Battery monomer, battery and electric device

Abstract

The utility model discloses a battery monomer, a battery and a power utilization device, the battery monomer comprises: an electrode assembly, which comprises at least one positive pole piece and at least one negative pole piece, and the at least one positive pole piece and the at least one negative pole piece are stacked to form a straight area, at least one part of the positive pole piece and at least one part of the negative pole piece are stacked in the straight area along the first direction; a case for accommodating the electrode assembly, the case including a first wall portion; the pressure relief component is arranged on the first wall part, a first nick groove is formed in the pressure relief component, and the pressure relief component is configured to be capable of cracking along at least one part of the first nick groove when the battery monomer is subjected to pressure relief; wherein the first nick groove comprises a first groove section extending along a linear track, the length direction of the first groove section is perpendicular to the first direction, the size W of the groove bottom surface of the first groove section in the first direction is larger than or equal to 0.3 mm and smaller than or equal to 0.8 mm. According to the battery monomer provided by the embodiment of the invention, the probability of low-cycle fatigue phenomenon can be reduced to a certain extent.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to a battery cell, a battery, and an electrical device. Background Art

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0003] In order to ensure the safety performance of battery cells, a pressure relief component is usually provided on the battery cells. The pressure relief component is used to release the pressure inside the battery cells when the battery cells reach predetermined conditions. During the charging and discharging process of the battery cells, the electrode assemblies will expand and deform, causing the outer shell containing the electrode assemblies to swell and deform, which in turn makes the pressure relief component provided on the outer shell prone to damage, reducing the reliability of the battery cells. Utility Model Content

[0004] In view of the above problems, the present application provides a battery cell, a battery and an electrical device, which can alleviate the problem of damage to the pressure relief component during battery use.

[0005] In the first aspect, the present application provides a battery cell, comprising: an electrode assembly, comprising at least one positive electrode sheet and at least one negative electrode sheet, the at least one positive electrode sheet and the at least one negative electrode sheet are stacked to form a flat area, at least a portion of the positive electrode sheet and at least a portion of the negative electrode sheet are stacked along a first direction in the flat area; a shell, for accommodating the electrode assembly, the shell comprising a first wall portion; a pressure relief component, arranged on the first wall portion, the pressure relief component is provided with a first notch groove, the pressure relief component is configured to be able to split along at least a portion of the first notch groove when the battery cell is depressurized; wherein the first notch groove comprises a first groove segment extending along a straight trajectory, the length direction of the first groove segment is perpendicular to the first direction, and the size of the groove bottom surface of the first groove segment in the first direction is W, 0.3mm≤W≤0.8mm.

[0006] In the technical solutions of the embodiments of the present application, by limiting the size of the bottom surface of the first slot segment, it is possible to reduce the occurrence of damage, cracking, and leakage in the weakest area of ​​the first slot segment due to expansion and deformation of the electrode assembly, thereby reducing the probability of low-cycle fatigue and improving the reliability of the battery cell. At the same time, it ensures uniform material flow during the manufacturing process, improves the appearance qualification rate, reduces manufacturing defects, and improves the manufacturing quality of the product. In some embodiments, the pressure relief component is welded to the first wall portion and mounted on the first wall portion. The dimension W of the bottom surface of the first slot segment in the first direction satisfies the following conditions: 0.4 mm ≤ W ≤ 0.75 mm, and optionally, 0.44 mm ≤ W ≤ 0.65 mm. In the above technical solutions, it is possible to reduce the occurrence of damage, cracking, and leakage in the weakest area of ​​the first slot segment due to expansion and deformation of the electrode assembly, thereby reducing the probability of low-cycle fatigue and ensuring uniform material flow during the manufacturing process, improving the appearance qualification rate, reducing manufacturing defects, and improving the manufacturing quality of the product.

[0007] In some embodiments, the width of the first wall portion along the first direction is D, satisfying the following conditions: 0.008 ≤ W / D ≤ 0.019, and 20 mm ≤ D ≤ 80 mm. In the above technical solution, the width ratio of the first groove segment to the first wall portion satisfies the above range, which can reduce low-cycle fatigue to a certain extent, reduce manufacturing defects, and improve product manufacturing quality.

[0008] In some embodiments, the first score groove defines at least one predetermined pressure relief area, and the pressure relief component is provided with a second score groove, which is configured to guide at least a portion of the predetermined pressure relief area to flip over, thereby opening at least a portion of the predetermined pressure relief area. In the above technical solution, the second score groove can guide the predetermined pressure relief area to open, thereby improving the opening effect of the predetermined pressure relief area of ​​the pressure relief component, and further increasing the pressure relief rate of the battery cell when thermal runaway occurs, thereby reducing the risk of fire, explosion, connection failure, etc. caused by untimely pressure relief of the battery cell, and thus improving the reliability of the battery cell.

[0009] In some embodiments, the residual thickness of the second score groove is greater than the residual thickness of the first score groove. In the above technical solution, the strength of the pressure relief component in the area where the first score groove is provided can be made weaker than the strength of the area where the second score groove is provided, so that the pressure relief component can preferentially rupture along the first score groove to achieve rapid opening of the predetermined pressure relief area.

[0010] In some embodiments, the maximum width of the second scored groove is no greater than the maximum width of the first scored groove. In the above technical solution, the processing and forming of the second scored groove is facilitated while also, to a certain extent, avoiding the situation where the second scored groove is too strong, making it difficult for the battery cell to release pressure in the predetermined manner, thereby improving the reliability of the battery cell.

[0011] In some embodiments, the first notch groove further includes two second groove segments, the two second groove segments are arranged opposite each other, the two ends of the first groove segment are respectively connected to one end of the two second groove segments, and the other ends of the two second groove segments are connected to the two ends of the second notch groove, and the first groove segment, the two second groove segments, and the second notch groove together define a predetermined pressure relief area. In the above technical solution, the first groove segment and the second notch groove connect the two second groove segments to form an annular structure, so that the intersection of the first groove segment and the second groove segment is weaker and easier to crack and open the predetermined pressure relief area for pressure relief; at the same time, this structure is conducive to increasing the open area of ​​the predetermined pressure relief area, increasing the pressure relief area of ​​the battery cell, and improving the pressure relief rate of the battery cell.

[0012] In some embodiments, the second notched groove is arranged parallel to and opposite to the first groove section, and the second groove section extends along a straight line and / or an arcuate trajectory. In the above technical solution, the second groove section extends along a straight line, which can reduce the difficulty of forming the second groove section; the second groove section extends along an arcuate trajectory, and the second groove section is an arc-shaped groove. As a result, the pressure relief component is more likely to break along the second groove section when the battery cell is depressurized, achieving a faster opening of the predetermined pressure relief area.

[0013] In some embodiments, the pressure relief component has a first surface and a second surface disposed opposite each other along the thickness direction of the first wall portion, and the first score groove and the second score groove are disposed on the first surface. In the above technical solution, the processing and forming of the first score groove and the second score groove are facilitated, thereby improving processing efficiency.

[0014] In some embodiments, the first surface is the surface of the pressure relief component facing the exterior of the housing. The first and second score grooves are disposed on the exterior of the pressure relief component, facilitating the processing of score grooves on the exterior of the battery cell, thereby reducing the difficulty of forming the score grooves and improving the production efficiency of the battery cell.

[0015] In some embodiments, the pressure relief component is integrally formed with the first wall portion, the extension direction of the first slot segment intersects the first direction, and the dimension W of the bottom surface of the first slot segment in the first direction satisfies the following conditions: 0.35 mm ≤ W ≤ 0.5 mm, and optionally, 0.38 mm ≤ W ≤ 0.45 mm. This technical solution can reduce the risk of damage, cracking, and leakage in the weakest area of ​​the first slot segment due to expansion and deformation of the electrode assembly, thereby reducing the probability of low-cycle fatigue. It also ensures uniform material flow during the manufacturing process, improves the appearance qualification rate, reduces manufacturing defects, and improves the manufacturing quality rate of the product.

[0016] In some embodiments, the first scored groove includes a first groove section and a second groove section, the first groove section is connected to the second groove section, and the first groove section and the second groove section jointly define a predetermined pressure relief area. In the above technical solution, the predetermined pressure relief area is jointly defined by the first groove section and the second groove section. The first scored groove structure of this structure is simple, and the stress at the connection point between the first groove section and the second groove section is more concentrated and weaker. This allows the pressure relief component to quickly rupture from the first groove section and the second groove section after rupturing at the connection point between the first groove section and the second groove section during thermal runaway of the battery cell, allowing the predetermined pressure relief area to open more quickly and relieve pressure in a timely manner.

[0017] In some embodiments, the first notch groove includes two first groove segments and one second groove segment, the two first groove segments are arranged opposite each other, the two first groove segments are respectively connected to the second groove segments, the connection position of the second groove segment to each first groove segment deviates from the two ends of the first groove segment, and the two first groove segments and the second groove segment jointly define a predetermined pressure relief area. In the above technical solution, the two first groove segments are connected to the second groove segment, making the intersection of the first groove segment and the second groove segment weaker, making it easier to crack and open the predetermined pressure relief area for pressure relief; the two first groove segments are arranged opposite each other, which can further increase the open area of ​​the predetermined pressure relief area, thereby increasing the pressure relief area of ​​the battery cell and improving the pressure relief rate of the battery cell.

[0018] In some embodiments, the first notch groove includes one first groove segment and two second groove segments, the two second groove segments are arranged opposite each other, the first groove segment connects the two second groove segments, and the connection position of each second groove segment with the first groove segment deviates from the two ends of the corresponding second groove segment. The first groove segment and the two second groove segments jointly define a predetermined pressure relief area. In the above technical solution, the first groove segment connects the two second groove segments, making the intersection of the first groove segment and the second groove segment weaker and more likely to crack and open the predetermined pressure relief area for pressure relief; the two second groove segments are arranged opposite each other, which can further increase the open area of ​​the predetermined pressure relief area, thereby increasing the pressure relief area of ​​the battery cell and improving the pressure relief rate of the battery cell.

[0019] In some embodiments, the first scored groove includes one first groove segment and four second groove segments. The first groove segment is connected at each end to two second groove segments arranged at a preset angle. The first groove segment and the four second groove segments together define a predetermined pressure relief zone. In the above technical solution, the first groove segment connects to the four second groove segments, making the intersection of the first and second groove segments weaker and more likely to rupture and open the predetermined pressure relief zone for pressure relief. This structure also helps increase the open area of ​​the predetermined pressure relief zone, thereby increasing the pressure relief area of ​​the battery cell and improving the pressure relief rate of the battery cell.

[0020] In some embodiments, the first score groove defines at least one predetermined pressure relief area, and the pressure relief component is provided with a second score groove, which is configured to guide at least a portion of the predetermined pressure relief area to flip over, thereby opening at least a portion of the predetermined pressure relief area. In the above technical solution, the second score groove can guide the predetermined pressure relief area to open, thereby improving the opening effect of the predetermined pressure relief area of ​​the pressure relief component, and further increasing the pressure relief rate of the battery cell when thermal runaway occurs, thereby reducing the risk of fire, explosion, connection failure, etc. caused by untimely pressure relief of the battery cell, and thus improving the reliability of the battery cell.

[0021] In some embodiments, the pressure relief component has a first surface and a second surface disposed opposite each other along the thickness direction of the first wall portion, the first score groove being disposed on the first surface, and the second score groove being disposed on the second surface. In the above technical solution, the first score groove and the second score groove are disposed on the first surface and the second surface, respectively, so that the first score groove and the second score groove are located on opposite sides of the pressure relief component in the thickness direction, respectively. This facilitates machining the first score groove and the second score groove on opposite sides of the pressure relief component, which helps to reduce mutual influence between the first score groove and the second score groove during machining.

