Electrode frame and zinc-bromine flow battery

Abstract

The present invention provides an electrode frame and a zinc-bromine flow battery. The electrode frame of the present invention includes a positive electrode frame and a negative electrode frame; it is a hollow annular flat plate body, including a through hole opened on the side wall of the annular flat plate body and connected to the hollow area, a positive electrolyte inlet flow channel and a positive electrolyte outlet flow channel arranged on the electrode frame, and a negative electrolyte inlet flow channel and a negative electrolyte outlet flow channel arranged on the electrode frame; the hollow area is used to accommodate electrodes; the technical solution of the present invention greatly reduces the resistance of the electrode frame to the flow of electrolyte, and can increase the electrolyte flow rate through the zinc-bromine single-liquid flow stack while ensuring that the head of the electrolyte pump remains unchanged, increase the electrolyte flow rate of the negative electrode side electrode, improve the uniformity of zinc deposition, and increase the service life of the zinc-bromine single-liquid flow stack.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid flow battery energy storage, and in particular to an electrode frame and a zinc-bromine liquid flow battery. Background Art

[0002] In today's society, governments of various countries pay more and more attention to the use of renewable energy, and gradually increase its proportion in the energy structure. They have introduced policies to vigorously support the development of renewable energy. Against this background, the supporting industries of solar and wind power generation have ushered in unprecedented opportunities. With the influx of a large amount of capital, some key technical problems of renewable energy have been broken through one after another, and more and more photovoltaic power stations and wind power stations have been put into use. However, renewable energy generally has the characteristics of instability and discontinuity, and cannot be directly connected to the grid for use. Large-scale energy storage technology is an effective means to solve this problem. Storing the electricity generated by renewable energy in a large-scale energy storage system and inputting it into the grid with stable power can effectively improve the quality of grid connection and increase the utilization rate of renewable energy. Liquid flow batteries, as a chemical energy storage and conversion system, have received widespread attention from experts, scholars and enterprises.

[0003] Aqueous zinc-based flow battery is an energy storage technology with obvious cost and safety advantages. The reason is that the negative electrode has a high volume-to-weight capacity (5854 mAh cm -3 , 820mAh g -1 ), lower potential (-0.76V vs. standard hydrogen electrode), two-electron transfer, abundant reserves, and low-cost zinc deposition / dissolution reaction. The characteristic of liquid flow batteries is that the active material is stored in the electrolyte, and the individual cells that make up the battery stack are connected in parallel on the liquid circuit. The electrolyte is distributed to each single cell through the common pipeline of the battery stack and the flow channel on each electrode frame, flows into the electrode, and reacts. Therefore, the uniformity of the electrolyte distribution in each single cell is the key to reducing the extreme difference between cells.

[0004] Zinc-bromine single-flow battery is a kind of energy storage technology. Because of its low cost, long cycle life and high efficiency, it has attracted the attention of more and more enterprises, experts and scholars. Its characteristics are that the negative electrode utilizes the deposition and dissolution reaction of zinc, and the positive electrode undergoes a reversible reaction of bromine and bromide ions, and the generated bromine is enclosed in the positive electrode cavity filled with electrolyte. It is mainly used in large-scale energy storage fields such as grid peak regulation, wind power or solar power generation. The flow of electrolyte in the electrode is the main feature that distinguishes flow batteries from other battery systems, so the flow and distribution of electrolyte in the battery is crucial. The flow path design of the negative electrode electrolyte of the existing zinc-bromine single-flow battery is that the electrolyte is unevenly distributed in each battery cell, which in turn causes uneven deposition of negative electrode zinc between the battery cells and uneven distribution on large-area electrodes, which seriously affects the cycle stability and charge and discharge efficiency of the battery pack. Summary of the invention

[0005] According to the technical problems raised above, an electrode frame structure is provided to improve the uniformity of electrolyte distribution in each single cell of the battery stack. The electrode frame material is PVC polyvinyl chloride. The present invention adopts a dual-path inlet and outlet design and two-stage mixed flow. Its straight-in and straight-out electrolyte inlet and outlet design increases the electrolyte flow area and reduces fluid resistance.

