An electrolyte component separation device

Abstract

This invention discloses an electrolyte component separation device, the technical solution of which includes an electrolyte storage tank, an inlet pipe, an outlet pipe, an exhaust pipe, a star-shaped water distributor for preventing electrolyte return, a piston distributor for separating the return and outlet zones within the tank, an H-type oil-impregnated rubber sealing ring for sealing the partitions, a liquid passage gate on the piston distributor for connecting / separating the return and outlet zones within the storage tank, and upper and lower limit posts of the distributor inside the tank for opening and closing the liquid passage gate. By isolating the system within the tank through the piston distributor to achieve partitioning of electrolyte outlet and return, a high-concentration electrolyte can be maintained to continuously carry out electrochemical reactions, thereby greatly eliminating or mitigating the battery concentration polarization problem exacerbated by the decrease in electrolyte concentration before and after the reaction in multi-stack series schemes of flow battery systems, and greatly improving the reaction efficiency and service life of flow battery systems.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to an electrolyte component separation device. Background Technology

[0002] 1. Flow batteries use an electrolyte solution as the energy storage medium and a fuel cell stack as the reaction site. During charging, a circulating pump drives the electrolyte solution to flow through the stack. During this flow, electrical energy is converted into chemical energy and stored in the electrolyte solution through redox reactions. The process is reversed during discharging. Zinc-iron flow batteries have advantages such as high reliability, low cost, high efficiency, and environmental friendliness, making them suitable for a wide range of applications.

[0003] 2. Concentration polarization: During electrochemical reactions, reactants react at the electrode surface, causing a gradual decrease in their concentration. However, the concentration of reactants in the electrolyte solution, farther from the electrode, remains relatively high. This concentration difference leads to charge accumulation on the electrode surface, creating a potential difference. As the reaction continues, if the reactants on the electrode surface cannot be replenished in time, this concentration difference will further increase, exacerbating concentration polarization. This not only affects battery efficiency but also limits battery performance. The impact of concentration polarization is particularly pronounced in high current density regions. If this phenomenon is not addressed, it will intensify concentration polarization, increasing battery resistance during charging, preventing the battery from reaching its set capacity, significantly reducing the reaction efficiency of the battery stack system, and severely impacting its lifespan.

[0004] In summary, this invention employs a piston-type water distributor device and a piston-type water distributor to achieve component separation of the electrolyte before and after the reaction in the storage tank. This greatly eliminates the concentration polarization phenomenon in the battery caused by the inconsistency in electrolyte concentration before and after the reaction, thereby improving the charge and discharge performance of the flow battery. This invention has a simple structure and is of great significance in improving reaction efficiency and extending service life. Summary of the Invention

[0005] This invention addresses the shortcomings and defects of existing technologies by providing an electrolyte component separation device, which can alleviate the concentration polarization problem in multi-tank flow battery systems caused by the decrease in electrolyte concentration before and after the reaction, thereby improving the reaction efficiency and service life of the flow battery system.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] An electrolyte component separation device includes: a tank 1, a return pipe 2, a drain pipe 3, a star-shaped water distributor 4, a piston distributor 5, a central shaft of the tank 6, a distributor upper limit top column 7, a distributor lower limit top column 8, and an exhaust pipe 9.

[0008] Tank 1 is equipped with a liquid storage tank. The top of the tank is equipped with a distributor upper limit column 7 and the bottom is equipped with a distributor lower limit column 8. The inside of tank 1 is equipped with a piston distributor 5, which moves up and down through the central axis 6 of the tank. The return pipe 2 is connected to the star-shaped water distributor 4, which can evenly distribute the inlet electrolyte and avoid the solution concentration being too concentrated.

[0009] The piston distributor 5 has a liquid return pipe 2 at the top. The electrolyte enters the star-shaped water distributor 4 through the liquid return pipe 2 and is evenly distributed in the upper area.

[0010] The piston distributor device 5 includes a piston distributor cylinder 5.1, an H-type or E-type oil-impregnated rubber sealing ring 5.2 installed around its edge, a piston distributor 5 cooperating with a central shaft 6 of the tank, and a bushing having an anti-rotation structure 5.3.

[0011] A fluid passage 5.4 is installed on the piston distributor cylinder 5.1, and a fluid passage door 5.5 is installed at the top with a central through-shaft. It is connected to the piston distributor cylinder 5.1 through a shaft hole to open and close. When the fluid passage door 5.5 is open, it can connect the upper and lower areas. The fluid passage door 5.5 has a sealing structure around its perimeter, which can effectively isolate the connection between the upper and lower areas when the fluid passage door 5.5 is closed.

[0012] The piston distributor cylinder 5.1 has a hollow structure and can float on the surface of the electrolyte. The cylinder has a liquid passage limiter 5.6. When the liquid passage door 5.5 is opened to a certain angle, the boss structure of the liquid passage limiter 5.6 (as shown in the enlarged figure) provides movement constraint, which can keep the piston distributor in the open or closed state when it is floating.

[0013] Tank 1 is equipped with a distributor upper limit top column 7 and a distributor lower limit top column 8 inside the liquid storage tank.

