Battery unit, annular battery, battery, battery module, and electrical device

Abstract

A battery unit, an annular battery, a battery, a battery module, and an electrical device. The battery unit comprises a battery casing (1), the battery casing (1) comprising an outer casing wall (11) and an inner casing wall (12) disposed within the outer casing wall (11), a portion of a tube wall of the inner shell wall (12) protruding inwards to form a buffer part (121), and an outward-facing side of the buffer part (121) forming a buffer space (122). A bare cell (5) is sleeved between the outer casing wall (11) and the inner casing wall (12). The problem of expansion and deformation of a battery casing (1) caused by deformation of a bare cell (5) can be alleviated.

Description

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

[0001] This application is based on Chinese patent applications with application number 202311183212.3 and application date September 13, 2023, and application number 202322491533.1 and application date September 13, 2023, and claims the priority of these two Chinese patent applications. The entire contents of the two Chinese patent applications are hereby introduced into this application as a reference. Technical Field

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

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

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

[0005] At present, cylindrical batteries basically adopt a fully closed structure. As the energy density and power density of lithium-ion batteries become higher and higher, the charge and discharge rates are also getting higher and higher. During the charge and discharge process, the heat generation rate of the bare cells in the battery also increases accordingly. As the heat generation of the bare cells increases, the bare cells will undergo thermal expansion. The thermal expansion of the bare cells will squeeze the battery shell outward, causing the battery shell to expand and deform outward.

[0006] Summary of the Invention

[0007] The utility model provides a battery unit, a ring-shaped battery, a battery, a battery module and an electrical device, which are used to at least alleviate the problem of expansion and deformation of a battery shell caused by deformation of a bare battery core.

[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, a portion of the inner shell wall protruding inwardly to form a buffer portion, and a buffer space formed on an outward side of the buffer portion;

[0010] The bare battery cell is sleeved between the outer shell wall and the inner shell wall.

[0011] As an implementation manner, the outer shell wall and the inner shell wall are integrally connected, or the outer shell wall and the inner shell wall are fixed by welding.

[0012] As an implementation method, two or more buffer portions are provided in the circumferential direction of the inner shell wall.

[0013] As an implementation manner, the two or more buffer portions are evenly arranged in the circumferential direction.

[0014] As an implementation manner, in an orthographic projection perpendicular to the axis of the inner shell wall, the shape of the buffer space is a triangle, a quadrilateral, a polygon, an arc or a U-shape.

[0015] As an implementation method, at least one buffer portion is provided in the axial direction of the inner shell wall.

[0016] As an implementation method, a buffer portion is provided in the axial direction of the inner shell wall, and the buffer portion passes through both ends of the inner shell wall.

[0017] As an implementation manner, the buffer portion extends along a straight line or along a spiral line.

[0018] As an implementable manner, a protective cover is further included, which is passed through the outer side of the inner shell wall and is located between the inner shell wall and the bare battery cell, and a buffer gap is provided between the protective cover and the inner shell wall.

[0019] As an implementable manner, the minimum straight-line distance from the central axis of the bare cell to the outer wall of the bare cell is a first distance, and the width of the buffer gap is 0.01-0.1 times of the first distance.

[0020] As an implementation manner, the width of the buffer gap is positively correlated with the first distance.

[0021] As an implementation manner, the protective cover is a flexible protective cover.

[0022] As an implementable manner, the bare battery cell and the protective cover are interference fit.

[0023] As an implementation manner, a plurality of through holes are provided on the side wall of the protective cover.

[0024] As an implementable method, it also includes a first busbar arranged at the bottom of the outer shell wall, the first busbar includes an electrode connecting portion and a first tab connecting portion, the first tab connecting portion is used to electrically connect the tab at one end of the bare battery cell, the electrode connecting portion is at least partially located in the buffer space, and at least part of the electrode connecting portion located in the buffer space is electrically connected to the bottom of the outer shell wall.

[0025] As an implementable manner, the electrode connecting parts are provided in a one-to-one correspondence in each of the buffer spaces, and at least a portion of each of the electrode connecting parts is located in the corresponding buffer space.

[0026] As an implementation manner, the electrode connecting portion is provided with an overload narrowing area.

[0027] As an implementable manner, the overload narrowing zone includes a narrowing hole provided in the electrode connecting portion, and / or a narrowing groove provided on an edge of the electrode connecting portion.

[0028] As an implementation method, an insulating gasket is provided between the bottom of the outer shell wall and the first busbar, and in an orthographic projection perpendicular to the axis of the inner shell wall, the first tab connection portion and the overload narrowing zone are both located within the insulating gasket.

[0029] 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.

[0030] As an implementation manner, in the orthographic projection, the outer edge of the insulating layer coincides with the outer edge of the insulating gasket, or is located inside the outer edge of the insulating gasket.

[0031] As an implementation manner, in the axial direction of the inner shell wall, the buffer portion passes through both ends of the inner shell wall.

[0032] As an implementation manner, the electrode connecting portion is fixed to the bottom of the shell wall by welding, and, in an orthographic projection perpendicular to the axial direction, the welding position is located within the buffer space.

[0033] As an implementable method, a second bus is provided at the end of the bare cell facing away from the first bus, and the second bus includes a second pole tab connection portion and a pole post connection portion; the second pole tab connection portion is electrically connected to the pole tab of the bare cell, and the pole post connection portion is electrically connected to the pole post of the battery unit.

