Battery monomer, battery and electric device

Abstract

A battery cell (100), a battery (1000) and a power utilization device, the battery cell (100) comprising: an electrode assembly (20) comprising at least one positive pole piece (21) and at least one negative pole piece (22), the at least one positive pole piece (21) and the at least one negative pole piece (22) being stacked and forming a straight region (23), at least one part of the positive pole piece (21) and at least one part of the negative pole piece (22) are stacked in the straight area (23) along the first direction; a case (10) for accommodating the electrode assembly (20), the case (10) comprising a first wall portion (11); a pressure relief member (40) provided on the first wall portion (11), the pressure relief member (40) being provided with a first indented groove (41), the pressure relief member (40) being configured so as to be capable of cracking along at least a portion of the first indented groove (41) when the battery cell (100) is subjected to pressure relief; wherein the first indented groove (41) comprises a first groove section (411) extending along a linear track, the length direction of the first groove section (411) is perpendicular to the first direction, the size W of the groove bottom surface of the first groove section (411) in the first direction is larger than or equal to 0.3 mm and smaller than or equal to 0.8 mm.

Description

Battery cell, battery and electric device TECHNICAL FIELD

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

[0002] Energy saving and emission reduction is the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their energy saving and environmental protection advantages. For electric vehicles, battery technology is an important factor for their development.

[0003] In order to ensure the safety performance of the battery cell, a pressure relief component is usually provided on the battery cell. The pressure relief component is used to release the pressure inside the battery cell when the battery cell reaches a predetermined condition. During the use of charging and discharging, the electrode assembly will swell and deform, causing the shell containing the electrode assembly to also swell and deform, and thus causing the pressure relief component provided on the shell to be easily damaged, reducing the reliability of the battery cell.

[0004] SUMMARY

[0005] In view of the above problems, the present application provides a battery cell, a battery and an electric device, which can alleviate the problem of damage to the pressure relief component during use of the battery.

[0006] In a 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 being stacked and forming a flat area, at least a portion of the positive electrode sheet and at least a portion of the negative electrode sheet being arranged in a first direction in the flat area; a shell for containing the electrode assembly, the shell comprising a first wall portion; a pressure relief component provided on the first wall portion, the pressure relief component being provided with a first notch groove, the pressure relief component being configured to be split along at least a portion of the first notch groove when the battery cell is relieved; wherein the first notch groove comprises a first groove segment extending along a straight trajectory, the length direction of the first groove segment being perpendicular to the first direction, the size of the groove bottom surface of the first groove segment in the first direction being W, 0.3mm≤W≤0.8mm.

[0007] In the technical scheme of the present application, by limiting the size of the groove bottom surface of the first groove segment, the damage and cracking of the thinnest area at the first groove segment due to the swelling and deformation of the electrode assembly can be reduced, the probability of low cycle fatigue phenomenon can be reduced to some extent, and the reliability of the battery cell can be improved. At the same time, the flow of material during manufacturing is uniform, the appearance qualification rate is improved, the defects caused by manufacturing are reduced, and the manufacturing rate of the product is improved.

[0008] In some embodiments, the pressure relief component is welded to the first wall portion, the pressure relief component is mounted to the first wall portion, and a dimension of a groove bottom surface of the first groove segment in the first direction is W, satisfying 0.4mm≤W≤0.75mm, or 0.44mm≤W≤0.65mm. In the above technical solution, the first groove segment can be prevented from being damaged, cracked, or leaking due to expansion and deformation of the electrode assembly, the probability of low-cycle fatigue can be reduced to some extent, the flow of material can be uniform during manufacturing, the appearance qualification rate can be improved, the manufacturing defects can be reduced, and the manufacturing yield of the product can be improved.

[0009] In some embodiments, a width of the first wall portion in the first direction is D, satisfying 0.008≤W / D≤0.019 and 20mm≤D≤80mm. In the above technical solution, the width ratio of the first groove segment and the first wall portion satisfies the above range, the low-cycle fatigue can be reduced to some extent, the manufacturing defects can be reduced, and the manufacturing yield of the product can be improved.

[0010] 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 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. 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 improving the pressure relief rate of the battery monomer when thermal runaway occurs, to reduce the risk of fire explosion, connection failure, and the like due to untimely pressure relief, and to improve the use reliability of the battery monomer.

[0011] In some embodiments, a residual thickness of the second score groove is greater than a residual thickness of the first score groove. In the above technical solution, the strength of the area where the pressure relief component is provided with the first score groove can be less than the strength of the area where the pressure relief component is provided with the second score groove, so that the pressure relief component can preferentially crack along the first score groove to achieve rapid opening of the predetermined pressure relief area.

[0012] In some embodiments, a maximum width of the second score groove is not greater than a maximum width of the first score groove. In the above technical solution, the second score groove can be easily processed and formed, and the strength of the second score groove is not too large to cause the battery monomer to be difficult to relieve pressure in a predetermined manner, thereby improving the reliability of the battery monomer.

[0013] In some embodiments, the first score groove further comprises two second groove segments, the two second groove segments are oppositely arranged, one end of each of the two second groove segments is connected to one end of the first groove segment, and the other end of each of the two second groove segments is connected to one end of the second score groove. The first groove segment, the two second groove segments, and the second score groove together define a predetermined pressure relief area. In the above technical solution, the first groove segment and the second score groove connect the two second groove segments to form a ring-shaped structure, so that the intersection of the first groove segment and the second groove segment is more fragile and more likely to crack and open the predetermined pressure relief area for pressure relief. At the same time, this structure is conducive to increasing the opening area of the predetermined pressure relief area, increasing the pressure relief area of the battery monomer, and improving the pressure relief rate of the battery monomer.

[0014] In some embodiments, the second score groove is parallel and opposite to the first groove segment, and the second groove segment extends along a straight line and / or an arc line. In the above technical solution, the second groove segment extends along a straight line, which can reduce the difficulty of forming the second groove segment. The second groove segment extends along an arc line, and the second groove segment is an arc-shaped groove. Thus, the pressure relief component is more likely to crack along the second groove segment when the battery monomer is relieved, and the predetermined pressure relief area is more quickly opened.

[0015] In some embodiments, along the thickness direction of the first wall portion, the pressure relief component has oppositely arranged first and second surfaces, and the first score groove and the second score groove are arranged on the first surface. In the above technical solution, it is conducive to the processing and forming of the first score groove and the second score groove, and improves the processing efficiency.

[0016] In some embodiments, the first surface is a surface of the pressure relief component facing the outside of the shell. The first score groove and the second score groove are arranged on the outside of the pressure relief component, which facilitates the processing of the score groove on the outside of the battery monomer, and is conducive to reducing the difficulty of forming the score groove to improve the production efficiency of the battery monomer.

[0017] In some embodiments, the pressure relief component is integrally formed with the first wall portion, the extension direction of the first groove segment intersects the first direction, and the size of the groove bottom surface of the first groove segment in the first direction is W, which satisfies 0.35mm≤W≤0.5mm, and optionally, 0.38mm≤W≤0.45mm. In the above technical solution, the damage cracking and leakage at the thinnest area of the first groove segment due to the expansion and deformation of the electrode assembly can be reduced, the probability of low-cycle fatigue phenomenon can be reduced to some extent, the flow of material during manufacturing is uniform, the appearance qualification rate is improved, the manufacturing defects are reduced, and the manufacturing yield of the product is improved.

[0018] In some embodiments, the first score groove comprises the first groove segment and the second groove segment, the first groove segment is connected with the second groove segment, and the first groove segment and the second groove segment jointly define the predetermined pressure relief area. In the above technical solution, the first groove segment and the second groove segment jointly define the predetermined pressure relief area, the first groove segment and the second groove segment are connected at a position where the stress is more concentrated and weaker, so that the pressure relief component can be quickly broken at the position where the first groove segment and the second groove segment are connected when the battery monomer is in thermal runaway, the predetermined pressure relief area can be quickly opened for timely pressure relief.

[0019] In some embodiments, the first score groove comprises two first groove segments and one second groove segment, the two first groove segments are oppositely arranged, the two first groove segments are respectively connected with the second groove segment, and the connection position of the second groove segment and each first groove segment deviates from the two ends of the first groove segment. The two first groove segments and the second groove segment jointly define the predetermined pressure relief area. In the above technical solution, the two first groove segments are connected with the second groove segment, so that the intersection position of the first groove segment and the second groove segment is weaker and more prone to break and open the predetermined pressure relief area for pressure relief; the two first groove segments are oppositely arranged, which can further increase the opening area of the predetermined pressure relief area, thereby increasing the pressure relief area of the battery monomer and improving the pressure relief rate of the battery monomer.

[0020] In some embodiments, the first score groove comprises one first groove segment and two second groove segments, the two second groove segments are oppositely arranged, the first groove segment is connected with 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 the predetermined pressure relief area. In the above technical solution, the first groove segment is connected with the two second groove segments, so that the intersection position of the first groove segment and the second groove segment is weaker and more prone to break and open the predetermined pressure relief area for pressure relief; the two second groove segments are oppositely arranged, which can further increase the opening area of the predetermined pressure relief area, thereby increasing the pressure relief area of the battery monomer and improving the pressure relief rate of the battery monomer.

[0021] In some embodiments, the first score groove comprises one first groove segment and four second groove segments, two of the second groove segments are arranged at a preset included angle at the two ends of the first groove segment, and the first groove segment and the four second groove segments jointly define the predetermined pressure relief area. In the above technical solution, the first groove segment is connected with the four second groove segments, so that the intersection position of the first groove segment and the second groove segment is weaker and more prone to break and open the predetermined pressure relief area for pressure relief; at the same time, this structure is conducive to increasing the opening area of the predetermined pressure relief area, thereby increasing the pressure relief area of the battery monomer and improving the pressure relief rate of the battery monomer.

[0022] 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 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. 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 improving the pressure relief rate of the battery monomer when thermal runaway occurs, so as to reduce the risk of fire explosion, connection failure and the like caused by untimely pressure relief of the battery monomer, and is beneficial to improve the use reliability of the battery monomer.

[0023] In some embodiments, along the thickness direction of the first wall portion, the pressure relief component has oppositely arranged first and second surfaces, the first score groove is arranged on the first surface, and the second score groove is arranged on the second surface. In the above technical solution, the first and second score grooves are arranged on the first and second surfaces respectively, so that the first and second score grooves are respectively located on both sides of the pressure relief component in the thickness direction, so as to facilitate the processing of the first and second score grooves on both sides of the pressure relief component respectively, and is beneficial to reduce the mutual influence of the first and second score grooves during processing.

[0024] In some embodiments, the first surface is a surface of the pressure relief component facing the outside of the shell, and the second surface is a surface of the pressure relief component facing the inside of the shell. In the above technical solution, the first surface is a surface of the pressure relief component facing the outside of the shell, so that the first score groove is arranged on the outside of the pressure relief component, facilitating the processing and forming of the first score groove on the outside of the battery monomer, and is beneficial to reduce the forming difficulty of the first score groove, so as to improve the production efficiency of the battery monomer. The second surface is a surface of the pressure relief component facing the inside of the shell, so that the second score groove is arranged on the inside of the pressure relief component. On the one hand, during the outward flipping and opening process of the predetermined pressure relief area, the two width directionally opposite sides of the second score groove are not easy to abut, which is beneficial to increase the opening area of the predetermined pressure relief area. On the other hand, the second score groove is not exposed to the outside of the battery monomer, reducing the risk of oxidation and corrosion of the pressure relief component in the second score groove area.

