Capacitor with bipolar structure

By designing bipolar structures and current collector components in capacitors, combined with voltage equalization technology, the existing capacitors have been solved, and the combination of high energy density and high power density is achieved.

CN222851274UActive Publication Date: 2025-05-09SHANGHAI AOWEI TECH DEV
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Patent Information

Application Number
CN202421228955.8
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-05-31
Publication Date
2025-05-09
Estimated Expiration
2034-05-31

AI Technical Summary

Technical Problem

Existing capacitors have poor consistency, short life, low reliability, and it is difficult to achieve high energy density and high power density at the same time.

Method used

A capacitor with a bipolar structure is designed, and through the specific design of the current collector assembly, it includes stacking the first bipolar current collector, at least one first electrode layer, at least one second bipolar current collector, a second electrode layer and a third bipolar current collector, and voltage equalization is performed with the external circuit through a positive electrode ear, a balance ear and a negative electrode ear.

Benefits of technology

Improves the consistency and life of supercapacitors, improves the consistency and reliability of groups, and enhances the power and energy density of modules.

✦ Generated by Eureka AI based on patent content.

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Patent Text Reader

Abstract

The utility model provides a capacitor with a bipolar structure, which comprises a shell, a current collector assembly is arranged in the shell and comprises a first bipolar current collector, at least one first electrode layer, at least one second bipolar current collector, a second electrode layer and a third bipolar current collector which are sequentially stacked, a second bipolar current collector is arranged between every two first electrode layers; the first bipolar current collector is connected with a positive pole lug, the second bipolar current collector is connected with a balance pole lug, the third bipolar current collector is connected with a negative pole lug, the volume of the positive pole lug is the same as that of the negative pole lug, and the volume of the balance pole lug is smaller than that of the positive pole lug. According to the utility model, through the specific design of the current collector assembly, the consistency and the service life of a conventional super capacitor are improved, the consistency and the reliability of grouping are improved, and the power density and the energy density of a module are improved.
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Description

Technical Field

[0001] The utility model belongs to the technical field of capacitor design, and relates to a capacitor with a bipolar structure, in particular to a super capacitor structure with high voltage and long life. Background Art

[0002] Compared with lithium-ion battery positive electrode materials and negative electrode materials, supercapacitors tend to exhibit relatively high power density and relatively long cycle life. In other words, the release of adsorbed lithium ions from supercapacitor materials tends to be faster than the deintercalation of lithium ions from lithium-ion battery positive electrode materials and negative electrode materials. On the other hand, the positive electrode materials and negative electrode materials of lithium-ion batteries tend to exhibit relatively high energy density. This is because the positive electrode materials and negative electrode materials can generally embed a larger amount of lithium ions than can be adsorbed on the surface of a similar amount of supercapacitor materials. It is desirable to produce an electrical storage device that exhibits a combination of both high energy density and high power density.

[0003] However, the existing capacitors still have problems such as poor consistency, short life, low reliability, and incomplete display of high energy density and high power density. Therefore, it is urgent to design a bipolar structure capacitor to overcome the defects of the existing technology and meet the needs of practical applications. Utility Model Content

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a capacitor with a bipolar structure. In the present invention, the consistency and life of the existing supercapacitors are improved through the specific design of the current collector assembly, the consistency and reliability of the group are improved, and the power density and energy density of the module are improved.

[0005] To achieve this purpose, the utility model adopts the following technical solutions:

[0006] In a first aspect, the utility model provides a bipolar capacitor, the capacitor comprising a housing, a current collector assembly disposed in the housing, the current collector assembly comprising a first bipolar current collector, at least one first electrode layer, at least one second bipolar current collector, a second electrode layer and a third bipolar current collector stacked in sequence, and one second bipolar current collector is disposed between each of the first electrode layers;

[0007] The first bipolar current collector is connected to a positive electrode tab, the second bipolar current collector is connected to a balancing tab, and the third bipolar current collector is connected to a negative electrode tab. The volume of the positive electrode tab is the same as that of the negative electrode tab, and the volume of the balancing tab is smaller than that of the positive electrode tab.

[0008] In the utility model, the specific design of the current collector assembly improves the consistency and life of the existing supercapacitors, improves the consistency and reliability of the grouping, and improves the power density and energy density of the module.

[0009] It should be noted that the capacitor in the present invention is connected to an external circuit for voltage equalization before use, and can also be connected to an external circuit for voltage equalization after being used a certain number of times.

[0010] It should be noted that at least one layer in the present invention can be 1 layer, 2 layers, 3 layers, 4 layers, 5 layers, 6 layers, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable; at least one can be 1, 2, 3, 4, 5, 6 layers, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0011] It should be noted that the present invention does not specifically limit the way in which the first bipolar current collector is connected to the positive electrode tab, the way in which the second bipolar current collector is connected to the balancing tab, and the way in which the third bipolar current collector is connected to the negative electrode tab, and those skilled in the art can make adaptive adjustments according to actual conditions. Among them, the balancing tab only works when adjusting the consistency of the capacitor, and the capacitor only uses the positive and negative tabs when in use or working; by connecting the positive tab, the balancing tab, and the negative tab to the external circuit for voltage balance, the local voltage of each part of the positive and negative electrode materials in the device can be made more balanced, thereby extending the service life of the supercapacitor.

[0012] It should be noted that bipolar capacitors or bipolar batteries of traditional structures do not have balancing tabs. When the number of layers inside the device is large, the difference between the layers will further expand as the use time is extended. The second bipolar current collector of the utility model is connected with a balancing tab, which can be connected to an external circuit for voltage balance, so that the local voltages of the positive and negative electrode materials in the device can be more balanced, thereby extending the service life of the supercapacitor.

