Battery cell, battery, and electrical apparatus

Abstract

A battery cell (10), a battery (100), and an electrical apparatus. The battery cell (10) comprises a housing (11), a top cover (12), and an electrode assembly. The housing (11) is provided with an accommodating space (11a) and an opening (11b). The top cover (12) seals and covers the opening (11b). The electrode assembly is arranged within the accommodating space (11a). The top cover (12) is provided with a cover body (121) and a connecting side wall (122), one end of the connecting side wall (122) is connected to the side of the cover body (121) facing the electrode assembly, and the other end extends in the direction away from the cover body (121). The housing (11) is connected to an outer side wall of the connecting side wall (122), at least part of the area of the connecting side wall (122) located between the cover body (121) and the housing (11) is recessed to form a groove (122a), and the wall thickness of the connecting side wall (122) at the groove (122a) is not greater than the thickness of the connection between the housing (11) and the connecting side wall (122). The described structure reduces the risk of cracking of the connecting structure between the housing (11) and the top cover (12), solves the problem of failure of the connecting structure between the housing (11) and the top cover (12), and increases the service life of the battery cell (10).

Description

Battery monomer, battery and electric device

[0001] Cross-reference to related applications

[0002] The present disclosure is based on and claims priority to Chinese Patent Application No. 202420748798.7, filed on April 11, 2024, entitled "Battery monomer, battery and electric device", the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of batteries, and in particular to a battery monomer, a battery and an electric device. BACKGROUND

[0004] This section is intended to provide background or context to the embodiments of the present disclosure. The description herein is not admitted to be prior art merely by inclusion in this section.

[0005] In the production process of the battery, after the bare battery cell is put into the shell and the top cover is closed, a battery cell with a shell can be obtained. After the bare battery cell is put into the shell, shell cover welding needs to be performed to weld the shell and the top cover together. In the related art, when the bare battery cell circulates and expands and gas is generated during charging and discharging, the shell and the top cover connection part will crack, and there is a problem of causing the connection structure between the shell and the top cover to fail.

[0006] SUMMARY

[0007] Therefore, the embodiments of the present disclosure aim to provide a battery monomer, a battery and an electric device, which can improve the problem of failure of the connection structure between the shell and the top cover, and improve the service life of the battery monomer.

[0008] To achieve the above-mentioned purpose, a first aspect of the embodiments of the present disclosure provides a battery monomer, comprising:

[0009] a shell having a containing space and an opening;

[0010] a top cover, a sealing cover is arranged at the opening;

[0011] an electrode assembly arranged in the containing space;

[0012] The top cover is provided with a cover body and a connecting side wall, one end of the connecting side wall is connected to the side of the cover body facing the electrode assembly, the other end extends away from the cover body, and the shell is connected to the connecting side wall. At least part of the connecting side wall between the cover body and the shell is recessed to form a groove, and the wall thickness of the connecting side wall at the groove is not greater than the thickness of the connecting part of the shell and the connecting side wall.

[0013] The battery cell provided by the embodiments of the present disclosure has the following advantages. The top cover is provided with a cover body and a connecting side wall, and the shell is connected with the connecting side wall. This structure can improve the deformation capacity of the top cover, and is conducive to increasing the contact area and the connecting area of the top cover and the shell, improving the shear resistance (also referred to as shear strength) of the connecting position of the shell and the top cover, that is, improving the maximum stress value that the connecting position of the shell and the top cover can bear under the action of shear force, thereby improving the structural strength of the connecting position of the shell and the top cover. In addition, the connecting side wall is recessed to form a groove in at least a partial region between the cover body and the shell. The wall thickness of the connecting side wall at the groove is not greater than the thickness of the connecting position of the shell and the connecting side wall. Therefore, when the connecting position of the shell and the top cover is subjected to force due to the cyclic expansion of the electrode assembly and the generation of gas during charging and discharging, the force is more likely to act on the groove, that is, the groove in the connecting side wall forms a stress buffer zone of the connecting position of the shell and the top cover, thereby reducing the stress of the connecting structure between the shell and the top cover and reducing the risk of cracking of the connecting structure between the shell and the top cover, improving the failure problem of the connecting structure between the shell and the top cover, and improving the service life of the battery cell.

[0014] In some embodiments, the inner side wall of the connecting side wall is recessed to form the groove.

[0015] In this embodiment, the groove is formed in the inner side wall of the connecting side wall, which is conducive to improving the aesthetics of the battery cell and can also avoid the deposition of dust and other foreign matters in the groove.

[0016] In some embodiments, the groove is formed at the connecting position of the connecting side wall and the cover body.

[0017] In this embodiment, the groove is arranged at the connecting position of the connecting side wall and the cover body, away from the end of the connecting side wall connected with the shell. Therefore, when the connecting position between the shell and the top cover is subjected to force, the moment of force of the connecting side wall at the groove can be increased, which is further conducive to concentrating the deformation at the position of the connecting side wall at the groove, thereby further reducing the risk of fatigue cracking of the connecting structure between the shell and the top cover.

[0018] In some embodiments, the groove extends along the edge of the top cover.

[0019] The distance between any two positions of the groove in the extension direction of the groove and the edge of the top cover can be the same, that is, the distance between any two positions of the groove in the extension direction of the groove and the outer side wall of the connecting side wall can be the same. Therefore, the stress near the groove can be more uniform.

[0020] In some embodiments, in a cross section perpendicular to the extension direction of the groove, the size of the groove in the height direction of the battery cell is H1, where 0.5 mm≤H1≤2 mm.

[0021] The connecting side wall can have sufficient strength, and stress at the connection between the shell and the top cover can be transmitted to the groove, which is conducive to concentrating deformation at the groove, thereby reducing stress of the connection structure between the shell and the top cover, reducing the risk of cracking of the connection structure between the shell and the top cover, and prolonging the service life of the top cover.

[0022] In some embodiments, in a cross section perpendicular to the extension direction of the groove, the size of the groove in the height direction of the battery cell is H1, where 0.5 mm≤H1≤1.5 mm.

[0023] The connecting side wall can have sufficient strength, and stress at the connection between the shell and the top cover can be transmitted to the groove, which is conducive to concentrating deformation at the groove, thereby reducing stress of the connection structure between the shell and the top cover, reducing the risk of cracking of the connection structure between the shell and the top cover, and prolonging the service life of the top cover.

[0024] In some embodiments, the connecting side wall includes a connecting body and a connecting region arranged at an end of the connecting body away from the cover body, the distance between the outer side wall of the connecting region and the central axis of the battery cell is less than the distance between the connecting body and the central axis of the battery cell, the connecting region extends into the shell, and the end surface of the shell is connected to the end surface of the connecting body.

[0025] In this embodiment, by setting the distance between the outer side wall of the connecting region and the central axis of the battery cell to be less than the distance between the connecting body and the central axis of the battery cell, the connecting region extends into the shell when assembled, and the end surface of the shell is connected to the end surface of the connecting body. In this way, when the shell deforms, the stress mode between the shell and the top cover in the related art is changed, and the connecting region is conducive to supporting the shell, thereby improving the strength of the connection structure between the shell and the top cover.

[0026] In some embodiments, the outer surface of the connecting body is flush with the outer surface of the cover body.

[0027] By setting the outer surface of the connecting body to be flush with the outer surface of the cover body, the appearance of the battery cell is improved, and deposition of dust and other foreign matter between the connecting body and the cover body is avoided, while the occupied space of the battery cell is reduced as much as possible, thereby improving the energy density of the battery.

