Flame retardant fire resistant solar photovoltaic cable

Abstract

This invention provides a flame-retardant and fire-resistant solar photovoltaic cable, comprising: a cable body; multiple passive cooling modules detachably fixed to the periphery of the cable body, including an inner sheathing layer arranged in a ring and filled with magnesium hydroxide powder; an outer sheathing layer coaxially arranged with the inner sheathing layer and covering the outside of the inner sheathing layer, filled with aluminum hydroxide powder; a heat conductor, rod-shaped, extending from the periphery of the outer sheathing layer and penetrating both the outer and inner sheathing layers; and a piercing component located within the outer sheathing layer, which pierces the outer sheathing layer through a thermal reaction of aluminum hydroxide and discharges the resulting liquid into the surrounding environment. This technical solution, through the thermal decomposition of magnesium hydroxide and aluminum hydroxide, achieves the effect of delaying fire and reducing property damage.

Description

Technical Field

[0001] This invention generally relates to the field of cables, and specifically to a flame-retardant and fire-resistant solar photovoltaic cable. Background Technology

[0002] With the rapid development of the global new energy industry, solar photovoltaic power generation systems have been widely used due to their clean and renewable characteristics. As the core component for power transmission in photovoltaic power generation systems, solar photovoltaic cables need to be exposed to complex outdoor environments for extended periods, facing multiple challenges such as high temperatures, ultraviolet radiation, humidity, wind and sand, and potential fire risks. Their flame-retardant and fire-resistant properties are directly related to the safe and stable operation of the entire photovoltaic system.

[0003] Currently, the industry's technical approaches to improving the flame-retardant and fire-resistant properties of solar photovoltaic cables mainly focus on optimizing the cable's sheathing materials (such as insulation and sheathing layers). Specifically, this is usually achieved by adding a large amount of flame retardants (such as aluminum hydroxide, magnesium hydroxide, and intumescent flame retardants) to the sheathing materials, or by using high-temperature resistant substrates (such as fluoroplastics and silicone rubber) to improve the material's flame-retardant rating and fire resistance limit.

[0004] However, the above-mentioned technical solutions centered on improving the coating material have significant limitations: on the one hand, the procurement cost of high-performance flame retardants and high-temperature resistant substrates is high, and in order to achieve the ideal flame retardant and fire-resistant effect, the proportion of such materials added to the coating layer usually needs to reach 30%-60%, which increases the raw material cost of the cable; on the other hand, due to the adjustment of the composition, the modified coating material has increased processing difficulty, which further increases the production and manufacturing cost of the cable.

[0005] Furthermore, for already laid photovoltaic cables, if an upgrade to a flame-retardant and fire-resistant rating is required, traditional sheathing material improvements necessitate replacing the entire cable. This is not only costly but also leads to extended system downtime and additional economic losses. Therefore, current technology lacks a low-cost, flexible flame-retardant and fire-resistant solution suitable for solar photovoltaic cables. In particular, there is an urgent need for a fire-resistant module that can be detachably connected to the cable body to rapidly enhance its safety protection capabilities in fire scenarios without significantly increasing the overall cost of the cable, thus meeting the pressing needs of photovoltaic systems for flame-retardant and fire-resistant cable performance. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention provides a flame-retardant and fire-resistant solar photovoltaic cable, comprising: a cable body; multiple passive cooling modules detachably fixed to the periphery of the cable body, including an inner sheath layer arranged in a ring and filled with magnesium hydroxide powder; an outer sheath layer coaxially arranged with the inner sheath layer and covering the outside of the inner sheath layer, filled with aluminum hydroxide powder; a heat conductor in the shape of a rod, passing through the periphery of the outer sheath layer and simultaneously passing through the outer and inner sheath layers; and a piercing component located inside the outer sheath layer, which pierces the outer sheath layer through the thermal reaction of aluminum hydroxide and discharges the liquid generated by the reaction into the surrounding environment.