[0006] The technical means adopted by the present invention are as follows:

[0007] An electrode frame, comprising a positive electrode frame and a negative electrode frame; the electrode frame is a hollow annular flat plate body, comprising a through hole opened on the side wall of the annular flat plate body and connected to the hollow area, a positive electrolyte inlet flow channel and a positive electrolyte outlet flow channel arranged on the positive electrode frame, and a negative electrolyte inlet flow channel and a negative electrolyte outlet flow channel arranged on the negative electrode frame, and the hollow area is used to accommodate electrodes.

[0008] Furthermore, the through holes are symmetrically arranged on the side walls of the annular flat body, and the side walls of the annular flat body are provided with a first through hole, a second through hole, a third through hole, a fourth through hole, a fifth through hole, a sixth through hole, a seventh through hole, and an eighth through hole perpendicular to the surface of the annular flat body in sequence in a clockwise direction.

[0009] The first through hole is used as a first inlet flow channel A1 shared by the negative electrode electrolyte;

[0010] The second through hole is used as a second inlet flow channel A2 shared by the negative electrode electrolyte;

[0011] The third through hole is used as a first outlet flow channel B1 shared by the positive electrode electrolyte;

[0012] The fourth through hole is used as a first outlet flow channel B2 shared by the negative electrode electrolyte;

[0013] The fifth through hole is used as a first inlet flow channel C1 for the positive electrode electrolyte;

[0014] The sixth through hole is used as a first inlet flow channel C2 shared by the positive electrode electrolyte;

[0015] The seventh through hole is used as a second outlet flow channel D1 shared by the negative electrode electrolyte;

[0016] The eighth through hole serves as a second outlet channel D2 shared by the positive electrode electrolyte.

[0017] Furthermore, the first inlet flow channel A1 and the second inlet flow channel A2 are respectively connected to the middle through-hole region through the negative electrode electrolyte inlet flow channel;

[0018] The first outlet flow channel B1 and the first outlet flow channel B2 are respectively connected to the middle through-hole area through the negative electrode electrolyte outlet flow channel;

[0019] The first inlet flow channel C1 and the first inlet flow channel C2 are respectively connected to the middle through-hole area through the positive electrolyte inlet flow channel;

[0020] The second outlet flow channel D1 and the second outlet flow channel D2 are respectively connected to the middle through-hole area through the positive electrode electrolyte outlet flow channel.

[0021] Furthermore, a groove-shaped flow channel for connecting the first inlet flow channel A1 and the second inlet flow channel A2 of the negative electrode frame is provided between the first inlet flow channel A1 and the second inlet flow channel A2; the groove-shaped flow channel serves as a first-stage mixed flow area for the electrolyte to enter the negative electrode;

[0022] A communication channel for connecting the first inlet channel C1 and the second inlet channel C2 is provided between the first inlet channel C1 and the second inlet channel C2 of the positive electrode frame.

[0023] Furthermore, the positive electrode electrolyte inlet flow channel and the positive electrode electrolyte outlet flow channel are provided with a first cover sheet for covering the flow channels; the negative electrode electrolyte inlet flow channel and the negative electrode electrolyte outlet flow channel are provided with a second cover sheet for covering the flow channels.

[0024] Furthermore, the first cover plate and the second cover plate each include two parts, the first part is embedded in the electrode frame, and the second part extends to the through hole in the electrode frame for accommodating the electrode, and both parts are trapezoidal structures.

[0025] Furthermore, a protruding structure is provided on the second portion of the cover sheet extending to the through hole in the electrode frame for accommodating the electrode, and a cavity structure is formed at the edge of the negative electrode carbon felt, and the cavity structure serves as a secondary mixed flow area.

[0026] The present invention also provides a zinc-bromine liquid flow battery, comprising the above-mentioned electrode frame, wherein the zinc-bromine liquid flow battery comprises a battery pack formed by more than two single cells connected in series, wherein the single cell comprises a negative electrode arranged in the middle through hole area of ​​the above-mentioned negative electrode frame, a diaphragm, or a positive electrode arranged in the middle through hole area of ​​the above-mentioned positive electrode frame.

