WO2018169358A1

WO2018169358A1 - Redox flow battery

Info

Publication number: WO2018169358A1
Application number: PCT/KR2018/003112
Authority: WO
Inventors: 정현진; 김대식; 최원석; 김태언; 정진교; 서동균; 김진후
Original assignee: 롯데케미칼 주식회사
Priority date: 2017-03-16
Filing date: 2018-03-16
Publication date: 2018-09-20
Also published as: KR20180105937A

Abstract

An aspect of the present invention is to provide a redox flow battery which minimizes the pipeline length outside an end plate by forming, at the end plate, a connection passage through which an electrolyte flows. A redox flow battery according to an embodiment of the present invention comprises: a first stack, the end plate of which includes an electrolyte inlet connected to an electrolyte inflow line, and a first connection passage connecting the electrolyte inlet to a first flow channel; and a second stack, the end plate of which includes an electrolyte outlet connected to an electrolyte outflow line, and a second connection passage connecting the electrolyte outlet to a second flow channel.

Description

Redox flow battery

The present invention relates to a redox flow cell, and more particularly, to a redox flow cell connecting end plates of neighboring stacks to each other.

As is known, zinc bromine redox flow cells are a type of flow cell that produce electricity through redox reactions between the electrolyte and the electrodes.

For example, a redox flow battery is formed by repeatedly laminating a bipolar electrode and a membrane, and laminating a current collector plate and an end plate on both sides of the outermost layer, and supplying electrolyte to oxidize the electrolyte. It includes a stack in which the reduction reaction occurs, a pump and a pipe for supplying the electrolyte solution to the stack, and an electrolyte tank for storing the electrolyte solution flowing out after the internal reaction in the stack.

In a redox flow cell, the electrolyte tank includes an anode electrolyte tank containing an anode electrolyte containing zinc, and a cathode electrolyte tank containing a cathode electrolyte containing bromine. The anode electrolyte tank and the cathode electrolyte tank are connected by an overflow tube to supply the insufficient electrolyte solution to each other.

The redox flow battery may include a plurality of stacks for increasing capacity. In this case, the end plates provided at both ends of each stack are supplied with an electrolyte solution from the outside, and are provided with a flow path for outflowing the electrolyte solution circulating through the stack to the outside. However, since the end plate is connected to an external pipe to transfer the electrolyte, the length of the pipe is increased, and thus the internal pressure of the stack is changed.

When the pipe is long, due to the difference in viscosity and specific gravity of the electrolyte generated during charging and discharging, crossover of the electrolyte occurs in the stack, the difference in the level of the electrolyte in the electrolyte tank occurs. Therefore, charge quantity efficiency falls and energy efficiency falls. Therefore, it is necessary to minimize the length of the pipe outside the end plate.

One aspect of the present invention is to provide a redox flow battery that forms a connection passage through which the electrolyte flows in the end plate to minimize the length of the pipe outside the end plate. One aspect of the present invention is to provide a redox flow battery that directly injects the electrolyte into the stack to minimize the difference in the internal pressure of the stack due to the difference in viscosity and specific gravity of the electrolyte during charging and discharging.

Redox flow battery according to an embodiment of the present invention, the first stack and the second stack, including the unit stack for generating a current and disposed adjacent to supply the electrolyte solution to the first stack and the second stack and the first An electrolyte tank for storing the electrolyte flowing out of the first stack and the second stack, and connecting the electrolyte tank with the first stack and the second stack to drive the electrolyte pump into the first stack and the second stack. An electrolyte inflow line, and an electrolyte outlet line connecting the electrolyte tank, the first stack, and the second stack to discharge the electrolyte from the first and second stacks, respectively, the first and second stacks, respectively. Silver, a membrane and a spacer and an electrode plate to be repeatedly stacked, a collector plate and an end plate are sequentially stacked on both ends of the stacking direction, and the interior set between the membrane and the electrode plate A first flow channel and a second flow channel for supplying an electrolyte to a volume, respectively, wherein the end plate of the first stack includes an electrolyte inlet connected to the electrolyte inlet line, and the electrolyte inlet to the first channel. And a first connection passage connecting to each other, wherein the end plate of the second stack includes an electrolyte outlet connected to the electrolyte outlet line, and a second connection passage connecting the electrolyte outlet to the second channel.

The end plate of the first stack forms an eleventh connection hole connected to the first connection passage, and the end plate of the neighboring second stack forms a twelfth connection hole connected to the first channel. The eleventh connection hole and the twelfth connection hole may be connected to the first fitting member.

