Concentration balance adjusting method in vanadium redox flow battery electrolyte production

Abstract

The invention belongs to the technical field of all-vanadium redox flow batteries, and particularly relates to a concentration balance adjusting method in vanadium redox flow battery electrolyte production, which comprises a catholyte storage tank, a cathode pump, an anolyte storage tank, an anode pump and a header type electrolysis device, and is characterized in that the header type electrolysis device comprises a container, a cooling fan, an electrolysis galvanic pile and an electrolysis power supply; two groups of electrolysis galvanic piles are arranged in the container side by side and are connected with an electrolysis power supply through cables; pipelines of the two groups of electrolysis galvanic piles are connected in parallel; wherein the anolyte outlet pipe of the first group of electrolysis galvanic piles is connected with the anolyte inlet pipe of the second group of electrolysis galvanic piles through an anode process switching pipe, and a pneumatic three-way ball valve is arranged at the crossed joint of the pipelines; and hydraulic stirrers are respectively arranged in the catholyte storage tank and the anolyte storage tank. The device has the beneficial effects that the efficiency of producing the electrolyte of the all-vanadium redox flow battery is improved by adopting a header type modular structure, and the problem of ion concentration balance is solved by adopting the hydraulic stirrer.

Description

Technical Field

[0001] The present invention belongs to the technical field of all-vanadium redox flow batteries, and particularly relates to a method for adjusting the concentration balance in the production of vanadium redox flow battery electrolytes. Background Art

[0002] An all-vanadium redox flow battery (abbreviated as vanadium battery, VRB) is a new type of high-efficiency and large-capacity energy storage battery with a long service life and high safety. It has been successfully demonstrated and applied to the smooth output of wind farms. In the future, in the broad new energy fields, such as wind power generation, photovoltaic power generation, smart grids, etc., it has broad application prospects. In the production of electrolytes for all-vanadium redox flow batteries, the electrolytic stack is a carrier device for the electrolyte to circulate inside the battery. It plays a role in sealing and regulating the flow mode of the electrolyte inside the battery body, and has an important impact on the charging performance of the electrolyte.

[0003] In the actual application of all-vanadium redox flow batteries, during the charge and discharge process of the battery, side reactions such as hydrogen evolution and oxygen evolution will occur simultaneously at the positive and negative electrodes, which will lead to the imbalance of the valence state and concentration of the electrolyte, resulting in continuous attenuation of the battery capacity and seriously affecting the normal operation of the energy storage system. The valence state adjustment of all-vanadium redox flow batteries is achieved by changing the concentration ratio of vanadium ions in different valence states in the electrolyte. Specifically, the valence state adjustment of vanadium battery electrolytes is achieved by changing the concentration ratios of V2+ / V3+ and V4+ / V5+ in the electrolyte, so that the concentration ratios of these valence state ions remain unchanged during the charge and discharge process of the battery, thereby maintaining the stability of the battery performance.

[0004] Chinese Utility Model Patent No. 202120296345.1 discloses a movable vanadium electrolyte production system, which includes a box body, a crude electrolyte preparation area and a refined electrolyte preparation area; the crude electrolyte preparation area is arranged inside the box body and includes an automatic feeding system and a reaction kettle; the automatic feeding system supplies materials to the reaction kettle; the refined electrolyte preparation area is arranged inside the box body and includes a cathode liquid storage tank, a cathode pump, an anode liquid storage tank, an anode pump and an electrolysis device; the cathode liquid storage tank receives the crude electrolyte prepared in the reaction kettle, and the refined electrolyte preparation area forms a cathode liquid circulation loop and an anode liquid circulation loop. The system can realize on-site production of vanadium electrolyte at the place of use, with high integration degree, high degree of automatic control and small floor space.

