Super capacitor core package and preparation method thereof, and super capacitor

Abstract

The invention relates to the technical field of capacitors, in particular to a supercapacitor core package, a preparation method thereof and a supercapacitor. The preparation method of the super capacitor core package comprises the following steps: preparing a moisture absorption electrode with the water content of 20%-30%; freezing the moisture absorption electrode to obtain a micro-ice crystal electrode; and drying the micro-ice crystal electrode, winding the micro-ice crystal electrode and a diaphragm to form a super capacitor core cladding intermediate, and fixing the super capacitor core cladding intermediate through an elastic piece to obtain the super capacitor core cladding. According to the super capacitor core package, the tail diaphragm can be prevented from being broken and damaged, the assembled super capacitor is not prone to short-circuit failure, and the self-discharge performance, the high-temperature durability and the cycling stability of the super capacitor core package are superior to those of a super capacitor assembled according to an existing process.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitors, and in particular to a supercapacitor core package, a preparation method thereof, and a supercapacitor. Background Art

[0002] Currently, there are mainly two types of commercially available supercapacitor diaphragms: cellulose diaphragms and composite diaphragms. Among them, cellulose diaphragms have become the primary choice for supercapacitors due to their advantage of not undergoing shrinkage deformation at high temperatures (≤200°C). In order to obtain better product performance, supercapacitors mostly use cellulose diaphragms as thin as possible to reduce the internal resistance of the product and increase the product capacity. However, due to the reduction of the thickness of the cellulose diaphragm, the tensile strength of the diaphragm decreases.

[0003] The assembly process of cylindrical supercapacitors includes electrode slitting, core package winding, drying, casing insertion, liquid injection, sealing, and aging processes. Among them, in the core package winding process section, it is necessary to wind the positive and negative electrodes of the supercapacitor and the cellulose diaphragm and then fix the core package. In the liquid injection process stage, the porous structures of the electrodes and the cellulose diaphragm will absorb a large amount of electrolyte. After the electrodes absorb the electrolyte, their thickness will expand. After the cellulose diaphragm absorbs the electrolyte, the tensile strength will be significantly reduced. The expanded electrodes will generate a large radial extrusion force on the wet diaphragm, causing the diaphragm to shrink and deform. If the degree of shrinkage deformation of the diaphragm exceeds the inherent deformation rate of the wet diaphragm, it will cause the tail of the cellulose diaphragm to break or be damaged, and then the positive and negative electrodes of the supercapacitor will come into contact and short-circuit. In addition, during the charging process of the supercapacitor, the positive / negative electrodes will adsorb anions / cations in the electrolyte. When a large amount of anions / cations in the electrolyte enter the activated carbon pores on the positive / negative electrodes, the thickness of the positive / negative electrodes will further expand, generating a greater radial extrusion force on the wet diaphragm in the core package and increasing the risk of the tail of the wet diaphragm breaking or being damaged, especially after the supercapacitor product undergoes long-term high-temperature load and up to one million cycles of charge and discharge tests.

[0004] In the prior art, when winding the positive and negative electrodes of a supercapacitor and a cellulose separator into a core package, there are mainly two ways to fix the separator at the tail of the core package, namely, fixing by spraying glue and fixing by pasting tape. For example, in the prior art when winding a cylindrical supercapacitor core package, glue is applied to the tail of the core package to ensure that the separator at the tail of the core package closely adheres to the core package without warping, so as to achieve the purpose of fixing the core package; and in the prior art when winding a cylindrical supercapacitor core package, in order to ensure that the wound core package does not spontaneously spread, tape is pasted to the tail of the wound core package to fix the core package. Since these two ways of fixing the separator at the tail of the supercapacitor core package cannot buffer the strong radial extrusion force generated by the thickness expansion of the wet separator after the electrode absorbs liquid and during the charging process, the assembled supercapacitor is prone to short-circuit problems caused by the fracture or damage of the tail separator. There is also prior art to suppress the defect of separator rupture caused by guide pin discharge. A carbon material layer is provided at the part where the guide pin of the supercapacitor electrode sheet is fixedly connected to the corresponding surface of the metal foil. Although it can alleviate the problem of separator rupture at the position of the guide pin in the core package, this method cannot reduce the radial extrusion force of the thickness expansion of the core package electrode after absorbing liquid and during the charging process on the tail separator, resulting in the supercapacitor being prone to tail separator damage and short-circuit failure during use. In addition, there is prior art that provides a method for repairing internal short circuits of a supercapacitor. This method uses direct current constant current charge and discharge of the supercapacitor for a short time and gradually increases the current to repair the supercapacitor. Although it has obvious effects on repairing short circuits caused by internal metal burrs, activated carbon, and direct connection of active substances at the damaged part of the separator in the supercapacitor, it cannot fundamentally solve the problem of fracture or damage of the tail separator caused by core package liquid absorption or electrode expansion during the charging process of the supercapacitor. In summary, there is currently no solution to prevent the tail separator of a supercapacitor from breaking or being damaged. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. For this reason, the present invention provides a supercapacitor core package, a preparation method thereof, and a supercapacitor. The supercapacitor core package can avoid the fracture and damage of the tail separator, and the assembled supercapacitor is not prone to short-circuit failure. Its self-discharge performance, high-temperature durability, and cycle stability are all superior to those of the supercapacitor assembled according to the existing process.

