End cap assembly, battery cell, battery and electrical equipment

Abstract

The embodiments of the present application provide an end cap assembly, a battery cell, a battery, an electrical device, a method for manufacturing a battery cell, and an apparatus, and relate to the field of battery technology. The end cap assembly includes an end cap and a pressure relief mechanism. The pressure relief mechanism is connected to the end cap. The pressure relief mechanism is configured to: be in a first pressure relief state when the internal pressure or temperature of the battery cell is greater than or equal to a first threshold value and less than a second threshold value, so as to release the internal pressure of the battery cell; be in a second pressure relief state when the internal pressure or temperature of the battery cell is greater than or equal to a second threshold value, so as to release the internal pressure of the battery cell; the pressure relief area in the first pressure relief state is smaller than the pressure relief area in the second pressure relief state. When the internal pressure value or temperature value of the battery cell is large, the pressure can be relieved quickly, the pressure relief capacity is improved, and the internal pressure can be ensured to be constant at all times. The pressure relief mechanism does not need to reserve gas storage space, does not occupy the space inside the battery cell, and does not affect the energy density of the battery cell.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to an end cover assembly, a battery cell, a battery, an electrical device, and a method and equipment for manufacturing a battery cell. Background Art

[0002] Lithium-ion batteries have become the mainstream product of secondary batteries due to their outstanding advantages such as high energy density and good cycle performance, and are widely used in portable appliances, power vehicles, mobile phones, spacecraft and other fields.

[0003] A battery generally includes a shell, an end cap assembly and an electrode assembly. The end cap assembly is covered on the shell to provide a closed space for the electrode assembly and the electrolyte. The electric energy of the electrode assembly can be led out of the shell through the electrode terminal of the end cap assembly.

[0004] In order to ensure the safety performance of the battery, a pressure relief mechanism is generally set in the end cap assembly. When the internal pressure or temperature of the battery reaches a threshold, the pressure inside the battery can be released through the pressure relief mechanism. Whether the pressure relief mechanism can effectively release pressure directly affects the safety performance of the battery. Therefore, how to ensure the effective pressure relief ability of the pressure relief mechanism is an urgent problem to be solved in battery technology. Summary of the invention

[0005] The embodiments of the present application provide an end cap assembly, a battery cell, a battery, an electrical device, and a method and equipment for manufacturing a battery cell to improve the safety performance of the battery.

[0006] In a first aspect, an embodiment of the present application provides an end cap assembly for a battery cell, comprising an end cap and a pressure relief mechanism. The pressure relief mechanism is connected to the end cap. The pressure relief mechanism is configured to: be in a first pressure relief state when the internal pressure or temperature of the battery cell is greater than or equal to a first threshold value and less than a second threshold value, so as to release the internal pressure of the battery cell; be in a second pressure relief state when the internal pressure or temperature of the battery cell is greater than or equal to the second threshold value, so as to release the internal pressure of the battery cell. Wherein, the pressure relief area of ​​the pressure relief mechanism in the first pressure relief state is smaller than the pressure relief area of ​​the pressure relief mechanism in the second pressure relief state.

[0007] In the above technical solution, the pressure relief mechanism has two pressure relief states, which respectively match different pressures or temperatures inside the battery cell, and release pressure when the pressure or temperature inside the battery cell reaches a threshold: when the pressure or temperature inside the battery cell is greater than the first threshold and less than the second threshold, the pressure relief mechanism releases the internal pressure of the battery cell in the first pressure relief state, and when the pressure or temperature inside the battery cell is greater than the second threshold, the pressure relief mechanism releases the internal pressure of the battery cell in the second pressure relief state, and the pressure relief area in the first pressure relief state is smaller than the pressure relief area in the second pressure relief state, that is, the pressure relief rate of the second pressure relief state is greater than the pressure relief rate of the first pressure relief state, therefore, when the pressure value or temperature value inside the battery cell is large, rapid pressure relief can be achieved, and the pressure relief capacity is improved to ensure the safety performance of the battery cell. And as the pressure or temperature inside the battery cell is different, the pressure relief rate of the pressure relief mechanism is different, which can ensure that the pressure inside the battery cell is always constant. In addition, the pressure relief mechanism does not need to reserve gas storage space, that is, the pressure relief mechanism will not occupy the space inside the battery cell, avoiding the pressure relief mechanism affecting the energy density of the battery cell.

[0008] In some embodiments of the first aspect, the pressure relief mechanism includes a main body and an opening device; the main body has a pressure relief port, and the opening device is configured to open at least part of the pressure relief port when the pressure relief mechanism is in the first pressure relief state and the second pressure relief state to release the pressure inside the battery cell through the pressure relief port; wherein, in the first pressure relief state, the pressure relief area of ​​the pressure relief port is smaller than the pressure relief area of ​​the pressure relief port in the second pressure relief state.

[0009] In the above technical solution, the pressure relief mechanism releases the pressure inside the battery cell through the pressure relief port. When the pressure relief area of ​​the pressure relief port is smaller than that of the pressure relief port in the second pressure relief state in the first pressure relief state, the opening device can open the pressure relief port to different degrees according to the pressure or temperature inside the battery cell, so that the pressure relief mechanism releases pressure at different pressure relief rates, thereby ensuring that the pressure inside the battery cell is constant at all times.

[0010] In some embodiments of the first aspect of the present application, the pressure relief port includes a first pressure relief port and a second pressure relief port that are independent of each other, and when the pressure relief mechanism is in the first pressure relief state, the first pressure relief port is opened and the second pressure relief port is closed; when the pressure relief mechanism is in the second pressure relief state, both the first pressure relief port and the second pressure relief port are opened.

[0011] In the above technical solution, the pressure relief mechanism includes a first pressure relief port and a second pressure relief port which are independent of each other, thereby ensuring the structural strength of the pressure relief mechanism.

[0012] In some embodiments of the first aspect of the present application, the opening device includes a sealing member connected to the main body; the sealing member is configured to be subjected to force to open at least part of the pressure relief port when the pressure or temperature inside the battery cell is greater than or equal to the first threshold.

[0013] In the above technical solution, the sealing member is subjected to force to open at least part of the pressure relief port when the pressure or temperature inside the battery cell is greater than or equal to the first threshold value, and can return to its original state to seal the pressure relief port when the internal pressure or temperature of the battery cell is less than the first threshold value, thereby achieving pressure relief and sealing of the pressure relief mechanism, so that both pressure relief and sealing can be achieved in a timely manner.

[0014] In some embodiments of the first aspect of the present application, the opening device also includes an extrusion member, which is movably disposed on the main body; the extrusion member is configured to move relative to the main body when the pressure or temperature inside the battery cell is greater than or equal to the first threshold value, so that the sealing member is compressed by force to open at least a portion of the pressure relief port.

[0015] In the above technical solution, the extrusion piece is compressed by moving the extrusion piece so that the sealing piece can open the pressure relief port to release pressure. The setting of the extrusion piece can effectively compress the sealing piece when the pressure or temperature inside the battery cell is greater than the first threshold value, thereby opening the pressure relief port to release pressure, and the sealing piece can be evenly stressed during the compression process.

[0016] In some embodiments of the first aspect of the present application, the main body has a supporting portion, and the extrusion member is closer to the interior of the battery cell than the supporting portion; the supporting portion is configured to cooperate with the extrusion member to squeeze the sealing member when the pressure or temperature inside the battery cell is greater than or equal to the first threshold value, so that the sealing member is compressed by force to open at least part of the pressure relief port.

[0017] In the above technical solution, the abutment portion and the extrusion member cooperate to extrude the sealing member when the pressure or temperature inside the battery cell is greater than or equal to a first threshold value so that the sealing member is compressed to open at least part of the pressure relief port, and can return to its original state to seal the pressure relief port when the internal pressure or temperature of the battery cell is less than the first threshold value, thereby achieving pressure relief and sealing of the pressure relief mechanism, so that both pressure relief and sealing can be achieved in a timely manner.