[0034] As an implementable manner, a cooling column is further included. The cooling column is inserted into the inner shell wall. A groove is provided on the side of the cooling column. The buffer portion is at least partially located in the groove.

[0035] As an implementable manner, a heat-conducting bushing is provided between the inner wall of the inner shell wall and the outer wall of the cooling column, and the heat conductivity of the heat-conducting bushing is greater than or equal to the heat conductivity of the cooling column.

[0036] 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.

[0037] As an implementation manner, the wall thickness of the buffer portion is less than or equal to the wall thickness of the remaining parts of the inner shell wall.

[0038] As an implementation manner, the outer shell wall and the inner shell wall are coaxially arranged.

[0039] 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.

[0040] As an implementable manner, the hole is a heat dissipation hole.

[0041] As an implementation manner, the cross section of the hole is a circle, a regular polygon, an ellipse or a non-equilateral polygon.

[0042] 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.

[0043] As an implementable manner, the cross section of the bare cell is a circle, a regular polygon, an ellipse or a non-equilateral polygon.

[0044] As an implementable manner, the maximum straight-line distance between any two points on the hole cross section is 0.11-0.65 of the maximum straight-line distance between any two points on the shell wall cross section.

[0045] In a second aspect, the present invention provides a ring-shaped battery comprising the above-mentioned battery unit.

[0046] 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.

[0047] In a third aspect, the present invention provides a battery, including the above-mentioned annular battery.

[0048] 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.

[0049] 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.

[0050] In the above scheme, a buffer space is formed on the outward side of the buffer portion of the inner shell wall. When the bare battery cell expands due to temperature increase, the inner side of the bare battery cell squeezes the inner shell wall. Due to the existence of the buffer space, after the inner shell wall is squeezed, it will deform and shrink in the radial direction to offset the radial inward deformation of the bare battery cell, thereby avoiding the situation where the bare battery cell can only expand outward in the radial direction due to the rigid structure of the inner shell wall that cannot be deformed, causing the battery shell to deform outward. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] 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:

[0052] FIG1 is a perspective view of a battery provided in an embodiment of the present invention;

[0053] FIG2 is a top view of FIG1 ;

[0054] FIG3 is a cross-sectional view of the AA portion of FIG2;

[0055] FIG4 is a partial enlarged view of portion I in FIG3 ;

[0056] FIG5 is a cross-sectional view of the BB portion of FIG3 ;

[0057] FIG6 is a perspective view of a battery housing according to an embodiment of the present invention;

[0058] FIG7 is a perspective view of a battery housing according to another embodiment of the present invention;

[0059] FIG8 is a schematic full cross-sectional view of a battery housing along its axis provided by an embodiment of the present invention;

[0060] FIG9 is a schematic full cross-sectional view of a battery housing along its axis according to another embodiment of the present invention;

[0061] FIG10 is a perspective view of a protective cover provided in an embodiment of the present invention;

[0062] FIG11 is a front view of a first busbar provided in an embodiment of the present invention;

[0063] FIG12 is a front view of a first busbar provided by another embodiment of the present invention;

[0064] FIG13 is a cross-sectional view corresponding to the portion AA in FIG2 provided by another embodiment of the present invention;

[0065] FIG14 is a cross-sectional view corresponding to the AA portion in FIG2 provided by another embodiment of the present invention;

[0066] FIG15 is a cross-sectional view corresponding to the AA portion in FIG2 provided by another embodiment of the present invention;

[0067] FIG16 is a schematic diagram of the assembly of the second busbar and the end cover provided in an embodiment of the present invention.

[0068] Explanation of the accompanying drawings: battery shell 1, outer shell wall 11, inner shell wall 12, buffer part 121, buffer space 122, hole 123, end cover 2, pole 21, injection hole 22, cooling column 3, thermal conductive bushing 4, bare battery cell 5, protective cover 6, through hole 61, first bus bar 7, electrode connecting part 71, first pole ear connecting part 72, narrowing hole 73, narrowing groove 74, insulating gasket 8, insulating layer 9, second bus bar 10, second pole ear connecting part 101, pole connecting part 102, explosion-proof valve 20. DETAILED DESCRIPTION

[0069] The present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the relevant invention and are not intended to limit the invention. It should also be noted that, for ease of description, only portions relevant to the invention are shown in the accompanying drawings.

[0070] 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.

[0071] 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.

[0072] As shown in FIG1 to FIG6 , the battery unit provided by the embodiment of the present invention includes:

[0073] The battery housing 1 includes an outer shell wall 11 and an inner shell wall 12 arranged inside the outer shell wall 11. Part of the tube wall of the inner shell wall 12 protrudes inward to form a buffer portion 121, and a buffer space 122 is formed on the outward side of the buffer portion 121.

[0074] In the example shown in FIG6 , two buffer portions 121 and buffer spaces 122 are provided on the circumference of the inner shell wall 12; in the example shown in FIG7 , four buffer portions 121 and buffer spaces 122 are provided on the circumference of the inner shell wall 12; of course, in other examples, other numbers of buffer portions 121 and buffer spaces 122 may also be provided.

