Battery cell, battery device and electric device

Abstract

The utility model relates to the technical field of batteries, in particular to a battery monomer, a battery device and a power utilization device, and the battery monomer comprises a positive pole piece and a negative pole piece; the positive pole piece comprises a positive composite current collector; the negative pole piece comprises a negative composite current collector; each of the positive electrode composite current collector and the negative electrode composite current collector independently comprises a polymer layer and a metal layer arranged on at least one outer surface of the polymer layer; the polymer layer and the metal layer are provided with holes; the porosity of the positive electrode composite current collector and the porosity of the negative electrode composite current collector are independently smaller than or equal to 30%. The battery monomer disclosed by the utility model has relatively good quick charging performance.

Description

Technical Field

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

[0002] Battery cells are widely used in various fields due to their excellent performance. However, in current products, the electrolyte diffusion distance is relatively long during the charging and discharging process, which affects the fast charging performance of the battery cells.

[0003] Therefore, it is crucial to develop a battery cell that can overcome the above-mentioned defects. Utility Model Content

[0004] In view of the above problems, this application provides a battery cell, a battery device, and an electrical device, wherein the battery cell has good fast charging performance.

[0005] In a first aspect, this application provides a battery cell, the battery cell comprising a positive electrode and a negative electrode;

[0006] The positive electrode plate includes a positive composite current collector; the negative electrode plate includes a negative composite current collector;

[0007] The positive electrode composite current collector and the negative electrode composite current collector each independently include a polymer layer and a metal layer disposed on at least one outer surface of the polymer layer;

[0008] The polymer layer and the metal layer are provided with pores;

[0009] The porosity of the positive electrode composite current collector and the negative electrode composite current collector are each independently less than or equal to 30%.

[0010] In the technical solution of this application, the positive or negative electrode sheet has pores in the polymer layer and the metal layer. A certain amount of electrolyte can be retained in the polymer layer or the metal layer. During the charging and discharging process of the battery cell, the electrolyte can diffuse from the polymer layer to the metal layer with a short diffusion distance, which improves the fast charging performance of the battery cell. In addition, by adjusting the porosity of the positive electrode composite current collector and the negative electrode composite current collector to the specified range, the pores in the polymer layer or the metal layer not only act as channels, but also retain a certain amount of electrolyte, which is beneficial to improving the fast charging performance of the battery cell.

[0011] In some embodiments, the porosity of the polymer layer is 5%-30%.

[0012] In the technical solution of this application, adjusting the porosity of the polymer layer within the specified range is beneficial to improving the fast charging performance of the battery cell. On the other hand, it can achieve a certain structural stability without significantly increasing the thickness of the polymer layer, resulting in less space encroachment on the active material in the battery cell and minimal loss of the battery cell's energy density.

[0013] In some embodiments, the thickness of the polymer layer is 1-8 μm.

[0014] In the technical solution of this application embodiment, adjusting the thickness of the polymer layer within the specified range allows the formed positive electrode composite current collector or negative electrode composite current collector to retain electrolyte and improve the fast charging performance of the battery cell. In addition, with the thickness within the specified range, the polymer layer provides basic support and minimizes the space occupation of the active material in the battery cell, thus not significantly reducing the energy density of the battery cell.

[0015] In some embodiments, the number of metal layers on one outer surface of the polymer layer is 1-5; and / or;

[0016] The total thickness of the metal layer on one outer surface of the polymer layer is less than or equal to 3 μm; and / or;

[0017] The metal layer is more than one layer, and the thickness of the metal layer closest to the polymer layer is less than or equal to 100 nm.

[0018] In the technical solution of this application, the thickness of the metal layer is within the above-mentioned range, and the thickness of the positive electrode composite current collector or negative electrode current collector is relatively thin, and the electrolyte diffusion channel is relatively short, which further improves the fast charging performance of the battery cell. In addition, the thin metal layer occupies less space for the active material in the battery cell and has less impact on the energy density of the battery cell. Adjusting the number of metal layers and the thickness of the metal layer closest to the polymer layer in the multi-layer metal layer makes it easier to adjust the size and distribution of the pores as needed, forming a battery cell with excellent fast charging performance.

[0019] In some embodiments, the porosity of the metal layer is 10%-30%.

