Battery cell, method and system for manufacturing the same, battery, and electric device

Abstract

This application provides a battery cell, its manufacturing method and system, a battery, and an electrical device. The battery cell includes a casing and an electrode assembly housed within the casing. The casing includes a wall portion, which in turn includes a main body portion, a connecting portion, and a reinforcing portion. The connecting portion surrounds the outside of the reinforcing portion, and the main body portion surrounds the outside of the connecting portion. The connecting portion has a weak area, and the battery cell is configured to rupture along the weak area when the internal pressure of the battery cell reaches a threshold, thereby releasing the internal pressure. The maximum thickness of the reinforcing portion is greater than the maximum thickness of the main body portion to reduce the deformation of the reinforcing portion under internal pressure. This application can reduce the risk of rupture of the weak area during normal use, extend the service life of the battery cell, and improve the safety of the battery cell.

Description

Technical Field

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

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

[0003] In the development of battery technology, besides improving the performance of individual battery cells, safety is also a crucial issue. If the safety of a battery cell cannot be guaranteed, then that cell cannot be used. Therefore, how to enhance the safety of individual battery cells is a pressing technical problem that needs to be solved in battery technology. Summary of the Invention

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

[0005] In a first aspect, embodiments of this application provide a battery cell, including a housing and an electrode assembly housed within the housing. The housing includes a wall portion, which further includes a main body portion, a connecting portion, and a reinforcing portion. The connecting portion surrounds the outside of the reinforcing portion, and the main body portion surrounds the outside of the connecting portion. The connecting portion has a weak area, and the battery cell is configured to rupture along the weak area when the internal pressure of the battery cell reaches a threshold, thereby releasing the internal pressure. The maximum thickness of the reinforcing portion is greater than the maximum thickness of the main body portion to reduce the deformation of the reinforcing portion under the action of internal pressure.

[0006] When a battery cell experiences thermal runaway, the wall deforms under internal pressure. In the above design, the main body has a smaller thickness than the reinforcing part, making it more prone to deformation under internal pressure. When the main body deforms, stress is transferred to the connecting part. However, because the reinforcing part is thicker and less deformable, it cannot release the stress on the connecting part through deformation. Thus, the weak area must simultaneously bear the stress and internal pressure, making it more susceptible to rupture. Therefore, compared to traditional pressure relief mechanisms, the above design increases the thickness of the weak area without changing the internal pressure required for rupture, thereby reducing the risk of rupture during normal use, extending the battery cell's lifespan, and improving its safety.

[0007] In some embodiments, the wall portion includes a first recess that is recessed from a side of the wall portion away from the electrode assembly in a direction facing the electrode assembly. The reinforcement includes a first protrusion that protrudes from the bottom surface of the first recess, at least partially received within the first recess. A connecting portion is formed in a region corresponding to the bottom surface of the first recess.

[0008] The above solution reduces the thickness of the connection by creating a first recess in the wall, thereby reducing the strength of the weak area so that the weak area can rupture when the internal pressure of the battery cell reaches a threshold.

[0009] In some embodiments, the first protrusion is entirely housed within the first recess. The first recess can completely accommodate the first protrusion, thus preventing the first protrusion from increasing the maximum dimension of the casing in the thickness direction and improving the energy density of the battery cell.

[0010] In some embodiments, the reinforcing portion protrudes from the surface of the main body facing the electrode assembly. This arrangement causes the reinforcing portion to protrude towards the electrode assembly, thereby increasing the thickness and strength of the reinforcing portion.

[0011] In some embodiments, the wall portion further includes a second recess, which is recessed from the side of the wall portion facing the electrode assembly in a direction away from the electrode assembly. A connecting portion is formed between the bottom surface of the first recess and the bottom surface of the second recess. The reinforcing portion further includes a second protrusion protruding from the bottom surface of the second recess, at least partially received within the second recess.

[0012] When the thickness of the connecting part is constant, if the first recess is only provided on one side of the connecting part, the depth of the first recess will be relatively large, making its molding more difficult. The above solution forms the connecting part by creating both a first recess and a second recess, thus reducing the depth requirements of both recesses and lowering the molding difficulty. Furthermore, the above solution can further increase the thickness of the reinforcing part by providing a second protrusion.

[0013] In some embodiments, the main body includes a body portion with an inner surface and an outer surface disposed opposite each other. The inner surface faces the electrode assembly, and a first recess extends from the outer surface in the direction facing the electrode assembly. A second protrusion protrudes from the inner surface. In the above embodiment, the second protrusion protrudes from the inner surface so that the maximum thickness of the reinforcing portion is greater than the maximum thickness of the body portion.

[0014] In some embodiments, the main body portion further includes a third protrusion protruding from the inner surface, a second recess recessing from the top surface of the third protrusion in a direction away from the electrode assembly, and the third protrusion surrounding the outside of the second recess.

[0015] In the above scheme, the third protrusion can not only strengthen the wall at the location where the second recess is formed, but also increase the depth of the second recess, providing more material for the strengthening part.

[0016] In some embodiments, the second protrusion is entirely housed within the second recess. The second recess can completely accommodate the second protrusion, thereby reducing the risk of interference between the second protrusion and other structures within the battery cell.

[0017] In some embodiments, the top surfaces of the second protrusion and the third protrusion are flush. This design allows for maximizing the thickness of the reinforcing portion without increasing the maximum dimension of the wall portion along the thickness direction.

[0018] In some embodiments, in the thickness direction of the wall portion, the bottom surface of the second recess is closer to the electrode assembly than the inner surface.

