CN107959038B - Flow battery pulse type charging and discharging system and method for improving electrolyte utilization rate - Google Patents
Flow battery pulse type charging and discharging system and method for improving electrolyte utilization rate Download PDFInfo
- Publication number
- CN107959038B CN107959038B CN201711105693.0A CN201711105693A CN107959038B CN 107959038 B CN107959038 B CN 107959038B CN 201711105693 A CN201711105693 A CN 201711105693A CN 107959038 B CN107959038 B CN 107959038B
- Authority
- CN
- China
- Prior art keywords
- electrolyte
- charge
- charging
- discharge
- battery
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/18—Regenerative fuel cells, e.g. redox flow batteries or secondary fuel cells
- H01M8/184—Regeneration by electrochemical means
- H01M8/188—Regeneration by electrochemical means by recharging of redox couples containing fluids; Redox flow type batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
- H01M8/04186—Arrangements for control of reactant parameters, e.g. pressure or concentration of liquid-charged or electrolyte-charged reactants
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
- H01M8/04201—Reactant storage and supply, e.g. means for feeding, pipes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04276—Arrangements for managing the electrolyte stream, e.g. heat exchange
- H01M8/04283—Supply means of electrolyte to or in matrix-fuel cells
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Fuel Cell (AREA)
- Hybrid Cells (AREA)
Abstract
The invention discloses a flow battery pulse type charging and discharging system and method for improving the utilization rate of electrolyte, and belongs to the field of new energy storage. When an intermittent on-off pulse signal is input to the pulse timing power switch, the charging and discharging system is enabled to change into intermittent charging instead of continuously charging electrolyte in the flow battery. And in the period of no charging, the circulating pump still continuously operates until the charging cut-off voltage is reached, the charging process is completed, and the discharging process is entered. In the discharging process, the pulse type timing power switch is intermittently turned on and off, and the electrolyte is kept to be intermittently discharged until the discharge cut-off voltage is reached, so that the discharging process is completed. Thereby constituting a charge-discharge cycle. The invention can not only achieve the contradiction between the equilibrium concentration polarization and the pumping work, but also reduce the difference of the charge states of the electrolyte between the galvanic pile and the liquid storage tank and improve the utilization rate of the electrolyte.
Description
Technical Field
The invention belongs to the field of new energy storage, and particularly relates to a flow battery pulse type charging and discharging system and method for improving the utilization rate of electrolyte.
Background
In recent years, with the development of human production and the continuous improvement of living standard, the demand for energy has also increased. However, limited non-renewable energy sources cannot guarantee the need for sustainable development of human beings, and conventional energy supply structures mainly using fossil energy sources increasingly become bottlenecks for restricting the development of socioeconomic performance. Therefore, optimizing the energy application structure, developing renewable new energy, becomes a hot spot for common attention and research in the world.
However, the utilization of new energy is limited by time and external environment, resulting in poor stability and continuity, and also causing serious impact on the power grid. Therefore, corresponding energy storage equipment is required to be configured in the power grid system, electric energy is stored when the energy is sufficient, grid-connected power generation is performed when the electric quantity is insufficient, the contradiction between supply and demand of the energy is regulated, peak clipping and valley filling are realized, and further efficient utilization of the energy and stable and continuous electric energy output are realized.
The large-scale efficient energy storage technology is a key technology for realizing the large-scale utilization of renewable energy power generation. Redox flow batteries are currently one of the most suitable large-scale energy storage technologies for renewable new energy applications. The concept of redox flow batteries is firstly proposed by L.H.Thaller, and in recent years, research, development, engineering and industrialization of redox flow batteries are also continuously advanced, so that the redox flow batteries have a huge application prospect in the technical field of large-scale energy storage. Unlike conventional energy storage systems, the active materials of an oxidation flow battery are dissolved in their electrolyte and stored in an external liquid storage tank. In the traditional flow battery structure, positive and negative electrolyte is respectively transferred from a liquid storage tank to a pile area of the battery by two circulating pumps, and when the electrolyte flows through an electrode area, the interconversion process between chemical energy and electric energy occurs on the surface of the electrode, so that the interconversion between the electric energy and the chemical energy is realized, and the purpose of energy storage is achieved.
