TWI575805B - Bipolar Plate of Flow Cell and Producing Method Thereof - Google Patents

Description

Bipolar plate of liquid flow battery and manufacturing method thereof

The invention relates to a bipolar plate of a liquid flow battery and a manufacturing method thereof, in particular to an all-vanadium battery energy storage system, in particular to an injection molding method for forming an insulating acid-proof material around a graphite plate to become an integrated double Plate.

The all-vanadium battery uses a vanadium ion of different valence states in the electrolyte to carry out a redox reaction as a storage or release of electrical energy. The electrode itself does not participate in the reaction, and the electrolytes of the positive and negative electrodes are separated and stored in the external reservoir, so the self-discharge rate is low and the cycle life is long. Its characteristics are that the power of the battery and the energy that can be stored can be designed separately. The design of the battery structure needs to consider the distribution of the electrolyte in the reaction zone and reduce the divergence current. The all-vanadium battery is composed of a plurality of single cells connected in series, and since the electrolyte is electrically conductive, the electrolyte flowing between any two single cells generates a current (called a shunt current) due to a potential difference, and the current is not The internal load required is an internal load. Most of the way to reduce this divergence current is to increase the flow length of the main channel to the reaction zone electrolyte to increase the impedance of this part of the electrolyte. This flow path is designed on the outer frame of the insulating material, thus increasing the complexity of the all-vanadium battery structure. The conventional structure of the all-vanadium battery is as shown in Fig. 6, wherein the bipolar plate 3 is formed by sandwiching a graphite plate 32 with two insulating frames 31, wherein the function of the graphite plate 32 separates the positive and negative electrolytes and conducts electrons. The branch flow path 311 is located on the insulating frame 31. At the time of assembly, a gas-tight gasket 33 is required for the contact faces of each layer to prevent electrolyte leakage. However, the battery structure requires a large number of components, and the assembly takes time, resulting in an increase in battery cost. In view of the fact that the bipolar plate of the conventional flow battery sandwiches the graphite plate in the insulating frame, the bipolar plate of this design contains many parts, and the assembly process takes a long time. Therefore, the user-like users cannot meet the needs of the user in actual use.

The main object of the present invention is to overcome the above problems encountered in the prior art and to provide a bipolar plate for forming a flow battery of an integrated bipolar plate by molding an insulating acid-resistant material around a graphite plate by injection molding. Production Method. A secondary object of the present invention is to provide a composite flow cell design around a graphite plate, and also a flow battery that is formed on the frame by a branching flow path designed to reduce the bifurcation current by injection molding. Bipolar plate and its making method. Another object of the present invention is to provide a risk of increasing the bonding strength between an insulating acid-resistant material and a graphite plate and reducing the leakage of the electrolyte, thereby achieving a substantial reduction in the number of parts and a time-consuming assembly process, and reducing the cost of processing and assembly. Bipolar plate of liquid flow battery and manufacturing method thereof. For the purpose of the above, the present invention is a method for fabricating a bipolar plate of a flow battery, comprising at least the following steps: (A) providing a conductive graphite plate comprising an upper surface and a lower surface thereon, a plurality of first leakage preventing grooves are formed on the periphery of the lower surface; (B) an injection molding jig is provided to sandwich the inner edge of the graphite plate for positioning; (C) the insulating and acid resistant material is injection molded into the graphite by the injection molding jig Forming a frame around the plate, and forming a plurality of branch flow paths on the frame to form an integrated bipolar plate; and (D) mounting a plurality of cover plates on the frame and covering the plurality of branch flows A second leakage preventing groove is formed on the contact surface of each of the cover plates and the frame. In the above embodiment of the present invention, the injection molding jig includes an upper mold and a lower mold corresponding to the upper mold, and the cavity of the upper mold and the cavity of the lower mold cooperate with the integrated double The shape of the half of the plate is symmetrical. In the above embodiment of the present invention, the corresponding surfaces of the upper and lower molds are respectively provided with upper and lower mold holes corresponding to the shape of the integrated bipolar plate, and the upper and lower molds are arranged. Correspondingly clamping the graphite plate in the integrated bipolar plate, positioning the upper positioning block on the first leakage preventing groove edge surrounding the inner circumference of the surface of the graphite plate and being clamped by the lower die, and positioning the lower positioning block The inner peripheral edge of the lower surface of the graphite plate surrounds the first leakage preventing groove and is sandwiched by the upper mold, and the upper and lower molds cover the graphite plate and fix the position thereof. In the above embodiment of the invention, the insulating acid-resistant material is an epoxy resin, a polyimide or an acrylic. In the above embodiment of the present invention, the second leakage preventing groove is formed in a slightly meandering shape on the inner surface edge of each of the cover plates. The invention further relates to a bipolar plate of a flow battery, comprising: an integrated bipolar plate comprising a graphite plate having a plurality of first leakage preventing grooves around, and a graphite plate disposed by injection molding. a plurality of frames on the first leakage preventing groove, and the frame is provided with a plurality of branch flow channels; and a plurality of cover plates are disposed on the frame and covering the plurality of branch flow channels, and each A second leakage preventing groove is disposed on the contact surface of the cover plate and the frame. In the above embodiment of the invention, the plurality of branch channels are formed by injection molding. In the above embodiment of the present invention, the integrated bipolar plate is formed by an injection molding jig combined with an upper mold and a lower mold, and an insulating acid-proof material is injection molded around the graphite plate to form an injection molder of the frame. The cavity of the die is matched with the cavity of the lower die to match the shape of the half of the integrated bipolar plate. In the above embodiment of the present invention, the corresponding surfaces of the upper and lower molds are respectively provided with upper and lower mold holes corresponding to the shape of the integrated bipolar plate, and the upper and lower molds are arranged. Correspondingly clamping the graphite plate in the integrated bipolar plate, positioning the upper positioning block on the first leakage preventing groove edge surrounding the inner circumference of the surface of the graphite plate and being clamped by the lower die, and positioning the lower positioning block The inner peripheral edge of the lower surface of the graphite plate surrounds the first leakage preventing groove and is sandwiched by the upper mold, and the upper and lower molds cover the graphite plate and fix the position thereof. In the above embodiment of the invention, the insulating acid-resistant material is an epoxy resin, a poly-arylene film or an acrylic. In the above embodiment of the present invention, the second leakage preventing groove of the frame is formed in a slightly meandering shape on the inner surface edge of each of the cover plates.