[0019] Given a fixed thickness of the connection portion, the closer the bottom surface of the second recess is to the electrode assembly, the closer the bottom surface of the first recess is to the electrode assembly. This design brings the bottom surface of the second recess closer to the electrode assembly than the inner surface, thereby increasing the distance between the bottom surface and the outer surface of the first recess. This reduces the risk of damage to the weak areas of the connection portion from external components, improving the safety and lifespan of the battery cell.

[0020] In some embodiments, the reinforcing portion includes a third recess that extends from the top surface of the second protrusion in a direction away from the electrode assembly. In the thickness direction of the wall portion, the distance between the bottom surface of the third recess and the top surface of the first protrusion is greater than the maximum thickness of the main body portion.

[0021] In the above design, the internal space of the battery cell can be increased by creating a third recess, allowing the casing to hold more electrolyte and improving the performance of the battery cell. The thickness of the portion of the reinforcing part located between the bottom surface of the third recess and the top surface of the first protrusion is greater than the maximum thickness of the main body to ensure that the strength of the reinforcing part meets the requirements.

[0022] In some embodiments, in the thickness direction of the wall portion, the depth of the third recess is less than the dimension by which the second protrusion protrudes from the bottom surface of the second recess.

[0023] The above solution controls the depth of the third recess so that the thickness of the portion of the reinforcing part located between the bottom surface of the third recess and the top surface of the first protrusion is greater than the maximum thickness of the main body, thus ensuring that the strength of the reinforcing part meets the requirements.

[0024] In some embodiments, the connecting portion is provided with a groove to form a weak area in the area corresponding to the groove.

[0025] The above solution creates a weak area in the connection by opening a groove in the connection part, so that the strength of the weak area is less than the strength of other areas of the connection part.

[0026] In some embodiments, the wall portion further includes: a bend portion surrounding the outside of the body portion and extending in a direction facing the electrode assembly to form a fourth recess on the side of the body portion facing the electrode assembly; and a plate portion surrounding the outside of the bend portion, the fourth recess being recessed relative to the surface of the plate portion facing the electrode assembly.

[0027] The above solution, by incorporating a fourth recess, can increase the internal space of the battery cell and improve its capacity. Simultaneously, the fourth recess also provides space for the reinforcing section, ensuring it has sufficient thickness.

[0028] In some embodiments, the housing includes a shell and an end cap, the shell having an opening and the end cap for closing the opening of the shell. The end cap is a wall portion.

[0029] In some embodiments, the end cap is an integrally formed structure. The above solution integrates the connecting part and the reinforcing part with pressure relief function into the end cap to simplify the structure of the battery cell.

[0030] Secondly, embodiments of this application provide a battery comprising a plurality of battery cells according to any of the embodiments of the first aspect.

[0031] Thirdly, embodiments of this application provide an electrical device including a battery cell according to any of the embodiments of the first aspect, wherein the battery cell is used to provide electrical energy.

[0032] Fourthly, embodiments of this application provide a method for manufacturing a single battery cell, comprising:

[0033] Provide electrode assemblies;

[0034] A housing is provided, the housing including a wall portion, the wall portion including a main body portion, a connecting portion and a reinforcing portion, the connecting portion surrounding the outside of the reinforcing portion, and the main body portion surrounding the outside of the connecting portion;

[0035] Install the electrode assembly into the housing;

[0036] The connecting part has a weak area, and the battery cell is configured to rupture along the weak area when the internal pressure of the battery cell reaches a threshold, so as to release the internal pressure; the maximum thickness of the reinforcing part is greater than the maximum thickness of the main body part, so as to reduce the deformation of the reinforcing part under the action of internal pressure.

[0037] Fifthly, embodiments of this application provide a manufacturing system for a single battery cell, comprising:

[0038] A first supplying device is used to supply electrode assemblies;

[0039] The second providing device is used to provide a housing, the housing including a wall portion, the wall portion including a main body portion, a connecting portion and a reinforcing portion, the connecting portion surrounding the outside of the reinforcing portion, and the main body portion surrounding the outside of the connecting portion;

[0040] Assembly device for mounting electrode assemblies into a housing;

[0041] The connecting part has a weak area, and the battery cell is configured to rupture along the weak area when the internal pressure of the battery cell reaches a threshold, so as to release the internal pressure; the maximum thickness of the reinforcing part is greater than the maximum thickness of the main body part, so as to reduce the deformation of the reinforcing part under the action of internal pressure. Attached Figure Description

[0042] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0043] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0044] Figure 2 Explosion diagrams of batteries provided for some embodiments of this application;

[0045] Figure 3 for Figure 2 An exploded view of the battery module shown.

[0046] Figure 4 This is an exploded schematic diagram of a battery cell provided in some embodiments of this application;

[0047] Figure 5 for Figure 4 The diagram shows the structure of the end cap;

[0048] Figure 6 for Figure 5 A cross-sectional schematic diagram of the end cap shown;

[0049] Figure 7 for Figure 6 An enlarged schematic diagram of the end cap at point A in the circle shown;

[0050] Figure 8 A partial cross-sectional view of the end cap of a battery cell provided in some other embodiments of this application;

[0051] Figure 9 A schematic flowchart illustrating a method for manufacturing a single battery cell according to some embodiments of this application;

[0052] Figure 10 This is a schematic block diagram of a battery cell manufacturing system provided for some embodiments of this application.

[0053] The accompanying drawings are not drawn to scale. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0055] 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.

