Battery monomer, preparation method of battery monomer, battery and power utilization device

Abstract

The invention discloses a battery monomer, a preparation method of the battery monomer, a battery and a power utilization device, and the battery monomer comprises a pole shell which comprises a first wall; the pole is arranged on the first wall and is provided with a through hole; the cover plate is arranged on one side of the pole and covers one end corresponding to the through hole; the electrode assembly comprises an active substance coating part and a conductive part connected with the active substance coating part, the active substance coating part is arranged in the shell, and at least part of the conductive part is arranged in the through hole and connected with the cover plate. According to the battery monomer disclosed by the invention, at least part of the conductive part is arranged in the through hole, so that the occupied space of the conductive part in the shell can be reduced, the weight of the pole can be reduced, the volume energy density and the weight energy density of the battery monomer can be further improved, and meanwhile, the redundancy of the conductive part in the shell can be reduced; the probability of short circuit between the conductive part and the active material coating part is reduced, the probability of short circuit of the single battery is reduced, and the reliability of the battery is improved.

Description

Technical Field

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

[0002] With the increasingly serious environmental problems, the gradual maturity of people's environmental awareness and the rise in oil prices, more and more people will focus on new energy vehicles when purchasing vehicles, and the advantages and disadvantages of new energy vehicles in terms of endurance and power performance have a relatively important impact on people's choices. At present, most new energy vehicles use power batteries as energy storage and kinetic energy devices, and there are also traces of power batteries in other types of vehicles. The battery energy density of power batteries has a relatively important impact on the vehicle's endurance and power performance. Therefore, improving the energy density of batteries is a direction that needs to be studied in the process of continuous improvement and innovation of batteries.

[0003] At present, the energy density of batteries still needs to be improved. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention is to provide a battery cell, which can improve the volume energy density and weight energy density of the battery cell, and can also reduce the probability of short circuit of the battery cell, and improve the working reliability and stability of the battery cell and the battery.

[0005] The invention also provides a method for preparing a battery monomer.

[0006] The present invention also provides a battery having the battery cell.

[0007] The invention also provides an electrical device having the battery.

[0008] A battery cell according to a first aspect of the present invention comprises: a shell including a first wall; a pole arranged on the first wall and having a through hole; a cover plate arranged on one side of the pole and covering an end corresponding to the through hole; an electrode assembly comprising an active material coating portion and a conductive portion connected to the active material coating portion, the active material coating portion being arranged in the shell, and at least a portion of the conductive portion being arranged in the through hole and connected to the cover plate.

[0009] According to the battery cell of the present invention, by providing the pole with a through hole, and at least part of the conductive part is provided in the through hole, the space occupied by the conductive part inside the shell can be reduced, so that the housing cavity of the shell can accommodate a larger active material coating part, thereby improving the volume energy density of the battery cell. At the same time, the redundancy of the conductive part in the shell can be reduced, the probability of short circuit between the conductive part and the active material coating part can be reduced, the probability of short circuit of the battery cell can be reduced, and the working reliability and stability of the battery cell and the battery can be improved. In addition, by providing a through hole inside the pole, the weight of the pole can be reduced, thereby improving the weight energy density of the battery cell and the battery.

[0010] In some embodiments, the cover plate is connected to the conductive part by welding.

[0011] In this embodiment, by arranging the cover plate and the conductive part to be connected by welding, the connection strength and connection stability between the cover plate and the conductive part can be increased, thereby improving the stability of the electrical connection between the conductive part and the pole; at the same time, the connection complexity between the cover plate and the conductive part can be reduced, thereby reducing the production cost and overall weight of the battery cell.

[0012] In some embodiments, the cover plate has a first welding area and a second welding area, the first welding area is welded to the conductive part, the second welding area is used to weld the electrical connection sheet, and the first welding area and the second welding area are different areas of the cover plate.

[0013] By setting the first welding area and the second welding area, this embodiment can respectively limit the welding positions of the conductive part and the electrical connecting piece, thereby increasing the convenience and reliability of battery cell assembly; at the same time, by setting the first welding area and the second welding area as different areas of the cover plate, it can also effectively prevent the problem of reduced welding quality caused by the connection of two welding pools, thereby improving the welding quality of the conductive part and the electrical connecting piece with the cover plate, thereby improving the electrical connection stability of the battery cell.

[0014] In some embodiments, the first welding area and the second welding area are respectively formed on two sides of a center line of the cover plate that is perpendicular to the length direction or the width direction.

[0015] In this embodiment, the first welding area and the second welding area are respectively formed on both sides of the center line of the cover plate perpendicular to the length direction or the width direction. The first welding area and the second welding area are respectively formed on both sides of the center line of the cover plate perpendicular to the length direction or the width direction. This can facilitate further limiting the positions of the first welding area and the second welding area, thereby increasing the convenience and reliability of battery cell assembly.

[0016] In some embodiments, the spacing between the first welding area and the second welding area is less than or equal to two-thirds of the width of the cover plate, and / or the spacing between the first welding area and the second welding area is greater than or equal to one-third of the width of the cover plate.

[0017] In this embodiment, the spacing between the first welding area and the second welding area is set to be less than or equal to two-thirds of the width of the cover plate, so that the spacing between the first welding area and the second welding area is not too large, which is beneficial to ensuring the welding area of ​​the first welding area and the second welding area on the cover plate, so as to facilitate the connection of the conductive part and the electrical connecting piece with the cover plate, and ensure the welding quality of the conductive part and the electrical connecting piece with the cover plate, thereby improving the electrical connection stability of the battery cell; at the same time, by setting the spacing between the first welding area and the second welding area to be greater than or equal to one-third of the width of the cover plate, so that the spacing between the first welding area and the second welding area is not too small, the problem of reduced welding quality caused by the connection of two welding molten pools can be effectively prevented, and then the welding quality of the conductive part and the electrical connecting piece with the cover plate can be improved, thereby improving the electrical connection stability of the battery cell.

[0018] In some embodiments, a distance between the first welding area and the second welding area is greater than or equal to 2 mm.

[0019] By setting the spacing between the first welding area and the second welding area to be greater than or equal to 2 mm, this embodiment can effectively prevent the problem of reduced welding quality caused by the connection of two welding pools, thereby improving the welding quality of the conductive part and the electrical connecting piece and the cover plate, thereby improving the electrical connection stability of the battery cell.

[0020] In some embodiments, the first welding area is welded with the conductive portion to form a first welding pool, the second welding area is welded with the electrical connection sheet to form a second welding pool, and the first welding pool and the second welding pool are spaced apart.

[0021] This embodiment can effectively solve the problem of the first welding pool and the second welding pool being connected by setting the first welding pool and the second welding pool apart, thereby improving the welding quality of the conductive part and the electrical connecting piece and the cover plate, thereby improving the electrical connection stability of the battery cell.

[0022] In some embodiments, the ratio of the thickness of the cover plate to the thickness of the first wall is 1-4; optionally, the ratio of the thickness of the cover plate to the thickness of the first wall is 2-3; optionally, the thickness of the cover plate is greater than or equal to 1.5 mm and less than or equal to 5 mm.

[0023] In this embodiment, by setting the ratio of the thickness of the cover plate to the thickness of the first wall to 1-4, the thickness of the cover plate can meet the welding requirements of the conductive part and the electrical connecting piece, while not being too thick, which is beneficial to the lightweight of the battery cell.

[0024] This embodiment sets the ratio of the thickness of the cover plate to the thickness of the first wall to 2-3, which can further limit the thickness of the cover plate so that the thickness of the cover plate is not too large, which is beneficial to the lightweight of the battery cell; at the same time, it also ensures that the thickness of the cover plate is not too small, so that it can meet the welding requirements of the conductive part and the electrical connecting piece and the structural strength requirements of the battery cell.

[0025] In this embodiment, by setting the thickness of the cover plate to be greater than or equal to 1.5 mm and less than or equal to 5 mm, the thickness of the cover plate can be controlled not to be too large while meeting the welding requirements of the conductive part and the electrical connecting piece, thereby reducing the occupation of the internal space of the through hole by the cover plate, thereby improving the space utilization of the battery cell.

[0026] In some embodiments, the cover plate includes a cover plate body and a boss, the cover plate body covers one end of the through hole, the boss is arranged on a side surface of the cover plate body facing the electrode assembly and extends into the through hole, and the conductive part is connected to the boss.

[0027] By providing the cover plate body and the boss, this embodiment can increase the sealing effect between the cover plate and the pole, further reduce the risk of electrolyte leakage from the through hole, and improve the reliability of the battery cell; at the same time, it can also further reduce the occurrence of molten pool connection during welding, and then further improve the welding quality of the conductive part and the electrical connecting piece and the cover plate, thereby improving the electrical connection stability of the battery cell.

[0028] In some embodiments, the height of the boss protruding from the one side surface of the cover body is 1 mm-5 mm; optionally, 1.5 mm-3 mm.

[0029] In this embodiment, the height of the boss protruding from the surface of one side of the cover plate body is set to 1mm-5mm, so that the thickness of the boss will not be too large, which is beneficial to reducing the occupation of the internal space of the through hole by the cover plate, thereby improving the space utilization rate of the battery cell; it also ensures that the thickness of the boss is not too small, so that the thickness of the boss can meet the welding requirements of the conductive part, thereby increasing the connection stability between the conductive part and the boss.

[0030] In this embodiment, the height of the boss protruding from the surface of one side of the cover plate body is set to 1.5mm-3mm, so that the thickness of the boss can meet the welding requirements of the conductive part, and the occupation of the internal space of the through hole by the cover plate can be further reduced, thereby further improving the space utilization rate of the battery cell.

[0031] In some embodiments, the boss is clearance-matched with the one end of the through hole, and the clearance between the boss and the through hole is 0-0.1 mm.

[0032] In this embodiment, a clearance fit is provided between the boss and one end of the through hole, and the clearance between the boss and the through hole is 0-0.1 mm, which is conducive to the boss entering and exiting the through hole, thereby reducing the difficulty of assembling the cover plate and the pole.

[0033] In some embodiments, the fitting clearance between the boss and the through hole is less than or equal to 0.05 mm.

[0034] By setting the matching clearance between the boss and the through hole to be less than or equal to 0.05 mm, this embodiment can further reduce the clearance between the boss and the inner wall of the through hole, thereby further improving the blocking effect of the boss on the through hole, reducing the risk of electrolyte leakage from the cover plate, and thus improving the reliability of the battery cell.

[0035] In some embodiments, the pole is a negative pole, the cover plate body and the boss are separate parts, the cover plate body and the boss are made of different materials, the material of the boss is the same as the material of the conductive part, and when the boss is welded to the conductive part, the depth of the molten pool on the cover plate is less than the thickness of the boss.

[0036] In this embodiment, the pole is a negative pole, and the cover plate body and the boss are separate parts, and the material of the boss is the same as the material of the conductive part. In this way, the material of the boss can be adapted to the material of the conductive part, thereby increasing the welding quality of the boss and the conductive part, and increasing the connection stability of the boss and the conductive part. In addition, when the boss and the conductive part are welded, the molten pool depth on the cover plate is less than the thickness of the boss, and the welding position is controlled between the same materials. In this way, the welding quality of the boss and the conductive part can be further increased, and the welding difficulty of the boss and the conductive part can be reduced.

[0037] In some embodiments, the pole is a positive pole, the boss and the cover plate body are integrally formed, and when the cover plate and the conductive part are welded, the depth of the molten pool on the boss is greater than the thickness of the boss.

[0038] In this embodiment, when the pole is a positive pole, the boss is formed integrally with the cover plate body so that the cover plate meets the welding requirements with the electrical connecting piece and the conductive part, and the production process of the cover plate is reduced, the production steps of the cover plate are reduced, and the production rate of the cover plate is increased, and the production cost of the cover plate is reduced.

[0039] In some embodiments, the pole is connected to the cover plate by welding.

[0040] In this embodiment, by arranging the electrode column and the cover plate to be welded, the connection stability and sealing performance between the electrode column and the cover plate can be increased, thereby improving the airtightness of the battery cell, thereby improving the reliability of the battery cell.

[0041] In some embodiments, the pole is hollow and annular and defines the through hole inside.

[0042] In this embodiment, the pole is configured as a hollow ring and a through hole is defined on the inner side, so that the weight of the pole can be reduced to a certain extent, thereby improving the weight energy density of the battery cell and the battery; at the same time, the hollow ring has a large internal cavity volume, so that the conductive part can be easily extended out of the through hole, thereby reducing the difficulty of welding the conductive part and the cover plate, reducing the difficulty of assembling the battery cell, and improving the assembly rate of the battery cell.