[0020] In the technical solution of this application, the porosity of the metal layer is within the above-mentioned range, and the thickness of the metal layer can be adjusted to be relatively thin, which has little impact on the conductivity of the positive electrode composite current collector or the negative electrode composite current collector. At the same time, it also facilitates the diffusion of electrolyte through the metal layer during the charging and discharging process of the battery cell, thereby improving the fast charging performance of the battery cell.

[0021] In some embodiments, the equivalent diameter of a single hole cross-section in the metal layer is 10-1000 nm; and / or;

[0022] In the metal layer, the distance between two adjacent holes is 10-1000 nm.

[0023] In the technical solution of this application, the diameter of a single hole in the metal layer and the distance between adjacent holes are adjusted so that the holes in the metal layer are evenly distributed and of moderate size. The holes can not only serve as diffusion channels for electrolytes, but also retain a certain amount of electrolytes, which is beneficial to improving the fast charging performance of the battery cells.

[0024] In some embodiments, the positive electrode composite current collector and the negative electrode composite current collector are each independently provided with a packing region, and the packing region is provided with packing.

[0025] In the technical solution of this application, setting a filler area can further improve the fast charging performance of the battery cell, and filler can also be set as needed to realize the multi-functional design of positive electrode composite current collector and negative electrode composite current collector.

[0026] In some embodiments, the filling zone includes at least two independently distributed regions; and / or;

[0027] The distance between two adjacent regions is less than or equal to 1 μm.

[0028] In the technical solution of this application, the filler is designed with distinct regions and the distance between two adjacent regions is adjusted so that the filler regions are distributed as evenly as possible in the positive electrode composite current collector or the negative electrode composite current collector. On the one hand, this satisfies the contribution of the filler regions to the fast charging capability, and on the other hand, it reduces the adverse effects of the excessive concentration of the filler regions on the safety or other electrical performance of the positive electrode or the negative electrode sheet.

[0029] In some embodiments, the filler region is at least partially disposed within the polymer layer and / or the metal layer.

[0030] In the technical solution of this application, the distribution of the packing region can be adaptively adjusted by adjusting the positional relationship between the packing region and the polymer layer or metal layer, thereby realizing the diversified design of positive electrode composite current collector or negative electrode composite current collector.

[0031] In some embodiments, the average particle size of the filler in the filler region is 10-5000 nm.

[0032] In the technical solution of this application, the average particle size of the filler in the filler region is within the above-mentioned range. It can be evenly distributed in the filler region, and can also effectively adsorb and retain electrolyte. It can effectively realize its basic function according to the function of the filler, and can also improve the fast charging performance of the battery cell.

[0033] In a second aspect, this application provides a battery device comprising a plurality of battery cells according to the first aspect.

[0034] Thirdly, this application provides an electrical device, which includes the battery cell described in the first aspect, or the battery device described in the second aspect.

[0035] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0036] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0037] Figure 1 This is a schematic diagram of the negative electrode composite current collector in some embodiments of this application;

[0038] Figure 2 This is a schematic diagram of the negative electrode composite current collector in some embodiments of this application;

[0039] Figure 3 This is a schematic diagram of the negative electrode composite current collector in some embodiments of this application;

[0040] The reference numerals in the detailed embodiments are as follows:

[0041] 1-Polymer layer; 2-Metal layer; 21-First metal layer; 22-Second metal layer; 3-Filling region. Detailed Implementation

[0042] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0044] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0045] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0046] 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 also 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 "2-10" indicates that all real numbers between "2-10" have been listed in this article; "2-10" 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.

[0047] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0048] Currently, the poor fast-charging performance of individual battery cells limits their application.

[0049] This application improves the fast-charging performance of a single battery cell by creating pores in the metal and polymer layers of the positive and negative composite current collectors and adjusting their porosity. This application also provides a single battery cell, a battery device, and an electrical device.

[0050] [Battery cell]

[0051] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0052] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0053] This application provides a battery cell, which includes a positive electrode and a negative electrode.

[0054] The positive electrode plate includes a positive composite current collector; the negative electrode plate includes a negative composite current collector;

[0055] The positive electrode composite current collector and the negative electrode composite current collector each independently include a polymer layer and a metal layer disposed on at least one outer surface of the polymer layer;

[0056] The polymer layer and the metal layer are provided with pores;

[0057] The porosity of the positive electrode composite current collector and the negative electrode composite current collector are each independently less than or equal to 30%, for example, 5%, 10%, 15%, 20%, 25%, 30%, etc.