[0056] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0057] 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.

[0058] 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.

[0059] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0060] In this application, "multiple" means two or more (including two).

[0061] In this application, the battery cell may include a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, etc., and the embodiments of this application are not limited thereto. The battery cell may be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this application are not limited thereto.

[0062] The battery mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application may include a battery module or a battery pack. A battery generally includes a housing for encapsulating one or more battery cells. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0063] A single battery cell includes electrode components and an electrolyte. The electrode components include a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of metal ions between the positive and negative electrodes. The positive electrode includes a positive current collector and a positive active material layer, which is coated on the surface of the positive current collector. The positive current collector includes a positive electrode coating area and a positive electrode tab connected to the coating area. The coating area is coated with the positive active material layer, while the tab is not. Taking a lithium-ion battery cell as an example, the positive current collector can be made of aluminum, and the positive active material layer includes the positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode sheet includes a negative current collector and a negative active material layer, the negative active material layer being coated on the surface of the negative current collector. The negative current collector includes a negative electrode coating area and a negative electrode tab connected to the negative electrode coating area. The negative electrode coating area is coated with the negative active material layer, while the negative electrode tab is not coated with the negative active material layer. The material of the negative current collector can be copper, and the negative active material layer includes negative active material, which can be carbon or silicon, etc. The material of the separator can be PP (polypropylene) or PE (polyethylene), etc.

[0064] The battery cell also includes a casing, inside which a cavity is formed to house the electrode assembly. The casing protects the electrode assembly from external contaminants to prevent them from being affected by external objects during charging or discharging.

[0065] The development of battery technology must take into account multiple design factors, such as energy density, cycle life, discharge capacity, charge / discharge rate and other performance parameters. In addition, battery safety also needs to be considered.

[0066] The pressure relief mechanism on a battery cell has a significant impact on its safety. For example, in the event of a short circuit or overcharging, thermal runaway may occur inside the battery cell, causing a sudden increase in pressure. In such cases, the pressure relief mechanism can be activated to release the internal pressure, preventing the battery cell from exploding or catching fire.

[0067] A pressure relief mechanism is a component or part that is activated to release internal pressure when the internal pressure of a battery cell reaches a predetermined threshold. This threshold design varies depending on design requirements. It may depend on the materials of one or more of the components in the battery cell: the positive electrode, the negative electrode, the electrolyte, and the separator.

[0068] The pressure relief mechanism can take the form of an explosion-proof valve, a gas valve, a pressure relief valve, or a safety valve, and can specifically adopt a pressure-sensitive element or structure. That is, when the internal pressure of a battery cell reaches a predetermined threshold, the pressure relief mechanism performs an action or a weak area provided in the pressure relief mechanism ruptures, thereby forming an opening or channel for internal pressure to be released.

[0069] The term "actuation" as used in this application refers to the activation or actuation of the pressure relief mechanism to a certain state, thereby releasing the internal pressure of the battery cell. The actions of the pressure relief mechanism may include, but are not limited to, at least a portion of the mechanism rupturing, breaking, tearing, or opening. When the pressure relief mechanism is actuated, the high-temperature, high-pressure substances inside the battery cell are discharged as waste from the actuated portion. This method allows for pressure relief of the battery cell under controlled pressure, thereby preventing potentially more serious accidents.

[0070] The emissions from battery cells mentioned in this application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0071] To simplify the structure of individual battery cells, the inventors attempted to integrate pressure relief mechanisms into the casing. For example, they created weak zones on the casing, which are designed to rupture and release internal pressure when the internal pressure of the battery cell reaches a threshold. In the event of a short circuit or overcharging, thermal runaway may occur inside the battery cell, causing a sudden pressure surge. In such cases, the rupture of the weak zone creates a channel to release internal pressure, reducing the risk of battery cell explosion and fire, thereby improving safety.

[0072] The thickness of the weak zone is directly related to the internal pressure required to actuate it (hereinafter referred to as actuation pressure). The inventors discovered that in order for the weak zone to rupture under actuation pressure, it typically has a small thickness. Later in the battery cell's cycle life, the weak zone is prone to rupture due to long-term electrolyte corrosion, leading to electrolyte leakage and safety risks. The weak zone also has low strength, making it susceptible to rupture under external impact, causing battery cell failure. Furthermore, the smaller the thickness of the weak zone, the worse its thickness uniformity during molding, which affects the consistency of actuation pressure across different parts of the weak zone.

[0073] In view of this, this application provides a technical solution in which a battery cell includes a casing and an electrode assembly housed within the casing. The casing includes a wall portion, which in turn includes a main body portion, a connecting portion, and a reinforcing portion. The connecting portion surrounds the outside of the reinforcing portion, and the main body portion surrounds the outside of the connecting portion. The connecting portion has a weak area, and the battery cell is configured to rupture along the weak area when the internal pressure of the battery cell reaches a threshold, thereby releasing the internal pressure. The maximum thickness of the reinforcing portion is greater than the maximum thickness of the main body portion to reduce the deformation of the reinforcing portion under the action of internal pressure. This technical solution can increase the thickness of the weak area without changing the internal pressure required for the weak area to rupture, thereby reducing the risk of the weak area rupturing during normal use, extending the service life of the battery cell, and improving the safety of the battery cell.

[0074] The technical solutions described in the embodiments of this application are applicable to batteries and electrical devices that use batteries.

[0075] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0076] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0077] Figure 1 The diagram shows the structural features of a vehicle provided in some embodiments of this application.