[0022] In some embodiments, the first surface is the surface of the pressure relief component facing the outside of the shell, and the second surface is the surface of the pressure relief component facing the inside of the shell. In the above technical solution, the first surface is the surface of the pressure relief component facing the outside of the shell, so that the first notch groove is arranged on the outside of the pressure relief component, which is convenient for processing and forming the first notch groove on the outside of the battery cell, which is beneficial to reducing the difficulty of forming the first notch groove and improving the production efficiency of the battery cell. The second surface is the surface of the pressure relief component facing the inside of the shell, so that the second notch groove is arranged on the inside of the pressure relief component. On the one hand, during the process of flipping outward to open the predetermined pressure relief area, the two opposite sides of the second notch groove in the width direction are not easy to abut each other, which is beneficial to increase the opening area of ​​the predetermined pressure relief area; on the other hand, the second notch groove is not exposed to the outside of the battery cell, reducing the risk of oxidation and corrosion of the pressure relief component in the second notch groove area.

[0023] In some embodiments, along the thickness direction of the first wall portion, the pressure relief component has a first surface and a second surface arranged opposite to each other, and the first groove section includes a multi-level groove arranged in sequence from the first surface to the direction close to the second surface, and in two adjacent levels of grooves, the first-level groove far away from the first surface is arranged at the groove bottom surface of the first-level groove close to the first surface; wherein, among the multi-level grooves, the first-level groove farthest from the first surface is the first-level groove, the minimum residual thickness of the first-level groove is the minimum residual thickness of the first groove section, and the groove bottom surface of the first-level groove is the groove bottom surface of the first groove section. In the above technical solution, by arranging the groove sections to arrange the multi-level grooves along the thickness direction of the first wall portion, when forming the groove sections, each level of groove can be processed one by one along the direction from the first surface to the second surface, thereby reducing the forming depth of each level of groove, reducing the forming force applied to the pressure relief component when forming the first notched groove, and reducing the risk of the pressure relief component being damaged when forming the first notched groove.

[0024] In some embodiments, the first score groove is stamped and formed on the pressure relief component. In the above technical solution, the first score groove is stamped and formed on the pressure relief component. The forming method of the first score groove is simple, which is conducive to reducing the production cost of the battery cell.

[0025] In some embodiments, the housing includes: a shell and an end cap, wherein at least one side of the shell has an opening, the end cap is connected to the shell and is used to close the opening, and the first wall portion is formed on the shell. In the above technical solution, by arranging the pressure relief component on the shell, the structure of the end cap can be simplified, and the distance between the pressure relief component and the main body of the electrode assembly can be shortened. This can further shorten the path for the discharge medium to flow to the pressure relief component during pressure relief, shorten the time it takes for the discharge medium to reach the pressure relief component, improve the timeliness of pressure relief of the battery cell, and thus effectively improve the reliability of the battery cell.

[0026] In some embodiments, the housing has openings on opposite sides, and the two end caps are used to close the openings on the corresponding sides. Providing two openings on the housing facilitates the manufacturing and molding of the housing, and also facilitates the extraction of the electrode tabs from both ends of the electrode assembly, thereby facilitating the separation of the two electrical connections and reducing the risk of short circuits in the battery cells.

[0027] In some embodiments, the first wall portion is used to support the electrode assembly and is located below the electrode assembly. In the above technical solution, the pressure relief component can be provided at the bottom of the battery cell, and the bottom of the battery cell can be provided with an exhaust channel, which can be connected to the pressure relief portion to discharge high-temperature and high-pressure flue gas through the pressure relief component at the bottom into the exhaust channel and then to the outside when thermal runaway of the battery cell occurs.

[0028] In a second aspect, the present application provides a battery comprising the battery cell in the above embodiment.

[0029] In a third aspect, the present application provides an electrical device, which includes the battery in the above embodiment, and the battery is used to provide electrical energy to the electrical device.

[0030] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0032] Figure 1 is a schematic diagram of an electrical device in the related art;

[0033] Figure 2 A schematic diagram of a battery in the related art;

[0034] Figure 3 A schematic diagram of a battery cell provided in some embodiments of the present application;

[0035] Figure 4 An exploded view of a battery cell provided in some embodiments of the present application;

[0036] Figure 5 A schematic diagram of an electrode assembly provided in some embodiments of the present application;

[0037] Figure 6 Schematic diagrams of electrode assemblies provided in other embodiments of the present application;

[0038] Figure 7 A schematic diagram of a housing provided for some embodiments of the present application;

[0039] Figure 8 for Figure 7 a bottom view of the housing shown;

[0040] Figure 9 For the Figure 8 Cross-sectional view along line AA;

[0041] Figure 10 for Figure 9 The middle circle shows an enlarged view of B;

[0042] Figure 11 for Figure 10 The middle circle shows an enlarged view of C;

[0043] Figure 12 A schematic diagram of a pressure relief component provided in some embodiments of the present application;

[0044] Figure 13 For the Figure 12 Cross-sectional view along the mid-DD line;

[0045] Figure 14 for Figure 13 The middle circle shows an enlarged view of E;

[0046] Figure 15 Schematic diagrams of pressure relief components provided in other embodiments of the present application;

[0047] Figure 16 Schematic diagrams of pressure relief components provided in some other embodiments of the present application;

[0048] Figure 17 Schematic diagram of a pressure relief component provided in some embodiments of the present application installed on a first wall portion.

[0049] Reference numerals:

[0050] Battery 1000, vehicle 2000, battery cell 100, housing 200, first portion 201, first portion 202,

[0051] Housing 10, shell 101, end cover 102, first wall portion 11, second wall portion 12,

[0052] Electrode assembly 20, positive electrode sheet 21, negative electrode sheet 22, straight area 23, turning area 24,

[0053] Electrical connection portion 30,

[0054] Pressure relief component 40, predetermined pressure relief area 401, first surface 40a, second surface 40b,

[0055] First notch groove 41, first groove section 411, first level groove 4111, second groove section 412, first straight line segment 413, second straight line segment 414, arc segment 415, third straight line segment 416, second notch groove 42,

[0056] Patch 60. DETAILED DESCRIPTION

[0057] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0058] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0059] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0060] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0061] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0062] The term "plurality" used in this application refers to two or more (including two).

[0063] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0064] The battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present application.

[0065] The battery mentioned in the embodiments of the present application may include one or more battery cells to provide a single physical module with higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, in parallel or in hybrid through a busbar.

[0066] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0067] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0068] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0069] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0070] The development of battery technology must take into account multiple design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, the safety performance of the battery also needs to be considered.

[0071] In a battery cell, to ensure the safety performance of the battery cell, a pressure relief component may be provided on the outer shell of the battery cell. When the battery cell experiences thermal runaway, the pressure inside the battery cell is released through the pressure relief component to improve the safety of the battery cell.

[0072] During the charging and discharging process of the battery cell, the electrode assembly will expand, causing the shell to swell and deform. The expansion of the shell will be transmitted to the surface of the pressure relief component, causing the surface of the pressure relief component to become concave and stretched, especially in the direction of greater expansion of the electrode assembly. The notched groove will produce a large strain. The battery cell has a large expansion force when fully charged and a small expansion force when discharged. There is a large expansion force amplitude during long-term charging and discharging. Coupled with the gas production inside the battery cell and different external constraints, the notched groove will produce a large strain and strain amplitude, which will lead to low-cycle fatigue of the pressure relief component. The battery cell is prone to cracking, failure and leakage of the pressure relief component before the warranty conditions are met.

[0073] In view of this, an embodiment of the present application provides a battery cell, comprising: an electrode assembly, comprising at least one positive electrode sheet and at least one negative electrode sheet, wherein the at least one positive electrode sheet and the at least one negative electrode sheet are stacked to form a flat area, and at least a portion of the positive electrode sheet and at least a portion of the negative electrode sheet are stacked along a first direction in the flat area; an outer shell for accommodating the electrode assembly, the outer shell comprising a first wall portion; the battery cell further comprising a pressure relief component, the pressure relief component being arranged on the first wall portion, the pressure relief component being provided with a first notch groove, and the pressure relief component being configured to be able to split along at least a portion of the first notch groove when the battery cell is depressurized.

[0074] Among them, the first scoring groove includes multiple groove segments, and the multiple groove segments include at least the first groove segment. Along the thickness direction of the first wall portion, the minimum residual thickness of the first groove segment is less than or equal to the minimum residual thickness of other groove segments, and the size of the groove bottom surface of the first groove segment in the first direction is not less than 0.15 mm.

[0075] In such a battery cell, by limiting the size of the bottom surface of the first slot segment, it is possible to reduce the risk of damage, cracking, and leakage in the weakest area of ​​the first slot segment due to expansion and deformation of the electrode assembly, thereby reducing the probability of low-cycle fatigue to a certain extent and improving the reliability of the battery cell.

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

[0077] Electrical devices may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and electric tools, etc. Vehicles may include fuel vehicles, gas vehicles, or new energy vehicles. New energy vehicles may include pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. 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, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

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

[0079] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 2000 provided in some embodiments of the present application. A battery 1000 is disposed within vehicle 2000, and battery 1000 can be located at the bottom, front, or rear of vehicle 2000. Battery 1000 can be used to power vehicle 2000, for example, as an operating power source for vehicle 2000.

[0080] The vehicle 2000 may further include a controller and a motor. The controller is used to control the battery 1000 to power the motor, for example, to meet the power requirements of the vehicle 2000 during starting, navigation, and driving.

[0081] In some embodiments of the present application, the battery 1000 can not only serve as the operating power source of the vehicle 2000, but also serve as the driving power source of the vehicle 2000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 2000.

[0082] Please refer to Figure 2 , Figure 2 This is an exploded view of a battery 1000 provided in some embodiments of the present application. The battery 1000 includes a battery cell 100 and a housing 200 , wherein the housing 200 is used to accommodate the battery cell 100 .

[0083] The housing 200 is a component that houses the battery cells 100 and provides storage space for the battery cells 100. The housing 200 can have various structures. In some embodiments, the housing 200 can include a first portion 201 and a second portion 202, which overlap to define a storage space for the battery cells 100. The first portion 201 and the second portion 202 can have various shapes, such as a rectangular parallelepiped or a cylinder. The first portion 201 can be a hollow structure with one side open, and the second portion 202 can be a hollow structure with one side open. The open side of the second portion 202 overlaps the open side of the first portion 201, forming the housing 200 with storage space. Alternatively, the first portion 201 can be a hollow structure with one side open, and the second portion 202 can be a plate-like structure. The second portion 202 overlaps the open side of the first portion 201, forming the housing 200 with storage space. As an example, the battery cell 100 can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell 100 of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a polygonal battery, and a polygonal battery such as a hexagonal battery, etc. There is no special limitation in this application.

[0084] In the battery 1000, there can be one or more battery cells 100. If there are multiple battery cells 100, the multiple battery cells 100 can be connected in series, parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 100. Multiple battery cells 100 can be connected in series, parallel, or in a hybrid connection to form a battery module, which is then connected in series, parallel, or in a hybrid connection to form a whole and housed within the housing 200. Alternatively, all battery cells 100 can be directly connected in series, parallel, or in a hybrid connection, and then the whole battery module 100 can be housed within the housing 200.

[0085] Please refer to Figure 3 and Figure 4 , Figure 3 A schematic diagram of a battery cell 100 provided in some embodiments of the present application; Figure 4 The exploded view of the battery cell 100 provided in some embodiments of the present application is as follows. The battery cell 100 may include a housing 10 and an electrode assembly 20.

[0086] The housing 10 is used to house the electrode assembly 20 and other components such as the electrolyte. The housing 10 may be a steel shell, an aluminum shell, a plastic shell (e.g., polypropylene), a composite metal shell (e.g., a copper-aluminum composite shell), or an aluminum-plastic film. For example, the housing 10 may include a shell 101 and an end cap 102.

[0087] The housing 101 may be a hollow structure with an opening at one end, or may be a hollow structure with openings at two opposite ends. The housing 101 may be made of a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, and the like.

[0088] The end cap 102 is a component that closes the opening of the shell 101 to isolate the internal environment of the battery cell 100 from the external environment. The end cap 102 and the shell 101 together define a storage space for accommodating the electrode assembly 20, electrolyte and other components. The end cap 102 can be connected to the shell 101 by welding or rolling to close the opening of the shell 101. The shape of the end cap 102 can be adapted to the shape of the shell 10. For example, the shell 101 is a rectangular parallelepiped structure, and the end cap 102 is a rectangular plate structure adapted to the shell 10. The material of the end cap 102 can also be various, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0089] In the battery cell 10, there can be one or two end caps 102. In embodiments where the housing 101 is a hollow structure with openings at both ends, two end caps 102 can be provided. The two end caps 102 respectively close the two openings of the housing 101, and the two end caps 102 and the housing 101 together define a storage space. In embodiments where the housing 101 is a hollow structure with an opening at one end, there can be one end cap 102 provided. The end cap 102 closes the opening at one end of the housing 101, and the end cap 102 and the housing 101 together define a storage space.

