Battery cell, battery and electric device

Abstract

The invention discloses a battery monomer, a battery and a power utilization device, and the battery monomer comprises an electrode assembly which comprises a positive pole piece and a negative pole piece, and the positive pole piece and the negative pole piece form a straight area; the shell comprises a first wall part and two second wall parts, and the two second wall parts are located on the two sides of the straight area respectively in the first direction; the first wall part comprises a shell body and a pressure relief part, the shell body is arranged around the periphery of the pressure relief part, a nick groove is formed in the pressure relief part, the bottom wall of the nick groove is provided with a first groove wall section obliquely extending in the first direction, and an included angle is formed between the first groove wall section and the first direction. Therefore, the included angle is formed between the first groove wall section and the first direction, so that when the battery monomer expands and pulls the first wall part and the pressure relief part is subjected to pulling force, the stress angle of the nick groove can be changed, the stress of the nick groove can be reduced, the deformation resistance of the nick groove can be improved, and the cracking risk of the pressure relief part can be reduced; and the influence of external stress or deformation on the position of the nick groove of the pressure relief part is reduced.

Description

Technical Field

[0001] This application relates to the field of batteries, and more particularly to a battery cell, a battery, and an electrical device. Background Art

[0002] In the related art, a battery cell includes a housing and an electrode assembly. The electrode assembly is disposed inside the housing, and the housing is provided with a pressure relief portion. When the battery cell expands, the large surface of the housing deforms. The deformation of the large surface of the housing will pull the housing wall where the pressure relief portion is provided, causing the housing wall where the pressure relief portion is provided to deform, so that the pressure relief portion is subjected to a pulling force, which easily causes damage to the pressure relief portion and results in cracking of the pressure relief portion, affecting the normal use of the pressure relief portion. Summary of the Invention

[0003] This application aims to solve at least one of the technical problems existing in the prior art. For this purpose, an object of this application is to provide a battery cell. After the pressure relief portion of the battery cell is subjected to a pulling force, it can change the force application angle of the notch groove, reduce the force on the notch groove, improve the anti-deformation ability of the notch groove, and reduce the risk of cracking of the pressure relief portion.

[0004] This application further provides a battery.

[0005] This application further provides an electrical device.

[0006] In a first aspect, an embodiment of this application provides a battery cell, including:

[0007] An electrode assembly, including a positive electrode tab and a negative electrode tab. After the positive electrode tab and the negative electrode tab are stacked, a flat area is formed. At least a part of the positive electrode tab and at least a part of the negative electrode tab are stacked in the flat area along a first direction;

[0008] A housing for accommodating the electrode assembly. The housing includes a first wall portion and two second wall portions connected to the first wall portion. The two second wall portions are respectively located on both sides of the flat area along the first direction;

[0009] Wherein, the first wall portion includes a housing body and a pressure relief portion. The housing body is disposed around the outer periphery of the pressure relief portion. The pressure relief portion is formed with a notch groove. The bottom wall of the notch groove has a first groove wall section extending obliquely along the first direction. The first groove wall section forms an angle with the first direction.

[0010] In the above technical solution, by forming an angle between the first groove wall section and the first direction, when the battery cell expands and pulls the first wall portion, after the pressure relief portion is subjected to a pulling force, the first groove wall section can decompose the force, change the force application angle of the notch groove, reduce the force on the notch groove, improve the anti-deformation ability of the notch groove, reduce the risk of cracking of the pressure relief portion, and reduce the influence of external force or deformation on the position of the notch groove of the pressure relief portion.

[0011] In some embodiments, the angle between the first groove wall segment and the first direction is greater than or equal to 20° and less than or equal to 70°.

[0012] In the above technical solution, by making the angle between the first groove wall segment and the first direction greater than or equal to 20° and less than or equal to 70°, the angle between the first groove wall segment and the first direction can be made appropriate. When the electrode assembly expands, after the first groove wall segment is stressed, the first groove wall segment can decompose the stress, which is beneficial to reducing the stress on the notch groove, further improving the anti-deformation ability of the notch groove, and further reducing the risk of cracking of the pressure relief part.

[0013] In some embodiments, the first groove wall segment is in multiple segments, and the multiple segments of the first groove wall segment are arranged in sequence along a second direction perpendicular to the first direction.

[0014] In the above technical solution, by providing multiple segments of the first groove wall segment, the multiple segments of the first groove wall segment can simultaneously decompose the stress into component forces along the first direction and the second direction, thereby further reducing the stress on the notch groove, further improving the anti-deformation ability of the notch groove, further reducing the risk of cracking of the pressure relief part, further reducing the influence of external force or deformation on the position of the notch groove of the pressure relief part, further reducing the risk of liquid leakage of the pressure relief part, being beneficial to maintaining the normal use of the pressure relief part, and further improving the fatigue life of the pressure relief part. Moreover, it is beneficial for the pressure relief part to open the valve fastest when gas is generated at a certain position of the battery cell.

[0015] In some embodiments, the bottom wall of the notch groove further has a second groove wall segment, and the second groove wall segment is connected between adjacent two first groove wall segments.

[0016] In the above technical solution, by connecting the second groove wall segment between adjacent two first groove wall segments, the multiple segments of the first groove wall segment can be connected to form a strip structure, which is beneficial to simplifying the notch groove.

[0017] In some embodiments, the thickness of the second groove wall segment is greater than the thickness of the first groove wall segment.

[0018] In the above technical solution, by setting the thickness of the second groove wall segment to be greater than the thickness of the first groove wall segment, the second groove wall segment can meet the structural strength requirements, which is beneficial to improving the overall structural strength of the notch groove, improving the anti-deformation ability of the notch groove, and further reducing the risk of cracking of the pressure relief part.

[0019] In some embodiments, the bottom wall of the notch groove further has an arc-shaped third groove wall segment, and the third groove wall segment is connected between the adjacent first groove wall segment and the second groove wall segment.

[0020] In the above technical solution, since the third groove wall section is an arc structure and the third groove wall section is connected between the adjacent first groove wall section and the second groove wall section, a transition section groove wall can be formed between the first groove wall section and the second groove wall section. After the pressure relief part is stressed, it is beneficial to reduce the risk of stress concentration on the bottom wall of the notch groove, further improve the anti-deformation ability of the notch groove, and further reduce the risk of cracking of the pressure relief part.

[0021] In some embodiments, the third groove wall section is a circular arc structure.

[0022] In the above technical solution, by setting the third groove wall section as a circular arc structure, a circular arc transition section groove wall can be formed between the first groove wall section and the second groove wall section, enabling a smooth transition between the first groove wall section and the second groove wall section. After the pressure relief part is stressed, it is more beneficial to reduce the risk of stress concentration on the bottom wall of the notch groove, further improve the anti-deformation ability of the notch groove, and further reduce the risk of cracking of the pressure relief part.

[0023] In some embodiments, in the direction from the first groove wall section to the second groove wall section, the thickness of the third groove wall section gradually increases.

[0024] In the above technical solution, by gradually increasing the thickness dimension of the third groove wall section in the direction from the first groove wall section to the second groove wall section, a thickness-gradual structure can be formed for the groove wall between the first groove wall section and the second groove wall section, enabling a smooth and gentle transition between the first groove wall section and the second groove wall section. After the pressure relief part is stressed, it is more beneficial to reduce the risk of stress concentration on the bottom wall of the notch groove, further improve the anti-deformation ability of the notch groove, and further reduce the risk of cracking of the pressure relief part.

[0025] In some embodiments, the second groove wall section is arc-shaped and protrudes towards the outside of the shell body along the first direction.

