Battery unit and preparation method therefor, annular battery, battery, battery module, and electric device

Abstract

A battery unit and a preparation method therefor, an annular battery, a battery, a battery module, and an electric device, wherein the battery unit comprises: a battery case (1), wherein the battery case comprises an outer case wall (11) and an inner case wall (12) arranged in the outer case wall, part of a tube wall of the inner case wall protrudes inwards to form a protruding portion (121), and an electrical connection space (122) is formed on an outward side of the protruding portion; a bare cell (3) sleeved between the outer case wall and the inner case wall; and a first busbar (4) arranged at the bottom of the outer case wall, wherein the first busbar comprises an electrode connection portion (41) and a first tab connection portion (42), the first tab connection portion (42) is used for being electrically connected to a tab on one end of the bare cell (3), at least part of the electrode connection portion (41) is located in the electrical connection space (122), and the at least part of the electrode connection portion located in the electrical connection space (122) is electrically connected to the bottom of the outer case wall. The described solution can at least improve the reliability of electrical connection between one pole of the bare cell and the battery case.

Description

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

[0001] This application is based on Chinese patent applications with application number 202311183221.2 and application date September 13, 2023 and application number 202322491537.X and application date September 13, 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, a battery module and an electrical device. Background Art

[0003] Lithium-ion batteries have the advantages of light weight, high energy density, long cycle life and high safety performance, and have become the mainstream battery.

[0004] The main forms of lithium-ion batteries are prismatic, cylindrical, and pouch cells. Cylindrical batteries offer a high degree of automation, high production efficiency, good consistency, and relatively low cost.

[0005] Currently, lithium-ion batteries are used in many industries, and the working conditions in which lithium-ion batteries are used are becoming increasingly complex. For example, in certain working conditions, lithium-ion batteries may be subjected to severe vibration or external impact, which may easily cause at least one pole of the bare cell in the lithium-ion battery to fail in the electrical connection with the battery casing.

[0006] Summary of the Invention

[0007] The present invention provides a battery cell and a preparation method thereof, a ring-shaped battery, a battery, a battery module and an electrical device, which are at least used to improve the reliability of the electrical connection between one pole of a bare battery cell and a battery casing.

[0008] In a first aspect, the present invention provides a battery comprising:

[0009] A battery housing, the battery housing comprising an outer shell wall and an inner shell wall disposed within the outer shell wall, wherein a portion of the inner shell wall protrudes inwardly to form a protrusion, and an electrical connection space is formed on an outward side of the protrusion;

[0010] A bare battery cell is sleeved between the outer shell wall and the inner shell wall;

[0011] A first busbar is arranged at the bottom of the outer shell wall, and the first busbar includes an electrode connecting portion and a first tab connecting portion. The first tab connecting portion is used to electrically connect the tab at one end of the bare battery cell. The electrode connecting portion is at least partially located in the electrical connection space, and at least part of the electrode connecting portion located in the electrical connection space is electrically connected to the bottom of the outer shell wall.

[0012] As an implementation manner, the electrode connecting portion is provided with an overload narrowing area.

[0013] As an implementable manner, the overload narrowing zone includes a narrowing hole provided in the electrode connecting portion, and / or a narrowing groove provided on an edge of the electrode connecting portion.

[0014] As an implementation method, an insulating gasket is provided between the bottom of the outer shell wall and the first busbar, and in an orthographic projection perpendicular to the axis of the inner shell wall, the first tab connection portion and the overload narrowing zone are both located within the insulating gasket.

[0015] As an implementation manner, an insulating layer is provided on the outer side of the first busbar, and the insulating layer extends at least from the top of the insulating gasket to the bottom of the bare cell and covers the outer side of the bottom of the bare cell.

[0016] As an implementation manner, in the orthographic projection, the outer edge of the insulating layer coincides with the outer edge of the insulating gasket, or is located inside the outer edge of the insulating gasket.

[0017] As an implementation manner, in the axial direction of the inner shell wall, the protrusion passes through both ends of the inner shell wall.

[0018] As an implementation manner, the electrode connecting portion is fixed to the bottom of the housing wall by welding, and, in an orthographic projection perpendicular to the axial direction, the welding position is located within the electrical connection space.

[0019] As an implementation method, two or more protrusions are provided in the circumferential direction of the inner shell wall, and the electrode connecting portion is provided in a one-to-one correspondence with each protrusion.

[0020] As an implementation manner, the two or more protrusions are evenly arranged in the circumferential direction.