[0006] For this reason, the first aspect of the present invention provides a preparation method of a supercapacitor core package, including:

[0007] Preparing a moisture-absorbing electrode with a moisture content of 20% to 30%;

[0008] Freezing the moisture-absorbing electrode to obtain a micro-ice crystal electrode;

[0009] After drying the micro-ice crystal electrode, it is wound with a separator into an intermediate body of a supercapacitor core package, and the intermediate body of the supercapacitor core package is fixed by an elastic member to obtain the supercapacitor core package.

[0010] Aiming at the problem of the tail separator breakage or damage caused by the core package liquid absorption or the electrode expansion during the charging process of the supercapacitor assembled by the existing process, before winding the electrode and the separator into a core package, the electrode is made to absorb the humidity in the air to reach a water content of 20% - 30%, and then it is subjected to a freezing treatment so that the moisture absorbed in the electrode forms micro-ice crystals and expands to an equilibrium state, thereby ensuring that the electrode hardly expands and the thickness change is small after the subsequent electrolyte injection. At the same time, by fixing the intermediate body of the supercapacitor core package with an elastic member, the radial extrusion force on the tail separator during the subsequent liquid injection process due to the electrode liquid absorption expansion and during the charging process of the supercapacitor product due to the electrode adsorbing electrolyte ions can be buffered, fundamentally avoiding the problem of the tail separator breakage or damage of the supercapacitor core package, and greatly improving the qualified rate of the supercapacitor assembly and the product performance.

[0011] According to an embodiment of the present invention, the preparation of the moisture-absorbing electrode with a water content of 20% - 30% includes: placing the rolled electrode in an environment with a humidity of 80 - 99% RH to absorb moisture until the water content reaches 20% - 30% to obtain the moisture-absorbing electrode with a water content of 20% - 30%;

[0012] Or, placing the rolled electrode in an environment with a temperature of 50 - 90 °C and a humidity of 80 - 99% RH to absorb moisture until the water content reaches 20% - 30% to obtain the moisture-absorbing electrode with a water content of 20% - 30%.

[0013] According to an embodiment of the present invention, the thickness of the rolled electrode is 100 - 300 μm.

[0014] According to an embodiment of the present invention, in the method for preparing the moisture-absorbing electrode with a water content of 20% - 30%, the moisture absorption time is 1 - 5 h.

[0015] According to an embodiment of the present invention, the temperature of the freezing treatment is -40 - -5 °C.

[0016] According to an embodiment of the present invention, the humidity of the freezing treatment is 10 - 40% RH.

[0017] According to an embodiment of the present invention, the time of the freezing treatment is 0.5 - 3 h.

[0018] According to an embodiment of the present invention, the drying treatment method includes heat drying.

[0019] According to an embodiment of the present invention, the temperature of the drying treatment is 80 - 140 °C.

[0020] According to an embodiment of the present invention, the time of the drying treatment is 1 to 5 h.

[0021] According to an embodiment of the present invention, the tensile strength of the elastic member is 10 to 40 N.

[0022] According to an embodiment of the present invention, the elastic coefficient of the elastic member is 0.1 to 2 N / mm.

[0023] According to an embodiment of the present invention, the number of the elastic members is 1 to 5.

[0024] According to an embodiment of the present invention, the elastic member is fixed in the middle and / or at both ends of the supercapacitor core package intermediate body.

[0025] The second aspect of the present invention provides a supercapacitor core package obtained by the preparation method according to the first aspect.

[0026] Thus, the supercapacitor core package can avoid the problems of tail separator fracture and breakage, and can improve the qualification rate of supercapacitor assembly and product performance when it is used to prepare a supercapacitor.