[0005] There is a layering problem caused by the difference in ion concentration in the cathode liquid storage tank and the anode liquid storage tank. Different valence states of vanadium ions (such as V 2 +, V 3 +, V 4 +, V 5(+) Their stability in solution is different, and self-discharge reactions may occur during standing, resulting in concentration changes. Temperature changes also affect the ion diffusion rate. High temperatures may promote uniformity, while low temperatures may increase viscosity, making mixing difficult. When in the charged state, the positive electrolyte contains more V 5 +, and the negative electrode contains more V 2 +. There may be different ion distribution situations. The diffusion coefficients of ions with different valence states are different, which may all lead to local concentration differences. Improving the concentration balance in the production of electrolytes helps to improve the energy storage and discharge efficiency of the system. Currently, there is little relevant research. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for adjusting the concentration balance in the production of vanadium redox flow battery electrolytes, overcoming the deficiencies of the prior art. It adopts a containerized modular structure, and through the matching of the number of containers, the valence state adjustment of the electrolytes for vanadium redox flow battery energy storage systems with multiple power specifications can be quickly realized, reducing the problem of too long time-consuming caused by supporting design; optimizing the structure of the electrolytic stack, thinning the thickness of the bipolar current collector plate, and increasing the electrolyte density per unit volume; being able to quickly switch the series or parallel relationship of two electrolytic stacks as needed to quickly increase the electrolyte concentration; reducing the local concentration difference in the cathode liquid storage tank and the anode liquid storage tank, and improving the energy storage and discharge efficiency of the system.

[0007] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0008] A method for adjusting the concentration balance in the production of vanadium redox flow battery electrolytes, including a cathode liquid storage tank, a cathode pump, an anode liquid storage tank, an anode pump, and a header-type electrolysis device. The header-type electrolysis device includes a container, a cooling fan, an electrolysis stack, and an electrolysis power supply. Two groups of electrolysis stacks are arranged side by side in the container, and the two groups of electrolysis stacks are connected to the electrolysis power supply through cables. Windows are provided at the top of the container corresponding to the positions of the two groups of electrolysis stacks, and covers are provided on the windows; two groups of double-leaf doors are provided on one side of the container, and locks are provided on the double-leaf doors; an inlet and outlet pipe connection seat is provided at the rear side of the container; ventilation openings are provided on the left and right sides of the container, and cooling fans are installed inside the ventilation openings. A power supply terminal block is provided on the box board on the left or right side of the container; the electrolysis stack includes end clamping plates and membrane reaction units. Multiple groups of membrane reaction units are stacked and arranged between two end clamping plates and are fixedly connected by multiple groups of bolts. The membrane reaction unit includes a bidirectional current collecting electrode plate, an anode plate, a cathode plate, and a separator. Each of the two side surfaces of the bidirectional current collecting electrode plate is provided with an electrode area for placing electrodes, and a liquid flow hole is provided at each of the four corners of the plate body. A diversion groove is provided in the electrode area. An anode plate is provided on one side of the bidirectional current collecting electrode plate, and a cathode plate is provided on the other side. A separator is provided outside the anode plate and / or outside the cathode plate. A gasket is provided between the bidirectional current collecting electrode plate and the separator; a pressure balance hole is provided in the center of the electrode area of the bidirectional current collecting electrode plate, a pressure-bearing platform is provided around the pressure balance hole, and an annular sealing groove is provided on the pressure-bearing platform; liquid flow guiding platforms are respectively provided on the liquid flow holes, and the two liquid flow guiding platforms at the diagonal positions on the same side surface have the same structure. A through hole is provided on the side of the liquid flow guiding platform, and the through hole is communicated with the guide groove in the electrode area. A ring groove is provided on the surface of the liquid flow guiding platform; at least two of the anode liquid inlet pipe, anode liquid outlet pipe, cathode liquid inlet pipe, and cathode liquid outlet pipe are provided at the position corresponding to the liquid flow hole on one end clamping plate; the anode liquid inlet pipes of the two groups of electrolysis stacks are all connected to the anode pump, the anode liquid outlet pipes are all connected to the anode liquid storage tank, the cathode liquid inlet pipes are all connected to the cathode pump, and the cathode liquid outlet pipes are all connected to the cathode liquid storage tank. Among them, the anode liquid outlet pipe of the first group of electrolysis stacks is connected to the anode liquid inlet pipe of the second group of electrolysis stacks through an anode process switching pipe, and a pneumatic three-way ball valve is provided at the pipeline cross-connection; the cathode liquid outlet pipe of the first group of electrolysis stacks is connected to the cathode liquid inlet pipe of the second group of electrolysis stacks through a cathode process switching pipe, and a pneumatic three-way ball valve is also provided at the pipeline cross-connection; hydraulic stirrers are respectively provided in the cathode liquid storage tank and the anode liquid storage tank. The hydraulic stirrer includes an annular pipe and hydraulic nozzles evenly distributed on the annular pipe. The outlet of at least one hydraulic nozzle is upward, and the outlet of the hydraulic nozzle on the annular pipe opposite to it is downward. At least one hydraulic nozzle is in the horizontal direction of clockwise or counterclockwise, forming circulating liquid flows in both horizontal and vertical directions in the cathode liquid storage tank and the anode liquid storage tank at the same time. The hydraulic nozzle is a Venturi mixing nozzle.

