Combined electrode frame structure of replaceable bipolar plate of all-vanadium redox flow battery

Abstract

The invention belongs to the technical field of redox flow batteries, and discloses a combined electrode frame structure of a replaceable bipolar plate of an all-vanadium redox flow battery, which comprises a combined structure positive electrode frame, sealing rubber, a bipolar plate and a combined structure negative electrode frame, the use of sealant is reduced by adopting a mechanical sealing mode, the cost is greatly saved, the sealing effect between the electrode frame and the bipolar plate is improved by adopting a plurality of layers of sealing grooves, the bipolar plate can be directly replaced without influencing other parts after being damaged in operation, the waste of materials is reduced, the bipolar plate is arranged in the electrode frame, and the service life of the bipolar plate is prolonged. The use amount of the bipolar plate is reduced by 30%, the overall thickness of the electric pile is reduced, the voltage efficiency of the electric pile is improved, and the energy efficiency of the electric pile is improved; according to the design, a bipolar plate tab for measuring the voltage of a single battery is reserved, so that the detection is convenient.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid flow batteries, and relates to an electrode frame applied to an all-vanadium liquid flow battery stack, and specifically to a combined electrode frame structure with replaceable bipolar plates for an all-vanadium liquid flow battery. Background Art

[0002] Renewable energy such as solar energy, wind energy, and tidal energy are widely used in power generation facilities. However, renewable energy has disadvantages such as randomness, intermittency, and large volatility, which will lead to reduced power quality and reliability of the distribution network, thereby affecting the stability and safety of the power system. Therefore, it is necessary to store and release electricity in the form of energy conversion.

[0003] Energy storage systems can be divided into two categories according to their working principles: chemical energy storage and physical energy storage. Physical energy storage includes flywheel energy storage, water pumping energy storage and compressed air. Chemical energy storage mainly includes various types of energy storage batteries, common types include lead-acid batteries, lithium-ion batteries, flow batteries and sodium-sulfur batteries.

[0004] All-vanadium liquid flow batteries have long service life, high energy conversion efficiency, flexible design, large energy storage capacity, deep discharge, low maintenance costs, and efficient and convenient thermal management. They can be used as energy storage equipment for clean energy such as hydropower, wind power, and solar power, and can also be used to smooth the load of the power grid, thereby ensuring the orderly operation of the power grid. All-vanadium liquid flow storage batteries are therefore very suitable as large-scale energy storage equipment.

[0005] The existing all-vanadium liquid flow battery stack structure includes: end plate, insulating plate, current collecting plate, bipolar plate, sealant, electrode frame, sealant, electrode, ion membrane, electrode, sealant, electrode frame, sealant, bipolar plate, current collecting plate, insulating plate, and end plate. The role of sealant between various components is to prevent leakage inside and outside the battery. The use of sealant in the stack structure is relatively large, and the volume of the stack is increased to a certain extent. The use of sealant will increase the stack assembly process and the risk of stack leakage, and increase the cost of stack assembly.

[0006] The main function of the bipolar plate in a liquid flow battery is to isolate the positive and negative electrolytes between adjacent cells and to collect the current generated by the electrode reactions on both sides of the bipolar plate.

[0007] The existing sealing methods of electrode frames and bipolar plates mostly use sealants or laser welding. Sealant is easily leaked due to the influence of temperature and curing speed. Laser welding sealing technology is not yet mature in the field of liquid flow batteries. In addition, the bipolar plates integrated by the above method do not have pole ears for voltage measurement. Problems with the sealing of the bipolar plates will cause the positive and negative electrolytes to communicate with each other and short-circuit the battery. If the bipolar plate is damaged during operation, the materials such as the electrode frame of the battery composed of the above sealing method will fail on a large scale, resulting in material waste.

[0008] CN215933654U discloses a vanadium liquid flow battery stack structure, including a left end plate, a liquid inlet plate, a left current collecting plate, a left frame plate, a bipolar plate, a middle frame plate, a bipolar plate fixing ring, a flow channel sealing plate, a right frame plate, a right current collecting plate and a right end plate stacked in sequence; the left frame plate, the middle frame plate and the right frame plate are connected by a mortise and tenon structure to form an electrode frame; the bipolar plate, the bipolar plate fixing ring and the flow channel sealing plate are embedded in the electrode frame to form an integrated electrode structure, and the integrated electrode structure is sealed by point silicone. However, the mortise and tenon structure is mainly fixed by snapping, and a mortise and tenon groove is opened on the bipolar plate, which has the risk of leakage and is difficult to disassemble. Summary of the invention

[0009] In order to overcome the shortcomings of the existing prior art, the present invention provides a combined electrode frame with replaceable bipolar plates. Compared with the existing technology, the bipolar plates are sealed by using sealing rubber instead of glue materials or welding. After being compressed, the sealing rubber can produce a certain compression ratio with the bipolar plate, and the design of multiple sealing grooves can effectively prevent leakage. When the bipolar plate is damaged, it can be directly replaced without damaging the remaining components. In terms of testing, the pole ears of the bipolar plate are retained for measuring the voltage of a single battery cell; the bipolar plate is built into the electrode frame, and the thickness of the bipolar plate is reduced in terms of the thickness of the battery stack, so that the overall thickness of the battery stack is reduced, which reduces the ohmic polarization of the battery stack to a certain extent and improves the energy efficiency of the battery stack.

