface of the protective member away from the first wall, and the weak part is the bottom wall of the second groove; and / or a second groove is provided on a side surface of the protective member close to the first wall, and the weak part is the bottom wall of the second groove. By providing the second groove, the strength of the weak part can be reduced, and the weak part can be broken in time when impacted by high-temperature and high-pressure materials.

[0021] In some embodiments, the second groove is an annular groove surrounding the shielding portion. Correspondingly, the weak portion is annular and arranged around the edge of the shielding portion. When the shielding portion is impacted by a high-temperature and high-pressure substance, each part of the weak portion can be broken, thereby increasing the discharge rate of the high-temperature and high-pressure substance.

[0022] In some embodiments, the thickness of the weakened portion is 0.08 mm to 0.3 mm.

[0023] In some embodiments, the battery box includes: a shell having a accommodating cavity and an opening; an end cover assembly including a cover plate and an electrode terminal, the cover plate covers the opening of the shell, the electrode terminal is arranged on the cover plate, and the first wall is the cover plate.

[0024] In some embodiments, the battery cell further includes an electrode assembly, and the electrode assembly is accommodated in the accommodation cavity.

[0025] In a second aspect, an embodiment of the present application provides a battery, which includes a box and at least one battery cell according to the first aspect, and the battery cell is accommodated in the box.

[0026] In a third aspect, an embodiment of the present application provides an electrical device, which is configured to receive electrical energy provided by the battery of the second aspect.

[0027] In a fourth aspect, an embodiment of the present application provides a method for manufacturing a battery cell, comprising: providing an end cap assembly, the end cap assembly comprising a cover plate, an electrode terminal and a pressure relief mechanism, the pressure relief mechanism and the electrode terminal being arranged on the cover plate, the pressure relief mechanism being used to actuate to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold value; providing an electrode assembly, and connecting the electrode assembly to the electrode terminal; providing a shell, the shell having a accommodating cavity and an opening; placing the electrode assembly connected to the electrode terminal into the accommodating cavity, and then connecting the cover plate to the shell to close the opening of the shell; providing a protective member, the protective member comprising a main body, a shielding portion and a weak portion, the weak portion being used to connect the main body and the shielding portion, and the weak portion being configured to rupture when the pressure relief mechanism is actuated to disconnect the main body and the shielding portion; arranging the protective member on the outside of the cover plate, and connecting the main body to the cover plate and the shielding portion to shield the pressure relief mechanism.

[0028] In a fifth aspect, an embodiment of the present application provides a manufacturing system for a battery cell, comprising: a first providing device for providing an end cap assembly, the end cap assembly comprising a cover plate, an electrode terminal and a pressure relief mechanism, the pressure relief mechanism and the electrode terminal being arranged on the cover plate, the pressure relief mechanism being used to actuate to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold value; a second providing device for providing an electrode assembly; a first assembling device for connecting the electrode assembly to the electrode terminal; a third providing device for providing a shell, the shell having a accommodating cavity and an opening; a second assembling device for placing the electrode assembly connected to the electrode terminal into the accommodating cavity, and connecting the cover plate to the shell to close the opening of the shell; a fourth providing device for providing a protective member, the protective member comprising a main body, a shielding portion and a weak portion, the weak portion being used to connect the main body and the shielding portion, and the weak portion being configured to rupture when the pressure relief mechanism is actuated to disconnect the main body and the shielding portion; a third assembling device for arranging the protective member on the outside of the cover plate, and connecting the main body to the cover plate and the shielding portion to shield the pressure relief mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without paying creative work.

[0030] Figure 1 A schematic diagram of the structure of a vehicle according to an embodiment of the present application;

[0031] Figure 2 This is a schematic diagram of the structure of a battery according to an embodiment of the present application;

[0032] Figure 3 This is a schematic diagram of the structure of a battery module according to an embodiment of the present application;

[0033] Figure 4 This is a schematic diagram of the structure of a battery cell according to an embodiment of the present application;

[0034] Figure 5 for Figure 4 An exploded schematic diagram of a battery cell is shown;

[0035] Figure 6 for Figure 4 A schematic cross-sectional view of a battery cell taken along line AA is shown;

[0036] Figure 7 for Figure 6 An enlarged view of the battery cell shown at box B;

[0037] Figure 8 for Figure 7 The enlarged view at the circle C;

[0038] Fig. 9 This is a schematic structural diagram of a protective component according to an embodiment of the present application;

[0039] Fig.10 A schematic diagram of the structure of another protective component according to an embodiment of the present application;

[0040] Fig.11 for Fig. 9 An enlarged view of the protective member shown at the circle D;

[0041] Fig.12 A schematic top view of a protective component according to an embodiment of the present application;

[0042] Fig.13 for Fig.12 A schematic cross-sectional view of the protective member shown along line EE;

[0043] Fig.14 for Fig.12 Another schematic cross-sectional view of the protective member shown along line EE;

[0044] Fig.15 for Fig.12 Another schematic cross-sectional view of the protective member taken along line EE is shown;

[0045] Fig.16 A schematic diagram of a process for manufacturing a battery cell according to an embodiment of the present application;

[0046] Fig.17 A schematic structural diagram of a battery cell manufacturing system according to an embodiment of the present application.

[0047] In the drawings, the drawings are not drawn to scale. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0049] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0050] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0051] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0052] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0053] The term "multiple" as used in the present application refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple sheets" refers to more than two sheets (including two sheets).

[0054] In the present application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries or magnesium-ion batteries, etc., and the embodiments of the present application do not limit this. Battery cells may be cylindrical, flat, rectangular or other shapes, etc., and the embodiments of the present application do not limit this. Battery cells are generally divided into three types according to the packaging method: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of the present application do not limit this.

[0055] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module or a battery pack. The battery generally includes a box for encapsulating one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

[0056] The battery cell includes an electrode assembly and an electrolyte. The electrode assembly is composed of a positive electrode sheet, a negative electrode sheet and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector. The current collector not coated with the positive electrode active material layer protrudes from the current collector coated with the positive electrode active material layer. The current collector not coated with the positive electrode active material layer serves as the positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material may 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 is coated on the surface of the negative electrode current collector. The current collector not coated with the negative electrode active material layer protrudes from the current collector coated with the negative electrode active material layer. The current collector not coated with the negative electrode active material layer serves as the negative electrode tab. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon or silicon, etc. In order to ensure that a large current can pass without melting, the number of positive pole ears is multiple and stacked together, and the number of negative pole ears is multiple and stacked together. The material of the diaphragm can be PP or PE, etc. In addition, the electrode assembly can be a winding structure or a laminated structure, and the embodiments of the present application are not limited to this. The development of battery technology must consider many design factors at the same time, such as performance parameters such as energy density, cycle life, discharge capacity, and charge and discharge rate. In addition, the safety of the battery also needs to be considered.