[0075] In the case where two or more buffer portions 121 and buffer spaces 122 are provided, the two or more buffer portions 121 and buffer spaces 122 are evenly arranged in the circumferential direction of the inner shell wall 12 .

[0076] Generally, the battery housing 1 can be made of metal, such as steel, aluminum, and aluminum alloy, etc. On the one hand, it can protect the bare battery cell 5 disposed therein, and on the other hand, it can also serve as one of the poles of the battery, such as the negative pole or the positive pole.

[0077] At least one end of the battery housing 1 is open, and an end cover 2 can be welded to the opening. The end cover 2 can be provided with a pole 21, a liquid injection hole 22, etc.

[0078] The outer shell wall 11 and the inner shell wall 12 can both be annular structures, with the inner shell wall 12 defining a centrally located hole 123 (as shown in FIG. 8 or FIG. 9 ). This hole 123 serves as a heat dissipation hole. Referring to at least FIG. 3 , the outer shell wall 11 and the inner shell wall 12 can be a one-piece structure, such as by casting or stamping a single metal plate. Furthermore, referring to FIG. 13 , FIG. 14 , or FIG. 15 , the outer shell wall 11 and the inner shell wall 12 can also be a two-piece structure, where the outer shell wall 11 and the inner shell wall 12 are two separate components. For example, the inner shell wall 12 and the outer shell wall 11 can be connected by welding. When the bottom of the outer shell wall 11 has a bottom plate, the inner shell wall 12 can be directly welded to the bottom plate of the outer shell wall 11, and the bottom plate of the outer shell wall 11 is provided with a hole connected to the hole 123; if the outer shell wall 11 is only an annular wall, the inner shell wall 12 can be connected to the outer shell wall 11 with the help of an end cover, for example, one end of the inner shell wall 12 is welded to the end cover, and the end cover is welded to one end of the outer shell wall 11. At this time, one end of the end cover can be provided with a hole connected to the hole 123.

[0079] In this embodiment, specifically, the cross-section of the outer shell wall 11 can be a circle, a regular polygon, an ellipse, or a non-equilateral polygon. Correspondingly, the cross-section of the inner shell wall 12 can also be a circle, a regular polygon, an ellipse, or a non-equilateral polygon. The cross-section of the hole 123 can also be a circle, a regular polygon, an ellipse, or a non-equilateral polygon. The cross-section of the bare cell 5 can also be a circle, a regular polygon, an ellipse, or a non-equilateral polygon.

[0080] For example, but not limited to, a portion of the inner shell wall 12 can be stamped in the radial direction to form an inwardly protruding buffer portion 121, and a buffer space 122 can be formed on the outward side of the buffer portion 121. The buffer space 122 can be considered a groove-like structure. In other examples, the inner shell wall 12 can also be made of a tubular profile, including an inwardly protruding wall, which forms the buffer portion 121, and the outward side of the buffer portion 121 encloses the buffer space 122.

[0081] The bare battery cell 5 is sleeved between the outer shell wall 11 and the inner shell wall 12 .

[0082] It should be noted that a cavity is formed between the outer shell wall 11 and the inner shell wall 12 , and the cross-sectional shape of the cavity is preferably annular. The cavity at least serves as an installation space for the bare battery cell 5 , and the bare battery cell 5 is located in the installation space.

[0083] The bare cell 5 referred to here can be a wound cell, which is composed of a positive electrode sheet, a separator, and a negative electrode sheet stacked in sequence. The three-layer structure is wound to form a bare cell 5 with a hole in the center. The inner shell wall 12 is inserted into the hole in the center of the bare cell 5.

[0084] In the above solution, a buffer space 122 is formed on the outward side of the buffer portion 121 of the inner shell wall 12. When the bare cell 5 expands due to the increase in temperature, the inner side of the bare cell 5 squeezes the inner shell wall 12. Due to the existence of the buffer space 122, after the inner shell wall 12 is squeezed, it will deform and shrink in the radial direction to offset the radial inward deformation of the bare cell 5, thereby avoiding the situation where the inner shell wall 12 is a rigid structure and cannot be deformed, resulting in the bare cell 5 only being able to expand outward in the radial direction, causing the battery case 1 to deform outward. In addition, by providing the buffer space 122, the bare cell 5 can be partially placed in the buffer space 122 when it expands, and the deformation of the bare cell 5 can also be offset.

[0085] In addition, part of the tube wall of the inner shell wall 12 protrudes inward to form a buffer portion 121. By providing the buffer portion 121, on the one hand, the surface area of ​​the inner side of the inner shell wall 12 can be increased, which is beneficial to improving the heat dissipation capacity of the center of the inner shell wall 12 and facilitating heat dissipation in the middle of the battery. On the other hand, a buffer space 122 can be formed on the outward side of the buffer portion 121. The buffer space 122 can be used to store a certain amount of electrolyte to increase the electrolyte retention without increasing the battery volume.

[0086] As an implementation, in an orthographic projection perpendicular to the axis of the inner shell wall 12, the shape of the buffer space 122 is triangular, quadrilateral, polygonal, arc-shaped, or U-shaped. In this example, the shape of the buffer space 122 is quadrilateral, specifically, rectangular; that is, the buffer space 122 is a groove with a rectangular cross-section.

