Electrode and electrode frame composite assembly and method of making same, flow battery

Abstract

The application provides an electrode and electrode frame composite assembly, a preparation method thereof and a flow battery. The electrode and electrode frame composite assembly comprises an electrode frame and a carbon cloth electrode. The electrode frame is provided with first flow channels and second flow channels which are spaced apart. The first flow channels are provided with a plurality of first flow channel holes, and the second flow channels are provided with a plurality of second flow channel holes. The carbon cloth electrode is arranged between the first flow channels and the second flow channels. The carbon cloth electrode is provided with first electrode flow channels which are communicated with the first flow channel holes and second electrode flow channels which are communicated with the second flow channel holes. The electrode and electrode frame composite assembly is beneficial to improving the voltage efficiency and energy efficiency of the flow battery.

Description

Technical Field

[0001] This application relates to the field of flow battery technology, and in particular to an electrode and electrode frame composite assembly and its preparation method, and a flow battery. Background Technology

[0002] A flow battery is a novel type of rechargeable battery that stores energy in an electrolyte solution. Energy storage and release are achieved through the flow of the electrolyte within the battery and electrode reactions. A flow battery system mainly consists of a stack system, an electrolyte system, a control system, and auxiliary systems. The stack system primarily comprises bipolar plates, electrodes, an ion exchange membrane, an electrode frame / sealing gasket, end plates, and current collectors.

[0003] With the rapid development of flow battery technology, higher requirements have been placed on the voltage and energy efficiency of flow batteries. Therefore, how to further improve the voltage and energy efficiency of flow batteries has become one of the important research directions in this field. Summary of the Invention

[0004] Based on this, this application provides an electrode and electrode frame composite component and its preparation method, as well as a flow battery. The electrode and electrode frame composite component is beneficial to improving the voltage efficiency and energy efficiency of the flow battery.

[0005] The technical solution proposed in this application is as follows: According to a first aspect of this application, an electrode and electrode frame composite assembly is provided, including an electrode frame and a carbon cloth electrode. The electrode frame is provided with a first flow channel and a second flow channel spaced apart from each other. The first flow channel has a plurality of first flow channel holes, and the second flow channel has a plurality of second flow channel holes. The carbon cloth electrode is disposed on the electrode frame and located between the first flow channel and the second flow channel. The carbon cloth electrode has a first electrode flow channel communicating with the first flow channel holes and a second electrode flow channel communicating with the second flow channel holes.

[0006] The electrode and electrode frame composite assembly described above in this application comprises a carbon cloth electrode disposed between a first flow channel and a second flow channel. This carbon cloth electrode has a first electrode flow channel and a second electrode flow channel, with the first electrode flow channel connected to a first flow channel hole on the first flow channel, and the second electrode flow channel connected to a second flow channel hole on the second flow channel. Using this structure, the electrolyte enters the first electrode flow channel and / or the second electrode flow channel of the carbon cloth electrode from the first flow channel hole and / or the second flow channel hole of the electrode frame, and then wets the carbon cloth. Compared to conventional carbon felt electrodes, the carbon cloth electrode with flow channels in this application can significantly reduce the flow resistance of the electrolyte, reduce concentration polarization, and thus improve the voltage efficiency and energy efficiency of the flow battery.

[0007] In some embodiments, the carbon cloth in the carbon cloth electrode is arranged in an S-shape between the first flow channel and the second flow channel to form alternating parallel first electrode flow channels and second electrode flow channels.

[0008] In some embodiments, the carbon cloth in the carbon cloth electrode is a terry cloth with a loop length of 1mm to 1.5mm.

[0009] In some embodiments, the carbon cloth electrode has a dimension of 150 mm to 900 mm along the direction from the first flow channel to the second flow channel.

[0010] According to a second aspect of this application, a method for preparing an electrode-electrode frame composite assembly according to the first aspect of this application is provided, comprising the following steps: A carbon cloth and an electrode frame are provided, wherein the electrode frame is provided with a first flow channel and a second flow channel spaced apart from each other, the first flow channel having a plurality of first flow channel holes and the second flow channel having a plurality of second flow channel holes; The carbon is arranged between the first flow channel and the second flow channel, and the carbon cloth is bent and stacked to form the first electrode flow channel and the second electrode flow channel. The first electrode flow channel is connected to the first flow channel hole, and the second electrode flow channel is connected to the second flow channel hole.

[0011] In some embodiments, the carbon cloth is stacked in an S-shape between the first flow channel and the second flow channel to form alternating side-by-side first electrode flow channels and second electrode flow channels.

