Battery cell, battery cell preparation method, and electrical device

Abstract

A battery cell and an electrical device. The battery cell comprises an electrode assembly. The electrode assembly comprises a plurality of first electrode sheets and a plurality of second electrode sheets stacked in a first direction. Each first electrode sheet comprises a first current collector and a first active material layer, the first current collector comprises a first main region and a first bare foil region, and the first bare foil region is located at a first corner position on the first electrode sheet. The first bare foil regions of the plurality of first electrode sheets are stacked in the first direction. When viewed in the first direction, at least a portion of the first bare foil region overlaps with a first notch of the second electrode sheet. An insulating adhesive layer is arranged on the first bare foil region and is connected to the first main region. The insulating adhesive layer can provide insulation between the first bare foil region and the second electrode sheet, thereby reducing the likelihood of thermal runaway in the battery cell. Moreover, the insulating adhesive layer is easy and low-cost to prepare, the operation of attaching the insulating adhesive layer to the first electrode sheet is simple, and the insulating adhesive layer can be attached along various shapes, resulting in broad applicability.

Description

Battery cell, method for preparing battery cell, and electrical equipment CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Chinese patent application CN 202410253433.1, entitled “Battery Cell, Method for Preparing Battery Cell, and Electrical Equipment,” filed on March 5, 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, a method for preparing the 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 safety requirements for batteries are becoming increasingly higher.

[0004] The electrode assembly includes two pole pieces with different polarities, each with a tab connected to it. Due to the different sizes of the two pole pieces, the projection of the tab connected to the smaller pole piece overlaps with the projection of the larger pole piece in the thickness direction of the electrode assembly. This may cause burrs on the end face of the smaller pole piece to short-circuit with the larger pole piece, causing thermal runaway of the battery cell. Therefore, an insulating layer must be provided at the edge of the tab. Currently, the insulating layer is generally made of ceramic materials, which are difficult and expensive to prepare, and can generally only be coated in a single direction, resulting in a limited range of application. Summary of the Invention

[0005] The present application provides a battery cell, a method for preparing the battery cell, and an electrical device, which can reduce the difficulty and cost of preparing the battery cell.

[0006] In a first aspect, the present application provides a battery cell, comprising an electrode assembly, wherein the electrode assembly is a laminated structure, the electrode assembly comprising a plurality of first electrode sheets and a plurality of second electrode sheets stacked along a first direction, wherein the first electrode sheets and the second electrode sheets have opposite polarities;

[0007] The first electrode sheet includes a first current collector and a first active material layer. The first current collector includes a first main body region and a first hollow foil region. The first main body region is provided with the first active material layer on the surface, and the first hollow foil region is not provided with the first active material layer on the surface. The first hollow foil regions of the plurality of first electrode sheets are stacked along a first direction.

[0008] The second electrode sheet has a first notch, and when viewed along the first direction, at least a portion of the first empty foil area overlaps with the first notch;

[0009] An insulating adhesive layer is provided on the first hollow foil area, and the insulating adhesive layer is connected to the first main body area.

[0010] In the above technical solution, the battery cell includes an electrode assembly, the electrode assembly is a laminated structure, the electrode assembly includes a plurality of first pole pieces and a plurality of second pole pieces stacked along a first direction, the first pole piece and the second pole piece have opposite polarity; the first pole piece includes a first current collector and a first active material layer, the first current collector includes a first main body area and a first empty foil area, the surface of the first main body area is provided with a first active material layer, and the surface of the first empty foil area is not provided with the first active material layer, the first empty foil areas of the plurality of first pole pieces are stacked along the first direction, so that the electrode assembly can be electrically connected to the load through the plurality of first empty foil areas; the second pole piece has a first notch, and when viewed along the first direction, at least part of the first empty foil area overlaps with the first notch, which can reduce the volume of the first empty foil area protruding from the first pole piece, and the space reserved between the electrode assembly and the battery cell shell for accommodating the first empty foil area is small, which can The energy density of the battery cell is improved, and 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 the first hollow foil area and the second electrode piece contacting and short-circuiting is also smaller, thereby reducing the risk of thermal runaway of the battery cell; an insulating adhesive layer is provided on the first hollow foil area, and the insulating adhesive layer is connected to the first main area, which can play an insulating role between the first hollow foil area and the second electrode piece, reducing the possibility of burrs on the end face of the second electrode piece extending beyond the first main area contacting and short-circuiting with the first hollow foil area, and for a battery cell structure with multiple first hollow foil areas connected together, the insulating adhesive layer can reduce the possibility of the first hollow foil area contacting and short-circuiting with the second electrode piece after being collapsed, thereby reducing the possibility of thermal runaway of the battery cell, and at the same time, the preparation difficulty and cost of the insulating adhesive layer are relatively low, the operation of attaching it to the first electrode piece is also relatively simple, and the insulating adhesive layer can be attached along different shapes, with a wide range of applications.

[0011] In some embodiments, the insulating adhesive layer is adjacent to the first main body region or covers a portion of the first main body region.

[0012] In the above technical solution, by making the insulating adhesive layer adjacent to the first main body area or covering part of the first main body area, the possibility of the first hollow foil area contacting and short-circuiting with the second electrode after being folded can be further reduced.

[0013] In some embodiments, the first empty foil region is located at a first corner of the first pole piece.

[0014] In the above technical solution, by locating the first hollow foil area at the first corner of the first electrode sheet, the preparation of the first hollow foil area can be facilitated. Compared with the prior art, the ceramic coating is suitable for battery cells with multiple tabs located on the same side. The coating direction of the ceramic layer is consistent with the coating direction of the electrode sheet. Therefore, when the first hollow foil area is located at the first corner of the first electrode sheet, conventional coating methods cannot meet the requirements. In some embodiments of the present application, the thickness of the insulating adhesive layer is H1, and the thickness of the first active material layer is H2, satisfying 1 / 5≤H1 / H2≤1.

[0015] In the above technical solution, when the ratio H1 / H2 of the thickness H1 of the insulating adhesive layer to the thickness H2 of the first active material layer is greater than or equal to 1 / 5, the thickness of the insulating adhesive layer can be made larger, the insulation effect between the first empty foil area and the second electrode piece is better, the insulation reliability is higher, and the possibility of short circuit between the first empty foil area and the second electrode piece can be reduced, thereby reducing the possibility of thermal runaway of the battery cell; when the ratio H1 / H2 of the thickness H1 of the insulating adhesive layer to the thickness H2 of the first active material layer is less than or equal to 1, the insulating adhesive layer can not exceed the first active material layer in the thickness direction, thereby making it possible to set the insulating adhesive layer. It will not increase the thickness of the electrode assembly, which is beneficial to improving the energy density of the battery cell; therefore, when the ratio H1 / H2 of the thickness H1 of the insulating glue layer to the thickness H2 of the first active material layer is 1 / 5-1, the insulating glue layer can have a better insulation effect on the first empty foil area and the second electrode piece, and the insulation reliability is higher, which can reduce the possibility of short circuit between the first empty foil area and the second electrode piece, thereby reducing the possibility of thermal runaway of the battery cell; and the insulating glue layer can not exceed the first active material layer in the thickness direction, so that the setting of the insulating glue layer will not increase the thickness of the electrode assembly, which is beneficial to improving the energy density of the battery cell.

