Battery cell, battery device, and electric device

Abstract

The application discloses a battery monomer, a battery device and a power utilization device. The battery monomer comprises an electrode pole piece, the electrode pole piece comprises a current collector, the current collector comprises a composite base film and a conductive layer located on at least one side of the composite base film; the tensile strength of the composite base film is 320 MPa-450 MPa; and the sum of the relative mass contents of N, O, P and S elements on the surface of the composite base film is less than or equal to 1%. The battery monomer provided by the application has improved cycle performance.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a battery cell, a battery device, and an electrical device. Background Technology

[0002] Batteries are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric car toys, electric toy ships, electric toy airplanes, and power tools.

[0003] In the development of battery cells, improving the cycle performance of battery cells is one of the urgent problems to be solved. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a battery cell, a battery device, and an electrical device.

[0005] In a first aspect, embodiments of this application provide a battery cell. The battery cell includes an electrode sheet, the electrode sheet includes a current collector, the current collector includes a composite base film and a conductive layer located on at least one side of the composite base film; the tensile strength of the composite base film is 320MPa-450MPa; the sum of the relative mass contents of N, O, P and S elements on the surface of the composite base film is less than or equal to 1%.

[0006] According to the embodiments of this application, limiting the tensile strength of the composite base film within the aforementioned range is beneficial for the current collector to have higher mechanical strength, which can reduce the risk of deformation or even breakage of the current collector caused by the expansion of the active material layer. Furthermore, since the active groups in the polymer current collector mainly include active elements such as N, O, P, and S, by keeping the mass content of active elements N, O, P, and S on the surface of the composite base film within a lower range, the content of active groups on the surface of the composite base film can be reduced. This reduces the reaction consumption of active groups on the active materials in the battery cell, thereby reducing the penetration and corrosion of the first base film by the active material and electrolyte, allowing the current collector to maintain high strength during the charge-discharge cycle of the battery cell.

[0007] In some embodiments, the composite base film includes a first base film and a second base film located on both sides of the first base film. The second base film is located between the first base film and the conductive layer. The tensile strength of the first base film is 350MPa-600MPa. The sum of the relative mass contents of N, O, P and S elements on the surface of the second base film away from the first base film is less than or equal to 1%.

[0008] In some embodiments, the first base film material includes one or more of polyimide, polyethylene terephthalate, polyethylene, polypropylene, polystyrene, and polycarbonate.

[0009] In some embodiments, the tensile strength of the second base film is 100MPa-300MPa.

[0010] In some embodiments, the melting point of the second base film is 150°C-200°C.

[0011] In some embodiments, the material of the second base film includes one or more of polypropylene, polyethylene, and polystyrene, and the material of the second base film is different from the material of the first base film.

[0012] In some embodiments, the thickness of the first base film accounts for 50%-80% of the total thickness of the composite base film.

[0013] In some embodiments, the thickness of the first base film is 2 μm-6 μm.

[0014] In some embodiments, the thickness of the second base film is 0.5 μm-3 μm.

[0015] In some embodiments, the conductive layer comprises one or more of Cu, Ag, Au, Ni, Al, and their respective alloys.

[0016] In some embodiments, the thickness of the conductive layer is 0.5 μm-1.5 μm.

[0017] In some embodiments, the current collector further includes a functional layer located between the composite base film and the conductive layer, the functional layer comprising metal particles or a binder.

[0018] In some embodiments, the metal particles include one or more of Ni, Fe, Cr, Co, and alloys of the aforementioned metal elements.

[0019] In some embodiments, the adhesive comprises one or more of polyacrylates and their modified polymers.

[0020] In some embodiments, the thickness of the functional layer is 50nm-500nm.

[0021] In some embodiments, the sheet resistance of the current collector is 10Ω / sq-35mΩ / sq.

[0022] In some embodiments, the electrode plates include one or both of positive and negative electrode plates.

[0023] In some embodiments, the electrode sheet is a negative electrode sheet, the negative electrode sheet includes a negative electrode film layer located on at least one side surface of the current collector, the negative electrode film layer including a negative electrode active material.

[0024] In some embodiments, the negative electrode active material includes one or more of Li, Sn, Zn, carbon-based materials, and silicon-based materials.

[0025] In some embodiments, the silicon-based material includes silicon-carbon composite materials.

[0026] Secondly, embodiments of this application provide a battery device, including a single battery cell from the first aspect of this application.

[0027] Thirdly, embodiments of this application provide an electrical device, including a battery cell from the first aspect of this application or a battery device from the second aspect of this application. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0029] Figure 1 The diagram shows the structural features of a vehicle provided in some embodiments of this application.

[0030] Figure 2 This is an exploded schematic diagram of a battery provided for some embodiments of this application.

[0031] Figure 3 for Figure 2 The diagram shows an exploded view of the battery module.

[0032] The accompanying drawings are not necessarily drawn to scale.

[0033] The reference numerals in the attached drawings are explained as follows: 1. Vehicle; 2. Battery unit; 3. Controller; 4. Motor; 5. Housing; 5a. First housing section; 5b. Second housing section; 5c. Reception space; 6. Battery module; 7. Battery cell. Detailed Implementation

[0034] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the battery cell, battery device, and power-consuming device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0035] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0036] Unless otherwise specified, all embodiments and optional embodiments of this application may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of this application.

