KR101291752B1 - Combined complex electrode cell with inner seal and redox flow battery comprising thereof - Google Patents

Abstract

PURPOSE: A redox flow battery is provided to prevent overflow of electrolyte to a bipolar plate, thereby reducing charging and discharging efficiency and reduction of energy efficiency. CONSTITUTION: A redox flow battery comprises a pair of end plates (1a,1b) each of which has an electrolyte inlet and outlet; a current collector (2a,2b) located on inner sides of the end plates; end manifolds (123,124) each of which has a bipolar plate mounted onto a side corresponding to the current collector, and an electrode inserted into the opposite side; and a composite electrode cell (140) which includes at least two separators (130), a first manifold with an outer side into which a first electrode is inserted, a second manifold with an outer side into which a second electrode is inserted, and a bipolar plate mounted between the first and second manifolds.

Description

Integrated composite electrode cell having an internal sealing structure and a redox flow battery including the same {COMBINED COMPLEX ELECTRODE CELL WITH INNER SEAL AND REDOX FLOW BATTERY COMPRISING THEREOF}

The present invention relates to an integrated composite electrode cell having an internal sealing structure and a redox flow battery including the same so as to prevent the electrolyte from falling over.

Redox flow battery (RFB) as a secondary battery for storage of large capacity power has low maintenance cost, can be operated at room temperature, and can be designed independently of capacity and output. Many studies have been conducted.

In general, a redox flow battery includes a positive electrode cell including a bipolar plate fixed to a frame and a positive electrode manifold having a positive felt electrode, and a negative electrode manifold equipped with a bipolar plate and a negative felt electrode fixed to a frame. And a separator formed between the cathode cell and the anode cell. The cathode and anode cells may be stacked in plural, and a current collector and an end plate may be placed on the outer surfaces of the outermost anode and cathode cells, respectively.

Such a conventional redox flow battery uses a bipolar plate frame that can support a bipolar plate in stacking, resulting in problems such as volume increase, price increase, and stacking time increase caused by using more materials.

Accordingly, the present inventors in the Korean Patent Application No. 2012-0099919 No. of the integrated composite electrode cell and the redox flow that can increase the stack stacking efficiency of the redox flow battery by reducing the stacking time and cost, stack price and volume A battery has been proposed. As shown in FIGS. 1A and 1B, the integrated composite electrode cell may include a first manifold in which a first electrode (hereinafter referred to as an anode electrode) may be inserted at an outer side, and a second electrode (hereinafter referred to as a cathode electrode for convenience). And a second manifold to be inserted, and a bipolar plate seated between the first and second manifolds.

In this case, the anolyte and the catholyte that are in contact with the cathode electrode of the first manifold and the cathode electrode of the second manifold, respectively, should be disconnected by the bipolar plate, but the phenomenon of crossing the surface of the bipolar plate to the opposite direction occurs. There is a problem. In particular, the bipolar plate using the graphite plate or carbon plate with good conductivity may cause the warpage phenomenon when laminated, it is required to prevent the fall of the electrolyte. Such a phenomenon of falling of the electrolyte may result in a decrease in charge and discharge efficiency and energy efficiency due to a long charging time or a short discharge.

Accordingly, the present invention is to solve the above-mentioned conventional problems, in order to integrate the bipolar plate inside the two manifolds of different polarities in order to significantly reduce the volume of the redox flow battery stack to increase the stacking efficiency. An integrated composite electrode cell which prevents the electrolyte from being in contact with the manifold on one side from passing through the surface of the bipolar plate to the manifold on the other side, so that the charging time is long or the discharge is shortened so as to reduce the charge and discharge efficiency and the energy efficiency. Its purpose is to provide a redox flow battery comprising the same.

In order to achieve the above object, an integrated composite electrode cell according to the present invention includes a first manifold in which a first electrode is inserted in an outer side, a second manifold in which a second electrode is inserted in an outer side, and a first manifold and a first manifold. And a bipolar plate seated in a seating groove provided inside the manifold, wherein at least one of the seating grooves of the first and second manifolds is provided with a leakage preventing unit for blocking leakage of electrolyte. do.

The lengths in the horizontal and vertical directions of the first and second electrodes may be smaller than the lengths in the horizontal and vertical directions of the bipolar plate.

The leakage preventing part may be formed by forming recesses in the recesses of the first manifold and the second manifold, respectively, and inserting a leakage preventing implant into the recess.

The leakage preventing unit may be made by attaching a leakage preventing implant to the seating grooves of the first and second manifolds.

