KR101519499B1 - Redox flow battery - Google Patents

Abstract

An aspect of the present invention is to provide a redox flow battery which controls the flow of an electrolyte containing bromine. According to an embodiment of the present invention, the redox flow battery comprises: a membrane which passes ion; electrode plates which are stacked to interpose spacers on both sides thereof by placing the membrane therebetween; a flow frame which accommodates the membrane and the electrode plate respectively to be bonded to each other in a stacking direction, sets an internal capacity between the membrane and the electrode plate, and includes a flow channel for providing the electrolyte to the internal capacity; a current collector plate which is bonded to both outsides of the electrode plate in order to collect current generated from the electrode plate; and an end cap which accommodates the current collector plate in order to draw out a bus bar connected to the current collector plate, and includes an inlet and an outlet of the electrolyte respectively, which are connected to the flow channel, wherein the spacer is formed in the form of mesh, and 52-69% of the internal capacity is used as a space for the electrolyte.

Description

Redox Flow Battery {REDOX FLOW BATTERY}

The present invention relates to redox flow cells.

It is known that a redox flow cell is constructed so that a bipolar electrode and a membrane are repeatedly stacked to form a stack, thereby achieving high output capacity.

The bipolar electrode plate is installed inside the electrode flow frame, and the membrane is installed inside the membrane flow frame. A pair of electrode flow frames and a membrane flow frame form a unit cell.

The redox flow battery includes a current collecting plate disposed on the outermost side and electrically connected to the bipolar electrode plate of the unit cell, a bus bar electrically connected to the outside of the current collecting plate, a bipolar electrode And an end cap for accommodating the plate and the front plate and drawing the bus bar to the outside.

The end cap has an electrolyte inlet and an electrolyte outlet for injecting and discharging the electrolyte. The electrode flow frame and the membrane flow frame have flow channel channels for passing the electrolyte through the adjacent unit cells.

Inside the electrode flow frame and the membrane flow frame that are in contact with each other, the spacer is received between the membrane and the bipolar electrode plate on both sides of the electrode flow frame and the membrane flow frame, and the internal volume set between the membrane and the bipolar electrode plate, . ≪ / RTI >

One aspect of the present invention is to provide a redox flow cell that controls the flow of electrolyte containing bromine. One aspect of the present invention is to provide a redox flow cell that improves the mixing of the heavy complexing Bromine and electrolyte produced during the reaction in the cell.

One aspect of the present invention is to provide a redox flow cell that controls and optimizes the flow of electrolyte and mid-dibromin flowing through the flow channel. Another aspect of the present invention is to provide a redox-flow battery that prevents clogging of a flow channel due to middle-stranded bromine through solution mixing while uniformly controlling the internal volume.

A redox flow cell according to an embodiment of the present invention includes a membrane for passing ions, an electrode plate stacked on both sides of the membrane with spacers interposed therebetween, And a flow channel which is adhered to each other to set an internal volume between the membrane and the electrode plate and supplies an electrolyte solution to the internal volume, And an end cap which houses the current collecting plate and draws out a bus bar connected to the current collecting plate and has an electrolyte inlet and an electrolyte outlet connected to the flow channel, And 52 to 69% of the internal volume is used as the space for the electrolyte solution.

The thickness of the spacer may be 66 to 100% of the space between the membrane and the electrode plate.

The internal volume may be 10.536 cm < 3 >, and the spacer thickness may be 0.66 to 1 mm.

The spacer has a thickness of 1 mm, and 52% of the internal volume can be used as the space for the electrolyte.

The spacer has a thickness of 0.8 mm, and 62% of the internal volume can be used as the space for the electrolyte.

The spacer has a thickness of 0.66 mm, and 69% of the internal volume can be used as the space for the electrolyte.

The thickness of the spacer may be greater than zero and less than 50% of the flow frame thickness.

The membrane and the electrode plate may have a rectangular side surface, and the spacer may be formed by crossing the mesh line in a diagonal direction with respect to the square.

The spacers may form mesh structures by weaving or integrating the mesh lines.

The spacer may have a protrusion protruding in the thickness direction of the spacer at an intersection of the mesh lines.

The spacer may be formed of any one of polypropylene, polyethylene and a fluorine-based polymer which are chemical resistant materials.

