Carbon cloth texturing method for improving electrical properties of carbon cloth

Abstract

The invention relates to the technical field of carbon cloth texturing, and particularly discloses a carbon cloth texturing method for improving the electrical property of carbon cloth, which aims at improving the electrical property of the carbon cloth in an iron-chromium flow battery by simulating related structural phases and organizational structures, obtains an optimal organizational scheme by designing the organizational structures and changing the structural phases, and improves the electrical property of the carbon cloth in the iron-chromium flow battery. And the produced carbon cloth structure is used for verifying the performance of the iron-chromium flow battery. According to the structure obtained through simulation, grooves between warp and weft interweaving points and floating lines are increased, so that the contact area of the electrolyte and the carbon cloth is increased, the charge transfer resistance of defect sites of the carbon cloth is reduced, the electron conductivity of the electrolyte in the flow battery is improved, the mechanical performance of the carbon cloth in the electrolyte is improved, and the fluid resistance is reduced. According to the method, factors such as a tissue structure, warp and weft yarns and weaving parameters of the carbon cloth are limited through a simulation rule, the textured carbon cloth is verified, and it is found that the carbon cloth can effectively improve the electrical performance in a battery after verification.

Description

Technical Field

[0001] The invention relates to the technical field of carbon cloth texturing, and in particular to a carbon cloth texturing method for improving the electrical properties of the carbon cloth. Background Art

[0002] Iron-chromium flow batteries have good industrialization and market application prospects in the emerging field of flow battery energy storage due to their lower cost and higher environmental friendliness. The research on iron-chromium flow batteries mainly focuses on three key materials, including electrode materials, electrolytes and ion exchange membranes.

[0003] The mainstream electrode materials are carbon-based materials, such as carbon fiber felt, carbon cloth, carbon paper, etc. The carbon cloth fibers are arranged relatively orderly and the pores are widely distributed. Compared with carbon paper and carbon fiber felt, carbon cloth electrodes have larger pore sizes, lower tortuosity, higher permeability, lower flow resistance and lower pumping losses, so carbon cloth is a more widely used electrode material. At present, most of the research on electrode materials is on the modification of electrode materials, such as oxidation modification and catalyst modification, with the aim of improving the hydrophilicity and electrochemical activity of the electrode to improve battery performance. However, there are few studies on the structure of carbon cloth. According to the structural characteristics of carbon cloth electrodes, the arrangement and number of interlacing points between the warp and weft yarns will affect the charge transfer resistance and electronic conductivity of the carbon cloth after carbonization. The porosity, pore size, permeability and other factors of the carbon cloth also affect the battery performance. Therefore, studying the factors affecting the structure of carbon cloth on battery performance is of profound significance for in-depth exploration of electrode materials and accelerating the industrialization of iron-chromium flow batteries. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a carbon cloth texturing method for improving the electrical performance of carbon cloth. By simulating the relevant structural phases and organizational structures, the electrical performance of carbon cloth in iron-chromium flow batteries is improved. The preferred organizational scheme is obtained by designing the organizational structure and changing the structural phase, and the carbon cloth organization is produced for iron-chromium flow battery performance verification. In the organization obtained by simulation in the present invention, the grooves between the warp and weft yarn interlacing points and the floating long lines are increased, thereby increasing the contact area between the electrolyte and the carbon cloth, reducing the charge transfer resistance of the carbon cloth defect sites, improving the electronic conductivity of the electrolyte in the flow battery, improving the mechanical properties of the carbon cloth in the electrolyte, reducing the fluid resistance, and finally improving the electrical performance of the carbon cloth in the battery. The present invention defines the organizational structure, weaving parameters and other aspects of the organization, and the factors affecting the change of the fabric organizational structure include the fineness of the warp and weft yarns, the twist of the warp and weft yarns, the tightness of the weaving, etc., solving the problems mentioned in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: A carbon cloth texturing method for improving the electrical properties of carbon cloth, comprising the following steps:

[0006] S1. Carry out simulation based on the performance of carbon cloth;

[0007] S2. Design the organizational structure according to the simulation results and draw the organizational design diagram;

[0008] S3. Based on the tissue design diagram, the carbon cloth texture is completed through a loom using warp and weft yarns and weaving parameters.

[0009] Preferably, in step S1, the properties of the carbon cloth include the electronic conductivity, charge transfer resistance, liquid flow resistance and surface area of ​​the carbon cloth.