In addition, the integrated composite electrode cell according to the present invention includes a first manifold in which a first electrode is inserted in an outer side, a second manifold in which a second electrode is inserted in an outer side, and a first manifold and a second manifold. And a bipolar plate seated in the seating groove, wherein a leakage preventing part is formed on at least one of the contact surfaces of the bipolar plate contacting the seating grooves of the first and second manifolds to prevent leakage of the electrolyte. do.

The lengths in the horizontal and vertical directions of the first and second electrodes may be smaller than the lengths in the horizontal and vertical directions of the bipolar plate.

The leakage preventing part may be formed by forming recesses in the contact surfaces of the bipolar plates that contact the seating grooves of the first and second manifolds, and inserting a leakproof implant into the recesses.

The leakage preventing part may be formed by attaching a leakage preventing implant to a contact surface of a bipolar plate contacting the seating grooves of the first and second manifolds.

The leak-proof implant may be made of a material selected from the group consisting of EPDM, Viton, rubber, soft PVC, rigid PVC.

The leak-proof implant may be manufactured in the form of a polygon or a circle.

Redox flow battery according to the present invention for achieving the above object is characterized in that it comprises at least one integral composite electrode cell.

The integrated composite electrode cell may be repeatedly stacked on the basis of the separator.

In addition, the redox flow battery according to the present invention corresponds to a pair of end plates having an electrolyte inlet and outlet, a current collector located inside each of the end plates, and located inside each of the current collectors. An end manifold in which a bipolar plate is seated on a side thereof and a felt electrode is inserted on an opposite side thereof, and an integrated composite electrode according to the present invention, which is positioned between the end manifold and at least two separators. Characterized in that it comprises a cell.

In the integrated composite electrode cell according to the present invention, the bipolar plate is seated between two manifolds to be integrated to remove the existing bipolar plate frame, thereby dramatically reducing the volume of the redox flow battery stack, thereby improving stacking efficiency. In addition to being able to increase, there is an advantage in that lamination can be facilitated.

In particular, in the integrated composite electrode cell according to the present invention, when the bipolar plate is inserted into two manifolds having different polarities and integrated, the electrolyte contacting the manifold on one side passes over the surface of the bipolar plate toward the manifold on the other side. It is possible to effectively prevent the charging and discharging efficiency and the energy efficiency from being lowered by prolonging the charging time or shortening the discharge due to the fall of the electrolyte.

Figure 1 shows a conventional integrated composite electrode cell, Figure 1a is an exploded perspective view, Figure 1b is a cross-sectional view of the coupling.
2 is a view schematically showing a laminated structure of a redox flow battery according to an embodiment of the present invention.
3 shows an integrated composite electrode cell according to an embodiment of the present invention. FIG. 3A is an exploded perspective view, FIG. 3B is an exploded cross-sectional view, and FIG. 3C is a combined cross-sectional view.
4 is an exploded cross-sectional view of an integrated composite electrode cell according to another exemplary embodiment of the present invention.
5 is an exploded cross-sectional view of an integrated composite electrode cell according to still another exemplary embodiment of the present invention.
6 is an exploded cross-sectional view of an integrated composite electrode cell according to still another embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

2 is a view schematically showing a laminated structure of a redox flow battery according to an embodiment of the present invention.

As shown in FIG. 2, the redox flow battery according to the present invention includes a pair of end plates 1a and 1b having electrolyte inlets and outlets, and a current collector disposed inside each of the end plates 1a and 1b. 2a, 2b) and an end manifold positioned inside each of the current collectors 2a and 2b, in which a bipolar plate 110 is seated on a surface corresponding to the current collectors 2a and 2b, and an electrode is inserted into an opposite surface. Located between the fold (123, 124) and the end manifold (123, 124) comprises at least two separation membrane 130 and the integral composite electrode cell 140 located between the separation membrane 130. .

The end plates 1a and 1b serve to form an outline of the entire redox flow battery, and are disposed at the outermost side, respectively, to form an electrolyte inlet and an electrolyte outlet, which are commonly used in the art. It can be easily formed by forming a passage that can be injected or discharged. Here, the electrolyte inlet and the electrolyte outlet are connected to the anode electrolyte tank and the cathode electrolyte tank, although not shown in the drawing, and the anode electrolyte and the cathode electrolyte are circulated by the driving of a separate pump.

The end plates 1a and 1b may be formed using an insulator. For example, the end plates 1a and 1b may be formed using polymers such as polyethylene (PE), polypropylene (PP), polystyrene (PS), and vinyl chloride (PVC), and can be easily used for price and ease of purchase. In consideration of this, it is preferable to form using vinyl chloride (PVC).

