Battery cell and method of manufacturing the same, ring-shaped battery, battery, battery module, and electric device

Abstract

The application belongs to the technical field of lithium batteries, and discloses a battery unit, a preparation method of the battery unit, a ring-shaped battery, a battery, a battery module and a power utilization device, wherein the battery unit comprises a battery shell, the battery shell comprises a shell wall and an inner shell wall arranged in the shell wall, a part of the pipe wall of the inner shell wall is inwardly protruded to form a protruding part, and an electric connection space is formed on the outward side of the protruding part; a bare battery cell is sleeved between the shell wall and the inner shell wall; a first bus bar is arranged at the bottom of the shell wall, the first bus bar comprises an electrode connecting part and a first tab connecting part, the first tab connecting part is used for electrically connecting a tab at one end of the bare battery cell, the electrode connecting part is at least partially located in the electric connection space, and at least part of the electrode connecting part located in the electric connection space is electrically connected to the bottom of the shell wall. The above scheme can at least improve the reliability of the electrical connection between one pole of the bare battery cell and the battery shell.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery technology, specifically relating to a battery cell and its preparation method, a toroidal battery, a battery, a battery module, and an electrical device. Background Technology

[0002] Lithium-ion batteries have advantages such as light weight, high energy density, long cycle life, and high safety performance, and have become the mainstream battery type.

[0003] The main forms of lithium-ion batteries are prismatic batteries, cylindrical batteries, and pouch batteries. Cylindrical batteries have a high degree of automation in processing, high production efficiency, good consistency, and relatively low cost.

[0004] Currently, many industries have adopted lithium-ion batteries, and the working environments in which lithium-ion batteries are used are becoming increasingly complex. For example, in some working environments, lithium-ion batteries may be subjected to severe vibration or external impact, which may easily cause at least one electrode of the bare cell inside the lithium-ion battery to fail to connect with the battery casing. Summary of the Invention

[0005] This invention provides a battery cell and its preparation method, a toroidal battery, a battery, a battery module, and an electrical device, which are used to improve the reliability of the electrical connection between one electrode of the bare battery cell and the battery casing.

[0006] In a first aspect, the present invention provides a battery comprising:

[0007] A 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 inward to form a protrusion, and an electrical connection space is formed on the outward side of the protrusion.

[0008] A bare battery cell is fitted between the outer shell wall and the inner shell wall;

[0009] A first busbar is disposed at the bottom of the outer casing wall. The first busbar includes an electrode connection portion and a first tab connection portion. The first tab connection portion is used to electrically connect the tab at one end of the bare battery cell. The electrode connection portion is at least partially located within the electrical connection space, and at least a portion of the electrode connection portion located within the electrical connection space is electrically connected to the bottom of the outer casing wall.

[0010] As an implementation method, the electrode connection portion is provided with an overload reduction zone.

[0011] As an implementation method, the overload reduction area includes a reduction hole disposed in the electrode connection portion, and / or a reduction groove disposed on the edge of the electrode connection portion.

[0012] As an implementation, an insulating gasket is provided between the bottom of the outer shell wall and the first busbar, and in the orthographic projection perpendicular to the axis of the inner shell wall, both the first electrode connection and the overload reduction area are located within the insulating gasket.

[0013] As an implementation, an insulating layer is provided on the outer side of the first busbar, the insulating layer extending at least from the top of the insulating pad to the bottom of the bare cell, and covering the outer side of the bottom of the bare cell.

[0014] As an implementation, in the orthographic projection, the outer edge of the insulating layer coincides with or is located within the outer edge of the insulating pad.

[0015] As one possible implementation, the protrusion extends through both ends of the inner shell wall in the axial direction.

[0016] As an implementation method, the electrode connection portion is welded and fixed to the bottom of the outer casing wall, and in the orthographic projection perpendicular to the axis, the welding position is located within the electrical connection space.

[0017] As an implementation method, two or more protrusions are provided in the circumferential direction of the inner shell wall, and each protrusion is provided with an electrode connection portion corresponding to it.

[0018] As an implementation method, two or more of the protrusions are evenly arranged in the circumferential direction.