[0087] As an implementation method, at least one buffer portion 121 is provided in the axial direction of the inner shell wall 12 .

[0088] As shown in FIG8 , a buffer portion 121 is provided in the axial direction of the inner shell wall 12 ; as shown in FIG9 , two buffer portions 121 are provided in the axial direction of the inner shell wall 12 ; of course, in other examples, other numbers of buffer portions 121 may be provided in the axial direction of the inner shell wall 12 .

[0089] As an implementation method, a buffer portion 121 is provided in the axial direction of the inner shell wall 12 , and the buffer portion 121 passes through both ends of the inner shell wall 12 .

[0090] The buffer portion 121 passes through both ends of the inner shell wall 12. On the one hand, it is convenient for the welding needle of the subsequent welding equipment to extend into the bottom of the outer shell wall 11 from the buffer space 122 on the back of the buffer portion 121 to weld the first bus 7 described below to the bottom of the outer shell wall 11. In addition, it is convenient for the cooling column 3 to be set up later to be inserted into the inner shell wall 12 along the buffer portion 121, and the inner shell wall 12 is used to limit the rotation of the cooling column 3.

[0091] As an implementation manner, the buffer portion 121 extends along a straight line or a spiral line.

[0092] When the buffer portion 121 extends along a straight line, the straight line along which it extends is parallel to the axis of the inner shell wall 12 , so that the cooling column 3 to be assembled subsequently can be inserted into the inner shell wall 12 along the straight line.

[0093] When the buffer portion 121 extends along the spiral line, the cooling column 3 to be assembled later can be rotated and inserted into the inner shell wall 12 .

[0094] As an achievable method, referring to at least Figures 3 and 10 , a protective cover 6 is further included, which is passed through the outside of the inner shell wall 12 and is located between the inner shell wall 12 and the bare battery cell 5. A buffer gap is provided between the protective cover 6 and the inner shell wall 12; the length of the protective cover 6 is less than the length of the inner shell wall 12.

[0095] The protective cover 6 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 6 is generally the same as the cross-sectional shape of the inner shell wall 12. Of course, in some examples, the cross-sectional shape may be different. In this example, the cross-sectional shape of the protective cover 6 is circular.

[0096] The protective sleeve 6 is passed through the outer side of the inner shell wall 12 , and the protective sleeve 6 and the inner shell wall 12 are gap-fitted to form a buffer gap between the protective sleeve 6 and the inner shell wall 12 .

[0097] The protective cover 6 is used to support and protect the inner side of the bare battery cell 5 .

[0098] Generally, the protective cover 6 is an insulating protective cover. For example, the protective cover 6 may be made of insulating paper, rubber, or plastic. Preferably, the protective cover 6 has a certain degree of flexibility, that is, the protective cover 6 is flexible. This facilitates the protective cover 6 to deform toward the inner shell wall 12 as the bare cell 5 thermally expands. This avoids the protective cover 6 being a rigid structure, which would prevent the bare cell 5 from thermally expanding toward the inner shell wall 12 and cause the bare cell 5 to thermally expand toward the outer shell wall 11, resulting in outward deformation of the outer shell wall 11.

[0099] At least referring to FIG10 , in addition to buffering at least a portion of the thermal expansion and deformation of the bare cell 5, the buffer gap can also accommodate a portion of the electrolyte. In order to allow the electrolyte to flow on both sides of the protective cover 6, a plurality of through holes 61 are provided on the side wall of the protective cover 6, so that the electrolyte in the buffer gap can flow toward the bare cell 5 through the through holes 61, and can also flow from the bare cell 5 toward the buffer gap.

[0100] In order to allow the electrolyte at different positions in the buffer gap and the electrolyte inside the bare battery cell 5 to flow more evenly, the plurality of through holes 61 are evenly arranged on the side wall of the protective cover 6 .

[0101] Wherein, at least some of the through holes 61 have the same or different shapes and / or sizes. In this example, all of the through holes 61 have the same shape and size, and can be circular through holes. In other examples, the through holes 61 can also be elliptical holes, square holes, and other structural forms.

[0102] As an achievable embodiment, the minimum straight-line distance between the central axis of the bare cell 5 and the outer wall of the bare cell 5 is a first distance, and the width of the buffer gap is 0.01-0.1 times the first distance. Setting the width of the buffer gap to 0.01-0.1 times the first distance ensures that the buffer gap has sufficient buffer distance to offset the thermal expansion of the bare cell 5, while ignoring the adverse effect of setting the buffer gap on the battery energy density.

[0103] As an implementable manner, the width of the buffer gap is positively correlated with the first distance. That is, the larger the first distance of the bare cell 5, the larger the buffer gap is set to match the increase in the first distance of the bare cell 5 and the corresponding increase in its thermal expansion.

[0104] As an achievable method, the bare cell 5 and the protective cover 6 are interference fit. When assembling the battery, the protective cover 6 can be first inserted into the hole in the center of the bare cell 5. Since the bare cell 5 and the protective cover 6 are interference fit, the two can be assembled into the battery casing 1 together, which can improve the assembly efficiency. Moreover, since the center hole of the bare cell 5 is provided with the protective cover 6 when the bare cell 5 is installed into the battery casing 1, the protective cover 6 can prevent the center hole of the bare cell 5 from colliding with the shell wall 11 during the assembly process, causing damage to the center of the bare cell 5 and causing a short circuit.

