Preparation method of zinc-bromine liquid flow battery bipolar plate and bipolar plate and zinc-bromine liquid flow battery

Abstract

The present application relates to a method for preparing a bipolar plate for a zinc-bromine flow battery, a bipolar plate and a zinc-bromine flow battery. The preparation method comprises the following steps: obtaining polyethylene, carbon black and graphite, mixing them in a preset ratio to obtain a mixed material; treating the mixed material by at least one of hot pressing or extrusion to prepare a carbon plastic sheet; obtaining activated carbon fiber, mixing the carbon plastic sheet with the carbon plastic sheet at a temperature of 160°C and a pressure of 20 kgf / cm 2 The bipolar plates are made by thermoplastic treatment. Activated carbon fibers are less likely to absorb excessive bromine, preventing the reaction of excess bromine with zinc on the negative plate to produce zinc and bromide ions, which can cause self-discharge during charging and reduce the impact on battery efficiency.

Description

Technical Field

[0001] The present application relates to the field of liquid flow batteries, and in particular to a method for preparing a zinc-bromine liquid flow battery bipolar plate, a bipolar plate, and a zinc-bromine liquid flow battery. Background Art

[0002] In order to achieve the "dual carbon" goals, the installed capacity of renewable energy power generation is increasing. However, due to the intermittent and volatile nature of renewable energy power generation, it can easily have a significant impact on the stable and reliable operation of the power grid. Therefore, large-scale energy storage technology, as an important means to solve this problem, has been widely used in renewable energy power generation. Among them, liquid flow battery energy storage technology is a representative technology for large-scale long-term energy storage systems.

[0003] As a new type of energy storage device, flow batteries are characterized by long life, environmental friendliness, and high safety. Their application in grid peak regulation, wind power, solar power, and other renewable energy generation applications can effectively improve grid stability and ensure grid security. Currently, the main types of flow batteries include all-vanadium flow batteries, zinc-bromine flow batteries, and iron-chromium flow batteries. Zinc-bromine batteries are simple batteries consisting of zinc bromide and a pair of electrodes. Compared to other batteries, they have high energy density, long cycle life, and low cost. Because the reaction rate on the bromine side of the bipolar plate in zinc-bromine batteries is lower than that on the zinc side, an active coating is prepared on the surface of the bromine-side electrode to increase the specific surface area of ​​that side, thereby increasing the reaction rate of the bromine-side electrode.

[0004] Currently, activated carbon is mainly used as the main material of the active coating on the market. However, the amount of bromine adsorbed in the activated carbon is too large. During the charging process of the zinc-bromine battery, zinc is precipitated on the negative plate and bromine is generated on the positive plate. When the bromine concentration is too high, it will diffuse to the negative electrode, dissolve the zinc on the negative plate, and generate zinc ions and bromide ions, which will cause self-discharge during charging and affect the battery efficiency. That is, although the use of activated carbon to prepare the active coating increases the specific surface area of ​​the bromine side electrode, the excessive bromine adsorbed in the activated carbon can easily cause the zinc-bromine battery stack to self-discharge, and the battery efficiency is relatively low. Summary of the Invention

[0005] In view of this, the present application proposes a method for preparing a zinc-bromine liquid flow battery bipolar plate, a bipolar plate and a zinc-bromine liquid flow battery to solve the above problems.

[0006] According to a first aspect of the present disclosure, a method for preparing a zinc-bromine flow battery bipolar plate is provided, comprising the following steps:

[0007] S1. Obtain polyethylene, carbon black, and graphite, and mix them according to a preset ratio to prepare a mixed material;

[0008] S2, processing the mixed material by at least one of hot pressing or extrusion to form a carbon plastic sheet;

[0009] S3, obtain activated carbon fiber, and mix with the carbon plastic sheet at a temperature of 148°C-160°C and a pressure of 20kgf / cm 2 -30kgf / cm 2 The bipolar plate is obtained by thermoplastic treatment, wherein the preferred temperature is 160°C and the preferred pressure is 20 kgf / cm 2 .