[0021] As an implementable manner, as an implementable manner, in an orthographic projection perpendicular to the axis of the inner shell wall, the shape of the electrical connection space is a triangle, a quadrilateral, a polygon, an arc or a U-shape.

[0022] As an implementation manner, one end of the inner shell wall is closed and the other end is open; or, both ends of the inner shell wall are open.

[0023] As an implementation manner, the wall thickness of the protrusion is less than or equal to the wall thickness of the remaining parts of the inner shell wall.

[0024] 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.

[0025] As an implementable manner, the hole is a heat dissipation hole.

[0026] As an implementation manner, the cross section of the hole is a circle, a regular polygon, an ellipse or a non-equilateral polygon.

[0027] 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.

[0028] As an implementable manner, the cross section of the bare cell is a circle, a regular polygon, an ellipse or a non-equilateral polygon.

[0029] As an achievable method, the maximum straight-line distance between any two points on the cross section of the hole is 0.11-0.65 of the maximum straight-line distance between any two points on the cross section of the shell wall.

[0030] As an implementation method, a plurality of heat dissipation protrusions are provided on the hole wall of the hole.

[0031] As an implementable method, a second bus is provided at the end of the bare cell facing away from the first bus, and the second bus includes a second pole tab connection portion and a pole post connection portion; the second pole tab connection portion is electrically connected to the pole tab of the bare cell, and the pole post connection portion is electrically connected to the pole post of the battery unit.

[0032] As an implementable manner, it further includes an end cover, on which the pole is provided; and / or, the end cover is provided with a liquid injection hole and an explosion-proof valve.

[0033] In a second aspect, the present invention provides a ring-shaped battery comprising the above-mentioned battery unit.

[0034] 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.

[0035] In a third aspect, the present invention provides a battery, including the above-mentioned annular battery.

[0036] In a fourth aspect, the present invention provides a battery module comprising a plurality of the aforementioned annular batteries, wherein the plurality of the annular batteries are connected in series and / or in parallel; or comprising a plurality of the aforementioned batteries, wherein the plurality of the batteries are connected in series and / or in parallel.

[0037] In a fifth aspect, the present invention provides an electrical device comprising a plurality of the aforementioned annular batteries; or, comprising a plurality of the aforementioned batteries; or, comprising the aforementioned battery module.

[0038] In a sixth aspect, the present invention provides a method for preparing the above-mentioned battery cell, comprising the following steps:

[0039] placing a first busbar in a battery housing, with the electrode connection portion of the first busbar at least partially located in the electrical connection space;

[0040] The welding needle is controlled to extend from the electrical connection space to the bottom of the shell wall, with the end of the welding needle in the electrical connection space, the electrode connecting part is pressed against the bottom of the shell wall, and the electrode connecting part is welded to the bottom of the shell wall.

[0041] As an achievable manner, the welding includes laser welding, ultrasonic welding, resistance welding, electromagnetic welding, friction welding or resistance welding.

[0042] The above scheme, by at least partially arranging the electrode connecting part of the first busbar electrically connected to the bare battery cell in the electrical connection space, the welding needle of the welding equipment extends from the electrical connection space to the bottom of the shell wall, and the end of the welding needle is in the electrical connection space, pressing the electrode connecting part against the bottom of the shell wall to weld the electrode connecting part to the bottom of the shell wall, can improve the welding quality of the electrode connecting part and the bottom of the shell wall, and thus improve the reliability of the connection between the electrode connecting part and the bottom of the shell wall, avoid the problem of electrical connection failure caused by separation of the electrode connecting part and the bottom of the shell wall, and therefore at least improve the reliability of the electrical connection between one pole of the bare battery cell and the battery shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] 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:

[0044] FIG1 is a perspective view of a battery provided in an embodiment of the present invention;

[0045] FIG2 is a top view of FIG1 ;

[0046] FIG3 is a cross-sectional view of the AA portion of FIG2;

[0047] FIG4 is a cross-sectional view of the BB portion of FIG3 ;

[0048] FIG5 is a perspective view of a battery housing according to an embodiment of the present invention;

[0049] FIG6 is a perspective view of a battery housing according to another embodiment of the present invention;

[0050] FIG7 is a front view of a first busbar provided in an embodiment of the present invention;

[0051] FIG8 is a front view of a first busbar provided by another embodiment of the present invention;

[0052] FIG9 is a cross-sectional view corresponding to the portion BB in FIG2 provided by another embodiment of the present invention;

[0053] FIG10 is a cross-sectional view corresponding to the portion BB in FIG2 provided by another embodiment of the present invention;

[0054] FIG11 is a cross-sectional view corresponding to the portion BB in FIG2 provided by another embodiment of the present invention;

[0055] FIG12 is a schematic diagram of the assembly of the second busbar and the end cover provided in an embodiment of the present invention;

[0056] FIG13 is a flow chart of a method for preparing a battery provided in an embodiment of the present invention.

