Battery cell and method for producing a battery cell

Abstract

This application provides a battery cell and a method for manufacturing the battery cell. The battery cell includes a pressure relief mechanism and a protective film disposed on the outside of the pressure relief mechanism. A protective member is used to cover at least a portion of the protective film from the outside. The protective member has vent holes that penetrate the protective member along its thickness direction; the vent holes are used to connect the space outside the protective member and the space between the protective film and the pressure relief mechanism when the protective member is connected to the battery cell. In the embodiments of this application, the protective member is disposed on the outside of the protective film. The placement of the protective member can reduce the risk of damage and deformation of the protective film during the battery cell manufacturing process, thereby reducing the probability of damage to the pressure relief mechanism or contamination by the electrolyte. This allows the pressure relief mechanism to be actuated when the internal pressure of the battery cell reaches a predetermined threshold, ensuring the normal operation of the pressure relief mechanism and improving the safety of the battery cell.

Description

[0001] This application is a divisional application based on the invention with application number 202211587841.8, application date December 12, 2022, applicant CATL, and invention title "Preparation method of protective component and battery cell". Technical Field

[0002] This application relates to the field of battery technology, and in particular to a battery cell and a method for preparing the battery cell. Background Technology

[0003] 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.

[0004] In the development of battery technology, improving the safety of individual battery cells is an important research direction. Summary of the Invention

[0005] In view of the above problems, this application provides a battery cell and a method for preparing the battery cell, which can improve battery safety.

[0006] This application provides a protective member for connection to a battery cell. The battery cell includes a pressure relief mechanism and a protective film disposed outside the pressure relief mechanism. The protective member is used to cover at least a portion of the protective film from the outside.

[0007] In the above scheme, the protective component is set on the outside of the protective film. The setting of the protective component can reduce the risk of damage and deformation of the protective film during the battery cell manufacturing process, thereby reducing the probability of damage to the pressure relief mechanism or contamination by electrolyte. This allows the pressure relief mechanism to be actuated when the internal pressure of the battery cell reaches a predetermined threshold, ensuring the normal operation of the pressure relief mechanism and improving the safety of battery cell use.

[0008] In some embodiments, the protective member is provided with vent holes that penetrate the protective member along its thickness direction. The vent holes are used to connect the space outside the protective member and the space between the protective film and the pressure relief mechanism when the protective member is connected to the battery cell.

[0009] In the above solution, the vent hole can connect the space between the protective membrane and the pressure relief mechanism with the space outside the protective component, thereby reducing the risk of damage and deformation of the protective membrane while meeting the leakage detection requirements of the pressure relief mechanism, which has strong practicality.

[0010] In some embodiments, the protective film is provided with an exhaust channel communicating with the space between the protective film and the pressure relief mechanism. Vent holes are used to connect the exhaust channel when the protective component is connected to the battery cell.

[0011] In the above solution, the vent is connected to the exhaust channel, thereby achieving spatial connection between the protective membrane and the pressure relief mechanism, meeting the leakage detection requirements of the pressure relief mechanism, and has strong practicality.

[0012] In some embodiments, the vent is configured such that when the protective member is connected to the battery cell, the projection of the vent along the thickness direction at least partially overlaps with the projection of the exhaust channel along the thickness direction.

[0013] The above solution improves the conductivity between the vent and the exhaust channel, ensuring efficient air exchange between the air outside the protective component and the space between the protective membrane and the pressure relief mechanism. This balances air pressure and reduces the risk of the protective membrane detaching or wrinkling. Furthermore, during leak detection of the pressure relief mechanism, this design ensures that specific gases are effectively injected into the corresponding location of the mechanism, guaranteeing subsequent effective detection of gas concentration near the mechanism and improving the accuracy of leak detection.

[0014] In some embodiments, the protective member is provided with a plurality of vent holes.

[0015] In the above solution, the presence of multiple vents can improve the conductivity between the space between the protective membrane and the pressure relief mechanism and the atmosphere, reduce the risk of the protective membrane falling off or wrinkling and deforming, and at the same time improve the accuracy of the air leakage detection of the pressure relief mechanism.

[0016] In some embodiments, the plurality of vent holes are rotationally symmetrical about the central axis of the protective member.

[0017] In the above scheme, since multiple vent holes are rotationally symmetrical about the central axis, when the protective component is connected with the battery cell at a certain angle, the other vent holes can correspond to the exhaust channel, thus meeting the requirements for gas communication or leakage detection. This reduces the probability of vent hole failure due to relative deflection or misalignment between the protective component and the battery cell, thereby reducing the required connection accuracy between the protective component and the battery cell.

[0018] In some embodiments, the plurality of vent holes are centrally symmetrical about the central axis of the protective member.

[0019] In the above solution, by making multiple vent holes symmetrical about the central axis of the protective component, even when the protective component is attached upside down, some vent holes can still communicate with the exhaust channel, thus meeting the needs of gas conduction and leakage detection. The protective component provided in this application embodiment has strong adaptability and versatility and can be applied to various situations.

[0020] In some embodiments, the protective member includes a base layer and an adhesive layer disposed on the surface of the base layer.

[0021] In the above scheme, a bonding layer is used to achieve a fixed connection between the base layer and the battery cell, resulting in a simple and reliable structure. During battery cell movement or transportation, the possibility of the protective component detaching from the battery cell is reduced. This allows the protective component to provide long-term protection for the protective film during battery cell fabrication, improving battery yield.

[0022] In some embodiments, the protective film is attached to the outer casing of the battery cell, and the protective member is configured such that when the protective member is attached to the battery cell, the connection strength between the protective member and the protective film is less than the connection strength between the protective film and the outer casing.

[0023] In the above scheme, the connection strength between the protective component and the protective film is set to be less than the connection strength between the protective film and the outer shell. Therefore, during the separation process of the protective component and the battery cell, since the force between the protective component and the protective film is less than the force between the protective film and the outer shell, the protective component cannot separate the protective film from the outer shell, ensuring that the protective film can cover the pressure relief mechanism and play a protective role for the pressure relief mechanism.

[0024] In some embodiments, the protective member is configured such that, when the protective member is connected to a battery cell, the connection strength between the protective member and the protective film is less than the connection strength between the protective member and the casing.

[0025] In the above scheme, during the separation process of the protective component from the battery cell, the protective component can be separated from the protective film first, thereby reducing the probability of the protective film being displaced relative to the outer shell due to the movement of the protective component, and ensuring that the protective film can cover the pressure relief mechanism to protect the pressure relief mechanism.

