Positive electrode plate for capacitor, preparation method therefor, and ultra-thin supercapacitor

Abstract

To provide a positive electrode sheet for a capacitor, a method of manufacturing the same, and an ultrathin supercapacitor.SOLUTION: The positive electrode sheet for a capacitor includes a first active material layer containing a positive electrode active material, a carbon electrode material, a positive electrode conductive agent, and a positive electrode binder. The present invention not only increases the specific energy of the capacitor and ensures the long-endurance capability, but also realizes the miniaturization and ultra-thinning of the terminal product.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention belongs to the field of capacitors, and relates to a positive electrode sheet for capacitors, a manufacturing method thereof, and an ultra-thin supercapacitor. [Background technology]

[0002] Currently, supercapacitors mainly use a wound structure and are relatively large in size. However, compared to small-sized capacitors, the design and technology become more difficult, and the cost also rises significantly. Especially in the ultra-thin application market, the relatively large thickness of the capacitor limits its widespread use. In addition, the specific energy of supercapacitors is low, so if a supercapacitor is designed to be small, its capacity will be relatively low and its self-discharge will be large, which poses a risk to the driving range.

[0003] CN106783223A discloses a wound-type all-solid-state supercapacitor and a manufacturing method thereof, and further discloses that the wound-type all-solid-state supercapacitor includes a lower metal foil, a lower metal foil coating, an upper metal foil, an upper metal foil coating, a winding core, a shell, a conductive silver paste coating, an electrode lead wire, and an adhesive tape, and that the supercapacitor core is composed of the lower metal foil, the lower metal foil coating, the upper metal foil, the upper metal foil coating, the winding core, and the adhesive tape.

[0004] CN101937774A discloses a method for manufacturing a wound-type supercapacitor, which further discloses: (1) selecting a carbon nanotube thin film prepared by a direct growth method as an electrode material; (2) cutting the carbon nanotube film into multiple carbon nanotube film chips; (3) successively laying a long separator flat in a volatile organic solvent; 4) laying multiple carbon nanotube film chips in a head-to-tail connected state on the separator, and completely evaporating the organic solvent on the separator where the carbon nanotube film is laid; and 5) winding and packaging the separator to obtain the wound supercapacitor.

[0005] The thickness of conventional supercapacitors with a winding structure cannot meet the requirements for ultra-thin terminal products, and the problem of range caused by the decrease in specific capacitance remains unignorable. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] China Patent Publication CN106783223A [Patent Document 2] China Patent Publication CN101937774A Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention addresses the shortcomings of the prior art by providing a positive electrode sheet for a capacitor that has high specific energy and low self-discharge, ensures long driving range, and enables miniaturization and ultra-thinness of terminal products, a manufacturing method thereof, and an ultra-thin supercapacitor. [Means for solving the problem]

[0008] To achieve this objective, the present invention employs the following technical solutions. In a first aspect, the present invention provides a positive electrode sheet for a capacitor, comprising a first active material layer including a positive electrode active material, a carbon electrode material, a positive electrode conductive agent, and a positive electrode binder.

[0009] The present invention adds a carbon electrode material to the positive electrode active material to form a monolithic structure, thereby constructing an electric double layer structure of a supercapacitor, which combines the advantages of a supercapacitor and a lithium-ion battery, ensuring good multiplier output capability and effectively increasing the specific energy.

[0010] In a preferred embodiment of the present invention, the carbon electrode material is a porous carbon electrode material. Preferably, the porous carbon electrode material comprises porous activated carbon and / or biomass carbon.

[0011] Preferably, the specific surface area of ​​the porous carbon electrode material is 1400 to 2000 m 2 / g, for example, 1400m 2 / g, 1450m 2 / g, 1500m 2 / g, 1550m 2 / g, 1600m 2 / g, 1650m 2 / g, 1700m 2 / g, 1800m 2 / g, 1900m 2 / g, 1950m 2 / g or 2000m 2 / g, but is not limited to the recited values, and other unrecited values ​​within the range of values ​​also apply.

[0012] Preferably, the median particle size of the carbon electrode material is 3 to 10 μm, and may be, for example, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, or 10 μm, but is not limited to the listed values, and other unlisted values ​​within the range apply as well.

[0013] In the present invention, a porous carbon electrode material with a large specific surface area is added to the positive electrode sheet of the capacitor to form an electric double layer structure, which is advantageous in increasing the energy density of the capacitor.

[0014] In a preferred embodiment of the present invention, the total mass of the first active material layer is 100%, and the mass fraction of the positive electrode active material is 50 to 94%, and may be, for example, 50%, 55%, 56%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 92%, or 94%, but is not limited to the listed values, and other unlisted values ​​within the range also apply.

[0015] The mass fraction of the positive electrode conductive agent is 1 to 10%, and may be, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, but is not limited to the listed values, and other unlisted values ​​within the range also apply.

[0016] The mass fraction of the positive electrode binder is 2 to 10%, and may be, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, but is not limited to the listed values, and other unlisted values ​​within the range also apply.

[0017] The mass fraction of the carbon electrode material is 3 to 50%, and may be, for example, 3%, 5%, 10%, 12%, 15%, 18%, 20%, 25%, 30%, 35%, 36%, 40%, 43%, 45%, 48%, or 50%, but is not limited to the listed values, and other unlisted values ​​within the range also apply.

[0018] In a preferred embodiment of the present invention, the positive electrode active material includes a lithium-containing compound, and the lithium-containing compound includes any one or a combination of at least two of a layered transition metal oxide, a polyanion compound, or a spinel compound.

[0019] Preferably, the layered transition metal oxide comprises LiMO2, where M comprises any one or a combination of at least two of Co, Ni, or Mn.

[0020] Preferably, the polyanionic compound is LiFePO4 and / or (LiMn x Fe 1-x PO4), where x is 0.1 to 0.6, and may be, for example, 0.1, 0.12, 0.15, 0.28, 0.25, 0.3, 0.35, 0.36, 0.4, 0.45, 0.5, 0.55, 0.58, or 0.6, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0021] Preferably, the spinel compound comprises lithium manganate.

[0022] Preferably, the positive electrode conductive agent comprises any one or a combination of at least two of conductive carbon black, carbon nanotubes, graphene, or carbon fiber conductive agents, where typical but non-limiting combinations include a combination of conductive carbon black and carbon nanotubes, a combination of carbon nanotubes and graphene, a combination of graphene and a carbon fiber conductive agent, a combination of conductive carbon black, carbon nanotubes, and graphene, a combination of carbon nanotubes, graphene, and a carbon fiber conductive agent, etc.

[0023] Preferably, the specific surface area of ​​the positive electrode conductive agent is 40 to 100 m 2 / g, for example, 40m 2 / g, 45m 2 / g, 50m 2 / g, 55m 2 / g, 60m 2 / g, 65m 2 / g, 70m 2 / g, 75m 2 / g, 80m 2 / g, 85m 2 / g, 90m 2 / g, 95m 2 / g or 100m 2 / g, but is not limited to the recited values, and other unrecited values ​​within the range of values ​​also apply.

[0024] Preferably, the median particle size of the positive electrode conductive agent is 10 to 100 nm, and may be, for example, 10 nm, 15 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm, but is not limited to the listed numerical values, and other numerical values ​​not listed within the numerical range also apply.

[0025] Preferably, the positive electrode binder includes any one or a combination of at least two of polyvinylidene fluoride, polytetrafluoroethylene, and polyacrylic acid, where typical but non-limiting combinations are a combination of polyvinylidene fluoride and polytetrafluoroethylene, a combination of polytetrafluoroethylene and polyacrylic acid, a combination of polyvinylidene fluoride, polytetrafluoroethylene, and polyacrylic acid, a combination of polyvinylidene fluoride and polyacrylic acid, etc.

[0026] The positive electrode binder of the present invention can ensure the adhesive strength inside the positive electrode material, help improve the structural strength, and ensure the molding effect.