[0090] The electrode assembly 20 includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell 100, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator is placed between the positive and negative electrodes to prevent short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0091] In some embodiments, the positive electrode may be a positive electrode sheet 21 . The positive electrode sheet 22 may include a positive electrode current collector and a positive electrode active material region disposed on at least one surface of the positive electrode current collector. The positive electrode active material region has a positive electrode active material.

[0092] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material region is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0093] In some embodiments, the negative electrode may be a negative electrode sheet 22 , which may include a negative electrode current collector and a negative electrode active material region disposed on at least one surface of the negative electrode current collector.

[0094] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material region is provided on either one or both of the two facing surfaces of the negative electrode current collector.

[0095] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0096] In some embodiments, the electrode assembly 20 further includes a separator disposed between the positive electrode and the negative electrode.

[0097] In some embodiments, the separator is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical and mechanical stability can be selected.

[0098] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0099] In some embodiments, the battery cell 100 further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not specifically limit the type of electrolyte, and the electrolyte may be selected based on needs. The electrolyte may be liquid, gel, or solid.

[0100] In some embodiments, the electrode assembly 20 is a wound structure in which the positive electrode sheet and the negative electrode sheet are wound into a wound structure.

[0101] In some embodiments, the electrode assembly 20 is a laminated structure.

[0102] As an example, a plurality of positive electrode sheets 21 and a plurality of negative electrode sheets 22 may be provided, and the plurality of positive electrode sheets 21 and the plurality of negative electrode sheets 22 may be alternately stacked.

[0103] As an example, a plurality of positive electrode sheets 21 may be provided, and the negative electrode sheet 22 may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0104] As an example, the positive electrode tab 21 and the negative electrode tab 22 are both folded to form a plurality of stacked folded segments.

[0105] As an example, multiple separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0106] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0107] In some embodiments, the shape of the electrode assembly 20 can be flat or polygonal.

[0108] In some embodiments, the electrode assembly 20 is provided with tabs, which can conduct current from the electrode assembly 20. The tabs include a positive tab and a negative tab.

[0109] The battery cell 100 may further include an electrical connector, which may be disposed on the housing 10 and is configured to electrically connect to the tabs of the electrode assembly 20 to output electrical energy from the battery cell 10. The electrical connector and the tabs may be directly connected, for example, by direct welding. The electrical connector and the tabs may also be indirectly connected, for example, through a current collecting member. The current collecting member may be a metal conductor, such as copper, iron, aluminum, steel, or an aluminum alloy.

[0110] like Figure 3 and Figure 4 As shown, taking the shell 101 as an example of a hollow structure with an opening at one end, two electrical connection parts can be provided on the end cover 102, and the two electrical connection parts are respectively a positive electrical connection part and a negative electrical connection part, the positive electrical connection part is electrically connected to the positive electrode ear, and the negative electrical connection part is electrically connected to the negative electrode ear.

[0111] Please refer to Figure 5 and Figure 6 , Figure 5 A schematic diagram of an electrode assembly 20 provided in some embodiments of the present application; Figure 6 Schematic diagram of an electrode assembly 20 provided in some other embodiments of the present application. The electrode assembly 20 includes a positive electrode sheet 21 and a negative electrode sheet 22. The positive electrode sheet 21 includes a positive electrode body and a positive electrode tab. The positive electrode tab extends from one end of the positive electrode body. Most of the positive electrode tab is not coated with positive electrode active material, while most of the positive electrode body is coated with positive electrode active material. The negative electrode sheet 22 includes a negative electrode body and a negative electrode tab. The negative electrode tab extends from one end of the negative electrode body. Most of the negative electrode tab is not coated with negative electrode active material, while most of the negative electrode body is coated with negative electrode active material. The positive electrode body and the negative electrode body constitute the main body of the electrode assembly.

[0112] like Figure 5 As shown, the electrode assembly 20 includes a plurality of electrode sheets arranged in a wound manner. The electrode assembly 20 includes a straight region 23 and a turning region 24 connected to ends of the straight region 23 .

[0113] A plurality of electrode sheets arranged in a wound manner, namely, a positive electrode sheet 21 and a negative electrode sheet 22 are stacked and wound around a set axis to form an electrode assembly 20. The straight area 23 refers to the portion of the electrode sheet extending along the plane after winding; the turning area 24 refers to the portion of the electrode sheet extending along the arc surface after winding, for example Figure 5 As shown, the portion between the front side surface and the rear side surface of the electrode assembly 20 is formed as a straight area 23. The extension direction of the electrode piece in the straight area 23 is the length direction of the straight area 23. Figure 5 As shown, the length dimension of the straight area 23 in the left-right direction is B1, and the left and right ends of the straight area 23 are turning areas 24.

[0114] like Figure 6 As shown, the electrode assembly 120 includes a plurality of electrode sheets arranged in a stacked manner, and the electrode assembly 20 has a flat region 23 .

[0115] A plurality of stacked electrodes, for example, at least one positive electrode 21 and at least one negative electrode 22, are stacked to form an electrode assembly 20. The straight region 23 is formed by stacking at least a portion of the positive electrode 21 and the negative electrode 22. Alternatively, the straight region 23 is formed by stacking at least a portion of the positive electrode 21 and the negative electrode 22. The extension direction of the electrode in the straight region 23 is the length direction of the straight region 23. Figure 6 As shown, the length dimension of the straight area 23 in the left-right direction is B1.

[0116] Please refer to Figure 7-Figure 17 , Figure 7-11 A schematic diagram of a housing 10 provided for some embodiments of the present application; Figure 12-16 A schematic diagram of a pressure relief component 40 provided in some embodiments of the present application; Figure 17 Schematic diagram of a pressure relief component mounted on a first wall portion, provided for some embodiments of the present application. A battery cell 100 according to an embodiment of the present application includes: an electrode assembly 20 and a housing 10, including at least one positive electrode sheet 21 and at least one negative electrode sheet 22, wherein the at least one positive electrode sheet 21 and the at least one negative electrode sheet 22 are stacked to form a flat region 23, with at least a portion of the positive electrode sheet 21 and at least a portion of the negative electrode sheet 22 stacked along a first direction F1 in the flat region 23; the housing 10 is used to accommodate the electrode assembly 20, and the housing 10 includes a first wall portion 11; and the battery cell 100 further includes a pressure relief component 40, which is disposed on the first wall portion 11 and is provided with a first notch 41. The pressure relief component 40 is configured to rupture along at least a portion of the first notch 41 when the battery cell 100 releases pressure.

[0117] The first notched groove 41 includes a first groove section 411 extending along a straight line. The length of the first groove section 411 is perpendicular to the first direction F1. The size of the groove bottom surface of the first groove section 411 in the first direction F1 is W, 0.3mm≤W≤0.8mm.

[0118] The outer shell 10 is the outermost structural component of the battery cell 100 , and contains the electrode assembly 20 and electrolyte.

[0119] The electrode assembly 20 can be a laminated type, that is, multiple pole pieces of the electrode assembly 20 are stacked, and the pole pieces are stacked to form a flat area 23. In the flat area 23, at least a portion of the positive pole piece 21 and the negative pole piece 22 are stacked along the first direction F1, or at least a portion of the positive pole piece 21 and the negative pole piece 22 are stacked along the first direction F1. Therefore, the expansion deformation of the electrode assembly 20 is particularly obvious in the first direction F1.

[0120] The electrode assembly 20 can also be of a wound type. The positive electrode sheet 21 and the negative electrode sheet 22 of the electrode assembly 20 are stacked with the isolation member and then wound to form a straight area 23. In the straight area 23, part of the positive electrode sheet 21 and part of the negative electrode sheet 22 are stacked along the first direction F1. For example, after winding, each layer of the positive electrode sheet 21 and each layer of the negative electrode sheet 22 can be penetrated by an axis extending along the first direction F1, so that the expansion deformation of the electrode assembly 20 is particularly obvious in the first direction F1.

[0121] The outer shell 10 includes a first wall portion 11 and two second wall portions 12. The two second wall portions 12 are respectively located on both sides of the electrode assembly 20 in the first direction F1. Most of the expansion of the electrode assembly 20 will act on the second wall portions 12. The first wall portion 11 is located on one side of the electrode assembly 20 in the second direction F2. The second direction F2 is perpendicular to the first direction F1. The thickness direction of the first wall portion 11 is the second direction F2. A pressure relief component 40 is provided on the first wall portion 11.

[0122] The pressure relief component 40 is a component used to release the internal pressure of the battery cell 100. When the internal pressure of the battery cell 100 reaches a threshold, the discharge medium inside the battery cell 100 is discharged through the pressure relief component 40 to achieve the purpose of pressure relief. The threshold design varies according to different design requirements. The threshold may depend on one or more materials of the positive electrode plate 21, the negative electrode plate 22, the electrolyte and the separator in the battery cell 100.

[0123] When the battery cell 100 is depressurized, it can be split along at least a portion of the first notched groove 41, that is, the first notched groove 411 of the pressure relief component 40 is a weak portion. The first notched groove 41 includes a first groove section 411, which extends along a straight line. The length direction of the first groove section 411 is perpendicular to the first direction F1. Figure 8 and Figure 12 As shown, the first slot segment 411 extends along the third direction F3 , and the dimension W of the slot bottom surface of the first slot segment 411 in the first direction F1 is the width dimension of the slot bottom surface of the first slot segment 411 .

[0124] The first groove section 411 is the weakest area of ​​the pressure relief component 40. Along the thickness direction of the first wall portion 11 (the second direction F2), the first groove section 411 has the minimum residual thickness, and the extension direction of the first groove section 411 is perpendicular to the first direction F1. When the battery cell 100 expands during the charge and discharge process, causing the outer shell 10 to deform, the deformation of the first wall portion 11 is mainly borne by the first groove section 411. Because under the action of the same expansion force, the groove section with a smaller width dimension deforms more than the groove section with a larger width dimension. Therefore, when the size of the groove bottom surface of the first groove section 411 in the first direction F1 is smaller, the ability of the first groove section 411 to withstand deformation in the first direction F1 is weaker. During the long-term charge and discharge process of the battery cell 100, the greater the strain and strain amplitude generated in the first groove section 411, the more likely the pressure relief component 40 will fail due to low-cycle fatigue cracking, and the lower the long-term reliability.

[0125] In addition, during the manufacturing process of the notched groove, the material at the notched position will be squeezed to the surroundings. During the manufacturing process of the first groove section 411, when the groove bottom surface width of the first groove section 411 is larger, more material will be squeezed to the surroundings at the position of the first groove section 411. At this time, the requirements for manufacturing equipment (such as stamping machines) (such as tonnage and precision) will be higher, and the pressure relief component 40 will be more likely to have uneven material flow, resulting in unqualified appearance dimensions or other internal micro-defects, which will further reduce the manufacturing quality rate of the pressure relief component 40.

[0126] For this reason, Figures 9-14 As shown, the bottom surface size W of the first groove section 411 is limited to between 0.3 mm and 0.8 mm. W can be any one of 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, and 0.8 mm, or a range of values ​​between any two of them. This increases the size of the weak area to a certain extent, increases the ability of the first groove section 411 to withstand deformation in the first direction F1, and reduces the deformation of the pressure relief component 40 in the first groove section 411. As a result, during the long-term charge and discharge process of the battery cell 100, it can avoid, to a certain extent, the abnormal opening of the pressure relief component 40 due to low-cycle fatigue caused by the narrowness of the weakest area, reduce the probability of leakage caused by the pressure relief component 40 being pulled and damaged, and improve the reliability of the battery cell 100. At the same time, it makes the material flow uniform during the manufacturing process, improves the appearance qualification rate, reduces manufacturing defects, and improves the manufacturing quality rate of the product.