[0018] In some embodiments of the first aspect of the present application, the main body further includes a limiting portion, which is arranged around the outer periphery of the abutting portion, and the limiting portion and the abutting portion jointly define an accommodating cavity, and the accommodating cavity is used to accommodate the extrusion member and the sealing member.

[0019] In the above technical solution, the limiting part and the abutting part jointly define a housing cavity for accommodating the extrusion part and the blocking part, which can prevent the blocking part and the extrusion part from being exposed to the external environment, prevent the external environment from causing damage to the blocking part and the extrusion part, and extend the service life of the blocking part and the extrusion part. In addition, the limiting part is arranged around the outer periphery of the abutting part, so the limiting part can also play a guiding role when the extrusion part moves in the housing cavity.

[0020] In some embodiments of the first aspect of the present application, there is a gap between the inner wall of the limiting portion and the outer wall of the extrusion component.

[0021] In the above technical solution, there is a gap between the inner wall of the limiting part and the outer wall of the extrusion part, so as to avoid friction between the inner wall of the limiting part and the outer wall of the extrusion part due to contact. This can not only avoid the wear of the limiting part and the extrusion part caused by the friction between the inner wall of the limiting part and the outer wall of the extrusion part, but also make the resistance to the movement of the extrusion part relative to the main body smaller, so that the extrusion part can move smoothly and compress the blocking part to open the pressure relief port to relieve pressure when the pressure or temperature inside the battery cell is greater than or equal to the first threshold value, and move smoothly and restore the blocking part to its original state to block the pressure relief port when the pressure or temperature inside the battery cell is less than the first threshold value, thereby ensuring the safety performance of the battery cell.

[0022] In some embodiments of the first aspect of the present application, the pressure relief port is provided at the limiting portion.

[0023] In the above technical solution, the pressure relief port is arranged at the limiting portion, and the pressure relief port is located on the compression path of the blocking member, so it is convenient to open.

[0024] In some embodiments of the first aspect of the present application, the body further includes a limiting structure, and the limiting structure is configured to support the extrusion member to prevent the extrusion member from moving in a direction facing the interior of the battery cell.

[0025] In the above technical solution, the limiting structure can provide support for the extrusion piece and keep the extrusion piece in a reasonable position to prevent the extrusion piece from excessively moving toward the battery cell when the pressure or temperature inside the battery cell is less than the first threshold.

[0026] In some embodiments of the first aspect of the present application, the limiting structure is a ring structure.

[0027] In the above technical solution, the limiting structure of the annular structure can provide better support for the extrusion component.

[0028] In some embodiments of the first aspect of the present application, the first pressure relief port is closer to the interior of the battery cell than the second pressure relief port.

[0029] In the above technical solution, the pressure or temperature inside the battery cell is different, and the compression amount of the sealing part is different. When the compression amount of the sealing part is small, it can only open part or all of the first pressure relief port closer to the inside of the battery cell. When the compression amount of the sealing part increases, it can completely open part or all of the first pressure relief port and the second pressure relief port farther from the inside of the battery cell, so that the pressure relief area is different in the two pressure relief states, which facilitates the pressure relief mechanism to switch between the two pressure relief states.

[0030] In some embodiments of the first aspect of the present application, the end cover has a recessed portion recessed toward the interior of the battery cell, and the recessed portion is configured to accommodate at least a portion of the pressure relief mechanism.

[0031] In the above technical solution, a recessed portion for accommodating at least part of the pressure relief mechanism is provided on the end cover, which can reduce the structural size of the battery cell and reduce the space occupied by the battery cell.

[0032] In a second aspect, an embodiment of the present application provides a battery cell, comprising a housing, an electrode assembly, and an end cap assembly provided in the embodiment of the first aspect. The housing has an opening. The electrode assembly is accommodated in the housing. The end cap is used to cover the opening.

[0033] In the above technical solution, the pressure relief mechanism of the battery cell has two pressure relief states, which respectively match different pressures or temperatures inside the battery cell, and release pressure when the pressure or temperature inside the battery cell reaches a threshold: when the pressure or temperature inside the battery cell is greater than the first threshold and less than the second threshold, the pressure relief mechanism releases the internal pressure of the battery cell in the first pressure relief state, and when the pressure or temperature inside the battery cell is greater than the second threshold, the pressure relief mechanism releases the internal pressure of the battery cell in the second pressure relief state, and the pressure relief area in the first pressure relief state is smaller than the pressure relief area in the second pressure relief state, that is, the pressure relief rate in the second pressure relief state is greater than the pressure relief rate in the first pressure relief state, therefore, when the pressure inside the battery cell is relatively large, rapid pressure relief can be achieved to ensure the safety performance of the battery cell. And as the pressure or temperature inside the battery cell is different, the pressure relief rate of the pressure relief mechanism is different, ensuring that the pressure inside the battery cell is always constant.

[0034] In a third aspect, an embodiment of the present application provides a battery, comprising a housing and a battery cell provided in the embodiment of the second aspect.

[0035] In the above technical solution, the pressure relief mechanism of the battery cell has two different pressure relief states, and can achieve rapid pressure relief when the pressure inside the battery cell is high, so as to ensure the safety performance of the battery cell, and then ensure the safety performance of the battery. And as the pressure or temperature inside the battery cell is different, the pressure relief rate of the pressure relief mechanism is different, so as to ensure that the pressure inside the battery cell is always constant.

[0036] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising the battery cell provided in the embodiment of the second aspect.

[0037] In the above technical solution, the pressure relief mechanism of the battery cell of the electrical equipment has two different pressure relief states, and can achieve rapid pressure relief when the pressure inside the battery cell is high, so as to ensure the safety performance of the battery cell, thereby ensuring the safety of electricity use. And as the pressure or temperature inside the battery cell changes, the pressure relief rate of the pressure relief mechanism is different, so as to ensure that the pressure inside the battery cell is always constant.

[0038] In a fifth aspect, some embodiments of the present application provide a method for manufacturing a battery cell, comprising: providing a housing, wherein the housing has an opening;

[0039] providing an electrode assembly;

[0040] An end cap assembly is provided, the end cap assembly comprising: an end cap; and a pressure relief mechanism connected to the end cap, the pressure relief mechanism being configured to: be in a first pressure relief state when the internal pressure or temperature of the battery cell is greater than or equal to a first threshold value and less than a second threshold value, so as to release the internal pressure of the battery cell; be in a second pressure relief state when the internal pressure or temperature of the battery cell is greater than or equal to the second threshold value, so as to release the internal pressure of the battery cell; wherein the pressure relief area of ​​the pressure relief mechanism in the first pressure relief state is smaller than the pressure relief area of ​​the pressure relief mechanism in the second pressure relief state;

[0041] The electrode assembly is accommodated in the housing and the opening is closed by the end cap assembly.

[0042] In a sixth aspect, an embodiment of the present application provides a manufacturing device for a battery cell, comprising a providing device and an installing device; the providing device is configured to: provide a shell having an opening; provide an electrode assembly; provide an end cap assembly, the end cap assembly comprising: an end cap; and a pressure relief mechanism connected to the end cap, the pressure relief mechanism being configured to: be in a first pressure relief state when the internal pressure or temperature of the battery cell is greater than or equal to a first threshold value and less than a second threshold value, so as to release the internal pressure of the battery cell; be in a second pressure relief state when the internal pressure or temperature of the battery cell is greater than or equal to the second threshold value, so as to release the internal pressure of the battery cell; wherein the pressure relief area of ​​the pressure relief mechanism in the first pressure relief state is smaller than the pressure relief area of ​​the pressure relief mechanism in the second pressure relief state; the installing device is configured to accommodate the electrode assembly in the shell and close the opening through the end cap assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without paying creative work.

