Flow battery coil pipe and processing technology thereof

Abstract

The invention discloses a flow battery coil pipe and a processing technology thereof, relates to the technical field of new energy storage, and realizes efficient inhibition of bypass current of a flow battery energy storage system through a multi-dimensional structural design. The spiral body extends the path, the protrusions and the variable-diameter section enhance turbulence, the flow guide ribs optimize the flow track, the shielding layer guides away stray current, the bypass current intensity is greatly reduced through the multi-structure synergistic effect, energy loss is reduced, and the system efficiency is improved. The composite structure body is adopted, insulation, corrosion resistance and strength are considered, the copper net shielding layer is anti-aging, the whole body adapts to severe working conditions such as electrolyte corrosion and pressure fluctuation, and the service life is remarkably prolonged.

Description

Technical Field

[0001] This invention relates to the field of new energy storage technology, specifically to a flow battery coil and its processing technology. Background Technology

[0002] Flow battery energy storage systems have gained widespread attention in the field of new energy storage due to their high safety, long cycle life, and good scalability. However, the bypass current problem in this system seriously affects its performance.

[0003] Bypass current leads to energy loss and reduces system efficiency. During the operation of a flow battery energy storage system, as the electrolyte circulates, potential differences between different battery cells create bypass current, causing some electrical energy to be lost directly without effective conversion. Simultaneously, bypass current accelerates internal corrosion of the battery, shortening its lifespan. This is because the bypass current intensifies localized chemical reactions, damaging critical components such as the battery electrodes and separators.

[0004] Currently, the main methods for suppressing bypass current include optimizing battery structure and using new materials. However, these methods are either structurally complex, requiring significant modifications to the overall battery structure, which increases the difficulty of production and assembly and is costly; or their suppression effect is not ideal and cannot meet the needs of practical applications, failing to fundamentally solve the problems caused by bypass current.

[0005] Therefore, developing a device that is simple in structure, low in cost, and can effectively suppress the bypass current of a flow battery energy storage system is of great practical significance. Summary of the Invention

[0006] To address the aforementioned shortcomings of the prior art, this invention provides a flow battery coil and its processing technology.

[0007] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: A flow battery coil and its processing technology are provided, including at least one section of coil for extending the flow path of electrolyte. The coil has corrosion-resistant and insulating properties and can increase the resistance value of the flowing electrolyte within the system operating pressure range, thereby suppressing the system bypass current.

[0008] Furthermore, the coil has a spiral structure, and its two ends are connected to the inlet and outlet pipes of the flow battery energy storage system, respectively.

[0009] Furthermore, the inner diameter of the coil is 20~60 mm, the wall thickness is 1~5 mm, and the length of the coil is 5~15 meters; the corrosion-resistant insulating material used for the coil is thermoplastic material, including but not limited to: PP, PE, PPH, PVDF or U-PVC.

[0010] Furthermore, the inner wall of the coil is provided with several protrusions, the height of which is 0.5~2mm and the spacing between them is 5~10mm.

[0011] The protrusions can disrupt the flow of the electrolyte, increase the turbulence of the electrolyte, further prolong the residence time of the electrolyte in the coil, and improve the effect of suppressing bypass current.

[0012] Furthermore, the outer side of the coil is wrapped with a shielding layer made of conductive material and grounded. The shielding layer has a copper mesh braided structure with a mesh diameter of 0.5~1mm and a thickness of 0.2~0.5mm.

[0013] The shielding layer can absorb and conduct away any stray currents that may be generated, further enhancing the suppression of bypass currents. Compared to traditional copper foil shielding layers, the copper mesh braided structure has a larger surface area, which can more effectively absorb and conduct away stray currents. It is also more flexible, easier to wrap around the outside of the coil, and lighter in weight, reducing its impact on the overall system weight.

[0014] Furthermore, a temperature control layer is wrapped around the outside of the shielding layer. The temperature control layer is made of thermally conductive silicone material with a thickness of 2-5mm. Several nickel-chromium alloy heating wires and platinum resistance temperature sensors are embedded inside the temperature control layer. The heating wires and temperature sensors are connected to an external temperature controller through wires.