[0027] In a preferred embodiment of the present invention, the positive electrode sheet for a capacitor further includes a positive electrode current collector, and the first active material layer is provided on at least one surface of the positive electrode current collector.

[0028] Preferably, the thickness of the positive electrode current collector is 6 to 20 μm, and may be, for example, 6 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, or 20 μm, but is not limited to the listed numerical values, and other numerical values ​​not listed within the numerical range also apply.

[0029] Preferably, the positive electrode current collector comprises aluminum foil or aluminum mesh.

[0030] In a second aspect, the present invention provides a method for manufacturing a positive electrode sheet for a capacitor according to the first aspect, the method comprising: mixing a positive electrode active material, a carbon electrode material, a positive electrode conductive agent, and a positive electrode binder to obtain a positive electrode material, and processing and shaping the obtained positive electrode material to obtain a first active material layer.

[0031] The present invention is not specifically limited to a processing and forming process for the positive electrode material, and any manufacturing process or combination of processes commonly used in the industry that can process the positive electrode material to form a sheet-shaped active material layer may be adopted. For example, the processing and forming may be any one or a combination of at least two of deposition, hot pressing, coating, and roll pressing. Those skilled in the art may select different processing and forming processes depending on the properties of the positive electrode material.

[0032] In a preferred embodiment of the present invention, the mixing includes dry mixing or wet mixing. Preferably, when the thickness of the positive electrode sheet for a capacitor is greater than 200 μm, the mixing is performed by dry mixing, and when the thickness of the positive electrode sheet for a capacitor is less than or equal to 200 μm, the mixing is performed by wet mixing.

[0033] The present invention employs different mixing methods depending on the thickness of the positive electrode sheet. Preferably, the manufacturing method further includes providing a positive electrode current collector, and combining a positive electrode material with the positive electrode current collector to form the first active material layer on at least one surface of the positive electrode current collector.

[0034] Preferably, the combining includes thermocompressing the positive electrode material onto the surface of a positive electrode current collector, or forming the positive electrode material into a positive electrode slurry and applying it to the surface of a positive electrode current collector, so as to form the first active material layer.

[0035] Preferably, the temperature of the thermocompression bonding is 100 to 200°C, and may be, for example, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, or 200°C, but is not limited to the listed values, and other unlisted values ​​within the range of values ​​also apply.

[0036] Preferably, the positive electrode slurry is prepared by mixing a positive electrode material with a solvent, and the mass ratio of the positive electrode material to the solvent is 0.4 to 0.8, and may be, for example, 0.4, 0.42, 0.45, 0.5, 0.53, 0.55, 0.6, 0.62, 0.65, 0.7, 0.72, 0.75, or 0.8, but is not limited to the listed numerical values, and other numerical values ​​not listed within the numerical range also apply.

[0037] In the present invention, when the positive electrode material is mixed and produced by dry mixing, the compounding method used is thermocompression bonding; when the positive electrode material is mixed and produced by wet mixing, the compounding method used is coating. Those skilled in the art can choose according to actual circumstances. That is, with regard to the method of producing a positive electrode sheet, the present invention provides the following two technical solutions:

[0038] In Method 1, a positive electrode active material, a carbon electrode material, a positive electrode conductive agent, and a positive electrode binder are added to a mixing device in a certain proportion and mixed uniformly to obtain a positive electrode material dry powder. The positive electrode material dry powder is then thermocompressed to form a positive electrode dry sheet of a desired thickness. The positive electrode dry sheet is then attached to the surface of a positive electrode collector to obtain a positive electrode sheet.

[0039] In method 2, the positive electrode binder and the solvent are mixed in the appropriate proportions to obtain a positive electrode paste solution, and then the positive electrode conductive agent is added and mixed uniformly to obtain a conductive paste solution. After that, the positive electrode active material and the carbon electrode material are added to the conductive paste solution and mixed thoroughly to obtain a wet slurry. Finally, the wet slurry is applied to the surface of the positive electrode collector and calcined to obtain a positive electrode sheet.

[0040] In a third aspect, the present invention provides an ultra-thin supercapacitor comprising a housing and an upper cover body, the housing and the upper cover body forming an accommodating chamber, a positive electrode sheet, a separator, and a negative electrode sheet stacked in this order in the accommodating chamber, the positive electrode sheet being connected to the housing, and the negative electrode sheet being at least partially connected to the upper cover body, the positive electrode sheet being the positive electrode sheet for a capacitor according to the first aspect, or the positive electrode sheet being manufactured by the manufacturing method according to the second aspect.

[0041] The positive electrode sheet, separator and negative electrode sheet in the ultra-thin supercapacitor provided by the present invention all adopt a single-layer structure. Compared with the conventional multi-layer laminated sheet or wound format, the present invention effectively increases the energy density of the ultra-thin supercapacitor, reduces the self-discharge of the capacitor and ensures long-lasting operation. It also has high reliability and safety, is easy to remove, is favorable for mass production, and achieves miniaturization and ultra-thinness, making it suitable for ultra-thin terminal products.

[0042] In a preferred embodiment of the present invention, the positive electrode sheet further includes a positive electrode current collector provided between the housing and the first active material layer.

[0043] Preferably, the housing is also filled with an electrolyte.

[0044] Preferably, the housing is connected to the top cover by an insulating assembly.

[0045] Preferably, the insulating assembly is an insulating rubber ring.

[0046] In a preferred embodiment of the present invention, the negative electrode sheet includes a second active material layer containing a negative electrode active material, a negative electrode conductive agent, and a negative electrode binder.

[0047] Preferably, the negative electrode sheet further includes a negative electrode current collector provided between the upper cover and the second active material layer.

[0048] Preferably, the negative electrode current collector includes any one of copper foil, nickel mesh, aluminum foil, and aluminum mesh.

[0049] Preferably, the thickness of the negative electrode current collector is 6 to 20 μm, and may be, for example, 6 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, or 20 μm, but is not limited to the listed numerical values, and other numerical values ​​not listed within the numerical range also apply.

[0050] Preferably, the total mass of the second active material is 100%, and the mass fraction of the negative electrode active material is 80 to 96%, for example, 80%, 82%, 84%, 85%, 88%, 90%, 92%, 94%, 95%, or 96%, but is not limited to the listed values, and other unlisted values ​​within the range also apply.

[0051] The mass fraction of the negative electrode conductive agent is 2 to 10%, and may be, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, but is not limited to the listed values, and other unlisted values ​​within the range also apply.

[0052] The mass fraction of the negative electrode binder is 2 to 10%, and may be, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, but is not limited to the listed values, and other unlisted values ​​within the range also apply.

[0053] Preferably, the negative electrode active material comprises lithium titanate and / or a carbon active material, more preferably lithium titanate.

[0054] The negative electrode material of the present invention preferably uses lithium titanate as the negative electrode active material, which can significantly improve the multiplication performance and cycle life of the ultra-thin supercapacitor, and at the same time, due to its high voltage platform, there is no risk of over-discharge and lithium deposition, which greatly improves safety.

[0055] Preferably, the carbon active material comprises any one or a combination of at least two of graphite, soft carbon, hard carbon, or mesophase carbon microspheres, where typical but non-limiting combinations are graphite and soft carbon, hard carbon and mesophase carbon microspheres, graphite and hard carbon, graphite, hard carbon and mesophase carbon microspheres, etc.

[0056] Preferably, the negative electrode conductive agent comprises any one or a combination of at least two of conductive carbon black, carbon nanotubes, graphene, or carbon fiber conductive agents, where typical but non-limiting combinations include a combination of conductive carbon black and carbon nanotubes, a combination of carbon nanotubes and graphene, a combination of graphene and a carbon fiber conductive agent, a combination of carbon nanotubes, graphene and a carbon fiber conductive agent, a combination of conductive carbon black, carbon nanotubes and graphene, etc.