According to an embodiment of the present invention, since the spacer is provided between the membrane and the electrode plate in the flow frame, 52 to 69% of the internal volume set between the membrane and the electrode plate is used as the electrolyte space.

That is, the flow of the electrolytic solution can be controlled by the spacer. Spacers can improve the mixing of the heavy complexing Bromine and electrolyte produced during the reaction in the cell.

Mesh lines of the spacers are cross-formed diagonally to support the membrane so that the membrane is prevented from swelling in the internal volume. Therefore, the flow of the electrolyte and the middle-dibromin flowing through the channel can be controlled optimally.

That is, the spacer can prevent the flow channel from clogging by mixing the electrolyte and the middle-bodied bromine with the inner-volume pressure while adjusting the pressure of the inner volume.

1 is a configuration diagram of a redox flow cell according to an embodiment of the present invention.
Figure 2 is a perspective view of the stack as applied to Figure 1;
3 is an exploded perspective view of the stack of FIG.
4 is a cross-sectional view taken along the line IV-IV of FIG.
5 is a cross-sectional view taken along the line V-V in Fig.
FIG. 6 is a perspective view of a spacer according to the first embodiment applied to FIG. 1; FIG.
7 is a perspective view of a spacer according to a second embodiment applied to FIG.
8 is a cross-sectional view taken along the line VIII-VIII in FIG.
FIG. 9 is a perspective view of a spacer according to a third embodiment applied to FIG. 1; FIG.
10 is a cross-sectional view taken along the line X-X of Fig.

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. Referring to FIG. 1, a redox flow cell according to an embodiment includes a stack 100 for generating electric current by circulation of an electrolyte, and a cathode electrolyte tank (not shown) for introducing and discharging the cathode electrolyte and the anode electrolyte into the stack 100 200 and an anode electrolyte tank 300.

The electrolyte inflow lines L21 and L31 are connected to the electrolyte solution inlets H21 and H31 of the stack 100 through the first and second pumps P1 and P2 via the cathode electrolyte solution tank 200 and the anode electrolyte solution tank 300 Respectively. The electrolyte outflow lines L22 and L32 connect the cathode electrolyte tank 200 and the anode electrolyte tank 300 to the electrolyte outlets H22 and H32 of the stack 100, respectively.

The cathode electrolytic solution tank 200 contains a cathode electrolytic solution containing bromine and circulates the cathode electrolytic solution on the cathode side of the stack 100 by driving the first pump P1. The anode electrolyte tank 300 contains an anode electrolyte containing zinc and circulates the anode electrolyte at the anode side of the stack 100 by driving the second pump P2.

The stack 100 is connected to an external load through bus bars B1 and B2 to discharge the current generated in the stack 100 or to be connected to an external power source to supply power to the cathode electrolyte tank 200 and the anode 100. [ The electrolyte tank 300 can be charged with an electric current.

For example, the stack 100 is formed by stacking a plurality of unit cells (C1, C2). For convenience, the stack 100 formed by stacking two unit cells (C1, C2) is illustrated in this embodiment.

The electrolyte inlet ports H21 and H31 are provided in the left unit cell C1 and the electrolyte inlet ports H21 and H31 are connected to the electrolyte inlet lines L21 and L31 via the first and second pumps P1 and P2, And is connected to the electrolyte tank 200 and the anode electrolyte tank 300.

The electrolytic solution outlets H22 and H32 are provided in the right unit cell C2 and the electrolytic solution outlets H22 and H32 are connected to the cathode electrolytic solution tank 200 and the anode electrolytic solution tank 300 with the electrolyte solution outflow lines L22 and L32, Lt; / RTI >

The electrolyte inlets H21 and H31 flow the electrolyte solution from the cathode electrolytic solution tank 200 and the anode electrolytic solution tank 300 into the left unit cell C1. The electrolytic solution outlets H22 and H32 flow out the electrolytic solution flowing out from the right unit cell C2 to the cathode electrolytic solution tank 200 and the anode electrolytic solution tank 300 via the stack 100. [

Fig. 2 is a perspective view of the stack applied to Fig. 1, and Fig. 3 is an exploded perspective view of the stack of Fig. 2 and 3, the stack 100 includes a membrane 10, a spacer 20, an electrode plate 30, a flow frame (e.g., a membrane flow frame 40, an electrode flow frame 50, First and second collector plates 61 and 62 (see FIGS. 4 and 5), and first and second end caps 71 and 72. The first and second collector plates 61 and 62 (see FIGS.