[0015] The temperature control layer can heat or keep the coil warm according to the temperature of the electrolyte, so that the electrolyte is kept within a suitable temperature range. This avoids the electrolyte viscosity from increasing due to excessively low temperature, which would affect the flow performance, or the electrolyte chemical reaction from excessively high temperature, which would accelerate the reaction. This stabilizes the performance of the electrolyte and indirectly enhances the suppression effect on bypass current.

[0016] Furthermore, the inner wall of the coil is also provided with spiral guide ribs, which are aligned with the spiral direction of the coil, with a height of 1~3mm and a pitch of 10~20mm.

[0017] The spiral guide ribs can guide the electrolyte to flow along the spiral path, avoiding local stagnation or short-circuit flow of the electrolyte in the coil, extending the actual flow path of the electrolyte, and enhancing the turbulence intensity of the electrolyte, thereby improving the suppression effect on bypass current.

[0018] Furthermore, the coil adopts a composite structure, consisting of a polytetrafluoroethylene (PTFE) layer, a glass fiber reinforcement layer, and a polyvinyl chloride (PVC) layer from the inside out. The PTFE layer has a thickness of 0.5~1mm; the glass fiber reinforcement layer has a thickness of 1~2mm; and the PVC layer has a thickness of 0.3~0.8mm.

[0019] Furthermore, the coil is provided with several variable diameter sections at intervals. The diameter of the variable diameter section is 0.8 to 0.9 times the diameter of the adjacent normal section, the length is 5 to 10 cm, and the distance between adjacent variable diameter sections is 15 to 25 cm.

[0020] The variable diameter section can change the flow velocity of the electrolyte, causing pressure fluctuations in the electrolyte during flow, further disrupting the flow state of the electrolyte, enhancing the turbulence effect, and prolonging the residence time of the electrolyte in the coil, thereby improving the effect of suppressing bypass current.

[0021] The present invention also provides a processing technology for the above-mentioned flow battery coil, comprising the following steps: S1: Cut a straight pipe to the required length; S2: Place the part of the straight tube that needs to be bent into the heating coil, the temperature of the heating coil is 80~100℃; S3: The rear end of the straight pipe is fixed and locked to the feeding mechanism; S4: After the tube body softens, start the feeding mechanism and feed the bent part into the bending die according to the feeding pitch. S5: Start the bending mechanism to bend the shape according to the dimensions; S6: Repeat S4~S5 to complete the subsequent multiple bends; S7: After bending, perform an air leak test to complete the subsequent assembly.

[0022] The beneficial effects of this invention are as follows: This invention achieves efficient suppression of bypass current in flow battery energy storage systems through multi-dimensional structural design. By extending the path with a spiral body, enhancing turbulence with protrusions and variable diameter sections, optimizing the flow trajectory with guide ribs, and guiding stray current with a shielding layer, the synergistic effect of multiple structures significantly reduces the intensity of bypass current, reduces energy loss, and improves system efficiency.

[0023] The composite structure body takes into account insulation, corrosion resistance and strength. The copper mesh shielding layer is anti-aging and the whole can adapt to harsh working conditions such as electrolyte corrosion and pressure fluctuation, significantly extending the service life. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the coil assembly in Example 1; Figure 2 This is a schematic diagram of the internal structure of the coil; Figure 3 This is a schematic diagram of the cross-section along the length of the coil; Figure 4 This is a schematic diagram of the coil assembly in Example 2; Among them, 1. Coil; 11. Polytetrafluoroethylene layer; 12. Glass fiber reinforcement layer; 13. Polyvinyl chloride layer; 2. Protrusion; 3. Spiral guide rib; 4. Shielding layer; 5. Variable diameter section; 6. Temperature control layer. Detailed Implementation

