Super capacitor energy storage system with high energy density

Abstract

The invention relates to the technical field of capacitor energy storage, and particularly discloses a super capacitor energy storage system with high energy density, which comprises a super capacitor, the super capacitor adopts a double-layer capacitor and pseudocapacitor composite energy storage mechanism, and an electrode material of the super capacitor is switched between a double-layer capacitor reaction and a pseudocapacitor reaction; the charging and discharging control module is used for adjusting the current and the voltage of the super capacitor through the embedded controller and carrying out energy management; the energy management is combined with an MPPT algorithm and a DPC algorithm to carry out charging and discharging management; and the heat dissipation module is used for carrying out heat dissipation on the super capacitor. According to the system, by adopting a double-layer capacitor and pseudocapacitor composite energy storage mechanism, the energy storage and release performance of the supercapacitor is remarkably improved, intelligent management of charging and discharging of the supercapacitor is achieved by combining MPPT and DPC algorithms, and the energy conversion efficiency is improved; the heat dissipation module prevents the super capacitor from being overheated due to high-power discharge, and guarantees long-term stable operation of the system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of capacitor energy storage, and particularly relates to a supercapacitor energy storage system with high energy density. BACKGROUND

[0002] With the transformation of global energy structure, the demand for green energy and efficient energy storage technology is increasing. Supercapacitors have been widely used in electric vehicles, renewable energy storage, public transportation, power systems and other fields due to their high power density, long life and fast charging and discharging characteristics.

[0003] At present, the existing supercapacitors have certain limitations in energy density, and the balance between capacity and power has not reached the ideal state. At the same time, supercapacitors are prone to overheating during high-power discharge, which affects their performance and life, which limits the application of supercapacitors in a wider field. In the prior art, some supercapacitors improve performance by optimizing electrode materials and electrolytes, but most of them focus on a single energy storage mechanism and fail to effectively combine the advantages of both. Although some technologies use multi-layer electrode structures and high-efficiency heat dissipation modules, the design of multi-layer electrodes and heat dissipation systems and the fine adjustment of charging and discharging control have not been completely optimized, especially in high-power applications. The comprehensive optimization of system stability, heat dissipation efficiency and energy management is still a challenge. In addition, the existing charging and discharging control technology often relies on simple current and voltage regulation, lacks intelligent adjustment capability for different use scenarios, and cannot fully optimize the charging and discharging efficiency of supercapacitors, affecting the overall energy efficiency and stability of the system. SUMMARY

[0004] The purpose of the present application is to provide a supercapacitor energy storage system with high energy density to solve the problems of low energy density, unintelligent charging and discharging management, and inability to maximize the optimization of charging and discharging efficiency and overall system performance.

[0005] To achieve the above-mentioned purpose, the technical solution provided by the present application is:

[0006] A supercapacitor energy storage system with high energy density, characterized in that it comprises:

[0007] A supercapacitor, which adopts a double-layer capacitor and pseudo-capacitor composite energy storage mechanism, and the electrode material of the supercapacitor switches between double-layer capacitor reaction and pseudo-capacitor reaction.

[0008] A charging and discharging control module for adjusting the current and voltage of the supercapacitor through an embedded controller to manage energy; the energy management combines MPPT algorithm and DPC algorithm for charging and discharging management.

[0009] A heat dissipation module for dissipating heat for the supercapacitor.

[0010] To optimize the above technical solutions, the specific measures / limitations taken also include:

[0011] The electrode material of the supercapacitor is selected from carbon-based materials, metal oxides, conductive polymers, or composites thereof, and the electrolyte of the supercapacitor is selected from liquid electrolytes, solid electrolytes, or gel electrolytes.

[0012] The synergistic reaction of double-layer capacitance and pseudo-capacitance on the surface of the electrode material of the supercapacitor includes: increasing the specific surface area of the electrode surface of the double-layer by surface modification, enhancing the active sites of the pseudo-capacitance reaction, selecting suitable electrolyte and voltage range, and optimizing the charge and discharge rate to make the double-layer capacitance and pseudo-capacitance work synergistically.

[0013] The specific surface area of the electrode material of the supercapacitor is not less than 1500 m 2 / g, and the conductivity is better than 100 S / cm; the electrolyte is stable in the temperature range of -30-70℃, and the ionic conductivity is not less than 10-2 S / cm.