[0026] In some embodiments, the protective film is attached to the first wall of the battery cell, the protective member includes a main body and an extension protruding from the main body, a vent is provided in the main body, and the protective member is configured such that when the protective member is attached to the first wall, the extension can protrude relative to the first wall.

[0027] In the above solution, by providing an extension that protrudes relative to the first wall, when it is necessary to separate the protective component from the battery cell, the extension can be pulled to apply external force to the protective component, thereby separating it from the battery cell. This reduces the risk that the protective component cannot be directly separated from the battery cell due to an overly tight connection between the main body and the battery cell.

[0028] In some embodiments, when the protective member is connected to the battery cell, at least a portion of the structure in the extension is suspended.

[0029] In the above solution, by suspending at least part of the extension, when it is necessary to separate the protective member from the battery cell, the extension can be easily grasped and a certain external force can be applied to the extension to separate the protective member from the battery cell. This design can better apply external force to the extension, thereby further reducing the difficulty of separating the protective member from the battery cell.

[0030] In some embodiments, the number of extensions is multiple, and the multiple extensions are respectively disposed on two opposite edges of the main body.

[0031] In the above solution, the extension is used to help separate the protective component from the battery cell. Based on this, the embodiments of this application set multiple extensions so that when some of the extensions fail, the separation between the protective component and the battery cell can still be achieved through other extensions.

[0032] Furthermore, multiple extensions are located on two opposite edges of the main body. In this case, the extensions can also play a positioning role to a certain extent. By using multiple extensions arranged opposite to each other, the relative positional relationship between the protective component and the battery cell is determined, improving the accuracy of their positions, so that the protective component can better protect the pressure relief mechanism and the protective film.

[0033] In some embodiments, the protrusion distance of the extension relative to the first wall is D, where D satisfies: 8mm≤D≤10mm.

[0034] In the above scheme, the protrusion distance D of the extension relative to the first wall is set between 8mm and 10mm, so as to reduce the risk of the protective component detaching from the battery cell due to external factors while ensuring that the protective component can be easily separated from the battery cell.

[0035] Secondly, embodiments of this application provide a method for preparing a battery cell, the battery cell including a pressure relief mechanism and a protective film disposed on the outside of the pressure relief mechanism, the preparation method including:

[0036] The protective component is connected to the battery cell and covers at least a portion of the protective film from the outside;

[0037] Inject electrolyte into individual battery cells;

[0038] Separate the protective components from the battery cells.

[0039] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0040] 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 these drawings without creative effort.

[0041] Figure 1 This is an exploded schematic diagram of a single battery cell provided in an embodiment of this application;

[0042] Figure 2 This is a structural schematic diagram of a protective component provided in an embodiment of this application;

[0043] Figure 3 This is a schematic diagram of the cooperation structure between a protective component and a battery cell provided in an embodiment of this application;

[0044] Figure 4 This is a schematic diagram of the structure of a protective film in a battery cell provided in an embodiment of this application;

[0045] Figure 5 This is a schematic diagram of a protective film structure in a battery cell provided in an embodiment of this application;

[0046] Figure 6 This is a schematic diagram of another protective component provided in an embodiment of this application;

[0047] Figure 7 This is a schematic diagram of another protective component provided in an embodiment of this application;

[0048] Figure 8 yes Figure 6 Schematic diagram of the cross-sectional structure at point AA;

[0049] Figure 9 This is a flowchart of a method for preparing a battery cell provided in an embodiment of this application.

[0050] In the attached image:

[0051] 10. Battery cell; 11. Casing; 111. Housing; 112. End cap; 12. Electrode assembly; 13. Electrode terminal; 14. Current collector; 15. Pressure relief mechanism; 16. Protective film;

[0052] 20. Protective components; 21. Ventilation holes; 22. Base layer; 23. Adhesive layer; 24. Main body; 25. Extension;

[0053] 30. Through hole;

[0054] T, exhaust passage;

[0055] A. Breathable area;

[0056] O, central axis;

[0057] B. First wall;

[0058] X, first direction; Y, second direction; Z, thickness direction. Detailed Implementation

[0059] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein 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 specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0061] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0062] In this document, the term "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 throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0063] In the description of the embodiments 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, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0064] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0065] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0066] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0067] 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.

[0068] 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.

[0069] In this application, "multiple" refers to two or more (including two). In this application, a 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 this application does not limit the specific type. A battery cell may be cylindrical, flat, cuboid, or other shapes, and this application does not limit the specific shape either. Battery cells are generally classified into three types according to their packaging method: cylindrical battery cells, square battery cells, and pouch battery cells, and this application does not limit the specific type either.

[0070] 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 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.

[0071] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly consists of 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. The positive active material layer is coated on the surface of the positive current collector, and the uncoated positive current collector protrudes beyond the coated one, serving as the positive electrode tab. Taking a lithium-ion battery as an example, the positive current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector, and the uncoated negative current collector protrudes beyond the coated one, serving as the negative electrode tab. The negative electrode current collector can be made of copper, and the negative electrode active material can be carbon or silicon, etc. To ensure that a large current can be passed without melting, there are multiple positive electrode tabs stacked together, and there are multiple negative electrode tabs stacked together. The diaphragm can be made of polypropylene (PP) or polyethylene (PE), etc. In addition, the electrode assembly can be a wound structure or a stacked structure, and the embodiments of this application are not limited to these.

[0072] The battery cell also includes a housing for housing the electrode assembly and electrolyte. The housing includes a casing and end caps connected to the casing, which together form a cavity for housing the electrode assembly and electrolyte.

[0073] 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.

[0074] 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.

[0075] A pressure relief mechanism is a component or part that is activated to release internal pressure or temperature when the internal pressure or temperature 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. The internal pressure of the battery cell is the same as the pressure inside the casing.

[0076] 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 employ a pressure-sensitive element or structure. That is, when the internal pressure of a battery cell reaches a predetermined threshold, the pressure relief mechanism actuates or a weak part in the pressure relief mechanism ruptures, thereby forming an opening or channel for releasing internal pressure. The weak part can be formed by setting grooves, indentations, or using materials with low strength.

[0077] 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.

[0078] 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.

[0079] The inventors noted that during the cycling process of a battery cell, the pressure relief mechanism may activate prematurely or fail before the internal pressure of the battery cell reaches a threshold. Based on this problem, the inventors discovered that a protective film is installed on the outside of the pressure relief mechanism to protect it. However, during the battery cell manufacturing process, this protective film is easily scratched and bumped, leading to deformation, warping, or even detachment. Furthermore, during electrolyte injection, residual electrolyte on the processing table or electrolyte that falls onto the casing during injection can easily adhere to the protective film, affecting its appearance. It may also penetrate along the edge of the protective film to the pressure relief mechanism, contacting it and causing corrosion that affects its activation threshold. This can result in premature activation or failure before the internal pressure of the battery cell reaches the predetermined threshold, impacting normal battery use and posing safety hazards.