[0010] As an optional implementation scheme of the present application, optionally, in step S1, the preset ratio is 6:1:3.

[0011] As an optional embodiment of the present application, optionally, in step S1, the polyethylene is high-density polyethylene.

[0012] As an optional embodiment of the present application, optionally, in step S3, activated carbon fibers are obtained, and the activated carbon fibers and the carbon plastic sheet are subjected to a hot pressing process using a thermoplastic method under preset conditions to produce a bipolar plate, including:

[0013] S301, obtaining activated carbon fibers;

[0014] S302, placing the activated carbon fiber and the carbon plastic sheet in a metal mold;

[0015] S303, attaching the activated carbon fiber to one side of the carbon plastic sheet;

[0016] S304, set the metal mold temperature to 160 ° C and the pressure to 20 kgf / cm 2 The activated carbon fibers and the carbon plastic sheet were hot-pressed for 5 minutes using a thermoplastic method to produce a bipolar plate and the charge-discharge performance was tested.

[0017] As an optional embodiment of the present application, optionally, in step S304, the bromine adhesion retention of the activated carbon fiber is 2.0-2.5 mAh / cm 2 .

[0018] As an optional embodiment of the present application, optionally, in step S304, the bromine adhesion retention of the activated carbon fiber is 2.001 mAh / cm 2 .

[0019] In a second aspect of the present disclosure, a bipolar plate is provided, which is manufactured using the above-mentioned method for preparing a zinc-bromine flow battery bipolar plate, wherein the activated carbon fiber is the positive electrode and the carbon plastic sheet is the negative electrode.

[0020] A third aspect of the present disclosure provides a zinc-bromine flow battery, comprising:

[0021] The bipolar plate of the second aspect;

[0022] An electrolyte is stored in an electrolyte storage tank and distributed to the positive and negative electrodes of the bipolar plates through pipes;

[0023] A circulation pump is used to circulate the electrolyte.

[0024] As an optional embodiment of the present application, optionally, the electrolyte includes zinc bromide, zinc chloride, potassium chloride and 2-methyl-5-ethylpyridine.

[0025] As an optional embodiment of the present application, optionally, the electrolyte includes 2.25 mol / L zinc bromide, 0.5 mol / L zinc chloride, 1 mol / L potassium chloride and 0.8 mol / L 2-methyl-5-ethylpyridine.

[0026] Beneficial effects of this application:

[0027] 1. The bipolar plates for zinc-bromine flow batteries are made by hot-pressing polyethylene, carbon black, and graphite into carbon-plastic sheets. Activated carbon fibers are thermoplastically bonded to one side of the carbon-plastic sheet. Compared to activated carbon, activated carbon fibers are less susceptible to excessive bromine adsorption. This prevents self-discharge during charging, which occurs when excess bromine reacts with zinc on the negative plate to produce zinc and bromide ions, thereby minimizing the impact on battery efficiency.

[0028] 2. The hot pressing conditions of carbon plastic sheet and activated carbon fiber are as follows: temperature 160℃, pressure 20kgf / cm 2 It should be noted that hot pressing at 160°C can effectively ensure the bonding of activated carbon fibers with the carbon plastic sheet, prevent the activated carbon fibers from being pressed in too little, and ensure the normal use of the bipolar plate; at the same time, at 20kgf / cm 2 Hot pressing the activated carbon fibers and carbon plastic sheets under high pressure can effectively prevent the activated carbon fibers from being damaged, ensuring their normal use as active layers and thus ensuring the energy efficiency of zinc-bromine batteries.

[0029] Other features and aspects of the present application will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the application and, together with the description, serve to explain the principles of the application.

