KR20130054548A - Redox flow battery - Google Patents

Abstract

PURPOSE: A redox flow battery is provided to improve output of a battery by a simple method without sudden increase of volume. CONSTITUTION: A redox flow battery has a structure formed by laminating two or more unit cells which includes manifold(40) with reaction parts(43,73,73') having different polarity from each other. The redox flow battery has a first end plate(10) which has different electrolyte inlets(11,11'); a second end plate(20) which has electrolyte outlets(21,21'); two or more current collectors(30,30') having different polarities; and a series and parallel connection element(80) formed on the front side of the second end plate.

Description

Redox Flow Battery {REDOX FLOW BATTERY}

The present invention relates to a redox flow battery having a series and a parallel structure at the same time.

With the recent increase in the share of renewable energy, power storage devices have attracted attention as a new alternative to overcome the problem of volatility and supply-demand inconsistency in power generation, and active research on power storage devices is being conducted. Electric power storage devices can effectively fill the gap between demand and supply by charging electricity when power generation is high and discharging electricity when power consumption is high, and are the safest way to cope with fluctuations in generation of renewable energy in a short time. In addition, if the share of renewable energy increases sharply, it is expected that the volatility of electric power generation will be small. The IEA is focusing on power storage devices to supply renewable energy in the future. The spread of storage devices is indispensable for expanding renewable energy.

Secondary batteries for large-capacity power storage include lead acid batteries, NaS batteries, and redox flow batteries (RFBs). Although lead acid batteries are widely used commercially compared to other batteries, they have disadvantages such as maintenance costs due to low efficiency and periodic replacement and disposal of industrial wastes caused by battery replacement. The NaS battery has a disadvantage in that it operates at a high temperature of 300 ° C or higher, although it has an advantage of high energy efficiency. In comparison, the redox flow battery has a lot of research into a large capacity secondary battery since the maintenance cost is low, it can operate at room temperature, and the capacity and output can be designed independently.

In general, a redox flow battery includes a cathode cell including an anode and a cathode electrolyte, an anode cell including a cathode and an anode electrolyte, and an ion exchange membrane positioned between the anode cell and the cathode cell. The redox flow battery may further include a positive electrolyte tank in which the positive electrolyte is stored, a negative electrolyte tank in which the negative electrolyte is stored, and a pump formed to circulate the positive electrolyte and the negative electrolyte. The electromotive force of the battery is determined by the difference between the standard electrode potentials of the redox couple constituting the positive and negative electrolytes.

In the redox flow battery having such a configuration, charge and discharge occur according to the flow of the positive electrolyte solution and the negative electrolyte solution. That is, the positive electrolyte and the negative electrolyte are circulated while flowing along the electrolyte passage of the cell of each electrode during charging and discharging. In this process, redox couples are charged or discharged as a redox reaction occurs. Discharge is caused by flowing, and charging is progressed by allowing a current to flow from the outside. Accordingly, the redox flow battery is very useful for storing an externally generated current.

In the case of the unit cell of the redox flow battery having the above-described structure has a disadvantage that the output is small, accordingly, a technique for stacking a plurality of unit cells in order to increase the output of the battery is disclosed in recent years. In this regard, the present applicant has disclosed a technology of a redox flow battery having a stacked structure as shown in FIG. 1 in Korean Patent Application No. 2010-36151. The redox flow battery illustrated in FIG. 1 includes a stack in which bipolar plates, electrode plates, and separators are sequentially stacked between current collectors in series.

However, the structure has a disadvantage in that the volume of the redox flow battery increases rapidly because the number of units to be stacked must be increased when the output of the redox flow battery is increased. In addition, although the size of the separator must be increased by another method for increasing the output, there is a disadvantage in that it is not easy to increase the size of the separator.

Accordingly, the present inventors have conducted research to solve the problems of the conventional redox flow battery, and can easily form a stack without rapidly increasing the volume of the redox flow battery to improve the output of the battery. After studying the method, the present invention was completed.

Accordingly, an object of the present invention is to provide a redox flow battery capable of improving the output of the battery in an easy manner without rapidly increasing the volume.

In order to achieve the above object, the present invention provides a redox flow battery having a structure formed by stacking two or more units of a unit cell including a manifold having a reaction part having different poles in one plate. .