[0037] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions, and such technical solutions shall be deemed to be included in the disclosure of this application.

[0038] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0039] Unless otherwise specified, in this application, the terms "first," "second," etc., are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0040] In this application, the terms "multiple" or "various" refer to two or more kinds.

[0041] In the description of the embodiments of this application, unless otherwise specified, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0042] Unless otherwise stated, the terms used in this application have the common meanings as commonly understood by those skilled in the art.

[0043] Unless otherwise stated, the values ​​of the parameters mentioned in this application can be determined using various testing methods commonly used in the art, for example, according to the testing methods given in the embodiments of this application. Unless otherwise stated, the test temperature for each parameter is 25°C.

[0044] The battery device mentioned in the embodiments of this application can be a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application can include battery cells, battery modules, or battery packs.

[0045] A single battery cell is the smallest unit that makes up a battery, and it can independently perform the functions of charging and discharging. When there are multiple battery cells, they are connected in series, parallel, or mixed connections through a busbar.

[0046] In some embodiments, the battery device may be a battery module; when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0047] In some embodiments, the battery device may be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0048] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0049] In some embodiments, the battery device may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0050] The technical solutions described in the embodiments of this application are applicable to battery devices and electrical devices that use battery devices.

[0051] Battery devices can be used as the power source for electrical devices or as energy storage units for electrical devices. Electrical devices can be, but are not limited to, mobile devices (such as mobile phones, tablets, laptops, etc.), vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0052] Electrical devices can choose the type of battery device according to their usage needs, such as individual battery cells, battery modules, or battery packs.

[0053] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0054] Figure 1 The diagram shows the structural features of a vehicle provided in some embodiments of this application.

[0055] like Figure 1 As shown, a battery device 2 is installed inside the vehicle 1. The battery device 2 can be located at the bottom, front, or rear of the vehicle 1. The battery device 2 can be used to power the vehicle 1; for example, the battery device 2 can serve as the operating power source for the vehicle 1.

[0056] The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0057] In some embodiments, the battery device 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0058] Figure 2 This is a schematic diagram of a battery explosion provided for some embodiments of this application. For example... Figure 2 As shown, the battery device 2 includes a housing 5 and battery cells (not shown), with the battery cells housed within the housing 5.

[0059] The housing 5 is used to house individual battery cells, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the individual battery cells. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as cylinders, cuboids, etc.

[0060] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0061] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0062] In battery device 2, there can be one or more battery cells. If there are multiple battery cells, they can be connected in series, in parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells are connected in both series and parallel configurations. Multiple battery cells can be directly connected in series, in parallel, or in a mixed configuration, and then the whole assembly of multiple battery cells is housed in housing 5. Alternatively, multiple battery cells can first be connected in series, in parallel, or in a mixed configuration to form battery module 6, and then multiple battery modules 6 can be connected in series, in parallel, or in a mixed configuration to form a whole assembly, which is then housed in housing 5.

[0063] Figure 3 for Figure 2 The diagram shows an exploded view of the battery module.

[0064] like Figure 3 As shown, in some embodiments, there are multiple battery cells 7, which are first connected in series, parallel, or mixed to form a battery module 6. The multiple battery modules 6 are then connected in series, parallel, or mixed to form a whole and housed in a casing.

[0065] Multiple battery cells 7 in battery module 6 can be electrically connected through a busbar component to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6.

[0066] The battery cells mentioned in the embodiments of this application may include lithium-ion battery cells or sodium-ion battery cells.

[0067] The battery cell includes an electrode assembly. The electrode assembly can be a wound structure or a stacked structure, and the embodiments of this application are not limited to this.

[0068] Electrode assemblies generally include electrode plates and separators. Electrode plates include positive electrode plates and negative electrode plates.

[0069] The electrode sheet includes a current collector, which includes a composite base film and a conductive layer located on at least one side of the composite base film. The tensile strength of the composite base film is 320MPa-450MPa, and the sum of the relative mass contents of N, P, S and O elements on the surface of the composite base film is less than or equal to 1%.

[0070] The demand for high-energy-density battery cells is increasing. Methods to improve the energy density of battery cells include increasing the specific capacity of active materials. High-specific-capacity active materials, especially negative electrode materials, are usually accompanied by significant expansion. This expansion subjects the current collector to considerable tensile force, which can lead to current collector breakage and affect the cycle performance of the battery cell. Currently used high-strength metal current collectors (such as Cu) have high densities, which is not conducive to current collector weight reduction. While lightweight polymer current collectors improve strength, they introduce some active groups. These active groups can undergo side reactions with the active materials in the battery cell, easily leading to a decrease in electrode strength during long-term charge-discharge cycles.

[0071] In this embodiment, a composite base film design for the current collector is provided to address the requirements of weight reduction and high strength. Limiting the tensile strength of the composite base film to the aforementioned range helps the current collector possess high mechanical strength, reducing the risk of deformation or even breakage caused by the expansion of the active material layer. Furthermore, since the active groups in the polymer current collector mainly include active elements such as N, O, P, and S, by keeping the mass content of active elements N, O, P, and S on the surface of the composite base film within a low range, the content of active groups on the surface of the composite base film can be reduced. This reduces the reaction consumption of active groups on the active materials in the battery cell, thereby reducing the penetration and corrosion of the first base film by the active materials and electrolyte, allowing the current collector to maintain high strength during the charge-discharge cycle of the battery cell.