For example, the stack 100 includes two unit cells (C1, C2), so that one electrode flow frame (50) is disposed at the center, and the electrode flow frame (50) Two membrane flow frames 40, and two first and second end caps 71 and 72, respectively, disposed on the outside of the membrane flow frame 40.

4 is a cross-sectional view taken along the line IV-IV in FIG. 2, and FIG. 5 is a cross-sectional view taken along line V-V in FIG. 3-5, the membrane 10 is configured to pass ions and is coupled to the membrane flow frame 40 at its center in the thickness direction. The electrode plate 30 is joined to the electrode flow frame 50 at the center in the thickness direction thereof.

The first end cap 71, the membrane flow frame 40, the electrode flow frame 50, the membrane flow frame 40 and the second end cap 72 are disposed and the membrane 10 and the electrode plate 30 The two unit cells C1 and C2 are bonded to each other by bonding the membrane frame 40, the electrode flow frame 50 and the first and second end caps 71 and 72 to each other with the spacers 20 interposed therebetween. The stack 100 is formed.

The electrode plate 30 has a structure in which the cathode electrode 31 is formed on one side and the anode electrode 32 is formed on the other side in the portion where the two unit cells C1 and C2 are connected to form the two unit cells C1 and C2, To form a bipolar electrode connecting in series. A carbon coating layer may be formed on the cathode electrode 31.

The membrane flow frame 40, the electrode flow frame 50 and the first and second end caps 71 and 72 are bonded together to establish an internal volume IV between the membrane 10 and the electrode plate 30 And a first and a second flow channel CH1 (see FIG. 4) and CH2 (see FIG. 5) for supplying an electrolyte to the internal volume IV. The first and second flow channel channels (CH1, CH2) are configured to supply the electrolyte at a uniform pressure and amount, respectively, on both sides of the membrane (10).

The membrane flow frame 40, the electrode flow frame 50 and the first and second end caps 71 and 72 are formed of an electrically insulating material containing a synthetic resin component and can be bonded by thermal welding or vibration welding.

The first flow channel CH1 is connected between the membrane 10 and the cathode electrode 31 by driving the pump P1 by connecting the electrolyte inlet H21, the internal volume IV and the electrolyte outlet H22, The cathode electrolytic solution is introduced into the internal volume IV to be set, and allowed to flow out after the reaction (see FIG. 4).

The second flow channel CH2 is connected between the membrane 10 and the anode electrode 32 by driving the pump P2 by connecting the electrolyte inlet H31, the internal volume IV and the electrolyte outlet H32, The anode electrolytic solution is introduced into the internal volume IV to be set and allowed to flow out after the reaction (see FIG. 5).

The cathode electrolytic solution is subjected to a redox reaction on the cathode electrode 31 side to generate a current and stored in the cathode electrolytic solution tank 200. The anode electrolytic solution performs a redox reaction on the anode electrode 32 side to generate a current, 300).

During charging, between the membrane 10 and the cathode electrode 31,

2Br ^- > 2Br + 2e ^- (1)

The bromine contained in the cathode electrolytic solution is produced and stored in the cathode electrolyte tank 200. At this time, the bromine is immediately mixed with the quaternary ammonium ions in the cathode electrolytic solution to form a high-density second phase that is immediately removed from the stack 100, such as the cathode electrolyte.

During charging, between the membrane 10 and the anode electrode 32,

Zn ²⁺ + 2e ^- ? Zn (Equation 2)

The zinc contained in the anode electrolyte is deposited on the anode electrode 32 and stored.

During the discharge, a reverse reaction of Equation 1 occurs between the membrane 10 and the cathode electrode 31, and an adverse reaction of Equation 2 occurs between the membrane 10 and the anode electrode 32.

The first and second current collectors 61 and 62 collect current generated in the cathode electrode plate 31 and the anode electrode plate 32 or collect the current generated in the cathode electrode plate 31 and the anode electrode plate 32 And is electrically connected to the outermost electrode plates 30 and 30 so as to supply current.