[0027] The third aspect of the present invention provides a supercapacitor, which includes the supercapacitor core package obtained by the preparation method according to the first aspect or the supercapacitor core package according to the second aspect.

[0028] Thus, the supercapacitor is not prone to short-circuit failure, and its self-discharge performance, high-temperature durability and cycle stability are all better than those of a cylindrical supercapacitor assembled by the existing process. It can achieve a self-discharge voltage retention of more than 95% for 24 h, a high-temperature load performance of not less than 2000 h, and a cycle life of more than one million times.

[0029] The additional aspects and advantages of the present invention will be partly given in the following description, partly will become obvious from the following description, or will be understood through the practice of the present invention. Detailed Description of the Invention

[0030] The embodiments of the present invention will be described in detail below. The following described embodiments are exemplary and are only used to explain the present invention, and should not be construed as a limitation to the present invention.

[0031] It should be noted that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. Further, in the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0032] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0033] In order to make the present invention more easily understood, certain technical and scientific terms are specifically defined below. Unless otherwise clearly defined elsewhere in this document, all other technical and scientific terms used herein have the meaning commonly understood by those skilled in the art to which the present invention belongs.

[0034] In this document, the terms “include” or “comprising” are open expressions, that is, including the contents specified in the present invention, but not excluding other contents.

[0035] As used herein, the terms "optionally," "optional," or "optionally" generally mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0036] In this article, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0037] In this article, the term "tail diaphragm" generally refers to the outermost diaphragm section of the core package formed by cutting the rolled diaphragm by the winder cutter after the winding operation of the electrodes and diaphragms is completed when preparing the capacitor core package.

[0038] According to an embodiment of the present invention, a first aspect of the present invention provides a method for preparing a supercapacitor core pack, comprising:

[0039] (1) Prepare a hygroscopic electrode with a water content of 20% to 30%.

[0040] This step enables the electrode to absorb the humidity in the air. The specific implementation method is not particularly limited, and those skilled in the art can make a choice according to the situation. For example, the rolled electrode after rolling is placed in an environment with a humidity of 80-99%RH; or, the rolled electrode after rolling is placed in an environment with a temperature of 50-90°C and a humidity of 80-99%RH, so that the electrode reaches the target water content. Specifically, the rolled electrode after rolling is placed in an environment with a humidity of 80%RH, 82%RH, 84%RH, 86%RH, 88%RH, 90%RH, 92%RH, 94%RH, 96%RH, 98%RH, 99%RH or any value within the above range; or, the rolled electrode after rolling is placed in an environment with a temperature of 50°C, 60°C, 65°C, 69°C, 70°C, 80°C, 90°C or any value within the above range and a humidity of 80%RH, 82%RH, 84%RH, 86%RH, 88%RH, 90%RH, 92%RH, 94%RH, 96%RH, 98%RH, 99%RH or any value within the above range.

[0041] According to a specific embodiment of the present invention, the rolled electrode after rolling is placed in the above environment, so that the moisture-absorbing electrode reaches a water content of 20%-30%, such as 20%, 22.5%, 25%, 27.5%, 30% or any value within the above range.

[0042] According to a specific embodiment of the present invention, the time for placing the rolled electrode after rolling in the above environment is not particularly limited until the moisture-absorbing electrode reaches a water content of 20%-30%. The rolled electrode after rolling is placed in the above environment for 1-5h, such as 1h, 2h, 3h, 4h, 5h or any value within the above range.

[0043] According to a specific embodiment of the present invention, the thickness of the rolled electrode is not particularly limited. As some specific examples, the thickness of the rolled electrode can be 100-300μm, such as 100μm, 150μm, 200μm, 250μm, 300μm or any value within the above range.

[0044] According to a specific embodiment of the present invention, the material of the rolled electrode is not particularly limited, as long as it is an electrode coated with a slurry prepared with water-based. As some specific examples, the rolled electrode can be a graphite electrode, a hard carbon electrode, a soft carbon electrode, a silicon carbon electrode, an activated carbon electrode, etc.

[0045] According to specific embodiments of the present invention, the activated carbon electrode is composed of a current collector foil coated with an activated carbon paste coating on one or both sides. Among them, the current collector foil can be a metal foil such as aluminum foil, copper foil, nickel foil, titanium foil, stainless steel foil, or carbon-coated aluminum foil; the activated carbon paste includes one or more of activated carbon, conductive agent, binder, and solvent.