[0013] It should be noted that although the high-voltage device of the traditional structure has a balancing tab, the device actually has multiple small devices connected in series. Each small device can be used independently. The balancing tab is connected to the positive or negative electrode of the small device. The balancing tab is the lead-out of the series structure in the middle of the small device. The high-voltage device can actually be understood as a module formed by multiple small devices connected in series. The bipolar capacitor of the utility model is actually one device, and the balancing tab is connected to the second bipolar current collector.

[0014] It should be noted that the volume relationship between the balancing tab, the positive tab and the negative tab is defined in the utility model. This is because the current passing through the balancing tab is small when performing voltage balancing, and does not require a large volume, while the positive tab and the negative tab are the working tabs when the capacitor is used, and the power and usage rate of the capacitor are greater than that of the battery, and the current passing through is large, so sufficient volume is required to ensure the charge carrying capacity and reduce the heat generation during use, thereby extending the service life. Furthermore, when there are many layers in the middle of the capacitor, it is limited by the area of ​​one side of the capacitor tab. If the volume of the balancing tab increases, the volume of the positive and negative tabs can only be reduced, and the current capacity of the capacitor will be reduced.

[0015] As a preferred technical solution of the present utility model, the first electrode layer and the second electrode layer are the same.

[0016] As a preferred technical solution of the utility model, the first electrode layer includes a positive electrode film, a solid electrolyte and a negative electrode film which are stacked in sequence in a direction away from the first bipolar current collector.

[0017] Preferably, the positive electrode film comprises lithium metal oxide, porous carbon, a conductive agent, a lithium salt, an inorganic solid electrolyte and an organic polymer.

[0018] Preferably, the lithium metal oxide includes any one of lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, lithium nickel oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide and lithium manganese iron phosphate, or a combination of at least two or more thereof.

[0019] Preferably, the porous carbon includes any one of activated carbon, carbon nanotubes, mesoporous carbon, carbon aerogel, skeleton carbon and graphene, or a combination of at least two or more thereof.

[0020] Preferably, the conductive agent includes any one of carbon black, acetylene black, conductive graphite, vapor-grown carbon fiber, carbon nanotube and graphene, or a combination of at least two or more thereof.

[0021] Preferably, the lithium salt includes at least one of LiPF6, LiAsF6, LiClO4, LiBF6, LiN(CF3SO3)2, LiCF3SO3, LiC(CF3SO3)2 and LiN(C4F9SO2)(CF3SO3).

[0022] Preferably, the inorganic solid electrolyte includes at least one of lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, lithium aluminum titanium phosphate, lithium zirconium silicon phosphide, lithium-rich antiperovskite material, Li2ZrCl6, Li3TiCl6, Li6PS5Cl, Li2S-GeS2, Li2S-P2S5, Li2S-SiS2 and Li2S-MeS2-P2S5.

[0023] Preferably, the organic polymer includes at least one of polyvinylidene fluoride, polyethylene oxide, polyether, polymethyl methacrylate, polyimide, polyvinylidene fluoride-hexafluoropropylene copolymer and polyacrylonitrile.

[0024] Preferably, taking the total mass of the positive electrode film as 100%, the mass of the lithium metal oxide in the positive electrode film is 10 to 90 wt.%, for example, it can be 10 wt.%, 20 wt.%, 30 wt.%, 40 wt.%, 50 wt.%, 60 wt.%, 70 wt.%, 80 wt.%, 90 wt.%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] Preferably, the mass of the porous carbon is 5 to 85wt.%, for example, it can be 5wt.%, 10wt.%, 15wt.%, 20wt.%, 25wt.%, 30wt.%, 35wt.%, 40wt.%, 45wt.%, 50wt.%, 55wt.%, 60wt.%, 65wt.%, 70wt.%, 75wt.%, 80wt.%, 85wt.%, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0026] Preferably, the mass of the conductive agent is 0.5-5wt.%, for example, it can be 0.5wt.%, 1wt.%, 1.5wt.%, 2wt.%, 2.5wt.%, 3wt.%, 3.5wt.%, 4wt.%, 4.5wt.%, 5wt.%, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the mass of the lithium salt is 0.5-5wt.%, for example, it can be 0.5wt.%, 1wt.%, 1.5wt.%, 2wt.%, 2.5wt.%, 3wt.%, 3.5wt.%, 4wt.%, 4.5wt.%, 5wt.%, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] Preferably, the mass of the inorganic solid electrolyte is 3 to 20 wt.%, for example, it can be 3 wt.%, 5 wt.%, 10 wt.%, 12 wt.%, 14 wt.%, 16 wt.%, 18 wt.%, 20 wt.%, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] Preferably, the mass of the organic polymer is 1 to 10 wt.%, for example, it can be 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] Preferably, the solid electrolyte comprises an organic polymer, an inorganic solid electrolyte and a lithium salt.

[0031] Preferably, the organic polymer includes at least one of polyvinylidene fluoride, polyethylene oxide, polyether, polymethyl methacrylate, polyimide, polyvinylidene fluoride-hexafluoropropylene copolymer and polyacrylonitrile.

[0032] Preferably, the inorganic solid electrolyte includes at least one of lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, lithium aluminum titanium phosphate, lithium zirconium silicon phosphide, lithium-rich antiperovskite material, Li2ZrCl6, Li3TiCl6, Li6PS5Cl, Li2S-GeS2, Li2S-P2S5, Li2S-SiS2 and Li2S-MeS2-P2S5.