[0014] The surface of the electrode material of the supercapacitor is modified by nitrogen doping, and the method is as follows: using atmospheric nitriding method, the electrode material and nitrogen source are put into a high temperature furnace together, and heat treatment is carried out in nitrogen or ammonia atmosphere, the temperature is 600-1000℃, and the treatment time is 1-5 hours; or using liquid phase nitriding method: the electrode material is soaked in a solution containing nitrogen source, the temperature is 300-600℃, so that the nitrogen source penetrates into the surface of the electrode material and is doped therein.

[0015] The ionic conductivity of the electrolyte of the supercapacitor is optimized using Nernst equation, and the best electrolyte composition is selected, and the formula is as follows:

[0016]

[0017] In the formula, E is the electromotive force of the supercapacitor, E° is the standard electromotive force, R is the gas constant, T is the temperature, m is the number of electron transfer, F is the Faraday constant, and Q is the reaction quotient.

[0018] It also includes an integrated intelligent control system, a plurality of said supercapacitor units are connected in parallel to form a modular system, the integrated intelligent control system is connected with the charge and discharge control module and the heat dissipation module, and the integrated intelligent control system dynamically adjusts the working state of each supercapacitor connected in parallel.

[0019] Further, a voltage equalization algorithm is used to control the voltage consistency between the supercapacitors connected in parallel, and the voltage equalization algorithm is as follows:

[0020]

[0021] In the formula, V target is a target voltage, V1, V2, …, V n is the voltage of each parallel super capacitor, and n is the number of parallel super capacitors.

[0022] The charge and discharge control module adopts an MPPT algorithm combined with a DPC algorithm, in the charge and discharge process, through an embedded controller to automatically adjust the current and voltage, based on real-time data of the working state of the super capacitor, dynamically adjusts the charge and discharge strategy, as follows

[0023] The combination formula of the MPPT algorithm and the DPC algorithm is as follows:

[0024] P total = P mppt + P dc

[0025] In the formula, P total is the total power of the system, P mppt is the maximum power of the super capacitor obtained by the MPPT algorithm, P dc is the battery charge and discharge power obtained by the DPC algorithm.

[0026] The power management decision formula is as follows:

[0027]

[0028] In the formula, P charge is the power required for charging, and P discharge is the power required for discharging.

[0029] The heat dissipation module adopts finite element analysis and thermal network analysis simulation and optimization of system heat dissipation, wherein the heat dissipation efficiency of the system is calculated through the following heat conduction formula, and dynamic adjustment is carried out.

[0030]

[0031] In the formula, S is the heat flow, k is the thermal conductivity, A is the heat dissipation area, ΔT is the temperature difference, and d is the material thickness.

[0032] The beneficial effects of the present application are as follows:

[0033] The system of the application adopts a double-layer capacitor and pseudo-capacitor composite energy storage mechanism, the super capacitor can switch between double-layer capacitor reaction and pseudo-capacitor reaction, and such mechanism significantly improves the energy storage and release performance of the super capacitor; by integrating an efficient charging and discharging control module, combining the MPPT algorithm and the DPC algorithm, intelligent charging and discharging management is realized, the current and voltage are dynamically adjusted under different working conditions, and efficient energy conversion and stable operation of the system are ensured; the system also adopts an efficient heat dissipation module to avoid overheating during high-power discharging, and ensures long-term stable operation of the system; by increasing the surface area of the electrode material and the interface area between the electrode and the electrolyte, the ion transmission efficiency is improved, thereby optimizing the energy storage and release performance; the electrode material is modified by nitrogen doping to significantly increase the specific surface area and active sites of the electrode material, improve the electrochemical performance of the super capacitor, including the energy density and the power density, thereby enhancing the energy storage and release capacity. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 A high-energy-density super capacitor energy storage system framework of the application. DETAILED DESCRIPTION

[0035] The above content of the application will be further described in the form of specific embodiments, but it should not be understood that the scope of the above subject matter of the application is limited to the following examples, and any technology realized based on the above content of the application belongs to the scope of the application.

[0036] The experimental methods used in the following examples are conventional methods, and the reagents, methods and equipment used are conventional reagents, methods and equipment in the technical field, unless otherwise specified.