Current collectors 2a and 2b are formed inside each of the end plates 1a and 1b disposed at the outermost sides, and the current collectors 2a and 2b are passages through which electrons move and receive electrons from the outside during charging. It plays a role of emitting electrons to the outside during discharge. The two current collectors 2a and 2b located at both ends have electrodes different from each other.

The current collectors 2a and 2b are generally used in the art and are not particularly limited. For example, copper or brass may be used.

The end manifolds 123 and 124 are located inside each of the current collectors 2a and 2b, and the bipolar plate 110 is seated on a surface corresponding to the current collectors 2a and 2b, and the electrode is opposite to the current collectors 2a and 2b. Is inserted.

The bipolar plate 110 may use a conductive plate generally used in the art. Preferably, the bipolar plate 110 may use a conductive graphite plate. Preferably, the bipolar plate 110 may be a graphite plate impregnated in 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 electrode may provide an active site for redox of the electrolyte and may be used without limitation, which is generally used in the art. Preferably a felt electrode can be used.

For example, the felt electrode may be a nonwoven fabric, a carbon fiber, a carbon paper, or the like. Preferably, the felt electrode may be a carbon fiber felt electrode formed of polyacrylonitrile (PAN) or rayon (Rayon).

The end manifolds 123 and 124 may be used for the positive electrode or the negative electrode according to the position, and a flow path is formed on the surface on which the electrode is inserted, which is a passage for moving the positive or negative electrolyte according to the purpose.

According to the present invention, the end manifolds 123 and 124 include at least two separators 130 and an integrated composite electrode cell 140 positioned between the separators 130.

The separator 130 separates the positive and negative electrolytes during charging or discharging, and selectively moves only ions during charging or discharging. The separator 130 is generally used in the art and is not particularly limited.

Between the separators 130, the integrated composite electrode cell 140 according to the present invention is provided. In the conventional redox flow battery, the positive electrode manifold, the bipolar plate 110, and the negative electrode manifold are formed, respectively, In the integrated electrode cell 140 is provided. Details of the structure and the like of the composite electrode cell 140 will be described later.

The integrated composite electrode cell 140 may be repeatedly stacked based on the separator 130 according to the capacity of the redox flow battery. That is, the integrated composite electrode cell 140 and the separator 130 may be repeatedly stacked, and the number thereof is not limited and may be appropriately modified to suit the design capacity.

Although not shown in the drawings, the redox flow battery according to the present invention 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.

In addition, the negative electrode electrolyte and the positive electrode electrolyte may also be used in general, without limitation, which can also be easily implemented by those skilled in the art and a detailed description thereof will be omitted.

The integrated composite electrode cell 140 will be described in detail below.

3 shows an integrated composite electrode cell according to an embodiment of the present invention, FIG. 3A is an exploded perspective view, FIG. 3B is a cross-sectional view of the coupling, and FIG. 3C is an exploded cross-sectional view.

As shown in FIG. 3, the integrated composite electrode cell 140 according to the present invention includes a first manifold 121 in which the first electrode 125 is inserted at the outside, and a second in which the second electrode 126 is inserted in the outside. And a bipolar plate 110 seated in the mounting groove 141 provided inside the first manifold 121 and the second manifold 122, and the first manifold 121. ) And a leakage preventing part 142 is formed in at least one of the mounting grooves 141 of the second manifold 122 to block leakage of the electrolyte.

Since the same as the above-described bipolar plate 110 can be applied, a detailed description thereof will be omitted.

The bipolar plate 110 is seated in a mounting groove 141 formed between the first manifold 121 and the second manifold 122. As such, the bipolar plate is inserted into and fixed to the first manifold 121 and the second manifold 122 to remove the frame of the bipolar plate 110.

The bipolar plate 110 may be seated in the seating groove 141 through adhesive or heat fusion. The bipolar plate 110 is fixed to the mounting groove 141 inside the first manifold 121 and the second manifold 122, so that the bipolar plate 110 can be fixed without the bipolar plate 110 frame.

Therefore, by removing the conventional bipolar plate 110 frame can reduce the cost required for manufacturing, it is possible to prevent leakage due to the conventional flatness difference and staggering phenomenon. Most of all, the volume of the stack can be reduced to provide a redox flow cell structure with increased capacity of redox flow cells per volume. In addition, the lamination can be easily performed to shorten the working time.

