Battery cell and electric device

Abstract

Provided in the present application are a battery cell and an electric device. The battery cell comprises a laminated electrode assembly, wherein the electrode assembly comprises a plurality of first electrode sheets and a plurality of second electrode sheets, which are stacked in a first direction; a corner of each first electrode sheet has a first notch and a first empty foil area; a corner of each second electrode sheet has a second notch and a second empty foil area; when observed in the first direction, the first empty foil area at least partially overlaps with the second notch, the second empty foil area at least partially overlaps with the first notch, and the first empty foil area is spaced apart from the second empty foil area; and a plurality of first empty foil areas are stacked in the first direction, and a plurality of second empty foil areas are stacked in the first direction. Therefore, a space that is reserved between the electrode assembly and a housing and used for accommodating the first empty foil areas and the second empty foil areas can be reduced, the energy density of the battery cell can be improved, and when the battery cell is subjected to an external force or falls, the electrode assembly is less likely to shake relative to the housing, and the battery cell is also less likely to experience a short circuit.

Description

Battery cells and electrical equipment CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Chinese patent application CN 202410147486.5, entitled “Battery Cell and Electrical Equipment,” filed on February 1, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a battery cell and an electrical device. Background Art

[0003] With the rapid development of electronic information technology, various electronic devices are also developing towards intelligence and multi-functions, and the requirements for various battery performance are becoming higher and higher.

[0004] At present, the tab of the electrode assembly is generally led out from one end of the electrode sheet in the length direction, so that a large space needs to be reserved between the shell for accommodating the electrode assembly and the end of the electrode assembly where the tab is set to accommodate the tab, which affects the energy density of the battery cell and causes the electrode assembly to shake easily relative to the shell when the battery cell is subjected to external force or falls, which may cause a short circuit between the tab and the electrode sheet, thereby increasing the risk of thermal runaway of the battery cell. Summary of the Invention

[0005] The present application provides a battery cell and electrical equipment, which can improve the energy density of the battery cell and reduce the possibility of battery cell short circuit.

[0006] In the first aspect, the present application provides a battery cell, including an electrode assembly, which is a laminated structure, and the electrode assembly includes a plurality of first pole pieces and a plurality of second pole pieces stacked along a first direction, and the first pole pieces and the second pole pieces have opposite polarity; a corner position of each first pole piece has a first notch and a first empty foil area, and a corner position of each second pole piece has a second notch and a second empty foil area, and when viewed along the first direction, the first empty foil area and the second notch at least partially overlap, the second empty foil area and the first notch at least partially overlap, and the first empty foil area and the second empty foil area are spaced apart; the first empty foil areas of the plurality of first pole pieces are stacked along the first direction, and the second empty foil areas of the plurality of second pole pieces are stacked along the first direction.

[0007] In the above technical solution, a corner position of each first electrode piece has a first notch and a first empty foil area, and a corner position of each second electrode piece has a second notch and a second empty foil area. When viewed along the first direction, the first empty foil area and the second notch at least partially overlap, and the second empty foil area and the first notch at least partially overlap, which can reduce the volume of the first empty foil area and the second empty foil area protruding from the first electrode piece and the second electrode piece. The space reserved between the electrode assembly and the shell for accommodating the first empty foil area and the second empty foil area is reduced, which can improve the energy density of the battery cell. When the battery cell is subjected to external force or falls, the electrode assembly is less likely to shake relative to the shell, and the possibility of short circuit between the first empty foil area and the second electrode piece, and the second empty foil area and the first electrode piece is also less. , thereby reducing the risk of thermal runaway of the battery cell, and the first empty foil area and the second empty foil area are located at the same corner of the electrode assembly, which can further reduce the space occupied by the first empty foil area and the second empty foil area, and further improve the capacity density of the battery cell; the first empty foil area and the second empty foil area are arranged at intervals, which can reduce the possibility of short circuit caused by contact between the first empty foil area and the second empty foil area; the first empty foil areas of the plurality of first pole pieces are stacked along the first direction, and the second empty foil areas of the plurality of second pole pieces are stacked along the first direction, which facilitates the connection of the plurality of first empty foil areas and the connection of the plurality of second empty foil areas, so that the external device can be electrically connected to the plurality of first pole pieces through the first empty foil area, and can be electrically connected to the plurality of second pole pieces through the second empty foil area.

[0008] In some embodiments of the present application, when viewed along the first direction, the first notch and the second notch partially overlap.

[0009] In the above technical solution, when viewed along the first direction, the first notch and the second notch partially overlap, which can reserve a spacing space between the first empty foil area and the second empty foil area, thereby reducing the possibility of short circuit caused by contact between the first empty foil area and the second empty foil area.

[0010] In some embodiments of the present application, the first pole piece has a first coating area, and along the length direction of the first pole piece, the first empty foil area does not exceed the first coating area, and along the width direction of the first pole piece, the first empty foil area does not exceed the first coating area; the second pole piece has a second coating area, along the length direction of the second pole piece, the second empty foil area does not exceed the second coating area, and along the width direction of the second pole piece, the second empty foil area does not exceed the second coating area.

[0011] In the above technical solution, along the length direction of the first electrode sheet, the first hollow foil area does not exceed the first coated area, and along the width direction of the first electrode sheet, the first hollow foil area does not exceed the first coated area. This ensures that the first hollow foil area does not protrude from the first electrode sheet, and there is no need to reserve space between the electrode assembly and the housing to accommodate the first hollow foil area. This can further improve the energy density of the battery cell. When the battery cell is subjected to external force or falls, the possibility of the electrode assembly shaking relative to the housing is further reduced, and the possibility of the first hollow foil area contacting and short-circuiting with the second electrode sheet is also further reduced, thereby further reducing the risk of thermal runaway of the battery cell.

[0012] Along the length direction of the second pole piece, the second empty foil area does not exceed the second coated area, and along the width direction of the second pole piece, the second empty foil area does not exceed the second coated area, so that the second empty foil area does not protrude from the second pole piece, and there is no need to reserve space between the electrode assembly and the shell to accommodate the second empty foil area, which can further improve the energy density of the battery cell. When the battery cell is subjected to external force or falls, the possibility of the electrode assembly shaking relative to the shell is further reduced, and the possibility of the second empty foil area contacting and short-circuiting with the first pole piece is also further reduced, thereby further reducing the risk of thermal runaway of the battery cell.