[0007] With the aforementioned technical features, the passive cooling module can be adjusted in quantity according to the cable's laying location. On the one hand, it provides auxiliary support for the cable, and on the other hand, in the event of a fire, the heat conductor transfers the external ambient temperature to the outer and inner sheaths, causing magnesium hydroxide and aluminum hydroxide to react. This triggers the penetration component to pierce the outer sheath, dispersing the water generated by the powder around the cable, thus slowing the spread of the fire and reducing property damage.

[0008] In some embodiments, the puncture assembly includes

[0009] The syringe has a sealed tip and multiple liquid outlets located on the periphery of its end, and is slidably connected to the outer coating layer.

[0010] A force-bearing plate, fixed to the other end of the needle, has multiple filter ports located in the liquid inlet area of ​​the needle. Thus, when the powder within the outer coating reacts with heat, the resulting liquid increases the pressure within the outer coating. This pressure pushes the force-bearing plate, causing the tip of the needle to pierce the side wall of the outer coating. The liquid is then discharged through the needle to the periphery of the outer coating, achieving the effects of flame retardancy and delaying the spread of fire. Furthermore, initially placing the needle inside the outer coating reduces the overall space occupied by the module and improves its ease of transport.

[0011] In some embodiments, a heat-conducting mesh is provided within the inner and outer covering layers, and the heat-conducting mesh abuts against the heat-conducting body. Thus, the heat-conducting mesh and the heat-conducting body are in contact, enabling rapid transfer of external ambient temperature to the peripheral space of the inner and outer covering layers through the heat-conducting body, improving heat transfer efficiency and further enhancing the reaction efficiency of magnesium hydroxide and aluminum hydroxide.

[0012] In some embodiments, a limiting tube is fixed to the heat-conducting mesh, and the needle of the puncture assembly is inserted into the limiting tube. Thus, the limiting tube provides a fixing carrier for the needle, restricting the fixing area and sliding path of the needle, allowing the needle to be punctured specifically in a designated area, ensuring the stability of the puncture operation.

[0013] In some embodiments, the inner ring wall of the inner covering layer is provided with

[0014] A support layer, which is annular, is provided with multiple auxiliary support mechanisms for sliding contact with the cable body. These auxiliary support mechanisms include...

[0015] bracket,

[0016] Ball bearings, which rotate within the bracket;

[0017] A support rod is fixed to the other side of the bracket, passes through the support layer, and is slidably connected to the support layer;

[0018] A support spring is sleeved on the outside of the support rod, with its two ends abutting against one side of the bracket and the support layer, respectively. Thus, the support layer limits the inner diameter of the module, allowing operators to select a suitable size based on the cable diameter.

[0019] In some embodiments, the bracket is an arc-shaped support covering the periphery of the roller, with a gap between its inner wall and the ball, and a support post protruding from the bottom inner wall of the bracket to support the roller. Thus, the bracket ensures rolling connection with the ball, while the support post ensures the gap between the ball and the bracket, reducing the friction between the rolling ball and the bracket.

[0020] In some embodiments, the support rod has a hollow structure in the middle, and its end located within the support layer is a pointed tip.

[0021] The bracket has multiple connecting holes in the connection area with the support rod.

[0022] Furthermore, multiple drainage holes are provided around the perimeter of the bracket. Thus, when the support layer slides within the fixed area around the cable body, the support rod can be pressed into the inner sheath. In the event of a fire, the powder inside the inner sheath reacts to generate liquid, which flows through the support rod into the bracket and is eventually discharged through the drainage holes to the perimeter of the cable body, effectively cooling the perimeter of the cable body and preventing the spread of fire.

[0023] In some embodiments, a plurality of limiting teeth are fixed on the periphery of the support rod along its length. Thus, the limiting teeth, on the one hand, restrict the separation of the support rod from the support layer, ensuring the sliding of the support rod and the support layer is limited; on the other hand, when the support rod is inserted into the inner coating layer, the limiting teeth increase the frictional force with the powder inside the inner coating layer, ensuring the stability of the support rod inserted into the inner coating layer.

[0024] In some embodiments, the outer coating layer has an annular groove, and the heat conductor passes through the bottom wall of the groove. Thus, the groove protects the heat conductor, preventing its end from directly contacting the external environment and avoiding the activation of the passive cooling module due to excessively high temperatures in localized areas.

