Electrode assembly, battery cell, battery device and electric device

Abstract

The utility model provides an electrode assembly, a battery cell, a battery device and a power utilization device. The battery monomer comprises an electrode assembly, and the electrode assembly comprises a negative plate, a separator and a positive plate which are stacked. The negative plate comprises a negative tab unit and a negative plate main body, the negative tab unit is connected to one side of the negative plate main body, and the thickness of the negative plate main body is 10-30 microns. The separator is provided with a separation section for separating the positive plate from the negative plate, the separation section is provided with first exceeding parts exceeding the positive plate on two sides in the first direction, and the first exceeding parts of the two separation sections adjacent to the positive plate are at least partially and fixedly connected. The first direction is perpendicular to the stacking direction. The first exceeding parts of the two isolation sections adjacent to the positive plate are at least partially and fixedly connected, so that the position of the positive plate can be limited, the negative plate can exceed the positive plate along the first direction, the lithium precipitation risk is reduced, dendritic crystal bypassing growth can be prevented, the short circuit risk is reduced, and the reliability of the single battery is improved.

Description

Technical Field

[0001] The present application relates to the field of batteries, and more specifically, to an electrode assembly, a battery cell, a battery device, and an electrical device. Background Art

[0002] Batteries are widely used in new energy applications, such as electric vehicles and new energy vehicles. These have become a new trend in the automotive industry. The development of battery technology requires consideration of multiple design factors, including performance parameters such as energy density, cycle life, discharge capacity, and charge / discharge rate. Furthermore, battery reliability must be considered. However, current battery reliability is relatively poor. Summary of the Invention

[0003] The purpose of the embodiments of the present application is to provide an electrode assembly, a battery cell, a battery device, and an electrical device, which are intended to improve the problem of poor reliability of batteries in related technologies.

[0004] In the first aspect, an embodiment of the present application provides a battery cell, which includes a shell and an electrode assembly, the electrode assembly being accommodated in the shell, the electrode assembly including a negative electrode sheet, a separator and a positive electrode sheet, the positive electrode sheet, the separator and the negative electrode sheet being stacked, the negative electrode sheet including a negative electrode ear unit and a negative electrode sheet body, the negative electrode ear unit being connected to one side of the negative electrode sheet body, and the thickness of the negative electrode sheet body is 10μm to 30μm; the separator has an isolation segment separating the positive electrode sheet and the negative electrode sheet, the isolation segment has a first protruding portion protruding from the positive electrode sheet on both sides of a first direction, and the first protruding portions of the two isolation segments adjacent to the positive electrode sheet are at least partially fixedly connected to cover at least a portion of the edge of the positive electrode sheet, and the first direction is perpendicular to the stacking direction of the positive electrode sheet, the separator and the negative electrode sheet.

[0005] In the above technical solution, the thickness of the negative electrode sheet of the battery cell is 10μm to 30μm, that is, the negative electrode sheet is an ultra-thin negative electrode sheet, and the negative electrode sheet is relatively soft, making it difficult for the negative electrode sheet to extend beyond the positive electrode sheet in the first direction when stacked. By at least partially fixing the first extending portion of the two isolation segments adjacent to the positive electrode sheet to cover at least part of the edge of the positive electrode sheet, on the one hand, the position of the positive electrode sheet can be limited, thereby facilitating the negative electrode sheet to extend beyond the positive electrode sheet in the first direction, reducing the risk of lithium plating. On the other hand, it can prevent dendrites from growing in a circumferential direction, thereby reducing the risk of short circuits and improving the reliability of the battery cell.

[0006] As an optional technical solution of the embodiment of the present application, the thickness of the negative electrode sheet body is 10 μm to 20 μm.

[0007] In the above technical solution, the thickness of the negative electrode sheet body is thinner and the negative electrode sheet is softer. By fixing the first protruding parts of the two isolation segments adjacent to the positive electrode sheet at least partially to cover at least part of the edge of the positive electrode sheet, a better effect can be achieved.

[0008] As an optional technical solution of an embodiment of the present application, the negative electrode sheet main body includes a negative electrode current collector, and the material of the negative electrode current collector includes aluminum; the positive electrode sheet includes a positive electrode active material that can reversibly extract and embed sodium ions, and the positive electrode active material includes a sodium-containing compound.

[0009] In the above technical solution, the material of the negative electrode current collector includes aluminum, and the negative electrode sheet is softer. By fixing the first protruding portions of the two isolation segments adjacent to the positive electrode sheet at least partially to cover at least part of the edge of the positive electrode sheet, a better effect can be achieved.

[0010] As an optional technical solution of an embodiment of the present application, the electrode assembly includes a plurality of negative electrode sheets and a plurality of positive electrode sheets. Along the stacking direction, the plurality of negative electrode sheets are arranged at intervals, and the positive electrode sheet is arranged between two adjacent negative electrode sheets. The isolation segment separates the positive electrode sheet and the negative electrode sheet.

[0011] In the above technical solution, multiple negative and positive electrode sheets are stacked, with an isolation segment separating the positive and negative electrodes. This eliminates the need for a bending zone in the negative electrode sheet, which helps reduce volume and improve energy density. During manufacturing, a large negative electrode sheet can be continuously bent and stacked, and then cut to form multiple negative electrode sheets.

[0012] As an optional technical solution of the embodiment of the present application, along the first direction, the negative electrode sheet has a first edge, and the distance between the first edges of two adjacent negative electrode sheets is L1, which satisfies: 0≤L1≤2mm.

[0013] In the above technical solution, by making the gap between the first edges of two adjacent negative electrode sheets less than or equal to 2 mm, the first edges of multiple negative electrode sheets of the electrode assembly can be made more neat, which is beneficial to reducing volume occupancy and improving energy density.

[0014] As an optional technical solution of the embodiment of the present application, 0≤L1≤1mm.

[0015] In the above technical solution, by making the gap between the first edges of two adjacent negative electrode sheets less than or equal to 1 mm, the first edges of the multiple negative electrode sheets of the electrode assembly can be made more uniform, which is beneficial to reducing the volume occupation and improving the energy density.

[0016] As an optional technical solution of an embodiment of the present application, along the first direction, the negative electrode sheet has a first edge, and the isolation segment adjacent to the negative electrode sheet has a second edge closest to the first edge. The distance between the first edge and the second edge is L2, satisfying: 0≤L2≤2mm.

[0017] In the above technical solution, by making the distance between the first edge and the second edge less than or equal to 2 mm, the edges of the negative electrode sheet and the isolation segment can be made more neat, which is beneficial to reducing the volume occupied and improving the energy density.

[0018] As an optional technical solution of the embodiment of the present application, 0≤L2≤1mm.

[0019] In the above technical solution, by making the distance between the first edge and the second edge less than or equal to 1 mm, the edges of the negative electrode sheet and the isolation segment can be made more neat, which is beneficial to reducing the volume occupied and improving the energy density.

[0020] As an optional technical solution of the embodiment of the present application, along the first direction, the negative electrode sheet body extends beyond the positive electrode sheet by a dimension L3, which satisfies: 3mm≤L3≤10mm.

[0021] In the above technical solution, when L3 ≥ 3mm, the negative electrode sheet's main body extends significantly beyond the positive electrode sheet along the first direction, which helps meet the overhang design and reduces the risk of lithium plating. When L3 ≤ 10mm, the negative electrode sheet's main body extends less than the positive electrode sheet along the first direction, which helps reduce the negative electrode sheet's volume and improve energy density. Therefore, when 3mm ≤ L3 ≤ 10mm, both the overhang design and energy density can be met.

[0022] As an optional technical solution of the embodiment of the present application, 5mm≤L3≤8mm.

[0023] In the above technical solution, when L3 ≥ 5mm, the negative electrode sheet's main body extends further than the positive electrode sheet along the first direction, which is more conducive to meeting the overhang design and reducing the risk of lithium plating. When L3 ≤ 8mm, the negative electrode sheet's main body extends less than the positive electrode sheet along the first direction, which is conducive to reducing the volume of the negative electrode sheet and improving energy density. Therefore, when 5mm ≤ L3 ≤ 8mm, both the overhang design and energy density can be met.

[0024] As an optional technical solution of an embodiment of the present application, the positive electrode sheet includes a positive electrode ear unit and a positive electrode sheet main body, and the positive electrode ear unit is connected to one side of the positive electrode sheet main body along the second direction; the isolation segment has a second protruding portion that protrudes from the positive electrode sheet main body on both sides of the second direction, and the second protruding portions of the two isolation segments adjacent to the positive electrode sheet main body are at least partially fixedly connected to cover at least part of the edge of the positive electrode sheet main body, and the first direction, the second direction and the stacking direction are perpendicular to each other.

[0025] In the above technical solution, by at least partially fixedly connecting the second protruding portions of the two isolation segments adjacent to the positive electrode sheet body to cover at least a portion of the edge of the positive electrode sheet body, the position of the positive electrode sheet can be limited, thereby facilitating the negative electrode sheet to protrude beyond the positive electrode sheet along the first direction, thereby reducing the risk of lithium plating. Furthermore, the circumferential growth of dendrites can be prevented, thereby reducing the risk of short circuits and improving the reliability of the battery cell.

[0026] As an optional technical solution of the embodiment of the present application, the two isolation segments adjacent to the positive electrode sheet are connected to form a closed accommodation space, and the positive electrode sheet body is accommodated in the accommodation space.

[0027] In the above technical solution, by accommodating the positive electrode sheet body within the accommodation space, the position of the positive electrode sheet body can be limited, thereby facilitating the negative electrode sheet to extend beyond the positive electrode sheet along the first direction, thereby reducing the risk of lithium plating. Furthermore, the circumferential growth of dendrites can be further prevented, thereby reducing the risk of short circuits and improving the reliability of the battery cell.

[0028] In the second aspect, an embodiment of the present application also provides an electrode assembly, which includes a negative electrode sheet, an isolation member and a positive electrode sheet, wherein the positive electrode sheet, the isolation member and the negative electrode sheet are stacked, and the negative electrode sheet includes a negative electrode ear unit and a negative electrode sheet body, wherein the negative electrode ear unit is connected to one side of the negative electrode sheet body, and the thickness of the negative electrode sheet body is 10μm to 30μm; the isolation member has an isolation segment separating the positive electrode sheet and the negative electrode sheet, and the isolation segment has a first protruding portion that protrudes from the positive electrode sheet on both sides of the first direction, and the first protruding portions of the two isolation segments adjacent to the positive electrode sheet are at least partially fixedly connected to cover at least part of the edge of the positive electrode sheet, and the first direction is perpendicular to the stacking direction of the positive electrode sheet, the isolation member and the negative electrode sheet.

[0029] As an optional technical solution of the embodiment of the present application, the thickness of the negative electrode sheet body is 10 μm to 20 μm.

[0030] In the above technical solution, the thickness of the negative electrode sheet body is thinner and the negative electrode sheet is softer. By fixing the first protruding parts of the two isolation segments adjacent to the positive electrode sheet at least partially to cover at least part of the edge of the positive electrode sheet, a better effect can be achieved.

[0031] As an optional technical solution of an embodiment of the present application, the negative electrode sheet main body includes a negative electrode current collector, and the material of the negative electrode current collector includes aluminum; the positive electrode sheet includes a positive electrode active material that can reversibly extract and embed sodium ions, and the positive electrode active material includes a sodium-containing compound.

[0032] In the above technical solution, the material of the negative electrode current collector includes aluminum, and the negative electrode sheet is softer. By fixing the first protruding portions of the two isolation segments adjacent to the positive electrode sheet at least partially to cover at least part of the edge of the positive electrode sheet, a better effect can be achieved.

[0033] As an optional technical solution of an embodiment of the present application, the electrode assembly includes a plurality of negative electrode sheets and a plurality of positive electrode sheets. Along the stacking direction, the plurality of negative electrode sheets are arranged at intervals, and the positive electrode sheet is arranged between two adjacent negative electrode sheets. The isolation segment separates the positive electrode sheet and the negative electrode sheet.

[0034] In the above technical solution, multiple negative and positive electrode sheets are stacked, with an isolation segment separating the positive and negative electrodes. This eliminates the need for a bending zone in the negative electrode sheet, which helps reduce volume and improve energy density. During manufacturing, a large negative electrode sheet can be continuously bent and stacked, and then cut to form multiple negative electrode sheets.

