Battery unit and manufacturing method therefor, annular battery, battery module, and electrical device

Abstract

The present invention relates to the technical field of lithium batteries, and discloses a battery unit and a manufacturing method therefor, an annular battery, a battery module, and an electrical device. The battery unit comprises a battery casing, the battery casing comprising an outer casing wall and an inner casing wall arranged in the outer casing wall; a bare cell sleeved between the outer casing wall and the inner casing wall; a battery endcap which is at least arranged at one end of the battery casing; a busbar arranged between the bare cell and the battery endcap, the busbar being electrically connected to a tab of the bare cell; a first electric connecting member is arranged on a side surface of the busbar facing the battery endcap, and the first electric connecting member extends towards the battery endcap and is electrically connected to an electric connecting portion of the battery endcap. The solution facilitates the connection between the busbar and the electric connecting portion of the battery endcap.

Description

Battery cell and preparation method thereof, annular battery, battery module, and electrical equipment

[0001] This application is based on Chinese patent applications with application number 202311279366.2 and application date September 28, 2023 and application number 202322664475.8 and application date September 28, 2023, and claims the priority of these two Chinese patent applications. The entire contents of the two Chinese patent applications are hereby introduced into this application as a reference. Technical Field

[0002] The present invention belongs to the technical field of lithium batteries, and in particular relates to a battery cell and a preparation method thereof, a ring-shaped battery, a battery module, and electrical equipment. Background Art

[0003] As a new type of secondary cylindrical battery, lithium-ion batteries have the advantages of high energy density and power density, high operating voltage, light weight, small size, long cycle life, good safety, and green environmental protection. They have broad application prospects in portable appliances, power tools, large-scale energy storage, electric transportation power supply, etc.

[0004] Lithium batteries are categorized by their shape into prismatic and cylindrical. For cylindrical lithium batteries, during processing, a welding pin is inserted from the negative electrode side, and the positive electrode busbar is welded to the positive electrode electrical connection on the battery end cap. The welding position is located at the axial center of the battery. After welding, the negative electrode cover is installed to seal the battery. However, for batteries with a central hole, due to their hollow center structure, welding cannot be performed from the axial center, making it difficult to connect the busbar to the electrical connection position.

[0005] Summary of the Invention

[0006] The present invention provides a battery unit and a preparation method thereof, a ring-shaped battery, a battery module, and an electrical device, which at least improve the convenience of connecting the electrical connection portion between the busbar and the battery end cover.

[0007] In a first aspect, the present invention provides a battery cell, comprising:

[0008] A battery housing, the battery housing comprising an outer shell wall and an inner shell wall disposed within the outer shell wall;

[0009] A bare battery cell is sleeved between the outer shell wall and the inner shell wall;

[0010] a battery end cover, provided at least at one end of the battery housing;

[0011] A busbar is arranged between the bare battery cell and the battery end cover, and the busbar is electrically connected to the tabs of the bare battery cell; a first electrical connector is provided on the side of the busbar facing the battery end cover, and the first electrical connector extends toward the battery end cover and is electrically connected to the electrical connection part of the battery end cover.

[0012] As an implementation method, the first electrical connector includes a first annular electrical connection wall, and the first annular electrical connection wall is electrically connected to the electrical connection portion;

[0013] Alternatively, the first electrical connection member includes at least one of a first arc-shaped electrical connection wall and a first straight electrical connection wall, and the first arc-shaped electrical connection wall and / or the first straight electrical connection wall are electrically connected to the electrical connection portion.

[0014] As an implementation method, two or more first arc-shaped electrical connection walls are evenly spaced along the circumferential direction of the inner shell wall.

[0015] As an implementation manner, two or more first straight electrical connection walls are evenly spaced along the circumference of the inner shell wall.

[0016] As an implementation manner, in a structure in which the first electrical connector includes the first annular electrical connecting wall or the first arc-shaped electrical connecting wall, the first annular electrical connecting wall or the first arc-shaped electrical connecting wall is coaxially arranged with the inner shell wall.

[0017] As an implementation method, the electrical connection portion includes a second electrical connection piece extending toward the busbar, and the second electrical connection piece is circumferentially welded and fixed to the first annular electrical connection wall;

[0018] Alternatively, the second electrical connection member is fixed to the first arc-shaped electrical connection wall and / or the first straight electrical connection wall by welding along the circumferential direction.

[0019] As an implementation manner, the second electrical connection member at least partially overlaps and contacts the first annular electrical connection wall;

[0020] Alternatively, the second electrical connection member at least partially overlaps and contacts the first arc-shaped electrical connection wall and / or the first straight electrical connection wall.

[0021] As an implementation method, the second electrical connection piece is welded to the outer side surface or the inner side surface of the first annular electrical connection wall;

[0022] Alternatively, the second electrical connection member is welded to the outer side surface or the inner side surface of the first arc-shaped electrical connection wall and / or the first straight electrical connection wall.

[0023] As an implementation manner, the second electrical connector includes a second annular electrical connector wall, and the second annular electrical connector wall is electrically connected to the first electrical connector;

[0024] Alternatively, the second electrical connection member includes at least one of a second curved electrical connection wall and a second straight electrical connection wall, and the second curved electrical connection wall and / or the second straight electrical connection wall are electrically connected to the first electrical connection member.

[0025] As an implementation manner, in a structure where the second electrical connector includes the second annular electrical connecting wall or the second curved electrical connecting wall, the second annular electrical connecting wall or the second curved electrical connecting wall is coaxially arranged with the first annular electrical connecting wall, and the second annular electrical connecting wall or the second curved electrical connecting wall is matched with the side opposite to the first annular electrical connecting wall;

[0026] Alternatively, in a structure in which the second electrical connector includes the second annular electrical connecting wall or the second curved electrical connecting wall, the second annular electrical connecting wall or the second curved electrical connecting wall is coaxially arranged with the first curved electrical connecting wall, and the second annular electrical connecting wall or the second curved electrical connecting wall is matched with the side opposite to the first curved electrical connecting wall;

[0027] In the structure where the second electrical connector includes the second annular electrical connecting wall, the second arcuate electrical connecting wall or the second straight electrical connecting wall, the second straight electrical connecting wall is matched with the side surface opposite to the first straight electrical connecting wall.

[0028] As an implementation method, the electrical connection portion includes a groove arranged on the side of the battery end cover facing the bus, and the first annular electrical connection wall portion is fitted to the inner wall of the groove; or, the first arc-shaped electrical connection wall and / or the first straight electrical connection wall portion is fitted to the inner wall of the groove.

[0029] As an implementation manner, an insulating support is provided on the outer side of the inner shell wall, and the first electrical connector and the second electrical connector are both located on a side of the insulating support facing away from the inner shell wall.

[0030] As an implementation method, the insulating support member includes an insulating support ring, which is fixedly mounted on the inner shell wall and is used to support the welding position of the second electrical connector and the first electrical connector in the axial direction of the inner shell wall.

[0031] As an implementable manner, the busbar is provided with a flexibility enhancement structure, and the flexibility enhancement structure includes a through hole provided through the busbar.

[0032] As an implementation manner, the inner shell wall is provided with a hole, and the hole extends along the axis of the inner shell wall.

