A battery, a preparation method thereof, a battery pack, and a power utilization device

Abstract

This invention provides a battery, its manufacturing method, a battery pack, and an electrical device. The battery includes a cell and an encapsulation material on the surface of the cell, extending from the side closest to the cell to the side furthest away. The encapsulation material comprises a composite ceramic layer, a first polymer layer, and a second polymer layer stacked sequentially. The composite ceramic layer includes a ceramic material and a third polymer. The third polymer includes one or more of polyolefin, polyacrylate, polyurethane, and polyimide. The first polymer layer includes one or more of polyolefin, polyacrylate, and polyurethane. The second polymer layer includes a second polymer, which comprises resin structural units, including one or more of epoxy, polyester, phenolic, vinyl ester, and acrylic structural units. This invention can improve the long-term cycle stability of the battery and significantly reduce the risk of battery thermal runaway.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, specifically relating to a battery and its preparation method, battery pack and electrical equipment. Background Technology

[0002] Driven by market demand for high-energy-density, high-safety, and long-life batteries, all-solid-state batteries are considered a revolutionary technology to accelerate the popularization of electric vehicles. However, existing solid-state batteries still have significant shortcomings in long-term cycle stability and safety performance, making it difficult to meet the application requirements of high-reliability batteries in fields such as new energy vehicles and energy storage systems. Specifically, after hundreds of charge-discharge cycles, existing solid-state batteries are prone to problems such as electrode pulverization and active material shedding, leading to rapid capacity decay, significantly increased internal resistance, and a drastically shortened cycle life, making them unsuitable for long-term service scenarios. Furthermore, the battery's safety protection system design has deficiencies. When the battery encounters abnormal conditions such as overcharging, short circuits, or high temperatures, the heat inside the cell cannot be quickly dissipated, easily triggering a chain reaction such as separator shrinkage and short circuits between the positive and negative electrodes, which can induce thermal runaway, leading to battery fires and explosions, posing a high safety risk. Therefore, improving the long-term cycle stability and safety performance of batteries has become a key focus of current battery research and development. Summary of the Invention

[0003] This invention provides a battery, its preparation method, battery pack, and electrical device. The battery achieves lightweight packaging while possessing excellent long-term cycle stability and high safety, significantly reducing the risk of thermal runaway and providing highly reliable protection for the battery cell.

[0004] This invention provides a battery, including a battery cell and an encapsulation material present on the surface of the battery cell; from the side closest to the battery cell to the side furthest from the battery cell, the encapsulation material includes a composite ceramic layer, a first polymer layer, and a second polymer layer stacked sequentially; the composite ceramic layer includes a ceramic material and a third polymer; the third polymer includes one or more of polyolefin, polyacrylate, polyurethane, and polyimide; the first polymer layer includes one or more of polyolefin, polyacrylate, and polyurethane; the second polymer layer includes a second polymer, the second polymer including resin structural units, the resin structural units including one or more of epoxy structural units, polyester structural units, phenolic structural units, vinyl ester structural units, and acrylic structural units.

[0005] According to one embodiment of the present invention, the mass ratio of the ceramic material to the third polymer is 10:(1-5); and / or, the ceramic material includes one or more of alumina, zirconium oxide, boehmite, lithium lanthanum zirconium oxide, lithium titanium aluminum phosphate, titanium dioxide, silicon carbide, silicon oxide, and silicon nitride; and / or, the particle size D50 of the ceramic material is 0.1μm-3μm.

[0006] According to one embodiment of the present invention, the second polymer further includes a curing agent structural unit, the curing agent structural unit including an amine structural unit and / or an amide structural unit; preferably, the mass ratio of the resin structural unit to the curing agent structural unit is 10:(1~4).

[0007] According to one embodiment of the present invention, the polyolefin comprises polyethylene and / or polypropylene; and / or, the polyacrylate comprises polymethyl acrylate.

[0008] According to one embodiment of the present invention, the thickness of the composite ceramic layer is 30μm-100μm, preferably 50μm-80μm; and / or, the thickness of the first polymer layer is 40μm-100μm; and / or, the thickness of the second polymer layer is 50μm-100μm.

[0009] According to one embodiment of the present invention, the elastic modulus of the composite ceramic layer is 2GPa-6GPa, preferably 3GPa-5GPa; and / or, the pull-out force between the two first polymer layers is 100N / 15mm-200N / 15mm; and / or, the battery is a solid-state battery.

[0010] This invention also provides a method for preparing the above-mentioned battery, comprising the following steps: S1, coating a first slurry containing ceramic material and a third polymer onto the surface of a battery cell to form a composite ceramic layer, thereby obtaining a first intermediate battery cell; S2, performing a hot-pressing composite treatment on the first polymer and the first intermediate battery cell to form a first polymer layer on the side of the composite ceramic layer opposite to the battery cell; S3, coating a second raw material containing a second polymer monomer onto the side of the first polymer layer opposite to the composite ceramic layer, and subjecting it to a curing reaction to form a second polymer layer, thereby obtaining the battery.

[0011] According to one embodiment of the present invention, the curing reaction temperature is 25℃-300℃, and the curing reaction time is 10min-120min.

[0012] Embodiments of the present invention also provide a battery pack comprising at least two batteries as described above that are interconnected.

[0013] This invention also provides an electrical device, including the battery or battery pack described above.