[0127] In the technical solution of the embodiment of the present application, by limiting the size of the bottom surface of the first groove section 411, the damage, cracking and leakage caused by the expansion and deformation of the electrode assembly 20 in the weakest area of ​​the first groove section 411 can be reduced, the probability of low-cycle fatigue phenomenon is reduced to a certain extent, and the reliability of the battery cell 100 is improved; at the same time, the material flow in the manufacturing process is made uniform, the appearance qualification rate is improved, the defects caused by manufacturing are reduced, and the manufacturing quality rate of the product is improved.

[0128] In order to make the technical problems, technical solutions and beneficial effects solved by the embodiments of the present application clearer, the following will be further described in detail with reference to the embodiments and drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its applications. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0129] Example 1

[0130] 1) Preparation of positive electrode sheet

[0131] The positive electrode active material LiNi0.7Co0.1Mn0.1O2, the conductive agent Super P, and the binder polyvinylidene fluoride (PVDF) are prepared into a positive electrode slurry in N-methylpyrrolidone (NMP), wherein the solid content in the positive electrode slurry is 50wt%, and the mass ratio of LiNi0.7Co0.1Mn0.1O2, Super P, and PVDF in the solid components is 8:1:1. The positive electrode slurry is coated on the upper and lower surfaces of the current collector aluminum foil and dried at 85°C and then cold pressed. Then, the positive electrode sheet is trimmed, cut into pieces, and divided into strips, and then dried under vacuum conditions at 85°C for 4 hours to make a positive electrode sheet.

[0132] 2) Preparation of negative electrode sheet

[0133] Graphite, conductive agent Super P, thickener carboxymethyl cellulose (CMC), and adhesive styrene butadiene rubber (SBR) are mixed evenly in deionized water to prepare a negative electrode slurry, wherein the solid content in the negative electrode slurry is 30wt%, and the mass ratio of graphite, silicon oxide, Super P, CMC and adhesive styrene butadiene rubber (SBR) in the solid components is 88:7:3:2. The negative electrode slurry is coated on the upper and lower surfaces of the current collector copper foil and dried at 85°C, and then cold pressed, trimmed, cut into pieces, and slit, and then dried under vacuum conditions at 120°C for 12 hours to prepare a negative electrode sheet.

[0134] 3) Preparation of electrolyte

[0135] In an argon atmosphere glove box (H2O <0.1ppm, O2 <0.1ppm), the fully dried electrolyte salt LiPF6 was dissolved in a mixed solvent (the mixed solvent included ethylene carbonate (EC) and diethyl carbonate (DEC), and ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed in a mass ratio of 50:50), and after mixing evenly, a liquid electrolyte with a concentration of 1 mol / L was obtained.

[0136] 4) Isolation parts

[0137] A 16 μm polyethylene film was used as a separator.

[0138] 5) Lithium-ion battery preparation

[0139] The positive electrode sheet, separator, and negative electrode sheet are stacked in order, with the separator placed in the middle of the positive and negative electrode sheets to isolate the positive and negative electrodes. The bare battery cell is wound and the tabs are welded. The bare battery cell is placed in an aluminum casing, and the prepared electrolyte is injected into the dried casing. The battery is packaged, allowed to stand, formed, shaped, and capacity tested to complete the preparation of the lithium-ion battery.

[0140] The preparation method of the battery cells in Examples 2-4 and Comparative Examples 1-2 is the same as that in Example 1, wherein a pressure relief component is integrally stamped out on the outer shell, the outer shell is a rectangular parallelepiped structure, the shell shell is a structure with an opening formed at one end, the wall portion of the shell shell opposite to the end cover is the first wall portion, the first wall portion is a rectangular wall portion, the shell shell is made of aluminum alloy, the wall portion of the shell shell opposite to the end cover is the first wall portion, and the first wall portion is provided with a pressure relief component.

[0141] In each embodiment and comparative example, the first groove section with the smallest residual thickness of the first scored groove is measured, and the first groove section extends along the first direction. When measuring the width dimension W of the groove bottom surface of the first groove section in the first direction, the first wall portion is cut along a surface perpendicular to the first direction, and W is measured on the cut surface.

[0142] The difference between the embodiments and the comparative examples is that the width dimensions of the first slot segments in the first direction are different, as shown in Table 1.

[0143] The cycle times of the battery cells 100 (ie, the fatigue failure times of the battery cells 100 ) when the pressure relief components 40 leaked were characterized for the lithium-ion batteries obtained in Examples 1-4 and Comparative Examples 1-2. The characterization results are shown in Table 1.

[0144] The method for measuring the number of fatigue cycles of a battery cell is as follows.

[0145] 1) Prepare a special test fixture. Specifically, the fixture consists of three 10mm steel plates (first steel plate, second steel plate, and third steel plate). Each steel plate can completely cover the large surface of the battery cell. The first steel plate and the third steel plate are located at both ends of the fixture and are fixed by bolts. The second steel plate is located between the first and third steel plates, and the second steel plate is constrained by a guide rail. The second steel plate can only move horizontally in a direction perpendicular to the plane of the steel plate. The battery cell can be installed between the first and second steel plates, and the large surface of the battery cell (the surface with the largest outer surface area of ​​the battery cell) is in contact with the first and second steel plates. A pressure sensor is provided between the second and third steel plates. By adjusting the position of the second steel plate, the initial extrusion force of the second steel plate on the battery cell can be adjusted.

[0146] 2) Fix a battery cell into a dedicated test fixture, ensure that the large surface of the battery cell is in contact with the first and second steel plates, adjust the position of the second steel plate so that the initial extrusion force of the second steel plate on the battery cell is 2000N, and connect the two electrical connection parts of the battery cell to the dedicated battery charging and discharging equipment.

[0147] 3) Place the battery cell and fixture in a constant temperature environment of 35±2℃ and start the test after the battery cell reaches temperature equilibrium.

[0148] 4) The test steps are carried out in accordance with Section 6.4 "Standard Cycle Life" of GBT31484-2015 Cycle Life Requirements and Test Methods for Power Batteries for Electric Vehicles, and the test cycle end condition is changed to "stop the test until damage occurs at the notch groove of the pressure relief component."

[0149] Specifically, test according to the following steps:

[0150] a) Discharge at 1I(A) until the discharge termination condition specified by the enterprise;

[0151] b) Shelved for no less than 30 minutes or under the shelving conditions specified by the enterprise;

[0152] c) Charge in accordance with the method 6.1.1.3 of GBT31484-2015 Cycle Life Requirements and Test Methods for Power Batteries for Electric Vehicles;

[0153] d) Shelving for no less than 30 minutes or under the shelving conditions specified by the enterprise;

[0154] e) Discharge at 1I1(A) to the discharge termination condition specified by the enterprise,

[0155] f) Repeat steps b) to e) until the notch of the pressure relief component breaks and the test is stopped.

[0156] That is, during the test, the pressure relief component of the battery cell is continuously observed until the pressure relief component leaks, and the number of cycles is recorded as the number of fatigue failures of the battery cell. The test results are shown in Table 1 below.

[0157] Table 1

[0158]

[0159] Based on the data of Examples 1-4 and Comparative Examples 1-2, it can be seen that when W is less than 0.3 mm, the number of fatigue failures is too low to meet the life requirements, but when W is greater than 0.8 mm, the manufacturing yield will decrease. Further regulating the size of W within the given range is beneficial to the battery cell 100 having better cycle performance and manufacturing yield.

[0160] like Figure 4 、 12 - Figure 14 、 Figure 17 As shown, in some embodiments, the pressure relief component 40 is welded and fixed to the first wall portion 11, and the pressure relief component 40 is installed on the first wall portion 11. The size of the groove bottom surface of the first groove section 411 in the first direction F1 is W, satisfying: 0.4mm≤W≤0.75mm, optionally, 0.44mm≤W≤0.65mm.

[0161] like Figure 4 、 12 - Figure 14 As shown, the pressure relief component 40 and the shell 10 are two separate components, which are separately molded and then installed together. Specifically, the pressure relief component 40 can be a burst-proof disk, an explosion-proof valve, a safety valve or other components. The pressure relief component 40 can be installed on the first wall portion 11 by bonding, welding or the like. The first wall portion 11 is provided with a through hole, and the pressure relief component 40 is installed in the through hole. When the internal pressure of the battery cell 100 reaches a threshold value, the pressure relief component 40 opens at least part of the through hole, and the exhaust medium inside the battery cell 100 is discharged through the through hole to release the pressure inside the battery cell 100.

[0162] Since the pressure relief component 40 is a component independent of the housing 10 , the pressure relief component 40 and the housing 10 can be produced separately and then assembled, which reduces the production difficulty and increases the efficiency.

[0163] In this split structure, the overall stiffness of the wall portion of the shell 10 (i.e., the first wall portion 11) is relatively small. During the charging and discharging process of the battery cell 100, the greater the deformation of the first wall portion 11 and the pressure relief component 40, the larger the width W of the first notched groove 41 is required, especially the width dimension of the first groove section 411 with a small residual thickness in the first direction F1 needs to be increased.

[0164] At the same time, in the manufacturing process of the split structure, the pressure relief component 40 is manufactured separately. The shape of the notched groove is first punched out with a thin sheet, and then the excess material is cut off to form the pressure relief component 40. During the stamping process, there is less material flow and there is a larger material flow space, so that a larger groove section width can be achieved while meeting the product quality requirements.

[0165] Therefore, the dimension W of the bottom surface of the first groove segment 411 in the first direction F1 is limited to between 0.4 mm and 0.75 mm. W can be any point value among 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, or a range value between any two of them.

[0166] This can reduce the damage, cracking and leakage caused by the expansion and deformation of the electrode assembly 20 in the weakest area of ​​the first groove section 411, reduce the probability of low-cycle fatigue to a certain extent, and at the same time make the flow of materials uniform during the manufacturing process, improve the appearance qualification rate, reduce the defects caused by manufacturing, and improve the manufacturing quality rate of the product.

[0167] In some further examples, 0.44 mm ≤ W ≤ 0.65 mm.

[0168] W can be any one of 0.44mm, 0.45mm, 0.46mm, 0.47mm, 0.48mm, 0.49mm, 0.5mm, 0.51mm, 0.52mm, 0.53mm, 0.54mm, 0.55mm, 0.56mm, 0.57mm, 0.58mm, 0.59mm, 0.6mm, 0.61mm, 0.62mm, 0.63mm, 0.64mm, and 0.65mm, or a range between any two of them.

[0169] This can further reduce the damage, cracking and leakage caused by the expansion and deformation of the electrode assembly 20 in the weakest area of ​​the first groove section 411, reduce the probability of low-cycle fatigue to a certain extent, and at the same time make the flow of materials uniform during the manufacturing process, improve the appearance qualification rate, reduce the defects caused by manufacturing, and improve the manufacturing quality rate of the product.

[0170] like Figure 17 As shown, in some embodiments, the width of the first wall portion 11 along the first direction F1 is D, satisfying: 0.008≤W / D≤0.019, 20 mm≤D≤80 mm.

[0171] In the first direction F1, the width D of the first wall portion 11 is between 20 mm and 80 mm. For example, the width D of the first wall portion 11 is any one of 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, and 80 mm, or a range between any two of them.

[0172] Among them, on a battery cell of a certain size, if W / D is too small, the width W of the first groove section 411 is too small, the ability of the first groove section 411 to withstand deformation in the first direction F1 is weaker, and during the long-term charging and discharging process of the battery cell 100, the strain and strain amplitude generated in the first groove section 411 are greater, the pressure relief component 40 is more likely to fail due to low-cycle fatigue cracking, and the long-term reliability is lower; if W / D is too large, the width W of the first groove section 411 is too large, the pressure relief component 40 is more likely to have uneven flow, resulting in unqualified appearance dimensions or other internal micro-defects, which in turn will lead to a reduction in the manufacturing quality rate of the pressure relief component 40.

[0173] To this end, W / D can be limited to between 0.008 and 0.019. W / D can be any point value among 0.008, 0.009, 0.01, 0.011, 0.012, 0.013, 0.014, 0.015, 0.016, 0.017, 0.018, 0.019, or a range value between any two of them.