[0016] In some embodiments of the present application, the thickness of the insulating adhesive layer is H1, which satisfies 10 μm≤H1≤100 μm.

[0017] In the above technical solution, when the thickness H1 of the insulating adhesive layer is greater than or equal to 10 μm, the thickness of the insulating adhesive layer can be made larger, the insulation effect between the first empty foil area and the second electrode piece is better, the insulation reliability is higher, and the possibility of short circuit between the first empty foil area and the second electrode piece can be reduced, thereby reducing the possibility of thermal runaway of the battery cell; when the thickness H1 of the insulating adhesive layer is less than or equal to 100 μm, the insulating adhesive layer can not exceed the first active material layer in the thickness direction or the thickness exceeding the first active material layer is smaller, thereby making the setting of the insulating adhesive layer have a smaller effect on the thickness of the electrode assembly. Small, which is beneficial to improving the energy density of the battery cell; therefore, when the thickness H1 of the insulating glue layer is 10μm-100μm, the insulating glue layer can have a better insulation effect on the first empty foil area and the second electrode piece, and the insulation reliability is higher, which can reduce the possibility of short circuit between the first empty foil area and the second electrode piece, thereby reducing the possibility of thermal runaway of the battery cell; and the insulating glue layer can not exceed the first active material layer in the thickness direction or the thickness exceeding the first active material layer is smaller, so that the setting of the insulating glue layer has less effect on the thickness of the electrode assembly, which is beneficial to improving the energy density of the battery cell.

[0018] In some embodiments of the present application, 20 μm≤H1≤60 μm.

[0019] In the above technical solution, when the thickness H1 of the insulating adhesive layer is greater than or equal to 20 μm, the thickness of the insulating adhesive layer can be further increased, the insulation effect between the first empty foil area and the second electrode piece is better, the insulation reliability is higher, and the possibility of short circuit between the first empty foil area and the second electrode piece is further reduced, thereby further reducing the possibility of thermal runaway of the battery cell; when the thickness H1 of the insulating adhesive layer is less than or equal to 60 μm, the insulating adhesive layer can be further made not to exceed the first active material layer in the thickness direction or the thickness exceeding the first active material layer is smaller, thereby further making the thickness of the electrode assembly provided with the insulating adhesive layer less affected, and having It is beneficial to further improve the energy density of the battery cell; therefore, when the thickness H1 of the insulating rubber layer is 20μm-60μm, it can further make the insulating rubber layer have a better insulation effect on the first empty foil area and the second electrode piece, and the insulation reliability is higher, which can further reduce the possibility of short circuit between the first empty foil area and the second electrode piece, thereby further reducing the possibility of thermal runaway of the battery cell; it can also further ensure that the insulating rubber layer does not exceed the first active material layer in the thickness direction or the thickness exceeding the first active material layer is smaller, thereby further reducing the influence of the thickness of the insulating rubber layer electrode assembly, which is beneficial to further improve the energy density of the battery cell.

[0020] In some embodiments of the present application, the width of the insulating adhesive layer is W1, and the width of the portion of the second electrode extending beyond the boundary between the first hollow foil area and the first main body area is W2, satisfying W1>W2.

[0021] In the above technical solution, by making the width W1 of the insulating adhesive layer and the width W2 of the part of the second electrode that exceeds the boundary of the first hollow foil area and the first main area satisfy W1>W2, it is possible to make part of the insulating adhesive layer located between the first hollow foil area and the adjacent second electrode along the first direction, and make the projection of the second electrode fall within the projection of the insulating adhesive layer in the width direction of the insulating adhesive layer after the first hollow foil area is folded, thereby playing an insulating role between the first hollow foil area and the second electrode, reducing the possibility of short circuit between the first hollow foil area and the second electrode, and thus reducing the possibility of thermal runaway of the battery cell.

[0022] In some embodiments of the present application, the width of the insulating adhesive layer is W1, satisfying 2mm≤W1≤6mm.

[0023] In the above technical solution, when the width W1 of the insulating adhesive layer is greater than or equal to 2 mm, the insulating adhesive layer can be located between the first empty foil area and the adjacent second electrode piece after the first empty foil area is folded, thereby playing an insulating role between the first empty foil area and the second electrode piece, reducing the possibility of short circuit between the first empty foil area and the second electrode piece, thereby reducing the possibility of thermal runaway of the battery cell; when the width W1 of the insulating adhesive layer is less than or equal to 6 mm, the area covered by the insulating adhesive layer on the first empty foil area is smaller, which facilitates the connection of multiple first empty foil areas and reduces the length of the first empty foil area. It is beneficial to improve the energy density of the battery cell; therefore, when the width W1 of the insulating rubber layer is 2mm-6mm, the insulating rubber layer can be located between the first empty foil area and the adjacent second electrode piece after the first empty foil area is folded, thereby playing an insulating role between the first empty foil area and the second electrode piece, reducing the possibility of short circuit between the first empty foil area and the second electrode piece, thereby reducing the possibility of thermal runaway of the battery cell, and making the area of ​​the first empty foil area covered by the insulating rubber layer smaller, facilitating the connection of multiple first empty foil areas and reducing the length of the first empty foil area, which is beneficial to improving the energy density of the battery cell.

[0024] In some embodiments of the present application, the insulating adhesive layer is made of at least one material selected from epoxy resin, polyurethane, polyethylene, polypropylene, and polyolefin.

[0025] In the above technical solution, by making the insulating adhesive layer from at least one material selected from epoxy resin, polyurethane, polyethylene, polypropylene, and polyolefin, the insulating adhesive layer can provide better insulation between the first empty foil area and the second pole piece, and the insulation reliability is higher.

[0026] In some embodiments of the present application, the boundary between the first hollow foil area and the first main body area is in the shape of a straight line, an arc line, or a broken line.

[0027] In the above technical solution, the boundary between the first hollow foil area and the first main body area is straight, arc-shaped or broken line-shaped, which can be applied to different types of battery cells, and the operation of attaching the insulating adhesive layer to the straight, arc-shaped or broken line-shaped boundary is simple, so that the preparation difficulty and cost of the insulating adhesive layer are relatively low.

[0028] In some embodiments of the present application, the second electrode sheet includes a second current collector and a second active material layer, the second current collector includes a second main body area and a second empty foil area, the second empty foil area is located at the second corner of the second electrode sheet, the surface of the second main body area is provided with a second active material layer, and the surface of the second empty foil area is not provided with a second active material layer, and the second empty foil areas of multiple second electrode sheets are stacked along the first direction; the first electrode sheet has a second notch, and when observed along the first direction, the first notch and the second notch do not overlap, and the second empty foil area at least partially overlaps with the second notch.