[0009] Further, both the anode plate and the cathode plate are carbon felt or graphite felt.

[0010] Further, the separator is a perfluorosulfonic acid type ion exchange membrane of DuPont Company.

[0011] Further, an anolyte inlet pipe, an anolyte outlet pipe, a catholyte inlet pipe, and a catholyte outlet pipe are simultaneously provided on one of the end clamping plates.

[0012] Further, the diversion groove includes two mutually parallel main guide grooves and branch guide grooves connecting the two main guide grooves; two sealing groove bands are provided on the periphery of the bipolar current collecting electrode plate outside the liquid flow holes; the sealing grooves on the pressure bearing platform, the sealing groove bands on the plate surface, and the annular grooves on the surface of the liquid flow guiding platform are all correspondingly located on both sides of the bipolar current collecting electrode plate.

[0013] Further, openings are respectively provided on the separator at positions corresponding to the liquid flow holes and the pressure balance holes.

[0014] Further, lifting rings are respectively provided at the four corners of the top of the container; a filter screen is provided on the ventilation opening.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] 1) By adopting a containerized modular structure, the electrolyte valence state adjustment bypass matching operation of the all-vanadium redox flow battery energy storage system with multiple power specifications can be quickly realized by matching the number of containers, solving the common problem in the industry of too long time-consuming caused by conventional matching design, and improving the competitiveness of the redox flow battery market;

[0017] 2) Optimize the electrolytic cell stack structure, greatly reduce the thickness of the bipolar current collecting electrode plate, effectively reduce the size after plate stacking, so as to obtain a larger current density under the same cell stack volume, and improve the efficiency of all-vanadium redox flow battery electrolyte production;

[0018] 3) The two groups of electrolytic cell stacks can be quickly switched into a series or parallel relationship according to the needs of different stages of energy storage, so as to achieve the purpose of quickly increasing the electrolyte concentration;

[0019] 4) It can effectively reduce the difference problem of local ion concentration in the catholyte storage tank and the anolyte storage tank, improve the concentration balance of vanadium ions in electrolyte production, and further improve the energy storage and discharge efficiency of the production system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic process flow diagram of an embodiment of the present invention, only showing the anode circuit, and the cathode circuit is not shown;

[0021] Figure 2 It is a schematic internal structure diagram of the container in the embodiment of the present invention, with the right group of double doors hidden;

[0022] Figure 3 is a three-dimensional external schematic diagram of the electrolysis stack in the embodiment of the present invention;

[0023] Figure 4 is a schematic structural diagram of the electrolysis stack in the embodiment of the present invention;

[0024] Figure 5 is a schematic explosion structure diagram of the membrane reaction unit in the embodiment of the present invention;

[0025] Figure 6 is a schematic structural diagram of the bi-directional current collecting electrode plate in the embodiment of the present invention;

[0026] Figure 7 is Figure 6 a sectional view along line A-A in

[0027] Figure 8 is a schematic structural diagram of the hydraulic stirrer in the embodiment of the present invention;