[0025] In some embodiments, a heat insulation ring is provided within the groove. This ensures that the end of the heat conductor is isolated by the heat insulation ring during normal placement or transportation of the passive cooling module, resulting in a more constant temperature of the heat conductor and improved safety during use.

[0026] It should be understood that the description in the Summary of the Invention is not intended to limit the key or essential features of the embodiments of this disclosure, nor is it intended to restrict the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0027] Figure 1 A schematic diagram of the overall structure of a flame-retardant and fire-resistant solar photovoltaic cable according to an embodiment of the present invention is shown.

[0028] Figure 2 A cross-sectional view of a passive cooling module in a flame-retardant and fire-resistant solar photovoltaic cable according to an embodiment of the present invention is shown.

[0029] Figure 3 This diagram illustrates the structure of a heat insulation ring in a flame-retardant and fire-resistant solar photovoltaic cable according to an embodiment of the present invention.

[0030] Figure 4 This diagram illustrates a heat-conducting mesh area structure in a flame-retardant and fire-resistant solar photovoltaic cable according to an embodiment of the present invention.

[0031] Figure 5 This diagram illustrates the internal structure of the support layer in a flame-retardant and fire-resistant solar photovoltaic cable according to an embodiment of the present invention.

[0032] Figure 6 A cross-sectional view of the internal structure of a bracket in a flame-retardant and fire-resistant solar photovoltaic cable according to an embodiment of the present invention is shown.

[0033] Symbol Explanation

[0034] 1. Cable body; 2. Passive cooling module; 3. Support layer; 4. Inner sheath layer; 41. Magnesium hydroxide; 5. Outer sheath layer; 51. Groove; 52. Heat conductor; 53. Heat insulation ring; 54. Aluminum hydroxide; 6. Heat-conducting mesh; 61. Limiting tube; 7. Puncture assembly; 71. Needle; 711. Liquid outlet; 72. Force plate; 722. Filter outlet; 8. Auxiliary support mechanism; 81. Support rod; 82. Bracket; 821. Drain hole; 822. Connecting hole; 83. Ball bearing; 84. Support column; 85. Support spring; 86. Limiting teeth. Detailed Implementation

[0035] The preferred embodiments (or implementation methods) of the present invention will now be described in detail with reference to the accompanying drawings.

[0036] The following is for reference. Figures 1-6 This invention describes a flame-retardant and fire-resistant solar photovoltaic cable according to an embodiment of the present invention.

[0037] Figure 1 A schematic diagram of the overall structure of a flame-retardant and fire-resistant solar photovoltaic cable according to an embodiment of the present invention is shown. (Reference) Figure 1 As shown, the flame-retardant and fire-resistant solar cable provided in this embodiment includes a cable body 1 and a passive cooling module 2 sleeved around the cable body 1. The passive cooling module 2 is generally ring-shaped and has various sizes and models. The appropriate size is selected according to the diameter of the cable body 1 so that the inner diameter of the passive cooling module 2 is larger than the diameter of the cable body 1, so as to meet the normal sliding of the passive cooling module 2 around the cable body 1.

[0038] Furthermore, multiple passive cooling modules 2 can be installed, with their density adjusted according to the installation area of ​​the cable body 1, so that the radiation area of ​​the passive cooling modules 2 can cover the cable body 1. Moreover, the spacing of the passive cooling modules 2 provides auxiliary support for the cable body 1, keeping the cable body 1 away from the ground and improving its heat dissipation efficiency.

[0039] Figure 2 A cross-sectional view of a passive cooling module 2 in a flame-retardant and fire-resistant solar photovoltaic cable according to an embodiment of the present invention is shown. (See reference) Figure 2 As shown, the passive cooling module 2 consists of three parts from the inside out: a support layer 3, an inner covering layer 4, and an outer covering layer 5.

[0040] The support layer 3 is a ring-shaped plate, which can be made of a plastic material and coated with a refractory coating on its outer surface. This refractory coating can be a ceramicized coating, which can form a hard ceramic shell at high temperatures, providing excellent thermal insulation. Alternatively, the support layer 3 can be made of ceramic matrix composite material, specifically using ceramic as the matrix and reinforced with advanced materials to enhance the ceramic's refractory properties, hardness, and fiber toughness. The support layer 3 also contains an annular chamber, which reduces the overall weight of the module and provides fixed space for other structural elements.