[0014] This invention provides a battery, its manufacturing method, a battery pack, and an electrical device, including a battery cell and an encapsulation material on the surface of the battery cell. From the side closest to the battery cell to the outside, the encapsulation material includes a composite ceramic layer, a first polymer layer, and a second polymer layer stacked sequentially. The composite ceramic layer contains a ceramic material and a third polymer, which includes one or more of polyolefin, polyacrylate, polyurethane, and polyimide. The composite ceramic layer, through the rigidity of the ceramic material and the adhesiveness of the third polymer, imparts excellent flatness and mechanical strength to the encapsulation material, ensuring uniform stress on the battery cell, preventing structural damage, and improving battery capacity consistency and cycle stability. Furthermore, the ceramic material has excellent heat resistance, preventing the encapsulation material from failing under high-temperature processing conditions. The first polymer layer includes one or more of polyolefin, polyacrylate, and polyurethane. The first polymer layer forms a sealing barrier with a dense structure, isolating moisture, inhibiting side reactions, preventing battery cell capacity decay and internal resistance increase, and improving the long-term cycle performance of the battery. The second polymer layer includes resin structural units, which include a second polymer, which includes one or more of epoxy structural units, polyester structural units, phenolic structural units, vinyl ester structural units, and acrylic structural units. The second polymer layer combines high temperature resistance and moisture resistance, effectively blocking heat diffusion and flame spread when the battery cell faces the risk of thermal runaway, significantly improving the safety performance of the battery cell. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the battery structure in one embodiment of the present invention;

[0016] Figure 2 This is a schematic diagram of the structure of the first intermediate battery cell in steps S1-5 of Embodiment 1 of the present invention.

[0017] Explanation of reference numerals in the attached figures:

[0018] 1-Composite ceramic layer; 2-First polymer layer; 3-Second polymer layer; 4-Battery cell; 5-Aluminum foil; 6-Positive electrode active material layer; 7-Solid electrolyte layer; 8-Negative electrode active material layer; 9-Copper foil; 10-Encapsulation material. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below. The specific embodiments listed below are merely descriptions of the principles and features of the present invention, and the examples are only for explaining the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In related technologies, battery packaging materials still have the following shortcomings: First, they lack high-temperature resistance. Aluminum foil and insulating layers are prone to melting and deformation under extreme high-temperature environments, which can easily lead to short circuits between the positive and negative electrodes and cause battery thermal runaway. Second, their sealing and protection performance is poor. Moisture in the air can easily penetrate into the cell, accelerating the corrosion of electrode materials and reducing the long-term cycle stability of the battery. Third, the bottleneck of lightweighting is prominent. In order to improve the packaging strength, it is necessary to add metal structural components (such as aluminum foil) or thicken the packaging material, which leads to an increase in the overall weight of the battery.

[0021] In view of this, the present invention provides an encapsulation material, such as Figure 1 As shown, it includes: a battery cell 4 and an encapsulation material 10 present on the surface of the battery cell 4; from the side closest to the battery cell 4 to the outside, the encapsulation material 10 includes a composite ceramic layer 1, a first polymer layer 2 and a second polymer layer 3 stacked sequentially; the composite ceramic layer 1 includes a ceramic material and a third polymer; the third polymer includes one or more of polyolefin, polyacrylate, polyurethane and polyimide; the first polymer layer 2 includes one or more of polyolefin, polyacrylate and polyurethane; the second polymer layer 3 includes a second polymer, the second polymer includes resin structural units, the resin structural units include one or more of epoxy structural units, polyester structural units, phenolic structural units, vinyl ester structural units and acrylic structural units.

[0022] The battery of this invention achieves lightweight packaging while possessing excellent long-term cycle stability and high safety, significantly reducing the risk of thermal runaway and providing highly reliable protection for the battery cell. The reasons are as follows: 1) The composite ceramic layer utilizes the rigidity of the ceramic material and the adhesiveness of the third polymer to impart excellent flatness and mechanical strength to the packaging material. During isostatic pressing and performance testing of the battery cell, this composite ceramic layer ensures uniform stress distribution across the large surface area of ​​the cell, effectively preventing internal structural damage caused by localized stress concentration, thereby improving the capacity consistency and cycle stability of the cell. Simultaneously, the ceramic material possesses excellent heat resistance, allowing the composite ceramic layer to withstand high-temperature processing conditions without decomposition or melting. 2) The first polymer layer has excellent formability and chemical corrosion resistance, allowing it to adhere tightly to the surface of the composite ceramic layer and form a reliable sealing structure. This effectively inhibits moisture intrusion into the cell, thereby suppressing moisture-induced internal side reactions, preventing capacity decay and increased internal resistance, and improving the long-term stability of the cell. 3) The second polymer layer possesses excellent high-temperature resistance and moisture resistance, effectively blocking heat diffusion and flame spread under conditions of potential thermal runaway, thus improving cell safety. 4) The use of a multi-layer encapsulation material composed of a composite ceramic layer, a first polymer layer, and a second polymer layer reduces the use of high-area-density structural components, achieving lightweight encapsulation materials. Therefore, the encapsulation material possesses excellent mechanical strength, sealing properties, and high-temperature resistance, effectively improving the long-term cycle stability of the battery, significantly reducing the risk of battery thermal runaway, and thus achieving high-reliability protection for the cell.

[0023] In this embodiment of the invention, the second polymer is polymerized from raw materials including a second polymeric monomer, and has a resin structural unit formed by polymerizing a resin monomer, which serves as a repeating unit of the polymeric chain segment in the second polymer.

[0024] In some implementations, the polyolefin includes polyethylene and / or polypropylene.

[0025] In some embodiments, the polyacrylate includes polymethyl acrylate.

