KR101742486B1 - Flow flame having variable channel and redox flow secondary battery comprising the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow frame having a variable channel and a redox flow secondary battery including the same, and is intended to improve the generation of shunt current while simplifying the flow path structure. The flow frame according to the present invention includes a frame body having an electrode insertion hole in which an electrode is installed at a central portion, an injection flow path portion formed in a frame body on one side of the electrode to inject an electrolyte into the electrode, And an outflow channel portion formed on a frame body of the other opposing side to discharge electrolyte from the electrode. The injection path portion and the outflow path portion each include a manifold formed in the frame body and a plurality of channels connecting the manifold and the electrode insertion hole. The plurality of channels are different in cross-sectional area and length.

Description

[0001] The present invention relates to a flow frame having a variable channel and a redox flow secondary battery including the flow frame,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a redox flow secondary battery, and more particularly, to a redox flow secondary battery having a flow path structure of a flow frame, To a flow frame having a variable channel that improves the generation of a shunt current and simplifies a flow path structure, and a redox flow secondary battery including the flow frame.

Redox Flow Redox in secondary batteries is a term synthesized by reducing Reduction and Oxidation. The redox flow secondary battery is a secondary battery of a system in which a solution of two kinds of redox couples, which are active materials, reacts at the anode and the cathode. The redox flow secondary battery is a battery for supplying and discharging the redox couple solution from the outside of the battery cell. As the redox couple, Fe / Cr, V / Br, Zn / Br, Zn / Ce and V / V are used.

The redox flow secondary battery can be included in the fuel cell in that it is a battery that operates by continuously supplying a reactant from outside the battery cell. And because the charge can be discharged, the redox flow secondary battery can be classified as an electric regenerative fuel cell.

The redox flow secondary battery has the advantage of stacking a plurality of unit cells and stacking them. However, since a redox flow secondary battery uses an electrolyte having a high ion conductivity, a shunt current is unconditionally generated due to the formation of an electrical path through an electrolyte through a flow frame.

The reason why the shunt current is generated will be described as follows. The redox flow rechargeable battery is mainly used as an emergency power supply. As a result, the redox flow rechargeable battery is kept in a charged state and operated in an emergency, so that the standby time may become longer. When the waiting time of the charged redox flow secondary battery becomes long, a shunt current is generated. That is, when the standby time of the redox flow secondary battery becomes long, the active material dissolved in the electrolyte existing in the unit cells of the stack moves to the opposite side through the separation membrane, and an electrochemical reaction occurs and self-discharge occurs. In addition, when a large amount of electrolytic solution remaining in the channel (piping), which is an electrolytic solution moving passage installed to supply the electrolytic solution to the unit cell, is diffused into the stack, more self-discharge occurs. In order to charge the discharged electrolyte again, energy must be applied again, so that power loss can not be avoided.

Particularly, as the number of unit cells increases with the passage of the electrolyte after the stacking, the shunt current increases, which is recognized as a limiting factor of the number of unit cells stacked as well as the energy efficiency.

In order to solve this problem, a simple manifold and flow channel structure is used for the flow frame used in the redox flow rechargeable battery to keep the flow rate distribution constant and minimize the pressure loss. However, there is a limitation in improving the shunt current in the flow path structure of the conventional flow frame.

Korean Patent No. 10-1291753 (Jul. 25, 2013)

In order to minimize the conventional shunt current, the flow channel has been designed to maximize the shunt resistance by shortening the cross-sectional area of the flow channel and increasing the length of the flow channel, but it is not yet sufficient. In addition, the flow path structure maximizing the shunt resistance has limitations in improving the flow uniformity of the electrolyte and the pressure loss. In addition, since the channel structure maximizing the shunt resistance requires a complicated and long channel structure, it is a limiting factor in designing the channel structure in the flow frame.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a flow frame having a variable channel that simplifies a flow path structure by varying a cross-sectional area and a length of channels forming the flow path of the flow frame, and a redox flow secondary battery including the flow frame.

It is another object of the present invention to provide a flow frame having a variable channel for minimizing flow uniformity and pressure loss of an electrolyte through variable channels through the introduction of a variable channel having a different cross-sectional area and length, And a re-flowable secondary battery.

In order to attain the above object, the present invention provides a flow frame for a redox flow secondary battery including a frame body, an injection path portion and an outflow path portion. The frame body is formed with an electrode insertion hole in which an electrode is provided at a central portion thereof. The injection path portion is formed in the frame body on one side of the electrode insertion hole, and injects the electrolyte into the electrode insertion hole. The outflow channel portion is formed in the frame body on the other side facing the one side with respect to the electrode insertion hole, and the electrolyte solution flows out from the electrode insertion hole.

The injection path portion and the outflow path portion each include a manifold and a plurality of channels. The manifold is formed through the frame body. The plurality of channels are formed in the frame body, one end is connected to the manifold, and the other end is connected to one side of the electrode insertion hole, and has a different cross-sectional area and length.

In the flow frame according to the present invention, the cross-sectional area and the length may increase as the distance from the plurality of channels to the point where the manifold is connected to the electrode insertion hole increases.