[0029] In the above technical solution, the second electrode sheet includes a second current collector and a second active material layer, the second current collector includes a second main area and a second empty foil area, the second main area is provided with a second active material layer, and the surface of the second empty foil area is not provided with a second active material layer, and the second empty foil areas of the plurality of second electrode sheets are stacked along the first direction; the first electrode sheet has a second notch, and when viewed along the first direction, the first notch and the second notch do not overlap, and the second empty foil area at least partially overlaps with the second notch, which can reduce the volume of the second empty foil area protruding from the second electrode sheet, and the space reserved between the electrode assembly and the battery cell shell for accommodating the second empty foil area is small, which can improve the energy density of the battery cell, and 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 second empty foil area is less likely to short-circuit with the first electrode sheet, thereby reducing the risk of thermal runaway of the battery cell; by locating the second empty foil area at the second corner position of the second electrode sheet, the preparation of the second empty foil area can be facilitated.

[0030] In some embodiments of the present application, the electrode assembly further includes a diaphragm, which is disposed between the first electrode plate and the second electrode plate. The diaphragm has a third notch and a fourth notch. When viewed along the first direction, the first empty foil area at least partially overlaps with the third notch, and the second empty foil area at least partially overlaps with the fourth notch.

[0031] In the above technical solution, the electrode assembly also includes a diaphragm, which is arranged between the first electrode piece and the second electrode piece. The diaphragm has a third notch and a fourth notch. When viewed along the first direction, the first empty foil area at least partially overlaps with the third notch, and the second empty foil area at least partially overlaps with the fourth notch, so that the third notch can be used to accommodate the first empty foil area, and the fourth notch can be used to accommodate the second empty foil area, which can facilitate the separate connection of multiple first empty foil areas and multiple second empty foil areas.

[0032] In some embodiments of the present application, the first electrode is a positive electrode, and the second electrode is a negative electrode.

[0033] In the above technical solution, since the size of the negative electrode sheet is larger than that of the positive electrode sheet in the battery cell, and the first empty foil area is provided on the side of the positive electrode sheet, the projection of the negative electrode sheet along the first direction exceeds the positive electrode sheet. Therefore, the first empty foil area may contact the puncture point on the end face of the negative electrode sheet that pierces the diaphragm after being folded. By providing an insulating rubber layer, the possibility of short circuit between the first empty foil area and the negative electrode sheet can be reduced, thereby reducing the risk of thermal runaway of the battery cell; and the second empty foil area of ​​the negative electrode sheet is less likely to contact the positive electrode sheet after being folded.

[0034] In a second aspect, the present application provides a method for preparing a battery cell, comprising:

[0035] Prepare a plurality of first electrode sheets so that the first current collector of the first electrode sheet forms a first main body region and a first hollow foil region, the first main body region is provided with a first active material layer on a surface, and the first hollow foil region is not provided with the first active material layer on a surface;

[0036] Insulating the adhesive layer in the first hollow foil area so that the insulating adhesive layer is connected to the first main body area;

[0037] Prepare a plurality of second pole pieces, so that the second pole pieces are formed with first notches, and the polarities of the first pole piece and the second pole piece are opposite;

[0038] The plurality of first pole pieces and the plurality of second pole pieces are alternately stacked, and when viewed along the first direction, at least a portion of the first empty foil area overlaps with the first notch.

[0039] In a third aspect, the present application provides an electrical device, comprising a battery cell as described above, the battery cell being used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] 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.

[0041] FIG1 is a schematic cross-sectional view of a battery cell according to some embodiments of the present application;

[0042] FIG2 is a schematic structural diagram of a first electrode piece of a battery cell provided in some embodiments of the present application;

[0043] FIG3 is a schematic structural diagram of a first current collector of a battery cell provided in some embodiments of the present application;

[0044] FIG4 is a schematic structural diagram of a second pole piece of a battery cell provided in some embodiments of the present application;

[0045] FIG5 is a schematic structural diagram of a second current collector of a battery cell provided in some embodiments of the present application;

[0046] FIG6 is a schematic structural diagram of a first electrode piece of a battery cell provided in some other embodiments of the present application;

[0047] FIG7 is a schematic structural diagram of a first electrode piece of a battery cell provided in some other embodiments of the present application;

[0048] FIG8 is a schematic structural diagram of a first electrode piece of a battery cell provided in some other embodiments of the present application;

[0049] FIG9 is a schematic structural diagram of a first electrode piece of a battery cell provided in some other embodiments of the present application;

[0050] FIG10 is a schematic structural diagram of a first electrode piece of a battery cell provided in some other embodiments of the present application;

[0051] FIG11 is a schematic diagram of the structure of a diaphragm of a battery cell provided in some embodiments of the present application;

[0052] FIG12 is a schematic flow chart of a method for preparing a battery cell according to some embodiments of the present application.

[0053] Icon: 10-battery cell; 100-electrode assembly; 110-first pole piece; 111-first current collector; 1111-first main body area; 1112-first hollow foil area; 112-first active material layer; 113-second notch; 120-second pole piece; 121-first notch; 122-second current collector; 1221-second main body area; 1222-second hollow foil area; 123-second active material layer; 130-insulating adhesive layer; 140-diaphragm; X-first direction; Y-second direction; Z-third direction.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] With the development of the new energy industry, batteries are gradually developing in the direction of high energy density and high power density, and the safety requirements for batteries are also getting higher and higher. The electrode assembly includes two pole pieces with different polarities (such as a positive pole piece and a negative pole piece), and each pole piece is connected to a pole ear. Due to the different sizes of the two pole pieces, in the thickness direction of the electrode assembly, the projection of the pole ear connected to the smaller pole piece (such as the positive pole piece) overlaps with the projection of the larger pole piece (such as the negative pole piece), which may cause the end face burrs of the smaller pole piece to short-circuit with the larger pole piece, causing thermal runaway of the battery cell. Insulation between the pole ear and the pole piece can be achieved by providing an insulating layer on the edge of the pole ear. At present, the insulating layer is generally made of ceramic material, which needs to be stirred by a stirring tank and needs to be coated by a coating device. The preparation and coating processes are relatively complicated, resulting in high difficulty and cost in the preparation of the battery. Furthermore, the coating device for ceramic materials can generally only achieve coating in a single direction along the transmission direction of the electrode assembly. Therefore, it is only applicable to batteries in which the tabs are arranged parallel to the transmission direction of the electrode assembly, resulting in a relatively small scope of application.

[0060] In order to reduce the difficulty and cost of preparing a battery cell, the present application provides a battery cell, which includes an electrode assembly, the electrode assembly is a laminated structure, the electrode assembly includes a plurality of first electrode sheets and a plurality of second electrode sheets stacked along a first direction, and the first electrode sheets have opposite polarity to the second electrode sheets; the first electrode sheet includes a first current collector and a first active material layer, the first current collector includes a first main body area and a first empty foil area, the surface of the first main body area is provided with the first active material layer, and the surface of the first empty foil area is not provided with the first active material layer, and the first empty foil areas of the plurality of first electrode sheets are stacked along the first direction; the second electrode sheet has a first notch, and when viewed along the first direction, at least part of the first empty foil area overlaps with the first notch; an insulating adhesive layer is provided on the first empty foil area, and the insulating adhesive layer is connected to the first main body area.