[0033] Preferably, the lithium salt includes at least one of LiPF6, LiAsF6, LiClO4, LiBF6, LiN(CF3SO3)2, LiCF3SO3, LiC(CF3SO3)2 and LiN(C4F9SO2)(CF3SO3).

[0034] Preferably, taking the total mass of the solid electrolyte as 100%, the mass of the organic polymer in the solid electrolyte is 5 to 20 wt.%, for example, it may be 5 wt.%, 10 wt.%, 12 wt.%, 14 wt.%, 16 wt.%, 18 wt.%, 20 wt.%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the mass of the inorganic solid electrolyte is 70 to 94 wt.%, for example, it can be 70 wt.%, 73 wt.%, 76 wt.%, 78 wt.%, 80 wt.%, 82 wt.%, 85 wt.%, 88 wt.%, 90 wt.%, 92 wt.%, 94 wt.%, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the mass of the lithium salt is 1 to 10 wt.%, for example, it can be 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the negative electrode film comprises a negative electrode active material, a conductive agent, a lithium salt, an inorganic solid electrolyte and an organic polymer.

[0038] Preferably, the negative electrode active material includes any one of activated carbon, lithium titanate, hard carbon, soft carbon, graphite and mesophase carbon microspheres, or a combination of at least two or more thereof.

[0039] Preferably, the conductive agent includes any one of carbon black, acetylene black, conductive graphite, vapor-grown carbon fiber, carbon nanotube and graphene, or a combination of at least two or more thereof.

[0040] Preferably, the lithium salt includes at least one of LiPF6, LiAsF6, LiClO4, LiBF6, LiN(CF3SO3)2, LiCF3SO3, LiC(CF3SO3)2 and LiN(C4F9SO2)(CF3SO3).

[0041] Preferably, the inorganic solid electrolyte includes at least one of lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, lithium aluminum titanium phosphate, lithium zirconium silicon phosphide, lithium-rich antiperovskite material, Li2ZrCl6, Li3TiCl6, Li6PS5Cl, Li2S-GeS2, Li2S-P2S5, Li2S-SiS2 and Li2S-MeS2-P2S5.

[0042] Preferably, the organic polymer includes at least one of polyvinylidene fluoride, polyethylene oxide, polyether, polymethyl methacrylate, polyimide, polyvinylidene fluoride-hexafluoropropylene copolymer and polyacrylonitrile.

[0043] Preferably, taking the total mass of the negative electrode film as 100%, in the negative electrode film, the mass of the negative electrode active material is 60 to 95 wt.%, for example, it can be 60 wt.%, 65 wt.%, 70 wt.%, 75 wt.%, 80 wt.%, 85 wt.%, 90 wt.%, 95 wt.%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] Preferably, the mass of the conductive agent is 0.5-5wt.%, for example, it can be 0.5wt.%, 1wt.%, 1.5wt.%, 2wt.%, 2.5wt.%, 3wt.%, 3.5wt.%, 4wt.%, 4.5wt.%, 5wt.%, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] Preferably, the mass of the lithium salt is 0.5-5wt.%, for example, it can be 0.5wt.%, 1wt.%, 1.5wt.%, 2wt.%, 2.5wt.%, 3wt.%, 3.5wt.%, 4wt.%, 4.5wt.%, 5wt.%, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] Preferably, the mass of the inorganic solid electrolyte is 3 to 20 wt.%, for example, it can be 3 wt.%, 5 wt.%, 10 wt.%, 12 wt.%, 14 wt.%, 16 wt.%, 18 wt.%, 20 wt.%, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] Preferably, the mass of the organic polymer is 1 to 10 wt.%, for example, it can be 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0048] As a preferred technical solution of the present invention, the first bipolar current collector and the second bipolar current collector are the same.

[0049] As a preferred technical solution of the present invention, the second bipolar current collector and the third bipolar current collector are made of the same material.

[0050] As a preferred technical solution of the utility model, the first bipolar current collector is a copper-aluminum alloy current collector, a titanium current collector, a stainless steel current collector, a nickel current collector or an aluminum-nickel alloy current collector.

[0051] As a preferred technical solution of the utility model, the first bipolar current collector is pre-treated by acid washing and / or alkali washing.

[0052] As a preferred technical solution of the present invention, the second bipolar current collector is pre-treated by acid washing and / or alkali washing.

[0053] As a preferred technical solution of the present invention, the third bipolar current collector is pre-treated by acid washing and / or alkali washing.

[0054] It should be noted that the acid washing and / or alkaline washing pretreatment method adopted in the utility model can increase the roughness of the bipolar current collector, improve the adhesion of the electrode film, and reduce the peeling of the electrode material and the current collector caused by the asymmetry of the two sides of the bipolar current collector, thereby increasing the life of the bipolar capacitor.

[0055] As a preferred technical solution of the present invention, a seal is provided between the current collector assembly and the shell.

[0056] As a preferred technical solution of the utility model, the sealing member is an insulating sealing frame.

[0057] It should be noted that the seal provided in the utility model can prevent mutual leakage and liquid connection of capacitor units, improve the overall performance of the supercapacitor, and extend the service life of the supercapacitor. Among them, the material of the insulating sealing frame can be polyethylene terephthalate, polypropylene, polyimide, etc.

[0058] Compared with the prior art, the beneficial effects of the utility model are:

[0059] (1) Through the bipolar structure design, the working voltage can be adjusted by setting the number of internal layers. The working voltage of the capacitor is equivalent to the voltage after multiple conventional capacitors are connected in series. It has strong compatibility in voltage, structure, and grouping, and can be applied to more fields.