[0028] In some embodiments, the outer surface of the connecting body is flush with the outer surface of the shell.

[0029] In this embodiment, by setting the outer surface of the connecting body to be flush with the outer surface of the shell, the appearance of the battery cell is improved, and deposition of dust and other foreign matter between the connecting body and the shell is avoided, while the occupied space of the battery cell is reduced as much as possible, thereby improving the energy density of the battery.

[0030] In some embodiments, the size of the connecting region in the height direction of the battery cell is H2, wherein 0.5mm≤H2≤4mm.

[0031] In this embodiment, by setting the size of the connecting region in the height direction of the battery cell to 0.5mm-4mm, the connecting structure of the shell and the top cover can have sufficient strength, and the occupied space of the battery cell can be small, and the energy density of the battery cell can be improved.

[0032] In some embodiments, the size of the connecting side wall in the height direction of the battery cell is H3, wherein 1.5mm≤H3≤8mm.

[0033] In this embodiment, by setting the size of the connecting side wall in the height direction of the battery cell to 1.5mm-8mm, the connecting structure of the shell and the top cover can have sufficient strength, and it is beneficial to concentrate the deformation at the groove, and the occupied space of the battery cell can be small, and the energy density of the battery cell can be improved.

[0034] In some embodiments, the thickness of the connecting part of the shell and the connecting side wall is L1, and the thickness of the connecting body is L2, wherein 1mm≤L2≤10L1.

[0035] The connecting body can have sufficient strength, so as to improve the structural strength of the connecting part of the shell and the top cover, and it is beneficial to transfer the stress of the connecting part of the shell and the top cover to the groove, so as to concentrate the deformation at the groove, and then reduce the stress of the connecting structure between the shell and the top cover, further reduce the risk of cracking of the connecting structure between the shell and the top cover, improve the failure problem of the connecting structure between the shell and the top cover, and improve the service life of the battery cell.

[0036] In some embodiments, the thickness of the connecting part of the shell and the connecting side wall is L1, and the thickness of the connecting body is L2, wherein 1mm≤L2≤4L1.

[0037] The connecting body can have sufficient strength, so as to improve the structural strength of the connecting part of the shell and the top cover, and it is beneficial to further transfer the stress of the connecting part of the shell and the top cover to the groove, so as to concentrate the deformation at the groove, and then reduce the stress of the connecting structure between the shell and the top cover, further reduce the risk of cracking of the connecting structure between the shell and the top cover, improve the failure problem of the connecting structure between the shell and the top cover, and improve the service life of the battery cell.

[0038] In some embodiments, the size of the cover body in the height direction of the shell is H4, wherein 1mm≤H4≤5mm; and / or, the thickness of the connecting part of the shell and the connecting side wall is L1, wherein 0.4mm≤L1≤2mm.

[0039] By setting the height of the cover body to 1mm-5mm, the top cover can have sufficient strength for protecting the electrode assembly in the accommodation space, while reducing the weight and volume of the battery monomer, reducing the material of the top cover, reducing the cost, and improving the comprehensive performance of the battery.

[0040] By setting the thickness of the connection between the shell and the connecting side wall to 0.4mm-2mm, the connection between the top cover and the shell has sufficient connection strength, while reducing the weight and volume of the battery monomer, reducing the material of the top cover, reducing the cost, and improving the comprehensive performance of the battery.

[0041] In some embodiments, the height of the cover body in the height direction of the shell is H4, where 1.5mm≤H4≤3mm; and / or the thickness of the connection between the shell and the connecting side wall is L1, where 0.6mm≤L1≤1.7mm.

[0042] By setting the height of the cover body to 1.5mm-3mm, the top cover can have sufficient strength for protecting the electrode assembly in the accommodation space, while further reducing the weight and volume of the battery monomer, reducing the material of the top cover, reducing the cost, and further improving the comprehensive performance of the battery.

[0043] By setting the thickness of the connection between the shell and the connecting side wall to 0.6mm-1.7mm, the connection between the top cover and the shell has sufficient connection strength, while further reducing the weight and volume of the battery monomer, reducing the material of the top cover, reducing the cost, and further improving the comprehensive performance of the battery.

[0044] The second aspect of the embodiments of the present disclosure provides a battery comprising at least one battery monomer as described above.

[0045] The battery provided by the embodiments of the present disclosure comprises at least one battery cell of the embodiments of the present disclosure, the top cover is provided with a cover body and a connecting side wall, and the shell is connected with the connecting side wall. This structure can improve the deformation ability of the top cover, and is conducive to increasing the contact area and the connecting area of the top cover and the shell, improving the shear resistance (also referred to as shear strength) of the connecting position of the shell and the top cover, that is, improving the maximum stress value that can be borne by the connecting position of the shell and the top cover under the action of shear force, thereby improving the structural strength of the connecting position of the shell and the top cover. In addition, at least part of the area between the cover body and the shell is recessed to form a groove, and the wall thickness of the connecting side wall at the groove is not greater than the thickness of the connecting position of the shell and the connecting side wall. Therefore, when the electrode assembly cyclically expands and generates gas during charging and discharging, the force acting on the connecting position of the shell and the top cover is more likely to act on the groove, that is, the groove on the connecting side wall forms a stress buffer zone of the connecting position of the shell and the top cover, thereby reducing the stress of the connecting structure between the shell and the top cover, reducing the risk of cracking of the connecting structure between the shell and the top cover, improving the failure problem of the connecting structure between the shell and the top cover, and improving the service life of the battery cell.

[0046] The third aspect of the embodiments of the present disclosure provides a power utilization device comprising the battery described above, and the battery is used to provide electric energy for the power utilization device.

[0047] The power utilization device provided by the embodiments of the present disclosure comprises a battery, and the battery comprises at least one battery cell of the embodiments of the present disclosure. The top cover is provided with a cover body and a connecting side wall, and the shell is connected with the connecting side wall. This structure can improve the deformation ability of the top cover, and is conducive to increasing the contact area and the connecting area of the top cover and the shell, improving the shear resistance (also referred to as shear strength) of the connecting position of the shell and the top cover, that is, improving the maximum stress value that can be borne by the connecting position of the shell and the top cover under the action of shear force, thereby improving the structural strength of the connecting position of the shell and the top cover. In addition, at least part of the area between the cover body and the shell is recessed to form a groove, and the wall thickness of the connecting side wall at the groove is not greater than the thickness of the connecting position of the shell and the connecting side wall. Therefore, when the electrode assembly cyclically expands and generates gas during charging and discharging, the force acting on the connecting position of the shell and the top cover is more likely to act on the groove, that is, the groove on the connecting side wall forms a stress buffer zone of the connecting position of the shell and the top cover, thereby reducing the stress of the connecting structure between the shell and the top cover, reducing the risk of cracking of the connecting structure between the shell and the top cover, improving the failure problem of the connecting structure between the shell and the top cover, and improving the service life of the battery cell. BRIEF DESCRIPTION OF DRAWINGS

[0048] FIG. 1 is a structural schematic diagram of a vehicle provided by an embodiment of the present disclosure;

[0049] FIG. 2 is a perspective exploded schematic diagram of a battery provided by an embodiment of the present disclosure;

[0050] FIG. 3 is a top view of a battery cell according to an embodiment of the present disclosure;

[0051] FIG. 4 is a cross-sectional view of FIG. 3 in the A-A direction;

[0052] FIG. 5 is an enlarged view of B in FIG. 4;

[0053] FIG. 6 is a deformation schematic view of a connection between a housing and a top cover when a force is applied according to an embodiment of the present disclosure;

[0054] FIG. 7 is a cracking schematic view of a connection between a housing and a top cover according to the prior art.