[0013] In some embodiments of the present application, the first coated area has a first edge in the length direction of the first pole piece, the first empty foil area has a second edge in the length direction of the first pole piece, and the first edge is flush with the second edge; and / or, the second coated area has a third edge in the width direction of the second pole piece, the second empty foil area has a fourth edge in the width direction of the second pole piece, and the third edge is flush with the fourth edge.

[0014] In the above technical solution, by making the first edge flush with the second edge, the preparation of the first empty foil area can be facilitated; by making the third edge flush with the fourth edge, the preparation of the second empty foil area can be facilitated.

[0015] In some embodiments of the present application, the interval between the first empty foil area and the second empty foil area is D1, which satisfies 0.4 mm ≤ D1 ≤ 1 mm.

[0016] In the above technical solution, when the spacing distance D1 between the first empty foil area and the second empty foil area is greater than or equal to 0.4 mm, the spacing distance between the first empty foil area and the second empty foil area can be larger, and the possibility of contact short circuit between the first empty foil area and the second empty foil area is smaller, which can reduce the risk of thermal runaway of the battery cell; when the spacing distance D1 between the first empty foil area and the second empty foil area is less than or equal to 1 mm, the spacing distance between the first empty foil area and the second empty foil area can be smaller, and the occupied spacing space is smaller, which is beneficial to improving the energy density of the battery cell; when the spacing distance D1 between the first empty foil area and the second empty foil area is 0.4 mm-1 mm, it can reduce the possibility of contact short circuit between the first empty foil area and the second empty foil area, reduce the risk of thermal runaway of the battery cell, and help improve the energy density of the battery cell.

[0017] In some embodiments of the present application, the battery cell further includes a first insulating member, and at least a portion of the first insulating member is disposed between the first empty foil area and the second empty foil area.

[0018] In the above technical solution, by arranging a first insulating member between the first empty foil area and the second empty foil area, the possibility of short circuit between the first empty foil area and the second empty foil area can be reduced, thereby reducing the risk of thermal runaway of the battery cell.

[0019] In some embodiments of the present application, the first insulating member wraps at least part of the plurality of first empty foil regions.

[0020] In the above technical solution, by making the first insulating member wrap at least part of the multiple first empty foil areas, the insulation effect between the first empty foil areas and the second empty foil areas can be improved, which can further reduce the possibility of short circuit between the first empty foil areas and the second empty foil areas, and thus further reduce the risk of thermal runaway of the battery cell.

[0021] In some embodiments of the present application, the battery cell further includes a shell, and the electrode assembly is arranged inside the shell; when viewed along the first direction, the first insulating member includes a first insulating portion and a second insulating portion, the first insulating portion is arranged between the first empty foil area and the second empty foil area, and the second insulating portion is arranged between the first empty foil area and the inner wall of the shell.

[0022] In the above technical solution, when observed along the first direction, the first insulating member includes a first insulating portion and a second insulating portion, the first insulating portion is arranged between the first empty foil area and the second empty foil area, and the second insulating portion is arranged between the first empty foil area and the inner wall of the shell, so that the first insulating portion can play an insulating role between the first empty foil area and the second empty foil area, and the second insulating portion can play an insulating role between the first empty foil area and the shell, thereby reducing the possibility of contact short circuit between the first empty foil area and the first empty foil area, and the first empty foil area and the shell, and reducing the risk of thermal runaway of the battery cell.

[0023] In some embodiments of the present application, the battery cell further includes an electrode terminal and a first adapter, the first adapter is connected to a plurality of first empty foil areas, the outer shell includes a first wall, the electrode terminal is arranged on the first wall, the second insulating portion is arranged between the first wall and the first empty foil area, and the electrode terminal passes through the second insulating portion and is connected to the first adapter.

[0024] In the above technical solution, the battery cell also includes an electrode terminal and a first adapter, the first adapter is connected to a plurality of first empty foil areas, the outer shell includes a first wall, the electrode terminal is arranged on the first wall, the second insulating portion is arranged between the first wall and the first empty foil area, the electrode terminal passes through the second insulating portion and is connected to the first adapter, so that the plurality of first empty foil areas can be electrically connected to an external device through the first adapter and the electrode terminal, and the second insulating portion can serve as an insulator between the electrode terminal and the outer shell, thereby reducing the possibility of contact short circuit between the first empty foil area and the outer shell, and reducing the risk of thermal runaway of the battery cell.

[0025] In some embodiments of the present application, the first insulating member further includes a third insulating portion, which is disposed on one side of the plurality of first empty foil areas along the first direction, and is connected to the first insulating portion and the second insulating portion.

[0026] In the above technical solution, by providing a third insulating portion, and making the third insulating portion provided on one side of the plurality of first empty foil areas along the first direction, the third insulating portion is connected to the first insulating portion and the second insulating portion, so as to play an insulating role for the first empty foil areas and the outer shell in the first direction, thereby reducing the possibility of contact short circuit between the first empty foil areas and the outer shell, and reducing the risk of thermal runaway of the battery cell.

[0027] In some embodiments of the present application, along the first direction, the first empty foil areas of the plurality of first pole pieces are gathered toward the middle to form a first gathered portion, and the third insulating portion supports the first gathered portion.

[0028] In the above technical solution, along the first direction, the first empty foil areas of the multiple first electrode sheets are gathered toward the middle to form a first gathered portion, which can make the connection method of the multiple first empty foil areas simpler and easier to operate, and facilitate the connection of the multiple first empty foil areas with the first adapter. It can also make the size of the first empty foil areas in their extension direction smaller, so that the space occupied by the first empty foil areas is smaller, which is beneficial to improving the energy density of the battery cell; the third insulating portion carries the first gathered portion, which can facilitate the connection of the first adapter with the electrode terminal.

[0029] In some embodiments of the present application, along the first direction, the second empty foil areas of the plurality of second pole pieces are gathered toward the middle to form a second gathered portion; the battery cell further includes a second adapter connecting the housing and the second gathered portion.

[0030] In the above technical solution, along the first direction, the second empty foil areas of the multiple second electrode sheets are gathered toward the middle to form a second gathered portion, and the battery cell also includes a second adapter, which connects the shell and the second gathered portion, so that the connection method of the multiple second empty foil areas is simpler and easier to operate, and it is convenient to connect the multiple second empty foil areas with the first adapter, and it can make the size of the second empty foil areas smaller in their extension direction, so that the space occupied by the second empty foil areas is smaller, which is beneficial to improving the energy density of the battery cell; and it enables the multiple second empty foil areas to be electrically connected to the external device through the second adapter and the shell.