[0035] As an optional technical solution of the embodiment of the present application, along the first direction, the negative electrode sheet has a first edge, and the distance between the first edges of two adjacent negative electrode sheets is L1, which satisfies: 0≤L1≤2mm.

[0036] In the above technical solution, by making the gap between the first edges of two adjacent negative electrode sheets less than or equal to 2 mm, the first edges of multiple negative electrode sheets of the electrode assembly can be made more neat, which is beneficial to reducing volume occupancy and improving energy density.

[0037] As an optional technical solution of the embodiment of the present application, 0≤L1≤1mm.

[0038] In the above technical solution, by making the gap between the first edges of two adjacent negative electrode sheets less than or equal to 1 mm, the first edges of the multiple negative electrode sheets of the electrode assembly can be made more uniform, which is beneficial to reducing the volume occupation and improving the energy density.

[0039] As an optional technical solution of an embodiment of the present application, along the first direction, the negative electrode sheet has a first edge, and the isolation segment adjacent to the negative electrode sheet has a second edge closest to the first edge. The distance between the first edge and the second edge is L2, satisfying: 0≤L2≤2mm.

[0040] In the above technical solution, by making the distance between the first edge and the second edge less than or equal to 2 mm, the edges of the negative electrode sheet and the isolation segment can be made more neat, which is beneficial to reducing the volume occupied and improving the energy density.

[0041] As an optional technical solution of the embodiment of the present application, 0≤L2≤1mm.

[0042] In the above technical solution, by making the distance between the first edge and the second edge less than or equal to 1 mm, the edges of the negative electrode sheet and the isolation segment can be made more neat, which is beneficial to reducing the volume occupied and improving the energy density.

[0043] As an optional technical solution of the embodiment of the present application, along the first direction, the negative electrode sheet body extends beyond the positive electrode sheet by a dimension L3, which satisfies: 3mm≤L3≤10mm.

[0044] In the above technical solution, when L3 ≥ 3mm, the negative electrode sheet's main body extends significantly beyond the positive electrode sheet along the first direction, which helps meet the overhang design and reduces the risk of lithium plating. When L3 ≤ 10mm, the negative electrode sheet's main body extends less than the positive electrode sheet along the first direction, which helps reduce the negative electrode sheet's volume and improve energy density. Therefore, when 3mm ≤ L3 ≤ 10mm, both the overhang design and energy density can be met.

[0045] As an optional technical solution of the embodiment of the present application, 5mm≤L3≤8mm.

[0046] In the above technical solution, when L3 ≥ 5mm, the negative electrode sheet's main body extends further than the positive electrode sheet along the first direction, which is more conducive to meeting the overhang design and reducing the risk of lithium plating. When L3 ≤ 8mm, the negative electrode sheet's main body extends less than the positive electrode sheet along the first direction, which is conducive to reducing the volume of the negative electrode sheet and improving energy density. Therefore, when 5mm ≤ L3 ≤ 8mm, both the overhang design and energy density can be met.

[0047] In a third aspect, an embodiment of the present application further provides a method for manufacturing an electrode assembly, the method comprising: step S100: providing a positive electrode sheet, an isolating member and a negative electrode sheet, the negative electrode sheet comprising a negative electrode ear unit and a negative electrode sheet body, the negative electrode ear unit being connected to one side of the negative electrode sheet body, and the thickness of the negative electrode sheet body being 10 μm to 30 μm; step S200: stacking the positive electrode sheet, the isolating member and the negative electrode sheet, the isolating member having an isolating segment separating the positive electrode sheet and the negative electrode sheet, the isolating segment having a first protruding portion extending beyond the positive electrode sheet on both sides in a first direction, the first direction being perpendicular to the stacking direction of the positive electrode sheet, the isolating member and the negative electrode sheet; step S300: at least partially fixing the first protruding portions of the two isolating segments adjacent to the positive electrode sheet to cover at least a portion of the edge of the positive electrode sheet.

[0048] As an optional technical solution of the embodiment of the present application, in the step S100, the thickness of the negative electrode sheet body is 10 μm to 20 μm.

[0049] In the above technical solution, the thickness of the negative electrode sheet body is thinner and the negative electrode sheet is softer. By fixing the first protruding parts of the two isolation segments adjacent to the positive electrode sheet at least partially to cover at least part of the edge of the positive electrode sheet, a better effect can be achieved.

[0050] As an optional technical solution of the embodiment of the present application, in step S200, the difference between the maximum thickness of the negative electrode sheet body and the minimum thickness of the negative electrode sheet is less than or equal to 2 μm.

[0051] In the above technical solution, the difference between the maximum thickness of the negative electrode sheet and the minimum thickness of the negative electrode sheet is less than or equal to 2 μm, that is, the thickness of each position of the negative electrode sheet is roughly the same. In other words, there is no need to make marks on the negative electrode sheet.

[0052] As an optional technical solution of the embodiment of the present application, the thickness of each position of the negative electrode sheet body is equal.

[0053] In the above technical solution, the thickness of each position of the negative electrode sheet body is equal, and there is no need to make marks on the negative electrode sheet body.

[0054] As an optional technical solution of an embodiment of the present application, step S200 includes: step S210: making the positive electrode sheet, the separator and the negative electrode sheet into a composite electrode sheet, the composite electrode sheet includes multiple positive electrode sheets, and the multiple positive electrode sheets are alternately arranged on both sides of the negative electrode sheet, and along the length direction of the composite electrode sheet, the part of the composite electrode sheet located between two adjacent positive electrode sheets is a bending section; step S220: bending the bending section so that the positive electrode sheet, the separator and the negative electrode sheet are stacked.

[0055] In the above technical solution, a composite electrode is first made, and the bending section of the composite electrode is relatively weak. The bending section can be bent to stack the positive electrode, the separator and the negative electrode, making the manufacturing simple and convenient, and is conducive to making the negative electrode extend beyond the positive electrode along the first direction, thereby reducing the risk of lithium plating.

[0056] As an optional technical solution of an embodiment of the present application, after step S300, the electrode assembly manufacturing method further includes: step S400: cutting the negative electrode sheet and the separator to remove the portion of the negative electrode sheet and the separator located at the bending section of the composite electrode sheet.

[0057] In the above technical solution, since the negative electrode sheet is relatively soft, the bent section of the composite electrode sheet is prone to a large curvature. By cutting the negative electrode sheet and separator, and removing the portion of the negative electrode sheet and separator located in the bent section of the composite electrode sheet, the electrode assembly is reshaped. On the one hand, this helps to smooth the interface of the electrode assembly, reducing the gap between the positive and negative electrode sheets, thereby shortening the ion path. On the other hand, it helps to reduce the volume occupied and improve energy density.

[0058] As an optional technical solution of the embodiment of the present application, in step S400, along the first direction, the negative electrode sheet has a first edge, and the distance between the first edges of two adjacent negative electrode sheets is controlled within 2 mm.

[0059] In the above technical solution, by ensuring that the gap between the first edges of two adjacent negative electrode sheets is less than or equal to 2 mm, the cut surface is relatively neat. On the one hand, the gap between the positive and negative electrode sheets is reduced, thereby shortening the ion path. On the other hand, it is conducive to reducing the volume occupied and improving the energy density.

[0060] As an optional technical solution of the embodiment of the present application, in step S400, along the first direction, the negative electrode sheet has a first edge, and the distance between the first edges of two adjacent negative electrode sheets is controlled within 1 mm.

[0061] In the above technical solution, by ensuring that the gap between the first edges of two adjacent negative electrode sheets is less than or equal to 1 mm, the cut surface is made more uniform. On the one hand, the gap between the positive and negative electrode sheets is reduced, thereby shortening the ion path. On the other hand, it is conducive to reducing the volume occupied and improving the energy density.

[0062] As an optional technical solution of the embodiment of the present application, in the step S400, the distance between the cutting position of the negative electrode sheet and the separator and the positive electrode sheet is controlled within 3 mm to 10 mm along the first direction.

[0063] In the above technical solution, when the distance between the cutting position of the negative electrode sheet and the separator and the positive electrode sheet is greater than or equal to 3mm, the negative electrode sheet is larger than the positive electrode sheet along the first direction, which is conducive to meeting the overhang design and can reduce the risk of lithium plating. When the distance between the cutting position of the negative electrode sheet and the separator and the positive electrode sheet is less than or equal to 10mm, the negative electrode sheet is not too large in the first direction compared to the positive electrode sheet, which is conducive to reducing the volume of the negative electrode sheet and improving the energy density. Therefore, when the distance between the cutting position of the negative electrode sheet and the separator and the positive electrode sheet is within 3mm to 10mm, it can both meet the overhang design and improve the energy density.

[0064] As an optional technical solution of the embodiment of the present application, in the step S400, the distance between the cutting position of the negative electrode sheet and the separator and the positive electrode sheet is controlled within 5 mm to 8 mm along the first direction.

[0065] In the above technical solution, when the distance between the cutting position of the negative electrode sheet and the separator and the positive electrode sheet is greater than or equal to 5mm, the negative electrode sheet is larger than the positive electrode sheet along the first direction, which is conducive to meeting the overhang design and can reduce the risk of lithium plating. When the distance between the cutting position of the negative electrode sheet and the separator and the positive electrode sheet is less than or equal to 8mm, the negative electrode sheet is not too large in the first direction compared to the positive electrode sheet, which is conducive to reducing the volume of the negative electrode sheet and improving the energy density. Therefore, when the distance between the cutting position of the negative electrode sheet and the separator and the positive electrode sheet is within 5mm to 8mm, it can both meet the overhang design and improve the energy density.

[0066] As an optional technical solution of an embodiment of the present application, in step S400, the distance between the first edge of the cut negative electrode sheet and the second edge of the isolation segment adjacent to the negative electrode sheet closest to the first edge is controlled within 2 mm along the first direction.

[0067] In the above technical solution, by making the distance between the first edge and the second edge less than or equal to 2 mm, the edges of the negative electrode sheet and the isolation segment can be made more neat, which is beneficial to reducing the volume occupied and improving the energy density.

[0068] As an optional technical solution of an embodiment of the present application, in step S400, the distance between the first edge of the cut negative electrode sheet and the second edge of the separator closest to the first edge is controlled within 1 mm along the first direction.

[0069] In the above technical solution, by making the distance between the first edge and the second edge less than or equal to 1 mm, the edges of the negative electrode sheet and the isolation segment can be made more neat, which is beneficial to reducing the volume occupied and improving the energy density.

[0070] As an optional technical solution of an embodiment of the present application, the step S300 includes: step S310: fixing the first protruding portions of the two isolation segments adjacent to the positive electrode sheet at least partially by hot pressing.

[0071] In the above technical solution, the first protruding portions of the two isolation segments are at least partially fixedly connected by hot pressing. On the one hand, this facilitates manufacturing, allowing the isolation segments on both sides of each positive electrode sheet to be connected simultaneously. On the other hand, hot pressing is less likely to damage the positive and negative electrode sheets, which helps improve the reliability of the electrode assembly.

[0072] In a fourth aspect, an embodiment of the present application further provides a battery device, which includes the above-mentioned battery cell.

[0073] In a fifth aspect, an embodiment of the present application further provides an electrical device, which includes the above-mentioned battery cell, and the battery cell is used to provide electrical energy to the electrical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] 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 show 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 be obtained based on these drawings without creative work.

[0075] Figure 1 A schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0076] Figure 2 An exploded view of a battery device provided in some embodiments of the present application;

[0077] Figure 3 A schematic structural diagram of a battery cell provided in some embodiments of the present application;

[0078] Figure 4 An exploded view of a battery cell provided in some embodiments of the present application;

[0079] Figure 5 A cross-sectional view of an electrode assembly provided in some embodiments of the present application at a first viewing angle;

[0080] Figure 6 A cross-sectional view of a negative electrode sheet provided in some embodiments of the present application;

[0081] Figure 7 A cross-sectional view of an electrode assembly provided in some embodiments of the present application at a second viewing angle;

[0082] Figure 8 A schematic block diagram of a method for manufacturing an electrode assembly according to some embodiments of the present application;

[0083] Figure 9 A schematic block diagram of a method for manufacturing an electrode assembly provided in some other embodiments of the present application;

[0084] Figure 10 A schematic diagram of the structure of a composite electrode provided in some embodiments of the present application;

[0085] Figure 11 A cross-sectional view of a product after step S220 provided in some embodiments of the present application;

[0086] Figure 12 A schematic block diagram of a method for manufacturing an electrode assembly according to some other embodiments of the present application;

[0087] Figure 13 A schematic block diagram of a method for manufacturing an electrode assembly provided in some embodiments of the present application.