[0019] As an implementation method, in the orthographic projection perpendicular to the axis of the inner shell wall, the shape of the electrical connection space is a triangle, quadrilateral, polygon, arc, or U-shape.

[0020] As an alternative, 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.

[0021] As an alternative implementation, the wall thickness of the protrusion is less than or equal to the wall thickness of the rest of the inner shell wall.

[0022] As one possible implementation, the inner shell wall is provided with a hole that extends along the axis of the inner shell wall.

[0023] As an alternative implementation, the hole is a heat dissipation hole.

[0024] As an implementation method, the cross-section of the hole is circular, regular polygonal, elliptical, or non-equilateral polygonal.

[0025] As a possible implementation, the cross-section of the outer shell wall and / or the inner shell wall is circular, regular polygonal, elliptical, or non-equilateral polygonal.

[0026] As an implementation method, the cross-section of the bare battery cell is circular, regular polygonal, elliptical, or non-equilateral polygonal.

[0027] As an implementation method, the maximum straight-line distance between any two points on the cross-section of the hole is 0.11-0.65 times the maximum straight-line distance between any two points on the cross-section of the outer shell wall.

[0028] As an implementation method, multiple heat dissipation protrusions are provided on the wall of the hole.

[0029] As an implementation method, a second busbar is provided at one end of the bare cell away from the first busbar. The second busbar includes a second tab connection portion and a terminal connection portion. The second tab connection portion is electrically connected to the tab of the bare cell, and the terminal connection portion is electrically connected to the terminal of the battery cell.

[0030] As an alternative implementation, an end cap is also included, on which the pole is provided; and / or, on which the end cap is provided an injection hole and an explosion-proof valve.

[0031] Secondly, the present invention provides a ring-shaped battery, comprising the battery cell described above.

[0032] As one possible implementation, the outer shell wall and the inner shell wall enclose a cavity to accommodate the bare battery cell, the cavity having an annular cross-sectional shape.

[0033] Thirdly, the present invention provides a battery comprising the aforementioned toroidal battery.

[0034] Fourthly, the present invention provides a battery module comprising a plurality of the above-described ring-shaped batteries, wherein the plurality of ring-shaped batteries are connected in series and / or in parallel; or, comprising a plurality of the above-described batteries, wherein the plurality of batteries are connected in series and / or in parallel.

[0035] Fifthly, the present invention provides an electrical device comprising a plurality of the above-described ring-shaped batteries; or, comprising a plurality of the above-described batteries; or, comprising the above-described battery module.

[0036] Sixthly, the present invention provides a method for preparing the above-mentioned battery cell, comprising the following steps:

[0037] The first busbar is placed inside the battery housing, and the electrode connection portion of the first busbar is at least partially located within the electrical connection space.

[0038] The welding needle is controlled to extend from the electrical connection space to the bottom of the outer casing wall, with the end of the welding needle inside the electrical connection space, pressing the electrode connection part against the bottom of the outer casing wall, and welding the electrode connection part to the bottom of the outer casing wall.

[0039] As a possible method, the welding includes laser welding, ultrasonic welding, resistance welding, electromagnetic welding, friction welding, or resistance welding.

[0040] The above solution, by at least partially placing the electrode connection portion of the first busbar electrically connected to the bare cell within the electrical connection space, and by extending the welding needle of the welding equipment from the electrical connection space to the bottom of the outer casing wall with the end of the welding needle within the electrical connection space, presses the electrode connection portion against the bottom of the outer casing wall to weld the electrode connection portion to the bottom of the outer casing wall, can improve the welding quality between the electrode connection portion and the bottom of the outer casing wall, thereby improving the reliability of the connection between the electrode connection portion and the bottom of the outer casing wall, and avoiding the problem of separation between the electrode connection portion and the bottom of the outer casing wall, which would lead to electrical connection failure. Therefore, it at least improves the reliability of the electrical connection between one electrode of the bare cell and the battery casing. Attached Figure Description

[0041] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0042] Figure 1 A perspective view of a battery provided in an embodiment of the present invention;