[0043] In some embodiments, the pole includes: a pole body, which is annular and defines the through hole on the inner side; a first ring, which is connected to one end of the pole body facing the electrode assembly, and extends radially outward from the pole body and extends circumferentially from the pole body to form a ring; and a second ring, which is connected to the other end of the pole body away from the electrode assembly, and extends radially outward from the pole body and extends circumferentially from the pole body to form a ring.

[0044] In this embodiment, the first ring and the second ring are respectively arranged at both ends of the pole body. The first ring and the second ring can improve the structural strength of the pole body to a certain extent, so that the overall structural strength of the pole is better, so that the pole and the pole ear are more stable and reliable when connected and fixed, and the pole can better participate in the power transmission operation of the battery cell. The first ring and the second ring can cooperate with the pole body to form a slot structure, so as to facilitate the installation and fixation of the pole in the battery cell. The first ring and the second ring have a simple structure and are easy to use.

[0045] In some embodiments, a groove is formed on a surface of the pole facing away from the electrode assembly, the through hole is formed on the inner side of the groove and passes through the bottom wall of the groove, and the cover plate is disposed in the groove.

[0046] In this embodiment, a groove is formed on the surface of the pole facing away from the electrode assembly, so that the cover plate and the pole can be positioned more conveniently when fixed, and the connection and fixation are more stable and reliable.

[0047] In some embodiments, in a direction from the electrode assembly toward the cover plate, a sidewall of the groove extends obliquely outward along a radial direction of the through hole.

[0048] In this embodiment, by setting the side wall of the groove to extend outwardly along the radial direction of the through hole, it can play a certain guiding role when assembling the cover plate and the pole, so that the cover plate can be more conveniently fixed in the groove, with a simple structure and easy assembly. At the same time, when the cover plate and the pole are welded, the peripheral edge of the cover plate and the inclined side wall of the groove can also increase the welding width during welding, so that the cover plate and the pole have a higher welding quality, thereby increasing the welding sealing effect between the cover plate and the pole, and increasing the sealing of the battery cell.

[0049] In some embodiments, a surface of one side of the cover plate facing away from the electrode assembly is flush with an end surface of one end of the pole facing away from the electrode assembly.

[0050] In this embodiment, by setting the surface of one side of the cover plate facing away from the electrode assembly to be flush with the end face of the pole facing away from the electrode assembly, the cover plate and the pole can cooperate to form a continuous plane, thereby reducing the space occupied by the cover plate to a certain extent and increasing the electrical connection surface of the battery cell pole, so that the energy density of the battery cell can be improved to a certain extent, and the battery cell can be more conveniently electrically connected to the electrical connector through the end of the pole facing away from the electrode assembly; at the same time, the appearance of the battery cell can also be improved.

[0051] In some embodiments, the active material coating portion includes a current collector and an active material layer disposed on the current collector, the conductive portion includes a pole ear portion electrically connected to the current collector, the pole ear portion includes a plurality of pole ear sheets, a plurality of the pole ear sheets converge at a position close to the current collector to form a first gathered portion, a plurality of the pole ear sheets converge at a position away from the current collector and are connected to form a second gathered portion, the first gathered portion connects the second gathered portion and the active material coating portion, and at least a portion of the second gathered portion is accommodated in the through hole.

[0052] In this embodiment, a plurality of pole tabs are arranged to converge and connect to form a second gathered portion, so that the second gathered portion can have a smaller size and thickness, so that the pole tab portion can be more easily and conveniently inserted into the through hole and connected to the cover plate, thereby increasing the convenience of connecting the conductive portion and the cover plate, and at the same time, it can also effectively reduce the risk of short circuit with the active material coating portion under the pole tab portion due to the inverted insertion of the pole tab portion caused by the bifurcation of multiple pole tabs, thereby improving the reliability of the battery cell. In addition, at least part of the second gathered portion is arranged to be accommodated in the through hole, which can also make full use of the space of the pole column and improve the volume energy density of the battery cell.

[0053] In some embodiments, the conductive portion is fixedly connected to the cover plate via the second retracted portion.

[0054] In this embodiment, the conductive portion is fixedly connected to the cover plate through the second folded portion, which can simplify the structure of the battery cell, reduce the use of parts, simplify the assembly process, and improve assembly efficiency.

[0055] In some embodiments, at least a portion of the first gathering portion is accommodated in the through hole.

[0056] By arranging that at least a portion of the first folded portion is accommodated in the through hole, this embodiment can make more effective use of the space in the pole column, further reduce the space occupied by the pole ear portion in the shell, so as to accommodate a larger active material coating portion, thereby improving the volume energy density of the battery cell, and better reducing the redundancy of the pole ear portion in the shell, further reducing the probability of short circuit between the pole ear portion and the active material coating portion.

[0057] In some embodiments, the active material coating portion includes a current collector and an active material layer disposed on the current collector, the conductive portion includes a pole ear portion electrically connected to the current collector, the pole ear portion includes a plurality of pole ear sheets, a plurality of the pole ear sheets converge at a position close to the current collector to form a first gathered portion, a plurality of the pole ear sheets converge at a position away from the current collector and are connected to form a second gathered portion, the first gathered portion connects the second gathered portion and the active material coating portion; the conductive portion also includes a transfer sheet, the transfer sheet is connected to the second gathered portion, the conductive portion is electrically connected to the cover plate through the transfer sheet, and at least a portion of the transfer sheet is accommodated in the through hole.

[0058] By providing the adapter sheet, the present embodiment can accommodate at least part of the second folded portion and at least part of the adapter sheet in the through hole, so that the space in the pole can be more fully utilized, and the space occupied by the conductive part in the housing can be further reduced to improve the volume energy density of the battery cell. At the same time, the adapter sheet can be used to avoid the second folded portion and welded to the pole, so that the welding between the adapter sheet and the pole is more reliable, the risk of welding cracking is small, and the reliability and stability of the battery cell can be further improved; at the same time, the pole and the pole tab sheet are electrically connected through the adapter sheet, which can also simplify the structure of the pole tab sheet.

[0059] In some embodiments, at least a portion of the second gathering portion is located in the through hole; or, the entire second gathering portion is located in the through hole, and at least a portion of the first gathering portion is located in the through hole.

[0060] In this embodiment, by arranging that at least a part of the second gathering portion is located in the through hole, the space in the pole column can be fully utilized, and the space occupied by the pole ear portion in the shell can be further reduced, so as to improve the volume energy density of the battery cell; by arranging that the second gathering portion is entirely located in the through hole and at least a part of the first gathering portion is located in the through hole, the space in the pole column can be more fully utilized, and the space occupied by the pole ear portion in the shell can be greatly reduced, thereby greatly improving the volume energy density of the battery cell; at the same time, the redundancy of the pole ear portion in the shell can be further reduced, and the probability of short circuit between the pole ear portion and the active material coating portion can be further reduced.

[0061] In some embodiments, the second gathering portion extends along the surface of the cover plate, and in the direction from the electrode assembly toward the cover plate, one end of the first gathering portion is connected to the active material coating portion, and the other end of the first gathering portion extends obliquely toward the peripheral wall of the through hole and extends to be connected to one end of the second gathering portion.

[0062] In this embodiment, a second gathering portion is arranged to extend along the surface of the cover plate. In the direction from the electrode assembly toward the cover plate, one end of the first gathering portion is connected to the active material coating portion, and the other end of the first gathering portion extends obliquely toward the peripheral wall of the through hole and extends to be connected to one end of the second gathering portion. This can increase the accommodation length of the first gathering portion inside the through hole, thereby effectively reducing the space occupied by the pole ear inside the battery cell, thereby accommodating a larger size of the active material coating portion, improving the volume energy density of the battery cell, and better reducing the redundancy of the pole ear portion in the shell, further reducing the probability of short circuit between the pole ear portion and the active material coating portion, and increasing the stability of the battery cell.

[0063] According to the second aspect of the preparation method of the battery cell of the present invention, the preparation method comprises: passing one end of the conductive part through the through hole of the pole and extending it out from the other side of the pole; welding the one end of the conductive part to the cover plate on the other side of the pole; covering the cover plate at one end of the through hole and accommodating the conductive part in the through hole; and fixing the cover plate to the pole.

[0064] According to the preparation method of the battery cell of the present invention, the cover plate and the conductive part can be welded and connected on the outside of the battery cell. In this way, the damage to the battery cell caused by the welding slag falling into the battery cell during the welding process can be reduced, thereby improving the reliability of the battery cell; at the same time, the conductive part can be accommodated in the through hole, thereby reducing the space occupied by the conductive part inside the shell, so that the shell can accommodate a larger volume of the active material coating part, thereby improving the energy density of the battery cell; in addition, the redundancy of the conductive part can be reduced, further reducing the probability of short circuit between the conductive part and the active material coating part, and increasing the stability of the battery cell.

[0065] In some embodiments, welding the one end of the conductive part to the cover plate on the other side of the pole includes: pressing the other end of the conductive part onto a side surface of the cover plate; and laser welding the other end of the conductive part to the cover plate.

[0066] In this embodiment, the other end of the conductive part is pressed onto the surface of one side of the cover plate, so as to ensure the welding gap, realize laser welding, and improve the welding quality; by using laser welding between the conductive part and the cover plate, the connection speed between the conductive part and the cover plate can be increased, and the welding quality between the conductive part and the cover plate can be improved.

[0067] The battery according to the third aspect of the present invention comprises the battery cell according to the first aspect of the present invention; or comprises the battery cell prepared by the method for preparing the battery cell according to the second aspect of the present invention.

[0068] According to the battery of the present invention, the overall performance of the battery is improved by providing the battery cell of the first aspect or the battery cell prepared by the method for preparing the battery cell of the second aspect.

[0069] The electric device according to the fourth aspect of the present invention comprises the battery according to the third aspect of the present invention, wherein the battery is used to provide electric energy.

[0070] According to the electric device of the present invention, the battery of the third aspect is provided, thereby improving the overall performance of the electric device.

[0071] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 is a schematic diagram of a vehicle according to an embodiment of the present invention;

[0073] Figure 2 is an exploded diagram of a battery according to an embodiment of the present invention;

[0074] Figure 3 is a partial schematic diagram of a battery cell according to an embodiment of the present invention;

[0075] Figure 4 is a partial schematic diagram of another state of a battery cell according to an embodiment of the present invention, wherein the battery cell is assembled;

[0076] Figure 5 is a partial schematic diagram of another state of a battery cell according to an embodiment of the present invention, wherein the cover plate covers the through hole;

[0077] Figure 6 yes Figure 5 A schematic diagram of the cover plate shown in ;

[0078] Figure 7 yes Figure 5 A schematic diagram of the pole shown in ;

[0079] Figure 8 yes Figure 5 A schematic diagram of another angle of the pole shown in FIG.

[0080] Fig. 9 yes Figure 5 A schematic diagram of another angle of the pole shown in ;

[0081] Fig.10 yes Figure 5 A schematic diagram of another angle of the pole shown in ;

[0082] Fig.11 is a schematic diagram of assembling a battery cell according to an embodiment of the present invention;

[0083] Fig.12 is a schematic diagram of assembly of a battery cell in another state according to an embodiment of the present invention, wherein one end of the conductive portion extends out of the through hole;

[0084] Fig.13 is a schematic assembly diagram of a battery cell in another state according to an embodiment of the present invention, wherein the conductive portion and the cover plate are laser welded;

[0085] Fig.14 yes Figure 3 Schematic diagram of the electrode assembly shown in .

[0086] Reference numerals:

[0087] 1. Vehicles;

[0088] 1000. Battery;

[0089] 100. Battery cell;

[0090] 10. housing; 11. first wall;

[0091] 20, pole; 21, pole body; 211, through hole; 212, groove; 22, first ring; 23, second ring;

[0092] 30. electrode assembly; 31. active material coating portion; 32. conductive portion; 321. pole ear portion; 3211. first gathering portion; 3212. second gathering portion;

[0093] 40. Cover plate; 41. Cover plate body; 42. Boss; 43. First welding area; 431. First welding molten pool; 44. Second welding area; 441. Second welding molten pool;

[0094] 50. Electrical connection piece;

[0095] 200, box body; 201, main box; 202, end cover;

[0096] 2000, controller; 3000, motor. DETAILED DESCRIPTION

[0097] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0098] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" in the specification and claims of the present invention and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0099] In the description of the embodiments of the present invention, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present invention, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0100] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0101] In the description of the embodiments of the present invention, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0102] In the description of the embodiments of the present invention, the term "plurality" refers to more than two (including two).

