KR101942904B1 - Module for mixing of electrolyte and method for mixing of electrolyte for flow battery using the same - Google Patents

Abstract

The present invention relates to an electrolyte mixing module applicable to a flow battery and a method of mixing an electrolyte of a flow battery using the same. More particularly, an initial state electrolyte is oxidized / reduced at a cathode and an anode of a flow battery, The electrolytic solution of the pentavalent can be relatively easily reduced by the tetravalent electrolytic solution. Further, by using the electrolytic solution of 3.5 volts by uniformly mixing the tetravalent and trivalent electrolytic solutions, The present invention relates to an electrolyte mixture module applicable to a flow battery capable of improving the utilization efficiency of a negative electrode and a positive electrode electrolyte of a battery, and a method of mixing an electrolyte of a flow battery using the same.

Description

BACKGROUND OF THE INVENTION Field of the Invention [0001] The present invention relates to an electrolytic solution mixing module applicable to a flow battery, and a method of mixing an electrolytic solution of a flow battery using the electrolytic solution mixing module.

The present invention relates to an electrolyte mixing module applicable to a flow battery and a method of mixing an electrolyte of a flow battery using the same. More specifically, an initial state electrolyte is oxidized / reduced in a cathode and an anode of a flow battery, The electrolytic solution of the pentavalent electrolytic solution can be relatively easily reduced to the tetravalent electrolytic solution by the introduction of the ionic reducing agent into the cathode electrolytic solution storage portion and the tetragonal and trivalent electrolytic solutions are uniformly mixed to form the 3.5- And more particularly, to an electrolyte mixing module applicable to a flow battery capable of improving the utilization efficiency of a negative electrode and a positive electrode electrolyte of a flow battery, and a method of mixing an electrolyte of a flow battery using the same.

Power storage technology is an important technology for efficient use of energy, such as efficient use of power, improvement of power supply system's ability and reliability, expansion of new and renewable energy with a large fluctuation over time, energy recovery of mobile body, There is a growing demand for possibilities and social contributions.

The supply and demand balances of semi-autonomous regional electricity supply systems such as micro grid and the uneven output of renewable energy such as wind power and solar power are appropriately distributed and voltage and frequency fluctuations Researches on secondary batteries have been actively conducted to control the influence of secondary batteries, and expectations for utilization of secondary batteries are increasing in these fields.

Particularly, the characteristics required for a secondary battery to be used for a large-capacity power storage have to be high in energy storage density, and a redox flow battery (RFB) as a secondary battery with high capacity and high efficiency suitable for such characteristics has recently been attracting attention It is true.

The redox flow battery converts the electrical energy input through the charging process into chemical energy and stores it, and converts the stored chemical energy into electric energy through the discharging process. However, such a redox flow battery is different from a general secondary battery in that a tank or a storage container for storing an electrode active material is required because an electrode active material having energy is present in a liquid state rather than a solid state.

As such, the redox flow battery is capable of large capacity, low maintenance cost, can operate at room temperature, and can design the capacity and output independently. Therefore, many studies have been made with the large capacity secondary battery .

Among them, the vanadium redox flow battery using vanadium ion receives the light as a next-generation energy storage device, but the cross-over phenomenon of the vanadium ion separation membrane (or ion exchange membrane), the hydrogen generation at the cathode, There is a problem in that the capacity of the redox flow battery is lowered due to the oxidation reaction of the vanadium ion in the city.

In the case of a vanadium redox flow battery, a vanadium sulfate solution is prepared by using VOSO ₄ as a vanadium precursor in the production of an electrolyte solution used as an anode and a cathode electrolyte. At this time, It is necessary to carry out an electrochemical ion separation process in which the cathode is oxidized to a trivalent electrolyte and the anode is oxidized to a pentavalent electrolytic solution. Here, the electrolytic solution oxidized by the pentavalent electrolytic solution in the tetravalent electrolytic solution through the ion separation process is mostly discarded, and when it is recycled, the electrolytic solution should be reduced to 4 or less electrolytic solution by chemical or electrochemical method.

Among the conventional studies, there has been studied a method of reducing an electrolyte oxidized with a pentavalent electrolytic solution from an anode to a tetravalent electrolytic solution. However, in the case of an organic reducing agent containing carbon, an excess amount of organic materials, There is a problem that side reactions may occur during the reaction.

Japanese Patent Application Laid-Open No. 2001-167787

SUMMARY OF THE INVENTION The present invention has been conceived in order to solve the above-mentioned problems, and an object of the present invention is to provide a method for producing a tetravalent electrolytic solution by using an electrolytic solution of a tetravalent electrolytic solution, To an electrolytic solution mixing module that can be applied to a flow battery capable of reducing the electrolytic solution relatively easily without recycling the pentavalent electrolytic solution and without recycling the pentavalent electrolytic solution without further battery reaction and to provide a method for mixing an electrolyte solution of a flow battery using the same will be.

Specifically, it is an object of the present invention to provide a method and an apparatus for separating and purifying electrolytes in an electrolytic solution in which electrolytic solution of initial state is oxidized / reduced and separated from a cathode and an anode of a flow battery, Applicable to a flow battery capable of improving the utilization efficiency of a negative electrode and a positive electrode electrolyte of a flow battery by using a 3.5-valent electrolytic solution by uniformly mixing a tetra- and tri-valent electrolytic solution and relatively reducing the electrolytic solution with a tetravalent electrolytic solution And a method of mixing an electrolyte of a flow battery using the same.