[0031] In some embodiments of the present application, the second notch and the second empty foil area are located at one end of the second electrode sheet in the length direction; the battery cell also includes a shell, and the electrode assembly is accommodated in the shell. Along the length direction of the second electrode sheet, the distance between one end of the second electrode sheet where the second empty foil area and the second notch are provided and the inner wall of the shell is D2, satisfying 0.4mm≤D2≤1mm.

[0032] In the above technical solution, the second notch and the second empty foil area are located at one end of the second electrode sheet in the length direction, so that the first empty foil area and the second empty foil area can be led out from one end of the second electrode sheet in the length direction, which facilitates the electrical connection of the battery cell with the external device through the first empty foil area and the second empty foil area; when along the length direction of the second electrode sheet, the distance D2 between the end of the second electrode sheet where the second empty foil area and the second notch are provided and the inner wall of the shell is greater than or equal to 0.4 mm, it is convenient to assemble the electrode assembly and the shell, and it is convenient for the shell to accommodate the electrolyte; when along the length direction of the second electrode sheet, the distance D2 between the end of the second electrode sheet where the second empty foil area and the second notch are provided and the inner wall of the shell is less than or equal to 1 mm, which can make the spacing between the electrode assembly and the shell smaller and the energy density of the battery cell higher; therefore, when along the length direction of the second electrode sheet, the distance D2 between the end of the second electrode sheet where the second empty foil area and the second notch are provided and the inner wall of the shell is 0.4 mm-1 mm, it is convenient to assemble the electrode assembly and the shell, and it is convenient for the shell to accommodate the electrolyte, and it can also make the energy density of the battery cell higher.

[0033] In some embodiments of the present application, the first notch is arranged in a triangular shape; and / or the second notch is arranged in a triangular shape.

[0034] In the above technical solution, the first notch is arranged in a triangular shape, which is convenient for the preparation of the first notch, and the first notch occupies a smaller space, which is beneficial to improving the energy density of the battery cell; the second notch is arranged in a triangular shape, which is convenient for the preparation of the second notch, and the second notch occupies a smaller space.

[0035] In some embodiments of the present application, the first empty foil area is arranged in a triangular shape; and / or the second empty foil area is arranged in a triangular shape.

[0036] In the above technical solution, the first empty foil area is arranged in a triangular shape, which is convenient for the preparation of the first empty foil area and the folding of multiple first empty foil areas, and the first empty foil area occupies a smaller space, which is beneficial to improving the energy density of the battery cell; the second empty foil area is arranged in a triangular shape, which is convenient for the preparation of the second empty foil area and the folding of multiple second empty foil areas, and the second empty foil area occupies a smaller space, which is beneficial to improving the energy density of the battery cell.

[0037] In some embodiments of the present application, the first electrode is a positive electrode, and the second electrode is a negative electrode.

[0038] In a second aspect, the present application provides an electrical device, which includes the battery cell as described above, and the battery cell is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can also be obtained based on these drawings.

[0040] FIG1 is a schematic diagram of the three-dimensional structure of a battery cell provided in some embodiments of the present application;

[0041] FIG2 is a schematic diagram of an exploded structure of a battery cell provided in some embodiments of the present application;

[0042] FIG3 is a schematic diagram of an exploded structure of an electrode assembly of a battery cell provided in some embodiments of the present application;

[0043] FIG4 is a schematic structural diagram of a first electrode piece of a battery cell provided in some embodiments of the present application;

[0044] FIG5 is a schematic structural diagram of a second pole piece of a battery cell provided in some embodiments of the present application;

[0045] FIG6 is a partially enlarged schematic diagram of a partial structure of a battery cell provided in some embodiments of the present application;

[0046] FIG7 is a schematic structural diagram of a battery cell provided in some embodiments of the present application from one perspective;

[0047] FIG8 is a partially enlarged schematic diagram of a structure of a battery cell provided in some embodiments of the present application;

[0048] FIG9 is a partially enlarged schematic diagram of the cross-sectional structure of the battery cell along the AA direction in FIG7 ;

[0049] FIG10 is a partially enlarged schematic diagram of the cross-sectional structure of the battery cell along the BB direction in FIG7 ;

[0050] FIG11 is a partially enlarged schematic diagram of a cross-sectional structure of a battery cell provided in some other embodiments of the present application;

[0051] FIG12 is a partially enlarged schematic diagram of the cross-sectional structure of the battery cell along the CC direction in FIG7 ;

[0052] FIG13 is a schematic diagram of the structure of a diaphragm of a battery cell provided in some embodiments of the present application;

[0053] FIG14 is a partially enlarged schematic diagram of the cross-sectional structure of the battery cell along the EE direction in FIG7 .

[0054] Icons: 10-cell; 100-electrode assembly; 110-first electrode; 111-first notch; 112-first empty foil area; 112a-first gathered portion; 1121-second edge; 113-first coating area; 1131-first edge; 120-second electrode; 121-second notch; 122-second empty foil area; 122a-second gathered portion; 1221-fourth edge; 123-second coating area; 1231-third edge; 130 -diaphragm; 131 -third notch; 200 -first insulating member; 210 -first insulating portion; 220 -second insulating portion; 230 -third insulating portion; 300 -housing; 310 -shell; 311 -first wall; 312 -second wall; 320 -shell cover; 410 -electrode terminal; 420 -first adapter; 430 -second adapter; 440 -second insulating member; X -first direction; Y -length direction of first electrode piece; Z -width direction of first electrode piece.

[0055] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0056] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0057] The terms "first", "second" and the like in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0058] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0059] The "flush" in this application does not mean flush in the strict sense, but roughly flush. Taking into account the process tolerance, as long as the tolerance is within 0.2mm, it can be considered "flush".

[0060] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0061] The battery cell includes a casing and an electrode assembly. The electrode assembly is accommodated in the casing. The electrode assembly includes a pole piece and a tab. The tab generally extends out of the casing from one end of the pole piece in the longitudinal direction to connect to an external device. Therefore, a large space must be reserved between the casing and the end of the electrode assembly where the tab is set to accommodate the tab. This causes the space in the casing used to accommodate the pole piece to be compressed, affecting the energy density of the battery cell. In addition, due to the large spacing between the electrode assembly and the casing, the electrode assembly is prone to shaking relative to the casing when the battery cell is subjected to external force or falls. The tab is fixed relative to the casing, which may cause the tab to move relative to the pole piece, and then short-circuit with the pole piece, resulting in an increased risk of thermal runaway in the battery cell.