[0044] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0045] Figure 2 A schematic diagram of the structure of a battery provided in some embodiments of the present application;

[0046] Figure 3 An exploded view of a battery cell provided for some embodiments of the present application;

[0047] Figure 4 An exploded view of an end cap assembly provided for some embodiments of the present application;

[0048] Figure 5 A schematic diagram of a pressure relief mechanism is provided for some embodiments of the present application;

[0049] Figure 6 An exploded diagram of a pressure relief mechanism is provided for some embodiments of the present application;

[0050] Figure 7 A cross-sectional view of a battery cell from a first perspective provided in some embodiments of the present application;

[0051] Figure 8 for Figure 7 A magnified view at position I;

[0052] Fig. 9 A cross-sectional view of a battery cell from a second perspective provided in some embodiments of the present application;

[0053] Fig.10 for Fig. 9 The enlarged view of II in the middle;

[0054] Fig.11 A schematic diagram of the structure of an end cap assembly without an extrusion member provided in some other embodiments of the present application;

[0055] Fig.12 A schematic diagram of the structure of an end cover assembly without a limiting structure provided in other embodiments of the present application;

[0056] Fig.13 A schematic diagram of a structure in which a blocking member is a ring structure is provided in some other embodiments of the present application;

[0057] Fig.14 for Fig.13 Enlarged view of position III in the middle;

[0058] Fig.15 A flowchart of a method for manufacturing a battery cell provided in some embodiments of the present application;

[0059] Fig.16 A structural block diagram of a battery cell manufacturing device provided in some embodiments of the present application.

[0060] Marking description: 1000-vehicle; 100-battery; 10-box; 11-accommodation space; 12-first part; 13-second part; 20-battery cell; 21-housing; 211-opening; 22-electrode assembly; 221-positive electrode ear; 222-negative electrode ear; 23-end cover assembly; 231-first electrode terminal; 232-second electrode terminal; 233-end cover; 2331-exhaust hole; 2332-depression; 23321-side wall; 23322-bottom wall; 23323-support part; 234-pressure relief mechanism; 2341-body; 23411-pressure relief port; 23412-first pressure relief port; 23413-second pressure relief port; 23414-resting portion; 23415-limiting portion; 23416-limiting structure; 23417-connecting portion; 2342-opening device; 23421-blocking member; 23422-extrusion member; 235-accommodating chamber; 236-gap; 237-sealing structure; 24-first adapter; 25-second adapter; 200-controller; 300-motor; 2000-battery cell manufacturing equipment; 2100-providing device; 2200-installing device; A-first direction; B-second direction; C-third direction. DETAILED DESCRIPTION

[0061] The following detailed description and drawings of the embodiments of the present application are used to illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0062] In the description of the present application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating the orientation or positional relationship, are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0063] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0064] The term "plurality" used in the present application refers to two or more (including two).

[0065] In the present application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries or magnesium-ion batteries, etc., and the embodiments of the present application do not limit this. Battery cells may be cylindrical, flat, rectangular or other shapes, etc., and the embodiments of the present application do not limit this. Battery cells are generally divided into three types according to the packaging method: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of the present application do not limit this.

[0066] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module or a battery pack. The battery generally includes a box for encapsulating one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

[0067] The battery cell includes an electrode assembly and an electrolyte. The electrode assembly is composed of a positive electrode sheet, a negative electrode sheet and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode collector. The positive electrode collector not coated with the positive electrode active material layer protrudes from the positive electrode collector coated with the positive electrode active material layer. The positive electrode collector not coated with the positive electrode active material layer serves as the positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode collector. The negative electrode collector not coated with the negative electrode active material layer protrudes from the negative electrode collector coated with the negative electrode active material layer. The negative electrode collector not coated with the negative electrode active material layer serves as the negative electrode tab. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon or silicon, etc. In order to ensure that a large current can pass without melting, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together. The material of the isolation film may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly may be a winding structure or a laminated structure, and the embodiments of the present application are not limited thereto.

[0068] The development of battery technology must take into account many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, battery safety must also be considered.

[0069] For battery cells, the main safety hazards come from the charging and discharging process, as well as the appropriate ambient temperature design. In order to effectively avoid unnecessary losses, there are generally three protection measures for battery cells. Specifically, the protection measures include at least switching elements, selecting appropriate isolation membrane materials, and pressure relief mechanisms. Switching elements refer to elements that can stop the battery from charging or discharging when the temperature or resistance inside the battery cell reaches a certain threshold. The isolation membrane is used to isolate the positive and negative electrodes. When the temperature rises to a certain value, it can automatically dissolve the micron-level (even nano-level) micropores attached to it, so that metal ions cannot pass through the isolation membrane, terminating the internal reaction of the battery cell.

[0070] The pressure relief mechanism refers to an element or component that is activated to release the internal pressure or temperature of the battery cell when the internal pressure or temperature reaches a predetermined threshold. The threshold design varies according to different design requirements. The threshold may depend on one or more materials of the positive electrode sheet, negative electrode sheet, electrolyte and separator in the battery cell.

[0071] The "actuation" mentioned in this application means that the pressure relief mechanism is in action or activated to a certain state, so that the internal pressure and temperature of the battery cell can be released. The action produced by the pressure relief mechanism may include but is not limited to: at least a part of the pressure relief mechanism is ruptured, broken, torn or opened, etc. When the pressure relief mechanism is actuated, the high-temperature and high-pressure substances inside the battery cell will be discharged from the actuated part as emissions. In this way, the pressure and temperature of the battery cell can be relieved under controllable pressure or temperature, thereby avoiding potential more serious accidents.

[0072] The emissions from the battery cells mentioned in this application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode sheets, fragments of the isolation membrane, high-temperature and high-pressure gas produced by the reaction, flames, and the like.

[0073] The pressure relief mechanism on the battery cell has an important impact on the safety of the battery. For example, when a short circuit or overcharge occurs, thermal runaway may occur inside the battery cell, causing a sudden increase in pressure or temperature. In this case, the pressure relief mechanism can be activated to release the internal pressure and temperature to prevent the battery cell from exploding or catching fire.

[0074] The inventors found that in battery cells, the pressure relief mechanism generally uses an explosion-proof valve. The gas inside the battery cell acts on the explosion-proof valve for a long time, causing stress fatigue in the explosion-proof valve, shortening the service life of the explosion-proof valve. In addition, in order to analyze the composition of the battery cell emissions, a storage space is reserved on the explosion-proof valve. The storage space can collect the emissions inside the battery cell for analysis, but the storage space will occupy the space inside the battery cell, thereby affecting the energy density of the battery cell.

[0075] In view of this, the embodiment of the present application provides a technical solution to replace the existing explosion-proof valve on the battery cell, which not only has two pressure relief states, but also can achieve rapid pressure relief when the pressure value or temperature value inside the battery cell is large, thereby improving the pressure relief capacity and ensuring the safety performance of the battery cell. And as the pressure or temperature inside the battery cell is different, the pressure relief rate of the pressure relief mechanism is different, which can ensure that the pressure inside the battery cell is constant at all times. In addition, the pressure relief mechanism does not need to reserve gas storage space, that is, the pressure relief mechanism will not occupy the space inside the battery cell, avoiding the pressure relief mechanism affecting the energy density of the battery cell.

[0076] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical equipment using batteries.

[0077] Electrical equipment may be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, electric tools, and the like. Vehicles may be fuel vehicles, gas vehicles, or new energy vehicles, and new energy vehicles may be pure electric vehicles, hybrid vehicles, or extended-range vehicles, and the like; spacecraft include airplanes, rockets, space shuttles, and spacecraft, and the like; electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like; electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, and the like. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical equipment.

[0078] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0079] Please refer to Figure 1 , Figure 1 The schematic diagram of the structure of the vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 is provided with a battery 100 inside, and the battery 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000, for example, the battery 100 can be used as an operating power source of the vehicle 1000.

[0080] The vehicle 1000 may further include a controller 200 and a motor 300 , wherein the controller 200 is used to control the battery 100 to supply power to the motor 300 , for example, to meet the power requirements of starting, navigating, and driving the vehicle 1000 .