[0058] In this application, porosity refers to the parameter that represents the ratio of the volume of pores inside the material to the total volume of the material, expressed in percentage (%).

[0059] In this application, the porosity testing process is as follows:

[0060] (1) Sample preparation: Prepare samples by cutting the positive electrode composite current collector or the negative electrode composite current collector into slices;

[0061] (2) Test the apparent volume of the sample: Use a universal ruler to test the length, width and thickness of the sample, calculate the apparent volume of the sample, and record it as V1;

[0062] (3) Test the true volume of the sample: The gas displacement method is used for testing. The sample is placed in a true density tester, and helium is introduced into the closed test system according to the procedure. The pressure of the gas in the sample chamber and the expansion chamber is detected, and the true volume of the sample is calculated according to Bohr's law (PV=nRT), which is denoted as V2.

[0063] (4) Porosity calculation: It is calculated based on the percentage of the pore volume inside the sample to the total volume of the sample. The calculation formula is as follows:

[0064] Porosity = (V1-V2) / V1×100%, where V1 is the apparent volume of the sample and V2 is the actual volume of the sample.

[0065] In the technical solution of this application, the positive or negative electrode sheet has pores in the polymer layer and metal layer. A certain amount of electrolyte can be retained in the polymer layer or metal layer. During the charging and discharging process of the battery cell, the electrolyte can diffuse from the polymer layer through the metal layer and diffuse from the composite current collector to the electrode material layer in the film layer containing active material, such as from the positive composite current collector to the positive film layer and from the negative composite current collector to the negative film layer. The diffusion distance is short, which improves the fast charging performance of the battery cell. In addition, by adjusting the porosity of the positive and negative composite current collectors to the specified range, the pores in the polymer layer or metal layer not only act as channels but also retain a certain amount of electrolyte, which is beneficial to improving the fast charging performance of the battery cell.

[0066] In some embodiments, the porosity of the polymer layer is 5%-30%, such as 10%, 15%, 20%, 25%, 30%, etc.

[0067] In order to achieve high energy density and low cost, battery cells generally need to increase the thickness of the positive or negative electrode plates, which makes the electrolyte diffusion distance longer during the charging and discharging process, affecting the fast charging performance of the battery cell.

[0068] In the technical solution of this application, adjusting the porosity of the polymer layer within the specified range is beneficial to improving the fast charging performance of the battery cell. On the other hand, it can achieve a certain structural stability without significantly increasing the thickness of the polymer layer, resulting in less space encroachment on the active material in the battery cell and minimal loss of the battery cell's energy density.

[0069] In some embodiments, the thickness of the polymer layer is 1-8 μm, such as 2 μm, 4 μm, 6 μm, etc.

[0070] In the technical solution of this application embodiment, adjusting the thickness of the polymer layer within the specified range allows the formed positive electrode composite current collector or negative electrode composite current collector to retain electrolyte and improve the fast charging performance of the battery cell. In addition, with the thickness within the specified range, the polymer layer provides basic support and minimizes the space occupation of the active material in the battery cell, thus not significantly reducing the energy density of the battery cell.

[0071] In some embodiments, the number of metal layers on one outer surface of the polymer layer is 1-5 layers (e.g., 2 layers, 3 layers, 4 layers, etc.); and / or;

[0072] The total thickness of the metal layer on one outer surface of the polymer layer is less than or equal to 3 μm (e.g., 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, etc.); and / or;

[0073] The metal layer is more than one layer, and the thickness of the metal layer closest to the polymer layer is less than or equal to 100nm, such as 10nm, 20nm, 40nm, 60nm, 80nm, etc.

[0074] In the technical solution of this application, the thickness of the metal layer is within the above-mentioned range, and the thickness of the positive electrode composite current collector or negative electrode current collector is relatively thin, and the electrolyte diffusion channel is relatively short, which further improves the fast charging performance of the battery cell. In addition, the thin metal layer occupies less space for the active material in the battery cell and has less impact on the energy density of the battery cell. Adjusting the number of metal layers and the thickness of the metal layer closest to the polymer layer in the multi-layer metal layer makes it easier to adjust the size and distribution of the pores as needed, forming a battery cell with excellent fast charging performance.