[0060] (2) The bipolar structure design is adopted, the current direction is perpendicular to the electrode, and the current only passes through a very thin bipolar current collector, which reduces the distance the current passes, thereby improving the specific power of the solid-state supercapacitor.

[0061] (3) The bipolar structure reduces the number of connectors in the supercapacitor group, making the capacitor structure more compact, thereby improving the specific energy of the solid-state capacitor.

[0062] (4) Through the coordinated design of the positive electrode tab, the negative electrode tab, and the balancing tab, it can be connected to an external circuit for voltage balance, so that the local voltage of each part of the positive electrode material and the negative electrode material in the capacitor is more balanced, thereby extending the service life of the capacitor.

[0063] (5) The solid electrolyte and insulating sealing frame prevent mutual leakage and liquid connection of capacitor units, thereby improving the overall performance of the capacitor and extending the service life of the capacitor.

[0064] (6) By pre-treating with acid washing and / or alkaline washing, the roughness of each bipolar current collector can be increased, the adhesion of the electrode film can be improved, and the peeling of the electrode material and the current collector caused by the asymmetry of the two sides of the bipolar current collector can be reduced, thereby improving the life of the capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 A front view of a capacitor with a bipolar structure provided in a specific embodiment of the utility model;

[0066] Figure 2 A top view of a capacitor with a bipolar structure provided in a specific embodiment of the utility model;

[0067] Figure 3 A cross-sectional view of a capacitor with a bipolar structure provided in a specific embodiment of the utility model;

[0068] Figure 4 A bipolar capacitor provided in a specific embodiment of the utility model includes a first electrode layer and a front view of a second bipolar current collector;

[0069] Figure 5 A top view of a capacitor having a bipolar structure including a first electrode layer and a second bipolar current collector is provided for a specific embodiment of the utility model;

[0070] Figure 6 A cross-sectional view of a capacitor having a bipolar structure including a first electrode layer and a second bipolar current collector provided in a specific embodiment of the utility model;

[0071] Figure 7 A bipolar capacitor provided in a specific embodiment of the utility model includes a front view of two first electrode layers and two second bipolar current collectors;

[0072] Figure 8 A top view of a capacitor having a bipolar structure including two first electrode layers and two second bipolar current collectors provided in a specific embodiment of the utility model;

[0073] Fig. 9 A cross-sectional view of a capacitor having a bipolar structure including two first electrode layers and two second bipolar current collectors provided in a specific embodiment of the utility model;

[0074] Fig.10 A schematic diagram of the structure of a capacitor with a conventional structure provided in Comparative Example 1;

[0075] Among them, 100-shell; 200-positive electrode tab; 300-negative electrode tab; 400-balance tab; 500-insulating sealing frame; 600-a first electrode layer and a second bipolar current collector;

[0076] 101 - positive electrode film; 102 - solid electrolyte; 103 - negative electrode film; 104 - second bipolar current collector; 105 - first bipolar current collector; 106 - third bipolar current collector. DETAILED DESCRIPTION

[0077] It should be understood that, in the description of the present utility model, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0078] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0079] Those skilled in the art should understand that the utility model must include necessary pipelines, conventional valves and general pump equipment for realizing a complete process, but the above content does not belong to the main utility model points of the utility model. Those skilled in the art can add layouts on their own based on the process flow and equipment structure selection, and the utility model does not make special requirements and specific limitations on this.

[0080] The technical solution of the utility model is further explained below with reference to the accompanying drawings and through specific implementation methods.

[0081] In a specific embodiment, the utility model provides a bipolar structure capacitor, such as Figure 1 , Figure 2 and Figure 3 As shown, the capacitor includes a shell 100, in which a current collector assembly is arranged, and the current collector assembly includes a first bipolar current collector 105, at least one first electrode layer, at least one second bipolar current collector 104, a second electrode layer and a third bipolar current collector 106 which are stacked in sequence, and a second bipolar current collector 104 is arranged between each first electrode layer; the first bipolar current collector 105 is connected to a positive electrode tab 200, the second bipolar current collector 104 is connected to a balancing tab 400, and the third bipolar current collector 106 is connected to a negative electrode tab 300, the volume of the positive electrode tab 200 is the same as the volume of the negative electrode tab 300, and the volume of the balancing tab 400 is smaller than the volume of the positive electrode tab 200.

[0082] In the utility model, the specific design of the current collector assembly improves the consistency and life of the existing supercapacitors, improves the consistency and reliability of the grouping, and improves the power density and energy density of the module.

[0083] It should be noted that at least one layer in the present invention can be 1 layer, 2 layers, 3 layers, 4 layers, 5 layers, 6 layers, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable; at least one can be 1, 2, 3, 4, 5, 6 layers, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0084] It should be noted that the present invention does not specifically limit the way in which the first bipolar current collector 105 is connected to the positive electrode tab 200, the way in which the second bipolar current collector 104 is connected to the balancing tab 400, and the way in which the third bipolar current collector 106 is connected to the negative electrode tab 300, and those skilled in the art can make adaptive adjustments according to actual conditions. Among them, the balancing tab 400 only works when adjusting the consistency of the capacitor, and the capacitor only uses the positive electrode tab 200 and the negative electrode tab 300 when in use or working; by connecting the positive electrode tab 200, the balancing tab 400, and the negative electrode tab 300 to the external circuit for voltage balance, the local voltage of each part of the positive electrode material and the negative electrode material in the device can be made more balanced, thereby extending the service life of the supercapacitor.

