Battery monomer and preparation method thereof, battery device and power utilization device

Abstract

The invention relates to a battery monomer and a preparation method thereof, a battery device and a power utilization device. The battery monomer comprises a positive pole piece, an isolating membrane and a negative pole piece, at least one surface of the isolating membrane is provided with binder particles; the binder microparticles include a fibrous material and a polymeric binder latex. The isolating membrane has good ion transmission capability, and is beneficial to reducing the direct-current internal resistance of the battery and improving the comprehensive performance.

Description

Technical Field

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

[0002] Rechargeable batteries are widely used in various consumer electronics products, electric vehicles, and energy storage devices. With industry development, higher performance requirements are being placed on rechargeable batteries.

[0003] In secondary batteries, the separator primarily functions to isolate the positive and negative electrodes while allowing ion transport. The performance of the separator directly affects the battery's interface structure and internal resistance; therefore, a high-performance separator plays a crucial role in improving battery performance. Summary of the Invention

[0004] The purpose of this application is to provide a battery cell and its preparation method, a battery device and an electrical device, wherein the battery cell adopts an improved separator membrane with good ion transport capability, thereby helping to reduce the DC internal resistance of the battery.

[0005] Therefore, the first aspect of this application provides a battery cell, which includes a positive electrode, a separator, and a negative electrode;

[0006] At least one surface of the isolation membrane has adhesive particles; the adhesive particles include fibrous materials and polymer adhesive latex.

[0007] A separator containing binder microparticles can achieve interfacial adhesion with the electrode sheets, thereby helping to suppress cell deformation caused by electrode expansion and contraction during battery cycling. Furthermore, these binder microparticles include both polymer binder latex (typically granular) and fibrous materials. The accumulation of these two different shapes creates numerous pores, providing abundant lithium-ion transport channels. This, in turn, helps reduce the battery's DC internal resistance (DCR).

[0008] In some embodiments, the adhesive particles are distributed discontinuously on the surface of the release membrane.

[0009] Compared to a continuous distribution (e.g., forming a continuous adhesive layer), the adhesive particles can still provide some adhesion when they are discontinuously distributed. Furthermore, the adhesive particles only cover part of the surface of the separator, and the surface not covered by the adhesive particles is more conducive to ion transport, thereby further reducing DCR.

[0010] In some embodiments, for the surface of the release membrane having the adhesive particles, the projected area of ​​the adhesive particles on the release membrane surface accounts for 5% to 50% of the surface area of ​​the release membrane; the direction of the projection is perpendicular to the surface of the release membrane.

[0011] When the area of ​​the binder particles covering the surface of the separator reaches the above-mentioned range, the bonding effect and the overall ion conduction performance of the separator can be better balanced, which is conducive to comprehensively improving the cycle performance and capacity retention of the battery.

[0012] In some embodiments, the mass ratio of the fibrous material to the polymer adhesive latex in the adhesive particles is (20-100):100.

[0013] When the mass ratio of fibrous material to polymer binder latex is within the above range, the binder particles can provide a sufficient pore structure while having good adhesion, which is beneficial for ion transport.

[0014] In some embodiments, the morphology of the fibrous material includes at least one selected from the group consisting of rod-shaped, tubular, rod-shaped, and fibrous.

[0015] The fibrous materials described above can all be used in conjunction with polymer binder latex to create a porous structure when forming microparticles, facilitating ion transport.

[0016] In some embodiments, the diameter of the fibrous material is 1–100 nm; and / or,

[0017] The length of the fibrous material is 0.1–10 μm.

[0018] When the fibrous material has the aforementioned diameter and / or length, the battery exhibits a superior DCR value. This may be because the fibrous material is more likely to generate abundant channels suitable for ion transport when it forms microparticles with a solid granular polymer binder.

[0019] In some embodiments, the fibrous material includes at least one of the following: cellulose, lignin, carbon fiber, polyester fiber, polyamide fiber (e.g., aromatic polyamide fiber), and polyacrylonitrile fiber.

[0020] The aforementioned fibrous materials exhibit good electrochemical stability and are stable to electrolytes, making them suitable for use in battery systems. These materials include natural materials (such as cellulose and lignin) as well as synthetic materials. When natural materials are used, their inherent nanopores and porous structures provide additional ion channels, further enhancing ion transport capabilities.

[0021] In some embodiments, the polymer binder latex includes polyacrylate latex.

[0022] Polyacrylate latexes hardly swell in electrolyte solvents and are very stable during charge and discharge, making them particularly suitable for use on separator surfaces. They also possess strong adhesive properties, and even when adhesive particles are distributed discontinuously across a portion of the separator surface, they can effectively bond adjacent electrode plates.