[0026] In the above technical solution, by protruding the second groove wall section towards the outside of the shell body along the first direction, the notch groove can be configured as a wavy structure, which can simplify the structural shape of the notch groove, facilitate the machining of the notch groove on the pressure relief part, improve the production efficiency of the pressure relief part, and thus improve the production efficiency of the battery cell.

[0027] In some embodiments, the second groove wall section is circular arc-shaped, and the radius of the second groove wall section is greater than or equal to 1 mm and less than or equal to 10 mm.

[0028] In the above technical solution, by setting the second groove wall section as a circular arc structure, a smooth transition can be formed at the bending part of the notch groove. When the pressure relief part is stressed, the risk of stress concentration at the second groove wall section can be reduced, which is more beneficial to reducing the risk of stress concentration on the bottom wall of the notch groove, further improving the anti-deformation ability of the notch groove, and further reducing the risk of cracking of the pressure relief part.

[0029] In some embodiments, the second groove wall segment has a linear structure and extends along a second direction.

[0030] In the above technical solution, by setting the second groove wall segment to have a linear structure, the structural shape of the notch groove can be further simplified, the processing difficulty of the notch groove can be reduced, it is more convenient to process the notch groove on the pressure relief part, the production efficiency of the pressure relief part can be further improved, and thus the production efficiency of the battery cell can be further improved.

[0031] In some embodiments, the ratio of the maximum thickness of the second groove wall segment to the minimum thickness of the first groove wall segment is greater than or equal to 1.1 and less than or equal to 1.8.

[0032] In the above technical solution, by the ratio of the maximum thickness of the second groove wall segment to the minimum thickness of the first groove wall segment being greater than or equal to 1.1 and less than or equal to 1.8, the structural strength at the second groove wall segment is not less than the structural strength at the first groove wall segment, which can enable the second groove wall segment to meet the structural strength requirements, is more conducive to improving the overall structural strength of the notch groove, can further improve the anti-deformation ability of the notch groove, and further reduce the risk of cracking of the pressure relief part.

[0033] In some embodiments, the ratio of the maximum thickness of the second groove wall segment to the maximum thickness of the housing body is greater than or equal to 0.05 and less than or equal to 0.5.

[0034] In the above technical solution, by the ratio of the maximum thickness of the second groove wall segment to the maximum thickness of the housing body being greater than or equal to 0.05 and less than or equal to 0.5, when the battery cell undergoes thermal runaway, the pressure relief part can crack at the second groove wall segment and the first groove wall segment to achieve the pressure relief effect and reduce the risk of explosion of the battery cell.

[0035] In some embodiments, the housing body is formed with two reinforcing ribs, and both ends of the notch groove are respectively connected to the two reinforcing ribs.

[0036] In the above technical solution, by both ends of the notch groove being respectively connected to the two reinforcing ribs, the reinforcing ribs play a role in structural reinforcement, and when the bottom wall of the notch groove in the pressure relief part cracks and releases pressure, the risk of continuously tearing the housing body towards both ends of the notch groove can be reduced.

[0037] In some embodiments, the two reinforcing ribs are opposite and spaced apart, and the reinforcing ribs are arc-shaped.

[0038] In the above technical solution, by setting the reinforcing ribs to have an arc-shaped structure, the structural strength of the reinforcing ribs can be improved, and when the bottom wall of the notch groove in the pressure relief part cracks and releases pressure, the risk of continuously tearing the housing body towards both ends of the notch groove can be further reduced.

[0039] In some embodiments, along the first direction, the pressure relief part is located at the middle position of the housing body.

[0040] In the above technical solution, since the pressure relief portion is located in the middle position of the housing body along the first direction, the force on each position of the scoring groove can be made uniform, the force on the scoring groove can be reduced, which is beneficial to tearing at each position of the scoring groove under the same bursting pressure, and further increases the fatigue life of the pressure relief portion.

[0041] In some embodiments, the housing body has a housing bottom wall opposite to the open end of the outer shell, and the pressure relief portion is provided on the housing bottom wall.

[0042] In the above technical solution, by providing the pressure relief portion on the housing bottom wall, the effect of the battery cell discharging pressure towards the bottom can be achieved, and the risk of high-temperature and high-pressure substances ejected from the battery cell harming the surrounding personnel can be reduced.

[0043] In some embodiments, the housing body has a housing side wall adjacent to the open end of the outer shell, and the pressure relief portion is provided on the housing side wall.

[0044] In the above technical solution, by providing the pressure relief portion on the housing side wall, the effect of the battery cell discharging pressure towards the side can be achieved. During the pressure relief process of the battery cell, the high-temperature and high-pressure substances in the battery cell can be quickly discharged from the battery cell.

[0045] In a second aspect, an embodiment of the present application further provides a battery, including the above battery cell.

[0046] In a third aspect, an embodiment of the present application further provides an electrical device, including the above battery.

[0047] The additional aspects and advantages of the present application will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The above and / or additional aspects and advantages of the present application will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, where:

[0049] Figure 1 is a schematic diagram of an electrical device according to an embodiment of the present application;

[0050] Figure 2 is an exploded view of a battery according to an embodiment of the present application;

[0051] Figure 3 is a schematic diagram of a battery cell according to the first embodiment of the present application;

[0052] Figure 4 is another perspective schematic diagram of a battery cell according to the first embodiment of the present application;

[0053] Figure 5 is an exploded view of a battery cell according to the first embodiment of the present application;

[0054] Figure 6 It is a schematic diagram of a battery cell according to the second embodiment of the present application;

[0055] Figure 7 It is a schematic diagram in which the pressure relief part is arranged on the bottom wall of the shell according to the embodiment of the present application.

[0056] Reference numerals:

[0057] Battery cell 200;

[0058] Electrode assembly 300; flat area 301;

[0059] Outer shell 60; end cap 20; installation cavity 30;

[0060] First wall portion 11; shell body 111; pressure relief portion 112; notch groove 113; first groove wall segment 114; second groove wall segment 115; third groove wall segment 116; reinforcing rib 117; shell bottom wall 118; shell side wall 119; open end 120;

[0061] Second wall portion 12;

[0062] Battery 400; box body 401; first box body 402; second box body 403;

[0063] Electrical device 500; controller 600; motor 700. Detailed implementation manners

[0064] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0065] Unless otherwise defined, all technical and scientific terms used in the present application have the same meanings as those commonly understood by those skilled in the technical field to which the present application belongs; the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of the present application or the above drawings are used to distinguish different objects and are not used to describe a specific order or primary-secondary relationship.

[0066] Reference to "embodiment" in this application means that the specific features, structures, or characteristics described in connection with the embodiment may be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0067] In the description of this application, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected", "connected to", and "attached" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0068] The term "and / or" in this application is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally represents an "or" relationship between the associated objects before and after.

[0069] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, in different embodiments, the detailed description of the same components is omitted. It should be understood that the thickness, length, width, etc. of various components in the embodiments of this application shown in the drawings, as well as the overall thickness, length, width, etc. of the integrated device, are only for illustrative purposes and should not constitute any limitation to this application.

[0070] The term "a plurality of" appearing in this application refers to two or more (including two).

[0071] In the embodiments of this application, the battery cell can be a secondary battery, which refers to a battery cell that can be activated by charging after discharging so as to continue to be used.

[0072] 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-metal hydride battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiments of this application are not limited thereto.

[0073] The battery mentioned in the embodiments of this application refers to a single physical module including one or more battery cells to provide a higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, parallel, or in a hybrid connection through a busbar component.

[0074] In some embodiments, the battery can be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0075] In some embodiments, the battery may be a battery pack, which includes a box body and battery cells, and the battery cells or battery modules are accommodated in the box body.

[0076] In some embodiments, the box body may be part of the chassis structure of a vehicle. For example, part of the box body may form at least part of the floor of the vehicle, or part of the box body may form at least part of the cross beams and longitudinal beams of the vehicle.

