A high energy density capacitor

Abstract

The utility model discloses a kind of high-energy-density capacitors, belong to capacitor technical field.The device includes shell, the shell one end is provided with positive pole, the other end is provided with negative pole, the shell inside is provided with the positive pole carrying sheet and negative pole carrying sheet treated by in-situ growth three-dimensional carbon network, the positive pole carrying sheet is fixedly provided with positive pole lug, the positive pole lug is electrically connected with shell positive pole, the negative pole carrying sheet is fixedly provided with negative pole lug, the negative pole lug is electrically connected with shell negative pole, the positive pole carrying sheet and negative pole carrying sheet between are provided with dielectric film.The utility model cooperates with flexible electrode when using, charge storage mechanism is significantly optimized by three-dimensional carbon network, the high specific surface area characteristics of three-dimensional carbon network provides abundant site for ion adsorption, in combination with the nano-pore structure of dielectric film, high-density electric layer is formed on electrode surface, and unit volume charge storage amount is greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of capacitor technology, and in particular to a high energy density capacitor. Background Technology

[0002] A capacitor is a passive electronic component that stores electrical charge and energy. Its core consists of two insulated conductive plates (such as metal foil) and a dielectric material (such as ceramic, polymer film, or electrolyte) sandwiched between them. When a voltage is applied to the plates, positive and negative charges accumulate on the surfaces of the plates, forming an electrostatic field and storing electrical energy. When the voltage is removed, the charges are slowly released, thus realizing the function of storing and releasing electrical energy.

[0003] High-energy-density capacitors are energy storage devices that combine high energy storage with rapid charging and discharging capabilities. Their core lies in using aluminum foil as a motor, combined with ionic liquids or gel electrolytes to increase the operating voltage to 3-4V, thus increasing the energy density by 10-100 times compared to traditional capacitors.

[0004] The shortcomings of the above-mentioned existing technical solutions are that when aluminum foil is used as an electrode, its surface is relatively flat. This structural characteristic will significantly limit the number of effective sites for charge adsorption, thereby "locking" the specific surface area of ​​the aluminum foil electrode at a low level, which becomes the core bottleneck restricting its energy density breakthrough. Utility Model Content

[0005] This invention provides a high energy density capacitor that can solve the problem in the prior art where the surface of aluminum foil as an electrode is relatively flat, thus limiting the number of effective charge adsorption sites.

[0006] A high energy density capacitor includes a casing, with a positive electrode at one end and a negative electrode at the other end. Inside the casing are a positive electrode support plate and a negative electrode support plate, both treated with an in-situ grown three-dimensional carbon network. A positive electrode tab is fixedly disposed on the positive electrode support plate and electrically connected to the positive electrode of the casing. A negative electrode tab is fixedly disposed on the negative electrode support plate and electrically connected to the negative electrode of the casing. A dielectric film is disposed between the positive and negative electrode support plates, and an electrolyte is filled between them.

[0007] As a further embodiment of this invention: both the positive electrode support sheet and the negative electrode support sheet are metallized polyimide films.

[0008] As a further embodiment of this utility model: the positive electrode support sheet and the negative electrode support sheet are intertwined to form a roll.

[0009] As a further embodiment of this invention, the positive electrode tab is provided in multiple sets.

[0010] As a further embodiment of this utility model, the negative electrode tab is provided in multiple sets.

[0011] As a further embodiment of this invention, the dielectric film is a polypropylene diaphragm.

[0012] As a further embodiment of this invention, the electrolyte filled between the positive electrode support sheet and the negative electrode support sheet is a gel polymer electrolyte.

[0013] As a further embodiment of this utility model: a polyimide film is wound around the outside of the roll body formed by the intertwining of the positive electrode support sheet and the negative electrode support sheet.

[0014] As a further aspect of this invention, the interior of the outer shell is designed to be a vacuum.

[0015] As a further embodiment of this utility model, the height and length of the positive electrode support sheet and the negative electrode support sheet are the same.

[0016] The beneficial effects of this utility model are:

[0017] 1. In use, this invention significantly optimizes the charge storage mechanism through the synergistic design of a three-dimensional carbon network and a flexible electrode. The high specific surface area of ​​the three-dimensional carbon network provides abundant sites for ion adsorption, and combined with the nanoporous structure of the dielectric film, a high-density electric layer is formed on the electrode surface, greatly increasing the charge storage capacity per unit volume.

[0018] 2. When this utility model is used, during the charging and discharging process, the three-dimensional carbon network can not only buffer the volume stress caused by ion insertion / extraction, but also avoid the pulverization failure caused by mechanical deformation of traditional electrodes, thus extending the service life and meeting the stringent requirements of high reliability scenarios. Attached Figure Description

[0019] Figure 1 A schematic diagram of the overall structure of a high energy density capacitor provided by this utility model;

[0020] Figure 2 This utility model provides a front view of a high energy density capacitor after disassembly.