[0103] In the description of the embodiments of the present invention, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present invention.

[0104] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0105] At present, from the perspective of market development, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0106] In the related art, during the manufacturing of a battery cell, an active material layer is coated on a current collector and then cut to obtain a pole piece consisting of a current collector coated with an active material layer (referred to as an active material coating portion) and a current collector not coated with an active material layer (referred to as a pole lug piece), and then the positive and negative pole pieces and the separator are stacked or wound in sequence to obtain an electrode assembly, in which multiple pole lug pieces are stacked to form a pole lug portion. A pole is provided on the shell of the battery cell, and the surface of the pole facing the active material coating portion is the inner end face of the pole. During the manufacturing of the battery cell, the pole lug portion is usually welded directly to the inner end face of the pole, or indirectly welded to the inner end face of the pole through a transition piece to ensure the normal charging and discharging operation.

[0107] However, when the battery cell adopts the above structure, the pole ear and the adapter are both piled up between the active material coating part and the inner end face of the pole column, occupying a large space, so that when the size of the shell is fixed, the size of the active material coating part cannot be increased, resulting in the difficulty in improving the energy density of the battery cell. Moreover, due to design or manufacturing reasons, the length of the pole ear is usually long. When the space between the active material coating part and the inner end face of the pole column is small, the electrode assembly has a problem of pole ear redundancy after entering the shell, which easily leads to a short circuit between the pole ear or the adapter and the active material coating part, affecting the reliability and stability of the battery cell.

[0108] Based on the above considerations, in order to reduce the space occupied by the pole ear to improve the energy density of the battery cell, the present invention provides a battery cell, wherein a through hole is provided inside the pole of the battery cell, and at least part of the conductive part is provided in the through hole to reduce the space occupied by this part in the shell, thereby saving more space in the shell to accommodate the active material coating part, so that the volume of the active material coating part can be increased, which is beneficial to improve the energy density of the battery cell, and can reduce the redundancy of the pole ear part or the adapter plate in the shell, and reduce the probability of short circuit between the pole ear part or the adapter plate and the active material coating part, thereby reducing the probability of some reliability-related problems caused by short circuit, and improving the working reliability and stability of the battery cell and the battery.

[0109] The battery cell disclosed in the embodiments of the present application can be used in electrical devices that use batteries as power sources or various energy storage systems that use batteries as energy storage elements. Electrical devices can be, but are not limited to, mobile phones, tablets, laptops, electric toys, electric tools, battery cars, electric cars, ships, spacecraft, etc. Among them, electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0110] For the convenience of description, the following embodiments are described by taking a vehicle 1 as an example of an electrical device according to an embodiment of the present invention.

[0111] Reference Figure 1 , Figure 1A schematic diagram of a vehicle 1 provided for some embodiments of the present invention. Vehicle 1 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 1000 is provided inside the vehicle 1, and the battery 1000 may be provided at the bottom, the head or the tail of the vehicle 1. The battery 1000 may be used to power the vehicle 1, for example, the battery 1000 may be used as an operating power source for the vehicle 1. The vehicle 1 may also include a controller 2000 and a motor 3000, and the controller 2000 is used to control the battery 1000 to power the motor 3000, for example, for the starting, navigation and working power requirements of the vehicle 1 during driving.

[0112] In some embodiments of the present application, the battery 1000 can not only serve as an operating power source for the vehicle 1 , but also serve as a driving power source for the vehicle 1 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1 .

[0113] Reference Figure 2 , Figure 2 1 is an exploded view of a battery 1000 according to some embodiments of the present invention. The battery 1000 includes a box 200 and a battery cell 100, the box 200 has a cavity, and the battery cell 100 is accommodated in the cavity of the box 200. The box 200 is used to provide a storage space for the battery cell 100, and the box 200 can adopt a variety of structures. In some embodiments, the box 200 may include a first part (such as the main box 201 described below) and a second part (such as the end cover 202 described below), the first part and the second part cover each other, and the first part and the second part jointly define a storage space for accommodating the battery cell 100. The second part may be a hollow structure with one end open, the first part may be a plate-like structure, the first part covers the open side of the second part, so that the first part and the second part jointly define a storage space; the first part and the second part may also be hollow structures with one side open, and the open side of the first part covers the open side of the second part. Of course, the box 200 formed by the first part and the second part may be in a variety of shapes, such as a cylinder, a cuboid, etc.

[0114] In the battery 1000, there may be multiple battery cells 100, and the multiple battery cells 100 may be connected in series, in parallel, or in a mixed connection. A mixed connection means that the multiple battery cells 100 are both connected in series and in parallel. The multiple battery cells 100 may be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple battery cells 100 is accommodated in the box 200; of course, the battery 1000 may also be a battery module formed by connecting multiple battery cells 100 in series, in parallel, or in a mixed connection, and then the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in the box 200. The battery 1000 may also include other structures, for example, the battery 1000 may also include a busbar component for realizing electrical connection between the multiple battery cells 100.

[0115] Each battery cell 100 may be a secondary battery or a primary battery, or a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 100 may be cylindrical, flat, rectangular, or in other shapes.

[0116] Reference below Figure 3-Figure 14 A battery cell 100 according to an embodiment of the first aspect of the present invention is described. Figure 3 is a partial schematic diagram of a battery cell 100 according to some embodiments of the present invention, Figure 4 is a partial schematic diagram of another state of the battery cell 100 according to some embodiments of the present invention, wherein the battery cell 100 is assembled. Figure 5 is a partial schematic diagram of another state of the battery cell 100 according to some embodiments of the present invention, wherein the cover plate 40 covers the through hole 211; Figure 6 yes Figure 5 A schematic diagram of the cover plate 40 shown in FIG. Figure 7 yes Figure 5 A schematic diagram of a pole 20 is shown in FIG. Figure 8 yes Figure 5 A schematic diagram of the pole 20 at another angle shown in FIG. Fig. 9 yes Figure 5 A schematic diagram of the pole 20 at another angle shown in FIG. Fig.10 yes Figure 5 A schematic diagram of another angle of the pole 20 shown in FIG. Fig.11 is a schematic diagram of an assembly of a battery cell 100 according to some embodiments of the present invention, Fig.12 is a schematic diagram of another assembly state of a battery cell 100 according to some embodiments of the present invention, wherein one end of the conductive portion 32 extends out of the through hole 211, Fig.13 FIG. 1 is a schematic diagram of an assembly of a battery cell 100 in another state according to some embodiments of the present invention, wherein the conductive portion 32 is laser welded to the cover plate 40. Fig.14 yes Figure 3 A schematic diagram of an electrode assembly 30 is shown in FIG.

[0117] The embodiment of the present invention provides a battery cell 100, such as Figure 3 As shown, the battery cell 100 includes: a shell 10, a pole 20, a cover plate 40 and an electrode assembly 30. Specifically, the shell 10 includes a first wall 11; the pole 20 is arranged on the first wall 11 and has a through hole 211; the cover plate 40 is arranged on one side of the pole 20 and covers an end corresponding to the through hole 211; the electrode assembly 30 includes an active material coating part 31 and a conductive part 32 connected to the active material coating part 31, the active material coating part 31 is arranged in the shell 10, and at least a part of the conductive part 32 is arranged in the through hole 211 and connected to the cover plate 40.

[0118] The shape of the housing 10 can be adjusted according to the type of the battery cell 100. For example, when the battery cell 100 is a square battery 1000, the housing 10 is square. When the battery cell 100 is a cylindrical battery 1000, the housing 10 is cylindrical. In the embodiments of the present invention, the housing 10 is square as an example. Figure 3 As shown, the shell 10 can be an aluminum shell, a stainless steel shell, etc. The shell 10 is used to accommodate the electrode assembly 30 in the battery cell 100 and fix the pole 20. The first wall 11 of the shell 10 is formed in the length direction of the shell 10 (such as Figure 3 When the battery cell 100 is assembled, the electrode assembly 30 can be placed in the accommodating cavity of the shell 10, and the pole 20 is fixed on the first wall 11 of the shell 10. Specifically, the first wall 11 of the shell 10 can be provided with a thickness direction of the first wall 11 (such as Figure 3 The pole 20 is disposed in the mounting hole and is fixedly connected to the housing 10. For example, the pole 20 and the housing 10 can be fixed by welding or riveting.

[0119] The pole 20 is used to connect the battery cell 100 with the electrical connector and transmit electrical energy. The material of the pole 20 can be copper, aluminum, zinc and alloys thereof, and the shape of the pole 20 can be set to a circular, rectangular or other shape structure according to design requirements. Generally, the number of poles 20 is at least two. Specifically, the pole 20 is at least one positive pole and at least one negative pole. For example, when the number of poles 20 is two, one is a positive pole and the other is a negative pole, and the two are electrically connected to the positive and negative tabs of the electrode assembly 30 respectively; for another example, when the number of poles 20 is four, two can be positive poles and two can be negative poles. At this time, both positive poles are electrically connected to the positive tab of the electrode assembly 30, and both negative poles are electrically connected to the negative tab of the electrode assembly 30.

[0120] The cover plate 40 is sealed and connected to the pole 20 to cover the through hole 211, thereby sealing the battery cell 100 to isolate the inside of the battery cell 100 from the outside, thereby improving the reliability of the battery cell 100. At the same time, the conductive part 32 is electrically connected to the cover plate 40, and the cover plate 40 is connected to the pole 20, thereby achieving electrical connection between the conductive part 32 and the pole 20, thereby achieving the transmission of electrical energy of the battery cell 100. Optionally, the material of the cover plate 40 can be consistent with the material of the pole 20, and the shape of the cover plate 40 can be designed according to the shape of the through hole 211.

[0121] The electrode assembly 30 is usually formed by laminating or winding electrode sheets and a separator. The electrode sheets include a positive electrode sheet and a negative electrode sheet. The positive electrode tab led out from the positive electrode sheet is electrically connected to the positive electrode column 20 , and the negative electrode tab led out from the negative electrode sheet is electrically connected to the negative electrode column 20 .

[0122] The active material coating portion 31 is the portion of the electrode assembly 30 coated with active material, which can assist in the deintercalation of metal ions during the charge and discharge process of the battery cell 100. The conductive portion 32 is a metal structure that electrically connects the active material coating portion 31 and the pole 20. It is not coated with active material, and both the positive pole and the negative pole can be electrically connected to the active material coating portion 31 through the conductive portion 32 to enable the charge and discharge operations of the battery cell 100 to be carried out.

[0123] It should be noted that in the embodiment of the present application, the active material coating part 31 is divided into a positive electrode active material coating part and a negative electrode active material coating part, the positive electrode active material coating part includes a portion of the positive electrode current collector coated with a positive electrode active material layer, and the negative electrode active material coating part includes a portion of the negative electrode current collector coated with a negative electrode active material layer. The conductive part 32 is divided into a positive electrode conductive part and a negative electrode conductive part, the positive electrode conductive part electrically connects the positive electrode active material coating part and the positive electrode pole, and the negative electrode conductive part electrically connects the negative electrode active material coating part and the negative electrode pole.

[0124] For the convenience of description, the embodiments of the present invention will not distinguish between the positive and negative electrodes of the pole 20, the conductive part 32 and the active material coating part 31. The pole 20, the conductive part 32 and the active material coating part 31 involved in the embodiments of the present invention and their related descriptions can be applied to structures such as the positive pole, the negative pole, the positive active material coating part, the negative active material coating part, the positive conductive part and the negative conductive part.

[0125] In this embodiment, the pole 20 has a through hole 211, and the through hole 211 penetrates the pole 20 along the direction from the electrode assembly 30 to the cover plate 40, so that a hollow structure is formed inside the pole 20. Among them, the hollow structure can reduce the weight of the pole 20 to a certain extent, and further can improve the weight energy density of the battery cell 100 and the battery 1000 to a certain extent.

[0126] At least part of the conductive part 32 is disposed in the through hole 211, that is, the conductive part 32 can be partially disposed in the through hole 211, or can be entirely disposed in the through hole 211. Part or all of the conductive part 32 is contained in the through hole 211, so that the part of the conductive part 32 located in the containing part can occupy the space in the pole 20, thereby reducing the space occupied by the conductive part 32 in the shell 10. When the size of the shell 10 is fixed, some space can be saved in the shell 10 to accommodate a larger active material coating part 31, thereby improving the volume energy density of the battery cell 100. At the same time, the redundancy of the conductive part 32 in the shell 10 can be reduced to at least a certain extent, reducing the probability of short circuit between the conductive part 32 and the active material coating part 31, reducing the probability of short circuit of the battery cell 100, and improving the working reliability and stability of the battery cell 100 and the battery 1000.