[0026] In some embodiments, the epoxy structural unit includes one or more of bisphenol A type epoxy resin structural units, bisphenol F type epoxy resin structural units, and diglycidyl phthalate structural units.

[0027] In some embodiments, the polyester structural unit includes one or more of polyethylene terephthalate structural units, polybutylene terephthalate structural units, and polyethylene adipate structural units.

[0028] In some embodiments, the vinyl ester structural unit includes bisphenol A type vinyl ester structural unit and / or phenolic type vinyl ester resin structural unit.

[0029] In some embodiments, the mass ratio of ceramic material to third polymer is 10:(1-5), which is conducive to achieving synergy and balance of the performance of the two components. This fully utilizes the heat resistance and rigidity advantages of ceramic material, while also fully leveraging the bonding and film-forming properties of third polymer, thus ensuring the structural integrity of the composite ceramic layer.

[0030] For example, the mass ratio of the ceramic material to the third polymer can be 10:1, 10:2, 10:3, 10:4, or 10:5, etc.

[0031] In some embodiments, the ceramic material includes one or more of alumina, zirconium oxide, boehmite, lithium lanthanum zirconium oxide, lithium titanium aluminum phosphate, titanium dioxide, silicon carbide, silicon oxide, and silicon nitride. These ceramic materials all possess high hardness, high melting point, and low thermal conductivity, which are beneficial for further improving the mechanical strength, deformation resistance, and high-temperature resistance of the composite ceramic layer.

[0032] In some embodiments, the particle size D50 of the ceramic material is 0.1μm-3μm, which is beneficial for constructing a dense packing structure, enhancing the barrier and protective performance of the composite ceramic layer, while also improving the compatibility between the ceramic material and the third polymer, and preventing delamination and cracking of the composite ceramic layer.

[0033] For example, the particle size D50 of the ceramic material can be 0.1μm, 0.3μm, 0.5μm, 0.8μm, 1μm, 1.2μm, 1.5μm, 1.8μm, 2μm, 2.3μm, 2.5μm, 2.8μm or 3μm, etc.

[0034] In this embodiment of the invention, the particle size D50 of the ceramic material refers to the volumetric particle size D50, which is the particle size value corresponding to the cumulative particle size distribution based on volume reaching 50%. The particle size D50 of the ceramic material can be determined using conventional particle size testing instruments in the art, such as a laser particle size analyzer.

[0035] In some embodiments, the composite ceramic layer further includes an adhesive, which includes, but is not limited to, water-based adhesives such as acrylics, specifically one or more of butyl acrylate, methyl methacrylate, and sodium carboxymethyl cellulose.

[0036] In some embodiments, the mass ratio of binder to ceramic material in the composite ceramic layer is (0.1-0.3):10.

[0037] For example, the mass ratio of binder to ceramic material in the composite ceramic layer can be 0.1:10, 0.15:10, 0.2:10, 0.25:10 or 0.3:10, etc.

[0038] It is understood that when the resin structural unit includes one or more of epoxy structural units, polyester structural units, phenolic structural units, and vinyl ester structural units, the second polymer also includes a curing agent structural unit.

[0039] In some embodiments, the mass ratio of resin structural units to curing agent structural units is 10:(1~4). This is beneficial for improving the sealing and high-temperature resistance of the second polymer layer while also improving its flexibility, thereby further enhancing the protective stability of the second polymer layer under battery charge-discharge cycles and thermal runaway risk conditions.

[0040] For example, the mass ratio of resin structural units to curing agent structural units can be 10:1, 10:2, 10:2.5, 10:3, 10:3.5 or 10:4, etc.

[0041] In this embodiment of the invention, the curing agent structural units include amine structural units and / or amide structural units. This facilitates the construction of a dense cross-linked network structure, further improving the high-temperature resistance and sealing barrier properties of the second polymer layer.

[0042] In some embodiments, the amine structural unit includes one or more of the following: ethylenediamine structural unit, phthalic anhydride structural unit, dicyandiamide structural unit, hexamethylenetetramine structural unit, diaminodiphenyl sulfone structural unit, polyamide structural unit, and diaminodiphenyl sulfone structural unit.

[0043] In some embodiments, the amide structural unit includes a polyamide structural unit.

[0044] In some embodiments, when the resin structural unit includes an acrylic structural unit, acrylic monomers are polymerized under the action of an initiator to form the acrylic structural unit.

[0045] In some embodiments, the thickness of the composite ceramic layer is 30μm-100μm, preferably 50μm-80μm. This is beneficial for improving the high temperature resistance and moisture resistance of the composite ceramic layer while avoiding internal stress concentration due to excessive thickness of the composite ceramic layer. This prevents the composite ceramic layer from cracking or peeling during the deformation of the battery cell and ensures the integrity of the packaging material.

[0046] For example, the thickness of the composite ceramic layer can be 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm or 100μm, etc.

[0047] In this embodiment of the invention, the thickness of the composite ceramic layer can be controlled by conventional means in the art, such as adjusting the coating density of the first slurry described below.

[0048] In this embodiment of the invention, by adjusting the thickness of the first polymer layer and the second polymer layer, the long-term cycle stability and safety of the battery are further improved, the risk of thermal runaway is reduced, and high-reliability protection of the battery cell is achieved. In some embodiments, the thickness of the first polymer layer is 40μm-100μm, and the thickness of the second polymer layer is 40μm-100μm.

[0049] For example, the thickness of the first polymer layer can be 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm, etc.

[0050] For example, the thickness of the second polymer layer can be 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm, etc.