[0057] For battery cells, the main safety hazards come from the charging and discharging process, as well as the appropriate ambient temperature design. In order to effectively avoid unnecessary losses, there are generally at least three protection measures for battery cells. Specifically, the protection measures include at least switching elements, selecting appropriate isolation membrane materials, and pressure relief mechanisms. Switching elements refer to elements that can stop the battery from charging or discharging when the temperature or resistance in the battery cell reaches a certain threshold. The isolation membrane is used to isolate the positive and negative electrodes. When the temperature rises to a certain value, it can automatically dissolve the micron-level (even nano-level) micropores attached to it, so that metal ions cannot pass through the isolation membrane, terminating the internal reaction of the battery cell.

[0058] The pressure relief mechanism refers to an element or component that is actuated to release the internal pressure or temperature when the internal pressure or temperature of the battery cell reaches a predetermined threshold. The threshold design varies according to different design requirements. The threshold may depend on one or more materials of the positive electrode plate, negative electrode plate, electrolyte and isolation membrane in the battery cell. The pressure relief mechanism can take the form of an explosion-proof valve, an air valve, a pressure relief valve or a safety valve, and can specifically adopt pressure-sensitive or temperature-sensitive elements or structures, that is, when the internal pressure or temperature of the battery cell reaches a predetermined threshold, the pressure relief mechanism performs an action or a weak structure provided in the pressure relief mechanism ruptures, thereby forming an opening or channel for the internal pressure or temperature to be released.

[0059] The "actuation" mentioned in this application means that the pressure relief mechanism is in action or activated to a certain state, so that the internal pressure and temperature of the battery cell can be released. The action produced by the pressure relief mechanism may include but is not limited to: at least a part of the pressure relief mechanism is ruptured, broken, torn or opened, etc. When the pressure relief mechanism is actuated, the high-temperature and high-pressure substances inside the battery cell will be discharged from the actuated part as emissions. In this way, the battery cell can be depressurized under controllable pressure or temperature, thereby avoiding potential more serious accidents.

[0060] The emissions from the battery cells mentioned in this application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of the isolation membrane, high-temperature and high-pressure gas generated by the reaction, flames, etc.

[0061] The pressure relief mechanism on the battery cell has an important impact on the safety of the battery. For example, when a short circuit or overcharge occurs, thermal runaway may occur inside the battery cell, causing a sudden increase in pressure or temperature. In this case, the pressure relief mechanism can be activated to release the internal pressure and temperature to prevent the battery cell from exploding or catching fire.

[0062] In the current design of the pressure relief mechanism, the main focus is on releasing the high pressure and high heat inside the battery cell, that is, discharging the emissions to the outside of the battery cell. However, in order to ensure the output voltage or current of the battery, multiple battery cells are often required and the multiple battery cells are electrically connected through a busbar. The emissions discharged from the inside of the battery cell may cause the remaining battery cells to short-circuit. For example, the emissions spread to other normal battery cells. Under the action of high temperature, the emissions can easily melt through the pressure relief mechanism of the normal battery cell and enter the electrode assembly, causing the originally normal battery cell to short-circuit and thermal runaway, further exacerbating safety issues.

[0063] In view of this, an embodiment of the present application provides a technical solution, in which a protective component is provided in the pressure relief mechanism of the battery cell to protect the pressure relief mechanism, prevent the pressure relief mechanism from being melted through, reduce the risk of short circuit, and improve the safety of the battery.

[0064] The technical solutions described in the embodiments of the present application are applicable to various devices that use batteries, such as mobile phones, portable devices, laptop computers, electric vehicles, electric toys, electric tools, electric vehicles, ships and spacecraft, for example, spacecraft include airplanes, rockets, space shuttles and spacecraft, etc.

[0065] It should be understood that the technical solutions described in the embodiments of the present application are not limited to the devices described above, but can also be applied to all devices using batteries. However, for the sake of simplicity, the following embodiments are described using electric vehicles as examples.

[0066] For example, Figure 1 As shown, it is a schematic diagram of the structure of a vehicle 1 according to an embodiment of the present application. The vehicle 1 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 2, a controller 3 and a motor 4 may be arranged inside the vehicle 1, and the controller 3 is used to control the battery 2 to supply power to the motor 4. For example, a battery 2 may be arranged at the bottom, front or rear of the vehicle 1. The battery 2 may be used to power the vehicle 1. For example, the battery 2 may be used as an operating power source for the vehicle 1, for the circuit system of the vehicle 1, for example, for the working power requirements during the start-up, navigation and operation of the vehicle 1. In another embodiment of the present application, the battery 2 may not only be used as an operating power source for the vehicle 1, but also as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0067] In order to meet different power requirements, the battery may include multiple battery cells, wherein the multiple battery cells may be connected in series, in parallel, or in a hybrid connection, wherein the hybrid connection refers to a mixture of series and parallel connections. The battery may also be referred to as a battery pack. Optionally, multiple battery cells may be connected in series, in parallel, or in a hybrid connection to form a battery module, and multiple battery modules may be connected in series, in parallel, or in a hybrid connection to form a battery. In other words, multiple battery cells may be directly connected to form a battery, or may be first connected to form a battery module, and then the battery module may be connected to form a battery.

[0068] For example, Figure 2 As shown in FIG. 1 , it is a schematic diagram of the structure of a battery 2 according to an embodiment of the present application. The battery 2 may include a plurality of battery cells 10. The battery 2 may also include a housing (or housing), the interior of the housing is a hollow structure, and the plurality of battery cells 10 are accommodated in the housing. Figure 2As shown, the box body may include two parts, which are respectively referred to as the first part 11 and the second part 12, and the first part 11 and the second part 12 are buckled together. The shapes of the first part 11 and the second part 12 may be determined according to the shapes of the combination of multiple battery cells 10, and the first part 11 and the second part 12 may both have an opening. For example, the first part 11 and the second part 12 may both be hollow cuboids and each has only one open face, the opening of the first part 11 and the opening of the second part 12 are arranged opposite to each other, and the first part 11 and the second part 12 are buckled together to form a box body with a closed chamber. Multiple battery cells 10 are connected in parallel, series or mixed and then placed in the box body formed by the buckling of the first part 11 and the second part 12.