[0080] Based on the problems discovered by the inventors, this application provides a protective component that reduces the risk of damage and deformation of the protective film, thereby reducing the impact of the manufacturing process on the pressure relief mechanism.

[0081] Please see Figure 1 , Figure 1 This application provides an exploded view of a single battery cell 10. (See attached diagram.) Figure 1 As shown, the battery cell 10 includes a housing 11 and an electrode assembly 12, with the electrode assembly 12 housed within the housing 11.

[0082] The electrode assembly 12 is the core component for enabling the charging and discharging function of the battery cell 10. 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 12 mainly relies on the movement of metal ions between the positive and negative electrodes to operate.

[0083] The outer shell 11 is a hollow structure, with an internal cavity for accommodating the electrode assembly 12 and the electrolyte. The outer shell 11 can be of various shapes, such as a cylinder or a cuboid. The shape of the outer shell 11 can be determined according to the specific shape of the electrode assembly 12. For example, if the electrode assembly 12 is a cylindrical structure, a cylindrical outer shell 11 can be used; if the electrode assembly 12 is a cuboid structure, a cuboid outer shell 11 can be used.

[0084] In some embodiments, the housing 11 includes a housing 111 and end caps 112. The end caps 112 are hermetically connected to the housing 111 to form a sealed space for accommodating the electrode assembly 12 and the electrolyte. In some examples, one end of the housing 111 has an opening, and the end cap 112 is configured as one that covers the opening of the housing 111. In other examples, both opposite ends of the housing 111 have openings, and two end caps 112 are configured, each covering one of the two openings of the housing 111.

[0085] Regardless of the specific type, the shape of the end cap 112 can be adapted to the shape of the housing 111 to fit the housing 111. Optionally, the end cap 112 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 112 is not easily deformed when subjected to compression and impact, so that the battery cell 10 can have higher structural strength and the safety performance can also be improved.

[0086] The housing 111 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 111 can be determined according to the specific shape and size of the electrode assembly 12. The material of the housing 111 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and this application embodiment does not impose any special limitations on this.

[0087] In some embodiments, the end cap 112 may be provided with functional components such as electrode terminals 13. The electrode terminals 13 can be used to electrically connect with the electrode assembly 12 for outputting or inputting electrical energy of the battery cell 10. Optionally, the housing 11 is further provided with a current collector 14, which is used to realize the electrical connection between the electrode assembly 12 and the electrode terminals 13.

[0088] In some embodiments, the housing 11 is provided with a pressure relief mechanism 15. When the electrode assembly 12 experiences thermal runaway, the high-temperature gas generated inside the housing 111 can reach the pressure relief mechanism 15. The pressure relief mechanism 15 is pushed open by the impact force, allowing the high-temperature gas to be released in time, ensuring the continued use of the battery cell 10. It should be noted that the pressure relief mechanism 15 can be provided on the end cap 112 or on the housing 111; this embodiment does not limit this.

[0089] Furthermore, in some embodiments, a protective film 16 is provided on the outside of the pressure relief mechanism 15, which can protect the pressure relief mechanism 15.

[0090] In order to reduce the possibility that the pressure relief mechanism 15 may malfunction due to damage or deformation of the protective film 16 caused by external factors during the preparation of the battery cell 10, this application provides a protective component 20. The structure of the protective component 20 will be described in detail below with reference to the accompanying drawings.

[0091] Please see Figures 1 to 3 The protective member 20 is used to connect to the battery cell 10, which includes a pressure relief mechanism 15 and a protective film 16 disposed outside the pressure relief mechanism 15. The protective member 20 is used to cover at least a portion of the protective film 16 from the outside.

[0092] The pressure relief mechanism 15 on the battery cell 10 has a significant impact on the safety of the battery cell 10. For example, when a short circuit or overcharging occurs, thermal runaway may occur inside the battery cell 10, causing a sudden increase in pressure. In this case, the pressure relief mechanism 15 can be activated to release the internal pressure to the outside, preventing the battery cell 10 from exploding or catching fire.

[0093] The pressure relief mechanism 15 is a component or part that is actuated to release internal pressure or temperature when the internal pressure or temperature of the battery cell 10 reaches a predetermined threshold. This threshold design varies depending on design requirements. It may depend on one or more materials of the positive electrode, negative electrode, electrolyte, and separator in the battery cell 10. The internal pressure of the battery cell 10 is the same as the pressure inside the casing 11.

[0094] The pressure relief mechanism 15 can take the form of an explosion-proof valve, a gas valve, a pressure relief valve, or a safety valve, and can specifically employ a pressure-sensitive element or structure. That is, when the internal pressure of the battery cell 10 reaches a predetermined threshold, the pressure relief mechanism 15 actuates or a weak part provided in the pressure relief mechanism 15 ruptures, thereby forming an opening or channel for releasing internal pressure. The weak part can be formed by setting grooves, indentations, or using materials with low strength.

[0095] The term "actuation" as used in this application refers to the pressure relief mechanism 15 being activated or undergoing a certain state, thereby releasing the internal pressure of the battery cell 10. The action of the pressure relief mechanism 15 may include, but is not limited to, at least a portion of the pressure relief mechanism 15 rupturing, breaking, tearing, or opening, etc. When the pressure relief mechanism 15 is actuated, the high-temperature, high-pressure substances inside the battery cell 10 are discharged outwards from the actuated portion as waste. This method allows for pressure relief of the battery cell 10 under controllable pressure, thereby preventing potentially more serious accidents.

[0096] The emissions from the battery cell 10 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.

[0097] The protective film 16 is used to protect the pressure relief mechanism 15. Specifically, the protective film 16 can prevent sharp objects from damaging the pressure relief mechanism 15, prevent electrolytes and other liquids from contaminating and corroding the pressure relief mechanism 15, or prevent foreign objects, dust, etc. from falling into the pressure relief mechanism 15 and affecting the appearance of the battery cell 10. For example, the protective film 16 can be a PET film (Polyethylene terephthalate), also known as a high-temperature resistant polyester film. Using PET film to make the protective film 16 can improve the plasticity, tensile strength, and impact resistance of the protective film 16, so that the structure of the protective film 16 is stable and the risk of deformation after long-term use is reduced.

