Battery cell, battery device, and electric device

Abstract

The application provides a battery monomer, a battery device and a power utilization device. The battery monomer comprises a shell, an electrode assembly, a pressure relief mechanism and a liquid injection structure. The shell has a containing cavity. The shell comprises a first wall. The electrode assembly is contained in the shell. The pressure relief mechanism is arranged on the first wall. The pressure relief mechanism has a through hole. The through hole penetrates through the pressure relief mechanism along the thickness direction of the first wall. The pressure relief mechanism comprises a first part and a second part. The peripheral side of the first part is connected to the first wall. The liquid injection structure is arranged on the pressure relief mechanism. The liquid injection structure comprises a liquid injection body and a connecting part. The liquid injection body is arranged in the through hole and has a liquid injection hole. The liquid injection hole penetrates through the liquid injection body along the thickness direction. The connecting part is connected to the peripheral side of the liquid injection body. The connecting part is sealingly connected to the first part and the second part along the thickness direction. The battery monomer provided by the application is beneficial to improving the connection reliability and sealing performance of the liquid injection structure and the pressure relief mechanism, and reducing the risk of liquid injection structure falling off and electrolyte leakage.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a battery cell, a battery device, and an electrical device. Background Technology

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0003] In the development of battery cell technology, in addition to improving the performance of battery cells, their reliability is also a crucial consideration. Therefore, improving the reliability of battery cells is a continuous challenge in battery cell technology. Summary of the Invention

[0004] This application provides a battery cell, a battery device, and an electrical device, which helps to improve the reliability of the battery cell.

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

[0006] In a first aspect, the battery cell provided in this application includes a casing, an electrode assembly, a pressure relief mechanism, and a liquid injection structure. The casing has a receiving cavity and includes a first wall, and the electrode assembly is housed within the casing. The pressure relief mechanism is disposed on the first wall and has a through hole that penetrates both sides of the pressure relief mechanism along the thickness direction of the first wall. The pressure relief mechanism includes a first part and a second part stacked along the thickness direction, and the periphery of the first part is connected to the first wall. The liquid injection structure is disposed on the pressure relief mechanism and includes a liquid injection body and a connecting part. The liquid injection body passes through the through hole, and the connecting part is connected to the periphery of the liquid injection body. The connecting part is sealed to the first part and the second part on both sides along the thickness direction, respectively.

[0007] The battery cell provided in this application embodiment reduces the space occupied by the liquid injection structure on the first wall by placing it within the pressure relief mechanism. This, in turn, increases the space occupied by the pressure relief mechanism on the first wall, allowing the pressure relief mechanism to activate and form a larger exhaust channel in the event of thermal runaway of the battery cell. This facilitates rapid pressure relief of the battery cell and reduces the risk of explosion due to thermal runaway. Furthermore, the sealing connection between the liquid injection structure and the first and second parts on both sides improves the reliability and sealing of the connection between the liquid injection structure and the pressure relief mechanism, reducing the risk of liquid injection structure detachment and electrolyte leakage.

[0008] According to some embodiments of this application, the second part covers the surface of the connecting part facing the second part.

[0009] The above scheme is conducive to increasing the connection area between the second part and the connecting part, and further improving the connection reliability between the liquid injection structure and the pressure relief mechanism.

[0010] According to some embodiments of this application, the battery cell further includes a sealant layer disposed between the connecting portion and the first portion, and / or, the sealant layer is disposed between the connecting portion and the second portion.

[0011] The above scheme helps to improve the sealing of the connection between the connecting part and the second and first parts respectively, and further helps to reduce the risk of electrolyte leakage inside the battery cell.

[0012] According to some embodiments of this application, a sealant layer is provided to cover the connection portion, and the peripheral edge of the sealant layer extends beyond the peripheral edge of the connection portion.

[0013] In the above scheme, the peripheral edge of the sealant layer extends beyond the peripheral edge of the connection part, which helps to improve the sealing reliability between the connection part and the second and first parts, and further helps to reduce the risk of electrolyte leakage inside the battery cell.

[0014] According to some embodiments of this application, the dimension of the injection body is d along the radial direction of the injection body, and the dimension of the connecting part is d1, where d1≥2d.

[0015] In the above scheme, by setting d1≥2d, it is beneficial to increase the sealing area between the connecting part and the first and second parts, which in turn is beneficial to improve the connection stability and reliability of the liquid injection structure and the pressure relief mechanism, and also beneficial to improve the sealing performance between the connecting part and the second and first parts.

[0016] According to some embodiments of this application, the liquid injection body has a liquid injection hole for injecting electrolyte into the receiving cavity, and the liquid injection structure also includes a sealing pin that seals the liquid injection hole.

[0017] In the above scheme, after the electrolyte is injected into the battery cell through the injection hole, the injection hole is sealed with a sealing pin to seal the cavity and reduce the risk of electrolyte leakage inside the battery cell.

[0018] According to some embodiments of this application, the peripheral side of the second part is connected to the first wall, and the pressure relief mechanism is configured such that when the pressure inside the battery cell reaches the actuation threshold, at least a portion of the connection between the peripheral side of the second part and the first wall is separated, and at least a portion of the connection between the peripheral side of the first part and the first wall is also separated, so as to release the pressure inside the battery cell.

[0019] In the above scheme, the pressure relief mechanism is connected to the first part through the first part and the second part, which helps to improve the reliability and stability of the connection between the pressure relief mechanism and the first wall. Furthermore, the force of the second part and the first part and the first wall are used as the exhaust channel when the pressure relief mechanism is actuated, which helps to improve the timeliness and accuracy of the pressure relief mechanism actuation in the case of thermal runaway of the battery cell.

[0020] According to some embodiments of this application, the second part is provided with reinforcing ribs, and / or the first part is provided with reinforcing ribs, with the through holes and reinforcing ribs being misaligned.

[0021] In the above scheme, the addition of reinforcing ribs to at least one of the second and first parts is beneficial to improving the structural strength of the pressure relief mechanism and reducing the risk of the pressure relief mechanism accidentally opening when the battery cell is working normally. Furthermore, the staggered arrangement of the through hole and the reinforcing rib is beneficial to improving the structural stability of the reinforcing rib.