The present invention relates to an electrolyte mixing module applicable to a flow battery, comprising: a negative electrode and a positive electrode electrolyte reservoir configured to store at least one of a negative electrode and a positive electrode electrolyte; An ion reductant input unit for supplying an ion reductant to the anode electrolyte storage unit; And a first valve and a second valve for discharging the negative electrode and the positive electrode electrolyte from the negative electrode and the positive electrode electrolyte outlet to the negative electrode and the positive electrode electrolyte reservoir, respectively.

Preferably, the negative electrode and the positive electrode electrolyte are oxidized / reduced at the negative electrode and the positive electrode of the flow battery, respectively.

Preferably, the first valve and the second valve are three-way valves.

Preferably, the electrolyte mixing module further comprises a controller, and the controller controls whether the first and second valves are open or closed and the electrolyte flow direction.

Preferably, the controller controls the first valve so that the cathode electrolyte discharged from the cathode flows into the anode electrolyte storage part, and the cathode electrolyte is discharged from the cathode by controlling the second valve, To be introduced.

Preferably, the controller controls the first valve to allow the negative electrode electrolyte flowing out of the negative electrode to flow into the negative electrode electrolyte storage part, and the positive electrode electrolyte discharged from the positive electrode by controlling the second valve is stored in the negative electrode electrolyte storage To be introduced.

Preferably, the cathode electrolyte storage portion is further provided with a gas valve, and the gas valve is configured to discharge gas generated when the ion reducing agent is introduced.

Preferably, the negative electrode and the positive electrode electrolyte reservoir are provided with a graduation-type metering section for measuring the volume of the stored negative electrode and positive electrode electrolyte.

Preferably, the cathode and the anode electrolyte storage are further provided with a volumetric sensor capable of measuring the volume of the stored cathode and anode electrolyte.

Preferably, the electrolyte mixing module includes a pump capable of connecting one side to the cathode electrolyte storage part and the other side to be connected to the cathode electrolyte inlet, one side being connectable to the anode electrolyte storage part and the other side being connectable to the anode electrolyte inlet Respectively.

Preferably, the electrolyte solution mixing module includes a separator between the cathode and the anode.

Preferably, the electrolyte mixing module further comprises an agitator capable of stirring the negative electrode and the positive electrode electrolyte stored in the negative electrode and the positive electrode electrolyte reservoir, respectively.

Preferably, the stirring device is any one of an impeller, an agitator, and a magnetic stirrer.

Preferably, the ionic reducing agent is hydrazine monohydrate (N ₂ H ₄ .H ₂ O).

Preferably, the flow battery is a vanadium redox flow battery.

The present invention relates to an electrolyte solution mixing method for a flow battery, comprising the steps of: (a) introducing an initial state electrolytic solution into a cathode and a cathode electrolyte inlet; (b) oxidizing / reducing the initial state electrolyte at the cathode and the anode of the flow battery; (c) introducing the oxidized / reduced cathode and the anode electrolyte into one or more of the cathode and the anode electrolyte reservoir; And (d) an ionic reducing agent is introduced into the anode electrolyte storage part.

Preferably, in the step (a), the initial state electrolytic solution is introduced into the cathode and the anode electrolyte reservoir.

Preferably, the step (a) and the step (d) further include stirring the negative electrode and the positive electrode electrolyte stored in the negative electrode and the positive electrode electrolyte reservoir, respectively.

Preferably, the step (d) further comprises discharging the gas generated when the ionic reducing agent is introduced.

Preferably, the method further comprises: (e) mixing the negative electrode electrolyte stored in the negative electrode electrolyte reservoir with the positive electrode electrolyte stored in the positive electrode electrolyte reservoir.

Preferably, the flow battery is a vanadium redox flow battery.

According to the present invention, when a tetravalent electrolytic solution is prepared by using an electrochemical process using a trivalent electrolytic solution, the pentavalent electrolytic solution necessarily generated is reduced to a tetravalent electrolytic solution by adding an ionic reducing agent, Thereby reducing battery production and manufacturing costs.

In addition, according to the present invention, the effect of improving the process efficiency is obtained by reducing the electrolytic solution relatively easily without additional battery reaction by reducing the pentavalent electrolytic solution to the tetravalent electrolytic solution by inputting the ion reducing agent.

In addition, according to the present invention, the initial state electrolytic solution is oxidized / reduced and ion-separated from the cathode and the anode of the flow battery and then introduced into the cathode and anode electrolyte reservoir, and then the ion reductant is charged into the anode electrolyte reservoir, It is possible to relatively easily reduce the amount of the electrolytic solution by using the electrolytic solution. Further, the use efficiency of the negative electrode and the positive electrode electrolytic solution of the flow battery can be improved by using the 3.5-valent electrolytic solution by uniformly mixing the tetra- and trivalent electrolytic solutions.

