KR101716391B1 - Redox flow battery - Google Patents

Abstract

One embodiment of the present invention is to provide a redox flow cell which further includes a solar cell in a redox flow cell to maximize energy efficiency. The redox flow cell according to an embodiment of the present invention includes: a cell module for charging and discharging an anode and a cathode disposed on both sides of a separation membrane in a frame and separating the anode and the cathode from each other; an anode electrolyte tank connected to a gap between the separation membrane and the anode using an anode tube to supply the anode electrolyte, and storing the anode electrolyte discharged from the anode tube; and a cathode electrolyte tank connected to a gap between the separation membrane and the cathode using a cathode tube to supply the cathode electrolyte, and storing the cathode electrolyte discharged from the cathode tube. At least a part of the cathode is formed of a solar cell.

Description

Redox Flow Battery {REDOX FLOW BATTERY}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a redox flow cell, and more particularly to a redox flow cell having a photovoltaic cell.

BACKGROUND ART Redox flow batteries are known to perform charging and discharging operations by oxidation and reduction reactions of circulating electrolytes. The redox flow cell is excellent in life characteristics and storage characteristics, and can be modularized, making it possible to easily increase the energy density.

However, the redox flow battery requires additional energy for driving the pump because the electrolyte circulation is performed by the pump. In addition, current consumption is caused by various resistances generated when the electrolyte circulates in various components. That is, the energy efficiency is lowered.

One embodiment of the present invention is to provide a redox flow cell that further includes a solar cell in a redox flow cell to maximize energy efficiency.

The redox flow cell according to an embodiment of the present invention includes a battery module for charging and discharging the anode electrode and the cathode electrode disposed on both sides of a separation membrane in a frame, and an anode electrode for supplying an anode electrolyte between the separation membrane and the anode electrode. An anode electrolyte tank for storing an anode electrolyte connected and discharged through a tube and a cathode electrolyte tank for storing a cathode electrolyte solution connected to and discharged from the cathode tube to supply a cathode electrolyte between the separation membrane and the cathode electrode, At least a part of which is formed of a solar cell.

In the battery module, the anode electrode and the cathode electrode may be electrically connected to an external power source or a load through a charge / discharge line.

At least one of the anode tube and the cathode tube may have a coating layer formed of a nanomaterial on the inner surface.

The coating layer may be formed of grapheme or carbon nanotube.

At least one of the anode tube and the cathode tube is low at the inlet side of the anode electrolyte or cathode electrolyte and can produce a high voltage difference at the outlet side.

The frame may have a transmission window for transmitting sunlight to a portion facing the photovoltaic cell.

The photovoltaic cell may include a TiO ₂ film formed on a photo electrode.

The anode electrolyte may include zinc, and the cathode electrolyte may include iodine.

The anode electrode is charged (→) and discharged (←) with Zn ^{2 +} + 2e ^- ↔ Zn and is connected to the photovoltaic cell through a first electron injection line to charge Zn ^{2 +} + 2e ^- → Zn And may be further charged into the anode electrolyte by receiving the collected electrons.

The cathode electrode side is charged (→) and discharged (←) by 3I ^- ↔ I ₃ ^- + 2e ^- and connected to the anode electrode side by a second electron injection line at the time of discharge to form I ₃ ^- + 2e ^- → 3I ^-, and electrons can be replenished to the cathode electrolyte solution.

The anode tube includes an anode electrolyte supply line through which the anode electrolyte of the anode electrolyte tank is supplied to the anode electrode via a first pump and an anode electrolyte recovery line for withdrawing the anode electrolyte from the anode electrode side to the anode electrolyte tank And the charge / discharge lines on both sides of the power source or the load can be electrically connected by winding the anode auxiliary line on the anode electrolyte recovery line.

The anode electrolyte recovery line may be wound into an anode addition line, and an additional voltage may be applied to the anode addition line.

The cathode tube includes a cathode electrolytic solution supply line for supplying a cathode electrolytic solution of the cathode electrolytic solution tank to the cathode side through a second pump and a cathode electrolytic solution collecting line for collecting the cathode electrolytic solution from the cathode side to the cathode electrolytic solution tank And the charge / discharge lines on both sides of the power source or the load can be electrically connected by winding the cathode auxiliary line on the cathode electrolyte recovery line.

The cathode electrolyte recovery line may be wound in a cathode addition line, and a separate voltage may be applied to the cathode addition line.

As described above, according to one embodiment of the present invention, a part of the cathode electrode of the redox flow cell is formed of a solar cell, and in addition to the charging and discharging action by the cathode electrode and the anode electrode, Energy efficiency can be maximized.