[0046] According to specific embodiments of the present invention, the solvent is pure water or deionized water.

[0047] According to specific embodiments of the present invention, the types of the conductive agent and the binder are not particularly limited and can be any common conductive agent and binder in the art.

[0048] According to specific embodiments of the present invention, the proportions of the above components are not particularly limited and can be mixed in any proportion.

[0049] According to specific embodiments of the present invention, the "water content" should be understood as the percentage value of the mass change amount between the mass of the electrode before drying and the mass of the electrode after drying at 150 °C until the mass no longer changes and the mass of the electrode before drying, which can be obtained by thermogravimetric analysis.

[0050] (2) Subject the moisture-absorbing electrode to a freezing treatment to obtain a micro-ice crystal electrode.

[0051] This step can cause the moisture absorbed in the aforementioned moisture-absorbing electrode to form micro-ice crystals and expand to an equilibrium state, thereby ensuring that the electrode hardly expands after the subsequent injection of the electrolyte and the change in the electrode thickness is small.

[0052] According to specific embodiments of the present invention, the temperature of the freezing treatment is not particularly limited, and those skilled in the art can select according to the situation. As some specific examples, the temperature of the freezing treatment is -40 to -5 °C, such as -5 °C, -10 °C, -15 °C, -20 °C, -25 °C, -30 °C, -35 °C, -40 °C, or any value within the above range.

[0053] According to specific embodiments of the present invention, the humidity of the freezing treatment is not particularly limited, and those skilled in the art can select according to the situation. As some specific examples, the humidity of the freezing treatment is 10 to 40% RH, such as 10% RH, 20% RH, 30% RH, 40% RH, or any value within the above range.

[0054] According to specific embodiments of the present invention, the time of the freezing treatment is not particularly limited, and those skilled in the art can select according to the situation. As some specific examples, the time of the freezing treatment is 0.5 to 3 h, such as 0.5 h, 0.6 h, 0.8 h, 1 h, 1.2 h, 1.5 h, 2 h, 2.5 h, 2.8 h, 3 h, or any value within the above range.

[0055] (3) After drying the micro-ice crystal electrode, it is wound with a separator into an intermediate of a supercapacitor core package, and the intermediate of the supercapacitor core package is fixed by an elastic member to obtain the supercapacitor core package.

[0056] This step can buffer the radial extrusion force on the tail separator during the liquid injection process of the supercapacitor due to the swelling of the electrode by liquid absorption and during the charging process of the supercapacitor product due to the swelling of the electrode by adsorbing electrolyte ions, fundamentally avoiding the problem of rupture or damage of the tail separator of the supercapacitor core package, and greatly improving the qualification rate of supercapacitor assembly and product performance.

[0057] According to a specific embodiment of the present invention, the manner of the drying treatment is not particularly limited, and those skilled in the art can select according to the situation. As some specific examples, the manner of the drying treatment includes heat drying; the temperature of the drying treatment is not particularly limited, and those skilled in the art can select according to the situation. As some specific examples, the temperature of the drying treatment is 80-140 °C, such as 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C or any value within the above range.

[0058] According to a specific embodiment of the present invention, the time of the drying treatment is not particularly limited, and those skilled in the art can select according to the situation. The time of the drying treatment is 1-5 h, such as 1 h, 2 h, 3 h, 4 h, 5 h or any value within the above range.

[0059] According to a specific embodiment of the present invention, the dried micro-ice crystal electrode can be cut as needed, with half used as the positive electrode and the other half used as the negative electrode, and then wound with the separator.

[0060] According to a specific embodiment of the present invention, the separator is a cellulose separator.

[0061] According to a specific embodiment of the present invention, the thickness of the separator is not particularly limited, and those skilled in the art can select according to the situation. The thickness of the separator is 10-50 μm, such as 10 μm, 20 μm, 30 μm, 40 μm, 50 μm or any value within the above range.

[0062] According to a specific embodiment of the present invention, the type of the elastic member is not particularly limited, as long as the adjustable elastic tension and controllable elastic strain can be achieved. As some specific examples, the elastic member can be a rubber sleeve, a rubber band, etc.

[0063] According to a specific embodiment of the present invention, the tension strength of the elastic member can be 10-40 N, such as 10 N, 20 N, 30 N, 40 N or any value within the above range.

[0064] According to specific embodiments of the present invention, the elastic coefficient of the elastic member can be 0.1 to 2 N / mm, such as 0.1 N / mm, 0.5 N / mm, 1 N / mm, 2 N / mm, or any value within the above range.