[0025] In some embodiments, the pressure relief component has a first surface and a second surface arranged oppositely along the thickness direction of the first wall portion, the first groove section includes a plurality of groove levels arranged in sequence from the first surface to the second surface, and in two adjacent groove levels, a groove level away from the first surface is arranged on the groove bottom surface of a groove level close to the first surface; wherein the groove level farthest away from the first surface is a first groove level, the minimum residual thickness of the first groove level is the minimum residual thickness of the first groove section, and the groove bottom surface of the first groove level is the groove bottom surface of the first groove section. In the above technical solution, by arranging the groove section to have a plurality of groove levels along the thickness direction of the first wall portion, each groove level can be machined in sequence along the direction from the first surface to the second surface when the groove section is formed, thereby reducing the forming depth of each groove level, reducing the forming force on the pressure relief component when the first score groove is formed, and reducing the risk of damage to the pressure relief component when the first score groove is formed.

[0026] In some embodiments, the first score groove is stamp-formed on the pressure relief component. In the above technical solution, the first score groove is stamp-formed on the pressure relief component, the forming method of the first score groove is simple, and the production cost of the battery cell is reduced.

[0027] In some embodiments, the shell includes a shell body having at least one opening on one side and an end cover connected to the shell body and used to close the opening, and the first wall portion is formed on the shell body. In the above technical solution, by arranging the pressure relief component on the shell body, the structure of the end cover can be simplified, and the distance between the pressure relief component and the main body portion of the electrode assembly can be shortened, thereby shortening the path of the discharge medium flowing to the pressure relief portion when the pressure relief occurs, shortening the time for the discharge medium to reach the pressure relief portion, improving the timeliness of the pressure relief of the battery cell, and effectively improving the reliability of the battery cell.

[0028] In some embodiments, the shell has openings on opposite sides, and two end covers are used to close the openings on the corresponding sides. By arranging two openings on the shell body, the manufacturing of the shell body can be facilitated, and the tab of the electrode assembly can be led out from both ends, thereby facilitating the separate arrangement of the two electrical connection portions and reducing the risk of short circuit of the battery cell.

[0029] 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 arranged at the bottom of the battery cell, the bottom of the battery cell can be provided with an exhaust passage, and the exhaust passage and the pressure relief portion can be in communication, so that when the battery cell is in thermal runaway, the high-temperature and high-pressure flue gas can be discharged to the exhaust passage through the pressure relief component at the bottom, and then discharged to the outside.

[0030] In a second aspect, the present application provides a battery including the battery cell in the above embodiments.

[0031] In a third aspect, the present application provides an electric device including the battery in the above embodiments, the battery being configured to provide electric energy for the electric device.

[0032] The above description is merely a summary of the technical solutions of the present application. In order to enable a person skilled in the art to better understand the technical means of the present application and implement the same according to the contents of the description, and in order to enable the above and other purposes, characteristics and advantages of the present application to be more apparent, the following specific embodiments of the present application are described in detail. BRIEF DESCRIPTION OF DRAWINGS

[0033] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not meant to limit the present application. Furthermore, the same reference numerals are used throughout the several views that follow. In the drawings:

[0034] FIG. 1 is a schematic diagram of an electric device in the related art;

[0035] FIG. 2 is a schematic diagram of a battery in the related art;

[0036] FIG. 3 is a schematic diagram of a battery cell according to some embodiments of the present application;

[0037] FIG. 4 is an exploded view of the battery cell according to some embodiments of the present application;

[0038] FIG. 5 is a schematic diagram of an electrode assembly according to some embodiments of the present application;

[0039] FIG. 6 is a schematic diagram of an electrode assembly according to some other embodiments of the present application;

[0040] FIG. 7 is a schematic diagram of a housing according to some embodiments of the present application;

[0041] FIG. 8 is a bottom view of the housing shown in FIG. 7;

[0042] FIG. 9 is a sectional view along line A-A in FIG. 8;

[0043] FIG. 10 is an enlarged view of the encircled B in FIG. 9;

[0044] FIG. 11 is an enlarged view of the encircled C in FIG. 10;

[0045] FIG. 12 is a schematic diagram of a pressure relief component according to some embodiments of the present application;

[0046] FIG. 13 is a sectional view along line D-D in FIG. 12;

[0047] Fig. 14 is an enlarged view of the circle E in Fig. 13;

[0048] Fig. 15 is a schematic view of a pressure relief component according to some embodiments of the present application;

[0049] Fig. 16 is a schematic view of a pressure relief component according to some embodiments of the present application;

[0050] Fig. 17 is a schematic view of a pressure relief component mounted on a first wall portion according to some embodiments of the present application.

[0051] Reference signs:

[0052] Battery 1000, vehicle 2000, battery cell 100, case 200, first portion 201, first portion 202,

[0053] Housing 10, housing 101, end cap 102, first wall portion 11, second wall portion 12,

[0054] Electrode assembly 20, positive electrode tab 21, negative electrode tab 22, flat region 23, curved region 24,

[0055] Electrical connection portion 30,

[0056] Pressure relief component 40, predetermined pressure relief region 401, first surface 40a, second surface 40b,

[0057] First score groove 41, first groove segment 411, first level groove 4111, second groove segment 412, first straight line segment 413, second straight line segment 414, arc segment 415, third straight line segment 416, second score groove 42,

[0058] Patch 60. DETAILED DESCRIPTION

[0059] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the specification herein is for describing particular embodiments only and is not intended to be limiting of the application; the use herein of terms such as "comprise", "comprises", "comprising", "containing", "contain", "contains", "include", "includes", "including", "have", "has", "having", or the like are to be construed as specifying (i.e., "comprising") the stated features, elements and / or components rather than "consisting of" the stated features, elements and / or components such terms will be understood to allow the inclusion of additional features, elements, and / or components within the composition, process, and / or method of this application or claims thereof, so long as those additional features, elements, and / or components do not affect the essence of the application. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

[0061] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily all directed to the same embodiment, or to a common alternative embodiment.

[0062] The term "and / or", within the context of this application, is to be taken as a descriptive main clause of a conjunctive relationship between associated objects, indicating that there can be three kinds of relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this application generally represents an "or" relationship between the associated objects before and after it.

[0063] In the embodiments of the present application, the same reference signs represent the same components, and for the sake of brevity, detailed description of the same components is omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are only exemplary and should not constitute any limitation on the present application.

[0064] "Multiple" appearing in the present application means two or more (including two).

[0065] In the embodiments of the present application, the battery cell can be a secondary battery, which refers to a battery cell that can be used continuously by activating the active material through charging after discharging the battery cell.

[0066] The battery cell can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiments of the present application are not limited thereto.

[0067] The battery referred to in the embodiments of the present application can 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 a hybrid manner through a busbar component.

[0068] In some embodiments, the battery can be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0069] In some embodiments, the battery can be a battery pack, and the battery pack includes a box body and battery cells, and the battery cells or the battery module are accommodated in the box body.

[0070] In some embodiments, the box body can be part of the chassis structure of the vehicle. For example, part of the box body can be at least part of the floor of the vehicle, or part of the box body can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0071] In some embodiments, the battery can be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0072] The development of battery technology needs to consider various design factors, such as performance parameters such as energy density, cycle life, discharge capacity, and charge-discharge rate. In addition, the safety performance of the battery also needs to be considered.

[0073] In the battery cell, in order to ensure the safety performance of the battery cell, a pressure relief component can be provided on the shell of the battery cell. When the battery cell is in thermal runaway, the pressure inside the battery cell is released through the pressure relief component to improve the safety of the battery cell.

[0074] During the use of the battery cell in charging and discharging, the electrode assembly will expand, causing the shell to bulge and deform. The bulging of the shell will be transmitted to the surface where the pressure relief component is located, causing the surface where the pressure relief component is located to be concave and stretched. In particular, in the direction where the electrode assembly expands more, a larger strain will occur at the notch groove. The expansion force of the battery cell is large when it is fully charged and small when it is discharged. In the process of long-term use of charging and discharging, there is a large amplitude of expansion force, coupled with the gas generated inside the battery cell and different external constraint conditions, which will cause a large strain and strain amplitude in the notch groove, thereby causing the pressure relief component to have low-cycle fatigue phenomenon, and the battery cell is prone to have problems such as cracking and failure of the pressure relief component and leakage of liquid before the warranty condition is reached.

[0075] In view of this, the embodiments of the present application provide a battery cell, which includes: an electrode assembly including 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 being stacked to form a flat area, and at least part of the positive electrode sheet and at least part of the negative electrode sheet being arranged in layers in the flat area along a first direction; a shell for accommodating the electrode assembly, the shell including a first wall portion; and a pressure relief component disposed 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 split along at least part of the first notch groove when the battery cell is relieved.

[0076] The first score groove includes a plurality of groove segments, and the plurality of groove segments at least includes a first groove segment. In 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. The size of the groove bottom surface of the first groove segment in the first direction is not less than 0.15 mm.

[0077] In such a battery monomer, by limiting the size of the groove bottom surface of the first groove segment, the damage cracking and leakage at the thinnest area of the first groove segment due to the expansion and deformation of the electrode assembly can be reduced, the probability of low cycle fatigue phenomenon can be reduced to a certain extent, and the reliability of the battery monomer can be improved.

[0078] The technical solutions described in the embodiments of the present application are suitable for batteries and electric devices using the batteries.

[0079] The electric device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, and an electric tool, etc. The vehicle can be a fuel automobile, a gas automobile, or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile, or a range extended automobile, etc. The spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, etc. The electric toy includes a fixed or mobile electric toy, such as a game machine, an electric automobile toy, an electric ship toy, and an electric airplane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool, and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator, and an electric planer, etc. The embodiments of the present application do not specially limit the above electric devices.

[0080] The following embodiments take the electric device as a vehicle for example for convenient description.

[0081] Please refer to FIG. 1, which is a structural schematic diagram of a vehicle 2000 provided by some embodiments of the present application. The vehicle 2000 is internally provided with a battery 1000, which can be arranged at the bottom, the head, or the tail of the vehicle 2000. The battery 1000 can be used for power supply of the vehicle 2000, for example, the battery 1000 can be used as an operating power source of the vehicle 2000.

[0082] The vehicle 2000 can further include a controller and a motor, and the controller is used to control the battery 1000 to supply power to the motor, for example, to meet the working power demand of the vehicle 2000 during starting, navigation, and driving.

[0083] In some embodiments of the present application, the battery 1000 can not only be used as an operating power source of the vehicle 2000, but also be used as a driving power source of the vehicle 2000, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 2000.

[0084] Referring to FIG. 2, FIG. 2 is an exploded view of a battery 1000 according to some embodiments of the present application. The battery 1000 includes a battery cell 100 and a case 200 for accommodating the battery cell 100.

[0085] The case 200 is a component for accommodating the battery cell 100, and provides a placement space for the battery cell 100. The case 200 can have various structures. In some embodiments, the case 200 can include a first part 201 and a second part 202, which are coupled to each other to define a placement space for accommodating the battery cell 100. The first part 201 and the second part 202 can have various shapes, such as a cuboid, a cylinder, etc. The first part 201 can be a hollow structure with one side open, and the second part 202 can also be a hollow structure with one side open. The open side of the second part 202 is coupled to the open side of the first part 201 to form the case 200 with the placement space. Alternatively, the first part 201 can be a hollow structure with one side open, and the second part 202 can be a plate structure. The second part 202 is coupled to the open side of the first part 201 to form the case 200 with the placement space. As an example, the battery cell 100 can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell 100 with other shapes, such as a square battery cell, a blade battery cell, a multi-prismatic battery cell (e.g., a hexagonal battery cell), etc. The present application is not particularly limited.