[0072] In this application, the sum of the relative mass contents of N, O, P, and S elements on the surface of the composite base film can be determined using methods and instruments known in the art. For example, scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) can be used to sample and analyze the elements on the surface of the composite base film, thereby determining the chemical composition of the surface. Sampling can be performed at different locations on the surface of the composite base film, and the final result is the average value. In this application, the surface of the composite base film refers to the outermost layer. During actual sampling and testing, the EDS detection extends to a certain depth into the interior of the composite base film; this extension depth does not affect the detection results.

[0073] In this application, the method for obtaining the surface of the composite base film in the current collector can employ methods known in the art. As an example, a strong adhesive tape (such as ethylene-propylene copolymer tape) can be adhered to the surface of the current collector, and a 10cm × 10cm sample can be cut. The adhesive tape is then torn off, and the metal layer on the surface of the current collector is removed. The cross-section of the sample to be tested is then obtained using liquid nitrogen cryogenic fracture. Finally, the mass percentages of N, O, P, and S elements are measured at a depth of approximately 0.1 μm from the surface using the SEM-EDX testing method.

[0074] In this embodiment, the tensile strength of the composite base film can be 320MPa-450MPa, for example, 320MPa, 330MPa, 340MPa, 350MPa, 360MPa, 370MPa, 380MPa, 390MPa, 400MPa, 410MPa, 420MPa, 430MPa, 440MPa, 450MPa, or any range of the above values, and can be selected as 350MPa-430MPa.

[0075] In some embodiments, the composite base film includes a first base film and a second base film located on both sides of the first base film. The second base film is located between the first base film and the conductive layer. The tensile strength of the first base film is 350MPa-600MPa, for example, it can be 350MPa, 380MPa, 400MPa, 420MPa, 450MPa, 480MPa, 500MPa, 520MPa, 550MPa, 580MPa, 600MPa, or any range of the above values, and can be selected as 380MPa-580MPa. The sum of the relative mass contents of N, O, P and S elements on the surface of the second base film away from the first base film is less than or equal to 1%.

[0076] According to the embodiments of this application, the composite base film in the embodiments of this application adopts a high-strength first base film and second base film composite structure design. The high strength of the first base film can make the composite base film as a whole have high mechanical strength. By controlling the content of surface active elements in the second base film, the composite base film can have high chemical stability and reduce the reaction between the composite base film and active materials and electrolyte.

[0077] According to embodiments of this application, the composite base film formed by combining a high-strength first base film and a high-stability second base film can balance high mechanical strength and high stability. It can be applied to high-energy-density battery cells to address the high expansion problem caused by high-specific-capacity active materials and improve the cycle performance of the battery cells. Furthermore, the composite current collector is lighter than a metal current collector, and weight reduction through the current collector can further increase the energy density of the battery cell.

[0078] In some embodiments, the material of the first base film may be one or more of polyimide (PI), polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polystyrene (PS), and polycarbonate (PC).

[0079] According to the embodiments of this application, the first base film made of the above-mentioned material has high strength while also having low density, which is beneficial for reducing the weight of the current collector and further improving the energy density of the battery cell.

[0080] In some embodiments, the tensile strength of the second base film can be 100MPa-300MPa, for example, 100MPa, 120MPa, 150MPa, 160MPa, 180MPa, 200MPa, 220MPa, 250MPa, 280MPa, 300MPa, or any range of the above values, and can be selected as 140MPa-280MPa.

[0081] According to the embodiments of this application, the tensile strength of the second base film within the above-mentioned range is beneficial to further improve the strength of the current collector, reduce the risk of deformation or even breakage of the current collector caused by the expansion of the electrode sheet, and improve the cycle performance of the battery cell.

[0082] In this application, the tensile strength of the composite base film, the first base film, and the second base film are all known in the art and can be measured using methods and instruments known in the art. For example, the tensile strength can be tested at room temperature of 25°C with reference to GB / T 228.1-2010.

[0083] In some embodiments, the melting point of the second base film can be 150℃-200℃, for example, it can be 150℃, 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 200℃, or any range of the above values, and can be selected as 165℃-180℃.

[0084] According to the embodiments of this application, by controlling the tensile strength and melting point of the second base film within the above-mentioned range, it is beneficial to increase the welding strength by generating greater frictional force during the welding of the current collector and the adapter piece, thereby improving the structural stability of the battery cell.

[0085] In this application, the melting point of the second base film has a meaning known in the art and can be determined using methods and instruments known in the art.

[0086] In some embodiments, the material of the second base film may include one or more of polypropylene (PP), polyethylene (PE), and polystyrene (PS).

[0087] According to the embodiments of this application, the above-mentioned material contains only carbon and hydrogen elements. The second base film prepared from it has an extremely low content of active elements, which can further improve the stability of the current collector, reduce the side reactions between the current collector and the electrolyte and active materials, and improve the cycle performance of the battery cell.