[0174] This can reduce the damage, cracking and leakage caused by the expansion and deformation of the electrode assembly 20 in the weakest area of ​​the first groove section 411, reduce the probability of low-cycle fatigue to a certain extent, and at the same time make the flow of materials uniform during the manufacturing process, improve the appearance qualification rate, reduce the defects caused by manufacturing, and improve the manufacturing quality rate of the product.

[0175] Please refer to Figure 12 and Figure 13In some embodiments, the first score groove 41 defines at least one predetermined pressure relief area 401, and the pressure relief component 40 is provided with a second score groove 42. The second score groove 42 is configured to guide the rotation of at least a portion of the predetermined pressure relief area 401, thereby opening at least a portion of the predetermined pressure relief area 401. The second score groove 42 is a rotation notch provided on the pressure relief component 40. When the pressure relief component 40 is ruptured along at least a portion of the first score groove 41, the second score groove 42 can guide the rotation of at least a portion of the predetermined pressure relief area 401. In other words, the second score groove 42 facilitates the rotation of the predetermined pressure relief area 401, making it easier for the predetermined pressure relief area 401 to rotate toward the outside of the battery cell 100, thereby quickly opening the predetermined pressure relief area 401. The second score groove 42 can guide the rotation of the predetermined pressure relief area 401 in its entirety or in only a portion. During the pressure relief process of the battery cell 100, the pressure relief component 40 can rupture along at least a portion of the first score groove 41, but generally does not rupture along the second score groove 42. Furthermore, after the first score groove 41 ruptures, the predetermined pressure relief area 401 can be flipped around the second score groove 42, so that the interior and exterior of the housing 10 can be interconnected after the predetermined pressure relief area 401 flips, allowing pressure relief to proceed. The minimum thickness of the remaining portion of the pressure relief component 40 in the area where the first score groove 41 is located can be smaller than the minimum thickness of the remaining portion of the pressure relief component 40 in the area where the second score groove 42 is located, making the area where the first score groove 41 is located easier to rupture than the area where the second score groove 42 is located. The second score groove 42 can be formed in various ways, such as by stamping or milling. The second score groove 42 can have various shapes, such as a groove extending along an arcuate trajectory or a groove extending along a straight trajectory. The cross-section of the second scoring groove 42 can have various shapes, such as a rectangle, a trapezoid, etc.

[0176] By providing the second notched groove 42, the predetermined pressure relief area 401 can be guided to open, thereby improving the opening effect of the predetermined pressure relief area 401 of the pressure relief component 40, and further improving the pressure relief rate of the battery cell 100 when thermal runaway occurs, thereby reducing the risk of fire, explosion, connection failure, etc. caused by untimely pressure relief of the battery cell 100, which is beneficial to improving the reliability of the battery cell 100.

[0177] In some embodiments, the maximum width of the second score groove 42 is no greater than the maximum width of the first score groove 41 .

[0178] Since the first score groove 41 needs to withstand greater pressure and serve as the main pressure relief path when the battery cell 100 is depressurized, the maximum width of the second score groove 42 can be appropriately reduced.

[0179] In addition, during the manufacturing process of the second score groove 42, the same manufacturing method as the first score groove 41 can be adopted, for example, a stamping process is adopted. When manufacturing a score groove with a large residual thickness, a corresponding score groove with a small width can be formed, thereby forming a second score groove 42 with a narrower size and a larger residual thickness.

[0180] Therefore, the above arrangement not only facilitates the processing and forming of the second scoring groove 42 , but also avoids to a certain extent the situation where the strength of the second scoring groove 42 is too high, which makes it difficult for the battery cell 100 to release pressure in a predetermined manner, thereby improving the reliability of the battery cell 100 .

[0181] In some embodiments, the residual thickness of the second score groove 42 is greater than the residual thickness of the first score groove 41 .

[0182] The minimum residual thickness of the second scored groove 42 is the minimum thickness of the remaining portion of the pressure relief component 40 after the second scored groove 42 is provided. The remaining portion may be the bottom wall of the second scored groove 42. The thickness of the bottom wall of the second scored groove 42 may be uniform or uneven. If the thickness of the bottom wall of the second scored groove 42 is uneven, the thickness of the thinnest portion of the bottom wall of the second scored groove 42 is the minimum residual thickness of the second scored groove 42.

[0183] In this embodiment, the strength of the area where the first score groove 41 of the pressure relief component 40 is set can be made smaller than the strength of the area where the second score groove 42 of the pressure relief component 40 is set, so that the pressure relief component 40 can preferentially break along the first score groove 41 to achieve rapid opening of the predetermined pressure relief area 401.

[0184] Please refer to Figure 12 In some embodiments, the first notched groove 41 also includes two second groove sections 412, which are arranged opposite to each other. The first groove section 411 is respectively connected to one end of the two second groove sections 412, and the other ends of the two second groove sections 412 are connected to the two ends of the second notched groove 42. The first groove section 411, the two second groove sections 412 and the second notched groove 42 jointly define a predetermined pressure relief area 401.

[0185] As an example, in Figure 12 In the illustrated embodiment, the first groove segment 411 and the second notched groove 42 are arranged opposite to each other, and the first groove segment 411 and the second notched groove 42 are parallel, the two ends of the first groove segment 411 are respectively connected to the two second groove segments 412, and the two ends of the second notched groove 42 are respectively connected to the two second groove segments 412, and the two second groove segments 412 and the first groove segment 411 and the second notched groove 42 form a closed annular structure; in the second direction F2, the outer edge of the orthographic projection of the annular structure constitutes the predetermined opening boundary of the predetermined pressure relief area 401, that is, the predetermined opening boundary is surrounded by the outer edge of the orthographic projection of the first notched groove 41 and the second notched groove 42 in the second direction F2.

[0186] The first groove section 411 and the second notch groove 42 extend along a straight line. Figure 12 As shown, the first groove segment 411 and the second notched groove 42 extend along the third direction F3. In the first direction F1, the width dimension of the groove bottom surface of the first groove segment 411 is W, and 0.3 mm≤W≤0.8 mm.

[0187] The second slot section 412 can extend along a straight trajectory, for example, along the first direction F1, thereby forming a square predetermined pressure relief area 401; the second slot section 412 can also extend along an arc trajectory, thereby forming a runway-shaped predetermined pressure relief area 401.

[0188] In this embodiment, the first groove section 411, the second notched groove 42 and the two second groove sections 412 are connected to form an annular structure, so that the intersection of the first groove section 411 and the second groove section 412 is weaker and easier to crack and open the predetermined pressure relief area 401 for pressure relief; at the same time, this structure is conducive to increasing the opening area of ​​the predetermined pressure relief area 401, increasing the pressure relief area of ​​the battery cell 100, and improving the pressure relief rate of the battery cell 100.

[0189] In some embodiments, the second scoring groove 42 is parallel to and opposite to the first groove segment 411 , and the second groove segment extends along a straight line and / or an arc trajectory.

[0190] In some examples, the length of the second notched groove 42 is the same as that of the first groove segment 411 , the second groove segment 412 is a straight groove, the second groove segment 412 is perpendicular to the first groove segment 411 , and the second groove segment 412 extends along a straight line, which can reduce the difficulty of forming the second groove segment 412 .

[0191] In some examples, the length of the second notched groove 42 is the same as that of the first groove section 411, and the second groove section 412 extends along an arc trajectory. The second groove section 412 is an arc-shaped groove. Therefore, the pressure relief component 40 is more likely to break along the second groove section 412 when the battery cell 100 is depressurized, thereby achieving a faster opening of the predetermined pressure relief area 401.

[0192] In some examples, the length of the second notched groove 42 is smaller than the length of the first groove segment 411, and each second groove segment includes two parts, one part extending along an arc and the other part extending along a straight line, thereby forming an annular structure. The length of the second notched groove 42 is shortened to a certain extent, and the length of the first notched groove 41 is increased, which is conducive to the faster opening of the predetermined pressure relief area 401.

[0193] like Figure 12-14As shown, in some embodiments, along the thickness direction of the first wall portion 11 , the pressure relief component 40 has a first surface 40 a and a second surface 40 b that are oppositely disposed, and the first notch groove 41 and the second notch groove 42 are both disposed on the first surface 40 a .

[0194] The thickness direction of the first wall portion 11 is as follows Figure 13 In the second direction F2 shown, one of the first surface 40a and the second surface 40b can be the outer surface of the pressure relief component 40, and the other can be the inner surface of the pressure relief component 40. The outer surface of the pressure relief component 40 faces the exterior of the battery cell 100, and the inner surface of the pressure relief component 40 faces the interior of the battery cell 100. The first surface 40a and the second surface 40b can be planes, and the first surface 40a and the second surface 40b can be parallel or at a non-zero angle. The first notch 41 and the second notch 42 are provided on the first surface 40a, i.e., the two notches are recessed from the first surface toward the second surface, and the notches are formed on the first surface 40a.

[0195] In this embodiment, the first notched groove 41 and the second notched groove 42 are both disposed on the first surface 40 a , which facilitates the processing and forming of the first notched groove 41 and the second notched groove 42 and improves processing efficiency.

[0196] like Figure 9 and Figure 10 As shown, in some embodiments, the first surface 40 a is a surface of the pressure relief component 40 facing the outside of the housing 10 .

[0197] It can be understood that the first surface 40 a is the outer surface of the pressure relief component 40 . When the pressure relief component 40 is installed on the first wall portion 11 , the first surface 40 a is the outer surface of the first wall portion 11 .

[0198] The first surface 40a is the surface of the pressure relief component 40 facing the outside of the shell, so that the first notched groove 41 and the second notched groove 42 are arranged on the outside of the pressure relief component 40, which is convenient for processing and forming the first notched groove 41 and the second notched groove 42 on the outside of the battery cell 100, and is beneficial to reducing the difficulty of forming the first notched groove 41 and the second notched groove 42, thereby improving the production efficiency of the battery cell 100.

[0199] like Figure 7-11 As shown, in some embodiments, the pressure relief component 40 is integrally formed with the first wall portion 11, the extension direction of the first groove segment 411 is perpendicular to the first direction F1, and the size of the groove bottom surface of the first groove segment 411 in the first direction F1 is W, satisfying: 0.3mm≤W≤0.5mm, optionally, 0.35mm≤W≤0.45mm.

[0200] like Figure 7-11As shown, the pressure relief component 40 is integrally formed with the first wall portion 11, and the first notch groove 41 can be directly set on the first wall portion 11 to form an integrated structure. The first wall portion 11 forms a weak area in the area where the first notch groove 41 is set. The molding method of the pressure relief component 40 is simple, and the connection process between the pressure relief component 40 and the first wall portion 11 is omitted, which can reduce the production and manufacturing cost of the battery cell 100.

[0201] Among them, in the integrated structure, the overall rigidity of the wall portion of the shell 10 (i.e., the first wall portion 11) is large. During the long-term charging and discharging use of the battery cell 100, the deformation degree of the first wall portion 11 is small, so the width dimension of the first groove section 411 can be relatively small, especially the width dimension of the first groove section 411 in the first direction F1 can be relatively small.

[0202] However, the manufacturing of the scored groove usually adopts a stamping process. During the manufacturing process of the scored groove, more material will be squeezed to the surroundings at the scored position, especially in the one-piece structure, the stamping area is a closed area, more material flows during the stamping process and the flow space is small. Therefore, during the manufacturing process of the first groove section 411, the larger the groove bottom surface width of the first groove section 411, the more material will be squeezed to the surroundings at the first groove section 411. At this time, the requirements for manufacturing equipment (such as stamping machines) (such as tonnage and precision) will be higher, and the pressure relief component 40 will be more likely to have uneven material flow, resulting in unqualified appearance dimensions or other internal micro-defects, which will further reduce the manufacturing quality rate of the pressure relief component 40.

[0203] Thus, the dimension W of the bottom surface of the first groove segment 411 in the first direction F1 is limited to between 0.3 mm and 0.5 mm. W can be any one of 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, and 0.5 mm, or a range between any two of them.