[0033] As an implementable manner, the hole is a heat dissipation hole.

[0034] As an implementation manner, the hole is a through hole or a blind hole.

[0035] As an implementation manner, the cross section of the hole is a circle, a regular polygon, an ellipse or a non-equilateral polygon.

[0036] As an implementable manner, the maximum straight-line distance between any two points on the hole cross section is 0.11-0.65 of the maximum straight-line distance between any two points on the shell wall cross section.

[0037] As an implementation manner, the cross section of the outer shell wall and / or the inner shell wall is a circle, a regular polygon, an ellipse or a non-equilateral polygon.

[0038] As an implementable manner, the cross section of the bare cell is a circle, a regular polygon, an ellipse or a non-equilateral polygon corresponding to the shape of the shell wall.

[0039] As an implementation method, the battery end cover is provided at one end of the battery shell, the end of the shell wall away from the battery end cover is closed, and at least one liquid injection port is provided at the end of the shell wall away from the battery end cover.

[0040] As an implementation method, an annular groove is provided at one end of the shell wall away from the battery end cover, and the liquid injection port is provided at the bottom of the annular groove; a sealing member is provided in the annular groove, and the sealing member is sealed with the liquid injection port.

[0041] As an implementation manner, the annular groove is coaxially arranged with the inner shell wall.

[0042] As an implementable manner, the battery end cover is provided with a pole, and the second electrical connector is bendable and has one end electrically connected to the pole.

[0043] As an implementation method, the second electrical connector further includes a bendable flexible connecting piece, wherein the flexible connecting piece is electrically connected to the pole and the second annular electrical connecting wall;

[0044] Alternatively, the second arc-shaped electrical connection wall and / or the second straight electrical connection wall may be bent.

[0045] As an implementation method, the battery end cover and the bus bar are provided at both ends of the battery shell, wherein the battery end cover at one end is provided with a positive electrode column electrically connected to its electrical connection part, and the battery end cover at the other end is provided with a negative electrode column electrically connected to its electrical connection part.

[0046] As an achievable method, one end of the battery shell is provided with the battery end cover and the bus, the battery end cover is provided with a pole electrically connected to its electrical connection part, the other end of the battery shell is closed, and the pole ear of the bare battery cell not connected to the bus is electrically connected to the other end of the battery shell through a collecting plate.

[0047] As an implementable manner, the battery unit further includes a cell inner ring sleeve, the cell inner ring sleeve including a main body portion and a limiting and pressing portion, both of which are insulated, the limiting and pressing portions being fixedly disposed at both ends of the main body portion and protruding from the end portion of the main body portion;

[0048] The main body is inserted into the hole in the middle of the bare battery core, and the limiting and pressing portion is pressed against the end surface of the bare battery core.

[0049] As an implementable manner, the portion where the position limiting and pressing portion is connected to the main body portion can be bent, and the position limiting and pressing portion is pressed against the end surface of the battery cell after being bent.

[0050] As an implementable manner, at least one of the position limiting and pressing portions is provided at an end portion of the main body portion.

[0051] As an implementable manner, a plurality of position-limiting and pressing portions are provided at the end portion of the main body, and the plurality of position-limiting and pressing portions are circumferentially arranged around the central axis of the main body.

[0052] As an implementable manner, the distance from the edge of the limiting and pressing portion to the central axis of the main body portion is less than or equal to the distance from the edge of the battery cell to the central axis of the battery cell.

[0053] As an implementable manner, the main body is a columnar structure, and the cross-sectional shape of the main body is circular, polygonal or racetrack-shaped.

[0054] As an implementable manner, the main body is in a cylindrical structure, and the cross-sectional shape of the main body is circular, polygonal or racetrack-shaped.

[0055] As an implementable manner, the main body and the limiting and pressing portion are an integrated structure.

[0056] As an implementation method, the end edge of the main body is provided with a bendable folded edge facing outward.

[0057] As an implementable manner, the position limiting and pressing portion is provided on the folded edge; or the position limiting and pressing portion is located on one side of the folded edge.

[0058] In a second aspect, the present invention provides a ring-shaped battery comprising the above-mentioned battery unit.

[0059] As an implementation manner, the outer shell wall and the inner shell wall are arranged to form a cavity for accommodating the bare battery cell, and the cross-sectional shape of the cavity is annular.

[0060] In a third aspect, the present invention provides a battery comprising the above-mentioned annular battery.

[0061] In a fourth aspect, the present invention provides a battery module comprising a plurality of annular batteries as described above, wherein the plurality of annular batteries are connected in series and / or in parallel; or comprising a plurality of the batteries described above, wherein the plurality of batteries are connected in series and / or in parallel.

[0062] In a fifth aspect, the present invention provides an electrical device comprising a plurality of annular batteries as described above; or, comprising a plurality of the batteries described above; or, comprising the battery module described above.

[0063] In a sixth aspect, the present invention provides a method for preparing the battery cell as described above, comprising the following steps:

[0064] A welding gap is formed between the battery end cover and the battery housing in the axial direction of the inner shell wall, and the first electrical connector is circumferentially welded to the electrical connection portion of the battery end cover through the welding gap;

[0065] After the first electrical connector is circumferentially welded to the electrical connection portion of the battery end cover, the battery end cover is welded to the end portion of the battery housing.

[0066] In the above scheme, since the first electrical connector is provided on the side of the busbar facing the battery end cover, and the first electrical connector extends toward the battery end cover to provide a connection margin of a certain length, during the process of electrically connecting the first electrical connector to the electrical connection portion of the battery end cover, a gap can be provided between the battery end cover and the battery shell, and the first electrical connector is electrically connected to the electrical connection portion of the battery end cover through the gap in the lateral direction of the battery shell, thereby improving the convenience of connecting the busbar and the electrical connection portion of the battery end cover. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Other features, objects and advantages of the present application will become more apparent upon reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0068] FIG1 is an exploded view of a battery cell (housing wall not shown) provided in an embodiment of the present invention;

[0069] FIG2 is a perspective view of a busbar provided in an embodiment of the present invention;

[0070] FIG3 is a perspective view of a busbar provided in another embodiment of the present invention;

[0071] FIG4 is a cross-sectional view of a battery cell provided in another embodiment of the present invention;

[0072] FIG5 is a cross-sectional view of a battery cell provided in another embodiment of the present invention;

[0073] FIG6 is a cross-sectional view of a battery cell provided in another embodiment of the present invention;

[0074] FIG7 is a cross-sectional view of a battery cell provided in another embodiment of the present invention;

[0075] FIG8 is a bottom view of FIG4;

[0076] FIG9 is a schematic structural diagram of an inner ring sleeve of a battery cell provided by an embodiment of the present invention;

[0077] FIG10 is a schematic structural diagram of a battery core inner ring sleeve inserted into a battery core according to an embodiment of the present invention;

[0078] FIG11 is a schematic structural diagram of another battery cell provided by an embodiment of the present invention;

[0079] FIG12 is a schematic structural diagram of another battery cell inner ring sleeve provided by an embodiment of the present invention;

[0080] FIG13 is a schematic structural diagram of a housing provided by an embodiment of the present invention.