[0023] In some embodiments, the polyacrylate latex is a copolymer formed from at least one monomer selected from the group consisting of: methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, butyl acrylate, butyl methacrylate, isooctyl acrylate, isooctyl methacrylate, acrylic acid, methacrylic acid, acrylamide, and styrene.

[0024] The above lists several monomers that can be used to form polyacrylate latexes. These monomers have main chain and side chain structures of suitable length, resulting in polyacrylate latexes with stable structure and excellent adhesion, making them more suitable for battery systems.

[0025] In some embodiments, the adhesive particles further contain a dispersant; the mass ratio of the fibrous material, the polymer adhesive latex, and the dispersant in the adhesive particles is (20-100):100:(2-15).

[0026] When granulating fibrous materials and polymer binder latex into microparticles (e.g., using spray drying), the addition of dispersants helps improve the granulation yield and has almost no negative impact on battery performance.

[0027] In some embodiments, the binder particles have a unit area weight of 0.5–2.6 g / m² on the release membrane. 2 .

[0028] When the binder particles have the aforementioned weight per unit area, it is beneficial to better balance the adhesion between the separator and adjacent electrode plates, as well as the ion transport capacity of the separator. Furthermore, the aforementioned dosage is also an easy and economical choice for preparation.

[0029] In some embodiments, the separator includes a base film, a functional coating disposed on at least one surface of the base film, and adhesive microparticles disposed on the surface of the functional coating; the functional coating contains inorganic particles.

[0030] The binder microparticles can be directly applied to the base film, or a functional coating can be applied to the base film first, followed by the binder microparticles. When a functional coating containing inorganic particles is used, it is beneficial to improve the mechanical properties of the separator and has a certain effect on improving the heat resistance, puncture resistance, and other properties of the separator.

[0031] A second aspect of this application provides a method for preparing a single battery cell, comprising the following steps:

[0032] A release membrane is provided, at least one surface of which has adhesive particles; the adhesive particles comprise fibrous material and polymeric adhesive latex.

[0033] A battery cell is prepared by assembling the positive electrode, the negative electrode, and the separator.

[0034] The battery cell described in the first aspect of this application can be prepared by the above method. Its excellent performance is as described in the first aspect of this application, and will not be repeated here.

[0035] In some embodiments, the particle size Dv50 of the binder microparticles is 5–15 μm.

[0036] During the preparation process, binder microparticles with the above-mentioned particle size are used so that after the separator is assembled with the positive and negative electrode sheets and pressed, the binder microparticles can still retain a certain amount of internal pores that are not completely compressed. These pores are conducive to ion transport.

[0037] In some embodiments, the glass transition temperature (Tg) of the binder particles is less than 60°C.

[0038] When the glass transition temperature of the binder particles falls within the above range, it helps them maintain good flexibility and adhesive strength under the temperature conditions during battery use.

[0039] A third aspect of this application provides a battery device comprising the battery cell described in the first aspect of this application, or a battery cell prepared according to the preparation method described in the second aspect of this application.

[0040] A fourth aspect of this application provides an electrical device that includes the battery device described in the third aspect of this application.

[0041] 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, it can be implemented according to the contents of the specification. In order to make the above and other objects, features and advantages of this application more obvious and understandable, the specific implementation methods of this application are listed below. Attached Figure Description

[0042] 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. In the drawings:

[0043] Figure 1 This is a schematic diagram of a battery cell according to one embodiment of this application;

[0044] Figure 2 yes Figure 1 An exploded view of a battery cell according to an embodiment of this application is shown.

[0045] Figure 3 This is a schematic diagram of a battery module according to one embodiment of this application;

[0046] Figure 4 This is a schematic diagram of a battery pack according to one embodiment of this application;

[0047] Figure 5 yes Figure 4 An exploded view of a battery pack according to one embodiment of this application is shown;

[0048] Figure 6 This is a schematic diagram of an electrical device in which a single battery cell is used as a power source according to an embodiment of this application;

[0049] Explanation of reference numerals in the attached figures:

[0050] 1 Battery pack; 2 Upper housing; 3 Lower housing; 4 Battery module; 5 Battery cell; 51 Casing; 52 Electrode assembly; 53 End cap. Detailed Implementation

[0051] Exemplary embodiments of this disclosure will now be described in more detail. It should be understood that this disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0052] 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 the 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 ​​1 and 2 are listed, and maximum range values ​​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 "a–b" 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" and "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.

[0053] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0054] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0055] Unless otherwise specified, all steps of 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.

[0056] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0057] In secondary batteries, the separator primarily functions to isolate the positive and negative electrodes while allowing ion transport. The performance of the separator directly impacts the battery's interface structure and internal resistance; a high-performance separator plays a crucial role in improving battery performance. During charging and discharging, both the positive and negative electrode materials may expand and contract due to ion insertion / extraction, potentially leading to cell deformation. To address this, existing technologies employ separators with adhesive coatings, which can bond to the positive and negative electrode plates at the interface, thus helping to suppress cell deformation. However, the application of adhesive coatings often introduces the problem of increased battery drain-resistance ratio (DCR).