[0043] Figure 2 for Figure 1 Top view;

[0044] Figure 3 for Figure 2 A sectional view of part AA;

[0045] Figure 4 for Figure 3 A cross-sectional view of the BB section;

[0046] Figure 5 A perspective view of the battery casing provided in an embodiment of the present invention;

[0047] Figure 6 A perspective view of a battery casing provided in another embodiment of the present invention;

[0048] Figure 7 A front view of the first bus provided in an embodiment of the present invention;

[0049] Figure 8 A front view of a first bus provided in another embodiment of the present invention;

[0050] Figure 9 Another embodiment of the present invention is provided corresponding to Figure 2 A sectional view of the BB section;

[0051] Figure 10Another embodiment of the present invention is provided corresponding to Figure 2 A sectional view of the BB section;

[0052] Figure 11 Another embodiment of the present invention is provided corresponding to Figure 2 A sectional view of the BB section;

[0053] Figure 12 This is an assembly diagram of the second busbar and end cap provided in an embodiment of the present invention;

[0054] Figure 13 A flowchart illustrating a battery preparation method provided in an embodiment of the present invention.

[0055] Explanation of reference numerals in the attached figures:

[0056] Battery casing 1, outer shell wall 11, inner shell wall 12, protrusion 121, electrical connection space 122, hole 123, end cap 2, electrode post 21, liquid injection hole 22, explosion-proof valve 23, bare cell 3, first busbar 4, electrode connection part 41, first electrode tab connection part 42, narrowing hole 43, narrowing groove 44, insulating gasket 5, insulating layer 6, second busbar 7, second electrode tab connection part 71, electrode post connection part 72. Detailed Implementation

[0057] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0058] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0059] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0060] like Figures 1-5 As shown, the battery cell provided in this embodiment of the invention includes:

[0061] Battery housing 1, the 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, and an electrical connection space 122 is formed on the outward side of the protrusion 121;

[0062] in, Figure 5 In the example shown, two protrusions 121 and an electrical connection space 122 are provided; Figure 6 In the example shown, four protrusions 121 and an electrical connection space 122 are provided; of course, in other examples, other numbers of protrusions 121 and electrical connection spaces 122 may be provided.

[0063] Generally, the battery casing 1 can be made of metal, such as steel, aluminum, or aluminum alloy. On the one hand, it can protect the bare battery cells 3 inside, and on the other hand, it can also serve as one of the terminals of the battery, such as the negative or positive terminal.

[0064] The battery casing 1 has an opening at at least one end, on which an end cap 2 can be welded. The end cap 2 can be provided with a terminal post 21, an injection hole 22, etc.

[0065] Both the outer shell wall 11 and the inner shell wall 12 can be annular structures. The inner shell wall 12 will have a central hole 123 extending along the axis of the inner shell wall 12, which can serve as a heat dissipation hole for heat dissipation. (See at least [reference needed]) Figure 3 As shown, the outer shell wall 11 and the inner shell wall 12 can be an integral structure, such as by casting or stamping a single metal sheet; see also Figure 9 , Figure 10 or Figure 11 As shown, the outer shell wall 11 and the inner shell wall 12 can also be a two-piece structure, meaning that the outer shell wall 11 and the inner shell wall 12 are two independent components. For example, the inner shell wall 12 can be connected to the outer shell wall 11 by welding. If 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 has a hole communicating with 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 by means of an end cap, such as welding one end of the inner shell wall 12 to the end cap, and welding the end cap to one end of the outer shell wall 11. In this case, one end of the end cap can have a hole communicating with the hole 123.

[0066] In this embodiment, specifically, the cross-section of the outer shell wall 11 can be circular, a regular polygon, an ellipse, or a non-equilateral polygon. Correspondingly, the cross-section of the inner shell wall 12 can also be circular, a regular polygon, an ellipse, or a non-equilateral polygon. The cross-section of the hole 123 can also be circular, a regular polygon, an ellipse, or a non-equilateral polygon.