[0081] Explanation of the accompanying drawings: Battery end covers 1, 6, second arc-shaped electrical connection wall 11, soft connecting piece 12, second annular electrical connection wall 13, laser 2, busbars 3, 5, first arc-shaped electrical connection wall 31, first annular electrical connection wall 32, battery cell inner ring sleeve 100, bare battery cell 200, battery shell 300, main body 110, limiting and pressing part 120, folded edge 130, outer surface 140, end 150 of the main body, through holes 33, 160, hole 210, outer shell wall 310, annular groove 3101, liquid filling port 3102, inner shell wall 320, hole 3201, insulating support 7. DETAILED DESCRIPTION

[0082] The present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the relevant invention and are not intended to limit the invention. It should also be noted that, for ease of description, only the portions relevant to the invention are shown in the accompanying drawings.

[0083] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0084] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms "a," "the," and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any or all possible combinations of one or more of the associated listed items.

[0085] As shown in at least FIG1 to FIG6 , the battery cell provided by the embodiment of the present invention includes:

[0086] The battery housing 300 includes an outer shell wall 310 and an inner shell wall 320 disposed within the outer shell wall 310 .

[0087] Generally, the battery housing 300 can be made of metal, such as steel, aluminum, and aluminum alloy, etc. On the one hand, it can protect the bare battery cell 200 disposed therein, and on the other hand, it can also serve as one of the poles of the battery unit, such as the negative pole or the positive pole.

[0088] The outer shell wall 310 and the inner shell wall 320 may both be annular structures. The inner shell wall 320 may have a centrally located hole 3201, as shown in at least FIG4 . The hole 3201 may be a through hole, or alternatively, as shown in FIG6 , the hole 3201 may be a blind hole. The hole may serve as a heat dissipation hole for dissipating heat.

[0089] In certain specific implementations, the outer shell wall 310 and the inner shell wall 320 can be a one-piece structure, such as formed by casting or stamping a metal plate. Alternatively, the outer shell wall 310 and the inner shell wall 320 can be a two-piece structure, where the two-piece structure refers to the outer shell wall 310 and the inner shell wall 320 being two separate components. For example, the inner shell wall 320 and the outer shell wall 310 can be connected together by welding. If the bottom of the outer shell wall 310 has a base plate, the inner shell wall 320 can be directly welded to the base plate of the outer shell wall 310, with the base plate of the outer shell wall 310 having a hole that communicates with the hole 3201. If the outer shell wall 310 is merely an annular wall, the inner shell wall 320 can be connected to the outer shell wall 310 via an end cap. For example, one end of the inner shell wall 320 can be welded to the end cap, which is then welded to one end of the outer shell wall 310. In this case, one end of the end cap can have a hole that communicates with the hole 3201 in the inner shell wall 320.

[0090] In this embodiment, specifically, the cross-section of the outer shell wall 310 may be a circle, a regular polygon, an ellipse, or a non-equilateral polygon. Correspondingly, the cross-section of the inner shell wall 320 may also be a circle, a regular polygon, an ellipse, or a non-equilateral polygon. The cross-section of the hole in the inner shell wall 320 may also be a circle, a regular polygon, an ellipse, or a non-equilateral polygon. The cross-section of the bare cell 200 may also be a circle, a regular polygon, an ellipse, or a non-equilateral polygon.

[0091] As an implementable manner, the maximum straight-line distance between any two points on the cross section of the hole 3201 is 0.11-0.65 of the maximum straight-line distance between any two points on the cross section of the shell wall 310 .

[0092] For example, but not limited to, the maximum straight-line distance between any two points on the cross-section of the hole 3201 is 5.15 mm, 5.3 mm, 6.25 mm, 7 mm, 8.66 mm, 13 mm, 15.35 mm, 18.7 mm, 19 mm, 22.9 mm, 24 mm, 28.4 mm, 29.46 mm, etc. The maximum straight-line distance between any two points on the cross-section of the hole 3201 can be determined according to actual needs, as long as the maximum straight-line distance between any two points on the cross-section of the hole 3201 is 0.11-0.65 of the maximum straight-line distance between any two points on the cross-section of the outer shell wall 310 of the battery casing 300. In addition, generally, the longer the battery cell, the larger the maximum straight-line distance between any two points on the cross-section of the hole 3201 can be. That is, the maximum straight-line distance between any two points on the cross-section of the hole 3201 is positively correlated with the length of the battery cell, thereby improving the heat dissipation effect on the battery cell.

[0093] The bare battery cell 200 is sleeved between the outer shell wall 310 and the inner shell wall 320 .

[0094] It should be noted that a cavity is formed between the outer shell wall 310 and the inner shell wall 320 , and the cross-sectional shape of the cavity is preferably annular. The cavity at least serves as an installation space for the bare battery cell 200 , and the bare battery cell 200 is located in the installation space.

[0095] The battery end cover 1 is at least provided at one end of the battery housing 300 .

[0096] Generally, the battery end cover 1 can be fixed to the battery housing 300 by welding.

[0097] The busbar 3 is arranged between the bare battery cell 200 and the battery end cover 1, and the busbar 3 is electrically connected to the tabs of the bare battery cell 200; the busbar 3 is provided with a first electrical connector on the side facing the battery end cover 1, and the first electrical connector extends toward the battery end cover 1 and is electrically connected to the electrical connection part of the battery end cover 1.

[0098] Among them, the bus 3 and the first electrical connector can be an integral structure, for example, the bus 3 and the first electrical connector of an integral structure are prepared by casting or other processing methods; or they can be a two-body structure, for example, the bus 3 and the first electrical connector that are independent of each other are welded together by welding or other methods.

[0099] In order to ensure the reliability of the electrical connection between the busbar 3 and the bare battery cell 200, it is preferred to weld and fix the busbar 3 and the pole ear of the bare battery cell 200. On the one hand, the electrical connection between the busbar 3 and the pole ear of the bare battery cell 200 is realized, and on the other hand, the fixed connection between the busbar 3 and the pole ear of the bare battery cell 200 is realized.

[0100] In the above scheme, since the first electrical connector is provided on the side of the busbar 3 facing the battery end cover 1, and the first electrical connector extends toward the battery end cover 1 to provide a connection margin of a certain length, during the process of electrically connecting the first electrical connector to the electrical connection portion of the battery end cover 1, a gap may be provided between the battery end cover 1 and the battery housing 300. Through the gap, the first electrical connector is electrically connected to the electrical connection portion of the battery end cover 1 in the lateral direction of the battery housing 300, thereby improving the convenience of connecting the busbar 3 to the electrical connection portion of the battery end cover 1.

[0101] As an implementation method, as shown in FIG3 , the first electrical connector includes a first annular electrical connection wall 32 , and the first annular electrical connection wall 32 is electrically connected to the electrical connection portion.

[0102] The first annular electrical connection wall 32 can be an annular metal ring. Under the premise of meeting the current transmission requirements, its wall thickness can be, for example, within 1 mm. The thickness here is only an example, and other thicknesses can also be used. As long as the first annular electrical connection wall 32 is electrically connected to the electrical connection portion, when the battery end cover 1 is pressed toward the battery housing 300, the first annular electrical connection wall 32 can be easily deformed so that the battery end cover 1 can contact the battery housing 300. Preferably, under the premise of meeting the electrical connection performance, the flexibility of the first annular electrical connection wall 32 is as high as possible, so that after the battery end cover 1 contacts the battery housing 300, it will not be pushed open by the first annular electrical connection wall 32, which is beneficial to the subsequent welding operation of the battery end cover 1 and the battery housing 300.