[0057] The negative electrode binder includes one or a combination of at least two of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylic acid, sodium carboxymethyl cellulose, and styrene-butadiene rubber. The negative electrode adhesive of the present invention can ensure the adhesive strength within the positive electrode material, improve the structural strength, and ensure the molding effect.

[0058] For example, the present invention provides the following two technical solutions for the manufacturing method of the negative electrode sheet.

[0059] In Method 1, the negative electrode active material, the negative electrode conductive agent, and the negative electrode adhesive are added to a mixing device in a certain proportion and mixed uniformly to obtain a negative electrode material dry powder, and then the negative electrode material dry powder is thermocompressed to form a negative electrode dry sheet of a desired thickness, and then the negative electrode dry sheet is attached to the surface of a negative electrode current collector to obtain a negative electrode sheet.

[0060] In method 2, the negative electrode adhesive and the solvent are mixed in the appropriate ratio to obtain a negative electrode paste solution, and then the negative electrode conductive agent is added and mixed uniformly to obtain a conductive paste solution. After that, the negative electrode active material is added to the conductive paste solution and mixed thoroughly to obtain a wet slurry. Finally, the wet slurry is applied to the surface of the negative electrode current collector and calcined to obtain a negative electrode sheet.

[0061] In a preferred embodiment of the present invention, the separator includes a polymer separator, a nonwoven fabric separator, or a glass fiber separator.

[0062] Preferably, the housing is made of stainless steel.

[0063] Preferably, the upper cover is made of stainless steel.

[0064] The present invention employs a housing and a top cover made of stainless steel, which can meet the requirements of high temperature and high humidity environments, thereby improving the reliability and environmental adaptability of the product.

[0065] Preferably, the material of the insulating assembly includes any one of polypropylene, polyphenylene sulfide, and polyether ether ketone.

[0066] The insulating assembly of the present invention can withstand high temperatures and meet peak welding requirements, which is advantageous for fully automated assembly of supercapacitors.

[0067] Preferably, the electrolyte solution contains an organic solvent and a lithium salt.

[0068] Preferably, the organic solvent comprises a carbonate-based solvent and / or an ether-based solvent.

[0069] The carbonate-based solvent and the ether-based solvent in the present invention may be any solvent that can be used as an electrolyte component and is well known to those skilled in the art, and are not limited thereto.

[0070] Preferably, the lithium salt comprises any one or a combination of at least two of LiPF, LiTFSI, LiFSI, LiBOB, or LiBF, where exemplary but non-limiting combinations are LiPF and LiTFSI, LiTFSI, LiFSI and LiBOB, LiTFSI, LiFSI, LiBOB and LiBF, LiTFSI and LiBF, LiPF, LiTFSI and LiFSI, and the like.

[0071] The numerical ranges set forth in the present invention include not only the numerical values ​​listed above, but also any numerical values ​​between the numerical ranges not shown, and due to character limitations, the present invention does not exhaustively list specific numerical values ​​included in the above ranges.

[0072] The beneficial effects of the present invention compared to the prior art are: (1) By adding a carbon electrode material into the positive electrode active material, the present invention establishes an electric double layer structure of the supercapacitor, which combines the advantages of the supercapacitor and the lithium-ion battery, shortens the transmission distance, helps to reduce the thickness of the capacitor, ensures good multiplier output capability, and effectively improves the specific energy. (2) The positive electrode sheet, separator, and negative electrode sheet in the ultra-thin supercapacitor provided by the present invention all adopt a single-layer structure, which effectively increases the energy density of the ultra-thin supercapacitor, reduces the self-discharge of the capacitor, and ensures long-lasting operation. At the same time, it has high reliability and safety, and achieves miniaturization and ultra-thinness, making it suitable for ultra-thin terminal products. (3) The manufacturing process of the present invention is simple, has high productivity, and is advantageous for mass production. [Brief explanation of the drawings]

[0073] [Figure 1] 1 is a structural schematic diagram of an ultra-thin supercapacitor provided by Example 1 of the present invention; FIG. [Figure 2] 1 is a structural schematic diagram of an ultra-thin supercapacitor provided by Example 10 of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0074] In describing the present invention, the orientations or positional relationships indicated by the terms "center," "upper," "lower," "top," "bottom," "inner," and "outer" are based on the orientations or positional relationships shown in the drawings, and are merely for the purpose of easily and simply describing the present invention and do not indicate or imply that a device or element must have a particular orientation or be configured and operated in a particular orientation, and therefore should not be understood as a limitation on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or the number of the indicated technical features. Thus, a feature qualified as "first," "second," etc., explicitly or implicitly indicates that one or more of the feature is included.

[0075] The technical solution of the present invention will be further described below through specific embodiments in combination with the drawings. In one specific embodiment, the present invention provides a positive electrode sheet for a capacitor, comprising a first active material layer including a positive electrode active material, a carbon electrode material, a positive electrode conductive agent, and a positive electrode binder. By adding the carbon electrode material to the positive electrode active material, the present invention establishes an electric double layer structure of a supercapacitor, combining the advantages of a supercapacitor and a lithium-ion battery, ensuring good multiplier output capability and effectively increasing specific energy.

[0076] In some embodiments, the carbon electrode material is a porous carbon electrode material. Specifically, the porous carbon electrode material comprises porous activated carbon and / or biomass carbon. The specific surface area of ​​the porous carbon electrode material is 1400 to 2000 m. 2 / g, and the median particle size of the carbon electrode material is 3 to 10 μm. The present invention is advantageous in that an electric double layer structure is formed by adding a porous carbon electrode material with a high specific surface area to a positive electrode sheet of a capacitor, thereby increasing the energy density of the capacitor.

[0077] In some embodiments, the total mass of the first active material layer is 100%, and the mass fraction of the positive electrode active material is 50 to 94%, the mass fraction of the positive electrode conductive agent is 1 to 10%, the mass fraction of the positive electrode binder is 2 to 10%, and the mass fraction of the carbon electrode material is 3 to 50%.

[0078] In some embodiments, the positive electrode active material includes a lithium-containing compound including any one or a combination of at least two of a layered transition metal oxide, a polyanion compound, or a spinel compound. Specifically, the layered transition metal oxide includes LiMO2, where M includes any one or a combination of at least two of Co, Ni, or Mn. The polyanion compound is LiFePO4 and / or (LiMn x Fe 1-x PO4), where x is 0.1 to 0.6. The spinel compound contains lithium manganate.

[0079] In some embodiments, the positive electrode conductive agent comprises one or a combination of at least two of conductive carbon black, carbon nanotubes, graphene, or carbon fiber conductive agents. Specifically, the positive electrode conductive agent has a specific surface area of ​​40 to 100 m. 2 / g, and the median particle size of the positive electrode conductive agent is 10 to 100 nm.

[0080] In some embodiments, the positive electrode binder includes any one or a combination of at least two of polyvinylidene fluoride, polytetrafluoroethylene, and polyacrylic acid, which ensures adhesion within the positive electrode material, helps improve structural strength, and ensures molding effects.

[0081] In some embodiments, the positive electrode sheet for a capacitor further includes a positive electrode current collector, and the first active material layer is disposed on at least one surface of the positive electrode current collector, thereby improving the conductivity of the positive electrode sheet.

[0082] Specifically, the positive electrode current collector has a thickness of 6 to 20 μm.The positive electrode current collector includes an aluminum foil or an aluminum mesh.

[0083] In another specific embodiment, the present invention provides a method for manufacturing a positive electrode sheet for a capacitor, the method including mixing a positive electrode active material, a carbon electrode material, a positive electrode conductive agent, and a positive electrode binder to obtain a positive electrode material, and processing and shaping the positive electrode material to obtain a first active material layer.

[0084] In some embodiments, the mixing includes dry mixing or wet mixing. Specifically, when the thickness of the capacitor positive electrode sheet is greater than 200 μm, the mixing is performed by dry mixing, and when the thickness of the capacitor positive electrode sheet is less than or equal to 200 μm, the mixing is performed by wet mixing. That is, the present invention employs different mixing methods depending on the thickness of the positive electrode sheet.

