Battery cell, battery and electric device

Abstract

A battery cell (20), a battery (100) and an electric device, which belong to the technical field of batteries. The battery cell (20) comprises a casing (21) and an electrode assembly (22), wherein the casing (21) has a wall portion (211); the electrode assembly (22) is accommodated in the casing (21); and the casing (21) is made of steel, a pressure relief groove (2111) is provided in the wall portion (211), and the wall portion (211) is configured to be able to crack along at least part of the pressure relief groove (2111) when the battery cell (20) relieves pressure, so as to relieve the internal pressure of the battery cell (20). The battery cell (20) can enhance the structural strength of the casing (21) and the region of the wall portion (211) where the pressure relief groove (2111) is provided, and can alleviate the expansion and deformation of the casing (21) of the battery cell (20) during use, so as to reduce the strain and strain amplitude of the region of the wall portion (211) where the pressure relief groove (2111) is provided, thereby reducing the occurrence of the phenomenon of low-cycle fatigue in the region of the wall portion (211) where the pressure relief groove (2111) is provided, further helping to lower the risk of premature valve opening and pressure relief in the battery cell (20), prolonging the service life of the battery cell (20) and improving the operational reliability thereof.

Description

Battery cell, battery and electric device

[0001] Cross-reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 2024108516074, filed on June 27, 2024, entitled “Battery cell, battery and electric device”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

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

[0004] In recent years, new energy vehicles have made a leap in development. In the field of electric vehicles, power batteries, as the power source of electric vehicles, play an irreplaceable important role. With the vigorous promotion of new energy vehicles, the demand for power battery products is also increasing. Among them, the battery as a core component of new energy vehicles has higher requirements in terms of use reliability and service life.

[0005] In the battery technology, in order to ensure the safety of the battery cell, a pressure relief structure for relieving the internal pressure of the battery cell is generally provided on the shell of the battery cell, so that when the internal pressure or temperature of the battery cell reaches a threshold value, the pressure relief structure can be actuated to relieve the internal pressure of the battery cell. However, the existing pressure relief structure of the battery cell often appears the phenomenon of early actuation of the valve during use, which causes poor use stability of the battery cell, thereby being not conducive to improving the service life and use reliability of the battery cell.

[0006] SUMMARY

[0007] The embodiments of the present application provide a battery cell, a battery and an electric device, which can effectively improve the service life and use reliability of the battery cell.

[0008] In a first aspect, the embodiments of the present application provide a battery cell, comprising a shell and an electrode assembly; the shell has a wall part; the electrode assembly is contained in the shell; wherein the material of the shell is steel, and the wall part is provided with a pressure relief groove, and the wall part is configured to be split along at least part of the pressure relief groove when the battery cell is relieved, so as to relieve the internal pressure of the battery cell.

[0009] In the technical scheme, the shell of the battery monomer is made of steel, and the pressure relief groove is arranged on the wall of the shell, so that the wall can be broken along at least part of the pressure relief groove when the battery monomer is relieved, thereby releasing the internal pressure of the battery monomer. The structure for relieving pressure of the battery monomer is integrally formed on the shell. The battery monomer with the structure can improve the structural strength of the shell and the region of the wall provided with the pressure relief groove, reduce the risk of explosion of the battery monomer during use, and alleviate the phenomenon of swelling and deformation of the shell of the battery monomer during use. This is conducive to reducing the strain and strain amplitude of the region of the wall provided with the pressure relief groove, thereby reducing the phenomenon of low-cycle fatigue of the region of the wall provided with the pressure relief groove, reducing the phenomenon of fatigue damage of the region of the wall provided with the pressure relief groove, and further reducing the risk of early valve relief of the battery monomer, thereby improving the service life and use reliability of the battery monomer.

[0010] In some embodiments, the wall thickness of the wall portion is D1, and 0.075mm≤D1≤0.4mm.

[0011] In the technical scheme, the wall thickness of the wall portion is set to 0.075mm to 0.4mm. On the one hand, the wall thickness of the wall portion is greater than or equal to 0.075mm, which is conducive to improving the structural strength of the wall portion to reduce the risk of damage or cracking of the wall portion, and further alleviate the phenomenon of swelling and deformation of the shell of the battery monomer during use. On the other hand, the wall thickness of the wall portion is less than or equal to 0.4mm, which reduces the difficulty of machining the pressure relief groove on the wall portion, thereby making it easier to set the pressure relief groove on the wall portion, and is conducive to reducing the processing difficulty of the battery monomer.

[0012] In some embodiments, the wall thickness of the wall portion is D1, and 0.075mm≤D1≤0.25mm.

[0013] In the technical scheme, the wall thickness of the wall portion is further set to be less than or equal to 0.25mm, which further reduces the difficulty of machining the pressure relief groove on the wall portion, thereby making it easier to set the pressure relief groove on the wall portion, and is conducive to further reducing the processing difficulty of the battery monomer.

[0014] In some embodiments, along the thickness direction of the wall portion, the minimum residual thickness of the pressure relief groove is D2, and the wall thickness of the wall portion is D1, and 0.08≤D2 / D1≤0.3.

[0015] In the technical scheme, the ratio of the minimum residual thickness of the pressure relief groove to the wall thickness of the wall portion is set to be greater than or equal to 0.08, so as to alleviate the phenomenon of excessive processing of the pressure relief groove on the wall portion, thereby reducing the difficulty of setting the pressure relief groove on the wall portion, improving the structural strength of the region of the wall portion where the pressure relief groove is set, and alleviating the phenomenon of mis-cracking or damage of the region of the wall portion where the pressure relief groove is set, thereby improving the use stability of the battery monomer. On the other hand, the ratio of the minimum residual thickness of the pressure relief groove to the wall thickness of the wall portion is set to be less than or equal to 0.3, so as to alleviate the phenomenon of insufficient depth of the pressure relief groove processed on the wall portion, thereby reducing the burst pressure required for pressure relief of the battery monomer, improving the timeliness of pressure relief of the battery monomer, and reducing the risk of explosion or bursting of the battery monomer in use, thereby improving the use reliability of the battery monomer.

[0016] In some embodiments, along the thickness direction of the wall portion, the wall portion has opposite first and second surfaces, the second surface faces the electrode assembly, the first surface is provided with a first groove, and the wall portion is provided with a first protrusion protruding from the second surface at a position corresponding to the first groove, and the pressure relief groove is arranged on the first protrusion.

[0017] In the technical scheme, the wall portion has a concave-convex structure with a first groove on one side and a first protrusion on the other side, and the pressure relief groove for pressure relief is arranged on the first protrusion. The battery monomer with such a structure can facilitate the processing and forming of the pressure relief groove on the wall portion, improve the material flow pattern of the wall portion during the forming of the pressure relief groove, thereby improving the processing quality of the pressure relief groove and the structural strength of the region of the wall portion where the pressure relief groove is arranged, thereby alleviating the deformation of the region of the wall portion where the pressure relief groove is arranged during use. On the other hand, the pressure relief groove is arranged on the first protrusion protruding into the interior of the battery monomer, which can improve the protection effect of the region of the wall portion where the pressure relief groove is arranged, thereby reducing the wear of the region of the wall portion where the pressure relief groove is arranged during assembly or use, and improving the use stability of the battery monomer.

[0018] In some embodiments, the first protrusion includes a first side wall and a first bottom wall, the first side wall surrounds the first bottom wall, and the first side wall is connected to the first bottom wall, the first side wall and the first bottom wall jointly define the first groove, and the pressure relief groove is arranged on the first bottom wall.

[0019] In the technical solution, the first protrusion comprises a first sidewall and a first bottom wall, the first sidewall is arranged around the first bottom wall, so that the first sidewall and the first bottom wall of the first protrusion together define a first groove, and the pressure relief groove is arranged on the first bottom wall of the first protrusion, so that the pressure relief groove is arranged on the bottom wall of the first groove. The battery cell with the structure has the advantages that on the one hand, the pressure relief groove is easy to be machined on the first protrusion, which is beneficial to reduce the machining difficulty of the pressure relief groove, and on the other hand, the first sidewall can also absorb and buffer part of the stress transmitted from the wall portion to the first bottom wall, so as to reduce the stress impact on the area of the first protrusion provided with the pressure relief groove, and is beneficial to improve the use reliability and stability of the battery cell.

[0020] In some embodiments, the first bottom wall comprises a main body portion and an arch portion, the main body portion connects the arch portion and the first sidewall, and the main body portion is arranged outside the arch portion; along the thickness direction of the wall portion, the arch portion is arched away from the electrode assembly from the main body portion, so as to form a second groove on the side of the first bottom wall facing the electrode assembly and corresponding to the position of the arch portion, and the pressure relief groove is arranged on the main body portion.

[0021] In the technical solution, the first bottom wall of the first protrusion is arranged in a structure of being arched away from the electrode assembly, so that the first bottom wall forms an arch portion and a main body portion arranged outside the arch portion and connecting the arch portion and the first sidewall, and the pressure relief groove is arranged on the main body portion. The structure has the advantages that on the one hand, the difficulty of machining the pressure relief groove on the first bottom wall is reduced, and the material flow form of the first bottom wall during the forming of the pressure relief groove is improved, so as to improve the machining quality of the pressure relief groove; on the other hand, the structural strength of the first bottom wall is further improved, so as to alleviate the deformation of the area of the wall portion provided with the pressure relief groove during use, and improve the use reliability and stability of the battery cell.

[0022] In some embodiments, the pressure relief groove is arranged around the arch portion.

[0023] In the technical solution, the pressure relief groove is arranged in a ring structure around the arch portion, so that after the wall portion is entirely cracked along the pressure relief groove during the pressure relief of the battery cell, the area of the first bottom wall where the arch portion is formed can be entirely separated, which is beneficial to expand the pressure relief area of the battery cell, so as to further improve the pressure relief rate of the battery cell, reduce the risk of explosion or burst of the battery cell due to untimely pressure relief, and effectively improve the use reliability of the battery cell.

[0024] In some embodiments, along the thickness direction of the wall portion, the pressure relief groove is arranged on the side of the main body portion away from the electrode assembly.

[0025] In the technical scheme, the pressure relief groove is arranged on the side of the main body of the first bottom wall away from the electrode assembly, the pressure relief groove is formed on the groove bottom surface of the first groove, and thus the difficulty of forming the pressure relief groove on the main body of the first bottom wall is reduced, the pressure relief groove is formed at the same time of forming the first groove and the arching portion, and thus the processing efficiency of the battery monomer is improved.

[0026] In some embodiments, the pressure relief groove is stamping formed on the main body.

[0027] In the technical scheme, the pressure relief groove is stamping formed on the main body of the first bottom wall, on the one hand, the manufacturing difficulty of the pressure relief groove is reduced, and the processing efficiency of the pressure relief groove is improved, and on the other hand, the first groove and the first protrusion are formed on the wall portion, and the first bottom wall of the first protrusion is formed with the arching portion, so that the material flow of the pressure relief groove is facilitated in the stamping forming process, the processing consistency of the pressure relief groove is improved, and the production quality of the battery monomer is improved.