[0088] Icons: 10-case; 11-first part; 12-second part; 20-battery cell; 21-housing; 211-housing; 212-end cap; 22-electrode assembly; 221-main body; 222-negative tab; 223-positive tab; 224-negative sheet; 2241-negative tab unit; 2242-negative sheet body; 22421-negative current collector; 2243-first edge; 225-separator; 2251-isolation segment; 22511-first protruding portion; 22512-second edge; 22513-second protruding portion; 226-positive electrode sheet; 2261-positive electrode ear unit; 2262-positive electrode sheet body; 227-accommodation space; 228-composite electrode sheet; 2281-bending segment; 23-insulating member; 24-electrode terminal; 30-electrode assembly manufacturing method; 100-battery device; 200-controller; 300-motor; 1000-vehicle. DETAILED DESCRIPTION

[0089] To make the purpose, technical solutions, and advantages of the embodiments 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 without making creative efforts are within the scope of protection of this application.

[0090] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" 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.

[0091] 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.

[0092] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0093] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0094] 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.

[0095] The term "plurality" used in this application refers to two or more (including two).

[0096] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0097] Battery cells include but are not limited to lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0098] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process, active ions (such as lithium ions) move back and forth between the positive and negative electrodes. A separator, placed between the positive and negative electrodes, reduces the risk of short circuits while allowing active ions to pass through.

[0099] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0100] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0101] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum with a surface silver plating treatment, stainless steel with a surface silver plating treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0102] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for battery cells may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include but are not limited to lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3Mn 1 / 3O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0103] In some embodiments, a positive electrode may utilize a metal foam. The metal foam may include nickel foam, copper foam, aluminum foam, alloy foam, or the like. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not include a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled or / and deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0104] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0105] As an example, the negative electrode current collector can be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium can be used. The metal foam can be nickel foam, copper foam, aluminum foam, alloy foam, etc. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0106] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0107] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0108] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0109] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0110] In some embodiments, the separator is a separator membrane, which can be any known porous separator membrane with good chemical and mechanical stability.

[0111] As an example, the separator can be made of at least one of fiberglass, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film. In the case of a multi-layer composite film, the materials of each layer can be the same or different. The separator can be a separate component positioned between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0112] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0113] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel, or solid. Liquid electrolytes include an electrolyte salt and a solvent.

[0114] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium bisoxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0115] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0116] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0117] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0118] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, or the like.

[0119] As an example, the inorganic solid electrolyte may include an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0120] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0121] In some embodiments, the electrode assembly is a laminate structure.

[0122] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0123] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0124] As an example, a plurality of separators may be provided, each of which is disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0125] As an example, the separator may be provided continuously and disposed between any adjacent positive electrode sheets or negative electrode sheets by folding.

[0126] In some embodiments, the shape of the electrode assembly can be flat or polygonal.

[0127] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0128] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0129] In some embodiments, the housing can be a sealed structure or a non-sealed structure. For example, when the housing is a sealed structure, the housing can protect the electrode assembly and, to a certain extent, prevent leakage of the electrolyte. When the housing is a non-sealed structure, the housing can also protect the electrode assembly. A sealing bag can be included between the housing and the electrode assembly to encapsulate the electrode assembly and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating member or an aluminum-plastic film.

[0130] As an example, the battery cell may be a prismatic battery cell, a soft-pack battery cell, or a battery cell of another shape. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, and a polygonal battery cell. The polygonal battery cell is, for example, a hexagonal battery cell.

[0131] The battery apparatus mentioned in the embodiments of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple battery cells, which are connected in series, parallel, or hybrid via a busbar.

[0132] In some embodiments, a battery cell assembly is generally formed by arranging a plurality of battery cells. As an example, the battery cell assembly may be a battery module, which is formed by arranging and fixing a plurality of battery cells to form an independent module.

[0133] As an example, a battery module may be formed by bundling a plurality of battery cells by cable ties.

[0134] In some embodiments, the battery device may be a battery pack, which may include a case and one or more battery cell assemblies, wherein the battery cell assemblies are housed in the case.

[0135] As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the box by fixing the battery module in the box.

[0136] As an example, the battery cell assembly may also be housed in the box by directly fixing the plurality of battery cells to the box.

[0137] For example, the housing may include a first portion and a second portion. The first and second portions engage to form an enclosed space within the housing to house the battery cell assembly. Enclosed here means covered or closed, and can be either sealed or unsealed. The first portion may be a top cover or a bottom plate.

[0138] As an example, the box body may include a top cover, a frame, and a bottom plate, wherein the top cover and the bottom plate are respectively connected to the frame, so that a closed space is formed inside the box body to accommodate the battery cell assembly.

[0139] As an example, the box body can be used as a part of the chassis structure of the vehicle. For example, the top cover of the box body can become at least a part of the floor of the vehicle, or the frame of the box body can become at least a part of the crossbeam and longitudinal beam of the vehicle.

[0140] In some embodiments, the battery device refers to an energy storage device, which includes a box with a door on at least one side. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0141] Currently, market developments indicate that batteries are increasingly being used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. As battery applications continue to expand, market demand is also growing.

[0142] The development of battery technology requires simultaneous consideration of multiple design factors, such as energy density, cycle life, discharge capacity, charge and discharge rate, and other performance parameters. Furthermore, battery reliability must be considered. However, current battery reliability is relatively poor.

[0143] Batteries include electrode assemblies, which are the components in the battery where electrochemical reactions occur. Electrode assemblies are primarily composed of stacked positive electrode sheets, separators, and negative electrode sheets. When manufacturing electrode assemblies, the amount by which the negative electrode sheet protrudes beyond the positive electrode sheet must be within a preset range; otherwise, the manufactured electrode assembly is susceptible to lithium deposition. However, when using ultra-thin negative electrode sheets for lamination, due to their thinness and softness, it is difficult to ensure that the amount by which the negative electrode sheet protrudes beyond the positive electrode sheet is within a preset range, resulting in poor reliability of current batteries.

[0144] In view of this, an embodiment of the present application provides a battery cell, which includes a housing and an electrode assembly, and the electrode assembly is accommodated in the housing. The electrode assembly includes a negative electrode sheet, a separator and a positive electrode sheet, and the positive electrode sheet, the separator and the negative electrode sheet are stacked. The negative electrode sheet includes a negative electrode ear unit and a negative electrode sheet body, and the negative electrode ear unit is connected to one side of the negative electrode sheet body, and the thickness of the negative electrode sheet body is 10μm to 30μm. The separator has an isolation segment that separates the positive electrode sheet and the negative electrode sheet, and the isolation segment has a first protruding portion that protrudes from the positive electrode sheet on both sides of the first direction, and the first protruding portions of the two isolation segments adjacent to the positive electrode sheet are at least partially fixedly connected to cover at least part of the edge of the positive electrode sheet. The first direction is perpendicular to the stacking direction of the positive electrode sheet, the separator and the negative electrode sheet.

[0145] The thickness of the negative electrode sheet of this battery cell is 10μm to 30μm, that is, the negative electrode sheet is ultra-thin and relatively soft, making it difficult for the negative electrode sheet to extend beyond the positive electrode sheet in the first direction when stacked. By at least partially fixing the first extending portions of the two isolation segments adjacent to the positive electrode sheet to cover at least part of the edge of the positive electrode sheet, on the one hand, the position of the positive electrode sheet can be limited, thereby facilitating the negative electrode sheet to extend beyond the positive electrode sheet in the first direction and reducing the risk of lithium plating. On the other hand, it can prevent dendrites from growing in a circular manner, thereby reducing the risk of short circuits and improving the reliability of the battery cell.

[0146] The technical solutions described in the embodiments of the present application are applicable to various electrical devices that use battery cells and battery devices, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, electric tools, vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft, etc.

[0147] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0148] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of the present application. A battery device 100 is disposed within vehicle 1000. Battery device 100 can be located at the bottom, front, or rear of vehicle 1000. Battery device 100 can be used to power vehicle 1000. For example, battery device 100 can serve as the operating power source of vehicle 1000.

[0149] The vehicle 1000 may further include a controller 200 and a motor 300 . The controller 200 is used to control the battery device 100 to supply power to the motor 300 , for example, to meet the power requirements of the vehicle 1000 during startup, navigation, and driving.

[0150] In some embodiments of the present application, the battery device 100 can not only serve as the operating power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0151] Please refer to Figure 2 , Figure 2 This is an exploded view of a battery device 100 provided in some embodiments of the present application. The battery device 100 may include a housing 10 and a battery cell 20 , wherein the housing 10 is used to accommodate the battery cell 20 .

[0152] Among them, a closed space for accommodating the battery cell 20 is formed inside the box body 10. The box body 10 can adopt a variety of structures. In some embodiments, the box body 10 may include a first part 11 and a second part 12, and the first part 11 and the second part 12 are buckled with each other. The first part 11 and the second part 12 can be in various shapes, such as a cuboid, a cylinder, etc. The first part 11 can be a hollow structure with one side open, and the second part 12 can also be a hollow structure with one side open, and the open side of the second part 12 is buckled with the open side of the first part 11 to form a box body 10 with a closed space. The first part 11 can also be a hollow structure with one side open, and the second part 12 can be a plate-like structure, and the second part 12 is buckled with the open side of the first part 11 to form a box body 10 with an accommodating space.

[0153] In the battery device 100, there can be one or more battery cells 20. If there are multiple battery cells 20, the multiple battery cells 20 can be connected in series, parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. Multiple battery cells 20 can be connected in series, parallel, or in a hybrid connection to form a battery module, which is then connected in series, parallel, or in a hybrid connection to form a single unit and housed within the housing 10. Alternatively, all battery cells 20 can be directly connected in series, parallel, or in a hybrid connection, and then the entire unit formed by all battery cells 20 is housed within the housing 10.

[0154] In some embodiments, the battery device 100 may further include a busbar component, through which the multiple battery cells 20 can be electrically connected to each other, thereby enabling series connection, parallel connection, or hybrid connection of the multiple battery cells 20. The busbar component may be a metal conductor, such as copper, iron, aluminum, stainless steel, or aluminum alloy.

[0155] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 , Figure 3 This is a schematic structural diagram of a battery cell 20 provided in some embodiments of the present application. Figure 4 An exploded view of a battery cell 20 provided in some embodiments of the present application. Figure 5 This is a cross-sectional view of the electrode assembly 22 provided in some embodiments of the present application at a first viewing angle. Figure 6 A cross-sectional view of a negative electrode sheet 224 provided in some embodiments of the present application. Embodiments of the present application provide a battery cell 20, comprising a housing 21 and an electrode assembly 22, with the electrode assembly 22 housed within the housing 21. The electrode assembly 22 comprises a negative electrode sheet 224, a separator 225, and a positive electrode sheet 226. The positive electrode sheet 226, separator 225, and negative electrode sheet 224 are stacked. The negative electrode sheet 224 comprises a negative electrode tab unit 2241 and a negative electrode sheet body 2242. The negative electrode tab unit 2241 is connected to one side of the negative electrode sheet body 2242. The thickness of the negative electrode sheet body 2242 is 10 μm to 30 μm. The separator 225 includes a separator segment 2251 that separates the positive electrode sheet 226 from the negative electrode sheet 224. The separator segment 2251 includes a first protruding portion 22511 that protrudes from the positive electrode sheet 226 on both sides in a first direction. The first protruding portions 22511 of two adjacent separator segments 2251 of the positive electrode sheet 226 are at least partially fixedly connected to each other to cover at least a portion of the edge of the positive electrode sheet 226. The first direction is perpendicular to the stacking direction of the positive electrode sheet 226, the separator 225, and the negative electrode sheet 224.

[0156] The battery cell 20 refers to the smallest unit constituting the battery device 100 .

[0157] In some embodiments, the housing 21 may include a shell 211 and an end cap 212, wherein the shell 211 has an opening and the end cap 212 closes the opening of the shell 211. The term "closed" here means to cover or close, and may be sealed or non-sealed.