The end plate of the first stack forms a twenty-first connection hole connected to the second channel, the end plate of the neighboring second stack forms a twenty-second connection hole connected to the second connection passage, The twenty-first connecting hole and the twenty-second connecting hole may be connected to the second fitting member.

The first connection passage may have a diameter smaller than or equal to the diameter of the electrolyte inflow line, and the second connection passage may have a diameter smaller than or equal to the diameter of the electrolyte outlet line.

In one embodiment of the present invention, by providing a connection passage in the end plate of the stack connects the electrolyte inlet and the electrolyte outlet to the flow channel can minimize the length of the pipe from the outside of the end plate.

In addition, one embodiment of the present invention, by forming a connection passage in the end plate directly injecting the electrolyte in the stack it is possible to minimize the internal pressure difference of the stack due to the difference in viscosity and specific gravity of the electrolyte during charging and discharging.

Therefore, the efficiency of the redox flow battery can be increased, the durability of the stack can be improved, and long-term cycle stability can be achieved. In addition, since the length of the pipe is reduced, the load of the electrolyte pump is reduced, so that the reaction speed in the stack can be improved.

1 is a block diagram of a redox flow battery according to an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a stack applied to FIG. 1.

3 is a cross-sectional view taken along line III-III of FIG. 2.

4 is a cross-sectional view taken along line IV-IV of FIG. 2.

5 is a side view of the end plate applied to the stack of FIG.

6 is a cross-sectional view taken along line VI-VI of FIG. 5.

7 is a cross-sectional view taken along the line VII-VII of FIG. 5.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like elements throughout the specification.

1 is a block diagram of a redox flow battery according to an embodiment of the present invention. Referring to FIG. 1, the redox flow battery according to an embodiment of the present invention includes a stack 120 generating an electric current and an

electrolyte tank

210 and 220 supplying an electrolyte to the stack 120 and storing an electrolyte flowing out of the stack 120. It includes.

FIG. 2 is a perspective view illustrating a stack applied to FIG. 1. Referring to FIG. 2, the stack 120 includes a first stack 121 and a second stack 122 disposed adjacent to each other. The first and

second stacks

121 and 122 are formed by stacking five unit stacks 110 on each side and electrically connecting them. The unit stack 110 is configured to generate a current in the circulation of the electrolyte.

Referring back to FIG. 1, the

electrolyte tanks

210 and 220 supply electrolyte to the first stack 121 and the second stack 122, and flow out from the first stack 121 and the second stack 122. It is configured to store the electrolyte, it is connected to the electrolyte inlet line (La1 Lc1) and the electrolyte outlet line (La2, Lc2).

For example, the

electrolyte tanks

210 and 220 include an anode electrolyte tank 210 containing an anode electrolyte containing zinc, and a cathode electrolyte tank 220 containing a cathode electrolyte containing bromine (for convenience, a cathode electrolyte solution). A two-phase electrolyte tank for accommodating two phases is omitted.

The electrolyte inflow line La1 Lc1 connects the anode and

cathode electrolyte tanks

210 and 220 to the stack 120 to introduce electrolyte into the stack 120 by driving the electrolyte pumps Pa and Pc. The electrolyte outlet lines La2 and Lc2 connect the anode and

cathode electrolyte tanks

210 and 220 to the stack 120 to discharge the electrolyte solution after the reaction via the stack 120 from the stack 120.

3 is a cross-sectional view taken along line III-III of FIG. 2, and FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 2. 2 to 4, the first stack 121 and the second stack 122 are sequentially stacked on both ends of the membrane 10, the spacer 20, the electrode plate 30, and the stacking direction. A first flow channel CH1 including the

current collector plates

61 and 62 and

end plates

71 and 73 and 72 and 74 to supply the electrolyte solution to the first stack 121 and supplying the electrolyte solution. The second channel CH2 is included in the second stack 122. The electrode plate 30 includes an anode electrode 32 on one side and a cathode electrode 31 on the other side.

FIG. 5 is a side view of the

end plates

71 and 73 applied to the stack of FIG. 2, FIG. 6 is a sectional view taken along the line VI-VI of FIG. 5, and FIG. 7 is a sectional view taken along the line VII-VII of FIG. 5. .

2, 3, 5 and 6, in the first stack 121, the end plate 71 is the electrolyte inlet (H21) connected to the electrolyte inlet line (La1), and the electrolyte inlet (H21) It includes a first connection passage (P1) for connecting to the first channel (CH1).