[0075] In some embodiments, the porosity of the metal layer is 10%-30%, such as 15%, 20%, 25%, 30%, etc.

[0076] In the technical solution of this application, the porosity of the metal layer is within the above-mentioned range, and the thickness of the metal layer can be adjusted to be relatively thin, which has little impact on the conductivity of the positive electrode composite current collector or the negative electrode composite current collector. At the same time, it also facilitates the diffusion of electrolyte through the metal layer during the charging and discharging process of the battery cell, thereby improving the fast charging performance of the battery cell.

[0077] In some embodiments, the equivalent diameter of a single hole cross-section in the metal layer is 10-1000 nm, such as 50 nm, 100 nm, 200 nm, 400 nm, 600 nm, 800 nm, etc.; and / or;

[0078] In the metal layer, the distance between two adjacent holes is 10-1000nm, such as 50nm, 100nm, 200nm, 400nm, 600nm, 800nm, etc.

[0079] In this application, the equivalent diameter refers to the diameter of the smallest circumcircle of the hole's cross-section; the distance between two adjacent holes refers to the distance between the centers of the smallest circumcircles of two adjacent holes.

[0080] In the technical solution of this application, the diameter of a single hole in the metal layer and the distance between adjacent holes are adjusted so that the holes in the metal layer are evenly distributed and of moderate size. The holes can not only serve as diffusion channels for electrolytes, but also retain a certain amount of electrolytes, which is beneficial to improving the fast charging performance of the battery cells.

[0081] In some embodiments, the positive electrode composite current collector and the negative electrode composite current collector are each independently provided with a packing region, and the packing region is provided with packing.

[0082] In the technical solution of this application embodiment, setting a filler area can further improve the fast charging performance of the battery cell, and filler can also be set as needed to realize the multi-functional design of positive electrode composite current collector and negative electrode composite current collector.

[0083] In some embodiments, the filling region includes at least two independently distributed regions; and / or;

[0084] The distance between two adjacent regions is less than or equal to 1 μm, such as 50 nm, 100 nm, 200 nm, 400 nm, 600 nm, 800 nm, etc.

[0085] In the technical solution of this application, the filler is designed with distinct regions and the distance between two adjacent regions is adjusted so that the filler regions are distributed as evenly as possible in the positive electrode composite current collector or the negative electrode composite current collector. On the one hand, this satisfies the contribution of the filler regions to the fast charging capability, and on the other hand, it reduces the adverse effects of the excessive concentration of the filler regions on the safety or other electrical performance of the positive electrode or the negative electrode sheet.

[0086] In some embodiments, the filler region is at least partially disposed in the polymer layer and / or the metal layer.

[0087] In the technical solutions of this application embodiment, the distribution of the filler region can be adaptively adjusted by adjusting the positional relationship between the filler region and the polymer layer or metal layer, thereby realizing the diversified design of positive electrode composite current collector or negative electrode composite current collector.

[0088] In some embodiments, the average particle size of the filler in the filler region is 10-5000 nm, such as 50 nm, 100 nm, 200 nm, 400 nm, 600 nm, 800 nm, 1000 nm, 1500 nm, 2000 nm, 2500 nm, 3000 nm, 3500 nm, etc.

[0089] In this application, the average particle size refers to the statistical average value of the particle size of the particle group, specifically the volume average particle size; the average particle size is tested by laser method or scanning electron microscopy observation method.

[0090] In the technical solution of this application embodiment, the average particle size of the filler in the filler region is within the above-mentioned range. It can be evenly distributed in the filler region, and can also effectively adsorb and retain electrolyte. It can effectively realize its basic function according to the function of the filler, and can also improve the fast charging performance of the battery cell.

[0091] In this application, the metal layer can be made of any known material. For example, the metal layer may be made of stainless steel, copper, copper alloys, aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, or silver alloys. For instance, aluminum may be used for the metal layer in the positive electrode composite current collector, and copper may be used for the metal layer in the negative electrode composite current collector.

[0092] In this application, the polymer layer can be made of any known material. For example, the polymer layer may be made of, but is not limited to, polyethylene, polypropylene, polyvinylidene fluoride, polyethylene terephthalate, or polyimide; the polymer layer may also be made of known absorbent materials.

[0093] In this application, the filler in the filler region can be selected as needed, including but not limited to any one or a combination of at least two of alumina (Al2O3), silicon dioxide (SiO2), titanium dioxide (TiO2), magnesium oxide (MgO) or zinc oxide (ZnO).