[0088] In some embodiments, based on the total thickness of the composite base film, the thickness ratio of the first base film can be 50%-80%, for example, it can be 50%, 55%, 60%, 65%, 70%, 75%, 80%, or any range of the above values, and can be selected as 55%-70%.

[0089] According to the embodiments of this application, by controlling the thickness ratio of the first base film in the composite base film within the above-mentioned range, the current collector can have higher mechanical strength.

[0090] In some embodiments, the thickness of the first base film can be 2μm-6μm, for example, 2μm, 3μm, 4μm, 5μm, 6μm, or any range of the above values.

[0091] In some embodiments, the thickness of the second base film can be 0.5μm-3μm, for example, it can be 0.5μm, 1.0μm, 1.5μm, 2.0μm, 2.5μm, 3.0μm, or any range of the above values.

[0092] According to the embodiments of this application, by controlling the thickness of the second base film within the above-mentioned range, the current collector can have both high mechanical strength and high stability. When the second base film is too thin, its coverage effect on the first base film is poor, and it is prone to cracking, which increases the side reactions caused by the contact between the surface of the first base film and the active material or electrolyte. When the second base film is too thick, the overall strength of the current collector will decrease, affecting the structural stability of the current collector.

[0093] In some embodiments, the conductive layer may include one or more of Cu, Ag, Au, Ni, Al, and their respective alloys.

[0094] According to the embodiments of this application, the electronic conductivity of the current collector can be improved by setting a conductive layer, thus giving the current collector better electrical conductivity.

[0095] In some embodiments, the thickness of the conductive layer is 0.5μm-1.5μm, for example, it can be 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1.0μm, 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm, or any range of the above values.

[0096] According to the embodiments of this application, controlling the thickness of the conductive layer within the above-mentioned range is beneficial for the current collector to maintain both high conductivity and mechanical strength. When the conductive layer is thin, the electronic conductivity is low, resulting in poor conductivity of the current collector; when the conductive layer is thick, the overall thickness of the current collector increases, affecting the energy density of the battery cell.

[0097] In some embodiments, the current collector may further include a functional layer located between the composite base film and the conductive layer, the functional layer comprising metal particles or a binder.

[0098] According to embodiments of this application, a functional layer formed by metal particles or a binder can enhance the bonding strength of the conductive layer on the surface of the composite base film, reduce the risk of metal detachment from the conductive layer, and improve the cycle performance of the battery cell.

[0099] In some embodiments, the metal particles may include one or more of Ni, Fe, Cr, Co, and alloys of the aforementioned elements.

[0100] According to embodiments of this application, the aforementioned metal particles exhibit high bonding strength on the surface of the composite base film, which can effectively improve the adhesion stability of the conductive layer. The metal particles can be deposited on the surface of the composite base film using methods known in the art, such as spraying.

[0101] In some embodiments, the adhesive may include one or more of polyacrylates and their modified polymers.

[0102] According to the embodiments of this application, polyacrylate and its modified polymers have good bonding strength with the composite base film and the conductive layer metal, which can effectively improve the adhesion stability of the conductive layer on the composite base film.

[0103] In some embodiments, the thickness of the functional layer can be 50nm-500nm, for example, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, or any combination of the above values, and can be selected as 100nm-450nm.

[0104] In some embodiments, the sheet resistance of the current collector can be 10Ω / sq-35mΩ / s, for example, it can be 10Ω / sq, 12Ω / sq, 15Ω / sq, 18Ω / sq, 20Ω / sq, 22Ω / sq, 25Ω / sq, 28Ω / sq, 30Ω / sq, 32Ω / sq, 35Ω / sq, or any range of the above values.

[0105] According to the embodiments of this application, the sheet resistance of the current collector is within the above-mentioned range, and it has high electronic conductivity, thus the current collector has good electrical conductivity.

[0106] In this application, the sheet resistance of the current collector is a term known in the art and can be measured using methods and instruments known in the art, such as the four-probe method.

[0107] In this application, the thickness of each layer in the current collector can be measured and analyzed using SEM (scanning electron microscope) of the electrode sheet cross-section, or by using a laser thickness gauge. This application allows for microscopic morphology observation of the electrode sheet cross-section, enabling the observation of the interface between the current collector and the active material layer, thereby determining the thickness of each layer. In this application, the electrode sheet cross-section refers to a cross-section formed by slicing along the electrode sheet thickness direction. Microscopic morphology observation of the electrode sheet cross-section, combined with compositional analysis such as EDS and X-ray diffraction (XRD) analysis, can determine the elemental composition of each layer of the positive electrode sheet. Furthermore, instruments such as focused electron beam (FIB) microscopes (e.g., FEI Scios 2HiVa equipment) and ion section polishers (e.g., JEOL's IB-09010CP argon ion section polisher) can be used to polish the cross-section to obtain a clear cross-section.

[0108] In some embodiments, the electrode sheet provided in this application can be a positive electrode sheet.

[0109] [Positive electrode plate]

[0110] In some embodiments, the positive electrode includes a current collector and a positive electrode film layer located on at least one side of the current collector, the positive electrode film layer including a positive electrode active material.