[0103] In addition to the structure including the first annular electrical connection wall 32 , the first electrical connection member may also have a structure including at least one of a first arc-shaped electrical connection wall 31 (as shown in FIG. 2 ) and a first straight electrical connection wall.

[0104] In a structure in which the first electrical connector includes the first arc-shaped electrical connection wall 31 , the first arc-shaped electrical connection wall 31 is electrically connected to the electrical connection portion.

[0105] In a structure in which the first electrical connector includes the first straight electrical connection wall, the first straight electrical connection wall is electrically connected to the electrical connection portion.

[0106] Preferably, the first arc-shaped electrical connection wall 31 and the first straight electrical connection wall can both be made of metal sheets with good flexibility.

[0107] As an implementation method, two or more first curved electrical connection walls 31 are evenly spaced along the circumference of the inner shell wall 320. By evenly spaced along the circumference of the inner shell wall 320, the uniformity of the force applied to the first curved electrical connection walls 31 after connection with the electrical connection portion can be improved, and the uniformity of current transmission can also be improved.

[0108] As an implementation, two or more first straight electrical connection walls may be evenly spaced along the circumference of the inner shell wall 320. By evenly spaced along the circumference of the inner shell wall 320, the uniformity of the force applied to the first straight electrical connection walls after connection with the electrical connection portion can be improved, and the uniformity of current transmission can also be improved.

[0109] It should also be noted that the first electrical connector referred to in this article includes the structure of the first annular electrical connecting wall 32, the first arc-shaped electrical connecting wall 31 or the first straight electrical connecting wall, all of which refer to the form of the first electrical connector before the battery end cover 1 is connected to the battery shell 300, before the first electrical connector is deformed due to the battery end cover 1 being pressed against the battery shell 300.

[0110] As an implementable manner, in a structure where the first electrical connector includes the first annular electrical connecting wall 32 or the first curved electrical connecting wall 31, the first annular electrical connecting wall 32 or the first curved electrical connecting wall 31 is coaxially arranged with the inner shell wall 320. By coaxially arranging the first annular electrical connecting wall 32 or the first curved electrical connecting wall 31 with the inner shell wall 320, during assembly, the battery cover 1 can be directly assembled to the battery shell 300 along the axis of the inner shell wall 320, without having to consider the need to adjust the assembly angle between the battery end cover 1 and the battery shell 300 when the first annular electrical connecting wall 32 or the first curved electrical connecting wall 31 is eccentrically arranged with the inner shell wall 320. Therefore, the difficulty of assembly is reduced, which helps to improve efficiency. In addition, it can also prevent the problem of reduced connection reliability between the first electrical connector and the electrical connection part due to deformation before the first electrical connector is connected to the electrical connection part or misalignment of the first electrical connector and the electrical connection part caused by an error in the assembly angle when the first annular electrical connection wall 32 or the first arc-shaped electrical connection wall 31 is eccentrically arranged with the inner shell wall 320, thereby preventing the occurrence of problems.

[0111] As an implementation manner, the electrical connection portion includes a second electrical connection piece extending toward the busbar 3 , and the second electrical connection piece is fixed to the first annular electrical connection wall 32 by welding along the circumferential direction.

[0112] For example, during the assembly process, the battery end cover 1 is brought close to the battery shell 300. At this time, the bare battery cell 200 connected to the bus bar 3 has been assembled into the battery shell 300, maintaining a certain gap between the battery end cover 1 and the battery shell 300, and making the second electrical connector contact the first annular electrical connecting wall 32, and then the second electrical connector and the first annular electrical connecting wall 32 are welded through the gap so that the two are welded and fixed together.

[0113] The welding referred to herein may be performed by laser welding, ultrasonic welding, resistance welding, electromagnetic welding, friction welding, electric resistance welding, and the like.

[0114] At least as shown in FIG. 4 , when laser welding is used, the laser 2 penetrates the gap to weld the second electrical connector and the first annular electrical connection wall 32 , so that the two are welded and fixed together.

[0115] In other examples, when the first electrical connection portion adopts the structure of the first arc-shaped electrical connection wall 31 and / or the first straight electrical connection wall, the second electrical connection member is circumferentially welded and fixed to the first arc-shaped electrical connection wall 31 and / or the first straight electrical connection wall.

[0116] The welding method of the second electrical connector and the first arc-shaped electrical connecting wall 31 and / or the first straight electrical connecting wall may be the same as the welding method of the second electrical connector and the first annular electrical connecting wall 32 .

[0117] As an achievable method, in order to improve the connection strength between the first electrical connector and the second electrical connector and reduce the contact resistance at the connection; when the first electrical connector adopts the first annular electrical connecting wall 32, the second electrical connector at least partially overlaps and contacts the first annular electrical connecting wall 32.

[0118] When the first electrical connector is the first curved electrical connector wall 31 and / or the first straight electrical connector wall, the second electrical connector at least partially overlaps and contacts the first curved electrical connector wall 31 and / or the first straight electrical connector wall.

[0119] The welding position for the above-mentioned welding fixation is located in the overlapping area, that is, the first electrical connector and the second electrical connector are at least partially stacked and welded together.

[0120] As an implementation manner, the second electrical connection member is welded to the outer side surface or the inner side surface of the first annular electrical connection wall 32 .

[0121] 4 , the second electrical connector is welded to the inner side of the first annular electrical connection wall 32 ; and in FIG. 5 , FIG. 6 , and FIG. 7 , the second electrical connector is welded to the outer side of the first annular electrical connection wall 32 .

[0122] When the first electrical connector is a first arc-shaped electrical connecting wall 31 and / or a first straight electrical connecting wall, the second electrical connector is welded to the outer side surface or the inner side surface of the first arc-shaped electrical connecting wall 31 and / or the first straight electrical connecting wall.

[0123] As an implementation manner, the second electrical connector includes a second annular electrical connecting wall 13 , and the second annular electrical connecting wall 13 is electrically connected to the first electrical connector.

[0124] Specifically, in the structure where the second electrical connector includes the second annular electrical connecting wall 13 , the second annular electrical connecting wall 13 is coaxially arranged with the first annular electrical connecting wall 32 , and the second annular electrical connecting wall 13 and the first annular electrical connecting wall 32 have opposite sides that fit together.

[0125] In one example, the first annular electrical connecting wall 32 fits over the outside of the second annular electrical connecting wall 13 . In another example, the second annular electrical connecting wall 13 fits over the outside of the first annular electrical connecting wall 32 .

[0126] In addition to adopting a structure including a second annular electrical connecting wall 13, the second electrical connecting member may also include at least one of a second arcuate electrical connecting wall 11 and a second straight electrical connecting wall, and the second arcuate electrical connecting wall 11 and / or the second straight electrical connecting wall are electrically connected to the first electrical connecting member.