[0012] In some embodiments, the method for preparing the carbon cloth includes the following steps: Pre-oxidized yarn is made into yarn using ring spinning process; The yarn is made into a terry cloth with a terry weave structure using a terry weave process; The terry cloth is graphitized to obtain the carbon cloth.

[0013] In some embodiments, the twist of the ring spinning process is 280 twists / meter to 320 twists / meter.

[0014] In some embodiments, the graphitization process includes the following steps: The terry loops are arranged in a horizontal graphitization furnace and kept at 1800℃~2000℃ for 24h~72h.

[0015] According to a third aspect of this application, a flow battery is provided, including an electrode and electrode frame composite assembly according to the first aspect of this application, or an electrode and electrode frame composite assembly prepared by the preparation method of the second aspect of this application. Attached Figure Description

[0016] To better describe and illustrate the embodiments or examples provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments or examples, or the best mode of conduct of these applications as currently understood. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic diagram of the structure of an electrode and electrode frame composite assembly according to an embodiment of this application.

[0017] Explanation of reference numerals in the attached figures: 10. Electrode and electrode frame composite assembly; 11. Electrode frame; 111. First flow channel; 111a. First flow channel hole; 112. Second flow channel; 112a. Second flow channel hole; 12. Carbon cloth electrode; 121. First electrode flow channel; 122. Second electrode flow channel. Detailed Implementation

[0018] The technical solution of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] The "range" disclosed in this application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints. Any endpoint can be independently included or excluded, and they can be combined arbitrarily; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0" and "5" have been listed in this document; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, stating that a parameter is an integer ≥2 is equivalent to disclosing that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, stating that a parameter is an integer selected from "2~10" is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0020] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. The term "implementation" as used herein has a similar understanding.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] 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 technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0024] Traditional flow battery electrode materials typically use carbon felt, such as polyacrylonitrile-based carbon felt. This type of carbon felt electrode has high electrolyte flow resistance and low bulk density, leading to excessive concentration polarization in the stack, which in turn results in low voltage and energy efficiency of the flow battery. Furthermore, the large thickness of the carbon felt electrode results in a large overall stack size, making it difficult to achieve miniaturization of the stack structure. Reducing the thickness of the carbon felt electrode (e.g., to less than or equal to 2 mm) would severely reduce its bulk density due to limitations imposed by the needle-punching equipment, resulting in insufficient active sites and an inability to withstand high current densities, further contributing to low voltage and energy efficiency of the flow battery.

[0025] For this, please refer to Figure 1 One embodiment of this application provides an electrode and electrode frame composite assembly 10, which includes an electrode frame 11 and a carbon cloth electrode 12. The electrode frame 11 is provided with a first flow channel 111 and a second flow channel 112 spaced apart. The first flow channel 111 has a plurality of first flow channel holes 111a, and the second flow channel 112 has a plurality of second flow channel holes 112a. The carbon cloth electrode 12 is in close contact with the electrode frame 11 and is located between the first flow channel 111 and the second flow channel 112. The carbon cloth electrode 12 has a first electrode flow channel 121 communicating with the first flow channel hole 111a and a second electrode flow channel 122 communicating with the second flow channel hole 112a.

[0026] The electrode and electrode frame composite assembly 10 described above in this application comprises a carbon cloth electrode 12 disposed between a first flow channel 111 and a second flow channel 112. The carbon cloth electrode 12 has a first electrode flow channel 121 and a second electrode flow channel 122, with the first electrode flow channel 121 connected to a first flow channel hole 111a on the first flow channel 111, and the second electrode flow channel 122 connected to a second flow channel hole 112a on the second flow channel 112. With this structure, the electrolyte enters the first electrode flow channel 121 and / or the second electrode flow channel 122 of the carbon cloth electrode 12 from the first flow channel hole 111a and / or the second flow channel hole 112a of the electrode frame 11, and then wets the carbon cloth. Compared with conventional carbon felt electrodes, the carbon cloth electrode 12 with flow channels in this application can greatly reduce the flow resistance of the electrolyte, reduce concentration polarization, and thus improve the voltage efficiency and energy efficiency of the flow battery.

[0027] Furthermore, compared to traditional carbon felt electrodes, carbon cloth electrodes 12 can achieve a lower thickness while maintaining volume density, which is beneficial for reducing the overall size of the flow battery stack and realizing the miniaturization of the flow battery stack structure.