[0062] In order to improve the energy density of a battery cell and reduce the possibility of a short circuit in the battery cell, the present application provides a battery cell, which includes an electrode assembly. The electrode assembly is a laminated structure, and the electrode assembly includes a plurality of first pole pieces and a plurality of second pole pieces stacked along a first direction, and the first pole pieces have opposite polarity to the second pole pieces; a corner position of each first pole piece has a first notch and a first empty foil area, and a corner position of each second pole piece has a second notch and a second empty foil area. When viewed along the first direction, the first empty foil area and the second notch at least partially overlap, and the second empty foil area and the first notch at least partially overlap, and the first empty foil area and the second empty foil area are spaced apart; the first empty foil areas of the plurality of first pole pieces are stacked along the first direction, and the second empty foil areas of the plurality of second pole pieces are stacked along the first direction.

[0063] In a battery cell of this structure, a corner position of each first electrode piece has a first notch and a first empty foil area, and a corner position of each second electrode piece has a second notch and a second empty foil area. When viewed along the first direction, the first empty foil area and the second notch at least partially overlap, and the second empty foil area and the first notch at least partially overlap, which can reduce the volume of the first empty foil area and the second empty foil area protruding from the first electrode piece and the second electrode piece, and the space reserved between the electrode assembly and the shell for accommodating the first empty foil area and the second empty foil area is reduced, which can improve the energy density of the battery cell. When the battery cell is subjected to external force or falls, the electrode assembly is less likely to shake relative to the shell, and the possibility of short circuit between the first empty foil area and the second electrode piece, and the second empty foil area and the first electrode piece is also less. The first empty foil area and the second empty foil area are located at the same corner of the electrode assembly, which can further reduce the space occupied by the first empty foil area and the second empty foil area, and further improve the capacity density of the battery cell; the first empty foil area and the second empty foil area are arranged at intervals, which can reduce the possibility of short circuit caused by contact between the first empty foil area and the second empty foil area; the first empty foil areas of the plurality of first pole pieces are stacked along the first direction, and the second empty foil areas of the plurality of second pole pieces are stacked along the first direction, which facilitates the connection of the plurality of first empty foil areas and the connection of the plurality of second empty foil areas, so that the external device can be electrically connected to the plurality of first pole pieces through the first empty foil area, and can be electrically connected to the plurality of second pole pieces through the second empty foil area.

[0064] The battery cells provided in the embodiments of the present application may be secondary batteries or primary batteries, such as lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, and are not limited in this embodiment. The electrochemical devices may be cylindrical, flat, rectangular, or in other shapes, and are not limited in this embodiment.

[0065] The embodiments of the present application provide an electrical device that uses a battery cell as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, and the like.

[0066] Referring to Figures 1 to 5, Figure 1 is a schematic diagram of the three-dimensional structure of the battery cell provided in some embodiments of the present application, Figure 2 is a schematic diagram of the exploded structure of the battery cell provided in some embodiments of the present application, Figure 3 is a schematic diagram of the exploded structure of the electrode assembly of the battery cell provided in some embodiments of the present application, Figure 4 is a schematic diagram of the structure of the first electrode piece of the battery cell provided in some embodiments of the present application, and Figure 5 is a schematic diagram of the structure of the second electrode piece of the battery cell provided in some embodiments of the present application.

[0067] An embodiment of the present application provides a battery cell 10, which includes an electrode assembly 100. The electrode assembly 100 is a laminated structure. The electrode assembly 100 includes a plurality of first electrode sheets 110 and a plurality of second electrode sheets 120 stacked along a first direction X. The first electrode sheets 110 and the second electrode sheets 120 have opposite polarities. A corner of each first electrode sheet 110 has a first notch 111 and a first empty foil area 112. A corner of each second electrode sheet 120 has a second notch 121 and a second empty foil area 122. When viewed along the first direction X, the first empty foil area 112 and the second notch 121 at least partially overlap, and the second empty foil area 122 and the first notch 111 at least partially overlap. The first empty foil area 112 and the second empty foil area 122 are alternately arranged. The first empty foil areas 112 of the plurality of first electrode sheets 110 are stacked along the first direction X, and the second empty foil areas 122 of the plurality of second electrode sheets 120 are stacked along the first direction X.

[0068] By making a corner of each first electrode sheet 110 have a first notch 111 and a first empty foil area 112, and a corner of each second electrode sheet 120 have a second notch 121 and a second empty foil area 122, when viewed along the first direction X, the first empty foil area 112 and the second notch 121 at least partially overlap, and the second empty foil area 122 and the first notch 111 at least partially overlap, the volume of the first empty foil area 112 and the second empty foil area 122 protruding from the first electrode sheet 110 and the second electrode sheet 120 can be reduced, and the space reserved between the electrode assembly 100 and the shell 300 for accommodating the first empty foil area 112 and the second empty foil area The reduced space between the electrode assembly 122 can improve the energy density of the battery cell 10. When the battery cell 10 is subjected to external force or falls, the electrode assembly 100 is less likely to shake relative to the housing 300. The possibility of short circuit between the first empty foil area 112 and the second electrode sheet 120, and between the second empty foil area 122 and the first electrode sheet 110 is also less, thereby reducing the risk of thermal runaway of the battery cell 10. The first empty foil area 112 and the second empty foil area 122 are located at the same corner of the electrode assembly 100, which can further reduce the space occupied by the first empty foil area 112 and the second empty foil area 122, and further improve the energy density of the battery cell 10. The first empty foil area 112 and the second empty foil area 122 are arranged at intervals, which can reduce the possibility of short circuit caused by contact between the first empty foil area 112 and the second empty foil area 122. The first empty foil areas 112 of the multiple first pole pieces 110 are stacked along the first direction X, and the second empty foil areas 122 of the multiple second pole pieces 120 are stacked along the first direction X, so as to facilitate the connection of the multiple first empty foil areas 112 and the connection of the multiple second empty foil areas 122, so that the external device can be electrically connected to the multiple first pole pieces 110 through the first empty foil areas 112, and can be electrically connected to the multiple second pole pieces 120 through the second empty foil areas 122.