[0057] Explanation of the accompanying drawings: battery shell 1, outer shell wall 11, inner shell wall 12, protrusion 121, electrical connection space 122, hole 123, end cover 2, pole 21, injection hole 22, explosion-proof valve 23, bare battery cell 3, first bus bar 4, electrode connection part 41, first pole ear connection part 42, narrowing hole 43, narrowing groove 44, insulating gasket 5, insulating layer 6, second bus bar 7, second pole ear connection part 71, pole column connection part 72. DETAILED DESCRIPTION

[0058] 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 portions relevant to the invention are shown in the accompanying drawings.

[0059] 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.

[0060] 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.

[0061] As shown in FIG1 to FIG5 , the battery unit provided by the embodiment of the present invention includes:

[0062] A battery housing 1 includes an outer shell wall 11 and an inner shell wall 12 disposed within the outer shell wall 11. A portion of the inner shell wall 12 protrudes inward to form a protrusion 121. An electrical connection space 122 is formed on the outward side of the protrusion 121.

[0063] In the example shown in FIG5 , two protrusions 121 and electrical connection spaces 122 are provided; in the example shown in FIG6 , four protrusions 121 and electrical connection spaces 122 are provided; of course, in other examples, other numbers of protrusions 121 and electrical connection spaces 122 may also be provided.

[0064] Generally, the battery housing 1 can be made of metal, such as steel, aluminum, and aluminum alloy, etc. On the one hand, it can protect the bare battery cell 3 disposed therein, and on the other hand, it can also serve as one of the poles of the battery, such as the negative pole or the positive pole.

[0065] At least one end of the battery housing 1 is open, and an end cover 2 can be welded to the opening. The end cover 2 can be provided with a pole 21, a liquid injection hole 22, etc.

[0066] The outer shell wall 11 and the inner shell wall 12 can both be annular structures. The inner shell wall 12 has a centrally located hole 123 extending along the axis of the inner shell wall 12, which can serve as a heat dissipation hole. Referring to at least FIG3 , the outer shell wall 11 and the inner shell wall 12 can be a one-piece structure, such as by casting or stamping a single metal plate. Also referring to FIG9 , FIG10 , or FIG11 , the outer shell wall 11 and the inner shell wall 12 can be a two-piece structure. The two-piece structure referred to here means that the outer shell wall 11 and the inner shell wall 12 are two separate components. For example, the inner shell wall 12 and the outer shell wall 11 can be connected together by welding. When the bottom of the outer shell wall 11 has a bottom plate, the inner shell wall 12 can be directly welded to the bottom plate of the outer shell wall 11, and the bottom plate of the outer shell wall 11 is provided with a hole connected to the hole 123; if the outer shell wall 11 is only an annular wall, the inner shell wall 12 can be connected to the outer shell wall 11 with the help of an end cover, for example, one end of the inner shell wall 12 is welded to the end cover, and the end cover is welded to one end of the outer shell wall 11. At this time, one end of the end cover can be provided with a hole connected to the hole 123.

[0067] In this embodiment, specifically, the cross-section of the outer shell wall 11 can be a circle, a regular polygon, an ellipse, or a non-equilateral polygon. Correspondingly, the cross-section of the inner shell wall 12 can also be a circle, a regular polygon, an ellipse, or a non-equilateral polygon. The cross-section of the hole 123 can also be a circle, a regular polygon, an ellipse, or a non-equilateral polygon.

[0068] Part of the tube wall of the inner shell wall 12 bulges inward to form a bulge 121. By setting the bulge 121, on the one hand, the surface area of ​​the inner side of the inner shell wall 12 can be increased, which is beneficial to improving the heat dissipation capacity of the center of the inner shell wall 12 and is beneficial to heat dissipation in the middle of the battery. On the other hand, an electrical connection space 122 can be formed on its outward side. The electrical connection space 122 can be used to store a certain amount of electrolyte to increase the electrolyte retention without increasing the volume of the battery. In addition, when the bare battery cell 3 expands due to temperature increase, the inner side of the bare battery cell 3 squeezes the inner shell wall 12. Due to the existence of the electrical connection space 122, after the inner shell wall 12 is squeezed, it will deform and shrink in the radial direction to offset the radial inward deformation of the bare battery cell 3, so as to avoid the bare battery cell 3 being able to expand outward in the radial direction due to the rigid structure of the inner shell wall 12 and causing the battery shell 1 to deform outward. That is to say, the electrical connection space 122 can also serve as a storage space for the electrolyte and a buffer space for the bare battery cell 3 during thermal expansion.

