System for preparing vanadium electrolyte through cathode and anode shunting type electrolysis

Abstract

The system for preparing the vanadium electrolyte through cathode and anode shunting type electrolysis comprises an electrolysis device, the electrolysis device comprises a cathode part and an anode part, and the cathode part and the anode part are separated through a proton exchange membrane; the cathode part comprises an end plate, an insulating plate, a collector plate, a fluid frame, a cathode electrode and a sealing gasket which are sequentially mounted in a stacked manner, a cathode flow channel is formed in the side face of the side, attached to the cathode electrode, of the fluid frame, the cathode flow channel is of an open slot type, a plurality of shunt columns are arranged on the cathode flow channel in parallel at intervals, and the shunt columns are connected with the end plate. And one end of the cathode runner is a cathode electrolyte inlet, and the other end of the cathode runner is a cathode electrode liquid outlet. By adopting the system for preparing the vanadium electrolyte through cathode and anode shunt type electrolysis, the preparation energy consumption is reduced, and the preparation efficiency is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of batteries, and particularly relates to a system for preparing vanadium electrolyte by cathode and anode shunt electrolysis. Background Technique

[0002] The all-vanadium redox flow battery has the advantages of independent design of capacity and power, high safety level, long service life, good design flexibility, environmental friendliness, etc., making the all-vanadium redox flow battery energy storage technology stand out among various energy storage technologies and is generally considered to be the most promising energy storage technology for large-scale applications.

[0003] High cost is one of the main factors restricting the large-scale application of all-vanadium redox flow batteries. It is reported that the manufacturing and operation and maintenance costs of all-vanadium redox flow battery electrolytes (vanadium electrolytes) account for 40% - 60% of the cost of all-vanadium redox flow battery energy storage systems. The main methods for preparing electrolytes are pure electrolysis method and the combination of chemical reduction and electrolysis. The pure electrolysis method is widely favored by researchers due to its advantages of not introducing impurities and being scalable.

[0004] The all-vanadium redox flow battery electrolyte generally uses sulfuric acid as the support system and vanadyl sulfate or vanadium pentoxide as the raw material. Vanadyl sulfate is expensive and difficult to prepare. Therefore, using vanadium pentoxide with low price and relatively simple preparation process as the raw material to prepare all-vanadium redox flow battery electrolyte is the most effective way to reduce the preparation cost of all-vanadium redox flow battery electrolyte. However, compared with vanadyl sulfate, vanadium pentoxide has extremely low solubility and slow dissolution rate in sulfuric acid. The national standard GB / T 37204-2018 stipulates that the vanadium ion concentration in the all-vanadium redox flow battery electrolyte is not less than 1.5 mol / L. When using vanadium pentoxide as the raw material to prepare an electrolyte with a concentration above 1.5 mol / L and using the pure electrolysis method, only a trace amount of vanadium pentoxide can naturally dissolve in sulfuric acid. Therefore, when using the pure electrolysis method to prepare all-vanadium redox flow battery electrolyte, how to electrolyze the vanadium pentoxide suspension in the electrolysis device with low energy consumption and high rate under the action of a pump is the main problem hindering the large-scale preparation of vanadium pentoxide electrolyte by the pure electrolysis method.

[0005] When using an H-type electrolytic cell to prepare a vanadium redox flow battery electrolyte with vanadium pentoxide as the raw material, the suspension is non-flowing, which will inevitably result in disadvantages such as an inferior mass transfer method and insufficient mixing of materials. This leads to the drawbacks of high energy consumption, low rate, and easy corrosion of graphite felt when using an H-type electrolytic cell to prepare the electrolyte. To overcome the above drawbacks, Patent CN200810012119.5 discloses a method and device for preparing vanadium electrolyte, but it does not consider problems such as blockage and precipitation of vanadium pentoxide suspension during the production process of the electrolyte. Liu Ran et al. once built a device for flowing electrolysis of vanadium pentoxide suspension in China for the first time, and prepared a vanadium redox flow battery electrolyte with good performance, solving the problem of uneven mixing of materials during electrolysis. However, this device has the drawbacks of slow electrolysis rate and high energy consumption, and the prospect of applying this device to large-scale preparation of electrolyte is unknown. Patent CN201520407125.3 reports a device for large-scale production of redox flow battery electrolyte. However, when using this device for macroscale preparation of electrolyte, there is no obvious improvement in the two key problems of electrolyte preparation energy consumption and rate that affect the cost of the electrolyte.

[0006] One of the key factors affecting electrolysis efficiency and energy consumption is that currently, the electrolytes at the cathode and anode are both unrestrained (i.e., freely flowing in all directions, lacking directivity) when contacting and reacting with the electrodes of the cathode and anode, and the uniformity of contact with the electrodes is poor, which to a certain extent affects the reaction efficiency and energy consumption. Utility Model Content

[0007] In view of this, the purpose of this application is to solve at least one of the above problems, and provide a system for preparing vanadium electrolyte by shunt electrolysis of cathode and anode, so as to reduce the preparation energy consumption and improve the preparation efficiency.