[0094] In this application, the preparation method of the positive electrode or the negative electrode can adopt the known operation and is not specifically limited. As an example, the preparation methods of the positive electrode and the negative electrode are provided below.

[0095] Preparation method of positive electrode sheet

[0096] In some embodiments, the positive electrode sheet can be obtained by the following preparation method:

[0097] (1) At least one metal layer is disposed on the surface of the polymer layer (e.g., by magnetron sputtering), and a metal layer (e.g., Ga) is disposed on the surface of the polymer layer. + (Ion beam or plasma treatment) of the pores to obtain a positive electrode composite current collector;

[0098] (2) Dissolve the positive electrode material, such as positive electrode active material, conductive agent (e.g., carbon nanotubes), binder (e.g., polyvinylidene fluoride), and other arbitrary components (e.g., dispersant) in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coat the positive electrode slurry onto the surface of the positive electrode composite current collector to form a positive electrode film layer, and then dry, cold press, and slit to obtain a positive electrode sheet.

[0099] In some embodiments, the positive electrode composite current collector is further provided with a packing region, and the method for providing the packing region includes, but is not limited to, the following operations:

[0100] 1) Provide filler regions (e.g., fillers) into the polymer layer;

[0101] 2) After setting a filler area on the polymer surface (e.g., by magnetron sputtering or spraying), a metal layer is then applied;

[0102] 3) Set up filler zones between metal layers (e.g., through magnetron sputtering or spraying);

[0103] 4) A filler region is provided (e.g., by magnetron sputtering) at least partially penetrating the polymer layer and the metal layer.

[0104] In some embodiments, during the cold pressing process, some of the filler in the filler region may penetrate the metal layer and enter the polymer layer. Alternatively, filler regions may be provided in both the polymer layer and the metal layer.

[0105] In this application, the porosity of the metal layer is controlled during the process of setting the pores. The polymer layer can be a commercially available product that meets the porosity requirements of this application, or the polymer surface can be modified during the preparation of the polymer layer to adjust the porosity.

[0106] Preparation method of negative electrode sheet

[0107] (1) At least one metal layer is disposed on the surface of the polymer layer (e.g., by magnetron sputtering), and a metal layer (e.g., Ga) is disposed on the surface of the polymer layer. + (Ion beam or plasma treatment) of the pores to obtain a negative electrode composite current collector;

[0108] (2) Dissolve the negative electrode material, such as negative electrode active material (e.g., graphite), conductive agent (e.g., carbon black), binder (e.g., styrene-butadiene rubber), and other arbitrary components (e.g., dispersant) in a solvent (e.g., water) to form a negative electrode slurry; coat the negative electrode slurry onto the surface of the negative electrode composite current collector to form a negative electrode film layer, and then dry, cold press, and slit to obtain a negative electrode sheet.

[0109] In some embodiments, the negative electrode composite current collector is further provided with a packing region, and the method for providing the packing region includes, but is not limited to, the following operations:

[0110] 1) Provide filler regions (e.g., fillers) into the polymer layer;

[0111] 2) After setting a filler area on the polymer surface (e.g., by magnetron sputtering or spraying), a metal layer is then applied;

[0112] 3) Set up filler zones between metal layers (e.g., through magnetron sputtering or spraying);

[0113] 4) A filler region is provided (e.g., by magnetron sputtering) at least partially penetrating the polymer layer and the metal layer.

[0114] In some embodiments, during the cold pressing process, some of the filler in the filler region may penetrate the metal layer and embed itself into the polymer layer. Alternatively, filler regions may be provided simultaneously in both the polymer layer and the metal layer.

[0115] [Isolation Component]

[0116] In some embodiments, the battery cell further includes a separator disposed between the positive electrode and the negative electrode.

[0117] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0118] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can 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 can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or it can 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 can also be applied to the surface of the separator.

[0119] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrode plates, serving both to transport ions and to isolate the positive and negative electrode plates.

[0120] [Electrolytes]

[0121] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel-like, or solid.

[0122] Liquid electrolytes include electrolyte salts and solvents.

[0123] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0124] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents 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, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0125] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0126] The gel electrolyte includes a polymer as a backbone network and can be used in conjunction with an ionic liquid—lithium salt.