[0055] Reference Signs 10: battery cell; 11: housing; 11a: accommodation space; 11b: opening; 12: top cover; 121: cover body; 122: connection side wall; 122a: groove; 122b: connection body; 122c: connection area; 20: battery box; 21: first box body part; 22: second box body part; 100: battery; 200: controller; 300: motor; 1000: vehicle. DETAILED DESCRIPTION

[0056] It should be noted that the embodiments and technical features in the present disclosure can be combined with each other without conflict, and the detailed description in the specific embodiments should be understood as an explanation of the purpose of the present disclosure, and should not be regarded as an improper limitation of the present disclosure.

[0057] 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 present disclosure belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure; the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion.

[0058] In the description of the embodiments of the present disclosure, the technical terms "first", "second", "third", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0059] 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 present disclosure. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0060] In the description of the embodiments of the present disclosure, the term "and / or" is merely an association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A existing alone, A and B existing together, and B existing alone. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects.

[0061] In the description of the embodiments of the present disclosure, the orientations or positional relationships indicated by the technical terms "length", "width", "thickness", "height", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "circumferential", "height direction", "first direction", "second direction" and the like are based on the orientations or positional relationships shown in the drawings, and are merely for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed, operated or used in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present disclosure.

[0062] In the description of the embodiments of the present disclosure, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or can be integrated; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0063] In the description of the embodiments of the present disclosure, unless otherwise explicitly specified and limited, the technical term "contact" should be understood in a broad sense, which can be direct contact or contact through an intermediate medium layer, and can be contact between two objects in contact without interaction force, or contact between two objects in contact with interaction force.

[0064] With the development of clean energy, more and more equipment uses electric energy as driving energy, and then as power battery which can store more electric energy and can be charged and discharged repeatedly, such as lithium ion battery. Among them, the power battery is not only applied to energy storage power supply systems such as hydroelectric, thermal, wind and solar power stations, but also widely used in electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, as well as aerospace and other fields.

[0065] In the present disclosure, the battery cell can include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-ion battery, a sodium-ion battery, or a magnesium-ion battery, etc., and the present disclosure embodiments are not limited thereto. The battery cell can be in the shape of a cylinder, a cuboid, or other shapes, etc., and the present disclosure embodiments are not limited thereto.

[0066] The battery referred to in the embodiments of the present disclosure refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in the present disclosure can include a battery module or a battery pack, etc. The battery generally includes a case for packaging one or more battery cells. The case can prevent liquids or other foreign matters from affecting the charging or discharging of the battery cell.

[0067] The battery cell includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive electrode tab, a negative electrode tab, and a separator. The battery cell mainly works by moving metal ions between the positive electrode tab and the negative electrode tab. The positive electrode tab includes a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode current collector. The positive electrode current collector, which is not coated with the positive electrode active material layer, protrudes from the positive electrode current collector, which is coated with the positive electrode active material layer, and serves as a positive electrode tab. Taking a lithium-ion battery as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate, etc. The negative electrode tab includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode current collector. The negative electrode current collector, which is not coated with the negative electrode active material layer, protrudes from the negative electrode current collector, which is coated with the negative electrode active material layer, and serves as a negative electrode tab. The material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon, etc. In order to ensure that no fusing occurs when passing a large current, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together. The material of the separator can be PP (polypropylene) or PE (polyethylene), etc.

[0068] Exemplarily, the positive electrode current collector has two opposite surfaces in the thickness direction thereof, and the positive electrode active material is disposed on either one or both of the two opposite surfaces of the positive electrode current collector.

[0069] Exemplarily, the positive electrode current collector can employ a metal foil or a composite current collector. For example, as the metal foil, silver-plated aluminum, silver-plated stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, etc. can be employed. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material base material (e.g., a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0070] Exemplarily, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative electrode current collector.

[0071] Exemplarily, the negative electrode current collector can employ a metal foil or a composite current collector. For example, as the metal foil, silver-plated aluminum, silver-plated stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, etc. can be employed.

[0072] Exemplarily, the negative electrode current collector has two surfaces opposite in the thickness direction thereof, and the negative electrode active material is disposed on either one or both of the two surfaces of the negative electrode current collector.

[0073] Exemplarily, the negative electrode active material can employ a negative electrode active material for a battery known in the art. As an example, the negative electrode active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, lithium titanate, etc. The silicon-based material can be selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can be selected from at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present disclosure is not limited to these materials, and other conventional materials that can be used as a battery negative electrode active material can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0074] The battery cell further includes a packaging film and a case. The packaging film is coated on the outside of the electrode assembly, and the case encapsulates the electrode assembly coated with the packaging film, thereby forming the battery cell. The packaging film can be a mylar film, and the case can be an aluminum case. The mylar film and the case are encapsulated after the electrode assembly is wound into a shape, through a mylar coating process and a case insertion process. The mylar film serves to seal and protect the electrode assembly, and the mylar film can effectively insulate the electrode assembly and the case from each other, thereby preventing internal short circuit of the battery cell. The case serves to protect.

[0075] Exemplarily, the shell comprises a top cover and a shell body, the shell is provided with an opening, and the top cover seals the opening to form a sealed space for accommodating the electrode assembly, the electrolyte and other substances. The shell can be provided with one or more openings. The top cover can also be provided with one or more openings.

[0076] Exemplarily, at least one electrode terminal is arranged on the shell, and the electrode terminal is electrically connected with the tab of the electrode assembly. The electrode terminal can be directly connected with the tab or indirectly connected with the tab through an adapter. The electrode terminal can be arranged on the top cover or arranged on the shell body.

[0077] Exemplarily, an explosion-proof valve is arranged on the shell. The explosion-proof valve is used to release the internal pressure of the battery monomer.

[0078] Exemplarily, the battery monomer can be a cylindrical battery monomer, a prismatic battery monomer, a soft package battery monomer or other shaped battery monomers, and the prismatic battery monomer includes a square battery monomer, a blade-shaped battery monomer, a multi-prismatic battery monomer, for example, a hexagonal battery monomer, and the like. The embodiments of the present disclosure are not particularly limited.

[0079] Exemplarily, the battery monomer further comprises a pressure relief structure, which can be arranged on the top cover or the shell body to release the internal pressure or temperature of the battery monomer.

[0080] The development of battery technology needs to consider various design factors, such as energy density, discharge capacity, charge-discharge rate and other performance parameters, and the reliability of the battery also needs to be considered.

[0081] In the related art, as shown in FIG. 7, when the electrode assembly generates gas during the process of cyclic expansion and charging and discharging, the force acting on the shell and the top cover causes the shell to deform outward, thereby stretching the connecting structure between the shell and the top cover, and further causing the connecting structure between the shell and the top cover to fatigue and crack, thereby causing the connecting structure between the shell and the top cover to fail.