[0022] According to some embodiments of this application, the electrolyte injection body has an injection hole for injecting electrolyte into the receiving cavity. The battery cell also includes a stop portion connected to the first wall. At least a portion of the stop portion is disposed on the side of the injection hole facing the electrode assembly and is disposed opposite to and spaced apart from the injection hole along the thickness direction.

[0023] In the above scheme, at least part of the stop is provided on the side of the injection hole facing the battery cell, and is provided opposite to and spaced apart from the injection hole along the thickness direction. The stop can provide a certain stopping effect for the movement of the injection needle along the thickness direction, which helps to reduce the risk of the injection needle putting too much pressure on the pressure relief mechanism along the thickness direction and damaging the pressure relief mechanism.

[0024] According to some embodiments of this application, the stop portion includes a first stop strip and a second stop strip, the extension direction of the first stop strip intersects the extension direction of the second stop strip, and a portion of the first stop strip and a portion of the second stop strip are respectively disposed opposite to the injection hole along the thickness direction.

[0025] The above solution helps to improve the structural strength of the stop and reduce the risk of damage to the stop under the action of the injection needle.

[0026] According to some embodiments of this application, the battery cell further includes a protective element attached to the side of the first wall facing away from the electrode assembly and covering the pressure relief mechanism and the liquid injection structure.

[0027] The above solution helps reduce the risk of corrosion caused by external impurities or moisture coming into contact with the pressure relief mechanism or injection structure.

[0028] According to some embodiments of this application, the first wall has a pressure relief hole that penetrates the first wall and includes a first hole segment, a second hole segment, and a first stepped surface. The first hole segment is located on the side of the second hole segment near the electrode assembly, and the radial dimension of the first hole segment is smaller than the radial dimension of the second hole segment. The first stepped surface connects the hole wall of the first hole segment and the hole wall of the second hole segment. The pressure relief mechanism is located in the first hole segment, and the protective member is connected to the first stepped surface.

[0029] In the above scheme, at least part of the protective component is located in the second hole. The first hole segment can provide a certain stopping effect for the protective component, reduce the risk of the protective component falling off, and help reduce the distance of the protective component protruding from the outer surface of the first wall, so as to reduce the risk of the protective component interfering with other structures.

[0030] According to some embodiments of this application, the protective element is located inside the second hole segment.

[0031] The above solution helps to further reduce the risk of protective components falling off and also helps to further reduce the risk of interference between protective components and other structures.

[0032] According to some embodiments of this application, along the thickness direction, the orthographic projection of the end face of the liquid injection structure away from the electrode assembly is located inside the first hole segment.

[0033] In the above scheme, the injection structure does not protrude from the outer surface of the first wall to reduce the risk of interference between the injection structure and other structures, thus improving the structural stability of the injection structure. Furthermore, the injection structure does not protrude from the first step surface to reduce the risk of interference between the injection structure and the protective component, further improving the structural stability of the protective component.

[0034] According to some embodiments of this application, the first part has a scoring area, and the pressure relief mechanism is configured to open with the scoring area as the boundary when the pressure inside the battery cell reaches the actuation threshold, so as to release the pressure inside the battery cell. The liquid injection structure is offset from the scoring area.

[0035] In the above scheme, by setting the injection structure and the scoring area to be misaligned, the influence of the injection mechanism on the wind direction of the pressure relief mechanism is reduced, which helps to improve the timeliness and accuracy of the pressure relief mechanism.

[0036] According to some embodiments of this application, the liquid injection body has a liquid injection hole for injecting electrolyte into the receiving cavity. The liquid injection hole includes a third hole segment, a fourth hole segment, and a second stepped surface. The third hole segment is located on the side of the fourth hole segment facing the electrode assembly, and the diameter of the third hole segment is smaller than the diameter of the fourth hole segment. The second stepped surface connects the inner wall of the third hole segment and the inner wall of the fourth hole segment.

[0037] In the above scheme, during the process of injecting electrolyte using the injection needle, the injection hole is structurally matched with the injection needle through the third hole section, the fourth hole section, and the second step surface, which facilitates the matching between the injection hole and the injection needle and improves the injection stability.

[0038] Secondly, the battery device provided in the embodiments of this application includes the battery cell provided in any of the above embodiments.

[0039] The battery device provided in this application has the same technical effect as the battery cell provided in any of the above embodiments, and will not be described again here.

[0040] Thirdly, the electrical device provided in the embodiments of this application includes the battery device provided in the above embodiments, and the battery device is used to provide electrical energy.

[0041] The electrical device provided in this application embodiment has the same technical effect as the battery device provided in this application embodiment, and will not be described again here.

[0042] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0043] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the vehicle structure provided in an embodiment of this application;

[0045] Figure 2 This is a schematic diagram of the structure of the battery device provided in the embodiments of this application;

[0046] Figure 3 This is a schematic diagram of the structure of a battery cell assembly in a battery device provided in an embodiment of this application;

[0047] Figure 4 This is a schematic diagram of the exploded structure of a single battery cell in a battery device provided in an embodiment of this application;

[0048] Figure 5 This is an exploded structural diagram of a portion of the battery cell provided in an embodiment of this application;

[0049] Figure 6 A bottom view of a portion of the structure of a battery cell provided in an embodiment of this application;

[0050] Figure 7 This is a partial structural schematic diagram of a battery cell provided in an embodiment of this application;

[0051] Figure 8 This is a schematic diagram of the liquid injection structure in a battery cell provided in an embodiment of this application.

[0052] The accompanying drawings are not necessarily drawn to scale.

[0053] Explanation of reference numerals in the attached figures:

[0054] 1-Vehicle; 1a-Motor; 1b-Controller;

[0055] 10 - Battery assembly; 11 - Housing; 111 - First sub-housing; 112 - Second sub-housing;

[0056] 20-Battery cell module;

[0057] 30-Battery cell; 31-Casing; 31a-Receiving cavity; 311-Casing; 312-End cap; 313-First wall; 313a-Pressure relief hole; 3131a-First hole segment; 3132a-Second hole segment; 3133a-First stepped surface; 32-Electrode assembly; 321-Electrode body; 322-Electrode tab; 33-Electrode terminal;

[0058] 40 - Pressure relief mechanism; 40a - Through hole; 41 - First part; 42 - Second part; 43 - Reinforcing rib;

[0059] 50 - Injection structure; 51 - Injection body; 51a - Injection hole; 511a - Third hole section; 512a - Fourth hole section; 513a - Second step surface; 52 - Connecting part;

[0060] 60 - Sealant layer;

[0061] 70 - Stop section; 71 - First stop bar; 72 - Second stop bar;

[0062] X - Thickness direction. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0064] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0065] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0066] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

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

[0069] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0070] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells into a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0071] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cell assemblies housed within the housing.

