WO2017204530A1

WO2017204530A1 - Redox flow battery

Info

Publication number: WO2017204530A1
Application number: PCT/KR2017/005348
Authority: WO
Inventors: 이용희; 김미경; 강태혁
Original assignee: 롯데케미칼주식회사
Priority date: 2016-05-23
Filing date: 2017-05-23
Publication date: 2017-11-30
Also published as: KR20170132005A

Abstract

The present invention relates to a redox flow battery comprising: a stack including a plurality of battery cells laminated on each other; an electrolyte tank including a first chamber for storing a first electrolyte and a second chamber for storing a second electrolyte; and an electrolyte circulation part for supplying an electrolyte of the electrolyte tank to the stack and collecting, into the electrolyte tank, the electrolyte used in the stack, wherein the electrolyte circulation part includes: a first pipe connecting a lower side of the first chamber and the stack; a second pipe connecting the stack and an upper side of the first chamber; a first sub-pipe connected to a lower side of the second chamber; and a second sub-pipe connected to an upper side of the second chamber, and includes: a third pipe connecting the first sub-pipe and the second sub-pipe to the stack; and a fourth pipe connecting the stack and the upper side of the second chamber.

Description

[Explanation of invention]

[Name of invention]

Redox flow battery

Technical Field

The present disclosure relates to a redox flow battery, and more particularly, to a redox flow battery capable of maintaining performance even with a simpler configuration.

Background Art

Recently, with the development of renewable energy technologies such as solar and wind power generation, the demand for large-capacity power storage devices is increasing. The electric power storage device stores electric energy when a large amount of power is generated, and releases electric energy when a large amount of power is consumed, thereby eliminating the problem of fluctuations in power generation and inconsistency in supply and demand.

Renewable energy, such as solar and wind power, is dependent on highly volatile natural energy, making it difficult to measure power variability and securing power supply stability. Therefore, a large capacity power storage technology is required to accommodate the fluctuations of renewable energy and to smoothly supply power and efficiently utilize power generation facilities.

Redox (redox) flow batteries are secondary batteries for high-capacity power storage, and have low maintenance costs, operate at room temperature, and can independently design capacity and output. The redox flow battery includes a stack in which a plurality of cells are stacked, an electrolyte tank for storing the positive and negative electrolytes, and a circulation device such as a pump for supplying and discharging the positive and negative electrolytes to the stack.

In this case, a configuration such as an automatic control valve capable of automatically controlling their circulation may be further included for smooth circulation of the positive or negative electrolyte. However, a configuration such as an automatic control valve is difficult to manufacture, expensive, and damage due to continuous operation may be a factor that impairs the economics and durability of the redox flow battery.

[Detailed Description of the Invention] [Technical problem]

The present disclosure is to provide a redox flow battery that can maintain performance even with a simpler configuration.

In addition, the technical problem to be solved by the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned are clearly to those of ordinary skill in the art from the following description. It can be understood.

Technical Solution

Redox flow battery according to an embodiment of the present invention, an electrolyte tank and an electrolyte tank comprising a stack of a plurality of battery cells, a first chamber for storing the first electrolyte and a second chamber for storing the crab 2 electrolyte And an electrolyte circulation part for supplying an electrolyte solution to the stack, and recovering the electrolyte solution used in the stack to the electrolyte tank, wherein the electrolyte solution circulation part comprises: a first pipe connecting the lower side of the crab chamber and the stack; A second pipe connecting the upper side of the first chamber, a first sub pipe connected to the lower side of the second chamber, and a second sub pipe connected to the upper side of the second chamber, wherein the first sub pipe and the first sub pipe are connected to each other. 2 includes the sub-pipe and a fourth pipe for connecting the upper side of the third pipe and the stack ^and, the second chamber connecting the stack.

The electrolyte circulation unit may further include a first pump installed in the first pipe to circulate the first electrolyte and a second pump installed in the third pipe to circulate the second electrolyte.

The eleven sub-pipes may include a first valve positioned in the first sub-pipe to control the opening and closing of the first sub-pipe.

The electrolyte circulation unit may further include a connection pipe connecting the first chamber and the second chamber.

In this case, the connection pipe may include a second valve for controlling opening and closing of the connection pipe between the first chamber and the second chamber.

On the other hand, the connection pipe may be connected to the upper portion of the second chamber.