[0010] Preferably, in step S1, the simulation includes the following:

[0011] S11, establish a geometric model based on the basic organization, and divide the grid into a calculation model;

[0012] The basic weaves are plain weave, twill weave and satin weave; geometric models are established according to the structural phases and warp and weft interlacing characteristics of the three basic weaves, and mesh division is performed to form a simulation calculation model;

[0013] S12, define physical fields and material properties, set boundary conditions, simulation parameters and the size of the workspace;

[0014] The set physical field is a multi-physics coupling field of fluid, structure, and current. The set boundary conditions and simulation parameters include but are not limited to fluid resistance, pressure drop, current density, and liquid flow pattern;

[0015] S13, changing the organizational structure phase conditions, solving the model and obtaining the simulation rules;

[0016] The changed structural phase condition refers to changing the arrangement and number of interlacing points under the interlacing conditions of the warp and weft yarns of the basic organization; by comparing multiple groups of simulation data, the rules of the structural phase, the arrangement and number of interlacing points of the warp and weft yarns are obtained.

[0017] Preferably, in step S2, the simulation rules are specifically: 1) the more the interweaving points of the warp and weft yarns increase, the more parallel connections of the potential points on the carbon cloth are formed, the smaller the charge transfer resistance is, the greater the electron conductivity is, and the better the electrical properties of the carbon cloth are; 2) the more gullies / grooves there are between the interweaving points and the floating lines, the greater the contact area between the electrolyte and the carbon cloth is, the lower the fluid resistance of the electrolyte is, the greater the surface area of ​​the carbon cloth is, and the electrolyte reaction sites are randomly increased after carbonization activation, thereby improving the electrical performance of the carbon cloth in the battery.

[0018] Through simulation calculation of the phase change of the basic organization and related structures, it is concluded that the more interlaced convex points are appropriately increased, the more parallel connections are formed by the potential points on the carbon cloth, the smaller the charge transfer resistance, the greater the electronic conductivity, and the better the electrical properties of the carbon cloth. At the same time, the more interlaced points are increased, the more forces act on the inside of the carbon cloth, and the mechanical properties of the carbon cloth against the outside world are increased. Therefore, the organization designed by the present invention increases the number of interlaced points by 40-150 organization points in a single organization cycle compared to the basic organization.

[0019] Through simulation calculations of the phase changes of the basic organization and related structures, it is concluded that the more grooves there are between the interlacing points and the floating lines, the larger the contact area between the electrolyte and the carbon cloth, and the better the electrical performance of the carbon cloth. When carbon cloth is used in iron-chromium flow batteries, different reaction sites will be randomly assigned to the carbon cloth during the carbonization stage. The larger the contact area between the electrolyte and the carbon cloth, the more contact reaction sites, and the better the battery performance.

[0020] Preferably, in step S2, through simulation calculation of the phase changes of the basic tissue and related structures, it is concluded that an appropriate increase in interlacing points and an increase in gullies within the tissue will both improve battery performance, but the factors are mutually restrained. An increase in gullies in a single tissue will lead to a decrease in interlacing points. Therefore, the tissue structure designed by the present invention is formed by a ground tissue and a flower tissue. The ground tissue is a plain weave, and the flower tissue is a jacquard weave, which adopts a knotless weaving method; the tissue increases the interlacing points of the warp and weft yarns through the ground tissue, and increases the gullies within the tissue through the flower tissue. Different from the basic tissues such as plain weave and twill in the market, the tissue structure of the present invention has both structural innovation and the ability to improve battery performance.

[0021] Preferably, in step S3, the warp and weft yarn parameters include warp and weft yarn fineness, yarn twist, parallel thread number and double twist; the weaving parameters include the spring position affecting the tension of the upper machine, the opening time and the weft beating time.

[0022] Preferably, the fineness of the warp and weft yarns ranges from 23.6 to 39.4 tex.

[0023] Preferably, the yarn twist range is 430T / m-617T / m. The smaller the single yarn twist, the looser the yarn and the smaller the hardness. At this time, the grooves formed by the warp and weft yarns between the fabrics are obvious, and the permeability of the treated carbon cloth to the electrolyte is also higher.

[0024] Preferably, the number of parallel lines ranges from 2 to 4.

[0025] Preferably, the twisting degree ranges from 140T / m to 280T / m. Within this range, the smaller the twisting degree of the strands, the more dispersed the inlay between the single yarns, and the higher the weaving efficiency under the same weaving parameter conditions. At the same time, the permeability and fluidity of the electrolyte are higher.