[0010] The above object of the present invention is achieved through the following technical solutions:

[0011] A combined electrode frame structure with replaceable bipolar plates for an all-vanadium liquid flow battery comprises a combined positive electrode frame, sealing rubber, bipolar plates and a combined negative electrode frame.

[0012] Furthermore, the backs of the combined positive electrode frame and the combined negative electrode frame are both provided with sealing grooves for fixing the position of the sealing rubber.

[0013] Furthermore, the number of sealing grooves ranges from 2 to 8.

[0014] Furthermore, the cross section of the sealing rubber is preferably any one of a circle, an arch, a regular trapezoid and an inverted trapezoid.

[0015] Furthermore, the combined structure is a mortise and tenon structure, which adopts a sliding dovetail tenon method, and a protruding head tenon is provided on the back of the positive electrode frame of the mortise and tenon structure, and a concave tail tenon is provided on the back of the negative electrode frame of the mortise and tenon structure.

[0016] Furthermore, the combined structure is a bonding structure, and the positive and negative electrode frames are fixed by means of sealant.

[0017] Furthermore, the bonding position of the bonding structure is the bonding groove on the back of the positive electrode frame of the bonding structure and the negative electrode frame of the bonding structure.

[0018] Furthermore, the angle of the raised tenon is between 45° and 85°.

[0019] Furthermore, the tenon has a draft angle, and the draft angle ranges from 20′ to 60′.

[0020] Furthermore, the materials of the bipolar plates include metal materials, graphite materials and carbon-plastic composite materials.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The replaceable bipolar plate combined electrode frame structure described in the present invention adopts mechanical sealing to reduce the use of sealant, greatly saving costs, and the design adopts multi-layer sealing grooves to improve the sealing effect between the electrode frame and the bipolar plate. If the bipolar plate is damaged during operation, it can be directly replaced without affecting other components, reducing material waste. The bipolar plate is built into the electrode frame, and the amount of bipolar plate is reduced by 30%. At the same time, the overall thickness of the battery stack is reduced, thereby improving the voltage efficiency of the battery stack and the energy efficiency of the battery stack. This design retains the bipolar plate ears used to measure the voltage of a single battery cell, which is convenient for detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is an exploded schematic diagram of a replaceable bipolar plate combined mortise and tenon structure electrode frame;

[0024] Figure 2 It is a schematic diagram of the assembly of the mortise and tenon structure;

[0025] Figure 3 is a schematic rear view of a positive electrode frame of a mortise and tenon structure;

[0026] Figure 4 It is a schematic diagram of the positive and negative electrode frames of the mortise and tenon structure viewed from above;

[0027] Figure 5 It is a schematic diagram of a positive electrode frame of a mortise and tenon structure with a draft angle;

[0028] Figure 6 It is an exploded schematic diagram of an electrode frame with a replaceable bipolar plate combined bonding structure;

[0029] Figure 7 is a schematic rear view of a positive electrode frame of a bonding structure;

[0030] Figure 8 is a cross-sectional view of the sealing rubber;

[0031] Markings in the figure: 1-mortise and tenon structure positive electrode frame, 2-sealing rubber, 3-bipolar plate, 4-mortise and tenon structure negative electrode frame, 5-bonding structure positive electrode frame, 6-bonding structure negative electrode frame. DETAILED DESCRIPTION

[0032] The present invention is described in detail below by specific examples, but the protection scope of the present invention is not limited. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can be obtained from commercial channels.

[0033] The present invention discloses a replaceable bipolar plate combined electrode frame. The design of the electrode frame improves the sealing effect of the bipolar plate. After the bipolar plate is damaged, it can be replaced without affecting other components. The bipolar plate is built into the electrode frame, and the use of the bipolar plate is reduced by 30%. At the same time, the overall thickness of the battery stack is reduced, and the energy efficiency of the battery stack is improved.

[0034] As attached Figure 1 The figure shows an isometric diagram of a replaceable bipolar plate combined electrode frame. The principle is to place the bipolar plate between the positive and negative electrode frames of the battery, and use the deformation of the sealing rubber on the electrode frame under pressure as the seal between the bipolar plate and the electrode frame. The materials that make up the bipolar plate include metal materials, graphite materials and carbon-plastic composite materials.