[0028] In the figure: 1 - container, 2 - cooling fan, 3 - electrolysis stack, 4 - electrolysis power supply, 5 - cover plate, 6 - double-leaf door, 7 - ventilation opening, 8 - power connection socket, 9 - lifting ring, 10 - gasket, 11 - bi-directional current collecting electrode plate, 12 - anode plate, 13 - cathode plate, 14 - diaphragm, 15 - liquid flow hole, 16 - pressure balance hole, 17 - main guide groove, 18 - sub-guide groove, 19 - sealing groove belt, 20 - pressure-bearing platform, 21 - sealing groove, 22 - liquid flow guiding platform, 23 - through hole, 24 - annular groove, 25 - end clamping plate, 26 - membrane reaction unit, 27 - bolt, 28 - anode liquid inlet pipe, 29 - anode liquid outlet pipe, 30 - cathode liquid inlet pipe, 31 - cathode liquid outlet pipe, 32 - inlet and outlet pipe connection socket, 33 - cathode liquid storage tank, 34 - cathode pump, 35 - anode liquid storage tank, 36 - anode pump, 37 - header type electrolysis device, 38 - anode process switching pipe, 39 - pneumatic three-way ball valve, 40 - hydraulic stirrer, 41 - annular pipe, 42 - hydraulic spray head. Detailed Embodiments

[0029] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention.

[0030] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the specific embodiments required for use in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the specific embodiments described below are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other specific embodiments can also be obtained based on these specific embodiments.

[0031] The components of the embodiments of the present invention that are typically described and shown in detail in the specific embodiments herein can be arranged and designed in countless different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the specific embodiments is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0032] See Figure 1-2 、 Figure 8 , which is a schematic process flow diagram of a method for adjusting the concentration balance in the production of an electrolyte for a vanadium redox flow battery of the present invention, including a cathode liquid storage tank 33, a cathode pump 34, an anode liquid storage tank 35, an anode pump 36, and a header-type electrolysis device 37. The header-type electrolysis device 37 is connected to the anode pump 36 and the anode liquid storage tank 35 through an anode pipeline, and the header-type electrolysis device 37 is connected to the cathode pump 34 and the cathode liquid storage tank 33 through a cathode pipeline, constituting a full vanadium flow energy storage system for building an energy storage peak shaving power station and connecting to the grid for power generation. Hydraulic stirrers 40 are respectively provided in the cathode liquid storage tank 33 and the anode liquid storage tank 35.

[0033] The hydraulic stirrer 40 includes an annular pipe 41 and hydraulic nozzles 42 evenly distributed on the annular pipe. The outlet of at least one hydraulic nozzle faces upward, and the outlet of at least one hydraulic nozzle on the annular pipe opposite thereto faces downward. At least one hydraulic nozzle is in the horizontal direction of clockwise or counterclockwise, so that the liquid in the cathode liquid storage tank 33 and the anode liquid storage tank 35 simultaneously forms circulating liquid flows in two directions, horizontal and vertical. The hydraulic nozzle 42 adopts a Venturi mixing nozzle, which, by virtue of the Venturi effect, can form water flow circulation in two directions and can also enhance the stirring effect around the nozzle. The dynamic flow caused by the hydraulic nozzle 42 can effectively mix the electrolyte, reduce the concentration gradient, and maintain the relative uniformity of the ion distribution.

[0034] The header-type electrolysis device includes a container 1, a cooling fan 2, an electrolysis stack 3, and an electrolysis power supply 4. Two groups of electrolysis stacks 3 are arranged side by side in the container 1. The two groups of electrolysis stacks 3 are connected to the electrolysis power supply 4 through cables. Windows are respectively provided at the top of the container 1 corresponding to the positions of the two groups of electrolysis stacks 3, and covers 5 are provided on the windows. As needed, the electrolysis stack 3 can be taken out from the top window of the container 1 to improve the maintenance efficiency; two groups of double-leaf doors 6 are provided on one side of the container 1, and locks are provided on the double-leaf doors 6. When the production system is working, the double-leaf doors 6 are closed to reduce the internal pollution of the box body; an inlet and outlet pipe connection seat 32 is provided at the rear side of the container 1; ventilation openings 7 are respectively provided on the left and right sides of the container 1, and cooling fans 2 are installed inside the ventilation openings. A power supply connection seat 8 is provided on the box board on the left or right side of the container 1; the pipelines of the two groups of electrolysis stacks 3 are in a parallel relationship, and their anode liquid inlet and outlet pipes are correspondingly connected, and their cathode liquid inlet and outlet pipes are correspondingly connected. Lifting rings 9 are respectively provided at the four corners of the top of the container 1; filter nets are provided on the ventilation openings 7 for filtering dust in the air.