In the flow frame according to the present invention, the electrode insertion hole may have a rectangular tube shape. The manifold may be formed on one side edge of the electrode insertion hole. The plurality of channels may include a horizontal horizontal channel part on one side of the electrode insertion hole and a vertical channel part connecting the horizontal channel part and one side of the electrode insertion hole in a vertical direction.

In the flow frame according to the present invention, the plurality of channels may include a main channel, a branching unit, and a plurality of branch channels. The main channel is formed in the frame body, has one end connected to the manifold, and has a smaller inner diameter than the manifold. The branch tank is formed in the frame body and has an inner space connected to the other end of the main channel and larger than an inner diameter of the main channel. The plurality of branch channels are formed in the frame body, one end thereof is connected to the branch bank, and the other end is connected to one side of the electrode insertion hole, and has an inner diameter smaller than that of the main channel.

In the flow frame according to the present invention, the cross sectional area and the length may increase as the distance from the branch channel to the point where it is connected to the electrode insertion hole is increased.

In the flow frame according to the present invention, the branch tank may have a circular or elliptical cross section, and the inner diameter may be 10 times or less the inner diameter of the main channel.

In the flow frame according to the present invention, the injection path portion and the manifold portion of the outflow path portion may be formed at one of corners opposite to each other with respect to the electrode insertion hole and one of diagonal corners.

The present invention also provides a redox flow secondary battery including a plurality of unit cells each having the above-described flow frame and a plurality of bipolar plates. The plurality of unit cells may include a separator, a first electrode and a second electrode disposed opposite to each other with the separator interposed therebetween, and an electrolyte solution is flowed to the first and second electrodes through the first electrode and the second electrode, The stack has stacked first and second flow frames. The plurality of bipolar plates are interposed between the plurality of unit cells and stacked on both sides of the plurality of stacked unit cells.

According to the present invention, by designing the plurality of channels to have the same length and cross-sectional area by differentiating the cross-sectional area and the length of the plurality of channels connected to the manifold, the flow path structure formed in the flow frame can be simplified. As a result, the area occupied by the flow path in the flow frame can be reduced, so that the channel portion can be made compact.

Also, the generation of shunt current can be minimized by minimizing the flow uniformity and pressure loss of the electrolyte through the introduction of a variable channel having different cross-sectional areas and lengths of channels.

Further, by improving the flow rate uniformity of the electrolytic solution, the flow rate distribution of the electrolytic solution can be improved, so that the stack stability of the unit cells can be improved. As a result, the stack stability of the unit cells can be improved, so that the number of unit cells stacked in the redox flow secondary battery can be increased and the serial connection characteristic can be expanded.

In addition, by increasing the number of stacked unit cells and increasing the series connection characteristic, it is possible to realize a high voltage of the redox flow secondary battery.

Further, by configuring the flow path structure in the flow frame to be a main channel and a plurality of branch channels, the generation of the shunt current can be minimized by increasing the shunt resistance. That is, by designing the branch points branching from the main channel to the plurality of branch channels in a circular or oval shape, the flow rate uniformity of the electrolyte can be improved and the pressure loss can be minimized to improve the efficiency of the redox flow secondary battery.

Of course, the branch channels connected to each other via the branch points can be simplified in terms of the cross-sectional area and the length, thereby simplifying the flow path structure formed in the flow frame.

1 is a view illustrating a redox flow secondary battery having one unit cell according to a first embodiment of the present invention.
2 is a view illustrating a redox flow secondary battery having a plurality of unit cells according to a first embodiment of the present invention.
3 is a plan view showing a flow frame of a unit cell according to a first comparative example.
4 is a plan view showing a flow frame of a unit cell according to the first embodiment of the present invention.
5 is a plan view showing a flow frame of a unit cell according to a second embodiment of the present invention.
6 is a plan view showing a flow frame of a unit cell according to a third embodiment of the present invention.

In the following description, only parts necessary for understanding embodiments of the present invention will be described, and descriptions of other parts will be omitted to the extent that they do not disturb the gist of the present invention.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and the inventor is not limited to the meaning of the terms in order to describe his invention in the best way. It should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely preferred embodiments of the present invention, and are not intended to represent all of the technical ideas of the present invention, so that various equivalents And variations are possible.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First Embodiment

1 is a view illustrating a redox flow secondary battery having one unit cell according to a first embodiment of the present invention.

1, the redox flow rechargeable battery 100 according to the first embodiment includes a unit cell 10 and a pair of bipolar plates 61 and 69 bonded to both sides of the unit cell 10 The first and second current collectors 71 and 79, the first and second cell frames 81 and 89, and the first and second cell frames 81 and 89, which are sequentially disposed outside the pair of bipolar plates 61 and 69, Electrolyte tanks 91 and 96, and first and second pumps 92 and 97, respectively.

The unit cell 10 includes a separation membrane 11, a first electrode 13, a second electrode 15, a first flow frame 20 and a second flow frame 50. A first electrode (13) and a second electrode (15) are disposed facing each other with a separator (11) therebetween. The first and second flow frames 20 and 50 are respectively connected to the first electrode 13 and the second electrode 15 to flow the electrolyte solution into the first and second electrodes 15 and 15. The first electrode 13 and the second electrode 15 are electrodes having opposite polarities. For example, the first electrode 13 may be an anode and the second electrode 15 may be a cathode.

