A proton exchange membrane and plate-frame integrated structure for flow battery and preparation method thereof

Abstract

The present invention provides an integrated structure of a proton exchange membrane and a plate frame for a liquid flow battery and a preparation method thereof. In the method, a welding area is arranged in a first groove of a flat plate frame, and the proton exchange membrane is tightly fixed to the surface of the flat plate frame through the first groove and the second groove structure of the flat plate frame and a square annular plate frame cover to form an integrated structure. Under the condition that welding ribs and welding diaphragms are not applicable, effective sealing between the battery stack plate frame and the proton exchange membrane is achieved, and the problems of welding rib failure and welding diaphragm aging caused by long-term contact between the welding area and the electrolyte in the traditional welding process of the liquid flow battery are avoided. The method of the present invention improves the efficiency of the battery stack assembly, saves costs, has a firm structure, good sealing performance, reduces the mechanical stress generated by the plate frame during welding, prolongs the service life of the proton exchange membrane and the plate frame, improves the reliability of the liquid flow battery stack, prolongs the service life of the liquid flow battery stack, and has excellent application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage, and in particular relates to a proton exchange membrane and plate-frame integrated structure for a liquid flow battery and a preparation method thereof. Background Art

[0002] As global environmental problems worsen and concerns about resource depletion grow, it is critical to promote the use and development of renewable energy such as solar and wind energy. However, renewable energy such as solar and wind energy have intermittent and unstable generation problems and cannot be directly connected to the power grid. According to the basic situation of renewable energy generation and output, there is a demand for practical balanced power generation. To achieve this demand, appropriate electrochemical energy storage equipment must be invested in the power grid.

[0003] Electrochemical energy storage has the characteristics of pollution-free operation, high efficiency, flexible power and energy characteristics that can meet the functions of different power grids, long cycle life, low maintenance cost, and is not restricted by terrain and environment. It can directly store and release electrical energy, making it an ideal energy storage technology. Liquid flow batteries have the characteristics of low cost, long life, and high energy efficiency, and are considered to be the development direction of large-scale electrochemical energy storage. In the past 40 years of research and development, iron-chromium system liquid flow batteries have been close to full commercialization and have been widely used in emergency continuous power supply facilities, industrial batteries, electric traction, independent applications, and electric load balancing.

[0004] In the traditional welding process of liquid flow battery stacks, long-term contact between the membrane welding area and the electrolyte will lead to weld failure and welding diaphragm aging, which will directly affect the long-term stability of the liquid flow battery stack structure. At the same time, the use of welds and welding diaphragms will affect the internal resistance of the stack system to a certain extent.

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a preparation and application of an integrated proton exchange membrane and plate frame structure for a liquid flow battery. The plate frame and the proton exchange membrane are made into an integrated structure through a double-layer groove structure and a laser welding process, thereby achieving effective sealing between the battery stack plate frame and the proton exchange membrane. At the same time, the welding method of the present invention does not use welding ribs and welding diaphragms, which not only saves costs, but also achieves the long-term stability of the welding structure of the proton exchange membrane of the liquid flow battery. Summary of the invention

[0006] In view of this, in order to solve the above technical problems, the purpose of the present invention is to overcome the drawbacks of the existing flow battery stack welding technology, solve the problems of high sealing cost of the existing flow battery stack, and insufficient long-term stability caused by aging of welding ribs and welding diaphragms; provide a preparation method of an integrated proton exchange membrane and plate frame structure for a flow battery, and make the plate frame and proton exchange membrane into an integrated structure through a double-layer groove structure and a laser welding process, solving the technical problem of sealing between the stack plate frame and the proton exchange membrane. The method of the present invention is simple, improves the efficiency of the stack assembly, saves production costs, has a firm structure, good sealing performance, reduces the mechanical stress generated by the plate frame during the welding process, prolongs the service life of the proton exchange membrane and the plate frame, effectively avoids the leakage of electrolyte in the flow battery stack due to membrane welding, improves the reliability of the flow battery stack, prolongs the service life of the flow battery stack, and has excellent application prospects.