[0051] In this embodiment of the invention, the thickness of the first polymer layer can be controlled by conventional means in the art, such as adjusting the mold pressing gap, pressing pressure, or pressing tightness.

[0052] In this embodiment of the invention, the thickness of the second polymer layer can be controlled by conventional means in the art, such as adjusting the mold pressing gap, pressing pressure, or pressing tightness.

[0053] In some embodiments, the elastic modulus of the composite ceramic layer is 2 GPa-6 GPa, preferably 3 GPa-5 GPa. This is beneficial for improving the mechanical properties of the packaging material, allowing the packaging material to better adapt to the volume deformation of the battery cell, and preventing cracking of the packaging material.

[0054] For example, the elastic modulus of the composite ceramic layer can be 2 GPa, 2.5 GPa, 3 GPa, 3.5 GPa, 4 GPa, 4.5 GPa, 5 GPa, 5.5 GPa or 6 GPa, etc.

[0055] In this embodiment of the invention, the elastic modulus of the composite ceramic layer can be determined with reference to GB / T 1040.1-2022. The elastic modulus is obtained by measuring the stress-strain curve of the sample under tensile force and taking the slope of the initial straight line segment of the stress-strain curve.

[0056] In some embodiments, the pull-out force between the two first polymer layers is 100N / 15mm-200N / 15mm. This helps to further improve the density and barrier properties of the encapsulation material.

[0057] For example, the pull-out force between the two first polymer layers can be 100N / 15mm, 130N / 15mm, 160N / 15mm, 180N / 15mm or 200N / 15mm, etc.

[0058] In this embodiment of the invention, the pull-out force between the two first polymer layers can be measured using the lithium battery industry pull-out force test standard GB / T 33972-2017.

[0059] In some implementations, the battery is a solid-state battery.

[0060] The present invention also provides a method for preparing the above-mentioned battery, comprising the following steps: S1, coating a first slurry containing ceramic material and a third polymer onto the surface of the battery cell to form a composite ceramic layer, thereby obtaining a first intermediate battery cell; S2, performing a hot-pressing composite treatment on the first polymer and the first intermediate battery cell to form a first polymer layer on the side of the composite ceramic layer away from the battery cell; S3, coating a second raw material containing a second polymer monomer onto the side of the first polymer layer away from the composite ceramic layer, and subjecting it to a curing reaction to form a second polymer layer, thereby obtaining the battery.

[0061] In some embodiments, the first slurry further includes a first solvent, which includes one or more of water, N-methylpyrrolidone (NMP), xylene, anisole, butyl butyrate, isobutyl isobutyrate, N,N-dimethylformamide (DMF), and acetonitrile.

[0062] In some embodiments, the solid content of the first slurry is 30%-90%, preferably 40%-80%. This facilitates good fluidity of the first slurry, resulting in good smoothness during coating and further improving cell performance.

[0063] In some embodiments, the process of coating a first slurry containing ceramic materials and a third polymer onto the surface of the battery cell to form a composite ceramic layer and obtain a first intermediate battery cell includes: coating the first slurry containing ceramic materials and a third polymer onto the surface of the battery cell, drying and rolling to form a composite ceramic layer, and obtaining a first intermediate battery cell.

[0064] In some implementations, the linear pressure of the roll forming process is 0.5T / cm to 3T / cm.

[0065] In this embodiment of the invention, the thickness of the composite ceramic layer is controlled to 30μm-100μm by adjusting the linear pressure of the roll forming process.

[0066] In some embodiments, the hot-pressing composite process in step S2 includes a thermoplastic molding process.

[0067] In some embodiments, the hot-pressing composite treatment temperature is 100℃-350℃, preferably 150℃-300℃, and the hot-pressing composite treatment time is 30s-300s. This facilitates a tight bond between the first polymer layer and the composite ceramic layer.

[0068] In this embodiment of the invention, the curing reaction temperature is 25℃-300℃, and the curing reaction time is 10min-120min. This facilitates the full progress of the curing reaction, forming a uniform and dense three-dimensional cross-linked network, thereby further improving the long-term cycle stability and safety of the battery.

[0069] For example, the curing temperature can be 25°C, 50°C, 70°C, 100°C, 125°C, 150°C, 200°C, 250°C, or 300°C, etc.

[0070] For example, the curing reaction time can be 10 min, 20 min, 30 min, 40 min, 60 min, 80 min, 100 min or 120 min, etc.

[0071] In some embodiments, the second polymerizing monomer includes one or more of epoxy resin, polyester resin, phenolic resin, vinyl ester resin, and acrylic resin.

[0072] In some embodiments, when the second polymerizing monomer includes epoxy resin, polyester resin, phenolic resin, or vinyl ester resin, the second raw material also includes a curing agent. The second polymerizing monomer undergoes a crosslinking reaction (i.e., a curing reaction) under the action of the curing agent to form a second polymer with a crosslinked network structure.

[0073] In some embodiments, the curing agent includes one or more of ethylenediamine, phthalic anhydride, dicyandiamide, methyl ethyl ketone peroxide, hexamethylenetetramine, diaminodiphenyl sulfone, and polyamide.

[0074] In some embodiments, when the second polymerizing monomer comprises an acrylic resin, the second raw material also includes an initiator.

[0075] This invention does not impose any particular limitation on the type of initiator used to initiate the polymerization reaction of acrylic resin, and conventional free radical polymerization initiators in the art can be used. Exemplary initiators include, but are not limited to, peroxide initiators, specifically methyl ethyl ketone peroxide (MEKP), and may further include benzoyl peroxide (BPO), cyclohexanone peroxide, dicumyl peroxide, etc.; the amount of initiator added is 0.5% to 5% of the total mass of acrylic resin monomers.