The redox flow battery of this embodiment may be a zinc-bromine flow battery. [Effects of the Invention]

According to the present disclosure, it is possible to provide a redox flow battery capable of exhibiting the same or similar performance with a simple configuration without adding an expensive and miscellaneous configuration such as an automatic bromine complex control valve. Therefore, the manufacturing cost can be reduced, and the space required for the installation of the complex bromine complex control valve can be saved, which is more economical. [Brief Description of Drawings]

1 is a schematic diagram of a redox flow battery according to an embodiment of the present invention. 2 is a partially enlarged perspective view of the redox flow battery shown in FIG. 1. 3 is an exploded perspective view illustrating one battery cell of the stack illustrated in FIG. 1.

Figure 4 is a graph showing the state of charge and discharge of the stack of redox flow battery according to an embodiment of the present invention.

[Form for implementation of invention]

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in the description of the present disclosure, the description of the already known function black configuration will be omitted to clarify the gist of the present disclosure.

Parts not related to the description are omitted for clarity of description, and like reference numerals designate like elements throughout the specification. In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of description, so the present disclosure is not necessarily limited to the illustrated.

1 is a schematic diagram of a redox flow battery 100 according to a first embodiment of the present invention, and FIG. 2 is a partially enlarged perspective view of the redox flow battery 100 shown in FIG. 1.

1 and 2, the redox flow battery 100 of the present embodiment includes a stack 20, an electrolyte tank 30, and an electrolyte circulation unit 40.

The stack 20 includes a plurality of battery cells 10, and the electrolyte tank 30 includes a first chamber 31 for storing the first electrolyte and a second chamber 32 for storing the second electrolyte. Include. In this case, referring to FIG. 1, the first electrolyte may be a cathode electrolyte, and the second electrolyte may be a cathode electrolyte. However, this is only an example and may vary depending on the connection position of the positive electrode and the negative electrode. The electrolyte circulation portion 40 supplies the first electrolyte and the crab 2 electrolyte stored in the first chamber 31 and the second chamber 32 of the electrolyte tank 30 to the stack 20, respectively, and is used in the stack 20. The first electrolyte solution and the second electrolyte solution are recovered to the electrolyte tank 30.

The redox flow battery 100 of the present embodiment may be a zinc-bromine redox flow battery. The zinc-bromine redox flow battery uses ZnBr ₂ as a positive electrode and a negative electrode electrolyte, and the reaction is as follows.

Cathode: Zn ^ Zn ²⁺ + 2e ^" Anode: Br ₂ + 2e— ^ 2ΒΓ

However, the present invention is not limited thereto, and may be a vanadium redox flow battery instead of a zinc-red redox flow battery. The vanadium redox flow battery uses H ₂ S0 ₄ as the positive electrode and the negative electrode electrolyte, and the reaction is as follows.

Cathode: V ²⁺ → V ³⁺ + e— Anode: V0 ₂ ⁺ + e ^" ^ V0 ²⁺

Redox flow battery 100 of the present embodiment is not limited to the above-described zinc-bream or vanadium type, any temperature can be applied as long as the temperature of the stack 20 is increased by the reaction heat to lower the temperature of the stack 20 Do.

3 is an exploded perspective view showing one battery cell 10 of the stack 20 ^′ shown in FIG. 1.

Referring to FIG. 3, the battery cell 10 includes the membrane 11, which is an ion exchange membrane, and the first and second porous electrodes 12 and 13, with the membrane 11 interposed therebetween; First and second flow frames 14 and 15 for fixing the first and second porous electrodes 12, 13 at the edges of the porous electrodes 12, 13, respectively; and the first and second porous electrodes 12, 13. 13 and a first electrode 16 and a second electrode 17, respectively located outside of 13). The first electrode 16 and the second electrode 17 may each function as either an anode electrode or a cathode electrode, and the function of the anode and the cathode is determined according to the direction of reaction and current occurring at each electrode.

In two adjacent battery cells 10, the first electrode 16 and the second electrode 17 are integrally formed, which is called a bipolar plate. First and second porosity The electrodes 12, 13 can be made of carbon felt, and the first and second electrodes 16, 17 can be made of graphite. Four holes for the electrolyte circulation are formed in the first and the second flow frames 14 and 15.