1 is a schematic view showing a general structure of a redox flow battery.
FIG. 2 is a view schematically showing a state in which an electrolyte mixing module 100 according to an embodiment of the present invention is applied to a flow battery.
3 is a flowchart illustrating a method of mixing an electrolyte of a flow battery according to an embodiment of the present invention.
FIG. 4 is a graph showing the results of oxidation of a sulfuric acid solution in which VOSO ₄ is dissolved according to an electrolytic solution mixing method of a flow battery according to an embodiment of the present invention by electrochemical oxidation to a pentavalent vanadium solution and then adding hydrazine monohydrate (N ₂ H ₄ .H ₂ O) was injected into the electrolyte solution to change the state of the tetravalent vanadium solution.

The present invention will now be described in detail with reference to the accompanying drawings. Hereinafter, a repeated description, a known function that may obscure the gist of the present invention, and a detailed description of the configuration will be omitted. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. Accordingly, the shapes and sizes of the elements in the drawings and the like can be exaggerated for clarity. Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

≪ Electrolyte Mixing Module >

FIG. 1 is a view schematically showing a general structure of a redox flow battery, and FIG. 2 is a schematic view illustrating a state where an electrolyte mixing module 100 according to an embodiment of the present invention is applied to a flow battery.

1, a redox flow battery generally includes a separator 31 and an electrode assembly including a cathode 32 and an anode 33 located on both sides of the separator 31, And a positive electrode electrolytic solution storage unit 20 for receiving and storing the positive electrode solution supplied to the positive electrode 33. The negative electrode electrolytic solution storage unit 10 includes:

At this time, the negative electrode electrolyte stored in the negative electrode electrolyte reservoir 10 is transferred to the negative electrode 32 through the negative electrode electrolyte inflow port 41 through the pump 11, and after the redox reaction is completed, To the cathode electrolyte storage part 10 through the cathode side. Similarly, the positive electrode electrolyte stored in the positive electrode electrolyte storage part 20 is transferred to the positive electrode 33 through the positive electrode electrolyte inflow port 42 through the pump 21, and after the redox reaction is completed, the positive electrode electrolyte outflow port 52 To the anode electrolyte storage part 20 through the anode side.

That is, when the redox flow battery is a vanadium redox flow battery, in the charging reaction, tetravalent vanadium ions are oxidized in the anode 33 to be converted into pentavalent vanadium ions and electrons are consumed, An oxidation reaction that moves from the positive electrode 33 to the negative electrode 32 occurs and the reduction reaction in which the trivalent vanadium ion accepts electrons and converts to the divalent vanadium ion occurs in the negative electrode 32. On the other hand, during the discharge reaction, the oxidation / reduction reaction (that is, the redox reaction) in which the oxidation number of the vanadium ion is changed, as opposed to the above-mentioned reaction, is performed, thereby charging and discharging are effectively performed.

The separation membrane 31 serves to transfer hydrogen ions and to block the movement of the negative electrode and vanadium ions of the positive electrode electrolyte to the counter electrode. The separator 31 has a negative electrode electrolyte reservoir 10 and a positive electrode electrolyte reservoir 20, As described above, functions to store the cathode and the anode electrolyte, and is designed to evenly distribute the internal pressures of the respective storage units or to discharge gas that may occur during operation.

2, an electrolyte mixing module 100 according to an embodiment of the present invention includes a cathode electrolyte storage portion 10, a cathode electrolyte storage portion 20, a first valve 110, a second valve 120, An ion reductant input unit 130, and a control unit 140. In addition, it may further include a gas valve 131, a gas discharge passage 132, measuring units 150 and 151, and volumetric sensors 160 and 161.

The cathode and anode electrolyte storage portions 10 and 20 serve to store at least one of the cathode and the anode electrolyte.

In this case, the materials of the cathode and anode electrolyte storage portions 10 and 20 are not particularly limited, but it is preferable to use a material which does not react with the cathode and the anode electrolyte contained in the cathode and anode electrolyte storage portions 10 and 20 desirable.

The cathode electrolyte storage portion 10 is connectable to the cathode electrolyte inlet 41 on one side and the electrolyte outlets 51 and 52 on the cathode and anode. The positive electrode electrolyte reservoir 20 can be connected to the positive electrode electrolyte inlet 42 on one side and the negative electrode and the positive electrode electrolyte outlets 51 and 52 on the other side.

The pump 11 may be connected at one side to the cathode electrolyte reservoir 10 and at the other side to the cathode electrolyte reservoir 10, The pump 21 can be connected to the positive electrode electrolyte reservoir 20 and the other side can be connected to the positive electrode electrolyte inflow port 42. In addition,

In an embodiment of the present invention, the cathode electrolyte stored in the cathode electrolyte storage 10 is transferred to the cathode 32 through the cathode electrolyte inlet 41 through the pump 11, and after the redox reaction is completed, Through the cathode electrolyte outlet 51, to the cathode and anode electrolyte reservoirs 10 and 20. Similarly, the positive electrode electrolyte stored in the positive electrode electrolyte storage part 20 is transferred to the positive electrode 33 through the positive electrode electrolyte inflow port 42 through the pump 21, and after the redox reaction is completed, the positive electrode electrolyte outflow port 52 To the cathode and anode electrolyte reservoirs 10 and 20 through the anode and the cathode.

At this time, a separation membrane 31 may further be provided between the cathode 32 and the anode 33.