[0065] According to specific embodiments of the present invention, the elastic member can be a rubber sleeve. The diameter of the rubber sleeve can be 19 to 56 mm, the height can be 10 to 50 mm, the tensile strength can be 10 to 40 N, and the elastic coefficient can be 0.2 to 2 N / mm.

[0066] According to specific embodiments of the present invention, the elastic member can also be a rubber band. The rubber band is a closed ring structure. The diameter of the ring can be 19 to 56 mm, and the cross-sectional area of a single rubber band is 0.5 to 2.25 mm 2 , the tensile strength can be 10 to 40 N, and the elastic coefficient can be 0.1 to 1 N / mm.

[0067] According to specific embodiments of the present invention, the number of the elastic members is 1 to 5; specifically, the number of the elastic members is 1, 2, 3, 4, or 5.

[0068] According to specific embodiments of the present invention, the elastic member is fixed in the middle and / or at both ends of the supercapacitor core package intermediate body.

[0069] According to an embodiment of the present invention, in a second aspect of the present invention, there is provided a supercapacitor core package obtained by the preparation method according to the first aspect.

[0070] Thus, the problem of tail separator breakage and damage can be avoided in this supercapacitor core package, and the qualified rate of supercapacitor assembly and product performance can be improved when used to prepare a supercapacitor.

[0071] In a third aspect of the present invention, there is provided a supercapacitor, which includes the supercapacitor core package obtained by the preparation method according to the first aspect or the supercapacitor core package according to the second aspect.

[0072] Thus, this supercapacitor is not prone to short-circuit failure, and its self-discharge performance, high-temperature durability, and cycle stability are all superior to those of cylindrical supercapacitors assembled by the existing process. It can achieve a self-discharge voltage retention of more than 95% for 24 hours, a high-temperature load performance of not less than 2000 hours, and a cycle life of more than one million times.

[0073] According to specific embodiments of the present invention, the specifications of the supercapacitor are not particularly limited and can be cylindrical supercapacitors. Their diameter and height can be selected according to circumstances. As some specific examples, the diameter can be 22 - 60 mm, such as 22 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, or any value within the above range, and the height can be 45 - 138 mm, such as 45 mm, 50 mm, 55 mm, 60 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, 85 mm, 90 mm, 95 mm, 100 mm, 105 mm, 110 mm, 115 mm, 120 mm, 125 mm, 130 mm, 138 mm, or any value within the above range.

[0074] The solution of the present invention will be explained below in conjunction with embodiments. Those skilled in the art will understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. For those without specific techniques or conditions noted in the embodiments, the techniques or conditions described in the literature in the art or according to the product specifications are followed. For reagents or instruments without the manufacturer noted, they are all conventional products that can be obtained through commercial purchase.

[0075] Example 1

[0076] (1) Take a rolled activated carbon electrode with a thickness of 200 μm after rolling and place it in an environment of 65 °C and 95% RH for 2 h to obtain a moisture-absorbing electrode with a moisture content of 28.5%.

[0077] (2) Transfer the moisture-absorbing electrode obtained in step (1) to an environment of -20 °C and 20% RH for freeze treatment for 1 h to cause the moisture in the moisture-absorbing electrode to form micro ice crystals and expand to an equilibrium state, obtaining a micro ice crystal electrode with a thickness of 207 μm.

[0078] (3) Transfer the micro ice crystal electrode obtained in step (2) to a blast drying oven and dry it at 100 °C for 2 h. After the dried electrode is slit, it is wound with a cellulose separator with a thickness of 30 μm into an intermediate of a cylindrical supercapacitor core package of Ф22 mm × 45 mm. Use a rubber sleeve with a diameter of 19 mm, a height of 10 mm, a tensile strength of 25 N, and an elastic coefficient of 0.5 N / mm to fix the middle of the core package intermediate to obtain a cylindrical supercapacitor core package of Ф22 mm × 45 mm.

[0079] (4) Subject the cylindrical supercapacitor core package obtained in step (3) to drying, casing, liquid injection, sealing, and aging processes to obtain a cylindrical supercapacitor of Ф22 mm × 45 mm.