The electric pile of the flow battery is assembled by overlapping a plurality or dozens of single batteries in a mode of pressing the filter. Each cell unit comprises two half cells, and the constituent components thereof are as follows: solid electrodes, bipolar plates, flow frames and end plates. An ion exchange membrane is clamped between the two half batteries, and the single battery is divided into a positive reaction area and a negative reaction area, so that the ion exchange membrane has the functions of allowing proton exchange and preventing migration of other reaction ions and impurity ions. The solid electrode provides a reaction place for the electrochemical reaction, and the larger the electrode area is, the larger the charge-discharge reaction rate is, and the corresponding power is also higher. The separator between two adjacent unit cells is called a bipolar plate. The flow battery system consists of a galvanic pile, electrolyte, an electrolyte liquid storage tank, a circulating pump, a pipeline, auxiliary equipment instruments and detection protection equipment. The electrolyte reservoir is used for holding positive and negative electrolytes respectively, and is equipped with two circulating pumps for delivering the electrolytes for each half cell in a closed pipeline. The state of charge (SoC) of the battery increases during charging, and decreases during discharging.
In the charge and discharge process of the battery, the amount of the reactive substance in the electrolyte is gradually reduced, particularly, the concentration of the reactive substance is very low at the end of charge and discharge, and insufficient supply of the reactive substance is very easy to occur at the end of charge and discharge when the charge and discharge cut-off voltage range is high, so that mass transfer deterioration can be caused, larger concentration polarization is caused, and the battery efficiency is reduced. In order to ensure sufficient supply of reactants, the minimum value of the electrolyte flow rate obtained through theoretical calculation is as follows:
wherein: i is charge-discharge current, A; f is Faraday constant, about 96485C/mol; the SoC is the state of charge of the battery and can be calculated from the concentration of active ions to be reacted and generated ions in the electrolyte.
The actual flow rate of the electrolyte is:
Q＝fac×Q min
wherein: fac is the rate factor dimensionless constant.
However, the flow rate of the electrolyte is not as high as possible, and when the flow rate reaches the upper limit of a certain flow rate, the concentration polarization loss of the battery cannot be further reduced or the efficiency of the battery is improved, but the pumping work is greatly increased, the unnecessary electric energy is consumed, and the service life of the whole battery system is also affected to a certain extent. Therefore, in practical application, fac is generally 4-20 to reconcile contradiction between concentration polarization and pumping power, and maintain high battery efficiency.
However, the current flow optimization model only considers the contradiction between concentration polarization and pumping power of the flow battery, ignoring the difference of electrolyte charge states between the galvanic pile and the storage tank. The applicant found through research that the state of charge (SoC) of the electrolyte between the stack and the tank may vary during the charge and discharge of the flow battery, and especially the difference between the two may be very significant at low flow rates. For example, in the case of using 1.6mol/L of electrolyte in the all-vanadium redox flow battery, if the flow rate coefficient fac=0.5, the maximum difference in state of charge between the storage tank and the stack will be 0.8mol/L or more. When the electrolyte with high charge state flows out of the pile, the electrolyte is mixed with the electrolyte with low charge state in the storage tank, and the time difference in the process can lead to that the charge state of the electrolyte in the storage tank is always lower than that of the electrolyte in the pile. When the flow rate is very small, the difference will be very pronounced. Since the charge-discharge cut-off voltage of the battery is determined according to the state of charge collected in the cell stack, this difference will seriously affect the utilization rate of the electrolyte. In other words, when the state of charge of the electrolyte in the stack is already above the charge cut-off voltage, the state of charge of the electrolyte in the tank is still very low, which has the effect that most of the electrolyte is not utilized, which cannot be completely solved even in the case of high flow rates. Thus, it is particularly urgent to seek a method of reducing or eliminating the difference in state of charge (SoC) of the electrolyte between the stack and the tank. The method can not only improve the utilization rate of the electrolyte under any rate condition, but also improve the charging current density under the condition of low flow rate so as to improve the response performance of the flow battery.
The traditional flow battery adopts the operation mode of two storage tanks: firstly, adding electrolyte with equal volume into a positive and negative electrolyte liquid storage tank, after the battery starts to run, firstly performing a charging process, enabling the positive and negative electrolyte to enter a pile area of the battery through a circulating pump respectively, performing oxidation-reduction reaction on the surface of an electrode to increase the state of charge (SoC) of the electrolyte, enabling the electrolyte with increased state of charge (SoC) to flow out of the pile, respectively returning the electrolyte to the positive and negative electrolyte liquid storage tank again, mixing the electrolyte with low state of charge (SoC) in the electrolyte liquid storage tank, and performing circulation of the electrolyte until the voltage in the pile reaches a charging cut-off voltage. And then, carrying out a discharging process, wherein the state of charge (SoC) of the electrolyte gradually decreases until the voltage in the electric pile reaches a discharge cut-off voltage, and completing a charging and discharging cycle. In this mode of operation, if the flow rate is too low, the reactant supply in the stack is insufficient, concentration polarization increases resulting in reduced cell efficiency, while too high a flow rate increases pumping work of the system, which also reduces the efficiency of the cell system.