[0035] The anolyte inlet pipes of the two groups of electrolytic cell stacks are both connected to the anolyte pumps 36, the anolyte outlet pipes are both connected to the anolyte storage tank 35, the catholyte inlet pipes are both connected to the catholyte pumps 34, and the catholyte outlet pipes are both connected to the catholyte storage tank 33. Among them, the anolyte outlet pipe 29 of the first group of electrolytic cell stacks is connected to the anolyte inlet pipe 28' of the second group of electrolytic cell stacks through the anodic process switching pipe 38, and a pneumatic three-way ball valve 39 is provided at the pipe intersection. The pneumatic three-way ball valve 39 is a T-shaped three-way ball valve, which can realize the switching between series and parallel connections of the two groups of electrolytic cell stacks. Similarly, the catholyte outlet pipe of the first group of electrolytic cell stacks is connected to the catholyte inlet pipe of the second group of electrolytic cell stacks through the cathodic process switching pipe, and a pneumatic three-way ball valve is also provided at the pipe intersection. The control method is the same as that of the anodic circuit and will not be elaborated here.

[0036] When the two groups of electrolytic cell stacks work in parallel, the anolyte pumps 36 supply electrolyte to the anodic circuits of the two groups of electrolytic cell stacks at the same time, and the electrolyzed anolyte returns to the anolyte storage tank 35. The same is true for the catholyte. When the two groups of electrolytic cell stacks work in series, the anolyte pumps 36 only supply electrolyte to the anodic circuit of the first group of electrolytic cell stacks. The electrolyzed anolyte enters the anolyte inlet pipe 28' of the second group of electrolytic cell stacks through the anodic process switching pipe 38, and the anolyte processed by the second group of electrolytic cell stacks returns to the anolyte storage tank 35. The same is true for the catholyte. Generally, the electrolysis efficiency of the first group of electrolytic cell stacks is about 75%. The series structure can obtain electrolyte with a deeper electrolysis degree, and the electrolysis efficiency can reach more than 90%. In the later stage of energy storage, the series structure helps to quickly increase the electrolyte concentration.

[0037] See Figure 3 As shown in, the electrolytic cell stack 3 includes end clamping plates 25 and membrane reaction units 26. Multiple groups of membrane reaction units 26 are stacked and arranged between the two end clamping plates 25 and are connected and fixed into a whole through multiple groups of bolts 27. The anolyte inlet pipe 28, the anolyte outlet pipe 29, the catholyte inlet pipe 30, and the catholyte outlet pipe 31 are all located on the same end clamping plate 25. The anolyte inlet pipe 28 and the catholyte inlet pipe 30 both enter from the lower part, and the anolyte outlet pipe 29 and the catholyte outlet pipe 31 exit from the upper part, which can expel the air in the flow channel to the greatest extent and improve the uniformity of the electrolysis reaction.

[0038] See Figures 4-7, the membrane reaction unit includes a bidirectional current collecting electrode plate 11, an anode plate 12, a cathode plate 13 and a diaphragm 14. An anode plate 12 is provided on one side of the bidirectional current collecting electrode plate 11, and a cathode plate 13 is provided on the other side. Diaphragms 14 are respectively provided on the outer sides of the anode plate 12 and the cathode plate 13, and a gasket 10 is provided between the bidirectional current collecting electrode plate 11 and the diaphragm 14; each of the two side surfaces of the bidirectional current collecting electrode plate 11 is provided with an electrode area for placing electrodes, and a liquid flow hole 15 is provided at each of the four corners of the plate body. Liquid flow guiding platforms 22 are respectively provided on the liquid flow holes 15. The two liquid flow guiding platforms 22 at the diagonal positions on the same side surface have the same structure and are symmetrically arranged. A through hole 23 is provided on the side of the liquid flow guiding platform, and the through hole 23 communicates with the total guiding groove 17 in the electrode area. A ring groove 24 is provided on the surface of the liquid flow guiding platform 22. A diversion groove is provided in the electrode area, and the diversion groove includes two mutually parallel total guiding grooves 17 and a sub-guiding groove 18 connecting the two total guiding grooves 17. Two sealing groove bands 19 are provided on the surface of the plate body outside the liquid flow hole 15.

