KR200463822Y1 - Bipolar plate for redox flow battery - Google Patents

Abstract

The present invention provides a bipolar plate for preventing a short circuit, preventing leakage of an electrolyte, maintaining durability, making it easy to manufacture, and a compact redox flow battery.
The bipolar plate includes a body 310 formed of a rectangular carbon plate; A plurality of longitudinal flow paths 321 formed at regular intervals along the longitudinal direction of the body 310 so that the anode electrolyte flows to one side of the body 310 to generate redox, and each of the bell Two transverse flow paths 322 for interconnecting both ends of the direction flow paths 321, an electrolyte supply line 323 formed for introducing a positive electrolyte into one of the transverse flow paths 322, and another An anode electrolyte flow path 320 including an electrolyte discharge line 324 for discharging the anode electrolyte passing through the longitudinal flow path 321 and the transverse flow path 322 in one transverse flow path 322; An anode electrolyte supply hole 330 connected to the electrolyte supply line 323 to supply the cathode electrolyte to the anode electrolyte flow path 320; A positive electrolyte discharge hole 340 connected to the electrolyte discharge line 324 to discharge the positive electrolyte passing through the positive electrolyte passage 320; A plurality of longitudinal flow paths 351 formed at regular intervals along the longitudinal direction of the body 310 so that the cathode electrolyte flows to the other side of the body 310 to generate redox, and each of the species Two transverse flow paths 352 for interconnecting both ends of the direction flow paths 351, an electrolyte supply line 353 formed to introduce a cathode electrolyte into one of the transverse flow paths 352, and It consists of an electrolyte discharge line 354 for discharging the negative electrolyte passing through the longitudinal flow path 351 and the transverse flow path 352 to one of the transverse flow path 352, the durability of the body 310 And a cathode electrolyte flow passage 350 formed so as not to be positioned on the same through shaft XX penetrating through the body 310 to maintain rigidity. A cathode electrolyte supply hole 360 connected to the electrolyte supply line 353 to supply a cathode electrolyte to the cathode electrolyte flow path 350; A negative electrolyte discharge hole 370 connected to the electrolyte discharge line 354 to discharge the negative electrolyte passing through the negative electrolyte flow path 350; And to prevent the electrical short circuit due to the direct contact between each of the electrolyte supply hole (330; 360) and the electrolyte discharge hole (350; 370) and the electrolyte, and to maintain the liquid tightness with the neighboring current collector plate and electrode plate, Coating parts formed by fluorine resin powder coating around both side surfaces of the body 310 except for the electrolyte supply holes 330 and 360, the electrolyte discharge holes 350 and 370, and the electrolyte flow paths 320 and 350. 380).

Description

Bipolar plate for redox flow battery {Bipolar plate for redox flow battery}

The present invention relates to a bipolar plate used in a redox flow battery, also called a secondary battery, and more specifically, a short circuit by coating a fluorine resin having a predetermined thickness around the electrolyte supply hole and the discharge hole of the bipolar plate and the bipolar plate. The present invention relates to a bipolar plate for a redox flow battery, which prevents and maintains liquid tightness with neighboring components, facilitates installation of a bipolar plate, and improves durability and achieves a compact battery stack structure.

Recently, renewable energy, such as solar energy and wind energy, has been spotlighted as a method for suppressing greenhouse gas emission, which is a major cause of global warming, and a lot of researches are being carried out for their practical use. However, such renewable energy is greatly affected by the location environment and natural conditions. Moreover, there is a disadvantage in that renewable energy cannot supply energy evenly continuously because the output fluctuates severely.

Therefore, to evenly output energy, it is important to develop a storage device that stores energy when the output is high and uses the stored energy when the output is low. Such representative mass storage devices include lead acid batteries, NaS batteries, and the like. Redox Flow Battery (RFB).

Although lead acid batteries are widely used commercially compared to other batteries, they have the disadvantages of low efficiency and maintenance costs due to periodic replacement and disposal of industrial wastes caused by battery replacement, and NaS batteries have high energy efficiency. It is an advantage, but has the disadvantage of operating at a high temperature of more than 300 ℃. On the other hand, since the redox flow battery is low in maintenance cost, can be operated at room temperature, and has a feature of independently designing capacity and output, a lot of research is being conducted into mass storage devices.