The bus bars B1 and B2 are electrically connected to the first and second current collectors 61 and 62 so as to draw current to the outside of the stack 100 or supply current to the stack 100. [

The first end cap 71 is integrally formed by receiving a first current collecting plate 61 connected to the bus bar B1 and an electrode plate 30 connected to the first current collecting plate 61, (100). The first end cap 71 may be molded by insert injection.

The second end cap 72 includes a second current collecting plate 62 connected to the bus bar B2 and an electrode plate 30 connected to the second current collecting plate 62. The second end cap 72 is integrally formed with the stack 100, Thereby forming the other outer edge of the other side. The second end cap 72 may be molded by insert injection.

The first end cap 71 has electrolytic solution inlets H21 and H31 on one side thereof and is connected to the first and second flow channel channels CH1 and CH2 so as to introduce the cathode electrolytic solution and the eardic electrolytic solution respectively. The second end cap 72 has electrolytic solution inlets H22 and H32 on one side thereof and is connected to the first and second flow channel channels CH1 and CH2 to discharge the cathode electrolytic solution and the eardoid electrolytic solution.

FIG. 6 is a perspective view of a spacer according to the first embodiment applied to FIG. 1; FIG. Referring to FIG. 6, the spacer 20 is formed of a mesh, and 52 to 69% of the internal volume IV can be used as the space of the electrolyte. At this time, the thickness t1 of the spacer 20 may be 66 to 100% of the gap G between the membrane 10 and the electrode plate 30.

For example, the internal volume IV may be 10.536 cm3, and the thickness t1 of the spacer 20 may be 0.66 to 1 mm. Also, the thickness t1 of the spacer 20 may be greater than zero and less than 50% of the thickness t2 of the flow frames 40, 50.

3 and 6, the membrane 10 and the electrode plate 30 are formed in a square shape on the side surface thereof, and the spacer 20 is formed by inserting the mesh lines 21 and 22 into the membrane 10 and the electrode plate 30 ) In a diagonal direction. The spacers 20 are formed by weaving the mesh lines 21, 22.

Comparative Example

Table 1 shows the charging and discharging efficiencies of the redox flow cell comprising a unit cell in which no spacer is used. Since no spacer is used, 100% of the internal volume (IV) is used as the electrolyte space.

Current efficiency Voltage efficiency Energy efficiency 1 cycle 32.48 78.21 25.40 2 cycles 35.74 78.80 28.16 3 cycles 38.32 77.31 29.62 4 cycles 39.80 78.27 31.15 5 cycles 43.10 79.49 34.26

Experimental Example  One

The charging and discharging efficiencies of the redox flow cell made up of the unit cells in which the spacers 20 having the thickness t1 of 1 mm are used are shown in Table 2. A thickness t1 of 1 mm is used as the spacer 20, so that 52% of the internal volume IV is used as the electrolyte space.

Current efficiency Voltage efficiency Energy efficiency 1 cycle 87.83 82.90 72.81 2 cycles 86.69 82.87 71.84 3 cycles 87.48 82.51 72.18 4 cycles 87.16 82.59 71.99 5 cycles 87.02 82.59 71.87

Experimental Example 2

The charging and discharging efficiencies of the redox flow cell made up of the unit cells in which the spacers 20 having the thickness t1 of 0.8 mm are used are shown in Table 3. The thickness t1 is 0.8 mm and the spacer 20 is used, so that 62% of the internal volume IV is used as the electrolyte space.

Current efficiency Voltage efficiency Energy efficiency 1 cycle 89.22 81.67 72.87 2 cycles 89.63 81.93 73.43 3 cycles 89.53 81.50 72.97 4 cycles 88.50 81.66 72.26 5 cycles 88.17 81.95 72.25

Experimental Example 3

Table 4 shows the charging and discharging efficiencies of the redox flow cell comprising the unit cell in which the spacer 20 having the thickness t1 of 0.66 mm is used. Since the spacer 20 having the thickness t1 of 0.66 mm is used, 69% of the internal volume IV is used as the electrolyte space.

Current efficiency Voltage efficiency Energy efficiency 1 cycle 88.45 81.40 72.00 2 cycles 88.23 81.52 71.92 3 cycles 88.31 81.57 72.03 4 cycles 88.06 80.98 71.31 5 cycles 88.33 81.01 71.56

As can be seen in Tables 1 to 4, the experiment using the spacer 20 has excellent current efficiency, voltage efficiency and energy efficiency, as compared with the comparative example in which the spacer is not used.