[0031] Figure 1 The structure diagram of the activated carbon fiber and carbon plastic sheet before hot pressing in the embodiment of the present application is shown;

[0032] Figure 2 The structure diagram of the activated carbon fiber and carbon plastic sheet after hot pressing in the embodiment of the present application is shown;

[0033] Figure 3 A comparison of the bromine adhesion amount of the positive electrode of the zinc-bromine flow battery of Examples 1 to 4 of the present application and Comparative Example 1 is shown;

[0034] Figure 4 A comparison chart of the charge and discharge efficiency of Examples 1 to 4 of the present application and Comparative Example 1 is shown. DETAILED DESCRIPTION

[0035] Various exemplary embodiments, features, and aspects of the present application will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0036] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application or simplifying the description, and do 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 therefore should not be understood as a limitation on the present application.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0038] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0039] In addition, numerous specific details are provided in the detailed description below to better illustrate the present application. Those skilled in the art will appreciate that the present application can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present application.

[0040] like Figure 1 and Figure 2 According to one aspect of the present disclosure, a method for preparing a zinc-bromine flow battery bipolar plate is provided, comprising the following steps:

[0041] S1. Obtain polyethylene, carbon black, and graphite, and mix them according to a preset ratio to prepare a mixed material;

[0042] In this embodiment, the preset ratio of polyethylene, carbon black and graphite is preferably 6:1:3, and the mixture is prepared by mixing with this ratio of components, and the polyethylene is preferably prepared by high-density polyethylene.

[0043] S2, processing the mixed material by at least one of hot pressing and extrusion to form a carbon plastic sheet 200;

[0044] S3, obtaining activated carbon fibers 100, and the carbon plastic sheet at a temperature of 148°C-160°C and a pressure of 20 kgf / cm 2 -30kgf / cm 2 The bipolar plate is prepared by thermoplastic method.

[0045] As an optional embodiment of the present application, optionally, in step S3, activated carbon fibers are obtained, and the activated carbon fibers and the carbon plastic sheet are subjected to a hot pressing process using a thermoplastic method under preset conditions to produce a bipolar plate, including:

[0046] S301, obtaining activated carbon fibers;

[0047] S302, placing the activated carbon fiber and the carbon plastic sheet in a metal mold;

[0048] S303, attaching the activated carbon fiber to one side of the carbon plastic sheet;

[0049] S304, set the metal mold temperature to 160 ° C and the pressure to 20 kgf / cm 2 The activated carbon fibers and the carbon plastic sheet were hot-pressed for 5 minutes using a thermoplastic method to produce a bipolar plate and the charge-discharge performance was tested.

[0050] As an optional embodiment of the present application, optionally, in step S304, the bromine adhesion retention of the activated carbon fiber is 2.0-2.5 mAh / cm 2 .

[0051] In this embodiment, it should be noted that the overall electrode reaction of the zinc-bromine battery is: Among them, the reaction equation during charging is as follows:

[0052] negative electrode: positive electrode:

[0053] That is, when the zinc-bromine battery is charged, zinc is deposited on the negative electrode and the bromine generated at the positive electrode dissolves in the electrolyte.

[0054] The reaction equation of zinc-bromine battery during discharge is as follows:

[0055] negative electrode: positive electrode:

[0056] That is, when the zinc-bromine battery discharges, the zinc on the negative electrode is oxidized to zinc ions and the bromine is reduced to bromide ions, both of which are dissolved in the electrolyte.

[0057] It should be noted that during the charging process of zinc-bromine batteries, the concentration of bromine generated increases. When the bromine concentration is excessive, it diffuses to the negative electrode and reacts with zinc to form zinc ions and bromide ions, causing the zinc-bromine battery to self-discharge during charging, resulting in low battery efficiency. Therefore, this application uses activated carbon fibers to prepare bipolar plates, and the amount of bromine adsorbed in the activated carbon fibers is maintained at 2.0-2.5 mAh / cm 2 When the bromine content is within this range, the self-discharge of zinc-bromine batteries can be effectively prevented, and the battery efficiency can be improved. Furthermore, the optimal bromine adhesion retention capacity of activated carbon fibers is 2.001 mAh / cm 2 , it is not easy to react with zinc to produce heat.

[0058] In a second aspect of the present disclosure, a bipolar plate is provided, which is manufactured using the above-mentioned method for preparing a zinc-bromine flow battery bipolar plate, wherein the activated carbon fiber side is the positive electrode and the carbon plastic sheet is the negative electrode.