[0058] This application finds that the adhesive coating of existing separators is typically composed of polymer particles, which have poor ion transport capabilities and can negatively impact battery performance. This application primarily improves the ion transport performance of the separator by applying adhesive microparticles comprising fibrous materials and polymer binder latex, thereby reducing the battery's damping rate (DCR).

[0059] The solutions described in the embodiments of this application are applicable to battery cells, battery devices using the battery cells, and electrical devices using the battery cells or battery devices.

[0060] battery cell

[0061] 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.

[0062] The battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0063] [Electrode Assembly]

[0064] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator positioned between the positive and negative electrodes. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0065] [Isolation membrane]

[0066] In some embodiments, at least one surface of the release membrane has adhesive particles; the adhesive particles include fibrous materials and polymer adhesive latex.

[0067] The separator containing the aforementioned binder microparticles can form an interfacial bond with the electrode sheets, thereby helping to suppress cell deformation caused by electrode expansion and contraction during battery cycling. Furthermore, these binder microparticles include both polymer binder latex (typically granular) and fibrous materials. The accumulation of these two different shapes to form microparticles creates numerous pores, providing abundant lithium-ion transport channels, which helps reduce the battery's DC internal resistance (DCR).

[0068] In some embodiments, the adhesive particles are distributed discontinuously on the surface of the release membrane.

[0069] Compared to a continuous distribution (e.g., forming a continuous adhesive layer), the adhesive particles, even with a discontinuous distribution, can still provide a certain degree of adhesion. Those skilled in the art will understand that the adhesive particles provided in this embodiment have improved ion transport capabilities compared to adhesives in the prior art (e.g., particulate polymer adhesives). For the portion of the separator membrane without adhesive, ions only need to pass through the separator membrane body; therefore, it is easier for ions to pass through the area of ​​the separator membrane without adhesive. The discontinuous distribution ensures that the adhesive particles only cover a portion of the separator membrane surface, leaving surfaces uncovered by the adhesive particles, which is more conducive to ion transport, thereby further reducing DCR.

[0070] In some embodiments, for the surface of the release membrane having the adhesive particles, the projected area of ​​the adhesive particles on the release membrane surface accounts for 5% to 50% of the surface area of ​​the release membrane; the direction of the projection is perpendicular to the release membrane surface. For example, the percentage of the projected area of ​​the adhesive particles on the release membrane surface to the surface area of ​​the release membrane can be selected from about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc.

[0071] In general, the larger the surface area of ​​the separator covered by binder microparticles, the stronger the adhesion, but this also makes the separator's ion transport capacity more likely to decrease to some extent. When the surface area of ​​the separator covered by binder microparticles is within the above-mentioned range, the adhesion and the overall ion conduction performance of the separator can be better balanced, which is beneficial to comprehensively improving the battery's cycle performance and capacity retention.

[0072] In some embodiments, the mass ratio of the fibrous material to the polymer adhesive latex in the adhesive particles is (20-100):100; for example, it can be about 20:100, 25:100, 30:100, 35:100, 40:100, 45:100, 50:100, 55:100, 60:100, 65:100, 70:100, 75:100, 80:100, 85:100, 90:100, 95:100, 100:100, etc.

[0073] A higher proportion of fibrous material makes it easier for the binder particles to have abundant pores; a lower proportion of fibrous material makes it easier for the binder particles to have stronger adhesive force. When the mass ratio of fibrous material to polymer binder latex is within the above range, the binder particles can provide a sufficient pore structure while maintaining good adhesive force, which is beneficial for ion transport.

[0074] In some embodiments, the morphology of the fibrous material includes at least one selected from the group consisting of rod-shaped, tubular (e.g., hollow tubular), rod-shaped, and fibrous.

[0075] The fibrous materials described above can all be used in conjunction with polymer binder latex to create a porous structure when forming microparticles, facilitating ion transport.

[0076] In some embodiments, the diameter of the fibrous material is 1–100 nm; and / or,

[0077] The length of the fibrous material is 0.1–10 μm. For example, the diameter of the fibrous material can be approximately 1 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, etc.; the length of the fibrous material can be approximately 0.1 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, etc.

[0078] When the fibrous material has the aforementioned diameter and / or length, the battery exhibits a superior DCR value. This may be because the fibrous material is more likely to generate abundant channels suitable for ion transport when it forms microparticles with a solid granular polymer binder.

[0079] In some embodiments, the fibrous material includes at least one of the following: cellulose, lignin, carbon fiber, polyester fiber, polyamide fiber (e.g., aromatic polyamide fiber), and polyacrylonitrile fiber.