[0027] Furthermore, the first inlet flow channel A1 of each adjacent electrode frame in the battery pack is connected in sequence, the second inlet flow channel A2 is connected in sequence, the first inlet flow channel C1 is connected in sequence, the second inlet flow channel C2 is connected in sequence, the first outlet flow channel B1 is connected in sequence, the first outlet flow channel B2 is connected in sequence, the second outlet flow channel D1 is connected in sequence, and the second outlet flow channel D2 is connected in sequence.

[0028] Furthermore, the first inlet flow channel A1 of each adjacent electrode frame in the battery pack is connected in sequence, the second inlet flow channel A2 is connected in sequence, the first inlet flow channel C1 is connected in sequence, the second inlet flow channel C2 is connected in sequence, the first outlet flow channel B1 is connected in sequence, the first outlet flow channel B2 is connected in sequence, the second outlet flow channel D1 is connected in sequence, and the second outlet flow channel D2 is connected in sequence.

[0029] Furthermore, after the battery pack is assembled, the negative electrode electrolyte flows into two flow paths, A1 and A2, when the battery pack is in operation;

[0030] Flow path A1: the negative electrode electrolyte flows into the first inlet flow channel A1, flows into the negative electrode frame through the negative electrode electrolyte inlet flow channel, flows out of the negative electrode frame from the negative electrode electrolyte outlet flow channel to the first outlet flow channel B1 and the second outlet flow channel B2, and flows out of the battery pack;

[0031] Flow path A2: the negative electrode electrolyte flows into the second inlet flow channel A2, flows into the negative electrode frame through the negative electrode electrolyte inlet flow channel, flows out of the negative electrode frame from the negative electrode electrolyte outlet flow channel to the first outlet flow channel B1 and the second outlet flow channel B2, and flows out of the battery pack;

[0032] The negative electrode electrolyte flows in the first inlet flow channel A1 and the second inlet flow channel A2 in the same or opposite directions.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] 1. The flow channel grooves of the electrode frame provided by the present invention all adopt a straight-through and short-flow design, which effectively reduces the flow resistance; the design adopts a two-stage mixing chamber for mixing flow, which can make the electrolyte more evenly distributed in the electrode.

[0035] 2. The present invention greatly reduces the resistance of the electrode frame to the flow of the electrolyte, and can increase the electrolyte flow rate through the zinc-bromine single-liquid flow stack while ensuring that the lift of the electrolyte pump remains unchanged, increase the electrolyte flow rate of the negative electrode, improve the uniformity of zinc deposition, and increase the service life of the zinc-bromine single-liquid flow stack.

[0036] 3. Compared with the single-direction liquid inlet method of the prior art with a single liquid inlet channel, the opposing bidirectional liquid inlet method with double liquid inlet channels and the design of a two-stage mixed flow structure improve the uniformity of the flow rate of each cell in the battery pack, thereby improving the cycle efficiency and life of the battery.

[0037] Based on the above reasons, the present invention can be widely promoted in the fields of liquid flow battery energy storage and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0039] Figure 1 The material composition and location of a single battery.

[0040] Figure 2 It is the negative electrode frame structure of the traditional zinc-bromine flow battery stack.

[0041] Figure 3 This is the electrolyte flow mode of the traditional zinc-bromine flow battery stack.

[0042] Figure 4 The invention discloses a zinc-bromine liquid flow battery stack electrode frame structure.

[0043] Figure 5 This is the electrolyte flow mode of the zinc-bromine liquid flow battery stack of the present invention. DETAILED DESCRIPTION

[0044] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0045] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0047] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, the numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0048] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0049] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0050] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0051] Comparative Example