[0069] It should be noted that a cavity is formed between the outer shell wall 11 and the inner shell wall 12 , the cross-section of the cavity is annular, and the cavity serves as at least an installation space for the bare battery cell 3 .

[0070] The bare cell 3 is nested between the outer shell wall 11 and the inner shell wall 12, that is, located in the above-mentioned installation space. The cross section of the bare cell 3 can be circular, regular polygonal, elliptical, or non-equilateral polygonal.

[0071] At least referring to Figure 7, the first busbar 4 is arranged at the bottom of the outer shell wall 11, and the first busbar 4 includes a first tab connection part 42 and an electrode connection part 41. The first tab connection part 42 is used to electrically connect the tab at one end of the bare battery cell 3, and the electrode connection part 41 is at least partially located in the electrical connection space 122, and at least part of the electrode connection part 41 located in the electrical connection space 122 is electrically connected to the bottom of the outer shell wall 11.

[0072] For example, the first tab connection portion 42 of the first bus 4 is welded and fixed to the tab at one end of the bare cell 3, and the electrode connection portion 41 is welded and fixed to the bottom of the outer shell wall 11 in the electrical connection space 122; that is, the tab at one end of the bare cell 3 is electrically connected to the bottom of the outer shell wall 11 through the first bus 4, and the outer shell wall 11 serves as one of the poles of the battery, such as the positive pole or the negative pole.

[0073] The above scheme, by at least partially arranging the electrode connecting part 41 of the first bus 4 electrically connected to the bare battery cell 3 in the electrical connection space 122, the welding needle of the welding equipment extends from the electrical connection space 122 to the bottom of the outer shell wall 11, and the end of the welding needle is in the electrical connection space 122, pressing the electrode connecting part 41 to the bottom of the outer shell wall 11 to weld the electrode connecting part 41 to the bottom of the outer shell wall 11, can improve the welding quality of the electrode connecting part 41 and the bottom of the outer shell wall 11, and thus improve the reliability of the connection between the electrode connecting part 41 and the bottom of the outer shell wall 11, avoid the separation of the electrode connecting part 41 and the bottom of the outer shell wall 11, and cause the problem of electrical connection failure. Therefore, at least the reliability of the electrical connection between one pole of the bare battery cell 3 and the battery shell 1 is improved.

[0074] As an implementation method, the electrode connecting portion 41 is provided with an overload narrowing area.

[0075] By setting an overload narrowing zone in the electrode connection part 41, during the charging and discharging process, if the current increases abnormally, the electrode connection part 41 will melt in the overload narrowing zone, causing the first pole ear connection part 42 of the first bus 4 and the electrode connection part 41 to be short-circuited, that is, one of the poles of the battery is in a short-circuit state, which can avoid the bare battery cell 3 from heating up too high due to excessive current and causing combustion, explosion, etc. Therefore, by setting an overload narrowing zone in the electrode connection part 41, the safety of the battery can be improved.

[0076] As an implementable manner, as shown in FIG7 , the overload narrowing area is a narrowing hole 43 provided in the electrode connecting portion 41 . The narrowing hole 43 can be a through hole or a blind hole, and a through hole is preferably used.

[0077] As another possible implementation, as shown in FIG8 , the overload narrowing area is a narrowing groove 44 provided at the edge of the electrode connecting portion 41 .

[0078] As an achievable method, at least as shown in Figure 3, an insulating gasket 5 is provided between the bottom of the outer shell wall 11 and the first busbar 4, and in the orthographic projection perpendicular to the axis of the inner shell wall 12, the first pole ear connection portion 42 and the overload narrowing zone are both located within the insulating gasket 5.

[0079] By providing an insulating gasket 5 between the first busbar 4 and the bottom of the outer shell wall 11, the battery shell 1 and the first busbar 4 can be in an open-circuit state after the electrode is connected to the overload narrowing area and melts due to an abnormal increase in current in the battery. At this time, one of the poles of the bare battery cell 3 connected to the first busbar 4 is also in an open-circuit state with the battery shell 1, avoiding further aggravation of the fault.