[0086] In the battery 1000, the battery cell 100 can be one or multiple. If the battery cell 100 is multiple, the multiple battery cells 100 can be connected in series, in parallel, or in a mixed connection. The mixed connection means that the multiple battery cells 100 are connected in series and in parallel. The multiple battery cells 100 can be connected in series, in parallel, or in a mixed connection to form a battery module, and the multiple battery modules can be connected in series, in parallel, or in a mixed connection to form a whole, which is accommodated in the case 200. Alternatively, the multiple battery cells 100 can be directly connected in series, in parallel, or in a mixed connection, and the whole formed by the multiple battery cells 100 is accommodated in the case 200.

[0087] Referring to FIG. 3 and FIG. 4, FIG. 3 is a schematic view of a battery cell 100 according to some embodiments of the present application, and FIG. 4 is an exploded view of the battery cell 100. The battery cell 100 can include a housing 10 and an electrode assembly 20.

[0088] The housing 10 is used to accommodate the electrode assembly 20 and other components such as an electrolyte. The housing 10 can 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, etc. As an example, the housing 10 can include a shell 101 and an end cover 102.

[0089] The shell 101 can be a hollow structure with an opening at one end, or a hollow structure with openings at opposite ends. The shell 101 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0090] 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 cooperates with the shell 101 to define a receiving space for receiving the electrode assembly 20, the electrolyte, and other components. The end cap 102 can be connected to the shell 101 by welding or crimping to close the opening of the shell 101. The shape of the end cap 102 can be adapted to the shape of the outer shell 10, for example, the shell 101 is a cuboid structure, and the end cap 102 is a rectangular plate structure adapted to the outer shell 10. The end cap 102 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0091] In the battery cell 10, the end cap 102 can be one or two. In the embodiment where the shell 101 is a hollow structure with openings at both ends, two end caps 102 can be provided, and the two end caps 102 close the two openings of the shell 101, respectively, and cooperates with the shell 101 to define a receiving space. In the embodiment where the shell 101 is a hollow structure with an opening at one end, one end cap 102 can be provided, and the end cap 102 closes the opening at one end of the shell 101, and one end cap 102 cooperates with the shell 101 to define a receiving space.

[0092] The electrode assembly 20 includes a positive electrode, a negative electrode, and a separator. During charging and discharging of the battery cell 100, active ions (e.g., lithium ions) are inserted and extracted between the positive electrode and the negative electrode. The separator is disposed between the positive electrode and the negative electrode, and can prevent the positive and negative electrodes from short-circuiting while allowing the active ions to pass through.

[0093] In some embodiments, the positive electrode can be a positive electrode tab 21, and the positive electrode tab 22 can 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.

[0094] As an example, the positive electrode current collector has two opposite surfaces in the thickness direction thereof, and the positive electrode active material region is disposed on either one or both of the two opposite surfaces of the positive electrode current collector.

[0095] In some embodiments, the negative electrode can be a negative electrode tab 22, and the negative electrode tab 22 can 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.

[0096] As an example, the negative current collector has two surfaces opposite in the thickness direction thereof, and the negative active material region is provided on either one or both of the two opposite surfaces of the negative current collector.

[0097] In some embodiments, the material of the positive current collector can be aluminum, and the material of the negative current collector can be copper.

[0098] In some embodiments, the electrode assembly 20 further comprises a separator provided between the positive electrode and the negative electrode.

[0099] In some embodiments, the separator is a separator film. The type of the separator film is not particularly limited in the present application, and any known porous structure separator film with good chemical stability and mechanical stability can be used.

[0100] In some embodiments, the separator is a solid-state electrolyte. The solid-state electrolyte is provided between the positive electrode and the negative electrode, and functions to transport ions and separate the positive electrode and the negative electrode.

[0101] In some embodiments, the battery cell 100 further comprises an electrolyte provided between the positive electrode and the negative electrode to function to conduct ions. The type of the electrolyte is not particularly limited in the present application, and can be selected as needed. The electrolyte can be in a liquid state, a gel state, or a solid state.

[0102] In some embodiments, the electrode assembly 20 has a jelly-roll structure. The positive electrode sheet and the negative electrode sheet are wound to form the jelly-roll structure.

[0103] In some embodiments, the electrode assembly 20 has a stack structure.

[0104] As an example, a plurality of positive electrode sheets 21 and a plurality of negative electrode sheets 22 can be provided, and the plurality of positive electrode sheets 21 and the plurality of negative electrode sheets 22 can be alternately stacked.

[0105] As an example, a plurality of positive electrode sheets 21 can be provided, and the negative electrode sheet 22 can be folded to form a plurality of folded sections stacked one on another, and one positive electrode sheet can be interposed between adjacent folded sections.

[0106] As an example, both the positive electrode sheet 21 and the negative electrode sheet 22 can be folded to form a plurality of folded sections stacked one on another.

[0107] As an example, a plurality of separators can be provided, and each of the plurality of separators can be provided between any adjacent positive electrode sheet or negative electrode sheet.

[0108] As an example, a plurality of separators can be provided, and each of the plurality of separators can be provided between any adjacent positive electrode sheet or negative electrode sheet.

[0109] In some embodiments, the electrode assembly 20 can have a flat shape or a polygonal shape.

[0110] In some embodiments, the electrode assembly 20 is provided with tabs, which can lead current out of the electrode assembly 20. The tabs include positive tabs and negative tabs.

[0111] The battery cell 100 can further include an electrical connection portion, which can be provided on the casing 10, for electrically connecting with the tabs of the electrode assembly 20 to output the electrical energy of the battery cell 10. The electrical connection portion can be directly connected with the tabs, such as being directly welded with the tabs. The electrical connection portion can also be indirectly connected with the tabs, such as being indirectly connected with the tabs through a current collecting member. The current collecting member can be a metal conductor, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0112] As shown in FIGS. 3 and 4, taking the hollow structure with the casing 101 as one end forming an opening as an example, two electrical connection portions can be provided on the end cover 102, the two electrical connection portions being a positive electrical connection portion and a negative electrical connection portion respectively, the positive electrical connection portion being electrically connected with the positive tab, and the negative electrical connection portion being electrically connected with the negative tab.

[0113] Please refer to FIGS. 5 and 6, FIG. 5 is a schematic view of the electrode assembly 20 provided by some embodiments of the present application, and FIG. 6 is a schematic view of the electrode assembly 20 provided by some other embodiments of the present application. The electrode assembly 20 includes a positive electrode tab 21 and a negative electrode tab 22. The positive electrode tab 21 includes a positive electrode body and a positive tab, the positive tab being led out from one end of the positive electrode body, and most of the area of the positive tab being not coated with positive active material. Most of the area of the positive electrode body is coated with positive active material. The negative electrode tab 22 includes a negative electrode body and a negative tab, the negative tab being led out from one end of the negative electrode body, and most of the area of the negative tab being not coated with negative active material. Most of the area of the negative electrode body is coated with negative active material. The positive electrode body and the negative electrode body constitute a main body portion of the electrode assembly.

[0114] As shown in FIG. 5, the electrode assembly 20 includes a plurality of tabs arranged in a winding manner, and the electrode assembly 20 includes a flat area 23 and a bending area 24 connected with the end of the flat area 23.

[0115] The plurality of tabs arranged in a winding manner, i.e. the positive electrode tab 21 and the negative electrode tab 22, are arranged in a stacking manner and wound around a set axis to form the electrode assembly 20. The flat area 23 refers to the part of the tab extending along a plane after winding. The bending area 24 refers to the part of the tab extending along an arc surface after winding. For example, as shown in FIG. 5, the part between the front side surface and the back side surface of the electrode assembly 20 is formed as the flat area 23, and the extending direction of the tab in the flat area 23 is the length direction of the flat area 23. As shown in FIG. 5, the length dimension of the flat area 23 in the left-right direction is B1, and the left and right ends of the flat area 23 are the bending areas 24.

[0116] As shown in FIG. 6, the electrode assembly 120 includes a plurality of electrode sheets arranged in a stack, and the electrode assembly 20 has a flat area 23.

[0117] The plurality of electrode sheets arranged in a stack, such as at least one positive electrode sheet 21 and at least one negative electrode sheet 22, are arranged in a stack to form the electrode assembly 20, and the flat area 23 is formed by at least a portion of the positive electrode sheet 21 and at least a portion of the negative electrode sheet 22 arranged in a stack. The flat area 23 is formed by at least a portion of the positive electrode sheet 21 and at least a portion of the negative electrode sheet 22 arranged in a stack, and the extension direction of the electrode sheets in the flat area 23 is the length direction of the flat area 23. As shown in FIG. 6, the length of the flat area 23 in the left-right direction is B1.

[0118] Please refer to FIGS. 7-17, FIGS. 7-11 are schematic diagrams of the shell 10 according to some embodiments of the present application; FIGS. 12-16 are schematic diagrams of the pressure relief component 40 according to some embodiments of the present application; and FIG. 17 is a schematic diagram of the pressure relief component installed on the first wall portion according to some embodiments of the present application. The battery cell 100 according to the embodiments of the present application includes: an electrode assembly 20 and a shell 10, the electrode assembly 20 includes at least one positive electrode sheet 21 and at least one negative electrode sheet 22, the at least one positive electrode sheet 21 and the at least one negative electrode sheet 22 are stacked and form a flat area 23, at least a portion of the positive electrode sheet 21 and at least a portion of the negative electrode sheet 22 are arranged in a stack in the flat area 23 along a first direction F1; the shell 10 is used to accommodate the electrode assembly 20, and the shell 10 includes a first wall portion 11; the battery cell 100 further includes a pressure relief component 40, the pressure relief component 40 is arranged on the first wall portion 11, the pressure relief component 40 is provided with a first score groove 41, and the pressure relief component 40 is configured to be able to split along at least a portion of the first score groove 41 when the battery cell 100 is relieved.

[0119] The first score groove 41 includes a first groove segment 411 extending along a straight line trajectory, the length 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, 0.3mm≤W≤0.8mm.

[0120] The shell 10 refers to the outermost structural member of the battery cell 100, and the shell 10 accommodates the electrode assembly 20 and electrolyte, etc.

[0121] The electrode assembly 20 can be a stack type, i.e., a plurality of electrode sheets of the electrode assembly 20 are arranged in a stack, and the electrode sheets form a flat area 23 after stacking, in the flat area 23, at least a portion of the positive electrode sheet 21 and at least a portion of the negative electrode sheet 22 are arranged in a stack along the first direction F1, or at least a portion of the positive electrode sheet 21 and the negative electrode sheet 22 are arranged in a stack along the first direction F1, so that the swelling deformation of the electrode assembly 20 is particularly obvious in the first direction F1.

[0122] The electrode assembly 20 can also be wound, and the positive electrode tab 21 and the negative electrode tab 22 of the electrode assembly 20 are wound to form a flat area 23 after being stacked with the separator. In the flat area 23, a portion of the positive electrode tab 21 and a portion of the negative electrode tab 22 are arranged in layers in the first direction F1. For example, each layer of the positive electrode tab 21 and each layer of the negative electrode tab 22 after being wound can be penetrated by an axis extending in the first direction F1. Thus, the swelling deformation of the electrode assembly 20 is particularly obvious in the first direction F1.

[0123] The housing 10 includes a first wall portion 11 and two second wall portions 12, which are respectively located on both sides of the electrode assembly 20 in the first direction F1. The swelling of the electrode assembly 20 mostly acts 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, which is perpendicular to the first direction F1. The thickness direction of the first wall portion 11 is the second direction F2. The first wall portion 11 is provided with a pressure relief component 40.

