Battery cell, ring battery, battery, battery module, electric device, and welding apparatus

Abstract

A battery cell, a ring battery, a battery, a battery module, an electric device, and a welding apparatus, relating to the technical field of lithium batteries. The battery cell comprises a battery shell, wherein the battery shell comprises an outer shell wall and an inner shell wall arranged in the outer shell wall; a bare cell, which is sleeved outside the inner shell wall, wherein a first gap is formed between an inner wall of the bare cell and an outer side wall of the inner shell wall; and a first busbar, which is arranged at the end of the bare cell located at the bottom of the outer shell wall, wherein the first busbar comprises a first electrical connection portion and a second electrical connection portion, the first electrical connection portion being electrically connected to a first tab of the bare cell, and at least part of the second electrical connection portion being located in the first gap and electrically connected to the bottom of the outer shell wall in the first gap. By means of the above solution, the reliability of electric connection between at least one electrode of the bare cell and the battery shell is improved.

Description

Battery cells, ring batteries, batteries, battery modules, electrical equipment and welding equipment

[0001] This application is based on the Chinese patent application with application number 202322493439.X and application date September 13, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0002] The utility model belongs to the technical field of lithium batteries, and specifically relates to a battery unit, a ring battery, a battery, a battery module, an electrical device and a welding 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] Utility Model Content

[0007] The utility model provides a battery unit, an annular battery, a battery, a battery module, an electrical device and a welding device, which are at least used to improve the reliability of the electrical connection between one pole of a bare battery core and a battery shell.

[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;

[0010] A bare battery cell is sleeved outside the inner shell wall, and a first gap is formed between the inner wall of the bare battery cell and the outer wall of the inner shell wall;

[0011] A first bus is arranged at one end of the bare battery cell located at the bottom of the outer shell wall, and the first bus includes a first electrical connection part and a second electrical connection part; the first electrical connection part is electrically connected to the first pole ear of the bare battery cell, and the second electrical connection part is at least partially located in the first gap and is electrically connected to the bottom of the outer shell wall in the first gap.

[0012] As an implementation method, the first electrical connection part includes a first annular connection part, the second electrical connection part includes a second annular connection part, the first annular connection part and the second annular connection part are coaxially arranged, and a second gap is provided between the outer edge of the second annular connection part and the inner edge of the first annular connection part, and at least one bridging part is provided in the second gap, and the bridging part is electrically connected to the first annular connection part and the second annular connection part respectively, and the bridging part is configured to disconnect the electrical connection between the first annular connection part and the second annular connection part when the fuse is blown.

[0013] As an implementation manner, a plurality of the bridging portions are evenly spaced apart in the second gap along the circumference of the inner shell wall.

[0014] As an implementation method, an insulating gasket is provided between the first busbar and the bottom of the housing wall;

[0015] In an orthographic projection perpendicular to the axis of the inner shell wall, the first electrical connection portion and the bridge portion are both located inside the insulating spacer.

[0016] As an implementation manner, the second electrical connection portion is fixed to the bottom of the housing wall by welding.

[0017] As an implementable manner, a protective sleeve is further included, which is passed through the outer side of the inner shell wall and is located in the first gap; and a third gap is provided between the inner side wall of the protective sleeve and the outer side wall of the inner shell wall.

[0018] As an implementation manner, a plurality of through holes are provided on the side wall of the protective cover.

[0019] As an implementation manner, the second electrical connection portion is at least partially located in the third gap, and is welded and fixed to the bottom of the housing wall in the third gap.

[0020] 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.

[0021] As an implementation manner, in an orthographic projection perpendicular to the axis of the inner shell wall, 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.

[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 method, the top of the shell wall is provided with an opening, the opening is sealed and fixed with a cover plate, and the cover plate is provided with a pole;

[0024] The other end of the bare cell is electrically connected to a second busbar, and the second busbar is electrically connected to the pole.

[0025] As an implementable manner, the second busbar includes a third annular connecting portion, an electrical connecting piece extending outward from the third annular connecting portion, and the electrical connecting piece is electrically connected to the pole.

[0026] 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.

[0027] As an implementable manner, the hole is a heat dissipation hole.

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

[0029] 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.

[0030] As an implementable manner, the cross section of the bare cell is a circle, a regular polygon, an ellipse or a non-equilateral polygon.

[0031] 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.

[0032] As an implementation method, a plurality of heat dissipation protrusions are provided on the hole wall of the hole.