[0052] like Figure 1 As shown in FIG. 1 , it is a schematic diagram of the composition and position of each material in a single battery. The zinc-bromine single flow battery stack in this comparative example uses a traditional negative electrode frame structure. Figure 2 As shown, through holes are respectively arranged at the edges of the electrode frame near the four corners, and the four through holes are respectively used as the cathode electrolyte inlet, cathode electrolyte outlet, anode electrolyte inlet and anode electrolyte outlet; a hollow rectangular middle through hole that can accommodate a porous electrode is arranged in the middle of the rectangular flat plate; on the surface of one side of the electrode frame, the electrode frame surface near the two opposite sides of the rectangular middle through hole is respectively provided with upper and lower liquid distribution grooves, which are respectively used as the cathode electrolyte inlet distribution groove and the cathode electrolyte outlet distribution groove, the inlet distribution groove is connected to the cathode electrolyte inlet through the inlet main flow channel groove, and the outlet distribution groove is connected to the cathode electrolyte outlet through the outlet main flow channel groove; the inlet distribution groove is connected to the middle through hole through the inlet liquid distribution flow channel, and the outlet distribution groove is connected to the middle through hole through the outlet liquid distribution flow channel (or groove); the electrode frame, as one pole of the battery, plays the role of organizing the flow of electrolyte and supporting the electrode during operation. The cross-sectional length of the electrolyte inlet is 16.75mm. A portion of the electrolyte flows through the electrolyte inlet through-hole, through the inlet main channel groove to the center of the electrode frame, and flows into the inlet liquid separation channel through the inlet distribution groove. After the electrolyte reacts in the porous electrode area, it flows to the center of the electrode frame through the outlet distribution groove, and flows out of the electrode frame through the outlet main channel groove. The cross-sectional width of the inlet and outlet main channel grooves is 8mm. The inlet liquid separation channel and the outlet liquid separation channel both adopt a gradually expanding design, and the cross-sectional width of the inlet liquid separation channel, the outlet liquid separation channel and the porous electrode is 3mm. The frame material is PVC. Adopt such as Figure 3 The conventional electrolyte flow pattern is shown.

[0053] Electrode area: 875cm 2 .

[0054] Number of battery stack sections: 10.

[0055] Current density: 40mA / cm 2 , charging time: 1 hour, discharge cut-off voltage: 8V.

[0056] The battery stack has a charge and discharge coulomb efficiency of 94.1%, a voltage efficiency of 82.3%, and an energy efficiency of 77.4%.

[0057] Maximum number of charge and discharge cycles: 305 cycles.

[0058] Example

[0059] The zinc-bromine single flow battery stack in this embodiment uses the electrode frame structure of the present invention, such as Figure 4As shown, a rectangular electrode frame is provided in this embodiment, and the electrode frame includes a positive electrode frame and a negative electrode frame; the electrode frame is a hollow annular flat plate body, including a through hole opened on the side wall of the annular flat plate body and connected to the hollow area, a positive electrolyte inlet flow channel and a positive electrolyte outlet flow channel arranged on the positive electrode frame, and a negative electrolyte inlet flow channel and a negative electrolyte outlet flow channel arranged on the negative electrode frame, and the hollow area accommodates the electrodes.

[0060] The through holes are symmetrically arranged on the side wall of the annular flat body, and the side wall of the annular flat body is provided with a first through hole, a second through hole, a third through hole, a fourth through hole, a fifth through hole, a sixth through hole, a seventh through hole, and an eighth through hole perpendicular to the surface of the annular flat body in a clockwise direction; the first through hole serves as a first inlet flow channel A1 shared by the negative electrode electrolyte; the second through hole serves as a second inlet flow channel A2 shared by the negative electrode electrolyte; the third through hole serves as a first outlet flow channel B1 shared by the positive electrode electrolyte; the fourth through hole serves as a first outlet flow channel B2 shared by the negative electrode electrolyte; the fifth through hole serves as a first inlet flow channel C1 shared by the positive electrode electrolyte; the sixth through hole serves as a first inlet flow channel C2 shared by the positive electrode electrolyte; the seventh through hole serves as a second outlet flow channel D1 shared by the negative electrode electrolyte; and the eighth through hole serves as a second outlet flow channel D2 shared by the positive electrode electrolyte. Among them, the first inlet flow channel A1 and the second inlet flow channel A2 are respectively connected to the middle through-hole area through the negative electrolyte inlet flow channel; the first outlet flow channel B1 and the first outlet flow channel B2 are respectively connected to the middle through-hole area through the negative electrolyte outlet flow channel; the first inlet flow channel C1 and the first inlet flow channel C2 are respectively connected to the middle through-hole area through the positive electrolyte inlet flow channel; the second outlet flow channel D1 and the second outlet flow channel D2 are respectively connected to the middle through-hole area through the positive electrolyte outlet flow channel.