[0098] The protective member 20 can cover at least a portion of the protective film 16 from the outside. Here, "outside" refers to the outer side of the entire battery cell 10, and for the protective film 16, it is the side of the protective film 16 facing away from the pressure relief mechanism 15. The protective member 20 can cover at least a portion of the protective film 16, meaning that the orthographic projection of the protective member 20 on the protective film 16 overlaps with the protective film 16. The orthographic projection of the protective member 20 on the protective film 16 may only overlap with at least a portion of the protective film 16, or it may completely cover the protective film 16.

[0099] The protective component 20 is connected to the battery cell 10, and the connection method includes, but is not limited to, adhesive bonding. The protective component 20 can be directly connected to the protective film 16, or the protective component 20 can be connected to other structures in the battery cell 10 other than the protective film 16.

[0100] The protective member 20 has various structural dimensions. The outline shape of the protective member 20 can be the same as or different from the outline shape of the protective film 16. The thickness of the protective member 20 can be greater than, less than, or equal to, the thickness of the protective film 16. For example, the thickness of the protective member 20 can be greater than the thickness of the protective film 16, thereby enabling the protective member 20 to better protect the protective film 16 during the manufacturing process of the battery cell 10, reducing the risk of damage or deformation of the protective film 16 due to external factors.

[0101] Furthermore, the protective component 20 can also be made of various materials, including the same material as the protective film 16 or a different material. For example, the protective component 20 may include a corrosion-resistant material, which can reduce the impact of the electrolyte on the protective component 20 and decrease the probability of protective failure. The protective component 20 may also include a material with high structural strength, referring to the material's ability to resist external forces. The higher the structural strength, the greater the maximum external force the protective component 20 can withstand, thus reducing the impact of external forces on the protective film 16 and lowering the risk of deformation, warping, or even detachment of the protective film 16 due to scratches or impacts.

[0102] The protective component 20 provided in this embodiment is applicable during the preparation or transportation of the battery cell 10, and can better protect the protective film 16 and the pressure relief mechanism 15. It should be noted that, depending on the actual use, the protective component 20 provided in this embodiment can also be applied to other scenarios, and this embodiment does not limit this application. For example, during the use of the battery cell 10, the protective component 20 may or may not be provided on the battery cell 10.

[0103] In this embodiment, the protective member 20 is disposed on the outside of the protective film 16. The protective member 20 can reduce the risk of damage and deformation of the protective film 16 during the preparation of the battery cell 10, thereby reducing the probability of damage to the pressure relief mechanism 15 or contamination by the electrolyte. This allows the pressure relief mechanism 15 to be actuated when the internal pressure of the battery cell 10 reaches a predetermined threshold, ensuring the normal operation of the pressure relief mechanism 15 and improving the safety of the battery cell 10.

[0104] In some embodiments, such as Figures 1 to 3 As shown, the protective member 20 is provided with a vent 21, which penetrates the protective member 20 along the thickness direction Z. The vent 21 is used to connect the space outside the protective member 20 and the space between the protective film 16 and the pressure relief mechanism 15 when the protective member 20 is connected to the battery cell 10.

[0105] During the fabrication of the battery cell 10, it is typically necessary to detect any leakage in the pressure relief mechanism 15 within the battery cell 10 using methods such as gas detection. Specifically, during gas detection, the air near the pressure relief mechanism 15 is evacuated, and a specific gas, such as helium, is introduced at a certain pressure. Then, the specific gas near the pressure relief mechanism 15 is evacuated again, or the battery cell 10 is transferred to another workstation. After a period of settling, the concentration of the specific gas around the pressure relief mechanism 15 is measured using an instrument. If the detected concentration is lower than a preset value, it indicates that there is no leakage in the pressure relief mechanism 15; if the detected concentration is higher than the preset value, it indicates that there is a leakage problem at the location of the pressure relief mechanism 15.

[0106] A protective film 16 covers the pressure relief mechanism 15 to ensure the effective operation of the gas detection process. Typically, the protective film 16 and the pressure relief mechanism 15 are spaced apart. If there is a leak in the pressure relief mechanism 15, this space can be used to connect to the inside of the battery cell 10 through the leak. Therefore, the space between the protective film 16 and the pressure relief mechanism 15 allows for leak detection of the pressure relief mechanism 15.

[0107] Based on this, the embodiments of this application provide a vent hole 21 on the protective member 20, and the vent hole 21 penetrates the protective member 20 along the thickness direction Z. The number of vent holes 21 can be one or more. The embodiments of this application do not limit the shape and size of the vent hole 21. Exemplarily, the vent hole 21 can be a circular hole, a polygonal hole, or other irregularly shaped through-hole structure, or the vent hole 21 can also be a narrow slit structure. Alternatively, in some embodiments, the vent hole 21 is a notch structure located at the edge of the protective member 20, in other words, the vent hole can be formed by an inward recess from the edge of the protective member 20.

[0108] Furthermore, the position of the vent 21 relative to the protective film 16 can be varied. For example, the projection of the vent 21 onto the thickness direction Z can overlap with the projection of the protective film 16 onto the thickness direction Z, or it can be misaligned with the projection of the protective film 16 onto the thickness direction Z. The "projection of the vent 21 onto the thickness direction Z" mentioned in this embodiment refers to the orthographic projection of the vent 21 onto a plane perpendicular to the thickness direction Z. The projection of the protective film 16 onto the thickness direction Z is similar and will not be described further in this embodiment.

[0109] The space between the protective film 16 and the pressure relief mechanism 15 can communicate with the vent 21. Furthermore, the presence of the vent 21 can enable the space between the protective film 16 and the pressure relief mechanism 15 to communicate with the space outside the protective member 20. The "space outside the protective member 20" mentioned here refers to the space on the side of the protective member 20 away from the battery cell 10 after the protective member 20 is connected to the battery cell 10.

[0110] In this embodiment, the vent 21 can connect the space between the protective film 16 and the pressure relief mechanism 15 with the space outside the protective member 20, thereby reducing the risk of damage and deformation of the protective film 16 while meeting the leakage detection requirements of the pressure relief mechanism 15, which has strong practicality.

[0111] In some embodiments, please refer to Figure 1 , Figure 2 as well as Figure 4 The protective membrane 16 is provided with an exhaust channel T, which connects the protective membrane 16 and the pressure relief mechanism 15. The vent 21 is used to connect the exhaust channel T when the protective member 20 is connected to the battery cell 10.

[0112] The exhaust passage T allows gas to pass through, and the exhaust passage T can take various forms. Exemplarily, in the direction from the pressure relief mechanism 15 towards the protective membrane 16, the exhaust passage T penetrates the protective structure. In this case, as... Figure 5As shown, the exhaust channel T can be a through-hole structure, and its shape includes, but is not limited to, circular holes, triangular holes, and square holes. Alternatively, a portion of the edge of the protective film 16 is connected to the outer casing 11 of the battery cell 10, while at other edge positions, the surface of the protective film 16 facing the pressure relief mechanism 15 is recessed away from the pressure relief mechanism 15 to form a recess. The recess is not connected to the outer casing 11 and is spaced apart from the outer casing 11, thereby forming a recess as shown in the figure. Figure 4 The exhaust passage T is shown.