[0080] The aforementioned fibrous materials exhibit good electrochemical stability and are stable to electrolytes, making them suitable for use in battery systems. These materials include natural materials (such as cellulose and lignin) as well as synthetic materials. When natural materials are used, their inherent nanopores and porous structures provide additional ion channels, further enhancing ion transport capabilities.

[0081] In some embodiments, the polymer binder latex includes polyacrylate latex.

[0082] Polyacrylate latexes hardly swell in electrolyte solvents and are very stable during charge and discharge, making them particularly suitable for use on separator surfaces. They also possess strong adhesive properties, and even when adhesive particles are distributed discontinuously across a portion of the separator surface, they can effectively bond adjacent electrode plates.

[0083] In some embodiments, the polyacrylate latex is a copolymer formed from at least one monomer selected from the group consisting of: methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, butyl acrylate, butyl methacrylate, isooctyl acrylate, isooctyl methacrylate, acrylic acid, methacrylic acid, acrylamide, and styrene. In some embodiments, the polyacrylate latex includes styrene-acrylate copolymers, such as styrene-methyl acrylate copolymers, styrene-ethyl acrylate copolymers, etc.

[0084] The above lists several monomers that can be used to form polyacrylate latexes. These monomers have main chain and side chain structures of suitable length, resulting in polyacrylate latexes with stable structure and excellent adhesion, making them more suitable for battery systems.

[0085] In some embodiments, the adhesive particles further contain a dispersant; the mass ratio of the fibrous material, the polymer adhesive latex, and the dispersant in the adhesive particles is (20-100):100:(2-15). For example, when the weight parts of the polymer adhesive latex are 100, the weight parts of the fibrous material can be arbitrarily selected from 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, etc., and the weight parts of the dispersant can be arbitrarily selected from 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, etc. In some embodiments, the dispersant can be arbitrarily selected from the group consisting of: sodium polyacrylate, sodium polymethacrylate, polypropylene ether, polyethylene glycol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, etc.

[0086] The primary role of dispersants is to improve the yield during the formation of binder latex. When granulating fibrous materials and polymer binder latex into microparticles (e.g., using spray drying), the addition of dispersants helps to improve the granulation yield, and the dispersants themselves have almost no negative impact on battery performance.

[0087] In some embodiments, the binder particles have a unit area weight of 0.5–2.6 g / m² on the release membrane. 2 For example, it can be approximately 0.5 g / m 2 1g / m 2 1.2g / m 2 1.4g / m 2 1.6g / m 2 1.8g / m 2 2g / m 2 2.2g / m 2 2.4g / m 2 2.6g / m 2 wait.

[0088] When the binder particles have the aforementioned weight per unit area, it is beneficial to better balance the adhesion between the separator and adjacent electrode plates, as well as the ion transport capacity of the separator. Furthermore, the aforementioned dosage is also an easy and economical choice for preparation.

[0089] In some embodiments, the separator includes a base film and a functional coating disposed on at least one surface of the base film, wherein the adhesive microparticles are disposed on the surface of the functional coating; the functional coating contains inorganic particles. For example, the inorganic particles may be selected from alumina, boehmite, ceramics, etc.

[0090] The binder microparticles can be directly applied to the base film, or a functional coating can be applied to the base film first, followed by the binder microparticles. When a functional coating containing inorganic particles is used, it is beneficial to improve the mechanical properties of the separator and has a certain effect on improving the heat resistance, puncture resistance, and other properties of the separator.

[0091] In some embodiments, the base film of the separator can be made of at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The base film of the separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the base film of 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.

[0092] In some embodiments, the binder microparticles are prepared by providing a slurry comprising fibrous material and polymer binder latex, and then preparing the binder microparticles by spray drying.

[0093] In some embodiments, the particle size Dv50 of the binder microparticles is 5 to 15 μm; for example, it can be about 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, etc.

[0094] During the preparation process, binder microparticles with the aforementioned particle size are used. This ensures that after the separator is assembled with the positive and negative electrode sheets and pressed, the binder microparticles retain some internal channels that are not completely compressed. These channels facilitate ion transport. It should be noted that after being fabricated into a battery, the binder microparticles may become slightly flattened due to the pressing process and may undergo slight deformation due to swelling. Therefore, the binder microparticles obtained from disassembling the battery may not have the aforementioned particle size.

[0095] In some embodiments, the glass transition temperature (Tg) of the binder particles is less than 60°C.

[0096] When the glass transition temperature of the binder particles falls within the above range, it helps them maintain good flexibility and adhesive strength under the temperature conditions during battery use.

[0097] The glass transition temperature of a material can be determined as follows: Refer to ASTM D3418-2015. Sample preparation: Punch a thin film sample into a small disc with a diameter of 6 mm. Weigh 1-3 mg, place it in an Al crucible, flatten it, invert the crucible lid, and then close the lid. Parameter settings include: nitrogen atmosphere, purge gas 50 mL / min, protective gas 100 mL / min. Temperature rise program: ① 10℃ / min, 25℃~200℃ ② 10℃ / min, 200℃~-70℃; ③ 10℃ / min, -70℃~200℃, end.