[0059] A third aspect of the present disclosure provides a zinc-bromine flow battery, comprising:

[0060] The bipolar plate of the second aspect;

[0061] The electrolyte is stored in an electrolyte storage tank and distributed to the positive and negative electrodes of the bipolar plates through pipes;

[0062] Circulation pump, used to circulate the electrolyte.

[0063] As an optional embodiment of the present application, optionally, the electrolyte includes zinc bromide, zinc chloride, potassium chloride and 2-methyl-5-ethylpyridine.

[0064] As an optional embodiment of the present application, optionally, the electrolyte includes 2.25 mol / L zinc bromide, 0.5 mol / L zinc chloride, 1 mol / L potassium chloride and 0.8 mol / L 2-methyl-5-ethylpyridine.

[0065] In this embodiment, the activated carbon fiber is the positive electrode of the zinc-bromine flow battery, the carbon plastic sheet is the negative electrode of the zinc-bromine flow battery, and the electrolyte is distributed to the positive and negative plates respectively through a circulation pump. In this embodiment, the electrolyte includes 2.25 mol / L zinc bromide, 0.5 mol / L zinc chloride, 1 mol / L potassium chloride and 0.8 mol / L 2-methyl-5-ethylpyridine.

[0066] Example 1

[0067] Polyethylene, carbon black and graphite were mixed in a ratio of 6:1:3 and then hot pressed to form a carbon plastic sheet. Activated carbon fibers were obtained and placed in a metal mold with the carbon plastic sheet. The activated carbon fibers were attached to one side of the carbon plastic sheet. The metal mold temperature was set to 160°C and the pressure to 30 kgf / cm 2 The bipolar plate was made by hot pressing for 5 minutes using a thermoplastic method. The activated carbon fiber side was used as the positive electrode of the zinc-bromine flow battery, and the carbon plastic sheet was used as the negative electrode of the zinc-bromine flow battery. 2.25 mol / L zinc bromide, 0.5 mol / L zinc chloride, 1 mol / L potassium chloride and 0.8 mol / L 2-methyl-5-ethylpyridine aqueous solution were used as the electrolyte to prepare the zinc-bromine flow battery. The current density was 20 mA / cm 2 , test the charge and discharge performance.

[0068] Example 2

[0069] Polyethylene, carbon black and graphite were mixed in a ratio of 6:1:3 and then hot pressed to form a carbon plastic sheet. Activated carbon fibers were obtained and placed in a metal mold with the carbon plastic sheet. The activated carbon fibers were attached to one side of the carbon plastic sheet. The metal mold temperature was set to 160°C and the pressure was set to 20 kgf / cm 2 The bipolar plate was made by hot pressing for 5 minutes using a thermoplastic method. The activated carbon fiber side was used as the positive electrode of the zinc-bromine flow battery, and the carbon plastic sheet was used as the negative electrode of the zinc-bromine flow battery. 2.25 mol / L zinc bromide, 0.5 mol / L zinc chloride, 1 mol / L potassium chloride and 0.8 mol / L 2-methyl-5-ethylpyridine aqueous solution were used as the electrolyte to prepare the zinc-bromine flow battery. The current density was 20 mA / cm 2 , test the charge and discharge performance.

[0070] Example 3

[0071] Polyethylene, carbon black and graphite were mixed in a ratio of 6:1:3 and then hot pressed to form a carbon plastic sheet. Activated carbon fibers were obtained and placed in a metal mold with the carbon plastic sheet. The activated carbon fibers were attached to one side of the carbon plastic sheet. The metal mold temperature was set to 148°C and the pressure was set to 20 kgf / cm 2The bipolar plate was made by hot pressing for 5 minutes using a thermoplastic method. The activated carbon fiber side was used as the positive electrode of the zinc-bromine flow battery, and the carbon plastic sheet was used as the negative electrode of the zinc-bromine flow battery. 2.25 mol / L zinc bromide, 0.5 mol / L zinc chloride, 1 mol / L potassium chloride and 0.8 mol / L 2-methyl-5-ethylpyridine aqueous solution were used as the electrolyte to prepare the zinc-bromine flow battery. The current density was 20 mA / cm 2 , test the charge and discharge performance.