[0076] Generally, a battery cell includes a positive electrode, a negative electrode, and a solid electrolyte layer located between the positive and negative electrodes. The battery cell can be a laminated cell, meaning it is composed of alternating layers of the positive electrode, solid electrolyte layer, and negative electrode; or it can be a wound cell, meaning it is composed of layers of the positive electrode, solid electrolyte layer, and negative electrode that are then wound together.

[0077] This invention also provides a method for preparing a solid-state battery, comprising the following steps: sequentially stacking a positive electrode sheet, a solid electrolyte layer, and a negative electrode sheet to obtain a stacked cell. After the cell stacking is completed, the cell is pressed into shape under a certain pressure, and then tabs are welded to obtain a solid-state battery.

[0078] Generally, a positive electrode sheet includes a positive current collector and a positive active material layer located on at least one side of the positive current collector. The positive active material layer includes a positive active substance, a positive binder, and a positive conductive agent. In the positive active material layer, the mass percentage of the positive binder is 1% to 2.5%, for example, it can be 1%, 1.3%, 1.5%, 1.7%, 1.9%, 2.1%, 2.3%, or 2.5%, etc. The mass percentage of the positive active substance can be 70% to 99%, for example, 70%, 75%, 80%, 85%, 90%, 93%, 95%, 97%, 99%, or any combination thereof. The mass percentage of the positive conductive agent can be 1% to 6%, for example, 1%, 2%, 3%, 4%, 5%, 6%, or any combination thereof.

[0079] The positive electrode binder in the positive electrode active material layer can be any one or a combination of several conventional binders, including polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene binary copolymer, PVDF-hexafluoropropylene binary copolymer, PVDF-tetrafluoroethylene-hexafluoropropylene ternary copolymer, and fluorinated acrylic resins. The positive electrode active material in the positive electrode active material layer can be a widely used positive electrode active material in the art, including but not limited to lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium manganese oxide, nickel-cobalt-manganese ternary materials, nickel-cobalt-aluminum ternary materials, lithium iron phosphate, lithium nickel manganese oxide, and lithium-rich manganese-based materials. The aforementioned positive electrode active materials can be used alone or in combination of two or more.

[0080] In this embodiment of the invention, the positive current collector can be aluminum foil.

[0081] In this embodiment of the invention, the positive electrode sheet can be prepared by conventional methods in the art, such as by coating. Specifically, the positive electrode active material, positive electrode conductive agent, positive electrode binder, and other components used to form the positive electrode material layer can be dispersed in a positive electrode solvent (i.e., homogenized) to prepare a positive electrode slurry. The positive electrode solvent may include, for example, toluene. This slurry is then coated onto the surface of the positive electrode current collector, and after drying, rolling, and other processes, the positive electrode sheet is obtained. The coating, drying, and rolling processes involved are conventional operations for preparing positive electrode sheets using the coating method, and are not particularly limited thereto.

[0082] Generally, a negative electrode sheet includes a negative current collector and a negative active material layer located on at least one side of the negative current collector. The negative active material layer includes a negative active substance, a negative binder, and a negative conductive agent. In the negative active material layer, the mass percentage of the negative binder is 1% to 2.5%, for example, it can be 1%, 1.3%, 1.5%, 1.7%, 1.9%, 2.1%, 2.3%, or 2.5%, etc. The mass percentage of the negative active substance can be 70% to 99%, for example, 70%, 75%, 80%, 85%, 90%, 93%, 95%, 97%, 99%, or any combination thereof. The mass percentage of the negative conductive agent can be 1% to 6%, for example, 1%, 2%, 3%, 4%, 5%, 6%, or any combination thereof.

[0083] In this embodiment of the invention, the negative electrode binder in the negative electrode active material layer may include at least one of polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), sodium carboxymethyl cellulose (CMC), tetrafluoroethylene and its multi-component copolymers, polyvinylidene fluoride and its multi-component copolymers, polyolefins and their multi-component copolymers (e.g., polyethylene, polypropylene, polyethylene-polyethylene glycol block copolymers, etc.), polyvinyl alcohol, polyurethane, polyvinyl chloride, polyvinylpyrrolidone, nitrile rubber, polyacrylic acid (PAA), and polyacrylates (such as sodium polyacrylate).

[0084] Furthermore, the negative electrode active material can be a conventional negative electrode active material in the art. For example, conventional negative electrode active materials may include one or more of graphite, pure silicon, and silicon carbide, but are not limited thereto.

[0085] The embodiments of the present invention may employ conventional negative electrode current collectors in the art, for example, negative electrode current collectors include copper foil.

[0086] In this embodiment of the invention, the negative electrode sheet can be prepared by conventional methods in the art, such as by coating. Specifically, the components used to form the negative electrode active layer, such as the negative electrode active material, negative electrode conductive agent, and negative electrode binder, can be dispersed in the negative electrode solvent toluene (i.e., homogenized) to prepare a negative electrode slurry. This slurry is then coated onto the surface of the negative electrode current collector, and after drying, rolling, and other processes, the negative electrode sheet is obtained. The coating, drying, and rolling processes involved are conventional operations for preparing negative electrode sheets using the coating method, and are not particularly limited thereto.