Here, the separator 31 transfers the hydrogen ions and blocks the vanadium ions of the negative electrode and the positive electrode electrolyte from moving to the counter electrode.

It is preferable that the separation membrane 31 performing the above-mentioned function uses an ion conductive separator.

The first valve 110 and the second valve 120 serve to discharge the negative electrode and the positive electrode electrolyte from the negative electrode and the positive electrode electrolyte outlets 51 and 52 to at least one of the negative electrode and the positive electrode electrolyte reservoirs 10 and 20 .

At this time, the first valve 110 and the second valve 120 are preferably three-way valves.

The first valve 110 may be connected to the cathode electrolyte outlet 51 and the other may be connected to the cathode electrolyte reservoir 10 and the other electrode may be connected to the cathode electrolyte reservoir 20.

Likewise, the second valve 120 may be connected to the anode electrolyte outlet 52, the other may be connected to the anode electrolyte storage 20, and the other electrode may be connected to the cathode electrolyte reservoir 10, Connectable.

The cathode and the anode electrolyte in the cathode and anode electrolyte outlets 51 and 52 are connected to the cathode and anode electrolyte reservoirs 10 and 20 through the first valve 110 and the second valve 120, The cathode and the anode electrolyte may be stored in the cathode and anode electrolyte reservoirs 10 and 20 in the same amount.

The cathode and anode electrolyte storage units 10 and 20 are provided with graduation measuring units 150 and 151, respectively. Through the measuring units 150 and 151, the user can accurately measure the volume of the negative electrode and the positive electrode electrolyte contained in the negative electrode and positive electrode electrolyte reservoirs 10 and 20.

In addition, the cathode and anode electrolyte reservoirs 10 and 20 may further be provided with volumetric sensors 160 and 161 capable of measuring the volumes of the stored cathode and anode electrolytes.

The first valve 110 and the second valve 120 may be made of a conventional stainless steel or a metal ball. However, it is not preferable when the acid resistance is taken into consideration. The valve may be coated with an acid-resistant polymer, a PTFE (Polytetrafluoroethylene) It is preferably made of a material such as polypropylene (PP), polyvinyl chloride (PVC), polyethylene (PE), and polyvinylidene fluoride (PVDF).

The ion reductant input unit 130 serves to supply the ion reductant to the anode electrolyte storage unit 20.

Therefore, the ion reductant input unit 130 should be configured to be connectable to the anode electrolyte storage unit 20.

Here, it is preferable that the ion reducing agent to be fed into the ion reducing agent input unit 130 is hydrazine monohydrate (N ₂ H ₄ .H ₂ O).

In an embodiment of the present invention, a solution of sulfuric acid in which VOSO ₄ is dissolved, which will be described later, is oxidized to pentavalent vanadium by an electrochemical method, and N ₂ H ₄ .H ₂ O is introduced into the anode electrolyte storage part , It can be estimated that N ₂ , H ₂ O and H ₂ SO ₄ are generated by the following reaction path.

<Reaction path>

Here, a gas valve 131 may be further provided, which is configured to discharge the gas generated by the ion reductant being charged into the anode electrolyte storage part 120 through the gas discharge flow path 132.

The control unit 140 controls whether the first valve 110 and the second valve 120 are opened or closed and the direction in which the electrolyte flows out.

(4-valent vanadium electrolytic solution) flows into the cathode and anode electrolyte reservoirs 10 and 20, and the initial state electrolytic solution flows into the cathode and anode electrolyte inlets 41 and 42 . At this time, pumps 11 and 21, which are connectable to the cathode and anode electrolyte reservoirs 10 and 20, respectively, are further provided so that the initial state electrolytic solution flows through the cathodes and the anode electrolyte inlets 41 and 42 . More specifically, when the pumps 11 and 21 are operated, the negative electrode electrolyte stored in the negative electrode electrolyte reservoir 10 is transferred to the negative electrode 32 through the negative electrode electrolyte inlet 41 through the pump 11. Likewise, the positive electrode electrolyte stored in the positive electrode electrolyte reservoir 20 is transferred to the positive electrode 33 through the positive electrode electrolyte inlet 42 through the pump 21.

Thereafter, the initial state electrolytic solution is oxidized (4 -> 5) / reduction (4 -> 3) at the cathode 32 and the anode 33 of the flow battery.

The initial state electrolytic solution is flowed into the cathode 32 and the anode 33 in the same amount and then charged so that the SOC (State of charge) becomes 100%. The tetravalent electrolytic solution stored in the cathode 32 is reduced to a trivalent electrolytic solution and the tetravalent electrolytic solution stored in the anode 33 is oxidized to a pentavalent electrolytic solution.

Next, the cathodes and the positive electrode electrolytes which are oxidized (tetra-> 5-valent) / reduced (tetra-> trivalent) are ion-isolated and introduced into the cathodic and anodic electrolyte storage portions 10 and 20, Opens the first valve 110 to adjust the flow direction of the electrolytic solution to flow the negative electrode electrolyte discharged from the negative electrode 32 into the negative electrode electrolyte storage part 10 and to open the second valve 120, 33 are flowed into the anode electrolyte storage part 20 by controlling the outflow direction of the electrolyte solution. At this time, ion separation refers to a phenomenon caused by an electrochemical ion separation process, which means an oxidation reaction. That is, the electrolytic solution of the flow battery may mean that the quaternary vanadium (V ⁴⁺ ) is separated into the ^pentavalent vanadium (V ⁵⁺ ) and the electron (e ^- ) by providing the quaternary electrolyte solution and the oxidation reaction occurs at the cathode have. Further, ion separation may include the meaning that electrons ion-separated from the anode migrate to the cathode through the separator.