At this time, the separator 11 separates the first electrolyte and the second electrolyte from each other during charging or discharging, and selectively moves ions only during charging or discharging. Such a separation membrane 11 is not particularly limited as it is generally used.

The first and second electrodes 13 and 15 provide active sites for the oxidation of the first and second electrolytes, respectively. As the first and second electrodes 13 and 15, a felt electrode may be used. For example, as the material of the first and second electrodes 13 and 15, nonwoven fabric, carbon fiber, carbon paper, or the like may be used, but the present invention is not limited thereto. Preferably, the first and second electrodes 13 and 15 may be carbon felt electrodes formed of polyacrylonitrile (PAN) or rayon (Rayon) series.

The first and second flow frames 20 and 50 have a first electrode insertion hole 27 and a second electrode insertion hole 57 through which the first electrode 13 and the second electrode 15 are inserted, Respectively. The first and second flow frames 20 and 50 are formed by flowing the first electrolyte and the second electrolyte through the first and second electrodes 15 inserted into the first and second electrode insertion holes 27 and 27, And the like. Plastic materials such as polyethylene (PE), polypropylene (PP), polystyrene (PS), or vinyl chloride (PVC) may be used as the material of the first and second flow frames 20 and 50, It is not. On the other hand, in the redox flow secondary battery 100 according to the first embodiment, since the flow path structure formed in the first and second flow frames 20 and 50 has a technical feature, the first and second flow frames 20 and 50 ) Will be described later.

In the redox flow secondary battery 100, a redox couple generally used as the first electrolyte and the second electrolyte may be used. For example, the first electrolyte may use a V ⁴⁺ / V ⁵⁺ couple as a redox couple, and the second electrolyte may use a V ²⁺ / V ³⁺ couple as a redox couple.

A pair of bipolar plates (61, 69) are stacked on the outside of the first and second flow frames (20, 50). As the bipolar plates 61 and 69, a conductive plate may be used. A conductive graphite plate may be used as the material of the bipolar plates 61 and 69. For example, the bipolar plate 61, 69 may be a graphite plate impregnated with phenolic resin. When the graphite plate is used solely as the bipolar plates 61 and 69, the strong acid used in the electrolytic solution can permeate the graphite plate. Therefore, it is preferable to use a graphite plate impregnated with a phenol resin in order to prevent permeation of strong acid in the bipolar plates 61 and 69

In the first electrode 13 inserted into the first electrode insertion hole 27 of the first flow frame 20, the first electrode 13 exposed to the outside through the first electrode insertion hole 27 Both surfaces are in contact with the separation membrane 11 and the bipolar plates 61 and 69, respectively. Between the separation membrane 11 and the first flow frame 20 or between the separator 11 and the first flow frame 20 in order to suppress leakage of the first electrolyte through the interface between the separation membrane 11, the first flow frame 20 and the bipolar plates 61, A gasket may be interposed between the first flow frame 20 and the bipolar plate 61.

In the second electrode 15 inserted into the second electrode insertion hole 57 of the second flow frame 50, the distance between the second electrode 15 exposed to the outside through the second electrode insertion hole 57 Both surfaces are in contact with the separation membrane 11 and the bipolar plates 61 and 69, respectively. Between the separation membrane 11 and the second flow frame 50 or between the separator 11 and the second flow frame 50 in order to suppress leakage of the second electrolyte through the interface between the separation membrane 11 and the second flow frame 50 and the bipolar plates 61, A gasket may be interposed between the second flow frame 50 and the bipolar plates 61, 69.

First and second current collectors 71 and 79 are stacked on the outside of the pair of bipolar plates 61 and 69. The first and second current collectors 71 and 79 serve as a passage through which electrons move, and serve to receive electrons from the outside when charging or to emit electrons to the outside when discharging. The first and second current collectors 71 and 79 may be made of a conductive metal plate made of copper or brass.

The first and second cell frames 81 and 89 are coupled to the outside of the first and second current collectors 71 and 79. The first and second cell frames 81 and 89 fix the unit cell 10, the pair of bipolar plates 61 and 69, and the first and second current collectors 71 and 79 interposed therebetween. The first and second cell frames 81 and 89 are formed with an injection port and an outflow port for injecting or discharging the first and second electrolytic solutions into the first and second flow frames 20 and 50 of the unit cell 10, have. As the material of the first and second cell frames 81 and 89, an insulator may be used. For example, polyethylene (PE), polypropylene (PP), polystyrene (PS), vinyl chloride (PVC), or the like may be used as the material of the first and second cell frames 81 and 89, .

The first electrolyte tank 91 has a first inlet pipe 93 and a first outlet pipe 94 connected to an inlet and an outlet formed in the first cell frame 81 to connect the first electrolyte to the first cell frame 81 ). At this time, a first pump 92 for circulating the first electrolyte is connected to the first inlet pipe 93.