[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 utility model provides a welding device for preparing the above-mentioned battery cell, or preparing the above-mentioned annular battery, or preparing the above-mentioned battery, the welding device includes a first welding head and a second welding head for moving toward each other, the first welding head includes an annular welding portion, the annular welding portion is used to extend into the first gap, and is used to press the second electrical connection portion and the bottom of the outer shell wall toward the second welding head, so that the second electrical connection portion is at least partially welded to the bottom of the outer shell wall.

[0039] As an implementation manner, a plurality of welding protrusions are provided on a side of the annular welding portion facing the second welding head, and the plurality of welding protrusions are evenly arranged along the circumference of the annular welding portion.

[0040] The above scheme, by locating the second electrical connection part of the first busbar electrically connected to the bare battery cell at least partially within the first gap, can weld the second electrical connection part to the bottom of the outer shell wall within the first gap through welding equipment to achieve reliable electrical connection between the second electrical connection part and the bottom of the outer shell wall within the first gap, avoiding the second electrical connection part from being separated from the bottom of the outer shell wall, which may cause electrical connection failure. Therefore, at least the reliability of the electrical connection between one pole of the bare battery cell and the battery shell is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] 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:

[0042] FIG1 is a perspective view of a battery provided in an embodiment of the present utility model;

[0043] FIG2 is an exploded view of FIG1 ;

[0044] FIG3 is a cross-sectional view of the AA portion of FIG1 ;

[0045] FIG4 is a schematic structural diagram of a first busbar provided by another embodiment of the present invention;

[0046] FIG5 is a cross-sectional view of a battery corresponding to an AA portion provided by another embodiment of the present invention;

[0047] FIG6 is a cross-sectional view of a battery corresponding to an AA portion provided by another embodiment of the present invention;

[0048] FIG7 is a cross-sectional view of a battery corresponding to an AA portion provided by another embodiment of the utility model;

[0049] FIG8 is a schematic diagram of a welding device in use according to another embodiment of the present invention.

[0050] Explanation of the accompanying drawings: outer shell wall 1, inner shell wall 2, hole 21, cover plate 3, pole 31, second bus bar 4, third annular connecting part 41, electrical connecting piece 42, protective cover 5, through hole 51, bare battery cell 6, pole ear 61, first bus bar 7, first annular connecting part 71, second annular connecting part 72, second gap 73, bridging part 74, center hole 75; insulating gasket 8, insulating layer 9, explosion-proof valve 10, liquid injection hole 20, first welding head 101, annular welding part 1011, welding protrusion 1012, second welding head 102, first gap K1, third gap K2. DETAILED DESCRIPTION

[0051] 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 utility model and are not intended to limit the utility model. It should also be noted that, for ease of description, only the portions relevant to the utility model are shown in the accompanying drawings.

[0052] 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.

[0053] 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.

[0054] At least as shown in FIG1 to FIG3 , the battery unit provided by the embodiment of the present invention includes:

[0055] A battery housing, comprising an outer shell wall 1 and an inner shell wall 2 disposed within the outer shell wall 1;

[0056] Generally, the battery housing can be made of metal, such as steel, aluminum, and aluminum alloy, etc. On the one hand, it can protect the bare battery core 6 arranged 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.

[0057] The outer shell wall 1 and the inner shell wall 2 can both be annular in structure. The inner shell wall 2 has a centrally located hole 21 extending along the axis of the inner shell wall 2, which can serve as a heat dissipation hole. As shown in at least FIG3 , the outer shell wall 1 and the inner shell wall 2 can be a single-piece structure, such as by casting or stamping a single metal plate. Also, as shown in FIG5 , FIG6 , or FIG7 , the outer shell wall 1 and the inner shell wall 2 can be a two-piece structure. The two-piece structure referred to here means that the outer shell wall 1 and the inner shell wall 2 are two separate components. For example, the inner shell wall 2 and the outer shell wall 1 can be connected by welding. In the case where the bottom of the outer shell wall 1 has a bottom plate, the inner shell wall 2 can be directly welded to the bottom plate of the outer shell wall 1, and the bottom plate of the outer shell wall 1 is provided with a hole connected to the hole 21; if the outer shell wall 1 is only an annular wall, the inner shell wall 2 can be connected to the outer shell wall 1 with the help of an end cover, for example, one end of the inner shell wall 2 is welded to the end cover, and the end cover is welded to one end of the outer shell wall 1, at this time, one end of the end cover can be provided with a hole connected to the hole 21.