[0113] The exhaust channel T connects the space between the protective film 16 and the pressure relief mechanism 15 to other spaces to meet the leakage detection requirements of the pressure relief mechanism 15. It also ensures that the space between the protective film 16 and the pressure relief mechanism 15 is connected to the atmosphere, thereby balancing the air pressure and reducing the risk of the protective film 16 detaching or wrinkling due to increased air pressure caused by high temperatures during the preparation or use of the battery cell 10.

[0114] The vent 21 can communicate with the exhaust channel T. The positional relationship between the vent 21 and the exhaust channel T is not limited in this embodiment. For example, the projection of the vent 21 in the thickness direction Z can overlap with the projection of the exhaust channel T in the thickness direction Z, or the projection of the vent 21 in the thickness direction Z can be misaligned with the projection of the exhaust channel T in the thickness direction Z, as long as the vent 21 and the exhaust channel T can communicate with each other when the protective member 20 is connected to the battery cell 10.

[0115] In this embodiment, the vent 21 is connected to the exhaust channel T, thereby achieving communication between the protective membrane 16 and the pressure relief mechanism 15, which meets the leakage detection requirements of the pressure relief mechanism 15 and has strong practicality.

[0116] In some embodiments, the vent 21 is configured such that when the protective member 20 is connected to the battery cell 10, the projection of the vent 21 along the thickness direction Z at least partially overlaps with the projection of the exhaust channel T along the thickness direction Z.

[0117] The vent 21 and the exhaust channel T can have various structures. They can be the same or different. For example, both the vent 21 and the exhaust channel T can be narrow slit structures, or one of the vent 21 and the exhaust channel T can be a narrow slit structure and the other can be a through-hole structure, or both can be through-hole structures.

[0118] The projections of the vent 21 and the exhaust channel T in the thickness direction Z overlap. The projection of the vent 21 in the thickness direction Z can cover the projection of the exhaust channel T in the thickness direction Z, or the projection of the exhaust channel T in the thickness direction Z can also cover the projection of the vent 21 in the thickness direction Z, or the projections of the vent 21 and the exhaust channel T in the thickness direction Z only partially overlap.

[0119] The overlapping portion of the vent 21 and the exhaust channel T in the thickness direction Z allows for direct communication between the vent 21 and the exhaust channel T. In other words, gas can directly enter the overlapping portion of the exhaust channel T through the overlapping portion of the vent 21. During this process, the gas only flows within the vent 21 and the exhaust channel T without needing to go through any other additional path.

[0120] This design improves the conductivity between the vent 21 and the exhaust channel T, thereby ensuring efficient air exchange between the air outside the protective member 20 and the space between the protective membrane 16 and the pressure relief mechanism 15. This balances the air pressure and reduces the risk of the protective membrane 16 detaching or wrinkling. Simultaneously, during leak detection of the pressure relief mechanism 15, this design ensures that specific gases are effectively injected into the corresponding location of the pressure relief mechanism 15, while also guaranteeing effective detection of gas concentration near the pressure relief mechanism 15, thus improving the accuracy of leak detection.

[0121] In some embodiments, the protective member 20 is provided with a plurality of vent holes 21.

[0122] Multiple vent holes 21 are spaced apart on the protective member 20. The arrangement of the multiple vent holes 21 is not limited in this embodiment. Exemplarily, the multiple vent holes 21 can be arranged side-by-side along a single direction, or they can be arranged in an array along two directions. The shapes and dimensions of the multiple vent holes 21 can be the same or different. Furthermore, the spacing between adjacent vent holes 21 can be the same or different.

[0123] In this embodiment, the presence of multiple vent holes 21 can improve the conductivity between the space between the protective film 16 and the pressure relief mechanism 15 and the atmosphere, reduce the risk of the protective film 16 falling off or wrinkling and deforming, and at the same time improve the accuracy of the air leakage detection of the pressure relief mechanism 15.

[0124] In addition, compared to a solution with only one vent 21, the setting of multiple vent 21 can reduce the size of each vent 21 to a certain extent, thereby reducing the risk of foreign matter, dust and other impurities falling onto the protective film 16 through the vent 21 during the preparation of the battery cell 10, and further reducing the risk of the protective film 16 being scratched or bumped by external factors, resulting in deformation, lifting or even falling off.

[0125] In some embodiments, please refer to Figure 1 and Figure 6 Multiple vent holes 21 are rotationally symmetrical about the central axis O of the protective component 20.

[0126] In this embodiment, "central axis O" refers to an axis passing through the center of the protective member 20 and parallel to the thickness direction Z. Multiple vent holes 21 are rotationally symmetrically distributed about the central axis O, with rotation angles including but not limited to 30°, 60°, 90°, 120°, and 180°.

[0127] It should be noted that, in the embodiments of this application, a single vent 21 may be rotationally symmetrically distributed about the central axis O, thereby forming multiple vents 21. Alternatively, multiple vents 21 arranged side by side may together form a venting area A on the protective member 20, and the venting area A may be rotationally symmetrically distributed about the central axis O, thereby forming multiple venting areas A.

[0128] This design improves the reliability of the fit between the vent 21 and the exhaust channel T. Specifically, due to factors such as operational errors, during the connection of the protective component 20 to the battery cell 10, the protective component 20 may not be able to connect completely and correspond perfectly with the battery cell 10. The protective component 20 may be deflected at a certain angle or partially misaligned relative to the battery cell 10. In this case, the vent 21, which should correspond to the exhaust channel T, may be misaligned with the exhaust channel T, causing the vent 21 to fail to meet the requirement of conduction between the space between the pressure relief mechanism 15 and the protective membrane 16 and the atmosphere.

[0129] In this embodiment, since the multiple vent holes 21 are rotationally symmetrical with respect to the central axis O, when the protective component 20 is deflected at a certain angle relative to the battery cell 10, the other vent holes 21 can correspond to the exhaust channel T, thereby satisfying the gas communication requirement or the leakage detection requirement. This reduces the probability of vent hole 21 failure due to relative deflection or misalignment between the protective component 20 and the battery cell 10, thereby reducing the required connection accuracy between the protective component 20 and the battery cell 10.

[0130] In some embodiments, such as Figure 1 and Figure 6 As shown, the multiple vent holes 21 are symmetrical about the central axis O of the protective component 20.