[0061] In a battery cell of this structure, the battery cell includes an electrode assembly, the electrode assembly is a laminated structure, the electrode assembly includes a plurality of first pole pieces and a plurality of second pole pieces stacked along a first direction, the first pole piece and the second pole piece have opposite polarity; the first pole piece includes a first current collector and a first active material layer, the first current collector includes a first main body area and a first empty foil area, the surface of the first main body area is provided with a first active material layer, and the surface of the first empty foil area is not provided with the first active material layer, the first empty foil areas of the plurality of first pole pieces are stacked along the first direction, so that the electrode assembly can be electrically connected to the load through the plurality of first empty foil areas; the second pole piece has a first notch, and when viewed along the first direction, at least part of the first empty foil area overlaps with the first notch, which can reduce the volume of the first empty foil area protruding from the first pole piece, and the space reserved between the electrode assembly and the battery cell shell for accommodating the first empty foil area is small, which can The energy density of the battery cell can be improved, and when the battery cell is subjected to external force or falls, the electrode assembly is less likely to shake relative to the casing, and the possibility of the first hollow foil area and the second electrode piece contacting and short-circuiting is also smaller, thereby reducing the risk of thermal runaway of the battery cell; an insulating adhesive layer is provided on the first hollow foil area, and the insulating adhesive layer is connected to the first main area, which can play an insulating role between the first hollow foil area and the second electrode piece, reducing the possibility of the burrs on the end surface of the second electrode piece extending beyond the first main area contacting and short-circuiting with the first hollow foil area, and for a battery cell structure with multiple first hollow foil areas connected together, the insulating adhesive layer can reduce the possibility of the first hollow foil area contacting and short-circuiting with the second electrode piece after being collapsed, thereby reducing the possibility of thermal runaway of the battery cell, and at the same time, the preparation difficulty and cost of the insulating adhesive layer are relatively low, the operation of attaching it to the first electrode piece is also relatively simple, and the insulating adhesive layer can be attached along different shapes, and has a wide range of applications.

[0062] The battery cells provided in the embodiments of the present application can be secondary batteries or primary batteries, such as lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, and are not limited to this embodiment of the present application. The battery cells can be cylindrical, flat, rectangular, or in other shapes, and are not limited to this embodiment of the present application.

[0063] 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.

[0064] Referring to Figures 1 to 5, Figure 1 is a schematic diagram of the cross-sectional structure of the battery cell provided in some embodiments of the present application, Figure 2 is a schematic diagram of the structure of the first electrode piece of the battery cell provided in some embodiments of the present application, Figure 3 is a schematic diagram of the structure of the first current collector of the battery cell provided in some embodiments of the present application, Figure 4 is a schematic diagram of the structure of the second 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 current collector of the battery cell provided in some embodiments of the present application.

[0065] The present embodiment provides a battery cell 10, comprising an electrode assembly 100. The electrode assembly 100 has a laminated structure and includes a plurality of first electrode sheets 110 and a plurality of second electrode sheets 120 stacked along a first direction. The first electrode sheets 110 and the second electrode sheets 120 have opposite polarities. The first electrode sheet 110 includes a first current collector 111 and a first active material layer 112. The first current collector 111 includes a first main body region 1111 and a first hollow foil region 1112. The first main body region 1111 is provided with the first active material layer 112, while the first hollow foil region 1112 is not provided with the first active material layer 112. The first hollow foil regions 1112 of the plurality of first electrode sheets 110 are stacked along the first direction. The second electrode sheets 120 have a first notch 121. When viewed along the first direction, at least a portion of the first hollow foil region 1112 overlaps with the first notch 121. An insulating adhesive layer 130 is disposed on the first hollow foil area 1112 , and the insulating adhesive layer 130 is connected to the first main body area 1111 .

[0066] The electrode assembly 100 has a laminated structure and includes a plurality of first electrode sheets 110 and a plurality of second electrode sheets 120 stacked along a first direction. The first electrode sheets 110 and the second electrode sheets 120 have opposite polarities. The first electrode sheet 110 includes a first current collector 111 and a first active material layer 112. The first current collector 111 includes a first main body region 1111 and a first hollow foil region 1112. The first main body region 1111 is provided with the first active material layer 112, while the first hollow foil region 1112 is not provided with the first active material layer 112. The first hollow foil regions 1112 of the plurality of first electrode sheets 110 are stacked along the first direction, enabling the electrode assembly 100 to achieve electrical connection to a load through the plurality of first hollow foil regions 1112. The second electrode sheet 120 has a first notch 121. When viewed along the first direction, at least a portion of the first empty foil area 1112 overlaps with the first notch 121, thereby reducing the volume of the first empty foil area 1112 protruding from the first electrode sheet 110. The space reserved between the electrode assembly 100 and the outer casing of the battery cell 10 for accommodating the first empty foil area 1112 is relatively small, which 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 outer casing, and the first empty foil area 1112 is less likely to contact and short-circuit with the second electrode sheet 120, thereby reducing the risk of thermal runaway of the battery cell 10. An insulating adhesive layer 130 is provided on the first hollow foil area 1112. The insulating adhesive layer 130 is connected to the first main body area 1111 and can play an insulating role between the first hollow foil area 1112 and the second electrode 120, thereby reducing the possibility of burrs on the end surface of the second electrode 120 extending beyond the first main body area 1111 contacting and short-circuiting with the first hollow foil area 1112. Moreover, for a battery cell structure in which multiple first hollow foil areas 1112 are gathered and connected, the insulating adhesive layer 130 can reduce the possibility of the first hollow foil area 1112 contacting and short-circuiting with the second electrode 120 after being gathered, thereby reducing the possibility of thermal runaway of the battery cell 10. At the same time, the preparation difficulty and cost of the insulating adhesive layer 130 are relatively low, and the operation of attaching it to the first electrode 110 is also relatively simple. Moreover, the insulating adhesive layer 130 can be attached along different shapes, and has a wide range of applications.

[0067] In some embodiments, the insulating adhesive layer 130 is adjacent to the first main body region 1111 or covers a portion of the first main body region 1111 .

[0068] By making the insulating adhesive layer 130 adjacent to the first main body area 1111 or covering a portion of the first main body area 1111 , the possibility of short circuiting caused by contact between the first hollow foil area 1112 and the second electrode 120 after being folded can be further reduced.

[0069] In some embodiments, the first empty foil region 1112 is located at a first corner of the first pole piece 110 .

[0070] 6-10 , the first electrode piece 110 is rectangular. No active material is provided at one corner of the first electrode piece 110 , or the active material is cleaned away to form a first empty foil area 1112 . The first empty foil area 1112 extends to the edges of the first electrode piece 110 in the second direction Y and the third direction Z.