In this embodiment, a coating layer of a nanomaterial is formed on the inner surface of at least one of the anode tube and the cathode tube, and a voltage is additionally generated in the flow of the anode electrolyte or the cathode electrolyte, thereby minimizing energy loss due to the flow resistance of the electrolyte can do. That is, the efficiency of the redox flow cell can be further improved.

Also, in this embodiment, since the anode auxiliary line or the anode additional line is wound around the anode electrolyte recovery line and electrically connected thereto, the resistance due to the tube friction of the flowing anode electrolyte can be further reduced. That is, the efficiency of the redox flow cell can be further improved.

Further, in this embodiment, since the cathode auxiliary line or the cathode additional line is wound around the cathode electrolyte recovery line and electrically connected thereto, the resistance due to the tube friction of the cathode electrolyte flowing through addition of the electromotive force can be further reduced. That is, the efficiency of the redox flow cell can be further improved.

1 is a configuration diagram of a redox flow cell according to an embodiment of the present invention.
2 is a cross-sectional view of an anode tube or a cathode tube.
3 is a graph showing voltage and energy density capacities due to charging of a conventional redox flow cell.
4 is a graph showing voltage and energy density capacities due to charging of a solar cell in a redox flow cell according to an embodiment of the present invention.
5 is a graph showing voltage and energy density capacities due to discharge of a general redox flow cell.
6 is a graph showing voltage and energy density capacities due to discharge of a solar cell in a redox flow cell according to an embodiment of the present invention.
FIG. 7 is a graph illustrating the initial charge and discharge curves of a conventional redox flow cell and the charge and discharge curves when a voltage is generated due to the flow of the electrolyte in the anode and cathode tubes of the redox flow cell according to an embodiment of the present invention. To compare the voltage and the energy density capacity.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

1 is a configuration diagram of a redox flow cell according to an embodiment of the present invention. 1, a redox flow cell according to an embodiment of the present invention includes a battery module 10 for charging and discharging, an anode electrolyte tank 20 for containing an anode electrolyte, and a cathode electrolyte tank 30 ).

The battery module 10 is configured to charge and discharge the anode electrode 11 and the cathode electrode 12 on both sides of the separation membrane 13 by disposing them in the frame 14. In this embodiment, one frame 14 is provided with a separation membrane 13, an anode electrode 11, and a cathode electrode 12, respectively.

The battery module 10 is electrically connected to the external power source or the load 40 through the charge and discharge lines L11 and L12 to the anode electrode 11 and the cathode electrode 12. [ The battery module 10 can be charged from the external power source 40 or discharged to the load 40 through the charge / discharge lines L11 and L12.

Although not shown, the battery module may be formed by connecting a plurality of frames including a separation membrane, an anode electrode, and a cathode electrode in series. In this case, the battery module has a current collecting plate at its outermost portion, and is connected to the current collecting plate by a pre-charge line, so that it can be charged from a power source or discharged to a load.

The anode electrode 11 is disposed on one side of the frame 14 and is exposed to the anode electrolyte on one side and has a Zn metal 111 on the exposed surface to react with the anode electrolyte. For example, the anode electrolyte may be a zinc electrolytic solution containing zinc.

The cathode electrode 12 may be disposed on the other side of the frame 14 facing the anode electrode 11 and may be exposed to the cathode electrolyte solution on one side to react with the cathode electrolyte. For example, the cathode electrolytic solution may be an iodine electrolytic solution containing iodine.

At least a portion of the cathode electrode 12 is formed of a solar cell 121. The solar cell 121 is a dye sensitized solar cell. The cathode electrolytic solution is used as an electrolyte solution for the cathode electrode 12 and the solar cell 121, thereby integrating the solar cell 121 as an energy generating system and the energy storage system (cathode electrode side).

That is, a zinc-based zinc electrolytic solution is circulated on the anode electrode 11 side, and an iodine-based iodine electrolytic solution circulates on the cathode electrode 12 side. Therefore, an electromotive force (for example, 1.2986 V) due to the oxidation / reduction reaction of zinc and iodine can be output.

The oxidation / reduction reaction is as follows.

Zn ^{2 +} + 3I ^- ↔ Zn + I ₃ ^- (E ₀ = 1.2986 V) (→ charge / ← discharge)

The separation membrane 13 is disposed between the anode electrode 11 and the cathode electrode 12 opposed to each other in the frame 14 to allow movement of ions during charge and discharge operations in an oxidation / reduction reaction.