In order to balance the contradiction between concentration polarization and pumping power, most of the current research is optimized by adjusting the flow rate. The related art has made intensive studies, and the following technologies have emerged:
the invention patent with the application number of CN201010210100.9 discloses an all-vanadium redox flow energy storage battery system and an electrolyte flow gradient control strategy thereof, experiments are carried out in different electrolyte temperature ranges, single cell voltage ranges and current density ranges, the optimal electrolyte flow in the different electrolyte temperature ranges, the single cell voltage ranges and the current density ranges is determined on the basis of comprehensively considering the energy efficiency and the power consumption of the all-vanadium redox flow energy storage battery system, and the working frequency and the flow of a pump are controlled by a single chip microcomputer to ensure that the all-vanadium redox flow energy storage battery system operates under the selected electrolyte flow.
The invention patent with the application number of CN201410746201.6 discloses an electrolyte flow optimization control method of an all-vanadium redox flow battery system, and provides a control strategy for increasing the electrolyte flow in a sectional manner in the charging and discharging process of a battery, and in the running process of the battery, the required electrolyte flow is calculated according to a charging and discharging state value SOC acquired by a charging and discharging state monitor, and the working frequency of a centrifugal pump is regulated through a frequency converter, so that the all-vanadium redox flow battery system is ensured to run at a selected flow.
However, the above patent focuses only on the contradiction between the harmonic equilibrium concentration polarization and pumping power, and does not focus on the difference in state of charge (SoC) of the electrolyte between the stack and the reservoir. Even at relatively high flow rates, this difference is not completely resolved. Moreover, this manner of regulating flow is believed to prevent the flow cell system from operating at lower flow rates with some loss of pumping power. At present, only very low current densities can be adopted under the condition of low flow rate, so that the supply of reactive substances in the galvanic pile is not too small.
There are also studies on the operation of pumps by the skilled person. The following techniques occur:
the invention application number CN201410241236.4 discloses a liquid flow pump intermittent operation automatic controller of a lithium ion liquid flow battery, which is added to a lithium ion liquid flow battery system, can automatically judge the service condition of the lithium ion liquid flow battery, fully and automatically start and stop the liquid flow pump, intermittently operate, intermittently circulate positive and negative suspension liquid of the lithium ion liquid flow battery, and circulate out after the reaction of a positive and negative reaction cavity of the lithium ion liquid flow battery is completed. The mode can reduce the working time of the liquid flow pump and reduce the pumping work. However, this form cannot accurately control the volume of the electrolyte entering the stack each time, and requires judgment of the reaction time required for the electrolyte entering the stack each time, which presents a certain difficulty in the automated operation of the system.
The invention application No. CN201610801986.1 discloses a current interrupter for a flow battery and the flow battery adopting the current interrupter, wherein the current interrupter for the flow battery is additionally arranged on an outlet pipeline of an electric pump, and the current interrupter part enables liquid flow to intermittently flow in a rotating mode, so that electrolyte is intermittently fed into each pile section by section, and the electrolyte in an electrolyte pipeline is intermittently disconnected. The "current interrupter" described in this way also essentially has the effect of "intermittent circulation of the electrolyte", but the structure is relatively complex, which corresponds to a sacrifice of the output power of the cells in the stack for the cells that are disconnected by the electrolyte.
Disclosure of Invention
The invention aims to solve the problems in the prior art, and provides a flow battery pulse type charge and discharge system and a method for improving the utilization rate of electrolyte.
The pulse type charge and discharge system of the flow battery disclosed by the invention can be used for reducing the difference of the state of charge (SoC) of the electrolyte between a galvanic pile and a liquid storage tank and improving the utilization rate of the electrolyte by improving the operation mode of the charge and discharge system of the battery, and has the advantages of flow optimization and pump operation mode optimization, which are not possessed by the situation that the current density is higher under the condition of low flow rate.
The pulsed charging and discharging system of the flow battery is realized by the following technical scheme:
the pulsed charging and discharging system of the flow battery for improving the utilization rate of the electrolyte has the following structure: the electrolyte stack end plates on two sides of the flow battery are provided with an anode electrolyte inlet, a cathode electrolyte inlet, an anode electrolyte outlet and a cathode electrolyte outlet, and the anode electrolyte inlet and the anode electrolyte outlet are connected with an anode electrolyte liquid storage tank through a transfusion pipeline to form a circulation loop of anode electrolyte; the negative electrode electrolyte inlet and the negative electrode electrolyte outlet are connected with a negative electrode electrolyte storage tank through a transfusion pipeline to form a negative electrode electrolyte circulation loop; the infusion pipelines are provided with circulating pumps for providing electrolyte conveying power; stirring devices are arranged in the positive electrolyte storage tank and the negative electrolyte storage tank; the flow battery collector is externally connected with a charge-discharge system, and the charge-discharge system comprises a battery charge-discharge detection device and a pulse timing power switch which is connected in series in a charge-discharge circuit of the battery charge-discharge detection device and the flow collector and is used for controlling intermittent on-off of the charge-discharge circuit.