[0072] Example 4

[0073] Polyethylene, carbon black and graphite were mixed in a ratio of 6:1:3 and then hot pressed to form a carbon plastic sheet. Activated carbon fibers were obtained and placed in a metal mold with the carbon plastic sheet. The activated carbon fibers were attached to one side of the carbon plastic sheet. The metal mold temperature was set to 140°C and the pressure was set to 20 kgf / cm 2 The bipolar plate was made by hot pressing for 5 minutes using a thermoplastic method. The activated carbon fiber side was used as the positive electrode of the zinc-bromine flow battery, and the carbon plastic sheet was used as the negative electrode of the zinc-bromine flow battery. 2.25 mol / L zinc bromide, 0.5 mol / L zinc chloride, 1 mol / L potassium chloride and 0.8 mol / L 2-methyl-5-ethylpyridine aqueous solution were used as the electrolyte to prepare the zinc-bromine flow battery. The current density was 20 mA / cm 2 , test the charge and discharge performance.

[0074] Comparative Example 1

[0075] Polyethylene, carbon black and graphite were mixed in a ratio of 6:1:3 and then hot-pressed to form a carbon plastic sheet. Activated carbon was obtained and placed in a metal mold with the carbon plastic sheet. The activated carbon was placed on one side of the carbon plastic sheet. The metal mold temperature was set to 160°C and the pressure was set to 20 kgf / cm 2 The bipolar plate was made by hot pressing for 5 minutes using a thermoplastic method. The activated carbon side was used as the positive electrode of the zinc-bromine flow battery, and the carbon plastic sheet was used as the negative electrode of the zinc-bromine flow battery. The zinc-bromine flow battery was prepared using 2.25 mol / L zinc bromide, 0.5 mol / L zinc chloride, 1 mol / L potassium chloride and 0.8 mol / L 2-methyl-5-ethylpyridine aqueous solution as the electrolyte. The current density was 20 mA / cm 2 , test the charge and discharge performance.

[0076] The positive electrode bromine adhesion amount of Example 1, Example 2, Example 3, Example 4 and Comparative Example 1 was tested, and the test results are shown in Table 1:

[0077] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 <![CDATA[Bromine attachment amount mAh / cm 2 > 1.542 2.001 2.261 2.489 3.243

[0078] Table 1 Bromine adhesion amount of zinc-bromine flow battery cathode

[0079] According to Table 1 and Figure 3 It can be seen that when a carbon plastic sheet is prepared using polyethylene, carbon black and graphite in a ratio of 6:1:3, and activated carbon is hot-pressed on one side of the carbon plastic sheet to prepare a zinc-bromine flow battery bipolar plate, the amount of bromine adsorbed on the activated carbon used as the positive electrode of the zinc-bromine flow battery is too large. The excess bromine easily reacts with zinc, causing the zinc-bromine flow battery to self-discharge, affecting the battery efficiency. When the activated carbon fiber is hot-pressed on one side of the carbon plastic sheet, the hot pressing conditions are set to 160°C and 20kgf / cm 2 When the amount of bromine adsorbed in the positive electrode activated carbon fiber is appropriate, the specific bromine attachment amount is 2.001mAh / cm 2 It is not easy to have self-discharge. It should be noted that when the temperature of hot pressing carbon plastic sheet and activated carbon fiber is below 148℃, it is easy to cause too little activated carbon fiber to be pressed in, and it cannot be effectively combined with carbon plastic sheet, affecting the normal use of zinc-bromine flow battery. When the pressure of hot pressing carbon plastic sheet and activated carbon fiber is 30kgf / cm 2 When the above conditions are met, the activated carbon fiber is easily damaged and cannot be used as an active layer. In summary, the activated carbon fiber and carbon plastic sheet are hot pressed, and the hot pressing conditions are set to 160℃ and 20kgf / cm 2 At the same time, it can effectively ensure the utilization efficiency of zinc-bromine flow batteries and prevent self-discharge from affecting battery efficiency.

[0080] Furthermore, the specific charge and discharge efficiency of Example 1, Example 2, Example 3, Example 4 and Comparative Example 1 was tested, and the test results are shown in Table 2:

[0081] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Current efficiency% 90.33 94.21 93.87 93.31 84.80 Voltage efficiency % 83.82 86.10 82.80 79.09 83.23 Energy efficiency % 75.72 81.11 77.72 73.80 70.57

[0082] Table 2 Battery charge and discharge efficiency

[0083] The charge and discharge efficiency of zinc-bromine flow batteries is as follows Figure 4 As shown in Table 2, it should be noted that Figure 4 The current efficiency, voltage efficiency and energy efficiency of Example 1, Example 2, Example 3, Example 4 and Comparative Example 1 are shown from left to right. Specifically, the current efficiency, voltage efficiency and energy efficiency of the zinc-bromine flow battery prepared in Example 2 are the highest, with specific values ​​of 94.21%, 86.10% and 81.11% respectively. 2 The zinc-bromine flow battery prepared by hot pressing under the above conditions has the highest efficiency and can effectively prevent the occurrence of self-discharge.

[0084] The embodiments of the present application have been described above. The above description is illustrative and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or improvements to the technology in the market, or to enable other persons skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing a zinc-bromine flow battery bipolar plate, characterized in that: The steps include: S1. Obtain polyethylene, carbon black, and graphite, and mix them according to a preset ratio to prepare a mixed material; S2, processing the mixed material by at least one of hot pressing or extrusion to form a carbon plastic sheet; S3, obtain activated carbon fiber, and the carbon plastic sheet at a temperature of 160 ° C and a pressure of 20 kgf / cm 2 The bipolar plate is prepared by thermoplastic treatment; When hot pressing the activated carbon fiber on one side of the carbon plastic sheet, the hot pressing conditions are set to 160°C and 20kgf / cm 2 When the amount of bromine adsorbed in the positive electrode activated carbon fiber is appropriate, the specific bromine attachment amount is 2.001mAh / cm 2 Less prone to self-discharge; The obtained activated carbon fiber and the carbon plastic sheet are heated at a temperature of 160°C and a pressure of 20 kgf / cm 2 The bipolar plate is prepared by thermoplastic method, including: S301, obtaining activated carbon fibers; S302, placing the activated carbon fiber and the carbon plastic sheet in a metal mold; S303, attaching the activated carbon fiber to one side of the carbon plastic sheet; S304, set the metal mold temperature to 160 ° C and the pressure to 20 kgf / cm 2 , hot-pressing the activated carbon fibers and the carbon plastic sheet for 5 minutes using a thermoplastic method to produce a bipolar plate and testing its charge and discharge performance; The bromine adhesion retention capacity of the activated carbon fiber is 2.001 mAh / cm 2 .

2. The method for preparing a zinc-bromine flow battery bipolar plate according to claim 1, wherein: In step S1, the preset ratio is 6:1:

3.

3. The method for preparing a zinc-bromine flow battery bipolar plate according to claim 1, wherein: In step S1, the polyethylene is high-density polyethylene.

4. A bipolar plate, characterized in that: The bipolar plate is made by the preparation method of the zinc-bromine liquid flow battery bipolar plate according to any one of claims 1 to 3, wherein the activated carbon fiber is the positive electrode and the carbon plastic sheet is the negative electrode.

5. A zinc-bromine flow battery, characterized in that: include: The bipolar plate according to claim 4; An electrolyte is stored in an electrolyte storage tank and distributed to the positive and negative electrodes of the bipolar plates through pipes; A circulation pump is used to circulate the electrolyte.

6. The zinc-bromine flow battery according to claim 5, characterized in that The electrolyte includes zinc bromide, zinc chloride, potassium chloride and 2-methyl-5-ethylpyridine.

7. The zinc-bromine flow battery according to claim 5, characterized in that The electrolyte includes 2.25 mol / L zinc bromide, 0.5 mol / L zinc chloride, 1 mol / L potassium chloride and 0.8 mol / L 2-methyl-5-ethylpyridine.

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