[0080] Example 2

[0081] (1) Take the rolled activated carbon electrode with a thickness of 200 μm after roll pressing and place it in an environment of 70 °C and 95% RH for 2 h to obtain a moisture-absorbing electrode with a water content of 28.3%;

[0082] (2) Transfer the moisture-absorbing electrode obtained in step (1) to an environment of -20 °C and 20% RH for freeze treatment for 1 h, so that the water in the moisture-absorbing electrode forms micro ice crystals and expands to an equilibrium state to obtain a micro ice crystal electrode with a thickness of 207 μm;

[0083] (3) Transfer the micro ice crystal electrode obtained in step (2) to a blast drying oven and dry it at 100 °C for 2 h. After the dried electrode is slit, it is wound with a cellulose separator with a thickness of 30 μm into a cylindrical supercapacitor core package intermediate of Ф35 mm × 63 mm. Use a rubber sleeve with a diameter of 31 mm, a height of 15 mm, a tensile strength of 35 N, and an elastic coefficient of 0.75 N / mm to fix the middle of the core package intermediate to obtain a Ф35 mm × 63 mm cylindrical supercapacitor core package;

[0084] (4) Obtain a Ф35 mm × 63 mm cylindrical supercapacitor through the processes of drying, casing, injecting electrolyte, sealing, and aging for the cylindrical supercapacitor core package obtained in step (3).

[0085] Example 3

[0086] (1) Take the rolled activated carbon electrode with a thickness of 200 μm after roll pressing and place it in an environment of 75 °C and 96% RH for 2 h to obtain a moisture-absorbing electrode with a water content of 28.6%;

[0087] (2) Transfer the moisture-absorbing electrode obtained in step (1) to an environment of -20 °C and 20% RH for freeze treatment for 1 h, so that the water in the moisture-absorbing electrode forms micro ice crystals and expands to an equilibrium state to obtain a micro ice crystal electrode with a thickness of 207 μm;

[0088] (3) Transfer the micro ice crystal electrode obtained in step (2) to a blast drying oven and dry it at 100 °C for 2 h. After the dried electrode is slit, it is wound with a cellulose separator with a thickness of 30 μm into a cylindrical supercapacitor core package intermediate of Ф35 mm × 83 mm. Use a rubber sleeve with a diameter of 31 mm, a height of 20 mm, a tensile strength of 40 N, and an elastic coefficient of 1 N / mm to fix the middle of the core package intermediate to obtain a Ф35 mm × 83 mm cylindrical supercapacitor core package;

[0089] (4) Obtain a Ф35 mm × 83 mm cylindrical supercapacitor through the processes of drying, casing, injecting electrolyte, sealing, and aging for the cylindrical supercapacitor core package obtained in step (3).

[0090] Example 4

[0091] (1) Take the rolled activated carbon electrode with a thickness of 200 μm after rolling and place it in an environment of 69 °C and 98% RH for 2 h to obtain a moisture-absorbing electrode with a moisture content of 28.6%;

[0092] (2) Transfer the moisture-absorbing electrode obtained in step (1) to an environment of -20 °C and 20% RH for freeze treatment for 1 h, so that the moisture in the moisture-absorbing electrode forms micro ice crystals and expands to an equilibrium state to obtain a micro ice crystal electrode with a thickness of 207 μm;

[0093] (3) Transfer the micro ice crystal electrode obtained in step (2) to a blast drying oven and dry it at 100 °C for 2 h. After the dried electrode is slit, it is wound with a cellulose separator with a thickness of 30 μm into a cylindrical supercapacitor core package intermediate of Ф60 mm × 138 mm. The two ends of the core package intermediate are fixed with two rubber sleeves with a diameter of 55 mm, a height of 40 mm, a tensile strength of 40 N, and an elastic coefficient of 2 N / mm to obtain a cylindrical supercapacitor core package of Ф60 mm × 138 mm;

[0094] (4) The cylindrical supercapacitor core package obtained in step (3) is subjected to drying, casing, liquid injection, sealing, and aging processes to obtain a cylindrical supercapacitor of Ф60 mm × 138 mm.

[0095] Comparative Example 1

[0096] (1) Take the rolled activated carbon electrode with a thickness of 200 μm after rolling, slit it, and wind it with a cellulose separator with a thickness of 30 μm into a cylindrical supercapacitor core package intermediate of Ф22 mm × 45 mm. The tail separator of the core package intermediate is fixed with a high-temperature tape with a width of 10 mm to obtain a cylindrical supercapacitor core package of Ф22 mm × 45 mm;

[0097] (2) The cylindrical supercapacitor core package obtained in step (1) is subjected to drying, casing, liquid injection, sealing, and aging processes to obtain a cylindrical supercapacitor of Ф22 mm × 45 mm.