[0082] In order to improve the problem of failure of the connecting structure between the shell and the top cover and improve the service life of the battery monomer, the embodiments of the present disclosure provide a battery monomer, which comprises a shell, a top cover and an electrode assembly. The shell has an accommodation space and an opening. The top cover sealing cover is arranged at the opening. The electrode assembly is arranged in the accommodation space. The top cover is provided with a cover body and a connecting side wall, one end of the connecting side wall is connected with the side of the cover body facing the electrode assembly, the other end extends away from the cover body, and the shell is connected with the outer side wall of the connecting side wall. At least part of the connecting side wall between the cover body and the shell is recessed to form a groove, and the wall thickness of the connecting side wall at the groove is not greater than the thickness of the connecting position of the shell and the connecting side wall.

[0083] The battery cell provided by the embodiments of the present disclosure can improve the deformation ability of the top cover, and can also improve the contact area and the connection area between the top cover and the shell, and can improve the shear resistance of the connection between the shell and the top cover, that is, the maximum stress value that can be borne by the connection between the shell and the top cover under the action of shear force, thereby improving the structural strength of the connection between the shell and the top cover. In addition, the connecting side wall is recessed to form a groove in at least part of the area between the cover body and the shell, and the wall thickness of the connecting side wall at the groove is not greater than the thickness of the connection between the shell and the connecting side wall. Therefore, when the electrode assembly cyclically expands and generates gas during charging and discharging, the force acting on the connection between the shell and the top cover is more likely to act on the groove, that is, the groove in the connecting side wall forms a stress buffer zone of the connection between the shell and the top cover, thereby reducing the stress of the connection structure between the shell and the top cover, reducing the risk of cracking of the connection structure between the shell and the top cover, improving the failure problem of the connection structure between the shell and the top cover, and improving the service life of the battery cell.

[0084] The technical solutions described in the embodiments of the present disclosure are suitable for batteries and electric devices using batteries.

[0085] The battery mentioned in the embodiments of the present disclosure refers to at least one battery cell provided by the embodiments of the present disclosure. One or more battery cells provide a single physical module with higher voltage and capacity. For example, the battery mentioned in the present disclosure can include a battery module or a battery pack, etc. The battery generally includes a box for packaging one or more battery cells. The box can prevent liquids or other foreign matter from affecting the charging or discharging of the battery cell.

[0086] 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 an extended range electric 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 console, 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 assembly 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 drill, a concrete vibrator, and an electric planer, etc. The embodiments of the present disclosure do not specially limit the above-mentioned electric devices.

[0087] It should be noted that the technical solutions described in the embodiments of the present disclosure are not only limited to the above-mentioned batteries and electric devices, but can also be applied to all batteries including a box and electric devices using batteries, but for the sake of simplicity, the following embodiments are described by taking an electric vehicle as an example.

[0088] Referring to FIG. 1, FIG. 1 is a structural schematic diagram of a vehicle 1000 according to some embodiments of the present disclosure. The vehicle 1000 can be internally provided with a controller 200, a motor 300, and a battery 100, and the controller 200 can be configured to control the battery 100 to supply power to the motor 300. For example, the battery 100 can be arranged at the bottom, the front, or the rear of the vehicle 1000. The battery 100 can be configured to supply power to the vehicle 1000, for example, the battery 100 can be configured as an operating power source of the vehicle 1000, and can be configured to supply power to the circuit system of the vehicle 1000, for example, to meet the power demand of the vehicle 1000 during starting, navigation, and operation. In another embodiment of the present disclosure, the battery 100 can be configured not only as an operating power source of the vehicle 1000, but also as a driving power source of the vehicle 1000, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 1000.

[0089] In order to meet different power demands, the battery 100 can include a plurality of battery cells 10, and the battery cell 10 can be the smallest unit of a battery 100 module or a battery 100 pack. The plurality of battery cells 10 can be connected in series, in parallel, or in a mixed connection, and the mixed connection means that the plurality of battery cells 10 are connected in series and in parallel. The plurality of battery cells 10 can be directly connected in series, in parallel, or in a mixed connection, and the plurality of battery cells 10 can be accommodated in a box. Of course, the battery 100 can be in the form of a plurality of battery cells 10 connected in series, in parallel, or in a mixed connection to form a battery 100 module, and a plurality of battery 100 modules can be connected in series, in parallel, or in a mixed connection to form a whole and can be accommodated in a box. The battery 100 can also include other structures, for example, the battery 100 can also include a busbar component for realizing electrical connection between the plurality of battery cells 10. Each battery cell 10 can be a secondary battery or a primary battery, and can be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 10 can be in the form of a cylinder, a flat body, a cuboid, or other shapes.

[0090] Referring to FIG. 2, the battery 100 includes a battery box 20 and at least one battery cell 10, and the battery cell 10 is arranged in the mounting space of the battery box 20.

[0091] The battery box 20 can be a simple cuboid or a cylinder or a sphere, or can be a complex cuboid structure composed of a simple cuboid or a cylinder or a sphere. The material of the battery box 20 can be an alloy material such as an aluminum alloy or an iron alloy, or a high polymer material such as polycarbonate or polyisocyanurate foam plastic, or a composite material such as glass fiber and epoxy resin.

[0092] The battery box 20 is used to accommodate the battery monomer 10, and the battery box 20 can be of various structures. In some embodiments, the battery box 20 can include a first box body part 21 and a second box body part 22, the first box body part 21 and the second box body part 22 are mutually covered, and the first box body part 21 and the second box body part 22 jointly define a mounting space for accommodating the battery monomer 10. The second box body part 22 can be a hollow structure with an open end 11b, and the first box body part 21 is a plate-shaped structure, which is covered on the open end 11b side of the second box body part 22 to form the battery box 20 with the mounting space; the first box body part 21 and the second box body part 22 can also be hollow structures with one side open, and the open end 11b side of the first box body part 21 is covered on the open side of the second box body part 22 to form the battery box 20 with the mounting space. Of course, the first box body part 21 and the second box body part 22 can be of various shapes, such as a cylinder, a cuboid, etc.

[0093] In order to improve the sealing performance of the first box body part 21 and the second box body part 22 after being connected, a sealing member such as sealing glue, a sealing ring, etc. can be arranged between the first box body part 21 and the second box body part 22.

[0094] Suppose that the first box body part 21 is covered on the top of the second box body part 22, the first box body part 21 can also be called an upper box cover, and the second box body part 22 can also be called a lower box cover.

[0095] In the battery 100, the battery monomer 10 can be one or multiple. If the battery monomer 10 is multiple, the multiple battery monomers 10 can be connected in series, in parallel or in a mixed manner, and the mixed manner means that the multiple battery monomers 10 are connected in series and in parallel. The multiple battery monomers 10 can be directly connected in series, in parallel or in a mixed manner, and then the whole of the multiple battery monomers 10 is accommodated in the battery box 20; of course, the multiple battery monomers 10 can be first connected in series, in parallel or in a mixed manner to form a battery 100 module, and then multiple battery 100 modules are connected in series, in parallel or in a mixed manner to form a whole, which is accommodated in the battery box 20.

[0096] Exemplarily, the battery monomer 10 can include a lithium ion battery monomer, a sodium ion battery monomer or a magnesium ion battery monomer, etc., and the embodiments of the present disclosure are not limited in this regard. The battery monomer 10 can be in the shape of a cylinder, a flat body, a cuboid or other shapes, etc., and the embodiments of the present disclosure are not limited in this regard. The battery monomer 10 is generally divided into three types according to the packaging manner: a cylindrical battery monomer 10, a square battery monomer 10 and a soft package battery monomer 10, and the embodiments of the present disclosure are not limited in this regard.