[0124] The pressure relief component 40 is a component for relieving the internal pressure of the battery monomer 100. When the internal pressure of the battery monomer 100 reaches a threshold value, the pressure relief component 40 can discharge the discharge medium in the battery monomer 100 to achieve the purpose of pressure relief. The threshold value is designed differently according to different design requirements. The threshold value can depend on the material of one or more of the positive electrode tab 21, the negative electrode tab 22, the electrolyte, and the separator in the battery monomer 100.

[0125] When the battery monomer 100 is relieved, it can be broken along at least a portion of the first score groove 41, i.e., the first score groove 41 of the pressure relief component 40 is a weak part. The first score groove 41 includes a first groove segment 411 extending along a straight trajectory. The length direction of the first groove segment 411 is perpendicular to the first direction F1. As shown in FIGS. 8 and 12, the first groove segment 411 extends in the third direction F3. The dimension W of the groove bottom surface of the first groove segment 411 in the first direction F1 is the width dimension of the groove bottom surface of the first groove segment 411.

[0126] The first groove segment 411 is the thinnest area of the pressure relief component 40, along the thickness direction (second direction F2) of the first wall portion 11, the first groove segment 411 has the smallest residual thickness, and the extension direction of the first groove segment 411 is perpendicular to the first direction F1. When the battery monomer 100 deforms due to the expansion of the electrode assembly 20 during charging and discharging, the deformation of the first wall portion 11 is mainly borne by the first groove segment 411. Since the groove segment with a smaller width size deforms more than the groove segment with a larger width size under the same expansion force, the smaller the size of the groove bottom surface of the first groove segment 411 in the first direction F1, the weaker the ability of the first groove segment 411 to bear the deformation in the first direction F1. During long-term charging and discharging of the battery monomer 100, the strain and strain amplitude generated at the first groove segment 411 are greater, and the pressure relief component 40 is more prone to low-cycle fatigue cracking failure, and the long-term reliability is lower.

[0127] In addition, during the manufacturing process of the score groove, the material at the score position is extruded to the surrounding. During the manufacturing process of the first groove segment 411, the more material is extruded to the surrounding at the position of the first groove segment 411 when the groove bottom surface width of the first groove segment 411 is greater. At this time, the requirements (such as tonnage and precision) of the manufacturing equipment (such as a punching machine tool) are higher, and the pressure relief component 40 is more prone to uneven material flow, resulting in unqualified appearance size or other internal micro-defects, thereby reducing the manufacturing yield of the pressure relief component 40.

[0128] Therefore, as shown in FIGS. 9-14, the size W of the groove bottom surface of the first groove segment 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, 0.8 mm, or a range value between any two of them. In this way, the size of the weak area is increased to some extent, the ability of the first groove segment 411 to bear the deformation in the first direction F1 is increased, and the deformation amount of the pressure relief component 40 at the first groove segment 411 is reduced. Thus, during long-term charging and discharging of the battery monomer 100, low-cycle fatigue abnormal opening of the pressure relief component 40 caused by the over-narrowing of the thinnest area can be avoided to some extent, the probability of the pressure relief component 40 being pulled and damaged to cause leakage is reduced, the reliability of the battery monomer 100 is improved, the material flow is uniform during the manufacturing process, the appearance qualification rate is improved, the manufacturing defects are reduced, and the manufacturing yield of the product is improved.

[0129] In the technical solutions of the embodiments of the present application, by limiting the size of the groove bottom surface of the first groove section 411, the damage cracking and liquid leakage of the thinnest area of the first groove section 411 due to the expansion and deformation of the electrode assembly 20 can be reduced, the probability of low cycle fatigue can be reduced to a certain extent, and the reliability of the battery monomer 100 can be improved; meanwhile, the flow of the material in the manufacturing process is uniform, the appearance qualification rate is improved, the defects generated in the manufacturing process are reduced, and the manufacturing rate of the product is improved.

[0130] 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 in combination with the embodiments and the drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor belong to the scope of protection of the present application.

[0131] Embodiment 1

[0132] 1) Preparation of positive electrode sheet

[0133] LiNi0.7Co0.1Mn0.1O2, a conductive agent Super P, and a binder polyvinylidene fluoride (PVDF) are prepared into a positive electrode slurry in N-methyl pyrrolidone (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 component is 8:1:1. The positive electrode slurry is coated on the upper and lower surfaces of the current collector aluminum foil, dried at 85℃, then cold-pressed, and then edge cut, sheet cut, and strip cut, and dried at 85℃ under vacuum conditions for 4h to prepare a positive electrode sheet.

[0134] 2) Preparation of negative electrode sheet

[0135] Graphite, a conductive agent Super P, a thickening agent carboxymethyl cellulose (CMC), and an adhesive styrene butadiene rubber (SBR) are uniformly mixed 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 monoxide, Super P, CMC, and the adhesive styrene butadiene rubber (SBR) in the solid component 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℃, then cold-pressed, edge cut, sheet cut, and strip cut, and dried at 120℃ under vacuum conditions for 12h to prepare a negative electrode sheet.

[0136] 3) Preparation of electrolyte

[0137] In an argon atmosphere glove box (H2O < 0.1 ppm, O2 < 0.1 ppm), the fully dried electrolyte salt LiPF6 was dissolved in a mixed solvent (the mixed solvent included ethylene carbonate (EC) and diethyl carbonate (DEC), and the ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed in a mass ratio of 50:50), and after being mixed uniformly, a liquid electrolyte with a concentration of 1 mol / L was obtained.

[0138] 4) separator

[0139] A 16 μm polyethylene film was used as the separator.

[0140] 5) Preparation of lithium ion battery

[0141] The positive electrode sheet, the separator, and the negative electrode sheet were stacked in order, with the separator between the positive and negative electrode sheets to separate the positive and negative electrodes, and the bare cell was obtained by winding. The tab was welded, the bare cell was placed in an aluminum shell, the electrolyte prepared above was injected into the dried shell, and the lithium ion battery was prepared after packaging, standing, formation, shaping, capacity testing, and the like.

[0142] The battery cell preparation methods in Examples 2-4 and Comparative Examples 1-2 were the same as in Example 1, wherein the pressure relief component was integrally punched on the shell, the shell was a cuboid structure, the shell body was a structure with an opening at one end, the wall part opposite to the end cover of the shell body was a first wall part, the first wall part was a rectangular wall part, the shell body was an aluminum alloy material, the wall part opposite to the end cover of the shell body was a first wall part, and the first wall part was provided with a pressure relief component.

[0143] In each of the examples and comparative examples, the first groove segment with the smallest residual thickness of the first score groove was measured, and the first groove segment extended in the first direction. When measuring the width dimension W of the groove bottom surface of the groove segment in the first direction, the first wall part was cut open along a surface perpendicular to the first direction, and W was measured on the cut surface.

[0144] The examples and comparative examples differed in that the width dimension of the first groove segment in the first direction was different, as shown in Table 1.

[0145] The cycle number of the battery cell 100 (i.e., the number of fatigue failures of the battery cell 100) when liquid leakage occurred in the pressure relief component 40 of the lithium ion battery obtained in Examples 1-4 and Comparative Examples 1-2 was characterized, and the characterization results are shown in Table 1.

[0146] The measurement method of the fatigue number of the battery cell is as follows.

[0147] 1) Prepare a special test fixture, specifically, the fixture is composed of three 10mm steel plates (first steel plate, second steel plate, third steel plate), each steel plate can completely cover the large surface of the battery monomer, 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 steel plate and the third steel plate and is constrained by a guide rail, the second steel plate can only move in the direction perpendicular to the plane of the steel plate; the battery monomer can be installed between the first steel plate and the second steel plate, and the large surface (the surface with the largest area of the outer surface of the battery monomer) of the battery monomer is attached to the first steel plate and the second steel plate, a pressure sensor is provided between the second steel plate and the third steel plate, and the initial extrusion force of the second steel plate on the battery monomer is adjusted by adjusting the position of the second steel plate.

[0148] 2) Fix a battery monomer in the special test fixture, ensure that the large surface of the battery monomer is attached to the first steel plate and the second steel plate, adjust the position of the second steel plate so that the initial extrusion force of the second steel plate on the battery monomer is 2000N, and connect the two electrical connection parts of the battery monomer to the special battery charging and discharging equipment.

[0149] 3) Place the battery monomer and the fixture in a constant temperature environment of 35±2℃, and start the test after the battery monomer reaches temperature equilibrium.

[0150] 4) The test steps refer to the 6.4 chapter "Standard Cycle Life" of "GBT31484-2015 Cycle Life Requirements and Test Methods for Power Storage Batteries for Electric Vehicles", and the test cycle cutoff condition is changed to "stop testing until the notch groove of the pressure relief component is damaged".

[0151] Specifically, test according to the following steps:

[0152] a) Discharge at 1I(A) to the company's specified discharge termination condition;

[0153] b) Rest for no less than 30 minutes or the company's specified rest condition;

[0154] c) Charge according to the method of "GBT31484-2015 Cycle Life Requirements and Test Methods for Power Storage Batteries for Electric Vehicles" 6.1.1.3;

[0155] d) Rest for no less than 30 minutes or the company's specified rest condition;

[0156] e) Discharge at 1I1(A) to the company's specified discharge termination condition,

[0157] f) Cycle according to b) to e) until the notch groove of the pressure relief component is damaged to stop the test.

[0158] That is, the test process continuously observes the pressure relief component of the battery monomer until the pressure relief component leaks, and the cycle number is recorded as the fatigue failure number of the battery monomer, wherein the test results are as shown in Table 1.

[0159] Table 1

[0160] From 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 fatigue failure number is too low to meet the life requirement, but when W is greater than 0.8 mm, the manufacturing yield will be reduced, and further adjusting the size of W within the given range is beneficial to the battery monomer 100 having better cycle performance and manufacturing yield.

[0161] As shown in FIGS. 4, 12-14, and 17, in some embodiments, the pressure relief component 40 is welded and fixed with the first wall portion 11, the pressure relief component 40 is installed on the first wall portion 11, and the size of the groove bottom surface of the first groove segment 411 in the first direction F1 is W, which satisfies: 0.4 mm≤W≤0.75 mm, and optionally, 0.44 mm≤W≤0.65 mm.

[0162] As shown in FIGS. 4, 12-14, the pressure relief component 40 and the shell 10 are two separate components, which are separately formed and then installed together. Specifically, the pressure relief component 40 can be a rupture disc, a burst disc, a safety valve, or the like. The pressure relief component 40 can be installed on the first wall portion 11 by adhesion, 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 monomer 100 reaches a threshold value, the pressure relief component 40 opens at least part of the through hole, and the discharge medium in the battery monomer 100 is discharged through the through hole to release the pressure in the battery monomer 100.

[0163] Since the pressure relief component 40 is a component independent of the shell 10, the pressure relief component 40 and the shell 10 can be separately produced and then assembled, which has low production difficulty and high efficiency.

[0164] In such a split structure, the overall rigidity of the wall portion (i.e., the first wall portion 11) of the shell 10 is relatively small. During the charging and discharging process of the battery monomer 100, the greater the deformation of the first wall portion 11 and the pressure relief component 40, the greater the width W of the first score groove 41 needs to be, and in particular, the width dimension of the first groove segment 411 in the first direction F1 needs to be increased.

[0165] Meanwhile, in the manufacturing process of the split structure, the pressure relief component 40 is separately manufactured. First, a sheet is punched to form the morphology of the score groove, and then the excess material is removed to form the pressure relief component 40. During the punching process, the flow of material is small and there is a large flow space, so that a larger groove segment width size can be achieved while meeting the product yield requirement.

[0166] Thus, the dimension W of the groove bottom surface of the first groove section 411 in the first direction F1 is limited to between 0.4 mm and 0.75 mm, and W can be any one of 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.