[0111] As an example, the current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the current collector.

[0112] In some embodiments, the positive electrode active material may include one or more of lithium phosphate, layered lithium transition metal oxide, Prussian blue compounds, polyanionic compounds, and sodium transition metal oxide.

[0113] If the positive electrode active material is one or more of lithium phosphate and layered lithium transition metal oxide, then the positive electrode active material can be used in lithium-ion battery cells; if the positive electrode active material is one or more of Prussian blue compounds, polyanionic compounds, and sodium transition metal oxide, then the positive electrode material can be used in sodium-ion battery cells.

[0114] Lithium-containing phosphates may include one or more of lithium iron phosphate, lithium manganese phosphate, lithium manganese iron phosphate, and their respective modified compounds.

[0115] Examples of layered lithium-containing transition metal oxides may include one or more of lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their respective modified compounds.

[0116] In some embodiments, the layered lithium-containing transition metal oxide may include Ni. The molar amount of Ni may account for more than 70% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide; optionally, the molar amount of Ni may account for more than 80% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide; more preferably, the molar amount of Ni may account for more than 90% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide.

[0117] The higher the Ni content in layered lithium-containing transition metal oxides, the higher the energy density of the battery cell.

[0118] In some embodiments, layered lithium-containing transition metal oxides may include Li a Ni b Co c M d O e A fWherein, 0 < a ≤ 1.2; 0.8 ≤ b < 1; 0 < c < 1; 0 < d < 1; b + c + d = 1; 1 ≤ e ≤ 2; 0 ≤ f ≤ 1; M includes, but is not limited to, one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, and B; A includes, but is not limited to, one or more of N, F, S, and Cl. This can further improve the energy density of individual battery cells.

[0119] In some embodiments, as an example, layered lithium-containing transition metal oxides may include, but are not limited to, LiNi. 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.8 Co 0.15 Al 0.05 O2, LiNi 0.9 Co 0.06 Mn 0.04 O2, LiNi 0.92 Co 0.06 Mn 0.02 O2, LiNi 0.96 Co 0.02 Mn 0.02 O2, LiNi 0.96 Co 0.02 Mn 0.02 O2N 0.02 One or more of them.

[0120] During the charging and discharging process of a battery cell, Li undergoes insertion / extraction and consumption, resulting in varying molar Li content at different discharge states. In the examples of positive electrode active materials in this application, the molar Li content refers to the initial state of the material, i.e., the state before feeding. After charge-discharge cycles, the molar Li content may change when the positive electrode active material is applied to the battery cell.

[0121] In some embodiments, as an example, sodium transition metal oxides may include, but are not limited to:

[0122] Na 1-x Cu h Fe k Mn l M 1 m O 2-y M 1 It is one or more of Li, Be, B, Mg, Al, K, Ca, Ti, Co, Ni, Zn, Ga, Sr, Y, Nb, Mo, In, Sn, and Ba, 0 <x≤0.33,0<h≤0.24,0≤k≤0.32,0<l≤0.68,0≤m<0.1,h+k+l+m=1,0≤y<0.2;

[0123] Na 0.67 Mn 0.7 Ni z M 2 0.3-z O2, where M 2 It is one or more of Li, Mg, Al, Ca, Ti, Fe, Cu, Zn and Ba, 0 <z≤0.1;

[0124] Na a Li b Ni c Mn d Fe e O2, of which 0.67 <a≤1,0<b<0.2,0<c<0.3,

[0125] 0.67 <d+e<0.8,b+c+d+e=1。

[0126] In some embodiments, as an example, the polyanionic compound may include, but is not limited to:

[0127] A 1 f M 3 g (PO4) i O j X 1 3-j Where A is one or more of H, Li, Na, K, and NH4, and M 3 It is one or more of Ti, Cr, Mn, Fe, Co, Ni, V, Cu and Zn, X 1 It is one or more of F, Cl and Br, 0 <f≤4,0<g≤2,1≤i≤3,0≤j≤2;

[0128] Na n M 4 PO4X 2 M 4 It is one or more of Mn, Fe, Co, Ni, Cu and Zn, X 2 It is one or more of F, Cl and Br, 0 <n≤2;

[0129] Na p M 5 q (SO4)3, where M 5 It is one or more of Mn, Fe, Co, Ni, Cu and Zn, 0 <p≤2,0<q≤2;

[0130] Na s Mn t Fe3-t (PO4)2(P2O7), where 0 < s ≤ 4, 0 ≤ t ≤ 3, for example, t is 0, 1, 1.5, 2 or 3.

[0131] In some embodiments, by way of example, the Prussian blue compounds may include, but are not limited to: ...

[0132] A u M 6 v [M 7 (CN)6] w ·xH₂O, where A is H + , NH₄ + , an alkali metal cation, an alkaline earth metal cation, or one or more of them, M 6 and M 7 are each independently one or more of transition metal cations, 0 < u ≤ 2, 0 < v ≤ 1, 0 < w ≤ 1, 0 < x < 6. For example, A is H + , Li + , Na + , K + , NH₄ + , Rb + , Cs + , Fr<00​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

[0135] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins.

[0136] In some implementations, the weight percentage of the binder in the positive electrode film layer is greater than or equal to 0.5%, which is beneficial for obtaining good adhesion performance.

