High-efficiency vanadium battery electrode material manufacturing process

Abstract

The invention discloses a high-efficiency vanadium battery electrode material manufacturing process, which comprises the following steps of: spinning yarns of which the protofilament fineness is 1.44 Dtx, the limit oxygen index is 42-44%, the breaking strength is greater than 1.96 cn / dtex and the crimpness is 40-48 pieces / 10cm, dipping, drying and blending 10 / 2 strands of male yarns, and carbonizing by adopting a continuous carbonization furnace structure, thereby obtaining the high-efficiency vanadium battery electrode material. Activating by adopting an air activating furnace structure; according to the invention, an innovative woven fabric structure material is adopted to make the electrode, and the energy efficiency of the prepared carbon cloth under high current density is obviously higher than that of a carbon felt and a common carbon cloth through special specifications of pre-oxidized fibers, spinning specifications, a woven structure, a carbonization process and an activation process, so that the utilization efficiency of an electrolyte can be improved, and the system cost can be reduced.

Description

Technical Field

[0001] This invention relates to a manufacturing process for a highly reactive electrode material for flow batteries, which can significantly improve the reaction efficiency of flow batteries and increase the power density of the batteries. The application belongs to the field of flow battery applications. Background Technology

[0002] Given the gradual depletion of traditional fossil fuels and the pollution they cause, the utilization of new clean and renewable energy sources (wind power, solar power, etc.) has become a new research focus. However, these new energy sources are characterized by intermittency and instability, making efficient and safe storage a new challenge. Flow batteries, due to their high safety performance, convenient capacity expansion, long lifespan, low cost, and environmental friendliness, have become an important force in the field of electrochemical energy storage.

[0003] Vanadium redox flow battery (VRFB), as the most mature technology in the field of flow batteries, has gained widespread market recognition due to its early research and development, complete industrial support, and high current density compared to other flow batteries. It is also one of the earliest flow batteries to be used on a large scale. However, as vanadium is a rare metal, its raw material cost is currently the main factor limiting the development of VRFB. Therefore, developing electrodes with higher specific surface area and reactive sites, thereby increasing the total amount of reactive materials and energy efficiency, to improve the utilization rate of electrolyte and reduce the amount of vanadium electrolyte used, is of great significance for reducing system costs.

[0004] During the charging process, the vanadium redox flow battery uses a circulation pump to push the used electrolyte back to the electrodes, where it is recharged and returned to the storage tank. Therefore, the flow battery will become a powerful support for the large-scale deployment of wind and solar energy. The main core components of the flow battery are electrodes, ion exchange membranes, and electrolytes. Among them, the electrode surface is the site where the reactive materials undergo oxidation and reduction. Its performance directly affects the rate and total amount of reaction of the reactive materials, and thus plays a crucial role in the overall performance of the battery.

[0005] Traditional flow batteries employ a felt structure followed by carbonization, graphitization, and activation. However, the bonding structure suffers from unevenness during the needle-punching process, and the felt material cannot be made thin, resulting in low electrolyte utilization efficiency and dead zones where the electrolyte cannot reach the battery during operation. Conversely, making the electrode felt too thick presents unresolved ohmic polarization issues. Therefore, developing uniform and thin electrode materials is crucial for solving these problems. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the technical solution provided by the present invention is: a high-efficiency vanadium battery electrode material manufacturing process, comprising the following steps:

[0007] (1) Pre-oxidized yarn: The yarn with a fineness of 1.44Dtx, a limiting oxygen index of 42%-44%, a breaking strength greater than 1.96cn / dtex, and a crimp of 40-48 curls / 10cm is selected for spinning.

[0008] (2) Spinning: Select 10 / 2 count yarn. After the yarn is opened, loosened, drawn and twisted into 10 count yarn on the spinning equipment, the yarn is immersed in a phenolic resin solution with a concentration of 3%-8% for immersion. Then, it is dried at 120-140℃ for 15-35 minutes. Then, the 10 count yarn is combined into two strands to form 10 / 2 count yarn with a twist of 200-220 twists.

[0009] (3) Weaving: Weave 10 / 2 strands of yarn into fabric with a warp and weft density of 100 x 80 threads / 10cm and a carbon cloth weight of 375g / ㎡.