[0167] Thus, the probability of low-cycle fatigue phenomenon can be reduced to some extent, and the flow of material during manufacturing can be uniform, the appearance qualification rate can be improved, the manufacturing defects can be reduced, and the manufacturing rate of products can be improved.

[0168] In some further examples, 0.44 mm≤W≤0.65 mm.

[0169] W can be any one of 0.44 mm, 0.45 mm, 0.46 mm, 0.47 mm, 0.48 mm, 0.49 mm, 0.5 mm, 0.51 mm, 0.52 mm, 0.53 mm, 0.54 mm, 0.55 mm, 0.56 mm, 0.57 mm, 0.58 mm, 0.59 mm, 0.6 mm, 0.61 mm, 0.62 mm, 0.63 mm, 0.64 mm, 0.65 mm or a range value between any two of them.

[0170] Thus, the probability of low-cycle fatigue phenomenon can be reduced to some extent, and the flow of material during manufacturing can be uniform, the appearance qualification rate can be improved, the manufacturing defects can be reduced, and the manufacturing rate of products can be improved.

[0171] As shown in FIG. 17, in some embodiments, the first wall portion 11 has a width D in the first direction F1, and satisfies: 0.008≤W / D≤0.019, and 20 mm≤D≤80 mm.

[0172] 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, 80 mm or a range value between any two of them.

[0173] Wherein, on a certain size of battery monomer, if W / D is too small, the width W of the first groove section 411 is too small, the ability to withstand deformation in the first direction F1 at the first groove section 411 is weaker, the strain and strain amplitude generated at the first groove section 411 during long-term charging and discharging of the battery monomer 100 is larger, the pressure relief component 40 is more prone to low-cycle fatigue cracking failure, 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 prone to uneven flow phenomenon, resulting in unqualified appearance size or other internal micro defects, which in turn will reduce the manufacturing yield of the pressure relief component 40.

[0174] Therefore, W / D can be limited to between 0.008 and 0.019, W / D can be any one of 0.008, 0.009, 0.01, 0.011, 0.012, 0.013, 0.014, 0.015, 0.016, 0.017, 0.018, 0.019 point value or range value between any two.

[0175] Thereby, the weakest area at the first groove section 411 can be reduced due to the expansion and deformation of the electrode assembly 20, and damage cracking and liquid leakage can be avoided, the probability of low-cycle fatigue phenomenon can be reduced to some extent, the flow is uniform during manufacturing, the appearance qualification rate is improved, the manufacturing defects are reduced, and the manufacturing yield of the product is improved.

[0176] Referring to FIGS. 12 and 13, in 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 configured to guide at least part of the predetermined pressure relief area 401 to flip over to open at least part of the predetermined pressure relief area 401. The second score groove 42 is a flip score groove provided on the pressure relief component 40, and when the pressure relief component 40 is broken along at least part of the first score groove 41, the second score groove 42 can guide at least part of the predetermined pressure relief area 401 to flip over, that is, the second score groove 42 helps the predetermined pressure relief area 401 to flip over, making it easier for the predetermined pressure relief area 401 to flip over to the outside of the battery cell 100, thereby quickly opening the predetermined pressure relief area 401. The second score groove 42 can guide the entire predetermined pressure relief area 401 to flip over, or the second score groove 42 can only guide part of the predetermined pressure relief area 401 to flip over. During the pressure relief of the battery cell 100, the pressure relief component 40 can be broken along at least part of the first score groove 41, but generally not broken along the second score groove 42, and the predetermined pressure relief area 401 can flip over about the second score groove 42 after the first score groove 41 is broken, so as to facilitate the pressure relief after the inside of the housing 10 and the outside of the housing 10 are communicated with each other after the predetermined pressure relief area 401 flips over. In some embodiments, the minimum thickness of the residual part of the area where the pressure relief component 40 is provided with the first score groove 41 can be less than the minimum thickness of the residual part of the area where the pressure relief component 40 is provided with the second score groove 42, so that the area where the pressure relief component 40 is provided with the first score groove 41 is easier to break than the area where the pressure relief component 40 is provided with the second score groove 42. The second score groove 42 can be formed in various ways, such as punch forming, milling forming, etc. The shape of the second score groove 42 can be various, such as a groove extending along an arc trajectory, or a groove extending along a straight line trajectory. The cross-sectional shape of the second score groove 42 can be various, such as a rectangle, a trapezoid, etc.

[0177] By providing the second score 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, so as to reduce the risk of fire explosion, connection failure, etc. caused by untimely pressure relief of the battery cell 100, and improve the use reliability of the battery cell 100.

[0178] In some embodiments, the maximum width of the second score groove 42 is not greater than the maximum width of the first score groove 41.

[0179] Since the first score groove 41 needs to bear greater pressure and serve as the main pressure relief path during the pressure relief of the battery cell 100, the maximum width of the second score groove 42 can be appropriately reduced.

[0180] In addition, in the manufacturing process of the second score groove 42, the same method as that of the first score groove 41 can be used to form the shape, for example, a stamping process can be used, and when the score groove with a large residual thickness is manufactured, a small width size can be correspondingly formed, so that the second score groove 42 with a narrow size and a large residual thickness can be formed.

[0181] Therefore, through the above arrangement, not only is the forming of the second score groove 42 facilitated, but also the situation that the strength of the second score groove 42 is too large to cause the battery cell 100 to be difficult to release pressure in a predetermined manner is avoided to some extent, and the reliability of the battery cell 100 is improved.

[0182] In some embodiments, the residual thickness of the second score groove 42 is greater than the residual thickness of the first score groove 41.

[0183] The minimum residual thickness of the second score groove 42 is the minimum thickness of the residual part of the pressure relief component 40 after the second score groove 42 is set, which can be the groove bottom wall of the second score groove 42. The thickness of the groove bottom wall of the second score groove 42 can be uniform or non-uniform, and if the thickness of the groove bottom wall of the second score groove 42 is non-uniform, the thickness of the thinnest position of the groove bottom wall of the second score groove 42 is the minimum residual thickness of the second score groove 42.

[0184] In the present embodiment, the strength of the area where the pressure relief component 40 is provided with the first score groove 41 can be made smaller than the strength of the area where the pressure relief component 40 is provided with the second score groove 42, so that the pressure relief component 40 can preferentially crack along the first score groove 41 to achieve rapid opening of the predetermined pressure relief area 401.

[0185] Please refer to FIG. 12, in some embodiments, the first score groove 41 further comprises two second groove segments 412, the two second groove segments 412 are oppositely arranged, the first groove segment 411 is respectively connected to one end of the two second groove segments 412, and the other end of the two second groove segments 412 is connected to the two ends of the second score groove 42, and the first groove segment 411, the two second groove segments 412 and the second score groove 42 jointly define the predetermined pressure relief area 401.

[0186] For example, in the embodiment shown in FIG. 12, the first groove segment 411 and the second score groove 42 are oppositely arranged and parallel to each other, the two ends of the first groove segment 411 are respectively connected to the two second groove segments 412, the two ends of the second score groove 42 are respectively connected to the two second groove segments 412, and the two second groove segments 412, the first groove segment 411 and the second score groove 42 form a closed ring structure; in the second direction F2, the outer edge of the orthographic projection of the ring 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 score groove 41 and the second score groove 42 in the second direction F2.

[0187] The first groove segment 411 and the second score groove 42 extend along a straight trajectory, as shown in FIG. 12, and 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.

[0188] The second groove segment 412 can extend along a straight trajectory, for example, along the first direction F1, so as to form a square-shaped predetermined pressure relief area 401; or the second groove segment 412 can extend along an arc trajectory, so as to form a runway-shaped predetermined pressure relief area 401.

[0189] In the present embodiment, the first groove segment 411, the second score groove 42, and the two second groove segments 412 are connected to form a ring-shaped structure, so that the intersection position of the first groove segment 411 and the second groove segment 412 is more weak and is more prone to cracking and opening 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 and increasing the pressure relief area of the battery monomer 100 and improving the pressure relief rate of the battery monomer 100.

[0190] In some embodiments, the second score groove 42 is arranged in parallel and opposite to the first groove segment 411, and the second groove segment extends along a straight and / or arc trajectory.

[0191] In some examples, the length dimension of the second score groove 42 is the same as the length dimension of the first groove segment 411, the second groove segment 412 is a straight line-shaped groove, the second groove segment 412 is perpendicular to the first groove segment 411, and the second groove segment 412 extends along a straight trajectory, which can reduce the forming difficulty of the second groove segment 412.

[0192] In some examples, the length dimension of the second score groove 42 is the same as the length dimension of the first groove segment 411, the second groove segment 412 extends along an arc trajectory, and the second groove segment 412 is an arc line-shaped groove. Thus, the pressure relief component 40 is more prone to cracking along the second groove segment 412 when the battery monomer 100 is relieved, so as to achieve more rapid opening of the predetermined pressure relief area 401.

[0193] In some examples, the length dimension of the second score groove 42 is smaller than the length dimension of the first groove segment 411, each second groove segment includes two parts, one part extends along an arc, and the other part extends along a straight line, thereby forming a ring-shaped structure, and to a certain extent, the length of the second score groove 42 is shortened, the length of the first score groove 41 is increased, which is conducive to more rapid opening of the predetermined pressure relief area 401.

[0194] As shown in FIGS. 12-14, in some embodiments, along the thickness direction of the first wall portion 11, the pressure relief component 40 has oppositely arranged first and second surfaces 40a and 40b, and the first and second score grooves 41 and 42 are both arranged on the first surface 40a.

[0195] The thickness direction of the first wall portion 11 is the second direction F2 as shown in FIG. 13, one of the first and second surfaces 40a and 40b can be an outer surface of the pressure relief component 40, and the other can be an inner surface of the pressure relief component 40, the outer surface of the pressure relief component 40 faces the outside of the battery monomer 100, and the inner surface of the pressure relief component 40 faces the inside of the battery monomer 100. The first and second surfaces 40a and 40b can be flat surfaces, and the first and second surfaces 40a and 40b can be arranged in parallel or at a non-zero angle. The first and second score grooves 41 and 42 are arranged on the first surface 40a, that is, the two score grooves are recessed from the first surface to the direction close to the second surface, and the groove opening of the score groove is formed on the first surface 40a.

[0196] In the present embodiment, the first and second score grooves 41 and 42 are both arranged on the first surface 40a, which is beneficial to the processing and forming of the first and second score grooves 41 and 42, and improves the processing efficiency.

[0197] As shown in FIGS. 9 and 10, in some embodiments, the first surface 40a is a surface of the pressure relief component 40 facing the outside of the shell 10.

[0198] It can be understood that the first surface 40a is an outer surface of the pressure relief component 40, and when the pressure relief component 40 is installed on the first wall portion 11, the first surface 40a is an outer surface of the first wall portion 11.

[0199] The first surface 40a is a surface of the pressure relief component 40 facing the outside of the shell, so that the first and second score grooves 41 and 42 are arranged on the outer side of the pressure relief component 40, which facilitates the processing and forming of the first and second score grooves 41 and 42 on the outside of the battery monomer 100, and is beneficial to reducing the forming difficulty of the first and second score grooves 41 and 42, thereby improving the production efficiency of the battery monomer 100.

[0200] As shown in FIGS. 7-11, 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, which satisfies: 0.3mm≤W≤0.5mm, and optionally, 0.35mm≤W≤0.45mm.

[0201] As shown in FIGS. 7-11, the pressure relief component 40 is integrally formed with the first wall portion 11, and the first score groove 41 can be directly provided on the first wall portion 11 to form an integrated structure. The first wall portion 11 forms a weak area at the region where the first score groove 41 is provided. The pressure relief component 40 is formed in a simple manner, and the connection process of the pressure relief component 40 and the first wall portion 11 is omitted, thereby reducing the production cost of the battery cell 100.