[0098] Comparative Example 2

[0099] (1) Take the rolled activated carbon electrode with a thickness of 200 μm after rolling, slit it, and wind it with a cellulose separator with a thickness of 30 μm into a cylindrical supercapacitor core package intermediate of Ф22 mm × 45 mm. The tail separator is pasted and fixed at the end of the core package intermediate by spraying with a high-temperature resistant glue to obtain a cylindrical supercapacitor core package of Ф22 mm × 45 mm;

[0100] (2) The cylindrical supercapacitor core package obtained in step (1) is subjected to drying, casing, liquid injection, sealing, and aging processes to obtain a cylindrical supercapacitor of Ф22 mm × 45 mm.

[0101] Comparative Example 3

[0102] (1) Take the rolled activated carbon electrode with a thickness of 200 μm after roll pressing, cut it into pieces, and wind it with a cellulose separator with a thickness of 30 μm into a cylindrical supercapacitor core package intermediate of Ф22 mm × 45 mm. Fix the core package intermediate with a rubber sleeve with a diameter of 19 mm, a height of 10 mm, a tensile strength of 25 N, and an elastic modulus of 0.5 N / mm to obtain a cylindrical supercapacitor core package of Ф22 mm × 45 mm;

[0103] (2) Subject the cylindrical supercapacitor core package obtained in step (1) to drying, casing, liquid injection, sealing, and aging processes to obtain a cylindrical supercapacitor of Ф22 mm × 45 mm.

[0104] Comparative Example 4

[0105] (1) Place the rolled activated carbon electrode with a thickness of 200 μm after roll pressing in an environment of 65 °C and 95% RH for 2 h to obtain a moisture-absorbing electrode with a moisture content of 28.5%;

[0106] (2) Transfer the moisture-absorbing electrode obtained in step (1) to an environment of -20 °C and 20% RH for freeze treatment for 1 h, so that the moisture in the moisture-absorbing electrode forms micro ice crystals and expands to an equilibrium state to obtain a micro ice crystal electrode with a thickness of 207 μm;

[0107] (3) Transfer the micro ice crystal electrode obtained in step (2) to a blast drying oven and dry it at 100 °C for 2 h. After cutting the dried electrode, wind it with a cellulose separator with a thickness of 30 μm into a cylindrical supercapacitor core package intermediate of Ф22 mm × 45 mm. Fix the tail separator of the core package intermediate with a high-temperature tape with a width of 10 mm to obtain a cylindrical supercapacitor core package of Ф22 mm × 45 mm;

[0108] (4) Subject the cylindrical supercapacitor core package obtained in step (3) to drying, casing, liquid injection, sealing, and aging processes to obtain a cylindrical supercapacitor of Ф22 mm × 45 mm.

[0109] Test Example

[0110] Electrical performance test of supercapacitor:

[0111] Capacity and ESR: Charge the cylindrical supercapacitors obtained in Examples 1-4 and Comparative Examples 1-4 to 2.7 V, and test the capacity and ESR of the supercapacitors according to the Maxwell six-step method.

[0112] ΔV SD Test of / V: First, charge the cylindrical supercapacitors obtained in Examples 1-4 and Comparative Examples 1-4 to 2.7 V and perform constant voltage charging for 12 h. After standing for 24 h, use a multimeter to test the residual voltage V0 of the supercapacitor, and calculate the self-discharge voltage retention rate of the supercapacitor according to the formula (V - V0) / V.

[0113] Tail diaphragm state: First, the cylindrical supercapacitors obtained in Examples 1-4 and Comparative Examples 1-4 were respectively subjected to constant voltage power-on at 2.7V for 1000h / 2000h at 65°C or cyclic charge and discharge 500,000 times / 1,000,000 times at room temperature within the range of 0-2.7V. Then, the supercapacitors were discharged to below 0.1V and the product was disassembled to observe the tail diaphragm of the core package.

[0114] The cylindrical supercapacitors obtained in each example and comparative example were subjected to electrical performance tests, and the results are shown in Table 1.