[0137] In some embodiments, the positive electrode film layer further includes a conductive agent. As an example, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0138] In some embodiments, the current collector serving as the positive electrode may also be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector can be made by forming a metal material, such as aluminum, aluminum alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, on the polymer material substrate. The polymer material substrate may include polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), and other substrates.

[0139] In some embodiments, the thickness of the positive current collector is from 4 μm to 20 μm. It is optionally from 6 μm to 18 μm, and more preferably from 8 μm to 16 μm.

[0140] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto a current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0141] In some embodiments, the electrode sheet provided in this application can be a negative electrode sheet.

[0142] [Negative electrode plate]

[0143] In some embodiments, the negative electrode includes a current collector and a negative electrode film layer located on at least one side of the current collector, and the negative electrode film layer may include a negative electrode active material.

[0144] As an example, the current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the current collector.

[0145] As an example, the negative electrode active material may include one or more of the following: artificial graphite, natural graphite, mesophase micro carbon spheres, hard carbon, soft carbon, silicon, and silicon-carbon composites.

[0146] Silicon-based composite materials can be prepared by methods known in the art. For example, they can be prepared by vapor deposition using graphite and silicon materials as raw materials.

[0147] In some embodiments, the negative electrode active material may further include one or more of Li, Sn, Zn and their alloys.

[0148] In some embodiments, the negative electrode film layer may further include a negative electrode conductive agent. As an example, the negative electrode conductive agent may include, but is not limited to, one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0149] In some embodiments, the negative electrode film layer may also include other additives. As an example, other additives may include thickeners, such as sodium carboxymethyl cellulose (CMC-Na), PTC thermistor materials, etc.

[0150] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. Examples of metal foils include copper foil, copper alloy foil, aluminum foil, and aluminum alloy foil. The composite current collector may include a polymeric material substrate and a metal material layer formed on at least one side of the polymeric material substrate. Examples of metal materials include, but are not limited to, one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Examples of polymeric material substrates include, but are not limited to, one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0151] The negative electrode sheet does not exclude other additional functional layers besides the negative electrode film layer. For example, in some embodiments, the negative electrode sheet may also include a conductive undercoat layer sandwiched between the negative electrode current collector and the negative electrode film layer and located on the surface of the negative electrode current collector, which may be composed of a conductive agent and a binder; in some embodiments, the negative electrode sheet may also include a protective layer covering the surface of the negative electrode film layer.

[0152] [Electrolytes]

[0153] A single battery cell includes an electrolyte.

[0154] In some embodiments, the electrolyte is an electrolyte solution, which includes an electrolyte salt and an organic solvent.

[0155] In some embodiments, the electrolyte includes anion, which may include bis(fluorosulfonyl)imide anion (FSI). - ), bis(trifluoromethanesulfonyl)imide anion (TFSI) - ), dioxaborate anion (BOB) - ), difluorooxalate borate anion (DFOB) - ), difluorodioxanol phosphate anion (DFOP) - ), tetrafluorooxalate phosphate anion (TFOP) - ), difluorophosphate anion (PO2F2) - ), hexafluorophosphate anion (PF6) - ), tetrafluoroborate anion (BF4) - ), hexafluoroarsenate anion (AsF6) - ), trifluoromethanesulfonate anion (CF3SO3) - One or more of the following.

[0156] In some embodiments, the electrolyte includes cations, which may include one or more of lithium ions and sodium ions.

[0157] In some embodiments, the concentration of the electrolyte salt may be 0.3 mol / L or higher, optionally 0.7 mol / L or higher, and further optionally 4 mol / L or lower, optionally 2.5 mol / L or lower, or 1.7 mol / L or lower. When the concentration of the electrolyte salt is within the above range, the electrolyte can have a suitable ionic conductivity.

[0158] Organic solvents may include, but are not limited to, one or more of esters, ethers, sulfones, and nitriles. Esters may include, but are not limited to, one or more of carbonates, phosphate esters, carboxylic esters, sulfate esters, and sulfonates. Carbonates may include cyclic carbonates and / or chain carbonates; optionally, carbonates may include both cyclic and chain carbonates. Chain carbonates may include low-viscosity polar chain carbonates, aliphatic branched carbonates, etc.