For example, if ZnI ₂ electrolytes are used, the energy density can be higher than the redox flow cells based on conventional vanadium electrolytes. That is, when 7 moles of ZnI ₂ electrolyte is dissolved in water, the theoretical energy density that can be obtained through the oxidation / reduction reaction is about 322 Wh / L. Which is higher than 220Wh / L of LiFePO ₄ , the anode material of lithium ion batteries.

The anode electrolyte tank 20 is connected to the anode tube 21 (211, 212) to supply the anode electrolyte between the separation membrane 13 and the anode electrode 11 and to discharge it after the oxidation / reduction reaction, And the anode electrolyte discharged between the electrodes 11 is stored.

The anode tube 21 includes an anode electrolyte supply line 211 and an anode electrolyte recovery line 212. The anode electrolyte supply line 211 supplies the anode electrolyte of the anode electrolyte tank 20 to the anode electrode 11 side, that is, between the anode electrode 11 and the separation membrane 13 via the first pump P1.

The anode electrolyte recovery line 212 recovers the anode electrolyte from the anode electrode 11 side, that is, between the anode electrode 11 and the separation membrane 13 to the anode electrolyte tank 20. The anode electrolytic solution generates an electric current by the oxidation / reduction reaction at the anode electrode 11 side and is stored in the anode electrolyte tank 20.

The cathode electrolytic solution tank 30 is connected to the cathode tubes 31 311 and 312 to supply the cathode electrolytic solution between the separation membrane 13 and the cathode electrode 12 and to discharge the cathode electrolytic solution after the oxidation / reduction reaction, And stores the cathode electrolyte discharged between the electrodes 12.

The cathode tube 31 includes a cathode electrolyte supply line 311 and a cathode electrolyte recovery line 312. The cathode electrolytic solution supply line 311 supplies the cathode electrolytic solution of the cathode electrolytic solution tank 30 to the cathode electrode 12 side, that is, between the cathode electrode 12 and the separator 13 via the second pump P2.

The cathode electrolyte recovery line 312 recovers the cathode electrolyte solution to the cathode electrolyte solution tank 30 at the cathode electrode 12 side, that is, between the cathode electrode 12 and the separation membrane 13. The cathode electrolytic solution generates a current in the redox reaction on the cathode electrode 12 side and is stored in the cathode electrolytic solution tank 30.

2 is a cross-sectional view of an anode tube or a cathode tube. Referring to FIG. 2, at least one of the anode tube 21 and the cathode tube 31 includes a coating layer 22, 32 formed by coating a nanomaterial having a large surface charge on the inner surface.

The coating layers 22 and 32 are formed of grapheme or carbon nanotube. The coating layers 22 and 23 of the nanomaterial generate a charge concentration gradient by dragging the surface due to the surface adhesion force when the electrolyte fills the inner surfaces of the anode and cathode tubes 21 and 31 with electrolyte.

The coating layers 22 and 23 generate a voltage corresponding to the concentration gradient of the electrolyte solution, thereby compensating for the resistance loss due to the tube friction on the inner surface of the tube. At least one of the anode tube 21 and the cathode tube 31 is low at the inlet side of the anode electrolyte or cathode electrolyte and generates a high voltage difference at the outlet side to compensate for resistance loss due to tube friction.

Referring again to FIG. 1, the frame 14 has a transmission window 141 for transmitting sunlight at a portion facing the solar cell 121. The solar cell 121 includes a TiO ₂ film 142 formed on the photoelectrode. Since the TiO ₂ film 142 is disposed toward the transmission window 141, the solar cell 121 can generate current by sunlight.

On the other hand, the anode electrode 11 side is connected to the solar cell 121 through the first electron injection line E1, and upon charging, receives the collected electrons and is further charged into the anode electrolyte. That is, the anode electrode 11 side is charged (→) and discharged (←) to Zn ^{2 +} + 2e ^- ↔ Zn. At the time of charging, the solar cell 121 is connected to the first electron injection line E1 to receive the collected electrons as Zn ^{2 +} + 2e ^- → Zn.

The cathode electrode 12 side is connected to the anode electrode 11 through a second electron injection line E2 so that electrons are injected at the time of discharge to replenish electrons in the cathode electrolyte. That is, the side of the cathode electrode 12 functions as a charge (→) and a discharge (←) with 3I ^- ↔ I ₃ ^- + 2e ^- . During discharging, is connected to the second electron injection line (E2) on the side of the anode electrode ^{_{(11), I 3 - +}} 2e - → 3I - receive injection of electrons, such as.