[0081] In some embodiments of the present application, the battery 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0082] Please refer to Figure 2 , Figure 2 The schematic diagram of the structure of the battery 100 provided in some embodiments of the present application. The battery 100 includes a box body 10 and a battery cell 20 , and the battery cell 20 is accommodated in the box body 10 .

[0083] The box body 10 is used to provide a storage space 11 for the battery cell 20. In some embodiments, the box body 10 may include a first portion 12 and a second portion 13, and the first portion 12 and the second portion 13 cover each other to define the storage space 11 for accommodating the battery cell 20. Of course, the connection between the first portion 12 and the second portion 13 can be sealed by a sealing member (not shown in the figure), and the sealing member can be a sealing ring, a sealant, etc.

[0084] The first part 12 and the second part 13 can be in various shapes, such as a cuboid, a cylinder, etc. The first part 12 can be a hollow structure with one side open, and the second part 13 can also be a hollow structure with one side open. The open side of the second part 13 covers the open side of the first part 12, thus forming a box body 10 with a receiving space 11. Of course, if Figure 2 As shown, the first part 12 may be a hollow structure with one side open, and the second part 13 may be a plate-like structure. The second part 13 covers the open side of the first part 12 to form a box body 10 with an accommodating space 11.

[0085] In the battery 100, there can be one or more battery cells 20. If there are more than one battery cell 20, the battery cells 20 can be connected in series, in parallel or in a mixed connection. A mixed connection means that the battery cells 20 are connected in series and in parallel. The battery cells 20 can be directly connected in series, in parallel or in a mixed connection, and then the whole formed by the battery cells 20 can be accommodated in the box 10; of course, the battery cells 20 can be connected in series, in parallel or in a mixed connection to form a battery module, and then the battery modules can be connected in series, in parallel or in a mixed connection to form a whole, and then accommodated in the box 10. The battery cell 20 can be cylindrical, flat, rectangular or in other shapes. Figure 2 The example shows that the battery cell 20 is a rectangular parallelepiped.

[0086] In some embodiments, the battery 100 may further include a busbar component (not shown), and the multiple battery cells 20 may be electrically connected via the busbar component to achieve series connection, parallel connection, or mixed connection of the multiple battery cells 20 .

[0087] Please refer to Figure 3 , Figure 3 An exploded view of a battery cell 20 provided in some embodiments of the present application. The battery cell 20 may include a housing 21, an electrode assembly 22, and an end cap assembly 23. The housing 21 has an opening 211, the electrode assembly 22 is accommodated in the housing 21, and the end cap assembly 23 is used to cover the opening 211.

[0088] The shell 21 can be in various shapes, such as a cylinder, a cuboid, etc. The shape of the shell 21 can be determined according to the specific shape of the electrode assembly 22. For example, if the electrode assembly 22 is a cylindrical structure, the shell 21 can be selected as a cylindrical structure; if the electrode assembly 22 is a cuboid structure, the shell 21 can be selected as a cuboid structure. Figure 3 The case where the housing 21 is a rectangular parallelepiped and the electrode assembly 22 is a flat body is exemplified.

[0089] The shell 21 may also be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0090] The electrode assembly 22 may include a positive electrode sheet (not shown), a negative electrode sheet (not shown) and a separator (not shown). The electrode assembly 22 may be a wound structure formed by winding the positive electrode sheet, the separator and the negative electrode sheet, or a stacked structure formed by stacking the positive electrode sheet, the separator and the negative electrode sheet. The electrode assembly 22 also includes a positive electrode tab 221 and a negative electrode tab 222. The positive electrode tab 221 may be a positive electrode current collector not coated with a positive electrode active material layer in the positive electrode sheet, and the negative electrode tab 222 may be a negative electrode current collector not coated with a negative electrode active material layer in the negative electrode sheet.

[0091] The end cap assembly 23 is used to seal the opening 211 of the housing 21 to form a housing (not shown), which is used to accommodate the electrode assembly 22. The housing is also used to accommodate an electrolyte, such as an electrolyte. The end cap assembly 23 is a component for outputting the electrical energy of the electrode assembly 22, and the electrode terminal in the end cap assembly 23 is used to be electrically connected to the electrode assembly 22. In some embodiments, the electrode terminal and the tab are electrically connected through an adapter. Figure 3 As shown, the end cap assembly 23 includes a first electrode terminal 231 and a second electrode terminal 232 . The first electrode terminal 231 is electrically connected to the positive electrode tab 221 through the first adapter 24 , and the second electrode terminal 232 is electrically connected to the negative electrode tab 222 through the second adapter 25 .

[0092] It should be noted that the opening 211 of the housing 21 may be one or two. Figure 3 As shown, if there is one opening 211 of the housing 21, there can also be one end cap assembly 23, and two electrode terminals can be provided in the end cap assembly 23, and the two electrode terminals are respectively used to electrically connect to the positive pole ear 221 and the negative pole ear 222 of the electrode assembly 22, and the two electrode terminals in the end cap assembly 23 are respectively a positive electrode terminal and a negative electrode terminal. If there are two openings 211 of the housing 21, for example, the two openings 211 are provided on opposite sides of the housing 21, there can also be two end cap assemblies 23, and the two end cap assemblies 23 are respectively covered at the two openings 211 of the housing 21. In this case, the electrode terminal in one end cap assembly 23 can be a positive electrode terminal, which is used to electrically connect to the positive pole ear 221 of the electrode assembly 22; and the electrode terminal in the other end cap assembly 23 can be a negative electrode terminal, which is used to electrically connect to the negative pole ear 222 of the electrode assembly 22.

[0093] Please refer to Figure 4 , Figure 5 . Figure 4 An exploded view of an end cap assembly 23 provided in some embodiments of the present application. Figure 5A schematic diagram of the structure of the pressure relief mechanism 234 is provided for some embodiments of the present application. The end cover assembly 23 includes an end cover 233 and a pressure relief mechanism 234 .

[0094] The end cover 233 is provided with an exhaust hole 2331, and the pressure relief mechanism 234 is connected to the end cover 233 and covers the exhaust hole 2331. The exhaust inside the battery cell 20 can pass through the exhaust hole 2331 and be discharged from the battery cell 20 during the pressure relief process of the pressure relief mechanism 234.

[0095] In some embodiments, the pressure relief mechanism 234 is disposed between the first electrode terminal 231 and the second electrode terminal 232 .

[0096] The pressure relief mechanism 234 is configured to be in a first pressure relief state when the internal pressure or temperature of the battery cell 20 is greater than or equal to a first threshold value and less than a second threshold value, so as to release the internal pressure of the battery cell 20; and to be in a second pressure relief state when the internal pressure or temperature of the battery cell 20 is greater than or equal to a second threshold value, so as to release the internal pressure of the battery cell 20; wherein the pressure relief area of ​​the pressure relief mechanism 234 in the first pressure relief state is smaller than the pressure relief area of ​​the pressure relief mechanism 234 in the second pressure relief state.

[0097] The pressure relief mechanism 234 is further configured to be in a blocked state when the pressure or temperature inside the battery cell 20 is less than a first threshold value, so as to release the pressure inside the battery cell 20 .

[0098] The pressure relief mechanism 234 has two pressure relief states, which respectively match different pressures or temperatures inside the battery cell 20, and release pressure when the pressure or temperature inside the battery cell 20 reaches a threshold: when the pressure or temperature inside the battery cell 20 is greater than the first threshold and less than the second threshold, the pressure relief mechanism 234 releases the internal pressure of the battery cell 20 in the first pressure relief state, and when the pressure or temperature inside the battery cell 20 is greater than the second threshold, the pressure relief mechanism 234 releases the internal pressure of the battery cell 20 in the second pressure relief state, and the pressure relief area in the first pressure relief state is smaller than the pressure relief area in the second pressure relief state, that is, the pressure relief rate in the second pressure relief state is greater than the pressure relief rate in the first pressure relief state, therefore, when the pressure value or temperature value inside the battery cell 20 is large, rapid pressure relief can be achieved, and the pressure relief capacity is improved to ensure the safety performance of the battery cell 20. And as the pressure or temperature inside the battery cell 20 is different, the pressure relief rate of the pressure relief mechanism 234 is different, which can ensure that the pressure inside the battery cell 20 is constant at all times. In addition, the pressure relief mechanism 234 does not need to reserve a gas storage space, that is, the pressure relief mechanism 234 does not occupy the space inside the battery cell 20, so as to avoid the pressure relief mechanism 234 affecting the energy density of the battery cell 20.