In the second electrolyte tank 96, the second inlet pipe 98 and the second outlet pipe 99 are connected to the inlet and outlet of the second cell frame 81 and 89, respectively, And is circulated to the frame 89. At this time, a second pump 97 for circulating the second electrolyte is connected to the second inlet pipe 98.

The redox flow secondary battery 100 according to the first embodiment circulates the first and second electrolytic solutions as follows. That is, the first electrolytic solution drawn out from the first electrolyte tank 91 is injected into the inlet of the first cell frame 81 through the first inlet pipe 93 by the operation of the first pump 92. The first electrolyte injected into the inlet of the first cell frame 81 passes through the first current collector 71 and the first bipolar plate 61 and flows through the first flow frame 20 of the unit cell 10 to the first Passes through the electrode (13). The first electrolyte 13 passes through the outlet of the first flow frame 20, the first bipolar plate 61, the second current collector 79 and the first cell frame 81, 1 outflow pipe (94). The first electrolytic solution flowing out to the first outflow pipe (94) enters the first electrolyte tank (91).

The second electrolytic solution drawn out from the second electrolyte tank 96 is injected into the inlet of the second cell frame 89 through the second inlet pipe 98 by the operation of the second pump 97. The second electrolyte injected into the inlet of the second cell frame 89 passes through the second current collector 79 and the second bipolar plate 69 and flows through the second flow frame 50 of the unit cell 10, And passes through the electrode 15. The second electrolyte 15 having passed through the second electrode 15 passes through the outlet of the second flow frame 50, the second bipolar plate 69, the second current collector 79 and the second cell frame 89, 2 outflow pipe (99). The second electrolyte discharged from the second outflow pipe (99) enters the second electrolyte tank (96).

On the other hand, FIG. 1 shows an example in which the redox flow secondary battery 100 includes one unit cell 10, but the present invention is not limited thereto. That is, as shown in FIG. 2, the redox flow secondary battery 200 may have a structure in which a plurality of unit cells 10 are stacked.

2 is a view showing a redox flow secondary battery 200 having a plurality of unit cells 10 according to a first embodiment of the present invention.

Referring to FIG. 2, the redox flow secondary battery 200 includes a bipolar plate 60 interposed between a plurality of unit cells 10, a pair of bipolar plates 60 on both sides of the stacked unit cells 10, Except for the structure in which the plate 60 is disposed, as in the redox flow secondary battery 100 of FIG. That is, the redox flow secondary battery 200 includes first and second current collectors 71 and 79, a pair of second current collectors 71 and 79, and a pair of second current collectors 71 and 79 on a pair of bipolar plates 61 and 69 located on both sides of the stacked unit cells 10, 1 and the second cell frames 81 and 89, and the first and second electrolyte tanks 91 and 96 are connected.

On the other hand, the redox flow rechargeable battery 200 according to FIG. 2 has disclosed an example in which three unit cells 10 are stacked, but the present invention is not limited thereto. That is, two or more unit cells 10 may be stacked to implement a redox flow secondary battery.

Meanwhile, in order to improve the shunt current of the redox flow rechargeable battery, as shown in FIG. 3, flow frames 320 and 350 using a channel design applying a plurality of channels 336 having a narrow width and a long length have been developed . 3 is a plan view showing flow frames 320 and 350 of a unit cell according to a first comparative example.

Referring to FIG. 3, a redox flow secondary battery is constructed using flow frames 320 and 350 having a single structure in which a plurality of channels 336 are connected to a manifold 331.

That is, the flow frames 320 and 350 include a frame body 321, an injection flow path portion 323, and an outlet flow path portion. In the frame body 321, electrode insertion holes 327 and 357 through which electrodes are inserted are formed in the center portion. The injection flow path portion 323 is formed in the frame body 321 on one side of the electrode insertion holes 327 and 357 and injects the electrolyte into the electrode insertion holes 327 and 357. The outflow channel portion is formed on the other frame body 321 facing the one side with respect to the electrode insertion holes 327 and 357 to discharge the electrolyte solution from the electrode insertion holes 327 and 357.

At this time, the injection path portion 323 includes a first manifold 331 and a plurality of first channels 336. Although not shown, the outflow channel 325 includes a second manifold 431 and a plurality of second channels 436.

However, the channel design of the flow frames 320 and 350 according to the first comparative example has a disadvantage in that the channel model is complicated by applying a plurality of channels 336 and 436 having the same cross-sectional area and length. That is, since the plurality of channels 336 and 436 have the same length, the number of bent portions increases as the distance from the first and second manifolds 331 and 431 to the point of connection to the electrode insertion holes 327 and 357 becomes closer , The flow path model is complicated and the area occupied by the injection flow path portion 323 and the flow path portion 325 in the flow frames 320 and 350 becomes large.

In the present invention, a geometric relation as expressed by Equation 2 can be obtained by using the pressure loss relation equation of the fluid as shown in the following Equation 1. Equation (2) is a relational expression for the length (1) and the diameter (D) of the channel with respect to DELTA p.

[Equation 1]

Since Q = const = VA, V = C3 / D and f = 64 / Re = 64v / VD in the laminar flow region.