[0058] In this embodiment, specifically, the cross-section of the outer shell wall 1 can be a circle, a regular polygon, an ellipse, or a non-equilateral polygon. Correspondingly, the cross-section of the inner shell wall 2 can also be a circle, a regular polygon, an ellipse, or a non-equilateral polygon. The cross-section of the hole 21 can also be a circle, a regular polygon, an ellipse, or a non-equilateral polygon.

[0059] It should be noted that a cavity is formed between the outer shell wall 1 and the inner shell wall 2 , the cross-section of the cavity is annular, and the cavity serves as at least an installation space for the bare battery cell 6 .

[0060] The bare battery core 6 is sleeved outside the inner shell wall 2, and a first gap K1 is formed between the inner wall of the bare battery core 6 and the outer wall of the inner shell wall 2;

[0061] The bare cell 6 referred to here may be a wound cell, which is composed of a positive electrode sheet, a separator and a negative electrode sheet stacked in sequence, and the three-layer structure is wound to form a bare cell 6 with a hole in the center.

[0062] The hole in the center of the bare battery cell 6 is sleeved outside the inner shell wall 2, and the size of the hole in the center of the bare battery cell 6 is larger than the size of the inner shell wall 2, so that a first gap K1 is formed between the inner wall of the bare battery cell 6 and the outer wall of the inner shell wall 2. The first gap K1 is at least used to provide a channel for external tools, such as but not limited to welding equipment, to extend into the bottom of the battery casing to electrically connect the first bus 7 to the bottom of the outer shell wall 1.

[0063] The cross section of the bare cell 6 can be a circle, a regular polygon, an ellipse or a non-equilateral polygon.

[0064] The first busbar 7 is arranged at one end of the bare battery cell 6 at the bottom of the outer shell wall 1, and the first busbar 7 includes a first electrical connection part and a second electrical connection part; the first electrical connection part is electrically connected to the first pole ear of the bare battery cell 6, and the second electrical connection part is at least partially located in the first gap K1, and is electrically connected to the bottom of the outer shell wall 1 in the first gap K1.

[0065] For example, the first electrical connection portion of the first busbar 7 can be welded to the first pole ear of the bare battery cell 6, and the second electrical connection portion of the first busbar 7 can be welded to the bottom of the outer shell wall 1 within the first gap K1, that is, the first pole ear of the bare battery cell 6 is electrically connected to the bottom of the outer shell wall 1 through the first busbar 7, and the outer shell wall 1 serves as one of the poles of the battery, such as the positive pole or the negative pole.

[0066] In the above scheme, by locating the second electrical connection portion of the first busbar 7 electrically connected to the bare battery cell 6 at least partially within the first gap K1, the second electrical connection portion can be welded to the bottom of the outer shell wall 1 within the first gap K1 by welding equipment, so as to achieve reliable electrical connection between the second electrical connection portion and the bottom of the outer shell wall 1 within the first gap K1, avoiding the second electrical connection portion from being separated from the bottom of the outer shell wall 1, which may cause the electrical connection to fail. Therefore, at least the reliability of the electrical connection between one pole of the bare battery cell 6 and the battery shell is improved.

[0067] In addition, in addition to allowing welding equipment to extend into the bottom of the battery casing to weld the second electrical connection portion to the bottom of the outer shell wall 1 within the first gap K1, the first gap K1 also allows, during the battery charging and discharging process, if the bare cell 6 undergoes thermal expansion, at least a portion of the expanded portion of the bare cell 6 can enter the first gap K1. In other words, at least a portion of the expansion of the bare cell 6 is offset by the first gap K1, reducing the outward extrusion force of the bare cell 6 on the battery casing, at least alleviating the problem of the battery casing expanding and deforming due to the expansion of the bare cell 6. In extreme cases, the entire expansion of the bare cell 6 is offset by the first gap K1. In this case, the bare cell 6 does not exert an outward extrusion force on the battery casing, that is, the battery casing will not deform due to the thermal expansion of the bare cell 6.

[0068] As an implementable manner, referring at least to FIG4 , the first electrical connection portion includes a first annular connection portion 71, and the second electrical connection portion includes a second annular connection portion 72. The first annular connection portion 71 and the second annular connection portion 72 are coaxially arranged, and a second gap 73 is provided between the outer edge of the second annular connection portion 72 and the inner edge of the first annular connection portion 71. At least one bridging portion 74 is provided in the second gap 73, and the bridging portion 74 is electrically connected to the first annular connection portion 71 and the second annular connection portion 72, respectively.