[0061] A groove-shaped flow channel for connecting the first inlet flow channel A1 and the second inlet flow channel A2 of the negative electrode frame is provided between the first inlet flow channel A1 and the second inlet flow channel A2; the groove-shaped flow channel is used as the first-level mixed flow area for the electrolyte to enter the negative electrode; a connecting flow channel for connecting the first inlet flow channel C1 and the second inlet flow channel C2 of the positive electrode frame is provided between the first inlet flow channel C1 and the second inlet flow channel C2. In this embodiment, four grooves connecting the first-level mixed flow area and the cavity area accommodating the electrode are provided on the surface of the rectangular negative electrode frame as liquid inlet distribution grooves. The electrolyte passes through the two main channels of the inlet electrolyte and the first-level mixed flow area liquid inlet distribution grooves to reach the electrode for reaction in sequence. The four grooves are symmetrically distributed with the center line connecting the long side of the rectangular negative electrode frame. Among them, the center lines of the two middle liquid inlet distribution grooves are perpendicular to the center line of the first-level mixed flow groove. The two liquid inlet distribution grooves on both sides are connected to the liquid inlet of the main channel, and the angle between their center lines and the center line of the first-level mixed flow groove is 15 to 90°, preferably 13°, and extends to the short side of the rectangular electrode frame. Each liquid outlet main channel is provided with two grooves connecting the negative electrode liquid outlet main channel and the through hole area containing the electrode, and the grooves provided in the two main channels are symmetrically distributed with the midpoint of the long side of the rectangle as the center line. The angle between the center line of the groove and the long side of the rectangle is 5 to 20 degrees, preferably 9 degrees and 18 degrees.

[0062] A first cover sheet for covering the positive electrode electrolyte inlet flow channel and the positive electrode electrolyte outlet flow channel is provided; a second cover sheet for covering the flow channel is provided on the negative electrode electrolyte inlet flow channel and the negative electrode electrolyte outlet flow channel. The first cover sheet and the second cover sheet each include two parts, the first part is inserted into the electrode frame, and the second part extends to the through hole in the electrode frame for accommodating the electrode, and both parts are trapezoidal structures. A protruding structure is provided on the second part of the cover sheet extending to the through hole in the electrode frame for accommodating the electrode, and a cavity structure is formed with the edge of the negative electrode carbon felt, and the cavity structure serves as a secondary mixed flow area. The protruding structure in this embodiment is a uniformly arranged support column, which is in contact with the negative electrode current collector. After the battery is assembled, the baffle is supported to form a cavity.

[0063] The zinc-bromine liquid flow battery in this embodiment includes a battery pack formed by more than two single cells connected in series, and the single cell includes a negative electrode and a diaphragm arranged in the middle through-hole area of ​​the above-mentioned negative electrode frame, or a negative electrode arranged in the middle through-hole area of ​​the above-mentioned positive electrode frame. The first inlet flow channel A1 of each adjacent electrode frame in the battery pack is sequentially connected, the second inlet flow channel A2 is sequentially connected, the first inlet flow channel C1 is sequentially connected, the second inlet flow channel C2 is sequentially connected, the first outlet flow channel B1 is sequentially connected, the first outlet flow channel B2 is sequentially connected, the second outlet flow channel D1 is sequentially connected, and the second outlet flow channel D2 is sequentially connected. After assembling the battery pack, the negative electrode electrolyte flows into two flow paths A1 and A2 when the battery pack is running;

[0064] Flow path A1: the negative electrode electrolyte flows into the first inlet flow channel A1, flows into the negative electrode frame through the negative electrode electrolyte inlet flow channel, flows out of the negative electrode frame from the negative electrode electrolyte outlet flow channel to the first outlet flow channel B1 and the second outlet flow channel B2, and flows out of the battery pack;

[0065] Flow path A2: the negative electrode electrolyte flows into the second inlet flow channel A2, flows into the negative electrode frame through the negative electrode electrolyte inlet flow channel, flows out of the negative electrode frame from the negative electrode electrolyte outlet flow channel to the first outlet flow channel B1 and the second outlet flow channel B2, and flows out of the battery pack;

[0066] The negative electrode electrolyte flows in the first inlet flow channel A1 and the second inlet flow channel A2 in the same or opposite directions.