[0071] By locating the first empty foil area 1112 at the first corner of the first electrode piece 110, the preparation of the first empty foil area 1112 can be facilitated. Compared with the existing technology, ceramic coating is suitable for battery cells with multiple tabs on the same side. The coating direction of the ceramic layer is consistent with the coating direction of the electrode piece. Therefore, when the first empty foil area 1112 is located at the first corner of the first electrode piece 110, conventional coating methods cannot meet the requirements.

[0072] In other embodiments, the first empty foil area 1112 may also be the middle of the first pole piece 110 along the third direction Z, or the middle of the first pole piece 110 along the second direction Y.

[0073] In some embodiments, the thickness of the insulating adhesive layer 130 is H1, and the thickness of the first active material layer 112 is H2, satisfying 1 / 5≤H1 / H2≤1. For example, H1 / H2 can be 1 / 5, 1 / 2, or 1.

[0074] When the ratio H1 / H2 of the thickness H1 of the insulating adhesive layer 130 to the thickness H2 of the first active material layer 112 is greater than or equal to 1 / 5, the thickness of the insulating adhesive layer 130 can be made larger, the insulation effect between the first empty foil area 1112 and the second electrode 120 is better, the insulation reliability is higher, and the possibility of short circuit between the first empty foil area 1112 and the second electrode 120 is reduced, thereby reducing the possibility of thermal runaway of the battery cell 10; when the ratio H1 / H2 of the thickness H1 of the insulating adhesive layer 130 to the thickness H2 of the first active material layer 112 is less than or equal to 1, the insulating adhesive layer 130 does not exceed the first active material layer 112 in the thickness direction, so that the provision of the insulating adhesive layer 130 does not increase the electrode The thickness of the assembly 100 is beneficial to improving the energy density of the battery cell 10; therefore, when the ratio H1 / H2 of the thickness H1 of the insulating adhesive layer 130 to the thickness H2 of the first active material layer 112 is 1 / 5-1, the insulating adhesive layer 130 can have a better insulation effect on the first empty foil area 1112 and the second electrode piece 120, and the insulation reliability is higher, which can reduce the possibility of short circuit between the first empty foil area 1112 and the second electrode piece 120, thereby reducing the possibility of thermal runaway of the battery cell 10; and the insulating adhesive layer 130 can not exceed the first active material layer 112 in the thickness direction, so that the setting of the insulating adhesive layer 130 will not increase the thickness of the electrode assembly 100, which is beneficial to improving the energy density of the battery cell 10.

[0075] In some embodiments, the thickness of the insulating adhesive layer 130 is H1, which satisfies 10 μm≤H1≤100 μm. For example, H1 can be 10 μm, 50 μm, or 100 μm.

[0076] When the thickness H1 of the insulating adhesive layer 130 is greater than or equal to 10 μm, the thickness of the insulating adhesive layer 130 can be larger, the insulation effect between the first empty foil area 1112 and the second electrode 120 is better, the insulation reliability is higher, and the possibility of short circuit between the first empty foil area 1112 and the second electrode 120 is reduced, thereby reducing the possibility of thermal runaway of the battery cell 10; when the thickness H1 of the insulating adhesive layer 130 is less than or equal to 100 μm, the insulating adhesive layer 130 does not exceed the first active material layer 112 in the thickness direction or the thickness exceeding the first active material layer 112 is smaller, thereby making the setting of the insulating adhesive layer 130 have less effect on the thickness of the electrode assembly 100, which is beneficial to the Improve the energy density of the battery cell 10; therefore, when the thickness H1 of the insulating glue layer 130 is 10μm-100μm, the insulating glue layer 130 can have a better insulation effect on the first empty foil area 1112 and the second electrode piece 120, and the insulation reliability is higher, which can reduce the possibility of short circuit between the first empty foil area 1112 and the second electrode piece 120, thereby reducing the possibility of thermal runaway of the battery cell 10; and the insulating glue layer 130 does not exceed the first active material layer 112 in the thickness direction or the thickness exceeding the first active material layer 112 is smaller, so that the setting of the insulating glue layer 130 has less effect on the thickness of the electrode assembly 100, which is beneficial to improve the energy density of the battery cell 10.

[0077] In some embodiments, 20 μm ≤ H1 ≤ 60 μm. For example, H1 may be 20 μm, 40 μm, or 60 μm.

[0078] When the thickness H1 of the insulating adhesive layer 130 is greater than or equal to 20 μm, the thickness of the insulating adhesive layer 130 can be further increased, the insulation effect between the first empty foil area 1112 and the second electrode 120 is better, the insulation reliability is higher, and the possibility of short circuit between the first empty foil area 1112 and the second electrode 120 is further reduced, thereby further reducing the possibility of thermal runaway of the battery cell 10; when the thickness H1 of the insulating adhesive layer 130 is less than or equal to 60 μm, the insulating adhesive layer 130 can be further made not to exceed the first active material layer 112 in the thickness direction or the thickness exceeding the first active material layer 112 is smaller, thereby further making the thickness of the electrode assembly 100 less affected by the setting of the insulating adhesive layer 130, which is beneficial to further Improve the energy density of the battery cell 10; therefore, when the thickness H1 of the insulating glue layer 130 is 20μm-60μm, it can further make the insulating glue layer 130 have a better insulation effect on the first empty foil area 1112 and the second electrode piece 120, and the insulation reliability is higher, which can further reduce the possibility of short circuit between the first empty foil area 1112 and the second electrode piece 120, thereby further reducing the possibility of thermal runaway of the battery cell 10; it can also further make the insulating glue layer 130 not exceed the first active material layer 112 in the thickness direction or the thickness exceeding the first active material layer 112 is smaller, thereby further making the thickness of the electrode assembly 100 less affected by the setting of the insulating glue layer 130, which is beneficial to further improve the energy density of the battery cell 10.

[0079] In some embodiments, the width of the insulating adhesive layer 130 is W1, and the width of the portion of the second electrode 120 extending beyond the boundary between the first hollow foil region 1112 and the first main region 1111 is W2, satisfying W1>W2. For example, W1 is 1.1*W2, 1.15*W2, or 1.2*W2.

[0080] By ensuring that the width W1 of the insulating adhesive layer 130 and the width W2 of the portion of the second electrode piece 120 extending beyond the boundary between the first hollow foil area 1112 and the first main area 1111 satisfy W1>W2, it is possible to ensure that along the first direction X, a portion of the insulating adhesive layer 130 is located between the first hollow foil area 1112 and the adjacent second electrode piece 120, and that after the first hollow foil area 1112 is collapsed, the projection of the second electrode piece 120 falls within the projection of the insulating adhesive layer 130 in the width direction of the insulating adhesive layer, thereby providing insulation between the first hollow foil area 1112 and the second electrode piece 120, reducing the possibility of a short circuit between the first hollow foil area 1112 and the second electrode piece 120, and thereby reducing the possibility of thermal runaway of the battery cell 10.

[0081] In some embodiments, the width of the insulating adhesive layer 130 is W1, which satisfies 2 mm ≤ W1 ≤ 6 mm. For example, W1 can be 2 mm, 4 mm, or 6 mm.