[0077] In some embodiments, the battery may be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0078] The development of battery technology needs to consider various design factors simultaneously. For example, performance parameters such as energy density, cycle life, discharge capacity, charge and discharge rate, etc. In addition, the safety performance of the battery also needs to be considered.

[0079] In the battery cell, to ensure the safety performance of the battery cell, a pressure relief part may be provided on the outer 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 part to improve the safety of the battery cell.

[0080] During the charge and discharge process of the battery cell, the electrode assembly will undergo hard expansion, resulting in the bulging and deformation of the outer shell. The pressure relief part is provided on the outer shell, especially some pressure relief parts are provided on the wall part closer to the electrode assembly. The expansion of the electrode assembly will deform the wall part where the pressure relief part is located, thereby pulling the notch of the pressure relief part, resulting in damage at the notch of the pressure relief part and further leakage of liquid. As a result, the pressure relief part may be damaged when the internal pressure of the battery cell does not reach the detonation pressure of the pressure relief part, leading to the failure of the pressure relief part and relatively low reliability of the pressure relief part.

[0081] In view of this, an embodiment of the present application provides a battery cell, including an electrode assembly and an outer shell for accommodating the electrode assembly. The outer shell includes a first wall part and two second wall parts connected to the first wall part. The first wall part includes a shell body and a pressure relief part. The shell body is arranged around the outer periphery of the pressure relief part, and the pressure relief part is formed with a notch groove. The bottom wall of the notch groove has a first groove wall section extending obliquely along a first direction, and the first groove wall section forms an angle with the first direction.

[0082] In such a battery cell, by forming an angle between the first groove wall section and the first direction, when the battery cell expands and pulls the first wall part, after the pressure relief part is subjected to a pulling force, the force application angle of the notch groove can be changed, the force on the notch groove can be reduced, the anti-deformation ability of the notch groove can be improved, the risk of cracking of the pressure relief part can be reduced, and the influence of external force or deformation on the position of the notch groove of the pressure relief part can be reduced.

[0083] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0084] The electrical device can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or an extended-range electric vehicle, etc.; the spacecraft includes an airplane, a rocket, a space shuttle, a spaceship, etc.; the electric toy includes a stationary or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool and a railway electric tool, for example, an electric drill, an electric grinding wheel, an electric wrench, an electric screwdriver, a hammer drill, an impact drill, a concrete vibrator, a planer, etc. The embodiments of the present application do not impose special restrictions on the above electrical devices.

[0085] For the convenience of description, the following embodiments take the electrical device as a vehicle as an example for description.

[0086] Please refer to Figure 1 , Figure 1 , which is a schematic structural diagram of a vehicle provided by some embodiments of the present application. A battery 400 is disposed inside the vehicle. The battery 400 can be disposed at the bottom, the head or the tail of the vehicle. The battery 400 can be used for power supply of the vehicle. For example, the battery 400 can be used as the operating power source of the vehicle.

[0087] The vehicle may further include a controller 600 and a motor 700. The controller 600 is used to control the battery 400 to supply power to the motor 700. For example, it is used for the working power requirements during the start, navigation and driving of the vehicle.

[0088] In some embodiments of the present application, the battery 400 can not only be used as the operating power source of the vehicle, but also be used as the driving power source of the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0089] Please refer to Figure 2 , Figure 2 , which is an exploded view of the battery 400 provided by some embodiments of the present application. The battery 400 includes battery cells 200 and a box body 401. The box body 401 is used to accommodate the battery cells 200.

[0090] Among them, the battery box 401 is a component for accommodating the battery cells 200. The battery box 401 provides a placement space for the battery cells 200, and the battery box 401 can adopt various structures. In some embodiments, the battery box 401 may include a first box body 402 and a second box body 403. The first box body 402 and the second box body 403 cover each other to define a placement space for accommodating the battery cells 200. The first box body 402 and the second box body 403 can be of various shapes, such as a cuboid, a cylinder, etc. The first box body 402 can be a hollow structure with one side open, and the second box body 403 can also be a hollow structure with one side open. When the open side of the second box body 403 covers the open side of the first box body 402, the battery box 401 with a placement space is formed. It can also be that the first box body 402 is a hollow structure with one side open, and the second box body 403 is a plate-like structure. When the second box body 403 covers the open side of the first box body 402, the battery box 401 with a placement space is formed. As an example, the battery cell 200 can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell, or a battery cell 200 of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, and a multi-prismatic battery. The multi-prismatic battery is, for example, a hexagonal-prismatic battery, etc. There is no special limitation in this application.

[0091] In the battery 400, the battery cells 200 can be one or multiple. If there are multiple battery cells 200, the multiple battery cells 200 can be connected in series, in parallel, or in a series-parallel combination. A series-parallel combination means that there are both series and parallel connections among the multiple battery cells 200. It can be that multiple battery cells 200 are first connected in series, in parallel, or in a series-parallel combination to form a battery module, and then multiple battery modules are connected in series, in parallel, or in a series-parallel combination to form an integral body and are accommodated in the battery box 401. It can also be that all the battery cells 200 are directly connected in series, in parallel, or in a series-parallel combination together, and then the integral body formed by all the battery cells 200 is accommodated in the battery box 401.

[0092] Please refer to Figure 3 、 Figure 5 and Figure 6 , the battery cell 200 may include a housing 60 and an electrode assembly 300.

[0093] The housing 60 is used to accommodate components such as the electrode assembly 300 and the electrolyte. The housing 60 can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite housing), or an aluminum-plastic film, etc. As an example, the battery cell 200 may include an end cap 20 and a housing 60.

[0094] The housing 60 can be a hollow structure with an opening formed at one end, or the housing 60 can also be a hollow structure with openings formed at opposite ends. The material of the housing 60 can be various, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0095] The end cap 20 is a component that closes the opening of the housing 60 to isolate the internal environment of the battery cell 200 from the external environment. The end cap 20 and the housing 60 together define a receiving space for accommodating the electrode assembly 300, the electrolyte, and other components. The end cap 20 can be connected to the housing 60 by welding or crimping to close the opening of the housing 60. The shape of the end cap 20 can be adapted to the shape of the housing 60. For example, if the housing 60 has a cuboid structure, the end cap 20 is a rectangular plate-like structure adapted to the housing 60. The material of the end cap 20 can also be various, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0096] In the battery cell 200, there can be one or two end caps 20. In an embodiment where the housing 60 is a hollow structure with openings formed at both ends, two end caps 20 can be correspondingly provided. The two end caps 20 respectively close the two openings of the housing 60, and the two end caps 20 and the housing 60 together define the receiving space. In an embodiment where the housing 60 is a hollow structure with an opening formed at one end, one end cap 20 can be correspondingly provided. The end cap 20 closes the opening at one end of the housing 60, and one end cap 20 and the housing 60 together define the receiving space.

[0097] The electrode assembly 300 includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell 200, active ions (such as lithium ions) intercalate and deintercalate back and forth between the positive electrode and the negative electrode. The separator is disposed between the positive electrode and the negative electrode, which can prevent the short circuit between the positive and negative electrodes and at the same time allow the active ions to pass through.

[0098] In some embodiments, the positive electrode can be a positive electrode tab, and the positive electrode tab can include a positive electrode current collector and a positive electrode active material region provided on at least one surface of the positive electrode current collector. The positive electrode active material region has a positive electrode active material.

[0099] As an example, the positive electrode current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode active material region is provided on either or both of the two opposite surfaces of the positive electrode current collector.

[0100] In some embodiments, the negative electrode can be a negative electrode tab, and the negative electrode tab can include a negative electrode current collector and a negative electrode active material region provided on at least one surface of the negative electrode current collector.