The redox flow battery includes a first end plate having an electrolyte injection hole, a second end plate having an electrolyte discharge hole, two current collectors having different poles as located on a rear surface of the first end plate, and the current collector. It may be made of a unit cell, which is laminated to the rear side of the and the parallel connection member formed on the front surface of the second end plate.

The unit cell may include a first manifold having an anode electrode and a cathode electrode attached to one side thereof and having an anode reaction unit and a cathode reaction unit having polarities corresponding to the anode electrode and the cathode electrode on the other side thereof; A gasket including a separator formed at a position corresponding to the anode reaction part and the cathode reaction part; And a cathode reaction part and an anode reaction part having polarities opposite to the anode reaction part and the cathode reaction part of the first manifold at a position corresponding to the separator, and at one side of the cathode reaction part and the anode reaction part. It comprises a second manifold provided with a corresponding cathode electrode and anode electrode,

The front surface of the first manifold of the other unit cell may be located at the rear of the second manifold.

The positive electrode or the negative electrode formed on the rear surface of the second manifold may be made of a bipolar plate integrated with a single electrode and the negative electrode or the positive electrode formed on the front surface of the first manifold of another unit cell.

The positive electrode or the negative electrode may be a conductive graphite plate.

The anode reaction part may include a flow path of the positive electrolyte, and the cathode reaction part may include a flow path of the negative electrolyte.

Felt electrodes may be formed on both surfaces of the separator of the gasket.

In the manifold to which the positive electrode and the negative electrode are attached, a groove into which a part of the positive electrode and the negative electrode is inserted may be formed.

The series-parallel connection member may be made of a conductive plate, and the positive electrode and the negative electrode attached to the rear surface of the second manifold of the last unit cell stacked on the conductive plate may be in contact with each other.

The parallel-connecting member may have a conductive plate inserted in the center thereof, and the positive electrode and the negative electrode attached to the rear surface of the second manifold of the last unit cell stacked on the conductive plate may be in contact with the conductive plate. .

The positive electrolyte or negative electrolyte may be an aqueous electrolyte, a non-aqueous electrolyte, an ionic liquid, or a mixture thereof.

The redox flow battery may further include a positive electrolyte tank for storing the positive electrolyte, a negative electrolyte tank for storing the negative electrolyte, and a pump for circulating the positive electrolyte and the negative electrolyte.

As described above, the redox flow battery of the present invention forms a series and a parallel structure simultaneously by connecting unit cells including a manifold in which a reaction part having different poles is formed on one plate in series, so that the same number as in the prior art can be obtained. Since a higher voltage is formed than when a stack is formed, there is a useful effect of not only maximizing the output of the battery but also reducing the battery volume despite the increase in the output.

1 is a view showing a laminated structure of a conventional redox flow battery,
2 is a view schematically showing a laminated structure of a redox flow battery according to an embodiment of the present invention,
3 is a schematic diagram of a redox flow battery according to the present invention,
4A and 4B are schematic views of the front and rear surfaces of a manifold according to one embodiment of the present invention,
5 is a view schematically showing a series-parallel connection member according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a view schematically showing a laminated structure of a redox flow battery according to an embodiment of the present invention, Figure 3 is a schematic diagram of a redox flow battery according to the present invention, Figures 4a and 4b is one of the present invention 5 is a schematic view of a front and rear surface of a manifold according to an embodiment, and FIG. 5 is a view schematically showing a parallel-parallel connection member according to the present invention.

As shown in Figures 2 to 5, the redox flow battery according to the present invention is a manifold (40, 40) formed with a reaction portion 43, 43 'or 73, 73' having different poles on one plate It has a structure formed by stacking two or more unit cells 100 including ', 70,70'.

That is, the conventional unit cell has a structure in which one reaction unit is formed in one plate, but the unit cell 100 of the present invention has at least two reaction units 43, 43 'or 73 having different poles in one plate. 73 ') has a stacked structure including manifolds 40, 40', 70, 70 'formed.

More specifically, the redox flow battery according to the exemplary embodiment of the present invention may include a first end plate 10 having a positive electrolyte and a negative electrolyte injection ports 11 and 11 ′, and a positive electrolyte and a negative electrolyte discharge port 21. 21 '), the second end plate 20, two current collectors 30 and 30' having different poles, which are located at the rear of the first end plate 10, and the current collector 30 And a unit cell 100 stacked on the rear side of the 30 ', and a serial and parallel connection member 80 formed on the front surface of the second end plate 20.