[0099] After thermal runaway, the internal temperature of the battery cell 20 will rise and gas will be released, and both the temperature rise and the gas release will cause the internal pressure of the battery cell 20 to rise. The pressure relief mechanism 234 can be actuated according to the change of the temperature value or pressure value inside the battery cell 20 to release the pressure inside the battery cell 20.

[0100] In some embodiments, the pressure relief mechanism 234 is actuated according to the change of the temperature value inside the battery cell 20 to release the pressure inside the battery cell 20. For example, the pressure relief mechanism 234 includes a pressure relief portion (not shown in the figure), the pressure relief portion is a first pressure relief portion (not shown in the figure) made of a first material and a second pressure relief portion (not shown in the figure) made of a second material, the heat resistance of the first material is lower than that of the second material, the first pressure relief portion and the second pressure relief portion correspond to two pressure relief states respectively, when the temperature inside the battery cell 20 is greater than the first threshold value and less than the second threshold value, the first material is thermally melted to form a first through hole (not shown in the figure) in the first pressure relief portion, and the pressure relief mechanism 234 is in the first pressure relief state and releases the pressure and emissions inside the battery cell 20 through the first through hole. When the temperature inside the battery cell 20 is greater than the second threshold value, the first material is thermally melted to form a first through hole in the first pressure relief portion and the second material is thermally melted to form a second through hole (not shown in the figure), and the pressure relief mechanism 234 is in the second pressure relief state and releases the pressure and emissions inside the battery cell 20 through the first through hole and the second through hole.

[0101] In some embodiments, the pressure relief mechanism 234 is actuated to relieve the pressure inside the battery cell 20 according to the increase in temperature inside the battery cell 20 and the increase in pressure value inside the battery cell 20 caused by the released gas.

[0102] like Figure 4 , Figure 5 As shown, in some embodiments, the pressure relief mechanism 234 includes a body 2341 and an opening device 2342. The body 2341 has a pressure relief port 23411, and the opening device 2342 is configured to open at least a portion of the pressure relief port 23411 when the pressure relief mechanism 234 is in a first pressure relief state and a second pressure relief state, so as to release the pressure inside the battery cell 20 through the pressure relief port 23411; wherein, in the first pressure relief state, the pressure relief area of ​​the pressure relief port 23411 is smaller than the pressure relief area of ​​the pressure relief port 23411 in the second pressure relief state.

[0103] The pressure relief mechanism 234 releases the pressure inside the battery cell 20 through the pressure relief port 23411. When in the first pressure relief state, the pressure relief area of ​​the pressure relief port 23411 is smaller than the pressure relief area of ​​the pressure relief port 23411 in the second pressure relief state. The opening device 2342 can open the pressure relief port 23411 to different degrees according to the pressure or temperature inside the battery cell 20, so that the pressure relief mechanism 234 releases pressure at different pressure relief rates, thereby ensuring that the pressure inside the battery cell 20 is constant at all times.

[0104] In some embodiments, there is one pressure relief port 23411. When the pressure relief mechanism 234 is in a blocked state, the pressure or temperature inside the battery cell 20 is less than the first threshold, and the pressure relief port 23411 is completely blocked by the opening device 2342. When the pressure or temperature inside the battery cell 20 is greater than or equal to the first threshold, the opening device 2342 opens at least part of the pressure relief port 23411, and the pressure inside the battery cell 20 is released through the pressure relief port 23411. When the pressure or temperature inside the battery cell 20 is greater than or equal to the first threshold and less than the second threshold, the area of ​​the pressure relief port 23411 opened by the opening device 2342 is the first area, and the pressure relief area is the first area. When the pressure or temperature inside the battery cell 20 is greater than the second threshold, the area of ​​the pressure relief port 23411 opened by the opening device 2342 is the second area, and the pressure relief area is the second area. The second area is a portion of the first area that is opened further, so that the first area is smaller than the second area.

[0105] like Figure 5 As shown, in some embodiments, the pressure relief port 23411 includes a first pressure relief port 23412 and a second pressure relief port 23413 that are independent of each other. When the pressure relief mechanism 234 is in the first pressure relief state, the first pressure relief port 23412 is opened and the second pressure relief port 23413 is closed; when the pressure relief mechanism 234 is in the second pressure relief state, both the first pressure relief port 23412 and the second pressure relief port 23413 are opened. The pressure relief mechanism 234 includes a first pressure relief port 23412 and a second pressure relief port 23413 that are independent of each other, which can avoid forming a large area of ​​the pressure relief port 23411 at the same position of the body 2341, thereby ensuring the structural strength of the pressure relief mechanism 234.

[0106] It should be noted that when the pressure relief mechanism 234 is in the first pressure relief state, the first pressure relief port 23412 may be partially open or fully open. When the pressure relief mechanism 234 is in the second pressure relief state, the first pressure relief port 23412 is fully open, and the second pressure relief port 23413 may be partially open or fully open.

[0107] The area of ​​the first pressure relief port 23412 and the area of ​​the second pressure relief port 23413 may be equal or unequal. In some embodiments, the area of ​​the first pressure relief port 23412 is smaller than the area of ​​the second pressure relief port 23413.

[0108] like Figure 5 As shown, the first pressure relief port 23412 is closer to the interior of the battery cell 20 than the second pressure relief port 23413. In the third direction C, the distance between the first pressure relief port 23412 and the second pressure relief port 23413 is H.

[0109] The number of the first pressure relief openings 23412 can be one or more, and the number of the second pressure relief openings 23413 can be one or more. Figure 5 As shown, there are two first pressure relief ports 23412, which are arranged opposite to each other in the first direction A, and there are two second pressure relief ports 23413, which are arranged opposite to each other in the second direction B. The first direction A, the second direction B and the third direction C are perpendicular to each other, wherein the third direction C is consistent with the central axis direction of the exhaust hole 2331. This structure allows the first pressure relief ports 23412 and the second pressure relief ports 23413 to be evenly distributed on the body 2341, which can avoid reducing the structural strength of the body 2341 due to the concentrated distribution of the first pressure relief ports 23412 and the second pressure relief ports 23413.

[0110] The first pressure relief port 23412 and the second pressure relief port 23413 may also be arranged in other ways. In some embodiments, the two first pressure relief ports 23412 are arranged relatively to each other along the first direction A, and the two second pressure relief ports 23413 are arranged relatively to each other along the first direction A. The first pressure relief port 23412 is closer to the interior of the battery cell 20 than the second pressure relief port 23413.

[0111] Please refer to Figure 6 , Figure 6 An exploded view of the pressure relief mechanism 234 is provided for some embodiments of the present application. The opening device 2342 includes a blocking member 23421, which is connected to the body 2341. The blocking member 23421 is configured to be subjected to force to open at least part of the pressure relief port 23411 when the pressure or temperature inside the battery cell 20 is greater than or equal to a first threshold.

[0112] In some embodiments, the blocking member 23421 is movably disposed on the body 2341. When the pressure or temperature inside the battery cell 20 is greater than or equal to the first threshold, due to the pressure difference between the inside and outside of the battery cell 20, the gas inside the battery cell 20 drives the blocking member 23421 to move in the forward direction to open the pressure relief port 23411. In this structure, when the pressure or temperature inside the battery 100 is less than the first threshold, other power elements are required to drive the blocking member 23421 to move in the reverse direction to block the pressure relief port 23411, so that the pressure relief mechanism 234 is in a blocked state.