[0028] In some embodiments, the battery monomer further comprises an insulation piece, the insulation piece is arranged on the side of the wall portion facing the electrode assembly, and the insulation piece is configured to insulate and separate the wall portion and the electrode assembly; wherein, along the thickness direction of the wall portion, the side of the insulation piece facing the wall portion is formed with a avoiding portion, and the avoiding portion accommodates the first protrusion.

[0029] In the technical scheme, the avoiding portion for accommodating the first protrusion is arranged on the side of the insulation piece facing the wall portion, so that the insulation piece can avoid the first protrusion, on the one hand, the interference phenomenon between the first protrusion and the insulation piece or other components is alleviated, and the assembly quality of the battery monomer is improved, and on the other hand, the first protrusion of the wall portion provided with the pressure relief groove is accommodated in the avoiding portion of the insulation piece, so that the insulation piece can also protect the region of the wall portion provided with the pressure relief groove, and the wear or damage phenomenon of the region of the wall portion provided with the pressure relief groove in the assembly process is reduced, thereby improving the production quality of the battery monomer.

[0030] In some embodiments, the insulation piece comprises a body portion and an abutting portion, the body portion is arranged between the wall portion and the electrode assembly along the thickness direction of the wall portion, the abutting portion is connected to the side of the body portion facing the wall portion, and the abutting portion abuts against the second surface; wherein, along the thickness direction of the wall portion, the projection of the abutting portion does not overlap with the projection of the first protrusion, so as to form a spacing space between the body portion and the second surface, and the spacing space is the avoiding portion.

[0031] In the above technical solution, the insulating piece is provided with a body part and an abutting part connected to one side of the body part facing the wall part, by abutting the abutting part on the second surface of the wall part, and the projection of the abutting part in the thickness direction of the wall part does not overlap with the projection of the first protrusion, so that the abutting part is a structure supported between the body part and the wall part, so that the body part and the wall part of the insulating piece are a structure spaced apart in the thickness direction of the wall part, thereby enabling the formation of a spacing space between the body part and the wall part of the insulating piece to avoid the first protrusion, to form an avoiding part for avoiding the first protrusion, simple structure, and easy to assemble.

[0032] In some embodiments, the insulating piece includes a plurality of abutting parts, each of which is connected to one side of the body part facing the wall part, and the plurality of abutting parts are spaced apart.

[0033] In the above technical solution, by connecting a plurality of abutting parts to one side of the body part facing the wall part, and arranging the plurality of abutting parts in a spaced apart manner, the structural stability of the insulating piece assembled between the electrode assembly and the wall part can be further improved, and the effect of the plurality of abutting parts supporting the body part can be improved, thereby improving the overall structural strength of the insulating piece, thereby reducing the phenomenon of deformation or collapse of the body part during use, thereby alleviating the phenomenon of mutual interference between the body part and the first protrusion after deformation, thereby further improving the effect of the insulating piece avoiding the first protrusion.

[0034] In some embodiments, along the thickness direction of the wall part, the minimum distance between the body part and the first protrusion is L, satisfying L≥0.1mm.

[0035] In the above technical solution, by setting the minimum distance between the body part and the first protrusion in the thickness direction of the wall part to be greater than or equal to 0.1mm, the avoiding effect of the avoiding part of the insulating piece on the first protrusion can be further improved, thereby reducing the phenomenon of interference or wear of the first protrusion by the body part of the insulating piece, thereby further improving the assembly quality of the battery monomer.

[0036] In some embodiments, along the thickness direction of the wall part, the wall part has opposite first and second surfaces; wherein the pressure relief groove is provided on the first surface, and the pressure relief groove is located between the first surface and the second surface in the thickness direction of the wall part.

[0037] In the above technical solution, by providing the pressure relief groove on the first surface, and the pressure relief groove is a structure located between the first surface and the second surface in the thickness direction of the wall part, so that the area of the second surface corresponding to the pressure relief groove is not formed with a protruding structure, thereby alleviating the interference phenomenon between the area of the wall part provided with the pressure relief groove and other components, thereby improving the assembly quality of the battery monomer.

[0038] In some embodiments, the first surface is parallel to the second surface.

[0039] In the above technical solution, by setting the first surface and the second surface to be parallel to each other, the interference phenomenon between the region where the wall portion is provided with the pressure relief groove and other components is further alleviated, thereby further improving the assembly quality of the battery monomer.

[0040] In some embodiments, the second surface faces the electrode assembly along the thickness direction of the wall portion.

[0041] In the above technical solution, by setting the second surface to face the electrode assembly, the pressure relief groove is formed on the surface of the side of the wall portion away from the electrode assembly, thereby facilitating the machining of the pressure relief groove on the wall portion, and reducing the difficulty of setting the pressure relief groove on the wall portion, thereby improving the production efficiency of the battery monomer.

[0042] In some embodiments, the pressure relief groove is etched and formed on the wall portion.

[0043] In the above technical solution, the pressure relief groove is formed on the wall portion by etching, so that the pressure relief groove is located between the first surface and the second surface of the wall portion in the thickness direction of the wall portion, thereby facilitating the realization that the second surface does not form a protruding structure corresponding to the region of the pressure relief groove, and reducing the processing difficulty of the pressure relief groove on the wall portion.

[0044] In some embodiments, the pressure relief groove is an annular groove.

[0045] In the above technical solution, by setting the pressure relief groove as an annular groove structure, the wall portion can be completely separated from the inside of the pressure relief groove after the wall portion is completely cracked along the pressure relief groove during the pressure relief of the battery monomer, thereby expanding the pressure relief area of the battery monomer, further improving the pressure relief rate of the battery monomer, reducing the risk of explosion or burst of the battery monomer due to untimely pressure relief, and effectively improving the use reliability of the battery monomer.

[0046] In some embodiments, the shell comprises a shell body and two end covers; the shell body has an accommodating cavity formed therein, the electrode assembly is accommodated in the accommodating cavity, the shell body has two openings formed at opposite ends thereof, and the two openings are in communication with the accommodating cavity; the two end covers respectively seal the two openings; wherein the shell body comprises the wall portion; or one of the two end covers is the wall portion.

[0047] In the technical scheme, the shell body of the shell is provided with an opening at each of the opposite ends, and the two end covers respectively close the two openings. By setting the wall part as one wall of the shell body, the battery monomer with the structure can make the region of the shell provided with the pressure relief groove away from the end cover, thereby effectively relieving the phenomenon that the stress generated by the mutual connection of the end cover and the shell body acts on the region of the wall part provided with the pressure relief groove, reducing the influence on the region of the wall part provided with the pressure relief groove, and further reducing the risk of cracking or structural strength reduction of the region of the wall part provided with the pressure relief groove under the pulling action of the stress, thereby improving the service life and use reliability of the battery monomer. By setting the wall part as one of the two end covers, the battery monomer with the structure is convenient for assembling the battery monomer from the two ends of the shell body, thereby reducing the manufacturing and assembly difficulty of the battery monomer, and facilitating the setting of the pressure relief groove on the end cover, thereby reducing the manufacturing difficulty of the battery monomer and improving the production efficiency of the battery monomer.

[0048] In some embodiments, the shell includes a shell body and an end cover; an accommodating cavity with an opening is formed in the interior of the shell body, and the electrode assembly is accommodated in the accommodating cavity; the end cover closes the opening; wherein the shell body includes the wall part; or the end cover is the wall part.

[0049] In the technical scheme, by setting the wall part of the shell as one wall of the shell body, the battery monomer with the structure can make the region of the shell provided with the pressure relief groove away from the end cover, thereby effectively relieving the phenomenon that the stress generated by the mutual connection of the end cover and the shell body acts on the region of the wall part provided with the pressure relief groove, reducing the influence on the region of the wall part provided with the pressure relief groove, and further reducing the risk of cracking or structural strength reduction of the region of the wall part provided with the pressure relief groove under the pulling action of the stress, thereby improving the service life and use reliability of the battery monomer. By setting the wall part of the shell as the end cover of the shell for closing the opening, the battery monomer with the structure is convenient for setting the pressure relief groove on the end cover, thereby reducing the manufacturing difficulty of the battery monomer and improving the production efficiency of the battery monomer.

[0050] In a second aspect, the embodiments of the present application further provide a battery including the battery monomer.

[0051] In a third aspect, the embodiments of the present application further provide a power consumption device including the battery monomer, and the battery monomer is used to provide electric energy. BRIEF DESCRIPTION OF DRAWINGS

[0052] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as a limitation to the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0053] Fig. 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application;

[0054] Fig. 2 is an exploded structural diagram of a battery according to some embodiments of the present application;

[0055] Fig. 3 is a structural schematic diagram of a battery cell according to some embodiments of the present application;

[0056] Fig. 4 is an exploded structural diagram of a battery cell according to some embodiments of the present application;

[0057] Fig. 5 is a partial sectional view of a battery cell according to some embodiments of the present application;

[0058] Fig. 6 is a partial sectional view of an outer shell of a battery cell according to some embodiments of the present application;

[0059] Fig. 7 is a sectional view of an outer shell of a battery cell according to some embodiments of the present application;

[0060] Fig. 8 is a partial enlarged view of A of the outer shell shown in Fig. 7.

[0061] Fig. 8 is a partial enlarged view of A of the outer shell shown in Fig. 7.

[0062] ​In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0063] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the specification of the present application are only for the purpose of describing the specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion. The terms "first", "second" and the like in the specification and claims of the present application and the above description of drawings are used to distinguish different objects, not to describe a particular order or primary and secondary relationship.

[0064] In the present application, the phrase "embodiment" means that the specific features, structures or properties described in conjunction with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments.

[0065] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection", "attach" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0066] In the present application, the term "and / or" is only a description of the association relationship between the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in the present application generally represents an "or" relationship between the front and rear associated objects.

[0067] In the embodiments of the present application, the same reference signs represent the same components, and for the sake of brevity, the detailed description of the same components is omitted in different embodiments. It should be understood that the thickness, length and width of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length and width of the integrated device, are only exemplary and should not constitute any limitation on the present application.

[0068] As used herein, "a plurality of" means two or more (including two).

[0069] In embodiments of the present application, the battery cell can be a secondary battery, which refers to a battery cell that can be used continuously by activating the active material through charging after discharging the battery cell.

[0070] The battery cell can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc., and the present application is not limited thereto.

[0071] The battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During charging and discharging of the battery cell, active ions (e.g., lithium ions) are inserted and extracted between the positive electrode and the negative electrode. The separator is disposed between the positive electrode and the negative electrode, and can function to prevent short circuiting of the positive and negative electrodes, while allowing the active ions to pass through.

[0072] In some embodiments, the positive electrode can be a positive electrode sheet, which can include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0073] As an example, the positive electrode current collector has two surfaces opposite 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.

[0074] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, aluminum with silver plating on the surface, stainless steel with silver plating on the surface, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, etc. can be used. The composite current collector can include a high molecular 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 high molecular material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0075] As an example, the positive active material can include at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive active material can also be used. These positive active materials can be used alone only one or two or more can be used in combination. Among them, examples of the lithium-containing phosphate can include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (may also be referred to as LFP)), a composite of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite of lithium manganese iron phosphate and carbon. Examples of the lithium transition metal oxide can include, but are not limited to, at least one of lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (may also be referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (may also be referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (may also be referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (may also be referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (may also be referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2), and modified compounds thereof, etc.