[0158] The end cap 212 refers to a component that covers the opening of the shell 211 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 212 can be adapted to the shape of the shell 211 to match the shell 211. Optionally, the end cap 212 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 212 is not easily deformed when squeezed or collided, so that the battery cell 20 can have a higher structural strength and improved reliability. The material of the end cap 212 can include but is not limited to copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. The battery cell 20 also includes an insulating member 23, which is arranged on the inner side of the end cap 212. The insulating member 23 can be used to isolate the electrical connection components in the shell 211 from the end cap 212 to reduce the risk of short circuit. Exemplarily, the insulating member 23 can be plastic, rubber, etc.

[0159] The housing 211 is a component that cooperates with the end cap 212 to form the internal environment of the battery cell 20. This internal environment can be used to accommodate the electrode assembly 22, electrolyte, and other components. The housing 211 and end cap 212 can be separate components. An opening can be provided in the housing 211, and the end cap 212 is placed over the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 212 and housing 211 can be integrated. Specifically, the end cap 212 and housing 211 can form a common joint surface before other components are inserted into the housing. When the interior of the housing 211 needs to be enclosed, the end cap 212 is placed over the housing 211. The housing 211 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the housing 211 can be determined based on the specific shape and size of the electrode assembly 22. The material of the housing 211 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0160] In embodiments where the housing 211 is open at one end, one end cap 212 may be provided. In embodiments where the housing 211 is open at two opposite ends, two end caps 212 may be provided. The two end caps 212 respectively seal the two openings of the housing 211, and the two end caps 212 and the housing 211 together define a receiving space for the electrode assembly 22.

[0161] The electrode assembly 22 is the component within the battery cell 20 where the electrochemical reaction occurs. One or more electrode assemblies 22 may be contained within the housing 211. The electrode assembly 22 is primarily formed by stacking a positive electrode sheet 226 and a negative electrode sheet 224, with a separator 225 typically provided between the positive and negative electrode sheets 226 and 224. The portions of the positive and negative electrode sheets 226 and 224 containing active material constitute the main body 221 of the electrode assembly 22. The portions of the positive electrode sheet 226 without active material constitute the positive tab unit 2261, and the portions of the negative electrode sheet 224 without active material constitute the negative tab unit 2241. To ensure high current flow without melting, multiple positive tab units 2261 are stacked together to form the positive tab 223, and multiple negative tab units 2241 are stacked together to form the negative tab 222. The positive and negative tabs 223 and 222 can be located together at one end of the main body 221 or separately at opposite ends. During the charge and discharge process of the battery device 100 , the positive electrode active material and the negative electrode active material react with the electrolyte.

[0162] The negative electrode sheet 224 includes a negative electrode tab unit 2241 and a negative electrode sheet body 2242 . The negative electrode tab unit 2241 is connected to one side of the negative electrode sheet body 2242 . The negative electrode sheet body 2242 contains negative electrode active material, while the negative electrode tab unit 2241 does not contain negative electrode active material.

[0163] “The thickness of the negative electrode sheet main body 2242 is 10 μm to 30 μm” means that when the battery cell 20 is fully discharged to 0% SOC, the thickness of the negative electrode sheet main body 2242 is 10 μm to 30 μm. Figure 6 The thickness of the negative electrode sheet main body 2242 can be represented by H, that is, 10 μm ≤ H ≤ 30 μm. When 10 μm ≤ H ≤ 30 μm, the negative electrode sheet 224 is an ultra-thin negative electrode sheet.

[0164] The thickness of the negative electrode sheet main body 2242 can be: H = 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm, 28 μm, 30 μm, etc.

[0165] When there are multiple separators 225 and each separator 225 is disposed between adjacent positive electrode sheets 226 or negative electrode sheets 224, the separator 225 as a whole can serve as an isolation segment 2251. When the separator 225 is a continuous structure disposed between any adjacent positive electrode sheets 226 or negative electrode sheets 224 by folding, the separator 225 includes multiple isolation segments 2251, which are arranged along the stacking direction of the positive electrode sheets 226, the separator 225, and the negative electrode sheets 224, and each isolation segment 2251 is used to separate the positive electrode sheet 226 from the negative electrode sheet 224.

[0166] The first protruding portion 22511 is the portion of the isolation segment 2251 that protrudes from the positive electrode sheet 226 along the first direction. Both sides of the isolation segment 2251 along the first direction protrude from the positive electrode sheet 226. In other words, the isolation segment 2251 has two first protruding portions 22511, which are spaced apart along the first direction.

[0167] Please refer to Figure 5 The stacking direction of the positive electrode sheet 226, the separator 225 and the negative electrode sheet 224 is the X direction shown in the figure. The first direction is perpendicular to the stacking direction and can be the Y direction shown in the figure.

[0168] Please refer to Figure 5 , along the stacking direction, the first protruding portions 22511 of the two isolation segments 2251 on both sides of the positive electrode sheet 226 are fixedly connected. When connected, the first protruding portion 22511 of one isolation segment 2251 is fixedly connected to the first protruding portion 22511 of the other isolation segment 2251 on the same side as the first protruding portion 22511. Figure 5 , the first protruding portion 22511 located on the left side of one isolation segment 2251 is connected to the first protruding portion 22511 located on the left side of another isolation segment 2251, and the first protruding portion 22511 located on the right side of one isolation segment 2251 is connected to the first protruding portion 22511 located on the right side of another isolation segment 2251.

[0169] The thickness of the negative electrode sheet 2242 of the battery cell 20 is 10μm to 30μm, meaning that the negative electrode sheet 224 is ultra-thin and relatively soft, making it difficult for the negative electrode sheet 224 to extend beyond the positive electrode sheet 226 along the first direction when stacked. By at least partially fixing the first extending portions 22511 of the two isolation segments 2251 adjacent to the positive electrode sheet 226 to cover at least a portion of the edge of the positive electrode sheet 226, the position of the positive electrode sheet 226 can be limited, thereby facilitating the negative electrode sheet 224 to extend beyond the positive electrode sheet 226 along the first direction, thereby reducing the risk of lithium plating. Furthermore, this can prevent dendrites from growing in a circular manner, thereby reducing the risk of short circuits and improving the reliability of the battery cell 20.

[0170] In some embodiments, the battery cell 20 may further include an electrode terminal 24, which is disposed on the outer casing 21. The electrode terminal 24 is used to electrically connect to the tab of the electrode assembly 22 to input or output electrical energy from the battery cell 20. The electrode terminal 24 may be disposed on the shell 211 of the outer casing 21 or on the end cap 212 of the outer casing 21. The electrode terminal 24 and the tab may be directly connected, for example, by welding the electrode terminal 24 to the tab. The electrode terminal 24 and the tab may also be indirectly connected, for example, by indirectly connecting the electrode terminal 24 and the tab via a current collecting member. The current collecting member may be a metal conductor, such as copper, iron, aluminum, steel, or an aluminum alloy.

[0171] As an example, Figure 3 and Figure 4 As shown, an opening is formed at one end of the housing 211. There is only one end cap 212 in the outer shell 21, and each end cap 212 seals the opening of the housing 211. Two electrode terminals 24 are provided on the end cap 212, and the two electrode terminals 24 are respectively a positive electrode terminal and a negative electrode terminal. A positive electrode tab 223 and a negative electrode tab 222 are formed on the end of the electrode assembly 22 facing the end cap 212. The positive electrode terminal is electrically connected to the positive electrode tab 223, and the negative electrode terminal is electrically connected to the negative electrode tab 222.

[0172] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 In some embodiments, the thickness of the negative electrode sheet main body 2242 is 10 μm to 20 μm.

[0173] The thickness of the negative electrode sheet main body 2242 can be: H = 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, etc.

[0174] The thickness of the negative electrode sheet main body 2242 is thinner and the negative electrode sheet 224 is softer. By at least partially fixing the first protruding portions 22511 of the two isolation segments 2251 adjacent to the positive electrode sheet 226 to cover at least part of the edge of the positive electrode sheet 226, a better effect can be achieved.

[0175] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 In some embodiments, the negative electrode sheet body 2242 includes a negative electrode current collector 22421, and the material of the negative electrode current collector 22421 includes aluminum. The positive electrode sheet 226 includes a positive electrode active material capable of reversibly extracting and inserting sodium ions, and the positive electrode active material includes a sodium-containing compound.

[0176] The negative electrode current collector 22421 is made of aluminum, and the positive electrode active material includes a compound containing sodium. Thus, the battery cell 20 is a sodium ion battery cell.

[0177] The negative electrode current collector 22421 is made of aluminum. The negative electrode sheet 224 is softer. By at least partially fixing the first protruding portions 22511 of the two isolation segments 2251 adjacent to the positive electrode sheet 226 to cover at least part of the edge of the positive electrode sheet 226, a better effect can be achieved.

[0178] In other embodiments, the negative electrode current collector 22421 is made of at least one of copper, nickel, molybdenum, titanium, niobium, and iron. The negative electrode current collector 22421 can be made of a pure metal or an alloy. For example, the negative electrode current collector 22421 can be made of copper, nickel, or stainless steel. In some embodiments, the negative electrode sheet body 2242 further includes a functional coating disposed on the negative electrode current collector 22421. The functional coating may include a conductive enhancement coating, a metal affinity coating, and the like.

[0179] In other embodiments, the negative electrode current collector 22421 can be a current collector that combines support capabilities and functional elements, such as carbon cloth, carbon film, carbonaceous, porous current collector, alloyed modified current collector, lithium / sodium-philic modified current collector, etc.

[0180] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 In some embodiments, the electrode assembly 22 includes a plurality of negative electrode sheets 224 and a plurality of positive electrode sheets 226. Along the stacking direction, the plurality of negative electrode sheets 224 are spaced apart, and the positive electrode sheet 226 is disposed between two adjacent negative electrode sheets 224. An isolation segment 2251 separates the positive electrode sheet 226 from the negative electrode sheet 224.

[0181] There are multiple positive electrode sheets 226 and multiple negative electrode sheets 224 , respectively. The multiple positive electrode sheets 226 and the multiple negative electrode sheets 224 are alternately stacked, and an isolation section 2251 is provided between the positive electrode sheet 226 and the negative electrode sheet 224 .

[0182] Multiple negative electrode sheets 224 and multiple positive electrode sheets 226 are stacked, with isolation segments 2251 separating the positive electrode sheets 226 and negative electrode sheets 224. This eliminates the need for bending regions in the negative electrode sheets 224, reducing their footprint and increasing energy density. During manufacturing, a large negative electrode sheet 224 can be continuously bent and stacked, and then cut to form multiple smaller negative electrode sheets 224.

[0183] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 In some embodiments, along the first direction, the negative electrode sheet 224 has a first edge 2243 , and the distance between the first edges 2243 of two adjacent negative electrode sheets 224 is L1 , satisfying: 0≤L1≤2mm.

[0184] The first edge 2243 specifically refers to an edge of the negative electrode sheet 224 along the first direction.

[0185] L1 represents the distance between the first edges 2243 of two adjacent negative electrode sheets 224. It should be noted that the first edges 2243 of the two negative electrode sheets 224 are located on the same side of the positive electrode sheet 226 along the first direction.

[0186] The distance between the first edges 2243 of two adjacent negative electrode sheets 224 can be: L1 = 2 mm, 1.8 mm, 1.5 mm, 1.2 mm, 1 mm, 0.8 mm, 0.5 mm, 0.2 mm, 0, etc.

[0187] By ensuring that the gap between the first edges 2243 of two adjacent negative electrode sheets 224 is less than or equal to 2 mm, the first edges 2243 of the multiple negative electrode sheets 224 of the electrode assembly 22 can be made more uniform, which is beneficial for reducing volume occupation and improving energy density.

[0188] Optionally, 0≤L1≤1mm.

[0189] The distance between the first edges 2243 of two adjacent negative electrode sheets 224 can be: L1 = 1 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, 0.1 mm, 0, etc.

[0190] By ensuring that the gap between the first edges 2243 of two adjacent negative electrode sheets 224 is less than or equal to 1 mm, the first edges 2243 of the multiple negative electrode sheets 224 of the electrode assembly 22 can be made more uniform, which is beneficial for reducing volume occupation and improving energy density.