[0202] In the integrated structure, the overall rigidity of the wall portion (i.e., the first wall portion 11) of the housing 10 is large, and the deformation of the first wall portion 11 is small during the long-term charging and discharging of the battery cell 100. Therefore, the width of the first groove segment 411 can be relatively small, and in particular, the width of the first groove segment 411 in the first direction F1 can be relatively small.

[0203] However, the score groove is usually manufactured by a stamping process. During the manufacturing of the score groove, more material is extruded to the surrounding at the score position. In particular, in the integrated structure, the stamping area is a closed area, and the flow of material is large and the space for the flow of material is small during the stamping process. Therefore, when the width of the groove bottom of the first groove segment 411 is larger, more material is extruded to the surrounding at the position of the first groove segment 411. In this case, the requirements (e.g., tonnage and precision) of the manufacturing equipment (e.g., a stamping machine) are higher, and the flow of material is not uniform, which leads to unqualified appearance size or other internal defects, thereby reducing the manufacturing yield of the pressure relief component 40.

[0204] Therefore, the width W of the groove bottom of the first groove segment 411 in the first direction F1 is limited to 0.3-0.5 mm. W can be any one of 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm or a range value between any two of them.

[0205] In this way, the damage, cracking, and leakage at the thinnest area of the first groove segment 411 due to the expansion and deformation of the electrode assembly 20 can be reduced, the probability of low-cycle fatigue can be reduced to some extent, the flow of material during the manufacturing process is uniform, the qualified rate of appearance is improved, the defects generated during the manufacturing are reduced, and the manufacturing yield of the product is improved.

[0206] In some further examples, 0.35 mm≤W≤0.45 mm.

[0207] W can be any one of 0.35 mm, 0.36 mm, 0.37 mm, 0.38 mm, 0.39 mm, 0.4 mm, 0.41 mm, 0.42 mm, 0.43 mm, 0.44 mm, 0.45 mm or a range value between any two of them.

[0208] Therefore, the thinnest area of the first groove segment 411 can be further reduced in deformation due to the expansion of the electrode assembly 20, and the probability of low cycle fatigue can be reduced to some extent. Meanwhile, the flow of material can be uniform during manufacturing, the appearance qualification rate can be improved, the manufacturing defects can be reduced, and the manufacturing yield of the product can be improved.

[0209] Referring to FIGS. 7-16, in some embodiments, the first score groove 41 includes a first groove segment 411 and a second groove segment 412, the first groove segment 411 is connected to the second groove segment 412, and the first groove segment 411 and the second groove segment 412 together define the predetermined pressure relief area 401.

[0210] The first groove segment 411 and the second groove segment 412 are two groove segments in the first score groove 41. The second groove segment 412 can be a straight line groove extending along a straight line trajectory or a non-straight line groove extending along a non-straight line trajectory, such as an arc-shaped groove extending along an arc trajectory. If the first groove segment 411 and the second groove segment 412 both extend along a straight line trajectory, 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 at the ends to form a V-shaped, L-shaped, or other structure, or the first groove segment 411 and the second groove segment 412 can be arranged in a cross shape. 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-shaped, N-shaped, or H-shaped structure.

[0211] In the present embodiment, the predetermined pressure relief area 401 is defined by the first groove segment 411 and the second groove segment 412. The first score groove 41 with such a structure is simple in structure, and the stress is more concentrated at the connection position of the first groove segment 411 and the second groove segment 412, which is more vulnerable. Therefore, when the pressure relief component 40 is cracked at the connection position of the first groove segment 411 and the second groove segment 412 during thermal runaway of the battery monomer 100, the first groove segment 411 and the second groove segment 412 can be quickly cracked, the predetermined pressure relief area 401 can be quickly opened, and timely pressure relief can be achieved.

[0212] Referring to FIG. 15, in some embodiments, the first score groove 41 includes two first groove segments 411 and one second groove segment 412, the two first groove segments 411 are arranged opposite to each other, the two first groove segments 411 are respectively connected to the second groove segment 412, the connection position of the second groove segment 412 and each first groove segment 411 is offset from the two ends of the first groove segment 411, and the two first groove segments 411 and the second groove segment 412 together define the predetermined pressure relief area 401.

[0213] ​As an example, in the embodiment shown in FIG. 15, the two first groove segments 411 and the second groove segment 412 form a H-shaped structure, and the ends of the second groove segment 412 are connected to the middle portions of the corresponding first groove segments 411 respectively, and the ends of the two first groove segments 411 on the same side of the second groove segment 412 define a first straight segment 413, and the outer edges of the first straight segment 413 and the orthographic projection of the first groove segments 411 in the second direction F2 constitute the predetermined opening boundary of the predetermined pressure relief area 401, i.e., the predetermined opening boundary is jointly formed by the lines connecting the ends of the first score groove 41 and the outer edges of the orthographic projection of a portion of the first score groove 41 in the second direction. It should be noted that the connection positions of the second groove segment 412 and the first groove segments 411 can be located at the midpoint positions of the first groove segments 411, or can deviate from the midpoint positions of the first groove segments 411.

[0214] In the embodiment, each first groove segment 411 extends along the third direction F3, and the second groove segment 412 can extend along a straight line trajectory, for example, the second groove segment 412 extends along the first direction F1, and 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 dimension of the groove bottom surface of the first groove segment 411 is W, and 0.15 mm≤W≤0.8 mm.

[0215] In the embodiment, the two first groove segments 411 connect the second groove segment 412, so that the intersection position of the first groove segment 411 and the second groove segment 412 is more weak and more easily cracked and opened to open the predetermined pressure relief area 401 for pressure relief; the two first groove segments 411 are oppositely arranged, which can further increase the opening area of the predetermined pressure relief area 401, thereby increasing the pressure relief area of the battery monomer 100 and improving the pressure relief rate of the battery monomer 100.

[0216] Please refer to FIG. 8, in some embodiments, the first score groove 41 includes one first groove segment 411 and two second groove segments 412, the two second groove segments 412 are oppositely arranged, the first groove segment 411 connects the two second groove segments 412, and the connection position of each second groove segment 412 and the first groove segment 411 deviates from the two ends of the corresponding second groove segment 412, and the first groove segment 411 and the two second groove segments 412 jointly define the predetermined pressure relief area 401.

[0217] As an example, in the embodiment shown in Figure 8, the first groove segment 411 and the two second groove segments 412 form an H-shaped structure. The ends of the first groove segment 411 are connected to the middle of the corresponding second groove segment 412. A second straight segment 414 is defined between the ends of the two second groove segments 412 located on the same side of the first groove segment 411. The outer edges of the orthographic projections of the second straight segment 414 and the second groove segment 412 in the second direction F2 constitute the predetermined opening boundary of the predetermined pressure relief zone 401. That is, the predetermined opening boundary is jointly enclosed by the line connecting the multiple ends of the first groove 41 and the outer edge of the orthographic projection of a portion of the first groove 41 in the second direction. It should be noted that the connection position between the second groove segment 412 and the first groove segment 411 can be located at the midpoint of the second groove segment 412 or it can be off-center from the midpoint of the second groove segment 412.

[0218] The first groove segment 411 extends along the third direction F3, and the second groove segment 412 can extend along a straight trajectory. For example, each second groove segment 412 extends along the first direction F1. In the first direction F1, the dimension of the bottom surface of the second groove segment 412 is greater than 0.15mm, and the width dimension of the bottom surface of the first groove segment 411 is W, where 0.15mm≤W≤0.8mm.

[0219] In this embodiment, the first groove segment 411 connects two second groove segments 412, making the intersection of the first groove segment 411 and the second groove segment 412 weaker, making it easier to crack and open the predetermined pressure relief area 401 for pressure relief; the two second groove segments 412 are arranged opposite 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.

[0220] Referring to Figure 16, in some embodiments, the first groove 41 includes a first groove segment 411 and four second groove segments 412. The two ends of the first groove segment 411 are respectively connected to two second groove segments 412 arranged at a preset angle. The first groove segment 411 and the four second groove segments 412 together define a predetermined pressure relief area 401.

[0221] As an example, in the embodiment shown in FIG16, the two ends of the first groove segment 411 are respectively connected to two second groove segments 412 arranged at a preset angle; in the second direction F2, an arc segment 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 segments 412 located at the same end of the first groove segment 411, and a third straight segment 416 is defined between the free ends of the orthographic projections of the two second groove segments 412 located on the same side of the first groove segment 411. The two arc segments 415 and the two third straight segments 416 together constitute the predetermined opening boundary of the predetermined pressure relief area 401, that is, the predetermined opening boundary is enclosed by the line connecting the multiple ends of the first groove 41.

[0222] In some embodiments, the first groove segment 411 extends along a straight line trajectory, and the second groove segment 412 extends along an arc line trajectory.

[0223] In some embodiments, the first groove segment 411 extends along a straight line trajectory, and the second groove segment 412 extends along an arc line trajectory.

[0224] In some embodiments, the first groove segment 411 extends along a straight line trajectory, and the second groove segment 412 extends along an arc line trajectory.

[0225] In some embodiments, the first groove segment 411 extends along a straight line trajectory, and the second groove segment 412 extends along an arc line trajectory.

[0226] In some embodiments, the first groove segment 411 extends along a straight line trajectory, and the second groove segment 412 extends along an arc line trajectory.

[0227] In some embodiments, the first groove segment 411 extends along a straight line trajectory, and the second groove segment 412 extends along an arc line trajectory.

[0228] In some embodiments, the first groove segment 411 extends along a straight line trajectory, and the second groove segment 412 extends along an arc line trajectory.

[0229] In some embodiments, the first groove segment 411 extends along a straight line trajectory, and the second groove segment 412 extends along an arc line trajectory.

[0230] The second score groove 42 is a flip score groove provided on the pressure relief member 40. When the pressure relief member 40 is split along at least a portion of the first score groove 41, the second score groove 42 can guide at least a portion of the predetermined pressure relief area 401 to flip. That is, the second score groove 42 can help the predetermined pressure relief area 401 to flip, making it easier for the predetermined pressure relief area 401 to flip outwards of the battery cell 100, and thus quickly open the predetermined pressure relief area 401. The second score groove 42 can guide the entire predetermined pressure relief area 401 to flip, or it can only guide a portion of the predetermined pressure relief area 401 to flip. During the pressure relief process of the battery cell 100, the pressure relief member 40 can be split along at least a portion of the first score groove 41, but generally not along the second score groove 42. The minimum thickness of the residual portion of the region of the pressure relief member 40 provided with the first score groove 41 can be less than the minimum thickness of the residual portion of the region of the pressure relief member 40 provided with the second score groove 42, so that the region of the pressure relief member 40 provided with the first score groove 41 is more likely to split than the region of the pressure relief member 40 provided with the second score groove 42. The second score groove 42 can be formed in various ways, such as by stamping, milling, or the like. The shape of the second score groove 42 can be various, such as a groove extending along an arcuate trajectory, or a groove extending along a straight trajectory. The shape of the cross section of the second score groove 42 can be various, such as a rectangle, a trapezoid, or the like.

[0231] The second score groove 42 and the first score groove 41 can be directly connected, or they can not be in contact with each other. The second score groove 42 and the first score groove 41 can be provided on the same surface of the pressure relief member 40 in the thickness direction of the first wall portion, or they can be provided on opposite surfaces of the pressure relief member 40 in the thickness direction of the first wall portion. If the second score groove 42 and the first score groove 41 are directly connected, they can be provided on the same surface of the pressure relief member 40. If the second score groove 42 and the first score groove 41 are not in contact with each other, the projection of the second score groove 42 and the projection of the first score groove 41 can partially overlap or not overlap in the thickness direction of the first wall portion.