[0080] In addition to providing an insulating gasket 5 between the first busbar 4 and the bottom of the shell wall 11 so that the shell and the first busbar 4 are in an open-circuit state after the electrode connection is melted in the overload narrowing zone, an insulating layer 6 can also be provided on the first busbar 4 except for the electrical connection position, and an insulating block and other structures can be provided between the first busbar 4 and the bottom of the shell wall 11, which are not listed here one by one.

[0081] As an implementation method, an insulating layer 6 is provided on the outer side of the first busbar 4 , and the insulating layer 6 extends at least from the top of the insulating gasket 5 to the bottom of the bare cell 3 and covers the outer side of the bottom of the bare cell 3 .

[0082] With the above structure, the outer side of the first busbar 4 and the bottom of the bare cell 3 are covered by at least the insulating layer 6, so that the outer side of the first busbar 4 and the outer side of the bare cell 3 are insulated from the inner side of the outer shell wall 11. In the case where the electrode connection is melted in the overload narrowing zone, the fault will not be further aggravated due to the electrical connection between the outer side of the first busbar 4 and the outer side of the bare cell 3 and the inner side of the outer shell wall 11.

[0083] As an implementation manner, in the orthographic projection, the outer edge of the insulating layer 6 coincides with the outer edge of the insulating gasket 5 , or is located inside the outer edge of the insulating gasket 5 .

[0084] The outer edge of the insulating layer 6 coincides with the outer edge of the insulating gasket 5, or is located inside the outer edge of the insulating gasket 5, so that there is a certain distance between the outer side of the first bus 4 and the outer side of the bare battery cell 3 and the inner side of the outer shell wall 11, thereby avoiding the occurrence of conductive connection between the outer side of the first bus 4 and the outer side of the bare battery cell 3 and the inner side of the outer shell wall 11.

[0085] As an implementation method, in the axial direction of the inner shell wall 12 , the protrusion 121 passes through both ends of the inner shell wall 12 .

[0086] As an implementation method, two or more protrusions 121 are provided in the circumferential direction of the inner shell wall 12 , and the electrode connecting portion 41 is provided in a one-to-one correspondence with each protrusion 121 .

[0087] By providing multiple electrode connection portions 41, the size of a single electrode connection portion 41 can be reduced while still meeting the current transmission requirements between the first tab connection portion 42 and the housing wall 11. As the size of a single electrode connection portion 41 is reduced, the current required for its fusing is correspondingly reduced. Therefore, based on the specific circumstances of the battery, the size of a single electrode connection portion 41 can be designed so that it can be fusing at a current that exceeds a small percentage of the rated current of the single electrode connection portion 41, thereby improving safety performance. The rated current of a single electrode connection portion 41 can be considered to be the current value of the maximum rated current of the battery divided by the number of electrode connection portions 41. The proportion of the fusing current of a single electrode connection portion 41 that exceeds the rated current of the single electrode connection portion 41 can be determined based on actual circumstances, for example, but not limited to, it can exceed 5%, 8%, 10%, etc., of the rated current of the single electrode connection portion 41.

[0088] As an implementation method, the two or more protrusions 121 are evenly arranged in the circumferential direction.

[0089] As an implementable manner, in an orthographic projection perpendicular to the axis of the inner shell wall 12, the shape of the electrical connection space 122 is a triangle, a quadrilateral, a polygon, an arc, or a U. In this example, the shape of the electrical connection space 122 is a quadrilateral, specifically a rectangle.

[0090] As an implementation manner, one end of the inner shell wall 12 is closed and the other end is open; or, both ends of the inner shell wall 12 are open.

[0091] Among them, at least as shown in Figure 9, the above-mentioned inner shell wall 12 itself can be closed at one end and open at the other end to form a hole 123 in the form of a blind hole, and the hole 123 is used to dissipate heat to the middle part of the battery. At this time, the bottom plate or end cover of the outer shell wall 11 is provided with a hole connected to the open end of the heat dissipation 123, so that the hole 123 dissipates heat to the middle part of the battery; in other examples, at least as shown in Figure 10, the above-mentioned inner shell wall 12 itself can be open at both ends, and one end thereof can be closed by other external components. For example, one end thereof is closed by the battery end cover or the bottom plate of the outer shell wall 11 to form a blind hole, and the blind hole can be used as the hole 123 to dissipate heat to the middle part of the battery.

[0092] Of course, in other examples, at least as shown in FIG11 , both ends of the inner shell wall 12 are open to form a through hole, which can serve as the hole 123, and the bottom plate or end cover of the outer shell wall 11 is provided with a hole connected to the hole 123, so that the hole 123 dissipates heat to the middle of the battery.