[0067] A portion of the inner shell wall 12 protrudes inward to form a protrusion 121. By setting the protrusion 121, on the one hand, the surface area of ​​the inner side of the inner shell wall 12 can be increased, which is conducive to improving the heat dissipation capacity of the center of the inner shell wall 12 and facilitating 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, so as to increase the electrolyte holding without increasing the battery volume. In addition, when the bare cell 3 undergoes thermal expansion due to temperature rise, the inner side of the bare cell 3 compresses the inner shell wall 12. Due to the existence of the electrical connection space 122, the inner shell wall 12 will deform after being compressed, and will contract radially to offset the radial inward deformation of the bare cell 3. This avoids the bare cell 3 being able to only expand radially outward due to the rigid structure of the inner shell wall 12, which would cause the battery casing 1 to deform outward. In other words, the aforementioned electrical connection space 122 can also serve as a storage space for electrolyte and a buffer space for thermal expansion of the bare battery cell 3.

[0068] It should be noted that a cavity is formed between the outer shell wall 11 and the inner shell wall 12. The cross-sectional shape of the cavity is annular, and the cavity serves as at least the installation space for the bare battery cell 3.

[0069] The bare battery cell 3 is fitted between the outer shell wall 11 and the inner shell wall 12, that is, located within the aforementioned installation space. The cross-section of the bare battery cell 3 can be circular, regular polygonal, elliptical, or non-equilateral polygonal.

[0070] See also at least Figure 7 As shown, a first busbar 4 is disposed at the bottom of the outer casing wall 11. The first busbar 4 includes a first tab connection portion 42 and an electrode connection portion 41. The first tab connection portion 42 is used to electrically connect the tab at one end of the bare battery cell 3. The electrode connection portion 41 is at least partially located within the electrical connection space 122, and at least part of the electrode connection portion 41 located within the electrical connection space 122 is electrically connected to the bottom of the outer casing wall 11.

[0071] For example, the first tab connection part 42 of the first busbar 4 is welded and fixed to the tab at one end of the bare cell 3, and the electrode connection part 41 is welded and fixed to the bottom of the outer casing wall 11 within 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 casing wall 11 through the first busbar 4, and the outer casing wall 11 serves as one of the poles of the battery, such as the positive pole or the negative pole.

[0072] The above solution, by at least partially placing the electrode connection portion 41 of the first busbar 4 electrically connected to the bare cell 3 within the electrical connection space 122, and extending the welding needle of the welding equipment from the electrical connection space 122 to the bottom of the outer casing wall 11 with the end of the welding needle within the electrical connection space 122, presses the electrode connection portion 41 against the bottom of the outer casing wall 11 to weld the electrode connection portion 41 to the bottom of the outer casing wall 11, can improve the welding quality between the electrode connection portion 41 and the bottom of the outer casing wall 11, thereby improving the reliability of the connection between the electrode connection portion 41 and the bottom of the outer casing wall 11, and avoiding the problem of separation between the electrode connection portion 41 and the bottom of the outer casing wall 11, which would lead to electrical connection failure. Therefore, it at least improves the reliability of the electrical connection between one electrode of the bare cell 3 and the battery casing 1.

[0073] As an implementation method, the electrode connection portion 41 is provided with an overload narrowing region.

[0074] By setting an overload reduction zone in the electrode connection portion 41, if the current increases abnormally during charging and discharging, the electrode connection portion 41 will melt in the overload reduction zone, causing the first tab connection portion 42 of the first busbar 4 and the electrode connection portion 41 to be disconnected. That is, one of the electrodes of the battery is in an open circuit state, which can avoid the occurrence of combustion, explosion and other situations caused by excessive heat of the bare cell 3 due to excessive current. Therefore, by setting an overload reduction zone in the electrode connection portion 41, the safety of the battery can be improved.

[0075] As a possible approach, such as Figure 7 As shown, the overload reduction area is a reduction hole 43 provided in the electrode connection part 41. The reduction hole 43 can be a through hole or a blind hole, and a through hole is preferred.

[0076] As another possible approach, such as Figure 8 As shown, the overload reduction area is a reduction groove 44 provided on the edge of the electrode connection part 41.