[0010] (4) Carbonization: A continuous carbonization furnace structure is adopted. The carbonization temperature of the carbonization furnace is 300-1200℃ and the temperature is increased in stages. The carbonization speed is 0.5-0.8m / min. During carbonization, the positive pressure inside the furnace is maintained between 100-150pa. During carbonization, pure oxygen gas needs to be introduced into the furnace at a temperature between 350-600℃. In the area from the inlet of the carbonization furnace to 600℃, the oxygen content is guaranteed to be 0.11%-0.15%, and at the outlet, the oxygen content is between 300-800PPM. After carbonization, the weight loss rate of the material is between 45-50%, and the shrinkage rate is between 60-75%.

[0011] (5) Activation: An air activation furnace structure is adopted, and the carbonized material moves at a speed of 1-1.5 m / min in the activation furnace; air is circulated in the furnace chamber at a flow rate of 5-10 m³ / min. 3 / h; After activation, the weight loss rate of the carbon fiber cloth is between 5% and 10%.

[0012] The advantages of this invention compared to existing technologies are as follows: This invention uses an innovative woven fabric structure material as the electrode. Through special specifications of pre-oxidized yarn, spinning specifications, weaving structure, carbonization process, and activation process, the energy efficiency of the carbon cloth produced under high current density is significantly higher than that of carbon felt and ordinary carbon cloth, which can improve electrolyte utilization efficiency and reduce system cost. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the spinning process in the manufacturing process of a high-efficiency vanadium battery electrode material according to the present invention.

[0014] Figure 2 This is a schematic diagram of the all-vanadium redox flow battery electrode test structure in the manufacturing process of a high-efficiency vanadium battery electrode material according to the present invention.

[0015] Figure 3 This is a schematic diagram illustrating the test results during the manufacturing process of a high-efficiency vanadium battery electrode material according to the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0017] Example:

[0018] A manufacturing process for a high-efficiency vanadium battery electrode material, characterized by comprising the following steps:

[0019] (1) Selection of pre-oxidized yarn: Traditional electrode felt uses SGL, 2.2Dtx, limiting oxygen index of 40%-42%, and breaking strength of 3.21cn / dtex for needle-punched felt body; In this embodiment, yarn with a fineness of 1.44Dtx, limiting oxygen index of 42%-44%, breaking strength greater than 1.96cn / dtex, and crimp of 40-48 curls / 10cm is selected for spinning.

[0020] (2) Spinning: Select 10 / 2 count yarn with a primary twist of 300-320 twists / m and a ply twist of 200-220 twists. The tensile breaking strength of the yarn is between 12-18N. After the yarn is opened, loosened, drawn, and twisted into 10 count yarn on the spinning equipment, the yarn is immersed in a phenolic resin solution with a concentration of 3%-8% for immersion. Then, it is dried at 120-140℃ for 15-35 minutes. Then, the 10 count yarn is combined into two plies to form 10 / 2 count yarn with a ply twist of 200-220 twists.

[0021] (3) Weaving: The 10 / 2 strand yarn is woven into fabric with a warp and weft density of 100 x 80 threads / 10cm and a carbon fiber weight of 375g / m². 2 During the weaving process, with a warp diameter of 60mm, the counterweight bar wall length is 50mm, the counterweight added to the warp roll is 7.5-10kg, the tension applied to the weft weaving monofilament is 0.5-1.5N, and the weaving speed is 1.8-2.5m / hour.

[0022] (4) Carbonization: The carbonization furnace adopts a continuous carbonization furnace structure. The total length of the carbonization furnace is 30m, and the heating zone is 12m. Nitrogen protection is used for carbonization. The carbonization temperature in the furnace is 300-1200℃, and the temperature is increased in stages within the 12m zone. The carbonization rate is 0.5-0.8m / min. During carbonization, the positive pressure inside the furnace is maintained between 100-150pa. Pure oxygen gas needs to be introduced into the furnace at a temperature between 350-600℃. In the area between the furnace inlet and 600℃, the oxygen content is maintained at 0.11%-0.15%, and at the outlet, the oxygen content is between 300-800PPM. After carbonization, the weight loss rate of the material is between 45-50%, and the shrinkage rate is between 60-75%.

[0023] (5) Activation: In an air activation furnace with a length of 12m and a width of 1m, and a furnace chamber size of 12x1x0.2m, the heating temperature is between 450-600℃. The material after graphitization travels at a speed of 1-1.5m / min within the activation furnace. Air is circulated within the furnace chamber at a flow rate of 5-10m³ / min. 3 / h. After activation, the weight loss rate of the carbon fiber cloth is between 5% and 10%.