[0093] As an implementable manner, the maximum straight-line distance between any two points on the cross section of the hole 123 is 0.11-0.65 of the maximum straight-line distance between any two points on the cross section of the shell wall 11 .

[0094] As an implementable manner, the maximum straight-line distance between any two points on the cross section of the hole 123 is 5 mm to 30 mm.

[0095] As an implementable manner, the maximum straight-line distance between any two points on the cross section of the hole 123 is 8 mm to 25 mm.

[0096] As an implementable manner, the maximum straight-line distance between any two points on the cross section of the hole 123 is 10 mm to 15 mm.

[0097] For example, but not limited to, the maximum straight-line distance between any two points on the cross section of the hole 123 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 123 can be determined according to actual needs, as long as it satisfies the requirement that the maximum straight-line distance between any two points on the cross section of the hole 123 is 0.11-0.65 of the maximum straight-line distance between any two points on the cross section of the outer shell wall 11 of the battery housing 1. In addition, generally, the longer the battery cell is, the larger the maximum straight-line distance between any two points on the cross section of the hole 123 can be. That is, the maximum straight-line distance between any two points on the cross section of the hole 123 is positively correlated with the length of the battery cell, so that the cooling medium can fully exchange heat within the hole 123, thereby removing heat from the center of the battery cell to the greatest extent possible, thereby improving the heat dissipation effect on the battery cell. The heat dissipation of the cooling medium in the hole 123 can be achieved by inputting the cooling medium through a liquid cooling pipe, and the cooling medium dissipates heat to the center of the battery cell, or by heat conduction such as a cooling column to achieve heat dissipation to the center of the battery cell.

[0098] As an implementable method, to improve the heat dissipation capability of the battery cell, a plurality of heat dissipation protrusions (not shown) are provided on the wall of hole 123. By providing a plurality of heat dissipation protrusions on the wall of hole 123, the surface area of ​​the wall of hole 123 is increased. As the surface area increases, the area in contact with the cooling medium also increases accordingly, and the area for heat exchange increases accordingly. The heat in the middle of the battery cell can be fully exchanged with the cooling medium flowing in hole 123, thereby removing the heat in the middle of the battery cell and reducing the temperature of the battery equipped with the battery cell during charging and discharging.

[0099] As an implementation, each of the heat dissipation protrusions is an annular protrusion disposed around the wall of hole 123. The heat dissipation protrusions are provided as an annular protrusion surrounding the wall of hole 123, which can evenly dissipate heat along the circumference of the wall. It is understood that the heat dissipation protrusions can also be dot-shaped, columnar, or other shaped protrusion structures, and are not limited to the annular protrusions described in the above implementation.

[0100] As an implementable manner, the wall thickness of the protrusion 121 is less than or equal to the wall thickness of the remaining parts of the inner shell wall 12 , and the protrusion 121 and the remaining parts of the inner shell wall 12 are an integral structure.

[0101] The wall thickness of the protrusion 121 is set to be less than or equal to the wall thickness of the rest of the inner shell wall 12. On the one hand, it is convenient for processing. On the other hand, the radial stiffness of the protrusion 121 can be made less than or equal to the rest of the inner shell wall 12, so that the inner shell wall 12 is deformed when the bare battery cell 3 is radially squeezed inward to offset the radial inward deformation of the bare battery cell 3.

[0102] As an implementable method, a second busbar 7 is provided at one end of the bare cell 3 facing away from the first busbar 7, as shown in Figure 12, the second busbar 7 includes a second pole tab connection portion 71 and a pole connection portion 72; the second pole tab connection portion 71 is electrically connected to the pole tab of the bare cell 3, and the pole connection portion 72 is electrically connected to the pole 21 of the battery.

[0103] For example, the second busbar 7 is respectively fixed to the tab at the other end of the bare cell 3 and the pole 21 connected to the cover plate 2 by welding.

[0104] As an implementable manner, the second tab connection portion 71 is an annular connection portion, and a pole connection portion 72 extends outward from the second tab connection portion 71 . The pole connection portion 72 may be an electrical connection piece electrically connected to the pole 21 .

[0105] When making the connection, the second pole ear connection part 71 can be welded to the pole ear at the other end of the bare battery cell 3 first, and then the pole connection part 72 can be welded to the back of the pole 21 on the cover plate 2. Then, the cover plate 2 can be flipped over and covered on the opening of the battery shell 1, and then the end cover 2 can be welded to the outer shell wall 11.