[0101] As an example, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode active material region is provided on either of the two opposite surfaces of the negative electrode current collector.

[0102] In some embodiments, the material of the positive electrode current collector can be aluminum, and the material of the negative electrode current collector can be copper.

[0103] In some embodiments, the electrode assembly 300 further includes a separator disposed between the positive electrode and the negative electrode.

[0104] In some embodiments, the separator is a separator membrane. The present application does not particularly limit the type of the separator membrane, and any well-known porous structure separator membrane with good chemical stability and mechanical stability can be selected.

[0105] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive electrode and the negative electrode, and simultaneously functions to transport ions and isolate the positive and negative electrodes.

[0106] In some embodiments, the battery cell 200 further includes an electrolyte that functions to conduct ions between the positive and negative electrodes. The present application does not specifically limit the type of the electrolyte, and it can be selected according to requirements. The electrolyte can be liquid, gel-like, or solid.

[0107] In some embodiments, the electrode assembly 300 has a wound structure. The positive electrode sheet and the negative electrode sheet are wound into a wound structure.

[0108] In some embodiments, the electrode assembly 300 has a stacked structure.

[0109] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets can be respectively provided, and the plurality of positive electrode sheets and the plurality of negative electrode sheets are alternately stacked.

[0110] As an example, a plurality of positive electrode sheets can be provided, and the negative electrode sheet is folded to form a plurality of stacked folding segments, and a positive electrode sheet is clamped between adjacent folding segments.

[0111] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folding segments.

[0112] As an example, a plurality of separators can be provided and are respectively disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0113] As an example, the separator can be continuously provided and is disposed between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0114] In some embodiments, the shape of the electrode assembly 300 can be flat or multi-prismatic, etc.

[0115] In some embodiments, the electrode assembly 300 is provided with tabs, and the tabs can conduct current out of the electrode assembly 300. The tabs include a positive tab and a negative tab.

[0116] The electrode assembly 300 includes a plurality of electrode sheets arranged in a wound manner, and the outer peripheral surface of the electrode assembly 300 includes a flat area 301.

[0117] A plurality of electrode tabs arranged in a wound configuration, namely, a positive electrode tab and a negative electrode tab are stacked and then wound around a set axis to form an electrode assembly 300. The flat region 301 refers to the portion of the electrode tab that extends along a plane during winding. The two opposite side surfaces of the electrode assembly 300 in the first direction are formed as the flat region 301.

[0118] Reference will be made below Figures 3 - 7 to describe the battery cell 200 according to an embodiment of the present application.

[0119] The battery cell 200 according to an embodiment of the present application includes: an electrode assembly 300 including a positive electrode tab and a negative electrode tab. After the positive electrode tab and the negative electrode tab are stacked, a flat region 301 is formed. At least a part of the positive electrode tab and at least a part of the negative electrode tab are stacked in the flat region 301 in the first direction; a housing 60 for accommodating the electrode assembly 300. The housing 60 includes a first wall portion 11 and two second wall portions 12 connected to the first wall portion 11. The two second wall portions 12 are respectively located on both sides of the flat region 301 in the first direction; wherein, the first wall portion 11 includes a housing body 111 and a pressure relief portion 112. The housing body 111 is disposed around the outer periphery of the pressure relief portion 112. The pressure relief portion 112 is formed with a notch groove 113. The bottom wall of the notch groove 113 has a first groove wall segment 114 that extends obliquely in the first direction. The first groove wall segment 114 forms an angle with the first direction.

[0120] Among them, the electrode assembly 300 includes a positive electrode tab and a negative electrode tab. For example: the electrode assembly 300 includes 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 are stacked to form the electrode assembly 300. After the positive electrode tab and the negative electrode tab are stacked, a flat region 301 is formed. In the flat region 301, at least a part of the positive electrode tab and at least a part of the negative electrode tab are stacked in the first direction. Thus, the expansion of the electrode assembly 300 is mostly reflected in the first direction. When the battery cell 200 is placed Figure 3 in the direction shown, the first direction refers to Figure 3 the Z direction in. The outer peripheral surface of the electrode assembly 300 has a flat region 301.

[0121] The electrode assembly 300 can also be of a wound type. The positive electrode tab and the negative electrode tab of the electrode assembly 300 are stacked with a separator film and then wound into a shape, and a flat region 301 is formed. In the flat region 301, a part of the positive electrode tab and a part of the negative electrode tab are stacked in the first direction. For example, after winding, each layer of the positive electrode tab and each layer of the negative electrode tab can be penetrated by an axis extending in the first direction. Thus, the expansion of the electrode assembly 300 is mostly reflected in the first direction.

[0122] The housing 60 defines an open mounting cavity 30, and the electrode assembly 300 of the battery cell 200 is mounted in the mounting cavity 30. The housing 60 includes a first wall portion 11 and two second wall portions 12. The two second wall portions 12 are respectively located on both sides of the electrode assembly 300 in the first direction. The expanded part of the electrode assembly 300 acts on the second wall portions 12. The first wall portion 11 is located between the two second wall portions 12, and the first wall portion 11 is connected between the two second wall portions 12. The first wall portion 11 and the two second wall portions 12 constitute the housing 60 of the above embodiment.

[0123] The first wall portion 11 includes a housing body 111 and a pressure relief portion 112. The housing body 111 is disposed around the outer periphery of the pressure relief portion 112, and the pressure relief portion 112 is fixedly provided on the housing body 111. The pressure relief portion 112 can be an explosion-proof valve, or the first wall portion 11 has a scoring structure to form the pressure relief portion 112 on the first wall portion 11, and the pressure relief portion 112 is formed with a scoring groove 113. When the internal pressure threshold of the mounting cavity 30 reaches a certain value, the scoring groove 113 of the pressure relief portion 112 opens, and the gas and substances inside the battery cell 200 are discharged from the pressure relief portion 112 to achieve the pressure relief effect. The design of this pressure threshold varies according to different design requirements, and this pressure threshold may depend on one or more materials among the positive electrode plate, negative electrode plate, electrolyte, and separator in the battery cell 200.

[0124] When the electrode assembly 300 expands, the influence of the first wall portion 11 by the electrode assembly 300 is less than that of the second wall portion 12 by the electrode assembly 300. Since the pressure relief portion 112 is located on the first wall portion 11, the risk of the electrode assembly 300 expansion blocking or damaging the pressure relief portion 112 can be reduced.

[0125] As Figure 7 shown, the bottom wall of the scoring groove 113 has a first groove wall section 114, and the first groove wall section 114 extends obliquely in the first direction, and the first groove wall section 114 forms an angle with the first direction.

[0126] When the electrode assembly expands, the electrode assembly presses against the housing of the battery cell and pushes the housing outwards, causing the housing to deform. The housing is the main stress surface and deforms greatly. When the housing deforms, the deformation of the housing will pull the pressure relief portion, so that the pressure relief portion is subjected to a pulling force, which easily causes damage to the pressure relief portion and affects the normal use of the pressure relief portion.