[0127] In the structure where the second electrical connector includes the second arcuate electrical connecting wall 11 , the second arcuate electrical connecting wall 11 is coaxially arranged with the first annular electrical connecting wall 32 , and the second arcuate electrical connecting wall 11 and the first annular electrical connecting wall 32 have opposite sides that match each other.

[0128] In one example, the second arc-shaped electrical connection wall 11 is arranged on the outside of the first annular electrical connection wall 32 and fits with its outer side surface. In another example, the second arc-shaped electrical connection wall 11 is arranged on the inside of the first annular electrical connection wall 32 and fits with its inner side surface.

[0129] In a structure in which the second electrical connector includes a second flat electrical connection wall, the second flat electrical connection wall is matched with the side surface opposite to the first flat electrical connection wall.

[0130] As another possible implementation, the electrical connection portion includes a groove provided on the side of the battery end cap 1 facing the busbar 3, wherein one end of the first electrical connector is located in the groove. Specifically, in a structure in which the first electrical connector includes the first annular electrical connection wall 32, the first annular electrical connection wall 32 partially adheres to the inner wall of the groove; in a structure in which the first electrical connector includes the first curved electrical connection wall 31, the first curved electrical connection wall 31 partially adheres to the inner wall of the groove; in a structure in which the first electrical connector includes the first straight electrical connection wall, the first straight electrical connection wall partially adheres to the inner wall of the groove. Subsequently, the first annular electrical connection wall 32, the first curved electrical connection wall 31, or the first straight electrical connection wall is welded to the inner wall of the groove using a welding needle.

[0131] As an implementation, referring to at least any one of Figures 4 to 7 , an insulating support member 7 is provided on the outer side of the inner shell wall 320, and the first and second electrical connectors are both located on the side of the insulating support member 7 facing away from the inner shell wall 320. The provision of the insulating support member 7 can, on the one hand, prevent a short circuit between the inner shell wall 320 and the first and second electrical connectors, and on the other hand, support the first and second electrical connectors in a radial direction of the inner shell wall 320 to facilitate electrical connection between the first and second electrical connectors.

[0132] As an implementation method, the insulating support member 7 includes an insulating support ring, which is fixedly mounted on the inner shell wall 320 and is used to support the welding position of the second electrical connector and the first electrical connector in the axial direction of the inner shell wall 320.

[0133] For example, the welding position of the second electrical connector and the first electrical connector is supported by an insulating support ring so that the welding positions of the second electrical connector and the first electrical connector are in contact with each other, so that the two are firmly welded together.

[0134] As an implementable manner, the battery end cover 1 is provided with a pole, and the second electrical connector is bendable and one end of the second electrical connector is electrically connected to the pole.

[0135] Generally, the pole and the battery end cover 1 are in an insulating state.

[0136] The second electrical connector being bendable here means that, during the process of the battery end cover 1 being covered on the battery housing 300 , as the battery end cover 1 gradually moves toward the battery housing 300 , the battery end cover 1 presses the second electrical connector to bend.

[0137] As an achievable method, as shown in any one of Figures 4 to 7, in order to improve the deformation ability, the second electrical connector also includes a bendable soft connecting piece 12, and the soft connecting piece 12 is electrically connected to the pole and the second annular electrical connecting wall 13; in the process of the battery end cover 1 being covered on the battery housing 300, as the battery end cover 1 gradually moves toward the battery housing 300, the battery end cover 1 at least presses the soft connecting piece 12 to bend.

[0138] In other examples, the second curved electrical connection wall 11 and / or the second straight electrical connection wall can be bent. Similarly, when the battery end cover 1 is attached to the battery housing 300, as the battery end cover 1 gradually moves toward the battery housing 300, the battery end cover 1 presses the second curved electrical connection wall 11 and / or the second straight electrical connection wall to bend.

[0139] As an implementation method, the battery end covers 1, 6 and the bus bars 3, 5 are provided at both ends of the battery housing 300, wherein the battery end cover 1 at one end is provided with a positive electrode column electrically connected to its electrical connection part, and the battery end cover 1 at the other end is provided with a negative electrode column electrically connected to its electrical connection part.

[0140] As an achievable method, one end of the battery shell 300 is provided with the battery end cover 1 and the bus 3, the battery end cover 1 is provided with a pole electrically connected to its electrical connection part, the other end of the battery shell 300 is closed, and the tab of the bare battery cell 200 that is not connected to the bus 3 is electrically connected to the other end of the battery shell 300 through a collecting plate.

[0141] As an implementable method, referring to FIG3 , in order to improve the reliability of welding between the busbar 3 and the tab of the bare cell 200 and avoid the problem of cold welding, a flexible structure is provided on the busbar 3, and the flexible structure includes a through hole 33 provided through the busbar 3. By providing the flexible structure, the rigidity of the busbar 3 is reduced and the busbar 3 becomes soft, so that during the welding process between the busbar 3 and the bare cell 200, the busbar 3 can fit snugly on the end face of the tab of the bare cell 200.

[0142] As a feasible method, at least referring to FIG8 , as described above, the first electrical connector and the second electrical connector are connected by welding. In order to avoid the adverse effect of the liquid injection port on the welding during the welding process, the battery end cover 1 is provided at one end of the battery shell 300, and the end of the outer shell wall 310 facing away from the battery end cover 1 is closed, and at least one liquid injection port 3102 is provided at the end of the outer shell wall 310 facing away from the battery end cover 1.

[0143] As an implementation method, an annular groove 3101 is provided at one end of the shell wall 310 away from the battery end cover 1, and the liquid injection port 3102 is provided at the bottom of the annular groove 3101; a sealing member is provided in the annular groove 3101, and the sealing member is sealed with the liquid injection port 3102.

[0144] For example, the number of the liquid injection ports 3102 can be set according to actual needs. In this example, four liquid injection ports 3102 are evenly arranged at the bottom of the annular groove.

[0145] As an implementation manner, the annular groove 3101 is coaxially arranged with the inner shell wall 320 .

[0146] As an achievable method, referring to Figures 9 and 10 , the battery unit further includes a cell inner ring sleeve 100, which includes a main body portion 110 and a limiting and pressing portion 120 that are both insulated. The limiting and pressing portion 120 is fixedly arranged at both ends of the main body portion 110 and protrudes from the end portion of the main body portion 110; the main body portion 110 can be passed through the hole 210 in the middle of the bare cell 200, and the limiting and pressing portion 120 can be pressed against the end surface of the bare cell 200.

[0147] After the bare battery cell 200 is wound, the middle part is in a suspended state. The battery cell inner ring sleeve 100 provided in the embodiment of the present invention supports the bare battery cell 200 by inserting the battery cell inner ring sleeve 100 into the hole 210 of the bare battery cell 200, thereby preventing the middle part of the bare battery cell 200 from collapsing. When the bare battery cell 200 forms a ring-shaped battery with a middle through hole, the bare battery cell 200 and the battery cell inner ring sleeve 100 are sleeved on the battery shell 300 together to prevent the bare battery cell 200 from being scratched during the sleeve installation process. The battery cell inner ring sleeve 100 is an insulating structure to avoid affecting the use of the battery. The limiting and pressing part 120 provided at the end of the battery cell inner ring sleeve 100 can prevent the battery cell inner ring sleeve 100 from falling off. The structure is simple and easy to use.