[0021] Figure 3 This is a schematic diagram of the rear view of a high energy density capacitor after disassembly, as provided by this utility model.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. Outer shell; 2. Positive electrode carrier plate; 201. Positive electrode tab; 3. Negative electrode carrier plate; 301. Negative electrode tab; 4. Dielectric film. Detailed Implementation

[0024] The specific embodiments of this utility model are described in detail below, but it should be understood that the protection scope of this utility model is not limited to the specific embodiments.

[0025] like Figures 1 to 3 As shown in the figure, the high energy density capacitor provided by this utility model includes a shell 1. Inside the shell 1, a positive electrode carrier sheet 2 and a negative electrode carrier sheet 3 are integrated by an automated winding device. Both sets of carrier sheets have undergone in-situ growth of three-dimensional carbon network modification treatment. The specific process adopts plasma-enhanced chemical vapor deposition technology to generate a carbon nanofiber network with high specific surface area on the surface of a flexible polymer substrate by pyrolysis, forming a three-dimensional porous structure with both electron conduction channels and ion adsorption sites.

[0026] Multiple sets of positive electrode tabs 201 are provided on the surface of the positive electrode support sheet 2. These tabs are formed with the electrode body using a highly conductive composite material, achieving a metallurgical-grade connection with significantly higher conductivity than traditional foil tab structures. A corresponding number of negative electrode tabs 301 are simultaneously provided on the negative electrode support sheet 3. Both are connected to the positive and negative terminals of the outer shell 1 via a metal welding process, forming a low-impedance ohmic contact and constructing a distributed current collection network. This multi-tab parallel design significantly reduces the equivalent series resistance of the capacitor, improves high-frequency pulse charge-discharge performance, and maintains high power transmission efficiency even under extreme temperature conditions. A dielectric film 4 is sandwiched between the positive and negative electrode support sheets 3. This film is prepared using a biaxial stretching process, exhibiting high porosity and nanoscale pore size distribution. An inorganic nano-coating is applied to its surface to enhance thermal stability and ion selectivity, maintaining high ion penetration capability even at low temperatures.

[0027] The electrolyte system employs a gel polymer electrolyte, which is filled into the electrode gaps through in-situ polymerization. This electrolyte uses a high-dielectric-constant organic solvent as a plasticizer, combined with a highly soluble lithium salt to form a three-dimensional ion-conducting network. It possesses both high ionic conductivity and mechanical flexibility, buffering volumetric stress during charging and discharging to prevent electrode pulverization. During charging, external power drives electrons through the positive electrode of the outer casing 1 and multiple sets of positive electrode tabs 201 into the positive electrode support sheet 2, causing lithium ions in the electrolyte to embed into the pores of the three-dimensional carbon network. Simultaneously, anions are adsorbed onto the positive electrode surface under electrostatic attraction, forming a high-density electric double layer on both sides of the dielectric film 4. During discharging, the stored chemical energy is released through ion reverse migration and electrons via the negative electrode tabs 301 and the negative electrode of the outer casing 1. The entire charging and discharging process is completed in a very short time, resulting in high energy conversion efficiency and extremely low capacity decay during long-term cycling.

[0028] To improve space utilization and energy density, the positive and negative electrode carrier plates 3 employ a variable-diameter spiral winding process, maximizing the effective electrode area within the limited space of the outer shell 1. The winding body is wrapped with multiple layers of high-temperature resistant insulating tape, preferably polyimide film, and incorporates highly thermally conductive inorganic fillers through a molecular-level blending process. This provides both electrolyte wetting buffering and thermal management functions, significantly reducing the capacitor's operating temperature rise and maintaining structural integrity in high-temperature environments. The interior of the outer shell 1 is thoroughly evacuated using a vacuum molecular pump process to remove residual gas and moisture, combined with laser welding sealing technology. This significantly reduces the capacitor's annual self-discharge rate and maintains a high capacity retention rate even in extreme high-temperature and high-humidity environments, meeting the stringent energy density, power density, and environmental adaptability requirements of existing devices. Its energy density is several times higher than that of traditional aluminum electrolytic capacitors, and its power density breaks through the technological threshold of traditional devices, providing a key technological path for the development of next-generation high-power energy storage devices.

[0029] To facilitate understanding by those skilled in the art, the in-situ growth process of the three-dimensional carbon network on the positive electrode support 2 and the negative electrode support 3 includes: selecting metallized polyimide (PI) as a conductive flexible support for direct use as a current collector; and performing catalytic treatment on the surface of the support, such as depositing transition metal nanoparticles like iron (Fe) and cobalt (Co).

[0030] The catalytically treated substrate is placed in a CVD reaction chamber, and hydrocarbon gas is introduced as the carbon source. The reaction temperature, gas flow rate, and reaction time are controlled to decompose the carbon source on the catalyst surface and grow a three-dimensional carbon nanotube array or graphene network. The morphology and conductivity of the three-dimensional carbon network are then optimized by adjusting CVD process parameters, such as gas ratio, reaction time, and temperature gradient. For example, growing a vertically aligned carbon nanotube array can improve the conductivity and mechanical stability of the electrode. The treated substrate uses the in-situ grown three-dimensional carbon network directly as the electrode material, eliminating the need for an additional coating step.