[0098] [Positive electrode plate]

[0099] In some embodiments, the positive electrode includes a positive current collector and a positive electrode material layer disposed on at least one surface of the positive current collector; the positive electrode material layer contains a positive electrode active material.

[0100] In some embodiments, the positive current collector may be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals may be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0101] In some embodiments, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0102] In some embodiments, the positive electrode material layer may optionally include a binder. For example, the binder may include one or more combinations selected from the group consisting of: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0103] In some embodiments, the positive electrode material layer may optionally include a conductive agent. For example, the conductive agent may include one or more combinations selected from the group consisting of: Super P, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0104] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned positive electrode active material, as well as optional conductive agents, binders and any other components in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto a positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0105] [Negative electrode plate]

[0106] The negative electrode sheet includes a negative electrode active material. In some embodiments, the negative electrode sheet includes a negative electrode current collector and a negative electrode material layer disposed on at least one surface of the negative electrode current collector, the negative electrode material layer including the negative electrode active material.

[0107] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper 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 may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0108] In some embodiments, the negative electrode active material layer may employ negative electrode active materials known in the art for lithium-ion batteries. For example, the negative electrode active material includes one or more combinations selected from the group consisting of: natural graphite, artificial graphite, mesophase microcarbon spheres (MCMB), hard carbon, soft carbon, silicon, silicon-carbon composites, Li-Sn alloys, Li-Sn-O alloys, Sn, SnO, SnO2, TiO2-Li4Ti5O 12 Li-Al alloy.

[0109] In some embodiments, the negative electrode material layer may optionally include a binder. For example, the binder may include one or more combinations selected from the group consisting of: styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0110] In some embodiments, the negative electrode material layer may optionally include a conductive agent. For example, the conductive agent may include one or more combinations selected from the group consisting of: Super P, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0111] In some embodiments, the negative electrode material layer may also optionally include other additives. For example, other additives may be thickeners (such as sodium carboxymethyl cellulose (CMC-Na)).

[0112] In some embodiments, the negative electrode sheet can be prepared by dispersing the components of the above-mentioned negative electrode material layer, such as negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0113] [Electrolytes]

[0114] In some embodiments, the battery cell further includes an electrolyte; the electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte, which can be selected according to requirements. The electrolyte can be liquid, gel-like, or solid.

[0115] Liquid electrolytes include electrolyte salts and solvents.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] [Structure of the electrode assembly]

[0120] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0121] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0122] In some implementations, the electrode assembly is a stacked structure.

[0123] As an example, multiple positive and negative electrode plates can be set, and multiple positive and multiple negative electrode plates can be stacked alternately.

[0124] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0125] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0126] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0127] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0128] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0129] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0130] [shell]

[0131] 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, and a sealing bag is included between the casing and the electrode assembly to encapsulate the electrode assembly and 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 electrolyte.

[0132] 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 impose any particular limitations. For example, Figure 1 This is an example of a square-shell battery cell 5.

[0133] In some implementations, refer to Figure 2 The outer casing includes an end cap 53 and a housing 51. The housing 51 has an opening, and the end cap 53 covers the opening. The housing 51 may have one or more openings. The end cap 53 may also have one or more. The positive electrode, negative electrode, and separator may be formed into an electrode assembly 52 by a winding process or a stacking process. The electrode assembly 52 is encapsulated within a receiving cavity formed by the housing 51 and the end cap 53. The electrolyte is immersed in the electrode assembly 52.

[0134] [Electrode terminals]

[0135] 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.

[0136] [Pressure relief mechanism]

[0137] 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.

[0138] 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 forming 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.

[0139] As an example, the pressure relief mechanism can be integrally molded with the housing.

[0140] As an example, the pressure relief mechanism can also be separately installed and connected to the housing.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] Battery device

[0145] 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.

[0146] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0147] 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. Figure 3 This is battery module 4 as an example. (See reference...) Figure 3 In the battery module 4, multiple battery cells 5 can be arranged sequentially along the length of the battery module 4. Of course, they can also be arranged in any other way.

[0148] 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.

[0149] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing. Figure 4 and Figure 5 This is battery pack 1 as an example. (See reference...) Figure 4 and Figure 5 The battery pack 1 may include a housing and multiple battery modules 4 disposed within the housing. The housing includes an upper housing 2 and a lower housing 3, with the upper housing 2 covering the lower housing 3 to form a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery pack.

[0150] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0151] 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.

[0152] 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.

[0153] 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.