[0039] A pressure balance hole 16 is centrally provided in the electrode area of the bidirectional current collecting electrode plate 11. A pressure bearing platform 20 is provided around the pressure balance hole 16, and an annular sealing groove 21 is provided on the pressure bearing platform 20. The sealing groove 21 on the pressure bearing platform 20, the sealing groove band 19 on the surface of the plate body and the ring groove 24 on the surface of the liquid flow guiding platform are all correspondingly located on both sides of the bidirectional current collecting electrode plate 11. After multiple groups of membrane reaction units are stacked in sequence, both ends are closed by end clamping plates and connected by long bolts to form an electrolytic stack in the production of a vanadium redox flow battery or its electrolyte. After the long bolts are tightened, the gasket 10 is compressed and deformed to fill the sealing groove band 19, the sealing groove 21 and the ring groove 24, thereby achieving sealing. A bolt is also installed in the pressure balance hole 16 to balance the deformation caused by the tightening force of other bolts, so that the overall structure of the stack device is kept stable. The balanced clamping effect is beneficial to improving the uniformity of the liquid flow in the membrane reaction unit and reducing internal leakage. The present invention uses the pressure balance hole 16 to make the clamping pressure of the bidirectional current collecting electrode plate 11 more evenly dispersed after stacking, so that the bidirectional current collecting electrode plate 11 can be thinned to the greatest extent, thereby effectively reducing the size after the plate sheets are stacked, achieving a larger current density under the same stack volume, and further improving the efficiency of the production of the vanadium redox flow battery electrolyte.

[0040] Both the anode plate 12 and the cathode plate 13 are carbon felt or graphite felt. These materials have good electrical conductivity and chemical stability and can withstand the chemical reactions generated during the charge and discharge process of the battery. The porous structure of the carbon felt and graphite felt is beneficial to the penetration of the electrolyte and the diffusion of ions, thereby improving the energy conversion efficiency of the battery. In addition, these materials also have a relatively high specific surface area, providing more active sites for the electrochemical reaction.

[0041] The diaphragm 14 is a perfluorosulfonic acid type ion exchange membrane of DuPont Company. This is a strong acid type ion exchange membrane with good hydrophilicity. The membrane has a high water content and a low membrane resistance. Since the concentration of fixed ions in the membrane is low, the repulsive force to hydroxide ions is small, and in an acidic solution, it has good chemical stability during electrolysis. The Nafion membrane is its representative product.

[0042] Openings are respectively provided in the diaphragm 14 at positions corresponding to the liquid flow holes 15 and the pressure balance holes 16, without affecting the sealing when adjacent membrane reaction units are connected.

[0043] In the embodiment, at least two of the anolyte inlet pipe 28, the anolyte outlet pipe 29, the catholyte inlet pipe 30, and the catholyte outlet pipe 31 may be provided at positions corresponding to the liquid flow holes 15 on one end clamp 25, as long as the anolyte and the catholyte can flow under the minimum liquid resistance.