[0105] As an implementable method, it also includes a first busbar 7 arranged at the bottom of the outer shell wall 11, the first busbar 7 includes a first pole tab connection part 72 and an electrode connection part 71, the first pole tab connection part 72 is used to electrically connect the pole tab at one end of the bare battery cell 5, the electrode connection part 71 is at least partially located in the buffer space 122, and at least part of the electrode connection part 71 located in the buffer space 122 is electrically connected to the bottom of the outer shell wall 11.

[0106] For example, the first tab connection portion 72 of the first bus 7 is welded and fixed to the tab at one end of the bare cell 5, and the electrode connection portion 71 is welded and fixed to the bottom of the outer shell wall 11 in the buffer space 122; that is, the tab at one end of the bare cell 5 is electrically connected to the bottom of the outer shell wall 11 through the first bus 7, and the outer shell wall 11 serves as one of the poles of the battery, such as the positive pole or the negative pole.

[0107] By at least partially disposing the electrode connecting portion 71 of the first busbar 7 electrically connected to the bare battery cell 5 in the buffer space 122, the welding needle of the welding equipment extends from the buffer space 122 to the bottom of the outer shell wall 11, and the end of the welding needle is in the buffer space 122, pressing the electrode connecting portion 71 against the bottom of the outer shell wall 11 to weld the electrode connecting portion 71 to the bottom of the outer shell wall 11, which can improve the welding quality of the electrode connecting portion 71 and the bottom of the outer shell wall 11, thereby improving the reliability of the connection between the electrode connecting portion 71 and the bottom of the outer shell wall 11, avoiding the separation of the electrode connecting portion 71 from the bottom of the outer shell wall 11, and causing the problem of electrical connection failure. Therefore, at least the reliability of the electrical connection between one pole of the bare battery cell 5 and the battery shell 1 is improved.

[0108] As an implementable manner, the electrode connecting parts 71 are provided in each of the buffer spaces 122 in a one-to-one correspondence, and at least a portion of each of the electrode connecting parts 71 is located in the corresponding buffer space 122 .

[0109] By providing multiple electrode connection portions 71, the size of a single electrode connection portion 71 can be reduced while still meeting the current transmission requirements between the first tab connection portion 72 and the housing wall 11. As the size of a single electrode connection portion 71 is reduced, the current required for its fusing is also correspondingly reduced. Therefore, based on the specific circumstances of the battery, the size of a single electrode connection portion 71 can be designed so that it can be fusing at a current that exceeds a small percentage of the rated current of the single electrode connection portion 71, thereby improving safety performance. The rated current of a single electrode connection portion 71 can be considered to be the current value of the maximum rated current of the battery divided by the number of electrode connection portions 71. The proportion of the fusing current of a single electrode connection portion 71 that exceeds the rated current of the single electrode connection portion 71 can be determined based on actual circumstances, and can be, for example, but not limited to, 5%, 8%, 10%, etc., of the rated current of the single electrode connection portion 71.

[0110] As an implementation method, the electrode connecting portion 71 is provided with an overload narrowing area.

[0111] By setting an overload narrowing zone in the electrode connection part 71, during the charging and discharging process, if the current increases abnormally, the electrode connection part 71 will melt in the overload narrowing zone, causing the first pole ear connection part 72 of the bus and the electrode connection part 71 to be short-circuited, that is, one of the poles of the battery is in a short-circuit state, which can avoid the bare battery cell 5 from heating up too high due to excessive current and causing combustion, explosion, etc. Therefore, by setting an overload narrowing zone in the electrode connection part 71, the safety of the battery can be improved.

[0112] As an implementation method, as shown in FIG11 , the overload narrowing zone includes a narrowing hole 73 provided in the electrode connecting portion 71 . As shown in FIG12 , the overload narrowing zone includes a narrowing groove 74 provided at the edge of the electrode connecting portion 71 .

[0113] As shown in FIG11 , the overload narrowing area is a narrowing hole 73 provided in the electrode connecting portion 71 . The narrowing hole 73 may be a through hole or a blind hole, and a through hole is preferably used.

[0114] As shown in FIG. 12 , the overload narrowing region is a narrowing groove 74 provided at the edge of the electrode connecting portion 71 .

[0115] As an implementation method, an insulating gasket 8 is provided between the bottom of the outer shell wall 11 and the first busbar 7 , and in the orthographic projection perpendicular to the axis of the inner shell wall 12 , the first tab connection portion 72 and the overload narrowing zone are both located within the insulating gasket 8 .

[0116] By providing an insulating gasket 8 between the first busbar 7 and the bottom of the outer shell wall 11, the battery shell 1 and the first busbar 7 can be in an open-circuit state after the electrode is connected to the overload narrowing area and melts due to an abnormal increase in current in the battery. At this time, one of the poles of the bare battery cell 5 connected to the first busbar 7 is also in an open-circuit state with the battery shell 1, avoiding further aggravation of the fault.

[0117] In addition to providing an insulating gasket 8 between the first busbar 7 and the bottom of the shell wall 11 so that the shell and the first busbar 7 are in an open-circuit state after the electrode connection is melted in the overload narrowing zone, an insulating layer 9 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 11, which are not listed here one by one.