The cathode and anode electrolyte reservoirs 10 and 20 are respectively provided with measuring units 150 and 151 in the form of scales so that the user can visually check the current flowing through the cathode and the anode electrolyte storage unit 10, and 20, the volume of the negative electrode and the positive electrode electrolyte solution can be accurately measured.

It is noted that the cathode and anode electrolyte reservoirs 10 and 20 may further be provided with volumetric sensors 160 and 161 capable of measuring the volumes of the stored cathode and anode electrolytes.

In this case, the apparatus may further include an agitator capable of agitating the negative electrode and the positive electrode electrolyte stored in the negative electrode and positive electrode electrolyte reservoirs 10 and 20, respectively.

Next, the ionic reducing agent is injected into the positive electrode electrolyte storage part 20.

More specifically, the anode electrolyte storage 20 stores a pentavalent electrolyte, in which an ionic reducing agent is added to reduce the pentavalent electrolytic solution to a tetravalent electrolyte.

Here, the ionic reducing agent is preferably hydrazine monohydrate.

When the hydrazine monohydrate is charged into the anode electrolyte storage part 20, the control part 140 opens the gas valve 131 and discharges the generated gas through the gas discharge path 132 Can be discharged.

At this time, N ₂ , H ₂ O and H ₂ SO ₄ are generated in the generated gas, and these substances are not substances that cause side reactions when the cells are reacted, so that there is no side effect.

In addition, when the pentavalent electrolytic solution is reduced to a tetravalent electrolytic solution, it does not undergo a separate cell reaction, thereby preventing the physical properties of the battery material from being weakened.

It is preferable that the electrolytic cell further comprises an agitating device which is charged with an ionic reducing agent to reduce the pentavalent electrolytic solution stored in the anode electrolytic solution storage part 20 and can be stirred to be uniformly mixed.

Next, when trivalent and tetravalent electrolytic solutions stored in the cathode and anode electrolyte storage portions 10 and 20 are introduced into the cathode and anode electrolyte inlets 41 and 42, respectively, and the redox reaction is completed, the cathode and the anode electrolyte The control unit 140 opens the first valve 110 to store the negative electrode electrolyte discharged from the negative electrode 32 into the negative electrode electrolyte storage unit 10 or 20, The second valve 120 is opened to regulate the flow direction of the electrolyte so that the anode electrolyte discharged from the anode 33 flows into the cathode electrolyte storage part 10, .

Similarly, the control unit 140 opens the first valve 110 to regulate the flow direction of the electrolyte so that the negative electrode electrolyte discharged from the negative electrode 32 flows into the positive electrode electrolyte storage unit 20, 120 are opened to control the outflow direction of the electrolyte so that the anode electrolyte discharged from the anode 33 flows into the anode electrolyte storage 20.

When the above process is repeatedly performed, the negative electrode electrolyte stored in the negative electrode electrolyte reservoir 10 and the positive electrode electrolyte stored in the positive electrode electrolyte reservoir 20 are uniformly mixed.

At this time, the first valve 110 and the second valve 120 are preferably three-way valves.

More specifically, trivalent and tetravalent electrolytic solutions are stored in the cathodic and the cathodic electrolytic solution storage parts 10 and 20. At this time, when the solution is homogeneously mixed using an agitator, a 3.5-valent electrolytic solution is prepared.

Therefore, according to an embodiment of the present invention, the cathode and anode electrolyte reservoirs 10 and 20 respectively store a cathode and a cathode electrolyte having an average oxidation number of vanadium ions of V ^3.5+ .

Then, the negative electrode and the positive electrode electrolytic solution are equally distributed to the negative electrode and the positive electrode electrolyte reservoirs 10 and 20, respectively.

According to one embodiment of the present invention, the initial state electrolytic solution is oxidized / reduced and separated from the cathode and the anode of the flow battery, and then flows into the cathode and anode electrolyte reservoir, and then the ion- By the addition, the pentavalent electrolytic solution can be relatively easily reduced to the tetravalent electrolytic solution, and the tetravalent and trivalent electrolytic solutions are uniformly mixed to form the 3.5-valent electrolytic solution, and the 3.5-valent electrolytic solution formed by the mixing is supplied to both the cathode and the anode It is possible to improve the utilization efficiency of the negative electrode and the positive electrode electrolyte of the flow battery.

<Electrolyte Mixing Method of Flow Battery>

3 is a flowchart illustrating a method of mixing an electrolyte of a flow battery according to an embodiment of the present invention.

The electrolyte solution mixing method of the flow battery comprises the steps of: (a) introducing an initial state electrolyte solution into a cathode and a cathode electrolyte inlet; (b) oxidizing / reducing the initial state electrolyte at the cathode and the anode of the flow battery; (c) introducing the oxidized / reduced anode and anode electrolyte into the cathode and anode electrolyte reservoir by ion separation; And (d) an ionic reducing agent is introduced into the anode electrolyte storage part.