[0127] In the present application, by making the first groove wall segment 114 extend obliquely in the first direction and the first groove wall segment 114 form an angle with the first direction, when the electrode assembly 300 expands, the flat area 301 of the electrode assembly 300 abuts against the second wall portion 12 and outwardly supports the outer shell 60, causing the outer shell 60 to deform. The deformation of the second wall portion 12 of the outer shell 60 is large. When the second wall portion 12 deforms, the deformation of the second wall portion 12 will pull the first wall portion 11 along the first direction, causing the first wall portion 11 to deform. Since the first groove wall segment 114 forms an angle with the first direction, after the first groove wall segment 114 is stressed, the first groove wall segment 114 can decompose the stress into component forces along the first direction and the second direction, and can change the stress angle of the notch groove 113. The second direction is perpendicular to the first direction, and the second direction is the length direction of the first wall portion 11. As Figure 4 , Figure 6 and Figure 7 shown, the second direction is Figure 4 , Figure 6 and Figure 7 the X direction in, thereby reducing the stress on the notch groove 113, improving the anti-deformation ability of the notch groove 113, reducing the risk of cracking of the pressure relief portion 112, reducing the influence of external stress or deformation on the position of the notch groove 113 of the pressure relief portion 112, reducing the risk of liquid leakage of the pressure relief portion 112, facilitating the normal use of the pressure relief portion 112, and further improving the fatigue life of the pressure relief portion 112.

[0128] In the above technical solution, by forming an angle between the first groove wall segment 114 and the first direction, when the battery cell 200 expands and pulls the first wall portion 11, after the pressure relief portion 112 is subjected to a pulling force, the first groove wall segment 114 can decompose the stress, change the stress angle of the notch groove 113, reduce the stress on the notch groove 113, improve the anti-deformation ability of the notch groove 113, and reduce the risk of cracking of the pressure relief portion 112 and the influence of external stress or deformation on the position of the notch groove 113 of the pressure relief portion 112.

[0129] According to some embodiments of the present application, as Figure 7 shown, the angle between the first groove wall segment 114 and the first direction is greater than or equal to 20° and less than or equal to 70°.

[0130] Among them, the first groove wall segment 114 can be linear, or the first groove wall segment 114 is similar to a straight line, such as Figure 7As shown, the included angle between the first groove wall segment 114 and the first direction is β, satisfying the relation: 20° ≤ β ≤ 70°, and β can be values such as 20°, 30°, 35°, 40°, 70°. By making the included angle between the first groove wall segment 114 and the first direction greater than or equal to 20° and less than or equal to 70°, the included angle between the first groove wall segment 114 and the first direction can be made appropriate. When the electrode assembly 300 expands, after the first groove wall segment 114 is stressed, the first groove wall segment 114 can decompose the stress, which is beneficial to reducing the stress on the notch groove 113, can further improve the anti-deformation ability of the notch groove 113, and further reduce the cracking risk of the pressure relief part 112.

[0131] In the above technical solution, by making the included angle between the first groove wall segment 114 and the first direction greater than or equal to 20° and less than or equal to 70°, the included angle between the first groove wall segment 114 and the first direction can be made appropriate. When the electrode assembly 300 expands, after the first groove wall segment 114 is stressed, the first groove wall segment 114 can decompose the stress, which is beneficial to reducing the stress on the notch groove 113, can further improve the anti-deformation ability of the notch groove 113, and further reduce the cracking risk of the pressure relief part 112.

[0132] According to some embodiments of the present application, as Figure 7 shown, the first groove wall segment 114 can be multiple segments, and the multiple segments of the first groove wall segment 114 are arranged in sequence along a second direction perpendicular to the first direction.

[0133] Among them, the first groove wall segment 114 can be set as multiple segments, and the multiple segments of the first groove wall segment 114 are arranged in sequence along the second direction. Adjacent two first groove wall segments 114 can be arranged at intervals. The number of the multiple segments of the first groove wall segment 114 can be reasonably selected and set according to the length of the wall of the first wall portion 11 provided with the pressure relief part 112. By setting the multiple segments of the first groove wall segment 114, when the first wall portion 11 deforms, after the multiple segments of the first groove wall segment 114 are stressed, the multiple segments of the first groove wall segment 114 can simultaneously decompose the stress into component forces along the first direction and the second direction, thereby further reducing the stress on the notch groove 113, can further improve the anti-deformation ability of the notch groove 113, further reduce the cracking risk of the pressure relief part 112, further reduce the influence of external stress or deformation on the position of the notch groove 113 of the pressure relief part 112, further reduce the liquid leakage risk of the pressure relief part 112, is beneficial to maintaining the normal use of the pressure relief part 112, and further improves the fatigue life of the pressure relief part 112. And, by setting the multiple segments of the first groove wall segment 114, it is beneficial for the pressure relief part 112 to open the valve fastest when gas is generated at a certain position of the battery cell 200.

[0134] In the above technical solution, by providing multiple first groove wall segments 114, the multiple first groove wall segments 114 can simultaneously decompose the force into component forces in the first direction and the second direction, thereby further reducing the force on the notch groove 113, further enhancing the anti-deformation ability of the notch groove 113, further reducing the risk of cracking of the pressure relief portion 112, further reducing the influence of external force or deformation on the position of the notch groove 113 of the pressure relief portion 112, further reducing the risk of liquid leakage in the pressure relief portion 112, which is beneficial to maintaining the normal use of the pressure relief portion 112, and further enhancing the fatigue life of the pressure relief portion 112. Moreover, it is beneficial for the pressure relief portion 112 to open the valve most quickly when gas is generated at a certain position of the battery cell 200.

[0135] Further, a part of the first groove wall segments 114 in the multiple first groove wall segments 114 are parallel to each other, and another part of the first groove wall segments 114 are parallel to each other, and the extension lines of adjacent two first groove wall segments 114 form an angle. In this way, when the first wall portion 11 is deformed and the multiple first groove wall segments 114 are stressed, the multiple first groove wall segments 114 can simultaneously decompose the force into component forces in the first direction and the second direction, effectively improving the force on the notch groove 113, further enhancing the anti-deformation ability of the notch groove 113, and further reducing the risk of cracking of the pressure relief portion 112.

[0136] According to some embodiments of the present application, as Figure 7 shown, the bottom wall of the notch groove 113 further has a second groove wall segment 115, and the second groove wall segments 115 are connected between adjacent two first groove wall segments 114.

[0137] Among them, the bottom wall of the notch groove 113 may further have a second groove wall segment 115, and the second groove wall segment 115 is connected between adjacent two first groove wall segments 114, which can connect the multiple first groove wall segments 114 to form a strip structure, facilitating the simplification of the notch groove 113.

[0138] In the above technical solution, by connecting the second groove wall segments 115 between adjacent two first groove wall segments 114, the multiple first groove wall segments 114 can be connected to form a strip structure, which is beneficial to simplifying the notch groove 113.

[0139] According to some embodiments of the present application, as Figure 7 shown, the thickness of the second groove wall segment 115 is greater than the thickness of the first groove wall segment 114.

[0140] Among them, the thickness dimension of the second groove wall segment 115 is greater than the thickness dimension of the first groove wall segment 114, which can also be understood as that the minimum thickness dimension of the second groove wall segment 115 is greater than the maximum thickness dimension of the first groove wall segment 114. As Figure 7As shown, since the second groove wall segment 115 is perpendicular or substantially perpendicular to the first direction. When the electrode assembly 300 expands, the flat area 301 of the electrode assembly 300 abuts against the second wall portion 12 and pushes the outer shell 60 outwards. The deformation of the second wall portion 12 will pull the first wall portion 11 along the first direction. And since the second groove wall segment 115 is perpendicular or substantially perpendicular to the first direction, compared with the force on the first groove wall segment 114, the force on the second groove wall segment 115 will be greater than the force on the first groove wall segment 114. Therefore, by setting the thickness of the second groove wall segment 115 to be greater than the thickness of the first groove wall segment 114, so that the structural strength at the second groove wall segment 115 is not less than the structural strength at the first groove wall segment 114, the second groove wall segment 115 can meet the structural strength requirements, which is beneficial to improving the overall structural strength of the notch groove 113, can improve the anti-deformation ability of the notch groove 113, and further reduce the cracking risk of the pressure relief portion 112.