[0072] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be housed in the housing by fixing the battery module in the housing.

[0073] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0074] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0075] In some embodiments, the battery device may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0076] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0077] The battery cell may be, but is not limited to, lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc.

[0078] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0079] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0080] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0081] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be made of stainless steel, copper, aluminum, carbon electrodes, carbon, nickel, or titanium with a silver-plated surface. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0082] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for battery cells may also be used.

[0083] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0084] As an example, the negative electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, copper, aluminum, carbon electrode, carbon, nickel, or titanium, etc.

[0085] In some embodiments, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0086] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0087] In some embodiments, the diaphragm is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0088] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0089] In some embodiments, the membrane is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0090] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0091] In some implementations, the electrode assembly is a stacked structure.

[0092] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0093] In some embodiments, the housing includes an end cap and a casing, the casing having an opening, and the end cap closing the opening to form a sealed space for accommodating substances such as electrode assemblies and electrolytes. The casing may have one or more openings. The end cap may also be provided one or more times.

[0094] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab of the electrode assembly. The electrode terminal can be directly connected to the tab or indirectly connected to the tab through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0095] In some implementations, an explosion-proof valve is provided on the housing. The explosion-proof valve is used to release the internal pressure of the battery cells.

[0096] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. There are no particular limitations in the embodiments of this application.

[0097] Battery cells typically have a pressure relief mechanism and an electrolyte injection port on their casing. During the manufacturing process, electrolyte is injected into the casing through the injection port. When the internal temperature or pressure of the battery cell becomes abnormal, the pressure relief mechanism releases the waste material inside the battery cell to reduce the risk of explosion due to thermal runaway.

[0098] In related technologies, the pressure relief mechanism and the liquid injection hole are respectively located on the same side wall of the outer casing, with the two spaced apart. Each occupies a portion of the space of the first wall of the outer casing. Thus, the presence of the liquid injection hole limits the size of the space occupied by the pressure relief mechanism on the first wall. Consequently, in the event of thermal runaway of a battery cell, the opening for discharging waste after the pressure relief mechanism is activated is relatively small, limiting the discharge rate of waste inside the battery cell. This results in untimely pressure relief inside the battery cell, which seriously affects the reliability of the battery cell.

[0099] In view of this, the battery cell provided in this application embodiment includes a casing, an electrode assembly, a pressure relief mechanism, and a liquid injection structure. The casing has a receiving cavity and includes a first wall, and the electrode assembly is housed within the casing. The pressure relief mechanism is disposed on the first wall and has a through hole that penetrates both sides of the pressure relief mechanism along the thickness direction of the first wall. The pressure relief mechanism includes a first part and a second part stacked along the thickness direction, and the periphery of the first part is connected to the first wall. The liquid injection structure is disposed on the pressure relief mechanism and includes a liquid injection body and a connecting part. The liquid injection body passes through the through hole, and the connecting part is connected to the periphery of the liquid injection body and disposed between the first part and the second part. The connecting part is sealed to the first part and the second part respectively along the thickness direction.

[0100] The battery cell provided in this application embodiment reduces the space occupied by the liquid injection structure on the first wall by placing it within the pressure relief mechanism. This, in turn, increases the space occupied by the pressure relief mechanism on the first wall, allowing the pressure relief mechanism to activate and form a larger exhaust channel in the event of thermal runaway of the battery cell. This facilitates rapid pressure relief of the battery cell and reduces the risk of explosion due to thermal runaway. Furthermore, the sealing connection between the liquid injection structure and the first and second parts on both sides improves the reliability and sealing of the connection between the liquid injection structure and the pressure relief mechanism, reducing the risk of liquid injection structure detachment and electrolyte leakage.

[0101] The technical solutions described in the embodiments of this application are applicable to battery packs and electrical devices that use battery packs.

[0102] The battery device disclosed in this application can be used, but is not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be constructed using the battery device disclosed in this application.

[0103] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric bicycles, electric motorcycles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0104] For ease of explanation, the following embodiments will be described using a vehicle 1 as an example of an electrical device according to an embodiment of this application.

[0105] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1 provided in an embodiment of this application. Vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 10 is installed inside vehicle 1, and the battery device 10 can be located at the bottom, front, or rear of vehicle 1. The battery device 10 can be used to power vehicle 1; for example, the battery device 10 can serve as the operating power source for vehicle 1's electrical system, such as meeting the power requirements for starting, navigation, and operation of vehicle 1.

[0106] The vehicle 1 may also include a controller 1b and a motor 1a. The controller 1b is used to control the battery device 10 to supply power to the motor 1a, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0107] In some embodiments of this application, the battery device 10 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0108] Please refer to Figure 2 and Figure 3 , Figure 2 This is a schematic diagram of the structure of the battery device 10 provided in the embodiments of this application. Figure 3 This is an exploded view of the battery cell 30 provided in an embodiment of this application. The battery device 10 includes a housing 11 and a battery cell 30, with the battery cell 30 housed within the housing 11. The housing 11 provides a space for the battery cell 30, and the housing 11 can have various structures. In some embodiments, the housing 11 may include a first sub-housing 111 and a second sub-housing 112, which overlap each other, and together define a space for accommodating the battery cell 30. The second sub-box 112 can be a hollow structure with one end open, and the first sub-box 111 can be a plate-like structure. The first sub-box 111 covers the opening side of the second sub-box 112 so that the first sub-box 111 and the second sub-box 112 together define the accommodating space. Alternatively, the first sub-box 111 and the second sub-box 112 can both be hollow structures with one side open, and the opening side of the first sub-box 111 covers the opening side of the second sub-box 112.