[0069] Optionally, the battery 2 may also include other structures, which are not described one by one here. For example, the battery 2 may also include a busbar component, which is used to realize electrical connection between multiple battery cells 10, such as parallel connection, series connection or mixed connection. Specifically, the busbar component can realize electrical connection between battery cells 10 by connecting the electrode terminals of the battery cells 10. Furthermore, the busbar component can be fixed to the electrode terminals of the battery cells 10 by welding. The electrical energy of multiple battery cells 10 can be further led out through the box through a conductive mechanism. Optionally, the conductive mechanism may also belong to the busbar component.

[0070] The number of battery cells 10 can be set to any value according to different power requirements. Multiple battery cells 10 can be connected in series, parallel or mixed to achieve a larger capacity or power. Since the number of battery cells 10 included in each battery 2 may be large, in order to facilitate installation, the battery cells 10 can be grouped and each group of battery cells 10 forms a battery module. The number of battery cells 10 included in the battery module is not limited and can be set according to requirements. For example, Figure 3 is an example of a battery module. A battery may include a plurality of battery modules, which may be connected in series, in parallel or in a mixed manner.

[0071] Figure 4 This is a schematic structural diagram of a battery cell 10 according to an embodiment of the present application; Figure 5 for Figure 4 An exploded schematic diagram of a battery cell 10 is shown; Figure 6 for Figure 4 The battery cell 10 is shown as a cross-sectional view taken along line AA. Figure 7 for Figure 6 An enlarged view of the battery cell 10 at box B is shown.

[0072] like Figures 4 to 7As shown, the battery cell 10 includes an electrode assembly 101 and a battery box for accommodating the electrode assembly 101, and the battery box includes an end cap assembly 100 and a shell 102. The shell 102 has a accommodating cavity and an opening, and the electrode assembly 101 is accommodated in the accommodating cavity. For example, when the shell 102 is a hollow cuboid or a cube, one of the planes of the shell 102 is an open surface, that is, the plane does not have a wall body so that the inside and outside of the shell 102 are connected. When the shell 102 can be a hollow cylinder, the end face of the shell 102 is an open face, that is, the end face does not have a wall body so that the inside and outside of the shell 102 are connected. The end cap assembly 100 includes a cover plate 110, which covers the opening and is connected to the shell 102, thereby closing the opening of the shell 102, so that the electrode assembly 101 is placed in the closed cavity. The shell 102 is filled with an electrolyte, such as an electrolyte.

[0073] The end cap assembly 100 may also include two electrode terminals, which may be disposed on the cap plate 110. The cap plate 110 is generally in the shape of a flat plate, and the two electrode terminals are fixed on the flat surface of the cap plate 110, and the two electrode terminals are respectively a positive electrode terminal 121 and a negative electrode terminal 122. Each electrode terminal is provided with a corresponding connecting member 103, or may also be referred to as a current collecting member, which is located between the cap plate 110 and the electrode assembly 101, and is used to electrically connect the electrode assembly 101 and the electrode terminal.

[0074] Each electrode assembly 101 has a first pole tab 101a and a second pole tab 101b. The polarities of the first pole tab 101a and the second pole tab 101b are opposite. For example, when the first pole tab 101a is a positive pole tab, the second pole tab 101b is a negative pole tab. The first pole tab 101a of one or more electrode assemblies 101 is connected to one electrode terminal through a connecting member 103, and the second pole tab 101b of one or more electrode assemblies 101 is connected to another electrode terminal through another connecting member 103. For example, the positive electrode terminal 121 is connected to the positive pole tab through a connecting member 103, and the negative electrode terminal 122 is connected to the negative pole tab through another connecting member 103.

[0075] In the battery cell 10 , the electrode assembly 101 may be provided as a single electrode assembly or multiple electrode assemblies according to actual use requirements; in some examples, two independent electrode assemblies 101 are provided in the battery cell 10 .

[0076] In some embodiments, the end cap assembly 100 may further include a lower insulating member 130, which is disposed on the side of the cover plate 110 facing the electrode assembly 101. The lower insulating member 130 can separate the cover plate 110 from the connecting member 103 and from the cover plate 110 from the electrode assembly 101, thereby reducing the risk of short circuit.

[0077] The battery box includes a first wall and a pressure relief mechanism 140, and the pressure relief mechanism 140 is disposed on the first wall. In some examples, the first wall may be a wall of the housing 102, for example, the housing 102 includes four side walls and a bottom wall connected to the four side walls, and the first wall may be either a bottom wall or a side wall. In other examples, the first wall is the cover plate 110. The pressure relief mechanism 140 may be a part of the first wall, or may be a separate structure from the first wall, for example, fixed to the first wall by welding.

[0078] The cover plate 110 of the embodiment of the present application has a through hole 111, and the through hole 111 penetrates the cover plate 110 along the thickness direction of the cover plate 110. The pressure relief mechanism 140 is connected to the cover plate 110 and covers the through hole 111. In the battery cell 10, the pressure relief mechanism 140 can seal the through hole 111 to separate the space on both sides of the cover plate 110, prevent the electrolyte from flowing out through the through hole 111, and improve the sealing performance of the battery cell 10.

[0079] The pressure relief mechanism 140 is used to actuate to release the internal pressure when the internal pressure or temperature of the battery cell 10 reaches a threshold value. When the battery cell 10 generates too much gas so that the internal pressure of the housing 102 increases and reaches a threshold value, or the internal reaction of the battery cell 10 generates heat, causing the internal temperature of the battery cell 10 to increase and reach a threshold value, the pressure relief mechanism 140 performs an action or the weak structure provided in the pressure relief mechanism 140 is broken, and the gas pressure and temperature are released outward through the opening of the pressure relief mechanism 140 and the through hole 111, thereby preventing the battery cell 10 from exploding.

[0080] The pressure relief mechanism 140 may be any possible pressure relief structure, which is not limited in the embodiments of the present application. For example, the pressure relief mechanism 140 may be a temperature-sensitive pressure relief mechanism, which is configured to melt when the internal temperature of the battery cell 10 provided with the pressure relief mechanism 140 reaches a threshold value; and / or, the pressure relief mechanism 140 may be a pressure-sensitive pressure relief mechanism, which is configured to rupture when the internal air pressure of the battery cell 10 provided with the pressure relief mechanism 140 reaches a threshold value.

[0081] The battery cell of the embodiment of the present application further includes a protective member 150, which is disposed on the outer side of the cover plate 110, that is, the protective member 150 is disposed on the side of the cover plate 110 away from the electrode assembly 101. The protective member 150 is used to shield the pressure relief mechanism 140 and the through hole 111 from the outside. The protective member 150 can completely shield the through hole 111, or only shield a portion of the through hole 111.