[0113] In some embodiments, one end of the plugging member 23421 is fixed relative to the body 2341, and the plugging member 23421 opens or blocks the pressure relief port 23411 in a manner of elastic deformation. The plugging member 23421 is configured to be compressed when the pressure or temperature inside the battery cell 20 is greater than or equal to the first threshold value to open at least part of the pressure relief port 23411, and to return to its original state to block the pressure relief port 23411 when the pressure inside the battery cell 20 is less than the first threshold value. It can be understood that the plugging member 23421 is an elastic member, which can generate different deformation amounts under the force generated by the gas inside the battery cell 20 according to different pressure values ​​or temperature values ​​inside the battery cell 20.

[0114] When the pressure or temperature inside the battery cell 20 is greater than or equal to the first threshold, the plugging member 23421 is compressed to open at least part of the pressure relief port 23411, and when the pressure or temperature inside the battery cell 20 is less than the first threshold, it can be restored to its original state to block the pressure relief port 23411, thereby achieving pressure relief and blocking of the pressure relief mechanism 234, so that both pressure relief and blocking can be achieved in time. In addition, the elastic plugging member 23421 can effectively prevent the gas inside the battery cell 20 from acting on the pressure relief mechanism 234 for a long time, causing stress fatigue of the pressure relief mechanism, thereby extending the service life of the pressure relief mechanism 234.

[0115] In some embodiments, the blocking member 23421 is configured to be compressed when the pressure or temperature inside the battery cell 20 is greater than or equal to the first threshold value to open at least part of the pressure relief port 23411, and the first pressure relief port 23412 is closer to the inside of the battery cell 20 than the second pressure relief port 23413. When the pressure or temperature inside the battery cell 20 is different, the compression amount of the blocking member 23421 is different. When the compression amount of the blocking member 23421 is small, only part or all of the first pressure relief port 23412 closer to the inside of the battery cell 20 can be opened. When the compression amount of the blocking member 23421 increases, the first pressure relief port 23412 and part or all of the second pressure relief port 23413 farther from the inside of the battery cell 20 can be fully opened, so that the pressure relief area is different under the two pressure relief states, which facilitates the pressure relief mechanism 234 to switch between the two pressure relief states.

[0116] Please refer to Figure 7 , Figure 8 , Figure 7 A cross-sectional view of a battery cell 20 from a first perspective provided in some embodiments of the present application, Figure 8 for Figure 7 Enlarged view at I. The body 2341 has a receiving cavity 235, and the sealing member 23421 is filled in the receiving cavity 235. When the pressure or temperature inside the battery cell 20 is greater than or equal to the first threshold, the gas inside the battery cell 20 provides an extrusion force to the sealing member 23421, and the sealing member 23421 interacts with the cavity wall of the receiving cavity 235 and is compressed to open the pressure relief port 23411 to relieve pressure.

[0117] In some embodiments, the opening device 2342 further includes an extrusion piece 23422, which is movably disposed on the body 2341; the extrusion piece 23422 is configured to move relative to the body 2341 when the pressure or temperature inside the battery cell 20 is greater than or equal to a first threshold value, so that the blocking piece 23421 is compressed by force to open at least part of the pressure relief port 23411. The extrusion piece 23422 is compressed by the movement of the extrusion piece 23422 so that the blocking piece 23421 can open the pressure relief port 23411 to release pressure. The arrangement of the extrusion piece 23422 can effectively compress the blocking piece 23421 when the pressure or temperature inside the battery cell 20 is greater than the first threshold value, so as to open the pressure relief port 23411 to release pressure, and the blocking piece 23421 is subjected to uniform force during the compression process.

[0118] In some embodiments, Figure 8 As shown, the extrusion member 23422 is a disc structure. In other embodiments, the extrusion member 23422 can also be a regular or irregular structure such as a polygon.

[0119] In some embodiments, the extrusion 23422 can be made of metal plates such as steel plates, copper plates, or other materials with a certain heat resistance.

[0120] like Figure 8 As shown, in some embodiments, the main body 2341 has a supporting portion 23414, and the extrusion piece 23422 is closer to the interior of the battery cell 20 than the supporting portion 23414; the supporting portion 23414 is configured to cooperate with the extrusion piece 23422 to extrude the sealing piece 23421 when the pressure or temperature inside the battery cell 20 is greater than or equal to a first threshold value, so that the sealing piece 23421 is compressed by force to open at least a portion of the pressure relief port 23411. Figure 8 The direction of the arrow shown at the middle exhaust hole 2331 is the direction of the force applied by the gas inside the battery cell 20 to push the extruding member 23422 to move.

[0121] The extrusion member 23422 and the abutment portion 23414 are arranged relative to each other in the third direction C. The abutment portion 23414 is arranged on the side of the sealing member 23421 away from the interior of the battery cell 20 and is always pressed against the sealing member 23421. As the pressure value or temperature value inside the battery cell 20 changes, the pressing force between the sealing member 23421 and the abutment portion 23414 also changes.

[0122] When the pressure or temperature inside the battery cell 20 is greater than or equal to a first threshold, the abutment portion 23414 and the extrusion piece 23422 cooperate to extrude the sealing piece 23421 so that the sealing piece 23421 is compressed to open at least a portion of the pressure relief port 23411. When the internal pressure or temperature of the battery cell 20 is less than the first threshold, the abutment portion 23414 and the extrusion piece 23422 can return to their original state to seal the pressure relief port 23411, thereby achieving pressure relief and sealing of the pressure relief mechanism 234, so that both pressure relief and sealing can be achieved in a timely manner.

[0123] In some embodiments, Figure 8 As shown, the abutting portion 23414 is a disc structure, and the third direction C is consistent with the axial direction of the abutting portion 23414. In other embodiments, the abutting portion 23414 may also be a regular or irregular structure such as a polygon.

[0124] Please refer to Fig. 9 , Fig.10 , Fig. 9 A cross-sectional view of a battery cell 20 from a second perspective provided in some embodiments of the present application, Fig.10 for Fig. 9 Enlarged view of II in the middle. In some embodiments, the body 2341 also includes a limiting portion 23415, which is arranged around the outer periphery of the abutting portion 23414. The limiting portion 23415 and the abutting portion 23414 jointly define a receiving cavity 235, and the receiving cavity 235 is used to accommodate the extrusion member 23422 and the blocking member 23421. Since the limiting portion 23415 is arranged around the outer periphery of the abutting portion 23414, the abutting portion 23414 and the limiting portion 23415 jointly define receiving cavities 235 of different shapes according to the different shapes of the abutting portion 23414. For example, when the abutting portion 23414 is a disc structure, the limiting portion 23415 is a cylindrical structure, and the limiting portion 23415 and the abutting portion 23414 jointly define a cylindrical receiving cavity 235. Fig.10 The direction of the arrow shown at the middle exhaust hole 2331 is the direction of the force applied by the gas inside the battery cell 20 to push the extruding member 23422 to move.

[0125] In some embodiments, the pressure relief port 23411 is disposed at the limiting portion 23415 , and the pressure relief port 23411 is located on the compression path of the blocking member 23421 , which is convenient for opening.

[0126] When the pressure relief mechanism 234 is in a blocked state, the blocking piece 23421 fills the accommodating space 11, and the blocking piece 23421 is pressed against the inner wall of the limiting portion 23415 and has a certain extrusion force to block the pressure relief port 23411. There may be or no extrusion force between the blocking piece 23421 and the abutting portion 23414, and between the blocking piece 23421 and the extrusion piece 23422.

[0127] The limiting portion 23415 and the abutting portion 23414 together define a housing cavity 235 for housing the extrusion member 23422 and the blocking member 23421, which can prevent the blocking member 23421 and the extrusion member 23422 from being exposed to the external environment, prevent the external environment from causing damage to the blocking member 23421 and the extrusion member 23422, and extend the service life of the blocking member 23421 and the extrusion member 23422. In addition, the limiting portion 23415 is arranged around the outer periphery of the abutting portion 23414, so the limiting portion 23415 can also play a guiding role when the extrusion member 23422 moves in the housing cavity 235.