[0118] As an achievable method, at least as shown in FIG3 , 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 cell 5 , and is wrapped around the outer side of the bottom of the bare cell 5 .

[0119] With the above structure, the outer side of the first busbar 7 and the bottom of the bare cell 5 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 cell 5 are insulated from the inner side of the outer shell wall 11. In the case where the electrode connection is melted in the overload narrowing zone, the fault will not be further aggravated due to the electrical connection between the outer side of the first busbar 7 and the outer side of the bare cell 5 and the inner side of the outer shell wall 11.

[0120] As an implementation manner, in the orthographic projection, the outer edge of the insulating layer 9 coincides with the outer edge of the insulating gasket 8 , or is located within the outer edge of the insulating gasket 8 .

[0121] 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 5 and the inner side of the outer shell wall 11, thereby avoiding the occurrence of conductive connection between the outer side of the first bus 7 and the outer side of the bare battery cell 5 and the inner side of the outer shell wall 11.

[0122] As an implementation method, in the axial direction of the inner shell wall 12 , the buffer portion 121 passes through both ends of the inner shell wall 12 .

[0123] As an implementable method, a second busbar 10 is provided at the end of the bare cell 5 facing away from the first busbar 7, as shown in Figure 16, the second busbar 10 includes a second pole tab connection portion 101 and a pole connection portion 102; the second pole tab connection portion 101 is electrically connected to the pole tab of the bare cell 5, and the pole connection portion 102 is electrically connected to the pole 21 of the battery.

[0124] For example, the second busbar 10 is welded and fixed to the tab at the other end of the bare cell 5 and the pole 21 connected to the cover plate 2 .

[0125] As an implementable manner, the second tab connection portion 101 is an annular connection portion, and a pole connection portion 102 extends outward from the second tab connection portion 101 . The pole connection portion 102 may be an electrical connection piece electrically connected to the pole 21 .

[0126] When making the connection, the second pole ear connection part 101 can be welded to the pole ear at the other end of the bare battery cell 5 first, and then the pole connection part 102 can be welded to the back of the pole 21 on the cover plate 2. Then, the cover plate 2 can be flipped over and covered on the opening of the battery shell 1, and then the end cover 2 can be welded to the outer shell wall 11.

[0127] As an implementable manner, an explosion-proof valve 20 is further provided on the end cover 2 .

[0128] As an implementable manner, a cooling column 3 is further included. The cooling column 3 is inserted into the inner shell wall 12 . A groove is provided on the side of the cooling column 3 , and the buffer portion 121 is at least partially located in the groove.

[0129] The cooling column 3 is inserted into the inner shell wall 12 and can exchange heat with the inner shell wall 12. At least part of the heat in the middle of the battery is transferred to the cooling column 3 through the inner shell wall 12. The cooling column 3 is used to transfer heat to the outside of the battery to achieve the purpose of heat dissipation in the middle of the battery.

[0130] By inserting the cooling column 3 in the inner shell wall 12, the heat in the middle of the battery can be transferred to the outside of the battery through the cooling column 3 to dissipate the heat in the middle of the battery, thereby improving the heat dissipation performance of the battery. On the basis of the improved heat dissipation performance, the battery size can be further increased. In addition, the temperature of the battery will not become high due to poor heat dissipation, so that the battery can operate in a more ideal temperature environment. The activity of the active material in the battery is high, so the electrical performance of the battery can be improved. In addition, since the battery will not have the problem of high temperature, the problem of battery combustion or even explosion due to high temperature is avoided, thereby improving the safety performance.

[0131] As an implementable manner, a heat-conducting bushing 4 is provided between the inner wall of the inner shell wall 12 and the outer wall of the cooling column 3 , and the heat conductivity of the heat-conducting bushing 4 is greater than or equal to the heat conductivity of the cooling column 3 .

[0132] By arranging a heat-conducting bushing 4 between the inner wall of the inner shell wall 12 and the outer wall of the cooling column 3, the heat generated inside the battery can be transferred from the inner shell wall 12 to the heat-conducting bushing 4, and then transferred from the bushing to the cooling column 3, and finally transferred from the cooling column 3 to the outside of the battery to dissipate heat from the battery.

[0133] The thermal conductivity of the thermally conductive bushing 4 is equal to or greater than that of the cooling pillars 3. Furthermore, it conforms to the inner shell wall 12 and the cooling pillars 3, thereby avoiding the problem of reduced heat transfer efficiency caused by the presence of air between the inner shell wall 12 and the cooling pillars 3. In this solution, the use of the thermally conductive bushing 4 improves heat transfer efficiency and enhances heat dissipation performance for the battery.

[0134] As an implementation manner, one end of the inner shell wall 12 is closed and the other end is open; or, both ends of the inner shell wall 12 are open.

[0135] Among them, at least as shown in Figure 15, the above-mentioned inner shell wall 12 itself can be closed at one end and open at the other end to form a hole 123 in the form of a blind hole, and a cooling column 3 is inserted in the hole 123 to dissipate heat to the middle part of the battery; in other examples, at least as shown in Figure 14, the above-mentioned inner shell wall 12 itself can be open at both ends, and one end thereof can be closed by other external components. For example, one end thereof is closed by the battery end cover or the bottom plate of the outer shell wall 11 to form a blind hole, which can be used as the hole 123, and a cooling column 3 is inserted in the hole 123 to dissipate heat to the middle part of the battery.