[0026] Preferably, the spring position that affects the upper machine tension in the weaving parameter is spring 1-5 point position, and the upper machine tension increases successively. The fewer the warp and weft yarn interlacing points, the smaller the choice of the upper machine tension.

[0027] Preferably, the opening time and the beating time in the weaving parameters are changed according to the increase of the interlacing points of the tissue, and the change range is 5°-25° of the conjugate cam axis. Specifically, the opening time is 305°-325°; the beating time is 315°-355°.

[0028] The beneficial effects of the present invention are:

[0029] 1) The method of the present invention proposes a carbon cloth texturing method for improving the electrical properties of carbon cloth, and specifically proposes conditions such as the arrangement of warp and weft yarn interlacing points, warp and weft yarn specifications and weaving parameters for forming the organization. The organization can reduce the fluid resistance of the electrolyte in the flow battery, improve the permeability of the carbon cloth electrode, reduce the charge transfer resistance between the interlacing points in the carbon cloth, improve the electronic conductivity, and improve the electrical properties of the carbon cloth electrode.

[0030] 2) The method of the present invention enriches the carbon cloth organizational structure and texturing method currently on the market, optimizes the physical and electrical properties of carbon cloth in liquid flow batteries, makes up for the current research shortcomings in the field of iron-chromium liquid flow batteries in terms of battery materials, increases the research on carbon cloth structure in this field, and helps to promote the development of iron-chromium liquid flow batteries and accelerate the industrialization of iron-chromium liquid flow batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A partially captured schematic diagram of a simulation model in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of 20x electron microscope observation of the tissue of Example 3 of the present invention;

[0033] Figure 3 This is a schematic diagram of 50 times electron microscope observation of the tissue of Example 3 of the present invention;

[0034] Figure 4 This is a schematic diagram of 50 times electron microscope observation of the tissue of Example 4 of the present invention;

[0035] Figure 5 This is a schematic diagram of the organization of Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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. 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.

[0037] Example 1

[0038] Carry out simulation with the performance of carbon cloth as the target;

[0039] The simulation includes the following:

[0040] 1. Use the basic organization to establish a geometric model, and divide the mesh into a calculation model, such as Figure 1 As shown;

[0041] The basic weaves are plain weave, twill weave and satin weave. The geometric models are established according to the structural phases and warp and weft interweaving characteristics of the three basic weaves, and the grid division is performed to form a simulation calculation model.

[0042] In this embodiment, the geometric model is established based on the plain weave in the basic structure.

[0043] 2. Define the physical fields and material properties, set boundary conditions, simulation parameters and the size of the workspace.

[0044] The set physical field is a multi-physical field coupling field of fluid, structure, and current. The set boundary conditions and simulation parameters include but are not limited to fluid resistance, pressure drop, current density, and liquid flow pattern.

[0045] 3. Change the organizational structure phase conditions, solve the model and obtain the simulation rules;

[0046] The changed structural phase condition refers to changing the arrangement and number of interlacing points under the interlacing conditions of the warp and weft yarns of the basic organization; by comparing multiple groups of simulation data, the rules of the structural phase, the arrangement and number of interlacing points of the warp and weft yarns are obtained.

[0047] In this embodiment, 20, 40, and 60 warp and weft interlacing points are randomly added to the model, and 20, 40, and 60 interlacing points are reduced, respectively. The above steps are repeated, and the simulation rules are statistically compared through data, as shown in Table 1.

[0048] Table 1 Data of various simulation changes in Example 1

[0049] Interweaving point changes +20 +40 +60 -20 -40 -60 Charge transfer resistance(Ω) -36.8％ -50.1％ -70.5％ +11.1％ +26.7％ +31.2％ Electronic conductivity (S / m) +89.5 +100.4％ +293％ -9.9％ -21.1％ -23.8％ Energy efficiency (%) +3.8％ +5.1％ +7.6％ -1.3％ -2.5％ -5.2％

[0050] Example 2

[0051] Carry out simulation with the performance of carbon cloth as the target;

[0052] The simulation includes the following:

[0053] 1. Establish geometric model based on basic organization, and divide the grid into computational models;

[0054] The basic weaves are plain weave, twill weave and satin weave. The geometric models are established according to the structural phases and warp and weft interweaving characteristics of the three basic weaves, and the grid division is performed to form a simulation calculation model.

[0055] In this embodiment, the geometric model is established based on the basic structure 2 / 1 twill structure.