[0115] Table 1

[0116]

[0117] From the test results in Table 1, it can be seen that the capacitance and internal resistance of the cylindrical supercapacitors assembled according to the solution of the present invention meet the industry standards, the self-discharge voltage after 24h remains above 95%, and there is no fracture or damage to the tail diaphragm of the product after 2000h of high-temperature load at 2.7V and 65°C or 1,000,000 times of cyclic charge and discharge in the range of 0-2.7V. Among them, Comparative Examples 1 and 2 adopted the traditional assembly process, and the self-discharge voltage of the obtained cylindrical supercapacitors after 24h remained at 93.8%. After 1000h of high-temperature load at 2.7V and 65°C or 500,000 times of cyclic charge and discharge in the range of 0-2.7V, the tail diaphragm of the product broke. Continuing the high-temperature load would cause the fracture surface to expand, resulting in direct contact between the positive and negative electrodes of the supercapacitor and short-circuit failure. In Comparative Example 3, only a rubber sleeve was used to fix the core package intermediate to assemble the supercapacitor product. The self-discharge voltage of the obtained cylindrical supercapacitors after 24h remained below 95%. After 2000h of high-temperature load at 2.7V and 65°C or 1,000,000 times of cyclic charge and discharge in the range of 0-2.7V, there was a tendency for the tail diaphragm to break. This was because the activated carbon electrode used in Comparative Example 3 was not subjected to moisture absorption and freezing treatment. Therefore, during the process of injecting liquid into the supercapacitor core package and during the long-term high-temperature load or long-term cyclic charge and discharge test of the supercapacitor, the electrode thickness would increase significantly, thereby exerting a large radial extrusion pressure on the tail diaphragm of the core package. In Comparative Example 4, the activated carbon electrode after moisture absorption treatment and freezing treatment and drying treatment was used to assemble the supercapacitor product. The self-discharge voltage of the obtained cylindrical supercapacitors after 24h remained at 95%. After 2000h of high-temperature load at 2.7V and 65°C or 1,000,000 times of cyclic charge and discharge in the range of 0-2.7V, the tail diaphragm of the product broke. This was because in Comparative Example 4, the traditional process was used to fix the tail diaphragm of the core package intermediate, so that the increase in electrode thickness during the long-term high-temperature load or long-term cyclic charge and discharge test of the supercapacitor could not be released, thereby continuously exerting a radial extrusion pressure on the tail diaphragm of the core package.

[0118] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0119] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A preparation method of a supercapacitor core package, characterized in that, Comprising: Preparing a moisture-absorbing electrode with a water content of 20% to 30%; Freezing the moisture-absorbing electrode to obtain a micro-ice crystal electrode; After drying the micro-ice crystal electrode, winding it with a separator into an intermediate of a supercapacitor core package, and fixing the intermediate of the supercapacitor core package through an elastic member to obtain the supercapacitor core package.

2. The preparation method according to claim 1, wherein The preparation of the moisture-absorbing electrode with a water content of 20% to 30% includes: placing the roll-pressed electrode in an environment with a humidity of 80 to 99% RH to absorb moisture until the water content is 20% to 30% to obtain the moisture-absorbing electrode with a water content of 20% to 30%; Or, placing the roll-pressed electrode in an environment with a temperature of 50 to 90 °C and a humidity of 80 to 99% RH to absorb moisture until the water content is 20% to 30% to obtain the moisture-absorbing electrode with a water content of 20% to 30%; Optionally, the thickness of the roll-pressed electrode is 100 to 300 μm; Optionally, in the method for preparing the moisture-absorbing electrode with a water content of 20% to 30%, the moisture absorption time is 1 to 5 h.

3. The preparation method according to claim 1, characterized in that, The temperature of the freezing treatment is -40 to -5 °C; Optionally, the humidity of the freezing treatment is 10 to 40% RH; Optionally, the time of the freezing treatment is 0.5 to 3 h; Optionally, the drying treatment method includes heat drying.

4. The preparation method according to claim 1, wherein, The temperature of the drying treatment is 80 to 140 °C.

5. The preparation method according to claim 1, characterized in that, The time of the drying treatment is 1 to 5 h.

6. The preparation method according to claim 1, wherein, The tensile strength of the elastic member is 10 to 40 N.

7. The preparation method according to claim 1, characterized in that, The elastic coefficient of the elastic member is 0.1 to 2 N / mm.

8. The preparation method according to claim 1, characterized in that, The number of the elastic members is 1 to 5; and / or, The elastic member is fixed at the middle and / or both ends of the intermediate of the supercapacitor core package.

9. A supercapacitor core package obtained by the preparation method according to any one of claims 1 to 8.

10. A supercapacitor, characterized in that, Comprising a supercapacitor core package obtained by the preparation method according to any one of claims 1 to 8 or the supercapacitor core package according to claim 8.

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