[0148] In an embodiment of the present application, the bare cell 200 is a wound cell, and the bare cell 200 is formed by stacking and winding the first electrode sheet, the diaphragm and the second electrode sheet in sequence to form an electrode unit of the bare cell 200, that is, the electrode unit is a wound structure, wherein the first electrode sheet, the diaphragm and the second electrode sheet need to be wound by a winding needle during the winding process, so the wound structure formed after the winding is completed will form a hole 210 that passes through the end face 150 at both ends of the main body.

[0149] In an embodiment of the present application, the hole 210 of the bare cell 200 can be a mounting hole on a wound structure forming a ring-shaped battery, or a heat dissipation hole on a wound structure forming a cylindrical battery or a square battery, and can be adjusted as needed in different embodiments.

[0150] In this embodiment, the portion where the limiting and pressing portion 120 is connected to the main body portion 110 can be bent, and after being bent, the limiting and pressing portion 120 is pressed against the end surface of the bare battery cell 200 to support the bare battery cell 200 and prevent the middle position of the bare battery cell 200 from collapsing, thereby ensuring the quality of the bare battery cell.

[0151] In the present application, the shape of the main body 110 of the battery cell inner ring 100 may vary depending on the type of battery. For example, for a square battery or a cylindrical battery, the main body 110 may be cylindrical; for a toroidal battery, the main body 110 may be cylindrical, which facilitates the battery cell inner ring 100 passing through the hole 210. In the embodiments of the present application, the sizes of the hole 210 and the main body 110 are not limited and may be set as needed in different embodiments.

[0152] After the bare battery cell 200 is wound, the winding needle is pushed out, and the position of the hole 210 can be supported by the cylinder. When the battery cell inner ring sleeve 100 is placed in the hole 210 of the bare battery cell 200, it can be understood that the wound bare battery cell has a certain elasticity, and the inner diameter of the hole 210 matches the outer diameter of the main body 110. In different embodiments, the inner diameter of the hole 210 can be greater than, equal to, or smaller than the outer diameter of the main body 110, which is not limited in the embodiments of the present application.

[0153] In this embodiment, the outer surface 140 of the main body 110 can be directly attached to the innermost diaphragm of the bare cell 200. In this embodiment of the present application, the inner ring 100 of the cell is an insulating structure. The inner ring 100 of the cell made of insulating material can avoid affecting the use of the battery, and can also reduce the risk of battery short circuit and improve the battery life.

[0154] In the embodiment of the present application, the material of the battery cell inner ring 100 is a polyester polymer with certain flexibility, elasticity, and hardness, good heat resistance, and insulation ability, such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyarylate (PAR).

[0155] Depending on the winding method of the bare cell 200, the bare cell 200 can be circular or racetrack-shaped, and the shape of the formed hole 210 can also be circular, polygonal, or racetrack-shaped (as shown in FIG11 ). In the present application, the cross-sectional shape of the outer surface 140 of the main body 110 in the direction parallel to the end 150 of the main body 110 is circular, polygonal, or racetrack-shaped (as shown in FIG12 ).

[0156] It should be noted that the runway shape is a flat long strip shape, that is, the runway shape has a certain length and a certain width, and the length dimension is greater than the width dimension. The winding shape of the bare battery cell 200 is a runway shape, so that the bare battery cell 200 has a plane set along the length direction. Compared with the circular winding shape, the plane can facilitate the winding of the bare battery cell 200, forming a more compact wound bare battery cell 200, avoiding loose structure while improving the overall force balance of the bare battery cell 200, and improving the battery life.

[0157] In different embodiments, the shape of the bare battery cell 200 can also be other shapes. In different embodiments, the shape of the battery cell inner ring sleeve 100 can be adjusted according to the different shapes of the holes 210 formed in the bare battery cell 200. This application does not limit this.

[0158] In the embodiment of the present application, the inner ring sleeve 100 of the battery cell also has a certain hardness, which can facilitate the insertion of the inner ring sleeve 100 of the battery cell into the hole 210, and at the same time enable the inner ring sleeve 100 of the battery cell to achieve stable supporting force when inserted on the bare battery cell 200, thereby avoiding the occurrence of local edge collapse of the bare battery cell 200; in addition, it also has the function of preventing the battery from being scratched, and protects the electrode to a certain extent.

[0159] Optionally, the main body 110 and the limiting and pressing portion 120 are an integrated structure.

[0160] It is understood that the main body 110 and the position-limiting and pressing portion 120 can be integrally formed or separately provided. When the main body 110 and the position-limiting and pressing portion 120 are separately provided, the main body 110 and the position-limiting and pressing portion 120 can be connected together by bonding, and the configuration can be adjusted as needed in different embodiments. In the embodiment of the present application, the integral structure can facilitate molding and improve the connection strength between the main body 110 and the position-limiting and pressing portion 120.

[0161] The main body 110 includes two oppositely arranged end portions 150, and each end portion 150 of the main body 110 is provided with at least one limiting and clamping portion 120, and the distance from the edge of each limiting and clamping portion 120 to the center of the main body 110 is less than or equal to the distance from the edge of the bare battery cell 200 to the center of the hole 210.

[0162] The limiting and pressing part 120 has a certain degree of flexibility and hardness. When the inner ring sleeve 100 of the battery cell is inserted into the hole 210, the limiting and pressing part 120 is in a non-bent state. After the inner ring sleeve 100 of the battery cell is inserted into the hole 210, the limiting and pressing part 120 bends from the end 150 of the main body 110 where it is located toward the end 150 of the other main body 110, for example, it is tightly pressed against the end surface of the bare battery cell 200; after the insertion is completed, the limiting and pressing part 120 is folded onto the end 150 of the main body 110. In addition, the limiting and pressing part 120 has a certain degree of hardness, which can play a blocking and limiting role to prevent the inner ring sleeve 100 of the battery cell from falling off from the bare battery cell 200. By limiting the protruding length of the limiting and pressing part 120 relative to the outer surface 140, by limiting the limiting and pressing part 120 not to exceed the outer diameter of the bare battery cell 200, it is prevented from affecting the installation of other positions of the bare battery cell 200.

[0163] Optionally, a plurality of position-limiting and pressing portions 120 are provided on the end portion 150 of each main body portion 110, and the plurality of position-limiting and pressing portions 120 are circumferentially arranged around the central axis of the main body portion 110. For example, the plurality of position-limiting and pressing portions 120 are radially arranged around the center of the main body portion 110. The plurality of position-limiting and pressing portions 120 can improve the blocking and limiting capabilities, and the number of the position-limiting and pressing portions 120 is not limited in the embodiments of the present application.

[0164] Optionally, both ends of the main body 110 are further fixedly provided with folded edges 130 disposed around the outer surface 140. The folded edges 130 protrude from the outer surface 140 and are bendable structures, and the position-limiting and pressing portion 120 is disposed on the folded edges 130. The folded edges 130 can be integrated with the position-limiting and pressing portion 120 and the main body 110 to simplify manufacturing; the distance from the edge of the folded edge 130 to the center of the main body 110 is less than the distance from the edge of the position-limiting and pressing portion 120 to the center of the main body 110.