Please refer to FIG. 1 to FIG. 5 for an exploded view of the overall structure of the present invention, a schematic structural view of the graphite plate of the present invention, a schematic structural view of the integrated bipolar plate of the present invention, and a structure of the cover of the present invention. The schematic view and the schematic of the present invention for integrating a graphite plate with a frame by an injection molding jig. As shown in the figure: the present invention is a bipolar plate of a flow battery and a manufacturing method thereof, comprising: First, a conductive graphite plate 11 is provided, as shown in Figures 2 and 5, the conductive graphite plate 11 comprises An upper surface 111 and a lower surface 112, and a plurality of first leakage preventing grooves 113 are formed on the periphery of the upper and lower surfaces 111, 112. Next, an injection molding jig is provided to sandwich the inner edge of the graphite plate 11 for positioning. Then, using the injection molding jig, an insulating acid-proof material such as an epoxy resin, a polyimide or an Acrylic is injection-molded around the graphite plate 11 to form a frame 12, and on the frame 12 A plurality of branch channels 121 are formed by injection to form an integrated bipolar plate 1, as shown in FIG. The outer periphery of the frame 12 is further provided with a sealing groove 122, and a sealing gasket 14 can be embedded in the sealing groove 122 of the integrated bipolar plate 1 to form a sealing structure. Finally, a plurality of cover plates 13 are mounted on the frame 12 and over the plurality of branch flow channels 121, and a second leakage preventing groove 131 is formed on the contact surface of each of the cover plates 13 and the frame 12. As shown in FIG. 4, the second leakage preventing groove 131 is formed in a meander shape on the inner surface edge of each of the cover plates 13. If so, a new bipolar plate of a liquid flow battery and a manufacturing method thereof are constructed by the above disclosed process and structure. The injection molding jig 2 is the AA cross-sectional view of FIG. 3, and the injection molding jig 2 includes an upper mold 21 and a lower mold 22 corresponding to the upper mold 21, as shown in FIG. The cavity of the upper mold 21 and the cavity of the lower mold 22 cooperate with the shape of the half of the integrated bipolar plate 1 to have a symmetrical structure. The upper and lower molds 21 and 22 are respectively provided with upper and lower mold holes 211 and 221 and upper and lower positioning blocks 212 and 222 corresponding to the shape of the integrated bipolar plate 1. In one embodiment, the present invention designs two first leak-proof grooves 113 on the periphery of the reaction area of the frame 12 and the graphite plate 11. As shown in FIG. 2, the graphite plate 11 and the insulating acid-resistant material can be added. Bonding property to prevent the electrolyte from flowing on both sides of the bipolar plate 1. When manufacturing, the two first leakage preventing grooves 113 on the periphery of the graphite plate 11 have the function of assisting the positioning and clamping of the injection molding jig 2, so that the upper and lower molds 21 and 22 sandwich the graphite plate 11 correspondingly. The upper positioning block 212 is positioned on the side of the first leakage preventing groove 113 surrounded by the inner circumference of the upper surface 111 of the graphite plate 11 and is clamped by the lower mold 22, and the lower positioning block 222 is positioned on the lower surface 112 of the graphite plate 11. The inner peripheral edge surrounds the first leakage preventing groove 113 and is sandwiched by the upper mold 21, and the graphite plate 11 is covered by the upper and lower dies 21, 22 and fixed in position as shown in Fig. 5. In addition, the present invention also designs a cover 13 above the branch flow path 121, as shown in FIG. 4, and is placed above the branch flow paths 121 to prevent the electrolyte from directly contacting the protons in the branch flow paths 121. The exchange of the membrane causes a decrease in the life of the proton exchange membrane, and prevents the proton exchange membrane from sinking into the branch flow channels 121, causing clogging of the electrolyte. A second leakage preventing groove 131 is also provided on the contact surface of the cover plate 13 with the frame 12, thereby preventing electrolyte from oozing out from the cover plate 13. Therefore, in the present invention, the two insulating frames which are originally covered by the sandwiching method are coated, and the insulating and acid-resistant material is formed around the graphite plate by injection molding to form an integrated bipolar plate. The composite groove design is adopted around the graphite plate to increase the bonding strength between the insulating acid-resistant material and the graphite plate and reduce the risk of electrolyte leakage. The branch flow path designed to reduce the divergence current will also be fabricated on the frame by injection molding. If the integrated bipolar plate is applied to the stack, the leakage of the electrolyte can be effectively reduced, and the number of parts and the time-consuming assembly process can be greatly reduced, thereby effectively reducing the processing and assembly costs. Comparing Figures 1 and 6, it can be seen that the integrated bipolar plate simplifies a very large number of components compared to conventional bipolar plates. Therefore, the present invention has the advantages of reducing the cost of the battery by simplifying the structural design, thereby facilitating the application of the all-vanadium battery to the energy storage system. In summary, the present invention is a bipolar plate for a liquid flow battery and a manufacturing method thereof, which can effectively improve various disadvantages of the conventional use, and adopts an injection molding method to form an insulating acid-proof material around a graphite plate to form an integrated bipolar plate. And adopting a composite groove design around the graphite plate to increase the bonding strength between the insulating acid-resistant material and the graphite plate and reduce the risk of leakage of the electrolyte, and also reduce the branch current path designed by the injection molding method to reduce the divergence current. It is also fabricated on the frame to achieve a significant reduction in the number of parts and time-consuming assembly procedures, and to reduce the cost of processing and assembly, thereby making the life of the present invention more progressive, more practical, and more in line with the needs of the user. Has met the requirements of the invention patent application, and filed a patent application according to law. However, the above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto; therefore, the simple equivalent changes and modifications made in accordance with the scope of the present invention and the contents of the invention are modified. All should remain within the scope of the invention patent.