[0077] As an implementable method, at least see [reference needed]. Figure 3 As shown, 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 electrode connection part 42 and the overload narrowing area are both located within the insulating gasket 5.

[0078] By providing an insulating pad 5 between the first busbar 4 and the bottom of the outer casing wall 11, the battery casing 1 and the first busbar 4 can be in an open circuit state after the electrode is connected to the overload reduction area and melts due to an abnormal increase in battery current. At this time, one of the electrodes of the bare cell 3 connected to the first busbar 4 is also in an open circuit state with the battery casing 1, thus preventing the fault from worsening.

[0079] In addition to using an insulating pad 5 between the first busbar 4 and the bottom of the outer casing wall 11 to ensure that the casing and the first busbar 4 are in an open circuit state after the electrode connection is melted in the overload reduction zone, an insulating layer 6 can also be provided on the first busbar 4 except at the electrical connection position, and an insulating block can be provided between the first busbar 4 and the bottom of the outer casing wall 11, etc. These are not listed here.

[0080] As an implementation, an insulating layer 6 is provided on the outer side of the first busbar 4, the insulating layer 6 extending at least from the top of the insulating pad 5 to the bottom of the bare cell 3, and covering the outer side of the bottom of the bare cell 3.

[0081] With the above structure, at least the outer side of the first busbar 4 and the bottom of the bare cell 3 are covered by 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 casing wall 11. In the event that the electrode is connected to the overload reduction zone and melts, 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 casing wall 11.

[0082] As an implementation, in the orthographic projection, the outer edge of the insulating layer 6 coincides with the outer edge of the insulating pad 5, or is located within the outer edge of the insulating pad 5.

[0083] The outer edge of the insulating layer 6 coincides with the outer edge of the insulating pad 5, or is located inside the outer edge of the insulating pad 5, so that there is a certain distance 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 casing wall 11, thus avoiding the occurrence of conductive 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 casing wall 11.

[0084] As an alternative implementation, the protrusion 121 extends through both ends of the inner shell wall 12 in the axial direction.

[0085] As an implementation method, two or more protrusions 121 are provided in the circumferential direction of the inner shell wall 12, and each of the protrusions 121 is provided with an electrode connection portion 41 in a one-to-one correspondence.

[0086] 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 electrode tab connection portion 42 and the outer casing wall 11. The reduced size of a single electrode connection portion 41 correspondingly reduces the current required for fusing. Therefore, depending on the specific battery requirements, the size of a single electrode connection portion 41 can be designed to fuse with a current exceeding a small percentage of its rated current, thereby improving safety performance. The rated current of a single electrode connection portion 41 can be considered as the battery's maximum rated current divided by the number of electrode connection portions 41. The percentage by which the fusing current of a single electrode connection portion 41 exceeds its rated current can be determined based on actual conditions, for example, but not limited to, exceeding 5%, 8%, 10%, etc., the rated current of the single electrode connection portion 41.

[0087] As an implementation method, two or more of the protrusions 121 are evenly arranged in the circumferential direction.

[0088] As an implementation, in the orthographic projection perpendicular to the axis of the inner shell wall 12, the electrical connection space 122 can be triangular, quadrilateral, polygonal, arc-shaped, or U-shaped. In this example, the electrical connection space 122 is quadrilateral, specifically, rectangular.

[0089] Alternatively, one end of the inner shell wall 12 may be closed and the other end open; or both ends of the inner shell wall 12 may be open.

[0090] Among them, at least such Figure 9 As shown, the inner shell wall 12 itself can be closed at one end and open at the other to form a blind hole 123. This hole 123 is used to dissipate heat from the middle of the battery. In this case, the bottom plate or end cap of the outer shell wall 11 is provided with a hole communicating with the open end of the heat dissipation 123, so that the hole 123 dissipates heat from the middle of the battery; in other examples, at least as shown Figure 10 As shown, the inner shell wall 12 can be open at both ends, with one end closed by other external components. For example, one end can be closed by the battery end cap or the bottom plate of the outer shell wall 11 to form a blind hole. This blind hole can serve as a hole 123 to dissipate heat from the middle of the battery.