[0085] Further, the first electrode layer and the second electrode layer are the same.

[0086] Furthermore, the first electrode layer includes a positive electrode film 101 , a solid electrolyte 102 , and a negative electrode film 103 which are sequentially stacked in a direction away from the first bipolar current collector 105 .

[0087] Further, the positive electrode film 101 includes lithium metal oxide, porous carbon, a conductive agent, a lithium salt, an inorganic solid electrolyte 102 and an organic polymer.

[0088] Furthermore, the lithium metal oxide includes any one of lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, lithium nickel oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide and lithium manganese iron phosphate, or a combination of at least two or more thereof.

[0089] Furthermore, the porous carbon includes any one of activated carbon, carbon nanotubes, mesoporous carbon, carbon aerogel, skeleton carbon and graphene, or a combination of at least two or more thereof.

[0090] Furthermore, the conductive agent includes any one of carbon black, acetylene black, conductive graphite, vapor-grown carbon fiber, carbon nanotube and graphene, or a combination of at least two or more thereof.

[0091] Further, the lithium salt includes at least one of LiPF6, LiAsF6, LiClO4, LiBF6, LiN(CF3SO3)2, LiCF3SO3, LiC(CF3SO3)2 and LiN(C4F9SO2)(CF3SO3).

[0092] Furthermore, the inorganic solid electrolyte 102 includes at least one of lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, lithium aluminum titanium phosphate, lithium zirconium silicon phosphide, lithium-rich antiperovskite material, Li2ZrCl6, Li3TiCl6, Li6PS5Cl, Li2S-GeS2, Li2S-P2S5, Li2S-SiS2 and Li2S-MeS2-P2S5.

[0093] Further, the organic polymer includes at least one of polyvinylidene fluoride, polyethylene oxide, polyether, polymethyl methacrylate, polyimide, polyvinylidene fluoride-hexafluoropropylene copolymer and polyacrylonitrile.

[0094] Furthermore, taking the total mass of the positive electrode film 101 as 100%, the mass of lithium metal oxide in the positive electrode film 101 is 10 to 90 wt.%, for example, it can be 10 wt.%, 20 wt.%, 30 wt.%, 40 wt.%, 50 wt.%, 60 wt.%, 70 wt.%, 80 wt.%, 90 wt.%, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0095] Furthermore, the mass of the porous carbon is 5 to 85wt.%, for example, it can be 5wt.%, 10wt.%, 15wt.%, 20wt.%, 25wt.%, 30wt.%, 35wt.%, 40wt.%, 45wt.%, 50wt.%, 55wt.%, 60wt.%, 65wt.%, 70wt.%, 75wt.%, 80wt.%, 85wt.%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0096] Furthermore, the mass of the conductive agent is 0.5 to 5wt.%, for example, it can be 0.5wt.%, 1wt.%, 1.5wt.%, 2wt.%, 2.5wt.%, 3wt.%, 3.5wt.%, 4wt.%, 4.5wt.%, 5wt.%, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0097] Furthermore, the mass of lithium salt is 0.5-5wt.%, for example, it can be 0.5wt.%, 1wt.%, 1.5wt.%, 2wt.%, 2.5wt.%, 3wt.%, 3.5wt.%, 4wt.%, 4.5wt.%, 5wt.%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0098] Furthermore, the mass of the inorganic solid electrolyte 102 is 3 to 20 wt.%, for example, it can be 3 wt.%, 5 wt.%, 10 wt.%, 12 wt.%, 14 wt.%, 16 wt.%, 18 wt.%, 20 wt.%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0099] Furthermore, the mass of the organic polymer is 1 to 10 wt.%, for example, it can be 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0100] Furthermore, the solid electrolyte 102 includes an organic polymer, an inorganic solid electrolyte 102 and a lithium salt.

[0101] Further, the organic polymer includes at least one of polyvinylidene fluoride, polyethylene oxide, polyether, polymethyl methacrylate, polyimide, polyvinylidene fluoride-hexafluoropropylene copolymer and polyacrylonitrile.

[0102] Furthermore, the inorganic solid electrolyte 102 includes at least one of lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, lithium aluminum titanium phosphate, lithium zirconium silicon phosphide, lithium-rich antiperovskite material, Li2ZrCl6, Li3TiCl6, Li6PS5Cl, Li2S-GeS2, Li2S-P2S5, Li2S-SiS2 and Li2S-MeS2-P2S5.

[0103] Further, the lithium salt includes at least one of LiPF6, LiAsF6, LiClO4, LiBF6, LiN(CF3SO3)2, LiCF3SO3, LiC(CF3SO3)2 and LiN(C4F9SO2)(CF3SO3).

[0104] Furthermore, taking the total mass of the solid electrolyte 102 as 100%, the mass of the organic polymer in the solid electrolyte 102 is 5 to 20 wt.%, for example, it can be 5 wt.%, 10 wt.%, 12 wt.%, 14 wt.%, 16 wt.%, 18 wt.%, 20 wt.%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0105] Furthermore, the mass of the inorganic solid electrolyte 102 is 70 to 94 wt.%, for example, it can be 70 wt.%, 73 wt.%, 76 wt.%, 78 wt.%, 80 wt.%, 82 wt.%, 85 wt.%, 88 wt.%, 90 wt.%, 92 wt.%, 94 wt.%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0106] Furthermore, the mass of the lithium salt is 1 to 10 wt.%, for example, it can be 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0107] Furthermore, the negative electrode film 103 includes a negative electrode active material, a conductive agent, a lithium salt, an inorganic solid electrolyte 102 and an organic polymer.