Preferably, the pulse timing power switch is connected with a computer for inputting pulse control signals.
Preferably, the stirring device is a magnetic rotor.
Preferably, the stack structure of the flow battery is as follows: a plurality of single cell structural units are clamped between the PP plates at two sides, and pile end plates are respectively fixed outside the PP plates at two sides.
Preferably, the flow battery is an all-vanadium flow battery, a zinc-bromine flow battery or a zinc-nickel flow battery.
Another object of the present invention is to provide a method for improving the utilization rate of an electrolyte by using the above system, which comprises the following steps:
firstly, adding an equal volume of electrolyte into an anode electrolyte liquid storage tank and a cathode electrolyte liquid storage tank, and respectively starting a stirring device in the two liquid storage tanks to uniformly mix the electrolyte in the tanks; starting a circulating pump to enable positive and negative electrolyte to flow in a transfusion pipeline, enabling the positive and negative electrolyte to enter a single cell structure unit in the electric pile through an electric pile end plate, an electric pile PP plate, a positive electrolyte inlet and a negative electrolyte inlet respectively, and enabling redox reaction to occur in the single cell to increase the charge state of the electrolyte, and enabling the electrolyte to return to a positive electrolyte liquid storage tank and a negative electrolyte liquid storage tank respectively through a positive electrolyte liquid outlet and a negative electrolyte liquid outlet to form a circulating loop; according to the theoretical charging time and the theoretical discharging time calculated by the volume of the positive and negative electrolyte, the charging and discharging time is divided into a plurality of time periods and is input into a computer, the on-off state of a pulse type timing power switch is controlled, so that a battery charging and discharging detection device outputs pulse type current, and the electrolyte is intermittently charged in a galvanic pile; the circulating pump driving the positive and negative electrolyte to circulate still keeps running in the period that the charge and discharge detection device is not charged in the pulse period; when the collector plate of the external charging and discharging system collects the voltage of the battery to reach the charging cut-off voltage, the charging is finished, the discharging process is started, the system still keeps the pulse type ground discharging process until the collector plate of the external charging and discharging system collects the voltage of the battery to reach the discharging cut-off voltage, the discharging process is finished, and a complete charging and discharging cycle is completed.
Preferably, the total charge time is not less than the theoretical charge time and the total discharge time is not less than the theoretical discharge time in each pulse period of the charge or discharge.
Preferably, the charge cutoff voltage is set to 1.7V.
Preferably, the discharge cutoff voltage is set to 0.8V.
The pulse type charging and discharging system of the flow battery controls the on and off of the pulse type timing power switch through the computer, so that the battery charging and discharging detection device outputs pulse type current, namely: start-charge-stop … … discharge-stop-end. In the shutdown process, the two circulating pumps 6 continuously operate, so that the difference of the state of charge (SoC) of electrolyte between the cell stack and the liquid storage tank is reduced, and the concentration polarization between the cell stack and the liquid storage tank is reduced. After the shutdown process is finished, the pulse type timing power switch is closed, and the system continues to charge or discharge. Finally, when the charge and discharge are cut off, the utilization rate of the electrolyte can be effectively improved, and particularly under the condition of low flow rate, the utilization rate of the electrolyte can be obviously improved.
Compared with the prior art, the invention has the following characteristics: first, the utilization ratio of the positive and negative electrolyte is obviously increased, so that the difference of the state of charge (SoC) of the electrolyte between a cell stack and a liquid storage tank can be greatly reduced, and the concentration polarization between the cell stack and the liquid storage tank is reduced. Second, the battery can be kept charged and discharged for a long time under the condition of low flow rate, and the battery can be kept to work normally under the condition of high current density when the flow rate is low. Third, under the condition that the volume of the liquid storage tank is larger, the electrolyte in the liquid storage tank can be ensured to keep good uniformity, and the influence of uneven mixing of the electrolyte on the battery is avoided.
Drawings
Fig. 1 is a basic schematic diagram of a pulse charge-discharge system of a flow battery for improving the utilization rate of an electrolyte in an embodiment of the present invention.
FIG. 2 is a schematic view of the liquid inlet and outlet of the positive electrode electrolyte of the device of FIG. 1 according to the present invention.
Fig. 3 is a schematic view of a liquid inlet and a liquid outlet of the negative electrode electrolyte of the device shown in fig. 1 in the present invention.