[0069] In some embodiments, when viewed along the first direction X, the first notch 111 and the second notch 121 partially overlap.

[0070] By making the first notch 111 and the second notch 121 partially overlap when viewed along the first direction X, a spacing space can be reserved between the first empty foil area 112 and the second empty foil area 122, thereby reducing the possibility of the first empty foil area 112 and the second empty foil area 122 contacting each other and causing a short circuit.

[0071] In some embodiments, the first electrode 110 has a first coating area 113 . Along the length direction Y of the first electrode, the first empty foil area 112 does not exceed the first coating area 113 . Along the width direction Z of the first electrode, the first empty foil area 112 does not exceed the first coating area 113 .

[0072] The first coating region 113 may refer to a region coated with an active material, or may refer to a region coated with other coatings such as ceramics.

[0073] By ensuring that the first empty foil area 112 does not exceed the first coated area 113 along the length direction Y of the first electrode sheet, and does not exceed the first coated area 113 along the width direction Z of the first electrode sheet, the first empty foil area 112 can be prevented from protruding from the first electrode sheet 110, and there is no need to reserve space between the electrode assembly 100 and the housing 300 to accommodate the first empty foil area 112, which can further improve the energy density of the battery cell 10. When the battery cell 10 is subjected to external force or falls, the possibility of the electrode assembly 100 shaking relative to the housing 300 is further reduced, and the possibility of the first empty foil area 112 contacting and short-circuiting with the second electrode sheet 120 is also further reduced, thereby further reducing the risk of thermal runaway of the battery cell 10.

[0074] In some embodiments, the second electrode 120 has a second coating area 123 . Along the length direction of the second electrode, the second empty foil area 122 does not exceed the second coating area 123 . Along the width direction of the second electrode, the second empty foil area 122 does not exceed the second coating area 123 .

[0075] By ensuring that the second empty foil area 122 does not exceed the second coated area 123 along the length direction of the second electrode sheet, and does not exceed the second coated area 123 along the width direction of the second electrode sheet, the second empty foil area 122 can be prevented from protruding from the second electrode sheet 120, and there is no need to reserve space between the electrode assembly 100 and the shell 300 to accommodate the second empty foil area 122, which can further improve the energy density of the battery cell 10. When the battery cell 10 is subjected to external force or falls, the possibility of the electrode assembly 100 shaking relative to the shell 300 is further reduced, and the possibility of the second empty foil area 122 contacting and short-circuiting with the first electrode sheet 110 is also further reduced, thereby further reducing the risk of thermal runaway of the battery cell 10.

[0076] In some embodiments, the length direction of the second pole piece is parallel to the length direction Y of the first pole piece, and the width direction of the second pole piece is parallel to the width direction Z of the first pole piece.

[0077] In some embodiments, the electrode includes a current collector and an active material layer. The coating area can refer to the area coated with active material, or it can refer to the area coated with other coatings, such as ceramic coating. The empty foil area is the area of ​​the current collector that is not coated with the active material layer.

[0078] In some embodiments, the first coating area 113 has a first edge 1131 in the length direction Y of the first electrode piece, and the first empty foil area 112 has a second edge 1121 in the length direction Y of the first electrode piece. The first edge 1131 is flush with the second edge 1121 .

[0079] By making the first edge 1131 flush with the second edge 1121 , the preparation of the first empty foil area 112 can be facilitated.

[0080] In some embodiments, the second coating area 123 has a third edge 1231 in the width direction of the second electrode piece, and the second empty foil area 122 has a fourth edge 1221 in the width direction of the second electrode piece. The third edge 1231 is flush with the fourth edge 1221 .

[0081] By making the third edge 1231 flush with the fourth edge 1221 , the preparation of the second empty foil area 122 can be facilitated.

[0082] See FIG6 , which is a partially enlarged schematic diagram of a partial structure of a battery cell provided in some embodiments of the present application.

[0083] In some embodiments, the distance between the first empty foil area 112 and the second empty foil area 122 is D1, which satisfies 0.4 mm ≤ D1 ≤ 1 mm. For example, D1 can be 0.4 mm, 0.7 mm, or 1 mm. The distance here refers to the distance between the shortest two points between the first empty foil area 112 and the second empty foil area 122.

[0084] When the spacing distance D1 between the first empty foil area 112 and the second empty foil area 122 is greater than or equal to 0.4 mm, the spacing distance between the first empty foil area 112 and the second empty foil area 122 can be larger, the possibility of contact short circuit between the first empty foil area 112 and the second empty foil area 122 is smaller, and the risk of thermal runaway of the battery cell 10 can be reduced; when the spacing distance D1 between the first empty foil area 112 and the second empty foil area 122 is less than or equal to 1 mm, the spacing distance between the first empty foil area 112 and the second empty foil area 122 can be smaller, the occupied spacing space is smaller, which is beneficial to improving the energy density of the battery cell 10; when the spacing distance D1 between the first empty foil area 112 and the second empty foil area 122 is 0.4 mm-1 mm, the possibility of contact short circuit between the first empty foil area 112 and the second empty foil area 122 can be smaller, the risk of thermal runaway of the battery cell 10 is reduced, and the energy density of the battery cell 10 is improved.

[0085] 7 and 8 , FIG7 is a schematic structural diagram of a battery cell provided in some embodiments of the present application from one perspective, and FIG8 is a schematic structural diagram of a partially enlarged portion of a battery cell provided in some embodiments of the present application.

[0086] In some embodiments, the battery cell 10 further includes a first insulating member 200 , and at least a portion of the first insulating member 200 is disposed between the first empty foil area 112 and the second empty foil area 122 .

[0087] By providing the first insulating member 200 between the first empty foil area 112 and the second empty foil area 122 , the possibility of short circuit between the first empty foil area 112 and the second empty foil area 122 can be reduced, thereby reducing the risk of thermal runaway of the battery cell 10 .

[0088] In some embodiments, the first insulating member 200 may be made of a polymer insulating material such as polyethylene terephthalate (PET), polypropylene (PP), or polyethylene (PE).

[0089] In some embodiments, the first insulating member 200 wraps at least a portion of the plurality of first empty foil regions 112 .

[0090] By wrapping at least part of the first empty foil areas 112 with the first insulating member 200, the insulation effect between the first empty foil areas 112 and the second empty foil areas 122 can be improved, and the possibility of short circuit between the first empty foil areas 112 and the second empty foil areas 122 can be further reduced, thereby further reducing the risk of thermal runaway of the battery cell 10.