The charge / discharge lines L11 and L12 are connected to the anode auxiliary lines AL11 and AL12 at both sides of the power source or the load 40 and the anode auxiliary lines AL11 and AL12 are wound around the anode electrolyte recovery line 212 , And is electrically connected to the anode electrolyte recovery line (212). The anode electrolyte recovery line 212 is wound around the anode addition line AL1 and an additional voltage V1 is applied to the anode addition line AL1.

Since the anode auxiliary lines AL11 and AL12 or the anode addition line AL1 are wound around the anode electrolyte recovery line 212 and are electrically connected to each other, an anode electrolytic solution The resistance due to friction can be reduced. That is, the energy loss due to the flow resistance of the anode electrolyte recovery line 212 is minimized, so that the energy efficiency of the entire system can be improved.

The charge / discharge lines L11 and L12 on both sides of the power source or the load 40 are connected to the cathode auxiliary lines CL11 and CL12 and the cathode auxiliary lines CL11 and CL12 are wound on the cathode electrolyte recovery line 312 And is electrically connected to the cathode electrolyte recovery line 312. The cathode electrolyte recovery line 312 is wound around the cathode addition line CL1, and a separate voltage V2 is applied to the cathode addition line CL1.

Since the cathode auxiliary lines CL11 and CL12 or the cathode addition line CL1 are wound and electrically connected to the cathode electrolyte recovery line 312, an electromotive force is added to the cathode electrolyte solution recovery line The energy loss due to the flow resistance of the cathode electrolyte recovery line 312 can be minimized and the energy efficiency of the entire system can be improved.

FIG. 3 is a graph showing voltage and energy density capacities due to charging of a general redox flow cell, and FIG. 4 is a graph showing voltage and energy density due to charging of a photovoltaic cell in a redox flow cell according to an embodiment of the present invention. Fig.

Referring to FIG. 3, when the redox flow cell is charged by the redox reaction between the anode electrode side and the cathode electrode side in a state where the general or solar cell is not operated, the relationship between the voltage due to charging and the energy density capacity It appears as an upward parabolic curve C11.

4, when the photovoltaic cell 121 starts to charge in the redox flow cell according to an embodiment of the present invention, when the voltage is lower than the difference voltage? V1 corresponding to the charging of the solar cell 121 In the upward shifted state, the relationship between the voltage and the energy density capacity as shown in Fig. 3 is represented by the right upward parabola C12.

FIG. 5 is a graph showing a voltage and an energy density capacity due to discharge of a general redox flow cell, and FIG. 6 is a graph showing a relationship between a voltage and an energy density due to discharge of the photovoltaic cell in the redox flow cell according to an embodiment of the present invention Fig.

5, when the redox flow cell is discharged by the redox reaction between the anode electrode side and the cathode electrode side in a state where the general or solar cell is not operated, the relationship between the voltage due to the discharge and the energy density capacity And a downward parabola (C21).

Referring to FIG. 6, when the photovoltaic cell 121 starts to charge in the redox flow cell according to an embodiment of the present invention, when the voltage is lower than the difference voltage V2 corresponding to the charging of the solar cell 121 In the upward shifted state, the relationship between the voltage and the energy density capacity as shown in Fig. 5 is expressed by the rightward parabola C22.

FIG. 7 is a graph illustrating the charge and discharge curves of a conventional redox flow cell (or of an embodiment of the present invention) and the voltage generated by the flow of the electrolyte in the anode and cathode tubes of the redox flow cell according to one embodiment of the present invention Lt; RTI ID = 0.0 > charge / discharge < / RTI > curves.

That is, in the case where the coating layers 22 and 32 are formed by coating the inner surface of the anode tube 21 and the cathode tube 31 with nanomaterials having a large surface charge (redox flow cell of one embodiment of the present invention) And the energy density capacity form the right upward parabola C31 and the right downward parabola C32, respectively.

The relation between voltage and energy density capacity due to charging and discharging is shown by the right upward parabola (C41) and the right downward parabola (C42) when the coating layer is not formed on the anode tube and the cathode tube .

The upper right parabola C31 and the right lower parabola C32 in the case of forming the coating layers 22 and 32 as in the embodiment of the present invention are formed in a case where a coating layer is not formed in a general redox flow cell Shifted upward by the difference voltage DELTA V3 corresponding to the charging of the voltage induced by the coating layers 22 and 32 in the right upper parabola C41 and the right lower parabola C42 in the case of the initial charging and discharging of the embodiment to be.

That is, one embodiment of the present invention in which the coating layers 22 and 32 are formed on the anode tube 21 and the cathode tube 31 generates a voltage induced by the flow of the anode electrolyte and the cathode electrolyte, The energy efficiency of the entire system can be further improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And it goes without saying that the invention belongs to the scope of the invention.