[0067] Using the electrolyte flow mode of the present invention, such as Figure 5 As shown, the inlet mode of the negative electrode electrolyte inlet channel is: the electrolyte in one of the inlet holes of the main channel enters in a direction perpendicular to the electrode frame plane, and the electrolyte in the other main channel enters in the opposite direction to the first main channel. The outlet mode of the negative electrode electrolyte outlet channel is: the electrolyte flows out in a direction perpendicular to the electrode frame, and the outlet directions of the two outlet main channels are the same.

[0068] Electrode area: 875cm 2 .

[0069] Number of battery stack sections: 10.

[0070] Current density: 40mA / cm 2 , charging time: 1 hour, discharge cut-off voltage: 8V.

[0071] The battery stack has a charge and discharge coulomb efficiency of 95.3%, a voltage efficiency of 84.2%, and an energy efficiency of 80.2%.

[0072] Maximum number of charge and discharge cycles: 413 cycles.

[0073] Table 1: Battery performance comparison

[0074] Stack number Coulombic efficiency % Voltage efficiency % Energy efficiency % Comparative Example 94.1 82.3 77.4 Example 95.3 84.2 80.2

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electrode frame, characterized in that: The electrode frame structure adopts a dual-path inlet and outlet design, two-stage mixed flow, and a straight-in and straight-out electrolyte inlet and outlet design to increase the electrolyte flow area and reduce fluid resistance, in order to improve the uniformity of electrolyte distribution of each single cell in the battery stack, including a positive electrode frame and a negative electrode frame; the electrode frame is a hollow annular flat body, including a through hole opened on the side wall of the annular flat body and connected to the hollow area, a positive electrolyte inlet flow channel and a positive electrolyte outlet flow channel arranged on the positive electrode frame, and a negative electrolyte inlet flow channel and a negative electrolyte outlet flow channel arranged on the negative electrode frame, and the hollow area is used to accommodate the electrode; The through holes are symmetrically arranged on the side wall of the annular flat body, and the side wall of the annular flat body is provided with a first through hole, a second through hole, a third through hole, a fourth through hole, a fifth through hole, a sixth through hole, a seventh through hole, and an eighth through hole which are perpendicular to the surface of the annular flat body in a clockwise direction; The first through hole is used as a first inlet flow channel A1 shared by the negative electrode electrolyte; The second through hole is used as a second inlet flow channel A2 shared by the negative electrode electrolyte; The third through hole is used as a first outlet flow channel B1 shared by the positive electrode electrolyte; The fourth through hole is used as a first outlet flow channel B2 shared by the negative electrode electrolyte; The fifth through hole is used as a first inlet flow channel C1 for the positive electrode electrolyte; The sixth through hole is used as a first inlet flow channel C2 shared by the positive electrode electrolyte; The seventh through hole is used as a second outlet flow channel D1 shared by the negative electrode electrolyte; The eighth through hole is used as a second outlet flow channel D2 for the positive electrode electrolyte; The first inlet flow channel A1 and the second inlet flow channel A2 are respectively connected to the middle through-hole area through the negative electrode electrolyte inlet flow channel; The first outlet flow channel B1 is connected to the middle through-hole area through the positive electrolyte outlet flow channel; The first outlet flow channel B2 is connected to the middle through-hole area through the negative electrode electrolyte outlet flow channel; The first inlet flow channel C1 and the first inlet flow channel C2 are respectively connected to the middle through-hole area through the positive electrolyte inlet flow channel; The second outlet flow channel D1 is connected to the middle through-hole area through the negative electrode electrolyte outlet flow channel; The second outlet flow channel D2 is connected to the middle through-hole area through the positive electrolyte outlet flow channel; A groove-shaped flow channel for connecting the first inlet flow channel A1 and the second inlet flow channel A2 of the negative electrode frame is provided between the first inlet flow channel A1 and the second inlet flow channel A2; the groove-shaped flow channel serves as a first-stage mixed flow area for the electrolyte to enter the negative electrode; four grooves connecting the first-stage mixed flow area and the cavity area accommodating the electrode are provided on the surface of the rectangular negative electrode frame as liquid inlet distribution grooves; The electrolyte passes through the first inlet flow channel A1, the second inlet flow channel A2, the first-stage mixed flow area, and the liquid inlet distribution groove of the inlet electrolyte in turn to reach the electrode for reaction; the first inlet flow channel A1 and the second inlet flow channel A2 form two main channels; the four grooves are symmetrically distributed to connect the center line of the long side of the rectangular negative electrode frame; wherein the center line of the two middle liquid inlet distribution grooves is perpendicular to the center line of the first-stage mixed flow groove; the two liquid inlet distribution grooves on both sides are respectively connected to the two main channels, and the angle between their center lines and the center line of the first-stage mixed flow groove is 15 to 90 degrees, and extend to the short side of the rectangular electrode frame; each liquid outlet main channel is provided with two grooves connecting the negative electrode liquid outlet main channel and the through hole area accommodating the electrode, and the grooves arranged in the two main channels are symmetrically distributed with the midpoint of the long side of the rectangle as the center line; wherein the angle between the center line of the grooves arranged in the two main channels and the long side of the rectangle is 5 to 20 degrees; The positive electrode electrolyte inlet flow channel and the positive electrode electrolyte outlet flow channel are provided with a first cover sheet for covering the flow channel; the negative electrode electrolyte inlet flow channel and the negative electrode electrolyte outlet flow channel are provided with a second cover sheet for covering the flow channel; the first cover sheet and the second cover sheet each include two parts, the first part is embedded in the electrode frame, and the second part extends to the through hole in the electrode frame for accommodating the electrode, and both parts are trapezoidal structures; the second part of the cover sheet extending to the through hole in the electrode frame for accommodating the electrode is provided with a protruding structure, and a cavity structure is formed at the edge of the negative electrode carbon felt, and the cavity structure serves as a secondary mixed flow area; the protruding structure is a uniformly arranged support column, the support column is in contact with the negative electrode current collector, and after the battery is assembled, the support cover sheet forms a cavity; The inlet method of the negative electrode electrolyte inlet main channel is as follows: the electrolyte of one of the main channel inlet holes enters in a direction perpendicular to the electrode frame plane, and the electrolyte of the other main channel enters in a direction opposite to the first main channel; The discharge method of the negative electrode electrolyte main discharge channel is as follows: the electrolyte flows out in a direction perpendicular to the electrode frame, and the discharge directions of the two main discharge channels are the same.