[0091] 8 to 10 , FIG9 is a partially enlarged schematic diagram of the cross-sectional structure of the battery cell in FIG7 along the AA direction, and FIG10 is a partially enlarged schematic diagram of the cross-sectional structure of the battery cell in FIG7 along the BB direction.

[0092] In some embodiments, the battery cell 10 further includes a housing 300, and the electrode assembly 100 is disposed within the housing 300. Viewed along the first direction X, the first insulating member 200 includes a first insulating portion 210 and a second insulating portion 220. The first insulating portion 210 is disposed between the first hollow foil region 112 and the second hollow foil region 122, and the second insulating portion 220 is disposed between the first hollow foil region 112 and the inner wall of the housing 300.

[0093] When observed along the first direction X, the first insulating member 200 includes a first insulating portion 210 and a second insulating portion 220. The first insulating portion 210 is arranged between the first empty foil area 112 and the second empty foil area 122, and the second insulating portion 220 is arranged between the first empty foil area 112 and the inner wall of the shell 300, so that the first insulating portion 210 can play an insulating role between the first empty foil area 112 and the second empty foil area 122, and the second insulating portion 220 can play an insulating role between the first empty foil area 112 and the shell 300, thereby reducing the possibility of contact short circuit between the first empty foil area 112 and the first empty foil area 112, and the first empty foil area 112 and the shell 300, thereby reducing the risk of thermal runaway of the battery cell 10.

[0094] In some embodiments, the shell 300 can be made of a material with higher strength, such as metal materials such as steel, aluminum alloy, etc., so that the shell 300 has higher acceptance performance, and thus the shell 300 is not easily deformed or damaged due to force or environmental changes, thereby making the battery cell 10 more reliable.

[0095] In other embodiments, the housing 300 may also be made of non-metallic materials with relatively high strength, such as carbon fiber, hard plastic, etc.

[0096] In some embodiments, the battery cell 10 further includes an electrode terminal 410 and a first adapter 420, the first adapter 420 is connected to a plurality of first empty foil areas 112, the outer shell 300 includes a first wall 311, the electrode terminal 410 is arranged on the first wall 311, the second insulating portion 220 is arranged between the first wall 311 and the first empty foil area 112, and the electrode terminal 410 passes through the second insulating portion 220 and is connected to the first adapter 420.

[0097] By connecting the first adapter 420 to the multiple first empty foil areas 112, the shell 300 includes a first wall 311, the electrode terminal 410 is arranged on the first wall 311, and the second insulating part 220 is arranged between the first wall 311 and the first empty foil area 112. The electrode terminal 410 passes through the second insulating part 220 and is connected to the first adapter 420, so that the multiple first empty foil areas 112 can be electrically connected to the external device through the first adapter 420 and the electrode terminal 410. The second insulating part 220 can play an insulating role between the electrode terminal 410 and the shell 300, reducing the possibility of contact short circuit between the first empty foil area 112 and the shell 300, and reducing the risk of thermal runaway of the battery cell 10.

[0098] In some embodiments, the first adapter 420 is bent, a portion of the first adapter 420 is perpendicular to the first wall 311 , facilitating connection with the first empty foil area 112 , and another portion of the first adapter 420 is parallel to the first wall 311 , facilitating connection with the electrode terminal 410 .

[0099] In some embodiments, part of the first adapter 420 is disposed between two adjacent first empty foil areas 112 , which can increase the connection area between the first adapter 420 and the first empty foil areas 112 and improve the connection reliability.

[0100] In some other embodiments, the first adapter 420 may also be disposed on one side of the plurality of first empty foil areas 112 along the first direction X.

[0101] In some embodiments, the battery cell 10 further includes a second insulating member 440 , which is disposed between the electrode terminal 410 and the outer side of the first wall 311 .

[0102] By providing the second insulating member 440 between the electrode terminal 410 and the outer side of the first wall 311 , the possibility of short circuiting between the electrode terminal 410 and the housing 300 can be reduced, thereby reducing the risk of thermal runaway of the battery cell 10 .

[0103] In some embodiments, the second insulating member 440 may be made of a polymer insulating material such as polyethylene terephthalate (PET), polypropylene (PP), or polyethylene (PE).

[0104] In some embodiments, the first insulating member 200 further includes a third insulating portion 230 . The third insulating portion 230 is disposed on one side of the plurality of first empty foil areas 112 along the first direction X. The third insulating portion 230 is connected to the first insulating portion 210 and the second insulating portion 220 .

[0105] By providing the third insulating portion 230 and making the third insulating portion 230 provided on one side of the plurality of first empty foil areas 112 along the first direction X, the third insulating portion 230 is connected to the first insulating portion 210 and the second insulating portion 220, thereby being able to insulate the first empty foil areas 112 and the outer shell 300 in the first direction X, thereby reducing the possibility of contact short circuit between the first empty foil areas 112 and the outer shell 300, and reducing the risk of thermal runaway of the battery cell 10.

[0106] In some embodiments, along the first direction X, the first empty foil areas 112 of the plurality of first electrode sheets 110 are gathered toward the middle to form a first gathered portion 112 a.

[0107] By making the first empty foil areas 112 of the multiple first electrode sheets 110 converge toward the middle to form the first converged portion 112a along the first direction X, the connection method of the multiple first empty foil areas 112 can be simpler and easier to operate, and the multiple first empty foil areas 112 can be easily connected to the first adapter 420. Since some first empty foil areas 112 need to be bent and extended to a certain length before they can be connected to adjacent first empty foil areas 112, by making the multiple first empty foil areas 112 converge toward the middle, the size of the first empty foil areas 112 in their extension direction (i.e., the vertical direction of the bent edge of the first empty foil areas 112) can be made smaller, so that the space occupied by the first empty foil areas 112 is smaller, which is beneficial to improving the energy density of the battery cell 10.

[0108] Refer to FIG11 , which is a partially enlarged schematic diagram of the cross-sectional structure of a battery cell provided in some other embodiments of the present application.

[0109] In some other embodiments, the third insulating portion 230 supports the first gathered portion 112 a .