[0097] The battery cell provided by the embodiments of the present disclosure, please refer to FIG. 3 to FIG. 6, the battery cell 10 comprises a shell 11, a top cover 12 and an electrode assembly. The shell 11 has a containing space 11a and an opening 11b. The top cover 12 is sealed and covers the opening 11b. The electrode assembly is arranged in the containing space 11a. Wherein, the top cover 12 is provided with a cover body 121 and a connecting side wall 122, one end of the connecting side wall 122 is connected with the side of the cover body 121 facing the electrode assembly, the other end extends away from the cover body 121, and the outer side wall of the connecting side wall 122 is connected with the shell 11; at least part of the area between the cover body 121 and the connecting side wall 122 is recessed to form a groove 122a, and the wall thickness of the connecting side wall 122 at the groove 122a is not greater than the thickness of the connecting position of the connecting side wall 122 and the shell 11.

[0098] Here, the shell can be a cylinder, a flat body, a cuboid or other shapes, etc.

[0099] It should be noted that the height direction of the shell 11 in the embodiments of the present disclosure is the direction of entering the containing space 11a from the opening 11b, or the opposite direction of entering the containing space 11a from the opening 11b. When the shell 11 is in the shape of a cylinder, the height direction of the shell 11 is the axial direction of the shell 11.

[0100] It should be noted that the specific way of connecting the top cover 12 with the shell 11 is not limited here, for example, welding.

[0101] Exemplarily, the cover body 121 and the connecting side wall 122 are in an integrated structure. The integrated cover body 121 and the connecting side wall 122 can reduce the number of parts, reduce the assembly time, improve the assembly efficiency and the structural strength.

[0102] Of course, the cover body 121 and the connecting side wall 122 can also be in a split structure, for example, the connecting side wall 122 is welded on the side of the cover body 121 close to the electrode assembly. The split cover body 121 and the connecting side wall 122 are beneficial to forming.

[0103] Exemplarily, at least part of the connecting side wall 122 extends into the containing space 11a through the opening 11b, and then the outer side wall of the connecting side wall 122 is connected with the shell 11.

[0104] Here, the top cover 12 is provided with the cover body 121 and the connecting side wall 122. On the one hand, the outer side wall of the connecting side wall 122 is connected with the shell 11. When the connecting part between the shell 11 and the top cover 12 is subjected to force, a moment can be formed on the connecting side wall 122, so that the connecting side wall 122 or the cover body 121 can be deformed (see FIG. 7). That is, when the connecting part between the shell 11 and the top cover 12 is subjected to force during the cyclic expansion of the electrode assembly and the generation of gas during charging and discharging, the force is more easily transmitted to the top cover 12 to cause the connecting side wall 122 to deform. On the other hand, at least part of the connecting side wall 122 between the cover body 121 and the shell 11 is recessed to form a groove 122a. The wall thickness of the connecting side wall 122 at the groove 122a is not greater than the thickness of the connecting part between the shell 11 and the connecting side wall 122. This is advantageous for weakening the strength of the connecting side wall 122 at the groove 122a. Thus, when the connecting part between the shell 11 and the top cover 12 is subjected to force, the force is more easily applied to the groove 122a of the connecting side wall 122. That is, the position of the connecting side wall 122 at the groove 122a corresponds to a stress buffer zone of the connecting part between the shell 11 and the top cover 12.

[0105] The recessing of the connecting side wall 122 at least part of the connecting side wall 122 between the cover body 121 and the shell 11 to form the groove 122a means that at least part of the connecting side wall 122 in the height direction of the battery monomer 10 and between the cover body 121 and the shell 11 is recessed to form the groove 122a. This is equivalent to thinning part of the connecting side wall 122 to form the groove 122a, which can weaken the strength of the connecting side wall 122 at the groove 122a.

[0106] Here, the wall thickness L3 of the connecting side wall 122 at the groove 122a is not greater than the thickness L1 of the connecting part between the shell 11 and the connecting side wall 122. That is, the wall thickness of the connecting side wall 122 at the groove 122a is less than or equal to the thickness of the connecting part between the shell 11 and the connecting side wall 122. In this way, it is advantageous for the deformation to be concentrated at the groove 122a.

[0107] The top cover 12 is generally perpendicular to the side of the shell 11. When the shell 11 deforms outwardly, a shear force can be generated at the connecting part between the shell 11 and the top cover 12. When the shell 11 is subjected to force during the cyclic expansion of the electrode assembly and the generation of gas during charging and discharging, the deformation can be concentrated at the position of the connecting side wall 122 at the groove 122a. Thus, the shear force at the connecting part between the shell 11 and the top cover 12 is reduced, the risk of fatigue cracking of the connecting structure between the shell 11 and the top cover 12 is reduced, the problem of failure of the connecting structure between the shell 11 and the top cover 12 is improved, and the service life of the battery monomer 10 is improved.

[0108] The battery monomer 10 provided by the embodiments of the present disclosure has the following advantages. The top cover 12 is provided with the cover body 121 and the connecting side wall 122, and the shell 11 is connected with the connecting side wall 122. This structure can improve the deformation ability of the top cover 12, and is conducive to increasing the contact area and the connecting area of the top cover 12 and the shell 11, improving the shear resistance (also referred to as shear strength) of the connecting position of the shell 11 and the top cover 12, that is, improving the maximum stress value that the connecting position of the shell 11 and the top cover 12 can bear under the action of shear force, thereby improving the structural strength of the connecting position of the top cover 12 and the shell 11. In addition, the connecting side wall 122 is recessed to form the groove 122a in at least part of the area between the cover body 121 and the shell 11. The wall thickness of the connecting side wall 122 at the groove 122a is not greater than the thickness of the connecting position of the shell 11 and the connecting side wall 122. Therefore, when the electrode assembly cyclically expands and generates gas during charging and discharging, the force acting on the connecting position of the shell 11 and the top cover 12 is more likely to act on the groove 122a. That is, the groove 122a on the connecting side wall 122 forms a stress buffer zone of the connecting position of the shell 11 and the top cover 12, thereby reducing the stress of the connecting structure between the shell 11 and the top cover 12, reducing the risk of cracking of the connecting structure between the shell 11 and the top cover 12, improving the failure problem of the connecting structure between the shell 11 and the top cover 12, and improving the service life of the battery monomer 10.

[0109] It should be noted that the specific setting position of the groove 122a is not limited herein.

[0110] In some embodiments, referring to FIGS. 4 to 6, the inner side wall of the connecting side wall 122 is recessed to form the groove 122a. That is, the groove 122a is formed in the inner side wall of the connecting side wall 122.

[0111] In this embodiment, by forming the groove 122a in the inner side wall of the connecting side wall 122, the aesthetic appearance of the battery monomer 10 is improved, and the deposition of foreign matters such as dust in the groove 122a can also be avoided.

[0112] In other embodiments, the outer side wall of the connecting side wall 122 is recessed to form the groove 122a. That is, the groove 122a is formed in the outer side wall of the connecting side wall 122.

[0113] It can be understood that the groove 122a can be formed at any position between the shell 11 and the cover body 121.

[0114] In some embodiments, referring to FIG. 5, the groove 122a is formed at the connecting position of the connecting side wall 122 and the cover body 121.

[0115] That is, the groove 122a is formed at one end of the connecting side wall 122 connected with the cover body 121, and the connecting side wall 122 is connected with the cover body 121 through the area where the groove 122a is formed.