[0078] like Figure 1 As shown, a battery 2 is installed inside the vehicle 1. The battery 2 can be located at the bottom, front, or rear of the vehicle 1. The battery 2 can be used to power the vehicle 1; for example, the battery 2 can serve as the operating power source for the vehicle 1.

[0079] Vehicle 1 may also include controller 3 and motor 4. Controller 3 is used to control battery 2 to supply power to motor 4, for example, for the power needs of vehicle 1 during start-up, navigation and driving.

[0080] In some embodiments of this application, the battery 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0081] Figure 2 This is an exploded schematic diagram of a battery provided for some embodiments of this application.

[0082] like Figure 2 As shown, battery 2 includes a housing 5 and battery cells (not shown), with the battery cells housed within the housing 5.

[0083] The housing 5 is used to house individual battery cells, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the individual battery cells. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as cylinders, cuboids, etc.

[0084] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0085] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0086] In battery 2, there can be one or more individual battery cells. If there are multiple individual battery cells, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple individual battery cells are connected in both series and parallel configurations. Multiple individual battery cells can be directly connected in series, parallel, or in a mixed configuration and then housed within housing 5. Alternatively, multiple individual battery cells can first be connected in series, parallel, or in a mixed configuration to form battery module 6, and then multiple battery modules 6 can be connected in series, parallel, or in a mixed configuration to form a whole and housed within housing 5.

[0087] Figure 3 for Figure 2 The diagram shows an exploded view of the battery module.

[0088] In some embodiments, such as Figure 3 As shown, there are multiple battery cells 7, which are first connected in series, parallel, or a combination of both to form a battery module 6. These battery modules 6 are then connected in series, parallel, or a combination of both to form a whole, which is housed within the casing.

[0089] Multiple battery cells 7 in battery module 6 can be electrically connected through a busbar component to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6.

[0090] Figure 4 This is an exploded schematic diagram of a battery cell provided in some embodiments of this application.

[0091] like Figure 4 As shown, the battery cell 7 includes a housing 20 and an electrode assembly 10 housed within the housing 20.

[0092] The electrode assembly 10 is the core component for enabling the charging and discharging function of the battery cell 7. It includes a positive electrode, a negative electrode, and a separator. The positive and negative electrodes have opposite polarities, and the separator is used to insulate and isolate the positive and negative electrodes. The electrode assembly 10 mainly relies on the movement of metal ions between the positive and negative electrodes to operate.

[0093] There can be one or more electrode assemblies 10. When there are multiple electrode assemblies 10, they can be stacked. For example, as shown... Figure 4 As shown, there are four electrode assemblies 10.

[0094] The outer shell 20 is a hollow structure, with an internal cavity for accommodating the electrode assembly 10 and the electrolyte. The outer shell 20 can be of various shapes, such as a cylinder or a cuboid. The shape of the outer shell 20 can be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 is a cylindrical structure, a cylindrical outer shell can be used; if the electrode assembly 10 is a cuboid structure, a cuboid outer shell can be used.

[0095] In some embodiments, the housing 20 includes a housing 21 and an end cap 22, the housing 21 having an opening and the end cap 22 closing the opening.

[0096] The housing 21 may have an opening on one side, and the end cap 22 may be one that covers the opening of the housing 21. Alternatively, the housing 21 may have an opening on both sides, and the end caps 22 may be two, with the two end caps 22 respectively covering the two openings of the housing 21.

[0097] For example, the end cap 22 is attached to the housing 21 by welding, bonding, snap-fitting or other means.

[0098] In some embodiments, the housing 21 has an opening on one side and includes a bottom wall and at least one side wall connected to the bottom wall, with the side wall surrounding the bottom wall.

[0099] In some examples, the housing 21 is a cylindrical housing. Specifically, the housing 21 includes a cylindrical sidewall, one end of which is connected to the bottom wall, and the other end of which forms an opening opposite to the bottom wall.

[0100] In other examples, the shell 21 is a cuboid shell. Specifically, the shell 21 includes four flat sidewalls that form an opening opposite the bottom wall.

[0101] In some embodiments, the battery cell 7 further includes two electrode terminals 30, which may be disposed on the end cap 22. The two electrode terminals 30 are a positive electrode terminal and a negative electrode terminal, respectively. The positive electrode terminal is used to electrically connect with the positive electrode plate of the electrode assembly 10, and the negative electrode terminal is used to electrically connect with the negative electrode plate, so as to lead the electrical energy generated by the electrode assembly 10 out of the housing 20.

[0102] In some embodiments, each electrode terminal 30 is provided with a corresponding connecting member 40, or a current collector, which is located between the end cap 22 and the electrode assembly 10, for electrically connecting the electrode terminal 30 and the corresponding electrode sheet.

[0103] Figure 5 for Figure 4 The diagram shows the structure of the end cap; Figure 6 for Figure 5 A cross-sectional schematic diagram of the end cap shown; Figure 7 for Figure 6 The diagram shows an enlarged view of the end cap at point A in the circle.

[0104] Reference Figures 4 to 7 The battery cell 7 provided in this application embodiment includes a housing 20 and an electrode assembly 10 housed within the housing 20. The housing 20 includes a wall portion, which comprises a main body portion 23, a connecting portion 24, and a reinforcing portion 25. The connecting portion 24 surrounds the outside of the reinforcing portion 25, and the main body portion 23 surrounds the outside of the connecting portion 24. The connecting portion 24 is provided with a weak region 241. The battery cell 7 is configured to rupture along the weak region 241 when the internal pressure of the battery cell 7 reaches a threshold, thereby releasing the internal pressure. The maximum thickness of the reinforcing portion 25 is greater than the maximum thickness of the main body portion 23 to reduce the deformation of the reinforcing portion 25 under internal pressure.