The first electrode 125 or the second electrode 126 is inserted into the first and second manifolds 121 and 122. As the first electrode 125 and the second electrode 126, a felt electrode as described above may be used. However, the first electrode 125 and the second electrode 126 may be divided into positive or negative electrodes having different polarities according to the positive or negative electrolyte.

In this case, the lengths of the first electrode 125 and the second electrode 126 in the horizontal and vertical directions are smaller than the lengths of the bipolar plate 110 in the horizontal and vertical directions. That is, the sizes of the first electrode 125 and the second electrode 126 are smaller than the bipolar plate 110.

A flow path is provided on the surfaces of the first manifold 121 and the second manifold 122 into which the first electrode 125 or the second electrode 126 is inserted. The flow path is a passage for moving the electrolyte, and the positive electrolyte or the negative electrolyte is moved, the shape of which can be variously modified. In addition, the first manifold 121 and the second manifold 122 may be provided with an inlet and an outlet for supplying or discharging the positive electrolyte solution or the negative electrolyte solution to the flow passage, which can be easily formed by those skilled in the art. It is possible.

According to the present invention, a leakage preventing part 142 is formed in at least one of the mounting grooves 141 of the first manifold 121 and the second manifold 122 to block the leakage of the electrolyte. The leakage preventing part 142 prevents the positive electrolyte and the negative electrolyte from contacting the first manifold 121 and the second manifold 122 to pass in the opposite direction on the surface of the bipolar plate 110. It is for.

In order to effectively prevent leakage of the electrolyte, the leakage preventing part 142 may be formed in the mounting grooves 141 of the first manifold 121 and the second manifold 122, respectively.

For example, the leakage preventing part 142 is formed by attaching a leakage preventing implant to the contact surface of the bipolar plate 110 in contact with the mounting groove 141 of the first manifold 121 and the second manifold 122. It may be.

The leakage preventing implant applied to the leakage preventing part 142 may be made of a material selected from the group including EPDM, Viton, rubber, soft PVC, and rigid PVC.

When the leakage preventing unit 142 is applied to the integrated composite electrode cell 140 according to the present invention as described above when the bipolar plate 110 is inserted into the two manifolds (121, 122) of different polarity to integrate The electrolyte preventing contact with the manifold on one side by the leakage preventing part 142 does not cross the surface of the bipolar plate 110 toward the manifold on the other side. It becomes short, and can effectively prevent a fall of charging / discharging efficiency and energy efficiency.

The leak prevention part 142 may be modified in various shapes.

4 to 6 are exploded cross-sectional views of the integrated composite electrode cell according to another embodiment of the present invention, as shown in FIGS. 4 to 6 are applied to the integrated composite electrode cell 140 according to another embodiment of the present invention. The leakage preventing part 142 may be formed by forming recesses in the seating grooves 141 of the first manifold 121 and the second manifold 122, respectively, and inserting a leakage preventing implant into the recesses.

In this case, the leakage preventing part 142 may be formed by inserting one or more o-rings or two or more o-ring leakage preventing implants into the recesses of the seating grooves 141. In addition, as shown in the drawings, the leakage preventing prosthesis of the leakage preventing part 142 may have various shapes such as a cross section and a circular shape.

According to the present invention, although not illustrated in detail, the leakage preventing part 142 is a bipolar plate 110 in contact with the mounting groove 141 of the first manifold 121 and the second manifold 122. It may be formed on at least one of the contact surfaces. This is because the above-described leak prevention part 142 is formed in the seating groove 141 of the first manifold 121 and the second manifold 122, the bipolar plate 110 in contact with the seating groove 141. It is formed on the contact surface of, except for this will have the same structure, so a detailed description thereof will be omitted.

<Experimental Example>

In order to confirm the fall of the positive electrolyte and the negative electrolyte through the bipolar plate (GCP), a form of a redox flow battery as shown in FIG. 2 was configured. However, in order to exclude the phenomenon that the electrolyte flows through the separator, hard PVC without pores was used instead of the separator. 5 mm graphite fiber was used as an electrode, and the cell was cut | disconnected by the area of 30 cm <^2> . In this case, as shown in FIG. 4, the integrated composite electrode cell has one O-ring formed in each of the first and second manifolds.

In addition, a cathode electrolyte tank, a cathode electrolyte tank, and a pump for transporting the electrolyte were prepared to enable the electrolyte flow of the redox flow battery. In the cathode electrolyte tank, 2 mol of vanadium was dissolved in 2 mol of sulfuric acid solution to dissolve the blue vanadium tetravalent. The electrolyte solution was injected, and 2 mol of sulfuric acid aqueous solution was injected into the cathode electrolyte tank. Each 80ml of the electrolyte was injected, and the electrolyte was poured into the laminate at a flow rate of 80ml per minute using a pump.