2. A zinc-bromine flow battery, characterized in that: The zinc-bromine flow battery comprises the electrode frame as described in claim 1, wherein the zinc-bromine flow battery comprises a battery pack formed by two or more single cells connected in series, and the single cell comprises a negative electrode and a diaphragm arranged in the middle through-hole area of ​​the negative electrode frame as described in claim 1, or a positive electrode arranged in the middle through-hole area of ​​the positive electrode frame as described in claim 1.

3. The zinc-bromine flow battery according to claim 2, characterized in that: The first inlet flow channels A1 of adjacent electrode frames in the battery pack are connected in sequence, the second inlet flow channels A2 are connected in sequence, the first inlet flow channels C1 are connected in sequence, the first inlet flow channels C2 are connected in sequence, the first outlet flow channels B1 are connected in sequence, the first outlet flow channels B2 are connected in sequence, the second outlet flow channels D1 are connected in sequence, and the second outlet flow channels D2 are connected in sequence.

4. The zinc-bromine flow battery according to claim 3, characterized in that: After the battery pack is assembled, the negative electrode electrolyte flows into two flow paths, A1 and A2, when the battery pack is running; Flow path A1: the negative electrode electrolyte flows into the first inlet flow channel A1, flows into the negative electrode frame through the negative electrode electrolyte inlet flow channel, flows out of the negative electrode frame from the negative electrode electrolyte outlet flow channel to the second outlet flow channel D1 and the second outlet flow channel B2, and flows out of the battery pack; Flow path A2: the negative electrode electrolyte flows into the second inlet flow channel A2, flows into the negative electrode frame through the negative electrode electrolyte inlet flow channel, flows out of the negative electrode frame from the negative electrode electrolyte outlet flow channel to the second outlet flow channel D1 and the second outlet flow channel B2, and flows out of the battery pack; The negative electrode electrolyte flows in the first inlet flow channel A1 and the second inlet flow channel A2 in the same or opposite directions.

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