[0014] The outlet pipe 3 inside the storage tank is located below the lowest point of the piston distributor 5 within the tank. When the piston distributor's liquid inlet valve 5.5 is closed, due to the influence of the circulating pump, there is negative pressure in the lower zone of the piston distributor 5, and the piston distributor 5 descends as the electrolyte in the lower zone is discharged. When it descends to the height of the distributor's descent limit top column 8, the distributor's descent limit top column 8 opens the liquid inlet valve 5.5, and the piston distributor 5 rises. When the piston distributor 5 rises to the height of the distributor's ascending limit top column 7, the distributor's ascending limit top column 7 closes the liquid inlet valve 5.5.

[0015] Preferably, the water distributor is a star-shaped water distributor 4, which can evenly distribute the inlet electrolyte, avoid excessive concentration of electrolyte, and also avoid the impact of excessive concentration of inlet liquid forming a water column on the movement of piston distributor 5.

[0016] Preferably, the piston distributor 5 can move up and down inside the tank 1, and its overall density is less than that of water.

[0017] Preferably, when the liquid passage gate 5.5 on the piston distributor 5 is open, the piston distributor 5 can spontaneously float to the surface of the liquid; when the liquid passage gate 5.5 is closed, if the electrolyte pump is pumping liquid, i.e., draining liquid through the drain pipe 3, the piston distributor 5 can sink due to negative pressure.

[0018] Preferably, the system can isolate the unreacted electrolyte from the reacted electrolyte during the charging and discharging process of the flow battery, or when the water pump is circulating and simultaneously feeding and discharging the electrolyte.

[0019] The beneficial technical effects of this invention are: it can greatly eliminate the concentration polarization phenomenon in the battery caused by the inconsistency of electrolyte concentration before and after the reaction, thus improving the charge and discharge performance of the flow battery. The overall structure is simple and low-cost, and it can be modularly installed in the flow battery storage tank. This can alleviate the battery concentration polarization problem exacerbated by the decrease in electrolyte concentration before and after the reaction in multi-tank series flow battery schemes, thereby improving the reaction efficiency and service life of the flow battery system. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the electrochemical principle of the existing flow battery system of this invention.

[0021] Figure 2 This is a schematic diagram of the flow battery system framework of Example 1 of the present invention.

[0022] Figure 3 This is a schematic diagram of the overall structure of the present invention.

[0023] Figure 4 yes Figure 3 Schematic diagram of the piston-type distributor

[0024] Reference numerals: 1. Tank body; 2. Return pipe; 3. Drain pipe; 4. Star-shaped water distributor; 5. Piston distributor; 6. Central shaft of tank body; 7. Top column of distributor upper limit; 8. Top column of distributor lower limit; 9. Exhaust pipe; 10. Piston distributor cylinder body; 5.1. H-type oil-impregnated rubber sealing ring; 5.2. Anti-rotation structure; 5.3. Liquid passage; 5.4. Liquid passage valve; 5.5. Liquid passage valve limiter; 5.6. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining this invention, and the embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this invention, and should not be construed as limiting this invention.

[0026] Example 1.

[0027] like Figure 1The diagram illustrates the reaction principle of a zinc-iron flow battery. During charging, an oxidation reaction occurs at the positive electrode, where Fe2+ reacts to form Fe3+, while a reduction reaction occurs at the negative electrode, where Zn2+ is reduced to elemental Zn and deposited in the battery stack. During discharging, Fe3+ at the positive electrode is converted to Fe2+, and elemental Zn in the battery stack is converted to Zn2+ and flows back to the negative electrode storage tank.

[0028] Existing flow batteries are produced on a large scale, such as Figure 2 Taking a zinc-iron battery as an example, the electrolyte solution is stored in positive and negative electrode storage tanks. It is supplied to the main pipelines of the positive and negative electrodes via positive and negative electrode circulation pumps. The main pipelines then supply the electrolyte evenly and continuously to a battery stack system composed of multiple stacks through branch pipelines. Electrochemical reactions occur in the positive and negative electrode solutions within the stack. For example, in the positive electrode reaction, Fe is generated after the reaction. 2+ The solution is transferred back to the positive electrode storage tank via the positive electrode circulation pump, which reduces the Fe content in the positive electrode storage tank. 3+ The concentration of Zn in the negative electrode reaction... 2+ The Zn continuously reacts to form Zn in the negative electrode storage tank. 2+ If the concentration continues to decrease, this phenomenon will exacerbate concentration polarization if not addressed, which will increase the resistance of the battery during charging, making it unable to reach the set capacity, resulting in the battery not being fully charged and seriously affecting battery life.

[0029] like Figure 2 The image shows a flow battery system that uses an electrolyte concentration mixing and separation device, specifically including a flow battery liquid supply system and an electrolyte component mixing and separation device.

[0030] The flow battery system is as follows: the negative electrode electrolyte flows out from the drain pipe of the negative electrode storage tank through the negative electrode circulation pump, flows through the stack system and the negative electrode electrolyte return pipe in sequence, and finally flows back to the negative electrode electrolyte storage tank; the positive electrode electrolyte flows out from the drain pipe of the positive electrode storage tank under the action of the positive electrode circulation pump, flows to the stack system and undergoes an electrochemical reaction with the negative electrode electrolyte, and the positive electrode electrolyte after the reaction flows back to the positive electrode storage tank through the return pipe.