[0127] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0128] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0129] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0130] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0131] [shell]

[0132] In some embodiments, the battery cell may include a casing. The casing may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc. In some embodiments, the casing may be a sealed structure or a non-sealed structure. As an example, when the casing is a non-sealed structure, the casing serves to protect the electrode assembly (including a positive electrode, a negative electrode, and a separator, with the separator disposed between the positive and negative electrode). A sealing bag is also included between the casing and the electrode assembly, and the sealing bag is used to encapsulate the electrode assembly and the electrolyte. Specifically, the sealing bag may be a bag-shaped insulating component or an aluminum-plastic film. When the casing is a sealed structure, it is used to encapsulate components such as the electrode assembly and the electrolyte.

[0133] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0134] In some embodiments, the housing includes an end cap and a housing, the housing having an opening, and the end cap covering the opening. The housing may have one or more openings. The end cap may also be provided one or more.

[0135] [Electrode terminals]

[0136] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab. The electrode terminal can be directly connected to the tab, or it can be indirectly connected to the tab through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0137] [Pressure relief mechanism]

[0138] In some embodiments, a pressure relief mechanism is provided on the casing. The pressure relief mechanism is used to release the internal gas of the battery cell.

[0139] As an example, the internal pressure or temperature of a battery cell is actuated to release the internal pressure or temperature when it reaches a predetermined threshold. When the internal pressure or temperature of the battery cell reaches the predetermined threshold, the pressure relief mechanism is activated or a weak structure in the pressure relief mechanism is broken, thereby creating an opening or channel for the internal pressure or temperature to be released. The threshold design varies depending on the design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell.

[0140] As an example, the pressure relief mechanism can be integrally molded with the housing.

[0141] As an example, the pressure relief mechanism can also be separately installed and connected to the housing.

[0142] The term "actuation" as used in this application refers to the activation or actuation of the pressure relief mechanism to a certain state, thereby releasing the internal pressure and temperature of the battery cell. The actions of the pressure relief mechanism may include, but are not limited to: movement of components within the mechanism to form an exhaust channel, rupture, breakage, tearing, or opening of at least a portion of the mechanism, etc. When the pressure relief mechanism is activated, the high-temperature, high-pressure substances inside the battery cell are discharged as waste from the activated portion. This method allows for pressure and temperature relief of the battery cell under controllable pressure or temperature, thereby preventing potentially more serious accidents.

[0143] In some embodiments, when the housing is a non-sealed structure, the pressure relief mechanism can be configured as a through hole for venting gas inside the battery cell.

[0144] The emissions from battery cells mentioned in this application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0145] [Battery Device]

[0146] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0147] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0148] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0149] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0150] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be housed in the housing by fixing the battery module in the housing.

[0151] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0152] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0153] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0154] 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.

[0155] [ Electrical appliances ]

[0156] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use individual battery cells, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0157] [Example]

[0158] Example 1

[0159] Negative electrode composite current collector: Its structural schematic diagram is as follows Figure 1 As shown, a metal layer (copper, 2 μm) was magnetron sputtered onto each of the two surfaces of polymer layer 1 (polypropylene film, 5 μm, porosity 10%), and then subjected to Ga... + Ion beam etching is used to create pores with equivalent diameters ranging from 10 to 1000 nm. The distance between two adjacent pores is controlled between 10 and 1000 nm to form a metal layer 2 with a porosity of 5%, resulting in a negative electrode composite current collector with a porosity of 8%.

[0160] Negative electrode sheet: Negative electrode active material (graphite), conductive agent (Super P) and binder (carboxymethyl cellulose) are dissolved in solvent (water) at a mass ratio of 95:2:3 to form a negative electrode slurry; the negative electrode slurry is coated on the surface of the negative electrode composite current collector to form a negative electrode film layer, and then dried, cold pressed and slit to obtain the negative electrode sheet.

[0161] Positive electrode composite current collector: The difference between it and negative electrode composite current collector is that the metal material is aluminum.

[0162] Positive electrode sheet: The positive active material (LFP), conductive agent (Super P) and binder (PVDF) are dissolved in a solvent (N-methylpyrrolidone) at a mass ratio of 95:3:2 to form a negative electrode slurry; the negative electrode slurry is coated on the surface of the positive electrode composite current collector to form a positive electrode film layer, and then dried, cold-pressed and slit to obtain the negative electrode sheet.