[0105] In some examples of this application, the wall may be an end cap 22. In other examples, the wall may be part of the housing 21, for example, the wall may be either a side wall or a bottom wall of the housing 21.

[0106] For the sake of brevity, the accompanying drawings and the following description use end cap 22 as the wall portion. It should be understood that the wall portion described in this application is not limited to end cap 22.

[0107] The connecting part 24 has a ring-shaped structure and connects the main body part 23 and the reinforcing part 25. The inner end of the connecting part 24 is connected to the reinforcing part 25, and its outer end is connected to the main body part 23.

[0108] The strength of the weak region 241 is less than the strength of the main body 23, the strength of the reinforcing part 25, and the strength of other areas of the connecting part 24. For example, the thickness of the weak region 241 is less than the thickness of the main body 23, the thickness of the reinforcing part 25, and the thickness of other areas of the connecting part 24. In this embodiment, the thickness and strength of the weak region 241 can be reduced by creating grooves, scoring, or other structures on the connecting part 24, so that the weak region 241 can rupture when the internal pressure of the battery cell 7 reaches a threshold.

[0109] The thickness of the reinforcing part 25 refers to the dimension of the reinforcing part 25 in the thickness direction Z of the wall portion, and the thickness of the main body part 23 refers to the dimension of the main body part 23 in the thickness direction Z of the wall portion. In the description of the embodiments of this application, thickness refers to the dimension of the solid portion along the thickness direction Z.

[0110] The connecting part 24 and the reinforcing part 25 constitute the pressure relief mechanism of the battery cell 7. Exemplarily, after the weak area 241 ruptures, the reinforcing part 25 can be completely detached from the main body 23 under the action of internal pressure, or it can remain connected to the main body 23 and fold outward.

[0111] When thermal runaway occurs in the battery cell 7, the wall deforms under internal pressure. In this embodiment, the main body 23 has a smaller thickness than the reinforcing part 25, making it more prone to deformation under internal pressure. When the main body 23 deforms, stress is transferred to the connecting part 24. However, because the reinforcing part 25 is thicker and less deformable, it is difficult for the reinforcing part 25 to release the stress on the connecting part 24 through deformation. Thus, the weak area 241 must simultaneously bear the stress and internal pressure, making it more susceptible to rupture. Therefore, compared to traditional pressure relief mechanisms, this embodiment can increase the thickness of the weak area 241 without changing the internal pressure required for the weak area 241 to rupture, thereby reducing the risk of rupture during normal use, extending the service life of the battery cell 7, and improving the safety of the battery cell 7.

[0112] Compared to traditional pressure relief mechanisms, this embodiment can increase the thickness of the weak area 241, thereby simplifying the molding process of the weak area 241, improving the uniformity of its thickness during the molding process, and ensuring the consistency of the internal pressure required for different parts of the weak area 241 to rupture.

[0113] In some embodiments, the wall portion includes a first recess 26, which is recessed from the side of the wall portion away from the electrode assembly 10 in a direction facing the electrode assembly 10. The reinforcing portion 25 includes a first protrusion 251 protruding from the bottom surface of the first recess 26, at least a portion of which is received within the first recess 26. A connecting portion 24 is formed in a region corresponding to the bottom surface of the first recess 26.

[0114] The first recess 26 has an opening at the end opposite to the electrode assembly 10.

[0115] In some examples, the first protrusion 251 may be entirely contained within the first recess 26. In other examples, the first protrusion 251 may protrude beyond the first recess 26, and the first protrusion 251 may only be partially contained within the first recess 26.

[0116] At least a portion of the bottom surface of the first recess 26 is the surface of the connecting portion 24 that is away from the electrode assembly 10.

[0117] In this embodiment, the thickness of the connecting portion 24 is reduced by opening a first recess 26 on the wall, thereby reducing the strength of the weak area 241, so that the weak area 241 can rupture when the internal pressure of the battery cell 7 reaches a threshold.

[0118] In some embodiments, the first recess 26 can be formed by extruding the wall portion. During the extrusion molding process, a portion of the wall portion material flows to the reinforcing portion 25 to increase the thickness and strength of the reinforcing portion 25.

[0119] In some embodiments, the bottom surface of the first recess 26 is a plane perpendicular to the thickness direction Z.

[0120] In some embodiments, the first protrusion 251 is entirely received within the first recess 26.

[0121] In this embodiment, the first recess 26 can completely accommodate the first protrusion 251, which can prevent the first protrusion 251 from increasing the maximum size of the outer shell 20 in the thickness direction Z and improve the energy density of the battery cell 7.

[0122] In some embodiments, in the thickness direction Z, the depth of the first recess 26 is equal to the dimension by which the first protrusion 251 protrudes from the bottom surface of the first recess 26.

[0123] In some embodiments, the wall portion further includes a second recess 27, which is recessed from the side of the wall portion facing the electrode assembly 10 in a direction away from the electrode assembly 10. A connecting portion 24 is formed between the bottom surface of the first recess 26 and the bottom surface of the second recess 27. The reinforcing portion 25 further includes a second protrusion 252 protruding from the bottom surface of the second recess 27, at least a portion of which is received within the second recess 27.

[0124] The second recess 27 opens at the end facing the electrode assembly 10.