[0108] Furthermore, the negative electrode active material includes any one of activated carbon, lithium titanate, hard carbon, soft carbon, graphite and mesophase carbon microspheres, or a combination of at least two or more thereof.

[0109] Furthermore, the conductive agent includes any one of carbon black, acetylene black, conductive graphite, vapor-grown carbon fiber, carbon nanotube and graphene, or a combination of at least two or more thereof.

[0110] Further, the lithium salt includes at least one of LiPF6, LiAsF6, LiClO4, LiBF6, LiN(CF3SO3)2, LiCF3SO3, LiC(CF3SO3)2 and LiN(C4F9SO2)(CF3SO3).

[0111] Furthermore, the inorganic solid electrolyte 102 includes at least one of lithium lanthanum zirconium oxide, lithium lanthanum titanium oxide, lithium aluminum titanium phosphate, lithium zirconium silicon phosphide, lithium-rich antiperovskite material, Li2ZrCl6, Li3TiCl6, Li6PS5Cl, Li2S-GeS2, Li2S-P2S5, Li2S-SiS2 and Li2S-MeS2-P2S5.

[0112] Further, the organic polymer includes at least one of polyvinylidene fluoride, polyethylene oxide, polyether, polymethyl methacrylate, polyimide, polyvinylidene fluoride-hexafluoropropylene copolymer and polyacrylonitrile.

[0113] Furthermore, taking the total mass of the negative electrode film 103 as 100%, the mass of the negative electrode active material in the negative electrode film 103 is 60 to 95 wt.%, for example, it can be 60 wt.%, 65 wt.%, 70 wt.%, 75 wt.%, 80 wt.%, 85 wt.%, 90 wt.%, 95 wt.%, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0114] Furthermore, the mass of the conductive agent is 0.5 to 5wt.%, for example, it can be 0.5wt.%, 1wt.%, 1.5wt.%, 2wt.%, 2.5wt.%, 3wt.%, 3.5wt.%, 4wt.%, 4.5wt.%, 5wt.%, etc., but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0115] Furthermore, the mass of lithium salt is 0.5-5wt.%, for example, it can be 0.5wt.%, 1wt.%, 1.5wt.%, 2wt.%, 2.5wt.%, 3wt.%, 3.5wt.%, 4wt.%, 4.5wt.%, 5wt.%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0116] Furthermore, the mass of the inorganic solid electrolyte 102 is 3 to 20 wt.%, for example, it can be 3 wt.%, 5 wt.%, 10 wt.%, 12 wt.%, 14 wt.%, 16 wt.%, 18 wt.%, 20 wt.%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0117] Furthermore, the mass of the organic polymer is 1 to 10 wt.%, for example, it can be 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0118] Further, the first bipolar current collector 105 and the second bipolar current collector 104 are the same.

[0119] Further, the second bipolar current collector 104 and the third bipolar current collector 106 are the same.

[0120] Furthermore, the first bipolar current collector 105 is a copper-aluminum alloy current collector, a titanium current collector, a stainless steel current collector, a nickel current collector or an aluminum-nickel alloy current collector.

[0121] Furthermore, the first bipolar current collector 105 is pre-treated by acid washing and / or alkali washing.

[0122] Furthermore, the second bipolar current collector 104 is pre-treated by acid washing and / or alkali washing.

[0123] Furthermore, the third bipolar current collector 106 is pre-treated by acid washing and / or alkali washing.

[0124] It should be noted that the acid washing and / or alkaline washing pretreatment method adopted in the utility model can increase the roughness of the bipolar current collector, improve the adhesion of the electrode film, and reduce the peeling of the electrode material and the current collector caused by the asymmetry of the two sides of the bipolar current collector, thereby increasing the life of the bipolar capacitor.

[0125] Furthermore, a seal is provided between the current collector assembly and the housing 100 .

[0126] Furthermore, the sealing member is an insulating sealing frame 500 .

[0127] It should be noted that the seal provided in the present invention can prevent mutual leakage and liquid connection of capacitor units, thereby improving the overall performance of the supercapacitor and extending the service life of the supercapacitor.

[0128] Example 1

[0129] This embodiment provides a bipolar capacitor, such as Figure 4 , Figure 5 and Figure 6 As shown, where:

[0130] The capacitor includes a shell 100, in which a current collector assembly is arranged, and the current collector assembly includes a first bipolar current collector 105, a first electrode layer and a second bipolar current collector 600, a second electrode layer and a third bipolar current collector 106 which are stacked in sequence; the first bipolar current collector 105 is connected to a positive electrode tab 200, the second bipolar current collector 104 is connected to a balancing tab 400, and the third bipolar current collector 106 is connected to a negative electrode tab 300, the volume of the positive electrode tab 200 is the same as the volume of the negative electrode tab 300, and the volume of the balancing tab 400 is smaller than the volume of the positive electrode tab 200.

[0131] The first electrode layer is the same as the second electrode layer. The first electrode layer includes a positive electrode film 101 , a solid electrolyte 102 , and a negative electrode film 103 which are sequentially stacked in a direction away from the first bipolar current collector 105 .