[0204] This can reduce the damage, cracking and leakage caused by the expansion and deformation of the electrode assembly 20 in the weakest area of ​​the first groove section 411, reduce the probability of low-cycle fatigue to a certain extent, and at the same time make the flow of materials uniform during the manufacturing process, improve the appearance qualification rate, reduce the defects caused by manufacturing, and improve the manufacturing quality rate of the product.

[0205] In some further examples, 0.35 mm ≤ W ≤ 0.45 mm.

[0206] W can be any point value among 0.35mm, 0.36mm, 0.37mm, 0.38mm, 0.39mm, 0.4mm, 0.41mm, 0.42mm, 0.43mm, 0.44mm, 0.45mm, or a range value between any two of them.

[0207] This can further reduce the damage, cracking and leakage caused by the expansion and deformation of the electrode assembly 20 in the weakest area of ​​the first groove section 411, reduce the probability of low-cycle fatigue to a certain extent, and at the same time make the flow of materials uniform during the manufacturing process, improve the appearance qualification rate, reduce the defects caused by manufacturing, and improve the manufacturing quality rate of the product.

[0208] Please refer to Figure 7-Figure 16 In some embodiments, the first notched groove 41 includes a first groove section 411 and a second groove section 412 . The first groove section 411 is connected to the second groove section 412 . The first groove section 411 and the second groove section 412 jointly define a predetermined pressure relief area 401 .

[0209] The first groove segment 411 and the second groove segment 412 are two groove segments in the first scored groove 41. The second groove segment 412 can be a linear groove extending along a linear trajectory, or a non-linear groove extending along a non-linear trajectory, for example, an arcuate groove extending along an arcuate trajectory. If the first groove segment 411 and the second groove segment 412 both extend along linear trajectories, the first groove segment 411 and the second groove segment 412 can be arranged at an acute angle, a right angle, or an obtuse angle. The first groove segment 411 and the second groove segment 412 can be connected end-to-end to form a V-shaped, L-shaped, or other structure, and the first groove segment 411 and the second groove segment 412 can also be arranged crosswise. The number of the first groove segment 411 and the second groove segment 412 can be multiple, and the multiple groove segments can be connected to each other to form a U-shape, N-shape, or H-shape, etc.

[0210] In this embodiment, the predetermined pressure relief area 401 is jointly defined by the first groove section 411 and the second groove section 412. The first notched groove 41 of this structure has a simple structure, and the stress at the position where the first groove section 411 and the second groove section 412 are connected is more concentrated and weaker. Therefore, when the battery cell 100 thermally runs away, the pressure relief component 40 can quickly split from the first groove section 411 and the second groove section 412 after the first groove section 411 and the second groove section 412 are connected. This allows the predetermined pressure relief area 401 to open more quickly and release pressure in time.

[0211] Please refer to Figure 15 In some embodiments, the first notched groove 41 includes two first groove sections 411 and one second groove section 412. The two first groove sections 411 are arranged opposite to each other, and the two first groove sections 411 are respectively connected to the second groove sections 412. The connection position of the second groove section 412 and each first groove section 411 deviates from the two ends of the first groove section 411. The two first groove sections 411 and the second groove section 412 jointly define a predetermined pressure relief area 401.

[0212] As an example, in Figure 15In the illustrated embodiment, the two first slot segments 411 and the second slot segment 412 form an I-shaped structure, with the ends of the second slot segments 412 connected to the middle portions of the corresponding first slot segments 411. A first straight line segment 413 is defined between the ends of the two first slot segments 411 located on the same side of the second slot segment 412. The first straight line segment 413 and the outer edge of the orthographic projection of the first slot segment 411 in the second direction F2 constitute the predetermined opening boundary of the predetermined pressure relief area 401. Specifically, the predetermined opening boundary is defined by the connecting line between the multiple ends of the first scored groove 41 and the outer edge of the orthographic projection of a portion of the first scored groove 41 in the second direction. It should be noted that the connection point between the second slot segment 412 and the first slot segment 411 can be located at the midpoint of the first slot segment 411 or offset from the midpoint of the first slot segment 411.

[0213] In which, each first groove segment 411 extends along the third direction F3, and the second groove segment 412 can extend along a straight trajectory. For example, the second groove segment 412 extends along the first direction F1. In the first direction F1, the size of the groove bottom surface of the second groove segment 412 is greater than 0.15 mm, and the width size of the groove bottom surface of the first groove segment 411 is W, 0.15 mm≤W≤0.8 mm.

[0214] In this embodiment, the two first groove sections 411 are connected to the second groove section 412, so that the intersection of the first groove section 411 and the second groove section 412 is weaker and easier to crack and open the predetermined pressure relief area 401 for pressure relief; the two first groove sections 411 are arranged relative to each other, which can further increase the opening area of ​​the predetermined pressure relief area 401, thereby increasing the pressure relief area of ​​the battery cell 100 and improving the pressure relief rate of the battery cell 100.

[0215] Please refer to Figure 8 In some embodiments, the first notched groove 41 includes a first groove section 411 and two second groove sections 412. The two second groove sections 412 are arranged opposite to each other. The first groove section 411 connects the two second groove sections 412. The connection position of each second groove section 412 and the first groove section 411 deviates from the two ends of the corresponding second groove section 412. The first groove section 411 and the two second groove sections 412 jointly define a predetermined pressure relief area 401.

[0216] As an example, in Figure 8In the illustrated embodiment, the first slot segment 411 and the two second slot segments 412 form an H-shaped structure. The ends of the first slot segment 411 are respectively connected to the middle portions of the corresponding second slot segments 412. A second straight segment 414 is defined between the ends of the two second slot segments 412 located on the same side of the first slot segment 411. The second straight segment 414 and the outer edges of the orthographic projections of the second slot segments 412 in the second direction F2 constitute the predetermined opening boundary of the predetermined pressure relief area 401. That is, the predetermined opening boundary is jointly defined by the lines connecting the multiple ends of the first scored groove 41 and the outer edges of the orthographic projections of a portion of the first scored groove 41 in the second direction. It should be noted that the connection point between the second slot segment 412 and the first slot segment 411 can be located at the midpoint of the second slot segment 412 or offset from the midpoint of the second slot segment 412.

[0217] Among them, the first groove segment 411 extends along the third direction F3, and the second groove segment 412 can extend along a straight track. For example, each second groove segment 412 extends along the first direction F1. In the first direction F1, the size of the groove bottom surface of the second groove segment 412 is greater than 0.15 mm, and the width size of the groove bottom surface of the first groove segment 411 is W, 0.15 mm≤W≤0.8 mm.

[0218] In this embodiment, the first groove section 411 connects the two second groove sections 412, so that the intersection of the first groove section 411 and the second groove section 412 is weaker and easier to crack and open the predetermined pressure relief area 401 for pressure relief; the two second groove sections 412 are arranged relative to each other, which can further increase the opening area of ​​the predetermined pressure relief area 401, thereby increasing the pressure relief area of ​​the battery cell 100 and improving the pressure relief rate of the battery cell 100.

[0219] Please refer to Figure 16 In some embodiments, the first notched groove 41 includes a first groove section 411 and four second groove sections 412. The two ends of the first groove section 411 are respectively connected to two second groove sections 412 set at a preset angle. The first groove section 411 and the four second groove sections 412 jointly define a predetermined pressure relief area 401.

[0220] As an example, in Figure 16 In the illustrated embodiment, two second groove sections 412 arranged at a preset angle are respectively connected to the two ends of the first groove section 411; in the second direction F2, an arc section 415 with the vertex of the preset angle as the center is defined between the free ends of the orthographic projections of the two second groove sections 412 located at the same end of the first groove section 411, and a third straight line section 416 is defined between the free ends of the orthographic projections of the two second groove sections 412 located on the same side of the first groove section 411. The two arc sections 415 and the two third straight line sections 416 together constitute a predetermined opening boundary of the predetermined pressure relief area 401, that is, the predetermined opening boundary is surrounded by the connecting lines between the multiple ends of the first notched groove 41.

[0221] The first slot section 411 extends along a straight line. Figure 16 As shown, the first groove section 411 extends along the third direction F3. In the first direction F1, the width dimension of the groove bottom surface of the first groove section 411 is W, and 0.15 mm≤W≤0.8 mm.

[0222] The second slot segments 412 can extend along a straight path. Each second slot segment 412 extends along a square shape that is inclined in the first direction F1. The two second slot segments 412 located at the same end of the first slot segment 411 extend in opposite directions, and the two second slot segments 412 located on the same side of the first slot segment 411 extend in opposite directions. The bottom surface of each second slot segment 412 has a dimension in the first direction F1 that is greater than 0.15 mm.

[0223] In this embodiment, the first slot segment 411 connects the four second slot segments 412, so that the intersection of the first slot segment 411 and the second slot segment 412 is weaker and easier to crack and open the predetermined pressure relief area 401 for pressure relief; at the same time, this structure is conducive to increasing the opening area of ​​the predetermined pressure relief area 401, increasing the pressure relief area of ​​the battery cell 100, and improving the pressure relief rate of the battery cell 100.

[0224] like Figure 8 、 Figure 12 、 Figure 15 、 Figure 16 As shown, in some embodiments, the second slot segment 412 extends along a straight line or an arc trajectory.

[0225] As an example, in Figure 8 、 Figure 15 、 Figure 16 In the illustrated embodiment, the first groove segment 411 and the second groove segment 412 extend along a straight line trajectory. The second groove segment 412 is a straight groove. The second groove segment 412 is perpendicular to the first groove segment 411. The second groove segment 412 extends along a straight line trajectory, which can reduce the difficulty of forming the second groove segment 412.

[0226] exist Figure 12 In the illustrated embodiment, the second groove section 412 extends along an arc trajectory and is an arc-shaped groove. Therefore, the pressure relief component 40 is more likely to break along the second groove section 412 when the battery cell 100 releases pressure, thereby achieving a faster opening of the predetermined pressure relief area 401.

[0227] In some embodiments, the minimum residual thicknesses of the plurality of groove segments of the first scoring groove 41 are the same, thereby facilitating the manufacturing and forming of the plurality of groove segments and reducing the manufacturing difficulty of the first scoring groove 41 .

[0228] Please refer to Figure 9-10 、 Figure 15In some embodiments, the first score groove 41 defines at least one predetermined pressure relief area 401, and the pressure relief component 40 is provided with a second score groove 42, which is configured to guide at least a portion of the predetermined pressure relief area 401 to flip to open at least a portion of the predetermined pressure relief area 401.

[0229] The second score groove 42 is a flip score provided on the pressure relief component 40. When the pressure relief component 40 ruptures along at least a portion of the first score groove 41, the second score groove 42 can guide the flipping of at least a portion of the predetermined pressure relief area 401. In other words, the second score groove 42 facilitates the flipping of the predetermined pressure relief area 401, making it easier for the predetermined pressure relief area 401 to flip toward the outside of the battery cell 100, thereby quickly opening the predetermined pressure relief area 401. The second score groove 42 can guide the flipping of the predetermined pressure relief area 401 in its entirety or only in a portion. During the pressure relief process of the battery cell 100, the pressure relief component 400 can rupture along at least a portion of the first score groove 41, and generally will not rupture along the second score groove 42. The minimum thickness of the remaining portion of the pressure relief component 40 in the area where the first score groove 41 is provided can be smaller than the minimum thickness of the remaining portion of the pressure relief component 40 in the area where the second score groove 42 is provided, so that the area where the pressure relief component 40 in which the first score groove 41 is provided is more susceptible to cracking than the area where the second score groove 42 is provided. The second score groove 42 can be formed in a variety of ways, such as by stamping, milling, etc. The second score groove 42 can have a variety of shapes, such as a groove extending along an arc trajectory, or a groove extending along a straight trajectory. The cross-sectional shape of the second score groove 42 can also be a variety of shapes, such as a rectangle, a trapezoid, etc.

[0230] The second scored groove 42 and the first scored groove 41 may be directly connected, or they may not contact each other. The second scored groove 42 and the first scored groove 41 may be arranged on the same surface of the pressure relief component 40 along the thickness direction of the first wall portion, or they may be arranged on two opposite surfaces of the pressure relief component 40 along the thickness direction of the first wall portion. If the second scored groove 42 and the first scored groove 41 are directly connected, the second scored groove 42 and the first scored groove 41 may be arranged on the same surface of the pressure relief component 40. If the second scored groove 42 and the first scored groove 41 do not contact each other, the projection of the second scored groove 42 and the projection of the first scored groove 41 along the thickness direction of the first wall portion may partially overlap or may not overlap.