[0076] In some embodiments, the positive electrode can employ a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. When the foamed metal is used as the positive electrode, the surface of the foamed metal can not be provided with a positive active material, or of course can be provided with a positive active material. As an example, the foamed metal can also be filled or / and deposited with a lithium source material, a potassium metal, or a sodium metal, the lithium source material being a lithium metal and / or a lithium-rich material.

[0077] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative electrode current collector.

[0078] As an example, the negative current collector can employ a metal foil, a foamed metal, or a composite current collector. For example, as the metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, nickel, or titanium, etc. can be employed. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. 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 (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0079] As an example, the negative electrode sheet can include a negative current collector and a negative active material disposed on at least one surface of the negative current collector.

[0080] As an example, the negative current collector has two surfaces opposite in the thickness direction thereof, and the negative active material is disposed on either one or both of the two opposite surfaces of the negative current collector.

[0081] As an example, the negative active material can employ a negative active material for a battery cell known in the art. As an example, the negative active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, and 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 application is not limited to these materials, and other conventional materials that can be used as a battery negative active material can also be used. These negative active materials can be used alone only one or in combination of two or more.

[0082] In some embodiments, the material of the positive current collector can be aluminum, and the material of the negative current collector can be copper.

[0083] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0084] In some embodiments, the separator is a separator film. The type of the separator film can be various, and any known porous structure separator film having good chemical stability and mechanical stability can be used.

[0085] As an example, the material of the separator film can include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator film can be a single layer film or a multi-layer composite film. When the separator film is a multi-layer composite film, the materials of the layers can be the same or different. The separator can be a separate component located between the positive and negative electrodes or can be attached to the surface of the positive and negative electrodes.

[0086] In some embodiments, the separator is a solid-state electrolyte. The solid-state electrolyte is disposed between the positive and negative electrodes and functions to transport ions and separate the positive and negative electrodes.

[0087] In some embodiments, the battery cell further includes an electrolyte that functions to conduct ions between the positive and negative electrodes. The electrolyte can be in a liquid, gel, or solid state. Among them, the liquid electrolyte includes an electrolyte salt and a solvent.

[0088] In some embodiments, the electrolyte salt can include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoroboric oxalate, lithium bisoxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorodioxalate phosphate.

[0089] In some embodiments, the solvent can include at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, butanediol sulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent can also be an ether solvent. The ether solvent can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ether.

[0090] Among them, the gel electrolyte includes a polymer as a skeleton network of the electrolyte, in combination with an ionic liquid-lithium salt.

[0091] Among them, the solid-state electrolyte includes a polymer solid-state electrolyte, an inorganic solid-state electrolyte, and a composite solid-state electrolyte.

[0092] As an example, the polymer solid-state electrolyte can be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single-ion polymer, a polyionic liquid-lithium salt, cellulose, etc.

[0093] As an example, the inorganic solid-state electrolyte can include one or more of an oxide solid-state electrolyte (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON thin film), a sulfide solid-state electrolyte (crystalline lithium superionic conductor (lithium germanium phosphorous sulfide, argyrodite), amorphous sulfide), and a halide solid-state electrolyte, a nitride solid-state electrolyte, and a hydride solid-state electrolyte.

[0094] As an example, the composite solid-state electrolyte is formed by adding an inorganic solid-state electrolyte filler to a polymer solid-state electrolyte.

[0095] In some embodiments, the electrode assembly is in a jelly-roll structure. The positive electrode sheet and the negative electrode sheet are wound into the jelly-roll structure.

[0096] In some embodiments, the electrode assembly is in a stack structure.

[0097] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets can be provided, and the plurality of positive electrode sheets and the plurality of negative electrode sheets are alternately stacked.

[0098] As an example, a plurality of positive electrode sheets can be provided, and the negative electrode sheet is folded to form a plurality of folded segments that are stacked. One positive electrode sheet is clamped between adjacent folded segments.

[0099] As an example, the positive electrode sheet and the negative electrode sheet are both folded to form a plurality of folded segments that are stacked.

[0100] As an example, a plurality of separators can be provided, and each of the plurality of separators is provided between any adjacent positive electrode sheet or negative electrode sheet.

[0101] As an example, the separators can be continuously provided, and are provided between any adjacent positive electrode sheet or negative electrode sheet by folding or winding.

[0102] In some embodiments, the electrode assembly can have a cylindrical shape, a flat shape, or a multi-prism shape, etc.

[0103] In some embodiments, the electrode assembly can be provided with tabs. The tabs can guide current out of the electrode assembly. The tabs include positive tabs and negative tabs.

[0104] In some embodiments, the battery cell can include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum-plastic film, etc.

[0105] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. The prismatic battery cell includes, but is not limited to, a square battery cell, a blade-shaped battery cell, a multi-prismatic battery cell, and a multi-prismatic battery cell such as a hexagonal battery cell, etc.

[0106] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery monomers to provide higher voltage and capacity.

[0107] In some embodiments, the battery can be a battery module, and when there are multiple battery monomers, the multiple battery monomers are arranged and fixed to form a battery module.

[0108] In some embodiments, the battery can be a battery pack, and the battery pack includes a box body and battery monomers or battery modules contained in the box body.

[0109] In some embodiments, the box body can be part of the chassis structure of the vehicle. For example, part of the box body can be at least part of the floor of the vehicle, or part of the box body can be at least part of the cross beam and longitudinal beam of the vehicle.

[0110] In some embodiments, the battery can be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0111] The battery has the outstanding advantages of high energy density, small environmental pollution, large power density, long service life, wide adaptation range, and small self-discharge coefficient, and is an important part of the development of new energy today. The development of battery technology needs to consider many design factors, such as energy density, cycle life, discharge capacity, and charge-discharge rate performance parameters, and the safety of the battery.

[0112] For a general battery monomer, in order to ensure the use safety of the battery monomer, a pressure relief structure is usually arranged on the shell of the battery monomer to release the internal pressure of the battery monomer through the pressure relief structure, thereby effectively improving the use safety of the battery monomer. In related technologies, the shell of the battery monomer is usually made of aluminum, so that the structural strength of the shell of the battery monomer is weak, and the battery monomer is prone to swelling and deformation during use, which causes a large strain and strain amplitude of the pressure relief structure on the shell, so that the pressure relief structure is prone to early valve relief, the pressure relief structure arranged on the wall portion is prone to low-cycle fatigue, and the use stability of the pressure relief structure arranged on the wall portion is poor, which is not conducive to improving the service life and use reliability of the battery monomer.

[0113] Based on the above considerations, in order to solve the problems of short service life and low use reliability of the battery monomer, the embodiments of the present application provide a battery monomer, which includes a shell and an electrode assembly. The shell has a wall portion. The electrode assembly is contained in the shell. The shell is made of steel, and the wall portion is provided with a pressure relief groove, and the wall portion is configured to be split along at least part of the pressure relief groove to release the internal pressure of the battery monomer when the battery monomer is relieved.

[0114] In the battery cell with the above structure, by setting the shell of the battery cell as a steel material and setting the pressure relief groove on the wall of the shell, the wall can be broken along at least part of the pressure relief groove when the battery cell is relieved of pressure, thereby releasing the internal pressure of the battery cell, so that the structure for relieving pressure of the battery cell is integrated on the shell. The battery cell with the above structure can improve the structural strength of the shell and the structural strength of the region of the wall provided with the pressure relief groove, reduce the risk of explosion of the battery cell during use, and alleviate the phenomenon of swelling and deformation of the shell of the battery cell during use, thereby reducing the strain and strain amplitude of the region of the wall provided with the pressure relief groove, reducing the phenomenon of low-cycle fatigue of the region of the wall provided with the pressure relief groove, reducing the phenomenon of fatigue damage of the region of the wall provided with the pressure relief groove, and further reducing the risk of early valve relief of the battery cell, thereby improving the service life and use reliability of the battery cell.

[0115] The battery cell disclosed in the embodiments of the present application can be used in an electric device such as a vehicle, a ship or an aircraft, but is not limited thereto. The power supply system of the electric device can be composed of the battery cell and the battery disclosed in the present application, so that the problem of early actuation of the valve of the battery cell during use can be alleviated, thereby improving the service life and use reliability of the battery cell.

[0116] The embodiments of the present application provide an electric device using a battery as a power supply. The electric device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, etc. The electric toy can include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, an electric plane toy, etc. The spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0117] The following embodiments are described with reference to a vehicle as an example of an electric device of an embodiment of the present application for convenience of description.

[0118] Please refer to FIG. 1, which is a structural schematic diagram of a vehicle 1000 provided by some embodiments of the present application. The vehicle 1000 can be a fuel automobile, a gas automobile, or a new energy automobile, which can be a pure electric automobile, a hybrid automobile, or a range extended automobile, etc. The vehicle 1000 is internally provided with a battery 100, which can be arranged at the bottom of the vehicle 1000, or at the head of the vehicle 1000, or at the tail of the vehicle 1000. The battery 100 can be used to supply power for the vehicle 1000, for example, the battery 100 can be used as an operating power source or a usage power source of the vehicle 1000, etc. The vehicle 1000 can further include a controller 200 and a motor 300, the controller 200 is used to control the battery 100 to supply power for the motor 300, for example, to meet the power demand of the vehicle 1000 during starting, navigation, and driving.

[0119] In some embodiments of the present application, the battery 100 can not only be used as an operating power source or a usage power source of the vehicle 1000, but also be used 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.

[0120] Please refer to FIG. 2 and FIG. 3, FIG. 2 is an exploded structural diagram of the battery 100 provided by some embodiments of the present application, and FIG. 3 is a structural schematic diagram of a battery monomer 20 provided by some embodiments of the present application. The battery 100 includes a box body 10 and the battery monomer 20, and the battery monomer 20 is used to be accommodated in the box body 10.

[0121] The box body 10 is used to provide an assembly space for the battery monomer 20, and the box body 10 can adopt various structures. In some embodiments, the box body 10 can include a first box body 11 and a second box body 12, the first box body 11 and the second box body 12 are mutually covered, and the first box body 11 and the second box body 12 jointly define an assembly space for accommodating the battery monomer 20. The second box body 12 can be a hollow structure with one end open, and the first box body 11 can be a plate-shaped structure, which is covered on the open side of the second box body 12 to jointly define the assembly space with the second box body 12; the first box body 11 and the second box body 12 can also be hollow structures with one side open, and the open side of the first box body 11 is covered on the open side of the second box body 12.

[0122] Of course, the box body 10 formed by the first box body 11 and the second box body 12 can have various shapes, such as a cylinder, a cuboid, or a square, etc. Exemplarily, in FIG. 2, the shape of the box body 10 is a cuboid.