[0008] The present utility model solves the above problems through the following technical means:

[0009] A system for preparing vanadium electrolyte by shunt electrolysis of cathode and anode includes an electrolysis device. The electrolysis device includes a cathode part and an anode part, and the cathode part and the anode part are separated by a proton exchange membrane; the cathode part includes an end plate, an insulating plate, a current collector plate, a fluid frame, a cathode electrode, and a gasket stacked and installed in sequence. One side surface of the fluid frame that fits with the cathode electrode is provided with a cathode flow channel. The cathode flow channel is an open groove type, and a plurality of shunt columns are arranged at intervals side by side on the cathode flow channel. One end of the cathode flow channel is the cathode electrolyte inlet, and the other end is the cathode electrode liquid outlet.

[0010] Further, the anode part includes an end plate, an insulating plate, a current collector plate, an anode plate, a fluid frame, and a gasket that are stacked and installed in sequence. On one side of the fluid frame that is in contact with the anode plate, an anode flow channel is provided. The anode flow channel is an open groove type, and a plurality of shunt columns are arranged at intervals side by side on the anode flow channel. One end of the anode flow channel is an anode electrolyte inlet, and the other end is an anode electrode liquid outlet.

[0011] Further, the anode plate is a titanium plate or titanium felt coated with an iridium oxide coating or ruthenium iridium titanium.

[0012] Further, the cathode part and the anode part are stacked and fastened with fasteners.

[0013] Further, it further includes a cathode electrolyte circulation device, which includes a cathode liquid storage tank, an electrolyte delivery pipeline, and a delivery pump. Both the cathode electrolyte inlet and the cathode electrolyte outlet are communicated with the cathode liquid storage tank through the electrolyte delivery pipeline, and a delivery pump is installed on the electrolyte delivery pipeline between the cathode electrolyte inlet and the cathode liquid storage tank.

[0014] Further, it further includes an anode electrolyte circulation device, which includes an anode liquid storage tank, an electrolyte delivery pipeline, and a delivery pump. Both the anode electrolyte inlet and the anode electrolyte outlet are communicated with the anode liquid storage tank through the electrolyte delivery pipeline, and a delivery pump is installed on the electrolyte delivery pipeline between the anode electrolyte inlet and the anode liquid storage tank.

[0015] Further, it further includes a charge and discharge control system, which is electrically connected to the cathode electrode and the anode plate.

[0016] Advantages of the utility model:

[0017] (1) Using a titanium plate or titanium felt coated with an iridium oxide coating or ruthenium iridium titanium as the anode can accelerate the rate of the anodic oxygen evolution reaction while reducing the overpotential of the oxygen evolution reaction, resulting in lower energy consumption for preparing electrolytes of the same volume and concentration.

[0018] (2) According to the different characteristics and requirements of the anode and cathode reactions, a flow mode that can meet the fluid flow of the cathode and anode is adopted. The flow channels of both the cathode and anode are arranged based on the fluid frame. The flow channels have a guiding effect on the suspension, preventing it from freely spreading, ensuring the flow velocity, optimizing the flow mode, reducing the contact resistance. At the same time, it realizes the shunt supply of the cathode and anode electrode liquids, improves the uniformity of the electrolyte flow, and further reduces the energy consumption for preparing electrolytes of the same mass.

[0019] (3) Due to the existence of the cathode flow channel, the contact between vanadium ions and the proton exchange membrane is limited. Without affecting proton transfer, it can hinder the transmembrane transport of vanadium ions, reducing the raw material loss during the preparation process. Description of the Drawings

[0020] The present utility model will be further described below in conjunction with the accompanying drawings and embodiments.

[0021] Figure 1 It is a schematic diagram of a preferred embodiment of the present utility model;

[0022] Figure 2 It is an explosion schematic diagram of an electrolysis device;

[0023] Figure 3 It is a schematic diagram of a fluid frame of a cathode part. Specific embodiments