At this time, the change of electrolyte level with time was observed, and the absorbance was confirmed by using an absorbance meter (UV / Vis spectrometer Lambda2) of PERKIN ELMER. In order to confirm the absorbance, 2 ml of the negative electrolyte was collected and the absorbance change was measured. After the measurement, the absorbance was again injected into the negative electrolyte tank to proceed without affecting the water level.

The prepared tetravalent vanadium sulfuric acid aqueous solution exhibited a maximum absorption wavelength at 760 nm, and the absorbance change generated as the electrolyte was crossed by collecting the negative electrolyte without tetravalent vanadium was observed.

As a result, as shown in Table 1, no change in the level and absorbance of the negative electrolyte was occurred during the 200-hour experiment. This means that there is no leakage of electrolyte through the electrode, so that the inside of the electrode is well sealed.

Time change [hr] Cathode Electrolyte Level [ml] Catholyte
Absorbance change 0 80 none One 80 none 5 80 none 10 80 none 20 80 none 40 80 none 60 80 none 80 80 none 100 80 none 120 80 none 140 80 none 160 80 none 180 80 none 200 80 none

As described above, the integrated composite electrode cell in which the leakage preventing unit is formed according to the present invention can prevent the electrolyte from falling due to the bipolar plate seated between the first manifold and the second manifold, thereby charging and discharging efficiency and energy efficiency. It can prevent the decrease.

Although the present invention has been described with reference to the accompanying drawings as an example, it is presented to aid the understanding of the present invention, the present invention is not limited thereto, and those skilled in the art will understand that various changes and modifications can be made therefrom. Could be. Accordingly, the invention encompasses all such alternatives, modifications and variations that fall within the spirit and scope of the appended claims.

1a, 1b: end plate 2a, 2b: current collector
110: bipolar plate 121: the first manifold
122: second manifold 123, 124: end manifold
125: first electrode 126: second electrode
130: separator 140: integrated electrode cell
141: seating groove 142: leak prevention unit

Claims (6)

A pair of end plates having an electrolyte inlet and an outlet,
A current collector located inside each of the end plates,
An end manifold, which is located inside each of the current collectors, on which a bipolar plate is seated on a surface corresponding to the current collector, and an electrode is inserted on an opposite surface;
A first manifold formed between the at least two separators and the separator and having a first electrode inserted therein, a second manifold having a second electrode inserted outside thereof, and the first manifold positioned between the end manifolds; An integrated composite electrode cell including a bipolar plate seated between the manifold and the second manifold,
The end plate is formed using any one of polyethylene (PE), polypropylene (PP), polystyrene (PS) and vinyl chloride (PVC),
The bipolar plate is formed using a conductive graphite plate impregnated with a phenol resin,
The electrode is formed of polyacrylonitrile-based fibers or Rayon-based fibers,
Redox flow battery, characterized in that the leakage preventing portion for blocking the leakage of the electrolyte is formed in the mounting groove provided in at least one manifold of the first manifold and the second manifold of the integrated electrode cell. A pair of end plates having an electrolyte inlet and an outlet,
A current collector located inside each of the end plates,
An end manifold, which is located inside each of the current collectors, on which a bipolar plate is seated on a surface corresponding to the current collector, and an electrode is inserted on an opposite surface;
A first manifold formed between the at least two separators and the separator and having a first electrode inserted therein, a second manifold having a second electrode inserted outside thereof, and the first manifold positioned between the end manifolds; An integrated composite electrode cell including a bipolar plate seated between the manifold and the second manifold,
The end plate is formed using any one of polyethylene (PE), polypropylene (PP), polystyrene (PS) and vinyl chloride (PVC),
The bipolar plate is formed using a conductive graphite plate impregnated with a phenol resin,
The electrode is formed of polyacrylonitrile-based fibers or Rayon-based fibers,
Redox flow battery, characterized in that the leakage preventing portion for blocking the leakage of the electrolyte is formed on the contact groove contact surface of the bipolar plate of the integrated electrode cell. The method according to claim 1 or 2,
Redox flow battery, characterized in that the leak-proof implant is made of a material selected from the group consisting of EPDM, Viton, rubber, soft PVC, rigid PVC. The method according to claim 1 or 2,
Redox flow battery, characterized in that the leakage preventing portion of the integrated composite electrode cell is polygonal or circular. delete delete

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