[0163] Separator: A polyethylene film with an Al2O3 coating of 7μm is used as the separator.

[0164] Electrolyte: The electrolyte salt (LiPF6) is dissolved in a solvent (EC:DMC:PC = 1:1:1) to form an electrolyte, wherein the concentration of the electrolyte salt is 1 mol / L.

[0165] Battery cell: The positive electrode, separator, and negative electrode are stacked and wound in sequence to obtain the cell; the cell is placed in the outer packaging, electrolyte is added, and after vacuum sealing, standing, formation, shaping, capacity measurement and other processes, the battery cell is obtained.

[0166] Example 2

[0167] The difference between this embodiment and Embodiment 1 lies in the different negative electrode composite current collector, as shown in the schematic diagram below. Figure 2 As shown, a metal layer (copper, 50 nm) is magnetron sputtered on each of the two surfaces of polymer layer 1 (polypropylene film, 5 μm, porosity 15%), and then isolated alumina particles are sputtered. The average particle size of the alumina particles is distributed between 10-1000 nm, and the distance between two adjacent alumina particles is controlled between 10-1000 nm. Then, a metal layer (copper, 2 μm) is electroplated using a water electroplating process, with at least some alumina particles not plated with copper, forming a second metal layer 22. During the cold pressing process of the negative electrode sheet, the alumina particles penetrate the thinner metal to form a first metal layer 21 and a filler region 3, resulting in a negative electrode composite current collector with a porosity of 12%.

[0168] Example 3

[0169] The difference between this embodiment and Embodiment 1 lies in the different negative electrode composite current collector, as shown in the schematic diagram below. Figure 3 As shown, a layer of alumina particles was sprayed onto both surfaces of polymer layer 1 (polypropylene film, 5 μm, porosity 20%). The average particle size of the alumina particles was distributed between 50-5000 nm, and the distance between two adjacent alumina particles was controlled to be less than 1 μm, forming filler region 3. Then, a layer of metal (copper, 2 μm) was magnetron sputtered onto the two surfaces of the polymer layer, and then subjected to Ga... +Ion beam etching is used to create pores with equivalent diameters ranging from 10 to 1000 nm. The distance between two adjacent pores is controlled between 10 and 1000 nm to form a metal layer 2 with a porosity of 10%, resulting in a negative electrode composite current collector with a porosity of 16%.

[0170] Example 4

[0171] The difference between this embodiment and Embodiment 1 is that the porosity of the polymer layer is 3%, while the rest are the same as in Embodiment 1.

[0172] Example 5

[0173] The difference between this embodiment and Embodiment 1 is that the porosity of the metal layer is 35%, while the rest are the same as in Embodiment 1.

[0174] Example 6

[0175] The difference between this embodiment and Embodiment 1 is that the thickness of the metal layer is 4 μm, while the rest is the same as in Embodiment 1.

[0176] Example 7

[0177] The difference between this embodiment and Embodiment 1 lies in the negative electrode composite current collector. Specifically, a metal layer (copper, 2μm) is magnetron sputtered onto each of the two surfaces of the polymer layer (polypropylene film, 8μm, porosity 5%), and then subjected to Ga... + Ion beam etching creates pores with equivalent diameters ranging from 10 to 1000 nm, and the distance between two adjacent pores is controlled between 10 and 1000 nm, forming a metal layer with a porosity of 10%, resulting in a negative electrode composite current collector with a porosity of 7%.

[0178] Example 8

[0179] The difference between this embodiment and Embodiment 1 lies in the negative electrode composite current collector. Specifically, a layer of metal (copper, 3μm) is magnetron sputtered onto each of the two surfaces of the polymer layer (polypropylene film, 5μm, porosity 30%), and then subjected to Ga... + Ion beam etching was used to etch pores with equivalent diameters ranging from 10 to 1000 nm, and the distance between adjacent pores was controlled within the range of 10 to 1000 nm, forming a metal layer with a porosity of 30%, resulting in a negative electrode composite current collector with a porosity of 30%. (Comparative Example 1)

[0180] The difference between this comparative example and Example 1 is that the negative electrode composite current collector is different. Specifically, the metal layer does not include holes, but everything else is the same as in Example 1.