[0127] According to the battery cell 100 of the embodiment of the present invention, by providing the pole 20 with a through hole 211, and at least part of the conductive part 32 is provided in the through hole 211, the space occupied by the conductive part 32 inside the housing 10 can be reduced, so that the housing cavity of the housing 10 can accommodate a larger active material coating part 31, thereby improving the volume energy density of the battery cell 100. At the same time, the redundancy of the conductive part 32 in the housing 10 can be reduced, the probability of short circuit between the conductive part 32 and the active material coating part 31 can be reduced, and the probability of short circuit of the battery cell 100 can be reduced, thereby improving the working reliability and stability of the battery cell 100 and the battery 1000. In addition, by providing the through hole 211 inside the pole 20, the weight of the pole 20 can also be reduced, thereby improving the weight energy density of the battery cell 100 and the battery 1000.

[0128] According to some embodiments of the present invention, the cover plate 40 is connected to the conductive portion 32 by welding.

[0129] Among them, welding connection welding can connect two objects of different sizes and different materials, and the operation is simple, and no external materials need to be added, thereby simplifying the connection process between the cover plate 40 and the conductive part 32, and reducing the production cost and overall weight of the battery cell 100; at the same time, the welding connection has high strength and good airtightness, thereby increasing the connection strength and connection stability between the cover plate 40 and the conductive part 32, thereby improving the stability of the electrical connection between the conductive part 32 and the pole 20.

[0130] In this embodiment, the cover plate 40 and the conductive part 32 are connected by welding, so that the connection strength and connection stability between the cover plate 40 and the conductive part 32 can be increased, and the stability of the electrical connection between the conductive part 32 and the pole 20 can be improved; at the same time, the connection complexity between the cover plate 40 and the conductive part 32 can be reduced, and the production cost and overall weight of the battery cell 100 can be reduced.

[0131] According to some embodiments of the present invention, Figure 4 As shown, the cover plate 40 has a first welding area 43 and a second welding area 44 . The first welding area 43 is welded to the conductive portion 32 , and the second welding area 44 is used for welding the electrical connection sheet 50 . The first welding area 43 and the second welding area 44 are different areas of the cover plate 40 .

[0132] Specifically, the electrical connecting sheet 50 is welded to the surface of the side of the cover plate 40 facing away from the electrode assembly 30, and can be used to connect two adjacent battery cells 100 to achieve series connection of the battery cells 100; one end of the conductive portion 32 is connected to the electrode assembly 30, and the other end is welded to the surface of the side of the cover plate 40 facing the electrode assembly 30, and is used to connect the internal and external connections of the electrode assembly 30 to achieve electrical connectivity of the battery cells 100.

[0133] It is understandable that during welding, under the action of the welding heat source, the local parent material on the weldment will melt, and then form a liquid metal with a certain geometric shape, which is called a molten pool. The molten pool forms a weld after cooling. Among them, the thickness at the weld position is slightly lower than that of the cover body 41, and the first welding area 43 and the second welding area 44 are set as different areas of the cover 40, which can effectively prevent the problem of reduced welding quality caused by the connection of the two welding molten pools, and then improve the welding quality of the conductive part 32 and the electrical connecting piece 50 and the cover 40, so as to improve the electrical connection stability of the battery cell 100.

[0134] In this embodiment, by setting the first welding area 43 and the second welding area 44, the welding positions of the conductive part 32 and the electrical connecting piece 50 can be respectively limited, thereby increasing the convenience and reliability of assembling the battery cell 100; at the same time, by setting the first welding area 43 and the second welding area 44 as different areas of the cover plate 40, the problem of reduced welding quality caused by the connection of the two welding pools can be effectively prevented, thereby improving the welding quality of the conductive part 32 and the electrical connecting piece 50 with the cover plate 40, thereby improving the electrical connection stability of the battery cell 100.

[0135] According to some embodiments of the present invention, Figure 4 As shown, the first welding area 43 and the second welding area 44 are respectively formed on both sides of a center line of the cover plate 40 that is perpendicular to the length direction or the width direction.

[0136] That is, in some embodiments, the first welding area 43 and the second welding area 44 are respectively formed on both sides of the center line of the cover plate 40 perpendicular to the length direction; in other embodiments, the first welding area 43 and the second welding area 44 are respectively formed on both sides of the center line of the cover plate 40 perpendicular to the width direction.

[0137] In this embodiment, the first welding area 43 and the second welding area 44 are respectively formed on both sides of the center line of the cover plate 40 perpendicular to the length direction or the width direction, which can facilitate further limiting the positions of the first welding area 43 and the second welding area 44, thereby increasing the convenience and reliability of assembling the battery cell 100.

[0138] According to some embodiments of the present invention, the distance between the first welding area 43 and the second welding area 44 is less than or equal to two-thirds of the width of the cover plate 40 .

[0139] For example, the distance between the first welding area 43 and the second welding area 44 may be one third of the width of the cover plate 40 , or may be two thirds of the width of the cover plate 40 .

[0140] In this embodiment, the spacing between the first welding area 43 and the second welding area 44 is set to be less than or equal to two-thirds of the width of the cover plate 40, so that the spacing between the first welding area 43 and the second welding area 44 is not too large, which is beneficial to ensure the welding area of ​​the first welding area 43 and the second welding area 44 on the cover plate 40, so as to facilitate the connection between the conductive part 32 and the electrical connecting piece 50 and the cover plate 40, and ensure the welding quality of the conductive part 32 and the electrical connecting piece 50 and the cover plate 40, thereby improving the electrical connection stability of the battery cell 100.

[0141] According to some embodiments of the present invention, the distance between the first welding area 43 and the second welding area 44 is greater than or equal to one third of the width of the cover plate 40 .

[0142] That is, the distance between the first welding area 43 and the second welding area 44 is greater than or equal to one third of the width of the cover plate 40 , and less than or equal to two thirds of the width of the cover plate 40 .

[0143] For example, the distance between the first welding area 43 and the second welding area 44 is d, and the width of the cover plate 40 is w, then the value range of d is [w / 3, 2w / 3].

[0144] In this embodiment, by setting the spacing between the first welding area 43 and the second welding area 44 to be greater than or equal to one third of the width of the cover plate 40, the spacing between the first welding area 43 and the second welding area 44 is not too small, which can effectively prevent the problem of reduced welding quality caused by the connection of two welding pools, and further improve the welding quality of the conductive part 32 and the electrical connecting piece 50 and the cover plate 40, thereby improving the electrical connection stability of the battery cell 100.

[0145] According to some embodiments of the present invention, the distance between the first welding area 43 and the second welding area 44 is greater than or equal to 2 mm.

[0146] For example, the distance between the first welding area 43 and the second welding area 44 may be 2 mm, 2.5 mm, 3 mm or more, and the distance may be designed according to actual conditions.

[0147] In this embodiment, by setting the spacing between the first welding area 43 and the second welding area 44 to be greater than or equal to 2 mm, the problem of reduced welding quality caused by the connection of the two welding pools can be effectively prevented, thereby improving the welding quality of the conductive part 32 and the electrical connecting piece 50 and the cover plate 40, thereby improving the electrical connection stability of the battery cell 100.

[0148] According to some embodiments of the present invention, the first welding area 43 is welded with the conductive part 32 to form a first welding pool 431 , and the second welding area 44 is welded with the electrical connecting piece 50 to form a second welding pool 441 . The first welding pool 431 and the second welding pool 441 are spaced apart.

[0149] Among them, the molten pool refers to the part of the base material that is melted into a pool due to the heat of the welding arc. The liquid metal part with a certain geometric shape formed on the weldment during fusion welding is called the molten pool, and the molten pool forms a weld after cooling.

[0150] In this embodiment, by arranging the first welding pool 431 and the second welding pool 432 to be spaced apart, the problem of the first welding pool 431 and the second welding pool 432 being connected can be effectively solved, thereby improving the welding quality of the conductive part 32 and the electrical connecting piece 50 and the cover plate 40, thereby improving the electrical connection stability of the battery cell 100.

[0151] According to some embodiments of the present invention, the ratio of the thickness of the cover plate 40 to the thickness of the first wall 11 is 1-4.

[0152] Among them, the shell 10 is mainly used to isolate the interior of the battery cell 100 from the outside, protect the battery cell 100, and ensure the safety of the battery cell 100. Therefore, the structural strength of the shell 10 must be sufficient to resist the expansion force of the battery cell without breaking, and the reaction force is applied to the electrode assembly 30 to fix the electrode assembly 30. Therefore, the thickness of the first wall 11 must meet the strength required by the shell 10 and the lightweight requirement of the battery cell 100.

[0153] For example, the ratio of the thickness of the cover plate 40 to the thickness of the first wall 11 may be 1, 2, 3 or 4.

[0154] In this embodiment, by setting the ratio of the thickness of the cover plate 40 to the thickness of the first wall 11 to 1-4, the thickness of the cover plate 40 can meet the welding requirements of the conductive part 32 and the electrical connecting piece 50, while the thickness of the cover plate 40 is not too thick, which is beneficial to the lightweight of the battery cell 100.

[0155] According to some embodiments of the present invention, the ratio of the thickness of the cover plate 40 to the thickness of the first wall 11 is 2-3.

[0156] For example, the ratio of the thickness of the cover plate 40 to the thickness of the first wall 11 may be 2, 2.5 or 3.

[0157] In this embodiment, by setting the ratio of the thickness of the cover plate 40 to the thickness of the first wall 11 to 2-3, the thickness of the cover plate 40 can be further limited, so that the thickness of the cover plate 40 is not too large, which is beneficial to the lightweight of the battery cell 100; at the same time, the thickness of the cover plate 40 is not too small, so that it can meet the welding requirements of the conductive part 32 and the electrical connecting piece 50 and the structural strength requirements of the battery cell 100.

[0158] According to some embodiments of the present invention, the thickness of the cover plate 40 is greater than or equal to 1.5 mm and less than or equal to 5 mm.

[0159] The thickness of the cover plate 40 is related to the welding requirements of the conductive portion 32 and the electrical connection sheet 50 .

[0160] For example, the thickness a of the cover plate 40 may be 1.5 mm, 2 mm, 3 mm, 4 mm or 5 mm.

[0161] In this embodiment, by setting the thickness of the cover plate 40 to be greater than or equal to 1.5 mm and less than or equal to 5 mm, the thickness of the cover plate 40 can be controlled not to be too large while meeting the welding requirements of the conductive portion 32 and the electrical connecting piece 50, thereby reducing the occupation of the internal space of the through hole 211 by the cover plate 40, thereby improving the space utilization rate of the battery cell 100.

[0162] According to some embodiments of the present invention, Figure 5 As shown, the cover plate 40 includes a cover plate body 41 and a boss 42 . The cover plate body 41 covers one end of the through hole 211 . The boss 42 is arranged on a side surface of the cover plate body 41 facing the electrode assembly 30 and extends into the through hole 211 . The conductive part 32 is connected to the boss 42 .

[0163] Specifically, the cover plate body 41 is mainly used to seal the end of the through hole 211 away from the electrode assembly 30 to achieve the sealing of the battery cell 100; the boss 42 extends into the through hole 211, and the size of the boss 42 can be adapted to the through hole 211. The boss 42 can be used to further block the side of the through hole 211 away from the electrode assembly 30, and then further seal the through hole 211, further reduce the risk of electrolyte leakage from the through hole 211, and improve the reliability of the battery cell 100.

[0164] The electrical connection piece 50 is welded to the side of the cover plate body 41 away from the boss 42, and the conductive part 32 is welded to the side of the boss 42 away from the cover plate body 41. In this way, the occurrence of molten pool connection during the welding process can be further reduced, and the welding quality of the conductive part 32 and the electrical connection piece 50 and the cover plate 40 can be further improved, thereby improving the electrical connection stability of the battery cell 100.

[0165] Furthermore, the cover plate body 41 and the boss 42 can be an integral part or a split part. The integral part can reduce the production process of the cover plate 40, reduce the production steps of the cover plate 40, and thereby increase the production rate of the cover plate 40 and reduce the production cost of the cover plate 40; the split part can reduce the production difficulty of the cover plate 40 and reduce the mold opening cost of the cover plate 40, thereby reducing the production cost of the cover plate 40.

[0166] In this embodiment, by providing the cover plate body 41 and the boss 42, the sealing effect between the cover plate 40 and the pole 20 can be increased, the risk of electrolyte leakage from the through hole 211 can be further reduced, and the reliability of the battery cell 100 can be improved; at the same time, the occurrence of the molten pool being connected during the welding process can be further reduced, and the welding quality of the conductive part 32 and the electrical connecting piece 50 and the cover plate 40 can be further improved, thereby improving the electrical connection stability of the battery cell 100.