[0082] In the battery, when the pressure relief mechanism of a battery cell is actuated and releases emissions, the emissions spread to other normal battery cells. The protective component 150 on the normal battery cells can block the emissions, reduce the risk of emissions contacting the pressure relief mechanism 140 and melting through the pressure relief mechanism 140, reduce or prevent emissions from entering the electrode assembly 101, and reduce safety risks.

[0083] The inventors further discovered that although the protective component 150 of the battery cell 10 can shield the pressure relief mechanism 140 from the outside, reducing the risk of the pressure relief mechanism 140 being melted through by emissions released by other battery cells, when the battery cell 10 needs to release high-temperature and high-pressure substances inside due to thermal runaway, the protective component 150 is difficult to open quickly, resulting in the high-temperature and high-pressure substances being unable to be discharged in time, causing a safety risk.

[0084] In view of this, the protective member 150 provided in the embodiment of the present application includes a main body 151, a shielding portion 152 and a weak portion 153. The main body 151 is used to connect the cover plate 110 to fix the protective member 150 to the cover plate 110; the shielding portion 152 is used to shield the pressure relief mechanism 140 to block the emissions released by other battery cells and reduce the risk of the pressure relief mechanism 140 being melted by the emissions released by other battery cells. The weak portion 153 is used to connect the main body 151 and the shielding portion 152, and the weak portion 153 is configured to rupture when the pressure relief mechanism 140 is actuated to disconnect the main body 151 and the shielding portion 152.

[0085] The shielding portion 152 is used to shield the portion of the pressure relief mechanism 140 corresponding to the through hole 111. The shielding portion 152 may completely shield the through hole 111, or may only shield a portion of the through hole 111. In the thickness direction of the cover plate 110, the orthographic projection of the shielding portion 152 at least partially overlaps with the orthographic projection of the through hole 111. The orthographic projection of the through hole 111 refers to the area enclosed by the orthographic projection of the hole wall of the through hole 111 along the thickness direction.

[0086] The weak portion 153 can adopt various settings that facilitate the destruction of high-temperature and high-pressure materials, and the embodiments of the present application are not limited to this. The strength of the weak portion 153 is less than the strength of the shielding portion 152 and the strength of the main body 151. In this way, when the pressure relief mechanism 140 is actuated, the weak portion 153 can be broken to disconnect the connection between the main body 151 and the shielding portion 152. The protective member 150 can reduce the strength of the weak portion 153 by providing structures such as openings, grooves, and notches. Of course, the weak portion 153 can also be made of low-strength materials.

[0087] When the pressure relief mechanism 140 is actuated, the weak portion 153 is destroyed under the action of the high temperature and high pressure substance, thereby disconnecting the main body 151 and the shielding portion 152. The high temperature and high pressure substance may act directly on the weak portion 153, or transfer heat and pressure to the weak portion 153 through the shielding portion 152. In some examples, the weak portion 153 may be destroyed as a whole, and the shielding portion 152 loses the restraint of the main body 151, and is then flushed open by the high temperature and high pressure substance; at this time, the shielding portion 152 will no longer block the high temperature and high pressure substance, and a channel for the high temperature and high pressure substance to be discharged is formed on the protective member 150, and the high temperature and high pressure substance can be quickly discharged to the outside of the battery cell 10. In other examples, the weak portion 153 can be partially destroyed, and the protective member 150 can form a channel at the destroyed position of the weak portion 153, through which the high-temperature and high-pressure material can be discharged; in addition, the connecting force between the shielding portion 152 and the main body 151 is reduced, and the shielding portion 152 flips outward under the impact of the high-temperature and high-pressure material, thereby increasing the size of the channel and increasing the efficiency of the discharge of the high-temperature and high-pressure material.

[0088] On the one hand, the shielding portion 152 of the protective member 150 of the single battery 10 can block the emissions released by other battery cells, reducing the risk of the pressure relief mechanism 140 being melted by the emissions released by other battery cells. On the other hand, when the single battery 10 has thermal runaway, the pressure relief mechanism 140 is actuated to release the high-temperature and high-pressure substances inside. At the same time, the weak portion 153 is broken under the action of the high-temperature and high-pressure substances, and a channel for the high-temperature and high-pressure substances to be discharged is formed on the protective member 150, so that the high-temperature and high-pressure substances can be discharged in time, reducing safety risks.

[0089] In some embodiments of the present application, the melting point of the protective member 150 is greater than that of the pressure relief mechanism 140. Compared with the pressure relief mechanism 140, the protective member 150 has a higher melting point and can withstand higher temperatures, thereby reducing the risk of being melted through by emissions and improving safety performance.

[0090] In one embodiment of the present application, the melting point of the protective member 150 is not less than 600 degrees. At this time, the melting point of the protective member 150 is relatively high and is not easily melted through by the discharge. Optionally, the melting point of the protective member 150 is not less than 1000 degrees.

[0091] In some embodiments of the present application, the material of the protective member 150 includes at least one of mica, rubber and ceramic. Optionally, the protective member 150 is mica paper or mica board, which has the characteristics of insulation and high temperature resistance, can effectively block high temperature emissions, and play a role in protecting the pressure relief mechanism 140. Mica paper or mica board is thin, and when impacted by high temperature and high pressure materials, it can be broken in time at the weak part 153; at the same time, the mica paper or mica board is thin and light, and has little effect on the energy density of the battery cell.

[0092] In some embodiments of the present application, the protective member 150 can also play a role in heat insulation. The protective member 150 can at least isolate part of the emissions from the cover plate 110, thereby reducing the heat transferred to the cover plate 110, reducing the temperature rise of the battery cell 10, allowing the electrode assembly 101 to operate within a suitable temperature range, and improving the charge and discharge performance of the electrode assembly 101.

[0093] In some embodiments of the present application, the shielding portion 152 completely covers the through hole 111 along the thickness direction of the cover plate 110 , so that the shielding portion 152 can block emissions as much as possible and reduce the risk of emissions entering the through hole 111 .

[0094] The battery cell of the embodiment of the present application further includes an adhesive member 170, and the protective member 150 is connected to the cover plate 110 through the adhesive member 170. The adhesive member 170 may be adhesive-backed. Before being assembled to the cover plate 110, the protective member 150 may be bonded to the release paper through the adhesive member 170; when necessary, the protective member 150 and the adhesive member 170 are peeled off from the release paper and then bonded to the cover plate 110.