[0123] In the battery 100, the battery cell 20 arranged in the case 10 can be one or multiple. When the battery cell 20 arranged in the case 10 is multiple, the multiple battery cells 20 can be connected in series, in parallel or in a mixed connection, where the mixed connection means that the multiple battery cells 20 are connected in series and in parallel. The multiple battery cells 20 can be directly connected in series, in parallel or in a mixed connection, and then the whole of the multiple battery cells 20 is accommodated in the case 10. Of course, the battery 100 can also be that the multiple battery cells 20 are first connected in series, in parallel or in a mixed connection to form a battery module, and then the multiple battery modules are connected in series, in parallel or in a mixed connection to form a whole, and the whole is accommodated in the case 10.

[0124] In some embodiments, the battery 100 can further include other structures, for example, the battery 100 can further include a busbar component for connecting the multiple battery cells 20 to realize the electrical connection between the multiple battery cells 20.

[0125] Each battery cell 20 can be a secondary battery or a primary battery, and can also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto. The battery cell 20 can be in the shape of a cuboid, a cylinder, a prism or other shapes. For example, in FIG. 3, the battery cell 20 is in the shape of a cuboid.

[0126] According to some embodiments of the present application, referring to FIG. 3, and further referring to FIG. 4 and FIG. 5, FIG. 4 is an exploded view of the structure of the battery cell 20 according to some embodiments of the present application, and FIG. 5 is a partial cross-sectional view of the battery cell 20 according to some embodiments of the present application. The present application provides a battery cell 20, which includes a shell 21 and an electrode assembly 22. The shell 21 has a wall portion 211, and the electrode assembly 22 is accommodated in the shell 21. The shell 21 is made of steel, and the wall portion 211 is provided with a pressure relief groove 2111, and the wall portion 211 is configured to be split along at least part of the pressure relief groove 2111 when the battery cell 20 is relieved of pressure, so as to release the internal pressure of the battery cell 20.

[0127] The shell 21 can also be used to accommodate an electrolyte, for example, an electrolyte solution. The shell 21 can be in various structural forms, such as a cylinder, a cuboid or a prism structure. The shell 21 is made of steel, which can be low-carbon steel, medium-carbon steel or high-carbon steel, etc.

[0128] In some embodiments, referring to FIG. 4, the shell 21 can include a housing 212 and two end covers 213, the housing 212 being a hollow structure with openings 2121 on opposite sides, and one end cover 213 corresponding to cover the opening 2121 of the housing 212 and form a sealed connection to form a sealed space for accommodating the electrode assembly 22 and the electrolyte, that is, the housing 212 is formed with openings 2121 on opposite sides, and the two end covers 213 cover the two sides of the housing 212 respectively to close the corresponding openings 2121.

[0129] Optionally, the wall portion 211 provided with the pressure relief groove 2111 can be one of the two end covers 213 of the shell 21, or one of the walls of the housing 212. In the example shown in FIG. 4, the wall portion 211 provided with the pressure relief groove 2111 is one of the walls of the housing 212. Of course, the structure of the battery monomer 20 is not limited to this, and in other embodiments, the battery monomer 20 can also have other structures, for example, the wall portion 211 provided with the pressure relief groove 2111 can also be one of the two end covers 213 of the shell 21.

[0130] Of course, it is understandable that the shell 21 is not limited to the above structure, and the shell 21 can also have other structures, for example, the shell 21 can include a housing 212 and an end cover 213, the inside of the housing 212 is formed with an accommodation cavity for accommodating the electrode assembly 22, and the accommodation cavity has an opening 2121, that is, the housing 212 is a hollow structure with an opening 2121 at one end, and the end cover 213 covers the opening 2121 of the housing 212 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 22 and the electrolyte. The housing 212 includes a second bottom wall and a second side wall formed integrally, the second side wall surrounds the second bottom wall, one end of the second side wall is connected to the second bottom wall, and the other end forms the opening 2121, the end cover 213 covers the opening 2121 and is arranged opposite to the second bottom wall, and the second bottom wall and the second side wall together define the accommodation cavity for accommodating the electrode assembly 22. In this embodiment, the wall portion 211 provided with the pressure relief groove 2111 can be the end cover 213 of the shell 21, or one of the walls of the second bottom wall or the second side wall of the housing 212.

[0131] In assembling the battery monomer 20, the electrode assembly 22 can be first placed in the housing 212, and then the electrolyte is filled into the housing 212, and then the end cover 213 is covered on the opening 2121 of the housing 212 to complete the assembly of the battery monomer 20.

[0132] The shell 21 can be in various shapes, such as a cylinder, a cuboid, etc. The shape of the shell 21 can be determined according to the specific shape of the electrode assembly 22. For example, if the electrode assembly 22 is in a cylindrical structure, the shell 21 can be in a cylindrical structure; if the electrode assembly 22 is in a cuboid structure, the shell 21 can be in a cuboid structure. Exemplarily, in FIGS. 3 and 4, the shell 21 is in a cuboid structure.

[0133] In the embodiment of the present application, the wall portion 211 is provided with a pressure relief groove 2111, and the wall portion 211 is configured to be able to crack along at least part of the pressure relief groove 2111 when the battery monomer 20 is relieved of pressure, so as to release the internal pressure of the battery monomer 20, that is, the region where the wall portion 211 is provided with the pressure relief groove 2111 forms a weak structure of the wall portion 211, which is a pressure relief structure for the battery monomer 20 to release the internal pressure of the battery monomer 20, so that when the internal pressure or temperature of the battery monomer 20 reaches a predetermined value, the wall portion 211 can crack along at least part of the groove bottom wall of the pressure relief groove 2111 to release the internal pressure of the battery monomer 20, that is, the pressure relief component for the battery monomer 20 to relieve pressure is integrally formed on the wall portion 211 of the shell 21.

[0134] Optionally, the pressure relief groove 2111 can be provided on the surface of the side of the wall portion 211 facing the electrode assembly 22, or on the surface of the side of the wall portion 211 away from the electrode assembly 22. Similarly, the shape of the pressure relief groove 2111 can also be various, such as a strip-shaped structure extending along a straight trajectory, a "U"-shaped structure, a "V"-shaped structure, an "S"-shaped structure, an "N"-shaped structure, an "H"-shaped structure, a "Y"-shaped structure, a double "Y"-shaped structure, a rectangular structure, a triangular structure, a circular structure, or an elliptical structure, etc. In addition, the pressure relief groove 2111 can be a multi-stage groove provided along the thickness direction X of the wall portion, or can be only a one-stage groove.

[0135] Exemplarily, the pressure relief groove 2111 is provided on the surface of the side of the wall portion 211 away from the electrode assembly 22, and the pressure relief groove 2111 is in an annular groove structure.

[0136] It should be noted that the electrode assembly 22 is a component in which an electrochemical reaction occurs in the battery monomer 20, and the structure of the electrode assembly 22 can be various, such as a winding type structure formed by winding a positive electrode sheet, a separator, and a negative electrode sheet, or a laminated type structure formed by laminating a positive electrode sheet, a separator, and a negative electrode sheet.

[0137] Exemplarily, the separator is a separator film, and the main material of the separator film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride.

[0138] In FIG. 4, the battery monomer 20 includes two electrode terminals 23, which are respectively insulatedly mounted on the two end covers 213. Correspondingly, the electrode assembly 22 is formed with the tabs 221 at both ends in the thickness direction of the end cover 213, and the polarity of the tabs 221 at both ends of the electrode assembly 22 is opposite, so as to respectively input or output the positive electrode and the negative electrode of the electrode assembly 22, and the tabs 221 at both ends of the electrode assembly 22 are respectively electrically connected with the two electrode terminals 23. It should be noted that the tabs 221 of the electrode assembly 22 are components formed by stacking the regions without the positive active material layer on the positive plate or the regions without the negative active material layer on the negative plate. If the tab 221 is used to output the positive electrode of the electrode assembly 22, the tab 221 is a component formed by stacking the regions without the positive active material layer on the positive plate; if the tab 221 is used to output the negative electrode of the electrode assembly 22, the tab 221 is a component formed by stacking the regions without the negative active material layer on the negative plate.

[0139] Of course, the structure of the battery monomer 20 is not limited to this, and in other embodiments, the two electrode terminals 23 can be provided on the same end cover 213, or can be provided on the shell 212, or one electrode terminal 23 can be provided on the end cover 213 and the other electrode terminal 23 can be provided on the shell 212.

[0140] Optionally, the electrode assembly 22 accommodated in the shell 21 can be one or multiple. For example, in FIG. 4, the shell 21 of the battery monomer 20 is provided with only one electrode assembly 22. Of course, in other embodiments, the electrode assembly 22 accommodated in the shell 21 can also be two, three, four, five, six, seven or eight, etc.

[0141] The electrode terminal 23 serves to input or output the electric energy of the battery monomer 20, and the electrode terminal 23 is electrically connected with the tab 221 to input or output the electric energy of the battery monomer 20. It should be noted that the electrode terminal 23 is insulatedly mounted on the end cover 213 of the shell 21, that is, no electrical connection is formed between the electrode terminal 23 and the end cover 213 of the shell 21.

[0142] Optionally, the material of the electrode terminal 23 can also be various, such as copper, iron, aluminum, steel or aluminum alloy, etc.

[0143] In some embodiments, the battery cell 20 can further include two current collecting members, both of which are arranged in the shell 21, and each of which is used to connect one electrode terminal 23 and the same-polarity tab 221 in the electrode assembly 22, so as to realize the electrical connection between the electrode terminal 23 and the electrode assembly 22, and facilitate the reduction of the assembly difficulty between the tab 221 and the electrode terminal 23.

[0144] Exemplarily, the material of the current collecting member can also be various, for example, the material of the current collecting member can be copper, iron, aluminum, steel or aluminum alloy, etc.

[0145] In the present embodiment, by setting the shell 21 of the battery cell 20 to be made of steel, and setting the pressure relief groove 2111 on the wall portion 211 of the shell 21, the wall portion 211 can be split along at least part of the pressure relief groove 2111 when the battery cell 20 is relieved of pressure, so as to release the internal pressure of the battery cell 20, so that the structure for relieving pressure of the battery cell 20 is integrally formed on the shell 21. The battery cell 20 adopting such structure can improve the structural strength of the shell 21 and the structural strength of the region of the wall portion 211 provided with the pressure relief groove 2111, can reduce the explosion risk of the battery cell 20 during use, and can alleviate the phenomenon of swelling deformation of the shell 21 of the battery cell 20 during use, which is conducive to reducing the strain and strain amplitude of the region of the wall portion 211 provided with the pressure relief groove 2111, so as to reduce the low-cycle fatigue phenomenon of the region of the wall portion 211 provided with the pressure relief groove 2111, to reduce the fatigue damage phenomenon of the region of the wall portion 211 provided with the pressure relief groove 2111, and further to reduce the risk of early valve relief pressure of the battery cell 20, so as to improve the service life and use reliability of the battery cell 20.

[0146] According to some embodiments of the present application, referring to FIG. 5, and further referring to FIG. 6, which is a partial sectional view of the shell 21 of the battery cell 20 provided by some embodiments of the present application. The wall thickness of the wall portion 211 is D1, which satisfies 0.075mm≤D1≤0.4mm.