[0110] The outer shell 300 includes a shell 310 and a cover 320. During assembly of the battery cell 10, the electrode assembly 100 must first be installed in the shell 310. After the first adapter 420 is connected to the electrode terminal 410, the cover 320 is placed on the shell 310. However, since the first gusseted portion 112a is suspended after the electrode assembly 100 is installed in the shell 310, the connection between the first adapter 420 and the electrode terminal 410 may cause the first gusseted portion 112a to be shifted due to force, affecting the connection between the first adapter 420 and the electrode terminal 410. Therefore, by having the third insulating portion 230 support the first gusseted portion 112a, the connection between the first adapter 420 and the electrode terminal 410 can be facilitated.

[0111] Referring to FIG12 , FIG12 is a partially enlarged schematic diagram of the cross-sectional structure of the battery cell along the CC direction in FIG7 .

[0112] In some embodiments, the second hollow foil areas 122 of the plurality of second electrode sheets 120 converge toward the middle to form a second converged portion 122a along the first direction X. The battery cell 10 further includes a second adapter 430 , which connects the housing 300 and the second converged portion 122a.

[0113] By making the second empty foil areas 122 of the plurality of second electrode sheets 120 converge toward the middle along the first direction X to form a second converged portion 122a, the battery cell 10 further includes a second adapter 430, which connects the housing 300 and the second converged portion 122a, so that the connection method of the plurality of second empty foil areas 122 is simpler and easier to operate, and facilitates the connection of the plurality of second empty foil areas 122 with the first adapter 420, and can make the size of the second empty foil areas 122 in the extension direction thereof smaller, so that the space occupied by the second empty foil areas 122 is smaller, which is beneficial to improving the energy density of the battery cell 10; and the plurality of second empty foil areas 122 can be electrically connected to an external device through the second adapter 430 and the housing 300.

[0114] In some embodiments, the housing 300 includes a second wall 312 , and the second adapter 430 is connected to the second wall 312 .

[0115] In some embodiments, the second adapter 430 is bent, a portion of the second adapter 430 is perpendicular to the second wall 312 to facilitate connection with the second empty foil area 122, and another portion of the second adapter 430 is parallel to the second wall 312 to facilitate connection with the second wall 312.

[0116] In some embodiments, part of the second adapter 430 is disposed between two adjacent second empty foil areas 122 , which can increase the connection area between the second adapter 430 and the second empty foil areas 122 and improve the connection reliability.

[0117] In some other embodiments, the second adapter 430 may also be disposed on one side of the plurality of second empty foil areas 122 along the first direction X.

[0118] See FIG13 , which is a schematic structural diagram of a diaphragm of a battery cell provided in some embodiments of the present application.

[0119] In some embodiments, the electrode assembly 100 further includes a diaphragm 130, which is disposed between the first electrode piece 110 and the second electrode piece 120. The diaphragm 130 has a third notch 131. Along the first direction X, the first empty foil area 112 at least partially overlaps with the third notch 131, and the second empty foil area 122 at least partially overlaps with the third notch 131.

[0120] By making the first empty foil area 112 at least partially overlap with the third notch 131 and the second empty foil area 122 at least partially overlap with the third notch 131 along the first direction X, the third notch 131 can be used to accommodate the first empty foil area 112 and the second empty foil area 122, which can facilitate the connection of multiple first empty foil areas 112 and multiple second empty foil areas 122.

[0121] Referring to FIG14 , FIG14 is a partially enlarged schematic diagram of the cross-sectional structure of the battery cell along the EE direction in FIG7 .

[0122] In some embodiments, the second notch 121 and the second hollow foil region 122 are located at one end of the second electrode sheet in the longitudinal direction. The battery cell 10 further includes a housing 300, and the electrode assembly 100 is housed within the housing 300. Along the longitudinal direction of the second electrode sheet, the distance D2 between the end of the second electrode sheet 120 where the second hollow foil region 122 and the second notch 121 are provided and the inner wall of the housing 300 satisfies 0.4 mm ≤ D2 ≤ 1 mm. For example, D2 can be 0.4 mm, 0.6 mm, or 1 mm.

[0123] By locating the second notch 121 and the second empty foil area 122 at one end of the second electrode in the longitudinal direction, the first empty foil area 112 and the second empty foil area 122 can be led out from one end of the second electrode in the longitudinal direction, thereby facilitating electrical connection of the battery cell 10 with an external device through the first empty foil area 112 and the second empty foil area 122. When, along the length direction of the second electrode sheet, the distance D2 between one end of the second electrode sheet 120 provided with the second empty foil area 122 and the second notch 121 and the inner wall of the shell 300 is greater than or equal to 0.4 mm, it can facilitate the assembly of the electrode assembly 100 and the shell 300 and facilitate the shell 300 to accommodate the electrolyte; when, along the length direction of the second electrode sheet, the distance D2 between one end of the second electrode sheet 120 provided with the second empty foil area 122 and the second notch 121 and the inner wall of the shell 300 is less than or equal to 1 mm, it can make the interval between the electrode assembly 100 and the shell 300 smaller and the energy density of the battery cell 10 higher; therefore, when, along the length direction of the second electrode sheet, the distance D2 between one end of the second electrode sheet 120 provided with the second empty foil area 122 and the second notch 121 and the inner wall of the shell 300 is 0.4 mm-1 mm, it can facilitate the assembly of the electrode assembly 100 and the shell 300 and facilitate the shell 300 to accommodate the electrolyte, and can also make the energy density of the battery cell 10 higher.

[0124] In some embodiments, the first notch 111 is arranged in a triangular shape.

[0125] By configuring the first notch 111 to be triangular, the preparation of the first notch 111 is facilitated, and the space occupied by the first notch 111 is small, which is beneficial to improving the energy density of the battery cell 10 .

[0126] In some embodiments, the second notch 121 is arranged in a triangular shape.

[0127] By configuring the second notch 121 to be triangular, the preparation of the second notch 121 is facilitated, and the space occupied by the second notch 121 is small.

[0128] In other embodiments, the first notch 111 and the second notch 121 may also be arranged in a trapezoidal shape.

[0129] In some embodiments, the first empty foil area 112 is arranged in a triangle shape.

[0130] By arranging the first empty foil area 112 in a triangular shape, the preparation of the first empty foil area 112 is facilitated, and the plurality of first empty foil areas 112 are facilitated to be folded together. In addition, the first empty foil area 112 occupies less space, which is beneficial to improving the energy density of the battery cell 10 .

[0131] In some embodiments, the third insulating portion 230 is arranged in a triangular shape, so that the first insulating member 200 can cover the first empty foil area 112 , and the first insulating member 200 occupies a smaller space, which is beneficial to improving the energy density of the battery cell 10 .