&Quot; (2) "

Δp: pressure loss

D: Diameter

l: length (length)

V: Mean Velocity to Area (A)

ρ: Density

Q: volumetric fluid

f: coefficient of friction

υ: Average flow rate in the channel

Re: Reynolds number of the flow

ρV ^2/2: the unit kinetic energy (kinetic energy per unit volume) per volume

Using the geometric relationship of the channels, the present invention simplifies the existing complex channel structure by changing the cross-sectional area and length of each channel.

The flow frames 20 and 50 of the unit cell 10 applied to the redox flow secondary battery 100 according to the first embodiment will now be described with reference to FIGS. 1, 2 and 4. FIG. 4 is a plan view showing flow frames 20 and 50 of the unit cell 10 according to the first embodiment of the present invention.

1, 2 and 4, the flow frames 20 and 50 include a frame body 21, an injection flow passage portion 23, and an outlet flow passage portion 25. The frame body 21 is formed with electrode insertion holes 27 and 57 through which the electrodes 13 and 15 are inserted. The injection flow path portion 23 is formed in the frame body 21 on one side of the electrode insertion holes 27 and 57 and injects the electrolyte into the electrode insertion holes 27 and 57. The outflow channel portion 25 is formed on the other frame body 21 facing the one side with the electrode insertion holes 27 and 57 as a center, and discharges the electrolyte solution from the electrode insertion holes 27 and 57.

In this case, the flow frames 20 and 50 according to the first embodiment have an example in which the injection flow channel portion 23 is formed on the upper portion of the electrode insertion holes 27 and 57 and the outflow channel portion 25 is formed on the lower portion thereof However, the present invention is not limited to this. For example, the flow frames 20 and 50 may have an injection flow channel portion 23 formed at a lower portion with the electrode insertion holes 27 and 57 as a center, and an outflow channel portion 25 formed at an upper portion thereof.

One side of the electrode insertion holes 27 and 57 on which the injection flow path portion 23 is provided and the other side of the electrode insertion holes 27 and 57 on which the flow path portion 25 is provided are provided with electrode insertion holes 27 and 57 Microinjection flow paths 17 and microextraction flow paths 19 are formed so that the electrolytic solution can flow uniformly throughout. The inflow channel portion 23, the outflow channel portion 25, the microfluidic channel 17 and the microfluidic channel 19 are formed in a negative shape on one side of the frame body 21, respectively.

At this time, the frame body 21 forms a contour of the flow frames 20 and 50, and may be formed in a shape close to, for example, a rectangular plate. As the material of the frame body 21, a plastic resin such as polyethylene (PE), polypropylene (PP), polystyrene (PS), or vinyl chloride (PVC) may be used.

The injection flow path portion 23 includes a first manifold 31 and a plurality of first channels 36. The outflow channel portion 25 includes a second manifold 41 and a plurality of second channels 46.

Since the injection path portion 23 and the outflow path portion 25 have the same configuration, the description will be made with reference to the injection path portion 23 as follows. The injection path portion 23 and the outflow path portion 25 are formed symmetrically up and down about the electrode insertion holes 27 and 57.

The first manifold 31 is formed to penetrate the frame body 21. The plurality of first channels 36 are formed in the frame body 21 and have one end connected to the first manifold 31 and the other end connected to one side of the electrode insertion holes 27 and 57, .

The first manifold 31 is connected to the injection port of the cell frame. The second manifold 41 is connected to the outlet of the cell frame. The electrolyte solution in the electrolyte tank is supplied to the electrode insertion holes 27 and 57 through the first manifold 31 through the inlet of the cell frame and the electrolyte solution passing through the electrode insertion holes 27 and 57 Is returned to the electrolyte tank through the outlet of the cell frame through the second manifold (41). The first manifold 31 and the second manifold 41 may be formed on the opposite sides of the electrode insertion holes 27 and 57 facing each other.

The first manifold 31 may be formed at one side edge of the electrode insertion holes 27 and 57 when the electrode insertion holes 27 and 57 are in the form of a rectangular tube.

The plurality of first channels 36 are connected at one end to the first manifold 31 and at the other end to different points on one side of the electrode insertion holes 27, In other words, the other ends of the plurality of first channels 36 are connected to different points of the micro-injection channel 17 formed on one side of the electrode insertion holes 27 and 57. One side of the electrode insertion holes 27 and 57 to which the plurality of first channels 36 are connected is a side surface of the electrode insertion holes 27 and 57 located on the side where the injection flow path portion 23 is formed.

The plurality of first channels 36 are connected to the electrode insertion holes 27 and 57 around the first manifold 31 so that the electrolyte can be uniformly and uniformly injected into the electrode insertion holes 27 and 57 through the micro- Sectional area and length increases as the distance to the point of connection to the first and second ends (27, 57) increases. The reason why the plurality of first channels 36 are formed in this manner is that the pressure loss can be minimized by securing the same DELTA p.

That is, the plurality of first channels 36 include horizontal horizontal channel portions 36a on one side of the electrode insertion holes 27 and 57, horizontal channels 36a on one side of the horizontal channel portion 36a and electrode insertion holes 27 and 57, And a vertical channel portion 36b for connecting the vertical channel portions 36a and 36b in the vertical direction. That is, the plurality of first channels 36 may be simply formed as a translator having a single bent portion.