On the other hand, in the case of redox flow battery, the bipolar plate, the electrode plate, and the membrane are repeatedly stacked, so that the capacity can be increased, which is advantageous for the large size, easy to expand the capacity, operates at room temperature, and the initial cost is low, but there are many bipolar plates. In the stacked redox flow battery, the electrolyte passes through the flow path of the bipolar plate and finally flows through the flow path of the bipolar plate having different poles.At this time, a short circuit (electrical short) occurs during the passage of the redox redox. There was a problem that causes a decrease in the efficiency of the flow battery.

One example for solving the problem of short circuit in such a redox flow battery is disclosed in Korean Patent Publication No. 10-2011-116624. According to the redox flow battery structure of Patent Publication No. 10-2011-116624, a plurality of bipolar plates in which a plurality of battery cells composed of a bipolar plate, an electrode plate divided into a positive electrode plate and a negative electrode plate, and a membrane are stacked in series The plate has a redox flow battery structure that sequentially cross-feeds the catholyte and the anolyte electrolyte, and the bipolar plate has an electrolyte inlet and an electrolyte outlet formed at a lower portion and an upper portion thereof. Is formed, and the left and right portions of the electrolyte inlet and the electrolyte outlet that are symmetrically in the vertical line are formed so that flow passage holes through which the electrolyte having different poles pass are formed, and the electrolyte passage through which an insulating short prevention tube is inserted into the flow passage holes. Has a configuration to block the contact between the bipolar plate and It is.

With this configuration, the bipolar plate and the positive electrode plate membrane negative electrode plate is composed of one cell, and in a structure in which a plurality of cells are stacked in series, the electrolyte injected to one side of the bipolar plate has different poles as it passes through each cell sequentially. Teflon short-circuit tube is installed in the flow passage to prevent electrolytes having different poles from contacting the bipolar plate, thereby preventing battery efficiency from being reduced due to a short circuit caused by contact, and also a short built in the flow passage. By separating two or more protective tubes and overlapping some of the separated objects to provide a buffer against consolidation, the both ends of the short resistant tubes are in close contact with the positive electrode plate and the negative electrode plate stacked on both sides of the bipolar plate, thereby providing a gap with the electrode plate. To prevent electrolyte from entering the bipolar plate And it provides an effect that can be.

However, the Patent Publication No. 10-2011-116624 has been shown to cause some problems despite the above technical features and effects. First, since the bipolar plate and the short prevention tube are manufactured and formed separately, the short prevention tube must be integrated in a manner of inserting or inserting into the passage hole of the bipolar plate, thereby making the manufacturing complicated and increasing the manufacturing cost.

In addition, a gap may be generated between the passage hole and the short prevention tube, which may result in leakage of the electrolyte, and due to the protrusion of the short prevention tube, liquid contact between the bipolar plate and the neighboring electrode plate may not be achieved. There is a problem that leakage occurs.

In addition, since each flow path formed on both sides of the bipolar plate is located on the same cross-section, the thickness of the bipolar plate should be thick, difficult to process the flow path, and due to the absolute thickness of the bipolar plate, the overall cell stack and There is a problem that the battery structure becomes larger in size or requires excessive installation space compared to the output power.

The present invention is to solve the above problems, the object of the present invention is to prevent the short circuit by coating the insulating material without installing a separate short prevention means in the through-hole of the bipolar plate, the insulating material around the bipolar plate Coating to maintain the liquid tightness between neighboring electrode plates to prevent leakage of the electrolyte, and to avoid the thickness and completion of the bipolar plate itself by avoiding each of the electrolyte flow paths formed on both sides of the bipolar plate on the same cross-section It is to provide a bipolar plate for a redox flow battery that can minimize the size of the battery.