[0167] According to some embodiments of the present invention, Figure 6 As shown, the height of the boss 42 protruding from the side surface of the cover plate body 41 is 1mm-5mm.

[0168] For example, the height c of the boss 42 protruding from the surface of one side of the covered plate body 41 may be 1 mm, 2 mm, 3 mm, 4 mm or 5 mm.

[0169] In this embodiment, the height of the boss 42 protruding from the side surface of the cover plate body 41 is set to 1mm-5mm, so that the thickness of the boss 42 will not be too large, which is beneficial to reduce the occupation of the internal space of the through hole 211 by the cover plate 40, thereby improving the space utilization rate of the battery cell 100; it also ensures that the thickness of the boss 42 is not too small, so that the thickness of the boss 42 meets the welding requirements of the conductive part 32, thereby increasing the connection stability between the conductive part 32 and the boss 42.

[0170] According to some embodiments of the present invention, the height of the boss 42 protruding from the surface of one side of the covered plate body 41 is 1.5 mm-3 mm.

[0171] For example, the height of the boss 42 protruding from the surface of one side of the covered plate body 41 may be 1.5 mm, 2 mm, 2.5 mm or 3 mm.

[0172] In this embodiment, the height of the boss 42 protruding from the side surface of the cover plate body 41 is set to 1.5mm-3mm, so that the thickness of the boss 42 can meet the welding requirements of the conductive part 32, and at the same time, the occupation of the internal space of the through hole 211 by the cover plate 40 can be further reduced, thereby further improving the space utilization rate of the battery cell 100.

[0173] According to some embodiments of the present invention, the boss 42 is clearance-matched with one end of the through hole 211 , and the clearance between the boss 42 and the through hole 211 is 0-0.1 mm.

[0174] Specifically, clearance fit refers to fit with a gap, that is, when the boss 42 fits with the through hole 211, a gap is formed between the outer wall of the boss 42 and the inner wall of the through hole 211. The minimum gap may be zero.

[0175] For example, the matching clearance between the boss 42 and the through hole 211 may be 0 mm, 0.01 mm, 0.02 mm, 0.04 mm, 0.06 mm, 0.08 mm or 0.1 mm.

[0176] In this embodiment, the boss 42 is provided with a clearance fit between one end of the through hole 211 , and the clearance between the boss 42 and the through hole 211 is 0-0.1 mm, which facilitates the boss 42 to enter and exit the through hole 211 , thereby reducing the difficulty of assembling the cover plate 40 and the pole 20 .

[0177] According to some embodiments of the present invention, the matching clearance between the boss 42 and the through hole 211 is less than or equal to 0.05 mm.

[0178] For example, the matching clearance between the boss 42 and the through hole 211 may be 0 mm, 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm or 0.05 mm.

[0179] In this embodiment, by setting the matching clearance between the boss 42 and the through hole 211 to be less than or equal to 0.05 mm, the clearance between the boss 42 and the inner wall of the through hole 211 can be further reduced, thereby further improving the blocking effect of the boss 42 on the through hole 211, reducing the risk of electrolyte leakage from the cover plate 40, and thus improving the reliability of the battery cell 100.

[0180] According to some embodiments of the present invention, the pole 20 is a negative pole, the cover plate body 41 and the boss 42 are separate parts, the cover plate body 41 and the boss 42 are made of different materials, the material of the boss 42 is the same as the material of the conductive part 32, and when the boss 42 is welded to the conductive part 32, the depth of the molten pool on the cover plate 40 is less than the thickness of the boss 42.

[0181] Specifically, the negative electrode column is connected to the negative electrode active material coating part through the negative electrode conductive part, the material of the conductive part 32 is the same as the material of the current collector of the active material coating part 31, the boss 42 is welded to the conductive part 32, and then the material of the boss 42 is the same as the material of the negative electrode current collector. The cover body 41 is welded to the electrical connection sheet 50, and then the material of the cover body 41 can be the same as the material of the electrical connection sheet 50.

[0182] For example, in some specific embodiments, the negative electrode current collector is made of copper, that is, the conductive part 32 is made of copper, and the material of the electrical connection sheet 50 is generally aluminum. Therefore, the material of the boss 42 can be copper, and the material of the cover plate body 41 can be aluminum. Among them, welding the same materials to each other can reduce the difficulty of welding and improve the welding quality. Therefore, the conductive part 32, the negative electrode current collector and the boss 42 are made of the same material, which can reduce the difficulty of welding the conductive part 32 with the negative electrode current collector and the conductive part 32 with the boss 42, and improve the welding quality of the conductive part 32 with the negative electrode current collector and the conductive part 32 with the boss 42; the cover plate body 41 and the electrical connection sheet 50 are made of the same material, which can also reduce the difficulty of welding the electrical connection sheet 50 with the cover plate body 41 and improve the welding quality of the electrical connection sheet 50 with the cover plate body 41.

[0183] In this embodiment, the pole 20 is a negative pole, and the cover plate body 41 and the boss 42 are separate parts, and the material of the boss 42 is the same as the material of the conductive part 32. In this way, the material of the boss 42 can be adapted to the material of the conductive part 32, thereby increasing the welding quality of the boss 42 and the conductive part 32, and increasing the connection stability of the boss 42 and the conductive part 32. In addition, when the boss 42 is welded to the conductive part 32, the molten pool depth on the cover plate 40 is less than the thickness of the boss 42, and the welding position is controlled between the same materials. In this way, the welding quality of the boss 42 and the conductive part 32 can be further increased, and the welding difficulty of the boss 42 and the conductive part 32 can be reduced.

[0184] According to some embodiments of the present invention, the pole 20 is a positive pole, the boss 42 and the cover plate body 41 are integrally formed, and when the cover plate 40 and the conductive part 32 are welded, the depth of the molten pool on the boss 42 is greater than the thickness of the boss 42 .

[0185] Specifically, the positive electrode column is connected to the positive active material coating part through the positive electrode conductive part. The material of the conductive part 32 is the same as the material of the current collector of the active material coating part 31 , and the material of the boss 42 can be the same as the material of the positive electrode current collector.

[0186] For example, in some specific embodiments, the positive electrode current collector is made of aluminum, that is, the conductive part 32 and the boss 42 can both be made of aluminum, and the material of the electrical connection sheet 50 is generally also aluminum. Furthermore, the cover body 41 can be made of aluminum, so that the cover body 41 and the boss 42 are made of the same material.

[0187] In this embodiment, when the pole 20 is a positive pole, the boss 42 is formed integrally with the cover plate body 41, so that the cover plate 40 meets the welding requirements with the electrical connecting piece 50 and the conductive part 32, and can also reduce the production process of the cover plate 40, reduce the production steps of the cover plate 40, and thus can improve the production rate of the cover plate 40 and reduce the production cost of the cover plate 40.

[0188] According to some embodiments of the present invention, the pole 20 is connected to the cover plate 40 by welding.

[0189] Among them, welding connection welding can connect two objects of different sizes and different materials, and the operation is simple, and no external materials need to be added, thereby simplifying the connection process between the cover plate 40 and the pole 20, and reducing the production cost and overall weight of the battery cell 100; at the same time, the welding connection has high strength and good airtightness, thereby increasing the connection stability and sealing between the cover plate 40 and the pole 20, thereby improving the sealing of the battery cell 100.

[0190] In this embodiment, by arranging the electrode 20 and the cover plate 40 to be welded, the connection stability and sealing performance between the electrode 20 and the cover plate 40 can be increased, thereby improving the airtightness of the battery cell 100 and thus improving the reliability of the battery cell 100 .

[0191] According to some embodiments of the present invention, Figure 7-Figure 11 As shown, the pole 20 is a hollow ring and defines a through hole 211 inside.

[0192] Specifically, the pole 20 is a hollow ring, that is, the interior of the pole 20 is formed into a relatively large hollow structure, and the transverse cross-section of the pole 20 is formed into a ring. The ring may include various shapes, such as rectangular, circular, prismatic, etc.

[0193] In this embodiment, the pole 20 is configured as a hollow ring and a through hole 211 is defined on the inner side, so that the weight of the pole 20 can be reduced to a certain extent, thereby improving the weight energy density of the battery cell 100 and the battery 1000; at the same time, the hollow ring has a large internal cavity volume, so that the conductive part 32 can be easily extended out of the through hole 211, thereby reducing the difficulty of welding the conductive part 32 and the cover plate 40, reducing the difficulty of assembling the battery cell 100, and improving the assembly rate of the battery cell 100.

[0194] According to some embodiments of the present invention, Figure 7-Figure 11 As shown, the pole 20 includes: a pole body 21, a first ring 22 and a second ring 23. The pole body 21 is annular and defines a through hole 211 on the inner side; the first ring 22 is connected to one end of the pole body 21 facing the electrode assembly 30, and the first ring 22 extends radially outwardly of the pole body 21 and extends circumferentially of the pole body 21 to form a ring; the second ring 23 is connected to the other end of the pole body 21 away from the electrode assembly 30, and the second ring 23 extends radially outwardly of the pole body 21 and extends circumferentially of the pole body 21 to form a ring.

[0195] The pole body 21 is formed in a ring shape. For example, the cross section of the pole body 21 can be formed in a ring structure such as a circular ring, a rectangle, or a diamond.

[0196] The surface of the first ring 22 on one side facing the electrode assembly 30 can be flush with the surface of the pole body 21 on one side facing the electrode assembly 30, the shape of the first ring 22 can match the shape of the pole body 21, the first ring 22 and the pole body 21 can be separately provided or integrally formed, the material of the first ring 22 can be the same as or different from the material of the pole body 21, the axial thickness of the first ring 22 on the pole body 21 can be reasonably set according to the installation and assembly requirements of the pole 20, optionally, the first ring 22 can be formed by flanging along the radial outward of the pole body 21 at one end of the pole body 21 facing the electrode assembly 30.

[0197] The side surface of the second ring 23 facing the electrode assembly 30 can be arranged flush with the side surface of the pole body 21 facing away from the electrode assembly 30, the shape of the second ring 23 can match the shape of the pole body 21, the second ring 23 and the pole body 21 can be separately arranged or integrally formed, the material of the second ring 23 can be the same as or different from the material of the pole body 21, and the axial thickness of the second ring 23 in the pole body 21 can be reasonably set according to the installation and assembly requirements of the pole 20. Optionally, the second ring 23 can be formed by flanging the end of the pole body 21 away from the electrode assembly 30 along the radial outward of the pole body 21.

[0198] In this embodiment, the first ring 22 and the second ring 23 are respectively provided at both ends of the pole body 21. The first ring 22 and the second ring 23 can improve the structural strength of the pole body 21 to a certain extent, so that the overall structural strength of the pole 20 is better, so that the pole 20 is more stable and reliable when connected and fixed to the pole ear, and the pole 20 can better participate in the power transmission operation of the battery cell 100. The first ring 22 and the second ring 23 can cooperate with the pole body 21 to form a slot structure, so as to facilitate the installation and fixation of the pole 20 in the battery cell 100. The first ring 22 and the second ring 23 are simple in structure and easy to use.

[0199] According to some embodiments of the present invention, Fig.11 As shown, a groove 212 is formed on the surface of the electrode column 20 facing away from the electrode assembly 30 , a through hole 211 is formed inside the groove 212 and passes through the bottom wall of the groove 212 , and the cover plate 40 is disposed in the groove 212 .

[0200] Specifically, the shape of the groove 212 can be adapted to the shape and structure of the cover plate 40, and the depth of the groove 212 can be adapted to the thickness of the cover plate 40. The axis of the groove 212 can be colinear with the axis of the through hole 211. When the cover plate 40 is assembled with the electrode column 20, the surface of one side of the cover plate 40 facing the electrode assembly 30 abuts against the bottom of the groove 212, and the peripheral edge of the cover plate 40 abuts against the groove wall of the groove 212.

[0201] The groove 212 is connected to the through hole 211, and the through hole 211 passes through the bottom wall of the groove 212. The diameter of the through hole 211 is smaller than the diameter of the groove 212. The cover plate 40 abuts against the bottom wall of the groove 212 on the side facing the electrode assembly 30, and can be used to cover the through hole 211 to seal the battery cell 100, thereby effectively preventing the electrolyte from leaking from the through hole 211, thereby improving the reliability of the battery cell 100.

[0202] In this embodiment, a groove 212 is formed on the surface of the pole 20 on one side away from the electrode assembly 30 , so that the cover plate 40 and the pole 20 can be positioned more conveniently when fixed, and the connection and fixation are more stable and reliable.