[0028] In some embodiments, the carbon cloth in the carbon cloth electrode 12 is arranged in an S-shape between the first flow channel 111 and the second flow channel 112, forming alternating parallel first electrode flow channels 121 and second electrode flow channels 122. That is, the carbon cloth is bent in an S-shape between the first flow channel 111 and the second flow channel 112 to form a first electrode flow channel 121 extending from the first flow channel 111 towards the second flow channel 112 and a second electrode flow channel 122 extending from the second flow channel 112 towards the first flow channel 111; furthermore, the first electrode flow channels 121 and 122 are alternately arranged side-by-side, with the opening of the first electrode flow channel 121 facing the first flow channel hole 111a and the opening of the second electrode flow channel 122 facing the second flow channel hole 112a. Thus, the alternating flow channel structure of the first electrode flow channels 121 and 122 is more conducive to reducing concentration polarization in the flow battery, thereby improving the voltage efficiency and energy efficiency of the flow battery.

[0029] In some embodiments, the carbon cloth in the carbon cloth electrode 12 is a terry cloth with a loop length of 1mm to 1.5mm. Using a terry cloth in the carbon cloth electrode 12 increases the contact area between the electrolyte and the carbon cloth electrode 12. The carbon cloth electrode 12 has more active sites, which helps reduce the activation polarization of the flow battery, thereby improving the voltage efficiency and energy efficiency of the flow battery.

[0030] Furthermore, the loop length of the terry cloth in the terry weave structure is controlled within the range of 1mm to 1.5mm. This ensures that the terry structure does not become loose due to excessive loop length, while simultaneously guaranteeing a large contact area between the carbon cloth electrode 12 and the electrolyte. Here, loop length refers to the effective fiber length of the protruding segment of the loop in the terry weave structure carbon cloth. Understandably, the loop length of the terry weave structure carbon cloth can be 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, or any value within the range formed by any two of the above values.

[0031] It should be noted that terry weaving is a unique structural feature in knitted fabrics, forming a fabric with loops through a specific weaving method. A terry structure is generally woven from two yarns: one for regular loops and the other for terry loops. Its structural units consist of ordinary loops and terry loops with elongated sinker arcs.

[0032] In some embodiments, the carbon cloth electrode 12 has a dimension of 150 mm to 900 mm along the direction from the first flow channel 111 to the second flow channel 112. Setting the dimension of the carbon cloth electrode 12 within the above range is beneficial in two ways: firstly, it allows the carbon cloth electrode 12 to have a larger volumetric density and a smaller electrolyte resistance; secondly, it allows the flow battery stack to have a smaller size, which is beneficial for miniaturizing the structure of the flow battery stack.

[0033] One embodiment of this application provides a method for preparing the above-described electrode and electrode frame composite assembly 10, the method comprising the following steps S100 and S200: Step S100: Provide carbon cloth and electrode frame 11, wherein the electrode frame 11 is provided with a first flow channel 111 and a second flow channel 112 spaced apart, the first flow channel 111 has a plurality of first flow channel holes 111a, and the second flow channel 112 has a plurality of second flow channel holes 112a.

[0034] Step S200: Arrange carbon between the first flow channel 111 and the second flow channel 112 of the electrode frame 11, bend and stack the carbon cloth to form the first electrode flow channel 121 and the second electrode flow channel 122, and connect the first electrode flow channel 121 with the first flow channel hole 111a, and connect the second electrode flow channel 122 with the second flow channel hole 112a.

[0035] The fabrication method described above involves placing a carbon cloth electrode 12 with a specific structure as described in this application between the first flow channel 111 and the second flow channel 112 of the electrode frame 11. The carbon cloth is then bent and stacked to form the first electrode flow channel 121 and the second electrode flow channel 122. The first electrode flow channel 121 is connected to the first flow channel hole 111a, and the second electrode flow channel 122 is connected to the second flow channel hole 112a. The electrode-electrode frame composite assembly 10 prepared by this method is beneficial for improving the voltage efficiency and energy efficiency of the flow battery.

[0036] In some embodiments, the carbon cloth is stacked in an S-shape between the first flow channel 111 and the second flow channel 112 to form alternating first electrode flow channels 121 and second electrode flow channels 122. This allows the first electrode flow channels 121 and the second electrode flow channels 122 to be arranged alternately side-by-side, with the opening of the first electrode flow channel 121 facing the first flow channel hole 111a and the opening of the second electrode flow channel 122 facing the second flow channel hole 112a, forming an alternating flow channel structure. This is more conducive to reducing concentration polarization in the flow battery, thereby improving the voltage efficiency and energy efficiency of the flow battery.