[0095] In some embodiments, the surface of the main body 151 facing the cover plate 110 is provided with an adhesive member 170. The adhesive member 170 fixes the main body 151 to the cover plate 110. The adhesive member 170 is sticky, softens at high temperatures and is not easy to break. If the adhesive member 170 is also provided on the shielding part 152 and the weak part 153, then when the weak part 153 is broken, the adhesive member 170 may connect the shielding part 152 to the main body 151, resulting in the failure of timely discharge of high-temperature and high-pressure substances. Therefore, the surface of the shielding part 152 facing the cover plate 110 and the surface of the weak part 153 facing the cover plate 110 are not provided with an adhesive member 170.

[0096] In some embodiments, there may be one adhesive member 170 ; in other embodiments, there may be a plurality of adhesive members 170 that are non-continuously arranged.

[0097] Figure 8 for Figure 7 Enlarged view at box C. Figure 8As shown, in some embodiments of the present application, in some embodiments, the pressure relief mechanism 140 is provided with a first groove 141, and the pressure relief mechanism 140 is used to rupture at the first groove 141 to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold value. The bottom wall of the first groove 141 is a weak structure formed on the pressure relief mechanism 140. When the internal pressure or temperature of the battery cell reaches a threshold value, the bottom wall of the first groove 141 is cracked and an opening is formed, and the gas pressure and temperature are released outward through the cracked opening of the pressure relief mechanism 140 and the through hole 111, thereby preventing the battery cell from exploding.

[0098] The bottom wall of the first groove 141 is relatively weak and is more likely to be melted through by the discharge. Therefore, in some embodiments, the shielding portion 152 completely covers the first groove 141, that is, in the thickness direction of the cover plate 110, the orthographic projection of the shielding portion 152 completely covers the orthographic projection of the first groove 141. This can reduce the risk of the discharge falling into the first groove 141 of the pressure relief mechanism 140 and reduce the possibility of the pressure relief mechanism 140 being melted through.

[0099] The shielding portion 152 protrudes outward from the main body 151 in a direction perpendicular to the cover plate 110. In this way, the embodiment of the present application can increase the distance between the shielding portion 152 and the pressure relief mechanism 140 in a direction perpendicular to the cover plate 110 (i.e., the thickness direction of the cover plate 110), thereby extending the heat transfer path between the shielding portion 152 and the pressure relief mechanism 140 and reducing the heat transferred to the pressure relief mechanism 140. In addition, in some examples, when the internal pressure or temperature of the battery cell reaches a threshold value, the pressure relief mechanism 140 may rupture at the bottom wall of the first groove 141, and the pressure relief mechanism 140 is folded upward along the portion set at the rupture to form an opening to discharge high-temperature and high-pressure substances. If the distance between the shielding portion 152 and the pressure relief mechanism 140 is too small, the shielding portion 152 may block the folding of the pressure relief mechanism 140, resulting in a small opening of the pressure relief mechanism 140, causing the high-temperature and high-pressure substances to fail to break through the shielding portion 152 in time. Therefore, by protruding the shielding portion 152 from the main body 151 , the distance between the shielding portion 152 and the pressure relief mechanism 140 can be increased, thereby preventing the shielding portion 152 from blocking the folding of the pressure relief mechanism 140 .

[0100] In some embodiments of the present application, the weak portion 153 extends from the edge of the shielding portion 152 toward the direction close to the cover plate 110 and is connected to the main body 151. The protective member 150 forms a recessed portion on the side of the shielding portion 152 facing the cover plate 110. The main body 151 and the shielding portion 152 are both flat and substantially perpendicular to the thickness direction of the cover plate 110. The weak portion 153 is bent at a preset angle relative to the shielding portion 152, such as Figure 8As shown, the weak portion 153 is approximately perpendicular to the shielding portion 152. Of course, the angle between the weak portion 153 and the shielding portion 152 can be set according to product requirements, for example, it can be 80 degrees to 160 degrees, specifically, it can be 90 degrees, 120 degrees, 150 degrees, etc., which is not limited here.

[0101] In some embodiments of the present application, the cover plate 110 further has a receiving groove 112, which is recessed from the surface of the cover plate 110 facing the electrode assembly 101, and the receiving groove 112 is arranged around the through hole 111. The pressure relief mechanism 140 is at least partially accommodated in the receiving groove 112. The receiving groove 112 can play a positioning role, which facilitates the assembly of the pressure relief mechanism 140 and the cover plate 110.

[0102] In some embodiments of the present application, the cover plate 110 includes a cover plate body 114 and a protrusion 113 connected to the cover plate body 114. Along the direction perpendicular to the cover plate 110, the shielding portion 152 is located on the side of the protrusion 113 away from the pressure relief mechanism 140. In some examples, the protrusion 113 is located between the shielding portion 152 and the cover plate body 114, and the "between" refers to the spatial position relationship between the protrusion 113, the shielding portion 152 and the cover plate body 114 in the thickness direction of the cover plate 110, and the shielding portion 152 and the protrusion 113 are not required to overlap in the thickness direction. The cover plate body 114 is generally flat. The protrusion 113 protrudes relative to the surface of the cover plate body 114 facing the protective member 150. The through hole 111 runs through the cover plate body 114 and the protrusion 113. The through hole 111 includes an inner section penetrating the cover plate body 114 and an outer section penetrating the protrusion 113 , and the protrusion 113 includes a side wall surrounding the outer section. The protrusion 113 extends into the recess of the protection member 150 .

[0103] In some embodiments of the present application, along a direction parallel to the cover plate body 114, the weak portion 153 is located on the side of the protrusion 113 away from the through hole 111, and the protrusion 113 can separate the weak portion 153 from the through hole 111. Even if a portion of the weak portion 153 is melted through by emissions, the protrusion 113 can also play a role in blocking emissions, thereby reducing or preventing emissions from entering the through hole 111.

[0104] The protrusion 113 can also strengthen the strength of the cover plate 110 at the through hole 111 and reduce deformation of the cover plate 110. In some examples, the receiving groove 112 can be formed by pressing the cover plate 110, and after the cover plate 110 is pressed, the protrusion 113 is formed on the cover plate 110.