Fig. 4 is a relationship between the electrolyte utilization rate of the device according to the present invention and the conventional device according to the flow rate β.
In the figure: the cell stack comprises a cell stack end plate 1, a cell stack PP plate 2, a single cell structure unit 3, a transfusion pipeline 4, a positive electrolyte liquid storage tank 5, a circulating pump 6, a negative electrolyte liquid storage tank 7, a magnetic rotor 8, a battery charge and discharge detection device 9, a pulse type timing power switch 10, a computer 11, a positive electrolyte liquid outlet 12, a positive electrolyte liquid inlet 13, a current collecting plate 14, a bolt hole 15, a negative electrolyte liquid outlet 16 and a negative electrolyte liquid inlet 17.
Detailed Description
The invention is further illustrated and described below with reference to the drawings and detailed description. The technical features of the embodiments of the invention can be combined correspondingly on the premise of no mutual conflict.
As shown in fig. 1 to 3, in the embodiment, the flow battery pulse type charge and discharge system for improving the utilization rate of the electrolyte is mainly composed of three parts, and is mainly divided into a pile part of the battery, an external circulation part of the electrolyte and a charge and discharge system (external power supply) part of the battery. The main components of the device comprise a pile end plate 1, a PP plate 2, a single cell structure unit 3, a transfusion pipeline 4, a positive electrolyte liquid storage tank 5, a circulating pump 6, a negative electrolyte liquid storage tank 7, a magnetic rotor 8, a battery charge and discharge detection device 9, a pulse type timing power switch 10, a computer 11, a positive electrolyte liquid outlet 12, a positive electrolyte liquid inlet 13, a current collecting plate 14, a bolt hole 15, a negative electrolyte liquid outlet 16 and a negative electrolyte liquid inlet 17.
The pile part of the battery mainly comprises a pile end plate 1 (a stainless steel end plate can be adopted), a PP plate 2 (a polyethylene material can be adopted for ensuring uniform distribution of pretightening force of the battery everywhere) and a plurality of single-cell structural units 3, wherein bolt holes 15 are formed in the pile end plate 1 in the circumferential direction for fastening and fixing. A plurality of single cell structural units 3 are clamped between the two side PP plates 2, and pile end plates 1 are respectively fixed outside the two side PP plates 2. The number of the unit cell structure units 3 is not limited. Each unit cell structure unit 3 can be further divided into main components such as a current collecting plate 14 (a copper plate can be used for collecting the charging state of a unit cell from a bipolar plate and converting the charging state into a voltage signal, and simultaneously, the current of an external power supply is also transmitted into the cell to control the charging or discharging of the cell), a bipolar plate (a graphite plate can be used for distinguishing the positive electrode and the negative electrode of an electrolyte and conducting an electric signal), a liquid flow frame, a sealing gasket, an electrode (a graphite felt can be used for providing an active area for the electrochemical reaction of the electrolyte), an ion exchange membrane (a Nafion117 cation exchange membrane can be used for transmitting hydrogen ions and water molecules at the positive electrode and the negative electrode of the cell and keeping the charge balance of the cell), and the like.
The pile end plates 1 on two sides of the flow battery are provided with an anode electrolyte inlet 13, a cathode electrolyte inlet 17, an anode electrolyte outlet 12 and a cathode electrolyte outlet 16, and the anode electrolyte inlet 13 and the anode electrolyte outlet 12 are connected with an anode electrolyte liquid storage tank 5 through a transfusion pipeline to form a circulation loop of anode electrolyte; the negative electrode electrolyte inlet 17 and the negative electrode electrolyte outlet 16 are connected with the negative electrode electrolyte liquid storage tank 7 through a transfusion pipeline to form a negative electrode electrolyte circulation loop. And the infusion pipelines of the anode and the cathode are respectively provided with a circulating pump 6 for providing electrolyte conveying power, and peristaltic circulating pumps are preferably used for realizing flow adjustability. And magnetic rotors 8 are arranged in the positive electrolyte storage tank 5 and the negative electrolyte storage tank 7 and are used for stirring the electrolyte. The current collecting plate 14 of the flow battery is externally connected with a charge-discharge system, the charge-discharge system comprises a battery charge-discharge detection device 9 and a pulse timing power switch 10, and the battery charge-discharge detection device 9 is used for outputting current to the current collecting plate 14 when being used as a power supply and is communicated with a circuit, and simultaneously can detect state information such as voltage, battery capacity and the like at the current collecting plate 14 in real time. The on-off of the circuit is controlled by the pulse type timing power switch 10 according to the pulse signal stored internally or received from the outside, and the pulse type timing power switch 10 is realized by adopting a programmable control timing switch in the embodiment. The pulse timing power switch 10 is connected in series with the battery charge and discharge detection device and the charge and discharge circuit of the current collecting plate 14, and the whole turn-off control circuit of the pulse timing power switch 10 is turned on and off, so that intermittent on-off of the charge and discharge circuit can be controlled according to intermittent on-off pulse control signals. As shown in fig. 4, the device of the present invention has a greatly improved electrolyte utilization rate at a low flow rate β compared to the electrolyte utilization rate of the conventional device.