[0007] In order to achieve the above purpose, the technical solutions adopted are as follows:

[0008] A proton exchange membrane and plate-frame integrated structure for a flow battery, comprising:

[0009] A flat plate frame, a square ring plate frame cover, and a proton exchange membrane;

[0010] The plane frame is provided with double grooves around the outer edge, the first groove is provided in an annular manner around the plane of the plane frame near the outer edge to form a first annular groove, and the second groove is provided in the first groove and is provided in an annular manner along the first groove to form a second annular groove;

[0011] The square annular plate frame cover plate is arranged in cooperation with the double grooves of the plane plate frame. The square annular plate frame cover plate is provided with a platform portion in contact with the first groove, and is also provided with a convex portion extending into the second groove. When the square annular plate frame cover plate is matched with the double grooves of the plane plate frame, the platform portion is in close contact with the first groove; the convex portion is closely matched with the second groove; a whole proton exchange membrane is placed above the plane plate frame, and when the square annular plate frame cover plate is pressed into the first groove and the second groove of the plane plate frame, the proton exchange membrane is pressed into and fixed on the plane plate frame. After the proton exchange membrane is pressed into by the square annular plate frame cover plate, it does not completely cover the first groove, but completely covers the second groove, leaving the welding area in the first groove, and the welding area left in the first groove is tightly connected by a laser welding process. The proton exchange membrane is distributed in a partial area of ​​the first groove, the second groove and the plane area of ​​the plane plate frame surrounded by the first groove, and is tightly squeezed and sealed by the plane plate frame and the square annular plate frame cover plate, so as to be fixed on the surface of the plane plate frame;

[0012] The height of the first groove is not higher than that of the second groove.

[0013] Furthermore, the planar frame is thermoplastic.

[0014] A method for preparing a proton exchange membrane and plate-frame integrated structure for a flow battery is as follows:

[0015] Step S1: Selection of laser welding system: According to the characteristics of the material of the plate frame, the transmission and reflection characteristics of the laser, and the beam characteristics of different lasers, a laser welding machine is selected, and a PC is used to control the three-dimensional workbench to control the movement direction of the welded workpiece and the welding head;

[0016] Step S2: In a dust-free environment, the plane plate frame, the proton exchange membrane, and the square annular plate frame cover are stacked together in sequence, the square annular plate frame cover is on the upper layer, the plane plate frame is on the lower layer, and the proton exchange membrane is placed in the middle. After the proton exchange membrane is pressed into the square annular plate frame cover, the platform portion of the square annular plate frame cover is in close contact with the first groove of the plane plate frame; the raised portion is closely matched with the second groove of the plane plate frame; the proton exchange membrane does not completely cover the first groove, but completely covers the second groove, leaving the welding area in the first groove, and the proton exchange membrane is distributed in a partial area of ​​the first groove, the second groove, and the plane area surrounded by the first groove of the plane plate frame, and is tightly squeezed and sealed by the plane plate frame and the square annular plate frame cover, so as to be fixed on the surface of the plane plate frame, and a glass plate is placed on the top to apply a downward force;

[0017] Step S3: The laser welding machine emits an infrared laser, which passes through the square annular plate frame cover and concentrates the energy on the welding area left by the first groove of the lower opaque flat plate frame. Through laser temperature heating, the temperature of the welding area of ​​the lower flat plate frame rises and melts, stimulating the adhesion of the flat plate frame, so that the square annular plate frame cover and the flat plate frame are integrated, realizing the integrated structure of the proton exchange membrane and the plate frame.

[0018] Furthermore, the flat plate frame is a flat plate made of one or more composite materials selected from the group consisting of polyethylene, polypropylene, polyvinylidene fluoride, polystyrene, polycarbonate, polymethyl methacrylate, and polyethylene terephthalate; the square ring-belt plate frame cover is a flat plate made of one or more composite materials selected from the group consisting of polyethylene, polypropylene, polyvinylidene fluoride, polystyrene, polycarbonate, polymethyl methacrylate, and polyethylene terephthalate.

[0019] Furthermore, the flat plate frame is made of opaque material; the laser transmittance of the square ring-shaped plate frame cover is above 30%.

[0020] Furthermore, the constituent materials of the square ring-shaped plate frame cover and the flat plate frame contain at least one or more identical substances, and the mass content of the identical substances in their constituent materials should be greater than or equal to 40%.

[0021] Furthermore, the proton exchange membrane is a perfluorosulfonic acid resin membrane or a sulfonated polyetheretherketone membrane.

[0022] Furthermore, in step S1, the laser welding machine uses a semiconductor continuous laser with a wavelength of 800-980nm. The laser is a semiconductor continuous welding device. A PC is used to control the three-dimensional workbench. The welded workpiece moves in the X and Y directions, and the welding head moves in the Z direction.

[0023] Furthermore, in step S2, the downward force applied by the glass plate is 0.3-0.5 MPa.

[0024] Furthermore, in step S2, the thickness of the proton exchange membrane is 0.03-0.1 mm; the welding power between the square annular plate frame cover and the flat plate frame is 50-100 W; and the welding rate is 2-20 mm / s.