[0069] For example, but not limited to, the first bus 7 can be produced by stamping, such as stamping a metal sheet to remove a portion of the metal material on the metal sheet to form a first annular connection portion 71 and a second annular connection portion 72 located within the first annular connection portion 71, and a second gap 73 is provided between the outer edge of the second annular connection portion 72 and the inner edge of the first annular connection portion 71, and a bridging portion 74 is provided in the second gap 73, and the bridging portion 74 is electrically connected to the first annular connection portion 71 and the second annular connection portion 72, respectively. That is, a portion of the material on the metal sheet is punched out between the first annular connection portion 71 and the second annular connection portion 72 to form the second gap 73, and the remaining portion of the material on the metal sheet forms the bridging portion 74.

[0070] The second electrical connection portion includes a second annular connection portion 72. The second annular connection portion 72 can be sleeved on the outside of the inner shell wall 2 through its center hole 75 and is located at least within the first gap K1. This can increase the area of ​​electrical connection between the second electrical connection portion and the bottom of the outer shell wall 1. As the electrical connection area increases, on the one hand, the contact resistance can be reduced, avoiding abnormal heating at the connection due to excessive resistance, which leads to increased power loss. On the other hand, the connection strength between the second electrical connection portion and the bottom of the outer shell wall 1 can be improved, reducing the possibility of separation of the second electrical connection portion and the bottom of the outer shell wall 1.

[0071] In addition, since a bridge portion 74 is provided in the second gap 73 between the first annular connecting portion 71 and the second annular connecting portion 72, that is, only a partial area between the first annular connecting portion 71 and the second annular connecting portion 72 is connected (the area corresponding to the bridge portion 74), during the charging and discharging process, if the current increases abnormally, the bridge portion 74 will be melted, causing one pole of the battery to be in an open circuit state (that is, the electrical connection between the first annular connecting portion 71 and the second annular connecting portion 72 is disconnected), which can avoid the bare battery cell 6 from heating up too high due to excessive current, resulting in combustion, explosion, etc. Therefore, by providing a bridge portion 74 in the second gap 73 between the first annular connecting portion 71 and the second annular connecting portion 72, the safety of the battery can be improved.

[0072] As an implementation method, along the circumference of the inner shell wall 2, a plurality of bridge portions 74 are evenly spaced in the second gap 73. In this example, four bridge portions 74 are evenly spaced.

[0073] By evenly disposing multiple bridge portions 74 around the circumference of the inner shell wall 2, the size of a single bridge portion 74 can be reduced while still meeting the current transmission requirements between the first annular connecting portion 71 and the second annular connecting portion 72. The reduced size of a single bridge portion 74 also reduces the current required for its fusing. Therefore, based on the specific battery conditions, the size of a single bridge portion 74 can be designed to fuse at a current that exceeds a small percentage of the rated current of the single bridge portion 74, thereby improving safety performance. The rated current of a single bridge portion 74 can be considered to be the maximum rated current of the battery divided by the number of bridge portions 74. The percentage by which the fusing current of a single bridge portion 74 exceeds the rated current of the single bridge portion 74 can be determined based on actual conditions, and can, for example, but not limited to, exceed 5%, 8%, 10%, etc., of the rated current of the single bridge portion 74.

[0074] As an implementation method, referring to at least FIG3 , an insulating gasket 8 is provided between the first busbar 7 and the bottom of the housing wall 1 ;

[0075] In an orthographic projection perpendicular to the axis of the inner shell wall 2 , the first electrical connection portion and the bridge portion 74 are both located inside the insulating spacer 8 .

[0076] By providing an insulating gasket 8 between the first busbar 7 and the bottom of the outer shell wall 1, the battery shell and the first busbar 7 can be in an open-circuit state after the bridge portion 74 melts due to an abnormal increase in battery current. At this time, one of the poles of the bare battery cell 6 connected to the first busbar 7 is also in an open-circuit state with the battery shell, avoiding further aggravation of the fault.

[0077] In addition to providing an insulating gasket 8 between the first busbar 7 and the bottom of the shell wall 1 so that the shell and the first busbar 7 are in an open-circuit state after the bridge portion 74 is melted, an insulating layer can also be provided on the first busbar 7 except for the electrical connection position, and an insulating block and other structures can be provided between the first busbar 7 and the bottom of the shell wall 1, which are not listed here one by one.