Since the first connection passage P1 is directly connected to the electrolyte inlet H21 of the electrolyte inlet line La1, the length of the pipe connected to the outside of the end plate 71, that is, the electrolyte inlet line La1 is shortened, and the electrolyte solution. The load of the pump Pa can be reduced.

The first connection passage P1 may have a diameter smaller than or equal to the diameter of the electrolyte inflow line La1. The diameter of the first connection passage (P1) may adjust the flow rate of the anode electrolyte flowing in.

2 and 3, in the first stack 121, the end plate 72 connects the electrolyte outlet H22 connected to the electrolyte outlet line La2, and the electrolyte outlet H22 to the first flow channel. And a first connection passage P1 connecting to CH1).

Since the first connection passage P1 is directly connected to the electrolyte outlet H22 of the electrolyte outlet line La2, the length of the pipe connected to the outside of the end plate 72, that is, the electrolyte outlet line La2 is shortened, and the electrolyte solution. The load of the pump Pa can be reduced.

The first connection passage P1 may have a diameter smaller than or equal to the diameter of the electrolyte outlet line La2. The diameter of the first connection passage P1 may adjust the flow rate of the anode electrolyte flowing out.

2, 4, 5, and 7, in the second stack 122, the end plate 73 is an electrolyte outlet H32 connected to the electrolyte outlet line Lc2, and an electrolyte outlet H32. It includes a second connection passage (P2) for connecting to the second channel (CH2).

Since the second connection passage P2 is directly connected to the electrolyte outlet H32 of the electrolyte outlet line Lc2, the length of the pipe connected to the outside of the end plate 73, that is, the electrolyte outlet line Lc2, is shortened, and the electrolyte solution. The load of the pump Pc can be reduced.

The second connection passage P2 may have a diameter smaller than or equal to the diameter of the electrolyte outlet line Lc2. The diameter of the second connection passage P2 may adjust the flow rate of the cathode electrolyte flowing out.

2 and 4, in the second stack 122, the end plate 74 connects the electrolyte inlet port H31 connected to the electrolyte inlet line Lc1, and the electrolyte inlet port H31 to the second flow channel. And a second connection passage (P2) connecting to CH2).

Since the second connection passage P2 is directly connected to the electrolyte inlet H31 of the electrolyte inflow line Lc1, the length of the pipe connected to the outside of the end plate 74, that is, the electrolyte inflow line Lc1 is shortened, and the electrolyte solution. The load of the pump Pc can be reduced.

The second connection passage P2 may have a diameter smaller than or equal to the diameter of the electrolyte inflow line Lc1. The diameter of the second connection passage (P2) can adjust the flow rate of the incoming cathode electrolyte.

2, 5, and 6, the end plate 71 of the first stack 121 is an eleventh connection hole H11 connected to the first channel CH1 and the first connection passage P1. ) And a twelfth connection hole H12 connected to the first flow channel CH1 of the end plate 73 of the neighboring second stack 122.

In the first and

second stacks

121 and 122, the eleventh connection hole H11 and the twelfth connection hole H12 of the

end plates

71 and 73 are connected to the first fitting member F1. The first fitting member F1 minimizes the connection distance between the

end plates

71 and 73, thereby preventing the flow rate charge of the introduced cathode electrolyte.

Referring to FIG. 2, the

end plates

72 and 74 are connected in the same structure on the cathode electrolyte outlet side by an eleventh fitting member F11 connected to a connection hole (not shown), thereby minimizing the connection distance and the flow rate of the electrolyte solution. The charge can be prevented.

Referring to FIGS. 2, 5, and 7 again, the end plate 71 of the first stack 121 forms the twenty-first connection hole H41 connected to the second flow channel CH2, The end plate 73 of the second stack 122 forms a twenty-second connecting hole H42 connected to the second channel CH2 and the second connecting passage P2.

In the first and

second stacks

121 and 122, the twenty-first connecting hole H41 and the twenty-second connecting hole H42 of the

end plates

71 and 73 are connected to the second fitting member F2. The second fitting member F2 minimizes the connection distance between the

end plates

71 and 73, thereby preventing the flow rate charge of the cathode electrolyte flowing out.

Referring to FIG. 2, the

end plates

72 and 74 are connected in the same structure at the anode electrolyte inflow side by a twenty-first fitting member F21 connected to a connection hole (not shown), thereby minimizing the connection distance and the flow rate of the electrolyte. The charge can be prevented.

Under the same conditions, when the conventional end plate was applied, the charge and discharge efficiency was 72.2%, and when the

end plates

71, 73, 72, and 74 of this embodiment were applied, the charge and discharge efficiency was increased to 73.4%. That is, the present embodiment improves the reaction speed in the first and

second stacks

121 and 122 to increase the efficiency of the redox flow battery.