[0031] The above-described in-situ growth of three-dimensional carbon network processing steps are existing technologies and are for reference only for those skilled in the art.

[0032] Working Principle: When an external power source is connected to the capacitor, the energy storage system consisting of the positive electrode support plate 2 and the negative electrode support plate 3 begins to operate. Driven by an electric field, electrons from the external circuit are rapidly injected into the positive electrode support plate 2 from the positive terminal through multiple sets of positive electrode tabs 201. Thanks to the three-dimensional carbon network structure grown in situ on the surface of the positive electrode support plate 2, its high conductivity and high specific surface area allow electrons to rapidly diffuse throughout the entire electrode area. At the same time, lithium ions in the electrolyte migrate to the surface of the negative electrode support plate 3 under the action of the electric field, while anions accumulate on the surface of the positive electrode support plate 2 due to electrostatic adsorption. The porous structure of the three-dimensional carbon network provides abundant adsorption sites for ions, forming a high-density double-layer structure together with the dielectric film 4. In this double-layer, positive and negative charges are closely arranged, efficiently storing electrical energy in the form of electric field energy. During this process, the gel polymer electrolyte, with its high ionic conductivity and flexible properties, ensures rapid ion conduction within the electrode gap, while buffering the volume stress during charging and discharging, maintaining the stability of the electrode structure.

[0033] When the external circuit is closed, the capacitor enters the discharge state. At this time, electrons adsorbed on the surface of the positive electrode support plate 2 form a current loop with the positive electrode of the outer casing 1 through multiple sets of positive electrode tabs 201, releasing electrical energy through the external load. Simultaneously, anions on the surface of the positive electrode support plate 2 begin to desorb due to charge balance requirements, while lithium ions embedded on the surface of the negative electrode support plate 3 migrate in the opposite direction under the drive of the electric field, passing through the nanopores of the dielectric film 4 and the three-dimensional ion channels of the gel polymer electrolyte, and re-entering the electrolyte system. This synergistic effect of ion migration and electron flow enables the capacitor to complete energy release and restore its electrically neutral state in a very short time. Due to the synergistic effect of the high specific surface area electrode and the high ionic conductivity electrolyte, the capacitor can maintain high power density output during discharge, and its energy conversion efficiency is significantly better than that of traditional aluminum electrolytic capacitors.

[0034] The above-disclosed embodiments are only a few specific examples of the present utility model. However, the embodiments of the present utility model are not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the protection scope of the present utility model.

Claims

1. A high energy density capacitor, comprising a housing (1), wherein a positive electrode is disposed at one end of the housing (1) and a negative electrode is disposed at the other end, characterized in that, The outer shell (1) is provided with a positive electrode support plate (2) and a negative electrode support plate (3) that have been treated by in-situ growth of a three-dimensional carbon network. A positive electrode tab (201) is fixedly disposed on the positive electrode support plate (2) and the positive electrode tab (201) is electrically connected to the positive electrode of the outer shell (1). A negative electrode tab (301) is fixedly disposed on the negative electrode support plate (3) and the negative electrode tab (301) is electrically connected to the negative electrode of the outer shell (1). A dielectric film (4) is disposed between the positive electrode support plate (2) and the negative electrode support plate (3). An electrolyte is filled between the positive electrode support plate (2) and the negative electrode support plate (3).

2. A high energy density capacitor as described in claim 1, characterized in that, Both the positive electrode support sheet (2) and the negative electrode support sheet (3) are metallized polyimide films.

3. A high energy density capacitor as described in claim 2, characterized in that, The positive electrode support sheet (2) and the negative electrode support sheet (3) are intertwined to form a roll.

4. A high energy density capacitor as described in claim 1, characterized in that, The positive electrode tab (201) is provided in multiple sets.

5. A high energy density capacitor as described in claim 4, characterized in that, The negative electrode tab (301) is provided in multiple sets.

6. A high energy density capacitor as described in claim 3 or 5, characterized in that, The dielectric film (4) is a polypropylene diaphragm.

7. A high energy density capacitor as described in claim 3, characterized in that, The electrolyte filled between the positive electrode support sheet (2) and the negative electrode support sheet (3) is a gel polymer electrolyte.

8. A high energy density capacitor as described in claim 7, characterized in that, The outer side of the roll body formed by the intertwining of the positive electrode support sheet (2) and the negative electrode support sheet (3) is wrapped with a polyimide film.

9. A high energy density capacitor as described in claim 1, characterized in that, The interior of the outer shell (1) is set in a vacuum.

10. A high energy density capacitor as described in claim 1, characterized in that, The positive electrode support plate (2) and the negative electrode support plate (3) have the same height and length.

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