At this time, the unit cell 100 is the positive electrode and the negative electrode (41, 41 ') is attached to one side and the other side of the positive electrode reaction portion of the polarity corresponding to the positive electrode and the negative electrode (41, 41') and Gasket 60 including a first manifold 40 having cathode reaction portions 43, 43 'and a separator 65 formed at positions corresponding to the anode reaction portions and cathode reaction portions 43, 43'. ) And a cathode reaction part and an anode reaction part having a polarity opposite to the anode reaction part and the cathode reaction part 43 and 43 'of the first manifold 40 at a position corresponding to the separator 65. A second manifold 70 having a cathode electrode and an anode electrode 71, 71 ′ corresponding to the cathode reaction part and the anode reaction part 73, 73 ′ on the other side thereof. It may be made to include.

When stacking the unit cells 100, the front surface of the first manifold 40 ′ of another unit cell is positioned on the rear surface of the second manifold 70. In this case, in FIG. 2, two unit cells 100 are illustrated, but as illustrated in FIG. 3, a plurality of other unit cells 100 may be stacked, which is based on the embodiment illustrated in FIG. 2. Is easy to implement.

Although not shown in the drawing, the redox flow battery further includes a positive electrolyte tank for storing the positive electrolyte, a negative electrolyte tank for storing the negative electrolyte, and a pump for circulating the positive electrolyte and the negative electrolyte. This can be easily implemented by those skilled in the art, a detailed description thereof will be omitted.

As described above, the redox flow battery according to the present invention adopts a series and parallel structure at the same time to form a higher voltage than the redox flow battery having a conventional series structure, thus maximizing the output of the redox flow battery In addition to increasing the power, the volume of the redox flow cell can be reduced.

Each component will be described in more detail as follows.

The first end plate 10 has positive electrode electrolyte and negative electrolyte injection ports 11 and 11 ', and the second end plate 20 has positive electrode electrolyte and negative electrolyte discharge ports 21 and 21'. It is to form a passage through which the electrolyte can be injected or discharged to a conventional plate generally used in the field.

The electrolyte injection holes 11 and 11 'and the electrolyte discharge holes 21 and 21' may be disposed diagonally to each other or deflected in the same direction, but the present invention is not limited thereto.

The electrolyte injection ports 11 and 11 'and the electrolyte discharge ports 21 and 21' are connected to the positive electrolyte tank and the negative electrolyte tank, and the positive electrolyte and the negative electrolyte are circulated by the driving of a separate pump.

In the above, the first end plate 10 and the second end plate are positioned at the outermost side when the unit cells 100 of the redox flow battery are stacked, and serve to hold a position when pressure is applied during the lamination. In addition, it helps to inject and drain the electrolyte.

The first end plate 10 and the second end plate 20 may be formed using an insulator. Specifically, it may be formed using a polymer such as polyethylene (PE), polypropylene (PP), polystyrene (PS) and vinyl chloride (PVC), and considering the price and ease of purchase, using vinyl chloride (PVC) It is desirable to.

Two current collectors 30 and 30 ′ having different poles are formed on the rear surface of the first end plate 10. The current collectors 30 and 30 ′ are passages through which external electrons move and serve to receive electrons from the outside during charging or to give out electrons to the outside during discharge.

The current collectors 30 and 30 'are generally used in the art and are not particularly limited. For example, copper or brass may be used.

According to the present invention, the unit cells 100 are stacked on the rear sides of the current collectors 30 and 30 ', and the unit cells 100 include a gasket including a first manifold 40 and a separator 65. 60) and the second manifold (70).

The first manifold 40 has anode and cathode electrodes 41 and 41 'attached to one side thereof, and an anode reaction portion having a polarity corresponding to the anode and cathode electrodes 41 and 41' attached to the other side thereof. And cathode reaction portions 43 and 43 '. The second manifold 70 includes the same configuration as the first manifold 40, except that the positive electrode and the negative electrode 71 and 71 ', the positive electrode and the negative electrode, 73 and 73'. The positions of are interchanged with each other. Therefore, the following description of the structure of the manifold will be described with reference to the shape of the first manifold 40 shown in FIGS. 4A and 4B.