[0091] Of course, in other examples, see at least Figure 11 As shown, both ends of the inner shell wall 12 are open to form through holes, which can serve as holes 123. The bottom plate or end cap of the outer shell wall 11 is provided with holes that communicate with holes 123 so that holes 123 can dissipate heat to the middle of the battery.

[0092] As an implementation method, the maximum straight-line distance between any two points on the cross-section of hole 123 is 0.11-0.65 of the maximum straight-line distance between any two points on the cross-section of outer shell wall 11.

[0093] As an feasible approach, the maximum straight-line distance between any two points on the cross-section of hole 123 is 5mm-30mm.

[0094] As an feasible approach, the maximum straight-line distance between any two points on the cross-section of hole 123 is 8mm-25mm.

[0095] As an feasible approach, the maximum straight-line distance between any two points on the cross-section of hole 123 is 10mm-15mm.

[0096] For example, but not limited to, the maximum straight-line distance between any two points on the cross-section of hole 123 can be 5.15mm, 5.3mm, 6.25mm, 7mm, 8.66mm, 13mm, 15.35mm, 18.7mm, 19mm, 22.9mm, 24mm, 28.4mm, 29.46mm, etc. The maximum straight-line distance between any two points on the cross-section of hole 123 can be determined according to actual needs, as long as it satisfies the condition that the maximum straight-line distance between any two points on the cross-section of hole 123 is 0.11-0.65 times the maximum straight-line distance between any two points on the cross-section of the outer wall 11 of the battery casing 1. Furthermore, generally, the longer the battery cell, the larger the maximum straight-line distance between any two points on the cross-section of hole 123 can be, meaning the maximum straight-line distance between any two points on the cross-section of hole 123 is positively correlated with the length of the battery cell. This allows the cooling medium to perform sufficient heat exchange within hole 123, maximizing the removal of heat from the center of the battery cell and improving heat dissipation. The cooling medium dissipates heat within the hole 123 by means of a liquid cooling pipe through which the cooling medium dissipates heat to the center of the battery cell, or by means of heat conduction such as a cooling column.

[0097] As a possible implementation, to improve the heat dissipation capacity of the battery cell, multiple heat dissipation protrusions (not shown in the figure) are provided on the wall of the hole 123. By providing multiple heat dissipation protrusions on the wall of the hole 123, the surface area of ​​the hole 123 is increased. As the surface area increases, the area in contact with the cooling medium also increases accordingly, thereby increasing the area for heat exchange. The heat in the middle of the battery cell can be fully exchanged with the cooling medium flowing in the hole 123 to remove the heat from the middle of the battery cell and reduce the temperature of the battery equipped with the battery cell during charging and discharging.

[0098] As one possible implementation, each of the heat dissipation protrusions is an annular protrusion surrounding the wall of hole 123. The annular protrusions surrounding the wall of hole 123 allow for uniform heat dissipation in the circumferential direction of the hole wall. It is understood that the heat dissipation protrusions can also be dot-shaped, columnar, or other shaped protrusions, and are not limited to the annular protrusions described above.

[0099] As an implementation method, the wall thickness of the protrusion 121 is less than or equal to the wall thickness of the rest of the inner shell wall 12, and the protrusion 121 and the rest of the inner shell wall 12 are integral structures.

[0100] Setting the wall thickness of the protrusion 121 to be less than or equal to the wall thickness of the rest of the inner shell wall 12 facilitates processing. On the other hand, it allows the radial stiffness of the protrusion 121 to be less than or equal to the rest of the inner shell wall 12, which makes it easier for the inner shell wall 12 to deform when it is subjected to radial inward pressure from the bare battery cell 3, thus offsetting the radial inward deformation of the bare battery cell 3.

[0101] As one possible implementation, the bare cell 3 is provided with a second busbar 7 at the end opposite to the first busbar 7, such as... Figure 12 As shown, the second busbar 7 includes a second tab connection portion 71 and a terminal connection portion 72; the second tab connection portion 71 is electrically connected to the tab of the bare cell 3, and the terminal connection portion 72 is electrically connected to the terminal 21 of the battery.