The present invention has been made in order to achieve the above object, the body formed of a carbon plate in a bipolar plate for redox flow battery, which is installed with a protective plate, a current collecting plate, an electrode plate, and a membrane to generate electricity by a polar electrolyte solution. ; A plurality of longitudinal flow paths formed at regular intervals along the longitudinal direction of the body and the both ends of each of the longitudinal flow paths so as to generate redox while the positive electrolyte flows to one side of the body. Two transverse flow paths, an electrolyte supply line formed to introduce a positive electrolyte into one of the transverse flow paths, and a positive electrolyte passing through the longitudinal flow path and the transverse flow path to the other transverse flow path; An anode electrolyte flow passage formed of an electrolyte discharge line for discharging; An anode electrolyte supply hole connected to the electrolyte supply line to supply the cathode electrolyte to the anode electrolyte flow path; An anode electrolyte discharge hole connected to the electrolyte discharge line to discharge the anode electrolyte passing through the cathode electrolyte flow path; A plurality of longitudinal flow paths formed at regular intervals along the longitudinal direction of the body and the both ends of each of the longitudinal flow paths so that the cathode electrolyte flows to the other side of the body to generate redox Two transverse flow passages, an electrolyte supply line formed to introduce a negative electrolyte into one of the transverse flow passages, and a negative electrolyte passing through the longitudinal flow passage and the transverse flow passage in the other transverse flow passage; A cathode electrolyte flow path formed of an electrolyte discharge line for discharging, the cathode electrolyte flow path formed so as not to be positioned on the same through shaft passing through the body to maintain durability and rigidity of the body; A cathode electrolyte supply hole connected to the electrolyte supply line to supply a cathode electrolyte to the cathode electrolyte flow path; A cathode electrolyte discharge hole connected to the electrolyte discharge line to discharge the cathode electrolyte passing through the cathode electrolyte flow path; And the electrolyte supply hole and the electrolyte discharge hole and the electrolyte supply hole so as to prevent an electrical short circuit due to direct contact between each of the electrolyte supply hole and the electrolyte discharge hole and the electrolyte solution, and to maintain a liquid tightness with the neighboring current collecting plate and the electrode plate. A coating part formed by fluororesin powder coating is formed around both sides of the body except for an electrolyte flow path region. The bipolar plate includes a carbon plate in which dry carbon is cut by a dry cutting method to form a carbon plate. Milling and edge machining the carbon plate to form a body; Forming a positive electrolyte flow path having a predetermined shape on one side of the body, and forming a negative electrolyte flow path on the other side so as not to exist on the same through shaft as the positive electrolyte flow path; Forming respective electrolyte supply holes and electrolyte discharge holes communicating with an electrolyte supply line and an electrolyte discharge line of each of the electrolyte flow paths; Forming a coating part by coating a peripheral portion of the body except the electrolyte flow path, the electrolyte supply hole, and the electrolyte discharge hole with fluorine resin; The body, the electrolyte flow path, the electrolyte supply hole and the electrolyte discharge hole is formed by inspecting cracks, residues, scratches, pinholes, etc .: The coating unit, by examining the entire body to determine whether the coating, the coating is If it is determined possible, masking a central portion of the body including the electrolyte flow path using a masking tape; Inspecting the periphery of the body including each of the electrolyte supply hole and the electrolyte discharge hole and degreasing using isopropyl alcohol or distilled water; Spraying a liquid teflon primer on the periphery of the body including the electrolyte supply hole and the electrolyte discharge hole, heat-processing for 10 to 15 minutes at a temperature of 140 to 160 ° C., and plastic coating it; Spraying a liquid ETFE resin on the lower coating surface to prevent heat shrinkage, heat treatment at a temperature of 300 to 400 ° C. for 10 to 60 minutes, lowering the temperature to 150 ° C., and then naturally cooling the film to heavy coating; Powder coating of the ETFE powder to prevent moisture infiltration, heat treatment at a temperature of 400 ° C. for 10 to 60 minutes, lowering the temperature to 150 ° C., and then naturally cooling the phase coating; Repeating the heavy coating and the phase coating until the fluororesin coating thickness is reached to complete the fluororesin powder coating; Inspecting the appearance of the coating, the thickness of the coating film, the occurrence of cracks, the residue oil, the scratch oil, the pin oil and the like; It is formed by removing the masking tape: The thickness of the coating portion is 135 ~ 165㎛: ETFE resin forming the coating portion has a tensile strength of 4.1 ~ 4.7 kg / mm2, flexural strength of 3.5 ~ 4.0 kg / mm2, 130 ~ It has a flexural modulus of 150 kg / mm 2, a compressive strength of 3.5 to 4.0 kg / mm 2, a linear expansion coefficient of 8.5 to 9.3, and a heat resistance of -50 to 200 ° C.

According to the bipolar plate for redox flow battery according to the present invention, the fluorine resin is integrally coated without installing separate insulating means in the electrolyte supply hole and the electrolyte discharge hole of the bipolar plate to prevent short-circuit as well as easy to manufacture In addition, the fluorine resin is coated around the bipolar plate including the electrolyte supply hole and the discharge hole to maintain the liquid tightness between neighboring current collector plates and the electrode plate to prevent leakage of the electrolyte solution, and the electrolyte flow paths formed on both sides of the bipolar plate Positioned on different cross sections, the durability of the bipolar plate is improved, and there is a remarkable effect of reducing the thickness of the entire battery.