[0116] In this embodiment, by setting the groove 122a at the connection between the connecting side wall 122 and the cover body 121, away from the end where the connecting side wall 122 is connected to the shell 11, when the connection between the shell 11 and the top cover 12 is subjected to a force, the moment of force of the connecting side wall 122 at the groove 122a can be increased, and the deformation can be further concentrated at the position of the connecting side wall 122 at the groove 122a (see FIG. 6), thereby further reducing the risk of fatigue cracking of the connection structure between the shell 11 and the top cover 12.

[0117] In some embodiments, the groove 122a extends along the edge of the top cover 12.

[0118] Here, the groove 122a extends along the edge of the top cover 12, that is, the profile shape of the center line of the groove 122a in the extending direction is completely or approximately the same as the profile shape of the top cover 12 when projected on a plane parallel to the top cover 12.

[0119] It can be understood that, by extending the groove 122a along the edge of the top cover 12, the distance between any two positions of the groove 122a in the extending direction and the edge of the top cover 12 can be the same, that is, the distance between any two positions of the groove 122a in the extending direction and the outer side wall of the connecting side wall 122 can be the same, so that the stress near the groove 122a can be more uniform.

[0120] It should be noted that the top cover 12 can be formed with the groove 122a in a partial region between the cover body 121 and the connecting side wall 122, or can be formed with the groove 122a in the entire region between the cover body 121 and the connecting side wall 122, that is, the top cover 12 is provided with a ring of grooves 122a extending along the edge of the top cover 12. Here, the edge of the top cover 12 refers to the outer side wall of the connecting side wall 122.

[0121] Exemplarily, when the battery monomer 10 is in a cylindrical shape, the top cover 12 can be provided with a ring of grooves 122a extending along the edge of the top cover 12, or can be partially surrounded by the groove 122a.

[0122] When the battery monomer 10 is in a rectangular shape, a partial or entire region of the long side can be formed with the groove 122a, or a partial or entire region of the short side can be formed with the groove 122a. In some embodiments, the top cover 12 is provided with a ring of grooves 122a corresponding to the profile of the top cover 12.

[0123] In some embodiments, referring to FIGS. 5 and 6, in a cross section perpendicular to the extending direction of the groove 122a, the dimension of the groove 122a in the height direction of the battery cell 10 is H1, where 0.5mm≤H1≤2mm. For example, 0.5mm, 0.8mm, 1mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, or 2mm, etc.

[0124] Here, the width of the groove 122a refers to the dimension of the groove 122a in the height direction of the battery cell 10.

[0125] It can be understood that the larger the width of the groove 122a, the more conducive to the force at the connection between the shell 11 and the top cover 12 being transmitted to the groove 122a, i.e., the more conducive to the deformation being concentrated at the groove 122a, but the structural strength of the connecting side wall 122 at the groove 122a is affected.

[0126] In this embodiment, by setting the width of the groove 122a to 0.5mm-2mm, the connecting side wall 122 can have sufficient strength while being conducive to the force at the connection between the shell 11 and the top cover 12 being transmitted to the groove 122a, more conducive to the deformation being concentrated at the groove 122a, thereby reducing the force on the connecting structure between the shell 11 and the top cover 12, reducing the risk of cracking of the connecting structure between the shell 11 and the top cover 12, and improving the service life of the top cover 12.

[0127] In other embodiments, referring to FIGS. 5 and 6, in a cross section perpendicular to the extending direction of the groove 122a, the dimension of the groove 122a in the height direction of the battery cell 10 is H1, where 0.5mm≤H1≤1.5mm. For example, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, or 1.5mm, etc.

[0128] In this embodiment, by setting the width of the groove 122a to 0.5mm-1.5mm, the force at the connection between the shell 11 and the top cover 12 can be transmitted to the groove 122a, which is conducive to the deformation being concentrated at the groove 122a while further enabling the connecting side wall 122 to have sufficient strength, thereby improving the service life of the top cover 12.

[0129] It should be noted that the specific connection manner of the shell 11 and the connecting side wall 122 is not limited herein.

[0130] In some embodiments, referring to FIGS. 5 and 6, the connecting side wall 122 comprises a connecting body 122b and a connecting region 122c arranged at an end of the connecting body 122b away from the cover body 121, an outer side wall of the connecting region 122c is closer to the central axis of the battery cell 10 than the connecting body 122b, and the connecting region 122c extends into the shell 11, and an end surface of the shell 11 is connected to an end surface of the connecting body 122b.

[0131] The connecting side wall 122 comprises a connecting body 122b and a connecting region 122c arranged at an end of the connecting body 122b away from the cover body 121, that is, the connecting side wall 122 comprises the connecting body 122b and the connecting region 122c arranged in sequence along the height direction of the battery cell 10.

[0132] The outer side wall of the connecting region 122c is closer to the central axis of the battery cell 10 than the connecting body 122b, so that a stepped surface away from the cover body 121 is formed between the connecting body 122b and the connecting region 122c.

[0133] The connecting region 122c extends into the shell 11, and an end surface of the shell 11 is connected to an end surface of the connecting body 122b, that is, an end surface of the shell 11 towards the cover body 121 is connected (for example, welded) to the stepped surface formed on the connecting body 122b. In this way, when the shell 11 deforms, it is beneficial to change the stress mode between the shell 11 and the top cover 12 in the related art, thereby improving the strength of the connecting structure of the shell 11 and the top cover 12.

[0134] Here, the outer side wall of the connecting region 122c and the inner side wall of the shell 11 can be in abutment, so that when the shell 11 deforms, the connecting region 122c is beneficial to support the shell 11, thereby improving the strength of the connecting structure of the shell 11 and the top cover 12.

[0135] It can be understood that the outer side wall of the connecting region 122c and the inner side wall of the shell 11 can also be connected together, for example, by welding.

[0136] Of course, the outer side wall of the connecting region 122c and the inner side wall of the shell 11 can also have a certain gap.

[0137] In this embodiment, by setting the distance between the outer side wall of the connecting region 122c and the central axis of the battery monomer 10 to be less than the distance between the connecting body 122b and the central axis of the battery monomer 10, the connecting region 122c is extended into the shell 11 when assembled, and the end surface of the shell 11 is connected with the end surface of the connecting body 122b, so that when the shell 11 is deformed, the stress mode between the shell 11 and the top cover 12 in the related art is changed, and the connecting region 122c is beneficial to support the shell 11, thereby improving the strength of the connecting structure of the shell 11 and the top cover 12.

[0138] In some embodiments, referring to FIG. 5, the outer surface of the connecting body 122b is flush with the outer surface of the cover body 121.

[0139] That is, there is no step surface between the outer surface of the connecting body 122b and the outer surface of the cover body 121. In other words, the distance between the outer surface of the connecting body 122b and the central axis of the battery monomer 10 is equal to the distance between the outer surface of the cover body 121 and the central axis of the battery monomer 10.

[0140] In this embodiment, by setting the outer surface of the connecting body 122b to be flush with the outer surface of the cover body 121, the appearance of the battery monomer 10 is improved, and at the same time, the deposition of dust and other foreign matters between the connecting body 122b and the cover body 121 can be avoided, and the occupied space of the battery monomer 10 can be reduced as much as possible, thereby improving the energy density of the battery 100.

[0141] In some embodiments, referring to FIG. 5, the outer surface of the connecting body 122b is flush with the outer surface of the shell 11.

[0142] That is, there is no step surface between the outer surface of the connecting body 122b and the outer surface of the shell 11. In other words, the distance between the outer surface of the connecting body 122b and the central axis of the battery monomer 10 is equal to the distance between the outer surface of the shell 11 and the central axis of the battery monomer 10.