(part of the invention)
1‧‧‧Integrated bipolar plates 11.‧‧Graphite plates 111‧‧‧ Upper surface 112‧‧‧ Lower surface 113‧‧‧ First leak-proof groove 12‧‧‧Frame 121‧‧‧ branch runner 122 ‧‧‧Seaning groove 13‧‧‧ Cover 131‧‧‧Second leak-proof groove 14‧‧‧Sealing washer 2‧‧‧ Injection molding jig 21‧‧‧Upper mold 211‧‧‧Upper hole 212‧‧ ‧Upper positioning block 22‧‧‧ Lower mold 221‧‧‧ Lower mold hole 222‧‧‧ positioning block (customized part)
3‧‧‧ Bipolar plate 31‧‧‧Insulation frame 311‧‧‧ branch flow channel 32‧‧‧ graphite plate 33‧‧‧ airtight gasket

Fig. 1 is an exploded perspective view showing the overall structure of the present invention. Fig. 2 is a schematic view showing the structure of the graphite sheet of the present invention. Figure 3 is a schematic view showing the structure of the integrated bipolar plate of the present invention. Figure 4 is a schematic view showing the structure of the cover of the present invention. Fig. 5 is a schematic view showing the integration of a graphite plate and a frame by an injection molding jig according to the present invention. Figure 6 is a schematic diagram of the components of the conventional bipolar plate structure.