[0037] In some embodiments, the preparation method of carbon cloth includes the following steps: first, pre-oxidized yarn is made into yarn by ring spinning process; then, the yarn is made into terry cloth with terry weaving structure by terry weaving process; then, the terry cloth is graphitized to obtain carbon cloth.

[0038] Ring spinning can produce low-count yarn from pre-oxidized yarn, which is more conducive to reducing the flow resistance of the electrolyte and reducing concentration polarization of the battery. Using a terry weaving process to make the yarn into a terry cloth with a terry structure helps to increase the contact area between the carbon cloth electrode 12 and the electrolyte, as well as the number of active sites, which is more conducive to improving the voltage efficiency and energy efficiency of the flow battery.

[0039] Pre-oxidized fiber is an intermediate fiber made from polymer materials such as polyacrylonitrile, asphalt, and phenolic resin through a specific pre-oxidation treatment.

[0040] In some embodiments, the twist of the ring spinning process is 280 twists / meter to 320 twists / meter. Controlling the twist of the ring spinning process within this range is beneficial for the carbon cloth with a terry weave structure to simultaneously have low electrolyte flow resistance and good electrode support.

[0041] Understandably, the twist in ring spinning can be 280 twists / meter, 285 twists / meter, 290 twists / meter, 295 twists / meter, 300 twists / meter, 305 twists / meter, 310 twists / meter, 315 twists / meter, 320 twists / meter, or any value within the range formed by any two of the above values.

[0042] In some embodiments, the graphitization process includes the following steps: placing the loop fabric in a horizontal graphitization furnace and graphitizing it at a temperature of 1800℃~2000℃ for 24h~72h, while keeping the loop fabric in its natural state during the graphitization process.

[0043] The graphitization process conditions described above are beneficial for achieving a suitable density and degree of graphitization in the carbon cloth electrode 12, resulting in a better appearance and reducing the likelihood of wrinkles. Specifically, controlling the graphitization temperature within the aforementioned range is beneficial for achieving a suitable density and degree of graphitization in the carbon cloth electrode 12.

[0044] Understandably, the graphitization temperature can be 1800℃, 1820℃, 1850℃, 1880℃, 1900℃, 1920℃, 1950℃, 1980℃, 2000℃, or any value within the range formed by any two of the above values. The graphitization holding time can be 24h, 20h, 36h, 40h, 48h, 50h, 55h, 58h, 60h, 65h, 68h, 70h, 72h, or any value within the range formed by any two of the above values.

[0045] One embodiment of this application provides a flow battery (not shown), including the electrode and electrode frame composite assembly 10 described above, or the electrode and electrode frame composite assembly 10 prepared by the preparation method described above. By employing the electrode and electrode frame composite assembly 10 of this application, the flow battery of this application has high voltage efficiency and energy efficiency.

[0046] Understandably, the electrode and electrode frame composite assembly 10 of this application can form a single cell of a flow battery, and multiple single cells can form a flow battery stack. In addition to the stack, the flow battery may also include conventional auxiliary systems such as an electrolyte storage tank, a circulation pump, a temperature control system, a condition monitoring system, an electrical control system, and a safety protection system.

[0047] The present application will be further described below with reference to specific embodiments and comparative examples, but should not be construed as limiting the scope of protection of the present application.

[0048] Example 1: (1) The pre-oxidized yarn is spun into a low count yarn of 320 twists / meter using ring spinning process; the low count yarn is made into a looped fabric with looped weaving structure using looped weaving process, wherein the loop length is 1.5mm; the loops are arranged in a horizontal graphitization furnace and graphitized at 2000℃ for 24h, while keeping the looped fabric in a natural state during graphitization process to obtain carbon cloth.

[0049] (2) The carbon cloth is tightly placed between the first and second flow channels of the electrode frame, and the carbon cloth is bent in an S-shape between the first and second flow channels to form a carbon cloth electrode, thereby obtaining an electrode and electrode frame composite assembly. The carbon cloth electrode has a first electrode flow channel extending from the first flow channel to the second flow channel and a second electrode flow channel extending from the second flow channel to the first flow channel between the first and second flow channels; and the first and second electrode flow channels are alternately arranged side-by-side, with the opening of the first electrode flow channel facing the first flow channel hole and the opening of the second electrode flow channel facing the second flow channel hole. The dimension of the carbon cloth electrode along the direction from the first flow channel to the second flow channel is 500 mm.

[0050] Example 2: This embodiment is basically the same as embodiment 1, except that: the twist of the ring spinning process in step (1) is 280 twists / meter and the loop length is 1mm.