[0102] For example, the second busbar 7 is welded and fixed to the tab at the other end of the bare cell 3 and the post 21 connected to the cover plate 2.

[0103] As an implementation method, the second electrode connecting part 71 is an annular connecting part, and the second electrode connecting part 71 extends outward to the electrode post connecting part 72, which can be an electrical connecting piece, and the electrical connecting piece is electrically connected to the electrode post 21.

[0104] When making the connection, the second tab connection part 71 can be welded to the tab at the other end of the bare 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 placed on the opening of the battery casing 1. After that, the end cover 2 can be welded to the outer casing wall 11.

[0105] As an alternative, the end cap 2 is also equipped with an explosion-proof valve 23.

[0106] Secondly, the present invention provides a ring battery, which includes the aforementioned battery cell, and the cross-sectional shape of the outer shell wall 11 and the inner shell wall 12 of the battery cell 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 battery with battery cell as a whole a ring-shaped battery.

[0107] Thirdly, the present invention provides a battery comprising the aforementioned annular battery, so as to achieve better heat dissipation of the middle part of the battery through the hole 123.

[0108] Fourthly, the present invention provides a battery module comprising a plurality of ring-shaped batteries as described above, wherein the plurality of ring-shaped batteries are connected in series and / or in parallel.

[0109] The number of toroidal batteries and their series-parallel connection can be determined based on the output voltage and capacity of the battery module.

[0110] Alternatively, the battery module may include multiple batteries as described above, connected in series and / or in parallel. The number of batteries used and their series-parallel connection relationship can be determined based on the output voltage and capacity of the battery module.

[0111] Fifthly, the present invention provides an electrical device comprising the above-described ring-shaped battery; or, comprising the above-described battery; or, comprising the above-described battery module.

[0112] Electrical equipment, including but not limited to new energy vehicles (electric vehicles, hybrid vehicles, etc.) and digital products.

[0113] Sixth aspect, such as Figure 13 As shown, the present invention provides a method for preparing the above-mentioned battery, comprising the following steps:

[0114] S1: Place the first busbar 4 inside the battery housing, and ensure that the electrode connection portion 41 of the first busbar 4 is at least partially located within the electrical connection space 122;

[0115] S2: Control the welding needle to extend from the electrical connection space 122 into 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 connection part 41 against the bottom of the outer shell wall 11, and welding the electrode connection part 41 to the bottom of the outer shell wall 11.

[0116] As possible methods, the welding includes laser welding, ultrasonic welding, resistance welding, electromagnetic welding, friction welding, and resistance welding.

[0117] It should be noted that in the laser welding scheme, the end of the welding needle is provided with a hole, and a laser generator is installed in the hole. The laser generator produces a laser for welding.

[0118] It should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., used above to indicate orientation or positional relationships are based on the orientation 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, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, unless otherwise stated, "a plurality of" means two or more.

[0119] The above description is merely a preferred embodiment of this application and an explanation 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 technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A battery cell, characterized in that, include: The 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), and an electrical connection space (122) is formed on the outward side of the protrusion (121). The bare battery cell (3) is fitted between the outer shell wall (11) and the inner shell wall (12); The first busbar (4) is disposed at the bottom of the outer casing wall (11). The first busbar (4) includes an electrode connection part (41) and a first tab connection part (42). The first tab connection part (42) is used to electrically connect the tab at one end of the bare battery cell (3). 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 casing wall (11). The welding needle extends from the electrical connection space (122) into the bottom of the outer shell wall (11), and the end of the welding needle is inside the electrical connection space (122), pressing the electrode connection part (41) against the bottom of the outer shell wall (11), and welding the electrode connection part (41) to the bottom of the outer shell wall (11).

2. The battery cell according to claim 1, characterized in that, The electrode connection part (41) is provided with an overload narrowing zone.

3. The battery cell according to claim 2, characterized in that, The overload reduction area includes a reduction hole (43) disposed in the electrode connection portion (41) and / or a reduction groove (44) disposed on the edge of the electrode connection portion (41).