[0191] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 In some embodiments, along the first direction, the negative electrode sheet 224 has a first edge 2243, and the isolation segment 2251 adjacent to the negative electrode sheet 224 has a second edge 22512 closest to the first edge 2243. The distance between the first edge 2243 and the second edge 22512 is L2, satisfying the following: 0≤L2≤2mm.

[0192] The second edge 22512 is the edge of the isolation segment 2251 along the first direction and is the edge closest to the first edge 2243 of the negative electrode sheet 224. In other words, the first edge 2243 and the second edge 22512 are located on the same side of the positive electrode sheet 226 along the first direction.

[0193] L2 represents the distance between the first edge 2243 and the second edge 22512 along the first direction.

[0194] The distance between the first edge 2243 and the second edge 22512 along the first direction can be: L2 = 2 mm, 1.8 mm, 1.5 mm, 1.2 mm, 1 mm, 0.8 mm, 0.5 mm, 0.2 mm, 0, etc.

[0195] By making the distance between the first edge 2243 and the second edge 22512 less than or equal to 2 mm, the edges of the negative electrode sheet 224 and the isolation segment 2251 can be made more neat, which is beneficial to reducing the volume occupied and improving the energy density.

[0196] Optionally, 0≤L2≤1mm.

[0197] The distance between the first edge 2243 and the second edge 22512 along the first direction can be: L2 = 1 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, 0.1 mm, 0, etc.

[0198] By making the distance between the first edge 2243 and the second edge 22512 less than or equal to 1 mm, the edges of the negative electrode sheet 224 and the isolation segment 2251 can be made more neat, which is beneficial to reducing the volume occupied and improving the energy density.

[0199] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 In some embodiments, along the first direction, the negative electrode body 2242 extends beyond the positive electrode 226 by a dimension L3, satisfying: 3 mm ≤ L3 ≤ 10 mm.

[0200] L3 represents the dimension by which the negative electrode sheet main body 2242 extends beyond the positive electrode sheet 226 along the first direction. It should be noted that the positive electrode sheet 226 includes a positive electrode tab unit 2261 and a positive electrode sheet main body 2262. The positive electrode tab unit 2261 is connected to one side of the positive electrode sheet main body 2262 along the second direction. The negative electrode sheet main body 2242 contains negative electrode active material, while the negative electrode tab unit 2241 does not. L3 represents the dimension by which the negative electrode sheet main body 2242 extends beyond the positive electrode sheet main body 2262 along the first direction.

[0201] The dimension of the negative electrode sheet main body 2242 extending beyond the positive electrode sheet 226 along the first direction may be: L3 = 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, etc.

[0202] When L3 ≥ 3mm, the negative electrode sheet main body 2242 significantly protrudes from the positive electrode sheet 226 along the first direction, which helps meet the overhang design and reduces the risk of lithium plating. When L3 ≤ 10mm, the negative electrode sheet main body 2242 does not protrude excessively from the positive electrode sheet 226 along the first direction, which helps reduce the volume of the negative electrode sheet 224 and improve energy density. Therefore, when 3mm ≤ L3 ≤ 10mm, both the overhang design and energy density can be met.

[0203] Optionally, 5mm≤L3≤8mm.

[0204] The dimension of the negative electrode sheet main body 2242 extending beyond the positive electrode sheet 226 along the first direction may be: L3 = 5mm, 5.2mm, 5.5mm, 5.8mm, 6mm, 6.2mm, 6.5mm, 6.8mm, 7mm, 7.2mm, 7.5mm, 7.8mm, 8mm, etc.

[0205] When L3 ≥ 5mm, the negative electrode sheet main body 2242 protrudes further from the positive electrode sheet 226 along the first direction, which is more conducive to meeting the overhang design and reducing the risk of lithium plating. When L3 ≤ 8mm, the negative electrode sheet main body 2242 does not protrude too much from the positive electrode sheet 226 along the first direction, which helps reduce the volume of the negative electrode sheet 224 and improve energy density. Therefore, when 5mm ≤ L3 ≤ 8mm, both the overhang design and energy density can be met.

[0206] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 , Figure 7 A cross-sectional view of an electrode assembly 22 provided in some embodiments of the present application from a second perspective. In some embodiments, the positive electrode sheet 226 includes a positive electrode tab unit 2261 and a positive electrode sheet body 2262. The positive electrode tab unit 2261 is connected to one side of the positive electrode sheet body 2262 along the second direction. The isolation segment 2251 has a second protruding portion 22513 that extends beyond the positive electrode sheet body 2262 on both sides of the second direction. The second protruding portions 22513 of two adjacent isolation segments 2251 of the positive electrode sheet body 2262 are at least partially fixedly connected to each other to cover at least a portion of the edge of the positive electrode sheet body 2262. The first direction, the second direction, and the stacking direction are perpendicular to each other.

[0207] The positive electrode sheet 226 includes a positive electrode tab unit 2261 and a positive electrode sheet body 2262 . The positive electrode tab unit 2261 is connected to one side of the positive electrode sheet body 2262 along the second direction. The positive electrode sheet body 2262 has positive electrode active material, while the positive electrode tab unit 2261 does not have positive electrode active material.

[0208] The second protruding portion 22513 is the portion of the isolation segment 2251 that protrudes from the positive electrode sheet 226 along the second direction. Both sides of the isolation segment 2251 along the second direction protrude from the positive electrode sheet 226. In other words, the isolation segment 2251 has two second protruding portions 22513, which are spaced apart along the second direction.

[0209] Please refer to Figure 7 , the second direction can be the Z direction shown in the figure.

[0210] Please refer to Figure 7 , along the stacking direction, the second protruding portions 22513 of the two isolation segments 2251 on both sides of the positive electrode sheet 226 are fixedly connected. When connected, the second protruding portion 22513 of one isolation segment 2251 is fixedly connected to the second protruding portion 22513 of the other isolation segment 2251 on the same side as the second protruding portion 22513. Figure 7 , the second protruding portion 22513 located on the left side of one isolation segment 2251 is connected to the second protruding portion 22513 located on the left side of another isolation segment 2251, and the second protruding portion 22513 located on the right side of one isolation segment 2251 is connected to the second protruding portion 22513 located on the right side of another isolation segment 2251.

[0211] By at least partially fixing the second protruding portions 22513 of the two isolation segments 2251 adjacent to the positive electrode sheet main body 2262 to cover at least a portion of the edge of the positive electrode sheet main body 2262, the position of the positive electrode sheet 226 can be limited, thereby facilitating the negative electrode sheet 224 to protrude beyond the positive electrode sheet 226 along the first direction, thereby reducing the risk of lithium plating. Furthermore, the detour growth of dendrites can be prevented, thereby reducing the risk of short circuits and improving the reliability of the battery cell 20.

[0212] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 In some embodiments, two isolation segments 2251 adjacent to the positive electrode sheet 226 are connected to form a closed accommodation space 227 , and the positive electrode sheet body 2262 is accommodated in the accommodation space 227 .

[0213] Along the stacking direction, the two isolation segments 2251 on both sides of the positive electrode sheet 226 are fixedly connected to form a closed accommodation space 227 . The positive electrode sheet body 2262 is accommodated in the accommodation space 227 , and the positive electrode tab unit 2261 extends out of the accommodation space 227 .

[0214] By accommodating the positive electrode sheet body 2262 within the accommodating space 227, the position of the positive electrode sheet body 2262 can be limited, thereby facilitating that the negative electrode sheet 224 extends beyond the positive electrode sheet 226 along the first direction, thereby reducing the risk of lithium plating. Furthermore, this can further prevent the circumferential growth of dendrites, thereby reducing the risk of short circuits and improving the reliability of the battery cell 20.

[0215] Please refer to Figure 5 、 Figure 6 and Figure 7 The present embodiment also provides an electrode assembly 22. The electrode assembly 22 includes a negative electrode sheet 224, a separator 225, and a positive electrode sheet 226. The positive electrode sheet 226, separator 225, and negative electrode sheet 224 are stacked. The negative electrode sheet 224 includes a negative electrode tab unit 2241 and a negative electrode sheet body 2242. The negative electrode tab unit 2241 is connected to one side of the negative electrode sheet body 2242. The thickness of the negative electrode sheet body 2242 is 10 μm to 30 μm. The separator 225 includes an isolation segment 2251 that separates the positive electrode sheet 226 from the negative electrode sheet 224. The isolation segment 2251 has a first protruding portion 22511 that protrudes from the positive electrode sheet 226 on both sides in a first direction. The first protruding portions 22511 of two adjacent isolation segments 2251 of the positive electrode sheet 226 are at least partially fixedly connected to each other to cover at least a portion of the edge of the positive electrode sheet 226. The first direction is perpendicular to the stacking direction of the positive electrode sheet 226 , the separator 225 , and the negative electrode sheet 224 .

[0216] The thickness of the negative electrode sheet main body 2242 of the electrode assembly 22 is 10μm to 30μm, which means that the negative electrode sheet 224 is an ultra-thin negative electrode sheet. The negative electrode sheet 224 is relatively soft, making it difficult for the negative electrode sheet 224 to extend beyond the positive electrode sheet 226 along the first direction when stacked. By at least partially fixing the first extending portion 22511 of the two isolation segments 2251 adjacent to the positive electrode sheet 226 to cover at least a portion of the edge of the positive electrode sheet 226, on the one hand, the position of the positive electrode sheet 226 can be limited, thereby facilitating the negative electrode sheet 224 to extend beyond the positive electrode sheet 226 along the first direction, thereby reducing the risk of lithium plating. On the other hand, it can prevent the growth of dendrites, thereby reducing the risk of short circuits and improving the reliability of the battery cell 20.

[0217] Please refer to Figure 5 、 Figure 6 and Figure 7 In some embodiments, the thickness of the negative electrode sheet main body 2242 is 10 μm to 20 μm.

[0218] The thickness of the negative electrode sheet main body 2242 can be: H = 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, etc.

[0219] The thickness of the negative electrode sheet main body 2242 is thinner and the negative electrode sheet 224 is softer. By at least partially fixing the first protruding portions 22511 of the two isolation segments 2251 adjacent to the positive electrode sheet 226 to cover at least part of the edge of the positive electrode sheet 226, a better effect can be achieved.

[0220] Please refer to Figure 5 、 Figure 6 and Figure 7 In some embodiments, the negative electrode sheet body 2242 includes a negative electrode current collector 22421, and the material of the negative electrode current collector 22421 includes aluminum. The positive electrode sheet 226 includes a positive electrode active material capable of reversibly extracting and inserting sodium ions, and the positive electrode active material includes a sodium-containing compound.

[0221] The negative electrode current collector 22421 is made of aluminum, and the positive electrode active material includes a compound containing sodium. Thus, the battery cell 20 is a sodium ion battery cell.

[0222] The negative electrode current collector 22421 is made of aluminum. The negative electrode sheet 224 is softer. By at least partially fixing the first protruding portions 22511 of the two isolation segments 2251 adjacent to the positive electrode sheet 226 to cover at least part of the edge of the positive electrode sheet 226, a better effect can be achieved.

[0223] Please refer to Figure 5 、 Figure 6 and Figure 7In some embodiments, the electrode assembly 22 includes a plurality of negative electrode sheets 224 and a plurality of positive electrode sheets 226. Along the stacking direction, the plurality of negative electrode sheets 224 are spaced apart, and the positive electrode sheet 226 is disposed between two adjacent negative electrode sheets 224. An isolation segment 2251 separates the positive electrode sheet 226 from the negative electrode sheet 224.

[0224] There are multiple positive electrode sheets 226 and multiple negative electrode sheets 224 , respectively. The multiple positive electrode sheets 226 and the multiple negative electrode sheets 224 are alternately stacked, and an isolation section 2251 is provided between the positive electrode sheet 226 and the negative electrode sheet 224 .

[0225] Multiple negative electrode sheets 224 and multiple positive electrode sheets 226 are stacked, with isolation segments 2251 separating the positive electrode sheets 226 and negative electrode sheets 224. This eliminates the need for bending the negative electrode sheets 224, reducing their footprint and increasing energy density. During manufacturing, a large negative electrode sheet 224 can be continuously bent and stacked, and then cut to form multiple negative electrode sheets 224.