[0037] As shown in Figure 1 A high-energy-density super capacitor energy storage system, comprising:

[0038] The super capacitor adopts a double-layer capacitor and pseudo-capacitor composite energy storage mechanism, and the electrode material of the super capacitor switches between double-layer capacitor reaction and pseudo-capacitor reaction.

[0039] The charging and discharging control module adjusts the current and voltage of the super capacitor through the embedded controller, performs energy management, dynamically adjusts the charging and discharging power, and ensures efficient energy management; the energy management combines the MPPT algorithm and the DPC algorithm for charging and discharging management, adjusts the current and voltage in real time according to the working state of the capacitor, and optimizes the charging and discharging strategy.

[0040] The heat dissipation module is used for heat dissipation for the super capacitor.

[0041] In some embodiments, the carbon-based material in the electrode material of the supercapacitor is activated carbon, graphene, or carbon nanotubes, the metal oxide or conductive polymer material is cobalt oxide, manganese oxide, or polyaniline, which has excellent electrical conductivity and chemical stability.

[0042] The electrolyte of the supercapacitor is selected from liquid electrolyte, solid electrolyte, or gel electrolyte, preferably 1M ammonium tetrafluoride solution in acetonitrile, or 1M lithium hexafluorophosphate solution in carbonate solvent, which is stable in the temperature range of -30-70℃ and has an ionic conductivity not less than 10-2S / cm.

[0043] The heat dissipation system uses graphene or aluminum composite material combined with liquid cooling or air cooling system, which can efficiently dissipate heat and ensure the temperature control of the capacitor within a reasonable range during high-power discharge.

[0044] The capacitor shell is made of high-temperature resistant and corrosion-resistant materials to ensure the system can still operate normally in harsh working environment.

[0045] In some embodiments, the synergistic reaction of double-layer capacitance and pseudo-capacitance on the surface of the electrode material of the supercapacitor includes: increasing the specific surface area of the electrode surface through surface modification to improve the formation ability of the double-layer and enhance the active sites of the pseudo-capacitance reaction; selecting appropriate electrolyte, whose ion size and concentration directly affect the formation of the double-layer and the efficiency of the pseudo-capacitance reaction; controlling the working voltage range of the electrode material reasonably to make the double-layer and pseudo-capacitance reactions work synergistically within the appropriate voltage range, avoiding excessive voltage leading to instability or unnecessary side reactions; optimizing the charge and discharge rate to ensure that the electrode material can effectively switch between capacitance and pseudo-capacitance reactions to achieve high-energy storage and release; regularly evaluating the stability of the electrode material and its performance degradation in multiple charge and discharge cycles to ensure that the double-layer and pseudo-capacitance reactions can maintain good synergistic effect in long-term use.

[0046] The synergistic effect of the double-layer and pseudo-capacitance reactions formed on the surface of the electrode material is used to improve the energy density and power density of the supercapacitor.

[0047] Increasing the interface area between the electrode material and the electrolyte, or controlling the porosity and surface modification of the electrode material, is used to improve the ion transport efficiency.

[0048] The specific surface area of the electrode material of the supercapacitor is not less than 1500m 2 / g, and the electrical conductivity is better than 100S / cm.

[0049] In some embodiments, the electrode material surface of the supercapacitor is modified by nitrogen doping, by the following method: using an atmosphere nitrogenization method, the electrode material and nitrogen source are placed in a high-temperature furnace, and heat treatment is performed in a nitrogen or ammonia atmosphere, at a temperature of 600-1000°C, for a treatment time of 1-5 hours; during this process, the nitrogen atoms in the nitrogen source react with the carbon atoms on the surface of the carbon-based material to form nitrogen-doped carbon material; or using a liquid-phase nitrogenization method: the electrode material is soaked in a solution containing a nitrogen source, at a temperature of 300-600°C, so that the nitrogen source penetrates the surface of the electrode material and is doped therein; after the nitrogen doping treatment is completed, cooling, cleaning and drying treatment is required, and the electrode material is usually washed with deionized water or an acid solution to remove unreacted nitrogen source residues and byproducts.

[0050] In some embodiments, commonly used nitrogen sources include ammonia, ammonia water, urea, cyanide, etc., which provide nitrogen atoms during the treatment process.