[0056] 2. Define the physical fields and material properties, set boundary conditions, simulation parameters and the size of the workspace.

[0057] The set physical field is a multi-physical field coupling field of fluid, structure, and current. The set boundary conditions and simulation parameters include but are not limited to fluid resistance, pressure drop, current density, and liquid flow pattern.

[0058] 3. Change the organizational structure phase conditions, solve the model and obtain the simulation rules;

[0059] The changed structural phase condition refers to changing the arrangement and number of interlacing points under the interlacing conditions of the warp and weft yarns of the basic organization; by comparing multiple groups of simulation data, the rules of the structural phase, the arrangement and number of interlacing points of the warp and weft yarns are obtained.

[0060] In this embodiment, the number of gullies is randomly increased by 5, 10, and 15 in the model, and the number of gullies is randomly reduced by 5, 10, and 15. The model size is in the centimeter level, and the gully size is in the millimeter level. Repeat the above steps, and compare the data to obtain the statistical simulation rules, as shown in Table 2.

[0061] Table 2 Data of various simulation changes in Example 2

[0062] Changes in the number of gullies +5 +10 +15 -5 -10 -15 Fluid resistance (F) -10.0％ -18.1％ -40.4％ +8.2％ +20.6％ +38.5％ <![CDATA[Reaction area (mm 2 )]]> +0.75％ +1.5％ +2.25％ -0.75％ -1.5％ -2.25％ Energy efficiency (%) +1.3％ +3.6％ +5.6％ -2.2％ -4.5％ -7.9％

[0063] Comprehensive analysis of Table 1 and Table 2 shows that the increase in the number of warp and weft interlacing points and the number of gullies will improve battery performance. The increase in the number of interlacing points will improve the electronic conductivity of the carbon cloth. The increase in the number of gullies will reduce the fluid resistance of the electrolyte, increase the surface area of ​​the carbon cloth, and randomly increase the electrolyte reaction sites after carbonization activation. Therefore, the organization design idea of ​​the present invention is to increase the number of warp and weft interlacing points through the ground organization, and increase the gullies between the interlacing points and the floating lines through the flower organization.

[0064] Example 3

[0065] According to the rules obtained by simulation, the organization of the present invention is designed. The preferred warp and weft yarn specifications are: single yarn fineness 36.9tex, single yarn twist 461T / m, parallel yarn number 4, double twist twist 270T / m. According to the organization and production method of the present invention, weaving is carried out, and the parameters during weaving are: spring position 2 of the upper machine tension, opening time 305°-320°, and weft beating time 315°-350°. Organization as Figure 2 and Figure 3 As shown, the performance data of the carbon cloth produced in Example 3 after treatment in a small experimental battery are shown in Table 3.

[0066] Table 3 Battery performance data of each embodiment and comparative example

[0067]

[0068] Example 4

[0069] According to the rules obtained by simulation, the organization of the present invention is designed. The preferred warp and weft yarn specifications are: single yarn fineness 28.1tex, single yarn twist 566T / m, parallel yarn number 4, double twist twist 330T / m. According to the organization and production method of the present invention, weaving is carried out, and the parameters during weaving are: spring position 2 of the upper machine tension, opening time 310°-325°, and weft beating time 320°-355°. Organization as Figure 4 As shown, the performance data of the carbon cloth of Example 4 after treatment in the small test battery is shown in Table 3.

[0070] Comparative Example 1

[0071] The plain weave in the basic organization is selected for production. The preferred warp and weft yarn specifications are: single yarn fineness 59tex, single yarn twist 365T / m, parallel yarn number 2, double twist twist 290T / m. The parameters during weaving are: spring position 1 of the upper machine tension, opening time 290°-305°, and weft beating time 300°-335°. Organization such as Figure 5 As shown, the performance data of the carbon cloth of Comparative Example 1 in the small test battery after treatment is shown in Table 3.

[0072] The simulation process is an ideal test condition. The organization designed according to the simulation rules is put into actual production verification. The effect is shown in the performance data of Example 3 and Example 4 and Comparative Example 1 in Table 3.

[0073] Comprehensive analysis of Table 1 shows that among Examples 3-4, the carbon cloth fabric woven using the tissue and production method of the present invention has better battery performance in small tests after treatment than the plain weave of Comparative Example 1.