One of the four holes in the first flow frame 14 is the second electrolyte inlet, the other is the second electrolyte outlet, and the other two are the first electrolyte through holes. The flow path 14 is formed in the jet flow frame 14 between the second electrolyte inlet and the first porous electrode 12 and between the first porous electrode 12 and the second electrolyte outlet so that the second porous electrode 12 has a second flow path. Allow the electrolyte to flow.

One of the four holes in the second flow frame 15 is the first electrolyte inlet, the other is the first electrolyte outlet, and the other two are twelve electrolyte through holes. In the second flow frame 15, a flow path is formed between the system 1 electrolyte inlet and the second porous electrode 13 and between the system 2 porous electrode 13 and the first electrolyte outlet so that the system 1 is connected to the second porous electrode 13. Allow the electrolyte to flow.

Two types of redox couples (zinc-bromine or vanadium-vanadium, etc.) having different oxidation numbers contained in the first and second electrolytes react at the system 1 and the second porous electrodes 12 and 13 to prevent layer transfer and discharge. Is done. Specifically, layer conversion is performed by oxidation reaction, and discharge is performed by a reduction reaction. As described above, referring to FIGS. 1 and 2, the electrolyte tank 30 according to the present embodiment includes a crab chamber 31 storing a crab 1 electrolyte and a second chamber 32 storing a second electrolyte. It includes.

The first chamber 31 and the second chamber 32 of this embodiment are connected by a connecting pipe 47. The connection pipe 47 is disposed between the first chamber 31 and the second chamber 32, and may include a second valve 49 for controlling opening and closing of the connection pipe 47. In this case, the connection pipe 47 connected to the second chamber 32 may be connected to the upper portion of the crab chamber 32 to prevent the QBr described later from flowing into the first chamber 31.

The electrolyte circulation part 40 includes a crab 1 pipe 41, a second pipe 42, a third pipe 43, and a _fourth pipe 44. The first pipe 41 connects the lower side of the first chamber 31 and the stack 20, and the second pipe 42 connects the stack 20 and the upper side of the first chamber 31, and a third Piping 43 connects the second chamber 32 and the stack 20, the fourth The pipe 44 connects the stack 20 and the upper side of the second chamber 32.

On the other hand, the first pump 45 may be arranged in the crab 1 pipe 41 to assist in the circulation of the first electrolyte, and the second pump 46 may be arranged in the crab 3 pipe 43 to assist in the circulation of the second electrolyte. ) May be arranged.

In this case, the crab 3 pipe 43 includes a first sub pipe 43a connected to a lower side of the crab 2 chamber 32 and a second sub pipe 43b connected to an upper side of the crab 2 chamber 32, The first sub pipe 43a and the second sub pipe 43b may be joined to the third pipe 43 to be connected to the stack 20.

The first electrolyte of the first chamber 31 is supplied to the stack 20 through the first pipe 41 and provided to the second porous electrode 13 of each battery cell 10, each battery cell 10. At first, the first electrolyte solution, which has undergone chemical reaction, is recovered back to the first chamber 31 through the crab 2 pipe 42.

In addition, the electrolyte circulation part 40 includes a third pipe 44 connecting the lower side of the second chamber 32 and the crab 2 electrolyte inlet of the stack 20, the crab 2 electrolyte outlet and the third of the stack 20. The crab 4 pipe 45 which connects the upper side of the chamber 33, and the crab 2 pump 46 provided in the crab 3 pipe 44 to circulate a 2nd electrolyte solution are included.

The Crab 2 electrolyte of the second chamber 32 is supplied to the stack 20 through the third pipe 44 and provided to the first porous electrode 12 of each battery cell 10, each battery cell 10. At the chemical reaction, the second electrolyte is recovered to the crab 3 chamber 33 through the crab 4 pipe 45.

As the fourth pipe 45 is connected to the upper side of the second chamber 32, at the initial stage of operation of the redox flow cell 100, the second electrolyte is collected in the second chamber 32 and QBr is precipitated downward. QBr precipitated system 2 electrolyte may be moved to the third pipe 43 through the first sub pipe 43a connected to the lower part of the second chamber 32, and the second electrolyte solution from which QBr is separated The sub pipe 43b may be moved to the system 3 pipe 43. The second electrolyte solution of the second chamber 32 moved to the third pipe 43 is supplied back to the stack 20 through the nearly 13 pipe 44.