For example, although the injection path portion 23 according to the first embodiment has five first channels, it is not limited thereto. That is, the number of the first channels can be changed according to the size of the electrode insertion holes 27 and 57.

In order that the flow rate of the electrolytic solution flowing into the electrode insertion holes 27 and 57 through the injection flow path portion 23 can be supplied to one side of the electrode insertion holes 27 and 57 as a whole at the same speed, Sectional area of the first manifold 31 and the cross-sectional area of the first manifold 31 in a one-to-one relationship so that there is no pressure difference. In order to allow the flow rate of the electrolytic solution flowing out from the electrode insertion holes 27 and 57 to flow out to the other side of the electrode insertion holes 27 and 57 at the same speed as the whole, It is preferable that the cross-sectional area of the second manifold 41 is one-to-one so that there is no pressure difference.

As described above, the flow frames 20 and 50 according to the first embodiment have different cross sectional areas and lengths of the plurality of channels 36 and 46 connected to the manifolds 31 and 41, The flow path structure to be formed can be simplified. Therefore, the area occupied by the flow path in the flow frames 20 and 50 can be reduced, so that the area occupied by the injection path portion 23 and the outflow path portion 25 in the flow frames 20 and 50 can be minimized . Therefore, when the flow frames 20 and 50 according to the first embodiment are used, a compact redox flow secondary battery 100 can be manufactured.

Also, the flow rate uniformity of the electrolyte and the pressure loss can be minimized by introducing a variable channel having different cross-sectional areas and lengths of the channels 36 and 46, thereby minimizing the generation of the shunt current.

Further, since the flow rate distribution of the electrolytic solution can be improved by improving the flow rate uniformity of the electrolytic solution, the stack stability of the unit cells 10 can be improved. As a result, the stack stability of the unit cells 10 can be improved, so that the number of unit cells 10 stacked in the redox flow secondary battery 200 can be increased and the series connection characteristic can be widened.

In addition, by increasing the number of stacked unit cells 10 and increasing the series connection characteristic, it is possible to realize a high voltage of the redox flow secondary battery 200.

Second Embodiment

5 is a plan view showing a flow frame of a unit cell according to a second embodiment of the present invention.

1, 2 and 5, the flow frames 120 and 150 applied to the unit cell 10 include a first flow frame 120 applied to the first electrode 13, a second flow frame 120 applied to the second electrode 15, And the second flow frame 150, which has the same structure.

The flow frames 120 and 150 include a frame body 21, an injection flow path portion 23, and an outflow flow path portion 25. The frame body 21 is formed with electrode insertion holes 27 and 57 through which the electrodes 13 and 15 are inserted. The injection flow path portion 23 is formed in the frame body 21 on one side of the electrode insertion holes 27 and 57 and injects the electrolyte into the electrode insertion holes 27 and 57. The outflow channel portion 25 is formed on the other frame body 21 facing the one side with the electrode insertion holes 27 and 57 as a center, and discharges the electrolyte solution from the electrode insertion holes 27 and 57.

Although the flow frames 120 and 150 according to the second embodiment have been described with the example in which the injection flow path portion 23 is formed on the upper portion of the electrode insertion holes 27 and 57 and the outflow channel portion 25 is formed on the lower portion, It is not limited thereto. For example, the flow frames 120 and 150 may have an injection flow channel portion 23 formed at a lower portion with respect to the electrode insertion holes 27 and 57, and an outflow channel portion 25 formed at an upper portion thereof.

One side of the electrode insertion holes 27 and 57 on which the injection flow path portion 23 is provided and the other side of the electrode insertion holes 27 and 57 on which the flow path portion 25 is provided are provided with electrode insertion holes 27 and 57 Microinjection flow paths 17 and microextraction flow paths 19 are formed so that the electrolytic solution can flow uniformly throughout. The inflow channel portion 23, the outflow channel portion 25, the microfluidic channel 17 and the microfluidic channel 19 are formed in a negative shape on one side of the frame body 21, respectively.

At this time, the frame body 21 forms a contour of the flow frames 120 and 150, and may be implemented in a shape close to a rectangular plate, for example. As the material of the frame body 21, a plastic resin such as polyethylene (PE), polypropylene (PP), polystyrene (PS), or vinyl chloride (PVC) may be used.

The injection flow path portion 23 includes a first manifold 31 and a plurality of first channels 36. The outflow channel portion 25 includes a second manifold 41 and a plurality of second channels 46. Here, the plurality of first channels 36 includes a first main channel 33, a first branch tank 35, and a plurality of first branch channels 37. The plurality of second channels 46 includes a second main channel 43, a second branch 45, and a plurality of second branch channels 47.

Since the injection path portion 23 and the outflow path portion 25 have the same configuration, the description will be made with reference to the injection path portion 23 as follows. The injection path portion 23 and the outflow path portion 25 are formed symmetrically up and down about the electrode insertion holes 27 and 57.