[0132] The positive electrode film 101 includes lithium cobalt oxide, lithium iron phosphate, activated carbon, carbon black, LiPF6 and LiAsF6, lithium lanthanum zirconium oxide and polyvinylidene fluoride. Taking the total mass of the positive electrode film 101 as 100%, in the positive electrode film 101, the mass of lithium cobalt oxide and lithium iron phosphate is 80wt.%, the mass of activated carbon is 5wt.%, the mass of carbon black is 0.5wt.%, the mass of LiPF6 and LiAsF6 is 3.5wt.%, the mass of lithium lanthanum zirconium oxide is 3wt.%, and the mass of polyvinylidene fluoride is 8wt.%.

[0133] The solid electrolyte 102 includes polyethylene oxide, lithium lanthanum titanium oxide, LiClO4, and LiBF6. Taking the total mass of the solid electrolyte 102 as 100%, the mass of the organic polymer in the solid electrolyte 102 is 15wt.%, the mass of the inorganic solid electrolyte 102 is 80wt.%, and the mass of the lithium salt is 5wt.%.

[0134] The negative electrode film 103 includes lithium titanate, acetylene black, LiBF6, a lithium-rich antiperovskite material, and polyethylene oxide. Taking the total mass of the negative electrode film 103 as 100%, in the negative electrode film 103, the mass of lithium titanate is 80wt.%, the mass of acetylene black is 3wt.%, the mass of LiBF6 is 3wt.%, the mass of lithium-rich antiperovskite material is 5wt.%, and the mass of polyethylene oxide is 9wt.%.

[0135] The first bipolar current collector 105 , the second bipolar current collector 104 and the third bipolar current collector 106 are all made of copper-aluminum alloy, and are pre-treated by acid washing. An insulating sealing frame 500 is provided between the current collector assembly and the housing 100 .

[0136] Example 2

[0137] This embodiment provides a bipolar capacitor, such as Figure 7 , Figure 8 and Fig. 9 As shown, where:

[0138] The capacitor includes a shell 100, in which a current collector assembly is arranged. The current collector assembly includes a first bipolar current collector 105, two first electrode layers, two second bipolar current collectors 104, a second electrode layer and a third bipolar current collector 106 which are stacked in sequence, and a second bipolar current collector 104 is arranged between each first electrode layer; the first bipolar current collector 105 is connected to a positive electrode tab 200, the second bipolar current collector 104 is connected to a balancing tab 400, and the third bipolar current collector 106 is connected to a negative electrode tab 300, the volume of the positive electrode tab 200 is the same as the volume of the negative electrode tab 300, and the volume of the balancing tab 400 is smaller than the volume of the positive electrode tab 200.

[0139] The first electrode layer is the same as the second electrode layer. The first electrode layer includes a positive electrode film 101 , a solid electrolyte 102 , and a negative electrode film 103 which are sequentially stacked in a direction away from the first bipolar current collector 105 .

[0140] The positive electrode film 101 includes lithium manganate, carbon nanotubes, conductive graphite, LiCF3SO3, Li3TiCl6 and polyimide. Taking the total mass of the positive electrode film 101 as 100%, in the positive electrode film 101, the mass of lithium manganate is 70wt.%, the mass of carbon nanotubes is 10wt.%, the mass of conductive graphite is 2wt.%, the mass of LiCF3SO3 is 5wt.%, the mass of Li3TiCl6 is 10wt.%, and the mass of polyimide is 3wt.%.

[0141] The solid electrolyte 102 includes polymethyl methacrylate, lithium aluminum titanium phosphate and LiPF6. Taking the total mass of the solid electrolyte 102 as 100%, the mass of polymethyl methacrylate, the mass of lithium aluminum titanium phosphate and the mass of LiPF6 in the solid electrolyte 102 are 10wt.%, 85wt.%, and 5wt.%.

[0142] The negative electrode film 103 includes graphite, graphene, LiClO4, lithium zirconium silicon phosphorus oxide and polyacrylonitrile. Taking the total mass of the negative electrode film 103 as 100%, the mass of graphite in the negative electrode film 103 is 78wt.%, the mass of graphene is 2wt.%, the mass of LiClO4 is 4wt.%, the mass of lithium zirconium silicon phosphorus oxide is 11wt.%, and the mass of polyacrylonitrile is 5wt.%.

[0143] The first bipolar current collector 105 , the second bipolar current collector 104 and the third bipolar current collector 106 are all made of aluminum-nickel alloy, and are all pre-treated by alkali washing. An insulating sealing frame 500 is provided between the current collector assembly and the housing 100 .

[0144] Example 3

[0145] This embodiment provides a capacitor with a bipolar structure. The difference from the first embodiment is that no balancing tab 400 is provided. The other parameters and conditions are the same as those of the first embodiment.

[0146] Example 4

[0147] This embodiment provides a capacitor with a bipolar structure. The difference from the first embodiment is that no seal is provided between the current collector assembly and the housing 100 . The other parameters and conditions are the same as those of the first embodiment.

[0148] Example 5

[0149] This embodiment provides a bipolar capacitor. The difference from Embodiment 1 is that Embodiment 1 is connected to an external circuit for voltage balancing before the trial production life test. Embodiment 5 is connected to an external circuit for voltage balancing before the life test and is also connected to an external circuit for voltage balancing every 2,000 charge and discharge cycles.

[0150] Comparative Example 1

[0151] This comparative example provides a bipolar capacitor. Unlike Example 1, the volume relationship between the balancing tab 400 and the positive tab 200 or the negative tab 300 is not limited. Other parameters and conditions are the same as those in Example 1.

[0152] Comparative Example 2

[0153] This comparative example provides a capacitor of conventional structure, such as Fig.10 As shown, this comparative example is equivalent to disassembling the capacitor structure of Example 1 into two independent devices, and the balance tabs 400 of the two devices can be connected by wires to form a structure similar to the positive tab 200, the balance tab 400 and the negative tab 300 of Example 1, and the operating voltage is also the same as that of Example 1.