[0035] Example 1

[0036] As attached Figure 2-Figure 5 The figure shows a schematic diagram of a replaceable bipolar plate combined mortise and tenon structure electrode frame, including a mortise and tenon structure positive electrode frame 1, a sealing rubber 2, a bipolar plate 3 and a mortise and tenon structure negative electrode frame 4. The mortise and tenon structure adopts a sliding dovetail tenon method, and a raised head tenon on the back of the mortise and tenon structure positive electrode frame 1 matches with a concave tail tenon on the back of the mortise and tenon structure negative electrode frame 4, wherein the raised head tenon angle is 45 to 85 degrees, so that it has a certain mechanical strength, and the attached Figure 5 As shown, in order to facilitate the installation of the bipolar plate, the head tenon has a certain draft angle, and the draft angle range is 20'-60', while limiting its positional freedom. The positive and negative electrode frames do not need to be completely sealed, and only the relative positions of the two need to be fixed. After the battery stack is tightened as a whole, it will naturally fit and be pressed due to the greater pressure. There are sealing grooves on the back of the two electrode frames to fix the position of the sealing rubber. The number of sealing grooves can be determined according to the size of the bipolar plate to be placed. The number of sealing grooves ranges from 2 to 8. The number of sealing grooves required for larger bipolar plates increases accordingly. The groove depth can be determined according to the thickness of the sealing rubber. After the sealing rubber on the two electrode frames is completed, a certain gap must be left between them to ensure that the bipolar plate can be placed in it and have a certain friction resistance.

[0037] Example 2

[0038] As attached Figure 6 and attached Figure 7 The figure shows a schematic diagram of a replaceable bipolar plate combined bonding structure electrode frame, including a sealing rubber 2, a bipolar plate 3, a bonding structure positive electrode frame 5 and a bonding structure negative electrode frame 6. The bonding structure uses a sealant to fix the positive and negative electrode frames, and the bonding position is the bonding groove on the back of the electrode frame.

[0039] As attached Figure 8 The figure shows the cross section of the sealing rubber. There are many different types of sealing rubber. Figure 8 As shown, from left to right are circular, arched, regular trapezoidal and inverted trapezoidal. Different sealing structures are used in many different occasions. Circular and arched shapes are mostly used in the experimental stage, where the bipolar plates are small in size and need to be frequently assembled and disassembled and are subjected to less pressure. The regular trapezoidal and inverted trapezoidal shapes are surface contact, so they can withstand greater pressure than the above two shapes and are mostly used in occasions where the bipolar plates are large in size and are subjected to greater pressure.

[0040] The above-described embodiments are only preferred embodiments of the present invention, but not all feasible embodiments of the present invention. For those skilled in the art, any obvious changes made thereto without departing from the principles and spirit of the present invention should be considered to be included in the scope of protection of the claims of the present invention.

Claims

1. A combined electrode frame structure with replaceable bipolar plates for an all-vanadium liquid flow battery, characterized in that: It comprises a combined structure positive electrode frame, a sealing rubber (2), a bipolar plate (3) and a combined structure negative electrode frame.

2. The combined electrode frame structure of the all-vanadium liquid flow battery with replaceable bipolar plates according to claim 1 is characterized in that: The backs of the combined structure positive electrode frame and the combined structure negative electrode frame are both provided with sealing grooves for fixing the position of the sealing rubber (2).

3. The combined electrode frame structure of the all-vanadium liquid flow battery with replaceable bipolar plates according to claim 2 is characterized in that: The number of sealing grooves ranges from 2 to 8.

4. The combined electrode frame structure of the all-vanadium liquid flow battery with replaceable bipolar plates according to claim 1 is characterized in that: The cross section of the sealing rubber (4) is any one of a circle, an arch, a regular trapezoid and an inverted trapezoid.

5. The combined electrode frame structure of the all-vanadium liquid flow battery with replaceable bipolar plates according to claim 1 is characterized in that: The combined structure is a mortise and tenon structure, which adopts a sliding dovetail tenon method. A convex head tenon is provided on the back of the mortise and tenon structure positive electrode frame (1), and a concave tail tenon is provided on the back of the mortise and tenon structure negative electrode frame (4).

6. The combined electrode frame structure of the all-vanadium liquid flow battery with replaceable bipolar plates according to claim 1 is characterized in that: The combined structure is a bonding structure, and the positive and negative electrode frames are fixed by means of sealant.

7. The combined electrode frame structure of the all-vanadium liquid flow battery with replaceable bipolar plates according to claim 6 is characterized in that: The bonding position of the structure is the bonding groove on the back of the bonding structure positive electrode frame (5) and the bonding structure negative electrode frame (6).

8. The combined electrode frame structure of the all-vanadium liquid flow battery with replaceable bipolar plates according to claim 5 is characterized in that: The angle of the raised tenon is between 45 and 85 degrees.

9. The combined electrode frame structure of the all-vanadium liquid flow battery with replaceable bipolar plates according to claim 5 is characterized in that: The head tenon has a draft angle, and the draft angle ranges from 20'-60'.

10. The combined electrode frame structure of the all-vanadium liquid flow battery with replaceable bipolar plates according to claim 1 is characterized in that: The material of the bipolar plate (3) includes metal material, graphite material and carbon-plastic composite material.

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