[0078] As an implementation method, the second electrical connection portion is fixed to the bottom of the housing wall 1 by welding.

[0079] The welding referred to herein may be performed by laser welding, ultrasonic welding, resistance welding, electromagnetic welding, friction welding, electric resistance welding, and the like.

[0080] As an implementable manner, a protective cover 5 is further included, which is passed through the outer side of the inner shell wall 2 and is located in the first gap K1; and a third gap K2 is provided between the inner side wall of the protective cover 5 and the outer side wall of the inner shell wall 2.

[0081] The protective cover 5 may be a tubular structure, and its cross-sectional shape may be determined according to actual conditions, such as circular, elliptical, quadrilateral, or polygonal. As one preferred implementation, the cross-sectional shape of the protective cover 5 is generally the same as the cross-sectional shape of the inner shell wall 2. Of course, in some examples, the cross-sectional shape of the inner shell wall 2 may also be different.

[0082] The protective sleeve 5 is passed through the outer side of the inner shell wall 2 , and the protective sleeve 5 and the inner shell wall 2 are gap-fitted to form a third gap K2 between the protective sleeve 5 and the inner shell wall 2 .

[0083] The protective cover 5 is used to support and protect the inner side of the bare battery cell 6 .

[0084] Generally, the protective cover 5 is an insulating protective cover. For example, its material can be insulating paper, rubber, or plastic. Preferably, the protective cover 5 has a certain degree of flexibility, that is, the protective cover 5 is a flexible protective cover. This facilitates the protective cover 5 to deform toward the inner shell wall 2 as the bare battery cell 6 thermally expands. This avoids the protective cover 5 being a rigid structure, which prevents the bare battery cell 6 from thermally expanding toward the inner shell wall 2, causing the bare battery cell 6 to thermally expand toward the outer shell wall 1, resulting in outward deformation of the outer shell wall 1.

[0085] At least referring to Figures 2 and 3, in addition to buffering at least a portion of the thermal expansion and deformation of the bare battery cell 6, the third gap K2 can also accommodate a portion of the electrolyte. In order to allow the electrolyte to flow on both sides of the protective cover 5, a plurality of through holes 51 are provided on the side walls of the protective cover 5, so that the electrolyte in the third gap K2 can flow toward the bare battery cell 6 through the through holes 51, and can also flow from the bare battery cell 6 toward the third gap K2.

[0086] As an implementation manner, the second electrical connection portion is at least partially located in the third gap K2 and is welded and fixed to the bottom of the housing wall 1 in the third gap K2.

[0087] As one of the preferred implementation methods, the bare cell 6 and the protective cover 5 are interference fit. When the battery is assembled, the protective cover 5 can be first inserted into the hole in the center of the bare cell 6. Since the bare cell 6 and the protective cover 5 are interference fit, the two can be assembled into the battery shell together, which can improve the efficiency of assembly. Moreover, since there is a protective cover 5 in the hole in the center of the bare cell 6 when the bare cell 6 is loaded into the battery shell, the protective cover 5 can prevent the hole in the center of the bare cell 6 from colliding with the outer shell wall 1 during the assembly process, causing damage to the center of the bare cell 6 and causing problems such as short circuit. After the protective cover 5 is loaded into the battery shell along with the bare cell 6, a third gap K2 is formed between the protective cover 5 and the inner shell wall 2. The welding equipment extends into the bottom of the battery shell through the third gap K2 and welds at least part of the second electrical connection portion to the bottom of the outer shell wall 1.

[0088] As an achievable method, at least as shown in FIG3 , an insulating layer 9 is provided on the outside of the first busbar 7 , and the insulating layer 9 extends at least from the top of the insulating gasket 8 to the bottom of the bare cell 6 , and is wrapped around the outside of the bottom of the bare cell 6 .

[0089] By adopting the above structure, the outer side of the first busbar 7 and the bottom of the bare battery cell 6 are covered by at least the insulating layer 9, so that the outer side of the first busbar 7 and the outer side of the bare battery cell 6 are insulated from the inner side of the outer shell wall 1. When the bridge portion 74 is blown, the fault will not be further aggravated due to the electrical connection between the outer side of the first busbar 7 and the outer side of the bare battery cell 6 and the inner side of the outer shell wall 1.

[0090] As an implementation manner, in an orthographic projection perpendicular to the axis of the inner shell wall 2 , the outer edge of the insulating layer 9 coincides with the outer edge of the insulating gasket 8 , or is located inside the outer edge of the insulating gasket 8 .