[0154] The capacitors in the above-mentioned embodiments and comparative examples were subjected to cycle life tests. Test system: 4C current was used for 10,000 cycles of charge and discharge, the lower limit of the charge and discharge voltage was (N×2.8+2.8)V, the lower limit of the charge and discharge voltage was (N×4+4)V, the discharge capacity of the 2nd and 10,000th cycles were selected, and the retention rate of the discharge capacity of the 10,000th cycle and the discharge capacity of the 2nd cycle was calculated. Where N is the number or "number of layers" of the second current collector in the capacitor, and comparative example 2 uses the same charge and discharge voltage as embodiment 1. In addition to being connected to an external circuit for voltage equalization before the life test, embodiment 5 is also connected to an external circuit for voltage equalization every 2,000 charge and discharge cycles. Embodiment 3 does not have a balancing lug 400, and no voltage equalization is performed. The other embodiments and comparative examples only perform voltage equalization before the life test.

[0155] The results are shown in Table 1 below:

[0156] Table 1 Test results of capacitors in embodiments and comparative examples

[0157]

[0158]

[0159] From Table 1 above, we know that:

[0160] The test results of the capacitors in Examples 1 and 2 are better than those in Example 3 because the utility model sets a balancing tab 400, through which the voltage of the capacitor can be balanced, local inconsistency can be reduced, and the service life can be extended.

[0161] The test results of the capacitors in Examples 1 and 2 are better than those in Example 4 because the utility model is provided with a seal so that the layers of the capacitor will not leak and liquid-join each other, and there will be no crosstalk between the layers, thereby extending the service life of the capacitor.

[0162] The test result of the capacitor in Example 5 is slightly better than that in Example 1 because the local inconsistency inside the capacitor will expand during use. The utility model balances the voltage of the capacitor by balancing the tabs more than 400 times, which can reduce the local inconsistency and extend the service life.

[0163] The test results of the capacitors in Examples 1 and 2 are better than those in Comparative Example 1 because the utility model defines the volume relationship between the balancing tab 400 and the positive tab 200 or the negative tab 300. This is because the current passing through the balancing tab 400 is small when performing voltage balancing, and does not require a large volume, while the positive tab 200 and the negative tab 300 are the working tabs when the capacitor is used, and the power and usage rate of the capacitor are greater than that of the battery, and the current passing through is large, so sufficient volume is required to ensure the charge carrying capacity, reduce heat generation during use, and thus extend the service life. Limited by the area of ​​one side of the capacitor tab, if the volume of the balancing tab 400 increases, the volume of the positive and negative tabs 200 can only be reduced, and the current capacity of the capacitor will be reduced.

[0164] The test result of the capacitor of Example 1 is better than that of Comparative Example 2 because the charge transfer path of Example 1 is shorter than that of Comparative Example 2, so it has better power characteristics and has a longer life when charged and discharged at the same current. In addition, compared with Example 1, Comparative Example 2 increases the use of current collectors and housing 100, etc., which reduces the energy density of the capacitor.

[0165] In summary, the utility model improves the consistency and life of existing supercapacitors, improves the consistency and reliability of groups, and improves the power density and energy density of modules through the specific design of the current collector assembly.

[0166] The above description is only a specific implementation method of the present utility model, but the protection scope of the present utility model is not limited thereto. Technicians in the relevant technical field should understand that any changes or substitutions that can be easily thought of by technicians in the relevant technical field within the technical scope disclosed in the present utility model fall within the protection scope and disclosure scope of the present utility model.

Claims

1. A bipolar capacitor, characterized in that: The capacitor comprises a shell, a current collector assembly is arranged in the shell, the current collector assembly comprises a first bipolar current collector, at least one first electrode layer, at least one second bipolar current collector, a second electrode layer and a third bipolar current collector which are stacked in sequence, and one second bipolar current collector is arranged between each of the first electrode layers; The first bipolar current collector is connected to a positive electrode tab, the second bipolar current collector is connected to a balancing tab, and the third bipolar current collector is connected to a negative electrode tab. The volume of the positive electrode tab is the same as that of the negative electrode tab, and the volume of the balancing tab is smaller than that of the positive electrode tab.

2. The capacitor according to claim 1, characterized in that The first electrode layer and the second electrode layer are the same.

3. The capacitor according to claim 2, characterized in that The first electrode layer includes a positive electrode film, a solid electrolyte and a negative electrode film which are sequentially stacked in a direction away from the first bipolar current collector.

4. The capacitor according to claim 1, characterized in that The first bipolar current collector and the second bipolar current collector are the same; The second bipolar current collector is the same as the third bipolar current collector.

5. The capacitor according to claim 4, characterized in that The first bipolar current collector is a copper-aluminum alloy current collector, a titanium current collector, a stainless steel current collector, a nickel current collector or an aluminum-nickel alloy current collector.

6. The capacitor according to claim 1, characterized in that The first bipolar current collector is pre-treated by acid washing and / or alkali washing.

7. The capacitor according to claim 1, characterized in that The second bipolar current collector is pre-treated by acid washing and / or alkali washing.

8. The capacitor according to claim 1, characterized in that The third bipolar current collector is pre-treated by acid washing and / or alkali washing.

9. The capacitor according to claim 1, characterized in that A seal is provided between the current collector assembly and the housing.

10. The capacitor according to claim 9, characterized in that The sealing member is an insulating sealing frame.