[0128] like Fig.10 As shown, in some embodiments, there is a gap 236 between the inner wall of the limiting portion 23415 and the outer wall of the extrusion piece 23422 to avoid friction between the inner wall of the limiting portion 23415 and the outer wall of the extrusion piece 23422 due to contact. This can not only avoid the wear of the limiting portion 23415 and the extrusion piece 23422 caused by the friction between the inner wall of the limiting portion 23415 and the outer wall of the extrusion piece 23422, but also make the resistance of the extrusion piece 23422 to move relative to the body 2341 smaller, so that the extrusion piece 23422 can move smoothly and compress the blocking piece 23421 to open the pressure relief port 23411 for pressure relief when the pressure or temperature inside the battery cell 20 is greater than or equal to the first threshold value, and move smoothly and restore the blocking piece 23421 to its original state to block the pressure relief port 23411 when the pressure or temperature inside the battery cell 20 is less than the first threshold value, thereby ensuring the safety performance of the battery cell 20.

[0129] Of course, according to actual needs, in some embodiments, the inner wall of the limiting portion 23415 can contact the outer wall of the extrusion piece 23422 to prevent the extrusion piece 23422 from shaking radially along the accommodating cavity 235 .

[0130] In some embodiments, the body 2341 further includes a limiting structure 23416 , which is configured to support the extrusion piece 23422 to prevent the extrusion piece 23422 from moving in a direction facing the inside of the battery cell 20 .

[0131] The limiting structure 23416 is connected to one end of the limiting portion 23415 away from the abutting portion 23414 and extends toward the center of the accommodating cavity 235. When the pressure relief mechanism 234 is in the blocking state, the limiting structure 23416 supports the extruding member 23422 on the side away from the battery cell 20. In fact, the limiting structure 23416 supports the blocking member 23421 and the extruding member 23422 at the same time. When the battery cell 20 is in the first pressure relief state and the second pressure relief state, the extruding member 23422 is separated from the limiting structure 23416 under the action of the gas inside the battery cell 20, so as to cooperate with the abutting portion 23414 to extrude the blocking member 23421.

[0132] The limiting structure 23416 can provide support for the extrusion piece 23422 and keep the extrusion piece 23422 in a reasonable position to prevent the extrusion piece 23422 from excessively moving toward the direction facing the battery cell 20 when the pressure or temperature inside the battery cell 20 is less than the first threshold.

[0133] In some embodiments, the extrusion member 23422 can be detachably connected to the limiting structure 23416, for example, the extrusion member 23422 can be detachably connected to the limiting structure 23416 via a riveted structure.

[0134] In some embodiments, the limiting structure 23416 includes a plurality of limiting blocks arranged at intervals along the inner wall of the limiting portion 23415 in the circumferential direction, and each limiting block extends along the radial direction of the accommodating cavity 235 toward the central axis of the accommodating cavity 235. The weight of the pressure relief mechanism 234 can be reduced.

[0135] In some embodiments, the limiting structure 23416 is an annular structure, and the limiting structure 23416 with an annular structure can provide better support for the extrusion piece 23422 .

[0136] Please refer to Fig.11 , Fig.11 Schematic diagram of the structure of the end cap assembly 23 without the extrusion piece 23422 provided in other embodiments of the present application. In some embodiments, the opening device 2342 may also be provided without the extrusion piece 23422, and the gas inside the battery cell 20 directly acts on the side of the blocking piece 23421 facing the inside of the battery cell 20. Fig.11 The direction of the arrow shown at the middle exhaust hole 2331 is the direction of the force applied by the gas inside the battery cell 20 to compress the sealing member 23421 .

[0137] like Fig.11 As shown, in some embodiments, the pressure relief mechanism 234 does not include the extrusion piece 23422 . When the pressure relief mechanism 234 is in a blocked state, the limiting structure 23416 supports the blocking piece 23421 to prevent the blocking piece 23421 from escaping from the accommodating cavity 235 and entering the interior of the battery cell 20 .

[0138] Please refer to Fig.12 , Fig.12 Schematic diagram of the structure of the end cap assembly 23 provided in other embodiments of the present application without the limiting structure 23416. In other embodiments, the body 2341 may also not be provided with the limiting structure 23416, and the end cap 233 supports the extrusion member 23422 or the blocking member 23421. When the pressure relief mechanism 234 is in the blocking state, the side of the end cap 233 facing away from the inside of the battery cell 20 supports the extrusion member 23422 or the blocking member 23421. Fig.12 Schematic diagram of the structure of the end cover 233 supporting the extrusion member 23422 is shown in FIG. Fig.12 The direction of the arrow shown at the middle exhaust hole 2331 is the direction of the force applied by the gas inside the battery cell 20 to push the extruding member 23422 to move.

[0139] like Fig.12 As shown, in some embodiments, the blocking member 23421 is a solid sealing gasket, and the blocking member 23421 fills the portion of the accommodating cavity 235 between the extruding member 23422 and the abutting portion 23414. The solid blocking member 23421 can provide a stable abutting force along the inner wall of the radial limiting portion 23415 of the accommodating cavity 235, so that when the pressure or temperature inside the battery cell 20 is less than the first threshold, the blocking member 23421 plays a good role in blocking the pressure relief port 23411.

[0140] Please refer to Fig.13 , Fig.13 A schematic diagram of a structure in which the blocking member 23421 is an annular structure is provided in other embodiments of the present application. In some embodiments, the blocking member 23421 can also be an annular structure, such as a sealing ring. This can reduce the weight of the pressure relief mechanism 234, thereby reducing the weight of the battery cell 20. Fig.13 The direction of the arrow shown at the middle exhaust hole 2331 is the direction of the force applied by the gas inside the battery cell 20 to push the extruding member 23422 to move.

[0141] Please refer to Fig.14 In some embodiments, the main body 2341 also includes a connecting portion 23417, which is connected to the limiting portion 23415 and extends in a direction away from the accommodating cavity 235. The connecting portion 23417 is configured to be connected to the end cover 233 to install the pressure relief mechanism 234 on the end cover 233.

[0142] like Fig.14As shown, in some embodiments, the surface of the connecting portion 23417 facing the interior of the battery cell 20 is connected to the surface of the limiting structure 23416 facing the interior of the battery cell 20 and is located on the same plane, and the pressure relief mechanism 234 is located outside the battery cell 20, will not occupy the internal space of the battery cell 20, and will not affect the energy density of the battery cell 20.

[0143] It should be noted that the interior of the battery cell of the present application refers to the housing 21 (see Figure 3 ) and a side of the end cover 233 facing the electrode assembly 22 define a housing portion for accommodating the electrode assembly 22, and the outside of the battery cell refers to the space outside the housing portion.

[0144] There are many ways to connect the connecting portion 23417 to the end cover 233. For example, in some embodiments, the connecting portion 23417 and the end cover 233 are welded, or the connecting portion 23417 and the end cover 233 are connected by screws or bolts.

[0145] In some embodiments, the end cap 233 has a recessed portion 2332 recessed toward the inside of the battery cell 20, and the recessed portion 2332 is configured to accommodate at least part of the pressure relief mechanism 234. At least part of the pressure relief mechanism 234 is accommodated in the recessed portion 2332, which can reduce the structural size of the battery cell 20 and reduce the space occupied by the battery cell 20.

[0146] In some embodiments, the connection portion 23417 of the body 2341 is located in the recess 2332 and connected to the end cover 233 . For example, the end of the connection portion 23417 away from the limiting portion 23415 can be used for welding to the side wall 23321 of the recess 2332 .