[0041] The inner covering layer 4 is shell-shaped and ring-shaped, surrounding the outer periphery of the support layer 3. Specifically, the inner covering layer 4 can be a ceramic matrix composite material with excellent fire resistance, making it less likely to damage the overall structure of the passive cooling module 2 and affect its overall performance in the high-temperature environment of a fire. The inner covering layer 4 is filled with magnesium hydroxide 41 powder, which decomposes at 330-450 degrees Celsius, and the reaction formula is as follows:

[0042] ,

[0043] The water vapor produced by decomposition occupies space in the combustion zone, dilutes the concentration of combustibles and oxygen, reduces the probability of contact between combustibles and oxygen in the gas phase, and allows the combustion reaction to continue. Moreover, when the water vapor diffuses in the gas phase, it absorbs some heat and cools the surrounding environment of the flame, further reducing the temperature of the material surface and helping to suppress the spread of combustion.

[0044] The outer coating layer 5 is a shell made of the same material as the inner coating layer 4, and it is ring-shaped around the outside of the outer coating layer 5. The outer coating layer 5 is filled with aluminum hydroxide powder 54, which decomposes at 200-300 degrees Celsius. The reaction formula is as follows:

[0045] ,

[0046] Since the outer coating layer 5 is located on the outside of the overall passive cooling module 2, it is able to sense changes in the external environment first. Therefore, aluminum hydroxide 54 is placed inside the outer coating layer 5 so that it can sense changes in ambient temperature first and react accordingly. Moreover, its effect is the same as the decomposition effect of magnesium hydroxide 41.

[0047] Specifically, magnesium hydroxide 41 and aluminum hydroxide 54 are each placed independently in a ring-shaped bag container, thereby restricting the flow of the powder.

[0048] like Figure 2As shown, an annular groove 51 is formed on the outer periphery of the outer coating layer 5. Multiple rod-shaped heat conductors 52 are inserted into the bottom wall of the groove 51 towards the support layer 3. The heat conductors 52 are cylindrically arranged around the outer coating layer 5 and simultaneously inserted into the inner coating layer 4. The heat conductors 52 can be made of copper rods, which have a high thermal conductivity, enabling them to promptly transfer the temperature of the external environment towards the inner coating layer 4, thereby triggering the decomposition reaction of magnesium hydroxide 41 and aluminum hydroxide 54. Furthermore, since the ends of the heat conductors 52 are located on the bottom wall of the groove 51, they are less likely to directly contact the external environment, reducing the probability of accidental contact.

[0049] Figure 3 A schematic diagram of the structure of the heat insulation ring 53 in a flame-retardant and fire-resistant solar photovoltaic cable according to an embodiment of the present invention is shown. (Reference) Figure 3 As shown, to ensure the stability of the passive cooling module 2 during normal storage and transportation, a ring-shaped heat insulation ring 53 is also fitted inside the groove 51. The heat insulation ring 53 can be a mica-based composite material, with natural mica sheets as the base material and reinforced with composite glass fiber cloth or silicone resin. It has excellent heat insulation performance and low thermal conductivity, which can effectively block heat transfer. With the heat insulation ring 53 in place, the end area of ​​the heat conductor 52 is covered and isolated, making the temperature of the heat conductor 52 more constant and less susceptible to temperature interference from the external environment.

[0050] Figure 4 A schematic diagram of the heat-conducting mesh 6 region structure in a flame-retardant and fire-resistant solar photovoltaic cable according to an embodiment of the present invention is shown. (Reference) Figure 4 As shown, to improve the thermal conductivity of the heat conductor 52, a mesh-like heat-conducting mesh 6 is provided inside both the inner cladding layer 4 and the outer cladding layer 5. The heat-conducting mesh 6 is made of pure copper and is attached to the outer walls of both the inner cladding layer 4 and the outer cladding layer 5. This serves two purposes: firstly, it provides auxiliary support for the inner cladding layer 4 and the outer cladding layer 5; secondly, it accelerates the transfer of heat from the heat conductor 52 to the space between the inner cladding layer 4 and the outer cladding layer 5, improving the efficiency of heat transfer and allowing the reaction between aluminum hydroxide 54 and magnesium hydroxide 41 to be more complete.