[0154] Electrical appliances

[0155] 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. Figure 6 This is an example of an electrical device. The electrical device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0156] Example 1

[0157] This embodiment provides a lithium-ion battery cell, the preparation method of which is as follows, and the relevant parameters and test results are shown in Table 1:

[0158] (1) Positive electrode plate

[0159] A positive electrode slurry was prepared by thoroughly mixing polyvinylidene fluoride (PVDF), lithium iron phosphate (LFP), conductive agent carbon black, and N-methylpyrrolidone (NMP) at a mass ratio of 1.2:60.38:0.42:38. The positive electrode slurry was then subjected to a process at 197 g / m³. 2 The loading is uniformly coated on the positive current collector aluminum foil, and then dried, cold-pressed and cut to obtain the positive electrode sheet.

[0160] (2) Negative electrode plate

[0161] Natural graphite, conductive agent acetylene black, binder styrene-butadiene rubber (SBR), and thickener sodium carboxymethyl cellulose (CMC-Na) were added to deionized water at a mass ratio of 95.5:1.2:1.6:1.7. The mixture was thoroughly stirred and mixed to prepare a negative electrode slurry (solid content 64%). This negative electrode slurry was then subjected to a concentration of 102 g / m³. 2 The loading amount is coated on the negative electrode current collector copper foil, and then dried, cold pressed and slit to obtain the negative electrode sheet.

[0162] (3) Separating membrane

[0163] 1. Preparation of binder microparticles

[0164] Styrene-ethyl acrylate copolymer (as polymer binder latex), cellulose (fiber length 1 μm, diameter 20 nm) (as fibrous material), and polyacrylamide (as dispersant) were weighed in a mass ratio of 100:50:10. Water and the above raw materials were mixed evenly to obtain a binder slurry (solid content 20%). After spray drying (inlet air temperature 120℃, outlet air temperature 65℃, hydraulic pressure 0.3MPa), binder microparticles with a particle size Dv50 of 7.0 μm were prepared.

[0165] 2. Preparation of the separating membrane

[0166] A commercially available PE microporous film (from Zhuogao Electronics Technology Co., Ltd.) with a thickness of 7 μm and an average pore size of 80 nm was used as the substrate. The aforementioned adhesive microparticles and polyacrylic acid glue were mixed at a mass ratio of 100:15 and stirred evenly in deionized water to obtain a release film slurry (solid content of 20%). The release film slurry was sprayed onto one surface of the substrate, dried to remove the solvent, and the release film was obtained. The coating density of the adhesive microparticles on the substrate was 1.8 g / m². 2 The projected area of ​​the adhesive particles on the separator accounts for 20% of the surface area of ​​the separator.

[0167] (4) Electrolyte

[0168] At 25°C, ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain a mixed solvent. LiPF6 is then dissolved in the above mixed solvent to obtain an electrolyte, wherein the concentration of LiPF6 is 1 mol / L.

[0169] (5) Secondary battery

[0170] The positive electrode, separator, and negative electrode are stacked, wound, and hot-pressed in sequence to obtain a battery cell. The battery cell is placed in an outer packaging, and the electrolyte prepared above is added. After processes such as encapsulation, standing, formation, and aging, a secondary battery is obtained.

[0171] Test using the following method:

[0172] I. Adhesion test:

[0173] The negative electrode sheet and the separator were overlapped and placed on a hot press. The hot press parameters were set as follows: temperature 65℃, pressure 5MPa, and time 10s. A separator / negative electrode sheet sample was obtained by applying pressure to obtain a bonded sample. The separator / negative electrode sheet sample was then cut into rectangular strips of 150×20mm. One side of each rectangular strip was attached to a steel plate using double-sided adhesive. At one end of the rectangular strip, the separator and the electrode sheet were separated by 2cm along the length direction to obtain the test sample.

[0174] Keep the steel plate horizontal and fix it with the lower clamp of the universal testing machine (Xieqiang Instrument Manufacturing (Shanghai) Co., Ltd., model CTM2100). Fix the peeled end of the separator as described above with the upper clamp of the universal testing machine and connect it to a tensile testing machine. Set the test conditions to a tensile rate of 20 mm / min and a horizontal pull of 10 cm. After the tensile force stabilizes, record the tensile force value. The adhesion force between the separator and the electrode is obtained by the ratio of the tensile force value to the sample width.

[0175] II. Ionic Conductivity Test of Separating Membrane

[0176] Based on a confined symmetric cell method, the conductivity of the separator is calculated by measuring the Rs obtained in the EIS of symmetric cells with different numbers of separator layers. The testing procedure is as follows:

[0177] (1) Preparation of the isolation membrane: Cut the isolation membrane to be tested into samples of the same size (45.3mm*33.7mm), and bake the samples at 60℃ for at least 4 hours, and then quickly transfer them into a 25℃ Class 100 clean glove box for later use.