[0159] As an example, organic solvents may include, but are not limited to, ethylene carbonate (EC), propylene carbonate (PC), butene carbonate, ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), diethyl sulfone (ESE), dimethyl ether tetraethylene glycol (TEGDME), ethylene glycol dimethyl ether (DME), 1,3-dioxolane (DOL), trimethyl phosphate, 3-methoxypropionitrile, H(CF2)2OCH3, C4F9O CH3, H(CF2)2OCH2CH3, H(CF2)2OCH2CF3, H(CF2)2CH2O(CF2)2H, CF3CHFCF2OCH3, CF3CHFCF2OCH2CH3, 2-trifluoromethylhexafluoropropyl methyl ether, 2-trifluoromethylhexafluoropropyl ethyl ether, 2-trifluoromethylhexafluoropropyl propyl ether, 3-trifluoromethyloctafluorobutyl methyl ether, 3-trifluoromethyloctafluorobutyl ethyl ether, 3-trifluoromethyloctafluorobutyl propyl ether, 4-trifluoromethyl One or more of the following: decafluoropentyl methyl ether, 4-trifluoromethyl decafluoropentyl ethyl ether, 4-trifluoromethyl decafluoropentyl propyl ether, 5-trifluoromethyl dodecylfluorohexyl methyl ether, 5-trifluoromethyl dodecylfluorohexyl ethyl ether, 5-trifluoromethyl dodecylfluorohexyl propyl ether, 6-trifluoromethyl tetradecafluoroheptyl methyl ether, 6-trifluoromethyl tetradecafluoroheptyl ethyl ether, 6-trifluoromethyl tetradecafluoroheptyl propyl ether, 7-trifluoromethyl hexadecylfluorooctyl methyl ether, 7-trifluoromethyl hexadecylfluorooctyl ethyl ether, and 7-trifluoromethyl hexadecylfluorooctyl propyl ether.

[0160] In some embodiments, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature performance, additives that improve battery low-temperature power performance, etc.

[0161] [Isolation Component]

[0162] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0163] In some embodiments, the isolation chamber includes an isolation membrane. This application does not impose any particular limitation on the type of isolation membrane; any known porous membrane with good chemical and mechanical stability can be selected.

[0164] In some embodiments, the material of the separator may include at least one selected from glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation. The separator may be a single component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating may also be applied to the surface of the separator.

[0165] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0166] Example

[0167] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0168] Example 1

[0169] Positive electrode sheet

[0170] LiNi, the positive electrode active material 0.8 Co 0.1 Mn 0.1 O2, conductive carbon black, and polyvinylidene fluoride (PVDF) binder are mixed in a mass ratio of 95:3:2 and then added to the solvent N-methylpyrrolidone (NMP) to uniformly disperse and obtain a positive electrode slurry. The positive electrode slurry is coated onto the surface of the positive electrode current collector aluminum foil, and then dried, cold-pressed, and slit to obtain the positive electrode sheet.

[0171] Negative electrode sheet

[0172] A negative electrode slurry is prepared by uniformly mixing silicon-carbon anode active material, thickener sodium carboxymethyl cellulose (CMC-Na), conductive agent super P, and binder styrene-butadiene rubber (SBR) in deionized water at a mass ratio of 92:2:1:5. The negative electrode slurry is then uniformly coated onto the negative electrode current collector Ti foil, and after cold pressing and slitting, the negative electrode sheet is obtained.

[0173] The negative electrode current collector includes a composite base film, a Ni metal functional layer (150 nm thick) on both sides of the composite base film, and a Cu conductive layer (1 μm thick) on the side of the functional layer away from the composite base film. The composite base film includes a first base film PI and a second base film PP on both sides of the first base film. The composite base film is prepared by melt co-extrusion.

[0174] Separating membrane

[0175] A polyethylene (PE) film with a thickness of 12μm was selected.

[0176] electrolyte

[0177] The electrolyte solvent is a mixture of ethylene carbonate, diethyl carbonate, and dimethyl carbonate in a volume ratio of 1:1:1. The electrolyte salt is LiPF6, and the concentration of the electrolyte salt is 1 mol / L.

[0178] battery cell

[0179] The positive electrode, negative electrode, and separator are stacked in sequence and then injected with electrolyte to obtain a single battery cell.

[0180] Examples 2-9

[0181] The preparation method of the battery cell is similar to that in Example 1, except that the parameters of the negative electrode current collector are different. For details of the parameter adjustments, please refer to Table 1.

[0182] Table 1

[0183]

[0184]

[0185] Example 10

[0186] The preparation method of the battery cell is similar to that of Example 1, except that the functional layer of the current collector is removed, while the rest is the same as that of Example 1.

[0187] Example 11

[0188] The preparation method of the battery cell is similar to that of Example 1, except that the negative current collector in Example 1 is replaced with the aluminum foil of the positive current collector, while the rest is the same as that of Example 1.

[0189] Test section

[0190] 1. Thermal shrinkage rate of the current collector

[0191] The battery cell is disassembled to obtain the negative electrode sheet. The negative electrode active material layer on the surface of the negative electrode sheet is peeled off to obtain the negative electrode current collector. The width of the negative electrode current collector is measured at room temperature as D0. The negative electrode current collector is placed at 130℃ for 1 min and the width of the negative electrode current collector is measured as D1. The heat shrinkage rate (%) = (D1-D0) / D0×100%.

[0192] 2. Full charge elongation of the negative electrode sheet

[0193] Before preparing the wound battery cell, two points are marked on the negative electrode sheet, with a distance of 10cm between the two marks. Then, the battery cell is assembled and charged to 4.2V at a constant current of 0.33C. The battery cell is then disassembled to obtain the negative electrode sheet. The distance L (cm) between the two marks is measured again. The full charge elongation (%) is calculated as (L-10) / 10×100%.

[0194] 3. Welding strength of negative electrode sheet

[0195] Disassemble the battery cell to obtain the negative electrode sheet. The tab part of the negative electrode sheet is welded with an adapter piece. Use a tensile testing machine, with one end of the clamp holding the adapter piece and the other end holding the end of the electrode sheet away from the adapter piece, and stretch it at a speed of 50 mm / min. Record the tensile force when the weld on the adapter piece is completely pulled apart.