[0231] The predetermined pressure relief area 401 is the area of ​​the pressure relief component 40 defined by the first score groove 41. The predetermined pressure relief area 401 defined by the first score groove 41 may be one or more. The predetermined pressure relief area 401 is capable of opening when the pressure relief component 40 is ruptured along the first score groove 41. The predetermined pressure relief areas 401 and the second score grooves 42 may correspond one to one, i.e., each predetermined pressure relief area 401 is provided correspondingly to one second score groove 42. Alternatively, each predetermined pressure relief area 401 is provided correspondingly to multiple second score grooves 42.

[0232] like Figure 10 As shown, in some embodiments, the minimum residual thickness of the second score groove 42 is less than the minimum residual thickness of the first score groove 41 .

[0233] The minimum residual thickness of the second scored groove 42 is the minimum thickness of the remaining portion of the pressure relief component 40 after the second scored groove 42 is provided. The remaining portion may be the bottom wall of the second scored groove 42. The thickness of the bottom wall of the second scored groove 42 may be uniform or uneven. If the thickness of the bottom wall of the second scored groove 42 is uneven, the thickness of the thinnest portion of the bottom wall of the second scored groove 42 is the minimum residual thickness of the second scored groove 42.

[0234] In this embodiment, the strength of the area where the first score groove 41 of the pressure relief component 40 is set can be made smaller than the strength of the area where the second score groove 42 of the pressure relief component 40 is set, so that the pressure relief component 40 can preferentially break along the first score groove 41 to achieve rapid opening of the predetermined pressure relief area 401.

[0235] like Figure 15 As shown, in some embodiments, along the thickness direction of the first wall portion 11 , the projection of the second score groove 42 does not overlap with the projection of the first score groove 41 .

[0236] The thickness direction of the first wall portion 11 is as follows Figure 15 The second direction F2 shown is along the thickness direction of the first wall portion 11, and the projection of the extended line of the second score groove 42 may be connected to the projection of the first score groove 41, or the projection of the extended line of the first score groove 41 may be connected to the projection of the second score groove 42, or the projection of the extended line of the first score groove 41 may be connected to the projection of the extended line of the second score groove 42. The second score groove 42 and the first score groove 41 may be disposed on the same side of the pressure relief component 40 in the thickness direction of the first wall portion, for example, the second score groove 42 and the first score groove 41 may both be disposed on the first surface 40a or the second surface 40b of the pressure relief component 40. The second score groove 42 and the first score groove 41 may also be disposed on different sides of the pressure relief component 40 in the thickness direction of the first wall portion, for example, the first score groove 41 may be disposed on one of the first surface 40a or the second surface 40b of the pressure relief component 40, and the second score groove 42 may be disposed on the other.

[0237] In this embodiment, the projection of the second notched groove 42 along the thickness direction of the first wall portion 11 does not overlap with the projection of the first notched groove 41 along the thickness direction of the first wall portion 11, which can reduce the mutual influence between the first notched groove 41 and the second notched groove 42 during the processing process, and reduce the risk of the first notched groove 41 and the second notched groove 42 being connected to each other during the processing.

[0238] like Figure 10 As shown, in some embodiments, along the thickness direction of the first wall portion 11, the pressure relief component 40 has a first surface 40a and a second surface 40b opposite to each other, the first notch groove 41 is provided on the first surface 40a, and the second notch groove 42 is provided on the second surface 40b.

[0239] The thickness direction of the first wall portion 11 is as follows Figure 10 In the second direction F2 shown, one of the first surface 40a and the second surface 40b can be the outer surface of the pressure relief component 40, and the other can be the inner surface of the pressure relief component 40. The outer surface of the pressure relief component 40 faces the exterior of the battery cell 100, and the inner surface of the pressure relief component 40 faces the interior of the battery cell 100. The first surface 40a and the second surface 40b can be planes, and the first surface 40a and the second surface 40b can be parallel or arranged at a non-zero angle. The first score groove 41 is provided on the first surface 40a, that is, the first score groove 41 is recessed from the first surface 40a toward the second surface 40b, and the notch of the first score groove 41 is formed on the first surface 40a. The second score groove 42 is provided on the second surface 40b, and the second score groove 42 is recessed from the second surface 40b toward the first surface 40a, and the notch of the second score groove 42 is formed on the second surface 40b. It can be understood that the groove section is provided on the first surface 40a, which means that the groove section is recessed from the first surface 40a toward the second surface 40b.

[0240] In this embodiment, the first notched groove 41 and the second notched groove 42 are respectively arranged on the first surface 40a and the second surface 40b, so that the first notched groove 41 and the second notched groove 42 are respectively located on both sides of the pressure relief component 40 in the thickness direction, so as to facilitate the processing of the first notched groove 41 and the second notched groove 42 on both sides of the pressure relief component 40, which is beneficial to reduce the mutual influence of the first notched groove 41 and the second notched groove 42 during the processing.

[0241] like Figure 9 and Figure 10 As shown, in some embodiments, the first surface 40 a is a surface of the pressure relief component 40 facing the outside of the housing 10 , and the second surface 40 b is a surface of the pressure relief component 40 facing the inside of the housing 10 .

[0242] It is understood that the first surface 40a is the outer surface of the pressure relief component 40, and the second surface 40b is the inner surface of the pressure relief component 40. When the pressure relief component 40 is mounted on or integrally formed with the first wall portion 11, the first surface 40a is the outer surface of the first wall portion 11, and the second surface 40b is the inner surface of the first wall portion 11.

[0243] The first surface 40a is the surface of the pressure relief component 40 facing the exterior of the housing. This allows the first score groove 41 to be located on the exterior of the pressure relief component 40, facilitating the formation of the first score groove 41 on the exterior of the battery cell 100. This reduces the difficulty of forming the first score groove 41 and improves the production efficiency of the battery cell 100. The second surface 40b is the surface of the pressure relief component 40 facing the interior of the housing. This allows the second score groove 42 to be located on the interior of the pressure relief component 40. This prevents the second score groove 42 from abutting against the opposing widthwise sides of the predetermined pressure relief area 401 during its outward flipping and opening, thereby increasing the opening area of ​​the predetermined pressure relief area 401. Furthermore, this prevents the second score groove 42 from being exposed to the exterior of the battery cell 100, reducing the risk of oxidation and corrosion of the pressure relief component 40 in the region of the second score groove 42.

[0244] Please refer to Figure 10-11 , Figure 11 for Figure 10 In the enlarged view of the part circled at C, in some embodiments, along the thickness direction of the first wall portion 11, the pressure relief component 40 has a first surface 40a and a second surface 40b arranged opposite to each other, and the first groove section 411 includes a multi-stage groove arranged in sequence from the first surface 40a to the direction close to the second surface 40b, and in the two adjacent grooves, the first-stage groove away from the first surface 40a is arranged at the groove bottom surface of the first-stage groove close to the first surface 40a; wherein, the first-stage groove farthest from the first surface 40a in the multi-stage groove is the first-stage groove 4111, the minimum residual thickness of the first-stage groove 4111 is the minimum residual thickness of the first groove section 411, and the groove bottom surface of the first-stage groove 4111 is the groove bottom surface of the first groove section 411.

[0245] The thickness direction of the first wall portion 11 is the second direction F2, and the groove section can be a two-level groove, a three-level groove, a four-level groove, a five-level groove, etc. It can be understood that the groove section is a stepped groove. Along the direction from the first surface 40a to the second surface 40b, the groove width of each level of the groove gradually decreases. Figure 11 As shown, taking the groove section as a three-level groove as an example, the two-level grooves are respectively the first-level groove 4111, the second-level groove and the third-level groove. During processing, the third-level groove with a larger width can be processed on the first surface 40a first, and then the second-level groove with a slightly smaller width can be processed on the bottom surface of the third-level groove, and then the first-level groove 4111 with an even smaller width can be processed on the bottom surface of the second-level groove.

[0246] The first-stage groove 4111 is the first-stage groove farthest from the first surface 40a in the groove segment. The bottom surface of the first-stage groove 4111 is the bottom surface of the groove segment. The minimum residual thickness of the first-stage groove 4111 is the minimum residual thickness of the groove segment. The maximum distance between the bottom surface of the first-stage groove 4111 and the first surface 40a is equal to the maximum groove depth of the groove segment.

[0247] In this embodiment, by arranging the groove segments into multiple levels of grooves along the thickness direction of the first wall portion 11, each level of grooves can be processed one by one along the direction from the first surface 40a to the second surface 40b when forming the groove segments, thereby reducing the forming depth of each level of grooves, reducing the forming force exerted on the pressure relief component 40 when forming the first notched groove 41, and reducing the risk of the pressure relief component 40 being damaged when forming the first notched groove 41.

[0248] In some embodiments, the first score groove 41 is stamped and formed on the pressure relief component 40 .

[0249] It is understood that the first scored groove 41 is formed in the pressure relief component 40 by stamping. If the first scored groove 41 has a single-stage structure, it can be stamped once to form a groove segment on the pressure relief component 40. If the first scored groove 41 has a multi-stage structure, it can be stamped multiple times, each time forming a single stage, to ultimately form a groove segment after multiple stampings. It is understood that in the embodiment where the pressure relief component 40 is integrally formed with the first wall portion 11, the groove segment is stamped into the first wall portion 11.

[0250] In this embodiment, the first score groove 41 is stamped and formed on the pressure relief component 40 . The forming method of the first score groove 41 is simple, which is beneficial to reducing the production cost of the battery cell 100 .

[0251] like Figure 3 and Figure 4 As shown, in some examples, the housing 10 includes: a shell 101 and an end cover 102 , at least one side of the shell 101 has an opening, the end cover 102 is connected to the shell 101 and is used to close the opening, and the first wall portion 11 is formed on the shell 101 .

[0252] The housing 101 may be a hollow structure with an opening at one end, or may be a hollow structure with openings at two opposite ends. The housing 101 may be in various shapes, such as a prism.

[0253] The end cap 102 is a component that closes the opening of the shell 101 to isolate the internal environment of the battery cell 100 from the external environment. The end cap 102 and the shell 101 together define a storage space for accommodating the electrode assembly 20, the electrolyte and other components. The shape of the end cap 102 can be adapted to the shape of the shell 10. For example, the shell 101 is a rectangular parallelepiped structure, and the end cap 102 is a rectangular plate structure adapted to the shell 10. For another example, the shell 101 is a cylindrical structure, and the end cap 102 is a circular plate structure adapted to the shell 101. The material of the end cap 102 can also be a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc. The material of the end cap 102 and the shell 101 can be the same or different.

[0254] In an embodiment where the housing 101 is open at one end, one end cap 102 may be provided. In an embodiment where the housing 101 is open at two opposite ends, two end caps 102 may be provided, each of which closes the two openings of the housing 101, and the two end caps 102 and the housing 101 together define a receiving space.

[0255] The shell 101 has a first wall portion 11 and a second wall portion 12, and the pressure relief component 40 is arranged on the shell 101. The pressure relief component 40 can be integrally formed with the shell 101, or can be separately arranged from the shell 101. By arranging the pressure relief component 40 on the shell 101, the structure of the end cover 102 can be simplified, and at the same time, it is convenient to shorten the distance between the pressure relief component 40 and the main body of the electrode assembly 20, thereby shortening the path of the discharge medium flowing to the pressure relief component 40 during pressure relief, shortening the time for the discharge medium to reach the pressure relief component 40, and improving the timeliness of the pressure relief of the battery cell 100, thereby effectively improving the reliability of the battery cell 100.

[0256] In some embodiments, two opposite sides of the housing 101 have openings, and the two end covers 102 are used to close the openings on the corresponding sides.