[0232] The predetermined pressure relief area 401 is an area of the pressure relief member 40 defined by the first score groove 41. There can be one or more predetermined pressure relief areas 401 defined by the first score groove 41. The predetermined pressure relief area 401 can be opened when the pressure relief member 40 is split along the first score groove 41. The predetermined pressure relief area 401 and the second score groove 42 can correspond one-to-one, that is, each predetermined pressure relief area 401 can be provided in correspondence with one second score groove 42. Alternatively, each predetermined pressure relief area 401 can be provided in correspondence with multiple second score grooves 42.

[0233] As shown in FIG. 10, 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.

[0234] The minimum residual thickness of the second score groove 42 is the minimum thickness of the residual part of the pressure relief component 40 after the second score groove 42 is set, which can be the groove bottom wall of the second score groove 42. The thickness of the groove bottom wall of the second score groove 42 can be uniform or non-uniform. If the thickness of the groove bottom wall of the second score groove 42 is non-uniform, the thickness of the thinnest position of the groove bottom wall of the second score groove 42 is the minimum residual thickness of the second score groove 42.

[0235] In the present embodiment, the strength of the area of the pressure relief component 40 where the first score groove 41 is set can be made less than the strength of the area of the pressure relief component 40 where the second score groove 42 is set, so that the pressure relief component 40 can preferentially crack along the first score groove 41 to achieve rapid opening of the predetermined pressure relief area 401.

[0236] As shown in FIG. 15, in some embodiments, the projection of the second score groove 42 along the thickness direction of the first wall portion 11 does not overlap the projection of the first score groove 41.

[0237] The thickness direction of the first wall portion 11 is the second direction F2 as shown in FIG. 15. Along the thickness direction of the first wall portion 11, the projection of the extension line of the second score groove 42 can be connected to the projection of the first score groove 41, or the projection of the extension line of the first score groove 41 can be connected to the projection of the second score groove 42, or the projection of the extension line of the first score groove 41 can be connected to the projection of the extension line of the second score groove 42. The second score groove 42 and the first score groove 41 can 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 are both disposed on the first surface 40a or the second surface 40b of the pressure relief component 40; or the second score groove 42 and the first score groove 41 can 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 is disposed on one of the first surface 40a and the second surface 40b of the pressure relief component 40, and the second score groove 42 is disposed on the other.

[0238] In the present embodiment, the projection of the second score groove 42 along the thickness direction of the first wall portion 11 does not overlap the projection of the first score groove 41 along the thickness direction of the first wall portion 11, which can reduce the mutual influence of the first score groove 41 and the second score groove 42 during processing, and reduce the risk of the first score groove 41 and the second score groove 42 being connected to each other during processing.

[0239] As shown in FIG. 10, in some embodiments, the pressure relief component 40 has a first surface 40a and a second surface 40b oppositely arranged along the thickness direction of the first wall portion 11, the first score groove 41 is arranged on the first surface 40a, and the second score groove 42 is arranged on the second surface 40b.

[0240] The thickness direction of the first wall portion 11 is the second direction F2 as shown in FIG. 10, one of the first surface 40a and the second surface 40b can be an outer surface of the pressure relief component 40, and the other can be an inner surface of the pressure relief component 40, the outer surface of the pressure relief component 40 faces the outside of the battery cell 100, and the inner surface of the pressure relief component 40 faces the inside of the battery cell 100. The first surface 40a and the second surface 40b can be flat surfaces, and the first surface 40a and the second surface 40b can be arranged in parallel or at a non-zero angle. The first score groove 41 is arranged on the first surface 40a, that is, the first score groove 41 is recessed from the first surface 40a towards the second surface 40b, and the groove opening of the first score groove 41 is formed on the first surface 40a; the second score groove 42 is arranged on the second surface 40b, and the second score groove 42 is recessed from the second surface 40b towards the first surface 40a, and the groove opening of the second score groove 42 is formed on the second surface 40b. It can be understood that the groove segment arranged on the first surface 40a means that the groove segment is recessed from the first surface 40a towards the second surface 40b.

[0241] In the present embodiment, the first score groove 41 and the second score groove 42 are arranged on the first surface 40a and the second surface 40b respectively, so that the first score groove 41 and the second score groove 42 are respectively located on both sides of the pressure relief component 40 in the thickness direction, so as to facilitate the machining of the first score groove 41 and the second score groove 42 on both sides of the pressure relief component 40 respectively, and facilitate the reduction of the mutual influence of the first score groove 41 and the second score groove 42 during machining.

[0242] As shown in FIGS. 9 and 10, in some embodiments, the first surface 40a is a surface of the pressure relief component 40 facing the outside of the shell 10, and the second surface 40b is a surface of the pressure relief component 40 facing the inside of the shell 10.

[0243] It can be understood that the first surface 40a is an outer surface of the pressure relief component 40, and the second surface 40b is an inner surface of the pressure relief component 40. When the pressure relief component 40 is installed or integrally formed on the first wall portion 11, the first surface 40a is an outer surface of the first wall portion 11, and the second surface 40b is an inner surface of the first wall portion 11.

[0244] The first surface 40a is a surface of the pressure relief component 40 facing the outside of the shell, so that the first score groove 41 is arranged on the outer side of the pressure relief component 40, facilitating the forming of the first score groove 41 outside the battery monomer 100, and being conducive to reducing the forming difficulty of the first score groove 41, so as to improve the production efficiency of the battery monomer 100. The second surface 40b is a surface of the pressure relief component 40 facing the inside of the shell, so that the second score groove 42 is arranged on the inner side of the pressure relief component 40. On the one hand, during the outward turning opening process of the predetermined pressure relief area 401, the second score groove 42 is not easy to abut on the two opposite sides in the width direction, which is conducive to increasing the opening area of the predetermined pressure relief area 401. On the other hand, the second score groove 42 is not exposed to the outside of the battery monomer 100, reducing the risk of oxidation and corrosion of the pressure relief component 40 in the area of the second score groove 42.

[0245] Please refer to FIGS. 10-11, and FIG. 11 is a partial enlarged view of the circle C in FIG. 10. In some embodiments, along the thickness direction of the first wall portion 11, the pressure relief component 40 has oppositely arranged first surface 40a and second surface 40b, and the first groove segment 411 includes a plurality of levels of grooves arranged in sequence from the first surface 40a to the direction close to the second surface 40b. In two adjacent levels of grooves, the level of groove far from the first surface 40a is arranged on the groove bottom surface of the level of groove close to the first surface 40a. Among them, the level of groove farthest from the first surface 40a in the plurality of levels of grooves is the first level of groove 4111, the minimum residual thickness of the first level of groove 4111 is the minimum residual thickness of the first groove segment 411, and the groove bottom surface of the first level of groove 4111 is the groove bottom surface of the first groove segment 411.

[0246] The thickness direction of the first wall portion 11 is the second direction F2, and the groove segment can be two levels of grooves, three levels of grooves, four levels of grooves, five levels of grooves, etc. It can be understood that the groove segment is a stepped groove. Along the direction from the first surface 40a to the second surface 40b, the groove width of each level of groove gradually decreases. As shown in FIG. 11, taking the three levels of grooves as an example, the two levels of grooves are the first level of groove 4111, the second level of groove, and the third level of groove. During processing, the third level of groove with a larger width can be processed on the first surface 40a first, then the second level of groove with a slightly smaller width can be processed on the groove bottom surface of the third level of groove, and then the first level of groove 4111 with a smaller width can be processed on the groove bottom surface of the second level of groove.

[0247] The first level of groove 4111 is the level of groove farthest from the first surface 40a in the groove segment. The groove bottom surface of the first level of groove 4111 is the groove bottom surface of the groove segment, the minimum residual thickness of the first level of groove 4111 is the minimum residual thickness of the groove segment, and the maximum distance between the groove bottom surface of the first level of groove 4111 and the first surface 40a is equal to the maximum groove depth of the groove segment.

[0248] In the present embodiment, by arranging the groove segments in multiple levels along the thickness direction of the first wall portion 11, each level of groove can be machined one by one in the direction from the first surface 40a to the second surface 40b when the groove segments are formed, the forming depth of each level of groove is reduced, the forming force on the pressure relief component 40 when the first score groove 41 is formed is reduced, and the risk of damage to the pressure relief component 40 when the first score groove 41 is formed is reduced.

[0249] In some embodiments, the first score groove 41 is formed on the pressure relief component 40 by stamping.

[0250] It can be understood that the first score groove 41 is formed on the pressure relief component 40 by stamping. If the first score groove 41 is a one-level groove structure, the groove segments can be stamped on the pressure relief component 40 at one time. If the first score groove 41 is a multi-level groove structure, the groove segments can be stamped on the pressure relief component 40 multiple times, each time a level of groove is stamped, and finally the groove segments are formed after multiple stamping. It can be understood that in the embodiment in which the pressure relief component 40 is integrally formed with the first wall portion 11, the groove segments are stamped on the first wall portion 11.

[0251] In the present embodiment, the first score groove 41 is formed on the pressure relief component 40 by stamping, the forming method of the first score groove 41 is simple, and the production cost of the battery monomer 100 is reduced.

[0252] As shown in FIGS. 3 and 4, in some examples, the outer shell 10 includes a shell body 101 and an end cover 102, at least one side of the shell body 101 has an opening, the end cover 102 is connected to the shell body 101 and is used to close the opening, and the first wall portion 11 is formed on the shell body 101.

[0253] The shell body 101 can be a hollow structure with an opening at one end, or a hollow structure with openings at opposite ends. The shell body 101 can have various shapes, such as a prism, etc.

[0254] The end cover 102 is a component that closes the opening of the shell body 101 to isolate the internal environment of the battery monomer 100 from the external environment. The end cover 102 cooperates with the shell body 101 to define a receiving space for accommodating the electrode assembly 20, the electrolyte, and other components. The shape of the end cover 102 can be adapted to the shape of the outer shell 10, for example, the shell body 101 is a rectangular structure, the end cover 102 is a rectangular plate structure adapted to the outer shell 10, for another example, the shell body 101 is a cylindrical structure, and the end cover 102 is a circular plate structure adapted to the shell body 101. The material of the end cover 102 can also be various, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc. The material of the end cover 102 and the shell body 101 can be the same or different.

[0255] In the embodiment in which the shell 101 has an opening formed at one end, one end cover 102 can be correspondingly arranged. In the embodiment in which the shell 101 has openings formed at opposite ends, two end covers 102 can be correspondingly arranged, and the two end covers 102 respectively close the two openings of the shell 101, and the two end covers 102 and the shell 101 together define the accommodation space.

[0256] 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 arranged separately 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 the distance between the pressure relief component 40 and the main body portion of the electrode assembly 20 can be shortened. Thus, the path of the discharge medium flowing to the pressure relief component 40 during pressure relief can be shortened, and the time for the discharge medium to reach the pressure relief component 40 can be shortened. The timeliness of pressure relief of the battery monomer 100 is improved, and thus the reliability of the battery monomer 100 is effectively improved.

[0257] In some embodiments, the shell 101 has openings at opposite sides, and two end covers 102 are arranged to close the openings at the corresponding sides.

[0258] In the embodiment in which the shell 101 has openings formed at opposite ends, two end covers 102 can be correspondingly arranged, and the two end covers 102 respectively close the two openings of the shell 101, and the two end covers 102 and the shell 101 together define the accommodation space. The first wall portion 11 is arranged on the shell 101, and the pressure relief component 40 is arranged between the two openings. Each end cover 102 can be provided with an electrical connection portion 30. By arranging two openings on the shell 101, the manufacturing of the shell 101 can be facilitated, and the electrode assembly 20 can be led out from the two ends, and thus the two electrical connection portions 30 can be arranged separately, and the risk of short circuit of the battery monomer 100 is reduced.