[0143] In this embodiment, by setting the outer surface of the connecting body 122b to be flush with the outer surface of the shell 11, the appearance of the battery monomer 10 is improved, and at the same time, the deposition of dust and other foreign matters between the connecting body 122b and the shell 11 can be avoided, and the occupied space of the battery monomer 10 can be reduced as much as possible, thereby improving the energy density of the battery 100.

[0144] In some embodiments, referring to FIGS. 5 and 6, the size of the connecting region 122c in the height direction of the battery cell 10 is H2, where 0.5 mm≤H2≤4 mm. For example, 0.5 mm, 0.7 mm, 1 mm, 1.3 mm, 1.5 mm, 1.6 mm, 1.8 mm, 2 mm, 2.2 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.9 mm, 3 mm, 3.2 mm, 3.5 mm, 3.7 mm, 3.9 mm, or 4 mm, and the like.

[0145] It can be understood that the greater the size of the connecting region 122c in the height direction of the battery cell 10, the more conducive to improving the strength of the connecting structure of the shell 11 and the top cover 12, and the smaller the size of the connecting region 122c in the height direction of the battery cell 10, the more conducive to reducing the occupied space of the battery cell 10, thereby improving the energy density of the battery cell 10.

[0146] In this embodiment, by setting the size of the connecting region 122c in the height direction of the battery cell 10 to 0.5 mm-4 mm, the connecting structure of the shell 11 and the top cover 12 has sufficient strength, and the occupied space of the battery cell 10 is small, thereby improving the energy density of the battery cell 10.

[0147] In some embodiments, referring to FIGS. 5 and 6, the size of the connecting side wall 122 in the height direction of the battery cell 10 is H3, where 1.5 mm≤H3≤8 mm. For example, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.2 mm, 4.5 mm, 4.8 mm, 5 mm, 5.3 mm, 5.5 mm, 5.7 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 7.8 mm, or 8 mm, and the like.

[0148] Here, the size of the connecting side wall 122 in the height direction of the battery cell 10 is the height of the connecting side wall 122.

[0149] It can be understood that the greater the size of the connecting side wall 122 in the height direction of the battery cell 10, the more conducive to improving the strength of the connecting structure of the shell 11 and the top cover 12, and the smaller the size of the connecting region 122c in the height direction of the battery cell 10, the more conducive to reducing the occupied space of the battery cell 10, thereby improving the energy density of the battery cell 10.

[0150] In this embodiment, by setting the dimension of the connecting side wall 122 in the height direction of the battery monomer 10 to 1.5 mm-8 mm, the connecting structure of the shell 11 and the top cover 12 can have sufficient strength, and it is beneficial to concentrate the deformation at the groove 122a, while the occupied space of the battery monomer 10 can be smaller, and the energy density of the battery monomer 10 can be improved.

[0151] In some embodiments, as shown in FIGS. 5 and 6, the thickness of the connecting part 122b is L2, and the thickness of the connecting part 122b is L2, wherein 1 mm≤L2≤10L1. That is, the thickness of the connecting part 122b is greater than or equal to 1 mm, and less than or equal to ten times the thickness of the connecting part 122b.

[0152] In this embodiment, by setting the thickness of the connecting part 122b to 1 mm≤L2≤10L1, the connecting part 122b can have sufficient strength, so as to improve the structural strength of the connecting part of the top cover 12 and the shell 11, and it is beneficial to transmit the stress at the connecting part of the shell 11 and the top cover 12 to the groove 122a, so as to concentrate the deformation at the groove 122a, thereby reducing the stress of the connecting structure between the shell 11 and the top cover 12, reducing the risk of cracking of the connecting structure between the shell 11 and the top cover 12, improving the failure problem of the connecting structure between the shell 11 and the top cover 12, and improving the service life of the battery monomer 10.

[0153] In other embodiments, as shown in FIGS. 5 and 6, the thickness of the connecting part 122b is L2, and the thickness of the connecting part 122b is L2, wherein 1 mm≤L2≤4L1. That is, the thickness of the connecting part 122b is greater than or equal to 1 mm, and less than or equal to four times the thickness of the connecting part 122b.

[0154] In this embodiment, by setting the thickness of the connecting part 122b to 1 mm≤L2≤4L1, the connecting part 122b can have sufficient strength, so as to improve the structural strength of the connecting part of the top cover 12 and the shell 11, and it is beneficial to further transmit the stress at the connecting part of the shell 11 and the top cover 12 to the groove 122a, so as to concentrate the deformation at the groove 122a, thereby reducing the stress of the connecting structure between the shell 11 and the top cover 12, further reducing the risk of cracking of the connecting structure between the shell 11 and the top cover 12, improving the failure problem of the connecting structure between the shell 11 and the top cover 12, and improving the service life of the battery monomer 10.

[0155] In some embodiments, referring to Figures 5 and 6 , the height dimension of the cover body 121 in the housing 11 is H4, where 1mm≤H4≤5mm. For example, the height dimension is 1mm, 1.3mm, 1.4mm, 1.5mm, 1.7mm, 2mm, 3mm, 3.3mm, 3.5mm, 3.8mm, 4mm, 4.4mm, 4.5mm, 4.6mm, or 5mm.

[0156] In this embodiment, by setting the height of the cover body 121 to 1mm-5mm, the top cover 12 can have sufficient strength to protect the electrode assembly in the accommodating space 11a, while reducing the weight and volume of the battery cell 10, and reducing the material used in the top cover 12, reducing costs, and improving the overall performance of the battery 100.

[0157] In other embodiments, referring to Figures 5 and 6 , the height dimension of the cover body 121 in the housing 11 is H4, where 1.5 mm ≤ H4 ≤ 3 mm. For example, the height dimension is 1.5 mm, 1.6 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, or 3 mm.

[0158] In this embodiment, by setting the height of the cover body 121 to 1.5mm-3mm, the top cover 12 can have sufficient strength to protect the electrode assembly in the accommodating space 11a, while further reducing the weight and volume of the battery cell 10, reducing the material used in the top cover 12, reducing costs, and further improving the overall performance of the battery 100.

[0159] In some embodiments, referring to FIG5 and FIG6 , the thickness of the connection between the housing 11 and the connecting side wall 122 is L1, where 0.4 mm ≤ L1 ≤ 2 mm, for example, 0.4 mm, 0.5 mm, 0.6 mm, 0.8 mm, 1 mm, 1.3 mm, 1.5 mm, 1.7 mm, 1.8 mm, 1.9 mm, or 2 mm.

[0160] The thickness of the connection portion between the housing 11 and the connecting side wall 122 is L1 , that is, the thickness of the housing 11 near the opening 11 b is L1 .

[0161] It should be noted that the shell 11 may include areas of different thicknesses. For example, along the height direction of the shell 11, the shell 11 includes an area close to one end of the opening 11b and an area away from the end of the opening 11b. By setting the thickness of the area close to one end of the opening 11b to be greater than the thickness of the area away from the end of the opening 11b, the connection strength at the connection between the top cover 12 and the shell 11 can be improved.

[0162] In this embodiment, the thickness of the connection between the shell 11 and the connecting side wall 122 is set to 0.4-2 mm, so that the connection between the top cover 12 and the shell 11 has sufficient connection strength, while reducing the weight and volume of the battery monomer 10, reducing the material of the top cover 12, reducing the cost, and improving the overall performance of the battery 100.