[0147] In the formula, the wall thickness D1 of the wall portion 211 is the thickness of the main region of the wall portion 211 in the thickness direction X of the wall portion, that is, the thickness of the region of the wall portion 211 which is not provided with the pressure relief groove 2111 and which is not formed with the first groove 2114 and the first protrusion 2115 in the thickness direction X of the wall portion.

[0148] Exemplarily, the wall thickness D1 of the wall portion 211 can be 0.075 mm, 0.08 mm, 0.085 mm, 0.09 mm, 0.095 mm, 0.1 mm, 0.11 mm, 0.12 mm, 0.15 mm, 0.18 mm, 0.2 mm, 0.22 mm, 0.25 mm, 0.3 mm, 0.35 mm, or 0.4 mm, etc.

[0149] In this embodiment, by setting the wall thickness of the wall portion 211 to be 0.075 mm to 0.4 mm, on the one hand, the wall thickness of the wall portion 211 is set to be greater than or equal to 0.075 mm, which is conducive to improving the structural strength of the wall portion 211, so as to reduce the risk of damage or cracking of the wall portion 211, and can further alleviate the phenomenon of swelling and deformation of the shell 21 of the battery monomer 20 during use, on the other hand, the wall thickness of the wall portion 211 is set to be less than or equal to 0.4 mm, so as to reduce the difficulty of processing the pressure relief groove 2111 on the wall portion 211, so that it is easier to set the pressure relief groove 2111 on the wall portion 211, which is conducive to reducing the processing difficulty of the battery monomer 20.

[0150] In some embodiments, please continue to refer to FIGS. 5 and 6, the wall thickness of the wall portion 211 is D1, which satisfies 0.075 mm≤D1≤0.25 mm.

[0151] In this embodiment, by further setting the wall thickness of the wall portion 211 to be less than or equal to 0.25 mm, the difficulty of processing the pressure relief groove 2111 on the wall portion 211 is further reduced, so that it is easier to set the pressure relief groove 2111 on the wall portion 211, which is conducive to further reducing the processing difficulty of the battery monomer 20.

[0152] According to some embodiments of the present application, please refer to FIG. 6, along the thickness direction X of the wall portion, the minimum residual thickness of the pressure relief groove 2111 is D2, and the wall thickness of the wall portion 211 is D1, which satisfies 0.08≤D2 / D1≤0.3.

[0153] Wherein, the minimum residual thickness D2 of the pressure relief groove 2111 is the minimum thickness of the groove bottom wall of the pressure relief groove 2111 in the thickness direction X of the wall portion, and is also the minimum residual thickness of the region of the wall portion 211 provided with the pressure relief groove 2111.

[0154] Exemplarily, the minimum residual thickness D2 of the pressure relief groove 2111 and the wall thickness D1 of the wall portion 211 can be 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.18, 0.2, 0.22, 0.25, 0.26, 0.28, or 0.3, etc.

[0155] In this embodiment, by setting the ratio of the minimum residual thickness of the pressure relief groove 2111 to the wall thickness of the wall portion 211 to 0.08 to 0.3, on the one hand, the ratio of the minimum residual thickness of the pressure relief groove 2111 to the wall thickness of the wall portion 211 is set to be greater than or equal to 0.08 to alleviate the phenomenon of excessive machining of the pressure relief groove 2111 on the wall portion 211, thereby being able to reduce the difficulty of setting the pressure relief groove 2111 on the wall portion 211, and being able to improve the structural strength of the area of the wall portion 211 where the pressure relief groove 2111 is set, which is beneficial to alleviate the phenomenon of mis-cracking or damage of the area of the wall portion 211 where the pressure relief groove 2111 is set, thereby being able to improve the use stability of the battery monomer 20, on the other hand, the ratio of the minimum residual thickness of the pressure relief groove 2111 to the wall thickness of the wall portion 211 is set to be less than or equal to 0.3 to alleviate the phenomenon of insufficient depth of the pressure relief groove 2111 machined on the wall portion 211, thereby being able to reduce the burst pressure required for the pressure relief of the battery monomer 20, which is beneficial to improve the timeliness of the pressure relief of the battery monomer 20, thereby being able to reduce the risk of explosion or bursting of the battery monomer 20 during use, to improve the use reliability of the battery monomer 20.

[0156] According to some embodiments of the present application, as shown in FIGS. 5 and 6, along the thickness direction X of the wall portion, the wall portion 211 has opposite first and second surfaces 2112 and 2113, the second surface 2113 faces the electrode assembly 22, the first surface 2112 is provided with a first groove 2114, and the wall portion 211 has a first protrusion 2115 protruding from the second surface 2113 at a position corresponding to the first groove 2114, and the pressure relief groove 2111 is arranged on the first protrusion 2115.

[0157] Wherein, the wall portion 211 has opposite first and second surfaces 2112 and 2113, the second surface 2113 faces the electrode assembly 22, that is, the wall portion 211 has the second surface 2113 facing the electrode assembly 22 and the first surface 2112 facing away from the electrode assembly 22 in the thickness direction X of the wall portion.

[0158] The first surface 2112 is provided with a first groove 2114, and the wall portion 211 has a first protrusion 2115 protruding from the second surface 2113 at a position corresponding to the first groove 2114, that is, the wall portion 211 is a structure that is recessed on one side and protrudes on the other side by stamping, so that the wall portion 211 is a structure that is recessed on one side and protrudes on the other side by stamping.

[0159] The pressure relief groove 2111 is arranged on the first protrusion 2115, that is, the weak structure formed by the wall portion 211 and the pressure relief groove 2111 is located on the first protrusion 2115. Alternatively, the pressure relief groove 2111 can be arranged on the bottom wall of the first groove 2114 or on the bottom wall of the first groove 2114.

[0160] In this embodiment, the wall portion 211 is a concave-convex structure in which one side forms the first groove 2114 and the other side forms the first protrusion 2115, and the pressure relief groove 2111 for pressure relief is arranged on the first protrusion 2115. By adopting this structure, on the one hand, the battery monomer 20 facilitates the forming of the pressure relief groove 2111 on the wall portion 211, is beneficial to improving the material flow form of the wall portion 211 in the process of forming the pressure relief groove 2111, thereby improving the processing quality of the pressure relief groove 2111 and improving the structural strength of the region of the wall portion 211 for arranging the pressure relief groove 2111, thereby relieving the deformation of the region of the wall portion 211 provided with the pressure relief groove 2111 during use, and on the other hand, the pressure relief groove 2111 is arranged on the first protrusion 2115 of the wall portion 211 protruding into the interior of the battery monomer 20, which is beneficial to improving the protection effect of the region of the wall portion 211 provided with the pressure relief groove 2111, thereby reducing the wear of the region of the wall portion 211 provided with the pressure relief groove 2111 during assembly or use, so as to improve the use stability of the battery monomer 20.

[0161] According to some embodiments of the present application, please continue to refer to FIGS. 5 and 6, the first protrusion 2115 includes a first side wall 21151 and a first bottom wall 21152, the first side wall 21151 surrounds the first bottom wall 21152, and the first side wall 21151 is connected to the first bottom wall 21152, the first side wall 21151 and the first bottom wall 21152 jointly define the first groove 2114, and the pressure relief groove 2111 is arranged on the first bottom wall 21152.

[0162] Among them, the first side wall 21151 of the first protrusion 2115 is also the groove side wall of the first groove 2114, so that the first side wall 21151 connects the first bottom wall 21152 and the part of the wall portion 211 which does not form the first protrusion 2115. Correspondingly, the first bottom wall 21152 of the first protrusion 2115 is also the groove bottom wall of the first groove 2114, so that the first side wall 21151 and the first bottom wall 21152 of the first protrusion 2115 are structures that jointly surround and define the first groove 2114.

[0163] The pressure relief groove 2111 is arranged on the first bottom wall 21152, that is, the pressure relief groove 2111 is arranged on the groove bottom wall of the first recess 2114. Exemplarily, in FIG. 6, the pressure relief groove 2111 is arranged on the surface of the side of the first bottom wall 21152 away from the electrode assembly 22, that is, the pressure relief groove 2111 is arranged on the groove bottom surface of the first recess 2114. Of course, the structure of the battery monomer 20 is not limited to this. In other embodiments, the battery monomer 20 can also have other structures. For example, the pressure relief groove 2111 can also be arranged on the surface of the side of the first bottom wall 21152 facing the electrode assembly 22.

[0164] In this embodiment, the first protrusion 2115 includes the first side wall 21151 and the first bottom wall 21152, and the first side wall 21151 is arranged around the first bottom wall 21152 to jointly define the first recess 2114 with the first side wall 21151 and the first bottom wall 21152 of the first protrusion 2115. By arranging the pressure relief groove 2111 on the first bottom wall 21152 of the first protrusion 2115, the pressure relief groove 2111 is arranged on the groove bottom wall of the first recess 2114. The battery monomer 20 with this structure can facilitate the machining of the pressure relief groove 2111 on the first protrusion 2115, which is conducive to reducing the machining difficulty of the pressure relief groove 2111. On the other hand, the first side wall 21151 can also absorb and buffer part of the stress transmitted from the wall portion 211 to the first bottom wall 21152, so as to reduce the stress impact on the area of the first protrusion 2115 provided with the pressure relief groove 2111, and improve the use reliability and stability of the battery monomer 20.

[0165] According to some embodiments of the present application, referring to FIG. 6, the first bottom wall 21152 can include a main body portion 21152a and an arch portion 21152b, the main body portion 21152a is connected to the arch portion 21152b and the first side wall 21151, and the main body portion 21152a is arranged outside the arch portion 21152b. Along the thickness direction X of the wall portion, the arch portion 21152b arches away from the electrode assembly 22 from the main body portion 21152a to form a second recess 21152c on the side of the first bottom wall 21152 facing the electrode assembly 22 and corresponding to the position of the arch portion 21152b, and the pressure relief groove 2111 is arranged on the main body portion 21152a.

[0166] The first bottom wall 21152 is partially arched in the direction away from the electrode assembly 22 in the thickness direction X of the wall portion and forms an arch portion 21152b, and the region of the first bottom wall 21152 that is not arched and connects the first side wall 21151 and the arch portion 21152b is a main body portion 21152a, so that the main body portion 21152a is an annular structure surrounding the outside of the arch portion 21152b, and so that the first bottom wall 21152 forms a second groove 21152c at the position corresponding to the arch portion 21152b on the side facing the electrode assembly 22.

[0167] The pressure relief groove 2111 is arranged on the main body portion 21152a, that is, the pressure relief groove 2111 is located between the arch portion 21152b and the first side wall 21151.

[0168] It should be noted that the first groove 2114, the first protrusion 2115, the pressure relief groove 2111, and the arch portion 21152b of the wall portion 211 are all structures formed by a stamping process, so that the wall portion 211 is formed with a structure protruding to both sides in the thickness direction X of the wall portion, so as to facilitate the flow pattern of the material during the stamping forming of the pressure relief groove 2111 and reduce the stamping forming difficulty of the pressure relief groove 2111.