[0087] In addition, the positive electrode conductive agent and the negative electrode conductive agent can be conventional conductive materials in the art. For example, the positive electrode conductive agent may include one or more of carbon black, carbon nanotubes (CNT), acetylene black, graphene, Ketjen black, and carbon fiber, and the negative electrode conductive agent may include one or more of carbon black, carbon nanotubes (CNT), acetylene black, graphene, Ketjen black, and carbon fiber.

[0088] In this embodiment of the invention, the solid electrolyte layer comprises a solid electrolyte and a first binder. The invention does not specifically limit the type of solid electrolyte, but may include, however, one or more of perovskite electrolytes, garnet electrolytes, NASICON electrolytes, LISICON electrolytes, and sulfide electrolytes. The invention also does not specifically limit the type of the first binder, but may include, however, at least one of polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), sodium carboxymethyl cellulose (CMC), tetrafluoroethylene and its multi-component copolymers, polyvinylidene fluoride and its multi-component copolymers, polyolefins and their multi-component copolymers (e.g., polyethylene, polypropylene, polyethylene-polyethylene glycol block copolymers, etc.), polyvinyl alcohol, polyurethane, polyvinyl chloride, polyvinylpyrrolidone, nitrile rubber, polyacrylic acid (PAA), and polyacrylates (such as sodium polyacrylate). The mass ratio of the solid electrolyte to the first binder is (80~95):1.

[0089] This invention provides a battery pack comprising at least two of the aforementioned batteries. This battery pack has advantages corresponding to the aforementioned batteries, which will not be elaborated further.

[0090] Generally, a battery pack includes multiple batteries as individual cells, which are connected to form the battery pack. These batteries can be electrically connected using methods conventional in the art, such as series connection, parallel connection, or a combination of these connection methods, without any particular limitation.

[0091] The present invention also provides an electrical device including the aforementioned battery pack. This electrical device has advantages corresponding to the aforementioned battery, which will not be elaborated further.

[0092] The electrical equipment used in the embodiments of the present invention can be conventional electrical equipment in the art, such as power equipment (e.g., electric vehicles, electric cars), electronic equipment (e.g., mobile phones, tablets, laptops, digital cameras, etc.), wearable devices (e.g., watches, bracelets, VR glasses, etc.), energy storage power stations, etc., and there are no particular limitations on this.

[0093] The present invention will be further described below through specific embodiments.

[0094] Example 1

[0095] The preparation method of the all-solid-state battery in this embodiment includes the following steps:

[0096] S1-1. Preparation of the positive electrode sheet: The positive electrode active material NCM622, the positive electrode conductive agent conductive carbon black, and the positive electrode binder polyvinylidene fluoride are dispersed in the positive electrode solvent N-methylpyrrolidone at a mass ratio of 93:2:5 to form a positive electrode slurry; the positive electrode slurry is coated on both sides of the positive electrode current collector aluminum foil, dried, rolled, and cut to form a positive electrode active material layer on both sides of the aluminum foil, thus obtaining the positive electrode sheet;

[0097] S1-2, Preparation of negative electrode sheet: The negative electrode active material graphite, the negative electrode conductive agent conductive carbon black and the negative electrode binder polyvinylidene fluoride are dispersed in the negative electrode solvent N-methylpyrrolidone at a mass ratio of 91:3:6 to form a negative electrode slurry. The negative electrode slurry is coated on one side of the negative electrode current collector copper foil, and after drying and rolling, a negative electrode active material layer is formed to obtain the negative electrode sheet.

[0098] S1-3 Preparation of solid electrolyte layer: LISICON electrolyte powder and electrolyte binder styrene-butadiene rubber (SBR) are dispersed in electrolyte solvent NMP at a mass ratio of 90:10 to form electrolyte slurry. The electrolyte slurry is coated on the side of the negative electrode active material layer away from the copper foil. After drying and slitting, a solid electrolyte layer is formed to obtain the composite negative electrode sheet.

[0099] S1-4. Preparation of the composite ceramic layer: Alumina ceramic material with a particle size D50 of 0.2 μm, polyimide, and sodium carboxymethyl cellulose binder are mixed in a mass ratio of 10:2:0.1 and dispersed in the first solvent N-methylpyrrolidone (NMP) to obtain a first slurry with a solid content of 60 wt%. The first slurry is coated on the side of the copper foil in the above-mentioned composite negative electrode sheet away from the negative electrode active material layer, dried at 120°C, and rolled under a linear pressure of 5 T / cm to form a composite ceramic layer with a thickness of 50 μm, thus obtaining a negative electrode sheet containing a composite ceramic layer.

[0100] S1-5, Cell Assembly: The above-mentioned negative electrode sheet containing the composite ceramic layer and the above-mentioned positive electrode sheet are stacked alternately, with the composite ceramic layer of the negative electrode sheet placed on the outermost side of the cell, to obtain the first intermediate cell. For example... Figure 2 As shown, the first intermediate cell comprises, in sequence, a composite ceramic layer 1, a copper foil 9, a negative electrode active material layer 8, a solid electrolyte layer 7, a positive electrode active material layer 6, an aluminum foil 5, a positive electrode active material layer 6, a solid electrolyte layer 7, a negative electrode active material layer 8, a copper foil 9, and the composite ceramic layer 1. After encapsulation in an aluminum-plastic film, it undergoes isostatic pressing, and then the aluminum-plastic film is disassembled to obtain the isostatically pressed first intermediate cell.

[0101] S1-6, Preparation of the first polymer layer: PP particles (weight-average molecular weight of...) are... The first intermediate battery cell, after being isostatically pressed, is placed into a mold and heated to 150°C. The first intermediate battery cell is then placed into the mold for compression molding and sealing. The heat preservation time is 60 seconds to obtain the second intermediate battery cell.