[0141] In the above technical solution, by setting the thickness of the second groove wall segment 115 to be greater than the thickness of the first groove wall segment 114, the second groove wall segment 115 can meet the structural strength requirements, which is beneficial to improving the overall structural strength of the notch groove 113, can improve the anti-deformation ability of the notch groove 113, and further reduce the cracking risk of the pressure relief portion 112.

[0142] According to some embodiments of the present application, as Figure 7 shown, the bottom wall of the notch groove 113 further has an arc-shaped third groove wall segment 116, and the third groove wall segment 116 is connected between the adjacent first groove wall segment 114 and the second groove wall segment 115.

[0143] Among them, the bottom wall of the notch groove 113 has a third groove wall segment 116, the third groove wall segment 116 is an arc-shaped structure, and the third groove wall segment 116 is connected between the adjacent first groove wall segment 114 and the second groove wall segment 115. By setting the third groove wall segment 116 as an arc-shaped structure, a transition section groove wall can be formed between the first groove wall segment 114 and the second groove wall segment 115. After the pressure relief portion 112 is stressed, it is beneficial to reduce the risk of stress concentration on the bottom wall of the notch groove 113, can further improve the anti-deformation ability of the notch groove 113, and further reduce the cracking risk of the pressure relief portion 112.

[0144] In the above technical solution, by the third groove wall segment 116 being an arc-shaped structure and the third groove wall segment 116 being connected between the adjacent first groove wall segment 114 and the second groove wall segment 115, a transition section groove wall can be formed between the first groove wall segment 114 and the second groove wall segment 115. After the pressure relief portion 112 is stressed, it is beneficial to reduce the risk of stress concentration on the bottom wall of the notch groove 113, can further improve the anti-deformation ability of the notch groove 113, and further reduce the cracking risk of the pressure relief portion 112.

[0145] According to some embodiments of the present application, as Figure 7As shown, the third groove wall segment 116 has an arc-shaped structure.

[0146] Among them, the third groove wall segment 116 can be set to an arc-shaped structure, and the length of the third groove wall segment 116 can be reasonably selected and set according to actual conditions. By setting the third groove wall segment 116 to an arc-shaped structure, an arc transition section groove wall can be formed between the first groove wall segment 114 and the second groove wall segment 115, enabling a smooth transition between the first groove wall segment 114 and the second groove wall segment 115. After the pressure relief part 112 is stressed, it is more conducive to reducing the risk of stress concentration on the bottom wall of the notch groove 113, can further improve the anti-deformation ability of the notch groove 113, and further reduce the risk of cracking of the pressure relief part 112.

[0147] In the above technical solution, by setting the third groove wall segment 116 to an arc-shaped structure, an arc transition section groove wall can be formed between the first groove wall segment 114 and the second groove wall segment 115, enabling a smooth transition between the first groove wall segment 114 and the second groove wall segment 115. After the pressure relief part 112 is stressed, it is more conducive to reducing the risk of stress concentration on the bottom wall of the notch groove 113, can further improve the anti-deformation ability of the notch groove 113, and further reduce the risk of cracking of the pressure relief part 112.

[0148] According to some embodiments of the present application, in the direction from the first groove wall segment 114 to the second groove wall segment 115, the thickness of the third groove wall segment 116 gradually increases.

[0149] Among them, along the length direction of the notch groove 113, in the direction from the first groove wall segment 114 to the second groove wall segment 115, the thickness dimension of the third groove wall segment 116 gradually increases. Since the thickness dimension of the second groove wall segment 115 is greater than that of the first groove wall segment 114, by gradually increasing the thickness dimension of the third groove wall segment 116 in the direction from the first groove wall segment 114 to the second groove wall segment 115, a thickness-gradual change structure can be formed for the groove wall between the first groove wall segment 114 and the second groove wall segment 115, enabling a smooth and gentle transition between the first groove wall segment 114 and the second groove wall segment 115. After the pressure relief part 112 is stressed, it is more conducive to reducing the risk of stress concentration on the bottom wall of the notch groove 113, can further improve the anti-deformation ability of the notch groove 113, and further reduce the risk of cracking of the pressure relief part 112.

[0150] In the above technical solution, by gradually increasing the thickness dimension of the third groove wall segment 116 in the direction from the first groove wall segment 114 to the second groove wall segment 115, a thickness-gradual change structure can be formed for the groove wall between the first groove wall segment 114 and the second groove wall segment 115, enabling a smooth and gentle transition between the first groove wall segment 114 and the second groove wall segment 115. After the pressure relief part 112 is stressed, it is more conducive to reducing the risk of stress concentration on the bottom wall of the notch groove 113, can further improve the anti-deformation ability of the notch groove 113, and further reduce the risk of cracking of the pressure relief part 112.

[0151] According to some embodiments of the present application, as Figure 7 shown, the second groove wall segment 115 is arc-shaped, and along the first direction, the second groove wall segment 115 protrudes towards the outside of the housing body 111.

[0152] Among them, as Figure 7 shown, the second groove wall segment 115 can be set to an arc shape, and along the first direction, the second groove wall segment 115 protrudes towards the outside of the housing body 111, that is, along Figure 7 the Z direction in the second groove wall segment 115 protrudes towards the outside of the housing body 111. By making the second groove wall segment 115 protrude towards the outside of the housing body 111 along the first direction, the notch groove 113 can be configured into a wavy structure, which can simplify the structural shape of the notch groove 113, facilitate the formation of the notch groove 113 on the pressure relief portion 112, improve the production efficiency of the pressure relief portion 112, and thus improve the production efficiency of the battery cell 200.

[0153] In the above technical solution, by making the second groove wall segment 115 protrude towards the outside of the housing body 111 along the first direction, the notch groove 113 can be configured into a wavy structure, which can simplify the structural shape of the notch groove 113, facilitate the formation of the notch groove 113 on the pressure relief portion 112, improve the production efficiency of the pressure relief portion 112, and thus improve the production efficiency of the battery cell 200.

[0154] According to some embodiments of the present application, as Figure 7 shown, the second groove wall segment 115 is circular arc-shaped, and the radius of the second groove wall segment 115 is greater than or equal to 1 mm and less than or equal to 10 mm.

[0155] Among them, the second groove wall segment 115 can be set to a circular arc-shaped structure, the radius of the second groove wall segment 115 is greater than or equal to 1 mm and less than or equal to 10 mm, and the radius of the second groove wall segment 115 can be set to values such as 1 mm, 2 mm, 2.5 mm, 5 mm, 9 mm, 10 mm, etc. By setting the second groove wall segment 115 to a circular arc-shaped structure, a smooth transition can be formed at the bending portion of the notch groove 113. When the pressure relief portion 112 is stressed, the risk of stress concentration at the second groove wall segment 115 can be reduced, which is more conducive to reducing the risk of stress concentration at the bottom wall of the notch groove 113, can further improve the anti-deformation ability of the notch groove 113, and further reduce the risk of cracking of the pressure relief portion 112.

[0156] In the above technical solution, by setting the second groove wall section 115 as an arc-shaped structure, a smooth transition can be formed at the bending part of the notch groove 113. When the pressure relief part 112 is stressed, the risk of stress concentration generated at the second groove wall section 115 can be reduced, which is more conducive to reducing the risk of stress concentration generated at the bottom wall of the notch groove 113, further improving the anti-deformation ability of the notch groove 113, and further reducing the risk of cracking of the pressure relief part 112.

[0157] According to some embodiments of the present application, the second groove wall section 115 is a straight-line structure, and the second groove wall section 115 extends along the second direction.