[0203] According to some embodiments of the present invention, Fig.11 As shown, in the direction from the electrode assembly 30 toward the cap plate 40 , the sidewall of the groove 212 extends outwardly and obliquely along the radial direction of the through hole 211 .

[0204] Specifically, the side wall of the groove 212 extends outwardly along the radial direction of the connecting hole, and the inclination angle of the side wall can be reasonably set according to the installation and fixation requirements of the cover plate 40. The extension direction of the side wall of the groove 212 can be adapted to the extension direction of the periphery of the cover plate 40, and the side wall of the groove 212 can abut against the peripheral wall of the cover plate 40.

[0205] For example Fig.11 As shown, the longitudinal cross-section of the groove 212 can be formed into a trapezoid that is wide at the top and narrow at the bottom, and the side wall of the groove 212 is formed into an outwardly inclined slope. In this way, when the cover plate 40 and the pole 20 are assembled, it can guide the assembly of the cover plate 40, so that the cover plate 40 can smoothly enter the groove 212. At the same time, the inclined slope has a relatively larger area than the vertical plane, thereby increasing the contact area between the cover plate 40 and the pole 20, increasing the welding width during welding, and thereby improving the sealing effect between the cover plate 40 and the pole 20.

[0206] In this embodiment, by setting the side wall of the groove 212 to extend outwardly along the radial direction of the through hole 211, it can play a certain guiding role when assembling the cover plate 40 and the pole 20, so that the cover plate 40 can be more conveniently fixed in the groove 212, with a simple structure and easy assembly. At the same time, when the cover plate 40 and the pole 20 are welded, the peripheral edge of the cover plate 40 and the inclined side wall of the groove 212 can also increase the welding width during welding, so that the cover plate 40 and the pole 20 have a higher welding quality, thereby increasing the welding sealing effect of the cover plate 40 and the pole 20, and increasing the sealing of the battery cell 100.

[0207] According to some embodiments of the present invention, a surface of one side of the cap plate 40 facing away from the electrode assembly 30 is flush with an end surface of one end of the electrode column 20 facing away from the electrode assembly 30 .

[0208] It can be understood that after the cover plate 40 is assembled with the pole 20, the cover plate 40 can cooperate with the pole 20 to form a continuous plane on the side of the pole 20 facing away from the electrode assembly 30. Specifically, the side surface of the second ring 23 facing away from the electrode assembly 30 can be flush with the side surface of the pole 20 facing away from the electrode assembly 30 and the side surface of the cover plate 40 facing away from the electrode assembly 30.

[0209] For example Figure 4-Figure 5 As shown, the upper surface of the cover plate 40 is flush with the upper surface of the second ring 23 of the pole 20 .

[0210] In this embodiment, by setting the side surface of the cover plate 40 facing away from the electrode assembly 30 to be flush with the end surface of the pole 20 facing away from the electrode assembly 30, the cover plate 40 and the pole 20 can cooperate to form a continuous plane, thereby reducing the space occupied by the cover plate 40 to a certain extent and increasing the electrical connection surface of the pole 20 of the battery cell 100, so that the energy density of the battery cell 100 can be improved to a certain extent, and the battery cell 100 can be more conveniently electrically connected to the electrical connector through the end of the pole 20 facing away from the electrode assembly 30; at the same time, the appearance of the battery cell 100 can also be improved.

[0211] According to some embodiments of the present invention, the active material coating portion 31 includes a current collector and an active material layer disposed on the current collector, the conductive portion 32 includes a pole ear portion 321 electrically connected to the current collector, the pole ear portion 321 includes a plurality of pole ear sheets, the plurality of pole ear sheets converge at a position close to the current collector to form a first gathering portion 3211, the plurality of pole ear sheets converge at a position away from the current collector and are connected to form a second gathering portion 3212, the first gathering portion 3211 connects the second gathering portion 3212 and the active material coating portion 31, and at least a portion of the second gathering portion 3212 is accommodated in the through hole 211.

[0212] Specifically, the current collector is a component used to carry active materials and collect and output the current generated by the active materials of the battery. Among them, the current collector includes a positive electrode current collector and a negative electrode current collector, and the materials of the positive electrode current collector and the negative electrode current collector are different. For example, taking a lithium-ion battery as an example, the positive electrode current collector can be aluminum and the negative electrode current collector can be copper.

[0213] The active material layer is mainly coated on the current collector, and the active material layer includes a positive electrode active material layer and a negative electrode active material layer. The functions of the positive electrode active material layer and the negative electrode active material are different, and thus the materials of the positive electrode active material layer and the negative electrode active material are also different. For example, taking lithium-ion batteries as an example, the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc., and the negative electrode active material can be carbon or silicon, etc.

[0214] The pole ear portion 321 is the contact point when the battery cell 100 is charged and discharged. The pole ear portion 321 includes a plurality of pole ear sheets, for example, the number of pole ear sheets can be two, three, four or more. Among them, the pole ear sheet is a structure electrically connected to the current collector but not coated with active material, and can be formed by direct die cutting of the current collector.

[0215] In the above technical solution, when forming the first gathered portion 3211, the plurality of pole tabs are only gathered (i.e., gathered in a direction close to each other) but not connected, while when forming the second gathered portion 3212, the plurality of pole tabs are not only gathered but also connected into an integrated structure. For example, the plurality of pole tabs can be connected into an integrated plate structure by welding (e.g., ultrasonic welding) to form the second gathered portion 3212, and for example, the plurality of pole tabs can be gathered and connected to form the second gathered portion 3212 by bonding with conductive adhesive, etc., which will not be described in detail here.

[0216] It should be noted that in the embodiment of the present application, the tab sheets are divided into positive tab sheets and negative tab sheets. The tab sheets of the positive electrode that need to be gathered together are stacked together and ultrasonically pre-welded to form the second gathered portion 3212 of the positive electrode, which can reduce the gap between layers, so that the fluffy multiple tab sheets of the positive electrode form a plate structure with a certain rigidity. Similarly, the tab sheets of the negative electrode that need to be gathered together are stacked together and ultrasonically pre-welded to form the second gathered portion 3212 of the negative electrode, which can reduce the gap between layers, so that the fluffy multiple tab sheets of the negative electrode form a plate structure with a certain rigidity.

[0217] In the above technical solution, "a plurality of pole tabs converge at positions close to the current collector to form a first gathering portion 3211, and a plurality of pole tabs converge at positions away from the current collector and connect to form a second gathering portion 3212" is intended to illustrate that: along the extension direction of the pole tab, the first gathering portion 3211 and the second gathering portion 3212 are sequentially arranged along the direction away from the current collector, and the specific positions of the first gathering portion 3211 and the second gathering portion 3212 are not limited, that is, it is not required how close the first gathering portion 3211 is to the current collector, nor how far the second gathering portion 3212 is from the current collector. In some optional examples, the current collector and the pole tab may be an integral part, for example, for the positive pole sheet, it may be an integrally formed aluminum foil, and for example, for the negative pole sheet, it may be an integrally formed copper foil, and so on.

[0218] In this embodiment, a plurality of pole tabs are arranged to converge and connect to form a second gathered portion 3212, so that the second gathered portion 3212 can have a smaller size and thickness, so that the pole tab portion 321 can be more easily and conveniently inserted into the through hole 211 and connected to the cover plate 40, thereby increasing the convenience of connecting the conductive portion 32 and the cover plate 40. At the same time, the risk of short circuit between the pole tab and the active material coating portion 31 below the pole tab portion 321 caused by the bifurcation of the plurality of pole tabs can be effectively reduced, thereby improving the reliability of the battery cell 100. In addition, at least a portion of the second gathered portion 3212 is arranged to be accommodated in the through hole 211, so that the space of the pole column 20 can be fully utilized, and the volume energy density of the battery cell 100 can be improved.

[0219] According to some embodiments of the present invention, Fig.14 As shown, the conductive portion 32 is fixedly connected to the cover plate 40 via the second retracted portion 3212 .

[0220] In this embodiment, the conductive portion 32 is fixedly connected to the cover plate 40 through the second retracted portion 3212 , so that the structure of the battery cell 100 can be simplified, the use of parts can be reduced, the assembly process can be simplified, and the assembly efficiency can be improved.

[0221] According to some embodiments of the present invention, at least a portion of the first gathering portion 3211 is accommodated in the through hole 211 .

[0222] That is to say, at least a portion of the first gathered portion 3211 and at least a portion of the second gathered portion 3212 are both accommodated in the through hole 211 .

[0223] By arranging that at least a portion of the first folded portion 3211 is accommodated in the through hole 211, this embodiment can make more effective use of the space in the pole 20, further reduce the space occupied by the pole ear portion 321 in the shell 10, so as to accommodate a larger active material coating portion 31, thereby improving the volume energy density of the battery cell 100, and better reduce the redundancy of the pole ear portion 321 in the shell 10, further reducing the probability of short circuit between the pole ear portion 321 and the active material coating portion 31.

[0224] According to some embodiments of the present invention, the active material coating portion 31 includes a current collector and an active material layer disposed on the current collector, the conductive portion 32 includes a pole ear portion 321 electrically connected to the current collector, the pole ear portion 321 includes a plurality of pole ear sheets, the plurality of pole ear sheets converge at a position close to the current collector to form a first gathering portion 3211, the plurality of pole ear sheets converge at a position away from the current collector and are connected to form a second gathering portion 3212, the first gathering portion 3211 connects the second gathering portion 3212 and the active material coating portion 31; the conductive portion 32 also includes a transfer sheet, the transfer sheet is connected to the second gathering portion 3212, the conductive portion 32 is electrically connected to the cover plate 40 through the transfer sheet, and at least a portion of the transfer sheet is accommodated in the through hole 211.

[0225] Specifically, the active material coating portion 31 can be electrically connected to the cover plate 40 through the first gathering portion 3211, the second gathering portion 3212, and the adapter sheet in sequence, and the position where the conductive portion 32 is electrically connected to the cover plate 40 is located on the adapter sheet, for example, the electrical connection can be achieved by welding (for example, laser welding) the adapter sheet and the cover plate 40. In addition, the adapter sheet and the pole tab sheet are two separate components, and are connected by welding (for example, ultrasonic welding) or the like.

[0226] It is understandable that, in this example, at least a portion of the second gathering portion 3212 is also accommodated in the through hole 211 , and at least a portion of the first gathering portion 3211 may also be accommodated in the through hole 211 , or may not be accommodated in the through hole 211 .

[0227] In this embodiment, by providing the adapter sheet, at least part of the second folded portion 3212 and at least part of the adapter sheet can be accommodated in the through hole 211, so that the space in the pole 20 can be more fully utilized, and the space occupied by the conductive portion 32 in the housing 10 can be further reduced, so as to improve the volume energy density of the battery cell 100. At the same time, the adapter sheet can be used to avoid the second folded portion 3212 and welded to the pole 20, so that the welding between the adapter sheet and the pole 20 is more reliable, the risk of welding cracking is small, and the reliability and stability of the battery cell 100 can be further improved; at the same time, the pole 20 and the pole tab sheet are electrically connected through the adapter sheet, which can also simplify the structure of the pole tab sheet.

[0228] According to some embodiments of the present invention, at least a portion of the second gathered portion 3212 is located in the through hole 211 ; or, the entire second gathered portion 3212 is located in the through hole 211 , and at least a portion of the first gathered portion 3211 is located in the through hole 211 .

[0229] It can be understood that in some specific embodiments of the present invention, the second gathering portion 3212 can be partially located in the through hole 211, or can be completely located in the through hole 211, and the first gathering portion 3211 can be at least partially located in the through hole 211, or can be not located in the through hole 211.

[0230] In some other specific embodiments of the present invention, the second gathering portion 3212 is entirely located in the through hole 211, and at least a portion of the first gathering portion 3211 is located in the through hole 211. Among them, at least a portion of the first gathering portion 3211 is located in the through hole 211, that is, the first gathering portion 3211 may be partially located in the through hole 211, or may be entirely located in the through hole 211.

[0231] In this embodiment, by arranging that at least a portion of the second gathering portion 3212 is located in the through hole 211, the space in the pole 20 can be fully utilized, and the space occupied by the pole ear portion 321 in the shell 10 can be further reduced, so as to improve the volume energy density of the battery cell 100; by arranging that the second gathering portion 3212 is entirely located in the through hole 211, and at least a portion of the first gathering portion 3211 is located in the through hole 211, the space in the pole 20 can be more fully utilized, and the space occupied by the pole ear portion 321 in the shell 10 can be greatly reduced, thereby greatly improving the volume energy density of the battery cell 100; at the same time, the redundancy of the pole ear portion 321 in the shell 10 can be further reduced, and the probability of short circuit between the pole ear portion 321 and the active material coating portion 31 can be further reduced.