[0178] (2) Preparation of Symmetrical Battery Confinement Pocket Bag (Symmetrical Battery Confinement Aluminum-Plastic Bag (Aluminum-Plastic Bag is a common commercial product of polypropylene and aluminum foil composite for soft-pack batteries)): Blank symmetric batteries are assembled using Cu Foil to Cu Foil (copper foil to copper foil) as current collectors. The confinement of this Pocket Bag is achieved by punching a hole in the center of the green adhesive. Before use, the Pocket Bag needs to be baked at 60°C for at least 4 hours, and then quickly transferred to a 25°C Class 100 clean glove box as described in step (1) for later use;

[0179] (3) Assembly of symmetrical cells: Using the negative electrode as the electrode, assemble symmetrical cell samples with a single-layer separator in situ in the glove box described in step (1). Each group of samples has 5 parallel samples; use a simple packaging machine to side seal the Pocket bag, inject liquid (300μL) with a pipette, and bottom seal.

[0180] (4) Apply clamps to the assembled symmetrical battery: Place the assembled symmetrical battery in the glove box described in step (1) overnight to allow the electrolyte to fully wet the separator membrane; the next day, apply metal clamps, and control the pressure of the clamps at 0.7 MPa;

[0181] (5) Measurement of electrochemical impedance spectroscopy (EIS):

[0182] Before measurement, place the symmetrical battery in a high and low temperature chamber at 25°C for half an hour and measure the EIS at the set temperature (25°C). (If it is a low temperature (e.g., -25°C to 0°C), the constant temperature time can be extended accordingly, such as about two hours).

[0183] (6) A French Bio-Logic VMP3 electrochemical workstation was used, with a voltage < 5V, a current < 400mA, and a current accuracy of 0.1% * 100μA. During measurement, the EIS measurement conditions were set to a voltage frequency of 1MHz-1kHz, a disturbance voltage of 5MV, and a clamp pressure of 0.7MPa.

[0184] (7) Plot a scatter plot of the real part of the EIS data against the negative imaginary part. At the same time, plot the data of each parallel sample on a single plot. The resulting EIS plot can be used as a comparison of the original EIS data.

[0185] (8) Remove the points in the EIS image obtained in step (7) that are not in the first quadrant to obtain a new EIS image. Perform linear fitting on the scatter points in the first quadrant of the new EIS image to obtain the correlation. Let y = 0 to obtain the x value, which is the required resistance value of the electrolyte in the separator.

[0186] III. Battery DCR

[0187] At 25°C, the battery prepared in Example 1 was charged to 3.8V at a constant current rate of 0.33C, then charged at a constant voltage rate to a current of 0.05C, rested for 5 minutes, and then discharged at a constant current rate of 0.33C to 2V. The constant current discharge capacity was recorded and denoted as the initial capacity C0. Then, the battery cell was rested for 5 minutes, charged to 3.8V at a constant current rate of 0.33C0, charged at a constant voltage rate to a current of 0.05C, rested for 5 minutes, then discharged at a constant current rate of 0.33C0 for 1.5 hours, rested for 30 minutes, and then discharged at a constant current rate of 3C0 for 30 seconds, rested for 5 minutes. The voltage values ​​before and after the constant current discharge at a constant current rate of 1.5C0 were recorded as U1 and U2, respectively. The DCR of the battery cell at 50% SOC was calculated according to the formula DCR=(U1-U2) / 1.5C0.

[0188] IV. Battery capacity retention rate after 500 cycles at 25℃

[0189] At 25°C, the battery prepared in Example 1 was charged to 3.8V with a constant current of 1 / 3C, then charged to a current of 0.05C with a constant voltage of 3.8V, left to rest for 5 minutes, and then discharged to 2.0V with a constant current of 1 / 3C. The resulting discharge capacity was recorded as the initial capacity C0. The above steps were repeated for the same battery, and the discharge capacity Cn of the battery after the nth cycle was recorded. The battery capacity retention rate after each cycle was Pn = (Cn / C0) × 100%. The difference in cycle performance can be reflected by the battery capacity retention rate after 500 cycles.

[0190] Comparative Example 1

[0191] Except for directly using the commercially available PE microporous film from Example 1 as the separator, the preparation and testing were carried out according to the same steps as in Example 1, and the test results are shown in Table 1.

[0192] Comparative Example 2

[0193] Except for the preparation of the binder microparticles for the separator membrane according to the following method, the preparation and testing were carried out in the same manner as in Example 1, and the test results are shown in Table 1.

[0194] Styrene-ethyl acrylate copolymer, used as a polymer binder latex, and polyacrylamide, used as a dispersant, were weighed at a mass ratio of 100:10. Water and the above raw materials were mixed evenly to obtain a binder slurry (solid content 25%). After spray drying (inlet air temperature 115℃, outlet air temperature 68℃, hydraulic pressure 0.3MPa), binder microparticles with a particle size Dv50 of 7.0μm were prepared.