[0226] Please refer to Figure 5 、 Figure 6 and Figure 7 In some embodiments, along the first direction, the negative electrode sheet 224 has a first edge 2243 , and the distance between the first edges 2243 of two adjacent negative electrode sheets 224 is L1 , satisfying: 0≤L1≤2mm.

[0227] The first edge 2243 specifically refers to an edge of the negative electrode sheet 224 along the first direction. L1 represents the distance between the first edges 2243 of two adjacent negative electrode sheets 224. It should be noted that the first edges 2243 of the two negative electrode sheets 224 are located on the same side of the positive electrode sheet 226 along the first direction. The distance between the first edges 2243 of two adjacent negative electrode sheets 224 can be: L1 = 2 mm, 1.8 mm, 1.5 mm, 1.2 mm, 1 mm, 0.8 mm, 0.5 mm, 0.2 mm, 0, etc.

[0228] By ensuring that the gap between the first edges 2243 of two adjacent negative electrode sheets 224 is less than or equal to 2 mm, the first edges 2243 of the multiple negative electrode sheets 224 of the electrode assembly 22 can be made more uniform, which is beneficial for reducing volume occupation and improving energy density.

[0229] Optionally, 0≤L1≤1mm.

[0230] The distance between the first edges 2243 of two adjacent negative electrode sheets 224 can be: L1 = 1 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, 0.1 mm, 0, etc.

[0231] By ensuring that the gap between the first edges 2243 of two adjacent negative electrode sheets 224 is less than or equal to 1 mm, the first edges 2243 of the multiple negative electrode sheets 224 of the electrode assembly 22 can be made more uniform, which is beneficial for reducing volume occupation and improving energy density.

[0232] Please refer to Figure 5 、 Figure 6 and Figure 7 In some embodiments, along the first direction, the negative electrode sheet 224 has a first edge 2243, and the isolation segment 2251 adjacent to the negative electrode sheet 224 has a second edge 22512 closest to the first edge 2243. The distance between the first edge 2243 and the second edge 22512 is L2, satisfying the following: 0≤L2≤2mm.

[0233] Second edge 22512 is the edge of isolation segment 2251 along the first direction, and is the edge closest to first edge 2243 of negative electrode sheet 224. In other words, first edge 2243 and second edge 22512 are located on the same side of positive electrode sheet 226 along the first direction. L2 represents the distance between first edge 2243 along the first direction and second edge 22512. The distance between first edge 2243 and second edge 22512 along the first direction can be: L2 = 2 mm, 1.8 mm, 1.5 mm, 1.2 mm, 1 mm, 0.8 mm, 0.5 mm, 0.2 mm, 0, etc.

[0234] By making the distance between the first edge 2243 and the second edge 22512 less than or equal to 2 mm, the edges of the negative electrode sheet 224 and the isolation segment 2251 can be made more neat, which is beneficial to reducing the volume occupied and improving the energy density.

[0235] Optionally, 0≤L2≤1mm.

[0236] The distance between the first edge 2243 and the second edge 22512 along the first direction can be: L2 = 1 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, 0.1 mm, 0, etc.

[0237] By making the distance between the first edge 2243 and the second edge 22512 less than or equal to 1 mm, the edges of the negative electrode sheet 224 and the isolation segment 2251 can be made more neat, which is beneficial to reducing the volume occupied and improving the energy density.

[0238] Please refer to Figure 5 、 Figure 6 and Figure 7 In some embodiments, along the first direction, the negative electrode body 2242 extends beyond the positive electrode 226 by a dimension L3, satisfying: 3 mm ≤ L3 ≤ 10 mm.

[0239] L3 represents the dimension by which the negative electrode sheet main body 2242 extends beyond the positive electrode sheet 226 along the first direction. It should be noted that the positive electrode sheet 226 includes a positive tab unit 2261 and a positive electrode sheet main body 2262. The positive tab unit 2261 is connected to one side of the positive electrode sheet main body 2262 along the second direction. The negative electrode sheet main body 2242 contains negative active material, while the negative tab unit 2241 does not. L3 represents the dimension by which the negative electrode sheet main body 2242 extends beyond the positive electrode sheet main body 2262 along the first direction. The dimension by which the negative electrode sheet main body 2242 extends beyond the positive electrode sheet main body 2262 along the first direction can be: L3 = 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, etc.

[0240] When L3 ≥ 3mm, the negative electrode sheet main body 2242 significantly protrudes from the positive electrode sheet 226 along the first direction, which helps meet the overhang design and reduces the risk of lithium plating. When L3 ≤ 10mm, the negative electrode sheet main body 2242 does not protrude excessively from the positive electrode sheet 226 along the first direction, which helps reduce the volume of the negative electrode sheet 224 and improve energy density. Therefore, when 3mm ≤ L3 ≤ 10mm, both the overhang design and energy density can be met.

[0241] Optionally, 5mm≤L3≤8mm.

[0242] The dimension of the negative electrode sheet main body 2242 extending beyond the positive electrode sheet 226 along the first direction may be: L3 = 5mm, 5.2mm, 5.5mm, 5.8mm, 6mm, 6.2mm, 6.5mm, 6.8mm, 7mm, 7.2mm, 7.5mm, 7.8mm, 8mm, etc.

[0243] When L3 ≥ 5mm, the negative electrode sheet main body 2242 protrudes further from the positive electrode sheet 226 along the first direction, which is more conducive to meeting the overhang design and reducing the risk of lithium plating. When L3 ≤ 8mm, the negative electrode sheet main body 2242 does not protrude too much from the positive electrode sheet 226 along the first direction, which helps reduce the volume of the negative electrode sheet 224 and improve energy density. Therefore, when 5mm ≤ L3 ≤ 8mm, both the overhang design and energy density can be met.

[0244] Please refer to Figure 5 、 Figure 6 and Figure 7In some embodiments, the positive electrode sheet 226 includes a positive electrode tab unit 2261 and a positive electrode sheet body 2262. The positive electrode tab unit 2261 is connected to one side of the positive electrode sheet body 2262 along the second direction. The isolation segment 2251 has a second protruding portion 22513 that protrudes from the positive electrode sheet body 2262 on both sides of the second direction. The second protruding portions 22513 of two adjacent isolation segments 2251 of the positive electrode sheet body 2262 are at least partially fixedly connected to each other to cover at least a portion of the edge of the positive electrode sheet body 2262. The first direction, the second direction, and the stacking direction are perpendicular to each other.

[0245] The positive electrode sheet 226 includes a positive electrode tab unit 2261 and a positive electrode sheet body 2262. The positive electrode tab unit 2261 is connected to one side of the positive electrode sheet body 2262 along the second direction. The positive electrode sheet body 2262 contains positive electrode active material, while the positive electrode tab unit 2261 does not contain positive electrode active material. The second protruding portion 22513 is the portion of the isolation segment 2251 that protrudes from the positive electrode sheet 226 along the second direction. Both sides of the isolation segment 2251 along the second direction protrude from the positive electrode sheet 226. In other words, the isolation segment 2251 has two second protruding portions 22513, and the two second protruding portions 22513 are spaced apart along the second direction. Please refer to Figure 7 , the second direction can be the Z direction shown in the figure. Please refer to Figure 7 , along the stacking direction, the second protruding portions 22513 of the two isolation segments 2251 on both sides of the positive electrode sheet 226 are fixedly connected. When connected, the second protruding portion 22513 of one isolation segment 2251 is fixedly connected to the second protruding portion 22513 of the other isolation segment 2251 on the same side as the second protruding portion 22513. Figure 7 , the second protruding portion 22513 located on the left side of one isolation segment 2251 is connected to the second protruding portion 22513 located on the left side of another isolation segment 2251, and the second protruding portion 22513 located on the right side of one isolation segment 2251 is connected to the second protruding portion 22513 located on the right side of another isolation segment 2251.

[0246] By at least partially fixing the second protruding portions 22513 of the two isolation segments 2251 adjacent to the positive electrode sheet main body 2262 to cover at least a portion of the edge of the positive electrode sheet main body 2262, the position of the positive electrode sheet 226 can be limited, thereby facilitating the negative electrode sheet 224 to protrude beyond the positive electrode sheet 226 along the first direction, thereby reducing the risk of lithium plating. Furthermore, the detour growth of dendrites can be prevented, thereby reducing the risk of short circuits and improving the reliability of the battery cell 20.

[0247] Please refer to Figure 5 、 Figure 6 and Figure 7In some embodiments, the two isolation segments 2251 adjacent to the positive electrode sheet 226 are connected to form a closed accommodation space 227, and the positive electrode sheet body 2262 is accommodated in the accommodation space 227. Along the stacking direction, the two isolation segments 2251 located on both sides of the positive electrode sheet 226 are fixedly connected to form a closed accommodation space 227, the positive electrode sheet body 2262 is accommodated in the accommodation space 227, and the positive electrode ear unit 2261 extends out of the accommodation space 227. By accommodating the positive electrode sheet body 2262 in the accommodation space 227, on the one hand, the position of the positive electrode sheet body 2262 can be limited, which is conducive to making the negative electrode sheet 224 extend beyond the positive electrode sheet 226 along the first direction, reducing the risk of lithium plating. On the other hand, it can further prevent the dendrite from growing in a roundabout way, thereby reducing the risk of short circuit and improving the reliability of the battery cell 20.

[0248] Please refer to Figure 8 , Figure 8 This is a schematic block diagram of an electrode assembly manufacturing method 30 provided in some embodiments of the present application. The present application also provides an electrode assembly manufacturing method 30, which includes:

[0249] Step S100: providing a positive electrode sheet 226, a separator 225, and a negative electrode sheet 224. The negative electrode sheet 224 includes a negative electrode tab unit 2241 and a negative electrode sheet body 2242. The negative electrode tab unit 2241 is connected to one side of the negative electrode sheet body 2242. The thickness of the negative electrode sheet body 2242 is 10 μm to 30 μm.

[0250] Step S200: The positive electrode sheet 226, the separator 225, and the negative electrode sheet 224 are stacked. The separator 225 has an isolation segment 2251 that separates the positive electrode sheet 226 from the negative electrode sheet 224. The isolation segment 2251 has a first protruding portion 22511 that protrudes from the positive electrode sheet 226 on both sides in a first direction. The first direction is perpendicular to the stacking direction of the positive electrode sheet 226, the separator 225, and the negative electrode sheet 224.

[0251] Step S300 : at least partially fixing and connecting the first protruding portions 22511 of the two isolation segments 2251 adjacent to the positive electrode sheet 226 to cover at least a portion of the edge of the positive electrode sheet 226 .

[0252] By at least partially fixing the first protruding portions 22511 of the two isolation segments 2251 adjacent to the positive electrode sheet 226 to cover at least a portion of the edge of the positive electrode sheet 226, the position of the positive electrode sheet 226 can be limited, thereby facilitating the negative electrode sheet 224 to protrude beyond the positive electrode sheet 226 along the first direction, thereby reducing the risk of lithium deposition. Furthermore, the circumferential growth of dendrites can be prevented, thereby reducing the risk of short circuits and improving the reliability of the battery cell 20.

[0253] In step S100 , the thickness of the negative electrode sheet main body 2242 is 10 μm to 20 μm.

[0254] In step S100 , the thickness of the negative electrode sheet main body 2242 may be: H=10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, etc.

[0255] The thickness of the negative electrode sheet main body 2242 is thinner and the negative electrode sheet 224 is softer. By at least partially fixing the first protruding portions 22511 of the two isolation segments 2251 adjacent to the positive electrode sheet 226 to cover at least part of the edge of the positive electrode sheet 226, a better effect can be achieved.

[0256] In some embodiments, in step S200 , the difference between the maximum thickness of the negative electrode sheet main body 2242 and the minimum thickness of the negative electrode sheet 224 is less than or equal to 2 μm.

[0257] The difference between the maximum thickness of the negative electrode sheet 2242 and the minimum thickness of the negative electrode sheet 224 is less than or equal to 2 μm, that is, the thickness of each position of the negative electrode sheet 2242 is roughly the same. In other words, there is no need to make marks on the negative electrode sheet 2242.

[0258] Optionally, the thickness of each position of the negative electrode sheet main body 2242 is equal.

[0259] The thickness of each position of the negative electrode sheet main body 2242 is equal, and there is no need to make marks on the negative electrode sheet main body 2242.