[0131] The term "central symmetry" mentioned in this embodiment refers to the fact that some of the vent holes 21 can overlap with other vent holes 21 after rotating 180° around the central axis O. For example, the vent hole 21 can be a narrow slit structure extending along the first direction X. Multiple narrow slit structures are spaced apart in the second direction Y to form two vent areas A. The two vent areas A are centrally symmetrical with respect to the central axis O, and the first direction X, the second direction Y, and the thickness direction Z are perpendicular to each other.

[0132] During the connection of the protective component 20 to the battery cell 10, the protective component 20 may be deflected or misaligned relative to the battery cell 10, or it may be installed backwards. For example, the protective component 20 has a first surface and a second surface opposite each other in the thickness direction Z. Normally, the first surface of the protective component 20 is used to connect with the battery cell 10, and at this time, the first surface is located on the side of the second surface closer to the battery cell 10, and the vent hole 21 in the first venting area A can communicate with the exhaust channel T. However, when the protective component 20 is installed backwards, the second surface of the protective component 20 is connected with the battery cell 10, and the second surface is located on the side of the first surface closer to the battery cell 10. At this time, the vent hole 21 in the first venting area A cannot communicate with the exhaust channel T. However, since the second venting area A and the first venting area A are centrally symmetrical about the central axis O, the vent hole 21 in the second venting area A can communicate with the exhaust channel T, thereby satisfying the ventilation requirement.

[0133] In summary, in this embodiment, by making the multiple vent holes 21 symmetrical about the central axis O of the protective member 20, even when the protective member 20 is reversed, some of the vent holes 21 can still communicate with the exhaust channel T, thereby satisfying the needs of gas conduction and leakage detection. The protective member 20 provided in this embodiment has strong adaptability and versatility and can be applied to various situations.

[0134] In some embodiments, please refer to Figure 1 , Figures 6 to 8 The protective component 20 includes a base layer 22 and an adhesive layer 23 disposed on the surface of the base layer 22.

[0135] The base layer 22 is the most important component of the protective member 20. The base layer 22 primarily serves to protect the protective film 16, and ventilation holes 21 can be provided on the base layer 22. The material of the base layer 22 is not limited in this embodiment. Exemplarily, the base layer 22 may include metallic materials, such as copper or iron, to give it greater structural strength, thereby meeting the requirements for impact and scratch resistance.

[0136] An adhesive layer 23 is disposed on the surface of the base layer 22. The adhesive layer 23 includes, but is not limited to, adhesive. The adhesive layer 23 is used to fix the base layer 22 to the battery cell 10. The adhesive layer 23 may completely cover the surface of the base layer 22, or it may only be disposed on a portion of the surface of the base layer 22; this embodiment does not impose such limitations. Exemplarily, the adhesive layer 23 is staggered from the vent holes 21 on the base layer 22 to reduce the impact of the adhesive layer 23 on the ventilation function of the vent holes 21.

[0137] In this embodiment, the adhesive layer 23 is used to achieve a fixed connection between the base layer 22 and the battery cell 10, resulting in a simple and reliable structure. During the movement or transportation of the battery cell 10, the possibility of the protective component 20 detaching from the battery cell 10 is reduced, thereby enabling the protective component 20 to provide long-term protection for the protective film 16 during the battery cell 10 manufacturing process, thus improving the battery manufacturing yield.

[0138] In some embodiments, the protective film 16 is connected to the outer casing 11 of the battery cell 10, and the protective member 20 is configured such that when the protective member 20 is connected to the battery cell 10, the connection strength between the protective member 20 and the protective film 16 is less than the connection strength between the protective film 16 and the outer casing 11.

[0139] The connection between the protective film 16 and the outer casing 11 includes, but is not limited to, bonding and welding. In some usage scenarios of the battery cell 10, the protective component 20 will be separated from the battery cell 10. During the separation process, because there is a certain connection strength between the protective component 20 and some structures on the battery cell 10, some structures on the battery cell 10 may detach from the battery cell 10 along with the protective component 20, causing problems with the battery cell 10. For example, if there is a strong connection strength between the protective component 20 and the protective film 16, the protective film 16 may detach from the battery cell 10 along with the protective component 20 during the separation process, causing the protective film 16 to fail to continue to protect the pressure relief mechanism 15, thus creating a safety hazard.

[0140] Based on this, the connection strength between the protective member 20 and the protective film 16 is set to be less than the connection strength between the protective film 16 and the outer shell 11. Thus, during the separation process of the protective member 20 and the battery cell 10, since the force between the protective member 20 and the protective film 16 is less than the force between the protective film 16 and the outer shell 11, the protective member 20 cannot separate the protective film 16 from the outer shell 11, ensuring that the protective film 16 can cover the pressure relief mechanism 15 and protect the pressure relief mechanism 15.

[0141] It should be noted that the protective component 20 can be completely connected to the battery cell 10, meaning that all structures within the protective component 20 are connected to the battery cell 10, or the protective component 20 can be only partially connected to the battery cell 10. This embodiment does not impose any limitations on this. When the protective component 20 is only partially connected to the battery cell 10, the protective component 20 may not be connected to the protective film 16, in which case the connection strength between the protective component 20 and the protective film 16 is 0.

[0142] In some embodiments, the protective member 20 is configured such that when the protective member 20 is connected to the battery cell 10, the connection strength between the protective member 20 and the protective film 16 is less than the connection strength between the protective member 20 and the housing 11.

[0143] Specifically, the protective member 20 is easier to separate from the protective film 16 than the outer casing 11. For example, the protective member 20 is only partially connected to the battery cell 10, and is not connected to the protective film 16. This design allows the protective member 20 to preferentially separate from the protective film 16 during the separation process from the battery cell 10, thereby reducing the probability of displacement of the protective film 16 relative to the outer casing 11 due to the movement of the protective member 20. This ensures that the protective film 16 can cover the pressure relief mechanism 15, thus protecting the pressure relief mechanism 15.

[0144] In some embodiments, please refer to Figure 1 and Figure 6 The protective film 16 is connected to the first wall B of the battery cell 10. The protective member 20 includes a main body 24 and an extension 25 protruding from the main body 24. A vent 21 is provided in the main body 24. The protective member 20 is configured such that when the protective member 20 is connected to the first wall B, the extension 25 can protrude relative to the first wall B.

[0145] The outer casing 11 may include an end cap 112 and a housing 111. The pressure relief mechanism 15 may be disposed on the end cap 112 or on the housing 111. When the pressure relief mechanism 15 is disposed on the end cap 112, the protective film 16 is connected to the end cap 112, and the first wall B is a part of the structure of the end cap 112. When the pressure relief mechanism 15 is disposed on the housing 111, the protective film 16 is connected to the housing 111, and the first wall B is a part of the structure of the housing 111.