[0025] Beneficial effects:

[0026] The beneficial effects of the present invention are embodied in:

[0027] The present invention provides an integrated structure of a proton exchange membrane and a plate frame for a liquid flow battery and a preparation method thereof. In the method, a welding area is arranged in a first groove of a flat plate frame, and the proton exchange membrane is tightly fixed to the surface of the flat plate frame through the first groove and the second groove structure of the flat plate frame and a square annular plate frame cover to form an integrated structure. Under the condition that welding ribs and welding diaphragms are not applicable, effective sealing between the battery stack plate frame and the proton exchange membrane is achieved, and the problems of welding rib failure and welding diaphragm aging caused by long-term contact between the welding area and the electrolyte in the traditional welding process of the liquid flow battery are avoided. The method of the present invention improves the efficiency of the battery stack assembly, saves costs, has a firm structure, good sealing performance, reduces the mechanical stress generated by the plate frame during welding, prolongs the service life of the proton exchange membrane and the plate frame, improves the reliability of the liquid flow battery stack, prolongs the service life of the liquid flow battery stack, and has excellent application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 is a top view of a single planar bottom plate in an embodiment of the present invention;

[0030] Figure 2 It is a single-side cross-sectional front view of the square ring plate frame cover plate and the plane plate frame when assembled and matched in the embodiment of the present invention;

[0031] Figure 3 It is a front cross-sectional view of the square annular plate frame cover plate, the proton exchange membrane and the flat plate frame after being assembled and matched in an embodiment of the present invention;

[0032] Figure 4 It is a top view of the square annular plate frame cover plate, the proton exchange membrane and the flat plate frame after being assembled and matched in an embodiment of the present invention;

[0033] Among them, 1 is a plane plate frame, 2 is a square annular plate frame cover, 2-1 is a platform portion of a square annular plate frame cover, 2-2 is a raised portion of a square annular plate frame cover, 3 is a proton exchange membrane, 4 is a welding area, 5 is a first groove, and 6 is a second groove. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] Embodiment 1:

[0036] This embodiment provides an integrated proton exchange membrane and plate-frame structure for a liquid flow battery and a preparation method thereof, wherein an integrated proton exchange membrane and plate-frame structure for a liquid flow battery is:

[0037] like Figure 1-Figure 4 As shown:

[0038] A flat plate frame, a square ring plate frame cover, and a proton exchange membrane;

[0039] like Figure 1 As shown, a double groove is arranged around the plane frame near the outer edge, the first groove is arranged in an annular manner around the plane of the plane frame near the outer edge to form a first annular groove, and the second groove is arranged in the first groove and arranged in an annular manner along the first groove to form a second annular groove;

[0040] like Figure 2As shown, the square annular plate frame cover plate is arranged in cooperation with the double grooves of the plane plate frame. The square annular plate frame cover plate is provided with a platform portion in contact with the first groove, and is also provided with a convex portion extending into the second groove. When the square annular plate frame cover plate is matched with the double grooves of the plane plate frame, the platform portion is in close contact with the first groove; the convex portion is closely matched with the second groove; a whole proton exchange membrane is placed above the plane plate frame, and when the square annular plate frame cover plate is pressed into the first groove and the second groove of the plane plate frame, the proton exchange membrane is pressed in and fixed on the plane plate frame. After the proton exchange membrane is pressed in by the square annular plate frame cover plate, it does not completely cover the first groove, but completely covers the second groove, leaving the welding area in the first groove, and the welding area left in the first groove is tightly connected by a laser welding process. The proton exchange membrane is distributed in a partial area of ​​the first groove, the second groove and the plane area surrounded by the first groove of the plane plate frame, and is tightly squeezed and sealed by the plane plate frame and the square annular plate frame cover plate, so as to be fixed on the surface of the plane plate frame; as shown Figure 4 As shown;

[0041] The height of the first groove is not higher than that of the second groove.

[0042] The preparation method comprises the following steps:

[0043] Step S1: Selection of laser welding system: Based on the characteristics of the material of the plate frame, the transmission and reflection characteristics of the laser, and the beam characteristics of different lasers, a semiconductor continuous laser with a wavelength of 980nm is selected for welding. The laser is a semiconductor continuous welding device. A PC is used to control the three-dimensional workbench. The workpiece to be welded moves in the X and Y directions, and the welding head moves in the Z direction.

[0044] Step S2: Use anhydrous ethanol to wipe Figure 2 The positions of the first groove and the second groove of the plane plate frame, as well as the platform portion and the raised portion of the square annular plate frame cover, are shown, waiting for the anhydrous ethanol to completely evaporate.