[0106] As an implementable manner, an explosion-proof valve 23 is further provided on the end cover 2 .

[0107] In a second aspect, the present invention provides a ring-shaped battery, which includes the above-mentioned battery cells, and the cross-sectional shapes of the outer shell wall 11 and the inner shell wall 12 of the battery cells included in the ring-shaped battery are both ring-shaped, that is, the cross-sectional shape of the cavity formed by the outer shell wall 11 and the inner shell wall 12 is ring-shaped, thereby making the ring-shaped battery with the battery cells an annular battery as a whole.

[0108] In a third aspect, the present invention provides a battery comprising the aforementioned annular battery, so as to achieve better heat dissipation of the middle portion of the battery through the hole 123 .

[0109] 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.

[0110] The number of ring batteries used and their series-parallel relationship can be determined based on the output voltage and capacity of the battery module.

[0111] Alternatively, the battery module includes a plurality of the above-mentioned batteries, which are connected in series and / or in parallel. The number of batteries to be used and the series and parallel connection relationship thereof can be determined based on the output voltage and capacity of the battery module.

[0112] In a fifth aspect, the present invention provides an electrical device comprising the aforementioned annular battery; or, comprising the aforementioned battery; or, comprising the aforementioned battery module.

[0113] Electrical equipment includes, but is not limited to, new energy vehicles (electric vehicles, hybrid vehicles, etc.), digital products, etc.

[0114] In a sixth aspect, as shown in FIG13 , the present invention provides a method for preparing the above-mentioned battery, comprising the following steps:

[0115] S1: placing the first busbar 4 in the battery housing, with the electrode connecting portion 41 of the first busbar 4 at least partially located in the electrical connection space 122;

[0116] S2: Control the welding needle to extend from the electrical connection space 122 to the bottom of the shell wall 11, and the end of the welding needle is in the electrical connection space 122, press the electrode connecting part 41 to the bottom of the shell wall 11, and weld the electrode connecting part 41 to the bottom of the shell wall 11.

[0117] As an achievable manner, the welding includes laser welding, ultrasonic welding, resistance welding, electromagnetic welding, friction welding, and electric resistance welding.

[0118] It should be noted that in the solution using laser welding, a hole is provided at the end of the welding needle, and a laser generator is provided in the hole to generate laser light for welding.

[0119] 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.

[0120] 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 (1), the battery housing (1) comprising an outer shell wall (11) and an inner shell wall (12) arranged inside the outer shell wall (11), a portion of the tube wall of the inner shell wall (12) protrudes inward to form a protruding portion (121), and an electrical connection space (122) is formed on the outward side of the protruding portion (121); A bare battery core (3) is sleeved between the outer shell wall (11) and the inner shell wall (12); A first busbar (4) is arranged at the bottom of the outer shell wall (11), the first busbar (4) comprises an electrode connecting portion (41) and a first pole lug connecting portion (42), the first pole lug connecting portion (42) being used to electrically connect to the pole lug at one end of the bare battery cell (3), the electrode connecting portion (41) being at least partially located in the electrical connection space (122), and at least a portion of the electrode connecting portion (41) located in the electrical connection space (122) being electrically connected to the bottom of the outer shell wall (11).

2. The battery cell according to claim 1, characterized in that: The electrode connecting portion (41) is provided with an overload narrowing area.

3. The battery cell according to claim 2, characterized in that: The overload narrowing zone comprises a narrowing hole (43) arranged in the electrode connecting portion (41), and / or a narrowing groove (44) arranged at the edge of the electrode connecting portion (41).

4. The battery cell according to claim 2 or 3, characterized in that: An insulating gasket (5) is provided between the bottom of the outer shell wall (11) and the first busbar (4), and in an orthographic projection perpendicular to the axis of the inner shell wall (12), the first pole lug connection portion (42) and the overload narrowing zone are both located within the insulating gasket (5).

5. The battery cell according to claim 4, characterized in that: An insulating layer (6) is provided on the outer side of the first busbar (4), and the insulating layer (6) extends at least from the top of the insulating gasket (5) to the bottom of the bare battery cell (3), and covers the outer side of the bottom of the bare battery cell (3).

6. The battery cell according to claim 5, characterized in that: In the orthographic projection, the outer edge of the insulating layer (6) coincides with the outer edge of the insulating gasket (5), or is located within the outer edge of the insulating gasket (5).

7. The battery cell according to claim 1, characterized in that: In the axial direction of the inner shell wall (12), the protrusion (121) passes through both ends of the inner shell wall (12).