[0085] In some embodiments, the forming process can employ any one or a combination of at least two of deposition, hot pressing, coating, or roll pressing.

[0086] In some embodiments, the method further includes providing a positive electrode current collector and combining the positive electrode material with the positive electrode current collector to form a first active material layer on at least one surface of the positive electrode charge body.

[0087] In some embodiments, the combining includes thermocompressing the positive electrode material onto a surface of a positive electrode current collector, or forming the positive electrode material into a positive electrode slurry and applying it to a surface of a positive electrode current collector to form the first active material layer.

[0088] In the present invention, when the positive electrode material is prepared by dry mixing, the compounding method used is thermocompression bonding, and when the positive electrode material is prepared by wet mixing, the compounding method used is coating, which can be selected by those skilled in the art according to the actual situation.

[0089] For example, the present invention provides the following two technical solutions for the manufacturing method of a positive electrode sheet for a capacitor.

[0090] As Scheme 1, the manufacturing method of the capacitor positive electrode sheet specifically includes the following steps: (1) Mechanical mixing: Add the positive electrode active material, carbon electrode material, positive electrode conductive agent and positive electrode binder into a mixing device in the appropriate proportions, and stir thoroughly to obtain a dry powder of the positive electrode material, where the stirring revolution range is 5-25 rpm and the stirring rotation range is 500-2500 rpm; (2) Sheet formation by thermocompression: The cathode material dry powder obtained in step (1) is formed into a cathode dry sheet of a required thickness by thermocompression, and the thermocompression temperature is 100 to 200°C; (3) Composition: The cathode dry sheet obtained in step (2) is adhered to the surface of the cathode current collector to obtain a cathode sheet; (4) Sheet punching: Using punching equipment, punch the positive electrode sheet from step (3) to the required diameter.

[0091] As Scheme 2, the manufacturing method of the capacitor positive electrode sheet specifically includes the following steps: S1. Dissolving the positive electrode binder: Add the positive electrode binder and the solvent into the stirring cylinder in a certain proportion and stir thoroughly to obtain a positive electrode paste solution, the solvent including N-methylpyrrolidone or deionized water, the mass ratio of the positive electrode dry matter to the solvent is 0.4-0.8, the stirring revolution range is 5-25 rpm, and the stirring rotation range is 500-2500 rpm; S2. Mixing the positive electrode conductive agent: Add the positive electrode conductive agent to the positive electrode paste solution of step S1 and stir thoroughly to obtain a conductive paste solution, where the stirring revolution range is 5-25 rpm and the stirring rotation range is 500-2500 rpm; S3. Mixing the positive electrode active material and the carbon electrode material: Add the positive electrode active material and the carbon electrode material to the conductive paste liquid of step S2 and stir thoroughly to obtain a wet slurry, with the stirring revolution range of 5 to 25 rpm and the stirring rotation range of 500 to 2500 rpm; S4. Coating: The wet slurry prepared in step S3 is coated on the surface of the positive electrode current collector using a coating device, and then the coated surface is baked to obtain a positive electrode sheet. S5. Cold pressing: The positive electrode sheet obtained in step S4 is pressed to the required thickness using a cold press device. S6. Sheet punching: The positive electrode sheet from step S5 is punched to the required diameter using punching equipment.

[0092] In another specific embodiment, the present invention provides an ultra-thin supercapacitor comprising an insulated and connected housing and a top cover, the housing and the top cover forming a receiving chamber, a positive electrode sheet, a separator, and a negative electrode sheet stacked in this order within the receiving chamber, the positive electrode sheet being connected to the housing and the negative electrode sheet being at least partially connected to the top cover, the positive electrode sheet being the capacitor positive electrode sheet described in one embodiment or the capacitor positive electrode sheet manufactured by the manufacturing method described in another embodiment. The positive electrode sheet, separator, and negative electrode sheet all have a single-layer structure, which, compared with conventional multi-layer laminated sheets or rolled structures, effectively increases the energy density of the ultra-thin supercapacitor, reduces self-discharge of the capacitor, and ensures long-life operation. Furthermore, the ultra-thin supercapacitor has high reliability and safety, is easy to remove, is favorable for mass production, and achieves miniaturization and ultra-thinness, making it suitable for ultra-thin terminal products.

[0093] The dimensional specifications of the ultra-thin supercapacitor in the present invention include, but are not limited to, 1016 (diameter 10 mm, thickness 1.6 mm), 1216 (diameter 12 mm, thickness 1.6 mm), 2016 (diameter 20 mm, thickness 1.6 mm), 2032 (diameter 20 mm, thickness 3.2 mm), and 2450 (diameter 24 mm, thickness 5 mm).

[0094] In some embodiments, the positive electrode sheet further includes a positive electrode current collector disposed between the housing and the first active material layer.

[0095] In some embodiments, the housing is also filled with an electrolyte. The electrolyte includes an organic solvent and a lithium salt. Specifically, the organic solvent includes a carbonate-based solvent and / or an ether-based solvent. The lithium salt includes any one or a combination of at least two of LiPF6, LiTFSI, LiFSI, LiBOB, and LiBF4.

[0096] In some embodiments, the housing is connected to the top cover by an insulating assembly, which is an insulating rubber ring. Specifically, the insulating assembly is made of one of polypropylene, polyphenylene sulfide, and polyether ether ketone. The insulating assembly can withstand high temperatures and meet peak welding requirements, which is advantageous for fully automated assembly of supercapacitors.

[0097] In some embodiments, the separator includes a polymer separator, a nonwoven fabric separator, or a glass fiber separator. Preferably, the separator is a polymer separator, and specifically, the polymer separator includes a PP (polypropylene, polyethylene) single-layer separator, a PE (polyethylene) single-layer separator, a PP / PE / PP three-layer separator, a PP-coated separator, or a PE-coated separator, which are well known to those skilled in the art.

[0098] In some embodiments, the housing is made of stainless steel. The top cover is made of stainless steel. The present invention uses a housing and a top cover made of stainless steel to meet the requirements of high temperature and high humidity environments, thereby improving the reliability and environmental adaptability of the product.

[0099] In some embodiments, the negative electrode sheet includes a second active material layer including a negative electrode active material, a negative electrode conductive agent, and a negative electrode binder.

[0100] In some embodiments, the negative electrode sheet further includes a negative electrode current collector disposed between the upper cover and the second active material layer.

[0101] Specifically, the negative electrode current collector includes any one of copper foil, nickel mesh, aluminum foil, and aluminum mesh, and has a thickness of 6 to 20 μm.

[0102] Specifically, the total mass of the second active material layer is taken as 100%, and the mass fraction of the negative electrode conductive agent is 2 to 10%, and the mass fraction of the negative electrode binder is 2 to 10%.

[0103] In some embodiments, the negative electrode active material is lithium titanate and / or carbon active material, preferably lithium titanate, which can significantly improve the multiplier performance and cycle life of ultra-thin supercapacitors. At the same time, the high voltage platform eliminates the risk of over-discharge or lithium deposition, significantly improving safety. The carbon active material includes any one or a combination of at least two of graphite, soft carbon, hard carbon, or mesophase carbon microspheres. The negative electrode conductive agent includes any one or a combination of at least two of conductive carbon black, carbon nanotubes, graphene, or carbon fiber conductive agents. The negative electrode binder includes any one or a combination of at least two of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylic acid, sodium carboxymethyl cellulose, or styrene butadiene rubber, which ensures adhesion within the positive electrode material, helps improve structural strength, and ensures molding effectiveness.

[0104] Illustratively, the present invention provides a method for manufacturing a negative electrode sheet, the method for manufacturing a negative electrode sheet including: providing a negative electrode current collector; mixing a negative electrode active material, a negative electrode conductive agent, and a negative electrode binder to obtain a negative electrode material; and combining the negative electrode material with the negative electrode current collector to form a second active material layer on a surface of the negative electrode current collector.