[0102] S1-7. Preparation of the second polymer layer: Bisphenol A diglycidyl ether and diaminodiphenyl sulfone are mixed at a mass ratio of 10:3.5 to obtain a mixed adhesive. Then, the second intermediate battery cell is placed in a mold, and the above mixed adhesive is poured in and uniformly impregnated. The mixture is heated to 200°C under a vacuum degree ≤0.1Pa and kept at that temperature for 2 hours to carry out the curing reaction, thus obtaining the battery.

[0103] Example 2

[0104] The process is basically the same as in Example 1, except that in the preparation of the composite ceramic layer, the coating density of the first slurry is adjusted, and a 120°C drying and 5kN / cm linear pressure rolling process is used to obtain a composite ceramic layer with a thickness of 30μm.

[0105] Example 3

[0106] The process is basically the same as in Example 1, except that during the preparation of the first polymer layer, the tightness of the mold pressing is adjusted to form a first polymer layer with a thickness of 20 μm.

[0107] Example 4

[0108] The process is basically the same as in Example 1, except that during the preparation of the second polymer layer, the tightness of the mold pressing is adjusted to form a second polymer layer with a thickness of 50 μm.

[0109] Example 5

[0110] The process is basically the same as in Example 1, except that in the preparation of the composite ceramic layer, the ceramic material is replaced by silicon dioxide in equal amounts with alumina.

[0111] Example 6

[0112] The process is basically the same as in Example 1, except that in the preparation of the composite ceramic layer, the third polymer is replaced by an equal amount of PP instead of polyimide.

[0113] Example 7

[0114] The process is basically the same as in Example 1, except that PP is replaced with PE in equal amounts during the preparation of the first polymer layer.

[0115] Example 8

[0116] The process is basically the same as in Example 1, except that in the preparation of the second polymer layer, bisphenol A diglycidyl ether and polyamide are mixed in a mass ratio of 6:4 to obtain a mixed adhesive.

[0117] Example 9

[0118] The process is basically the same as in Example 1, except that in the preparation of the composite ceramic layer, the surface density of the first slurry coating is adjusted, and a 120°C drying and 5kN / cm linear pressure rolling process is used to obtain a composite ceramic layer with a thickness of 100μm.

[0119] Example 10

[0120] The process is basically the same as in Example 1, except that in the preparation of the composite ceramic layer, the surface density of the first slurry coating is adjusted, and a composite ceramic layer with a thickness of 80 μm is obtained by combining drying at 120°C and rolling with a linear pressure of 5 kN / cm.

[0121] Example 11

[0122] The process is basically the same as in Example 1, except that in the preparation of the composite ceramic layer, the surface density of the first slurry coating is adjusted, and a 120°C drying and 5kN / cm linear pressure rolling process is used to obtain a composite ceramic layer with a thickness of 120μm.

[0123] Example 12

[0124] The process is basically the same as in Example 1, except that in the preparation of the composite ceramic layer, the surface density of the first slurry coating is controlled, and a 120°C drying and 5kN / cm linear pressure rolling process is used to obtain a composite ceramic layer with a thickness of 20μm.

[0125] Example 13

[0126] The process is basically the same as in Example 1, except that in the preparation of the composite ceramic layer, alumina, polyimide and sodium carboxymethyl cellulose ceramic materials with a particle size D50 of 0.2 μm are mixed in a mass ratio of 10:5:0.1 and dispersed in the first solvent NMP to obtain a first slurry with a solid content of 60 wt%.

[0127] Example 14

[0128] The process is basically the same as in Example 1, except that in the preparation of the composite ceramic layer, alumina, polyimide and sodium carboxymethyl cellulose ceramic materials with a particle size D50 of 0.2 μm are mixed in a mass ratio of 10:6:0.1 and dispersed in the first solvent NMP to obtain a first slurry with a solid content of 60 wt%.

[0129] Comparative Example 1

[0130] It is basically the same as Example 1, except that the preparation of the second polymer layer in steps S1-7 was not performed.

[0131] Comparative Example 2

[0132] It is basically the same as Example 1, except that the preparation of the first polymer layer in steps S1-6 was not performed.

[0133] Comparative Example 3

[0134] It is basically the same as Example 1, except that the composite ceramic layer in steps S1-4 was not prepared.

[0135] Comparative Example 4

[0136] The process is basically the same as in Example 1, except that a composite ceramic layer, a second polymer layer, and a first polymer layer are sequentially stacked on the surface of the battery cell from the side closest to the cell to the outside. That is, steps S1-6 and S1-7 are different, and specifically include the following steps:

[0137] S1-6. Preparation of the second polymer layer: Epoxy resin and diaminodiphenyl sulfone are mixed at a mass ratio of 10:3.5 to obtain a mixed adhesive. Then, the first intermediate battery cell is placed in a mold, and the above mixed adhesive is poured in to uniformly impregnate it. The mixture is heated to 200°C under vacuum and kept at that temperature for 2 hours to carry out the curing reaction, thus obtaining the third intermediate battery cell.

[0138] S1-7 Preparation of the first polymer layer: PP particles are placed in a mold and heated to 150°C. The third intermediate cell after isostatic pressing is then placed in the mold for compression molding and sealing. The heat preservation time is 60s to obtain the battery.