[0051] Example 3: This embodiment is basically the same as embodiment 1, except that the graphitization temperature in step (1) is 1800℃ and the holding time is 48h.

[0052] Comparative Example 1: A traditional polyacrylonitrile-based carbon felt was used instead of the carbon cloth in Example 1 as the electrode material. The carbon felt thickness was 1.5 mm.

[0053] Test method: (1) Single cell performance test At a current density of 160 mA / cm 2 Under the specified conditions, the coulombic efficiency (CE), voltage efficiency (VE), and energy efficiency (EE) of the single cell were tested according to "NB / T 42081-2016 Test Method for Single Cell Performance of Vanadium Redox Flow Battery". Wherein, energy efficiency = coulombic efficiency × voltage efficiency; that is, EE = CE × VE.

[0054] The composition of the positive electrode electrolyte used in the test was (by mass percentage): water (H2O): 52%, sulfuric acid (H2SO4): 20%, vanadium sulfate (V2(SO4)3): 16%, and vanadium oxysulfate (VOSO4): 12%.

[0055] The composition of the negative electrode electrolyte is as follows (by mass percentage): water (H2O): 52%, sulfuric acid (H2SO4): 20%, vanadium sulfate (V2(SO4)3): 16%, and vanadium oxysulfate (VOSO4): 12%.

[0056] The electrode and electrode frame composite assemblies of the above embodiments and comparative examples were assembled into vanadium redox flow battery single cells using conventional methods, and their battery performance was tested according to the single cell performance tests described above. The parameters and performance data of the single cells are shown in Table 1. " / " indicates that the cell was not present or was not tested.

[0057] Table 1

[0058] As shown in Table 1, the single cells using the electrode and electrode frame composite assemblies of the various embodiments of this application exhibit high voltage efficiency and energy efficiency. In Comparative Example 1, using conventional carbon felt as the electrode material results in a significant decrease in the voltage efficiency and energy efficiency of the corresponding single cell.

[0059] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A composite assembly of an electrode and an electrode frame, characterized in that, The device includes an electrode frame and a carbon cloth electrode. The electrode frame has a first flow channel and a second flow channel spaced apart. The first flow channel has a plurality of first flow channel holes, and the second flow channel has a plurality of second flow channel holes. The carbon cloth electrode is disposed on the electrode frame and located between the first flow channel and the second flow channel. The carbon cloth electrode has a first electrode flow channel communicating with the first flow channel holes and a second electrode flow channel communicating with the second flow channel holes. The carbon cloth in the carbon cloth electrode is arranged in an S-shape between the first flow channel and the second flow channel to form alternating and parallel first electrode flow channels and second electrode flow channels. The carbon cloth in the carbon cloth electrode is a terry cloth with a loop length of 1mm to 1.5mm.

2. The electrode and electrode frame composite assembly according to claim 1, characterized in that, The carbon cloth electrode has a dimension of 150mm to 900mm along the direction from the first flow channel to the second flow channel.

3. A method for preparing the electrode and electrode frame composite assembly as described in claim 1 or 2, characterized in that, Includes the following steps: A carbon cloth and an electrode frame are provided, wherein the electrode frame is provided with a first flow channel and a second flow channel spaced apart from each other, the first flow channel having a plurality of first flow channel holes and the second flow channel having a plurality of second flow channel holes; The carbon is arranged between the first flow channel and the second flow channel, so that the carbon cloth is stacked in an S-shape between the first flow channel and the second flow channel to form an alternately arranged first electrode flow channel and second electrode flow channel, and the first electrode flow channel is connected to the first flow channel hole, and the second electrode flow channel is connected to the second flow channel hole.

4. The method for preparing the electrode and electrode frame composite assembly according to claim 3, characterized in that, The preparation method of the carbon cloth includes the following steps: Pre-oxidized yarn is made into yarn using ring spinning process; The yarn is made into a terry cloth with a terry weave structure using a terry weave process; The terry cloth is graphitized to obtain the carbon cloth.

5. The method for preparing the electrode and electrode frame composite assembly according to claim 4, characterized in that, The twist rate of the ring spinning process is 280 twists / meter to 320 twists / meter.

6. The method for preparing the electrode and electrode frame composite assembly according to claim 4, characterized in that, The graphitization process includes the following steps: The terry loops are arranged in a horizontal graphitization furnace and kept at 1800℃~2000℃ for 24h~72h.

7. A flow battery, characterized in that, It includes the electrode and electrode frame composite assembly according to any one of claims 1 to 2, or the electrode and electrode frame composite assembly prepared by the preparation method according to any one of claims 3 to 6.

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