[0031] For details of the structure of the electrolyte component separation device, please refer to [link / reference]. Figure 3 and Figure 4 Specifically, it includes: an electrolyte storage tank body 1, a return pipe 2, a drain pipe 3, a central shaft 6, a star-shaped water distributor 4 for uniformly distributing the electrolyte return after reaction, a piston distributor 5 for separating the return and outlet areas within the storage tank, an H-shaped sealing ring 5.2 for sealing the partition, a liquid passage valve 5.5 on the piston distributor 5 for connecting / separating the return and outlet areas within the storage tank, and a distributor upper limit pin 7 and a distributor lower limit pin 8 inside the tank body 1 for opening and closing the liquid passage valve.

[0032] The principle of the electrolyte concentration mixing and separation device applied in this example is as follows: Figure 2 When the circulating pump starts, the electrolyte reacts and circulates within the system. Taking the positive electrode storage tank during charging as an example, the electrolyte in tank 1 before the reaction is entirely Fe. 3+ As charging begins, the circulation pump starts, and the Fe in tank 1... 3+ The solution is discharged and enters the fuel cell stack system for reaction, while the liquid inlet valve 5.5 on the piston distributor 5 is closed. As the circulation pump operates, the piston distributor 5 moves downward under the negative pressure within the system; simultaneously, an electrochemical reaction occurs within the fuel cell stack system, Fe... 3+ A reduction reaction occurs, and the electron-gaining reaction is Fe. 2+ Fe in the electrolyte after the reaction 3+ Concentration reduced and doped with Fe 2+ The ion-forming return liquid enters the star-shaped water distributor 4 from the return pipe 2 above the tank 1, and after being evenly distributed, is transported back into the tank 1; at this time, the piston distributor 5, due to its H-type sealing ring 5.2, isolates the outlet zone from the return zone, and the low-concentration Fe in the return liquid... 3+ with Fe 2+ The ionic solution does not react with the high concentration of Fe in the outlet zone. 3+ The solution is mixed to ensure that the solution delivered to the fuel cell stack system by the circulating pump is always a high-concentration electrolyte; when the piston distributor 5 descends to the bottom of the tank 1, the high-concentration Fe in the outlet zone... 3+ The solution has been almost completely transported. At this point, the distributor descending limit pin 8 at the bottom of tank 1 passes through the liquid passage 5.4 in the piston distributor 5 and opens the liquid passage 5.5. The liquid passage 5.5 is opened and rotated to the fixed position of the liquid passage limit pin 5.6. The liquid outlet area and the liquid return area are mixed, and the solution concentration in tank 1 is uniform. The piston distributor 5 has a hollow structure and floats upward due to buoyancy. When it rises to the top of tank 1, the distributor ascending limit pin 7 in tank 1 closes the liquid passage 5.5. The piston distributor 5 then divides the electrolyte in the system into the liquid return area and the liquid outlet area again. This process continues while the circulation pump is working.

[0033] Therefore, during the charging and discharging of the battery stack, the system can ensure that a high concentration of electrolyte is continuously delivered to the battery stack for reaction, thereby improving the reaction efficiency and greatly reducing the concentration polarization phenomenon caused by concentration differences, thus achieving the purpose of improving the efficiency of the battery stack, the reaction efficiency of the flow battery system, and its service life.

[0034] The above embodiments are descriptions of specific implementations of the present invention, and not limitations thereof. Those skilled in the art can make various modifications and changes without departing from the spirit and scope of the present invention to obtain corresponding equivalent technical solutions. Therefore, all equivalent technical solutions should be included in the patent protection scope of the present invention.

Claims

1. An electrolyte component separation device, characterized by, The application relates to a liquid distribution device for a tank, which comprises a tank body, a liquid return pipe on the top of the tank body, an exhaust pipe, a star-shaped water distributor, a piston distributor, a tank central shaft, a piston distributor cylinder, a liquid passage, a liquid passage door, an upper limiting top column for the piston distributor and a lower limiting top column for the piston distributor.

2. An electrolyte component separation device according to claim 1, wherein, The piston distributor can divide the solution in the tank body by opening and closing the liquid passage door, and the opening and closing state of the liquid passage door can be controlled according to the liquid level in the tank body.

3. The electrolyte component separation apparatus of claim 1, wherein, The piston distributor and the H-shaped oil-containing rubber sealing ring on the piston distributor cylinder and the liquid passage door with the sealing structure.

4. The electrolyte component separation apparatus of claim 1, wherein, The piston distributor can move up and down along the tank central shaft, and the shaft sleeve has a rotation stopping structure to avoid the rotation of the piston water distributor in the tank.

5. The electrolyte component separation apparatus of claim 2, wherein, The piston distributor is provided with a liquid passage door limiter, which can constrain the movement of the liquid passage door after the liquid passage door is opened, and the liquid passage door is in a normally open state when the piston distributor rises.

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