[0025] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0026] Example 1 like Figures 1-3 As shown, a flow battery coil includes at least one section for extending the electrolyte flow path. The coil has corrosion-resistant and insulating properties, increasing the resistance of the flowing electrolyte within the system's operating pressure range, thereby suppressing the system bypass current. The coil 1 has a spiral structure, with its two ends connected to the inlet and outlet pipes of the flow battery energy storage system, respectively. In specific implementations, when connected to the flow battery energy storage system, both the positive and negative terminals of the system are equipped with coils 1, forming a coil group with two coils 1 wound together. The diameter of the coil 1 is DN40, and its length is 7m. The coil 1 is hot-bent, with a minimum thickness of 2.8mm, a pipe roundness deviation of no more than 2%, and a pipe diameter deviation of no more than 1%. After hot bending, an airtightness test is performed, with 0.4MPa compressed air flowing through the pipe and pressure maintained for 2 hours without leakage. In practice, the diameter of the coil can be DN25 or DN60; the length of the coil can be 5m, 10m or 15m; and the wall thickness of the coil can be 1mm, 3mm or 5mm. The corrosion-resistant insulating material used for the coil is a thermoplastic material, including but not limited to: PP, PE, PPH, PVDF or U-PVC.

[0027] The inner wall of the coil 1 is provided with several protrusions 2, each 1 mm high and spaced 8 mm apart. In practice, the height of the protrusions 2 can also be 0.5 or 2 mm, and the spacing can be 5 or 10 mm. The inner wall of the coil 1 is also provided with spiral guide ribs 3, which are aligned with the spiral direction of the coil 1, have a height of 2 mm, and a pitch of 15 mm. In practice, the height can also be 1 or 3 mm, and the pitch can be 10 or 20 mm. The protrusions 2 are provided on both the inner wall of the pipe and the guide ribs, and when the protrusions 2 are located on the guide ribs, they are close to the axis of the pipe.

[0028] The outer side of the coil 1 is wrapped with a shielding layer 4, which is made of conductive material and is grounded.

[0029] The shielding layer 4 is a copper mesh braided structure with a mesh diameter of 0.8 mm and a thickness of 0.3 mm. In specific implementations, the mesh diameter can also be 0.5 or 1 mm, and the thickness can also be 0.2 or 0.5 mm.

[0030] A temperature control layer 6 is wrapped around the outside of the shielding layer 4. The temperature control layer 6 is made of thermally conductive silicone material and is 3mm thick. Several nickel-chromium alloy heating wires and platinum resistance temperature sensors are embedded inside the temperature control layer 6. The heating wires and temperature sensors are connected to an external temperature controller through wires, which can keep the electrolyte within a suitable temperature range of 25~35℃. In specific implementations, the thickness of the temperature control layer 6 can also be 2 or 5mm.

[0031] The coil 1 adopts a composite structure, consisting of a polytetrafluoroethylene (PTFE) layer 11, a glass fiber reinforcement layer 12, and a polyvinyl chloride (PVC) layer 13 from the inside out. The PTFE layer 11 has a thickness of 0.8 mm; the glass fiber reinforcement layer 12 has a thickness of 1.5 mm; and the PVC layer 13 has a thickness of 0.5 mm. In specific implementations, the thickness of the PTFE layer 11 can also be 0.5 or 1 mm; the glass fiber reinforcement layer 12 can also be 1 or 2 mm; and the PVC layer 13 can also be 0.3 or 0.8 mm.

[0032] The coil 1 has 25 variable diameter sections 5 spaced apart. The diameter of each variable diameter section 5 is 0.8 times the diameter of the adjacent normal section, and its length is 8 cm. The distance between adjacent variable diameter sections 5 is 20 cm. In specific implementations, the diameter of each variable diameter section 5 can also be 0.9 times the diameter of the adjacent normal section, and its length can also be 5 or 10 cm. The distance between adjacent variable diameter sections 5 can also be 15 or 25 cm.