[0136] Of course, in other examples, at least as shown in FIG. 13 , both ends of the inner shell wall 12 are open to form a through hole, which can be used as a hole 123 , in which a cooling column 3 is inserted to dissipate heat from the middle of the battery.

[0137] As an implementable manner, the maximum straight-line distance between any two points on the cross section of the hole 123 is 0.11-0.65 of the maximum straight-line distance between any two points on the cross section of the shell wall 11 .

[0138] As an implementable manner, the maximum straight-line distance between any two points on the cross section of the hole 123 is 5 mm to 30 mm.

[0139] As an implementable manner, the maximum straight-line distance between any two points on the cross section of the hole 123 is 8 mm to 25 mm.

[0140] As an implementable manner, the maximum straight-line distance between any two points on the cross section of the hole 123 is 10 mm to 15 mm.

[0141] For example, but not limited to, the maximum straight-line distance between any two points on the cross section of the hole 123 is 5.15 mm, 5.3 mm, 6.25 mm, 7 mm, 8.66 mm, 13 mm, 15.35 mm, 18.7 mm, 19 mm, 22.9 mm, 24 mm, 28.4 mm, 29.46 mm, etc. The maximum straight-line distance between any two points on the cross section of the hole 123 can be determined according to actual needs, as long as it satisfies that the maximum straight-line distance between any two points on the cross section of the hole 123 is 0.11-0.65 of the maximum straight-line distance between any two points on the cross section of the outer shell wall 11 of the battery 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 123 can be selected. That is, the maximum straight-line distance between any two points on the cross section of the hole 123 is positively correlated with the length of the battery cell, so that the cooling column 3 can fully exchange heat within the hole 123, thereby removing heat from the center of the battery cell to the greatest extent possible, thereby improving the heat dissipation effect on the battery cell.

[0142] As an implementation method, the wall thickness of the buffer portion 121 is less than or equal to the wall thickness of the remaining parts of the inner shell wall 12 .

[0143] As an implementation manner, the outer shell wall 11 and the inner shell wall 12 are coaxially arranged.

[0144] In a second aspect, the utility model provides a ring-shaped battery, which includes the above-mentioned battery cell, and the cross-sectional shape of the cavity formed by the outer shell wall 11 and the inner shell wall 12 of the battery cell included in the ring-shaped battery is ring-shaped, so that the ring-shaped battery with the battery cell is a ring-shaped battery as a whole.

[0145] In a third aspect, the present invention provides a battery comprising the above-mentioned annular battery, so as to achieve better heat dissipation of the middle portion of the battery through the heat dissipation holes.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] Electrical equipment includes, but is not limited to, new energy vehicles (electric vehicles, hybrid vehicles, etc.), digital products, etc.

[0151] 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.

[0152] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the inventive concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A battery cell, characterized in that: include: A battery housing (1), the battery housing (1) comprising an outer shell wall (11) and an inner shell wall (12) arranged inside the outer shell wall (11), a portion of the tube wall of the inner shell wall (12) protruding inwardly to form a buffer portion (121), and a buffer space (122) formed on an outward side of the buffer portion (121); The bare battery core (5) is sleeved between the outer shell wall (11) and the inner shell wall (12).

2. The battery cell according to claim 1, characterized in that: The outer shell wall (11) and the inner shell wall (12) are integrally connected, or the outer shell wall (11) and the inner shell wall (12) are fixed by welding.

3. The battery cell according to claim 1, characterized in that Two or more buffer portions (121) are provided in the circumferential direction of the inner shell wall (12).

4. The battery cell according to claim 3, characterized in that: The two or more buffer portions (121) are evenly arranged in the circumferential direction.

5. The battery cell according to any one of claims 1 to 4, characterized in that: In an orthographic projection perpendicular to the axis of the inner shell wall (12), the shape of the buffer space (122) is a triangle, a quadrilateral, a polygon, an arc or a U shape.

6. The battery cell according to any one of claims 1 to 4, characterized in that: One or more buffer portions (121) are provided in the axial direction of the inner shell wall (12).

7. The battery cell according to claim 6, characterized in that: A buffer portion (121) is provided in the axial direction of the inner shell wall (12), and the buffer portion (121) passes through both ends of the inner shell wall (12).

8. The battery cell according to claim 7, characterized in that: The buffer portion (121) extends along a straight line or along a spiral line.

9. The battery cell according to any one of claims 1 to 4, characterized in that: It also comprises a protective sleeve (6), the protective sleeve (6) being arranged on the outside of the inner shell wall (12) and being located between the inner shell wall (12) and the bare battery core (5), and a buffer gap being arranged between the protective sleeve (6) and the inner shell wall (12).

10. The battery cell according to claim 9, characterized in that: The minimum straight-line distance from the central axis of the bare battery core (5) to the outer wall of the bare battery core (5) is a first distance, and the width of the buffer gap is 0.01-0.1 times of the first distance.

11. The battery cell according to claim 10, characterized in that: The width of the buffer gap is positively correlated with the first distance.

12. The battery cell according to claim 9, characterized in that: The protective cover (6) is a flexible protective cover.