1 is an exploded perspective view schematically showing a structure of a redox flow battery to which a bipolar plate according to the present invention is applied.
2 is a perspective view of a bipolar plate according to the present invention.
3 is a front view showing a positive electrolyte passage of the bipolar plate of FIG.
4 is a rear view illustrating a cathode electrolyte flow path of the bipolar plate of FIG. 2.
5 is an enlarged cross-sectional view taken along the line VV of FIG. 2.
6 is an enlarged cross-sectional view taken along the line VI-VI of FIG. 2.

Hereinafter, a preferred embodiment of a bipolar plate for a redox flow battery according to the present invention will be described in detail with reference to the accompanying drawings.

First, referring to the basic structure of a redox flow battery to which a bipolar plate according to the present invention is applied as shown in FIG. 1, two protections are formed on both sides to form an appearance of the battery and protect components disposed therebetween. The plate, that is, the first protective plate 11 and the second protective plate 12 is installed, the first current collector plate 21 is installed in contact with the inside of the first protective plate 11, the second protective plate 12 The second current collecting plate 22 is installed in contact with the inside of the.

The first bipolar plate 31 and the first electrode plate are disposed between the first current collector plate 21 and the second current collector plate 22 from the first current collector plate 21 toward the second current collector plate 22. 41, the first membrane 51, the second electrode plate 42, the second bipolar plate 32, the third electrode plate 43, the second membrane 52, the fourth electrode plate 44, The third bipolar plate 33, the fifth electrode plate 45, the third membrane 53, the sixth electrode plate 46, and the fourth bipolar plate 34 maintain a mutual contact state and have a stack structure. . Of course, such a structure is basic, and the number of each component may be appropriately selected according to the required capacity or specification, and each of the electrode plates 41 to 46 may be supplied with a polar electrolyte and each of the bipolar plates. Depending on the arrangement of the 31 to 34 may have a polarity of the positive electrode or the negative electrode.

According to such a configuration, for example, the positive electrode electrolyte and the negative electrode electrolyte supplied through the respective through holes formed in the lower portion of the first protective plate 11 pass through the through holes of the first current collecting plate 21, and thus the first bipolar plate 31, First electrode plate 41, first membrane 51, second electrode plate 42, second bipolar plate 32, third electrode plate 43, second membrane 52, fourth electrode plate The second current collecting plate 22 is passed through the third bipolar plate 33, the fifth electrode plate 45, the third membrane 53, the sixth electrode plate 46, and the fourth bipolar plate 34. The positive electrode is generated by a redox reaction between the positive electrode electrolyte and the positive electrode electrolyte channel of each of the bipolar plates 31 to 34 while being discharged through the second protective plate 11 through the through hole of the positive electrode. A negative electric charge is generated by a redox reaction between an electrolyte solution and a cathode electrolyte flow path of each of the bipolar plates 31 to 34. It would be to generate a predetermined electrical.

Here, the positive electrolyte flows only through the positive electrolyte flow path formed on one side of each of the bipolar plates 31 to 34, and conversely, the negative electrolyte flows through the negative electrolyte flow path formed on the other side of the bipolar plates 31 to 34. Pass through the bay.

In particular, each of the bipolar plates 31 to 34 (hereinafter referred to as the bipolar plate 300) applied to the redox flow battery configured as described above has the following characteristics.

As shown in FIGS. 2 to 6, the bipolar plate 300 includes a rectangular body 310. The body 310 is preferably formed of a carbon plate or graphite plate having a predetermined thickness.

A cathode electrolyte flow path 320 is formed on one side of the body 310 to generate a redox while the anode electrolyte flows. The anode electrolyte flow path 320 includes a plurality of longitudinal flow paths 321 formed at regular intervals along the length direction of the body 310, and two for interconnecting both ends of each of the longitudinal flow paths 321. It consists of a transverse flow path 322.

An electrolyte supply line 323 for introducing a positive electrolyte is formed in one of the transverse flow paths 322, and the longitudinal flow path 321 and the transverse direction are formed in the other transverse flow path 322. An electrolyte discharge line 324 is formed to discharge the positive electrolyte that has passed through the directional flow passage 322.