The first manifold 31 is formed to penetrate the frame body 21. The first main channel 33 is formed in the frame body 21 and has one end connected to the first manifold 31 and having an inner diameter smaller than that of the first manifold 31. The first branch trench 35 is formed in the frame body 21 and is connected to the other end of the first main channel 33 and has an inner space larger than the inner diameter of the first main channel 33. The plurality of first branch channels 37 are formed in the frame body 21 and have one end connected to the first branch tank 35 and the other end connected to one side of the electrode insertion holes 27 and 57, Has a smaller inner diameter than the channel (33).

The first manifold 31 is connected to the injection port of the cell frame. The second manifold 41 is connected to the outlet of the cell frame. The electrolytic solution in the electrolyte tank is supplied to the electrode insertion holes 27 and 57 through the first manifold 31 through the injection port of the cell frame by the driving of the pump, The electrolytic solution is recovered to the electrolyte tank through the outlet of the cell frame 81 through the second manifold 41. The first manifold 31 and the second manifold 41 may be formed on the opposite sides of the electrode insertion holes 27 and 57 facing each other.

The first manifold 31 may be formed at one side edge of the electrode insertion holes 27 and 57 when the electrode insertion holes 27 and 57 are in the form of a rectangular tube.

One side of the first main channel 33 may be connected to the first manifold 31 and may be formed horizontally on one side of the electrode insertion holes 27 and 57. In the first embodiment, an example in which the first main channel 33 is horizontally formed on one side of the upper portion of the electrode insertion holes 27 and 57 is disclosed.

The first branch trench 35 mediates the connection of the first main channel 33 and the plurality of first branch channels 37. The first branch trough 35 uniformizes the flow velocity distribution in the plurality of first branch channels 37 when the electrolyte flows from the first main channel 33 to the plurality of first branch channels 37. The first branch tank 35 may have a circular or elliptical cross section and an inner diameter of 1 to 10 times the inner diameter of the first main channel 33.

The plurality of first branch channels 37 are connected at one end to the first branch tank 35 and at the other end to different points on one side of the electrode insertion holes 27, That is, the other ends of the plurality of first branch channels 37 are connected to different points of the microinjection flow path 17 formed on one side of the electrode insertion holes 27, 57. One side of the electrode insertion holes 27 and 57 to which the plurality of first branch channels 37 are connected is the side of the electrode insertion holes 27 and 57 located on the side where the injection flow path portion 23 is formed.

The plurality of first branch channels 37 are formed in the first branch tank 35 so as to be capable of uniformly and uniformly injecting the electrolyte solution into the electrode insertion holes 27 and 57 through the micro- Sectional shape and length are increased as the distance to the point connected to the holes 27 and 57 increases. The reason for forming the plurality of first branch channels 37 in this way is that the pressure loss can be minimized by securing the same DELTA p.

Although the injection path portion 23 according to the second embodiment has an example in which one first main channel 33 and five first branch channels 37 are provided, the present invention is not limited thereto. The injection channel portion 23 may include at least one first main channel 33 and a larger number of first branch channels 37 than the first main channel 33. [

In order that the flow rate of the electrolytic solution flowing into the electrode insertion holes 27 and 57 through the injection flow path portion 23 can be supplied to one side of the electrode insertion holes 27 and 57 as a whole at the same speed, Sectional area of the first manifold 31 and the cross-sectional area of the first manifold 31 in a one-to-one relationship so that there is no pressure difference. In order to allow the flow rate of the electrolytic solution flowing out from the electrode insertion holes 27 and 57 to flow out to the other side of the electrode insertion holes 27 and 57 at the same speed as the whole, It is preferable that the cross-sectional area of the second manifold 41 is one-to-one so that there is no pressure difference.

As described above, the flow frames 120 and 150 according to the second embodiment can minimize the generation of shunt current by increasing the shunt resistance by configuring the flow path structure with the main channel and the plurality of branch channels.

In other words, in the second embodiment, by designing the flow path of the electrolytic solution of the flow frames 120 and 150 as a main channel having one large width and a branch channel having five small widths, it is possible to reduce the number of channels in the main channel, So that the shunt current due to the increase in shunt resistance due to the effect of reducing the cross-sectional area in the channel can be reduced.

In addition, the width and length of each branched branch channel are kept constant, and the flow rates in each branch channel are designed to be the same. A microfiltration flow path 17 and a microfiltration flow path 19 are provided on one side surface and the other side surface of the electrode in the direction in which the electrolyte flows so that a uniform flow distribution can be achieved.

By providing a circular or elliptical branching point at which the branch channels are branched from the main channel, the flow rate distribution in the branch channel is made uniform.

Third Embodiment

On the other hand, in the first and second embodiments of the present invention, an example in which the injection flow path portion 23 and the outflow flow path portion 25 are formed symmetrically about the electrode in the flow frames 20, 50, 120, It is not. For example, as shown in FIG. 6, the flow frames 220 and 250 according to the third embodiment are formed such that the injection path portion 23 and the outflow path portion 25 are linearly symmetrical with respect to the electrode, and they are formed in opposite directions.

6 is a plan view showing flow frames 220 and 250 of a unit cell according to a third embodiment of the present invention.