[0105] In some embodiments of the present application, the battery cell 10 further includes a protective film 160, which is disposed between the shielding portion 152 and the pressure relief mechanism 140 and covers the through hole 111 and the pressure relief mechanism 140. In some examples, the protective film 160 is disposed on the surface of the protrusion 111 facing the shielding portion 152 and covers the through hole 111 and the pressure relief mechanism 140. The protective film 160 can seal the through hole 111 and reduce the external dust, water vapor and other impurities that enter the through hole 111. The protective film 160 is a thin film structure with low strength. It is easy to break under the impact of high temperature and high pressure substances and will not affect the discharge of high temperature and high pressure substances. Optionally, the protective film 160 is a transparent PET patch.

[0106] In some embodiments of the present application, the shielding portion 152 presses the protective film 160. The shielding portion 152 and the protrusion 113 clamp the protective film 160 to reduce the risk of the protective film 160 falling off.

[0107] Fig. 9 This is a schematic structural diagram of a protection component 150 according to an embodiment of the present application, which shows the shape of the protection component 150 before being assembled to the cover plate 110; Fig.10 This is a schematic structural diagram of another protective component 150 according to an embodiment of the present application, which shows the shape of the protective component 150 before being assembled to the cover plate 110 .

[0108] Reference Fig. 9 In some embodiments, the shielding portion 152 protruding from the main body 151 is directly formed during the manufacturing process of the protective member 150. The main body 151 and the shielding portion 152 are generally flat and arranged parallel to each other, and the weak portion 153 is generally perpendicular to the main body 151 and the shielding portion 152. The protective member 150 forms a recessed portion on the inner side of the shielding portion 152. When the protective member 150 and the cover plate 110 are assembled, the main body 151 is connected to the cover plate body 114, and the recessed portion of the protective member 150 reserves a receiving space for the protrusion 113 of the cover plate 110.

[0109] Reference Fig.10 In other embodiments, the protective member 150 can be manufactured into a flat plate shape first. At this time, the main body 151, the shielding portion 152 and the weak portion 152 are roughly in the same plane. The molding process of the flat plate-shaped protective member 150 is relatively simple. When assembling the protective member 150 and the cover plate 110, the shielding portion 152 is first placed against the protrusion 113 or the protective film 160, and then the main body 151 is pressed; the weak portion 153 has a relatively small strength, and when the main body 151 is pressed, the weak portion 153 can be deformed, so that the main body 151 is close to the cover plate 110, so that the main body 151 is connected to the cover plate body 114. After the flat plate-shaped protective member 150 is assembled on the cover plate 110, the protrusion 113 can prop up the shielding portion 152, so that the shielding portion 152 protrudes from the main body 151.

[0110] The weak portion 153 can be formed in different ways as needed, as long as the strength of the weak portion 153 can be reduced and the weak portion 153 can be broken when the pressure relief mechanism 140 is actuated.

[0111] Fig.11 for Fig. 9 The protective member 150 is shown in an enlarged view at the circle D. Fig.11 As shown, in some embodiments of the present application, a plurality of through openings 154 are provided between the main body 151 and the shielding portion 152, and the weak portion 153 includes a plurality of sub-weak areas 153a, and the plurality of sub-weak areas 153a and the plurality of openings 154 are alternately provided along the circumference of the shielding portion 152. By providing the openings 154, the protective member 150 can reduce the overall strength of the weak portion 153, and when the high-temperature and high-pressure material impacts the shielding portion 152, the sub-weak areas 153a of the weak portion 153 can be quickly destroyed. In some examples, when the battery cell 10 has thermal runaway, under the impact of the high-temperature and high-pressure material, all the sub-weak areas 153a are destroyed, and the shielding portion 152 is completely freed from the restraint of the main body 151 and is opened by the high-temperature and high-pressure material. In other examples, under the impact of high-temperature and high-pressure materials, only a part of the sub-weak area 153a may be destroyed, and the other part of the sub-weak area 153a still connects the shielding part 152 to the main body 151; at this time, the main body 151 has a smaller binding force on the shielding part 152, and the shielding part 152 may be deformed under the impact of the high-temperature and high-pressure materials, or it may be turned outward with the undamaged sub-weak area 153a as the axis, so that a channel can be formed between the main body 151 and the shielding part 152 for the rapid discharge of the high-temperature and high-pressure materials. When the battery cell 10 is in thermal runaway, the number of sub-weak areas 153a destroyed depends on the capacity of the battery cell 10. Whether all the sub-weak areas 153a are broken or part of the sub-weak areas 153a are broken, as long as the temperature and pressure inside the single battery 10 can be released to a safe range within a certain period of time.

[0112] In some embodiments, there are four sub-weak areas 153 a , two of which are disposed opposite to each other along the length direction of the protective member 150 , and the other two sub-weak areas 153 a are disposed opposite to each other along the width direction of the protective member 150 .

[0113] In some embodiments, in the circumferential direction of the shielding portion 152, the ratio of the size of the connection between the weak portion 153 and the shielding portion 152 to the circumference of the shielding portion 152 is less than 50%; when the shielding portion 152 is impacted by high-temperature and high-pressure materials, the connection between the weak portion 153 and the shielding portion 152 is more likely to break.

[0114] In some embodiments, the thickness of the sub-weak area 153a is less than or equal to the thickness of the main body 151. When the thickness of the sub-weak area 153a is less than the thickness of the main body 151, the strength of the connection between the sub-weak area 153a and the main body 151 is low, and when high-temperature and high-pressure materials impact the protective component 150, the connection between the sub-weak area 153a and the main body 151 is more likely to break.

[0115] In some embodiments, the thickness of the sub-weak area 153a is less than or equal to the thickness of the shielding portion 152. When the thickness of the sub-weak area 153a is less than the thickness of the shielding portion 152, the strength of the connection between the sub-weak area 153a and the shielding portion 152 is low, and when high-temperature and high-pressure materials impact the protective component 150, the connection between the sub-weak area 153a and the shielding portion 152 is more likely to break.

[0116] In some embodiments, the thickness of the sub-weak area 153 a is smaller than the thickness of the main body portion 151 and the thickness of the shielding portion 152 .

[0117] In some examples, the thickness of the main body 151 and the shielding portion 152 are the same. In other examples, the thickness of the shielding portion 152 may also be less than the thickness of the main body 151 .

[0118] In some embodiments, the thicknesses of the main body 151 , the shielding portion 152 , and the sub-weak area 153 a are equal. In this case, the overall thickness of the protection component 150 is uniform, which facilitates molding.

[0119] Fig.12 This is a schematic structural diagram of a protection component 150 according to an embodiment of the present application; Fig.13 for Fig.12 The protective member 150 is shown as a cross-sectional schematic diagram taken along line EE; Fig.14 for Fig.12 Another schematic cross-sectional view of the protection member 150 is shown along line EE. Fig.15 for Fig.12 The protective member 150 is shown as another cross-sectional schematic view taken along line EE.