[0082] When the width W1 of the insulating adhesive layer 130 is greater than or equal to 2 mm, the insulating adhesive layer 130 can be located between the first empty foil area 1112 and the adjacent second electrode piece 120 after the first empty foil area 1112 is folded, thereby playing an insulating role between the first empty foil area 1112 and the second electrode piece 120, reducing the possibility of short circuit between the first empty foil area 1112 and the second electrode piece 120, thereby reducing the possibility of thermal runaway of the battery cell 10; when the width W1 of the insulating adhesive layer 130 is less than or equal to 6 mm, the area covered by the insulating adhesive layer 130 on the first empty foil area 1112 is small, which facilitates the connection of multiple first empty foil areas 1112 and reduces the length of the first empty foil area 1112, which is beneficial to improving the battery life. The energy density of the core 10; therefore, when the width W1 of the insulating glue layer 130 is 2mm-6mm, the insulating glue layer 130 can be located between the first empty foil area 1112 and the adjacent second electrode piece 120 after the first empty foil area 1112 is folded, thereby playing an insulating role between the first empty foil area 1112 and the second electrode piece 120, reducing the possibility of short circuit between the first empty foil area 1112 and the second electrode piece 120, thereby reducing the possibility of thermal runaway of the battery cell 10, and the area covered by the insulating glue layer 130 on the first empty foil area 1112 is smaller, which facilitates the connection of multiple first empty foil areas 1112 and reduces the length of the first empty foil area 1112, which is beneficial to improving the energy density of the battery cell 10.

[0083] In some embodiments, the insulating adhesive layer 130 is made of at least one of epoxy resin, polyurethane, polyethylene, polypropylene, and polyolefin.

[0084] By making the insulating adhesive layer 130 of at least one material selected from epoxy resin, polyurethane, polyethylene, polypropylene, and polyolefin, the insulating adhesive layer 130 can provide better insulation between the first empty foil area 1112 and the second electrode 120 and have higher insulation reliability.

[0085] In some embodiments, the hardness of the insulating adhesive layer 130 is 30HRC-40HRC, for example, the hardness of the insulating adhesive layer 130 is 30HRC, 35HRC, or 40HRC.

[0086] When the hardness of the insulating adhesive layer 130 is greater than or equal to 30HRC, the insulating adhesive layer 130 is not easily deformed, thereby achieving a better insulation effect between the first empty foil area 1112 and the second pole piece 120, and having a higher insulation reliability, thereby reducing the possibility of a short circuit between the first empty foil area 1112 and the second pole piece 120, and thus reducing the possibility of thermal runaway of the battery cell 10; when the hardness of the insulating adhesive layer 130 is less than or equal to 40HRC, the loss caused by interference between the insulating adhesive layer 130 and the second pole piece 120 can be reduced. Therefore, when the hardness of the insulating adhesive layer 130 is 30HRC-40HRC, the insulating adhesive layer 130 can have a better insulation effect on the first empty foil area 1112 and the second electrode piece 120, and the insulation reliability is higher, which can reduce the possibility of short circuit between the first empty foil area 1112 and the second electrode piece 120, thereby reducing the possibility of thermal runaway of the battery cell 10, and reducing the possibility of damaging the second electrode piece 120 when the insulating adhesive layer 130 interferes with the second electrode piece 120.

[0087] 2 and 6 , FIG6 is a schematic structural diagram of the first electrode of a battery cell provided in other embodiments of the present application.

[0088] In some embodiments, the boundary between the first empty foil region 1112 and the first main body region 1111 is a straight line.

[0089] Refer to FIG. 7 , which is a schematic structural diagram of the first electrode of a battery cell provided in some other embodiments of the present application.

[0090] In other embodiments, the boundary between the first empty foil area 1112 and the first main body area 1111 may be in the shape of a broken line.

[0091] Refer to FIG8 , which is a schematic structural diagram of the first electrode of a battery cell provided in some other embodiments of the present application.

[0092] In other embodiments, the boundary between the first empty foil area 1112 and the first main body area 1111 may be in an arc shape.

[0093] The boundary between the first hollow foil area 1112 and the first main body area 1111 is in a straight line, an arc, or a zigzag shape, which is suitable for different types of battery cells 10. Furthermore, the insulating adhesive layer 130 is easily attached to the straight line, arc, or zigzag boundary, making the preparation of the insulating adhesive layer 130 both difficult and cost-effective. If existing coating methods were used, it would be difficult to adapt to the changing boundaries.

[0094] 6 , in some embodiments, the first hollow foil area 1112 extends along the third direction Z and is spaced apart from the first main area 1111 along the second direction Y. This facilitates the collapsing and connection of the first hollow foil areas 1112 of the plurality of first electrode sheets 110. The space between the first hollow foil area 1112 and the first main area 111 can reserve space for the collapsing and deformation of the first hollow foil area 1112, thereby providing the first hollow foil area 1112 with a certain degree of freedom, thereby reducing the possibility of tearing between the first hollow foil area 1112 and the first main area 1111.

[0095] Referring to Figures 2, 4, and 5, in some embodiments, the second electrode 120 includes a second current collector 122 and a second active material layer 123. The second current collector 122 includes a second main body region 1221 and a second hollow foil region 1222. The second hollow foil region 1222 is located at a second corner of the second electrode 120. The second main body region 1221 is provided with the second active material layer 123, while the second hollow foil region 1222 is not provided with the second active material layer 123. The second hollow foil regions 1222 of the plurality of second electrode sheets 120 are stacked along a first direction. The first electrode 110 has a second notch 113. When viewed along the first direction, the first notch 121 and the second notch 113 do not overlap, and the second hollow foil region 1222 at least partially overlaps with the second notch 113.

[0096] The second electrode sheet 120 includes a second current collector 122 and a second active material layer 123, the second current collector 122 includes a second main body area 1221 and a second empty foil area 1222, the second main body area 1221 is provided with the second active material layer 123, and the second empty foil area 1222 is not provided with the second active material layer 123, the second empty foil areas 1222 of the plurality of second electrode sheets 120 are stacked along the first direction; the first electrode sheet 110 has a second notch 113, and when viewed along the first direction, the first notch 121 and the second notch 113 do not overlap. The second hollow foil area 1222 at least partially overlaps with the second notch 113, which can reduce the volume of the second hollow foil area 1222 protruding from the second electrode sheet 120. The space reserved between the electrode assembly 100 and the outer casing of the battery cell 10 for accommodating the second hollow foil area 1222 is smaller, which can improve the energy density of the battery cell 10. When the battery cell 10 is subjected to external force or dropped, the electrode assembly 100 is less likely to shake relative to the outer casing, and the second hollow foil area 1222 is less likely to contact and short-circuit with the first electrode sheet 110, thereby reducing the risk of thermal runaway in the battery cell 10. By locating the second hollow foil area 1222 at the second corner of the second electrode sheet 120, the preparation of the second hollow foil area 1222 can be facilitated.

[0097] 2 , 7 and 8 , in some embodiments, the edge of the second notch 113 is arranged in a straight line, which facilitates the preparation and formation of the second notch 113 and is applicable to the second empty foil area 1222 with a straight line boundary.