[0045] like Figure 2 and Figure 3As shown, in a dust-free environment, a flat plate frame is placed on a workbench, and the flat plate frame, the perfluorosulfonic acid resin film, and the square ring-belt plate frame cover are stacked together in sequence, the square ring-belt plate frame cover is on the upper layer, the flat plate frame is on the lower layer, and the perfluorosulfonic acid resin film is placed in the middle. After the perfluorosulfonic acid resin film is pressed into the square ring-belt plate frame cover, the platform portion of the square ring-belt plate frame cover is in close contact with the first groove of the flat plate frame; the raised portion is closely matched with the second groove of the flat plate frame; the perfluorosulfonic acid resin film does not completely cover the first groove, but completely covers the second groove, leaving the welding area in the first groove, and the perfluorosulfonic acid resin film is distributed in a partial area of ​​the first groove, the second groove, and the plane area surrounded by the first groove of the flat plate frame, and is tightly squeezed and sealed by the flat plate frame and the square ring-belt plate frame cover, so as to be fixed on the surface of the flat plate frame, and a glass plate is placed on the top, and a downward force is applied, and the pressure is 0.3MPa;

[0046] Step S3: Start the welding machine with a power of 50W and a speed of 20mm / s. Under the lifting action of the cylinder, the glass plate is pressed to apply a pressure of 0.3MPa. The laser welding machine emits an infrared laser, which passes through the square ring-belt plate frame cover and concentrates the energy on the welding area left by the first groove of the lower opaque flat plate frame. Through laser temperature heating, the temperature of the welding area of ​​the lower flat plate frame rises and melts, stimulating the adhesion of the flat plate frame, so that the square ring-belt plate frame cover and the flat plate frame are integrated. After welding, the pressure is maintained for 15s to improve the adhesion and sealing. Finally, cool the laser and turn off the laser to allow the welded diaphragm to cool and solidify. To achieve an integrated structure of the proton exchange membrane and the plate frame, such as Figure 4 shown.

[0047] In summary, the present invention provides an integrated structure of a proton exchange membrane and a plate frame for a liquid flow battery and a preparation method thereof. In this method, the welding area is arranged in the first groove of the flat plate frame, and the proton exchange membrane is tightly fixed to the surface of the flat plate frame through the first groove and the second groove structure of the flat plate frame and the square annular plate frame cover to form an integrated structure. Under the condition that welding ribs and welding diaphragms are not applicable, effective sealing between the battery stack plate frame and the proton exchange membrane is achieved, and the problems of welding rib failure and welding diaphragm aging caused by long-term contact between the welding area and the electrolyte in the traditional welding process of the liquid flow battery are avoided. The method of the present invention improves the efficiency of the battery stack assembly, saves costs, has a firm structure, good sealing performance, reduces the mechanical stress generated by the plate frame during the welding process, prolongs the service life of the proton exchange membrane and the plate frame, improves the reliability of the liquid flow battery stack, and prolongs the service life of the liquid flow battery stack, and has excellent application prospects.

[0048] The above description is not intended to impose any form of limitation on the present invention. Although the present invention has been disclosed through the above embodiments, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A proton exchange membrane and plate-frame integrated structure for a flow battery, characterized in that: The integrated structure comprises: A flat plate frame, a square ring plate frame cover, and a proton exchange membrane; The plane frame is provided with double grooves around the outer edge, the first groove is provided in an annular manner around the plane of the plane frame near the outer edge to form a first annular groove, and the second groove is provided in the first groove and is provided in an annular manner along the first groove to form a second annular groove; The square annular plate frame cover plate is matched with the double groove of the plane plate frame. The square annular plate frame cover plate is provided with a platform portion in contact with the first groove, and is also provided with a convex portion extending into the second groove. When the square annular plate frame cover plate is matched with the double groove of the plane plate frame, the platform portion is in close contact with the first groove; the convex portion is closely matched with the second groove; a whole proton exchange membrane is placed above the plane plate frame, and when the square annular plate frame cover plate is pressed into the first groove and the second groove of the plane plate frame, the proton exchange membrane is pressed into and fixed on the plane plate frame. After the proton exchange membrane is pressed into by the square annular plate frame cover plate, it does not completely cover the first groove, but completely covers the second groove, leaving the welding area in the first groove, and the welding area left in the first groove is tightly connected by a laser welding process, so that the square annular plate frame cover plate is integrated with the plane plate frame, and the proton exchange membrane is distributed in a partial area of ​​the first groove, the second groove and the plane area of ​​the plane plate frame surrounded by the first groove, and is tightly squeezed and sealed by the plane plate frame and the square annular plate frame cover plate, so as to be fixed on the surface of the plane plate frame; The welding area is the portion of the first groove of the planar plate frame that is not covered by the proton membrane, that is, the portion where the platform portion of the square annular plate frame cover plate directly contacts the first groove of the planar plate frame; The height of the first groove is not higher than that of the second groove; The planar plate frame is thermoplastic.