[0147] In some embodiments, the bottom wall 23322 of the recessed portion 2332 is provided with a support portion 23323, the pressure relief mechanism 234 is located on the side of the support portion 23323 away from the inside of the battery cell 20, and a slot for providing a sealing structure 237 is formed between the side of the connection portion 23417 facing the inside of the battery cell 20, the support portion 23323 and the bottom wall 23322 of the recessed portion 2332, so as to achieve a sealed connection between the pressure relief mechanism 234 and the end cover 233. When the end of the connection portion 23417 away from the limiting portion 23415 is welded to the side wall 23321 of the recessed portion 2332, the support portion 23323 can also play a certain role in heat insulation, reducing the damage of the sealing structure 237 and other structures to the heat generated by welding.

[0148] In some embodiments, along the radial direction of the accommodating cavity 235, one end of the connecting portion 23417 away from the limiting portion 23415 and the limiting portion 23415 are respectively located on both sides of the supporting member, and the distance between the one end of the connecting portion 23417 away from the limiting portion 23415 and the supporting portion 23323 is greater than or equal to a preset distance. When the one end of the connecting portion 23417 away from the limiting portion 23415 is welded to the side wall 23321 of the recessed portion 2332, high temperature damage to the supporting portion 23323 and the sealing structure 237 due to welding can be avoided.

[0149] Please refer to Fig.15 , Fig.15 The flowchart of the manufacturing method of the battery cell 20 provided in some embodiments of the present application. The manufacturing method of the battery cell 20 provided in the embodiment of the present application includes:

[0150] Step S100, providing a housing 21, wherein the housing 21 has an opening 211;

[0151] Step S200, providing a motor assembly

[0152] Step S300, providing an end cap assembly 23, the end cap assembly 23 comprising: an end cap 233 and a pressure relief mechanism 234, the pressure relief mechanism 234 being connected to the end cap 233, the pressure relief mechanism 234 being configured to: be in a first pressure relief state when the internal pressure or temperature of the battery cell 20 is greater than or equal to a first threshold value and less than a second threshold value, so as to release the internal pressure of the battery cell 20; be in a second pressure relief state when the internal pressure or temperature of the battery cell 20 is greater than or equal to a second threshold value, so as to release the internal pressure of the battery cell 20; wherein the pressure relief area of ​​the pressure relief mechanism 234 in the first pressure relief state is smaller than the pressure relief area of ​​the pressure relief mechanism 234 in the second pressure relief state;

[0153] In step S400 , the electrode assembly 22 is accommodated in the housing 21 and the opening 211 is closed by the end cover assembly 23 .

[0154] It should be noted that the execution order of step S100, step S200 and step S300 is not limited in the present embodiment. For example, step S200 may be executed first, then step S100, and then step S300. The relevant structure of the battery cell 20 manufactured by the manufacturing method of the battery cell 20 can refer to the battery cell 20 provided in the above embodiments.

[0155] Please refer to Fig.16 , Fig.16 The structure block diagram of the battery cell manufacturing device 2000 provided in some embodiments of the present application. The battery cell manufacturing device 2000 provided in the embodiment of the present application includes a providing device 2100 and an installing device 2200.

[0156] The providing device 2100 is configured to provide a housing 21 , provide an electrode assembly 22 , and provide an end cap 233 .

[0157] The housing 21 has an opening 211 .

[0158] The end cover assembly 23 includes: an end cover 233 and a pressure relief mechanism 234, the pressure relief mechanism 234 is connected to the end cover 233, and the pressure relief mechanism 234 is configured to: be in a first pressure relief state when the internal pressure or temperature of the battery cell 20 is greater than or equal to a first threshold value and less than a second threshold value, so as to release the internal pressure of the battery cell 20; be in a second pressure relief state when the internal pressure or temperature of the battery cell 20 is greater than or equal to a second threshold value, so as to release the internal pressure of the battery cell 20; wherein the pressure relief area of ​​the pressure relief mechanism 234 in the first pressure relief state is smaller than the pressure relief area of ​​the pressure relief mechanism 234 in the second pressure relief state.

[0159] The mounting device 2200 is configured to accommodate the electrode assembly 22 in the housing 21 and close the opening 211 through the end cap assembly 23 .

[0160] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An end cap assembly for a battery cell, characterized in that: include: End caps; as well as A pressure relief mechanism connected to the end cover, the pressure relief mechanism comprising a body, the body having a butting portion and a limiting portion, the limiting portion being arranged around the outer periphery of the butting portion, the limiting portion and the butting portion jointly defining a receiving cavity, the limiting portion being provided with a pressure relief port including a first pressure relief port and a second pressure relief port which are independent of each other, the first pressure relief port being closer to the interior of the battery cell than the second pressure relief port, the pressure relief mechanism being configured to be in a first pressure relief state of pressure relief from the pressure relief port when the internal pressure or temperature of the battery cell is greater than or equal to a first threshold value and less than a second threshold value, so as to release the internal pressure of the battery cell; When the pressure or temperature inside the battery cell is greater than or equal to the second threshold, the battery cell is in a second pressure relief state of releasing pressure from the pressure relief port to release the pressure inside the battery cell; Wherein, a pressure relief area of ​​the pressure relief mechanism in the first pressure relief state is smaller than a pressure relief area of ​​the pressure relief mechanism in the second pressure relief state.

2. The end cap assembly according to claim 1, characterized in that: The pressure relief mechanism also includes an opening device; The opening device is configured to open at least a portion of the pressure relief port when the pressure relief mechanism is in the first pressure relief state and the second pressure relief state, so as to release the pressure inside the battery cell through the pressure relief port; Wherein, in the first pressure relief state, the pressure relief area of ​​the pressure relief port is smaller than the pressure relief area of ​​the pressure relief port in the second pressure relief state.

3. The end cap assembly according to claim 2, characterized in that: When the pressure relief mechanism is in the first pressure relief state, the first pressure relief port is opened and the second pressure relief port is closed; when the pressure relief mechanism is in the second pressure relief state, both the first pressure relief port and the second pressure relief port are opened.

4. The end cap assembly according to claim 2 or 3, characterized in that: The opening device includes a blocking member, and the blocking member is connected to the body; The blocking member is configured to be subjected to force to open at least a portion of the pressure relief port when the pressure or temperature inside the battery cell is greater than or equal to the first threshold.

5. The end cap assembly according to claim 4, characterized in that: The opening device further comprises an extrusion member, which is movably disposed on the body; The extruding member is configured to move relative to the body when the pressure or temperature inside the battery cell is greater than or equal to the first threshold value, so that the blocking member is compressed by force to open at least a portion of the pressure relief port.

6. The end cap assembly according to claim 5, characterized in that: The extrusion member is closer to the interior of the battery cell than the abutment portion; The abutting portion is configured to cooperate with the extrusion member to squeeze the blocking member when the pressure or temperature inside the battery cell is greater than or equal to the first threshold, so that the blocking member is compressed to open at least a portion of the pressure relief port.

7. The end cap assembly according to claim 6, characterized in that: The accommodating cavity is used to accommodate the extruding member and the blocking member.

8. The end cap assembly according to claim 7, characterized in that: There is a gap between the inner wall of the limiting portion and the outer wall of the extrusion piece.

9. The end cap assembly according to any one of claims 5 to 8, characterized in that: The body further includes a limiting structure configured to support the extrusion member to move toward an inner direction of the battery cell.

10. The end cap assembly according to claim 9, characterized in that: The limiting structure is a ring structure.

11. The end cap assembly according to any one of claims 1 to 10, characterized in that: The end cover has a recessed portion recessed toward the interior of the battery cell, and the recessed portion is configured to accommodate at least a portion of the pressure relief mechanism.

12. A battery cell, characterized in that: include: a housing having an opening; an electrode assembly, contained in the housing; as well as According to the end cover assembly according to any one of claims 1 to 11, the end cover is used to seal the opening.

13. A battery, characterized in that: include: Box; as well as The battery cell according to claim 12, wherein the battery cell is accommodated in the box body.

14. An electrical device, characterized in that: Comprising the battery cell according to claim 12.

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