The anode and cathode electrodes 41 and 41 'formed on the manifold 40 may use a conductive plate generally used in the art.

Preferably, the anode and cathode electrodes 41 and 41 'may use a conductive graphite plate. The conductive graphite plate serves to prevent corrosion of the current collector. Specifically, since the redox electrolyte is formed by dissolving the active material in a strong acid, in the absence of the conductive graphite plate, the current collector is corroded by the strong acid, thereby increasing resistance.

Preferably, the anode and cathode electrodes 41 and 41 'may be graphite plates impregnated with a phenol resin. In the case where the graphite plate is used alone, it is preferable to use a graphite plate impregnated with phenol resin in order to prevent the permeation of strong acid because the strong acid used in the electrolytic solution can permeate the graphite.

The manifold 40 may be formed with a groove 42 into which a portion of the cathode and anode electrodes 41 and 41 'may be inserted.

The positive and negative reaction portions 43 and 43 'formed on the other side of the manifold 40 respectively have flow paths 44 and 44' which are passages for the movement of the positive electrolyte or passages for the movement of the negative electrolyte. It is included.

The flow paths 44 and 44 ′ formed in the manifold are introduced into the electrolyte solution through the electrolyte injection holes 11 and 11 ′ of the first end plate 10, and then the electrolyte discharge ports 21 and 21 of the second end plate 20. ') Provides a predetermined flow passage for the reaction until the electrolyte is discharged. The flow path 43 or 43 'of the positive electrolyte solution and the flow path 43' or 43 of the negative electrolyte solution can be appropriately formed on one plate within a range not overlapping each other. The present invention does not limit the shape of the flow paths 43 and 43 '.

The plate forming the manifold 40 may be formed using a polymer such as polyethylene (PE), polypropylene (PP), polystyrene (PS) and vinyl chloride (PVC), price and ease of purchase In consideration, it is preferable that it is formed using vinyl chloride (PVC).

When the unit cells 100 are stacked, the front surface of the first manifold 40 ′ of the other unit cells 100 is positioned on the rear surface of the second manifold 70. At this time, the positive electrode or the negative electrode formed on the rear surface of the second manifold 70, the negative electrode or the positive electrode formed on the front surface of the first manifold 40 'of the other unit cell 100 and one plate Integral bipolar plates can be used.

The bipolar plate may be applied to those commonly used in the art. In addition, all or part of the bipolar plate may be applied to the graphite plate as described above.

A gasket 60 including a separator 65 is formed between the first manifold 40 and the second manifold 70.

The separator 65 separates the electrolyte from the cathode electrolyte and the cathode during charging / discharging, and selectively moves only ions during charging / discharging. The separator 65 is generally used in the art and is not particularly limited.

In addition, the gasket 60 serves to prevent leakage of the electrolyte. The gasket 60 may be formed of a material such as soft PVC, rubber, viton, hard PVC, and the like commonly used in the art.

According to the present invention, both surfaces of the separator 65 of the gasket 60, that is, the separator 65 between the gasket 60 and the first manifold 40 and the gasket 60 and the second manifold 70. The both sides of the felt electrode 50 may be provided. The felt electrode 50 provides an active site capable of redox of the electrolyte, and specifically, a nonwoven fabric, carbon fiber, carbon paper, or the like may be used.

When the unit cell 100 is stacked, the front surface of the first manifold 40 ′ of the other unit cell 100 is positioned on the rear surface of the second manifold 70. At this time, the number of the stacked unit cells 100 is not limited and may be appropriately modified to suit the design capacity.

The serially parallel connection member 80 is formed on the front surface of the second end plate 20. That is, the parallel and parallel connection member 80 is formed on the rear surface of the second manifold 70 ′ of the last unit cell 100 to be stacked.

The second parallel connection member 80 has a conductive plate 81 inserted in the center thereof, and a second manifold of the last unit cell 100 stacked on the front surface of the conductive plate 81 of the serial parallel connection member 80. The positive electrode and the negative electrode 71 and 71 'attached to the rear surface 70 may be in contact with each other.

In addition, although not shown in the drawings, the serial-to-parallel connection member is made of a conductive plate, and the positive electrode and the negative electrode attached to the rear surface of the second manifold of the last unit cell 100 stacked on the conductive plate are in contact with each other. Can be.