[0105] Specifically, the mixing may be dry mixing or wet mixing. Furthermore, when the thickness of the negative electrode sheet is greater than 200 μm, the mixing is dry mixing, and when the thickness of the negative electrode sheet is less than or equal to 200 μm, the mixing is wet mixing. That is, the present invention employs different mixing methods depending on the thickness of the negative electrode sheet.

[0106] The combining step includes thermocompressing the negative electrode material onto the surface of the negative electrode current collector to form the second active material layer, or forming the negative electrode material into a negative electrode slurry and applying it to the surface of the negative electrode current collector.

[0107] Specifically, in the present invention, when the negative electrode material is mixed and prepared by dry mixing, the compounding method used is thermocompression bonding, and when the negative electrode material is mixed and prepared by wet mixing, the compounding method used is coating. Those skilled in the art can select either method according to the actual situation.

[0108] For example, the present invention provides the following two technical solutions for the manufacturing method of the negative electrode sheet. As Scheme 1, the manufacturing method of the negative electrode sheet specifically includes the following steps: G1. Mechanical mixing: Add the negative electrode active material, negative electrode conductive agent and negative electrode binder into the mixing equipment in the appropriate proportions, and stir thoroughly to obtain a dry powder of negative electrode material, where the stirring revolution range is 5-25 rpm and the stirring rotation range is 500-2500 rpm; G2. Sheet formation by thermocompression: The negative electrode material dry powder obtained in step G1 is thermocompressed to form a negative electrode dry material sheet of a required thickness, and the thermocompression temperature is 100 to 200 ° C.; G3. Adhesion of negative electrode current collector: The negative electrode dry sheet obtained in step G2 is adhered to the surface of the negative electrode current collector to obtain a negative electrode sheet; G4. Sheet punching: Using punching equipment, punch the negative electrode sheet from step G3 to the required diameter. As Scheme 2, the manufacturing method of the negative electrode sheet specifically includes the following steps: S11. Dissolving the negative electrode binder: Add the negative electrode binder and the solvent into the stirring cylinder in a certain proportion and stir thoroughly to obtain a negative electrode paste solution, the solvent including N-methylpyrrolidone or deionized water, the mass ratio of the negative electrode dry matter to the solvent is 0.4-0.8, the stirring revolution range is 5-25 rpm, and the stirring rotation range is 500-2500 rpm; S12. Mixing the negative electrode conductive agent: Add the negative electrode conductive agent to the negative electrode paste solution of step S11 and stir thoroughly to obtain a conductive paste solution, the stirring revolution range is 5 to 25 rpm, and the stirring rotation range is 500 to 2500 rpm; S13. Mixing of negative electrode active material: Add the negative electrode active material to the conductive paste liquid of step S12 and stir thoroughly to obtain a wet slurry, the stirring revolution range is 5 to 25 rpm, and the stirring rotation range is 500 to 2500 rpm; S14. Coating: The wet slurry prepared in step S13 is coated on the surface of the negative electrode current collector using a coating device, and then baked to obtain a negative electrode sheet. S15. Cold pressing: The negative electrode sheet obtained in step S14 is pressed to a required thickness using a cold pressing device. S16. Sheet punching: The negative electrode sheet from step S15 is punched to the required diameter using punching equipment.

[0109] The present invention will be described in more detail below. However, the following examples are merely simple examples of the present invention and do not represent or limit the scope of protection of the present invention, which is governed by the claims.

[0110] Example 1 This embodiment provides an ultra-thin supercapacitor, model number 2016, with a diameter of 20 mm and a thickness of 1.6 mm. As shown in Figure 1, the supercapacitor includes a stainless steel housing 6 and an upper cover 5. The housing 6 is insulated from and connected to the upper cover 5 via an insulating rubber ring 4, forming a receiving chamber. Within the receiving chamber, a positive electrode sheet, a separator 3, and a negative electrode sheet are stacked in this order from the bottom of the housing 6 toward the upper cover 5. The positive electrode sheet is connected to the housing 6, and the negative electrode sheet is connected to the upper cover 5. The positive electrode sheet includes a positive electrode current collector 7 having a diameter of 15.8 mm and a first active material layer 1 provided on the positive electrode current collector 7, and the positive electrode current collector 7 is connected to the housing 6. The positive electrode current collector 7 is made of aluminum foil having a thickness of 180 μm, and the first active material layer 1 is made of lithium cobalt oxide with a specific surface area of ​​1600 m. 2 / g of activated carbon, SP, CNT, and polytetrafluoroethylene. The negative electrode sheet includes a negative electrode current collector 8 having a diameter of 15.8 mm and a second active material layer 2 provided on the negative electrode current collector 8, and the negative electrode current collector 8 is connected to an upper cover 5. The negative electrode current collector 8 is made of aluminum foil having a thickness of 180 μm, and the second active material layer 2 includes lithium titanate, SP, CNT, and polytetrafluoroethylene. The separator 3 is a glass fiber separator 3, and the housing 6 is further filled with an electrolyte, which includes LiPF6, EC, DMC, and EMC.

[0111] In addition, this embodiment provides a method for manufacturing the above-mentioned ultra-thin supercapacitor, which specifically includes the following steps:

[0112] Step 1: Manufacturing a positive electrode sheet, which specifically includes the following substeps: (1) Lithium cobalt oxide, specific surface area 1600m 2 / g of activated carbon, SP, CNT and polytetrafluoroethylene were thoroughly mixed in a mass ratio of 71:20:4:1:4 to obtain a dry powder of a positive electrode material, where the mixing was performed by stirring, with the revolution speed of the stirring mixer being 15 rpm and the rotation speed being 2000 rpm. (2) The cathode material dry powder obtained in step (1) is formed into a 10 μm cathode dry sheet by thermocompression, and the thermocompression temperature is 250° C.; (3) The cathode dry sheet obtained in step (2) is adhered to the surface of the cathode current collector 7 to obtain a cathode sheet, (4) The positive electrode sheet from step (3) is punched to the required diameter using punching equipment.

[0113] Step 2: Manufacturing a negative electrode sheet, which specifically includes the following substeps: S1: Lithium titanate, SP, CNT, and polytetrafluoroethylene were thoroughly mixed in a mass ratio of 91:4:1:4 to obtain a dry powder of a negative electrode material. S2: The negative electrode material dry powder obtained in step S1 is thermocompressed to form a 10 μm negative electrode dry sheet. S3: The negative electrode dry sheet obtained in step S2 is adhered to the surface of the negative electrode current collector 8 to obtain a negative electrode sheet. S4: The negative electrode sheet from step S3 is punched out to the required diameter using punching equipment. Step 3: Assemble the positive electrode sheet, separator 3 and negative electrode sheet by stacking them, and place them into a housing 6, then inject an electrolyte into the housing 6 and package it to obtain an ultra-thin supercapacitor.

[0114] Example 2 This embodiment provides an ultra-thin supercapacitor, which is different from Example 1 in that in the manufacturing process of the positive electrode sheet, the positive electrode active material is lithium nickel cobalt manganese oxide, and the other structure, manufacturing method, materials and proportions are all the same as Example 1.

[0115] Example 3 This example provides an ultra-thin supercapacitor, which is different from Example 1 in that the first active material layer 1 is made of lithium manganese oxide and has a specific surface area of ​​1800 m 2 / g of activated carbon, carbon nanotubes, graphene, and polyvinylidene fluoride, and the second active material layer 2 contains lithium titanate, SP, CNT, and polyvinylidene fluoride, and other structures and sizes are the same as in Example 1. The method for manufacturing the ultra-thin supercapacitor in this example specifically includes the following steps:

[0116] Step 1: Manufacturing a positive electrode sheet, which specifically includes the following substeps: (1) Lithium manganese oxide, specific surface area 1800m 2 / g of activated carbon, carbon nanotubes, graphene, and polyvinylidene fluoride were thoroughly mixed in a mass ratio of 65:22:4:4:5 to obtain a dry powder of a positive electrode material, and the mixing was performed by stirring, with the revolution speed of the stirring mixer being 20 rpm and the rotation speed being 800 rpm. (2) The cathode material dry powder obtained in step (1) is formed into a cathode dry sheet of 15 μm by thermocompression, and the thermocompression temperature is 100° C.; (3) The cathode dry sheet obtained in step (2) is adhered to the surface of a cathode current collector to obtain a cathode sheet; (4) The positive electrode sheet from step (3) is punched to the required diameter using punching equipment.