[0125] In some examples, the second protrusion 252 may be entirely contained within the second recess 27. In other examples, the second protrusion 252 may protrude beyond the second recess 27, and the second protrusion 252 may only be partially contained within the second recess 27.

[0126] When the thickness of the connecting portion 24 is constant, if the first recess 26 is only provided on one side of the connecting portion 24, the depth of the first recess 26 will be relatively large, making its molding more difficult. In this embodiment, the connecting portion 24 is formed by creating a first recess 26 and a second recess 27, which reduces the depth requirements of the first recess 26 and the second recess 27, thus lowering the molding difficulty. In this embodiment, the thickness of the reinforcing portion 25 can be further increased by providing a second protrusion 252.

[0127] In some embodiments, the second recess 27 is formed by extruding the wall portion. During the extrusion molding process, a portion of the wall portion material flows to the reinforcing portion 25 to increase the thickness and strength of the reinforcing portion 25.

[0128] In some embodiments, the main body 23 includes a body portion 231, which includes an inner surface 231a and an outer surface 231b disposed opposite to each other. The inner surface 231a faces the electrode assembly 10, and a first recess 26 is recessed from the outer surface 231b in the direction facing the electrode assembly 10. A second protrusion 252 protrudes from the inner surface 231a.

[0129] The inner surface 231a and the outer surface 231b are disposed opposite each other along the thickness direction Z, with the inner surface 231a facing the electrode assembly 10 and the outer surface 231b facing away from the electrode assembly 10. For example, both the inner surface 231a and the outer surface 231b are planes perpendicular to the thickness direction Z, and the distance between the inner surface 231a and the outer surface 231b is the thickness of the body portion 231.

[0130] In this embodiment, the second protrusion 252 protrudes from the inner surface 231a, so that the maximum thickness of the reinforcing part 25 is greater than the maximum thickness of the body part 231.

[0131] In some embodiments, the first protrusion 251 does not protrude from the outer surface 231b; exemplaryly, the outer surface 231b and the top surface of the first protrusion 251 are flush.

[0132] In some embodiments, the main body 23 further includes a third protrusion 232 protruding from the inner surface 231a, a second recess 27 recessed from the top surface of the third protrusion 232 in a direction away from the electrode assembly 10, and the third protrusion 232 surrounds the outside of the second recess 27.

[0133] In this embodiment, the third protrusion 232 can not only strengthen the wall at the location where the second recess 27 is formed, but also increase the depth of the second recess 27, providing more material for the reinforcing part 25.

[0134] In some embodiments, the second protrusion 252 is entirely accommodated within the second recess 27.

[0135] In this embodiment, the second recess 27 can completely accommodate the second protrusion 252, which can reduce the risk of interference between the second protrusion 252 and other structures inside the battery cell 7.

[0136] In some embodiments, the top surface of the second protrusion 252 and the top surface of the third protrusion 232 are flush.

[0137] For example, the top surface of the second protrusion 252 and the top surface of the third protrusion 232 are both planes perpendicular to the thickness direction Z.

[0138] This embodiment can maximize the thickness of the reinforcing part 25 without increasing the maximum dimension of the wall part along the thickness direction Z.

[0139] In some embodiments, in the thickness direction Z of the wall portion, the bottom surface of the second recess 27 is closer to the electrode assembly 10 than the inner surface 231a.

[0140] Given a fixed thickness of the connecting portion 24, the closer the bottom surface of the second recess 27 is to the electrode assembly 10, the closer the bottom surface of the first recess 26 is to the electrode assembly 10. In this embodiment, the bottom surface of the second recess 27 is closer to the electrode assembly 10 than the inner surface 231a, thereby increasing the distance between the bottom surface of the first recess 26 and the outer surface 231b, reducing the risk of damage to the weak area 241 of the connecting portion 24 by external components, and improving the safety and service life of the battery cell 7.

[0141] In some embodiments, the reinforcing portion 25 is provided with a third recess 253, which extends from the top surface of the second protrusion 252 in a direction away from the electrode assembly 10. In the thickness direction Z of the wall portion, the distance between the bottom surface of the third recess 253 and the top surface of the first protrusion 251 is greater than the maximum thickness of the main body portion 23.

[0142] For example, the bottom surface of the third recess 253 and the top surface of the first protrusion 251 are arranged parallel to each other.

[0143] In this embodiment, by creating the third recess 253, the internal space of the battery cell 7 can be increased, allowing the casing 20 to hold more electrolyte and improving the performance of the battery cell 7. The thickness of the portion of the reinforcing part 25 located between the bottom surface of the third recess 253 and the top surface of the first protrusion 251 is greater than the maximum thickness of the main body 23, to ensure that the strength of the reinforcing part 25 meets the requirements.

[0144] In some embodiments, the third recess 253 may be formed by extrusion reinforcement 25. During the extrusion molding process, a portion of the material of reinforcement 25 moves and gathers towards the portion surrounding the third recess 253 to increase the maximum local thickness and strength of reinforcement 25.

[0145] In some embodiments, in the thickness direction Z of the wall portion, the depth of the third recess 253 is less than the dimension by which the second protrusion 252 protrudes from the bottom surface of the second recess 27.

[0146] In this embodiment, by controlling the depth of the third recess 253, the thickness of the portion of the reinforcing part 25 located between the bottom surface of the third recess 253 and the top surface of the first protrusion 251 is greater than the maximum thickness of the main body 23, thereby ensuring that the strength of the reinforcing part 25 meets the requirements.