The first sub pipe 43a may be provided with a first valve 48 for controlling opening and closing of the first sub pipe 43a. The first valve 48 regulates the flow of QBr precipitated in the two chambers 32 by controlling the opening and closing of the first sub pipe 43a. In the case of the zinc-bromine redox flow battery according to the present embodiment, when the layer is advanced, the activated carbon coated on the first porous electrode 12 and the second electrolyte serving as an anode electrolyte, for example, cause reaction reaction. Inside the stack a reaction deposit, QBr, is produced.

QBr is a bromine complex (Bromine Compex), a cathode active material, and is a heavy and viscous material with high specific gravity. QBr generates electricity by reacting when discharged, but does not affect reaction when re-introduced into the stack 20 during layer deposition. However, when re-introduced into the stack 20, QBr is a heavy and somewhat high viscosity material, which affects the pump speed, resulting in a slow flow rate and high power consumption. In addition, the QBr should be removed at the beginning of operation since it may function to remove zinc metal accumulated in the second porous electrode 13 at a later reaction. In this embodiment, the QBr can be separated from the system 2 electrolyte containing QBr using a heavy property, which is one of QBr's characteristics, without any additional configuration, such as an automatic bridging control valve that automatically controls the inflow of QBr. Can be. To this end, in the present embodiment, the first sub pipe 43a connected to the lower part of the second chamber 32 storing the second electrolyte solution and the second sub pipe 43b connected to the upper end of the second chamber 32 are provided. It includes each.

The second electrolyte delivered from the stack 20 to the second chamber 32 by the fourth pipe 44 after the layer transfer of the redox flow battery 100 of the present embodiment in the stack 20 is QBr. It includes. In the second chamber 32, QBr has a high specific gravity and is heavy, so that it is precipitated to the lower part of the second chamber 32 as shown in FIGS. 1 and 2, and the water-soluble anolyte electrolyte is disposed on the upper part of the second chamber 32. Will exist.

As described above, the lower part of the second chamber 32 is connected to the first sub pipe 43a including the first valve 48 so that the QBr stack 20 is closed by closing the first valve 48 when the floor is floored. ), And when discharged, the U-valve 48 can be opened to generate QBr into the stack 20 to generate power. On the other hand, the second sub-pipe 43b is connected to the upper part of the second chamber 32, so that when QBr is precipitated and the water-soluble anolyte electrolyte rising above it is stored above a certain level, only the water-soluble anolyte electrolyte from which QBr is separated is stacked ( With 20) It can flow in.

The configuration of the redox flow battery 100 according to the exemplary embodiment of the present invention has been described above. Hereinafter, a result of comparing the performance of the redox flow battery 100 according to the present embodiment and the redox flow battery according to the comparative example will be described.

In the redox flow battery 100 according to the present embodiment, the second chamber 32 in which the system 2 electrolyte is stored is formed as one, and the system 1 sub pipe 43a including the first valve 48 is provided at the bottom thereof. The second sub pipe 43b is connected to the upper portion. The redox flow cell according to the comparative example includes an automatic bromine complex regulating valve which automatically regulates the inflow of QBr.

4 is a graph showing the layer charge and discharge states of the stack 20 of the redox flow battery 100 according to an embodiment of the present invention. Depending on the operating conditions of the battery, if an abnormality occurs in the operating conditions, several peaks appear in the layer curve or the discharge curve. This is because the electrolyte is not uniformly supplied into the stack 20, or the substances to be reacted in the electrolyte container are not properly introduced into the stack 20, and when a large amount is introduced at a time or is accumulated in the electrolyte container. Occurs in the case.

Referring to the graph of FIG. 4, when the constant current 20A is applied during the layer charging of the redox flow battery 100 according to the present embodiment, a complex peak does not occur in the graph, so that the voltage is stably maintained without large fluctuations. It can be seen that the layer is made. Similarly, when the constant current -20A is discharged from the redox flow battery 100 in the discharge of the redox flow battery 100 according to the present embodiment, since a complex peak does not occur in the graph, the voltage does not change significantly. It can be seen that the reduction is stable.

Therefore, referring to FIG. 4, in the case of the redox flow battery 100 according to the present exemplary embodiment, even when the redox flow control valve is not included as in the comparative example, the layered and discharged can be stably formed. have. [Table 1] shows the energy efficiency (Energy Ef fi ciency, EE), the coolant efficiency (Coulombi c Ef f iciency, CE) and the voltage according to the layer charge and discharge results of the redox flow battery 100 according to the present embodiment Efficiency (Voltage Ef fi ciency, VE). At this time, [Table The data described in [1] are numerical values that summarize the results of the graph shown in FIG.