8. The battery cell according to claim 7, characterized in that: The electrode connecting portion (41) is fixed to the bottom of the housing wall (11) by welding, and, in an orthographic projection perpendicular to the axial direction, the welding position is located within the electrical connection space (122).

9. The battery cell according to claim 2 or 3, characterized in that: In the circumferential direction of the inner shell wall (12), two or more protrusions (121) are provided, and each protrusion (121) is provided with the electrode connecting portion (41) in a one-to-one correspondence.

10. The battery cell according to claim 9, characterized in that: The two or more protrusions (121) are evenly arranged in the circumferential direction.

11. The battery cell according to any one of claims 1 to 3, characterized in that: In an orthographic projection perpendicular to the axis of the inner shell wall (12), the shape of the electrical connection space (122) is a triangle, a quadrilateral, a polygon, an arc or a U shape.

12. The battery cell according to any one of claims 1 to 3, characterized in that: One end of the inner shell wall (12) is closed and the other end is open; or both ends of the inner shell wall (12) are open.

13. The battery cell according to any one of claims 1 to 3, characterized in that: The wall thickness of the protruding portion (121) is less than or equal to the wall thickness of the remaining parts of the inner shell wall (12).

14. The battery cell according to claim 1, characterized in that The inner shell wall (12) is provided with a hole (123), and the hole (123) extends along the axis of the inner shell wall (12).

15. The battery cell according to claim 14, characterized in that: The hole (123) is a heat dissipation hole.

16. The battery cell according to claim 15, characterized in that The cross section of the hole (123) is circular, regular polygonal, elliptical or non-equilateral polygonal.

17. The battery cell according to claim 1 or 15, characterized in that: The cross section of the outer shell wall (11) and / or the inner shell wall (12) is circular, regular polygonal, elliptical or non-equilateral polygonal.

18. The battery cell according to claim 1 or 15, characterized in that: The cross section of the bare battery core (5) is circular, regular polygonal, elliptical or non-equilateral polygonal.

19. The battery cell according to claim 14, characterized in that: The maximum value of the straight-line distance between any two points on the cross section of the hole (123) 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 (11).

20. The battery cell according to claim 14, characterized in that A plurality of heat dissipation protrusions are arranged on the hole wall of the hole (123).

21. The battery cell according to claim 14, characterized in that A second busbar (7) is provided at one end of the bare cell (3) facing away from the first busbar (4), and the second busbar (7) comprises a second pole lug connection portion and a pole column connection portion; the second pole lug connection portion is electrically connected to the pole lug of the bare cell (3), and the pole column connection portion is electrically connected to the pole column (21) of the battery unit.

22. The battery cell according to claim 21, characterized in that It also comprises an end cover (2), on which the pole (21) is provided; and / or, on which a liquid injection hole (22) and an explosion-proof valve (23) are provided.

23. A ring-shaped battery, characterized in that: A battery cell comprising any one of claims 1-22.

24. The annular battery according to claim 23, characterized in that The outer shell wall (1) and the inner shell wall (12) are arranged to form a cavity for accommodating the bare battery core (3), and the cross-sectional shape of the cavity is annular.

25. A battery, characterized in that: Comprising the annular battery as claimed in claim 23 or 24.

26. A battery module, characterized in that: The method comprises a plurality of annular batteries as claimed in claim 23 or 24, wherein the plurality of annular batteries are connected in series and / or in parallel; or the method comprises a plurality of batteries as claimed in claim 25, wherein the plurality of batteries are connected in series and / or in parallel.

27. An electrical equipment, characterized in that: Comprising a plurality of annular batteries as claimed in claim 23 or 24; or, comprising a plurality of batteries as claimed in claim 25; or, comprising a battery module as claimed in claim 26.

28. A method for preparing a battery cell according to any one of claims 1 to 22, characterized in that: The following steps are involved: Placing a first busbar (4) in a battery housing, and ensuring that the electrode connection portion (41) of the first busbar (4) is at least partially located in the electrical connection space (122); The welding needle is controlled to extend from the electrical connection space (122) to the bottom of the outer shell wall (11), and the end of the welding needle is in the electrical connection space (122), the electrode connecting part (41) is pressed against the bottom of the outer shell wall (11), and the electrode connecting part (41) and the bottom of the outer shell wall (11) are welded.

29. The preparation method according to claim 28, characterized in that: The welding includes laser welding, ultrasonic welding, resistance welding, electromagnetic welding, friction welding or resistance welding.

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