[0024] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0025] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0026] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0027] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0028] Such as Figures 1 to 3As shown in the figure, this embodiment provides a system for preparing vanadium electrolyte by cathode-anode shunt electrolysis, which includes an electrolysis device 5, a cathode electrolyte circulation device, an anode electrolyte circulation device, and a charge-discharge control system 6. The electrolysis device includes a cathode part and an anode part, and the cathode part and the anode part are separated by a proton exchange membrane. The cathode part includes an end plate 501, an insulating plate 502, a current collector plate 503, a fluid frame 506, a cathode electrode 508, and a gasket 507 that are stacked and installed in sequence. On one side of the fluid frame that fits with the cathode electrode, a cathode flow channel 5062 is provided. The cathode flow channel is an open groove type, and a plurality of shunt columns 5065 are arranged side by side and spaced apart on the cathode flow channel. One end of the cathode flow channel is a cathode electrolyte inlet 5061, and the other end is a cathode electrode liquid outlet 5064. During specific assembly, the cathode electrode fits with the cathode flow channel, and a shunt gap is formed between adjacent shunt columns, so that the cathode electrode liquid (suspension) can be shunted, and thus the cathode electrolyte can be evenly dispersed to contact and react with the cathode electrode. In addition, since the cathode electrolyte is a suspension and the flow rate is relatively slow, a graphite plate 505 is installed between the fluid frame and the current collector plate in the cathode part to improve conductivity.

[0029] The anode part includes an end plate 501, an insulating plate 502, a current collector plate 503, an anode plate 504, a fluid frame 506, and a gasket 507 that are stacked and installed in sequence. On one side of the fluid frame that fits with the anode plate, an anode flow channel is provided. The anode flow channel is an open groove type, and a plurality of shunt columns are arranged side by side and spaced apart on the anode flow channel. One end of the anode flow channel is an anode electrolyte inlet, and the other end is an anode electrode liquid outlet. During specific assembly, the anode plate fits with the anode flow channel, and a shunt gap is formed between adjacent shunt columns, so that the anode electrode liquid (dilute sulfuric acid) can be shunted, and thus the anode electrolyte can be evenly dispersed to contact and react with the anode plate. The anode plate is a titanium plate or titanium felt plated with an iridium oxide coating or a ruthenium-iridium-titanium coating. In this embodiment, the anode plate is a titanium plate plated with an iridium oxide coating. In addition, since the proton exchange membrane is an essential component consistent with the prior art, it is not shown in the drawings, and the proton exchange membrane is clamped and fixed by an insulating gasket.

[0030] The cathode electrolyte circulation device includes a cathode storage tank 1, an electrolyte delivery pipeline 4, and a delivery pump 3. Both the cathode electrolyte inlet and the cathode electrolyte outlet are connected to the cathode storage tank through the electrolyte delivery pipeline, and a delivery pump is installed on the electrolyte delivery pipeline between the cathode electrolyte inlet and the cathode storage tank.

[0031] The anode electrolyte circulation device includes an anode storage tank 2, an electrolyte delivery pipeline, and a delivery pump. Both the anode electrolyte inlet and the anode electrolyte outlet are connected to the anode storage tank through the electrolyte delivery pipeline, and a delivery pump is installed on the electrolyte delivery pipeline between the anode electrolyte inlet and the anode storage tank.

[0032] The charge-discharge control system is electrically connected to the cathode electrode and the anode plate.

[0033] It can be understood that the cathode part and the anode part are stacked and fastened by fasteners. Preferably, positioning holes for assembling the fasteners can be opened on each assembling component, such as fluid frame positioning holes 5063 opened at the four corners of the fluid frame.

[0034] The end plate is made of stainless steel material and serves as a fastening device to bear stress; the insulating plate is machined by a numerical control machine tool from insulating PVC material and serves to separate the end plate from the current collector plate; the current collector plate is made of copper material and serves to collect current and conduct electricity; the anode plate acts as an anode electrode and serves to electrolyze water and conduct electricity; the fluid frame is made of corrosion-resistant insulating PVC plates by numerical control machining and serves to distribute the anode electrolyte and allow the anode electrolyte to flow; the gasket is made of compressible, impermeable, and insulating fluororubber flat gasket and serves to seal the fluid frame and the surfaces of the bipolar plates and fix the proton exchange membrane; the proton exchange membrane uses DuPont Nafion117 proton exchange membrane to separate the cathode and anode electrolytes and only allows hydrogen ions to pass through to form a circuit; the cathode electrode uses a graphite felt with a thickness of 4.6 mm, and the compression ratio after compression is 35%, providing reaction sites for the reduction reaction of vanadium ions with a valence of 5 in the vanadium pentoxide suspension. In this example, a graphite felt with a size of 3 cm * 3 cm is used as the cathode electrode.

[0035] In addition to the electrolysis device, the entire system is also equipped with a cathode electrolyte circulation device, an anode electrolyte circulation device, and a charge-discharge control system. During the process of electrolytic preparation of the electrolyte, by controlling the amount of electricity charged into the electrolysis device, an electrolyte with a valence of 3.5 can be accurately prepared.

[0036] In this device, the fluid frame is the most core component, and the fluid frame can realize the function of distributing the electrolyte.