[0163] In other embodiments, referring to FIGS. 5 and 6, the thickness of the connection between the shell 11 and the connecting side wall 122 is L1, where 0.6 mm≤L1≤1.7 mm. For example, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, or 1.7 mm, and the like.

[0164] In this embodiment, the thickness of the connection between the shell 11 and the connecting side wall 122 is set to 0.6-1.7 mm, so that the connection between the top cover 12 and the shell 11 has sufficient connection strength, while further reducing the weight and volume of the battery monomer 10, reducing the material of the top cover 12, reducing the cost, and further improving the overall performance of the battery 100.

[0165] It should be noted that the size H1 of the groove 122a in the height direction of the battery monomer 10, the size H2 of the connecting area 122c in the height direction of the battery monomer 10, the size H3 of the connecting side wall 122 in the height direction of the battery monomer 10, the size H4 of the cover body 121 in the height direction of the shell 11, the thickness L1 of the connection between the shell 11 and the connecting side wall 122, the thickness L2 of the connecting body 122b, and the wall thickness L3 of the connecting side wall 122 at the groove 122a can be obtained by high-precision thickness gauge, vernier caliper and other instruments and calculation when the top cover 12 is not assembled at room temperature.

[0166] The battery monomer 10 of the present disclosure will be further described below in conjunction with specific test examples.

[0167] The test sample of the embodiment of the present disclosure: the top cover 12 is provided with a cover body 121 and a connecting side wall 122, one end of the connecting side wall 122 is connected to the side of the cover body 121 facing the electrode assembly, the other end extends away from the cover body 121, and the shell 11 is connected to the outer side wall of the connecting side wall 122; at least part of the area between the cover body 121 and the shell 11 of the connecting side wall 122 is recessed to form a groove 122a, and the wall thickness of the connecting side wall 122 at the groove 122a is not greater than the thickness of the connection between the shell 11 and the connecting side wall 122.

[0168] The five control groups of the test sample of the embodiment of the present disclosure were subjected to charge-discharge cycle experiments, and the number of cycles was recorded. The cycle numbers of the five control groups of the test sample of the embodiment of the present disclosure were 3010, 3312, 3126, 3385, and 3215, respectively. The average cycle number of the five control groups of the test sample of the embodiment of the present disclosure was 3209. The cycle numbers of the five test samples of the control group were 3863, 3615, 3657, 3742, and 3796, respectively. The average cycle number of the five test samples of the embodiment of the present disclosure was 3734. The average of the test sample of the embodiment of the present disclosure was improved by 16.36% compared with the average of the control group. When the electrode assembly is cycled and expands and gas is generated during charge and discharge, a force is generated at the connection between the shell 11 and the top cover 12. The cycle number of the battery monomer 10 provided by the embodiment of the present disclosure is much larger than that of the control group. That is, the battery monomer 10 provided by the embodiment of the present disclosure reduces the risk of cracking of the connection structure between the shell 11 and the top cover 12, improves the failure problem of the connection structure between the shell 11 and the top cover 12, improves the fatigue performance, reduces the overall weld heat affected deformation strain, and improves the service life of the battery monomer 10.

[0169] In the description of the present disclosure, the description of the terms "in an embodiment", "in some embodiments", "in another embodiment", "in yet another embodiment", or "exemplary" means 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 disclosure. In the present disclosure, the exemplary description of the above terms is not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, different embodiments or examples described in the present disclosure and the features of different embodiments or examples can be combined by those skilled in the art without contradiction.

[0170] The above only describes the preferred embodiments of the present disclosure and is not intended to limit the present disclosure. Those skilled in the art can make various modifications and changes to the present disclosure. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present disclosure is included in the protection scope of the present disclosure.

Claims

1. A battery cell, comprising: a housing having a receiving space and an opening; A top cover and a sealing cover are provided at the opening; an electrode assembly, disposed in the accommodation space; In which, the top cover is provided with a cover body and a connecting side wall, one end of the connecting side wall is connected to the side of the cover body facing the electrode assembly, and the other end extends in a direction away from the cover body, and the outer shell is connected to the connecting side wall; at least a part of the area of ​​the connecting side wall located between the cover body and the outer shell is recessed to form a groove, and the wall thickness of the connecting side wall at the groove is not greater than the thickness at the connection between the outer shell and the connecting side wall.

2. The battery cell according to claim 1, wherein: The inner side wall of the connecting side wall is recessed to form the groove.

3. The battery cell according to claim 1 or 2, wherein: The groove is formed at the connection between the connecting side wall and the cover body.

4. The battery cell according to any one of claims 1 to 3, wherein: The groove extends along an edge of the top cover.

5. The battery cell according to any one of claims 1 to 4, wherein: In a cross section perpendicular to an extending direction of the groove, a dimension of the groove in a height direction of the battery cell is H1, wherein 0.5 mm ≤ H1 ≤ 2 mm.

6. The battery cell according to any one of claims 1 to 5, wherein: In a cross section perpendicular to an extending direction of the groove, a dimension of the groove in a height direction of the battery cell is H1, wherein 0.5 mm ≤ H1 ≤ 1.5 mm.

7. The battery cell according to any one of claims 1 to 6, wherein: The connecting side wall includes a connecting body and a connecting area arranged at one end of the connecting body away from the cover body. The distance between the outer wall of the connecting area and the central axis of the battery cell is smaller than the distance between the connecting body and the central axis of the battery cell. The connecting area extends into the outer shell, and the end face of the outer shell is connected to the end face of the connecting body.

8. The battery cell according to claim 7, wherein: The outer surface of the connecting body is flush with the outer surface of the cover body.

9. The battery cell according to claim 7 or 8, wherein: The outer surface of the connecting body is flush with the outer surface of the housing.

10. The battery cell according to any one of claims 7 to 9, wherein: The dimension of the connection area in the height direction of the battery cell is H2, wherein 0.5 mm ≤ H2 ≤ 4 mm.

11. The battery cell according to any one of claims 7 to 10, wherein: The dimension of the connecting side wall in the height direction of the battery cell is H3, wherein 1.5 mm ≤ H3 ≤ 8 mm.

12. The battery cell according to any one of claims 7 to 11, wherein: The thickness of the connection between the shell and the connection side wall is L1, and the thickness of the connection body is L2, wherein 1mm≤L2≤10L1.

13. The battery cell according to any one of claims 7 to 12, wherein: The thickness of the connection between the shell and the connection side wall is L1, and the thickness of the connection body is L2, wherein 1mm≤L2≤4L1.

14. The battery cell according to any one of claims 1 to 13, wherein: The dimension of the cover body in the height direction of the housing is H4, wherein 1 mm ≤ H4 ≤ 5 mm.

15. The battery cell according to any one of claims 1 to 14, wherein: The dimension of the cover body in the height direction of the housing is H4, wherein 1.5 mm ≤ H4 ≤ 3 mm.

16. The battery cell according to any one of claims 1 to 15, wherein: The thickness of the connection between the shell and the connecting side wall is L1, wherein 0.4 mm ≤ L1 ≤ 2 mm.

17. The battery cell according to any one of claims 1 to 16, wherein: The thickness of the connection between the shell and the connecting side wall is L1, wherein 0.6 mm ≤ L1 ≤ 1.7 mm.

18. A battery comprising at least one battery cell according to any one of claims 1 to 17.

19. An electrical device comprising the battery according to claim 18, wherein the battery is used to provide electrical energy for the electrical device.

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