[0169] In this embodiment, by arranging the part of the first bottom wall 21152 of the first protrusion 2115 to be arched in the direction away from the electrode assembly 22, the first bottom wall 21152 is formed with an arch portion 21152b and a main body portion 21152a surrounding the outside of the arch portion 21152b and connecting the arch portion 21152b and the first side wall 21151, and by arranging the pressure relief groove 2111 on the main body portion 21152a, on the one hand, the difficulty of processing the pressure relief groove 2111 on the first bottom wall 21152 is reduced, and it is beneficial to improve the flow pattern of the material during the forming of the pressure relief groove 2111 on the first bottom wall 21152, so as to improve the processing quality of the pressure relief groove 2111, and on the other hand, the structural strength of the first bottom wall 21152 is further improved, which is beneficial to alleviate the deformation of the region of the wall portion 211 provided with the pressure relief groove 2111 during use, so as to improve the use reliability and stability of the battery monomer 20.

[0170] In some embodiments, as shown in FIG. 6, the pressure relief groove 2111 is arranged around the arch portion 21152b. That is, the pressure relief groove 2111 is an annular groove structure, and the pressure relief groove 2111 surrounds the outside of the arch portion 21152b. Of course, the structure of the pressure relief groove 2111 is not limited to this, and in other embodiments, the pressure relief groove 2111 can also be an arc-shaped groove structure or a strip-shaped groove structure.

[0171] In the embodiment, by setting the pressure relief groove 2111 as a ring structure surrounding the arch portion 21152b, the first bottom wall 21152 of which the arch portion 21152b is formed can be entirely separated after the wall portion 211 is entirely cracked along the pressure relief groove 2111 when the battery monomer 20 is pressure relieved, which is conducive to expanding the pressure relief area of the battery monomer 20, thereby further improving the pressure relief rate of the battery monomer 20, so as to reduce the risk of explosion or burst of the battery monomer 20 due to untimely pressure relief, and thus the use reliability of the battery monomer 20 can be effectively improved.

[0172] In some embodiments, referring to FIGS. 5 and 6, the pressure relief groove 2111 is arranged on the side of the main body portion 21152a of the first bottom wall 21152 away from the electrode assembly 22 along the thickness direction X of the wall portion.

[0173] In the embodiment, by arranging the pressure relief groove 2111 on the side of the main body portion 21152a of the first bottom wall 21152 away from the electrode assembly 22, the pressure relief groove 2111 is formed on the groove bottom surface of the first groove 2114, thereby reducing the difficulty of forming the pressure relief groove 2111 on the main body portion 21152a of the first bottom wall 21152, which is conducive to forming the pressure relief groove 2111 while forming the first groove 2114 and the arch portion 21152b, and thus the processing efficiency of the battery monomer 20 can be improved.

[0174] In some embodiments, the pressure relief groove 2111 is stamping formed on the main body portion 21152a.

[0175] In the embodiment, by arranging the pressure relief groove 2111 as a structure stamping formed on the main body portion 21152a of the first bottom wall 21152, on the one hand, the manufacturing difficulty of the pressure relief groove 2111 can be reduced, which is conducive to improving the processing efficiency of the pressure relief groove 2111, and on the other hand, in the structure that the wall portion 211 is formed with the first groove 2114 and the first protrusion 2115, and the first bottom wall 21152 of the first protrusion 2115 is formed with the arch portion 21152b, the material flow during the stamping forming of the pressure relief groove 2111 is facilitated, which is conducive to improving the processing consistency of the pressure relief groove 2111, so as to improve the production quality of the battery monomer 20.

[0176] According to some embodiments of the present application, referring to FIGS. 4, 5 and 6, the battery monomer 20 can further include an insulating piece 24. The insulating piece 24 is arranged on the side of the wall portion 211 facing the electrode assembly 22, and the insulating piece 24 is configured to insulate and isolate the wall portion 211 and the electrode assembly 22. Along the thickness direction X of the wall portion, the side of the insulating piece 24 facing the wall portion 211 is formed with a relief portion 241 accommodating the first protrusion 2115.

[0177] The insulation piece 24 serves as an insulation partition wall portion 211 and an electrode assembly 22. The insulation piece 24 is arranged on a side of the wall portion 211 facing the electrode assembly 22, that is, the insulation piece 24 is located between the wall portion 211 and the electrode assembly 22 in the thickness direction X of the wall portion.

[0178] Exemplarily, the insulation piece 24 can be made of rubber, silica gel, plastic or the like.

[0179] The insulation piece 24 is formed with a relief portion 241 on a side facing the wall portion 211, and the relief portion 241 accommodates the first protrusion 2115. That is, the insulation piece 24 is formed with the relief portion 241 on a side facing the wall portion 211 in the thickness direction X of the wall portion, and the relief portion 241 can avoid the first protrusion 2115 of the wall portion 211, so that the first protrusion 2115 of the wall portion 211 can be accommodated in the relief portion 241 of the insulation piece 24, that is, the first protrusion 2115 of the wall portion 211 does not contact the insulation piece 24.

[0180] Optionally, the relief portion 241 can be a relief groove arranged on a side of the insulation piece 24 facing the wall portion 211, or a relief space formed on a side of the insulation piece 24 facing the wall portion 211, etc.

[0181] In this embodiment, by arranging the relief portion 241 for accommodating the first protrusion 2115 on a side of the insulation piece 24 facing the wall portion 211, the insulation piece 24 can avoid the first protrusion 2115. On the one hand, the interference between the first protrusion 2115 and the insulation piece 24 or other components can be alleviated, so as to improve the assembly quality of the battery monomer 20. On the other hand, by accommodating the first protrusion 2115 of the wall portion 211 provided with the relief groove 2111 in the relief portion 241 of the insulation piece 24, the insulation piece 24 can also protect the region of the wall portion 211 provided with the relief groove 2111, so as to reduce the wear or damage of the region of the wall portion 211 provided with the relief groove 2111 during assembly, thereby facilitating the improvement of the production quality of the battery monomer 20.

[0182] According to some embodiments of the present application, referring to FIG. 5, the insulation piece 24 can include a body portion 242 and an abutting portion 243. The body portion 242 is arranged between the wall portion 211 and the electrode assembly 22 in the thickness direction X of the wall portion. The abutting portion 243 is connected to a side of the body portion 242 facing the wall portion 211, and the abutting portion 243 abuts against the second surface 2113. In the thickness direction X of the wall portion, the projection of the abutting portion 243 does not overlap the projection of the first protrusion 2115, so as to form a spacing space between the body portion 242 and the second surface 2113, and the spacing space is the relief portion 241.

[0183] The body portion 242 is arranged between the wall portion 211 and the electrode assembly 22 along the thickness direction X of the wall portion, that is, the body portion 242 of the insulating member 24 is the part of the insulating member 24 that insulates and separates between the wall portion 211 and the electrode assembly 22.

[0184] The abutting portion 243 is connected to one side of the body portion 242 facing the wall portion 211, and the abutting portion 243 abuts against the second surface 2113, that is, the abutting portion 243 is a structure supported between the body portion 242 and the wall portion 211 along the thickness direction X of the wall portion.

[0185] Along the thickness direction X of the wall portion, the projection of the abutting portion 243 does not overlap the projection of the first protrusion 2115, so as to form a spacing space between the body portion 242 and the second surface 2113, that is, the abutting portion 243 of the insulating member 24 does not cover the first protrusion 2115 along the thickness direction X of the wall portion, so that the body portion 242 of the insulating member 24 and the second surface 2113 of the wall portion 211 are arranged apart from each other and form a spacing space, and the spacing space is the avoiding portion 241 of the insulating member 24 for avoiding the first protrusion 2115.

[0186] It should be noted that the structure of the insulating member 24 is not limited to this, and in other embodiments, the insulating member 24 can also have other structures, for example, the insulating member 24 abuts against the second surface 2113 of the wall portion 211, and the surface of the insulating member 24 abutting against the second surface 2113 is provided with an avoiding groove for accommodating the first protrusion 2115, and the avoiding groove is the avoiding portion 241 of the insulating member 24.

[0187] Optionally, the abutting portion 243 connected to one side of the body portion 242 facing the wall portion 211 can be one or multiple. Similarly, the structure of the abutting portion 243 connected to the body portion 242 can also be various, such as adhesion, clamping or hot melt connection, etc.

[0188] Optionally, the body portion 242 can also be provided with a positioning hole, the positioning hole penetrating through the body portion 242 along the thickness direction X of the wall portion, and the positioning hole plays a positioning role during the process of assembling the insulating member 24 into the shell 21, so as to reduce the difficulty of assembling the insulating member 24 into the shell 21, and improve the precision of assembling the insulating member 24 into the shell 21.

[0189] In the embodiment, the insulating member 24 is provided with the body portion 242 and the abutting portion 243 connected to the side of the body portion 242 facing the wall portion 211. By abutting the abutting portion 243 on the second surface 2113 of the wall portion 211 and the projection of the abutting portion 243 on the thickness direction X of the wall portion does not overlap with the projection of the first protrusion 2115, the abutting portion 243 is supported between the body portion 242 and the wall portion 211, so that the body portion 242 and the wall portion 211 of the insulating member 24 are arranged in a spaced manner in the thickness direction X of the wall portion, thereby forming a spacing space between the body portion 242 and the second surface 2113 of the wall portion 211 of the insulating member 24 to avoid the first protrusion 2115, and forming the avoiding portion 241 for avoiding the first protrusion 2115. The structure is simple and convenient to assemble.

[0190] In some embodiments, referring to FIG. 5, the insulating member 24 can include a plurality of abutting portions 243, and the plurality of abutting portions 243 are arranged in a spaced manner on the side of the body portion 242 facing the wall portion 211.

[0191] For example, the body portion 242 is connected to two abutting portions 243 on the side facing the wall portion 211 in the thickness direction X of the wall portion, and the two abutting portions 243 are arranged in a spaced manner in a direction perpendicular to the thickness direction X of the wall portion, and the two abutting portions 243 are respectively located on the two sides of the first protrusion 2115 in the direction perpendicular to the thickness direction X of the wall portion. Of course, in other embodiments, the insulating member 24 can also be provided with three, four, five, six or seven abutting portions 243.

[0192] In the embodiment, by connecting a plurality of abutting portions 243 to the side of the body portion 242 facing the wall portion 211 and arranging the plurality of abutting portions 243 in a spaced manner, the structural stability of the insulating member 24 assembled between the electrode assembly 22 and the wall portion 211 can be further improved, and the effect of the plurality of abutting portions 243 supporting the body portion 242 can be improved, so as to improve the overall structural strength of the insulating member 24, thereby reducing the deformation or collapse of the body portion 242 during use, and relieving the mutual interference between the body portion 242 and the first protrusion 2115 after the deformation of the body portion 242, thereby further improving the effect of the insulating member 24 avoiding the first protrusion 2115.

[0193] In some embodiments, referring to FIG. 5, along the thickness direction X of the wall portion, the minimum distance between the body portion 242 and the first protrusion 2115 is L, and L≥0.1mm.

[0194] Exemplarily, the minimum distance L between the body portion 242 and the first protrusion 2115 can be 0.1 mm, 0.12 mm, 0.13 mm, 0.15 mm, 0.18 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, or 1.5 mm, etc.