[0117] Step 2: Manufacturing a negative electrode sheet, which specifically includes the following substeps: S1: Lithium titanate, SP, CNT, and polyvinylidene fluoride were thoroughly mixed in a mass ratio of 85:5:4:6 to obtain a dry powder of a negative electrode material. The mixing was performed by stirring, with the revolution speed of the stirring mixture being 20 rpm and the rotation speed being 800 rpm. S2: The negative electrode material dry powder obtained in step S1 is formed into a negative electrode dry sheet of 15 μm by thermocompression, and the thermocompression temperature is 100 ° C. S3: The negative electrode dry sheet obtained in step S2 is adhered to the surface of the negative electrode current collector to obtain a negative electrode sheet. S4: The negative electrode sheet from step S3 is punched out to the required diameter using punching equipment.

[0118] Step 3: Assemble the positive electrode sheet, separator, and negative electrode sheet by stacking them, place them in the housing 6, and then inject an electrolyte into the housing 6 and package it to obtain an ultra-thin supercapacitor.

[0119] Example 4 This example provides an ultra-thin supercapacitor, which is different from Example 1 in that the first active material layer 1 is made of LiFePO4 and has a specific surface area of ​​1400 m 2 / g biomass carbon, carbon nanotubes, carbon fiber conductive agent, and polytetrafluoroethylene, and the second active material layer 2 contains lithium titanate, SP, carbon fiber conductive agent, and polyvinylidene fluoride, and other structures and sizes are the same as in Example 1. The manufacturing method of the ultra-thin supercapacitor in this example specifically includes the following steps:

[0120] Step 1: Manufacturing a positive electrode sheet, which specifically includes the following substeps: (1)LiFePO4, specific surface area 1400m 2 / g of biomass carbon, carbon nanotubes, carbon fiber conductive agent, and polytetrafluoroethylene were thoroughly mixed in a mass ratio of 55:30:5:4:6 to obtain a dry powder of a positive electrode material, wherein the mixing was performed by stirring, with the revolution speed of the stirring mixer being 5 rpm and the rotation speed being 1500 rpm; (2) The cathode material dry powder obtained in step (1) is formed into a 6 μm cathode dry sheet by thermocompression, and the thermocompression temperature is 120° C.; (3) The cathode dry sheet obtained in step (2) is adhered to the surface of a cathode current collector to obtain a cathode sheet; (4) The positive electrode sheet from step (3) is punched to the required diameter using punching equipment.

[0121] Step 2: Manufacturing a negative electrode sheet, which specifically includes the following substeps: S1: Lithium titanate, SP, carbon fiber conductive agent, and polyvinylidene fluoride are thoroughly mixed in a mass ratio of 90:3:5:2 to obtain a dry powder of a negative electrode material, and the mixing is performed by stirring, with the revolution speed of the stirring and mixing being 5 rpm and then rotating to 1500 rpm. S2: The negative electrode material dry powder obtained in step S1 is formed into a 6 μm negative electrode dry sheet by thermocompression, and the thermocompression temperature is 120 ° C. S3: The negative electrode dry sheet obtained in step S2 is adhered to the surface of the negative electrode current collector to obtain a negative electrode sheet. S4: The negative electrode sheet from step S3 is punched out to the required diameter using punching equipment.

[0122] Step 3: Assemble the positive electrode sheet, separator, and negative electrode sheet by stacking them, place them in the housing 6, and then inject an electrolyte into the housing 6 and package it to obtain an ultra-thin supercapacitor.

[0123] Example 5 This example provides an ultra-thin supercapacitor, and is different from Example 1 in that the first active material layer 1 is made of LiMn 0.5 Fe 0.5 PO4, specific surface area 2000m 2 / g biomass carbon, conductive carbon black, carbon fiber conductive agent, and polyacrylic acid, and the second active material layer 2 contains lithium titanate, graphene, carbon fiber conductive agent, and polyacrylic acid, and other structures and sizes are the same as in Example 1. The manufacturing method of the ultra-thin supercapacitor in this example specifically includes the following steps.

[0124] Step 1: Manufacturing a positive electrode sheet, which specifically includes the following substeps: (1) LiMn 0.5 Fe0.5 PO4 , specific surface area 2000m 2 / g of biomass carbon, conductive carbon black, carbon fiber conductive agent, and polyacrylic acid were thoroughly mixed in a mass ratio of 90:5:2:2:2 to obtain a dry powder of a positive electrode material, and the mixing was performed by stirring, with the revolution speed of the stirring mixer being 25 rpm and the rotation speed being 2500 rpm; (2) The cathode material dry powder obtained in step (1) is formed into a 20 μm cathode dry sheet by thermocompression, and the thermocompression temperature is 200° C.; (3) The cathode dry sheet obtained in step (2) is adhered to the surface of a cathode current collector to obtain a cathode sheet; (4) The positive electrode sheet from step (3) is punched to the required diameter using punching equipment.

[0125] Step 2: Manufacturing a negative electrode sheet, which specifically includes the following substeps: S1: Lithium titanate, graphene, carbon fiber conductive agent, and polyacrylic acid were thoroughly mixed in a mass ratio of 88:4:4:4:4 to obtain a dry powder of anode material. The mixture was stirred at a revolution speed of 25 rpm and a rotation speed of 2500 rpm. S2: The negative electrode material dry powder obtained in step S1 is formed into a negative electrode dry sheet of 20 μm by thermocompression, and the thermocompression temperature is 200 ° C. S3: The negative electrode dry sheet obtained in step S2 is adhered to the surface of the negative electrode current collector to obtain a negative electrode sheet. S4: The negative electrode sheet from step S3 is punched out to the required diameter using punching equipment.

[0126] Step 3: Assemble the positive electrode sheet, separator, and negative electrode sheet by stacking them, place them in the housing 6, and then inject an electrolyte into the housing 6 and package it to obtain an ultra-thin supercapacitor.

[0127] Example 6 This example provides an ultra-thin supercapacitor, and is different from Example 1 in that the first active material layer 1 is LiMn 0.3 Fe 0.7 PO4, specific surface area 1500m 2 / g of activated carbon, conductive carbon black, graphene, and polytetrafluoroethylene, and the second active material layer 2 includes mesophase carbon microspheres, graphene, carbon nanotubes, and polytetrafluoroethylene, and other structures and sizes are the same as in Example 1. The manufacturing method of the ultra-thin supercapacitor in this example specifically includes the following steps:

[0128] Step 1: Manufacturing a positive electrode plate, which specifically includes the following substeps: (1) LiMn 0.3 Fe 0.7 PO4, specific surface area 1500m 2 / g of activated carbon, conductive carbon black, graphene, and polytetrafluoroethylene were thoroughly mixed in a mass ratio of 75:15:5:3:2 to obtain a dry powder of a positive electrode material, and the mixing was performed by stirring, with the revolution speed of the stirring mixer being 22 rpm and the rotation speed being 2000 rpm. (2) The cathode material dry powder obtained in step (1) is formed into a 12 μm cathode dry sheet by thermocompression, and the thermocompression temperature is 180° C.; (3) The cathode dry sheet obtained in step (2) is adhered to the surface of a cathode current collector to obtain a cathode sheet; (4) The positive electrode sheet from step (3) is punched to the required diameter using punching equipment.