13. The battery cell according to claim 9, characterized in that: The bare battery core (5) and the protective cover (6) are interference fit.

14. The battery cell according to any one of claims 10 to 13, characterized in that: A plurality of through holes (61) are provided on the side wall of the protective sleeve (6).

15. The battery cell according to claim 3 or 4, characterized in that: It also includes a first busbar (7) arranged at the bottom of the shell wall (11), the first busbar (7) including an electrode connecting portion (71) and a first pole lug connecting portion (72), the first pole lug connecting portion (72) being used to electrically connect to a pole lug at one end of the bare battery cell (5), the electrode connecting portion (71) being at least partially located in the buffer space (122), and at least a portion of the electrode connecting portion (71) located in the buffer space (122) being electrically connected to the bottom of the shell wall (11).

16. The battery cell according to claim 15, characterized in that The electrode connecting parts (71) are arranged in a one-to-one correspondence in each of the buffer spaces (122), and at least a portion of each of the electrode connecting parts (71) is located in the corresponding buffer space (122).

17. The battery cell according to claim 15, characterized in that The electrode connecting portion (71) is provided with an overload narrowing area.

18. The battery cell according to claim 17, characterized in that: The overload narrowing zone comprises a narrowing hole (73) arranged in the electrode connecting portion (71), and / or a narrowing groove (74) arranged at the edge of the electrode connecting portion (71).

19. The battery cell according to claim 17, characterized in that: An insulating gasket (8) is provided between the bottom of the outer shell wall (11) and the first busbar (7), and in an orthographic projection perpendicular to the axis of the inner shell wall (12), the first pole lug connection portion (72) and the overload narrowing zone are both located within the insulating gasket (8).

20. The battery cell according to claim 19, 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 (5), and covers the outer side of the bottom of the bare battery cell (5).

21. The battery cell according to claim 20, characterized in that In the orthographic projection, the outer edge of the insulating layer (9) coincides with the outer edge of the insulating gasket (8), or is located within the outer edge of the insulating gasket (8).

22. The battery cell according to claim 15, characterized in that In the axial direction of the inner shell wall (12), the buffer portion (121) passes through both ends of the inner shell wall (12).

23. The battery cell according to claim 22, characterized in that The electrode connecting portion (71) is fixed to the bottom of the shell wall (11) by welding, and, in an orthographic projection perpendicular to the axial direction, the welding position is located within the buffer space (122).

24. The battery cell according to claim 15, characterized in that A second busbar (10) is provided at one end of the bare cell (5) facing away from the first busbar (7); the second busbar (10) comprises a second pole lug connection portion (101) and a pole column connection portion (102); the second pole lug connection portion (101) is electrically connected to the pole lug of the bare cell (5), and the pole column connection portion (102) is electrically connected to the pole column (21) of the battery unit.

25. The battery cell according to any one of claims 1 to 4, characterized in that: It also comprises a cooling column (3), the cooling column (3) being inserted into the inner shell wall (12), a groove being provided on the side surface of the cooling column (3), and the buffer portion (121) being at least partially located in the groove.

26. The battery cell according to claim 25, characterized in that A heat-conducting bushing (4) is arranged between the inner wall of the inner shell wall (12) and the outer wall of the cooling column (3), and the heat conductivity of the heat-conducting bushing (4) is greater than or equal to the heat conductivity of the cooling column (3).

27. The battery cell according to any one of claims 1 to 4, 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.

28. The battery cell according to any one of claims 1 to 4, characterized in that: The wall thickness of the buffer portion (121) is less than or equal to the wall thickness of the remaining parts of the inner shell wall (12).

29. The battery cell according to any one of claims 1 to 4, characterized in that: The outer shell wall (11) and the inner shell wall (12) are coaxially arranged.

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

31. The battery cell according to claim 30, characterized in that The hole (123) is a heat dissipation hole.

32. The battery cell according to claim 30, characterized in that The cross section of the hole (123) is circular, regular polygonal, elliptical or non-equilateral polygonal.

33. The battery cell according to claim 1 or 32, 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.

34. The battery cell according to claim 1 or 30, characterized in that: The cross section of the bare battery core (5) is circular, regular polygonal, elliptical or non-equilateral polygonal.

35. The battery cell according to claim 30, characterized in that The maximum value of the straight-line distance between any two points on the cross section of the hole (123) is 0.11-0.65 of the maximum value of the straight-line distance between any two points on the cross section of the shell wall (11).

36. A ring-shaped battery, characterized in that: A battery cell comprising any one of claims 1-35.

37. The annular battery according to claim 36, characterized in that The outer shell wall (1) and the inner shell wall (12) are arranged to form a cavity for accommodating the bare battery core (5), and the cross-sectional shape of the cavity is annular.

38. A battery, characterized in that: Comprising the annular battery as described in claim 36 or 37.

39. A battery module, characterized in that: It comprises a plurality of annular batteries as claimed in claim 36 or 37, wherein the plurality of annular batteries are connected in series and / or in parallel; or it comprises a plurality of batteries as claimed in claim 38, wherein the plurality of batteries are connected in series and / or in parallel.

40. An electrical device, characterized in that: comprising a plurality of annular batteries as claimed in claim 36 or 37; or, comprising a plurality of batteries as claimed in claim 38; Or, comprising the battery module as described in claim 39.

Images