[0051] If urea or other nitrogen sources are used, they can be copolymerized with carbon sources (such as glucose, fructose, etc.) to form precursors with a high specific surface area, which are then further heat-treated to obtain the rudiments of the electrode material.

[0052] The ionic conductivity of the electrolyte of the supercapacitor is optimized using the Nernst equation to select the optimal electrolyte composition, and the formula is as follows:

[0053]

[0054] In the formula, E is the electromotive force of the supercapacitor, E° is the standard electromotive force, R is the gas constant, T is the temperature, m is the number of electron transfers, F is the Faraday constant, and Q is the reaction quotient.

[0055] An integrated intelligent control system is also included, and multiple supercapacitor units are connected in parallel to form a modular system for improving the overall energy storage capacity of the system.

[0056] The integrated intelligent control system connects the charge and discharge control module and the heat dissipation module, and dynamically adjusts the working state of each supercapacitor connected in parallel.

[0057] A voltage equalization algorithm is used to control the voltage consistency between the supercapacitors connected in parallel, and the voltage equalization algorithm is as follows:

[0058]

[0059] In the formula, V target is the target voltage, V1, V2, …, V n are the voltages of each supercapacitor connected in parallel, and n is the number of supercapacitors connected in parallel.

[0060] The charge-discharge control module adopts MPPT algorithm combined with DPC algorithm, in the charge-discharge process, through the embedded controller automatically adjusts the current and voltage, based on the real-time data of the super capacitor working state, dynamically adjusts the charge-discharge strategy, as follows:

[0061] The combination formula of MPPT algorithm and DPC algorithm is as follows:

[0062] P total = P mppt + P dc

[0063] In the formula, P total is the total power of the system, P mppt is the maximum power of the super capacitor obtained by the MPPT algorithm, P dc is the battery charge-discharge power obtained by the DPC algorithm.

[0064] The power management decision formula is as follows:

[0065]

[0066] In the formula, P charge is the power required for charging, P discharge is the power required for discharging.

[0067] The heat dissipation module adopts finite element analysis and thermal network analysis simulation and optimization of system heat dissipation, wherein the heat conduction efficiency of the system is calculated by the following heat conduction formula, and dynamic adjustment is carried out.

[0068]

[0069] In the formula, S is the heat flow, k is the thermal conductivity, A is the heat dissipation area, ΔT is the temperature difference, and d is the material thickness.

[0070] The super capacitor of the application has a low self-discharge rate, and the performance of the super capacitor under different charge-discharge conditions is predicted by the cycle life formula, which is as follows:

[0071]

[0072] In the formula, N is the cycle number, ω is the capacity attenuation coefficient, V max and V min are the maximum and minimum voltages respectively, and ΔV is the voltage change.

[0073] The super capacitor of the application has a low temperature rise during the charge-discharge process, and can work stably at high power density.

[0074] The maximum power density of the system is 300-500W / kg, and the energy density is 15-20Wh / kg.

[0075] In some embodiments, as in the operation of an electric bus, the supercapacitor stores and provides instantaneous high-power electrical energy to support the rapid power requirements of the bus during acceleration, braking, and stopping, specifically:

[0076] During acceleration: the system adjusts the current output of the capacitor through the intelligent charge and discharge control module, quickly responds to the power requirements of the electric motor, and provides high-power electrical energy support;

[0077] During braking: the braking energy of the electric bus is recovered and stored in the supercapacitor, and the kinetic energy is converted into electrical energy through the reverse operation of the electric motor, improving the energy efficiency of the system;

[0078] Temperature and voltage monitoring: temperature sensors and voltage monitoring devices ensure that the capacitor does not overheat or overcharge or over-discharge during high-power operation, ensuring the stability and safety of the system.

[0079] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Any skilled person in the art, without departing from the scope of the technical solution of the present application, according to the technical essence of the present application, any simple modification, equivalent replacement and improvement of the above embodiment, etc. still belongs to the protection scope of the technical solution of the present application.

Claims

1. A supercapacitor energy storage system with high efficiency and energy density, characterized in that: include: Supercapacitors, wherein the supercapacitors use a double-layer capacitance and pseudocapacitance composite energy storage mechanism, and the electrode materials of the supercapacitors switch between double-layer capacitance reaction and pseudocapacitance reaction; A charge and discharge control module is used to regulate the current and voltage of the supercapacitor through an embedded controller to perform energy management; the energy management is combined with the MPPT algorithm and the DPC algorithm to perform charge and discharge management; The heat dissipation module is used to dissipate heat for the supercapacitor.