[0098] 6 and 9 , FIG9 is a schematic diagram of the structure of the first electrode of the battery cell provided in some other embodiments of the present application. In some embodiments, the edge of the second notch 113 is arranged in a zigzag shape, which can be suitable for the second empty foil area 1222 with a zigzag boundary.

[0099] 2 , 9 and 10 , in some embodiments, the edge of the first empty foil area 1112 has the same shape as the edge of the second notch 113 , so that the shape of the first empty foil area 1112 can be the same as the shape of the second empty foil area 1222 , so that the preparation and connection methods of the first empty foil area 1112 and the second empty foil area 1222 are similar, thereby facilitating the preparation of the battery cell 10 .

[0100] 10 is a schematic diagram of the structure of the first electrode of the battery cell provided in some other embodiments of the present application. In some embodiments, the edge of the second notch 113 is arranged in an arc shape, which can be suitable for the second empty foil area 1222 with an arc-shaped boundary.

[0101] In some embodiments, the first notch 121 and the first empty foil area 1112 are located at one end of the first electrode 110 along the second direction Y, and the first notch 121 and the first empty foil area 1112 are spaced apart along the third direction Z. The second direction Y is parallel to the length direction of the first electrode, and the third direction Z is parallel to the width direction of the first electrode.

[0102] By locating the first notch 121 and the first empty foil area 1112 at one end of the first electrode sheet 110 along the second direction Y, the first empty foil area 1112 and the second empty foil area 1222 can be led out from the end of the battery cell 10 along the second direction Y, thereby facilitating electrical connection of the battery cell 10 to a load via the first empty foil area 1112 and the second empty foil area 1222. By arranging the first notch 121 and the first empty foil area 1112 at intervals along the third direction Z, the possibility of short circuits between the first empty foil area 1112 and the second electrode sheet 120, and between the second empty foil area 1222 and the first electrode sheet 110, can be reduced.

[0103] In some embodiments, the second notch 131 and the second empty foil area 1222 are located at one end of the second electrode 120 along the second direction Y, and the second notch 131 and the second empty foil area 1222 are spaced apart along the third direction Z.

[0104] By locating the second notch 131 and the second empty foil area 1222 at one end of the second electrode sheet 120 along the second direction Y, the first empty foil area 1112 and the second empty foil area 1222 can be led out from the end of the battery cell 10 along the second direction Y, thereby facilitating electrical connection of the battery cell 10 to a load via the first empty foil area 1112 and the second empty foil area 1222. By arranging the second notch 131 and the second empty foil area 1222 at intervals along the third direction Z, the possibility of short circuiting between the first empty foil area 1112 and the second electrode sheet 120, and between the second empty foil area 1222 and the first electrode sheet 110, can be reduced.

[0105] 6 to 10 , in some embodiments, along the second direction Y, the first empty foil area 1112 does not extend beyond the first active material layer 112 ; along the third direction Z, the first empty foil area 1112 does not extend beyond the first active material layer 112 .

[0106] Along the second direction Y, the first empty foil area 1112 does not exceed the first active material layer 112; along the third direction Z, the first empty foil area 1112 does not exceed the first active material layer 112, so that the first empty foil area 1112 does not protrude from the first electrode sheet 110, and there is no need to reserve an accommodation space for the first empty foil area 1112 between the electrode assembly 100 and the outer shell (not shown in the figure), which can further improve the energy density of the battery cell 10, and when the battery cell 10 is subjected to external force or falls, the possibility of the electrode assembly 100 shaking relative to the outer shell is further reduced, and the possibility of the first empty foil area 1112 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.

[0107] In some embodiments, the edge of the first empty foil area 1112 is flush with the edge of the first active material layer 112 along the second direction Y, and the edge of the first empty foil area 1112 is flush with the edge of the first active material layer 112 along the third direction Z. This facilitates the preparation of the first empty foil area 1112.

[0108] 1 and 11 , FIG11 is a schematic structural diagram of a diaphragm of a battery cell provided in some embodiments of the present application.

[0109] In some embodiments, the electrode assembly 100 further includes a diaphragm 140, which is disposed between the first electrode piece 110 and the second electrode piece 120. The diaphragm 140 has a third notch 141 and a fourth notch 142. When viewed along the first direction, the first empty foil area 1112 at least partially overlaps with the third notch 141, and the second empty foil area 1222 at least partially overlaps with the fourth notch 142.

[0110] By disposing the diaphragm 140 between the first electrode piece 110 and the second electrode piece 120, the diaphragm 140 has a third notch 141 and a fourth notch 142. When viewed along the first direction, the first empty foil area 1112 at least partially overlaps with the third notch 141, and the second empty foil area 1222 at least partially overlaps with the fourth notch 142, so that the third notch 141 can be used to accommodate the first empty foil area 1112, and the fourth notch 142 can be used to accommodate the second empty foil area 1222, which can facilitate the separate connection of multiple first empty foil areas 1112 and multiple second empty foil areas 1222.

[0111] In some embodiments, the third notch 141 has the same or similar shape as the first empty foil area 1112, and the fourth notch 142 has the same or similar shape as the second empty foil area 1222, so that the diaphragm 140 can have a better isolation effect on the first electrode 110 and the second electrode 120, and can reduce the obstruction of the diaphragm 140 to the first empty foil area 1112 or the second empty foil area 1222 when it is collapsed.

[0112] In some embodiments, the first electrode 110 is a positive electrode, and the second electrode 120 is a negative electrode.

[0113] Since in the battery cell 10, the size of the negative electrode sheet is larger than that of the positive electrode sheet, and the projection of the negative electrode sheet along the first direction exceeds the positive electrode sheet on the side where the first empty foil area 1112 is provided. Therefore, the first empty foil area 1112 may contact the puncture point on the end face of the negative electrode sheet that pierces the diaphragm 140 after being folded. By providing the insulating rubber layer 130, the possibility of short circuit between the first empty foil area 1112 and the negative electrode sheet can be reduced, thereby reducing the risk of thermal runaway of the battery cell 10; and the second empty foil area 1222 of the negative electrode sheet is less likely to contact the positive electrode sheet after being folded.

[0114] 1 , in some embodiments, the battery cell 10 further includes a shell, which is used to accommodate the electrode assembly 100 and the electrolyte, so that the shell can protect the electrode assembly 100 .

[0115] In some embodiments, the battery cell 10 is a soft-pack battery cell, and the outer shell can be made of an aluminum-plastic film.

[0116] In other embodiments, the battery cell 10 may also be a hard shell battery cell, and the shell may be made of a relatively high-strength material, such as metal materials such as steel and aluminum alloy, or relatively high-strength non-metallic materials such as carbon fiber and hard plastic, so that the shell has a relatively high force-bearing performance, thereby making the shell less likely to be deformed or damaged due to force or environmental changes, thereby making the battery cell 10 more reliable.