[0196] 4. Energy density of individual battery cells

[0197] Weigh the battery cell and record its mass m (kg); charge the battery cell at 0.33C constant current to 4.2V at 25℃, let it stand for 5 minutes, and then discharge it at 0.33C constant current to 2.5V. Repeat the above charge and discharge cycle 3 times and record the discharge energy W (Wh) of the third cycle. The ratio of discharge energy to the mass of the battery cell is recorded as the energy density (Wh / kg).

[0198] 5. Cycle performance of individual battery cells

[0199] At 60℃, charge the battery cell to 4.25V at a constant current of 0.33C, let it stand for 5 minutes, and then discharge it to 2.8V at a constant current of 0.33C. Record the discharge capacity C0. Repeat the above charge and discharge cycle for 300 cycles and record the discharge capacity C1 on the 300th cycle. Cycle capacity retention rate (%) = C1 / C0 × 100%.

[0200] The test results are detailed in Table 2.

[0201] Table 2

[0202]

[0203]

[0204] Combining the data from Example 1, Comparative Example 1, and Comparative Example 2, it can be seen that the composite base film obtained by combining a high-strength first base film and a high-stability second base film can enable the battery cell to have a higher cycle capacity retention rate, and the elongation of the negative electrode sheet of the battery cell is lower under full charge, indicating that the composite base film has better structural stability. Although Comparative Example 3 also uses a composite base film structure, the second base film is made of PET material, which contains more active elements on its surface, resulting in more side reactions with the electrolyte and active materials, leading to a deterioration in the cycle performance of the battery cell.

[0205] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A battery cell, characterized in that, The device includes an electrode sheet, the electrode sheet including a current collector, the current collector including a composite base film and a conductive layer located on at least one side of the composite base film; The tensile strength of the composite base film is 320MPa-450MPa; The sum of the relative mass contents of N, O, P and S elements on the surface of the composite base film is less than or equal to 1%.

2. The battery cell according to claim 1, characterized in that, The composite base film includes a first base film and a second base film located on both sides of the first base film. The second base film is located between the first base film and the conductive layer. The tensile strength of the first base film is 350MPa-600MPa. The sum of the relative mass contents of N, O, P and S elements on the surface of the second base film away from the first base film is less than or equal to 1%.

3. The battery cell according to claim 2, characterized in that, The first base film material includes one or more of polyimide, polyethylene terephthalate, polyethylene, polypropylene, polystyrene, and polycarbonate.

4. The battery cell according to claim 2 or 3, characterized in that, The second base film satisfies at least one of the following conditions (1) and (2): (1) The tensile strength of the second base film is 100MPa-300MPa; (2) The melting point of the second base film is 150℃-200℃.

5. The battery cell according to any one of claims 2-4, characterized in that, The material of the second base film includes one or more of polypropylene, polyethylene, and polystyrene, and the material of the second base film is different from that of the first base film.

6. The battery cell according to any one of claims 2-5, characterized in that, Based on the total thickness of the composite base film, the thickness of the first base film accounts for 50%-80%.

7. The battery cell according to claim 6, characterized in that, The thickness of the first base film is 2μm-6μm; and / or The thickness of the second base film is 0.5μm-3μm.

8. The battery cell according to any one of claims 1-7, characterized in that, The conductive layer includes one or more of Cu, Ag, Au, Ni, Al, and their respective alloys.

9. The battery cell according to any one of claims 1-8, characterized in that, The thickness of the conductive layer is 0.5μm-1.5μm.

10. The battery cell according to any one of claims 1-9, characterized in that, The current collector further includes a functional layer located between the composite base film and the conductive layer, and the functional layer includes metal particles or a binder.

11. The battery cell according to claim 10, characterized in that, The metal particles include one or more of Ni, Fe, Cr, Co, and alloys of the aforementioned metal elements.

12. The battery cell according to claim 10 or 11, characterized in that, The adhesive includes one or more of polyacrylates and their modified polymers.

13. The battery cell according to any one of claims 10-12, characterized in that, The thickness of the functional layer is 50nm-500nm.

14. The battery cell according to any one of claims 1-13, characterized in that, The sheet resistance of the current collector is 10Ω / sq-35mΩ / sq.

15. The battery cell according to any one of claims 1-14, characterized in that, The electrode plates include one or both of positive and negative electrode plates.

16. The battery cell according to claim 15, characterized in that, The electrode sheet is a negative electrode sheet, and the negative electrode sheet includes a negative electrode film layer located on at least one side surface of the current collector, and the negative electrode film layer includes a negative electrode active material.

17. The battery cell according to claim 16, characterized in that, The negative electrode active material includes one or more of Li, Sn, Zn, carbon-based materials, and silicon-based materials.

18. The battery cell according to claim 17, characterized in that, The silicon-based material includes silicon-carbon composite materials.

19. A battery device, characterized in that, Includes the battery cell according to any one of claims 1-18.

20. An electrical device, characterized in that, Includes the battery cell according to any one of claims 1-18 or the battery device according to claim 19.

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