[0120] In some embodiments, reference Figures 12 to 15 , the protective member 150 is provided with a second groove 154. The position of the second groove 154 can be set according to product requirements. Fig.13 , the second groove 154 is disposed on the inner surface of the protection member 150 (ie, the side surface of the protection member 150 close to the cover plate 110). Fig.14 , the second groove 154 is disposed on the outer surface of the protection member 150 (ie, the side surface of the protection member 150 away from the cover plate 110). Fig.15The second groove 154 is provided on both the inner surface and the outer surface of the protection member 150 .

[0121] Reference Figures 12 to 15 The weak portion 153 is the bottom wall of the second groove 154. By providing the second groove 154, the thickness of the weak portion 153 can be reduced, that is, the strength of the weak portion 153 can be reduced, and the weak portion 153 can be quickly broken when impacted by high-temperature and high-pressure materials.

[0122] In some embodiments, the second groove 154 is an annular groove surrounding the shielding portion 152. Correspondingly, the weak portion 153 is annular and is arranged around the edge of the shielding portion 152. When the shielding portion 152 is impacted by a high-temperature and high-pressure substance, each part of the weak portion 153 can be broken, which can increase the discharge rate of the high-temperature and high-pressure substance.

[0123] In some examples, there is one annular second groove 154. Optionally, there may be multiple annular second grooves 154, which are arranged at intervals along the direction from the main body 151 to the shielding portion 152. The number of second grooves 154 can be set according to the capacity of the battery cell 10, as long as the temperature and pressure inside the single battery 10 can be released to a safe range within a certain period of time.

[0124] In some embodiments, the second grooves 154 are a plurality of strip-shaped grooves, and the plurality of second grooves 154 are arranged at intervals along the circumference of the shielding portion 152 .

[0125] The smaller the thickness of the weak portion 153, the lower the strength of the weak portion 153; if the thickness of the weak portion 153 is too small, when the battery cell vibrates, the weak portion 153 is easy to break, causing the protection member 150 to fail. On the contrary, the larger the thickness of the weak portion 153, the higher the strength of the weak portion 153; if the thickness of the weak portion 153 is too large, then when the high-temperature and high-pressure material impacts the shielding portion 152, the time required for the weak portion 153 to break is too long, affecting the discharge of the high-temperature and high-pressure material. Therefore, in some embodiments, the thickness of the weak portion 153 is 0.08mm to 0.3mm.

[0126] In some embodiments, the thickness of the main body 151 may be equal to the thickness of the shielding portion 152. In other embodiments, the thickness of the shielding portion 152 may also be less than the thickness of the main body 151.

[0127] like Fig.15 As shown, the protection member 150 includes an inner second groove 154 and an outer second groove 154 , and along the thickness direction of the weak portion 153 , the inner second groove 154 and the outer second groove 154 at least partially overlap, which can reduce the minimum thickness of the weak portion 153 .

[0128] Fig.16 FIG. 1 is a schematic diagram showing a process of manufacturing a battery cell according to an embodiment of the present application. Fig.16 As shown, the manufacturing method may include:

[0129] S210: providing an end cap assembly 100, the end cap assembly 100 comprising a cover plate 110, an electrode terminal and a pressure relief mechanism 140, wherein the pressure relief mechanism 140 and the electrode terminal are disposed on the cover plate 110, and the pressure relief mechanism 140 is used to actuate to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold value;

[0130] S220: providing an electrode assembly 101, and connecting the electrode assembly 101 to an electrode terminal;

[0131] S230: providing a housing 102, wherein the housing 102 has a receiving cavity and an opening;

[0132] S240: placing the electrode assembly 101 connected to the electrode terminal into the accommodation cavity, and then connecting the cover plate 110 to the housing 102 to close the opening of the housing 102;

[0133] S250: Provide a protective member 150, which includes a main body 151, a shielding portion 152 and a weak portion 153, wherein the weak portion 153 is used to connect the main body 151 and the shielding portion 152, and the weak portion 153 is configured to rupture when the pressure relief mechanism 140 is actuated to disconnect the main body 151 and the shielding portion 152.

[0134] S260 : The protection component 150 is disposed on the outer side of the cover plate 110 , and the main body 151 is connected to the cover plate 110 , and the shielding portion 152 shields the pressure relief mechanism 140 .

[0135] The relevant structure of the battery cell manufactured by the manufacturing method of this embodiment can refer to the aforementioned Figure 1-Figure 15 The relevant contents described in the corresponding embodiments will not be repeated here.

[0136] Fig.17 FIG. 1 is a schematic diagram showing a structure of a battery cell manufacturing system according to an embodiment of the present application. Fig.17 As shown, the battery cell manufacturing system 300 of the embodiment of the present application may include a first providing device 310 , a second providing device 320 , a third providing device 330 , a fourth providing device 340 , a first assembling device 350 , a second assembling device 360 ​​and a third assembling device 370 .

[0137] The first providing device 310 is used to provide an end cap assembly 100, which includes a cover plate 110, an electrode terminal and a pressure relief mechanism 140, wherein the pressure relief mechanism 140 and the electrode terminal are arranged on the cover plate 110, and the pressure relief mechanism 140 is used to actuate to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold.

[0138] The second providing device 320 is used to provide the electrode assembly 101. The first assembling device 350 is used to connect the electrode assembly 101 to the electrode terminal. The third providing device 330 is used to provide a shell 102, and the shell 102 has a accommodating cavity and an opening. The second assembling device 360 ​​is used to place the electrode assembly 101 connected to the electrode terminal into the accommodating cavity, and connect the cover plate 110 to the shell 102 to close the opening of the shell 102. The fourth providing device 340 is used to provide a protective member 150, and the protective member 150 includes a main body 151, a shielding portion 152 and a weak portion 153, and the weak portion 153 is used to connect the main body 151 and the shielding portion 152, and the weak portion 153 is configured to rupture when the pressure relief mechanism 140 is actuated to disconnect the main body 151 and the shielding portion 152. The third assembling device 370 is used to dispose the protection component 150 on the outer side of the cover plate 110 , and connect the main body 151 to the cover plate 110 and the shielding portion 152 to shield the pressure relief mechanism 140 .

[0139] The relevant structure of the battery cell manufactured by the manufacturing system of this embodiment can refer to the aforementioned Figure 1-Figure 15 The relevant contents described in the corresponding embodiments will not be repeated here.