[0232] According to some embodiments of the present invention, the second gathering portion 3212 extends along the surface of the cover plate 40, and in the direction from the electrode assembly 30 toward the cover plate 40, one end of the first gathering portion 3211 is connected to the active material coating portion 31, and the other end of the first gathering portion 3211 extends obliquely toward the peripheral wall of the through hole 211 and extends to be connected to one end of the second gathering portion 3212.

[0233] Specifically, in the direction from the electrode assembly 30 to the cover plate 40, the first gathering portion 3211 and the second gathering portion 3212 are arranged in sequence, and the active material coating portion, the first gathering portion 3211 and the second gathering portion 3212 are connected in sequence. When the cover plate 40 is fixedly connected to the pole 20, the second gathering portion 3212 extends along the surface of the cover plate 40, and the end of the first gathering portion 3211 away from the active material coating portion 31 extends obliquely toward the peripheral wall of the through hole 211, that is, the pole ear portion 321 is formed in a "Z" shape in the through hole 211, thereby reducing the space occupied by the pole ear portion 321.

[0234] In this embodiment, the second gathering portion 3212 is arranged to extend along the surface of the cover plate 40. In the direction from the electrode assembly 30 toward the cover plate 40, one end of the first gathering portion 3211 is connected to the active material coating portion 31, and the other end of the first gathering portion 3211 extends obliquely toward the peripheral wall of the through hole 211 and extends to be connected to one end of the second gathering portion 3212. This can increase the accommodation length of the first gathering portion 3211 inside the through hole 211, thereby effectively reducing the space occupied by the pole ear inside the battery cell 100, thereby accommodating a larger size of the active material coating portion 31, improving the volume energy density of the battery cell 100, and better reducing the redundancy of the pole ear portion 321 in the shell 10, further reducing the probability of short circuit between the pole ear portion 321 and the active material coating portion 31, and increasing the stability of the battery cell 100.

[0235] According to the second aspect of the present invention, the preparation method of the battery cell 100 includes: passing one end of the conductive part 32 through the through hole 211 of the pole 20 and extending it from the other side of the pole 20; welding one end of the conductive part 32 to the cover plate 40 on the other side of the pole 20; covering one end of the through hole 211 with the cover plate 40 so that the conductive part 32 is accommodated in the through hole 211; and fixing the cover plate 40 to the pole 20.

[0236] Among them, one end of the conductive part 32 refers to the end away from the active material coating part 31, which can also be understood as one end of the second gathering part 3212 or the adapter; the other side of the pole 20 refers to the side of the second ring 23 of the pole 20 away from the active material coating part 31; one end of the through hole 211 refers to the end of the through hole 211 away from the active material coating part 31.

[0237] In this embodiment, there are many ways to pass one end of the conductive part 32 through the through hole 211 of the pole 20. For example, the electrode assembly 30 can be laid flat, and then a cylinder can be used to push the electrode assembly 30 toward the pole 20, so that the conductive part 32 passes through the through hole 211 and extends out of the battery cell 100 from the side of the pole 20 away from the active material coating part 31; the shell 10 can also be pushed toward the electrode assembly 30, so that the conductive part 32 passes through the through hole 211 and extends out of the battery cell 100 from the side of the pole 20 away from the active material coating part 31.

[0238] When preparing the battery cell 100, the end of the conductive portion 32 away from the active material coating portion 31 can be pushed to move toward the pole 20, so that the end of the conductive portion 32 away from the active material coating portion 31 extends out of the battery cell 100 from the side of the pole 20 away from the active material coating portion 31, and the extended portion of the conductive portion 32 is welded to the cover plate 40 on the outside of the battery cell 100. In this way, the damage to the battery cell 100 caused by the welding slag falling into the battery cell 100 during the welding process can be reduced; then, the cover plate 40 and the pole 20 are assembled, so that the cover plate 40 covers the end of the through hole 211 away from the active material coating portion 31, and the pole ear is bent and received in the through hole 211, and then the cover plate 40 is welded to the pole 20 to seal the battery cell 100.

[0239] According to the preparation method of the battery cell 100 of the present invention, the cover plate 40 and the conductive part 32 can be welded and connected on the outside of the battery cell 100. In this way, the damage to the battery cell 100 caused by the welding slag falling into the battery cell 100 during the welding process can be reduced, thereby improving the reliability of the battery cell 100; at the same time, the conductive part 32 can be accommodated in the through hole 211, thereby reducing the space occupied by the conductive part 32 inside the shell 10, so that the shell 10 can accommodate a larger volume of the active material coating part 31, thereby improving the energy density of the battery cell 100; in addition, the redundancy of the conductive part 32 can be reduced, further reducing the probability of short circuit between the conductive part 32 and the active material coating part 31, thereby increasing the stability of the battery cell 100.

[0240] In some specific embodiments of the present invention, before one end of the pole ear portion 321 passes through the through hole 211 of the pole 20 and extends out from the other side of the pole 20 , the preparation method further includes: connecting multiple pole ear sheets of the pole ear portion 321 into one by pre-welding.

[0241] Among them, a plurality of pole tab sheets are stacked to form a pole tab, and the plurality of pole tab sheets can be connected as a whole by ultrasonic pre-welding to form one end of the pole tab.

[0242] In this embodiment, the multiple pole tabs of the pole tab portion 321 are connected as one by pre-welding, which can reduce the gap between the pole tabs and make one end of the pole tab portion 321 more compact, thereby facilitating the subsequent extension of the pole tab portion 321 into the through hole 211 for operation.

[0243] According to some embodiments of the present invention, one end of the conductive part 32 is welded to the cover plate 40 on the other side of the pole 20, including: pressing the other end of the conductive part 32 onto a side surface of the cover plate 40; and laser welding the other end of the conductive part 32 to the cover plate 40.

[0244] It can be understood that after one end of the conductive part 32 away from the active material coating part 31 extends out of the through hole 211, the extended end of the conductive part 32 is first pressed and fitted to the boss 42 of the cover plate 40 to ensure the welding gap, and then the conductive part 32 and the cover plate 40 are laser welded by laser.

[0245] Among them, laser welding is an efficient and precise welding method that uses a high-energy-density laser beam as a heat source, which can achieve non-contact welding. Laser welding has the advantages of high precision, high speed, and small deformation. Therefore, the conductive part 32 and the cover plate 40 are laser welded, which can improve the connection speed of the conductive part 32 and the cover plate 40 and increase the welding quality of the conductive part 32 and the cover plate 40.

[0246] In this embodiment, the other end of the conductive part 32 is pressed onto the surface of one side of the cover plate 40 to ensure a welding gap, thereby realizing laser welding and improving welding quality. By utilizing laser welding between the conductive part 32 and the cover plate 40, the connection speed between the conductive part 32 and the cover plate 40 can be increased, thereby improving the welding quality between the conductive part 32 and the cover plate 40.

[0247] In some specific embodiments of the present invention, fixing the cover plate 40 to the pole 20 includes: welding the cover plate 40 to the pole 20 .

[0248] It can be understood that after the conductive part 32 and the cover plate 40 are laser welded, the cover plate 40 and the pole 20 are assembled. The cover plate 40 can be assembled into the groove 212 on the side of the pole 20 away from the electrode assembly 30, and then the cover plate 40 and the pole 20 are welded and connected to seal the end of the through hole 211 away from the active material coating part 31, and finally the assembly of the battery cell 100 is completed.

[0249] In this embodiment, the cover plate 40 is connected to the pole 20 by welding, so that the connection stability between the cover plate 40 and the pole 20 can be increased, and the sealing of the battery cell 100 can be increased, thereby improving the reliability of the battery cell 100.

[0250] The battery 1000 according to the third embodiment of the present invention comprises the battery cell 100 according to the first embodiment of the present invention.

[0251] In some specific embodiments of the present invention, for example Figure 2 As shown, the battery 1000 may further include: a main box 201 and an end cover 202 . The main box 201 has a cavity with an open top, and a plurality of battery cells 100 are disposed in the cavity. The end cover 202 is sealed on the top of the main box 201 by fasteners.

[0252] Optionally, a plurality of battery cells 100 may be stacked and arranged in the cavity along a thickness direction of the battery cells 100 .

[0253] Optionally, the main box 201 is formed in the shape of a rectangular box body, the inner side of the main box 201 defines a cavity, the top of the cavity is open, a plurality of first fixing holes are provided on the main box 201, the end cover 202 is formed in the shape of a horizontally arranged flat plate, the end cover 202 is provided with a plurality of second fixing holes that penetrate the end cover 202 in the up and down directions, the plurality of first fixing holes correspond to the plurality of second fixing holes one by one and are opposite to each other up and down, the battery 1000 also includes a plurality of fasteners, and the plurality of fasteners pass through the first fixing holes and the second fixing holes to fasten the end cover 202 to the upper side of the main box 201.

[0254] Optionally, the end cover 202 may be a carbon steel plate, an aluminum plate, or a composite material plate.

[0255] This embodiment can facilitate the loading of the battery cell 100 into the box body 200 by configuring the box body 200 as a main box 201 and an end cover 202 arranged separately. The main box 201 and the end cover 202 are connected by fasteners to achieve a detachable connection, which is convenient for maintenance and replacement, and can ensure the connection strength between the main box 201 and the end cover 202, thereby ensuring the overall structural strength of the battery 1000.

[0256] In some specific embodiments of the present invention, a first adhesive layer is provided on the bottom wall of the cavity, and the bottoms of the multiple battery cells 100 are connected to the bottom wall of the main box 201 through the first adhesive layer; and / or, a second adhesive layer is provided on the end cover 202, and the tops of the multiple battery cells 100 are connected to the end cover 202 through the second adhesive layer.

[0257] The battery 1000 may include only the first glue layer, or only the second glue layer, or may include both the first glue layer and the second glue layer. The first glue layer is used to bond the bottom wall of the main box 201 and the battery cell 100, and the second glue layer is used to bond the end cover 202 and the battery cell 100, so as to reliably fix multiple battery cells 100 in the box 200, improve the reliability and stability of the connection between the battery cell 100 and the box 200, and effectively prevent the battery cell 100 from shaking in the box 200.

[0258] In this embodiment, a first adhesive layer and a second adhesive layer are provided, and the bottom of the battery cell 100 is bonded and fixed to the bottom wall of the main box 201 through the first adhesive layer, and the top of the battery cell 100 is bonded and fixed to the end cover 202 through the second adhesive layer. In this way, the overall strength of the battery 1000 can be improved and the connection stability of the battery cell 100 can be ensured.

[0259] The battery 1000 according to the embodiment of the present invention is provided with the battery cell 100 of the embodiment of the first aspect, thereby improving the overall performance of the battery 1000.

[0260] The electric device according to the fourth embodiment of the present invention comprises the battery 1000 according to the third embodiment of the present invention, and the battery 1000 is used to provide electric energy.

[0261] The power-consuming device may be any of the aforementioned devices or systems using the battery 1000 .

[0262] According to the electric device of the embodiment of the present invention, the overall performance of the electric device is improved by providing the battery 1000 of the embodiment of the third aspect.

[0263] The following will refer to Figure 3-Figure 14 A battery cell 100 according to a specific embodiment of the present invention is described.

[0264] Reference Figure 3 The battery cell 100 includes a shell 10, a pole 20, a cover plate 40 and an electrode assembly 30. The shell 10 includes a first wall 11 and a receiving cavity. The pole 20 is arranged on the first wall 11 and has a through hole 211. The cover plate 40 is arranged on the side of the pole 20 away from the electrode assembly 30 and is welded to the pole 20 to cover the end of the through hole 211 away from the electrode assembly 30. The electrode assembly 30 is arranged in the receiving cavity. The electrode assembly 30 includes an active material coating part 31 and a conductive part 32, which is the core component of the battery cell 100.

[0265] Specifically, the active material coating part 31 is a pole piece of the electrode assembly 30, and the conductive part 32 is a pole ear of the electrode assembly 30. The pole piece includes a positive pole piece and a negative pole piece, and the pole piece includes a current collector and an active material layer disposed on the current collector. The pole ear includes a plurality of pole ear pieces, and the plurality of pole ear pieces converge at positions close to the current collector to form a first gathering part 3211, and the plurality of pole ear pieces converge at positions away from the current collector and are connected to form a second gathering part 3212, and the first gathering part 3211 connects the second gathering part 3212 and the active material coating part 31, and at least a portion of the second gathering part 3212 is accommodated in the through hole 211 and is welded to the cover plate 40.