Although not shown in the drawing, the redox flow battery further includes a positive electrolyte tank for storing the positive electrolyte, a negative electrolyte tank for storing the negative electrolyte, and a pump for circulating the positive electrolyte and the negative electrolyte. In this case, the positive electrolyte and the negative electrolyte may be used without limitation. In particular, the redox flow battery may use an aqueous electrolyte solution, a non-aqueous electrolyte solution, an ionic liquid or a mixture thereof. In addition, the redox couple used in the positive electrolyte and the negative electrolyte may also be used without limitation to those generally used in the art.

10: first end plate 11,11 ': electrolyte injection hole
20: second end plate 21, 21 ': electrolyte outlet
30,30 ': positive electrode current collector, negative electrode current collector 40, 40': first manifold
41,41 ': positive electrode, negative electrode 42: groove
43,43 ', 73,73': anode reaction part, cathode reaction part
44,44 ', 74,74': Euro
50 felt electrode 60 gasket
65: separator 70, 70 ': second manifold
80: serial and parallel connection member 81: conductive plate
100: unit cell

Claims (13)

Redox flow battery, characterized in that it has a structure formed by stacking two or more unit cells including a manifold having a reaction portion having a different pole on one plate.
The method according to claim 1,
The redox flow battery includes a first end plate having an electrolyte injection hole, a second end plate having an electrolyte discharge hole, two current collectors having different poles as located on a rear surface of the first end plate, and the current collector. Redox flow battery, characterized in that it comprises a parallel connection member formed on the front side of the unit cell, and the second end plate to be laminated to the rear side.
The method according to claim 1,
The unit cell may include a first manifold having an anode electrode and a cathode electrode attached to one side thereof and having an anode reaction unit and a cathode reaction unit having polarities corresponding to the anode electrode and the cathode electrode on the other side thereof; A gasket including a separator formed at a position corresponding to the anode reaction part and the cathode reaction part; And a cathode reaction part and an anode reaction part having polarities opposite to the anode reaction part and the cathode reaction part of the first manifold at a position corresponding to the separator, and at one side of the cathode reaction part and the anode reaction part. It comprises a second manifold provided with a corresponding cathode electrode and anode electrode,
Redox flow battery, characterized in that the front surface of the first manifold of the other unit cell is located on the rear of the second manifold.
The method according to claim 1,
The positive electrode or the negative electrode formed on the rear surface of the second manifold is characterized in that consisting of a bipolar plate integrated in one play with the negative electrode or positive electrode formed on the front of the first manifold of the other unit cell Docs Flow Cell.
The method according to claim 3,
The positive electrode or the negative electrode is a redox flow battery, characterized in that made of a conductive graphite plate.
The method according to claim 3,
The positive electrode or the negative electrode is a redox flow battery, characterized in that the conductive graphite plate made of graphite impregnated with a phenol resin.
The method according to claim 3,
The positive electrode reaction portion comprises a flow path of the positive electrolyte, and the negative electrode reaction portion comprises a flow path of the negative electrolyte.
The method according to claim 3,
Redox flow battery, characterized in that the felt electrode is provided on both sides of the separator of the gasket.
The method according to claim 3,
Redox flow battery, characterized in that the manifold to which the positive electrode and the negative electrode is attached, a groove into which a portion of the positive electrode and the negative electrode is inserted.
The method according to claim 2,
The serial-parallel member is made of a conductive plate, and the positive electrode and the negative electrode attached to the rear surface of the second manifold of the last unit cell stacked on the conductive plate front, characterized in that the redox flow battery.
The method according to claim 2,
The parallel-parallel member includes a conductive plate inserted in the center thereof, and a positive electrode and a negative electrode attached to a rear surface of the second manifold of the last unit cell stacked on the front surface of the conductive plate of the parallel-parallel member are in contact with each other. Docs Flow Cell.
The method according to claim 1,
The positive electrode electrolyte or the negative electrode electrolyte is a redox flow battery, characterized in that used as an aqueous electrolyte, non-aqueous electrolyte, ionic liquid or a mixture thereof.
The method according to claim 1,
The redox flow battery comprises a positive electrolyte tank for storing a positive electrolyte, a negative electrolyte tank for storing a negative electrolyte and a pump for circulating the positive electrolyte and the negative electrolyte.

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