[0181] Comparative Example 2

[0182] The difference between this comparative example and Example 1 is that the negative electrode composite current collector is different. The porosity of both the polymer layer and the metal layer is 35%, and the porosity of the negative electrode composite current collector is 35%. All other aspects are the same as in Example 1.

[0183] Performance testing

[0184] (1) Fast charging performance: Each battery was charged at a rate of 0.33C to a voltage of 3.8V at room temperature, and then discharged at a rate of 0.33C to a voltage of 2.0V. The discharge capacity C0 was measured. Then, the battery was charged to 80% SOC using a multi-step constant current charging method or a constant power charging method, and the charging time t was recorded.

[0185] (2) Energy density: The weight M of all active materials loaded per unit area on the positive electrode sheet of the secondary batteries in the above embodiments and comparative examples was measured respectively. The discharge energy S0 was measured after each battery was charged at room temperature at a rate of 0.33C to a voltage of 3.8V, and then discharged at a rate of 0.33C to a voltage of 2.0V. The formula for calculating the battery mass energy density is as follows:

[0186] Battery mass energy density = S0 / M.

[0187] The test results are summarized in Table 1.

[0188] Table 1

[0189] Charging time / min Energy density / Wh / kg Example 1 15.0 283 Example 2 12.2 280 Example 3 10.0 282 Example 4 18.3 279 Example 5 16.6 284 Example 6 14.0 265 Example 7 13.2 276 Example 8 13.5 279 Comparative Example 1 25.0 281 Comparative Example 2 23.1 282

[0190] Analysis of the data in Table 1 shows that the energy density of the battery cell described in this application is between 265-284Wh / kg, and the charging time is within 18.3 minutes. The battery cell described in this application has excellent fast charging performance without losing energy density.

[0191] Analysis of Comparative Examples 1-2 and Example 1 shows that the performance of Comparative Examples 1-2 is not as good as that of Example 1, proving that the battery cell described in this application has better performance.

[0192] Analysis of Examples 4-6 and Example 1 shows that the performance of Examples 4-6 is not as good as that of Example 1, proving that adjusting the metal layer or polymer layer of the positive electrode composite current collector or negative electrode composite current collector within the specified range results in a better performance of the formed battery cell.

[0193] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, The battery cell includes a positive electrode and a negative electrode; The positive electrode plate includes a positive composite current collector; the negative electrode plate includes a negative composite current collector; The positive electrode composite current collector and the negative electrode composite current collector each independently include a polymer layer and a metal layer disposed on at least one outer surface of the polymer layer; The polymer layer and the metal layer are provided with pores; The porosity of the positive electrode composite current collector and the negative electrode composite current collector are each independently less than or equal to 30%.

2. The battery cell according to claim 1, characterized in that, The porosity of the polymer layer is 5%-30%.

3. The battery cell according to claim 1 or 2, characterized in that, The thickness of the polymer layer is 1-8 μm.

4. The battery cell according to claim 1, characterized in that, The number of metal layers on one outer surface of the polymer layer is 1-5; and / or; The total thickness of the metal layer on one outer surface of the polymer layer is less than or equal to 3 μm; and / or; The metal layer is more than one layer, and the thickness of the metal layer closest to the polymer layer is less than or equal to 100 nm.

5. The battery cell according to claim 1, characterized in that, The porosity of the metal layer is 10%-30%.

6. The battery cell according to claim 1, characterized in that, In the metal layer, the equivalent diameter of the cross-section of a single hole is 10-1000 nm; and / or; In the metal layer, the distance between two adjacent holes is 10-1000 nm.

7. The battery cell according to claim 1, characterized in that, The positive electrode composite current collector and the negative electrode composite current collector are each independently provided with a packing zone, and the packing zone is provided with packing.

8. The battery cell according to claim 7, characterized in that, The filling zone includes at least two independently distributed regions; and / or; The distance between two adjacent regions is less than or equal to 1 μm.

9. The battery cell according to claim 7 or 8, characterized in that, The filler region is at least partially disposed in the polymer layer and / or the metal layer.

10. The battery cell according to claim 7, characterized in that, The average particle size of the filler in the filler zone is 10-5000 nm.

11. A battery device, characterized in that, The battery device comprises a plurality of battery cells according to any one of claims 1-10.

12. An electrical appliance, characterized in that, The electrical device includes a single battery cell as described in any one of claims 1-10, or a battery device as described in claim 11.

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