Based on the device, the method for improving the utilization rate of the electrolyte comprises the following steps: when an intermittent on-off pulse signal is input to the pulse timing power switch 10, the charging and discharging system is changed into intermittent charging instead of continuously charging the electrolyte in the flow battery. In the period of no charging, the circulating pump 6 still continuously operates, and the electrolyte in the electric pile and the electrolyte in the electrolyte storage tank are fully and uniformly mixed, so that the difference of the state of charge (SoC) of the electrolyte between the battery electric pile and the electrolyte storage tank is reduced until the charging cut-off voltage is reached, and the charging process is completed and the discharging process is entered. In the discharging process, the pulse type timing power switch 10 is also intermittently turned on and off, and the electrolyte is kept to be intermittently discharged until the discharge cut-off voltage is reached, so that the discharging process is completed. Thereby constituting a charge-discharge cycle.
The specific method for improving the utilization rate of the electrolyte is described in detail below, and the steps are as follows:
firstly, the electrolyte with the same volume is added into the positive electrolyte liquid storage tank 5 and the negative electrolyte liquid storage tank 7, and a magnetic rotor 8 is respectively added into the two liquid storage tanks, so that the uniformity of electrolyte mixing during system operation is ensured. The circulating pump 6 is started to enable positive and negative electrolyte to flow in the infusion pipeline 4, and the positive and negative electrolyte respectively enters the single cell structural unit 3 in the electric pile through the electric pile end plate 1, the electric pile PP plate 2, the positive electrolyte inlet 13 and the negative electrolyte inlet 17, oxidation-reduction reaction occurs in the single cell, the state of charge (SoC) of the electrolyte is increased after the reaction is completed, and the electrolyte returns to the positive electrolyte liquid storage tank 5 and the negative electrolyte liquid storage tank 7 through the positive electrolyte liquid outlet 12 and the negative electrolyte liquid outlet 16 respectively. The theoretical charging and discharging time is calculated according to the volume of the positive and negative electrolyte, the theoretical charging and discharging time is divided into a plurality of time periods and is input into the computer 11 (preferably divided into 5-20 time periods), the state of the pulse type timing power switch 10 is controlled, so that the battery charging and discharging detection device outputs pulse type current, namely: start-charge-stop … … discharge-stop-end, the stop time is not limited (as long as the electrolyte can be sufficiently mixed, preferably 1 min). When the pulse-type timing power switch 10 is connected, the battery charge/discharge detection device 9 starts outputting current to the collector 14, and the system is charged in a predetermined pulse-type charge/discharge manner. In the shutdown process, the two circulating pumps 6 continuously operate, so that the difference of the state of charge (SoC) of electrolyte between the cell stack and the liquid storage tank is reduced, and the concentration polarization between the cell stack and the liquid storage tank is reduced. The pulse-timing power switch 10 is then closed again and the system continues the charging process. The above pulse process is reciprocally cycled n times, and when the collector plate 14 externally connected with the charge and discharge system collects that the voltage of the battery has reached the charge cut-off voltage (preferably, the charge cut-off voltage is set to be 1.7V), the charge is ended, and the discharge process is started. At this time, the system still keeps the pulse-type discharging process until the collector plate 14 of the external charging and discharging system collects that the voltage of the battery has reached the discharge cut-off voltage (preferably, the discharge cut-off voltage is set to be 0.8V), and the discharging process is finished, thus completing a complete charging and discharging cycle.
The above embodiment is only a preferred embodiment of the present invention, but it is not intended to limit the present invention. Various changes and modifications may be made by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present invention. For example, the specific structure of the flow battery may be in various manners in the art, and is not limited to the structure described in the embodiments. Therefore, all the technical schemes obtained by adopting the equivalent substitution or equivalent transformation are within the protection scope of the invention.