6, the flow frames 220 and 250 of the unit cell according to the third embodiment are different from the flow frames 120 and 150 according to the second embodiment in that the injection flow path portion 23 and the outflow flow path portion 25 And have the same structure as the flow frames 120 and 150 of the unit cell according to the second embodiment, except that they are formed in opposite directions to each other. The first and second manifolds 31 and 41 of the injection path portion 23 and the outflow path portion 25 are formed in the diagonal direction with respect to the electrode insertion holes 27 and 57.

It should be noted that the embodiments disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding, and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

10: Unit cell
11: Membrane
13: first electrode
15: second electrode
17:
19: Microflow channel
20: first flow frame
21: frame body
23:
25:
27: First electrode insertion hole
31: first manifold
33: First main channel
35: The first minute
36: First channel
37: First branch channel
41: second manifold
43: Second main channel
45: The second minute
46: Second channel
47: second branch channel
50: second flow frame
57: Second electrode insertion hole
61: first bipolar plate
69: second bipolar plate
71: 1st Total
79: The 2nd Total
81: first cell frame
89: Second cell frame
91: First electrolyte tank
92: first pump
93: first inlet pipe
94: First outflow pipe
96: Second electrolyte tank
97: Second pump
98: second inlet pipe
99: Second outflow pipe
100, 200: redox flow secondary battery

Claims (8)

A frame body having an electrode insertion hole in which an electrode is installed at a central portion thereof;
An injection channel formed in the frame body on one side of the electrode insertion hole to inject an electrolyte into the electrode insertion hole; And
And an outflow channel portion formed on the other side of the frame body facing the one side with respect to the electrode insertion hole and discharging the electrolyte solution from the electrode insertion hole,
And the inflow channel portion and the outflow channel portion are respectively connected to the inflow-
A manifold formed through the frame body; And
And a plurality of channels formed on the frame body and having one end connected to the manifold and the other end connected to one side of the electrode insertion hole and having different cross-sectional areas and lengths,
Wherein the plurality of channels have a shape in which a cross-sectional area and a length are increased as the distance from the manifold to a point connected to the electrode insertion hole increases, and the following relationship is satisfied: Flow Flow Frame for secondary flow battery.

(Where l ₁ and l ₂ are the lengths of arbitrary channels 1 and 2, and D ₁ and D ₂ are the diameters of arbitrary channels 1 and 2) delete The method according to claim 1,
The electrode insertion hole has a rectangular tube shape,
The manifold is formed on one side edge of the electrode insertion hole,
Wherein the plurality of channels include a horizontal horizontal channel part on one side of the electrode insertion hole and a vertical channel part connecting the horizontal channel part and one side of the electrode insertion hole in a vertical direction. Flow frame. 2. The apparatus of claim 1,
A main channel formed in the frame body and connected at one end to the manifold and having an inner diameter smaller than that of the manifold;
A branching tank formed on the frame body and connected to the other end of the main channel and having an inner space larger than an inner diameter of the main channel;
A plurality of branch channels formed in the frame body, one end connected to the branch bank and the other end connected to one side of the electrode insertion hole and having an inner diameter smaller than that of the main channel;
And a flow frame for a redox flow secondary battery. 5. The apparatus of claim 4, wherein the plurality of branch channels comprise:
Wherein a sectional area and a length of the flow frame increase as a distance from the branching tank to a point connected to the electrode insertion hole increases. 5. The method of claim 4,
Wherein the branch tank has a circular or elliptical cross section and an inner diameter of 10 times or less the inner diameter of the main channel. The method according to claim 1,
Wherein the injection path portion and the manifold portion of the outflow path portion are formed on one of the corners opposite to each other with respect to the electrode insertion hole and one of the corners on the diagonal side. A separator, a first electrode and a second electrode disposed opposite to each other with the separator interposed therebetween, first and second electrodes respectively connected to the first and second electrodes for flowing an electrolyte solution into the first and second electrodes, A plurality of unit cells stacked with a flow frame; And
A plurality of bipolar plates interposed between the plurality of unit cells and stacked on both sides of the plurality of stacked unit cells,
Wherein the first and second flow frames each comprise:
A frame body having an electrode insertion hole in which an electrode is installed at a central portion thereof;
An injection channel formed in the frame body on one side of the electrode insertion hole to inject an electrolyte into the electrode insertion hole; And
And an outflow channel portion formed on the other side of the frame body facing the one side with respect to the electrode insertion hole and discharging the electrolyte solution from the electrode insertion hole,
And the inflow channel portion and the outflow channel portion are respectively connected to the inflow-
A manifold formed through the frame body; And
And a plurality of channels formed on the frame body and having one end connected to the manifold and the other end connected to one side of the electrode insertion hole and having different cross-sectional areas and lengths,
Wherein the plurality of channels have a shape in which a cross-sectional area and a length are increased as the distance from the manifold to a point connected to the electrode insertion hole increases, and the following relationship is satisfied: Doss flow secondary battery.

(Where l ₁ and l ₂ are the lengths of arbitrary channels 1 and 2, and D ₁ and D ₂ are the diameters of arbitrary channels 1 and 2)

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