[0195] In the present embodiment, by setting the minimum distance between the body portion 242 and the first protrusion 2115 in the thickness direction X of the wall portion to be greater than or equal to 0.1 mm, the avoidance effect of the avoidance portion 241 of the insulation member 24 on the first protrusion 2115 is further improved, so as to reduce the phenomenon that the body portion 242 of the insulation member 24 interferes with or wears the first protrusion 2115, thereby further improving the assembly quality of the battery monomer 20.

[0196] According to some embodiments of the present application, referring to FIG. 7 and FIG. 8, FIG. 7 is a sectional view of the shell 21 of the battery monomer 20 provided by some embodiments of the present application, and FIG. 8 is a partial enlarged view of position A of the shell 21 shown in FIG. 7. Along the thickness direction X of the wall portion, the wall portion 211 has opposite first and second surfaces 2112 and 2113, the pressure relief groove 2111 is arranged on the first surface 2112, and the pressure relief groove 2111 is located between the first and second surfaces 2112 and 2113 in the thickness direction X of the wall portion.

[0197] In the present embodiment, by arranging the pressure relief groove 2111 on the first surface 2112 and setting the pressure relief groove 2111 to be located between the first and second surfaces 2112 and 2113 in the thickness direction X of the wall portion, the region of the second surface 2113 corresponding to the pressure relief groove 2111 is not formed with a protrusion structure, thereby facilitating the alleviation of the interference phenomenon between the region of the wall portion 211 provided with the pressure relief groove 2111 and other components, so as to improve the assembly quality of the battery monomer 20.

[0198] In the present embodiment, by arranging the pressure relief groove 2111 on the first surface 2112 and setting the pressure relief groove 2111 to be located between the first and second surfaces 2112 and 2113 in the thickness direction X of the wall portion, the region of the second surface 2113 corresponding to the pressure relief groove 2111 is not formed with a protrusion structure, thereby facilitating the alleviation of the interference phenomenon between the region of the wall portion 211 provided with the pressure relief groove 2111 and other components, so as to improve the assembly quality of the battery monomer 20.

[0199] In some embodiments, referring to FIG. 8, the first surface 2112 is parallel to the second surface 2113.

[0200] In the embodiment, by setting the first surface 2112 and the second surface 2113 as a parallel structure, interference between the region where the wall portion 211 is provided with the pressure relief groove 2111 and other components can be further alleviated, so as to further improve the assembly quality of the battery monomer 20.

[0201] In some embodiments, referring to FIGS. 7 and 8, the second surface 2113 faces the electrode assembly 22 along the thickness direction X of the wall portion. That is, the pressure relief groove 2111 is arranged on the surface of the side of the wall portion 211 away from the electrode assembly 22.

[0202] In the embodiment, by setting the second surface 2113 as a structure facing the electrode assembly 22, the pressure relief groove 2111 is arranged on the surface of the side of the wall portion 211 away from the electrode assembly 22, so as to facilitate the forming of the pressure relief groove 2111 on the wall portion 211, and reduce the difficulty of arranging the pressure relief groove 2111 on the wall portion 211, thereby improving the production efficiency of the battery monomer 20.

[0203] In some embodiments, the pressure relief groove 2111 is etched and formed on the wall portion 211.

[0204] For example, in such an embodiment, the pressure relief groove 2111 can be formed on the wall portion 211 by a laser etching process or a chemical etching process.

[0205] In the embodiment, the pressure relief groove 2111 is formed on the wall portion 211 by etching, so as to be located between the first surface 2112 and the second surface 2113 of the wall portion 211 along the thickness direction X of the wall portion, thereby facilitating the realization that the second surface 2113 does not form a protruding structure corresponding to the region of the pressure relief groove 2111, and reducing the processing difficulty of the pressure relief groove 2111 on the wall portion 211.

[0206] According to some embodiments of the present application, referring to FIGS. 3 and 4, the pressure relief groove 2111 is an annular groove. That is, the pressure relief groove 2111 is an annular structure connected at the head and tail.

[0207] For example, in FIG. 3, the pressure relief groove 2111 is in an elliptical shape, and of course, in other embodiments, the pressure relief groove 2111 can also be in a circular shape or the like.

[0208] In the embodiment, by setting the pressure relief groove 2111 as a ring groove structure, the wall portion 211 can be entirely separated after the wall portion 211 is entirely cracked along the pressure relief groove 2111 when the battery monomer 20 is pressure relieved, the region of the wall portion 211 inside the pressure relief groove 2111 is entirely separated, which is beneficial to expand the pressure relief area of the battery monomer 20, so as to further improve the pressure relief rate of the battery monomer 20, so as to reduce the risk of explosion or burst of the battery monomer 20 due to untimely pressure relief, and thus the use reliability of the battery monomer 20 can be effectively improved.

[0209] According to some embodiments of the present application, as shown in FIGS. 3 and 4, the shell 21 can include a shell body 212 and two end covers 213. The shell body 212 has an accommodating cavity formed inside, and the electrode assembly 22 is accommodated in the accommodating cavity. Opposite ends of the shell body 212 are both formed with openings 2121, and the two openings 2121 are both in communication with the accommodating cavity. The two end covers 213 respectively close the two openings 2121, and the shell body 212 includes the wall portion 211.

[0210] The shell body 212 includes the wall portion 211, that is, the wall portion 211 is one of the plurality of walls of the shell body 212, and correspondingly, the pressure relief groove 2111 is arranged on one wall of the shell body 212.

[0211] In the embodiment, the shell body 212 of the shell 21 is arranged with the openings 2121 on the opposite ends, and the two end covers 213 respectively close the two openings 2121. By arranging the wall portion 211 of the shell 21 as one wall of the shell body 212, the battery monomer 20 with this structure can make the region of the shell 21 provided with the pressure relief groove 2111 away from the end cover 213, so as to effectively alleviate the phenomenon that the stress generated by the mutual connection of the end cover 213 and the shell body 212 acts on the region of the wall portion 211 provided with the pressure relief groove 2111, so as to reduce the influence on the region of the wall portion 211 provided with the pressure relief groove 2111, and thus it is beneficial to reduce the risk of cracking or structural strength reduction of the region of the wall portion 211 provided with the pressure relief groove 2111 under the pulling action of the stress, so as to improve the service life and use reliability of the battery monomer 20.

[0212] Of course, the structure of the battery monomer 20 is not limited to this. In other embodiments, the battery monomer 20 can also have other structures. For example, the shell 21 can include a shell body 212 and two end covers 213. The shell body 212 has an accommodating cavity formed inside, and the electrode assembly 22 is accommodated in the accommodating cavity. Opposite ends of the shell body 212 are both formed with openings 2121, and the two openings 2121 are both in communication with the accommodating cavity. The two end covers 213 respectively close the two openings 2121, and one of the two end covers 213 is the wall portion 211.

[0213] In the embodiment, by setting the wall portion 211 as one of the end covers 213, the battery monomer 20 adopting the structure is convenient for assembling the battery monomer 20 from both ends of the shell 212 respectively, which is conducive to reducing the manufacturing difficulty and assembly difficulty of the battery monomer 20, and is convenient for setting the pressure relief groove 2111 on the end cover 213, which is conducive to reducing the manufacturing difficulty of the battery monomer 20, so as to improve the production efficiency of the battery monomer 20.

[0214] It should be noted that the structure of the battery monomer 20 can also be various. In some embodiments, the shell 21 can include a shell 212 and an end cover 213. The shell 212 has an accommodating cavity with an opening 2121 formed inside. The electrode assembly 22 is accommodated in the accommodating cavity. The end cover 213 closes the opening 2121. The shell 212 includes a wall portion 211. That is, the shell 212 of the shell 21 is a hollow structure with an opening 2121 formed at only one end.

[0215] The shell 212 includes an integrally formed second side wall and a second bottom wall. That is, the shell 212 is processed by an integral forming process, such as stamping, casting or extrusion forming.

[0216] The shell 212 includes a wall portion 211. That is, the wall portion 211 is a wall of the shell 212. The wall portion 211 can be a second bottom wall of the shell 212 arranged opposite to the end cover 213 in the thickness direction X of the wall portion, or a second side wall of the shell 212.

[0217] In the embodiment, by setting the wall portion 211 of the shell 21 as a wall of the shell 212, the battery monomer 20 adopting the structure can make the region of the shell 21 where the pressure relief groove 2111 is arranged away from the end cover 213, so as to effectively alleviate the phenomenon that the stress generated by the mutual connection of the end cover 213 and the shell 212 acts on the region of the wall portion 211 where the pressure relief groove 2111 is arranged, so as to reduce the influence on the region of the wall portion 211 where the pressure relief groove 2111 is arranged, and further conducive to reducing the risk of cracking or structural strength reduction of the region of the wall portion 211 where the pressure relief groove 2111 is arranged under the pulling action of the stress, so as to improve the service life and use reliability of the battery monomer 20.

[0218] Of course, the structure of the battery monomer 20 is not limited to this. In the embodiment in which the shell 21 can include a shell 212 and an end cover 213, the end cover 213 can also be the wall portion 211. By setting the wall portion 211 of the shell 21 as the end cover 213 of the shell 21 for closing the opening 2121, the battery monomer 20 adopting the structure is convenient for setting the pressure relief groove 2111 on the end cover 213, which is conducive to reducing the manufacturing difficulty of the battery monomer 20, so as to improve the production efficiency of the battery monomer 20.

[0219] According to some embodiments of the present application, the present application also provides a battery 100, which comprises the battery cell 20 of any of the above solutions.

[0220] As shown in FIG. 2, the battery 100 can further comprise a box 10, and the battery cell 20 is accommodated in the box 10.

[0221] In some embodiments, the box 10 can comprise a first box body 11 and a second box body 12, the first box body 11 and the second box body 12 are mutually coverable, and the first box body 11 and the second box body 12 jointly define an assembly space for accommodating the battery cell 20.

[0222] Optionally, the second box body 12 can be a hollow structure with one end open, and the first box body 11 can be a plate structure, the first box body 11 is coverable on the open side of the second box body 12, so that the first box body 11 and the second box body 12 jointly define the assembly space; the first box body 11 and the second box body 12 can also be hollow structures with one side open, and the open side of the first box body 11 is coverable on the open side of the second box body 12.

[0223] Of course, the box 10 formed by the first box body 11 and the second box body 12 can be various shapes, such as a cylinder or a cuboid, etc. Exemplarily, in FIG. 2, the box 10 is a cuboid structure.

[0224] Optionally, the battery cell 20 arranged in the box 10 can be one or multiple. Exemplarily, in FIG. 2, multiple battery cells 20 are arranged in the box 10 of the battery 100, and the multiple battery cells 20 can be in series connection, parallel connection or mixed connection, and the mixed connection means that the multiple battery cells 20 are in both series connection and parallel connection. The multiple battery cells 20 can be directly connected in series, parallel or mixed connection, and then the whole of the multiple battery cells 20 is accommodated in the box 10; of course, the battery 100 can also be that the multiple battery cells 20 are first connected in series, parallel or mixed connection to form a battery module, and then multiple battery modules are connected in series, parallel or mixed connection to form a whole, and the whole is accommodated in the box 10.