Claims (9)
1. The pulsed charging and discharging system of the flow battery for improving the utilization rate of electrolyte is characterized in that a positive electrolyte inlet (13), a negative electrolyte inlet (17), a positive electrolyte outlet (12) and a negative electrolyte outlet (16) are formed in pile end plates (1) on two sides of the flow battery, and the positive electrolyte inlet (13) and the positive electrolyte outlet (12) are connected with a positive electrolyte storage tank (5) through a transfusion pipeline to form a circulating loop of positive electrolyte; the negative electrode electrolyte inlet (17) and the negative electrode electrolyte outlet (16) are connected with a negative electrode electrolyte storage tank (7) through a transfusion pipeline to form a negative electrode electrolyte circulation loop; the infusion pipelines are provided with circulating pumps (6) for providing electrolyte conveying power; stirring devices are arranged in the positive electrolyte liquid storage tank (5) and the negative electrolyte liquid storage tank (7); the flow battery collector (14) is externally connected with a charge and discharge system, the charge and discharge system comprises a battery charge and discharge detection device (9) and a pulse type timing power switch (10), and the pulse type timing power switch (10) is connected in series in a charge and discharge circuit of the battery charge and discharge detection device and the flow collector (14) and is used for controlling intermittent on-off of the charge and discharge circuit.
2. The flow battery pulse type charge and discharge system for improving the utilization rate of electrolyte according to claim 1, wherein the pulse type timing power switch (10) is connected with a computer (11) for inputting pulse control signals.
3. The flow battery pulse charging and discharging system for improving the utilization rate of electrolyte according to claim 1, wherein the stirring device is a magnetic rotor (8).
4. The pulsed charge and discharge system of a flow battery for increasing electrolyte utilization of claim 1, wherein the flow battery has a stack structure of: a plurality of single cell structural units (3) are clamped between the PP plates (2) at the two sides, and pile end plates (1) are respectively fixed outside the PP plates at the two sides.
5. The pulsed charge-discharge system of the flow battery for improving the utilization rate of the electrolyte according to claim 1, wherein the flow battery is an all-vanadium flow battery, a zinc-bromine flow battery or a zinc-nickel flow battery.
6. A method for increasing electrolyte utilization using the system of claim 2, comprising the steps of: firstly, adding electrolyte with equal volume into an anode electrolyte liquid storage tank (5) and a cathode electrolyte liquid storage tank (7), and respectively starting a stirring device in the two liquid storage tanks to uniformly mix the electrolyte in the tanks; starting a circulating pump (6) to enable positive and negative electrolyte to flow in a transfusion pipeline (4), and enabling the positive and negative electrolyte to enter a single cell structure unit (3) in the electric pile through an electric pile end plate (1), an electric pile PP plate (2), an positive electrolyte inlet (13) and a negative electrolyte inlet (17) respectively, wherein oxidation-reduction reaction occurs in the single cell to increase the charge state of the electrolyte, and the electrolyte returns to an positive electrolyte liquid storage tank (5) and a negative electrolyte liquid storage tank (7) through a positive electrolyte liquid outlet (12) and a negative electrolyte liquid outlet (16) respectively to form a circulating loop; according to the theoretical charging time and the theoretical discharging time calculated by the volume of the positive and negative electrolyte, the charging and discharging time is divided into a plurality of time periods and is input into a computer (11), the on-off state of a pulse type timing power switch (10) is controlled, the battery charging and discharging detection device outputs pulse type current, and the electrolyte is intermittently charged in a galvanic pile; the circulating pump (6) for driving the positive and negative electrolyte to circulate still keeps running in the period that the charge and discharge detection device is not charged in the pulse period; when the collector plate (14) of the external charging and discharging system collects that the voltage of the battery has reached the charging cut-off voltage, the charging is finished, the discharging process is started, the system still keeps the pulse type ground discharging process until the collector plate (14) of the external charging and discharging system collects that the voltage of the battery has reached the discharging cut-off voltage, the discharging process is finished, and a complete charging and discharging cycle is completed.
7. The method of claim 6, wherein the total charge time is not less than said theoretical charge time and the total discharge time is not less than said theoretical discharge time during each pulse period of the charge or discharge.