[0195] Examples 2-5

[0196] Except for the mass of each raw material in the preparation process of the binder particles, as shown in Table 1, the preparation and testing were carried out in the same manner as in Example 1, and the test results are shown in Table 1.

[0197] Table 1

[0198]

[0199] Examples 6-8

[0200] Except for the coating density of the binder particles on the separator and the ratio of their projected area to the surface area of ​​the separator, the preparation and testing were carried out in the same manner as in Example 1, as shown in Table 2.

[0201] Table 2

[0202]

[0203] Examples 9-12

[0204] Except for the types of fibrous materials and their diameters and lengths, as shown in Table 3, the preparation and testing were carried out in the same manner as in Example 1, as detailed in Table 3.

[0205] Table 3

[0206]

[0207] Examples 13-14

[0208] Except for the polymer binder latex used in preparing the binder particles, as shown in Table 4, the preparation and testing were carried out according to the same steps as in Example 1, as shown in Table 4.

[0209] Table 4

[0210]

[0211]

[0212] Examples 15-17

[0213] Except for adjusting the particle size Dv50 of the binder particles, which is mainly achieved by adjusting the solid content of the binder slurry and the hydraulic parameters of spray drying as shown in Table 5, the preparation and testing were carried out according to the same steps as in Example 1, as shown in Table 5.

[0214] Table 5

[0215]

[0216] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A battery cell, characterized in that, The battery cell includes a positive electrode, a separator, and a negative electrode. At least one surface of the isolation membrane has adhesive particles; the adhesive particles include fibrous materials and polymer adhesive latex.

2. The battery cell as described in claim 1, characterized in that, The adhesive particles are distributed discontinuously on the surface of the separator.

3. The battery cell as described in claim 1 or 2, characterized in that, For the surface of the isolation membrane containing the adhesive particles, the projected area of ​​the adhesive particles on the isolation membrane surface accounts for 5% to 50% of the surface area of ​​the isolation membrane; the direction of the projection is perpendicular to the isolation membrane surface.

4. The battery cell according to any one of claims 1 to 3, characterized in that, In the adhesive particles, the mass ratio of the fibrous material to the polymer adhesive latex is (20-100):

100.

5. The battery cell according to any one of claims 1 to 4, characterized in that, The morphology of the fibrous material includes at least one selected from the group consisting of rod-shaped, tubular, rod-shaped, and fibrous.

6. The battery cell according to any one of claims 1 to 5, characterized in that, The diameter of the fibrous material is 1–100 nm; and / or, The length of the fibrous material is 0.1–10 μm.

7. The battery cell according to any one of claims 1 to 6, characterized in that, The fibrous material includes at least one of the following: cellulose, lignin, carbon fiber, polyester fiber, polyamide fiber (e.g., aromatic polyamide fiber), and polyacrylonitrile fiber.

8. The battery cell according to any one of claims 1 to 7, characterized in that, The polymer binder latex includes polyacrylate latex.

9. The battery cell as described in claim 8, characterized in that, The polyacrylate latex is a copolymer formed from at least one monomer selected from the group consisting of: methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, butyl acrylate, butyl methacrylate, isooctyl acrylate, isooctyl methacrylate, acrylic acid, methacrylic acid, acrylamide, and styrene.

10. The battery cell according to any one of claims 1 to 9, characterized in that, The adhesive particles also contain a dispersant; the mass ratio of the fibrous material, the polymer adhesive latex, and the dispersant in the adhesive particles is (20-100):100:(2-15).

11. The battery cell according to any one of claims 1 to 10, characterized in that, The binder particles have a unit area weight of 0.5–2.6 g / m² on the release membrane. 2 .

12. The battery cell according to any one of claims 1 to 11, characterized in that, The isolation membrane includes a base membrane and a functional coating disposed on at least one surface of the base membrane, wherein the adhesive microparticles are disposed on the surface of the functional coating; the functional coating contains inorganic particles.

13. A method for preparing a single battery cell, characterized in that, Includes the following steps: A release membrane is provided, at least one surface of which has adhesive particles; the adhesive particles comprise fibrous material and polymeric adhesive latex. A battery cell is prepared by assembling the positive electrode, the negative electrode, and the separator.

14. The preparation method according to claim 13, characterized in that, The particle size Dv50 of the binder microparticles is 5–15 μm.

15. The preparation method according to claim 14, characterized in that, The glass transition temperature (Tg) of the binder particles is less than 60°C.

16. A battery device, characterized in that, Includes the battery cell according to any one of claims 1 to 12, or the battery cell prepared by the preparation method according to any one of claims 13 to 15.

17. An electrical device, characterized in that, Includes the battery device as described in claim 16.

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