[0091] The outer edge of the insulating layer 9 coincides with the outer edge of the insulating gasket 8, or is located inside the outer edge of the insulating gasket 8, so that there is a certain distance between the outer side of the first bus 7 and the outer side of the bare battery cell 6 and the inner side of the outer shell wall 1, thereby avoiding the occurrence of conductive connection between the outer side of the first bus 7 and the outer side of the bare battery cell 6 and the inner side of the outer shell wall 1.

[0092] As an implementation manner, one end of the inner shell wall 2 is closed and the other end is open; or, both ends of the inner shell wall 2 are open.

[0093] Among them, at least as shown in Figure 6, the above-mentioned inner shell wall 2 itself can be closed at one end and open at the other end to form a hole 21 in the form of a blind hole, which 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 1 is provided with a hole connected to the open end of the hole 21, so that the hole 21 dissipates heat to the middle part of the battery; in other examples, at least as shown in Figure 5, the above-mentioned inner shell wall 2 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 1 to form a blind hole, which can be used as the hole 21 to dissipate heat to the middle part of the battery.

[0094] Of course, in other examples, at least as shown in FIG7 , both ends of the inner shell wall 2 are open to form a through hole, which can serve as the hole 21, and the bottom plate or end cover of the outer shell wall 1 is provided with a hole connected to the hole 21, so that the hole 21 dissipates heat to the middle of the battery.

[0095] As an implementable manner, the maximum straight-line distance between any two points on the cross section of the hole 21 is 0.11-0.65 of the maximum straight-line distance between any two points on the cross section of the housing wall 1 .

[0096] As an implementable manner, the maximum straight-line distance between any two points on the cross section of the hole 21 is 5 mm to 30 mm.

[0097] As an implementable manner, the maximum straight-line distance between any two points on the cross section of the hole 21 is 8 mm to 25 mm.

[0098] As an implementable manner, the maximum straight-line distance between any two points on the cross section of the hole 21 is 10 mm to 15 mm.

[0099] For example, but not limited to, the maximum straight-line distance between any two points on the cross section of the hole 21 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 21 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 21 is 0.11-0.65 of the maximum straight-line distance between any two points on the cross section of the outer shell wall 1 of the battery shell. In addition, generally, the longer the length of the battery cell, the larger the maximum straight-line distance between any two points on the cross section of the hole 21 can be. That is, the maximum straight-line distance between any two points on the cross section of the hole 21 is positively correlated with the length of the battery cell, so that the cooling medium can fully exchange heat within the hole 21, 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 21 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 unit, or by heat conduction such as a cooling column to achieve heat dissipation to the center of the battery unit.

[0100] 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 21. By providing a plurality of heat dissipation protrusions on the wall of hole 21, the surface area of ​​the hole 21 wall 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 21, thereby removing the heat from the middle of the battery cell and reducing the temperature of the battery equipped with the battery cell during charging and discharging.

[0101] As an implementation, each of the heat dissipation protrusions is an annular protrusion disposed around the wall of hole 21. The heat dissipation protrusions are provided as an annular protrusion surrounding the wall of hole 21, 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 protrusions, and are not limited to the annular protrusions described in the above implementation.

[0102] As an implementation method, the top of the shell wall 1 is provided with an opening, the opening is sealed and fixed with a cover plate 3, and the cover plate 3 is provided with a pole 31; wherein, the cover plate 3 can be sealed and fixedly connected to the shell wall 1 by welding.

[0103] The end cap 3 may be provided with an explosion-proof valve 10, an injection hole 20, etc., through which electrolyte may be injected into the battery cell. During the formation process after the electrolyte is injected, the injection hole 20 may serve as a vent for discharging gases generated by the formation from the battery housing. After the formation is completed, the injection hole 20 may be sealed, for example, but not limited to, by welding a sealing nail into the injection hole 20.

[0104] The other end of the bare cell 6 is electrically connected to a second busbar 4 , and the second busbar 4 is electrically connected to the pole 31 .

[0105] For example, the second busbar 4 is respectively fixed to the tab 61 at the other end of the bare cell 6 and the pole 31 connected to the cover plate 3 by welding.

[0106] As an implementable manner, the second busbar 4 includes a third annular connecting portion 41 , and an electrical connecting piece 42 extends outward from the third annular connecting portion 41 . The electrical connecting piece 42 is electrically connected to the pole 31 .