[0129] Step 2: Manufacturing a negative electrode plate, which specifically includes the following substeps: S1: Mesophase carbon microspheres, graphene, carbon nanotubes, and polytetrafluoroethylene were thoroughly mixed in a mass ratio of 92:2:3:3 to obtain a dry powder of anode material. The mixing was performed by stirring, with the revolution speed of the stirring mixer being 22 rpm and the rotation speed being 2000 rpm. S2: The negative electrode material dry powder obtained in step S1 is formed into a 12 μm negative electrode dry sheet by thermocompression, and the thermocompression temperature is 180 ° C. S3: The negative electrode dry sheet obtained in step S2 is adhered to the surface of the negative electrode current collector to obtain a negative electrode sheet. S4: The negative electrode sheet from step S3 is punched out to the required diameter using punching equipment. Step 3: Assemble the positive electrode sheet, separator, and negative electrode sheet by stacking them, place them in the housing 6, and then inject an electrolyte into the housing 6 and package it to obtain an ultra-thin supercapacitor.

[0130] Example 7 This example provides an ultra-thin supercapacitor, which is different from Example 1 in that the thickness of the positive electrode collector and the negative electrode collector are both 220 μm, and the positive electrode sheet and the negative electrode sheet are respectively manufactured by wet mixing. The other manufacturing materials and their proportions are all the same as those in Example 1, and the manufacturing method specifically includes the following steps:

[0131] Step 1: Manufacturing a positive electrode sheet, which specifically includes the following substeps: (1) Polytetrafluoroethylene and N-methylpyrrolidone are thoroughly mixed in a mass ratio of 0.5 to obtain a positive electrode paste solution, and the mixing is performed by stirring, with the revolution speed of the stirring mixture being 15 rpm and the rotation speed being 2000 rpm; (2) Add SP and CNT to the positive electrode paste solution and mix evenly to obtain a positive electrode conductive paste solution. The mixing is performed by stirring, with the revolution speed of 15 rpm and the rotation speed of 2000 rpm. (3) Lithium cobalt oxide with a specific surface area of ​​1600 m 2 / g of activated carbon was added to the positive electrode conductive paste liquid and mixed uniformly, and the revolution speed of the stirring and mixing was 15 rpm and the rotation speed was 2000 rpm. (4) The wet slurry is applied to the positive electrode fluid collector surface to obtain a positive electrode sheet; (5) The positive electrode sheet from step (3) is punched to the required diameter using punching equipment.

[0132] Step 2: Manufacturing a negative electrode sheet, which specifically includes the following substeps: S1: Polytetrafluoroethylene and N-methylpyrrolidone are thoroughly mixed in a mass ratio of 0.4 to obtain a negative electrode paste solution; S2: Add SP and CNT to the negative electrode paste solution and mix evenly to obtain a negative electrode conductive paste solution. The mixing is performed by stirring, with the revolution speed of 15 rpm and the rotation speed of 2000 rpm. S3: Add lithium titanate to the negative electrode conductive paste liquid and mix uniformly to obtain a wet slurry, mixing is performed by stirring, the revolution speed of the stirring mixer is 15 rpm, and the rotation speed is 2000 rpm; S4: The wet slurry is applied to the surface of the negative electrode current collector to obtain a negative electrode sheet. S5: The negative electrode sheet from step S4 is punched out to the required diameter using punching equipment. Step 3: Assemble the positive electrode sheet, separator, and negative electrode sheet by stacking them, place them in the housing 6, and then inject an electrolyte into the housing 6 and package it to obtain an ultra-thin supercapacitor.

[0133] Example 8 This example provides an ultra-thin supercapacitor, and is different from Example 1 in that the specific surface area of ​​the activated carbon added during the manufacturing process of the polar sheet is 1200 m 2 / g, and the other structures, manufacturing methods, materials and their ratios were all the same as in Example 1.

[0134] Example 9 This example provides an ultra-thin supercapacitor, and is different from Example 1 in that the specific surface area of ​​the activated carbon added during the manufacturing process of the positive electrode sheet is 2200 m 2 / g, and the other structures, manufacturing methods, materials and their ratios are all the same as in Example 1.

[0135] Example 10 This example provides an ultra-thin supercapacitor, model number 2023, with a diameter of 20 mm and a thickness of 3.2 mm. As shown in FIG. 2, the supercapacitor includes a stainless steel housing 6 and a top cover 5. The housing 6 is insulated from the top cover 5 via an insulating rubber ring 4, forming a receiving chamber. A positive electrode sheet, a separator 3, and a negative electrode sheet are stacked in this order from the bottom of the housing 6 toward the top cover 5. The positive electrode sheet includes a first active material layer 1 with a diameter of 15.8 mm and a thickness of 10 μm, which includes lithium cobalt oxide, activated carbon, SP, CNT, and polytetrafluoroethylene. The negative electrode sheet includes a second active material layer 2 with a diameter of 15.8 mm and a thickness of 10 μm, which includes lithium titanate, SP, CNT, and polytetrafluoroethylene. The separator 3 is a glass fiber separator 3, and the housing 6 is further filled with an electrolyte, which includes LiPF6, EC, DMC, and EMC.

[0136] In addition, this embodiment provides a method for manufacturing the above-mentioned ultra-thin supercapacitor, which specifically includes the following steps:

[0137] Step 1: Manufacturing a positive electrode plate, which specifically includes the following substeps: (1) Lithium cobalt oxide, specific surface area 1600m 2 / g of activated carbon, SP, CNT, and polytetrafluoroethylene were thoroughly mixed in a mass ratio of 71:20:4:1:4, and the mixture was stirred to obtain a dry powder of a positive electrode material. The revolution speed of the stirring mixture was 15 rpm and the rotation speed was 2000 rpm. (2) The dried powder of the positive electrode material obtained in step (1) is formed into a positive electrode plate by thermocompression, the thermocompression temperature being 250°C; (3) The positive electrode sheet from step (2) is punched to the required diameter using punching equipment.

[0138] Step 2: Manufacturing a negative electrode sheet, which specifically includes the following substeps: S1: Lithium titanate, SP, CNT, and polytetrafluoroethylene were thoroughly mixed in a mass ratio of 91:4:1:4 to obtain a dry powder of a negative electrode material. S2: The dry powder of the negative electrode material obtained in step S1 is formed into a negative electrode sheet by thermocompression bonding. S3: The negative electrode sheet from step S2 is punched out to the required diameter using punching equipment. Step 3: Assemble the positive electrode sheet, separator 3 and negative electrode sheet by stacking them, place them in a housing 6, inject an electrolyte into the housing 6 and package them to obtain an ultra-thin supercapacitor.

[0139] Comparative Example 1 This comparative example provides an ultra-thin supercapacitor, and is different from Example 1 in that the first active material layer 1 of the positive electrode sheet has a specific surface area of ​​1600 m 2 / g of activated carbon was not added, and the other structures, manufacturing methods, materials and their ratios were all the same as in Example 1.

[0140] Comparative Example 2 This comparative example provides a supercapacitor, and is different from Comparative Example 1 in that the structure of the ultra-thin supercapacitor of this comparative example is such that multiple layers of positive and negative electrode sheets are stacked alternately from bottom to top inside the housing and top cover of this comparative example, separators are installed between adjacent positive and negative electrode sheets, the bottom layer is a positive electrode sheet used to connect the housing, and the top layer is a negative electrode sheet used to connect the top cover. The other structures, manufacturing methods, materials, and proportions are all the same as those of Example 1.

[0141] In the present invention, the supercapacitors with ultra-thin steel housings in Examples 1 to 10 and Comparative Examples 1 and 2 were subjected to a capacity test, a cycle performance test, and a self-discharge test. The test results are shown in Table 1.

[0142] Here, the capacity test conditions are as follows: first, charge at a constant current and constant voltage of 1C, cut-off current is 0.2C, then discharge at 2C, and record the discharge capacity. For the cycle test, discharge at 1C current for 5 seconds. hand 10,000 cycles. Self-discharge test is measured by leakage current.