[0225] The battery 100 can further comprise other structures, for example, the battery 100 can further comprise a current collecting component, and the current collecting component is connected to the multiple battery cells 20 to realize electrical connection between the multiple battery cells 20.

[0226] It should be noted that in some embodiments, the battery 100 can also not be provided with the box 10, the battery 100 includes a plurality of battery monomers 20, and the battery 100 composed of a plurality of battery monomers 20 can be directly assembled to the electric device to provide electric energy for the electric device by the plurality of battery monomers 20. That is, the box 10 can be part of the electric device. Taking the vehicle 1000 as an example of the electric device, the box 10 can be part of the chassis structure of the vehicle 1000, for example, part of the box 10 can become at least part of the floor of the vehicle 1000, or part of the box 10 can become at least part of the cross beam and the longitudinal beam of the vehicle 1000.

[0227] According to some embodiments of the present application, the present application also provides an electric device, the electric device includes the battery monomer 20 of any one of the above schemes, and the battery monomer 20 is used to provide electric energy for the electric device.

[0228] Among them, the electric device can be any one of the above application devices or systems using the battery monomer 20.

[0229] According to some embodiments of the present application, referring to FIGS. 3-6, the present application provides a battery cell 20, which comprises a shell 21, an electrode assembly 22 and an insulation piece 24. The shell 21 has a wall portion 211, which comprises a shell body 212 and two end covers 213. The shell body 212 has an accommodating cavity formed inside, and opposite ends of the shell body 212 are each formed with an opening 2121, which is in communication with the accommodating cavity. The two end covers 213 are respectively arranged to close the two openings 2121. The shell body 212 comprises the wall portion 211. The electrode assembly 22 is accommodated in the accommodating cavity. The shell 21 is made of steel, and the wall portion 211 is provided with a pressure relief groove 2111. The wall portion 211 is configured to be split along at least part of the pressure relief groove 2111 to release the internal pressure of the battery cell 20 when the battery cell 20 is relieved of pressure. The wall thickness of the wall portion 211 is D1, and the minimum residual thickness of the pressure relief groove 2111 is D2, which satisfy 0.075mm≤D1≤0.4mm and 0.08≤D2 / D1≤0.3. Along the thickness direction X of the wall portion, the wall portion 211 has opposite first and second surfaces 2112 and 2113. The second surface 2113 faces the electrode assembly 22. The first surface 2112 is provided with a first groove 2114. The wall portion 211 is provided with a first protrusion 2115 protruding from the second surface 2113 at a position corresponding to the first groove 2114. The first protrusion 2115 comprises a first side wall 21151 and a first bottom wall 21152. The first side wall 21151 surrounds the first bottom wall 21152 and is connected to the first bottom wall 21152. The first side wall 21151 and the first bottom wall 21152 jointly define the first groove 2114. The first bottom wall 21152 comprises a main body portion 21152a and an arch portion 21152b. The main body portion 21152a connects the arch portion 21152b and the first side wall 21151. The main body portion 21152a surrounds the outside of the arch portion 21152b. Along the thickness direction X of the wall portion, the arch portion 21152b arches away from the main body portion 21152a to form a second groove 21152c on the side of the first bottom wall 21152 facing the electrode assembly 22 and corresponding to the arch portion 21152b. The pressure relief groove 2111 is arranged on the side of the main body portion 21152a away from the electrode assembly 22. The pressure relief groove 2111 surrounds the arch portion 21152b and is stamped and formed on the main body portion 21152a. The insulation piece 24 is arranged on the side of the wall portion 211 facing the electrode assembly 22. The insulation piece 24 is configured to insulate and isolate the wall portion 211 and the electrode assembly 22. Along the thickness direction X of the wall portion, the insulation piece 24 is formed with a relief portion 241 on the side facing the wall portion 211, which accommodates the first protrusion 2115.The insulation piece 24 includes a body portion 242 and two abutting portions 243, the body portion 242 is arranged between the wall portion 211 and the electrode assembly 22 along the thickness direction X of the wall portion, the two abutting portions 243 are both connected to one side of the body portion 242 facing the wall portion 211, and the abutting portion 243 abuts against the second surface 2113, along the thickness direction X of the wall portion, the projection of the abutting portion 243 does not overlap with the projection of the first protrusion 2115, so as to form a spacing space between the body portion 242 and the second surface 2113, the spacing space is the avoiding portion 241, and the minimum distance between the body portion 242 and the first protrusion 2115 is L, which satisfies L≥0.1mm.

[0230] According to some embodiments of the present application, referring to FIGS. 7-8, the present application provides a battery monomer 20, which includes a shell 21, an electrode assembly 22 and an insulation piece 24. The shell 21 has a wall portion 211, and the shell 21 includes a shell body 212 and two end covers 213, the shell body 212 has an accommodating cavity formed inside, opposite ends of the shell body 212 are both formed with an opening 2121, and the two openings 2121 are both in communication with the accommodating cavity, and the two end covers 213 respectively close the two openings 2121, and the shell body 212 includes the wall portion 211. The electrode assembly 22 is accommodated in the accommodating cavity. The material of the shell 21 is steel, and the wall portion 211 is provided with a pressure relief groove 2111, the pressure relief groove 2111 is etched and formed on the wall portion 211, and the wall portion 211 is configured to be able to split along at least part of the pressure relief groove 2111 when the battery monomer 20 is relieved, so as to release the internal pressure of the battery monomer 20, and the pressure relief groove 2111 is an annular groove. The wall thickness of the wall portion 211 is D1, the minimum residual thickness of the pressure relief groove 2111 is D2, and 0.075mm≤D1≤0.4mm and 0.08≤D2 / D1≤0.3 are satisfied. Along the thickness direction X of the wall portion, the wall portion 211 has opposite first and second surfaces 2112 and 2113, the second surface 2113 is arranged to face the electrode assembly 22, the pressure relief groove 2111 is arranged on the first surface 2112, and the pressure relief groove 2111 is located between the first and second surfaces 2112 and 2113 along the thickness direction X of the wall portion, and the first and second surfaces 2112 and 2113 are parallel.

[0231] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0232] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Various modifications and changes can be made by those skilled in the art based on the spirit and principles of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A single battery cell, comprising: The outer shell has walls; as well as Electrode assembly, housed within the housing; The outer casing is made of steel, and the wall is provided with a pressure relief groove. The wall is configured to crack along at least a portion of the pressure relief groove when the battery cell is depressurized, so as to release the internal pressure of the battery cell.

2. The battery cell according to claim 1, wherein, The wall thickness of the wall portion is D1, which satisfies the condition 0.075mm≤D1≤0.4mm.

3. The battery cell according to claim 2, wherein, 0.075mm≤D1≤0.25mm.

4. The battery cell according to any one of claims 1-3, wherein, Along the thickness direction of the wall portion, the minimum residual thickness of the pressure relief groove is D2, and the wall thickness of the wall portion is D1, satisfying 0.08≤D2 / D1≤0.

3.

5. The battery cell according to any one of claims 1-4, wherein, Along the thickness direction of the wall portion, the wall portion has a first surface and a second surface opposite to each other, the second surface is disposed facing the electrode assembly, the first surface is provided with a first groove, and the wall portion has a first protrusion protruding from the second surface at a position corresponding to the first groove, and the pressure relief groove is disposed on the first protrusion.

6. The battery cell according to claim 5, wherein, The first protrusion includes a first sidewall and a first bottom wall. The first sidewall surrounds the first bottom wall and is connected to the first bottom wall. The first sidewall and the first bottom wall together define the first groove. The pressure relief groove is disposed on the first bottom wall.

7. The battery cell according to claim 6, wherein, The first bottom wall includes a main body and an arched portion, the main body connecting the arched portion and the first side wall, and the main body surrounding the outside of the arched portion; Along the thickness direction of the wall portion, the arched portion arches from the main body portion toward the direction away from the electrode assembly, so as to form a second groove on the side of the first bottom wall facing the electrode assembly and corresponding to the position of the arched portion, and the pressure relief groove is provided in the main body portion.

8. The battery cell according to claim 7, wherein, The pressure relief groove is arranged around the arched portion.

9. The battery cell according to claim 7 or 8, wherein, Along the thickness direction of the wall portion, the pressure relief groove is disposed on the side of the main body portion away from the electrode assembly.

10. The battery cell according to any one of claims 7-9, wherein, The pressure relief groove is formed by stamping on the main body.

11. The battery cell according to any one of claims 5-10, wherein, The battery cell also includes: An insulating element is disposed on the side of the wall portion facing the electrode assembly, the insulating element being configured to insulatingly isolate the wall portion and the electrode assembly; Along the thickness direction of the wall portion, the insulating member has a clearance portion formed on the side facing the wall portion, and the clearance portion accommodates the first protrusion.

12. The battery cell according to claim 11, wherein, The insulating component includes: The body portion is disposed between the wall portion and the electrode assembly along the thickness direction of the wall portion; An abutting portion is connected to the side of the body portion facing the wall portion, and the abutting portion abuts against the second surface; Wherein, along the thickness direction of the wall portion, the projection of the abutment portion does not overlap with the projection of the first protrusion, so as to form a gap space between the body portion and the second surface, the gap space being the clearance portion.

13. The battery cell according to claim 12, wherein, The insulating member includes a plurality of abutting portions, each of which is connected to the side of the body portion facing the wall portion, and the plurality of abutting portions are spaced apart.

14. The battery cell according to claim 12 or 13, wherein, Along the thickness direction of the wall portion, the minimum distance between the body portion and the first protrusion is L, which satisfies L≥0.1mm.

15. The battery cell according to any one of claims 1-4, wherein, Along the thickness direction of the wall portion, the wall portion has opposing first and second surfaces; The pressure relief groove is disposed on the first surface, and the pressure relief groove is located between the first surface and the second surface in the thickness direction of the wall portion.

16. The battery cell according to claim 15, wherein, The first surface is parallel to the second surface.

17. The battery cell according to claim 15 or 16, wherein, The second surface is disposed facing the electrode assembly along the thickness direction of the wall portion.

18. The battery cell according to any one of claims 15-17, wherein, The pressure relief groove is etched into the wall portion.

19. The battery cell according to any one of claims 1-18, wherein, The pressure relief groove is an annular groove.

20. The battery cell according to any one of claims 1-19, wherein, The outer casing includes: The housing has an internal cavity for receiving the electrode assembly, and openings are formed at opposite ends of the housing, with both openings communicating with the cavity. Two end caps, respectively sealing the two openings; Wherein, the housing includes the wall portion; or One of the two end caps is the wall portion.

21. The battery cell according to any one of claims 1-19, wherein, The outer casing includes: The housing has an internally formed receiving cavity with an opening, and the electrode assembly is received within the receiving cavity; End cap, to close the opening; Wherein, the housing includes the wall portion; or The end cap is the wall portion.

22. A battery comprising a battery cell as described in any one of claims 1-21.

23. An electrical device comprising a battery cell as claimed in any one of claims 1-21, the battery cell being used to provide electrical energy.

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