[0107] When making the connection, the third annular connecting part 41 can be welded to the pole ear at the other end of the bare battery cell 6 first, and then the electrical connecting piece 42 can be welded to the back of the pole 31 on the cover plate. Then the cover plate 3 can be flipped over and covered on the opening of the battery shell, and then the end cover can be welded to the outer shell wall 1.

[0108] In a second aspect, the utility model provides an annular battery, which includes the above-mentioned battery cell, and the cross-sectional shape of the cavity formed between the outer shell wall 1 and the inner shell wall 2 of the battery cell included in the annular battery is annular, so that the annular battery with the battery cell is an annular battery as a whole.

[0109] In a third aspect, the present invention provides a battery, which includes the above-mentioned annular battery, so as to achieve better heat dissipation of the middle part of the battery through the hole 21.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] Electrical equipment includes, but is not limited to, new energy vehicles (electric vehicles, hybrid vehicles, etc.), digital products, etc.

[0115] In the sixth aspect, referring to at least Figure 8, the utility model provides a welding device for preparing the above-mentioned battery cell; or preparing the above-mentioned annular battery; or preparing the above-mentioned battery, the welding device includes a first welding head 101 and a second welding head 102 for moving toward each other, the first welding head 101 includes an annular welding portion 1011, and the annular welding portion 1011 is used to extend into the first gap K1, and is used to press the second electrical connection portion and the bottom of the outer shell wall 1 toward the second welding head 102, so that the second electrical connection portion is at least partially welded to the bottom of the outer shell wall 1.

[0116] The first welding head 101 and the second welding head 102 that move toward each other can have one of them move while the other is fixed, or both can move.

[0117] Take the example where one of them can move and the other is fixed. For example, the second welding head 102 is fixed, and the top is used to place the battery to be welded. The first welding head 101 can move in the vertical direction. When welding, the first welding head 101 moves downward, and the annular welding portion 1011 extends into the first gap K1 of the battery until the bottom of the outer shell wall 1 and the first bus 7 are added between the first welding head 101 and the second welding head 102. The bottom of the outer shell wall 1 and the first bus 7 are welded together through the first welding head 101 and the second welding head 102.

[0118] As an implementation method, a plurality of welding protrusions 1012 are provided on a side of the annular welding portion 1011 facing the second welding head 102 , and the plurality of welding protrusions 1012 are evenly arranged along the circumference of the annular welding portion 1011 .

[0119] By providing a plurality of welding protrusions 1012 on the annular welding portion 1011 , spot welding can be performed on the bottom of the housing wall 1 and the first bus bar 7 to improve welding quality.

[0120] It should also be noted that as long as the second welding head 102 can be powered and can provide support for the battery to be welded, its shape is not uniquely limited. For example, but not limited to, it can be cylindrical, plate-shaped, tubular, etc. In this example, a tubular structure is used.

[0121] 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.

[0122] 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 utility model disclosed 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 casing, the battery casing comprising an outer casing wall (1) and an inner casing wall (2) arranged inside the outer casing wall (1); A bare battery core (6) is sleeved outside the inner shell wall (2), and a first gap (K1) is formed between the inner wall of the bare battery core (6) and the outer wall of the inner shell wall (2); A first busbar (7) is arranged at one end of the bare battery cell (6) located at the bottom of the outer shell wall (1), and the first busbar (7) comprises a first electrical connection portion and a second electrical connection portion; the first electrical connection portion is electrically connected to the first pole ear of the bare battery cell (6), and the second electrical connection portion is at least partially located in the first gap (K1), and is electrically connected to the bottom of the outer shell wall (1) in the first gap (K1).

2. The battery cell according to claim 1, characterized in that: The first electrical connection part comprises a first annular connection part (71), and the second electrical connection part comprises a second annular connection part (72); the first annular connection part (71) and the second annular connection part (72) are coaxially arranged, and a second gap (73) is arranged between the outer edge of the second annular connection part (72) and the inner edge of the first annular connection part (71); at least one bridge part (74) is arranged in the second gap (73); the bridge part (74) is electrically connected to the first annular connection part (71) and the second annular connection part (72) respectively, and the bridge part (74) is configured to disconnect the electrical connection between the first annular connection part (71) and the second annular connection part (72) when the fuse is blown.

3. The battery cell according to claim 2, characterized in that: Along the circumferential direction of the inner shell wall (2), a plurality of bridging portions (74) are evenly spaced within the second gap (73).