[0074] Combined with the analysis of the accompanying drawings and Tables 1-3, the organization of the present invention has more grooves between the interweaving points and the floating lines than the plain weave of the basic organization, so the contact area between the electrolyte and the carbon cloth is increased; the organization of the present invention has more convex points, and more parallel potentials are formed on the carbon cloth, so the charge transfer resistance is smaller, and the electronic conductivity of the carbon cloth is greater; the more convex points of the present invention, the more mechanical force reaction components of the electrolyte acting on the carbon cloth, and the greater the impact resistance of the carbon cloth. Comprehensive analysis shows that the carbon cloth formed by the organization of the present invention can better improve battery performance.

[0075] In summary, the organization and texturing method proposed in the present invention can improve the electrical performance of carbon cloth in batteries. The organization designed by the present invention is affected by factors including yarn specifications, organization design, etc.; the texturing method described in the present invention is affected by factors including organization design, weaving parameters, etc.

[0076] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A carbon cloth texturing method for improving the electrical properties of carbon cloth, characterized in that: The steps include: S1. Carry out simulation based on the performance of carbon cloth; S2. Design the organizational structure according to the simulation results and draw the organizational design diagram; S3. Based on the tissue design diagram, the carbon cloth texture is completed through a loom using warp and weft yarns and weaving parameters.

2. The carbon cloth texturing method for improving the electrical properties of carbon cloth according to claim 1, characterized in that: In step S1 , the properties of the carbon cloth include the electronic conductivity, charge transfer resistance, liquid flow resistance and surface area of ​​the carbon cloth.

3. The carbon cloth texturing method for improving the electrical properties of carbon cloth according to claim 1, characterized in that: In step S1, the simulation includes the following: S11, establish a geometric model based on the basic organization, and divide the grid into a calculation model; The basic weaves are plain weave, twill weave and satin weave; geometric models are established according to the structural phases and warp and weft interlacing characteristics of the three basic weaves, and mesh division is performed to form a simulation calculation model; S12, define physical fields and material properties, set boundary conditions, simulation parameters and the size of the workspace; The set physical field is a multi-physics coupling field of fluid, structure, and current. The set boundary conditions and simulation parameters include but are not limited to fluid resistance, pressure drop, current density, and liquid flow pattern; S13, changing the organizational structure phase conditions, solving the model and obtaining the simulation rules; The changed structural phase condition refers to changing the arrangement and number of interlacing points under the interlacing conditions of the warp and weft yarns of the basic structure; By comparing multiple sets of simulation data, the rules of structural phase, arrangement of warp and weft interlacing points and changes in quantity are obtained.

4. The carbon cloth texturing method for improving the electrical performance of carbon cloth according to claim 1, characterized in that: In step S2, the simulation rules are as follows: 1) As the number of interweaving points of the warp and weft yarns increases, more parallel connections are formed at the potential points on the carbon cloth, the smaller the charge transfer resistance is, the greater the electron conductivity is, and the better the electrical properties of the carbon cloth are; 2) As the number of gullies / grooves between the interweaving points and the floating lines increases, the contact area between the electrolyte and the carbon cloth increases, which reduces the fluid resistance of the electrolyte and increases the surface area of ​​the carbon cloth. After carbonization activation, the electrolyte reaction sites are randomly increased, thereby improving the electrical performance of the carbon cloth in the battery.

5. The carbon cloth texturing method for improving the electrical properties of carbon cloth according to claim 1, characterized in that: In step S2, the weave structure is formed by a ground weave and a pattern weave. The ground weave is a plain weave, and the pattern weave is a jacquard weave, using a knotless weaving method. The weave increases the warp and weft interlacing points through the ground weave, and increases the internal grooves through the pattern weave.

6. The carbon cloth texturing method for improving the electrical properties of carbon cloth according to claim 1, characterized in that: In step S3, the warp and weft yarn parameters include the warp and weft yarn fineness, yarn twist, parallel thread number and double twist; the weaving parameters include the spring position affecting the tension of the upper machine, the opening time and the beating time.

7. The carbon cloth texturing method for improving the electrical properties of carbon cloth according to claim 6, characterized in that: The fineness of the warp and weft yarns ranges from 23.6 to 39.4 tex; the twist of the yarn ranges from 430 T / m to 617 T / m; the number of parallel yarns ranges from 2 to 4; and the twist ranges from 140 T / m to 280 T / m.

8. The carbon cloth texturing method for improving the electrical performance of carbon cloth according to claim 6, characterized in that: The spring position affecting the tension of the upper machine is spring 1-5 points; the opening time is 305°-325°; and the beating time is 315°-355°.

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