[0260] Please refer to Figure 9 , Figure 9 This is a schematic block diagram of an electrode assembly manufacturing method 30 provided in some other embodiments of the present application. In some other embodiments, step S200 includes:

[0261] Step S210: The positive electrode sheet 226, the separator 225, and the negative electrode sheet 224 are formed into a composite electrode sheet 228. The composite electrode sheet 228 includes a plurality of positive electrode sheets 226, which are alternately arranged on both sides of the negative electrode sheet 224. Along the length direction of the composite electrode sheet 228, the portion of the composite electrode sheet 228 located between two adjacent positive electrode sheets 226 is a bent section 2281.

[0262] Step S220 : bending the bent section 2281 to stack the positive electrode sheet 226 , the separator 225 , and the negative electrode sheet 224 .

[0263] Please refer to Figure 10 , Figure 10 A schematic structural diagram of the composite pole piece 228 provided in some embodiments of the present application. Figure 10The composite electrode 228 comprises a negative electrode 224 and a plurality of positive electrode 226 , which are alternately arranged on both sides of the negative electrode 224 . A separator 225 is further arranged between the positive electrode 226 and the negative electrode 224 .

[0264] Optionally, the composite electrode sheet 228 includes two separators 225 , and the two separators 225 are respectively disposed on both sides of the negative electrode sheet 224 .

[0265] Please refer to Figure 10 The length direction of the composite pole piece 228 is the direction A shown in the figure.

[0266] The portion of the composite electrode 228 located between two adjacent positive electrode sheets 226 is a bent section 2281 . Since there is no positive electrode sheet 226 in the bent section 2281 and the negative electrode sheet 224 is an ultra-thin negative electrode sheet, the bent section 2281 is relatively weak and easily bent.

[0267] Please refer to Figure 11 , Figure 11 A cross-sectional view of a product after step S220 is provided in some embodiments of the present application. Figure 11 The product after step S220 is shown. At this time, there are multiple positive electrode sheets 226, and the negative electrode sheet 224 is folded to form multiple stacked folded segments, with one positive electrode sheet 226 sandwiched between adjacent folded segments.

[0268] By first making the composite electrode 228, the bending section 2281 of the composite electrode 228 is relatively weak, and the bending section 2281 can be bent to stack the positive electrode 226, the isolation member 225 and the negative electrode 224, making the manufacturing simple and convenient, and helping to make the negative electrode 224 extend beyond the positive electrode 226 along the first direction, thereby reducing the risk of lithium plating.

[0269] Please refer to Figure 12 , Figure 12 This is a schematic block diagram of an electrode assembly manufacturing method 30 provided in some other embodiments of the present application. In some other embodiments, after step S300, the electrode assembly manufacturing method 30 further includes:

[0270] Step S400 : cutting the negative electrode sheet 224 and the separator 225 to remove the portion of the negative electrode sheet 224 and the separator 225 located at the bent section 2281 of the composite electrode sheet 228 .

[0271] Please refer to Figure 5 , Figure 5 4 is a cross-sectional view of the product after step S400 . In step S400 , the negative electrode sheet 224 and the portion of the separator 225 located at the bent section 2281 of the composite electrode sheet 228 are removed by cutting, thereby reshaping the electrode assembly 22 .

[0272] It should be noted that, during cutting, the first protruding portions 22511 of the two isolation segments 2251 adjacent to the positive electrode sheet 226 need to be kept fixedly connected.

[0273] Because the negative electrode sheet 224 is relatively soft, the bent section 2281 of the composite electrode sheet 228 is prone to a large curvature. By trimming the negative electrode sheet 224 and separator 225, and removing the portion of the negative electrode sheet 224 and separator 225 located at the bent section 2281 of the composite electrode sheet 228, the electrode assembly 22 is reshaped. This, on the one hand, helps to smooth the interface of the electrode assembly 22, reducing the gap between the positive and negative electrode sheets, thereby shortening the ion path. On the other hand, it helps to reduce the volume occupied and improve the energy density.

[0274] In some embodiments, in step S400 , along the first direction, the negative electrode sheet 224 has a first edge 2243 , and the distance between the first edges 2243 of two adjacent negative electrode sheets 224 is controlled within 2 mm.

[0275] The distance between the first edges 2243 of two adjacent negative electrode sheets 224 is controlled within 2 mm, so that 0≤L1≤2 mm.

[0276] By ensuring that the gap between the first edges 2243 of two adjacent negative electrode sheets 224 is less than or equal to 2 mm, the cut surface is more neat. On the one hand, the gap between the positive and negative electrode sheets is smaller, which helps shorten the ion path. On the other hand, it helps reduce the volume occupied and improve the energy density.

[0277] Optionally, in step S400 , along the first direction, the negative electrode sheet 224 has a first edge 2243 , and the distance between the first edges 2243 of two adjacent negative electrode sheets 224 is controlled within 1 mm.

[0278] The distance between the first edges 2243 of two adjacent negative electrode sheets 224 is controlled within 1 mm, so that 0≤L1≤1 mm.

[0279] By ensuring that the gap between the first edges 2243 of two adjacent negative electrode sheets 224 is less than or equal to 1 mm, the cut surface is made more neat. On the one hand, the gap between the positive and negative electrode sheets is smaller, which helps shorten the ion path. On the other hand, it helps reduce the volume occupied and improve the energy density.

[0280] In some embodiments, in step S400 , along the first direction, the distance between the cutting position of the negative electrode sheet 224 and the separator 225 and the positive electrode sheet 226 is controlled to be within 3 mm to 10 mm.

[0281] The distance between the cutting position of the negative electrode sheet 224 and the separator 225 and the positive electrode sheet 226 is controlled within 3 mm to 10 mm, so that 3 mm ≤ L3 ≤ 10 mm.

[0282] When the distance between the cutting position of the negative electrode sheet 224 and the separator 225 and the positive electrode sheet 226 is greater than or equal to 3mm, the negative electrode sheet 224 is larger than the positive electrode sheet 226 along the first direction, which is conducive to meeting the overhang design and reducing the risk of lithium plating. When the distance between the cutting position of the negative electrode sheet 224 and the separator 225 and the positive electrode sheet 226 is less than or equal to 10mm, the negative electrode sheet 224 is not too large in the first direction, which is conducive to reducing the volume of the negative electrode sheet 224 and improving the energy density. Therefore, when the distance between the cutting position of the negative electrode sheet 224 and the separator 225 and the positive electrode sheet 226 is within 3mm to 10mm, it can both meet the overhang design and improve the energy density.

[0283] Optionally, in step S400 , along the first direction, the distance between the cutting position of the negative electrode sheet 224 and the separator 225 and the positive electrode sheet 226 is controlled within a range of 5 mm to 8 mm.

[0284] The distance between the cutting position of the negative electrode sheet 224 and the separator 225 and the positive electrode sheet 226 is controlled within 5 mm to 8 mm, so that 5 mm ≤ L3 ≤ 8 mm.

[0285] When the distance between the cutting position of the negative electrode sheet 224 and the separator 225 and the positive electrode sheet 226 is greater than or equal to 5mm, the negative electrode sheet 224 is larger than the positive electrode sheet 226 along the first direction, which is conducive to meeting the overhang design and reducing the risk of lithium plating. When the distance between the cutting position of the negative electrode sheet 224 and the separator 225 and the positive electrode sheet 226 is less than or equal to 8mm, the negative electrode sheet 224 is not too large in the first direction, which is conducive to reducing the volume of the negative electrode sheet 224 and improving the energy density. Therefore, when the distance between the cutting position of the negative electrode sheet 224 and the separator 225 and the positive electrode sheet 226 is within 5mm to 8mm, it can both meet the overhang design and improve the energy density.

[0286] In some embodiments, in step S400 , the distance between the first edge 2243 of the cut negative electrode sheet 224 and the second edge 22512 of the isolation segment 2251 adjacent to the negative electrode sheet 224 , closest to the first edge 2243 , is controlled within 2 mm along the first direction.

[0287] The distance between the first edge 2243 of the cut negative electrode sheet 224 and the second edge 22512 of the isolation segment 2251 adjacent to the negative electrode sheet 224 and closest to the first edge 2243 is controlled within 2 mm, so that 0≤L2≤2 mm.

[0288] By making the distance between the first edge 2243 and the second edge 22512 less than or equal to 2 mm, the edges of the negative electrode sheet 224 and the isolation segment 2251 can be made more neat, which is beneficial to reducing the volume occupied and improving the energy density.

[0289] Optionally, in step S400 , along the first direction, the distance between the first edge 2243 of the cut negative electrode sheet 224 and the second edge 22512 of the separator 225 closest to the first edge 2243 is controlled to be within 1 mm.

[0290] The distance between the first edge 2243 of the cut negative electrode sheet 224 and the second edge 22512 of the isolation segment 2251 adjacent to the negative electrode sheet 224 and closest to the first edge 2243 is controlled within 1 mm, so that 0≤L2≤1 mm.

[0291] By making the distance between the first edge 2243 and the second edge 22512 less than or equal to 1 mm, the edges of the negative electrode sheet 224 and the isolation segment 2251 can be made more neat, which is beneficial to reducing the volume occupied and improving the energy density.

[0292] Please refer to Figure 13 , Figure 13 This is a schematic block diagram of an electrode assembly manufacturing method 30 provided in some embodiments of the present application. In some embodiments, step S300 includes:

[0293] Step S310 : at least partially fixing and connecting the first protruding portions 22511 of the two isolation segments 2251 adjacent to the positive electrode sheet 226 by hot pressing.

[0294] The first protruding portions 22511 of the two isolation segments 2251 are at least partially fixedly connected by hot pressing. This facilitates manufacturing and allows simultaneous connection of the isolation segments 2251 on both sides of each positive electrode sheet 226. Furthermore, hot pressing is less likely to damage the positive electrode sheet 226 and the negative electrode sheet 224, thereby improving the reliability of the electrode assembly 22.

[0295] The embodiment of the present application further provides a battery device 100 , which includes the above-mentioned battery cell 20 .

[0296] An embodiment of the present application further provides an electrical device, which includes the above-mentioned battery cell 20, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0297] According to some embodiments of this application, please refer to Figures 3 to 13 .

[0298] The embodiment of the present application provides a battery cell 20, which includes a housing 21 and an electrode assembly 22. The electrode assembly 22 is housed within the housing 21. The electrode assembly 22 includes a negative electrode sheet 224, a separator 225, and a positive electrode sheet 226. The positive electrode sheet 226, separator 225, and negative electrode sheet 224 are stacked. The negative electrode sheet 224 includes a negative electrode tab unit 2241 and a negative electrode sheet body 2242. The negative electrode tab unit 2241 is connected to one side of the negative electrode sheet body 2242. The thickness of the negative electrode sheet body 2242 is 10 μm to 30 μm. The separator 225 includes an isolation segment 2251 that separates the positive electrode sheet 226 from the negative electrode sheet 224. The isolation segment 2251 includes a first protruding portion 22511 that protrudes beyond the positive electrode sheet 226 on both sides in a first direction. The first protruding portions 22511 of two adjacent isolation segments 2251 of the positive electrode sheet 226 are at least partially fixedly connected to each other, thereby covering at least a portion of the edge of the positive electrode sheet 226. The first direction is perpendicular to the stacking direction of the positive electrode sheet 226, the separator 225, and the negative electrode sheet 224. The thickness of the negative electrode sheet main body 2242 of the battery cell 20 is 10 μm to 30 μm, meaning that the negative electrode sheet 224 is ultra-thin and relatively soft, making it difficult for the negative electrode sheet 224 to protrude beyond the positive electrode sheet 226 in the first direction during stacking. By at least partially fixing the first protruding portions 22511 of the two isolation segments 2251 adjacent to the positive electrode sheet 226 to cover at least a portion of the edge of the positive electrode sheet 226, the position of the positive electrode sheet 226 can be limited, thereby facilitating the negative electrode sheet 224 to protrude beyond the positive electrode sheet 226 along the first direction, thereby reducing the risk of lithium deposition. Furthermore, the circumferential growth of dendrites can be prevented, thereby reducing the risk of short circuits and improving the reliability of the battery cell 20.

[0299] The thickness of the negative electrode sheet body 2242 is 10 μm to 20 μm. The thinner the negative electrode sheet body 2242 is, the softer the negative electrode sheet 224 is. By at least partially fixing the first protruding portions 22511 of the two adjacent isolation segments 2251 to the positive electrode sheet 226, thereby covering at least a portion of the edge of the positive electrode sheet 226, a better effect can be achieved.