8. The method of claim 6, wherein the charge cutoff voltage is set to 1.7V.
9. The method of claim 6, wherein the discharge cutoff voltage is set to 0.8V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711105693.0A CN107959038B (en) | 2017-11-10 | 2017-11-10 | Flow battery pulse type charging and discharging system and method for improving electrolyte utilization rate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711105693.0A CN107959038B (en) | 2017-11-10 | 2017-11-10 | Flow battery pulse type charging and discharging system and method for improving electrolyte utilization rate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107959038A CN107959038A (en) | 2018-04-24 |
| CN107959038B true CN107959038B (en) | 2023-06-02 |
Family
ID=61964522
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711105693.0A Active CN107959038B (en) | 2017-11-10 | 2017-11-10 | Flow battery pulse type charging and discharging system and method for improving electrolyte utilization rate |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107959038B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109728314B (en) * | 2018-12-13 | 2020-12-11 | 浙江大学 | Flow battery structure with magnetic particle attached electrode of external magnetic field and method |
| CN114263567B (en) * | 2021-12-08 | 2024-04-02 | 广东力恒新能源科技有限公司 | Iron-chromium liquid flow energy storage battery system |
| CN115020756B (en) * | 2022-06-13 | 2023-07-25 | 燕山大学 | Zinc-bromine/iodine double flow battery |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202121013U (en) * | 2011-05-13 | 2012-01-18 | 安徽硕日光电科技有限公司 | Intelligent on-line monitoring management system of large capacity vanadium ion redox flow battery |
| CN103762693A (en) * | 2014-02-07 | 2014-04-30 | 清华大学 | Circuit structure for charge and discharge of vanadium redox battery and control method thereof |
| CN104143646A (en) * | 2013-05-09 | 2014-11-12 | 中国科学院大连化学物理研究所 | Flow energy storage cell or pile running method |
| WO2015117262A1 (en) * | 2014-02-07 | 2015-08-13 | 清华大学 | Circuit and adaptive control method for suppressing self-starting surge current of vanadium battery |
| CN207426029U (en) * | 2017-11-10 | 2018-05-29 | 浙江大学 | A kind of flow battery pulsed charge-discharge system for improving electrolyte utilization rate |
-
2017
- 2017-11-10 CN CN201711105693.0A patent/CN107959038B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202121013U (en) * | 2011-05-13 | 2012-01-18 | 安徽硕日光电科技有限公司 | Intelligent on-line monitoring management system of large capacity vanadium ion redox flow battery |
| CN104143646A (en) * | 2013-05-09 | 2014-11-12 | 中国科学院大连化学物理研究所 | Flow energy storage cell or pile running method |
| CN103762693A (en) * | 2014-02-07 | 2014-04-30 | 清华大学 | Circuit structure for charge and discharge of vanadium redox battery and control method thereof |
| WO2015117262A1 (en) * | 2014-02-07 | 2015-08-13 | 清华大学 | Circuit and adaptive control method for suppressing self-starting surge current of vanadium battery |
| CN207426029U (en) * | 2017-11-10 | 2018-05-29 | 浙江大学 | A kind of flow battery pulsed charge-discharge system for improving electrolyte utilization rate |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107959038A (en) | 2018-04-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Huang et al. | Vanadium redox flow batteries: Flow field design and flow rate optimization | |
| CN109037725B (en) | Flow battery capable of improving distribution uniformity of electrolyte, electrode structure and method | |
| CN107394243B (en) | Flow battery energy storage system and system with intermittent energy source | |
| CN102299362B (en) | Electrolyte flow stepped control strategy of vanadium redox energy storage battery system | |
| US20070072067A1 (en) | Vanadium redox battery cell stack | |
| Hsieh et al. | Measurement of local current density of all-vanadium redox flow batteries | |
| Liu et al. | No-mixing design of vanadium redox flow battery for enhanced effective energy capacity | |
| CN107959038B (en) | Flow battery pulse type charging and discharging system and method for improving electrolyte utilization rate | |
| CN201549546U (en) | Columnar flow battery device | |
| CN104143646A (en) | Flow energy storage cell or pile running method | |
| CN109713339B (en) | Flow battery system control method based on current optimization strategy | |
| CN218299838U (en) | All-vanadium redox flow battery with gravity energy storage function | |
| CN202712342U (en) | Fuel cell device | |
| CN207426029U (en) | A kind of flow battery pulsed charge-discharge system for improving electrolyte utilization rate | |
| CN208460880U (en) | A kind of flow battery and electrode structure improving electrolyte distributing homogeneity | |
| CN105702980B (en) | A kind of online control method and its system for restoring flow battery system performance | |
| Li et al. | Design and development of large-scale vanadium redox flow batteries for engineering applications | |
| CN109728314A (en) | A kind of the flow battery structure and method of the magnetic-particle adhesive electrodes of externally-applied magnetic field | |
| CN107946617B (en) | Four-storage-tank flow battery structure and method for improving electrolyte utilization rate | |
| CN107565151B (en) | Regeneration method of electrode activity of all-vanadium redox flow battery | |
| CN104300169A (en) | Alkaline zinc vanadium flow battery | |
| CN207426026U (en) | A kind of four storage tank flow battery structures for improving electrolyte utilization rate | |
| CN206349448U (en) | A kind of pile of redox flow batteries | |
| Wang | Research on All-Vanadium Redox Flow Battery Energy Storage Device Based on Energy-Saving and Environmentally-Friendly New Energy Power Station Interface Technology | |
| CN117276614B (en) | Energy storage system with hydrogen peroxide as electronic energy carrier |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |