A redox system for a flow battery

Abstract

The present invention discloses a reduction system for a flow battery, which relates to the technical field of flow battery reduction systems. The system includes a reduction liquid tank for storing reduction liquid, a pump, a reduction liquid outlet pipe, a reduction liquid return pipe, a flow battery stack, and a power supply. The flow battery stack, the reduction liquid outlet pipe, the reduction liquid tank, and the reduction liquid return pipe are connected in sequence, and the reduction liquid return pipe is connected to the flow battery stack to form a closed loop. An inlet pipe and an outlet pipe are respectively connected to both sides of the flow battery stack. The pump is arranged on the reduction liquid outlet pipe. The power supply is connected to the flow battery stack and is used to provide an adjustable direct current for the flow battery stack. By setting up a closed loop formed by connecting the flow battery stack, the reduction liquid outlet pipe, the reduction liquid tank, and the reduction liquid return pipe in sequence, the present invention can conveniently and quickly restore the activity of the electrolyte, thereby restoring the capacity of the battery. The reduction method is relatively simple, reducing the working time, improving the working efficiency, and reducing the maintenance cost.

Description

Technical Field

[0001] The present invention relates to the technical field of redox flow battery reduction systems, and particularly to a redox flow battery reduction system. Background Art

[0002] In the field of redox flow batteries, due to the uniqueness of chemical energy storage, during the construction and operation of the energy storage system, the chemical stock solution more or less comes into contact with air and undergoes an oxidation reaction, and affected by trace impurities in the electrolyte, the chemical properties of some electrolytes are changed, resulting in a decrease in battery capacity. A redox flow battery reduction system is a system that restores the activity of the electrolyte through a reduction reaction, thereby restoring the battery capacity, and it has a wide range of applications.

[0003] In the prior art, the Chinese invention patent with the application number CN202211332184.2 discloses a vanadium redox flow battery electrolyte reduction system and a capacity recovery method, aiming to solve the technical problem that the existing electrolyte capacity recovery method will introduce impurities and cause an increase in electrode resistance. Its technical solution is as follows: reacting zinc salt and imidazole ligand with a mass twice that of the zinc salt in a reaction kettle for 12 hours to obtain a carbon-coated transition metal material catalyst Co2NiC, putting the catalyst into the positive electrode storage tank for reaction, introducing inert gas and hydrogen, so that the valence state of the electrolyte after the reaction is 3.503. Due to the special structural properties of the catalyst, it will not overflow into the electrolyte, effectively reducing the pentavalent vanadium ions, without introducing new impurity ions, and will not affect the capacity and efficiency due to impurity ions. The reaction process is controllable, and the valence state of the electrolyte after the reaction is 3.503, and the capacity recovery effect reaches 99.9%. The method for reducing V5+ in this invention is relatively complex. Therefore, there is an urgent need to provide a convenient and simple redox flow battery reduction system. Summary of the Invention

[0004] In order to solve the problems existing in the above background art, the present invention provides a redox flow battery reduction system.

[0005] The present invention is realized through the following technical solutions:

[0006] A redox flow battery reduction system includes a reduction liquid tank for storing reduction liquid, a pump, a reduction liquid outlet pipe, a reduction liquid return pipe, a redox flow battery stack, and a power supply; the redox flow battery stack, the reduction liquid outlet pipe, the reduction liquid tank, and the reduction liquid return pipe are connected in sequence, and the reduction liquid return pipe is connected to the redox flow battery stack to form a closed loop; an inlet pipe and an outlet pipe are respectively connected to both sides of the redox flow battery stack; the pump is arranged on the reduction liquid outlet pipe; the power supply is connected to the redox flow battery stack for providing an adjustable direct current to the redox flow battery stack.

[0007] Preferably, the reduction liquid tank is provided with reduction liquid.

[0008] Preferably, the flow battery stack further includes a positive electrolyte tank and a negative electrolyte tank.

[0009] Preferably, both the liquid outlet pipe and the liquid inlet pipe are connected to the liquid outlet of the negative electrolyte tank; or, both the liquid outlet pipe and the liquid inlet pipe are connected to the liquid outlet of the positive electrolyte tank.

[0010] Preferably, the reducing solution includes divalent iron ions.

[0011] Preferably, the pump is a liquid extraction pump for driving the reducing solution to enter the flow battery stack from the reducing solution outlet pipe.

[0012] Preferably, electrolytes are provided in both the positive electrolyte tank and the negative electrolyte tank.

[0013] Preferably, the electrolyte includes trivalent iron ions.

[0014] Preferably, the power supply is electrically connected to the flow battery stack.

[0015] Preferably, the power supply is a DC power supply.

[0016] Compared with the prior art, the advantages of the present invention are as follows:

[0017] By providing a closed loop formed by sequentially connecting a flow battery stack, a reducing solution outlet pipe, a reducing solution tank, and a reducing solution return pipe, the present invention can conveniently and quickly restore the activity of the electrolyte, thereby restoring the activity of the electrolyte, and has the characteristics of simple operation and high reliability.

[0018] In the present invention, the reducing solution tank stores the reducing solution. During system operation, after the pump operates, the reducing solution enters the flow battery stack through the reducing solution outlet pipe and then returns to the reducing solution tank through the reducing solution return pipe. Both the liquid outlet pipe and the liquid inlet pipe are connected to the liquid outlet of the negative electrolyte tank; or, both the liquid outlet pipe and the liquid inlet pipe are connected to the liquid outlet of the positive electrolyte tank, enter the flow battery stack through the liquid inlet pipe, and then flow out through the liquid outlet pipe. The DC power supply provides an adjustable direct current to the flow battery stack. The reducing solution and the electrolyte undergo an oxidation-reduction reaction inside the flow battery stack, the Fe2+ in the reducing solution is oxidized to Fe3+, and the Fe3+ in the liquid tank is reduced to Fe2+, thereby restoring the activity of the electrolyte and further restoring the battery capacity.

[0019] The reduction method of the present invention is relatively simple, with simple steps, convenient operation, easy to use, easy for workers to master, reducing working time, improving work efficiency, and reducing maintenance costs. Description of the Drawings

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0021] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention.

[0022] In the figure: 1, reducing solution tank; 2, pump; 3, reducing solution outlet pipe; 4, reducing solution return pipe; 5, flow battery stack; 6, inlet pipe; 7, outlet pipe; 8, power supply. Detailed Embodiments

[0023] The following will describe in detail the embodiments of the present invention, and the examples of the embodiments are shown in the drawings. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention.

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0025] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0026] In the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or communication with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] See Figure 1 Figure 1 , which is an embodiment of a reduction system for a flow battery according to the present invention. In this embodiment, it includes a reducing solution tank 1 for storing the reducing solution, a pump 2, a reducing solution outlet pipe 3, a reducing solution return pipe 4, a flow battery stack 5, and a power supply 8; the flow battery stack 5, the reducing solution outlet pipe 3, the reducing solution tank 1, and the reducing solution return pipe 4 are connected in sequence, and the reducing solution return pipe 4 is connected to the flow battery stack 5 to form a closed loop; an inlet pipe 6 and an outlet pipe 7 are respectively connected to both sides of the flow battery stack 5; the pump 2 is provided on the reducing solution outlet pipe 3; the power supply 8 is connected to the flow battery stack 5 and is used to provide an adjustable direct current for the flow battery stack 5.

[0028] In this embodiment, the reducing solution tank 1 is provided with the reducing solution.

[0029] In this embodiment, the flow battery stack 5 further includes a positive electrolyte tank and a negative electrolyte tank.

[0030] In this embodiment, both the outlet pipe 6 and the inlet pipe 7 are connected to the outlet of the negative electrolyte tank; or, both the outlet pipe 6 and the inlet pipe 7 are connected to the outlet of the positive electrolyte tank.

[0031] In this embodiment, the reducing solution includes divalent iron ions.

[0032] In this embodiment, the pump 2 is a liquid extraction pump and is used to drive the reducing solution to enter the flow battery stack 5 from the reducing solution outlet pipe 3.

[0033] In this embodiment, both the positive electrolyte tank and the negative electrolyte tank are provided with electrolyte solutions.

[0034] In this embodiment, the electrolyte solution includes trivalent iron ions.

[0035] In this embodiment, the power supply 8 is electrically connected to the flow battery stack 5.

[0036] In this embodiment, the power supply 8 is a DC power supply.

[0037] The reducing solution tank 1 stores the reducing solution inside. When the system operates, after the pump 2 runs, the reducing solution enters the flow battery stack 5 through the reducing solution outlet pipe 3 and then returns to the reducing solution tank 1 through the reducing solution return pipe 4.

[0038] Both the outlet pipe 6 and the inlet pipe 7 are connected to the outlet of the negative electrolyte tank; or, both the outlet pipe 6 and the inlet pipe 7 are connected to the outlet of the positive electrolyte tank, and the reducing solution enters the flow battery stack 5 through the inlet pipe 6 and then flows out through the outlet pipe 7.

[0039] The DC power supply is used to provide an adjustable DC current for the flow battery stack 5. The reducing liquid and the electrolyte undergo an oxidation-reduction reaction inside the flow battery stack 5. Fe2+ in the reducing liquid is oxidized to Fe3+, and Fe3+ in the liquid tank is reduced to Fe2+.

[0040] By setting up a closed loop formed by connecting the flow battery stack 5, the reducing liquid outlet pipe 3, the reducing liquid tank 1, and the reducing liquid return pipe 4 in sequence, it is possible to conveniently and quickly restore the activity of the electrolyte, thereby restoring the battery capacity. The operation is simple and the reliability is high.

[0041] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0042] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A redox system for a flow battery, characterized in that, It includes a reducing solution tank (1) for storing a reducing solution containing divalent iron ions, a pump (2), a reducing solution outlet pipe (3), a reducing solution return pipe (4), a flow battery stack (5), and a power source (8); The flow battery stack (5) is sequentially connected to the reducing solution outlet pipe (3), the reducing solution tank (1), and the reducing solution return pipe (4), and the reducing solution return pipe (4) is connected to the flow battery stack (5) to form a closed loop; An inlet pipe (6) and an outlet pipe (7) are respectively connected to both sides of the flow battery stack (5), and both the outlet pipe (6) and the inlet pipe (7) are connected to the outlet of the negative electrode liquid tank; or, both the outlet pipe (6) and the inlet pipe (7) are connected to the outlet of the positive electrode liquid tank; The pump (2) is arranged on the reducing solution outlet pipe (3); The power source (8) is electrically connected to the flow battery stack (5) to provide an adjustable direct current for the flow battery stack (5), and the flow battery stack (5) is reused as a charge and discharge stack for the main battery during the rebalancing process. A reverse direct current is applied through the power source (8) to drive the oxidation-reduction reaction between Fe²⁺ in the reducing solution and Fe³⁺ in the electrolyte.

2. The redox flow battery reduction system according to claim 1, wherein The pump (2) is a liquid extraction pump for driving the reducing solution to enter the flow battery stack (5) from the reducing solution outlet pipe (3).

3. The redox flow battery reduction system according to claim 2, wherein Electrolyte is provided in both the positive electrode liquid tank and the negative electrode liquid tank.

4. The flow battery reduction system according to claim 3, characterized in that, The electrolyte includes trivalent iron ions.

5. The redox flow battery reduction system according to claim 1, characterized in that, The power source (8) is a DC power source.

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