In addition, a method for mixing an electrolyte of a flow battery according to an embodiment of the present invention includes the steps of: (e) mixing the anode electrolyte stored in the anode electrolyte reservoir with the anode electrolyte stored in the anode electrolyte reservoir; As shown in FIG.

In the step (a), the initial state electrolytic solution flows into the cathode and the anode electrolyte inlets 11 and 21, respectively.

The initial state electrolytic solution flows into the cathode and anode electrolyte inlets 41 and 42, respectively. At this time, pumps 11 and 21, which are connectable to the cathode and anode electrolyte reservoirs 10 and 20, respectively, are further provided so that the initial state electrolytic solution flows through the cathodes and the anode electrolyte inlets 41 and 42 . More specifically, when the pumps 11 and 21 are operated, the negative electrode electrolyte stored in the negative electrode electrolyte reservoir 10 is transferred to the negative electrode 32 through the negative electrode electrolyte inflow port 41 through the pump 11. Likewise, the positive electrode electrolyte stored in the positive electrode electrolyte reservoir 20 is transferred to the positive electrode 33 through the positive electrode electrolyte inlet 42 through the pump 21.

Here, the step (a) may further include a step in which the initial state electrolytic solution is introduced into the cathode and anode electrolyte storage portions 10 and 20.

At this time, the initial state electrolytic solution flows into the cathode and anode electrolyte storage portions 10 and 20 in the same amount.

Further, a step of stirring the initial state electrolytic solution stored in the cathode and anode electrolyte storage parts 10 and 20 so that the initial state electrolytic solution can be uniformly mixed may be further added.

(b) is a step in which the initial state electrolytic solution is oxidized / reduced at the cathode 32 and the anode 33 of the flow battery.

When the initial state electrolytic solution is charged to the cathode 32 and the anode 33 in the same amount and then charged so that the state of charge (SOC) becomes 100%, the tetravalent electrolyte stored in the cathode 32 becomes a trivalent electrolytic solution And the tetravalent electrolytic solution stored in the anode 33 is oxidized into a pentavalent electrolytic solution.

In the step (c), the oxidized / reduced cathode and the anode electrolyte are ion-separated and introduced into the cathode and anode electrolyte reservoirs 10 and 20.

The cathode and the anode electrolytic solution which are oxidized (tetra-> 5-valent) / reduced (tetra-> 3) are separated and introduced into the cathode and anode electrolyte reservoirs 10 and 20, The first valve 110 is opened to adjust the outflow direction of the electrolytic solution to flow the negative electrode electrolyte discharged from the negative electrode 32 into the negative electrode electrolyte storage part 10 and to open the second valve 120 to open the positive electrode 33, So that the anode electrolyte solution flowing out from the cathode electrolyte solution reservoir 20 flows into the anode electrolyte reservoir 20.

The cathode and anode electrolyte reservoirs 10 and 20 are respectively provided with measuring units 150 and 151 in the form of scales so that the user can visually check the current flowing through the cathode and the anode electrolyte storage unit 10, and 20, the volume of the negative electrode and the positive electrode electrolyte solution can be accurately measured.

It is noted that the cathode and anode electrolyte reservoirs 10 and 20 may further be provided with volumetric sensors 160 and 161 capable of measuring the volumes of the stored cathode and anode electrolytes.

(d) is a step in which the ionic reducing agent is charged into the cathode electrolyte storage part 20. [

In the anode electrolyte storage part 20, a pentavalent electrolytic solution is stored. At this time, an ionic reducing agent is added to reduce the pentavalent electrolytic solution to tetravalent electrolytic solution.

When the hydrazine monohydrate is charged into the anode electrolyte storage part 20, the control part 140 opens the gas valve 131 and discharges the generated gas through the gas discharge path 132 Can be discharged.

It is preferable that the electrolytic cell further comprises an agitating device which is charged with an ionic reducing agent to reduce the pentavalent electrolytic solution stored in the anode electrolytic solution storage part 20 and can be stirred to be uniformly mixed.

In the step (e), the negative electrode electrolyte stored in the negative electrode electrolyte reservoir 10 and the positive electrode electrolyte stored in the positive electrode electrolyte reservoir 20 are mixed.

When the trivalent and tetravalent electrolytic solutions stored in the cathode and anode electrolyte reservoirs 10 and 20 are introduced into the cathode and anode electrolyte inlets 41 and 42 respectively and the redox reaction is completed, The control unit 140 opens the first valve 110 to discharge the negative electrode electrolyte discharged from the negative electrode 32 to the negative electrode electrolyte storage unit 10 or 20, And the second valve 120 is opened to adjust the flow direction of the electrolyte so that the anode electrolyte discharged from the anode 33 flows into the cathode electrolyte storage part 10.

Similarly, the control unit 140 opens the first valve 110 to regulate the flow direction of the electrolyte so that the negative electrode electrolyte discharged from the negative electrode 32 flows into the positive electrode electrolyte storage unit 20, 120 are opened to control the outflow direction of the electrolyte so that the anode electrolyte discharged from the anode 33 flows into the anode electrolyte storage 20.