2. The high-efficiency energy density supercapacitor energy storage system according to claim 1, characterized in that: The electrode material of the supercapacitor is selected from carbon-based materials, metal oxides, conductive polymers or their composite materials, and the electrolyte of the supercapacitor is selected from liquid electrolytes, solid electrolytes or gel electrolytes.

3. The high-efficiency energy density supercapacitor energy storage system according to claim 1, characterized in that: The synergistic reaction of double-layer capacitance and pseudocapacitance is formed on the surface of the electrode material of the supercapacitor, including: increasing the specific surface area of ​​the electrode surface of the double layer through surface modification, enhancing the active sites of the pseudocapacitance reaction, selecting a suitable electrolyte and voltage range, and optimizing the charge and discharge rate to make the double-layer capacitance and pseudocapacitance work synergistically.

4. The high-efficiency energy density supercapacitor energy storage system according to claim 1, characterized in that: The specific surface area of ​​the electrode material of the supercapacitor is not less than 1500m 2 / g, and an electrical conductivity better than 100S / cm; the electrolyte works stably in a temperature range of -30 to 70°C, and the ionic conductivity is not less than 10 to 2S / cm.

5. The high-efficiency energy density supercapacitor energy storage system according to claim 1, characterized in that: The surface of the electrode material of the supercapacitor is subjected to nitrogen doping modification treatment as follows: an atmosphere nitriding method is used, in which the electrode material and a nitrogen source are placed together in a high-temperature furnace and heat treated in a nitrogen or ammonia atmosphere at a temperature of 600-1000°C for a treatment time of 1-5 hours; or a liquid phase nitriding method is used, in which the electrode material is immersed in a solution containing a nitrogen source at a temperature of 300-600°C, so that the nitrogen source penetrates the surface of the electrode material and is incorporated therein.

6. The high-efficiency energy density supercapacitor energy storage system according to claim 1, characterized in that: The Nernst equation is used to optimize the ionic conductivity of the electrolyte of the supercapacitor and select the optimal electrolyte composition. The formula is as follows: Wherein, E is the electromotive force of the supercapacitor, E° is the standard electromotive force, R is the gas constant, T is the temperature, m is the number of electron transfers, F is the Faraday constant, and Q is the reaction quotient.

7. The high-efficiency energy density supercapacitor energy storage system according to claim 1, characterized in that: It also includes an integrated intelligent control system. Multiple supercapacitor units are connected in parallel to form a modular system. The integrated intelligent control system is connected to the charge and discharge control module and the heat dissipation module. The integrated intelligent control system dynamically adjusts the working status of each supercapacitor in parallel.

8. The high-efficiency energy density supercapacitor energy storage system according to claim 7, characterized in that: A voltage balancing algorithm is used to control the voltages of the supercapacitors connected in parallel to be consistent. The voltage balancing algorithm is as follows: Where V target is the target voltage, V1, V2, ..., V n is the voltage of each of the supercapacitors connected in parallel, and n is the number of the supercapacitors connected in parallel.

9. The high-efficiency energy density supercapacitor energy storage system according to claim 1, characterized in that: The charge and discharge control module uses the MPPT algorithm combined with the DPC algorithm. During the charge and discharge process, the embedded controller automatically adjusts the current and voltage. Based on the real-time data of the supercapacitor's working status, the charge and discharge strategy is dynamically adjusted as follows: The combination formula of MPPT algorithm and DPC algorithm is: P total =P mppt +P dc Where, P total is the total power of the system, P mppt is the maximum power of the supercapacitor obtained by the MPPT algorithm, P dc is the battery charge and discharge power obtained through the DPC algorithm; Power management decision formula: Where, P charge is the power required for charging, P discharge is the power required for discharge.

10. The high-efficiency energy density supercapacitor energy storage system according to claim 1, characterized in that: The heat dissipation module uses finite element analysis and thermal network analysis to simulate and optimize system heat dissipation, wherein the heat conduction efficiency of the system is calculated by the following heat conduction formula and dynamically adjusted; Where S is the heat flow, k is the thermal conductivity, A is the heat dissipation area, ΔT is the temperature difference, and d is the material thickness.

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