[0109] In the battery device 10, there can be multiple battery cells 30, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 30 are connected in both series and parallel configurations. Multiple battery cells 30 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 30 is housed within the housing 11. Alternatively, the battery device 10 can also consist of multiple battery cells 30 first connected in series, parallel, or in a mixed manner to form a battery cell assembly 20, and then the multiple battery cell assemblies 20 are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within the housing 11. The battery device 10 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 30.

[0110] Among them, the battery cell 30 can be a secondary battery or a primary battery; the battery cell 30 can also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited to these.

[0111] Please refer to Figure 4 , Figure 4 This is a schematic diagram of the exploded structure of a battery cell 30 provided in an embodiment of this application. Figure 4 As shown, the battery cell 30 includes a housing 31, an electrode assembly 32, and electrode terminals 33. The housing 31 includes a casing 311 and an end cap 312. The casing 311 has an opening, and the end cap 312 closes the opening to isolate the internal environment of the battery cell 30 from the external environment.

[0112] The housing 311 is a component used to cooperate with the end cap 312 to form the internal environment of the battery cell 30, wherein the formed internal environment can accommodate the electrode assembly 32, electrolyte, and other components. The housing 311 and the end cap 312 can be independent components. The housing 311 can have various shapes and sizes. Specifically, the shape of the housing 311 can be determined according to the specific shape and size of the electrode assembly 32. The housing 311 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, and plastic.

[0113] End cap 312 refers to a component that covers the opening of housing 311 to isolate the internal environment of battery cell 30 from the external environment. The shape of end cap 312 can be adapted to the shape of housing 311 to fit it. Optionally, end cap 312 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 312 is not easily deformed under pressure and impact, giving battery cell 30 higher structural strength and improved reliability. Functional components such as electrode terminals 33 can be provided on end cap 312. Electrode terminals 33 can be used for electrical connection with electrode assembly 32 to output or input electrical energy to battery cell 30. The material of end cap 312 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose special limitations on this. In some embodiments, an insulating structure may be provided on the inner side of the end cap 312. The insulating structure can be used to isolate the electrical connection components within the housing 311 from the end cap 312 to reduce the risk of short circuits. For example, the insulating structure may be made of plastic, rubber, etc.

[0114] Electrode assembly 32 is the component in the battery cell 30 where electrochemical reactions occur. The housing 311 may contain one or more electrode assemblies 32. The electrode assembly 32 is mainly formed by winding or stacking positive and negative electrode plates, and typically a separator is provided between the positive and negative electrode plates to separate them and prevent internal short circuits. The portions of the positive and negative electrode plates containing active material constitute the electrode body 321 of the electrode assembly 32, while the portions of the positive and negative electrode plates without active material each constitute a tab 322. The positive and negative tabs may be located together at one end of the electrode body 321 or separately at both ends of the electrode body 321. During the charging and discharging process of the battery cell 30, the positive and negative active materials react with the electrolyte, and the tabs 322 connect to the electrode terminals 33 to form a current loop.

[0115] Firstly, such as Figure 4 and Figure 5As shown, the battery cell 30 provided in this embodiment includes a housing 31, an electrode assembly 32, a pressure relief mechanism 40, and a liquid injection structure 50. The housing 31 has a receiving cavity 31a and includes a first wall 313. The electrode assembly 32 is housed within the housing 31. The pressure relief mechanism 40 is disposed on the first wall 313 and has a through hole 40a that penetrates both sides of the pressure relief mechanism 40 along the thickness direction X of the first wall 313. The pressure relief mechanism 40 includes a first part 41 and a second part 42 stacked along the thickness direction X. The periphery of the first part 41 is connected to the first wall 313. The liquid injection structure 50 is disposed on the pressure relief mechanism 40 and includes a liquid injection body 51 and a connecting part 52. The liquid injection body 51 passes through the through hole 40a, and the connecting part 52 is connected to the periphery of the liquid injection body 51. The connecting part 52 is sealed to the first part 41 and the second part 42 on both sides along the thickness direction X, respectively.

[0116] The pressure relief mechanism 40 can be an explosion-proof valve or similar device. It is activated when the air pressure inside the casing 31 reaches its pressure relief threshold. "Activation" of the pressure relief mechanism 40 means that it operates or is activated to a certain state, thereby releasing the pressure and temperature inside the battery cell 30. The actions of the pressure relief mechanism 40 may include, but are not limited to: movement of components within the mechanism to form an exhaust channel; rupture, breakage, tearing, or opening of at least a portion of the mechanism; etc. When activated, the high-temperature, high-pressure material inside the battery cell 30 is discharged as waste from the activated portion. This method allows for pressure and temperature relief of the battery cell 30 under controllable pressure or temperature, thereby reducing the possibility of potentially more serious accidents.

[0117] Therefore, when the pressure relief mechanism 40 is actuated, at least part of the connection between the periphery of the first part 41 and the first wall 313 may rupture, forming an exhaust channel. The corresponding pressure relief mechanism 40 is a diaphragm type. Alternatively, the first part 41 may be provided with a weak area. When the pressure relief mechanism 40 is actuated, the weak area of ​​the first part 41 may rupture and form an exhaust channel. In this case, the pressure relief mechanism 40 may be a grooved type. In order to improve the connection reliability between the injection structure 50 and the second part 42, the through hole 40a may avoid the weak area or be grooved.

[0118] The connecting part 52 of the injection structure 50 is connected to the periphery of the injection body 51. The connecting part 52 and the injection body 51 can be integrally formed, or the connecting part 52 can be connected to the periphery of the injection body 51 by welding, snap-fit ​​or other connection methods. Optionally, the connecting part 52 is arranged around the periphery of the injection body 51.

[0119] The electrolyte injection body 51 is inserted through the through hole 40a. The electrolyte injection body 51 may have an electrolyte injection hole 51a. The electrolyte injection hole 51a penetrates both sides of the electrolyte injection body 51 along the thickness direction X. The electrolyte injection hole 51a connects the receiving cavity 31a and the space outside the battery cell 30. In the production process of the battery cell 30, electrolyte can be injected into the outer casing 31 through the electrolyte injection hole 51a. After the electrolyte is injected, the electrolyte injection hole 51a can be sealed by a sealing pin or other structure to seal the receiving cavity 31a.

[0120] The connecting part 52 is located between the first part 41 and the second part 42. The connecting part 52 is sealed to the first part 41 and the second part 42 on both sides along the thickness direction X. The sealing connection between the connecting part 52 and the first part 41 and the second part 42 respectively has a certain sealing effect on the through hole 40a, which helps to reduce the risk of electrolyte leakage through the through hole 40a.

[0121] The sealing connection between the connecting part 52 and the second part 42 and the first part 41 can be achieved by providing a sealing ring or other structure between the connecting part 52 and the first part 41, or between the connecting part 52 and the second part 42. Alternatively, a sealant or other sealant can be provided between the connecting part 52 and the first part 41, or between the connecting part 52 and the second part 42.

[0122] Optionally, the periphery of the second part 42 may not be connected to the first wall 313, or the periphery of the second part 42 may also be connected to the first wall 313, and at least part of the connection between the second part 42 and the first wall 313 may rupture when the pressure relief mechanism 40 is actuated.

[0123] It is understandable that by placing the liquid injection structure 50 on the pressure relief mechanism 40, the space occupied by the liquid injection structure 50 in the first wall 313 can be reduced, thereby increasing the space occupied by the pressure relief mechanism 40 in the first wall 313. In the event of thermal runaway of the battery cell 30, the pressure relief mechanism 40 can be activated to form a larger exhaust channel, which facilitates the timely discharge of high-temperature and high-pressure emissions from the battery cell 30 and reduces the possibility of the battery cell 30 exploding due to thermal runaway.

[0124] The injection structure 50 is sealed to the second part 42 and the first part 41 on both sides along the thickness direction X via the connecting part 52, which helps to improve the sealing performance of the connection between the injection structure 50 and the pressure relief mechanism 40, and facilitates a more stable connection between the injection structure 50 and the pressure relief mechanism 40.

[0125] The battery cell 30 provided in this embodiment reduces the space occupied by the liquid injection structure 50 in the first wall 313 by placing it in the pressure relief mechanism 40. This increases the space occupied by the pressure relief mechanism 40 in the first wall 313, allowing the pressure relief mechanism 40 to actuate and form a larger exhaust channel in the event of thermal runaway of the battery cell 30. This facilitates rapid pressure relief of the battery cell 30 and reduces the risk of explosion due to thermal runaway. Furthermore, the connection 52 of the liquid injection structure 50 is sealed to the first part 41 and the second part 42 on both sides, improving the reliability and sealing of the connection between the liquid injection structure 50 and the pressure relief mechanism 40, and reducing the risk of the liquid injection structure 50 detaching and electrolyte leakage.

[0126] In some embodiments, the second part 42 covers the surface of the connecting part 52 on the side facing the second part 42.

[0127] Thus, the edge of the second part 42 perpendicular to the thickness direction X is flush with the edge of the connecting part 52, or the edge of the second part 42 perpendicular to the thickness direction X extends beyond the second part 42, which helps to increase the connection area between the second part 42 and the connecting part 52, and further improves the connection reliability between the liquid injection structure 50 and the pressure relief mechanism 40.

[0128] In some embodiments, such as Figure 4 and Figure 5 As shown, the battery cell 30 also includes a sealant layer 60, which is disposed between the connecting portion 52 and the first portion 41, and / or, the sealant layer 60 is disposed between the connecting portion 52 and the second portion 42.

[0129] The sealant layer 60 can be formed by curing fluid adhesives such as tab adhesives. The sealant layer 60 has good sealing performance and good corrosion resistance. It is relatively stable for long-term use, which helps to improve the sealing performance of the connection part 52 to the second part 42 and the first part 41 respectively, and further helps to reduce the risk of electrolyte leakage inside the battery cell 30.

[0130] In some embodiments, the sealant layer 60 covers the connection portion 52, and the peripheral edge of the sealant layer 60 extends beyond the peripheral edge of the connection portion 52.

[0131] The peripheral edge of the sealant layer 60 extends beyond the peripheral edge of the connection portion 52, which helps to improve the sealing reliability between the connection portion 52 and the second portion 42 and the first portion 41, and further helps to reduce the risk of electrolyte leakage inside the battery cell 30.

[0132] In some embodiments, such as Figure 6 As shown, along the radial direction of the injection body 51, the dimension of the injection body 51 is d, and the dimension of the connecting part 52 is d1, where d1≥2d.

[0133] It is understandable that the larger d1 is, the more beneficial it is to increase the connection area between the connecting part 52 and the second part 42 and the first part 41, and thus the more beneficial it is to improve the connection reliability between the connecting part 52 and the pressure relief mechanism 40.

[0134] After systematic analysis and long-term practice, the inventors discovered that by setting d1≥2d, it is beneficial to increase the sealing area between the connecting part 52 and the first part 41 and the second part 42, which in turn is beneficial to improve the connection stability and reliability between the liquid injection structure 50 and the pressure relief mechanism 40, and also beneficial to improve the sealing performance between the connecting part 52 and the second part 42 and the first part 41.

[0135] In some embodiments, the injection body 51 has an injection hole 51a for injecting electrolyte into the receiving cavity 31a, and the injection structure 50 further includes a sealing pin that seals the injection hole 51a.

[0136] Optionally, the sealing pin can be detachably plugged into the injection hole 51a to facilitate the re-injection of electrolyte into the receiving cavity 31a during subsequent use or production. Of course, the sealing pin can also be non-detachably plugged into the injection hole 51a.

[0137] After the electrolyte is injected into the battery cell 30 through the injection hole 51a, the injection hole 51a is sealed with a sealing pin to seal the receiving cavity 31a and reduce the risk of electrolyte leakage inside the battery cell 30.

[0138] In some embodiments, the periphery of the second part 42 is connected to the first wall 313, and the pressure relief mechanism 40 is configured to at least partially separate the connection between the periphery of the second part 42 and the first wall 313, and at least partially separate the connection between the periphery of the first part 41 and the first wall 313, when the pressure inside the battery cell 30 reaches the actuation threshold, so as to release the pressure inside the battery cell 30.