Referring back to FIG. 1, the anode electrolyte tank 210 supplies an anode electrolyte between the membrane 10 and the anode electrode 32 of the stack 120 and the unit stack 110, and the membrane 10 and the anode electrode. The anode electrolyte which flows out between (32) is accommodated.

The cathode electrolyte tank 220 accommodates the cathode electrolyte supplied between the stack 120 and the membrane 10 of the unit stack 110 and the cathode electrode 31.

To this end, the anode electrolyte inflow line La1 connects the anode electrolyte tank 210 to the first and

second stacks

121 and 122, and the cathode electrolyte inflow line Lc1 connects the cathode electrolyte tank 220 to the first. And the

second stacks

121 and 122.

The anode electrolyte outlet line La2 connects the anode electrolyte tank 210 to the first and

second stacks

121 and 122, and the cathode electrolyte outlet line Lc2 is connected to the first and

second stacks

121 and 122. The cathode electrolyte tank 220 is connected.

The anode and cathode electrolyte inflow lines La1 and Lc1 are connected to the anode electrolyte tanks H21 and H31 of the first and

second stacks

121 and 122 via the anode and cathode electrolyte pumps Pa and Pc. 210 and the cathode electrolyte tank 220, respectively. The anode and cathode electrolyte outlet lines La2 and Lc2 connect the anode electrolyte tank 210 and the cathode electrolyte tank 220 to the electrolyte outlets H22 and H32 of the first and

second stacks

121 and 122, respectively.

The anode electrolyte tank 210 contains an anode electrolyte containing zinc, and the membrane 10 and the anode electrode 32 of the first and

second stacks

121 and 122 are driven by the anode electrolyte pump Pa. The anode electrolyte is circulated between

The cathode electrolyte tank 220 includes a cathode electrolyte containing bromine, and the membrane 10 and the cathode electrode of the first and

second stacks

121 and 122 are driven by the cathode electrolyte pump Pc. 31) circulate the cathode electrolyte between.

The cathode electrolyte inflow line Lc1 and the cathode electrolyte outflow line Lc2 connect the cathode electrolyte tank 220 to the first and

second stacks

121 and 122 through the four-way valve 205. It is possible to selectively perform inflow and outflow operations of the cathode electrolyte to the

second stacks

121 and 122.

In addition, in the first and

second stacks

121 and 122, the unit stack 110 may be adjacent to other unit stacks 110 that are adjacent to each other through the bus bars B1 and B2 (see FIGS. 1, 3, and 4). Electrically connected. The first and

second stacks

121 and 122 discharge current generated inside the unit stacks 110 through the bus bars B1 and B2, or are connected to an external power source 206 to connect the anode electrolyte tank ( 210 may be charged with a current.

For example, the unit stack 110 may be formed by stacking a plurality of unit cells C1 and C2. For convenience, this embodiment illustrates a unit stack 110 formed by stacking two unit cells C1 and C2. Since the unit stack 110 is stacked as illustrated in FIG. 2, first and

second stacks

121 and 122 are formed. The first and

second stacks

121 and 122 are adjacent to each other and disposed on the side surface.

3 and 4, the unit stack 110 further includes a flow frame, that is, a membrane flow frame 40 and an electrode flow frame 50. Since the unit stack 110 includes two unit cells C1 and C2, two membranes having one electrode flow frame 50 in the center and symmetrical structures on both sides of the electrode flow frame 50 are provided. Two

end plates

71, 73; 72, 74 are arranged outside the flow frame 40 and the membrane flow frame 40, respectively.

The membrane 10 is configured to pass ions and is coupled to the membrane flow frame 40 at the center of the thickness direction of the membrane flow frame 40. The electrode plate 30 is coupled to the electrode flow frame 50 at the center of the thickness direction of the electrode flow frame 50.

The

end plates

71 and 73, the membrane flow frame 40, the electrode flow frame 50, the membrane flow frame 40 and the

end plates

72 and 74 are disposed, and the membrane 10 and the electrode plate 30 are disposed. By joining the membrane flow frame 40, the electrode flow frame 50, and the

end plates

71, 73; 72, 74 with each other through the spacers 20, the two unit cells C1, C2 are connected. The unit stack 110 is provided.

The electrode plate 30 forms the cathode electrode 31 on one side and the anode electrode 32 on the other side at the portion where the two unit cells C1 and C2 are connected, thereby forming the two unit cells C1 and C2. To form a bipolar electrode connecting in series.