1‧‧‧Integrated bipolar plates

11‧‧‧ Graphite board

12‧‧‧Frame

121‧‧‧ branch runner

122‧‧‧sealing groove

13‧‧‧ Cover

131‧‧‧Second leak-proof groove

14‧‧‧Sealing washer

Claims (11)

A method for manufacturing a bipolar plate of a flow battery, comprising at least the following steps: (A) providing a conductive graphite plate comprising an upper surface and a lower surface, and forming a plurality of first defenses on the periphery of the upper and lower surfaces (B) providing an injection molding jig for holding the inner edge of the graphite plate for positioning; (C) using the injection molding jig, injection molding an insulating acid-resistant material around the graphite plate to form a frame, and Forming a plurality of branch flow paths together to form an integrated bipolar plate; and (D) mounting a plurality of cover plates on the frame and covering the plurality of branch flow paths, and each cover plate and A second leakage preventing groove is formed on the contact surface of the frame. The method for manufacturing a bipolar plate of a flow battery according to claim 1, wherein the injection molding jig comprises an upper die and a die corresponding to the upper die, and the upper die is shaped The cavity and the cavity of the lower die cooperate with the shape of the half of the integrated bipolar plate to have a symmetrical structure. According to the method for manufacturing a bipolar plate of a flow battery according to claim 2, wherein the upper surface of the upper and lower molds are respectively provided with upper and lower mold holes corresponding to the shape of the integrated bipolar plate. And the upper and lower positioning blocks, the upper and lower molds are correspondingly clamped to the graphite plate in the integrated bipolar plate, so that the upper positioning block is positioned on the first leakage preventing groove edge around the inner periphery of the surface of the graphite plate And being clamped by the lower mold, and the lower positioning block is positioned on the first leakage preventing groove edge surrounded by the inner circumference of the lower surface of the graphite plate and is clamped by the upper mold, and the graphite is coated by the upper and lower molds. Board and fix its position. The method for manufacturing a bipolar plate of a flow battery according to claim 1, wherein the insulating acid-resistant material is an epoxy resin, a polyimide or an Acrylic. The method for manufacturing a bipolar plate of a flow battery according to the first aspect of the invention, wherein the second leakage preventing groove is formed in a slightly meandering shape on an inner surface edge of each of the cover plates. A bipolar plate for a liquid flow battery, comprising: an integrated bipolar plate comprising a graphite plate having a plurality of first leakage preventing grooves around, and a plurality of strips arranged around the graphite plate by injection molding a frame on the leakage preventing groove, and the frame is provided with a plurality of branch flow channels; and a plurality of cover plates are disposed on the frame and covering the plurality of branch flow channels, and each cover plate and the cover plate A second leakage preventing groove is provided on the contact surface of the frame. The bipolar plate of the flow battery according to the sixth aspect of the invention, wherein the plurality of branch channels are formed by injection molding. The bipolar plate of the flow battery according to the first aspect of the patent application, wherein the integrated bipolar plate is formed by injecting an insulating acid-proof material into the graphite plate by an injection molding jig combined with an upper mold and a lower mold. An injection molding body of the frame is formed around, and a cavity of the upper mold and a cavity of the lower mold cooperate with a shape of a half of the shape of the integrated bipolar plate. According to the bipolar plate of the flow battery of claim 8, wherein the upper surface of the upper and lower molds are respectively provided with the upper and lower mold holes corresponding to the shape of the integrated bipolar plate. And positioning the block, so that the upper and lower molds correspondingly sandwich the graphite plate in the integrated bipolar plate, so that the upper positioning block is positioned on the first leakage preventing groove edge around the inner periphery of the surface of the graphite plate and The lower mold is clamped, and the lower positioning block is positioned on the first leakage preventing groove edge surrounded by the inner circumference of the lower surface of the graphite plate and is clamped by the upper mold, and the graphite plate is covered by the upper and lower molds. Fix its position. The bipolar plate of the flow battery according to claim 8, wherein the insulating acid-resistant material is epoxy resin, polyarylene film or acrylic. The bipolar plate of the flow battery according to the sixth aspect of the invention, wherein the second leakage preventing groove of the frame is formed in a slightly ㄇ shape on the inner surface edge of each of the cover plates.