[0139] The connection between the periphery of the second part 42 and the first wall 313 can be a welded connection, etc. Similarly, the connection between the periphery of the first part 41 and the first wall 313 can also be a welded connection, etc. The connection strength between the second part 42 or the first part 41 and the first wall 313 can be set according to the actuation threshold of the pressure relief mechanism 40, so that when the internal pressure of the battery cell 30 reaches the actuation threshold of the battery cell 30, at least part of the connection between the second part 42 and the first part 41 and the first wall 313 will separate from each other.

[0140] The pressure relief mechanism 40 is connected to the first part 41 through the first part 41 and the second part 42, which helps to improve the reliability and stability of the connection between the pressure relief mechanism 40 and the first wall 313. Furthermore, the combined force of the second part 42 and the first part 41 and the first wall 313 serves as the exhaust channel when the pressure relief mechanism 40 is actuated. In the event of thermal runaway of the battery cell 30, this helps to improve the timeliness and accuracy of the actuation of the pressure relief mechanism 40.

[0141] In some embodiments, such as Figure 4 and Figure 5 As shown, the second part 42 is provided with a reinforcing rib 43, and / or the first part 41 is provided with a reinforcing rib 43, and the through hole 40a is offset from the reinforcing rib 43.

[0142] The addition of reinforcing ribs 43 to the second part 42 improves its structural strength, while the addition of reinforcing ribs 43 to the first part 41 improves its structural strength. The through-hole 40a is offset from the reinforcing rib 43, ensuring that the through-hole 40a does not penetrate the reinforcing rib 43, thus maintaining the structural integrity of the reinforcing rib 43 and improving the connection stability between the injection structure 50 and the pressure relief mechanism 40.

[0143] Therefore, providing a reinforcing rib 43 on at least one of the second part 42 and the first part 41 is beneficial to improving the structural strength of the pressure relief mechanism 40 and reducing the risk of the pressure relief mechanism 40 accidentally opening when the battery cell 30 is working normally. Furthermore, the staggered arrangement of the through hole 40a and the reinforcing rib 43 is beneficial to improving the structural stability of the reinforcing rib 43.

[0144] In some embodiments, such as Figure 6 As shown, the electrolyte injection body 51 has an injection hole 51a for injecting electrolyte into the receiving cavity 31a. The battery cell 30 also includes a stop portion 70, which is connected to the first wall 313. At least a portion of the stop portion 70 is provided on the side of the injection hole 51a facing the electrode assembly 32, and is opposite to and spaced apart from the injection hole 51a along the thickness direction X.

[0145] Optionally, the first wall 313 may include an insulating element and a metal element, and the stop portion 70 may be connected to the insulating element, or the stop portion 70 may be connected to the metal element.

[0146] During the process of injecting electrolyte into the battery cell 30, an injection needle is typically used to insert the electrolyte into the injection hole 51a and inject it into the receiving cavity 31a. By providing at least a portion of a stop portion 70 on the side of the injection hole 51a facing the battery cell 30, and being positioned opposite and spaced apart from the injection hole 51a along the thickness direction X, the stop portion 70 can provide a certain degree of restraint on the movement of the injection needle along the thickness direction X. This helps to reduce the risk of excessive pressure from the injection needle on the pressure relief mechanism 40 along the thickness direction X, which could damage the pressure relief mechanism 40.

[0147] In some embodiments, such as Figure 6 As shown, the stop portion 70 includes a first stop strip 71 and a second stop strip 72. The extension direction of the first stop strip 71 intersects the extension direction of the second stop strip 72. A portion of the first stop strip 71 and a portion of the second stop strip 72 are respectively disposed opposite to the injection hole 51a along the thickness direction X.

[0148] This helps to improve the structural strength of the stop part 70 and reduce the risk of damage to the stop part 70 under the action of the injection needle.

[0149] In some embodiments, the battery cell 30 further includes a protective member attached to the side of the first wall 313 facing away from the electrode assembly 32 and covering the pressure relief mechanism 40 and the liquid injection structure 50.

[0150] The protective component can be a plastic film, etc. The protective component covers the pressure relief mechanism 40 and the liquid injection structure 50, which helps to reduce the risk of corrosion caused by external impurities or water vapor coming into contact with the pressure relief mechanism 40 or the liquid injection structure 50.

[0151] In some embodiments, such as Figure 7 As shown, the first wall 313 has a pressure relief hole 313a, which penetrates the first wall 313 and includes a first hole segment 3131a, a second hole segment 3132a, and a first stepped surface 3133a. The first hole segment 3131a is located on the side of the second hole segment 3132a near the electrode assembly 32, and the radial dimension of the first hole segment 3131a is smaller than the radial dimension of the second hole segment 3132a. The first stepped surface 3133a connects the hole wall of the first hole segment 3131a and the hole wall of the second hole segment 3132a. The pressure relief mechanism 40 is located in the first hole segment 3131a, and the protective member is connected to the first stepped surface 3133a.

[0152] Optionally, the pressure relief hole 313a can be a round hole or an oblong hole, etc. The radial dimension of the first hole segment 3131a can be the dimension of the first hole segment 3131a in any direction perpendicular to the thickness direction X. If the radial dimension of the first hole segment 3131a is smaller than the radial dimension of the second hole segment 3132a, then the second hole segment 3132a is configured to cover the first hole segment 3131a.

[0153] The pressure relief mechanism 40 is located in the first hole section 3131a, and the protective member is connected to the first step surface 3133a. At least part of the protective member is located in the second hole. The first hole section 3131a can provide a certain stopping effect for the protective member, reduce the risk of the protective member falling off, and help reduce the distance of the protective member protruding from the outer surface of the first wall 313, so as to reduce the risk of the protective member interfering with other structures.

[0154] In some embodiments, the protective element is located inside the second hole segment 3132a.

[0155] Optionally, the outer surface of the protective member may be flush with the outer surface of the first wall 313, or the outer surface of the protective member may be spaced apart from the surface of the first wall 313, and the outer surface of the protective member may be located within the second hole section 3132a.

[0156] This helps to further reduce the risk of protective components falling off, and also helps to further reduce the risk of protective components interfering with other structures.

[0157] In some embodiments, along the thickness direction X, the orthographic projection of the end face of the liquid injection structure 50 on the side away from the electrode assembly 32 is located inside the first hole segment 3131a.