Table 2 shows energy efficiency (EE), Coulomb ic Efficiency (CE), and voltage efficiency (Voltage Efficiency, VE) according to the layer charge and discharge results of the redox flow battery according to the comparative example.

Table 1

As shown in [Table 1] and [Table 2], only the connection position of the first sub pipe 43a and the crab 2 sub pipe 43b is adjusted without including the separate automatic bromine complex control valve as in the present embodiment. By just doing so, similar results can be obtained as in the comparative example including the automatic bromine complex control valve.

[Table 3] shows the results of the pressure values at the positive and negative electrolyte inflows during layer discharge and discharge. The data described as "anode" is the pressure value of the redox flow battery 100 according to this embodiment, and the data described as "existing anode" is the pressure value of the redox flow battery according to the comparative example.

Table 3

As shown in [Table 3], the result of 2 hours lamination was slightly lower than that of the comparative example, but as in [Table 1] and [Table 2], most of the experimental results were the same or similar to the comparative example. can confirm. As described above, it can be seen that the redox flow battery 100 according to the present embodiment may exhibit the same or similar performance even with a simpler configuration.

So far, the redox flow battery 100 according to the exemplary embodiment of the present invention has been described. According to the present embodiment, it is possible to provide a redox flow battery 100 capable of performing the same or similar performance with a simple configuration without the addition of an expensive and complicated configuration such as an automatic bromine complex control valve. Therefore, the manufacturing cost can be reduced, and the space required for the installation of the complex bromine complex control valve can be saved, which is more economical.

While specific embodiments of the invention have been described and illustrated above, it is to be understood that the invention is not limited to the described embodiments, and that various modifications and changes can be made without departing from the spirit and scope of the invention. It is self-evident to those who have. Therefore, such modifications or variations are not to be understood individually from the technical spirit or viewpoint of the present invention, and the modified embodiments shall belong to the claims of the present invention.

[Explanation of code]

100 ： redox flow battery 10 ： battery cell

11: membrane 12: first porous electrode

13 ： second porous electrode 14 ： low u flow frame

15: 2nd flow frame 16: 1st electrode

17 ： Crab 2 electrode 20 ： Bfl

30: electrolyte tank 31: chamber

32: 2nd chamber 40: electrolyte solution circulation part

41: 1st piping 42: 2nd piping ： 3rd piping 43a: 1st subb: 2nd subpipe 44: 4th piping ： 1st pump 46: 2nd pump ： connection piping 48: 1st valve: 2nd valve

Claims

[Claim]

[Claim 1]

A stack in which a plurality of battery cells are stacked;

An electrolyte tank comprising a first chamber storing a first electrolyte and a second chamber storing a second electrolyte; And

An electrolyte circulation part for supplying an electrolyte solution of the electrolyte tank to the stack, and recovering the electrolyte solution used in the stack to the electrolyte tank,

The electrolyte solution circulation portion,

A first pipe connecting the lower side of the first chamber and the stack;

A second pipe connecting the stack and the upper side of the first chamber;

A first sub pipe connected to a lower side of the second chamber and a second sub pipe connected to an upper side of the second chamber, and connecting the first sub pipe and the second sub pipe to the stack 3 pipe; And

Redox flow battery comprising four pipes connecting the stack and the upper side of the second chamber.

[Claim 2]

The method of claim 1,

The electrolyte solution circulation unit,

A first pump installed in the first pipe to circulate the first electrolyte solution; And a second pump installed in the third pipe to circulate the second electrolyte.

[Claim 3]

In U,

The first sub pipe is,

And a first valve positioned in the first sub pipe, the first valve configured to control opening and closing of the first sub pipe.

[Claim 4]

The method of claim 1,

The electrolyte solution circulation unit,

The redox flow battery further comprises a connection pipe connecting the first chamber and the second chamber.

[Claim 5]

According to claim 4,

The connecting pipe is,

And a second valve for controlling opening and closing of the connecting pipe between the first chamber and the second chamber.

[Claim 6]

The method of claim 4,

The connecting pipe is connected to the upper portion of the second chamber, redox flow battery.

[Claim 7]

The method of claim 1,

The redox flow battery is a zinc-bromine flow battery, redox flow battery.