10: Battery module 11: Anode electrode
12: cathode electrode 13: separator
14: frame 20: anode electrolyte tank
21: anode tube 22, 32: coating layer
30: cathode electrolyte tank 31: cathode tube
40: Power source or load 111: Zn metal
141: transmission window 142: TiO ₂ film
121: Photovoltaic cell 211: Anode electrolyte supply line
212: anode electrolyte recovery line 311: cathode electrolyte supply line
312: cathode electrolytic recovery line AL1: anode addition line
AL11, AL12: anode auxiliary line CL1: cathode addition line
CL11, CL12: cathode auxiliary lines C21, C22, C32, C42: right downward parabola
C11, C12, C31, C41: right upward parabola E1: first electron injection line
E2: second electron injection line L11, L12: charge / discharge line
P1, P2: first and second pumps V1, V2: voltage
? V1,? V2,? V3: Difference voltage

Claims (14)

A battery module for charging and discharging the anode electrode and the cathode electrode by disposing them on both sides of the separation membrane inside the frame;
An anode electrolyte tank connected to the anode tube to supply an anode electrolyte between the separator and the anode electrode and storing the discharged anode electrolyte; And
A cathode electrolytic solution tank connected to the cathode tube to supply the cathode electrolytic solution between the separator and the cathode electrode,
/ RTI >
The cathode electrode
At least a part of which is formed of a solar cell,
In the battery module, the anode electrode and the cathode electrode
Discharging line electrically connected to an external power source or load,
Wherein the charge / discharge line on both sides of the power source or the load,
An anode auxiliary line is wound on at least one side of the anode tube to be electrically connected,
And the cathode auxiliary line is wound on at least one side of the cathode tube to be electrically connected. delete The method according to claim 1,
Wherein at least one of the anode tube and the cathode tube
A redox flow cell having a coating layer formed of a nanomaterial on an inner surface thereof. The method of claim 3,
The coating layer
A redox flow cell formed of grapheme or carbon nanotube. The method according to claim 1,
Wherein at least one of the anode tube and the cathode tube
A redox flow cell that produces a low voltage difference at the inlet side of the anode electrolyte or cathode electrolyte and a high voltage difference at the outlet side. The method according to claim 1,
The frame
And a transparent window for transmitting sunlight to a portion facing the solar cell. The method according to claim 1,
The photovoltaic cell
A redox flow cell comprising a TiO ₂ film formed on a photoelectrode. The method according to claim 1,
Wherein the anode electrolyte comprises zinc,
Wherein the cathode electrolyte comprises iodine. 9. The method of claim 8,
The anode electrode side
(→) and discharge (←) from Zn ^{2 +} + 2e ^- ↔ Zn,
Upon charging, the photovoltaic cell is connected to the first electron injection line
Zn ^{2 +} + 2e ^- → Zn
And further charged into the anode electrolyte. 9. The method of claim 8,
The cathode side
3I ^- ↔ I ₃ ^- + 2e ^- charge (→) and discharge (←)
At the time of discharging, a second electron injection line is connected to the anode electrode side
I ₃ ^- + 2e ^{- -} > 3I ^-
And injecting electrons to replenish electrons in the cathode electrolyte. The method according to claim 1,
The anode tube
An anode electrolytic solution supply line for supplying the anode electrolytic solution of the anode electrolytic solution tank to the anode electrode via a first pump,
And an anode electrolytic solution collecting line for collecting the anode electrolytic solution from the anode electrode side to the anode electrolytic solution tank,
Wherein the charge / discharge line on both sides of the power source or the load,
And the anode auxiliary line is wound around the anode electrolyte recovery line to be electrically connected. 12. The method of claim 11,
The anode electrolyte recovery line
A redox flow cell wound in an anode additional line, wherein a separate voltage is applied to the anode additional line. The method according to claim 1,
The cathode tube
A cathode electrolytic solution supply line for supplying a cathode electrolytic solution of the cathode electrolytic solution tank to the cathode side via a second pump,
And a cathode electrolytic solution collecting line for collecting the cathode electrolytic solution from the cathode electrode side to the cathode electrolytic solution tank,
Wherein the charge / discharge line on both sides of the power source or the load,
And the cathode auxiliary line is wound on the cathode electrolyte recovery line to be electrically connected. 14. The method of claim 13,
The cathode electrolyte recovery line
Wherein the anode is wound in a cathode addition line and a separate voltage is applied to the cathode addition line.

Images