[0132] In some embodiments, the second empty foil area 122 is arranged in a triangle shape.

[0133] By arranging the second empty foil area 122 in a triangular shape, the preparation of the second empty foil area 122 is facilitated, and multiple second empty foil areas 122 are facilitated to be folded together. In addition, the second empty foil area 122 occupies less space, which is beneficial to improving the energy density of the battery cell 10.

[0134] In some embodiments, the first electrode 110 is a positive electrode, and the second electrode 120 is a negative electrode.

[0135] The battery cell 10 includes an electrode assembly 100, a housing 300 and an electrolyte, and the housing 300 is used to accommodate the electrode assembly 100 and the electrolyte. The electrode assembly 100 is composed of a positive electrode sheet, a negative electrode sheet and a separator. The battery cell 10 mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode collector. The part of the positive electrode collector that is not coated with the positive electrode active material layer serves as a positive electrode tab (i.e., the first empty foil area 112) to realize the input or output of electrical energy of the positive electrode sheet through the positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary material or lithium manganese oxide, etc. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The portion of the negative electrode current collector not coated with the negative electrode active material layer serves as the negative electrode tab (i.e., the second empty foil area 122), so that electrical energy can be input or output from the negative electrode sheet through the negative electrode tab. The negative electrode current collector can be made of copper, and the negative electrode active material can be made of carbon or silicon. The separator can be made of polypropylene (PP) or polyethylene (PE). The electrolyte can include an organic solvent, an electrolyte lithium salt, etc.

[0136] An embodiment of the present application provides an electrical device, which includes a battery cell 10 provided in any of the above embodiments, and the battery cell 10 is used to provide electrical energy.

[0137] The electrical device may be any of the aforementioned devices or systems using the battery cell 10 .

[0138] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0139] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery cell, characterized in that: The electrode assembly comprises an electrode assembly having a laminated structure, wherein the electrode assembly comprises a plurality of first pole pieces and a plurality of second pole pieces stacked along a first direction, wherein the first pole pieces and the second pole pieces have opposite polarities; Each of the first pole pieces has a first notch and a first empty foil area at one corner, and each of the second pole pieces has a second notch and a second empty foil area at one corner. When viewed along the first direction, the first empty foil area and the second notch at least partially overlap, and the second empty foil area and the first notch at least partially overlap, and the first empty foil area and the second empty foil area are spaced apart. The first empty foil areas of the plurality of first pole pieces are stacked along the first direction, and the second empty foil areas of the plurality of second pole pieces are stacked along the first direction.

2. The battery cell according to claim 1, characterized in that When viewed along the first direction, the first notch and the second notch partially overlap.

3. The battery cell according to claim 1, characterized in that The first pole piece has a first coating area, and along the length direction of the first pole piece, the first empty foil area does not exceed the first coating area, and along the width direction of the first pole piece, the first empty foil area does not exceed the first coating area; The second pole piece has a second coating area. Along the length direction of the second pole piece, the second empty foil area does not exceed the second coating area. Along the width direction of the second pole piece, the second empty foil area does not exceed the second coating area.

4. The battery cell according to claim 3, characterized in that The first coating area has a first edge in the length direction of the first pole piece, and the first empty foil area has a second edge in the length direction of the first pole piece, and the first edge is flush with the second edge; and / or, The second coating area has a third edge in the width direction of the second pole piece, the second hollow foil area has a fourth edge in the width direction of the second pole piece, and the third edge is flush with the fourth edge.

5. The battery cell according to claim 1, characterized in that The interval between the first empty foil area and the second empty foil area is D1, which satisfies 0.4 mm ≤ D1 ≤ 1 mm.

6. The battery cell according to any one of claims 1 to 5, characterized in that: The battery core further includes a first insulating member, at least a portion of which is disposed between the first empty foil area and the second empty foil area.

7. The battery cell according to claim 6, characterized in that The first insulating member wraps at least a portion of the plurality of the first empty foil regions.

8. The battery cell according to claim 6, characterized in that The battery cell further includes a shell, and the electrode assembly is disposed in the shell; Viewed along the first direction, the first insulating member includes a first insulating portion and a second insulating portion, the first insulating portion is arranged between the first empty foil area and the second empty foil area, and the second insulating portion is arranged between the first empty foil area and the inner wall of the shell.

9. The battery cell according to claim 8, characterized in that The battery cell also includes an electrode terminal and a first adapter, the first adapter is connected to the plurality of first empty foil areas, the outer shell includes a first wall, the electrode terminal is arranged on the first wall, the second insulating portion is arranged between the first wall and the first empty foil area, and the electrode terminal passes through the second insulating portion and is connected to the first adapter.

10. The battery cell according to claim 8, characterized in that: The first insulating member further includes a third insulating portion, which is disposed on one side of the plurality of first empty foil areas along the first direction and is connected to the first insulating portion and the second insulating portion.

11. The battery cell according to claim 10, characterized in that: Along the first direction, the first empty foil areas of the plurality of first pole pieces are gathered toward the middle to form a first gathered portion, and the third insulating portion supports the first gathered portion.

12. The battery cell according to any one of claims 1 to 5, characterized in that: Along the first direction, the second empty foil areas of the plurality of second pole pieces are gathered toward the middle to form a second gathered portion; the battery cell further comprises a second adapter connecting the housing and the second gathered portion.

13. The battery cell according to any one of claims 1 to 5, characterized in that: The second notch and the second empty foil area are located at one end of the second electrode in the length direction; The battery cell also includes a shell, and the electrode assembly is accommodated in the shell. Along the length direction of the second pole piece, the distance between the end of the second pole piece where the second hollow foil area and the second notch are provided and the inner wall of the shell is D2, satisfying 0.4mm≤D2≤1mm.

14. The battery cell according to any one of claims 1 to 5, characterized in that: The first notch is arranged in a triangular shape; and / or the second notch is arranged in a triangular shape.

15. The battery cell according to any one of claims 1 to 5, characterized in that: The first empty foil area is arranged in a triangular shape; and / or the second empty foil area is arranged in a triangular shape.

16. The battery cell according to any one of claims 1 to 5, characterized in that: The first pole piece is a positive pole piece, and the second pole piece is a negative pole piece.

17. An electrical device, characterized in that: The electrical device comprises the battery cell according to any one of claims 1 to 16, and the battery cell is used to provide electrical energy.

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