[0051] Multiple limiting tubes 61 are also provided on the heat-conducting mesh 6 attached to the outer covering layer 5, and each limiting tube 61 is provided with a puncture assembly 7. Specifically, the puncture assembly 7 includes a needle tube 71 inserted into the limiting tube 61. The tip of the needle tube 71 is sealed, and a liquid outlet 711 communicating with the interior is opened on the periphery of the tip of the needle tube 71. A force plate 72 is fixed to the other end of the needle tube 71. Multiple filtration ports 722 communicating with the interior of the needle tube 71 are opened on the force plate 72. The force plate 72 is located in the bag of aluminum hydroxide 54 powder, and the outer covering area corresponding to the tip of the needle tube 71 is open and is filled with a temporary rubber stopper.

[0052] In a fire environment, as the temperature of the external environment rises, the heat conductor 52 transfers heat to the inner covering layer 4 and the outer covering layer 5. When the temperature reaches the decomposition degree of aluminum hydroxide 54, a large amount of water vapor will be generated, which will increase the pressure of the outer covering layer 5. Since the aluminum hydroxide 54 is located under the bag, it will limit the range of pressure transmission and squeeze the stress plate 72, causing the tip of the needle 71 to protrude from the outer wall of the outer covering layer 5, and then spread the water vapor generated by decomposition to the surrounding environment.

[0053] Figure 5 This diagram illustrates the internal structure of the support layer 3 in a flame-retardant and fire-resistant solar photovoltaic cable according to an embodiment of the present invention. Figure 6 A cross-sectional view of the internal structure of a bracket 82 in a flame-retardant and fire-resistant solar photovoltaic cable according to an embodiment of the present invention is shown. (See reference) Figure 5 Figure 6 As shown, in order to disperse the water vapor generated by magnesium hydroxide 41 in the environment around the cable body 1, the support layer 3 is also provided with a number of auxiliary support mechanisms 8. The auxiliary support mechanism 8 includes a support rod 81 that passes through the inside of the support layer 3. The support rod 81 is a hollow structure with a pointed end facing the inner covering layer 4. The other end of the support rod 81 is fixed to a bracket 82. A ball bearing 83 is rotatably connected inside the bracket 82. Specifically, the bracket 82 is an arc-shaped plate covering the periphery of the ball bearing 83, so that there is a gap between the bracket 82 and the ball bearing 83. A support column 84 is provided protruding from the bottom wall inside the bracket 82, which supports the bottom wall of the ball bearing 83 and stably limits the ball bearing 83 to the end area of ​​the bracket 82. The bracket 82 has a number of connecting holes 822 that communicate with the inside of the support rod 81, and a number of drainage holes 821 are provided on the periphery of the bracket 82. A support spring 85 is sleeved on the outside of the support rod 81. The two ends of the support spring 85 abut against one side of the support layer 3 and the bottom wall of the bracket 82, respectively. Multiple limiting teeth 86 are fixed on the periphery of the support rod 81 inside the support layer 3, thereby restricting the separation of the support rod 81 from the support layer 3.

[0054] Furthermore, the support layer 3 has an opening at the tip of the support rod 81, allowing the tip of the support rod 81 to be inserted into the bag containing magnesium hydroxide 41 by sliding the support rod 81. After the magnesium hydroxide 41 decomposes upon heating, the water vapor produced flows through the support rod 81 toward the bracket 82, and finally flows out through the drain hole 821 on the bracket 82 to the periphery of the cable body 1, thereby achieving cooling and mitigating the fire.