In addition, an anode electrolyte supply hole 330 for supplying an anode electrolyte to the cathode electrolyte flow path 320 is formed in an upper portion or a lower portion of the body 310. Of course, the anode electrolyte supply hole 330 is connected to the electrolyte supply line 323, so that the anode electrolyte supplied through the anode electrolyte supply hole 330 is the longitudinal direction through the electrolyte supply line 323 It is supplied to the flow path 321 and the transverse flow path 322 to flow.

In addition, a cathode electrolyte discharge hole 340 for drilling or supplying the anode electrolyte passing through the anode electrolyte flow path 320 to another subsequent bipolar plate is drilled in the lower portion or the upper portion of the body 310. The positive electrolyte discharge hole 340 is connected to the electrolyte discharge line 324 to discharge the positive electrolyte passing through the electrolyte discharge line 324 via the longitudinal flow passage 321 and the transverse flow passage 322. It is to let.

On the other hand, the cathode electrolyte flow path 350 is formed on the other side of the body 310 to generate redox while the cathode electrolyte flows. The cathode electrolyte flow path 350 includes a plurality of longitudinal flow paths 351 formed at regular intervals along the length direction of the body 310, and two for interconnecting both ends of each of the longitudinal flow paths 351. It consists of a transverse flow path 352.

In each of the transverse flow paths 352, an electrolyte supply line 353 for introducing a cathode electrolyte is formed, and in the other transverse flow path 352, the longitudinal flow path 351 and the transverse direction. An electrolyte discharge line 354 is formed to discharge the positive electrolyte passing through the directional flow passage 352.

In addition, a cathode electrolyte supply hole 360 for supplying the cathode electrolyte to the cathode electrolyte flow path 350 is drilled in the lower or upper portion of the body 310. Of course, the anode electrolyte supply hole 360 is connected to the electrolyte supply line 353, so that the cathode electrolyte supplied through the cathode electrolyte supply hole 360 is in the longitudinal direction through the electrolyte supply line 353. It is supplied to the flow path 351 and the transverse flow path 352 to flow.

In addition, a cathode electrolyte discharge hole 370 for supplying or recovering the cathode electrolyte passing through the cathode electrolyte flow path 350 to another subsequent bipolar plate is drilled on the upper or lower portion of the body 310. The cathode electrolyte discharge hole 370 is connected to the electrolyte discharge line 354 to discharge the cathode electrolyte passing through the electrolyte discharge line 354 via the longitudinal flow path 351 and the transverse flow path 352. It is to let.

In particular, according to one feature of the present invention, the anode electrolyte flow path 320 formed on one side of the body 310 and the cathode electrolyte flow path 350 formed on the other side are the same through shaft (XX) of the body 310; It is preferable that it is formed so as not to exist in the phase. Due to this structure, it is possible to increase the durability of the body 310, to minimize the thickness, as well as to keep the entire bipolar plate 300 compact.

On the other hand, the bipolar plate 300 includes a coating portion 380 for preventing the short circuit caused by the electrolyte, as well as for the stable liquid-tight with the neighboring components.

The coating part 380 is coated with a predetermined thickness on each of the electrolyte supply holes 330 and 360 and the electrolyte discharge holes 340 and 370 to prevent electrical short circuits by the electrolyte, and also the bipolar plate 300. Each electrolyte formed in the periphery of the body 310, that is, the body 310 for liquid-tight or airtight contact between the adjacent electrode plates 41 to 46 and the current collector plates 21 and 22; It is preferable that the peripheral portion of the body 310 is formed to have a predetermined thickness except for the flow paths 320 and 350.

Here, the thickness of the coating part 380 is 135 ~ 165㎛, if less than 135㎛ may cause coating defects due to the generation of a pin hole (pine hole), if more than 165㎛ electrolyte fluidity and neighboring electrodes The assemblability and airtightness between the plate and the current collecting plate may be degraded. Therefore, the most appropriate coating 380 has a thickness of about 150 μm.

In addition, the coating part 380 is excellent in insulation, chemical resistance, heat resistance, oil resistance, non-tackiness and electrical properties, and is formed of a fluororesin coating having a low coefficient of friction. As a material of such a fluororesin, a fluororesin mainly composed of ETFE (ethylene-tetrafluoroethylene), PTFE, PFA, FEP, ECTFE, PVDF and the like is used.