[0165] Optionally, the folded edge 130 is a bendable structure, and the folded edge 130 has a certain degree of flexibility and hardness, which makes it easy to fold it onto the end surface of the bare battery cell 200. At this time, the folded edge 130 can also play a blocking and limiting role like the limiting and pressing part 120. That is to say, when the inner ring sleeve 100 of the battery cell is inserted into the hole 210, the folded edge 130 is in a non-bent state. After the inner ring sleeve 100 of the battery cell is inserted into the hole 210, the folded edge 130 bends from the end 150 of the main body 110 in which it is located toward the end 150 of the other main body 110, and then presses tightly against the end surface of the bare battery cell 200 to further limit and block the bare battery cell 200.

[0166] Optionally, the position-limiting and pressing portion 120 is provided on the folded edge 130; or the position-limiting and pressing portion 120 is located on one side of the folded edge 130. In different embodiments, the position of the position-limiting and pressing portion 120 is adjusted as required.

[0167] In an embodiment of the present application, the main body 110 includes a through hole 160 that passes through the two ends 150 of the main body 110, and the cross-sectional shape of the through hole 160 in the direction parallel to the end 150 of the main body 110 is circular or runway-shaped. By providing a through hole 160 on the inner ring sleeve 100 of the battery cell, when the battery is a toroidal battery, that is, the toroidal battery includes an annular shell 200, the annular shell 200 includes an outer shell wall 310 and an inner shell wall 320 arranged inside the outer shell wall 310, and an annular chamber is formed between the outer shell wall 310 and the inner shell wall 320. The inner ring sleeve 100 of the battery cell is sleeved on the inner shell wall 320 through the through hole 160, and the bare battery cell 200 and the inner ring sleeve 100 of the battery cell are placed in the annular chamber. The inner ring sleeve 100 of the battery cell has a certain hardness and has the function of preventing the battery from being scratched, and protects the inner pole piece to a certain extent.

[0168] In a second aspect, the present invention provides a ring-shaped battery comprising the above-mentioned battery unit.

[0169] As an implementation method, the outer shell wall 310 and the inner shell wall 320 are arranged to form a cavity for accommodating the bare battery cell 200 , and the cross-section of the cavity is annular.

[0170] In a third aspect, the present invention provides a battery, including the above-mentioned annular battery, so as to achieve better heat dissipation of the middle portion of the battery through the heat dissipation holes.

[0171] In a fourth aspect, the present invention provides a battery module comprising a plurality of annular batteries as described above, wherein the plurality of annular batteries are connected in series and / or in parallel; or comprising a plurality of the batteries described above, wherein the plurality of batteries are connected in series and / or in parallel.

[0172] The number of batteries to be used and their series-parallel relationship can be determined based on the output voltage and capacity of the battery module.

[0173] In a fifth aspect, the present invention provides an electrical device comprising a plurality of annular batteries as described above; or, comprising a plurality of the batteries described above; or, comprising the battery module described above.

[0174] Electrical equipment includes, but is not limited to, new energy vehicles (electric vehicles, hybrid vehicles, etc.), digital products, etc.

[0175] In a sixth aspect, the present invention provides a method for preparing the battery cell as described above, comprising the following steps:

[0176] S10: forming a welding gap between the battery end cover 1 and the battery housing 300 in the axial direction of the inner shell wall 320, and circumferentially welding the first electrical connector to the electrical connection portion of the battery end cover 1 through the welding gap;

[0177] S20 : ​​After the first electrical connector is circumferentially welded to the electrical connection portion of the battery end cover 1 , the battery end cover 1 is welded to the end of the battery housing 300 .

[0178] It should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like used above to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0179] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the inventive concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A battery cell, characterized in that: include: A battery housing, the battery housing comprising an outer shell wall and an inner shell wall disposed inside the outer shell wall; A bare battery cell, sleeved between the outer shell wall and the inner shell wall; A battery end cover, disposed at least at one end of the battery housing; A busbar is arranged between the bare battery cell and the battery end cover, and the busbar is electrically connected to the tabs of the bare battery cell; a first electrical connector is arranged on the side of the busbar facing the battery end cover, and the first electrical connector extends toward the battery end cover and is electrically connected to the electrical connection part of the battery end cover.

2. The battery cell according to claim 1, characterized in that: The first electrical connector includes a first annular electrical connection wall, and the first annular electrical connection wall is electrically connected to the electrical connection portion; Alternatively, the first electrical connection member includes at least one of a first arc-shaped electrical connection wall and a first straight electrical connection wall, and the first arc-shaped electrical connection wall and / or the first straight electrical connection wall are electrically connected to the electrical connection portion.

3. The battery cell according to claim 2, characterized in that: More than two first arc-shaped electrical connection walls are evenly spaced along the circumferential direction of the inner shell wall.

4. The battery cell according to claim 2, characterized in that: More than two first straight electrical connection walls are evenly spaced along the circumferential direction of the inner shell wall.

5. The battery cell according to claim 2, characterized in that: In a structure in which the first electrical connector includes the first annular electrical connecting wall or the first arc-shaped electrical connecting wall, the first annular electrical connecting wall or the first arc-shaped electrical connecting wall is coaxially arranged with the inner shell wall.

6. The battery cell according to any one of claims 2 to 5, characterized in that: The electrical connection portion includes a second electrical connection piece extending toward the bus bar, and the second electrical connection piece is circumferentially welded and fixed to the first annular electrical connection wall; Alternatively, the second electrical connection member is fixedly welded to the first arc-shaped electrical connection wall and / or the first straight electrical connection wall along the circumferential direction.

7. The battery cell according to claim 6, characterized in that: The second electrical connection member at least partially overlaps and contacts the first annular electrical connection wall; Alternatively, the second electrical connection member at least partially overlaps and contacts the first arc-shaped electrical connection wall and / or the first straight electrical connection wall.

8. The battery cell according to claim 7, characterized in that: The second electrical connection member is welded to the outer side surface or the inner side surface of the first annular electrical connection wall; Alternatively, the second electrical connection member is welded to the outer side surface or the inner side surface of the first arc-shaped electrical connection wall and / or the first straight electrical connection wall.

9. The battery cell according to claim 8, characterized in that: The second electrical connection member comprises a second annular electrical connection wall, and the second annular electrical connection wall is electrically connected to the first electrical connection member; Alternatively, the second electrical connection member includes at least one of a second arc-shaped electrical connection wall and a second straight electrical connection wall, and the second arc-shaped electrical connection wall and / or the second straight electrical connection wall are electrically connected to the first electrical connection member.

10. The battery cell according to claim 9, characterized in that: In the structure where the second electrical connector includes the second annular electrical connecting wall or the second arcuate electrical connecting wall, the second annular electrical connecting wall or the second arcuate electrical connecting wall is coaxially arranged with the first annular electrical connecting wall, and the second annular electrical connecting wall or the second arcuate electrical connecting wall is matched with the side opposite to the first annular electrical connecting wall; Alternatively, in a structure in which the second electrical connector includes the second annular electrical connecting wall or the second arcuate electrical connecting wall, the second annular electrical connecting wall or the second arcuate electrical connecting wall is coaxially arranged with the first arcuate electrical connecting wall, and the second annular electrical connecting wall or the second arcuate electrical connecting wall is matched with the side opposite to the first arcuate electrical connecting wall; The second electrical connection member includes the second annular electrical connection wall, the second arc In the structure of the electrical connection wall or the second straight electrical connection wall, the second straight electrical connection wall is matched with the side surface opposite to the first straight electrical connection wall.