[0146] The protective component 20 includes a main body 24 and an extension 25. The main body 24 is disposed corresponding to the first wall B, wherein the main body 24 may completely cover the first wall B, or the main body 24 may only cover a portion of the structure of the first wall B. The extension 25 is connected to the main body 24, and the connection method includes, but is not limited to, bonding or welding, or the two may be an integral structure. Both the main body 24 and the extension 25 may be part of the structure within the base layer 22.

[0147] The dimensions of the extension 25 are not limited in this embodiment. For example, as shown... Figure 6 As shown, the width of the extension 25 can be smaller than the width of the main body 24. Alternatively, as... Figure 7 As shown, the width of the extension 25 can be equal to the width of the main body 24. Of course, in some other embodiments, the width of the extension 25 can also be greater than the width of the main body 24.

[0148] The extension 25 can protrude relative to the first wall B. The extension 25 can protrude only partially from the first wall B, or the entire extension 25 can protrude from the first wall B. Specifically, when the main body 24 completely covers the first wall B, the entire extension 25 protrudes from the first wall B; when the main body 24 only covers a portion of the structure of the first wall B, a portion of the structure in the extension 25 will cover the first wall B, while the other portion will protrude from the first wall B.

[0149] In some alternative embodiments, at least a portion of the structure in the extension 25 can be bent relative to the main body 24 so that at least a portion of the structure in the extension 25 can be connected and fixed to other surfaces in the housing 11 that intersect with the first wall B.

[0150] It should be noted that when the protective member 20 includes an adhesive layer 23, the adhesive layer 23 can be disposed on the extension 25 so that the extension 25 is bonded and fixed to other surfaces in the housing 11 that intersect with the first wall B, or the adhesive layer can be disposed on the main body 24 so that the main body 24 is bonded and fixed to the first wall B, or the adhesive layer can be disposed on both the extension 25 and the main body 24. This application does not limit this.

[0151] Furthermore, the extension 25 protrudes outward from the edge of the main body 24, and the extension 25 can be disposed at any edge position of the main body 24. For example, as shown in the figure, when the main body 24 has a rectangular structure, the extension 25 can be disposed on at least one side of the main body 24 in the length direction; similarly, alternatively, the extension 25 can also be disposed on at least one side of the main body 24 in the width direction.

[0152] This embodiment of the application provides an extension 25 that protrudes relative to the first wall B. This allows for separation of the protective member 20 from the battery cell 10 by pulling the extension 25, thus applying external force to the protective member 20. This reduces the risk that the protective member 20 cannot be directly separated from the battery cell 10 due to an overly tight connection between the main body 24 and the battery cell 10.

[0153] In some embodiments, when the protective member 20 is connected to the battery cell 10, at least a portion of the structure in the extension 25 is suspended.

[0154] In this embodiment, "suspended" means that after the protective member 20 is connected to the battery cell 10, at least a portion of the structure in the extension 25 is a free end and is not connected or fixed to the outer casing 11 of the battery cell 10. Optionally, when the protective member 20 is connected to the battery cell 10, the extension 25 is suspended as a whole.

[0155] In this embodiment, by suspending at least a portion of the extension 25, when it is necessary to separate the protective member 20 from the battery cell 10, the extension 25 can be easily grasped and a certain external force applied to the extension 25 to separate the protective member 20 from the battery cell 10. This design allows for better application of external force to the extension 25, thereby further reducing the difficulty of separating the protective member 20 from the battery cell.

[0156] In some embodiments, the number of extensions 25 is multiple, and the multiple extensions 25 are respectively disposed on two opposite edges of the main body 24.

[0157] As can be seen from the foregoing, the extension 25 is used to help separate the protective member 20 from the battery cell 10. Based on this, the embodiments of this application provide multiple extensions 25, so that when some of the extensions 25 fail, the separation between the protective member 20 and the battery cell 10 can still be achieved through other extensions 25.

[0158] Furthermore, multiple extensions 25 are located on two opposite edges of the main body 24. In this case, the extensions 25 can also play a positioning role to a certain extent. The relative positional relationship between the protective member 20 and the battery cell 10 is determined by the multiple extensions 25 arranged opposite to each other, thereby improving the accuracy of their positions and enabling the protective member 20 to better protect the pressure relief mechanism 15 and the protective film 16.

[0159] In some embodiments, such as Figure 1 and Figure 6 As shown, the protrusion distance of the extension 25 relative to the first wall B is D, where D satisfies: 8mm ≤ D ≤ 10mm. For example, D is one of 8mm, 8.5mm, 9mm, 9.5mm, and 10mm.

[0160] When the protrusion distance of the extension 25 relative to the first wall B is too small, there is a probability that the extension 25 will be difficult to grasp, which will make it difficult for the protective member 20 to separate from the battery cell 10, affecting production efficiency. When the protrusion distance of the extension 25 relative to the first wall B is too large, after the protective member 20 is connected to the battery cell 10, the extension 25 is prone to the risk of the protective member 20 falling off due to external factors such as scratches, which is not conducive to the protection of the battery cell 10 during production.

[0161] Therefore, in this embodiment, the protrusion distance D of the extension 25 relative to the first wall B is set between 8mm and 10mm, so as to reduce the risk of the protective member 20 being separated from the battery cell 10 due to external factors while ensuring that the protective member 20 can be easily separated from the battery cell 10.

[0162] It should be noted that when the main body 24 completely covers the first wall B, the extension 25 protrudes entirely from the first wall B, and the protrusion distance of the extension 25 relative to the first wall B is the overall size of the extension 25; when the main body 24 only covers part of the structure of the first wall B, part of the structure in the extension 25 will cover the first wall B, while other parts will protrude from the first wall B, and the protrusion distance of the extension 25 relative to the first wall B is only the size of the part of the structure in the extension 25.

[0163] Secondly, please refer to Figure 9 This application provides a method for preparing a single battery cell, the method comprising:

[0164] S100: A structure that connects a protective member to a battery cell and covers at least a portion of the protective member from the outside with a protective film.

[0165] In step S100, the protective component is disposed on the outside of the protective film. The placement of the protective component can reduce the risk of damage and deformation of the protective film during the battery cell manufacturing process, thereby reducing the probability of damage to the pressure relief mechanism. This allows the pressure relief mechanism to be actuated when the internal pressure of the battery cell reaches a predetermined threshold, ensuring the normal operation of the pressure relief mechanism and improving the safety of battery cell use.