2. A method for preparing a proton exchange membrane and plate-frame integrated structure for a flow battery as claimed in claim 1, characterized in that: The preparation method is: Step S1: Selection of laser welding system: According to the characteristics of the material of the plate frame, the transmission and reflection characteristics of the laser, and the beam characteristics of different lasers, a laser welding machine is selected, and a PC is used to control the three-dimensional workbench to control the movement direction of the welded workpiece and the welding head; Step S2: In a dust-free environment, the plane plate frame, the proton exchange membrane, and the square annular plate frame cover are stacked together in sequence, the square annular plate frame cover is on the upper layer, the plane plate frame is on the lower layer, and the proton exchange membrane is placed in the middle. After the proton exchange membrane is pressed into the square annular plate frame cover, the platform portion of the square annular plate frame cover is in close contact with the first groove of the plane plate frame; the raised portion is closely matched with the second groove of the plane plate frame; the proton exchange membrane does not completely cover the first groove, but completely covers the second groove, leaving the welding area in the first groove, and the proton exchange membrane is distributed in a partial area of ​​the first groove, the second groove, and the plane area surrounded by the first groove of the plane plate frame, and is tightly squeezed and sealed by the plane plate frame and the square annular plate frame cover, so as to be fixed on the surface of the plane plate frame, and a glass plate is placed on the top to apply a downward force; Step S3: The laser welding machine emits an infrared laser, which passes through the square annular plate frame cover and concentrates the energy on the welding area left by the first groove of the lower opaque flat plate frame. Through laser temperature heating, the temperature of the welding area of ​​the lower flat plate frame rises and melts, stimulating the adhesion of the flat plate frame, so that the square annular plate frame cover and the flat plate frame are integrated, realizing the integrated structure of the proton exchange membrane and the plate frame.

3. A method for preparing a proton exchange membrane and plate-frame integrated structure for a flow battery as claimed in claim 2, characterized in that: The flat plate frame is a flat plate made of one or more composite materials selected from the group consisting of polyethylene, polypropylene, polyvinylidene fluoride, polystyrene, polycarbonate, polymethyl methacrylate, and polyethylene terephthalate; the square ring-belt plate frame cover is a flat plate made of one or more composite materials selected from the group consisting of polyethylene, polypropylene, polyvinylidene fluoride, polystyrene, polycarbonate, polymethyl methacrylate, and polyethylene terephthalate.

4. A method for preparing a proton exchange membrane and plate-frame integrated structure for a flow battery as claimed in claim 2, characterized in that: The flat plate frame is made of opaque material; the laser transmittance of the square ring-shaped plate frame cover is above 30%.

5. A method for preparing a proton exchange membrane and plate-frame integrated structure for a flow battery as claimed in claim 2, characterized in that: The constituent materials of the square ring-shaped plate frame cover and the flat plate frame contain at least one or more identical substances, and the mass content of the identical substances in their constituent materials should be greater than or equal to 40%.

6. A method for preparing a proton exchange membrane and plate-frame integrated structure for a flow battery as claimed in claim 2, characterized in that: The proton exchange membrane is selected from perfluorosulfonic acid resin membrane or sulfonated polyetheretherketone membrane.

7. The method for preparing a proton exchange membrane and plate-frame integrated structure for a flow battery as claimed in claim 2, characterized in that: In step S1, the laser welding machine uses a semiconductor continuous laser with a wavelength of 800-980nm. The laser is a semiconductor continuous welding device. A PC is used to control the three-dimensional workbench. The welded workpiece moves in the X and Y directions, and the welding head moves in the Z direction.

8. The method for preparing a proton exchange membrane and plate-frame integrated structure for a flow battery as claimed in claim 2, characterized in that: In step S2, the downward force applied by the glass plate is 0.3-0.5 MPa.

9. A method for preparing a proton exchange membrane and plate-frame integrated structure for a flow battery as claimed in claim 2, characterized in that: In the step S2, the thickness of the proton exchange membrane is 0.03-0.1 mm; the welding power between the square annular plate frame cover and the flat plate frame is 50-100 W; and the welding rate is 2-20 mm / s.

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