When the above process is repeatedly performed, the negative electrode electrolyte stored in the negative electrode electrolyte reservoir 10 and the positive electrode electrolyte stored in the positive electrode electrolyte reservoir 20 are uniformly mixed.

The reason for this is to remove the difference in the concentration of both electrolytes which adversely affects the performance of the battery because the capacity of the battery is conserved because it is expected that the hydrazine monohydrate will cause volume increase and concentration change when a small amount of hydrazine monohydrate is added.

<Experimental Example 1>

1 mol VOSO ₄ dissolved in 2 molar sulfuric acid solution was oxidized by an electrochemical method into a pentavalent vanadium solution and then 50 ml was taken out and charged into a container equipped with a condenser and N ₂ H ₄ .H ₂ O in 0.1 ml increments at intervals of 30 seconds.

In summary, a 2 molar sulfuric acid solution in which 1 molar VOSO ₄ is dissolved is oxidized to a pentavalent vanadium solution, then N ₂ H ₄ .H ₂ O is added to the oxidized pentavalent vanadium solution according to one embodiment of the present invention Respectively.

<Experimental Example 2>

3 molar sulfuric acid solution was used as the catalyst.

In summary, a 3 molar sulfuric acid solution in which 1 molar VOSO ₄ is dissolved is oxidized to a pentavalent vanadium solution, then N ₂ H ₄ .H ₂ O is added to the oxidized pentavalent vanadium solution according to one embodiment of the present invention Respectively.

<Experimental Example 3>

2 moles of VOSO ₄ and N ₂ H ₄ .H ₂ O of 16 times.

In summary, a 3 molar sulfuric acid solution in which 2 molar VOSO ₄ is dissolved is oxidized to a pentavalent vanadium solution, then N ₂ H ₄ .H ₂ O is added to the oxidized pentavalent vanadium solution according to one embodiment of the present invention Respectively.

<Discussion of results>

FIG. 4 is a graph showing the results of oxidation of a sulfuric acid solution in which VOSO ₄ is dissolved according to an electrolytic solution mixing method of a flow battery according to an embodiment of the present invention by electrochemical oxidation to a pentavalent vanadium solution and then adding hydrazine monohydrate (N ₂ H ₄ .H ₂ O) was injected into the electrolyte solution to change the state of the tetravalent vanadium solution.

Considering the results of the above experiments,

In Experimental Example 1, a 2 molar sulfuric acid solution in which 1 mol of VOSO ₄ was dissolved was oxidized to a pentavalent vanadium solution by an electrochemical method, and the color of the vanadium solution was observed to be yellow. Then, N ₂ H ₄ .H ₂ O was injected in 0.1ml increments every 30 seconds, and the color of the vanadium solution was blue.

In Experimental Example 2, a 3 molar sulfuric acid solution in which 1 mol of VOSO ₄ was dissolved was oxidized to a pentavalent vanadium solution by an electrochemical method, and the color of the vanadium solution was observed to be dark yellow. Then, N ₂ H ₄ .H ₂ O was injected in 0.1ml increments every 30 seconds, and the color of the vanadium solution was observed to be blue.

In Experimental Example 3, a 3 molar sulfuric acid solution in which 2 molar VOSO ₄ was dissolved was oxidized to a pentavalent vanadium solution by an electrochemical method, and the color of the vanadium solution was observed to be considerably dark yellow. Then, 0.1 ml of N ₂ H ₄ .H ₂ O was added 16 times at intervals of 30 seconds, and the color of the vanadium solution was observed to be blue

The reason for this is as follows.

In Experimental Example 1, Experimental Example 2 and Experimental Example 3, N ₂ H ₄ .H ₂ O was added to the sulfuric acid solution in which VOSO ₄ was dissolved, and the color of the solution was observed. As a result, It can be seen that the pentavalent vanadium solution was reduced to the tetravalent vanadium solution due to N ₂ H ₄ .H ₂ O by changing to blue.

Comparing Experimental Example 1 with Experimental Example 2, when reducing the pentavalent vanadium solution to the tetravalent vanadium solution, the number of moles of the sulfuric acid solution was changed to 2 mol and 3 mol, and then the pentavalent vanadium solution was reduced to the tetravalent vanadium solution when up to the amount of N ₂ H ₄ .H ₂ O in spite of that (the color of the vanadium solution until a change in blue) N ₂ H ₄ .H ₂ O After the input, different from the number of moles of the sulfuric acid solution, in And it was found that the molar amount of sulfuric acid solution and the input amount of N ₂ H ₄ .H ₂ O are not related to each other.

In comparison between Experimental Example 2 and Experimental Example 3, when reducing the pentavalent vanadium solution to the tetravalent vanadium solution, the number of moles of VOSO ₄ was changed to 1 mol and 2 mol, and then the pentavalent vanadium solution was converted into the tetravalent vanadium solution As a result of the addition of N ₂ H ₄ .H ₂ O until the reduction (the color of the vanadium solution changed to blue), 1 mole of VOSO ₄ was added 8 times and 2 moles of VOSO ₄ was added 16 times . As a result, the amount of N ₂ H ₄ .H ₂ O was increased as the mole number of VOSO ₄ increased.

Therefore, it is considered that the pentavalent vanadium solution can be reduced to the tetravalent vanadium solution by determining the amount of N ₂ H ₄ .H ₂ O to be added in consideration of the mole number of VOSO ₄ .