[0139] Comparative Example 5

[0140] The process is basically the same as in Example 1, except that no ceramic material is added in steps S1-4. Specifically, the process includes the following steps: dispersing polyimide in the first solvent NMP to obtain a first slurry with a solid content of 60wt%; coating the first slurry onto the side of the copper foil in the above-mentioned composite negative electrode sheet away from the negative electrode active material layer; drying at 120°C; and rolling under a linear pressure of 5T / cm to form a third polymer layer with a thickness of 50μm.

[0141] Table 1

[0142]

[0143]

[0144] The batteries in the above embodiments and comparative examples were tested as follows, and the results are shown in Table 2.

[0145] 1) First-cycle discharge specific capacity: At room temperature (35℃), constant current charge-discharge performance was tested using a LAND battery testing system (Wuhan Landian Electronics Co., Ltd.). The charge-discharge rate was 0.1C, and the charge-discharge cutoff voltage relative to the lithium / lithium-ion reference electrode was 3V~4.4V. The first-cycle discharge specific capacity was calculated and recorded as C0 (unit: mAh / g).

[0146] 2) Capacity retention after 1000 cycles: Constant current charge-discharge performance was tested at room temperature (35℃) using a LAND battery testing system (Wuhan Landian Electronics Co., Ltd.). The charge-discharge rate was 1C, and the charge-discharge cutoff voltage relative to the lithium / lithium-ion reference electrode was 3V~4.4V. The discharge capacity of the first cycle was recorded as C1 (unit: mAh), and the discharge capacity of the 1000th cycle was recorded as C... 1000 (Unit: mAh). Capacity retention rate after 1000 cycles = (C 1000 / C1)×100%.

[0147] 3) Battery thermal abuse safety test (250℃ furnace temperature): Place the battery in a heating furnace and heat it to the set temperature (usually 200℃, or adjusted to 250℃ depending on the battery type) at a rate of 5℃ / min; hold the temperature for 2 hours and observe whether the cell experiences thermal runaway. If it does not run away within the set range, continue heating until it runs away at 300℃; record the temperature change, voltage change, and whether there is smoke, fire, or explosion throughout the process. If the battery does not catch fire or explode after holding at 250℃ for 2 hours, and the casing is not cracked, the test result is qualified. If the battery catches fire, explodes, or the casing cracks within 2 hours of holding at 250℃, the test result is unqualified.

[0148] Table 2

[0149]

[0150] Analysis of Table 2 shows that, compared with Comparative Examples 1-5, the batteries in Examples 1-14 have better long-term cycle stability and lower risk of thermal runaway.

[0151] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention 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; and 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 the present invention.

Claims

1. A battery, characterized by, The device includes a battery cell and an encapsulation material present on the surface of the battery cell; from the side closest to the battery cell to the side furthest from the battery cell, the encapsulation material includes a composite ceramic layer, a first polymer layer and a second polymer layer stacked sequentially. The composite ceramic layer comprises a ceramic material and a third polymer; the third polymer comprises one or more of polyolefins, polyacrylates, polyurethanes, and polyimides. The first polymer layer comprises one or more of polyolefins, polyacrylates, and polyurethanes; The second polymer layer includes a second polymer, which includes resin structural units, said resin structural units including one or more of epoxy structural units, polyester structural units, phenolic structural units, vinyl ester structural units, and acrylic structural units.

2. The battery of claim 1, wherein, The mass ratio of the ceramic material to the third polymer is 10:(1-5). And / or, the ceramic material includes one or more of alumina, zirconium oxide, boehmite, lithium lanthanum zirconium oxide, lithium titanium aluminum phosphate, titanium dioxide, silicon carbide, silicon oxide, and silicon nitride; And / or, the particle size D50 of the ceramic material is 0.1μm-3μm.

3. The battery according to claim 1 or 2, characterized in that, The second polymer further includes a curing agent structural unit, which includes an amine structural unit and / or an amide structural unit; preferably, the mass ratio of the resin structural unit to the curing agent structural unit is 10:(1~4).

4. The battery according to any one of claims 1 to 3, characterized in that, The polyolefin includes polyethylene and / or polypropylene; And / or, the polyacrylate includes polymethyl acrylate.

5. The battery according to any one of claims 1 to 4, characterized in that The thickness of the composite ceramic layer is 30μm-100μm, preferably 50μm-80μm; And / or, the thickness of the first polymer layer is 40 μm-100 μm; And / or, the thickness of the second polymer layer is 50μm-100μm.

6. The battery according to any one of claims 1 to 5, wherein The elastic modulus of the composite ceramic layer is 2GPa-6GPa, preferably 3GPa-5GPa; And / or, the pull-out force between the two first polymer layers is 100N / 15mm-200N / 15mm; And / or, the battery is a solid-state battery.

7. A method for preparing a battery according to any one of claims 1-6, characterized in that, Includes the following steps: S1. A first slurry containing ceramic material and a third polymer is coated on the surface of the battery cell to form a composite ceramic layer, thus obtaining a first intermediate battery cell; S2. The first polymer and the first intermediate battery cell are subjected to hot-pressing composite treatment to form a first polymer layer on the side of the composite ceramic layer away from the battery cell; S3. A second raw material containing a second polymer monomer is coated on the side of the first polymer layer away from the composite ceramic layer, and after curing reaction, a second polymer layer is formed, thus obtaining the battery.

8. The preparation method according to claim 7, characterized in that, The curing reaction temperature is 25℃-300℃, and the curing reaction time is 10min-120min.

9. A battery pack, characterized in that, It includes at least two batteries as described in claim 8 that are interconnected.

10. An electrical appliance, characterized in that, It includes the battery of claim 8 or the battery pack of claim 9.

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