In other words, the spacer 20 of the present embodiment is accommodated in the internal volume IV to control the flow of the electrolytic solution. The spacer 20 optimally forms the internal volume IV and optimally controls the flow of the electrolytic solution.

As the spacer 20 is interposed in the internal volume IV, the flow of the cathode electrolyte and the middle-dentate bromine flowing from the cathode electrolyte tank 200 to the first flow channel CH1 is optimized, and thus excellent efficiency can be obtained .

The spacer 20 may be formed of polypropylene, polyethylene, or a fluorine-based polymer that is a chemical resistant material. Therefore, the spacer 20 can have excellent chemical resistance to a cathodic electrolytic solution based on bromine which is highly oxidative.

FIG. 7 is a perspective view of a spacer according to a second embodiment applied to FIG. 1, and FIG. 8 is a sectional view taken along the line VIII-VIII in FIG. Referring to FIGS. 7 and 8, the spacer 220 according to the second embodiment integrates the mesh lines 221 and 222 to form a mesh structure. That is, the plurality of mesh lines 221 form one layer, and the other plurality of mesh lines 222 are integrally formed on the mesh line 221 to form another layer.

FIG. 9 is a perspective view of a spacer according to a third embodiment applied to FIG. 1, and FIG. 10 is a cross-sectional view taken along the line X-X of FIG. 9 and 10, the spacer 320 according to the third embodiment has protrusions 323 protruding in the thickness direction of the spacer 320 at the intersections of the mesh lines 321 and 322.

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: membrane 20, 220, 320: spacer
21, 22, 221, 222, 321, 322: mesh line 30: electrode plate
31: cathode electrode 32: anode electrode
40: Membrane flow frame 50: Electrode flow frame
61, 62: first and second collectors 71, 72: first and second end caps
100: stack 200: cathode electrolyte tank
300: anode electrolyte tank 323: projection
B1, B2: bus bar C1, C2: unit cell
CH1, CH2: First and second flow channels IV: Internal volume
H21, H31: electrolyte inlet H22, H32: electrolyte outlet
L21, L31: electrolyte inflow line L22, L32: electrolyte efflux line
P1, P2: first and second pumps

Claims (11)

A membrane for passing ions therethrough;
An electrode plate laminated on both sides of the membrane with spacers interposed therebetween;
A flow channel having a membrane and an electrode plate, and a flow channel which is adhered to each other in a stacking direction to set an internal volume between the membrane and the electrode plate, and to supply an electrolyte solution to the internal volume;
A current collecting plate adhered to both outer sides of the electrode plate so as to collect current generated in the electrode plate; And
And an end cap which is provided with an electrolyte inlet and an electrolyte outlet connected to the flow channel, respectively, for receiving the bus bar connected to the current collector to the outside,
/ RTI >
Wherein the spacer is formed of a mesh,
Wherein 52 to 69% of the internal volume is used as the space for the electrolyte.
The method according to claim 1,
The spacer thickness
Wherein the distance between the membrane and the electrode plate is 66 to 100%.
The method according to claim 1,
The internal volume is 10.536 cm < 3 &
Wherein the thickness of the spacer is 0.66 to 1 mm.
The method according to claim 1,
The spacer has a thickness of 1 mm,
Wherein 52% of the internal volume is used as the space for the electrolyte.
The method according to claim 1,
The spacer has a thickness of 0.8 mm,
Wherein 62% of the internal volume is used as the space for the electrolyte.
The method according to claim 1,
The spacer has a thickness of 0.66 mm,
Wherein 69% of the internal volume is used as the space for the electrolyte.
The method according to claim 1,
The thickness of the spacer
0.0 > 50% < / RTI > of said flow frame thickness.
The method according to claim 1,
Wherein the membrane and the electrode plate have a rectangular side surface,
Wherein the spacers are formed by intersecting the mesh lines in a diagonal direction with respect to the rectangle.
9. The method of claim 8,
The spacer
A redox flow cell in which mesh lines are woven or integrated to form a mesh structure.
9. The method of claim 8,
The spacer
And a protrusion protruding in the thickness direction of the spacer at an intersection of the mesh lines.
The method according to claim 1,
The spacer
A redox flow cell formed of any one of polypropylene, polyethylene, and a fluorine-based polymer that is a chemical resistant material.

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