The membrane flow frame 40, the electrode flow frame 50 and the

end plates

71, 73; 72, 74 are bonded to each other to establish an internal volume S between the membrane 10 and the electrode plate 30, First and second channel channels CH1 and CH2 for supplying an electrolyte solution to the internal volume S are provided. The first and second flow channels CH1 and CH2 are configured to supply the electrolyte at uniform pressure and amount on both sides of the membrane 10, respectively.

As an example, the membrane flow frame 40, the electrode flow frame 50, and the

end plates

71, 73; 72, 74 may be formed of an electrical insulating material including a synthetic resin component, and may be bonded by heat fusion or vibration fusion. have.

The first channel CH1 connects the electrolyte inlet H21, the internal volume S and the electrolyte outlet H22, and drives the membrane 10 and the cathode electrode 31 by driving the cathode electrolyte pump Pc. The cathode electrolyte is introduced into the internal volume S set therebetween to allow flow out after the reaction.

The second channel CH2 connects the electrolyte inlet H31, the internal volume S and the electrolyte outlet H32, and drives the membrane 10 and the anode electrode 32 by driving the anode electrolyte pump Pa. The anode electrolyte is introduced into the internal volume S set therebetween to allow flow out after the reaction.

The anode electrolyte is redox-reacted at the anode electrode 32 side of the internal volume S to generate a current and stored in the anode electrolyte tank 210. The cathode electrolyte is redox-reacted at the cathode electrode 31 side of the internal volume S to generate a current and stored in the cathode electrolyte tank 220.

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

2Br ^{^-} → 2Br + 2e ^- (formula 1)

As a chemical reaction occurs, bromine included in the cathode electrolyte is produced and stored in the cathode electrolyte tank 220.

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

Zn ²⁺ + 2e ^- → Zn (Equation 2)

As a chemical reaction occurs, zinc contained in the anode electrolyte is deposited and stored on the anode electrode 32.

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

The

current collector plates

61 and 62 collect the currents generated by the cathode electrode 31 and the anode electrode 32, or the outermost electrode plate so as to supply current to the cathode electrode 31 and the anode electrode 32 from the outside. 30, 30) and are electrically connected.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

Description of the sign

10: membrane 20: spacer

30: electrode plate 31: cathode electrode

32: anode electrode 61, 62: current collector plate

71, 73: end plate 72, 74: end plate

110: unit stack 120: stack

121 and 122: first and second stacks 200: electrolyte tank

CH1, CH2: 1st, 2nd channel H11, H12: 11th, 12th connection hole

H21: (anode) electrolyte inlet H22: (anode) electrolyte outlet

H31: (cathode) electrolyte inlet H32: (cathode) electrolyte outlet

H41: 21st connection hole H42: 22nd connection hole

La1, Lc1: (anode, cathode) electrolyte inflow line

La2, Lc2: (anode, cathode) electrolyte spill line

Pa, Pc: electrolyte pump P1, P2: first and second connection passages

F1, F11: 1st, 11th fitting member F2, F21: 2nd, 21st fitting member

Claims

And a first stack and a second stack in which the membrane and the electrode plate are repeatedly stacked and disposed adjacent to each other, and end plates are stacked at both ends thereof.

Each of the first stack and the second stack includes a first flow channel and a second flow channel, respectively, for supplying an electrolyte to an internal volume.

The end plate of the first stack,

An electrolyte inlet connected to an electrolyte inflow line for introducing electrolyte into the first and second stacks, and a first connection passage connecting the electrolyte inlet to the first channel;

The end plate of the second stack,

A redox flow battery comprising an electrolyte outlet connected to an electrolyte outlet line for outflowing the electrolyte solution from the first and second stacks, and a second connection passage connecting the electrolyte outlet to the second channel.
The method of claim 1,

The end plate of the first stack forms an eleventh connection hole connected to the first connection passage,

An end plate of the neighboring second stack forms a twelfth connection hole connected to the first channel;

And the eleventh connection hole and the twelfth connection hole are connected to the first fitting member.
The method of claim 2,

An end plate of the first stack forms a twenty-first connection hole connected to the second channel;

An end plate of the neighboring second stack forms a twenty-second connecting hole connected to the second connecting passage,

And the twenty-first connecting hole and the twenty-second connecting hole are connected to a second fitting member.
The method of claim 1,

The first connection passage

It has a diameter less than or equal to the diameter of the electrolyte inlet line,

The second connection passage

Redox flow battery having a diameter less than or equal to the diameter of the electrolyte outlet line.