[0147] In some embodiments, the connecting portion 24 is provided with a groove 242 to form a weak area 241 in the area corresponding to the groove 242.

[0148] The groove 242 can be provided on the surface of the connecting portion 24 facing the electrode assembly 10, or on the surface of the connecting portion 24 away from the electrode assembly 10. Along the thickness direction Z of the wall portion, the weak area 241 and the groove 242 are provided correspondingly.

[0149] For example, the groove 242 can be formed by machining material away from the connecting portion 24, which helps to reduce processing costs and processing difficulty. Alternatively, the groove 242 can also be formed by extruding the connecting portion 24.

[0150] In this embodiment, a groove 242 is formed on the connecting part 24 to create a weak area 241 on the connecting part 24, so that the strength of the weak area 241 is less than the strength of other areas of the connecting part 24.

[0151] In some embodiments, the wall portion further includes a bend 28 and a plate portion 29. The bend 28 surrounds the outside of the main body portion 23 and extends in the direction facing the electrode assembly 10 to form a fourth recess 29a on the side of the main body portion 23 facing the electrode assembly 10. The plate portion 29 surrounds the outside of the bend 28, and the fourth recess 29a is recessed relative to the surface of the plate portion 29 facing the electrode assembly 10.

[0152] For example, the wall portion is an end cap 22, and the plate portion 29 is used to connect to the housing 21.

[0153] In this embodiment, by providing the fourth recess 29a, the internal space of the battery cell 7 can be increased, thereby improving the capacity of the battery cell 7. At the same time, the fourth recess 29a can also provide space for the reinforcing part 25, enabling the reinforcing part 25 to have sufficient thickness.

[0154] In some embodiments, the maximum thickness of the reinforcing portion 25 is greater than the maximum thickness of the plate portion 29 and the maximum thickness of the bending portion 28.

[0155] In some embodiments, the housing 20 includes a housing 21 and an end cap 22, the housing 21 having an opening, and the end cap 22 for closing the opening of the housing 21. The end cap 22 is a wall portion.

[0156] Compared to the housing 21, it is easier to form structures such as the reinforcing part 25 and the connecting part 24 on the end cap 22.

[0157] In some embodiments, the end cap 22 is an integrally formed structure.

[0158] In this embodiment, the connecting part 24 with pressure relief function and the reinforcing part 25 are integrated on the end cover 22 to simplify the structure of the battery cell 7.

[0159] Figure 8 A partial cross-sectional view of the end cap of a battery cell provided in some other embodiments of this application.

[0160] like Figure 8 As shown, in some embodiments, the reinforcing portion 25 protrudes from the surface of the main body portion 23 facing the electrode assembly 10. In this embodiment, the reinforcing portion 25 protrudes from the electrode assembly 10 to increase the thickness and strength of the reinforcing portion 25.

[0161] In some embodiments, the surface of the main body 23 facing the electrode assembly 10 and the surface of the connecting portion 24 facing the electrode assembly 10 are flush.

[0162] Figure 9 This is a schematic flowchart illustrating a method for manufacturing a battery cell according to some embodiments of this application.

[0163] like Figure 9 As shown, the method for manufacturing a single battery cell according to an embodiment of this application includes:

[0164] S100, Provides electrode assemblies;

[0165] S200, providing an outer casing, the outer casing including a wall portion, the wall portion including a main body portion, a connecting portion and a reinforcing portion, the connecting portion surrounding the outside of the reinforcing portion, and the main body portion surrounding the outside of the connecting portion;

[0166] S300, Install the electrode assembly into the housing;

[0167] The connecting part has a weak area, and the battery cell is configured to rupture along the weak area when the internal pressure of the battery cell reaches a threshold, so as to release the internal pressure; the maximum thickness of the reinforcing part is greater than the maximum thickness of the main body part, so as to reduce the deformation of the reinforcing part under the action of internal pressure.

[0168] It should be noted that the relevant structure of the battery cell manufactured by the above-described battery cell manufacturing method can be found in the battery cells provided in the above embodiments.

[0169] When manufacturing a battery cell based on the above-described method, the steps do not necessarily need to be performed sequentially. That is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously. For example, steps S100 and S200 can be performed concurrently without any order.

[0170] Figure 10 This is a schematic block diagram of a battery cell manufacturing system provided for some embodiments of this application.

[0171] like Figure 10 As shown, the battery cell manufacturing system 90 of this application embodiment includes a first providing device 91, a second providing device 92, and an assembly device 93. The first providing device 91 provides electrode assemblies; the second providing device 92 provides a housing, the housing including a wall portion, a main body portion, a connecting portion, and a reinforcing portion, the connecting portion surrounding the outside of the reinforcing portion, and the main body portion surrounding the outside of the connecting portion; the assembly device 93 is used to install the electrode assemblies into the housing. The connecting portion has a weak area, and the battery cell is configured to rupture along the weak area when the internal pressure of the battery cell reaches a threshold, to release the internal pressure; the maximum thickness of the reinforcing portion is greater than the maximum thickness of the main body portion to reduce the deformation of the reinforcing portion under internal pressure.

[0172] The relevant structure of the battery cell manufactured by the above manufacturing system can be found in the battery cells provided in the above embodiments.