[0033] The following method is used for preparation: S1: Cut a 7m straight pipe; the straight pipe is made of UPVC chemical pipe, which conforms to GB / T4219.1-2008 standard; S2: Place the part of the straight tube that needs to be bent into the heating coil, the temperature of the heating coil is 80~100℃; S3: The rear end of the straight pipe is fixed and locked to the feeding mechanism; S4: After the tube body softens, start the feeding mechanism and feed the bent part into the bending die according to the feeding pitch. S5: Start the bending mechanism to bend the shape according to the dimensions; S6: Repeat S4~S5 to complete the subsequent multiple bends; S7: After bending, perform an air leak test to complete the subsequent assembly.

[0034] Example 2 like Figure 4 As shown, the difference between this embodiment and embodiment 1 is that the coil 1 of a set of fuel cell stacks in the flow battery energy storage system is composed of four pipes, which are distributed in two layers, one above the other, and each layer of coil 1 is bent and coiled.

Claims

1. A flow battery coil, characterized in that, It includes at least one section of coil for extending the flow path of the electrolyte, the coil having corrosion-resistant and insulating properties, which can increase the resistance of the flowing electrolyte within the system operating pressure range, thereby suppressing the system bypass current.

2. The flow battery coil according to claim 1, characterized in that, The coil has a spiral structure, and its two ends are connected to the inlet and outlet pipes of the flow battery energy storage system, respectively.

3. The flow battery coil according to claim 1 or 2, characterized in that, The inner diameter of the coil is 20-60 mm, the wall thickness is 1-5 mm, and the length of the coil is 5-15 meters. The corrosion-resistant insulating material used in the coil is a thermoplastic material, including but not limited to: PP, PE, PPH, PVDF or U-PVC.

4. The flow battery coil according to claim 1, characterized in that, The inner wall of the coil is provided with several protrusions, the height of which is 0.5~2mm and the spacing between them is 5~10mm.

5. The flow battery coil according to claim 1, characterized in that, The outer side of the coil is wrapped with a shielding layer made of conductive material and grounded; the shielding layer has a copper mesh braided structure with a mesh diameter of 0.5~1mm and a thickness of 0.2~0.5mm.

6. The flow battery coil according to claim 5, characterized in that, The outer side of the shielding layer is wrapped with a temperature control layer. The temperature control layer is made of thermally conductive silicone material with a thickness of 2-5mm. Several nickel-chromium alloy heating wires and platinum resistance temperature sensors are embedded inside the temperature control layer. The heating wires and temperature sensors are connected to an external temperature controller through wires.

7. The flow battery coil according to claim 1, characterized in that, The inner wall of the coil is also provided with a spiral guide rib. The spiral guide rib is in the same spiral direction as the coil, with a height of 1~3mm and a pitch of 10~20mm.

8. The flow battery coil according to claim 1, characterized in that, The coil adopts a composite structure, consisting of a polytetrafluoroethylene (PTFE) layer, a glass fiber reinforcement layer, and a polyvinyl chloride (PVC) layer from the inside out. The PTFE layer has a thickness of 0.5~1mm; the glass fiber reinforcement layer has a thickness of 1~2mm; and the PVC layer has a thickness of 0.3~0.8mm.

9. The flow battery coil according to claim 1, characterized in that, The coil is provided with several variable diameter sections at intervals. The diameter of the variable diameter section is 0.8 to 0.9 times the diameter of the adjacent normal section, the length is 5 to 10 cm, and the distance between adjacent variable diameter sections is 15 to 25 cm.

10. A processing method for a flow battery coil according to any one of claims 1 to 9, characterized in that, The following steps are used: S1: Cut a straight pipe to the required length; S2: Place the part of the straight tube that needs to be bent into the heating coil, the temperature of the heating coil is 80~100℃; S3: The rear end of the straight pipe is fixed and locked to the feeding mechanism; S4: After the tube body softens, start the feeding mechanism and feed the bent part into the bending die according to the feeding pitch. S5: Start the bending mechanism to bend the shape according to the dimensions; S6: Repeat S4~S5 to complete the subsequent multiple bends; S7: After bending, perform an air leak test to complete the subsequent assembly.

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