[0166] S110: Inject electrolyte into individual battery cells.

[0167] In step S110: During the electrolyte injection process, electrolyte residue on the processing table or electrolyte that falls onto the casing during injection can easily move to the vicinity of the protective film in the battery cell. However, due to the presence of the protective components, the probability of electrolyte contact with the protective film or pressure relief mechanism is reduced, thereby reducing the probability of the pressure relief mechanism and protective film being contaminated by electrolyte and improving the safety of the battery cell.

[0168] It should be noted that steps S100 and S110 can be two adjacent steps in the battery cell fabrication process, where the protective component is connected to the battery cell before the electrolyte injection operation. Alternatively, other processes can be included between steps S100 and S110, such as the insertion of electrode assemblies into the casing, and the welding of the top cover to the casing. This design can reduce the risk of damage or breakage of the protective film due to other processes, thereby improving the yield of battery cell fabrication.

[0169] S120: Separate the protective components from the battery cells.

[0170] In step S120, after the battery cell is filled with electrolyte, the protective component can be selectively separated from the battery cell, meaning that the final battery cell may not contain a protective component. Of course, in other embodiments, the protective component may not be separated from the battery cell depending on actual needs; this application does not impose any particular limitation on this.

[0171] It should be noted that steps S110 and S120 can be two adjacent steps in the battery cell manufacturing process, i.e., the protective component is separated from the battery cell after liquid injection. Alternatively, other processes may be included between steps S110 and S120. Optionally, step S120 can be the final step in the battery cell manufacturing process.

[0172] According to some embodiments of this application, please refer to Figure 1 , Figure 4 , Figures 6 to 8 The protective member 20 is used for the battery cell 10. The battery includes a pressure relief mechanism 15 and a protective film 16 disposed outside the pressure relief mechanism 15 and connected to the first wall B on the housing 11. The protective member 20 is used to cover at least a portion of the protective film 16 from the outside.

[0173] The protective component 20 includes a base layer 22 and an adhesive layer 23. The adhesive layer 23 is disposed on the surface of the base layer 22 and is used to connect the base layer 22 to the battery cell 10. The base layer 22 includes a main body 24 and extensions 25 protruding from the main body 24. There are multiple extensions 25, which are respectively disposed on two opposite edges of the main body 24.

[0174] The main body 24 is provided with a vent hole 21. There are multiple vent holes 21. The multiple vent holes 21 are arranged symmetrically about the central axis O of the protective member 20. At least some of the vent holes 21 are configured such that when the protective member 20 is connected to the battery cell 10, the projection of the vent hole 21 along the thickness direction Z at least partially overlaps with the projection of the exhaust channel T on the protective film 16 along the thickness direction Z.

[0175] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not 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 modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: Electrode assembly; as well as The housing has an interior cavity for accommodating the electrode assembly and the electrolyte; The outer casing includes: A housing, one end of which has an opening, and a pressure relief mechanism is provided on the wall opposite to the opening; An end cap is provided, which is configured to cover the opening and be sealed to the housing. The end cap is provided with electrode terminals and a through hole. The electrode terminals are used to be electrically connected to the electrode assembly. The through hole is used for liquid injection and is located on the end cap between the two electrode terminals. A protective film, similar in shape to the pressure relief mechanism, covers the pressure relief mechanism to protect it; and A protective member is disposed on the outside of the protective membrane and covers the wall of the housing on which the pressure relief mechanism is provided. The shape of the protective member is similar to the shape of the wall of the housing on which the pressure relief mechanism is provided. The protective member is partially connected to the housing, and the connection strength between the protective member and the protective film is less than the connection strength between the protective film and the housing.

2. The battery cell according to claim 1, characterized in that, The protective component is provided with a vent hole that penetrates the protective component along its thickness direction. The vent hole is used to connect the space outside the protective component and the space between the protective membrane and the pressure relief mechanism.

3. The battery cell according to claim 2, characterized in that, The protective membrane is provided with an exhaust channel, which is connected to the space between the protective membrane and the pressure relief mechanism; the vent is connected to the exhaust channel.

4. The battery cell according to claim 3, characterized in that, The projection of the vent along the thickness direction overlaps at least partially with the projection of the exhaust channel along the thickness direction.

5. The battery cell according to claim 2, characterized in that, The protective component is provided with multiple ventilation holes.

6. The battery cell according to claim 5, characterized in that, The protective film is connected to the first wall of the housing, and the two vent holes are symmetrically arranged along the width direction of the first wall.

7. The battery cell according to claim 5, characterized in that, The plurality of vent holes are rotationally symmetrical about the central axis of the protective member.

8. The battery cell according to claim 7, characterized in that, The plurality of vent holes are centrally symmetrical about the central axis of the protective member.

9. The battery cell according to claim 1, characterized in that, The protective component includes a base layer and an adhesive layer disposed on the surface of the base layer.

10. The battery cell according to claim 1, characterized in that, The connection strength between the protective component and the protective film is less than the connection strength between the protective component and the shell.

11. The battery cell according to claim 2, characterized in that, The protective member is connected to the first wall of the housing. The protective member includes a main body and an extension protruding from the main body. The vent is provided in the main body, and the extension can protrude relative to the first wall.

12. The battery cell according to claim 11, characterized in that, At least a portion of the structure in the extension is suspended.

13. The battery cell according to claim 11, characterized in that, The number of extensions is multiple, and the multiple extensions are respectively disposed on two opposite edges of the main body.

14. The battery cell according to claim 11, characterized in that, The protrusion distance of the extension relative to the first wall is D, where D satisfies: 8mm≤D≤10mm.

15. A method for preparing a single battery cell, characterized in that, The preparation method includes the following steps: A housing, an electrode assembly, and a protective film are provided. The housing has an internal cavity for accommodating the electrode assembly and an electrolyte. The housing includes a shell and an end cap. One end of the shell has an opening, and a pressure relief mechanism is provided on the wall opposite the opening. The end cap is configured to close the opening and is sealed to the shell. The end cap has electrode terminals and a through hole. The electrode terminals are used for electrical connection with the electrode assembly. The through hole is located on the end cap between two of the electrode terminals. The protective film is similar in shape to the pressure relief mechanism and covers the pressure relief mechanism to protect it. A protective member is attached to the outside of the protective membrane and covers the wall of the housing on which the pressure relief mechanism is provided. The shape of the protective member is similar to the shape of the wall of the housing on which the pressure relief mechanism is provided. The connection strength between the protective member and the protective membrane is less than the connection strength between the protective membrane and the housing. The battery cell is injected with liquid through the through hole; The protective component is separated from the protective film and the housing.

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