4. The battery cell according to claim 2 or 3, characterized in that, An insulating pad (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 electrode connection (42) and the overload reduction area are both located within the insulating pad (5).

5. The battery cell according to claim 4, characterized in that, An insulating layer (6) is provided on the outside of the first busbar (4). The insulating layer (6) extends at least from the top of the insulating pad (5) to the bottom of the bare cell (3) and covers the outside of the bottom of the bare 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 pad (5), or is located inside the outer edge of the insulating pad (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) extends through both ends of the inner shell wall (12).

8. The battery cell according to claim 2 or 3, characterized in that, Two or more protrusions (121) are provided in the circumferential direction of the inner shell wall (12), and each protrusion (121) is provided with an electrode connection part (41) corresponding to it.

9. The battery cell according to claim 8, characterized in that, Two or more of the protrusions (121) are evenly arranged in the circumferential direction.

10. The battery cell according to any one of claims 1-3, characterized in that, In the orthographic projection perpendicular to the axis of the inner shell wall (12), the electrical connection space (122) is polygonal, arc-shaped or U-shaped.

11. The battery cell according to any one of claims 1-3, 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.

12. The battery cell according to any one of claims 1-3, characterized in that, The wall thickness of the protrusion (121) is less than or equal to the wall thickness of the rest of the inner shell wall (12).

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

14. The battery cell according to claim 13, characterized in that, The hole (123) is a heat dissipation hole.

15. The battery cell according to claim 14, characterized in that, The cross-section of the hole (123) is circular, regular polygonal, elliptical, or non-equilateral polygonal.

16. The battery cell according to claim 1 or 14, 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.

17. The battery cell according to claim 1 or 14, characterized in that, The cross-section of the bare battery cell (3) is circular, regular polygonal, elliptical, or non-equilateral polygonal.

18. The battery cell according to claim 13, characterized in 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).

19. The battery cell according to claim 13, characterized in that, The hole (123) has multiple heat dissipation protrusions on its hole wall.

20. The battery cell according to claim 13, characterized in that, The bare cell (3) has a second busbar (7) at one end away from the first busbar (4). The second busbar (7) includes a second tab connection part and a terminal connection part. The second tab connection part is electrically connected to the tab of the bare cell (3), and the terminal connection part is electrically connected to the terminal (21) of the battery unit.

21. The battery cell according to claim 20, characterized in that, It also includes an end cap (2), on which the pole post (21) is provided; and / or, on which the end cap (2) is provided an injection hole (22) and an explosion-proof valve (23).

22. A toroidal battery, characterized in that, Includes the battery cell as described in any one of claims 1-21.

23. The toroidal battery according to claim 22, characterized in that, The outer shell wall (11) and the inner shell wall (12) enclose a cavity to accommodate the bare battery cell (3), and the cross-sectional shape of the cavity is annular.

24. A battery, characterized in that, Including the toroidal battery as described in claim 22 or 23.

25. A battery module, characterized in that, It includes multiple toroidal batteries as described in claim 22 or 23, wherein the multiple toroidal batteries are connected in series and / or in parallel; or, it includes multiple batteries as described in claim 24, wherein the multiple batteries are connected in series and / or in parallel.

26. An electrical appliance, characterized in that, It includes multiple toroidal batteries as described in claim 22 or 23; or, it includes multiple batteries as described in claim 24; or, it includes a battery module as described in claim 25.

27. A method for preparing a battery cell according to any one of claims 1-21, characterized in that, Includes the following steps: The first busbar (4) is placed inside the battery housing, and the electrode connection portion (41) of the first busbar (4) is at least partially located within the electrical connection space (122); The welding needle extends from the electrical connection space (122) into the bottom of the outer shell wall (11), and the end of the welding needle is inside the electrical connection space (122), pressing the electrode connection part (41) against the bottom of the outer shell wall (11), and welding the electrode connection part (41) to the bottom of the outer shell wall (11).

28. The preparation method according to claim 27, characterized in that, The welding includes laser welding, ultrasonic welding, electromagnetic welding, friction welding, or resistance welding.

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