[0173] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0174] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A battery cell, comprising a housing and an electrode assembly housed within the housing; The outer casing includes a wall portion, which further includes a main body portion, a connecting portion, and a reinforcing portion. The connecting portion surrounds the outside of the reinforcing portion, and the main body portion surrounds the outside of the connecting portion. The housing includes a shell and an end cap. The shell has an opening, and the end cap is used to close the opening of the shell. The side wall of the shell, the bottom wall of the shell, or the end cap is configured as the wall portion. The connection portion is provided with a weak area, and the battery cell is configured to rupture along the weak area when the internal pressure of the battery cell reaches a threshold, so as to release the internal pressure; The maximum thickness of the reinforcing part is greater than the maximum thickness of the main body part, so as to reduce the deformation of the reinforcing part under the action of the internal pressure.

2. The battery cell according to claim 1, wherein, The wall portion includes a first recess, which is recessed from the side of the wall portion away from the electrode assembly in a direction facing the electrode assembly; The reinforcing portion includes a first protrusion protruding from the bottom surface of the first recess, and at least a portion of the first protrusion is accommodated within the first recess. The connecting portion is formed in the area corresponding to the bottom surface of the first recess.

3. The battery cell according to claim 2, wherein, The first protrusion is entirely accommodated within the first recess.

4. The battery cell according to claim 2 or 3, wherein, The reinforcing portion protrudes from the surface of the main body facing the electrode assembly.

5. The battery cell according to claim 2 or 3, wherein, The wall portion further includes a second recess, which is recessed from the side of the wall portion facing the electrode assembly in a direction away from the electrode assembly; The connecting portion is formed between the bottom surface of the first recess and the bottom surface of the second recess; The reinforcing portion further includes a second protrusion protruding from the bottom surface of the second recess, at least a portion of which is accommodated within the second recess.

6. The battery cell according to claim 5, wherein, The main body includes a body portion, which includes an inner surface and an outer surface disposed opposite to each other. The inner surface faces the electrode assembly, and the first recess is recessed from the outer surface in the direction facing the electrode assembly. The second protrusion protrudes from the inner surface.

7. The battery cell according to claim 6, wherein, The main body portion further includes a third protrusion protruding from the inner surface, the second recess being recessed from the top surface of the third protrusion in a direction away from the electrode assembly, and the third protrusion surrounding the outside of the second recess.

8. The battery cell according to claim 7, wherein, The second protrusion is entirely accommodated within the second recess.

9. The battery cell according to claim 8, wherein, The top surface of the second protrusion is flush with the top surface of the third protrusion.

10. The battery cell according to claim 7, wherein, In the thickness direction of the wall portion, the bottom surface of the second recess is closer to the electrode assembly than the inner surface.

11. The battery cell according to claim 5, wherein, The reinforcing portion is provided with a third recess, which extends from the top surface of the second protrusion in a direction away from the electrode assembly; In the thickness direction of the wall portion, the distance between the bottom surface of the third recess and the top surface of the first protrusion is greater than the maximum thickness of the main body portion.

12. The battery cell according to claim 11, wherein, In the thickness direction of the wall portion, the depth of the third recess is less than the dimension by which the second protrusion protrudes from the bottom surface of the second recess.

13. The battery cell according to any one of claims 1-3, wherein, The connecting portion is provided with a groove to form the weak area in the area corresponding to the groove.

14. The battery cell according to any one of claims 1-3, wherein, The wall portion also includes: A bent portion, surrounding the outside of the main body and extending in the direction facing the electrode assembly, forms a fourth recess on the side of the main body facing the electrode assembly; and The plate portion, surrounding the outside of the bent portion, has the fourth recess recessed relative to the surface of the plate portion facing the electrode assembly.

15. The battery cell according to any one of claims 1-3, wherein, The end cap is the wall portion.

16. The battery cell according to claim 15, wherein, The end cap is a one-piece structure.

17. A battery comprising a plurality of battery cells according to any one of claims 1-16.

18. An electrical device comprising a battery cell according to any one of claims 1-16, the battery cell being used to provide electrical energy.

19. A method for manufacturing a single battery cell, comprising: Provide electrode assemblies; A housing is provided, the housing including a wall portion, the wall portion including a main body portion, a connecting portion and a reinforcing portion, the connecting portion surrounding the outside of the reinforcing portion, and the main body portion surrounding the outside of the connecting portion; The electrode assembly is installed into the housing; The outer casing includes a housing and an end cap. The housing has an opening, and the end cap is used to cover the opening of the housing. The side wall of the housing, the bottom wall of the housing, or the end cap is configured as the wall portion. The connecting portion is provided with a weak area. The battery cell is configured to rupture along the weak area when the internal pressure of the battery cell reaches a threshold, so as to release the internal pressure. The maximum thickness of the reinforcing portion is greater than the maximum thickness of the main body portion, so as to reduce the deformation of the reinforcing portion under the action of the internal pressure.

20. A system for manufacturing a single battery cell, comprising: A first supplying device is used to supply electrode assemblies; A second providing device is used to provide a housing, the housing including a wall portion, the wall portion including a main body portion, a connecting portion and a reinforcing portion, the connecting portion surrounding the outside of the reinforcing portion, and the main body portion surrounding the outside of the connecting portion; An assembly device for mounting the electrode assembly into the housing; The outer casing includes a housing and an end cap. The housing has an opening, and the end cap is used to cover the opening of the housing. The side wall of the housing, the bottom wall of the housing, or the end cap is configured as the wall portion. The connecting portion is provided with a weak area. The battery cell is configured to rupture along the weak area when the internal pressure of the battery cell reaches a threshold, so as to release the internal pressure. The maximum thickness of the reinforcing portion is greater than the maximum thickness of the main body portion, so as to reduce the deformation of the reinforcing portion under the action of the internal pressure.

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