[0140] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein, but these modifications or replacements 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 the present application.

Claims

1. A battery cell, characterized in that: include: A battery box, comprising a first wall and a pressure relief mechanism, wherein the pressure relief mechanism is arranged on the first wall and is provided with a first groove, and the pressure relief mechanism is used to rupture at the first groove to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold value; A protective component is located on the outer side of the first wall, the protective component includes a main body, a shielding portion and a weak portion, the main body is used to connect the first wall, the shielding portion is used to shield the pressure relief mechanism, the shielding portion completely covers the first groove, a plurality of through openings are arranged between the main body and the shielding portion, the weak portion includes a plurality of sub-weak areas, a plurality of the sub-weak areas and a plurality of the openings are alternately arranged along the circumference of the shielding portion, the sub-weak areas are used to connect the main body and the shielding portion, and the weak portion is configured to at least partially rupture the plurality of sub-weak areas when the pressure relief mechanism is actuated to disconnect the main body and the shielding portion.

2. The battery cell according to claim 1, characterized in that: The battery cell further includes an adhesive member, and the protection member is connected to the first wall through the adhesive member.

3. The battery cell according to claim 2, characterized in that: The surface of the main body facing the first wall is provided with the adhesive component, while the surface of the shielding portion facing the first wall and the surface of the weak portion facing the first wall are not provided with the adhesive component.

4. The battery cell according to claim 1, characterized in that: The melting point of the protection component is greater than the melting point of the pressure relief mechanism.

5. The battery cell according to claim 1, characterized in that: The melting point of the protective member is not less than 600 degrees.

6. The battery cell according to claim 1, characterized in that: The material of the protection component includes at least one of mica, rubber and ceramics.

7. The battery cell according to claim 1, characterized in that: The thickness of the shielding portion is smaller than the thickness of the main body portion.

8. The battery cell according to claim 1, characterized in that: The shielding portion protrudes outward from the main body along a direction perpendicular to the first wall.

9. The battery cell according to claim 8, characterized in that: A protrusion is provided on the outer surface of the first wall, and along a direction perpendicular to the first wall, the shielding portion is located on a side of the protrusion away from the pressure relief mechanism.

10. The battery cell according to claim 9, characterized in that: The battery cell further includes a protective film, which is disposed on a surface of the protrusion facing the shielding portion and covers the pressure relief mechanism.

11. The battery cell according to claim 10, characterized in that: The shielding portion presses the protective film.

12. The battery cell according to claim 1, characterized in that: The thickness of the sub-weak area is less than or equal to the thickness of the main body; and / or the thickness of the sub-weak area is less than or equal to the thickness of the shielding portion.

13. The battery cell according to claim 1, characterized in that: A second groove is provided on a surface of the protection member on one side away from the first wall, and the weak portion is a bottom wall of the second groove; and / or A second groove is provided on a side surface of the protection component close to the first wall, and the weak portion is a bottom wall of the second groove.

14. The battery cell according to claim 13, characterized in that: The second groove is an annular groove surrounding the shielding portion.

15. The battery cell according to claim 13 or 14, characterized in that: The thickness of the weak portion is 0.08 mm to 0.3 mm.

16. The battery cell according to claim 1, characterized in that: The battery box comprises: A housing having a receiving cavity and an opening; The end cover assembly comprises a cover plate and an electrode terminal, wherein the cover plate covers the opening of the shell, the electrode terminal is arranged on the cover plate, and the first wall is the cover plate.

17. The battery cell according to claim 16, characterized in that: The battery cell further includes an electrode assembly, and the electrode assembly is accommodated in the accommodation cavity.

18. A battery, characterized in that: The invention comprises a box body and at least one battery cell according to any one of claims 1 to 17, wherein the battery cell is accommodated in the box body.

19. An electrical device, characterized in that: The electric device is configured to receive electric energy provided from the battery according to claim 18.

20. A method for manufacturing a battery cell, characterized in that: include: An end cap assembly is provided, the end cap assembly comprising a cover plate, an electrode terminal and a pressure relief mechanism, the pressure relief mechanism and the electrode terminal are arranged on the cover plate, the pressure relief mechanism is provided with a first groove, and the pressure relief mechanism is used to rupture at the first groove to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold value; Providing an electrode assembly, and connecting the electrode assembly to the electrode terminal; Providing a housing, wherein the housing has a receiving cavity and an opening; placing the electrode assembly connected to the electrode terminal into the accommodation cavity, and then connecting the cover plate to the housing to close the opening of the housing; A protection component is provided, the protection component comprising a main body, a shielding portion and a weak portion, a plurality of through openings are arranged between the main body and the shielding portion, the weak portion comprises a plurality of sub-weak areas, the plurality of sub-weak areas and the plurality of openings are alternately arranged along the circumference of the shielding portion, the sub-weak areas are used to connect the main body and the shielding portion, and the weak portion is configured such that when the pressure relief mechanism is actuated, at least a portion of the plurality of sub-weak areas is ruptured to disconnect the main body and the shielding portion; The protection component is arranged on the outer side of the cover plate, and the main body is connected to the cover plate, and the shielding part shields the pressure relief mechanism and completely covers the first groove.

21. A battery cell manufacturing system, characterized in that: include: A first providing device is used to provide an end cap assembly, the end cap assembly comprising a cover plate, an electrode terminal and a pressure relief mechanism, the pressure relief mechanism and the electrode terminal are arranged on the cover plate, the pressure relief mechanism is provided with a first groove, and the pressure relief mechanism is used to rupture at the first groove to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold value; A second providing device, for providing an electrode assembly; a first assembling device, used to connect the electrode assembly to the electrode terminal; A third providing device is used to provide a housing, wherein the housing has a receiving cavity and an opening; a second assembling device, for placing the electrode assembly connected to the electrode terminal into the accommodation cavity, and connecting the cover plate to the housing to close the opening of the housing; A fourth providing device is used to provide a protective member, the protective member comprising a main body, a shielding portion and a weak portion, a plurality of through openings are arranged between the main body and the shielding portion, the weak portion comprises a plurality of sub-weak areas, the plurality of sub-weak areas and the plurality of openings are alternately arranged along the circumference of the shielding portion, the sub-weak areas are used to connect the main body and the shielding portion, and the weak portion is configured such that when the pressure relief mechanism is actuated, at least part of the plurality of sub-weak areas is ruptured to disconnect the main body and the shielding portion; The third assembly device is used to arrange the protection component on the outer side of the cover plate, connect the main body to the cover plate, and shield the pressure relief mechanism and completely cover the first groove.

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