[0143] Table 1 JPEG2026000839000002.jpg85163

[0144] As can be seen from Table 1, the ultra-thin supercapacitors in Examples 1 to 10 of the present invention have high capacity and cycle retention rate, low leakage current, which is advantageous for ensuring driving range, and also improves the safety performance of the capacitor.

[0145] Compared to Example 1, the performance of the capacitors in Examples 8 and 9 was slightly lower. This was mainly due to the difference in the specific surface area of ​​the activated carbon added to the active material of the positive electrode sheet. The specific surface area of ​​the activated carbon added in Example 8 was too small, which was unfavorable for the formation of an electric double layer structure and reduced the multiplier output capacity. On the other hand, the specific surface area of ​​the activated carbon added in Example 9 was too large, which reduced the cycle performance and multiplier performance with lithium cobalt oxide, further reducing overall performance.

[0146] As shown in Table 1, the cycle retention rate of the supercapacitor in Example 1 is higher than that in Comparative Example 1. This is mainly because Example 1 adds a porous activated carbon with a high specific surface area to the active material of the positive electrode sheet, creating an electric double layer structure in the positive electrode of the capacitor, improving the capacitor's multiplier output capacity. The capacitor capacity of Comparative Example 2 is lower than that of Example 1, and the leakage current is increased. The multilayer laminate structure used in Comparative Example 2 increases the thickness of the capacitor, which is unfavorable for the application in ultra-thin terminal products.

[0147] The applicant declares that the above is only a specific embodiment of the present invention, and the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present invention are obviously within the protection scope and disclosure scope of the present invention. [Explanation of symbols]

[0148] 1 - first active material layer, 2 - second active material layer, 3 - separator, 4 - insulating rubber ring, 5 - upper cover body, 6 - shell, 7 - positive electrode current collector, 8 - negative electrode current collector

Claims

1. The battery is characterized by comprising a first active material layer including a positive electrode active material, a carbon electrode material, a positive electrode conductive agent, and a positive electrode binder. Positive electrode sheet for capacitors.

2. the carbon electrode material is a porous carbon electrode material, The porous carbon electrode material preferably contains porous activated carbon and / or biomass carbon, The porous carbon electrode material has a specific surface area of ​​1400 to 2000 m ２ / g, The porous carbon electrode material preferably has a median particle size of 3 to 10 μm. The positive electrode sheet for a capacitor according to claim 1 .

3. The total mass of the first active material layer is 100%, and the mass fraction of the positive electrode active material is 50 to 94%; the mass fraction of the positive electrode conductive agent is 1 to 10%; The mass fraction of the positive electrode binder is 2 to 10%, the mass fraction of the carbon electrode material is 3 to 50%; The positive electrode active material preferably includes a lithium-containing compound, and the lithium-containing compound preferably includes any one or a combination of at least two of a layered transition metal oxide, a polyanion compound, or a spinel compound; The layered transition metal oxide is LiMO ２ wherein M preferably comprises any one or a combination of at least two of Co, Ni, or Mn; The polyanionic compound is LiFePO ４ and / or (LiMn ｘ Fe １－ｘ P.O. ４ ), wherein x is preferably 0.1 to 0.6; The spinel compound preferably contains lithium manganate, The positive electrode conductive agent preferably includes any one or a combination of at least two of conductive carbon black, carbon nanotubes, graphene, or carbon fiber conductive agents, The specific surface area of ​​the positive electrode conductive agent is 40 to 100 m ２ / g, The median particle size of the positive electrode conductive agent is preferably 10 to 100 nm, The positive electrode binder preferably contains any one or a combination of at least two of polyvinylidene fluoride, polytetrafluoroethylene, and polyacrylic acid. The positive electrode sheet for a capacitor according to claim 1 .

4. The positive electrode sheet for a capacitor further includes a positive electrode current collector, and the first active material layer is provided on at least one surface of the positive electrode current collector, The thickness of the positive electrode current collector is preferably 6 to 20 μm, The positive electrode current collector preferably includes aluminum foil or aluminum mesh. The positive electrode sheet for a capacitor according to claim 1 .

5. The manufacturing method includes mixing a positive electrode active material, a carbon electrode material, a positive electrode conductive agent, and a positive electrode binder to obtain a positive electrode material, and processing and shaping the obtained positive electrode material to obtain a first active material layer. A method for producing the positive electrode sheet for a capacitor according to claim 1.

6. The mixing includes dry mixing or wet mixing, When the thickness of the positive electrode sheet for a capacitor is greater than 200 μm, the mixing is preferably performed by dry mixing, and when the thickness of the positive electrode sheet for a capacitor is less than or equal to 200 μm, the mixing is preferably performed by wet mixing; The manufacturing method preferably includes providing a positive electrode current collector and combining the positive electrode material and the positive electrode current collector so as to form a first active material layer on at least one surface of the positive electrode current collector, The combining preferably includes thermocompression bonding the positive electrode material to a surface of a positive electrode current collector, or preparing a positive electrode slurry from the positive electrode material and then applying the slurry to the surface of a positive electrode current collector, so as to form the first active material layer; The temperature for the thermocompression bonding is preferably 100 to 200°C, The positive electrode slurry is prepared by mixing a positive electrode material with a solvent, and the mass ratio of the positive electrode material to the solvent is preferably 0.4 to 0.

8. The method of claim 5.

7. The capacitor includes a housing and an upper cover body that are insulated and connected to each other, the housing and the upper cover body forming a receiving chamber, a positive electrode sheet, a separator, and a negative electrode sheet being sequentially stacked in the receiving chamber, the positive electrode sheet being connected to the housing, and the negative electrode sheet being at least partially connected to the upper cover body, and the positive electrode sheet is the positive electrode sheet for a capacitor according to claim 1. Ultra-thin supercapacitor.

8. the positive electrode sheet further includes a positive electrode current collector disposed between the housing and the first active material layer, Preferably, the housing is also filled with an electrolyte, Preferably, the housing is connected to the top cover by an insulating assembly; The insulating assembly is preferably an insulating rubber ring. The ultra-thin supercapacitor of claim 7.

9. the negative electrode sheet includes a second active material layer including a negative electrode active material, a negative electrode conductive agent, and a negative electrode binder; It is preferable that the negative electrode sheet further includes a negative electrode current collector provided between the upper cover and the second active material layer, The negative electrode current collector preferably includes any one of copper foil, nickel mesh, aluminum foil, and aluminum mesh. The thickness of the negative electrode current collector is preferably 6 to 20 μm, It is preferable that the total mass of the second active material is 100%, and the mass fraction of the negative electrode active material is 80 to 96%; the mass fraction of the negative electrode conductive agent is 2 to 10%, and the mass fraction of the negative electrode binder is 2 to 10%, The negative electrode active material preferably contains lithium titanate and / or a carbon active material, The carbon active material preferably includes any one or a combination of at least two of graphite, soft carbon, hard carbon, or mesophase carbon microspheres; The negative electrode conductive agent preferably includes any one or a combination of at least two of conductive carbon black, carbon nanotubes, graphene, or carbon fiber conductive agents, The negative electrode binder preferably includes any one or a combination of at least two of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylic acid, sodium carboxymethyl-based cellulose, and styrene-butadiene rubber. The ultra-thin supercapacitor of claim 7.

10. the separator includes a polymer separator, a nonwoven fabric separator, or a glass fiber separator; The housing is preferably made of stainless steel. The upper cover is preferably made of stainless steel. Preferably, the material of the insulating assembly includes any one of polypropylene, polyphenylene sulfide, and polyether ether ketone; The electrolyte solution preferably contains an organic solvent and a lithium salt, The organic solvent preferably contains a carbonate-based solvent and / or an ether-based solvent, The lithium salt is LiPF ６ , LiTFSI, LiFSI, LiBOB or LiBF ４ Preferably, the composition comprises any one or a combination of at least two of the following: The ultra-thin supercapacitor of claim 7.

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