[0117] The electrode assembly 100 consists of a positive electrode sheet, a negative electrode sheet, and a separator. The battery cell 10 primarily operates by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive electrode collector. The portion of the positive electrode collector not coated with the positive active material layer serves as the positive electrode tab, allowing electrical energy to be input or output from the positive electrode sheet through the positive electrode tab. Taking a lithium-ion battery as an example, the positive electrode current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, a ternary material, or lithium manganese oxide. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative electrode collector. The portion of the negative electrode collector not coated with the negative active material layer serves as the negative electrode tab, allowing electrical energy to 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 active material can be made of carbon or silicon. The material of the isolation film may be polypropylene (PP) or polyethylene (PE), etc. The electrolyte may include an organic solvent, an electrolyte lithium salt, etc.

[0118] In some embodiments, the battery cell 10 may further include a first electrical connector (not shown in the figure) and a second electrical connector (not shown in the figure), the first electrical connector is connected to the first empty foil area 1112, and the second electrical connector is connected to the second empty foil area 1222, and the first electrical connector and the second electrical connector extend out of the outer casing to be connected to the load.

[0119] In some embodiments, along the first direction X, the first empty foil areas 1112 of the plurality of first pole pieces 110 are gathered and connected.

[0120] By folding and connecting the first empty foil areas 1112 of the multiple first pole pieces 110 along the first direction X, the connection method of the multiple first empty foil areas 1112 can be simpler and easier to operate, and it is convenient for the multiple first empty foil areas 1112 to be led out of the battery cell 10 through the first electrical connector to be connected to the load.

[0121] Referring to FIG. 12 , FIG. 12 is a schematic flow chart of a method for preparing a battery cell according to some embodiments of the present application.

[0122] The present invention provides a method for preparing a battery cell, comprising:

[0123] S1. Prepare multiple first pole pieces so that the first current collector of the first pole piece forms a first main area and a first hollow foil area, the surface of the first main area is provided with a first active material layer, and the surface of the first hollow foil area is not provided with the first active material layer.

[0124] In some embodiments, the first active material can be coated on the entire surface of the first current collector to form a first active material layer, and then the first active material layer on the surface of the first empty foil area is removed by laser etching or other methods to expose the first empty foil area.

[0125] In other embodiments, the surface of the first empty foil area of ​​the first current collector can be blocked by a mask or other blocking material, and then the first active material is coated on the surface of the first current collector. After the blocking material is removed, the first active material layer is formed on the surface of the first main area, and the first empty foil area is exposed.

[0126] S2. Apply an insulating adhesive layer on the first empty foil area so that the insulating adhesive layer is connected to the first main body area.

[0127] S3. Prepare a plurality of second pole pieces, so that the second pole pieces are formed with first notches, and the polarities of the first pole piece and the second pole piece are opposite.

[0128] S4. Alternately stack the plurality of first electrode sheets and the plurality of second electrode sheets so that, when viewed along the first direction, at least a portion of the first empty foil area overlaps with the first notch.

[0129] An embodiment of the present application provides an electrical device, including the battery cell 10 provided in any of the above embodiments, and the battery cell 10 is used to provide electrical energy.

[0130] The electrical device may be any of the aforementioned devices or systems using the battery cell 10 .

[0131] 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.

[0132] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those 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; The first electrode sheet includes a first current collector and a first active material layer. The first current collector includes a first main body region and a first hollow foil region. The first active material layer is provided on the surface of the first main body region, and the first hollow foil region is not provided on the surface of the first active material layer. The first hollow foil regions of the plurality of first electrode sheets are stacked along the first direction. The second pole piece has a first notch, and when viewed along the first direction, at least a portion of the first empty foil area overlaps with the first notch; An insulating adhesive layer is provided on the first hollow foil area, and the insulating adhesive layer is connected to the first main body area.

2. The battery cell according to claim 1, characterized in that The insulating adhesive layer is adjacent to the first main body area or covers a portion of the first main body area.

3. The battery cell according to claim 1, characterized in that The first empty foil area is located at a first corner of the first pole piece.

4. The battery cell according to claim 1, characterized in that The thickness of the insulating adhesive layer is H1, and the thickness of the first active material layer is H2, satisfying 1 / 5≤H1 / H2≤1.

5. The battery cell according to claim 1, characterized in that The thickness of the insulating adhesive layer is H1, which satisfies 10 μm≤H1≤100 μm.

6. The battery cell according to claim 5, characterized in that 20μm≤H1≤60μm.

7. The battery cell according to any one of claims 1 to 6, characterized in that: The width of the insulating adhesive layer is W1, and the width of the portion of the second pole piece that exceeds the boundary between the first hollow foil area and the first main body area is W2, satisfying W1>W2.

8. The battery cell according to any one of claims 1 to 6, characterized in that: The width of the insulating adhesive layer is W1, which satisfies 2mm≤W1≤6mm.

9. The battery cell according to any one of claims 1 to 6, characterized in that: The insulating adhesive layer is made of at least one material selected from epoxy resin, polyurethane, polyethylene, polypropylene and polyolefin.

10. The battery cell according to any one of claims 1 to 6, characterized in that: The boundary between the first hollow foil area and the first main body area is in the shape of a straight line, an arc line or a broken line.

11. The battery cell according to claim 1, characterized in that The second pole piece includes a second current collector and a second active material layer, the second current collector includes a second main body area and a second hollow foil area, the second hollow foil area is located at a second corner of the second pole piece, the second main body area is provided with the second active material layer on the surface, and the second hollow foil area is not provided with the second active material layer on the surface, and the second hollow foil areas of the plurality of second pole pieces are stacked along the first direction; The first pole piece has a second notch. When viewed along the first direction, the first notch and the second notch do not overlap, and the second empty foil area at least partially overlaps with the second notch.

12. The battery cell according to claim 11, characterized in that The electrode assembly also includes a diaphragm, which is arranged between the first electrode plate and the second electrode plate. The diaphragm has a third notch and a fourth notch. When viewed along the first direction, the first empty foil area at least partially overlaps with the third notch, and the second empty foil area at least partially overlaps with the fourth notch.

13. The battery cell according to claim 1, characterized in that The first pole piece is a positive pole piece, and the second pole piece is a negative pole piece.

14. A method for preparing a battery cell, characterized in that: include: Prepare a plurality of first electrode sheets so that the first current collector of the first electrode sheet forms a first main body region and a first hollow foil region, wherein the first main body region is provided with a first active material layer on a surface, and the first hollow foil region is not provided with the first active material layer on a surface; Applying an insulating adhesive layer on the first hollow foil area so that the insulating adhesive layer is connected to the first main body area; Prepare a plurality of second pole pieces, such that the second pole pieces are formed with first notches, and the polarities of the first pole pieces and the second pole pieces are opposite; A plurality of the first pole pieces and a plurality of the second pole pieces are alternately stacked, and when viewed along a first direction, at least a portion of the first empty foil area overlaps with the first notch.

15. An electrical device, characterized in that: The battery cell comprises the battery cell according to any one of claims 1 to 13, wherein the battery cell is used to provide electrical energy.

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