[0044] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for adjusting the concentration balance in the production of vanadium flow battery electrolyte, comprising a cathode liquid storage tank, a cathode pump, an anode liquid storage tank, an anode pump and a header type electrolysis device, characterized in that: The container-type electrolysis device includes a container, a cooling fan, an electrolytic cell stack and an electrolytic power supply. Two groups of electrolytic cell stacks are arranged side by side in the container, and the two groups of electrolytic cell stacks are connected to the electrolytic power supply through cables. Windows are respectively provided at the top of the container corresponding to the positions of the two groups of electrolytic cell stacks, and covers are provided on the windows; two groups of double doors are provided on one side of the container, and locks are provided on the double doors; an inlet and outlet pipe connection seat is provided on the rear side of the container; ventilation holes are respectively provided on the left and right sides of the container, and cooling fans are installed on the inner sides of the ventilation holes, and a power terminal block is provided on the box plate on the left or right side of the container; the electrolytic cell stack includes end clamps and membrane reaction units, and multiple groups of membrane reaction units are stacked and arranged between the two end clamps and fixed by multiple groups of bolts. The membrane reaction unit includes a bidirectional current collecting electrode plate, an anode plate, a cathode plate and a diaphragm, and the two side surfaces of the bidirectional current collecting electrode plate are each provided with a The electrode region where the electrode is placed has a liquid flow hole at each of the four corners of the plate body, a flow guide groove is provided in the electrode region, an anode plate is provided on one side of the bidirectional current collecting electrode plate, and a cathode plate is provided on the other side, a diaphragm is provided on the outer side of the anode plate and / or the outer side of the cathode plate, and a sealing gasket is provided between the bidirectional current collecting electrode plate and the diaphragm; a pressure balance hole is provided in the center of the electrode region of the bidirectional current collecting electrode plate, a pressure bearing platform is provided around the pressure balance hole, and an annular sealing groove is provided on the pressure bearing platform; liquid flow guide platforms are respectively provided on the liquid flow holes, and the two liquid flow guide platforms at the diagonal positions of the same side surface have the same structure, a through hole is provided on the side of the liquid flow guide platform, and the through hole is connected to the guide groove in the electrode region, and an annular groove is provided on the surface of the liquid flow guide platform; at least two of the anode liquid inlet pipe, the anode liquid outlet pipe, the cathode liquid inlet pipe, and the cathode liquid outlet pipe are provided at the position corresponding to the liquid flow hole on the one end clamping plate; The anode liquid inlet pipes of the two groups of electrolytic stacks are connected to the anode pump, the anode liquid outlet pipes are connected to the anode liquid storage tank, the cathode liquid inlet pipes are connected to the cathode pump, and the cathode liquid outlet pipes are connected to the cathode liquid storage tank, wherein the anode liquid outlet pipe of the first group of electrolytic stacks is connected to the anode liquid inlet pipe of the second group of electrolytic stacks through the anode process switching pipe, and a pneumatic three-way ball valve is provided at the cross-connection of the pipes; the cathode liquid outlet pipe of the first group of electrolytic stacks is connected to the cathode liquid inlet pipe of the second group of electrolytic stacks through the cathode process switching pipe, and the pipes are cross-connected. A pneumatic three-way ball valve is also provided at the connection; a hydraulic agitator is respectively provided in the cathode liquid storage tank and the anode liquid storage tank, and the hydraulic agitator comprises an annular tube and hydraulic nozzles evenly distributed on the annular tube, wherein the outlet of at least one hydraulic nozzle is upward, and the outlet of the hydraulic nozzle on the annular tube opposite thereto is downward, and at least one hydraulic nozzle is in a clockwise or counterclockwise horizontal direction, so that circulating liquid flows in both horizontal and vertical directions are formed in the cathode liquid storage tank and the anode liquid storage tank at the same time, and the hydraulic nozzles are Venturi mixed flow nozzles.

2. The method for adjusting the concentration balance in the production of vanadium flow battery electrolyte according to claim 1, characterized in that: The anode plate and the cathode plate are both carbon felt or graphite felt.

3. The method for adjusting the concentration balance in the production of vanadium flow battery electrolyte according to claim 1, characterized in that: The diaphragm is a perfluorosulfonic acid ion exchange membrane produced by DuPont.

4. The method for adjusting the concentration balance in the production of vanadium flow battery electrolyte according to claim 1, characterized in that: An end clamping plate is provided with an anode liquid inlet pipe, an anode liquid outlet pipe, a cathode liquid inlet pipe and a cathode liquid outlet pipe.

5. The method for adjusting the concentration balance in the production of vanadium flow battery electrolyte according to claim 1, characterized in that: The guide groove includes two mutually parallel main guide grooves and a branch guide groove connecting the two main guide grooves; two circles of sealing groove belts are arranged around the bidirectional current collecting electrode plate outside the liquid flow hole; the sealing groove on the pressure platform, the sealing groove belt on the surface of the plate body and the annular groove on the surface of the liquid flow guide platform are all correspondingly located on both sides of the bidirectional current collecting electrode plate.

6. The method for adjusting concentration balance in the production of vanadium flow battery electrolyte according to claim 1, characterized in that: The diaphragm is provided with openings at positions corresponding to the liquid flow holes and the pressure balance holes.

7. The method for adjusting concentration balance in the production of vanadium flow battery electrolyte according to claim 1, characterized in that: The top four corners of the container are respectively provided with lifting rings; There is a filter on the vent.

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