According to a preferred embodiment of the present invention, the tensile strength of 4.1 ~ 4.7 kg / mm 2, the flexural strength of 3.5 ~ 4.0 kg / mm 2, the flexural elasticity of 130 ~ 150 kg / mm 2, the compressive strength of 3.5 ~ 4.0 kg / mm 2, 8.5 The coating part 380 was formed by coating a fluorine resin containing ETFE having a linear expansion coefficient of ˜9.3 and a heat resistance of −50 to 200 ° C. as a powder coating method.

Referring to the manufacturing method of the bipolar plate 300 according to the present invention configured as described above in more detail as follows.

First, the body 310 is prepared from a carbon plate of a shape suitable for the final redox flow battery to be completed. In more detail, the bulk carbon body is slit freely by a dry cutting method, and the squeezed carbon plate is milled and edge processed to form a body 310 having a predetermined size.

A cathode electrolyte flow path 320 having a predetermined shape is formed on one side of the body 310 prepared as described above, and a cathode electrolyte flow path 350 is formed on the other side. Here, the formation of each of the electrolyte flow paths 320 and 350 may not exist on the same through shaft XX passing through the cross section of the body 310 to maintain durability and rigidity of the body 310. It must be formed.

In addition, each of the electrolyte supply holes 330 and 360 and the electrolyte discharge holes 340 and 370 communicating with the electrolyte supply lines 323 and 353 and the electrolyte discharge lines 324 and 354 of the respective electrolyte flow paths 320 and 350, respectively. ).

Thereafter, as described above, the body 310 having the electrolyte flow path 320 and 350, the electrolyte supply holes 330 and 360, and the electrolyte discharge holes 340 and 370 is coated as follows.

First, the entire body 310 is inspected to determine whether the coating is possible, and when it is determined that the coating is possible, the body 310 of the body 310 including a fire coating area, that is, the electrolyte flow path 320; Mask the center part using a masking tape. Here, the masking tape is a masking tape formed of a PTFE resin having chemical resistance, high heat resistance, electrical properties, low friction coefficient, and self-lubrication for stability in a coating process to be described later.

Next, after inspecting the periphery of the body 310 including the coating area, that is, each of the electrolyte supply holes 330 and 360 and the electrolyte discharge holes 340 and 370, isopropyl alcohol (IPA) or distilled water is inspected. Degreasing treatment using

Thereafter, the coating area is sprayed by spraying a liquid primer (primer) containing Teflon as a main component. Such primer undercoat is to increase the adhesion of the powder coating to be described later, and the plastic processing by heat treatment for 10 to 15 minutes at a temperature of 140 ~ 160 ℃ after spraying the primer. Here, when the heat treatment time is 10 minutes or less, a coating defect may occur, and when the heat treatment time exceeds 15 minutes, since the adhesion to the powder coating thereafter is lowered, a heat treatment time of about 13 minutes is preferable.

When the plastic working is completed, after cooling in air, the coating part is inspected for the presence of residues and other abnormalities, and when an abnormality occurs, the residues are removed and the surface is treated cleanly.

Next, in order to prevent thermal contraction of the coating unit 380, the liquid ETFE resin is sprayed on the lower coating surface and subjected to heavy coating. After such a heavy coating, the heat treatment for 10 to 60 minutes at a temperature of about 300 ~ 400 ℃, lowered to a temperature of about 150 ℃ and then naturally cooled to complete the firing treatment. This heavy coating process can be repeatedly performed until a predetermined thickness is obtained.

Thereafter, in order to prevent moisture infiltration of the coating unit 380, phase coating is performed by powder coating ETFE powder. After such phase coating, heat treatment is performed at a temperature of about 400 ° C. for 10 to 60 minutes, the temperature is lowered to about 150 ° C., and then cooled naturally to complete the firing treatment. Of course, such powder coating for phase coating can be repeatedly performed until a predetermined thickness is obtained.

According to a preferred embodiment of the present invention, when the overall thickness of the coating portion 380 is set to 135 ~ 165㎛, repeat the one thickness of the heavy coating and the lower coating 3 times each 22.5 ~ 27.5㎛ or the same thickness The heavy coating and the low coating can be repeated three times in order to complete the fluororesin powder coating.

When the fluororesin coating is completed as described above, the appearance of the coating, the thickness of the coating film, the presence of cracks, the residue residue, the scratching portion, the pinhole portion, etc. are examined to determine whether the pass is successful. The approved coating part has a coating thickness of 150 μm (tolerance ± 10%) in the present invention, and there should be no cracks, residues, scratches or pinholes.