[0259] The end cover 102 is provided with an electrical connection portion 30, and the electrical connection portion 30 is electrically connected with the positive electrode tab 21 or the electrical connection portion 30 is electrically connected with the negative electrode tab 22. Thus, the electrical energy of the battery monomer 100 can be input or output.

[0260] As shown in FIGS. 3 and 7, the first wall portion 11 is used to support the electrode assembly 20, and the first wall portion 11 is arranged below the electrode assembly 20.

[0261] Thus, the pressure relief component 40 can be arranged at the bottom of the battery monomer 100. The bottom of the battery monomer 100 can be provided with an exhaust passage, and the exhaust passage is in communication with the pressure relief component 40. When the battery monomer 100 is in thermal runaway, the high-temperature and high-pressure flue gas can be discharged to the exhaust passage through the pressure relief component 40 at the bottom, and then discharged to the outside.

[0262] According to the battery 1000 of the second aspect of the present application, the battery 1000 comprises the battery cell 100 according to the first aspect of the present application.

[0263] According to the power consuming device of the third aspect of the present application, the battery 1000 is used to provide power for the power consuming device. Thus, by using the battery 1000, the safety and reliability of the power consuming device can be improved.

[0264] Optionally, as shown in FIG. 1, when the battery 1000 is used in a vehicle, the battery 1000 can be arranged at the bottom, the head or the tail of the vehicle. The battery 1000 can be used to supply power for the vehicle, for example, the battery 1000 can be used as the operating power source of the vehicle. The vehicle can further comprise a controller and a motor, and the controller is used to control the battery 1000 to supply power for the motor, for example, to meet the power demand of the vehicle during starting, navigation and driving.

[0265] The battery 1000 and the vehicle comprising the same according to one embodiment of the present application will be described below in combination with the drawings.

[0266] As shown in FIG. 1, the battery 1000 is arranged at the bottom of the vehicle, and as shown in FIG. 2, the battery 1000 comprises a plurality of battery cells 100, and as shown in FIG. 3, each battery cell 100 comprises a shell 10 and an electrode assembly 20, the shell 10 is provided with an electrical connection part 30 and a pressure relief part 40, the electrical connection part 30 and the pressure relief part 40 are located at different sides of the shell 10; and the electrode assembly 20 is arranged in the shell 10.

[0267] As shown in FIG. 3, the shell 10 is generally in the shape of a quadrangular prism, and has a simple structure and is easy to form. The shell 10 has a first wall part 11, the first wall part 11 is located at one side of the electrode assembly 20 in the second direction F2, the first wall part 11 extends along the third direction F3, the first wall part 11 is provided with a through hole, the pressure relief part 40 can be installed at the through hole of the first wall part 11 by means of adhesion, welding or the like, the pressure relief part 40 is a part independent of the shell 10, the pressure relief part 40 and the shell 10 can be produced separately and then assembled, and the pressure relief part 40 can be further provided with a patch 60 on the outer side, the patch 60 cooperates with the shell 10 to protect the pressure relief part 40.

[0268] As shown in FIGS. 12-14, the pressure relief part 40 is provided with a first score groove 41 and a second score groove 42, the residual thickness at the first score groove 41 is less than the residual thickness at the second score groove 42.

[0269] The pressure relief component 40 is configured to be broken along at least part of the first score groove 41 when the battery cell 100 is relieved of pressure. Specifically, the first score groove 41 includes one first groove segment 411 and two second groove segments 412, the first groove segment 411 and the second score groove 42 are oppositely arranged and respectively extend along the third direction F3, the two second groove segments 412 are oppositely arranged and form an arc-shaped groove, two ends of each first groove segment 411 are respectively connected with the two second groove segments 412, and the two second groove segments 412, the first groove segment 411 and the second score groove 42 constitute a closed ring structure.

[0270] In the first direction F1, the width dimension of the groove bottom surface of the first groove segment 411 is W, and 0.4mm≤W≤0.75mm.

[0271] As shown in FIGS. 7-11, 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 the first score groove 41 and the second score groove 42, the first score groove 41 includes the first groove segment 411 and the two second groove segments 412, the end of the first groove segment 411 is respectively connected with the middle of the corresponding second groove segment 412, the first groove segment 411 extends along the third direction F3, the second groove segment 412 extends along the first direction F1, and the first groove segment 411 and the two second groove segments 412 form an H-shaped structure.

[0272] In the thickness direction (the second direction F2) of the first wall portion 11, the pressure relief component 40 has oppositely arranged first and second surfaces 40a and 40b, the first groove segment 411 includes a plurality of levels of grooves arranged in sequence from the first surface 40a toward the direction close to the second surface 40b, in adjacent two levels of grooves, the level of groove far away from the first surface 40a is arranged on the groove bottom surface of the level of groove close to the first surface 40a; wherein the level of groove farthest away from the first surface 40a in the plurality of levels of grooves is the first level of groove 4111, the minimum residual thickness of the first level of groove 4111 is the minimum residual thickness of the first groove segment 411, and the groove bottom surface of the first level of groove 4111 is the groove bottom surface of the first groove segment 411.

[0273] The second groove segment 412 is also a plurality of levels of grooves, and the second groove segment 412 is the same in shape as the first level of groove 4111 and has the same minimum residual thickness as the corresponding level of groove.

[0274] The first score groove 41 has the minimum residual thickness at the first groove segment 411, and the minimum residual thickness at the second groove segment 412 is equal to the minimum residual thickness at the first groove segment 411.

[0275] In the first direction F1, the width dimension of the groove bottom surface of the first groove segment 411 is W, and 0.3mm≤W≤0.5mm.

[0276] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limit them. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some or all of the technical features can be replaced equivalently. Such modifications or replacements do not change the essence of the corresponding technical solutions, which should be covered in the scope of the present application. In particular, the technical features mentioned in each embodiment can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, wherein, The application relates to a battery cell, comprising: an electrode assembly comprising at least one positive electrode tab and at least one negative electrode tab, the at least one positive electrode tab and the at least one negative electrode tab being stacked and forming a flat area, at least a portion of the positive electrode tab and at least a portion of the negative electrode tab being arranged in a first direction in the flat area; a housing for accommodating the electrode assembly, the housing comprising a first wall portion; a pressure relief component arranged on the first wall portion, the pressure relief component being provided with a first score groove, the pressure relief component being configured to be split along at least a portion of the first score groove when the battery cell is relieved of pressure; wherein the first score groove comprises a first groove segment extending along a straight trajectory, a length direction of the first groove segment being perpendicular to the first direction, a groove bottom surface of the first groove segment having a dimension W in the first direction, 0.3mm<=W<=0.8mm.

2. The battery cell of claim 1, wherein, The pressure relief component is welded and fixed with the first wall portion, the pressure relief component is mounted on the first wall portion, a dimension W of the groove bottom surface of the first groove segment in the first direction satisfies 0.4mm<=W<=0.75mm, and optionally, 0.44mm<=W<=0.65mm.

3. The battery cell of claim 1 or 2, wherein, A width of the first wall portion in the first direction is D, and 0.008<=W / D<=0.019 and 20mm<=D<=80mm are satisfied.

4. The battery cell of claim 2 or 3, wherein, The first score groove defines at least one predetermined pressure relief area, the pressure relief component is provided with a second score groove, the second score groove is configured to guide at least a portion of the predetermined pressure relief area to flip over, so as to open at least a portion of the predetermined pressure relief area.

5. The battery cell of claim 4, wherein, A residual thickness of the second score groove is greater than a residual thickness of the first score groove.

6. The battery cell of claim 4 or 5, wherein, A maximum width of the second score groove is not greater than a maximum width of the first score groove.

7. The battery cell of any one of claims 4-6, wherein, The first score groove further comprises two second groove segments, the two second groove segments are oppositely arranged, two ends of the first groove segment are respectively connected to one end of the two second groove segments, and the other end of the two second groove segments is connected to two ends of the second score groove, the first groove segment, the two second groove segments and the second score groove jointly define the predetermined pressure relief area.

8. The battery cell of claim 7, wherein, The second score groove is arranged in parallel and opposite to the first groove segment, and the second groove segment extends along a straight and / or arc trajectory.

9. The battery cell of claim 7, wherein, In a thickness direction of the first wall portion, the pressure relief component has oppositely arranged first and second surfaces, the first score groove and the second score groove are arranged on the first surface.

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

11. The battery cell of claim 1, wherein, The pressure relief component and the first wall portion are integrally formed, a dimension W of a groove bottom surface of the first groove segment in the first direction satisfies 0.3mm<=W<=0.5mm, and optionally, 0.35mm<=W<=0.45mm.

12. The battery cell of any one of claims 1-3, 11, wherein, The first score groove comprises the first groove segment and a second groove segment, the first groove segment is connected to the second groove segment, and the first groove segment and the second groove segment jointly define the predetermined pressure relief area.

13. The battery cell of claim 12, wherein, The first score groove comprises two first groove segments and one second groove segment, the two first groove segments are oppositely arranged, and the two first groove segments are connected with the second groove segment respectively, the connection position of the second groove segment with each first groove segment is deviated 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.

14. The battery cell of claim 12, wherein, The first score groove comprises one first groove segment and two second groove segments, the two second groove segments are oppositely arranged, the first groove segment connects the two second groove segments, the connection position of each second groove segment with the first groove segment is deviated 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 of claim 12, wherein, The plurality of groove segments comprise one first groove segment and four second groove segments, the two ends of the first groove segment are respectively connected with two second groove segments arranged at a preset included angle, and the first groove segment and the four second groove segments jointly define a predetermined pressure relief area.

16. The battery cell of any one of claims 11-15, 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 configured to guide at least part of the predetermined pressure relief area to be turned over to open at least part of the predetermined pressure relief area.

17. The battery cell of claim 16, wherein, Along the thickness direction of the first wall portion, the pressure relief component has oppositely arranged first and second surfaces, the first score groove is arranged on the first surface, and the second score groove is arranged on the second surface.

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

19. The battery cell of any one of claims 1-18, wherein, Along the thickness direction of the first wall portion, the pressure relief component has oppositely arranged first and second surfaces, the first groove segment comprises a plurality of levels of grooves arranged in sequence from the first surface to the direction close to the second surface, and in two adjacent levels of grooves, the level of groove far away from the first surface is arranged on the groove bottom surface of the level of groove close to the first surface. Among the plurality of levels of grooves, the level of groove farthest away from the first surface is a first level of groove, the minimum residual thickness of the first level of groove is the minimum residual thickness of the first groove segment, and the groove bottom surface of the first level of groove is the groove bottom surface of the first groove segment.

20. The battery cell of any one of claims 1-19, wherein, The first score groove is formed by stamping on the pressure relief component.

21. The battery cell of any one of claims 1-20, wherein, The shell comprises a shell body and an end cover, at least one side of the shell body has an opening, the end cover is connected with the shell body and is used for closing the opening, and the first wall portion is formed on the shell body.

22. The battery cell of claim 21, wherein, Both opposite sides of the shell body have openings, and two end covers are used for closing the openings on the corresponding sides.

23. The battery cell of any one of claims 1-22, wherein, The first wall portion is used for supporting the electrode assembly and is located below the electrode assembly.

24. A battery, wherein, The battery cell according to any one of claims 1-23 is included.

25. An electrical device, comprising: The battery according to claim 24 is used for providing electric energy for the electric device.

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