[0300] The negative electrode sheet body 2242 includes a negative current collector 22421 made of aluminum. The positive electrode sheet 226 includes a positive active material capable of reversibly extracting and inserting sodium ions, comprising a sodium-containing compound. The negative current collector 22421 is made of aluminum. Since the negative electrode sheet 224 is relatively soft, better performance can be achieved by at least partially securing the first protruding portions 22511 of the two adjacent separator segments 2251 to each other, thereby covering at least a portion of the edge of the positive electrode sheet 226.

[0301] The positive electrode sheet 226 includes a positive electrode tab unit 2261 and a positive electrode sheet body 2262. The positive electrode tab unit 2261 is connected to one side of the positive electrode sheet body 2262 along the second direction. The isolation segment 2251 has a second protruding portion 22513 that protrudes from the positive electrode sheet body 2262 on both sides of the second direction. The second protruding portions 22513 of two isolation segments 2251 adjacent to the positive electrode sheet body 2262 are at least partially fixedly connected to at least partially cover the edge of the positive electrode sheet body 2262. The first direction, the second direction, and the stacking direction are perpendicular to each other. By at least partially fixing the second protruding portions 22513 of two isolation segments 2251 adjacent to the positive electrode sheet body 2262 to at least partially cover the edge of the positive electrode sheet body 2262, the position of the positive electrode sheet 226 can be limited, thereby facilitating the negative electrode sheet 224 to protrude from the positive electrode sheet 226 along the first direction, thereby reducing the risk of lithium plating. On the other hand, it can prevent dendrites from growing in a circumferential direction, thereby reducing the risk of short circuit and improving the reliability of the battery cell 20 .

[0302] The two isolation segments 2251 adjacent to the positive electrode sheet 226 are connected to form a closed accommodation space 227, in which the positive electrode sheet body 2262 is accommodated. Accommodating the positive electrode sheet body 2262 within the accommodation space 227 can, on the one hand, limit the position of the positive electrode sheet body 2262, thereby facilitating that the negative electrode sheet 224 extends beyond the positive electrode sheet 226 along the first direction, reducing the risk of lithium plating. On the other hand, this can further prevent the circumferential growth of dendrites, thereby reducing the risk of short circuits and improving the reliability of the battery cell 20.

[0303] The embodiment of the present application also provides an electrode assembly manufacturing method 30, which includes: step S100: providing a positive electrode sheet 226, a separator 225 and a negative electrode sheet 224, wherein the negative electrode sheet 224 includes a negative electrode ear unit 2241 and a negative electrode sheet body 2242, wherein the negative electrode ear unit 2241 is connected to one side of the negative electrode sheet body 2242, and the thickness of the negative electrode sheet body 2242 is 10 μm to 30 μm; step S200: layering the positive electrode sheet 226, the separator 225 and the negative electrode sheet 224 The insulating member 225 is stacked, and the insulating member 225 has an insulating segment 2251 for separating the positive electrode sheet 226 and the negative electrode sheet 224. The insulating segment 2251 has a first protruding portion 22511 that protrudes from the positive electrode sheet 226 on both sides in a first direction. The first direction is perpendicular to the stacking direction of the positive electrode sheet 226, the insulating member 225 and the negative electrode sheet 224. Step S300: at least partially fix the first protruding portions 22511 of the two insulating segments 2251 adjacent to the positive electrode sheet 226 to cover at least part of the edge of the positive electrode sheet 226.

[0304] The thickness of the negative electrode sheet main body 2242 is equal at all locations. The thickness of the negative electrode sheet main body 2242 is equal at all locations, and there is no need to make marks on the negative electrode sheet main body 2242.

[0305] Step S200 includes: Step S210: The positive electrode sheet 226, the separator 225 and the negative electrode sheet 224 are made into a composite electrode sheet 228, and the composite electrode sheet 228 includes multiple positive electrode sheets 226, and the multiple positive electrode sheets 226 are alternately arranged on both sides of the negative electrode sheet 224. Along the length direction of the composite electrode sheet 228, the part of the composite electrode sheet 228 located between two adjacent positive electrode sheets 226 is a bending section 2281; Step S220: Bend the bending section 2281 so that the positive electrode sheet 226, the separator 225 and the negative electrode sheet 224 are stacked. By first making the composite electrode 228, the bending section 2281 of the composite electrode 228 is relatively weak, and the bending section 2281 can be bent to stack the positive electrode 226, the isolation member 225 and the negative electrode 224, making the manufacturing simple and convenient, and helping to make the negative electrode 224 extend beyond the positive electrode 226 along the first direction, thereby reducing the risk of lithium plating.

[0306] After step S300 , the electrode assembly manufacturing method 30 further includes: step S400 : cutting the negative electrode sheet 224 and separator 225 to remove the portion of the negative electrode sheet 224 and separator 225 located at the bent section 2281 of the composite electrode sheet 228 . Because the negative electrode sheet 224 is relatively soft, the bent section 2281 of the composite electrode sheet 228 tends to have a large curvature. Cutting the negative electrode sheet 224 and separator 225 to remove the portion of the negative electrode sheet 224 and separator 225 located at the bent section 2281 of the composite electrode sheet 228 reshapes the electrode assembly 22 . This, on the one hand, helps to smooth the interface of the electrode assembly 22 , reducing the gap between the positive and negative electrode sheets, thereby shortening the ion path. On the other hand, it helps to reduce the volume occupied and improve energy density.

[0307] Step S300 includes: Step S310: At least partially securing the first protruding portions 22511 of two separators 2251 adjacent to the positive electrode sheet 226 by hot pressing. At least partially securing the first protruding portions 22511 of the two separators 2251 by hot pressing facilitates manufacturing, enabling simultaneous connection of the separators 2251 on both sides of each positive electrode sheet 226. Furthermore, hot pressing minimizes damage to the positive electrode sheet 226 and the negative electrode sheet 224, thereby improving the reliability of the electrode assembly 22.

[0308] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. 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: include: shell; an electrode assembly housed in the housing, the electrode assembly comprising a negative electrode sheet, a separator, and a positive electrode sheet, the positive electrode sheet, the separator, and the negative electrode sheet being stacked, the negative electrode sheet comprising a negative electrode tab unit and a negative electrode sheet body, the negative electrode tab unit being connected to one side of the negative electrode sheet body, and the thickness of the negative electrode sheet body being 10 μm to 30 μm; The separator has an isolation segment that separates the positive electrode sheet and the negative electrode sheet, and the isolation segment has a first protruding portion that protrudes beyond the positive electrode sheet on both sides of the first direction. The first protruding portions of the two isolation segments adjacent to the positive electrode sheet are at least partially fixedly connected to cover at least a portion of the edge of the positive electrode sheet, and the first direction is perpendicular to the stacking direction of the positive electrode sheet, the separator and the negative electrode sheet.

2. The battery cell according to claim 1, characterized in that: The thickness of the negative electrode sheet body is 10 μm to 20 μm.

3. The battery cell according to claim 1, characterized in that: The negative electrode sheet main body includes a negative electrode current collector, and the material of the negative electrode current collector includes aluminum; The positive electrode sheet includes a positive electrode active material capable of reversibly extracting and inserting sodium ions, and the positive electrode active material includes a sodium-containing compound.

4. The battery cell according to claim 1, characterized in that: The electrode assembly includes a plurality of negative electrode sheets and a plurality of positive electrode sheets. Along the stacking direction, the plurality of negative electrode sheets are arranged at intervals, and the positive electrode sheet is arranged between two adjacent negative electrode sheets. The isolation segment separates the positive electrode sheet and the negative electrode sheet.

5. The battery cell according to claim 4, characterized in that: Along the first direction, the negative electrode sheet has a first edge, and the distance between the first edges of two adjacent negative electrode sheets is L1, which satisfies: 0≤L1≤2mm.

6. The battery cell according to claim 5, characterized in that: 0≤L1≤1mm.

7. The battery cell according to claim 4, characterized in that: Along a first direction, the negative electrode sheet has a first edge, and the isolation segment adjacent to the negative electrode sheet has a second edge closest to the first edge. The distance between the first edge and the second edge is L2, satisfying: 0≤L2≤2mm.

8. The battery cell according to claim 7, characterized in that: 0≤L2≤1mm.

9. The battery cell according to claim 4, characterized in that: Along the first direction, the negative electrode sheet main body extends beyond the positive electrode sheet by a dimension L3, which satisfies: 3mm≤L3≤10mm.

10. The battery cell according to claim 9, characterized in that: 5mm≤L3≤8mm.

11. The battery cell according to any one of claims 1 to 10, characterized in that: The positive electrode sheet includes a positive electrode tab unit and a positive electrode sheet body, wherein the positive electrode tab unit is connected to one side of the positive electrode sheet body along the second direction; The isolation segment has a second protruding portion that protrudes from the positive electrode sheet body on both sides of the second direction, and the second protruding portions of the two isolation segments adjacent to the positive electrode sheet body are at least partially fixedly connected to cover at least part of the edge of the positive electrode sheet body, and the first direction, the second direction and the stacking direction are perpendicular to each other.

12. The battery cell according to claim 11, characterized in that: The two isolation segments adjacent to the positive electrode sheet are connected to form a closed accommodation space, and the positive electrode sheet body is accommodated in the accommodation space.

13. An electrode assembly, characterized in that: The invention comprises a negative electrode sheet, a separator and a positive electrode sheet, wherein the positive electrode sheet, the separator and the negative electrode sheet are stacked, the negative electrode sheet comprises a negative electrode tab unit and a negative electrode sheet body, the negative electrode tab unit is connected to one side of the negative electrode sheet body, and the thickness of the negative electrode sheet body is 10 μm to 30 μm; The separator has an isolation segment that separates the positive electrode sheet and the negative electrode sheet, and the isolation segment has a first protruding portion that protrudes beyond the positive electrode sheet on both sides of the first direction. The first protruding portions of the two isolation segments adjacent to the positive electrode sheet are at least partially fixedly connected to cover at least a portion of the edge of the positive electrode sheet, and the first direction is perpendicular to the stacking direction of the positive electrode sheet, the separator and the negative electrode sheet.

14. The electrode assembly according to claim 13, characterized in that: The thickness of the negative electrode sheet body is 10 μm to 20 μm.

15. The electrode assembly according to claim 13, characterized in that: The negative electrode sheet main body includes a negative electrode current collector, and the material of the negative electrode current collector includes aluminum; The positive electrode sheet includes a positive electrode active material capable of reversibly extracting and inserting sodium ions, and the positive electrode active material includes a sodium-containing compound.

16. The electrode assembly according to any one of claims 13 to 15, characterized in that: The electrode assembly includes a plurality of negative electrode sheets and a plurality of positive electrode sheets. Along the stacking direction, the plurality of negative electrode sheets are arranged at intervals, and the positive electrode sheet is arranged between two adjacent negative electrode sheets. The isolation segment separates the positive electrode sheet and the negative electrode sheet.

17. The electrode assembly according to claim 16, characterized in that: Along the first direction, the negative electrode sheet has a first edge, and the distance between the first edges of two adjacent negative electrode sheets is L1, which satisfies: 0≤L1≤2mm.

18. The electrode assembly according to claim 17, characterized in that: 0≤L1≤1mm.

19. The electrode assembly according to claim 16, characterized in that: Along a first direction, the negative electrode sheet has a first edge, and the isolation segment adjacent to the negative electrode sheet has a second edge closest to the first edge. The distance between the first edge and the second edge is L2, satisfying: 0≤L2≤2mm.

20. The electrode assembly according to claim 19, characterized in that: 0≤L2≤1mm.

21. The electrode assembly according to claim 16, wherein: Along the first direction, the negative electrode sheet main body extends beyond the positive electrode sheet by a dimension L3, which satisfies: 3mm≤L3≤10mm.

22. The electrode assembly according to claim 21, characterized in that 5mm≤L3≤8mm.

23. A battery device, characterized in that: The invention comprises a battery cell according to any one of claims 1 to 12.

24. An electrical device, characterized in that: The battery cell comprises the battery cell according to any one of claims 1 to 12, and the battery cell is used to provide electrical energy to the electrical device.

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