[0158] Optionally, the end face of the liquid injection structure 50 away from the electrode assembly 32 may be flush with the end face of the first hole segment 3131a, or the end face of the liquid injection structure 50 away from the electrode assembly 32 may be located inside the first hole segment 3131a.

[0159] Thus, the injection structure 50 is not protruding from the outer surface of the first hole section 3131a, which reduces the risk of interference between the injection structure 50 and the protective component and helps to improve the structural stability of the injection structure 50.

[0160] In some embodiments, the first part 41 has a scoring area, and the pressure relief mechanism 40 is configured to open with the scoring area as the boundary when the pressure inside the battery cell 30 reaches the actuation threshold, so as to release the pressure inside the battery cell 30. The liquid injection structure 50 is offset from the scoring area.

[0161] The pressure relief mechanism 40 can be integrally formed with the first wall 313. When the pressure inside the battery cell 30 reaches the actuation threshold of the pressure relief mechanism 40, the grooved area breaks, and the pressure relief mechanism 40 is actuated.

[0162] By setting the injection structure 50 to be misaligned with the scoring area, the influence of the injection mechanism on the wind direction of the pressure relief mechanism 40 is reduced, which helps to improve the timeliness and accuracy of the pressure relief mechanism 40.

[0163] In some embodiments, such as Figure 8As shown, the liquid injection body 51 has a liquid injection hole 51a, which is used to inject electrolyte into the receiving cavity 31a. The liquid injection hole 51a includes a third hole section 511a, a fourth hole section 512a, and a second step surface 513a. The third hole section 511a is located on the side of the fourth hole section 512a facing the electrode assembly 32, and the diameter of the third hole section 511a is smaller than the diameter of the fourth hole section 512a. The second step surface 513a connects the inner wall of the third hole section 511a and the inner wall of the fourth hole section 512a.

[0164] Optionally, the third hole segment 511a and the fourth hole segment 512a can be selected as round holes or oblong holes, depending on the shape of the injection needle.

[0165] Thus, during the process of injecting electrolyte using the injection needle, the injection hole 51a is structurally matched with the injection needle through the third hole section 511a, the fourth hole section 512a, and the second step surface 513a, which facilitates the matching between the injection hole 51a and the injection needle and improves the stability of the injection.

[0166] Secondly, the battery device 10 provided in the embodiments of this application includes the battery cell 30 provided in any of the above embodiments.

[0167] The battery device 10 provided in this application embodiment has the same technical effect as the battery cell 30 provided in any of the above embodiments, and will not be described again here.

[0168] Thirdly, the electrical device provided in the embodiments of this application includes the battery device 10 provided in the above embodiments, and the battery device 10 is used to provide electrical energy.

[0169] The electrical device provided in this application embodiment has the same technical effect as the battery device 10 provided in this application embodiment, and will not be described again here.

[0170] In some embodiments, such as Figures 4 to 8As shown, the battery cell 30 includes a housing 31, an electrode assembly 32, a pressure relief mechanism 40, a sealant layer 60, a protective component, and a liquid injection structure 50. The housing 31 has a receiving cavity 31a and includes a first wall 313. The electrode assembly 32 is housed within the housing 31. The pressure relief mechanism 40 is disposed on the first wall 313 and has a through hole 40a that penetrates both sides of the pressure relief mechanism 40 along the thickness direction X of the first wall 313. The pressure relief mechanism 40 includes a first part 41 and a second part 42 stacked along the thickness direction X. The periphery of the first part 41 is connected to the first wall 313. The liquid injection structure 50 is disposed on the pressure relief mechanism 40 and includes a liquid injection body 51, a sealing pin, and a connecting part 52. The liquid injection body 51 passes through the through hole 40a and has a liquid injection hole 51a. The sealing pin seals the liquid injection hole 51a. Injection hole 51a penetrates both sides of injection body 51 along the thickness direction X and communicates with receiving cavity 31a. Connecting part 52 is connected to the periphery of injection body 51, and the two sides of connecting part 52 along the thickness direction X are respectively sealed to first part 41 and second part 42. Second part 42 covers the surface of connecting part 52 facing second part 42. Sealing layer 60 is disposed between connecting part 52 and first part 41, and between connecting part 52 and second part 42. Sealing layer 60 covers connecting part 52, and the peripheral edge of sealing layer 60 extends beyond the peripheral edge of connecting part 52. Along the radial direction of injection body 51, the dimension of injection body 51 is d, and the dimension of connecting part 52 is d1, where d1 ≥ 2d. The periphery of the second part 42 is connected to the first wall 313. The pressure relief mechanism 40 is configured such that when the pressure inside the battery cell 30 reaches the actuation threshold, at least a portion of the connection between the periphery of the second part 42 and the first wall 313 is separated, and at least a portion of the connection between the periphery of the first part 41 and the first wall 313 is also separated, to release the pressure inside the battery cell 30. The second part 42 is provided with a reinforcing rib 43, and the first part 41 is also provided with a reinforcing rib 43. The through hole 40a is offset from the reinforcing rib 43. The battery cell 30 also includes a stop part 70, which is connected to the first wall 313. At least a portion of the stop part 70 is located on the side of the injection hole 51a facing the electrode assembly 32, and is opposite to and spaced apart from the injection hole 51a along the thickness direction X. The stop portion 70 includes a first stop strip 71 and a second stop strip 72. The extending direction of the first stop strip 71 intersects the extending direction of the second stop strip 72. A portion of the first stop strip 71 and a portion of the second stop strip 72 are respectively disposed opposite to the injection hole 51a along the thickness direction X. The protective member is attached to the side of the first wall 313 facing away from the electrode assembly 32 and covers the pressure relief mechanism 40 and the injection structure 50.The first wall 313 has a pressure relief hole 313a that penetrates the first wall 313 and includes a first hole segment 3131a, a second hole segment 3132a, and a first stepped surface 3133a. The first hole segment 3131a is located on the side of the second hole segment 3132a closest to the electrode assembly 32, and the radial dimension of the first hole segment 3131a is smaller than that of the second hole segment 3132a. The first stepped surface 3133a connects the hole walls of the first hole segment 3131a and the second hole segment 3132a. A pressure relief mechanism 40 is located inside the first hole segment 3131a, and a protective member is connected to the first stepped surface 3133a and located inside the second hole segment 3132a. Along the thickness direction X, the orthographic projection of the end face of the liquid injection structure 50 on the side away from the electrode assembly 32 is located inside the first wall 313. The injection hole 51a includes a third hole section 511a, a fourth hole section 512a, and a second stepped surface 513a. The third hole section 511a is located on the side of the fourth hole section 512a facing the electrode assembly 32, and the diameter of the third hole section 511a is smaller than the diameter of the fourth hole section 512a. The second stepped surface 513a connects the inner wall of the third hole section 511a and the inner wall of the fourth hole section 512a.