Thereafter, the masking tape is removed, and the final and totally inspection is completed to complete the bipolar plate 300.

When the bipolar plate 300 is completed as described above, the first bipolar plate 31, the first electrode plate 41, and the first membrane (from the first current collecting plate 21 toward the second current collecting plate 22). 51, the second electrode plate 42, the second bipolar plate 32, the third electrode plate 43, the second membrane 52, the fourth electrode plate 44, the third bipolar plate 33, The fifth electrode plate 45, the third membrane 53, the sixth electrode plate 46, and the fourth bipolar plate 34 are disposed to manufacture a redox flow battery.

Here, each of the bipolar plates (31 to 34; 300) is disposed without the need to actually change or change the direction, the anode electrolyte flow path 320 provided on one side is supplied with only the anode electrolyte flows, the other side Since only the cathode electrolyte is supplied and flows through the provided cathode electrolyte flow path 340, electricity is generated by redox through contact between each electrolyte and the bipolar plate.

Meanwhile, in the present embodiment, the positive electrolyte and the negative electrolyte are described in a manner of sending and supplying in the forward direction, that is, in the same direction, but a person skilled in the art can achieve the same result by sending and supplying the respective electrolytes in the reverse direction. I will obviously understand that I can.

In particular, according to the bipolar plate 300 according to the present invention, the insulating performance of each of the electrolyte supply holes (330; 360) and each of the electrolyte discharge holes (340; 370) of the bipolar plates (31 ~ 34; 300) Since the coating part 380 is formed by the fluorine resin coating having the electric shock, that is, the short circuit does not occur due to different polarities, the efficiency of the battery is prevented.

In addition, by using an integrated fluorine resin coating method without manufacturing or inserting or installing separate insulation means in each of the electrolyte supply holes 330 and 360 and each of the electrolyte discharge holes 340 and 370, assembly and manufacture Will be quick and easy.

In addition, since the coating part 38 is formed on the periphery of the body 310 except for the electrolyte flow paths 320 and 340, the electrode plate adjacent to each of the bipolar plates 31 to 34; The liquid tightness or airtightness between the 41 to 46 and the current collector plates 21 and 22 may be maintained to prevent leakage of the electrolyte solution.

In addition, since the electrolyte flow paths 320 and 350 of each of the bipolar plates 31 to 34 and 300 are not formed on the same through shaft XX penetrating the body 310, the durability of the bipolar plates is improved. As well as the thickness can be reduced, the overall durability and compactness of the finished redox flow battery can be improved.

11, 12: protection plate 21, 22: current collector plate
31 to 34, 300: bipolar plate 41 to 46: electrode plate
51 to 53: membrane 310: body
320: anode electrolyte flow path 330: anode electrolyte supply hole
340: anode electrolyte discharge hole 350: cathode electrolyte flow path
360: cathode electrolyte supply hole 370: cathode electrolyte discharge hole
380: coating part

Claims (1)