4. The battery cell according to claim 2 or 3, characterized in that: An insulating gasket (8) is provided between the first busbar (7) and the bottom of the housing wall (1); In an orthographic projection perpendicular to the axis of the inner shell wall (2), the first electrical connection portion and the bridging portion (74) are both located inside the insulating gasket (8).

5. The battery cell according to claim 4, characterized in that: The second electrical connection portion is fixed to the bottom of the housing wall (1) by welding.

6. The battery cell according to any one of claims 1 to 3, characterized in that: It also comprises a protective sleeve (5), which is passed through the outer side of the inner shell wall (2) and is located in the first gap (K1); and a third gap (K2) is provided between the inner side wall of the protective sleeve (5) and the outer side wall of the inner shell wall (2).

7. The battery cell according to claim 6, characterized in that: A plurality of through holes (51) are provided on the side wall of the protective cover (5).

8. The battery cell according to claim 6, characterized in that: The second electrical connection portion is at least partially located in the third gap (K2) and is welded and fixed to the bottom of the housing wall (1) in the third gap (K2).

9. The battery cell according to claim 4, characterized in that: An insulating layer (9) is provided on the outer side of the first busbar (7), and the insulating layer (9) extends at least from the top of the insulating gasket (8) to the bottom of the bare battery cell (6), and covers the outer side of the bottom of the bare battery cell (6).

10. The battery cell according to claim 9, characterized in that: In an orthographic projection perpendicular to the axis of the inner shell wall (2), the outer edge of the insulating layer (9) coincides with the outer edge of the insulating gasket (8), or is located inside the outer edge of the insulating gasket (8).

11. The battery cell according to any one of claims 1 to 3, characterized in that: One end of the inner shell wall (2) is closed and the other end is open; or both ends of the inner shell wall (2) are open.

12. The battery cell according to any one of claims 1 to 3, characterized in that: An opening is provided at the top of the shell wall (1), a cover plate (3) is sealed and fixed to the opening, and a pole (31) is provided on the cover plate (3); The other end of the bare battery cell (6) is electrically connected to a second busbar (4), and the second busbar (4) is electrically connected to the pole (31).

13. The battery cell according to claim 12, characterized in that: The second busbar (4) comprises a third annular connecting portion (41), an electrical connecting piece (42) extending outward from the third annular connecting portion (41), and the electrical connecting piece (42) is electrically connected to the pole (31).

14. The battery cell according to claim 1, characterized in that The inner shell wall (2) is provided with a hole (21), and the hole (21) extends along the axis of the inner shell wall (2).

15. The battery cell according to claim 14, characterized in that The hole (21) is a heat dissipation hole.

16. The battery cell according to claim 15, characterized in that The cross section of the hole (21) 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 (1) and / or the inner shell wall (2) 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 (6) 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 (21) 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 (3).

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 (21).

21. A ring-shaped battery, characterized in that: A battery cell comprising any one of claims 1-20.

22. The annular battery according to claim 21, characterized in that The outer shell wall (1) and the inner shell wall (2) are arranged to form a cavity for accommodating the bare battery core (6), and the cross-sectional shape of the cavity is annular.

23. A battery, characterized in that: Comprising the annular battery as claimed in claim 21 or 22.

24. A battery module, characterized in that: The method comprises a plurality of annular batteries as claimed in claim 21 or 22, 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 23, wherein the plurality of batteries are connected in series and / or in parallel.

25. An electrical device, characterized in that: Comprising a plurality of annular batteries as claimed in claim 21 or 22; or, comprising a plurality of batteries as claimed in claim 23; or, comprising a battery module as claimed in claim 24.

26. A welding device for preparing a battery cell according to any one of claims 1 to 20, or preparing a ring-shaped battery according to claim 21 or 22, or preparing a battery according to claim 23, characterized in that: The welding device comprises a first welding head (101) and a second welding head (102) for moving toward each other, the first welding head (101) comprising an annular welding portion (1011), the annular welding portion (1011) being used to extend into the first gap (K1) and press the second electrical connection portion and the bottom of the shell wall (1) toward the second welding head (102), so that the second electrical connection portion is at least partially welded to the bottom of the shell wall (1).

27. The welding device according to claim 26, characterized in that A plurality of welding protrusions (1012) are provided on the side of the annular welding portion (1011) facing the second welding head (102), and the plurality of welding protrusions (1012) are evenly arranged along the circumference of the annular welding portion (1011).

Images