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

10: cathode electrolytic solution storage part 11: pump
20: cathode electrolytic solution storage part 21: pump
31: Membrane
32: cathode 33: anode
41: cathode electrolyte inlet 42: anode electrolyte inlet
51: cathode electrolyte outlet 52: anode electrolyte outlet
100: electrolyte regeneration module
110: first valve 120: second valve
130: ion reductant input unit
131: gas valve 132: gas discharge passage
140:
150, 151:
160, 161: Volumetric sensor

Claims (21)

1. An electrolyte mixing module applicable to a flow battery,
A negative electrode and a positive electrode electrolyte reservoir configured to store at least one of a negative electrode and a positive electrode electrolyte;
An ion reductant input unit for supplying an ion reductant to the anode electrolyte storage unit;
A first valve and a second valve for discharging the negative electrode and the positive electrode electrolyte solution to at least one of the negative electrode and the positive electrode electrolyte reservoir in the negative electrode and the positive electrode electrolyte outlet; And
The anode valve is opened to allow the cathode electrolyte discharged from the cathode to flow into the anode electrolyte storage or cathode electrolyte storage and the cathode electrolyte discharged from the cathode is opened by opening the second valve to the anode electrolyte storage or catholyte storage And a controller for controlling whether the first valve and the second valve are open or closed and the flow direction of the electrolyte to flow into the storage part,
Electrolyte mixing module.
The method according to claim 1,
Wherein the negative electrode and the positive electrode electrolyte are oxidized / reduced respectively at a cathode and an anode of the flow battery,
Electrolyte mixing module.
The method according to claim 1,
Wherein the first valve and the second valve are three-way valves.
Electrolyte mixing module.
delete delete delete The method according to claim 1,
The positive electrode electrolyte reservoir is further provided with a gas valve,
Wherein the gas valve is configured to discharge gas generated when the ion reducing agent is introduced.
Electrolyte mixing module.
The method according to claim 1,
Wherein the negative electrode and the positive electrode electrolyte storage portion are provided with a graduation-type measuring portion for measuring the volume of the stored negative and positive electrode electrolytes,
Electrolyte mixing module.
The method according to claim 1,
Wherein the negative electrode and the positive electrode electrolyte storage portion are further provided with a volumetric sensor capable of measuring the volumes of the stored negative and positive electrode electrolytes.
Electrolyte mixing module.
The method according to claim 1,
The electrolytic solution mixing module includes:
And a pump capable of being connected to the cathode electrolyte solution reservoir, one side of which is connectable to the cathode electrolyte reservoir, the other side of which is connectable to the anode electrolyte solution inlet, and the other side of which is connectable to the anode electrolyte solution reservoir.
Electrolyte mixing module.
The method according to claim 1,
Wherein the electrolyte solution mixing module includes a separator between the cathode and the anode.
Electrolyte mixing module.
The method according to claim 1,
The electrolytic solution mixing module includes:
Further comprising an agitator capable of agitating the negative electrode and the positive electrode electrolyte stored in the negative electrode and positive electrode electrolyte reservoir, respectively,
Electrolyte mixing module.
13. The method of claim 12,
The stirring device
Characterized in that it is any one of an impeller, an agitator and a magnetic stirrer.
Electrolyte mixing module.
The method according to claim 1,
Characterized in that the ionic reducing agent is hydrazine monohydrate (N ₂ H ₄ .H ₂ O).
Electrolyte mixing module.
The method according to claim 1,
Wherein the flow battery is a vanadium redox flow battery.
Electrolyte mixing module.
1. A method for mixing an electrolyte in a flow battery,
(a) an initial state electrolyte is introduced into the cathode and anode electrolyte inlets, respectively;
(b) oxidizing / reducing the initial state electrolyte at the cathode and the anode of the flow battery;
(c-1) the control unit opens the first valve to cause the oxidized cathode electrolyte discharged from the cathode to flow into the cathode electrolyte storage unit, open the second valve, and flow the anode electrolyte reduced in the anode into the anode electrolyte lower reservoir ;
(c-2) the control unit opens the first valve to cause the oxidized cathode electrolyte discharged from the cathode to flow into the cathode electrolyte storage unit, open the second valve, and the anode electrolyte reduced in the cathode flows into the cathode electrolyte bottom ;
(d) an ionic reducing agent is charged into the anode electrolyte storage part; And
(e) repeating the steps (c-1) and (c-2) to repeatedly mix the cathode electrolyte stored in the cathode electrolyte reservoir and the anode electrolyte stored in the cathode electrolyte reservoir ;
Flow electrolyte.
17. The method of claim 16,
In the step (a)
And an initial state electrolytic solution is introduced into the cathode and anode electrolyte reservoirs.
Flow electrolyte.
17. The method of claim 16,
In the steps (a) and (d)
And stirring the negative and positive electrode electrolytes stored in the negative and positive electrode electrolyte reservoirs, respectively.
Flow electrolyte.
17. The method of claim 16,
In the step (d)
And discharging gas generated when the ionic reducing agent is introduced.
Flow electrolyte.
delete 17. The method of claim 16,
Wherein the flow battery is a vanadium redox flow battery.
Flow electrolyte.

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