[0266] The second gathering portion 3212 extends along the surface of the cover plate 40. In the direction from the electrode assembly 30 toward the cover plate 40, one end of the first gathering portion 3211 is connected to the active material coating portion 31, and the other end of the first gathering portion 3211 extends obliquely toward the peripheral wall of the through hole 211 and extends to connect with one end of the second gathering portion 3212 to form a "Z" shape.

[0267] The cover plate 40 includes a cover plate body 41 and a boss 42. The cover plate body 41 is used to cover one end of the through hole 211. The boss 42 is arranged on a side surface of the cover plate body 41 facing the electrode assembly 30 and extends into the through hole 211. The boss 42 and the through hole 211 are clearance-matched, and the conductive part 32 is connected to a side surface of the boss 42 facing the electrode assembly 30. The electrical connecting sheet 50 is connected to a side surface of the cover plate body 41 facing away from the electrode assembly 30.

[0268] Among them, the cover plate 40 also has a first welding area 43 and a second welding area 44, which are respectively formed on both sides of the center line of the cover plate 40 perpendicular to the length direction. The first welding area 43 is connected to the conductive part 32, and the second welding area 44 is connected to the electrical connecting piece 50. The first welding area 43 and the second welding area 44 are indirectly arranged, and the spacing between the first welding area 43 and the second welding area 44 is greater than or equal to 2 mm.

[0269] In addition, the thickness of the cover plate 40 is greater than or equal to 1.5 mm and less than or equal to 5 mm, the height of the boss 42 protruding from the surface of one side of the cover plate body 41 is 1.5 mm-3 mm, and the matching clearance between the boss 42 and the through hole 211 is less than or equal to 0.05 mm.

[0270] The pole 20 includes a pole body 21, a first ring 22 and a second ring 23, wherein the pole body 21 is annular and defines a through hole 211 on the inner side; the first ring 22 is integrally formed with the pole body 21 and is located in the accommodating cavity, the first ring 22 is arranged on the outer peripheral surface of the pole body 21, the surface of one side of the first ring 22 facing the electrode assembly 30 is flush with the surface of one side of the pole body 21 facing the electrode assembly 30 and the other side abuts against the inner wall of the shell 10, the second ring 23 is integrally formed with the pole body 21 and is located outside the shell 10, the second ring 23 is arranged on the outer peripheral surface of the pole body 21, the surface of one side of the second ring 23 facing away from the electrode assembly 30 is flush with the surface of one side of the pole body 21 facing away from the electrode assembly 30 and the other side abuts against the shell 10.

[0271] A groove 212 is formed on the side surface of the pole 20 facing away from the electrode assembly 30. In the direction from the electrode assembly 30 toward the cover plate 40, the side wall of the groove 212 extends outwardly and obliquely along the radial direction of the through hole 211. The through hole 211 is formed on the inner side of the groove 212 and passes through the bottom wall of the groove 212. The cover plate 40 is covered in the groove 212 to cover the through hole 211. The outer surface of the cover plate 40 is flush with the outer surface of the pole 20.

[0272] According to the battery cell 100 of the embodiment of the present invention, by providing the pole 20 with a through hole 211, and at least part of the conductive part 32 is provided in the through hole 211, the space occupied by the conductive part 32 inside the housing 10 can be reduced, so that the housing cavity of the housing 10 can accommodate a larger active material coating part 31, thereby improving the volume energy density of the battery cell 100. At the same time, the redundancy of the conductive part 32 in the housing 10 can be reduced, the probability of short circuit between the conductive part 32 and the active material coating part 31 can be reduced, and the probability of short circuit of the battery cell 100 can be reduced, thereby improving the working reliability and stability of the battery cell 100 and the battery 1000. In addition, by providing the through hole 211 inside the pole 20, the weight of the pole 20 can also be reduced, thereby improving the weight energy density of the battery cell 100 and the battery 1000.

[0273] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: A housing (10) comprising a first wall (11); A pole (20) disposed on the first wall (11) and having a through hole (211); A cover plate (40) is arranged on one side of the pole (20) and covers an end corresponding to the through hole (211); The electrode assembly (30) comprises an active material coating portion (31) and a conductive portion (32) connected to the active material coating portion (31), wherein the active material coating portion (31) is disposed in the shell (10), and at least a portion of the conductive portion (32) is disposed in the through hole (211) and connected to the cover plate (40).

2. The battery cell according to claim 1, characterized in that: The cover plate (40) is connected to the conductive part (32) by welding.

3. The battery cell according to claim 1, characterized in that: The cover plate (40) has a first welding area (43) and a second welding area (44); the first welding area (43) is welded to the conductive portion (32); the second welding area (44) is used to weld to the electrical connection sheet (50); and the first welding area (43) and the second welding area (44) are different areas of the cover plate (40).

4. The battery cell according to claim 3, characterized in that: The first welding area (43) and the second welding area (44) are respectively formed on two sides of a center line of the cover plate (40) that is perpendicular to the length direction or the width direction.

5. The battery cell according to claim 4, characterized in that: The spacing between the first welding area (43) and the second welding area (44) is less than or equal to two-thirds of the width of the cover plate (40), and / or the spacing between the first welding area (43) and the second welding area (44) is greater than or equal to one-third of the width of the cover plate (40).

6. The battery cell according to claim 3, characterized in that: The distance between the first welding area (43) and the second welding area (44) is greater than or equal to 2 mm.

7. The battery cell according to claim 3, characterized in that: The first welding area (43) and the conductive part (32) are welded together to form a first welding pool (431), and the second welding area (44) and the electrical connecting piece (50) are welded together to form a second welding pool (441), and the first welding pool (431) and the second welding pool (441) are arranged at intervals.

8. The battery cell according to claim 1, characterized in that: The ratio of the thickness of the cover plate (40) to the thickness of the first wall (11) is 1-4; optionally, the ratio of the thickness of the cover plate (40) to the thickness of the first wall (11) is 2-3; optionally, the thickness of the cover plate (40) is greater than or equal to 1.5 mm and less than or equal to 5 mm.

9. The battery cell according to any one of claims 1 to 8, characterized in that: The cover plate (40) comprises a cover plate body (41) and a boss (42), wherein the cover plate body (41) covers one end of the through hole (211), the boss (42) is arranged on a side surface of the cover plate body (41) facing the electrode assembly (30) and extends into the through hole (211), and the conductive portion (32) is connected to the boss (42).

10. The battery cell according to claim 9, characterized in that: The height of the boss (42) protruding from the one side surface of the cover plate body (41) is 1 mm-5 mm; optionally, 1.5 mm-3 mm.

11. The battery cell according to claim 9, characterized in that: The boss (42) is clearance-matched with the one end of the through hole (211), and the clearance between the boss (42) and the through hole (211) is 0-0.1 mm; optionally, the clearance between the boss (42) and the through hole (211) is less than or equal to 0.05 mm.

12. The battery cell according to claim 9, characterized in that: The pole (20) is a negative pole, the cover plate body (41) and the boss (42) are separate parts, and the cover plate body (41) and the boss (42) are made of different materials. The material of the boss (42) is the same as that of the conductive part (32); when the boss (42) and the conductive part (32) are welded, the depth of the molten pool on the cover plate (40) is less than the thickness of the boss (42).

13. The battery cell according to claim 9, characterized in that: The pole (20) is a positive pole, the boss (42) and the cover plate body (41) are integrally formed, and when the cover plate (40) and the conductive part (32) are welded, the depth of the molten pool on the boss (42) is greater than the thickness of the boss (42).

14. The battery cell according to any one of claims 1 to 8, characterized in that: The pole (20) is connected to the cover plate (40) by welding.

15. The battery cell according to any one of claims 1 to 8, characterized in that: The pole (20) is in the shape of a hollow ring and defines the through hole (211) on the inner side.

16. The battery cell according to any one of claims 1 to 8, characterized in that: The pole (20) comprises: A pole body (21), the pole body (21) being annular and defining the through hole (211) on its inner side; A first ring (22), the first ring (22) being connected to one end of the pole body (21) facing the electrode assembly (30), the first ring (22) extending radially outwards of the pole body (21) and extending circumferentially of the pole body (21) in a ring shape; A second ring (23), the second ring (23) is connected to the other end of the pole body (21) away from the electrode assembly (30), and the second ring (23) extends radially outwards of the pole body (21) and extends circumferentially of the pole body (21) in a ring shape.

17. The battery cell according to any one of claims 1 to 8, characterized in that: A groove (212) is formed on a surface of the pole (20) on one side facing away from the electrode assembly (30), the through hole (211) is formed on the inner side of the groove (212) and passes through the bottom wall of the groove (212), and the cover plate (40) is arranged in the groove (212).

18. The battery cell according to claim 17, characterized in that: In a direction from the electrode assembly (30) toward the cover plate (40), a side wall of the groove (212) extends outwardly and obliquely along the radial direction of the through hole (211).

19. The battery cell according to claim 17, characterized in that: A surface of one side of the cover plate (40) facing away from the electrode assembly (30) is flush with an end surface of one end of the pole (20) facing away from the electrode assembly (30).

20. The battery cell according to any one of claims 1 to 8, characterized in that: The active material coating portion (31) comprises a current collector and an active material layer disposed on the current collector, the conductive portion (32) comprises a pole ear portion (321) electrically connected to the current collector, the pole ear portion (321) comprises a plurality of pole ear sheets, the plurality of pole ear sheets converge at positions close to the current collector to form a first gathered portion (3211), the plurality of pole ear sheets converge at positions away from the current collector and are connected to form a second gathered portion (3212), the first gathered portion (3211) connects the second gathered portion (3212) and the active material coating portion (31), and at least a portion of the second gathered portion (3212) is accommodated in the through hole (211).

21. The battery cell according to claim 20, characterized in that: The conductive portion (32) is fixedly connected to the cover plate (40) via the second retracted portion (3212).

22. The battery cell according to claim 20, characterized in that: At least a portion of the first retracted portion (3211) is accommodated in the through hole (211).

23. The battery cell according to any one of claims 1 to 8, characterized in that: The active material coating portion (31) comprises a current collector and an active material layer disposed on the current collector, the conductive portion (32) comprises a pole ear portion (321) electrically connected to the current collector, the pole ear portion (321) comprises a plurality of pole ear sheets, the plurality of pole ear sheets converge at positions close to the current collector to form a first gathered portion (3211), the plurality of pole ear sheets converge at positions away from the current collector and are connected to form a second gathered portion (3212), the first gathered portion (3211) connects the second gathered portion (3212) and the active material coating portion (31); The conductive portion (32) further comprises an adapter plate, the adapter plate being connected to the second retracted portion (3212), the conductive portion (32) being electrically connected to the cover plate (40) via the adapter plate, and at least a portion of the adapter plate being accommodated in the through hole (211).

24. The battery cell according to claim 23, characterized in that: At least a portion of the second gathered portion (3212) is located in the through hole (211); or, The second gathering portion (3212) is entirely located in the through hole (211), and at least a portion of the first gathering portion (3211) is located in the through hole (211).

25. The battery cell according to claim 20, characterized in that: The second gathering portion (3212) extends along the surface of the cover plate (40), and in the direction from the electrode assembly (30) toward the cover plate (40), one end of the first gathering portion (3211) is connected to the active material coating portion (31), and the other end of the first gathering portion (3211) extends obliquely toward the peripheral wall of the through hole (211) and extends to be connected to one end of the second gathering portion (3212).

26. A method for preparing a battery monomer, characterized in that: The preparation method comprises: Passing one end of the conductive portion (32) through the through hole (211) of the pole (20) and extending out from the other side of the pole (20); The one end of the conductive portion (32) is welded to the cover plate (40) on the other side of the pole (20); The cover plate (40) is covered on one end of the through hole (211), and the conductive portion (32) is received in the through hole (211); The cover plate (40) is fixedly connected to the pole (20).

27. The method for preparing a battery cell according to claim 26, characterized in that: The step of welding the one end of the conductive portion (32) to the cover plate (40) on the other side of the pole (20) comprises: Pressing the other end of the conductive portion (32) onto a side surface of the cover plate (40); The other end of the conductive portion (32) is laser welded to the cover plate (40).

28. A battery, characterized in that: A battery cell comprising the battery cell according to any one of claims 1 to 25; or a battery cell prepared by the method for preparing a battery cell according to claim 26 or 27.

29. An electrical device, characterized in that: A battery according to claim 28, for providing electrical energy.

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