[0055] In actual operation, the support layer 3 is sleeved on the cable. Under the elastic action of the support spring 85, the ball bearing 83 abuts against the periphery of the cable body 1, thereby allowing the passive cooling module 2 to slide more quickly on the cable body 1. When the passive cooling module 2 slides to the setting area of ​​the cable body 1, the support layer 3 is gripped and the ball bearing 83 is squeezed, causing the support spring 85 to compress elastically. The support rod 81 is inserted into the bag of strong magnesium oxide. Due to the setting of the limiting teeth 86, the friction between the support rod 81 and the magnesium hydroxide 41 powder is increased, thereby limiting the sliding of the support rod 81 in the strong magnesium oxide powder. When the magnesium hydroxide 41 decomposes at high temperature, the water vapor generated will radiate to the periphery of the cable body 1.

[0056] Furthermore, to avoid blockage inside the support rod 81, its tip is designed with the same structure as the needle tube 71, making the tip of the support rod 81 a sealed opening. Water vapor will enter through the holes opened around the tip of the support rod 81, thereby greatly reducing the occurrence of powder blockage.

[0057] In the description of this specification, the terms "connection," "installation," and "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0058] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A flame-retardant and fire-resistant solar photovoltaic cable, characterized in that, include: Cable body (1), Passive cooling modules (2), of which multiple modules are provided, are detachably fixed to the periphery of the cable body (1), and include The inner coating layer (4) is arranged in a ring shape and filled with magnesium hydroxide (41) powder. The inner ring wall of the inner coating layer (4) is provided with... A support layer (3) is annular, and a plurality of auxiliary support mechanisms (8) are provided thereon for sliding contact with the cable body (1). The auxiliary support mechanisms (8) include: Bracket (82), The ball (83) is rotatably connected inside the bracket (82). The bracket (82) is an arc-shaped support body covering the ball (83) around its periphery. There is a gap between its inner wall and the ball (83). A support column (84) for supporting the roller is protruding on the bottom wall of the bracket (82). A support rod (81) is fixed to the other side of the bracket (82) and passes through the support layer (3), and is slidably connected to the support layer (3). The middle part of the support rod (81) is hollow, and its end located in the support layer (3) is a pointed tip. The bracket (82) has multiple connecting holes (822) in the connection area with the support rod (81); Furthermore, the bracket (82) has multiple drainage holes (821) on its periphery; A support spring (85) is sleeved on the outside of the support rod (81), with its two ends abutting against one side of the bracket (82) and the support layer (3), respectively. The outer coating layer (5) is coaxially arranged with the inner coating layer (4) and covers the outside of the inner coating layer (4), and its interior is filled with aluminum hydroxide (54) powder. The heat conductor (52) is rod-shaped and is inserted through both the outer covering layer (5) and the inner covering layer (4) from the periphery of the outer covering layer (5). The puncture assembly (7), located inside the outer covering layer (5), punctures the outer covering layer (5) through the heating reaction of aluminum hydroxide (54) and discharges the liquid generated by the reaction into the surrounding environment.

2. The flame-retardant and fire-resistant solar photovoltaic cable according to claim 1, characterized in that, The puncture assembly (7) includes The syringe (71) has a sealed tip and multiple liquid outlets (711) on its end periphery, which are slidably connected to the outer covering layer (5). A force plate (72) is fixed to the other end of the needle tube (71), and multiple filter ports (722) are provided in the inlet area of ​​the needle tube (71).

3. The flame-retardant and fire-resistant solar photovoltaic cable according to claim 2, characterized in that, A heat-conducting mesh (6) is installed inside the inner covering layer (4) and the outer covering layer (5), and the heat-conducting mesh (6) abuts against the heat conductor (52).

4. The flame-retardant and fire-resistant solar photovoltaic cable according to claim 3, characterized in that, A limiting tube (61) is fixed on the heat-conducting mesh (6), and the needle tube (71) of the puncture assembly (7) is inserted into the limiting tube (61).

5. The flame-retardant and fire-resistant solar photovoltaic cable according to claim 1, characterized in that, The support rod (81) has a plurality of limiting teeth (86) fixed on its periphery along its length.

6. The flame-retardant and fire-resistant solar photovoltaic cable according to claim 1, characterized in that, The outer covering layer (5) has an annular groove (51), and the heat conductor (52) passes through the bottom wall of the groove (51).

7. The flame-retardant and fire-resistant solar photovoltaic cable according to claim 6, characterized in that, A heat insulation ring (53) is provided inside the groove (51).

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