In the bipolar plate for a redox flow battery, which is installed together with a protective plate, a current collecting plate, an electrode plate, and a membrane to generate electricity by a polar electrolyte,
A body 310 formed of a carbon plate;
A plurality of longitudinal flow paths 321 formed at regular intervals along the longitudinal direction of the body 310 so that the anode electrolyte flows to one side of the body 310 to generate redox, and each of the bell Two transverse flow paths 322 for interconnecting both ends of the direction flow paths 321, an electrolyte supply line 323 formed for introducing a positive electrolyte into one of the transverse flow paths 322, and another An anode electrolyte flow path 320 including an electrolyte discharge line 324 for discharging the anode electrolyte passing through the longitudinal flow path 321 and the transverse flow path 322 in one transverse flow path 322;
An anode electrolyte supply hole 330 connected to the electrolyte supply line 323 to supply the cathode electrolyte to the anode electrolyte flow path 320;
A positive electrolyte discharge hole 340 connected to the electrolyte discharge line 324 to discharge the positive electrolyte passing through the positive electrolyte passage 320;
A plurality of longitudinal flow paths 351 formed at regular intervals along the longitudinal direction of the body 310 so that the cathode electrolyte flows to the other side of the body 310 to generate redox, and each of the species Two transverse flow paths 352 for interconnecting both ends of the direction flow paths 351, an electrolyte supply line 353 formed to introduce a cathode electrolyte into one of the transverse flow paths 352, and It consists of an electrolyte discharge line 354 for discharging the negative electrolyte passing through the longitudinal flow path 351 and the transverse flow path 352 to one of the transverse flow path 352, the durability of the body 310 And a cathode electrolyte flow passage 350 formed so as not to be positioned on the same through shaft XX penetrating through the body 310 to maintain rigidity.
A cathode electrolyte supply hole 360 connected to the electrolyte supply line 353 to supply a cathode electrolyte to the cathode electrolyte flow path 350;
A negative electrolyte discharge hole 370 connected to the electrolyte discharge line 354 to discharge the negative electrolyte passing through the negative electrolyte flow path 350; And
To prevent the electrical short circuit due to the direct contact between each of the electrolyte supply holes (330; 360) and the electrolyte discharge holes (350; 370) and the electrolyte, and to maintain the liquid tightness with the neighboring current collector plate and the electrode plate, Coating portion 380 formed by fluorine resin powder coating around both side surfaces of the body 310 except for the electrolyte supply holes 330 and 360, the electrolyte discharge holes 350 and 370, and the electrolyte flow paths 320 and 350. ):
The bipolar plate 300,
A carbon plate of a bulk form is slack cut by a dry cutting method to form a carbon plate, and the carbon plate that has been cut is milled and edge-processed to form a body 310;
A cathode electrolyte flow path 320 having a predetermined shape is formed on one side of the body 310, and a cathode electrolyte flow path 350 is formed on the other side of the cathode electrolyte flow path 320 so as not to exist on the same through shaft XX as the anode electrolyte flow path 320. To form;
Respective electrolyte supply holes 330 and 360 and electrolyte discharge holes 340 and 370 communicating with the electrolyte supply lines 323 and 353 and the electrolyte discharge lines 324 and 354 of the respective electrolyte flow paths 320 and 350, respectively. To form;
The periphery of the body 310 except for the electrolyte flow paths 320 and 350, the electrolyte supply holes 330 and 360, and the electrolyte discharge holes 340 and 370 are coated with fluorine resin to coat the coating part 380. Forms;
It is formed by inspecting cracks, residues, scratches, pinholes, etc. of the body 310, the electrolyte flow paths 320 and 350, the electrolyte supply holes 330 and 360, and the electrolyte discharge holes 340 and 370:
The coating part 380,
After the entire body 310 is inspected to determine whether the coating is possible, if it is determined that the coating is possible, a masking tape is used to form a central portion of the body 310 including the electrolyte flow paths 320 and 350. Masking;
Inspecting a peripheral portion of the body 310 including each of the electrolyte supply holes 330 and 360 and the electrolyte discharge holes 340 and 370 and then degreasing using isopropyl alcohol (IPA) or distilled water;
Spraying a liquid teflon primer to the periphery of the body 310 including the electrolyte supply holes (330; 360) and the electrolyte discharge holes (340; 370), and at a temperature of 140 ~ 160 ℃ 10 ~ Heat-treat for 15 minutes, plastic processing and lower coating;
Spraying a liquid ETFE resin on the lower coating surface to prevent heat shrinkage, heat treatment at a temperature of 300 to 400 ° C. for 10 to 60 minutes, lowering the temperature to 150 ° C., and then naturally cooling the film to heavy coating;
Powder coating of the ETFE powder to prevent moisture infiltration, heat treatment at a temperature of 400 ° C. for 10 to 60 minutes, lowering the temperature to 150 ° C., and then naturally cooling the phase coating;
Repeating the heavy coating and the phase coating until the fluororesin coating thickness is reached to complete the fluororesin powder coating;
Inspecting the appearance of the coating, the thickness of the coating film, the occurrence of cracks, the residue oil, the scratch oil, the pin oil and the like;
It is formed by removing the masking tape:
The thickness of the coating portion 380 is 135 ~ 165㎛:
The ETFE resin forming the coating part 380 has a tensile strength of 4.1 to 4.7 kg / mm 2, a flexural strength of 3.5 to 4.0 kg / mm 2, a flexural elasticity of 130 to 150 kg / mm 2, and a compression of 3.5 to 4.0 kg / mm 2. A bipolar plate for a redox flow battery, characterized in that it has strength, a coefficient of linear expansion of 8.5 to 9.3, and heat resistance of -50 to 200 ° C.

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