11. The battery cell according to any one of claims 2 to 5, characterized in that: The electrical connection portion includes a groove arranged on the side of the battery end cover facing the bus bar, and the first annular electrical connection wall portion is in contact with the inner wall of the groove; or, the first arc-shaped electrical connection wall and / or the first straight electrical connection wall portion is in contact with the inner wall of the groove.

12. The battery cell according to claim 10, characterized in that An insulating support is disposed on the outer side of the inner shell wall, and the first electrical connector and the second electrical connector are both located on a side of the insulating support facing away from the inner shell wall.

13. The battery cell according to claim 12, characterized in that: The insulating support member includes an insulating support ring, which is fixedly mounted on the inner shell wall and used to support the welding position of the second electrical connector and the first electrical connector in the axial direction of the inner shell wall.

14. The battery cell according to any one of claims 1 to 5, characterized in that: The busbar is provided with a flexibility enhancement structure, and the flexibility enhancement structure includes a through hole penetrating the busbar.

15. The battery cell according to any one of claims 1 to 5, characterized in that: The inner shell wall is provided with a hole extending along the axis of the inner shell wall.

16. The battery cell according to claim 15, characterized in that The holes are heat dissipation holes.

17. The battery cell according to claim 15, characterized in that The hole is a through hole or a blind hole.

18. The battery cell according to claim 15, characterized in that The cross section of the hole is a circle, a regular polygon, an ellipse or a non-equilateral polygon.

19. The battery cell according to claim 15, characterized in that The maximum value of the straight-line distance between any two points on the cross section of the hole is 0.11-0.65 of the maximum value of the straight-line distance between any two points on the cross section of the shell wall.

20. The battery cell according to any one of claims 1 to 5, characterized in that: The cross section of the outer shell wall and / or the inner shell wall is a circle, a regular polygon, an ellipse or a non-equilateral polygon.

21. The battery cell according to claim 19, characterized in that The cross section of the bare battery core is a circle, a regular polygon, an ellipse or a non-equilateral polygon corresponding to the shape of the shell wall.

22. The battery cell according to any one of claims 1 to 5, characterized in that: The battery end cover is disposed at one end of the battery shell, the end of the shell wall away from the battery end cover is closed, and at least one liquid injection port is disposed at the end of the shell wall away from the battery end cover.

23. The battery cell according to claim 22, characterized in that An annular groove is arranged at one end of the shell wall away from the battery end cover, and the liquid injection port is arranged at the bottom of the annular groove; a sealing member is arranged in the annular groove, and the sealing member is in sealing cooperation with the liquid injection port.

24. The battery cell according to claim 23, characterized in that The annular groove is coaxially arranged with the inner shell wall.

25. The battery cell according to claim 9, characterized in that The battery end cover is provided with a pole, and the second electrical connector can be bent and one end of the second electrical connector is electrically connected to the pole.

26. The battery cell according to claim 25, characterized in that The second electrical connector also includes a bendable soft connection sheet, and the soft connection sheet is electrically connected to the pole and the second annular electrical connection wall; Alternatively, the second arc-shaped electrical connection wall and / or the second straight electrical connection wall may be bent.

27. The battery cell according to any one of claims 1 to 5, characterized in that: The battery end cover and the busbar are provided at both ends of the battery housing, wherein the battery end cover at one end is provided with a positive pole electrically connected to its electrical connection part, and the battery end cover at the other end is provided with a negative pole electrically connected to its electrical connection part.

28. The battery cell according to any one of claims 1 to 5, characterized in that: One end of the battery shell is provided with the battery end cover and the bus, and the battery end cover is provided with a pole electrically connected to its electrical connection part. The other end of the battery shell is closed, and the pole ear of the bare battery cell not connected to the bus is electrically connected to the other end of the battery shell through a collecting plate.

29. The battery cell according to any one of claims 1 to 5, characterized in that: It also includes an inner ring sleeve of the battery core, the inner ring sleeve of the battery core includes a main body portion and a limiting and pressing portion, both of which are insulated, and the limiting and pressing portion is fixedly arranged at both ends of the main body portion and protrudes from the end of the main body portion; The main body is inserted into the hole in the middle of the bare battery core, and the limiting and pressing part is pressed against the end surface of the bare battery core.

30. The battery cell according to claim 29, characterized in that The portion where the position limiting and pressing portion is connected to the main body portion can be bent, and the position limiting and pressing portion is pressed against the end surface of the battery cell after being bent.

31. The battery cell according to claim 29, characterized in that At least one of the position limiting and pressing parts is disposed at the end of the main body.

32. The battery cell according to claim 31, characterized in that A plurality of position limiting and pressing parts are arranged at the end of the main body, and the plurality of position limiting and pressing parts are circumferentially arranged around the central axis of the main body.

33. The battery cell according to claim 29, characterized in that The distance from the edge of the limiting and pressing portion to the central axis of the main body portion is less than or equal to the distance from the edge of the battery cell to the central axis of the battery cell.

34. The battery cell according to claim 29, characterized in that The main body is in a columnar structure, and the cross-sectional shape of the main body is circular, polygonal or racetrack-shaped.

35. The battery cell according to claim 29, characterized in that The main body is in a cylindrical structure, and the cross-sectional shape of the main body is circular, polygonal or racetrack-shaped.

36. The battery cell according to claim 29, characterized in that The main body and the limiting and pressing part are an integrated structure.

37. The battery cell according to claim 29, characterized in that The end edge of the main body is provided with a bendable folded edge outwardly.

38. The battery cell according to claim 37, characterized in that The position limiting and pressing portion is arranged on the folded edge; or the position limiting and pressing portion is located on one side of the folded edge.

39. A ring-shaped battery, characterized in that: A battery cell comprising any one of claims 1-38.

40. The annular battery according to claim 39, characterized in that The outer shell wall and the inner shell wall are arranged to form a cavity for accommodating the bare battery core, and the cross-sectional shape of the cavity is annular.

41. A battery, characterized in that: Comprising the annular battery as claimed in claim 39 or 40.

42. A battery module, characterized in that: The method comprises a plurality of annular batteries as claimed in claim 39 or 40, wherein the plurality of annular batteries are connected in series and / or in parallel; or a plurality of batteries as claimed in claim 41, wherein the plurality of batteries are connected in series and / or in parallel.

43. An electrical equipment, characterized in that: Comprising a plurality of annular batteries as claimed in claim 39 or 40; or, comprising a plurality of batteries as claimed in claim 41; or, comprising a battery module as claimed in claim 42.

44. A method for preparing a battery cell according to any one of claims 1 to 38, characterized in that: The following steps are involved: A welding gap is formed between the battery end cover and the battery housing in the axial direction of the inner shell wall, and the first electrical connector is circumferentially welded to the electrical connection portion of the battery end cover through the welding gap; After the first electrical connector is circumferentially welded to the electrical connection portion of the battery end cover, the battery end cover is welded to the end of the battery housing.

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