[0171] The battery cell 30 provided in this embodiment reduces the space occupied by the liquid injection structure 50 in the first wall 313 by placing it in the pressure relief mechanism 40. This increases the space occupied by the pressure relief mechanism 40 in the first wall 313, allowing the pressure relief mechanism 40 to actuate and form a larger exhaust channel in the event of thermal runaway of the battery cell 30. This facilitates rapid pressure relief of the battery cell 30 and reduces the risk of explosion due to thermal runaway. Furthermore, the connection 52 of the liquid injection structure 50 is sealed to the first part 41 and the second part 42 on both sides, improving the reliability and sealing of the connection between the liquid injection structure 50 and the pressure relief mechanism 40, and reducing the risk of the liquid injection structure 50 detaching and electrolyte leakage.

[0172] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: A housing having a receiving cavity, the housing including a first wall; Electrode assembly, housed within the housing; A pressure relief mechanism is disposed on the first wall. The pressure relief mechanism has a through hole that penetrates both sides of the pressure relief mechanism along the thickness direction of the first wall. The pressure relief mechanism includes a first part and a second part stacked along the thickness direction. The periphery of the first part is connected to the first wall. The liquid injection structure is provided on the pressure relief mechanism. The liquid injection structure includes a liquid injection body and a connecting part. The liquid injection body passes through the through hole, and the connecting part is connected to the periphery of the liquid injection body. The connecting part is sealed to the first part and the second part on both sides along the thickness direction, respectively.

2. The battery cell according to claim 1, characterized in that, The second part covers the surface of the connecting part on the side facing the second part.

3. The battery cell according to claim 1, characterized in that, The battery cell further includes a sealant layer, which is disposed between the connecting portion and the first portion, and / or, the sealant layer is disposed between the connecting portion and the second portion.

4. The battery cell according to claim 3, characterized in that, The sealant layer covers the connection portion, and the peripheral edge of the sealant layer extends beyond the peripheral edge of the connection portion.

5. The battery cell according to claim 1, characterized in that, Along the radial direction of the injection body, the dimension of the injection body is d, and the dimension of the connecting part is d1, where d1≥2d.

6. The battery cell according to claim 1, characterized in that, The liquid injection body has a liquid injection hole for injecting electrolyte into the receiving cavity. The liquid injection structure also includes a sealing pin that seals the liquid injection hole.

7. The battery cell according to claim 1, characterized in that, The peripheral side of the second part is connected to the first wall. The pressure relief mechanism is configured such that when the pressure inside the battery cell reaches an actuation threshold, at least a portion of the connection between the peripheral side of the second part and the first wall is separated, and at least a portion of the connection between the peripheral side of the first part and the first wall is also separated, to release the pressure inside the battery cell.

8. The battery cell according to claim 7, characterized in that, The second part is provided with reinforcing ribs, and / or the first part is provided with reinforcing ribs, and the through hole is offset from the reinforcing ribs.

9. The battery cell according to claim 1, characterized in that, The liquid injection body has a liquid injection hole, which is used to inject electrolyte into the receiving cavity; The battery cell also includes a stop portion connected to the first wall. At least a portion of the stop portion is located on the side of the injection hole facing the electrode assembly and is spaced apart from the injection hole along the thickness direction.

10. The battery cell according to claim 9, characterized in that, The stop portion includes a first stop strip and a second stop strip. The extension direction of the first stop strip intersects the extension direction of the second stop strip. A portion of the first stop strip and a portion of the second stop strip are respectively disposed opposite to the injection hole along the thickness direction.

11. The battery cell according to any one of claims 1 to 10, characterized in that, The battery cell also includes a protective component, which is attached to the side of the first wall facing away from the electrode assembly and covers the pressure relief mechanism and the liquid injection structure.

12. The battery cell according to claim 11, characterized in that, The first wall has a pressure relief hole that penetrates the first wall and includes a first hole segment, a second hole segment, and a first stepped surface. The first hole segment is located on the side of the second hole segment near the electrode assembly, and the radial dimension of the first hole segment is smaller than the radial dimension of the second hole segment. The first stepped surface connects the hole wall of the first hole segment and the hole wall of the second hole segment. The pressure relief mechanism is located within the first hole section, and the protective component is connected to the first stepped surface.

13. The battery cell according to claim 12, characterized in that, The protective element is located inside the second hole section.

14. The battery cell according to claim 12, characterized in that, Along the direction perpendicular to the thickness, the orthographic projection of the end face of the liquid injection structure on the side away from the electrode assembly is located inside the first hole segment.

15. The battery cell according to any one of claims 1 to 10, characterized in that, The first part has a serrated area, and the pressure relief mechanism is configured to open with the serrated area as the boundary when the pressure inside the battery cell reaches the actuation threshold, so as to release the pressure inside the battery cell. The injection structure is misaligned with the scoring area.

16. The battery cell according to any one of claims 1 to 10, characterized in that, The liquid injection body has a liquid injection hole for injecting electrolyte into the receiving cavity. The liquid injection hole includes a third hole segment, a fourth hole segment, and a second stepped surface. The third hole segment is located on the side of the fourth hole segment facing the electrode assembly, and the diameter of the third hole segment is smaller than the diameter of the fourth hole segment. The second stepped surface connects the inner wall of the third hole segment and the inner wall of the fourth hole segment.

17. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1 to 16.

18. An electrical appliance, characterized in that, Includes the battery device as described in claim 17, the battery device being used to provide electrical energy.

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