[0037] The working process is as follows:

[0038] Vanadium pentoxide powder is dissolved in dilute sulfuric acid to form a vanadium pentoxide suspension. The suspension enters the cathode flow channel from the cathode liquid storage tank under the action of a delivery pump and penetrates into the cathode electrode to undergo a reduction reaction. Dilute sulfuric acid is stored in the anode liquid storage tank, and the dilute sulfuric acid enters the anode flow channel under the action of a delivery pump and undergoes an oxygen evolution reaction on the titanium plate coated with iridium oxide (anode plate).

[0039] The cathode part and the anode part of the electrolysis device are separated by a proton exchange membrane. The proton exchange membrane only allows hydrogen ions to pass through, and there is a directional transmission of electrons in the external circuit. The two together with the conductive structure in the electrolysis device form the circuit path of the electrolysis device.

[0040] The dilute sulfuric acid entering the electrolysis device undergoes an oxygen evolution reaction on the titanium plate coated with iridium oxide (Reaction Equation 1.1);

[0041] The pentavalent vanadium in the vanadium pentoxide suspension entering the electrolysis device reaction will first be reduced to tetravalent (Reaction Equation 1.2), and then return to the cathode storage tank under the action of the transfer pump, where it is mixed with the unreacted vanadium pentoxide suspension. The mixed solution of tetravalent and pentavalent vanadium is continuously pumped into the electrolysis device, and the reactions of pentavalent vanadium being reduced to tetravalent vanadium (Reaction Equation 1.2) and tetravalent vanadium being reduced to trivalent vanadium (Reaction Equation 1.3) continue to occur. The generated trivalent vanadium promotes the dissolution of pentavalent vanadium (Reaction Equation 1.4).

[0042] By controlling the electrolysis time, a 3.5-valent vanadium electrolyte can be obtained.

[0043] Reaction equation for dilute sulfuric acid in the anode storage tank:

[0044] 2H2O - 4e- → 4H + + O2 (1.1)

[0045] Reaction equation for the suspension in the cathode storage tank:

[0046]

[0047] VO 2+ + e - + 2H + → V 3+ + H2O (1.3)

[0048]

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A system for preparing vanadium electrolyte by anode-cathode split-flow electrolysis, comprising an electrolysis device, wherein the electrolysis device comprises a cathode part and an anode part, wherein the cathode part and the anode part are separated by a proton exchange membrane; characterized in that: The cathode part includes an end plate, an insulating plate, a current collecting plate, a fluid frame, a cathode electrode and a sealing gasket which are stacked in sequence. A cathode flow channel is provided on the side of the fluid frame which is in contact with the cathode electrode. The cathode flow channel is an open slot type. A plurality of diverter columns are arranged in parallel and at intervals on the cathode flow channel. One end of the cathode flow channel is a cathode electrolyte inlet, and the other end is a cathode electrode liquid outlet.

2. The system for preparing vanadium electrolyte by anode-cathode split-flow electrolysis according to claim 1, characterized in that: The anode part includes an end plate, an insulating plate, a current collecting plate, an anode plate, a fluid frame and a sealing gasket which are stacked in sequence. An anode flow channel is provided on the side of the fluid frame which is in contact with the anode plate. The anode flow channel is an open slot type. A plurality of diverter columns are arranged in parallel and at intervals on the anode flow channel. One end of the anode flow channel is an anode electrolyte inlet, and the other end is an anode electrode liquid outlet.

3. The system for preparing vanadium electrolyte by anode-cathode split-flow electrolysis according to claim 2, characterized in that: The anode plate is a titanium plate or titanium felt plated with iridium oxide coating or ruthenium iridium titanium.

4. The system for preparing vanadium electrolyte by anode-cathode split-flow electrolysis according to claim 3, characterized in that: The cathode portion and the anode portion are stacked and fastened with fasteners.

5. The system for preparing vanadium electrolyte by anode-cathode split-flow electrolysis according to claim 4, characterized in that: It also includes a cathode electrolyte circulation device, which includes a cathode liquid storage tank, an electrolyte delivery pipeline and a delivery pump. The cathode electrolyte inlet and the cathode electrolyte outlet are both connected to the cathode liquid storage tank through the electrolyte delivery pipeline, and a delivery pump is installed on the electrolyte delivery pipeline between the cathode electrolyte inlet and the cathode liquid storage tank.

6. The system for preparing vanadium electrolyte by anode-cathode split-flow electrolysis according to claim 5, characterized in that: It also includes an anode electrolyte circulation device, which includes an anode electrolyte storage tank, an electrolyte delivery pipeline and a delivery pump. The anode electrolyte inlet and the anode electrolyte outlet are both connected to the anode electrolyte storage tank through the electrolyte delivery pipeline, and a delivery pump is installed on the electrolyte delivery pipeline between the anode electrolyte inlet and the anode electrolyte storage tank.

7. The system for preparing vanadium electrolyte by anode-cathode split-flow electrolysis according to claim 6, characterized in that: Also included is a charge and discharge control system, which is electrically connected to the cathode electrode and the anode plate.

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