[0158] Among them, the second groove wall section 115 can be set as a straight-line structure. It should be noted that the second groove wall section 115 is a straight-line structure, or the second groove wall section 115 is similar to a straight-line structure, and the second groove wall section 115 extends along the second direction. By setting the second groove wall section 115 as a straight-line structure, the structural shape of the notch groove 113 can be further simplified, the processing difficulty of the notch groove 113 can be reduced, it is more convenient to process the notch groove 113 on the pressure relief part 112, the production efficiency of the pressure relief part 112 can be further improved, and thus the production efficiency of the battery cell 200 can be further improved.

[0159] In the above technical solution, by setting the second groove wall section 115 as a straight-line structure, the structural shape of the notch groove 113 can be further simplified, the processing difficulty of the notch groove 113 can be reduced, it is more convenient to process the notch groove 113 on the pressure relief part 112, the production efficiency of the pressure relief part 112 can be further improved, and thus the production efficiency of the battery cell 200 can be further improved.

[0160] According to some embodiments of the present application, the ratio of the maximum thickness of the second groove wall section 115 to the minimum thickness of the first groove wall section 114 is greater than or equal to 1.1 and less than or equal to 1.8.

[0161] Among them, along the length direction of the notch groove 113, the thickness dimension of the second groove wall section 115 can remain unchanged, or the thickness dimension of the second groove wall section 115 can gradually change, the thickness dimension of the first groove wall section 114 can remain unchanged, or the thickness dimension of the first groove wall section 114 can gradually change. The ratio of the maximum thickness of the second groove wall section 115 to the minimum thickness of the first groove wall section 114 can be values such as 1.1, 1.2, 1.3, 1.5, 1.8, etc. For example Figure 7As shown, since the second groove wall section 115 is perpendicular or substantially perpendicular to the first direction, when the electrode assembly 300 expands, the flat area 301 of the electrode assembly 300 abuts against the second wall portion 12 and pushes the outer shell 60 outwards. The deformation of the second wall portion 12 will pull the first wall portion 11 along the first direction. And since the second groove wall section 115 is perpendicular or substantially perpendicular to the first direction, compared with the force on the first groove wall section 114, the force on the second groove wall section 115 will be greater than the force on the first groove wall section 114. Therefore, by making the ratio of the maximum thickness of the second groove wall section 115 to the minimum thickness of the first groove wall section 114 greater than or equal to 1.1 and less than or equal to 1.8, the structural strength at the second groove wall section 115 is not less than the structural strength at the first groove wall section 114, which can enable the second groove wall section 115 to meet the structural strength requirements, is more conducive to improving the overall structural strength of the notch groove 113, can further enhance the anti-deformation ability of the notch groove 113, and further reduce the cracking risk of the pressure relief portion 112.

[0162] In the above technical solution, by making the ratio of the maximum thickness of the second groove wall section 115 to the minimum thickness of the first groove wall section 114 greater than or equal to 1.1 and less than or equal to 1.8, the structural strength at the second groove wall section 115 is not less than the structural strength at the first groove wall section 114, which can enable the second groove wall section 115 to meet the structural strength requirements, is more conducive to improving the overall structural strength of the notch groove 113, can further enhance the anti-deformation ability of the notch groove 113, and further reduce the cracking risk of the pressure relief portion 112.

[0163] According to some embodiments of the present application, the ratio of the maximum thickness of the second groove wall section 115 to the maximum thickness of the shell body 111 is greater than or equal to 0.05 and less than or equal to 0.5.

[0164] Among them, the ratio of the maximum thickness of the second groove wall section 115 to the maximum thickness of the shell body 111 is greater than or equal to 0.05 and less than or equal to 0.5. The ratio of the maximum thickness of the second groove wall section 115 to the maximum thickness of the shell body 111 can be values such as 0.05, 0.1, 0.2, 0.15, 0.3, 0.4, 0.5, etc. By making the ratio of the maximum thickness of the second groove wall section 115 to the maximum thickness of the shell body 111 greater than or equal to 0.05 and less than or equal to 0.5, when the battery cell 200 undergoes thermal runaway, the pressure relief portion 112 can crack at the second groove wall section 115 and the first groove wall section 114, achieving a pressure relief effect and reducing the explosion risk of the battery cell 200.

[0165] In the above technical solution, by making the ratio of the maximum thickness of the second groove wall section 115 to the maximum thickness of the shell body 111 greater than or equal to 0.05 and less than or equal to 0.5, when the battery cell 200 undergoes thermal runaway, the pressure relief portion 112 can crack at the second groove wall section 115 and the first groove wall section 114, achieving a pressure relief effect and reducing the explosion risk of the battery cell 200.

[0166] According to some embodiments of the present application, as Figure 7 shown, two reinforcing ribs 117 are formed on the housing body 111, and both ends of the scoring groove 113 are respectively connected to the two reinforcing ribs 117.

[0167] Among them, the reinforcing ribs 117 can be integrally formed with the housing body 111. The scoring groove 113 can be located between the two reinforcing ribs 117. One end of the scoring groove 113 is connected to one reinforcing rib 117, and the other end of the scoring groove 113 is connected to the other reinforcing rib 117. By connecting both ends of the scoring groove 113 to the two reinforcing ribs 117 respectively, the reinforcing ribs 117 play a role in structural strengthening. When the bottom wall of the scoring groove 113 in the pressure relief portion 112 cracks and relieves pressure, the risk of continuously tearing the housing body 111 towards both ends of the scoring groove 113 can be reduced.

[0168] In the above technical solution, by connecting both ends of the scoring groove 113 to the two reinforcing ribs 117 respectively, the reinforcing ribs 117 play a role in structural strengthening. When the bottom wall of the scoring groove 113 in the pressure relief portion 112 cracks and relieves pressure, the risk of continuously tearing the housing body 111 towards both ends of the scoring groove 113 can be reduced.

[0169] According to some embodiments of the present application, as Figure 7 shown, the two reinforcing ribs 117 are opposite and spaced apart, and the reinforcing ribs 117 are arc-shaped.

[0170] Among them, the two reinforcing ribs 117 are arranged opposite and spaced apart along the second direction. The scoring groove 113 is located between the two reinforcing ribs 117. Each reinforcing rib 117 is arc-shaped, and the reinforcing rib 117 can be a circular arc structure. By setting the reinforcing rib 117 as a circular arc structure, the structural strength of the reinforcing rib 117 can be improved. When the bottom wall of the scoring groove 113 in the pressure relief portion 112 cracks and relieves pressure, the risk of continuously tearing the housing body 111 towards both ends of the scoring groove 113 can be further reduced.

[0171] In the above technical solution, by setting the reinforcing rib 117 as a circular arc structure, the structural strength of the reinforcing rib 117 can be improved. When the bottom wall of the scoring groove 113 in the pressure relief portion 112 cracks and relieves pressure, the risk of continuously tearing the housing body 111 towards both ends of the scoring groove 113 can be further reduced.

[0172] According to some embodiments of the present application, as Figure 7 shown, along the first direction, the pressure relief portion 112 is located at the middle position of the housing body 111.

[0173] Among them, along the first direction, the pressure relief part 112 is located at the middle position of the shell body 111. The pressure relief part 112 can be located at the exact center position of the shell body 111, and the notch groove 113 can be a wavy structure. It should be noted that the pressure relief part 112 deviating 5% of the width dimension of the shell body 111 along the first direction can be considered that the pressure relief part 112 is located at the middle position of the shell body 111. By the pressure relief part 112 being located at the middle position of the shell body 111 along the first direction, the force on each position of the notch groove 113 can be made uniform, the force on the notch groove 113 can be reduced, which is beneficial to tearing of each position of the notch groove 113 under the same bursting pressure, and further increases the fatigue life of the pressure relief part 112.