[0024] I. Experimental Verification

[0025] After the carbon cloth is processed in this invention, the activated electrode cloth is cleaned in deionized water. Then, using the method described in the standard "NBT42082-2016 Test Method for Vanadium Redox Flow Battery Electrodes," the electrode material is installed onto the attached... Figure 2 In the fuel cell stack shown, then connect the piping and charging / discharging system;

[0026] Using cyclic voltammetry in a vanadium battery stack, with a maximum electrolyte flow rate of 10 m / s and a charging voltage of 1.6 V, patented carbon cloth was tested for 20 cycles according to standard methods. Comparative tests were conducted on ordinary carbon cloth and patented carbon cloth using the same experimental method. The test results are attached. Figure 3 As shown, the test results indicate that the patented carbon cloth has a significantly higher energy efficiency than carbon felt and ordinary carbon cloth at high current densities.

[0027] The present invention and its embodiments have been described above. This description is not restrictive. In short, if a person skilled in the art is inspired by this description and designs a similar structure and embodiment without departing from the spirit of the present invention, such design should fall within the protection scope of the present invention.

Claims

1. A manufacturing process for a high-efficiency vanadium battery electrode material, characterized in that, Includes the following steps: (1) Pre-oxidized yarn: The yarn with a fineness of 1.44Dtx, a limiting oxygen index of 42%-44%, a breaking strength greater than 1.96cn / dtex, and a crimp of 40-48 curls / 10cm is selected for spinning. (2) Spinning: Select 10 / 2 count yarn. After the yarn is opened, loosened, drawn and twisted into 10 count yarn on the spinning equipment, the yarn is immersed in a phenolic resin solution with a concentration of 3%-8% for immersion. Then, it is dried at 120-140℃ for 15-35 minutes. Then, the 10 count yarn is combined into two strands to form 10 / 2 count yarn with a twist of 200-220 twists. (3) Weaving: Weave 10 / 2 strands of yarn into fabric with a warp and weft density of 100 x 80 strands / 10cm and a carbon cloth weight of 375g / ㎡. (4) Carbonization: A continuous carbonization furnace structure is adopted. The carbonization temperature of the carbonization furnace is 300-1200℃ and the temperature is increased in stages. The carbonization speed is 0.5-0.8m / min. During carbonization, the positive pressure inside the furnace is maintained between 100-150pa. During carbonization, pure oxygen gas needs to be introduced into the furnace at a temperature between 350-600℃. In the area from the inlet of the carbonization furnace to 600℃, the oxygen content is guaranteed to be 0.11%-0.15%, and at the outlet, the oxygen content is between 300-800PPM. After carbonization, the weight loss rate of the material is between 45-50%, and the shrinkage rate is between 60-75%. (5) Activation: An air activation furnace structure is adopted, and the carbonized material travels at a speed of 1-1.5 m / min in the activation furnace; Air is circulated within the furnace chamber of the air activation furnace at a flow rate of 5-10 m³ / h. 3 / h; After activation, the weight loss rate of the carbon fiber cloth is between 5% and 10%.

2. The manufacturing process for a high-efficiency vanadium battery electrode material according to claim 1, characterized in that, In step (2), the yarn specifications are as follows: its primary twist is 300-320 twists / m, its ply twist is 200-220 twists, and its tensile breaking strength is between 12-18N.

3. The manufacturing process for a high-efficiency vanadium battery electrode material according to claim 1, characterized in that, In the weaving process of step (3), the diameter of the textile warp drum is 60mm, the wall length of the counterweight bar is 50mm, the counterweight added to the warp drum roll is 7.5-10kg, the tension applied to the weft weaving monofilament is 0.5-1.5N, and the weaving speed is 1.8-2.5m / hour.

4. The manufacturing process for a high-efficiency vanadium battery electrode material according to claim 1, characterized in that, The carbonization furnace selected in step (4) has a total length of 30m and a heating area of ​​12m. It is carbonized under nitrogen protection. The carbonization temperature of the carbonization furnace is 300-1200℃ and the temperature is increased in stages within the 12m area.

5. The manufacturing process for a high-efficiency vanadium battery electrode material according to claim 1, characterized in that, The air activation furnace selected in step (5) has a length of 12m and a width of 1m. Its furnace chamber is a space of 12x1x0.2m, and the heating temperature is between 450-600℃.

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