[0257] In an embodiment where the housing 101 has openings at opposite ends, two end covers 102 may be provided. The two end covers 102 respectively close the two openings of the housing 101, and the two end covers 102 and the housing 101 together define a receiving space. The first wall 11 is located on the housing 101, and the pressure relief component 40 is located between the two openings. An electrical connection portion 30 may be provided on each end cover 102. By providing two openings on the housing 101, the manufacturing and forming of the housing 101 can be facilitated, and it is also convenient for the electrode assembly 20 to lead out the tabs from both ends, thereby facilitating the separation and arrangement of the two electrical connections 30, thereby reducing the risk of short circuiting of the battery cell 100.

[0258] The end cap 102 is provided with an electrical connection portion 30 , which is electrically connected to the positive electrode sheet 21 or the negative electrode sheet 22 , thereby being able to input or output electrical energy of the battery cell 100 .

[0259] like Figure 3 and Figure 7 As shown, the first wall portion 11 is used to support the electrode assembly 20 , and the first wall portion 11 is located below the electrode assembly 20 .

[0260] Therefore, the pressure relief component 40 can be arranged at the bottom of the battery cell 100, and an exhaust channel can be provided at the bottom of the battery cell 100. The exhaust channel and the pressure relief component 40 can be connected, so that when the battery cell 100 has thermal runaway, the high-temperature and high-pressure flue gas can be discharged into the exhaust channel through the pressure relief component 40 at the bottom, and then discharged to the outside.

[0261] The battery 1000 according to the second embodiment of the present application includes the battery cell 100 according to the first embodiment of the present application.

[0262] According to an embodiment of the third aspect of the present application, an electrical device includes the battery 1000 according to the embodiment of the second aspect of the present application, and the battery 1000 is used to provide power to the electrical device. Thus, by using the battery 1000, the safety and reliability of the electrical device can be improved.

[0263] Alternatively, as Figure 1 As shown, when battery 1000 is used in a vehicle, it can be installed at the bottom, front, or rear of the vehicle. Battery 1000 can be used to power the vehicle, for example, as an operating power source for the vehicle. The vehicle may also include a controller and a motor. The controller is used to control battery 1000 to power the motor, for example, to meet the vehicle's starting, navigation, and driving needs.

[0264] A battery 1000 and a vehicle having the same according to a specific embodiment of the present application will be described below with reference to the accompanying drawings.

[0265] like Figure 1 As shown, the battery 1000 is located at the bottom of the vehicle and Figure 2 As shown, the battery 1000 includes a plurality of battery cells 100. Figure 3 As shown, each battery cell 100 includes a shell 10 and an electrode assembly 20 . The shell 10 is provided with an electrical connection portion 30 and a pressure relief component 40 . The electrical connection portion 30 and the pressure relief component 40 are located on different sides of the shell 10 . The electrode assembly 20 is arranged in the shell 10 .

[0266] like Figure 3As shown, the housing 10 is generally in the shape of a quadrangular prism, has a simple structure, and is easy to form. The housing 10 has a first wall portion 11, which is located on one side of the electrode assembly 20 in the second direction F2. The first wall portion 11 extends along the third direction F3. The first wall portion 11 is provided with a through hole. The pressure relief component 40 can be installed in the through hole of the first wall portion 11 by bonding, welding, etc. The pressure relief component 40 is a component independent of the housing 10. The pressure relief component 40 and the housing 10 can be manufactured and assembled separately. A patch 60 can also be provided on the outside of the pressure relief component 40. The patch 60 cooperates with the housing 10 to protect the pressure relief component 40.

[0267] like Figure 12-14 As shown, the pressure relief component 40 is provided with a first scoring groove 41 and a second scoring groove 42 , and the residual thickness at the first scoring groove 41 is smaller than the residual thickness at the second scoring groove 42 .

[0268] The pressure relief component 40 is configured to rupture along at least a portion of the first scored groove 41 when pressure is released from the battery cell 100. Specifically, the first scored groove 41 includes a first groove segment 411 and two second groove segments 412. The first groove segment 411 and the second scored groove 42 are disposed opposite each other and extend along the third direction F3. The two second groove segments 412 are disposed opposite each other and form an arc-shaped groove. The two ends of each first groove segment 411 are respectively connected to the two second groove segments 412. The two second groove segments 412, the first groove segment 411, and the second scored groove 42 form a closed annular structure.

[0269] In the first direction F1 , the width of the bottom surface of the first groove section 411 is W, and 0.4 mm ≤ W ≤ 0.75 mm.

[0270] like Figure 7-11 As shown, in other embodiments, the pressure relief component 40 is integrally formed on the first wall portion 11, and the pressure relief component 40 is provided with a first notched groove 41 and a second notched groove 42. The first notched groove 41 includes a first groove section 411 and two second groove sections 412. The ends of the first groove section 411 are respectively connected to the middle parts of the corresponding second groove sections 412. The first groove section 411 extends along the third direction F3, and the second groove section 412 extends along the first direction F1. The first groove section 411 and the two second groove sections 412 form an H-shaped structure.

[0271] Along the thickness direction of the first wall portion 11 (the second direction F2), the pressure relief component 40 has a first surface 40a and a second surface 40b that are arranged opposite to each other, and the first groove section 411 includes a multi-stage groove arranged in sequence from the first surface 40a to the direction close to the second surface 40b. In the two adjacent grooves, the first-stage groove away from the first surface 40a is arranged at the groove bottom surface of the first-stage groove close to the first surface 40a; wherein, the first-stage groove farthest from the first surface 40a in the multi-stage groove is the first-stage groove 4111, the minimum residual thickness of the first-stage groove 4111 is the minimum residual thickness of the first groove section 411, and the groove bottom surface of the first-stage groove 4111 is the groove bottom surface of the first groove section 411.

[0272] The second groove section 412 is also a multi-stage groove. The second groove section 412 has the same shape as the first-stage groove 411 and the minimum residual thickness of the corresponding stage grooves is the same.

[0273] The first scoring groove 41 has a minimum residual thickness at the first groove section 411 , and the minimum residual thickness at the second groove section 412 is equal to the minimum residual thickness at the first groove section 411 .

[0274] In the first direction F1 , the width of the bottom surface of the first groove section 411 is W, and 0.3 mm ≤ W ≤ 0.5 mm.

[0275] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, wherein: include: An electrode assembly comprising at least one positive electrode sheet and at least one negative electrode sheet, wherein the at least one positive electrode sheet and the at least one negative electrode sheet are stacked to form a flat region, and at least a portion of the positive electrode sheet and at least a portion of the negative electrode sheet are stacked along a first direction in the flat region; a housing for accommodating the electrode assembly, the housing comprising a first wall portion; a pressure relief component disposed on the first wall portion, the pressure relief component being provided with a first score groove, and being configured to rupture along at least a portion of the first score groove when the battery cell is pressure-relieved; The first notched groove includes a first groove segment extending along a straight line, the length direction of the first groove segment is perpendicular to the first direction, and the size of the groove bottom surface of the first groove segment in the first direction is W, 0.3mm≤W≤0.8mm.

2. The battery cell according to claim 1, wherein: The pressure relief component is welded and fixed to the first wall portion. The pressure relief component is installed on the first wall portion. The size of the bottom surface of the first groove section in the first direction is W, which satisfies: 0.4mm≤W≤0.75mm, optionally, 0.44mm≤W≤0.65mm.

3. The battery cell according to claim 1 or 2, wherein: The width of the first wall portion along the first direction is D, which satisfies the following conditions: 0.008≤W / D≤0.019, 20 mm≤D≤80 mm.

4. The battery cell according to claim 2, wherein: The first score groove defines at least one predetermined pressure relief area, and the pressure relief component is provided with a second score groove, which is configured to guide at least a portion of the predetermined pressure relief area to flip over to open at least a portion of the predetermined pressure relief area.

5. The battery cell according to claim 4, wherein: The residual thickness of the second scoring groove is greater than the residual thickness of the first scoring groove. The battery cell according to claim 4 , wherein: The maximum width of the second score groove is not greater than the maximum width of the first score groove.

7. The battery cell according to any one of claims 4 to 6, wherein: The first notched groove also includes two second groove sections, which are arranged opposite to each other. The two ends of the first groove section are respectively connected to one end of the two second groove sections, and the other ends of the two second groove sections are connected to the two ends of the second notched groove. The first groove section, the two second groove sections and the second notched groove jointly define a predetermined pressure relief area.

8. The battery cell according to claim 7, wherein: The second notch groove is parallel to and opposite to the first groove segment, and the second groove segment extends along a straight line and / or an arc track.

9. The battery cell according to claim 7, wherein: Along the thickness direction of the first wall portion, the pressure relief component has a first surface and a second surface that are opposite to each other, and the first scoring groove and the second scoring groove are provided on the first surface.

10. The battery cell according to claim 9, wherein: The first surface is a surface of the pressure relief component facing the outside of the housing.

11. The battery cell according to claim 1, wherein The pressure relief component and the first wall portion are integrally formed. The size of the bottom surface of the first groove section in the first direction is W, which satisfies: 0.3mm≤W≤0.5mm, optionally, 0.35mm≤W≤0.45mm.

12. The battery cell according to any one of claims 1 to 2 and 11, wherein: The first scoring groove includes a first groove section and a second groove section, the first groove section is connected to the second groove section, and the first groove section and the second groove section jointly define a predetermined pressure relief area.

13. The battery cell according to claim 12, wherein: The first notched groove includes two first groove sections and one second groove section. The two first groove sections are arranged opposite to each other. The two first groove sections are respectively connected to the second groove sections. The connection position of the second groove section and each first groove section deviates from the two ends of the first groove section. The two first groove sections and the second groove section jointly define a predetermined pressure relief area.

14. The battery cell according to claim 12, wherein: The first notched groove includes one first groove segment and two second groove segments, the two second groove segments are arranged opposite to each other, the first groove segment connects the two second groove segments, the connection position of each second groove segment and the first groove segment deviates from the two ends of the corresponding second groove segment, and the first groove segment and the two second groove segments jointly define a predetermined pressure relief area.

15. The battery cell according to claim 12, wherein: The multiple slot segments include one first slot segment and four second slot segments. The two ends of the first slot segment are respectively connected to two second slot segments set at a preset angle. The first slot segment and the four second slot segments jointly define a predetermined pressure relief area.

16. The battery cell according to any one of claims 11, 13-15, wherein: The first score groove defines at least one predetermined pressure relief area, and the pressure relief component is provided with a second score groove, which is configured to guide at least a portion of the predetermined pressure relief area to flip over to open at least a portion of the predetermined pressure relief area.

17. The battery cell according to claim 16, wherein: Along the thickness direction of the first wall portion, the pressure relief component has a first surface and a second surface that are opposite to each other, the first notch groove is provided on the first surface, and the second notch groove is provided on the second surface.

18. The battery cell according to claim 17, wherein: The first surface is a surface of the pressure relief component facing the outside of the housing, and the second surface is a surface of the pressure relief component facing the inside of the housing.

19. The battery cell according to claim 1, wherein: The pressure relief component has a first surface and a second surface disposed opposite to each other along the thickness direction of the first wall portion, the first groove section includes a plurality of grooves sequentially disposed from the first surface toward the second surface, and in two adjacent grooves, a first groove farther from the first surface is disposed at a groove bottom surface of the first groove closer to the first surface; Among them, the first-level groove farthest from the first surface in the multi-level groove is the first-level groove, the minimum residual thickness of the first-level groove is the minimum residual thickness of the first groove segment, and the groove bottom surface of the first-level groove is the groove bottom surface of the first groove segment.

20. The battery cell according to claim 1, wherein The first notch groove is stamped and formed on the pressure relief component.

21. The battery cell according to claim 1, wherein The housing includes a shell and an end cover. At least one side of the shell has an opening. The end cover is connected to the shell and is used to close the opening. The first wall portion is formed on the shell.

22. The battery cell according to claim 21, wherein Two opposite sides of the shell are each provided with an opening, and the two end covers are used to close the openings on the corresponding sides.

23. The battery cell according to claim 1, wherein The first wall portion is used to support the electrode assembly and is located below the electrode assembly.

24. A battery, wherein: The invention comprises a battery cell according to any one of claims 1 to 23.

25. An electrical device, wherein: The battery according to claim 24 is used to provide electrical energy to the electrical device.

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