[0174] In the above technical solution, by the pressure relief part 112 being located at the middle position of the shell body 111 along the first direction, the force on each position of the notch groove 113 can be made uniform, the force on the notch groove 113 can be reduced, which is beneficial to tearing of each position of the notch groove 113 under the same bursting pressure, and further increases the fatigue life of the pressure relief part 112.

[0175] According to some embodiments of the present application, as Figure 4 shown, the shell body 111 has a shell bottom wall 118 opposite to the open end 120 of the outer shell 60, and the pressure relief part 112 is provided on the shell bottom wall 118.

[0176] Among them, the shell bottom wall 118 is used to support the electrode assembly 300 and is located below the electrode assembly 300. The first wall part 11 is connected between the two second wall parts 12 to define an installation cavity 30 with one end open. The shell body 111 has a shell bottom wall 118, and the shell bottom wall 118 is arranged opposite to the open end 120 of the installation cavity 30. The end cover 20 is used to close the open end 120 of the installation cavity 30. The shell bottom wall 118 is adjacently arranged with the second wall part 12, and the area of the shell bottom wall 118 is smaller than the area of the second wall part 12.

[0177] In the above technical solution, by arranging the pressure relief part 112 on the shell bottom wall 118, the effect of the battery cell 200 discharging pressure towards the bottom can be achieved, and the risk of high-temperature and high-pressure substances ejected from the battery cell 200 harming the surrounding personnel can be reduced.

[0178] According to some embodiments of the present application, as Figure 6 shown, the shell body 111 has a shell side wall 119 adjacent to the open end 120 of the outer shell 60, and the pressure relief part 112 is provided on the shell side wall 119.

[0179] Wherein, the first wall portion 11 is connected between two second wall portions 12 to define an installation cavity 30 with one end open, and the end cover 20 is used to close the open end 120 of the installation cavity 30. The housing body 111 has a housing side wall 119 adjacent to the end cover 20. It can also be understood that the housing side wall 119 is adjacent to the open end 120 of the installation cavity 30, and the housing side wall 119 is also adjacent to the second wall portion 12. The pressure relief portion 112 is provided on the housing side wall 119.

[0180] In the above technical solution, by providing the pressure relief portion 112 on the housing side wall 119, the effect of the battery cell 200 discharging pressure laterally can be achieved. During the pressure relief process of the battery cell 200, high-temperature and high-pressure substances inside the battery cell 200 can be quickly discharged from the battery cell 200.

[0181] According to some embodiments of the present application, the present application also provides a battery 400, including the battery cell 200 in the above embodiments.

[0182] According to some embodiments of the present application, the present application also provides an electrical device 500, including the battery 400 in the above embodiments.

[0183] According to some embodiments of the present application, referring to Figure 4 and Figure 7 As shown, the present application provides a battery cell 200, which includes an end cover 20, a housing 60, and an electrode assembly 300. The housing 60 defines an installation cavity 30, the electrode assembly 300 is installed in the installation cavity 30, and the end cover 20 closes the open end 120 of the installation cavity 30 and is fixedly connected to the housing 60. The housing 6 includes a first wall portion 11 and two second wall portions 12. The two second wall portions 12 are respectively located on both sides of the flat region 301 of the electrode assembly 300 along a first direction, and the second wall portion 12 is opposite to the flat region 301 of the electrode assembly 300. The pressure relief portion 112 is provided on the bottom wall 118 of the housing body 111, and the pressure relief portion 112 is formed with a scoring groove 113. The bottom wall of the scoring groove 113 has a first groove wall section 114 extending obliquely along the first direction, and the first groove wall section 114 forms an angle with the first direction. The scoring groove 113 can be a wavy structure.

[0184] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0185] As Figure 4 and Figure 6 As shown, the difference between the battery cell 200 of the first embodiment and the battery cell 200 of the second embodiment is that the pressure relief portion 112 of the battery cell 200 of the first embodiment is provided on the bottom wall 118, and the pressure relief portion 112 of the battery cell 200 of the second embodiment is provided on the housing side wall 119.

[0186] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0187] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A battery cell, characterized in that, comprising: An electrode assembly including a positive electrode tab and a negative electrode tab. After the positive electrode tab and the negative electrode tab are stacked, a flat area is formed. At least a part of the positive electrode tab and at least a part of the negative electrode tab are stacked in the flat area along a first direction; A housing for accommodating the electrode assembly. The housing includes a first wall portion and two second wall portions connected to the first wall portion. The two second wall portions are respectively located on both sides of the flat area along the first direction; Wherein, the first wall portion includes a shell body and a pressure relief portion. The shell body is disposed around the outer periphery of the pressure relief portion. The pressure relief portion is formed with a notch groove. The bottom wall of the notch groove has a first groove wall segment that extends obliquely along the first direction. The first groove wall segment forms an angle with the first direction.

2. The battery cell according to claim 1, characterized in that, The angle between the first groove wall segment and the first direction is greater than or equal to 20° and less than or equal to 70°.

3. The battery cell according to claim 1, characterized in that, The first groove wall segment is in multiple segments, and the multiple first groove wall segments are arranged in sequence along a second direction perpendicular to the first direction.

4. The battery cell according to claim 3, characterized in that, The bottom wall of the notch groove further has a second groove wall segment, and the second groove wall segment is connected between adjacent two first groove wall segments.

5. The battery cell according to claim 4, characterized in that, The thickness of the second groove wall segment is greater than the thickness of the first groove wall segment.

6. The battery cell according to claim 5, characterized in that, The bottom wall of the notch groove further has an arc-shaped third groove wall segment, and the third groove wall segment is connected between the adjacent first groove wall segment and the second groove wall segment.

7. The battery cell according to claim 6, characterized in that, The third groove wall segment is a circular arc structure.

8. The battery cell according to claim 6, characterized in that, From the direction of the first groove wall segment to the second groove wall segment, the thickness of the third groove wall segment gradually increases.

9. The battery cell according to any one of claims 4-8, characterized in that, The second groove wall segment is arc-shaped, and along the first direction, the second groove wall segment protrudes towards the outside of the shell body.

10. The battery cell according to claim 9, characterized in that, The second groove wall segment is circular arc-shaped, and the radius of the second groove wall segment is greater than or equal to 1 mm and less than or equal to 10 mm.

11. The battery cell according to any one of claims 4-8, characterized in that, The second groove wall segment is a linear structure, and the second groove wall segment extends along the second direction.

12. The battery cell according to any one of claims 5-8, characterized in that, The ratio of the maximum thickness of the second groove wall segment to the minimum thickness of the first groove wall segment is greater than or equal to 1.1 and less than or equal to 1.

8.

13. The battery cell according to any one of claims 4-8, characterized in that, The ratio of the maximum thickness of the second groove wall segment to the maximum thickness of the shell body is greater than or equal to 0.05 and less than or equal to 0.

5.

14. The battery cell according to any one of claims 1-8, characterized in that, two reinforcing ribs are formed on the shell body, and two ends of the notch groove are respectively connected to the two reinforcing ribs.

15. The battery cell according to claim 14, characterized in that, the two reinforcing ribs are opposite and spaced apart, and the reinforcing ribs are arc-shaped.

16. The battery cell according to any one of claims 1-8, characterized in that, along the first direction, the pressure relief portion is located at the middle position of the shell body.

17. The battery cell according to any one of claims 1-8, characterized in that, the shell body has a shell bottom wall opposite to the open end of the outer shell, and the pressure relief portion is arranged on the shell bottom wall.

18. The battery cell according to any one of claims 1-8, characterized in that, the shell body has a shell side wall adjacent to the open end of the outer shell, and the pressure relief portion is arranged on the shell side wall.

19. A battery, characterized in that, comprises the battery cell according to any one of claims 1-18.

20. An electrical device, characterized in that, comprises the battery according to claim 19.

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