A hydrogen barrier sealing skin, a lighter-than-air vehicle, and a hydrogen barrier sealing method

Abstract

The present application relates to the technical field of aerostat, and particularly relates to a hydrogen-blocking sealing skin, an aerostat and a hydrogen-blocking sealing method, which comprises, from inside to outside, a water storage functional layer, an airtight isolation layer and a protective outer layer; the water storage functional layer comprises a water-absorbing polymer and a porous support body, the water-absorbing polymer is used for adsorbing and holding liquid water under normal temperature conditions, and the porous support body is used for providing a storage space and an ice formation limited environment for the liquid water. A continuous ice shielding layer is formed by in-situ freezing in the pores of the porous support body, so that the ice layer and the airtight isolation layer cooperatively constitute a hydrogen-tight sealing barrier structure, thereby replacing the traditional chemical hydrogen-blocking coating in a physical sealing mode. The present application replaces the chemical coating with a pure physical ice layer to block hydrogen, has self-healing ability and can be applied to the fields of green hydrogen air transportation and zero-carbon computing power.

Description

Technical Field

[0001] This invention relates to the field of airship technology, specifically to a hydrogen-blocking sealing skin, an airship, and a hydrogen-blocking sealing method. Background Technology

[0002] Airships (including airships and high-altitude balloons) utilize gases lighter than air to provide lift, offering unique advantages in long-endurance aerial monitoring, communication relay, and cargo transport. Currently, helium is commonly used as the buoyancy medium in airships; however, helium resources are scarce, expensive, and non-renewable, significantly limiting the large-scale engineering applications of airships. Hydrogen, with its higher buoyancy efficiency and low-cost, renewable production through water electrolysis, is an ideal candidate to replace helium. However, the small diameter and high penetrability of hydrogen molecules place far higher technical demands on the sealing and barrier properties of airship envelope materials than on helium. Furthermore, the current cost of large-scale green hydrogen transportation is relatively high, making airships themselves the preferred carrier for green hydrogen air transport.

[0003] Existing airship envelope materials are typically composed of a load-bearing fabric layer and an airtight layer. To achieve efficient hydrogen barrier, engineering practices commonly employ coating or bonding chemical hydrogen-barrier coatings (such as polyvinylidene chloride-based coatings, ethylene-vinyl alcohol copolymer coatings, aluminum foil composite films, or aluminized barrier films) to the inner wall of the envelope. These coatings suppress hydrogen permeation through the dense structure of organic polymers or the physical barrier of the metal layer. While the hydrogen barrier performance of these chemical or inorganic coatings generally meets requirements under laboratory conditions, during actual airship service, the envelope undergoes alternating diurnal temperature variations, high-altitude low-temperature flexible bending, and ultraviolet irradiation aging. The difference in thermal expansion coefficients between the coating / film and the base fabric leads to interfacial stress accumulation, making it prone to aging and cracking under long-term cyclic action. After 2 to 3 years of use, the hydrogen barrier performance significantly degrades, failing to meet the long-life service requirements of airships.

[0004] In addition, with the continuous expansion of artificial intelligence computing power, high altitude has the advantage of natural cold source, which is suitable for deploying computing equipment. However, existing high-altitude computing power systems generally suffer from insufficient power supply at night and difficulty in dissipating waste heat from the whole machine.

[0005] Existing literature (Patterson and Saltzman, J. Geophys. Res. Atmos., 2021) reports the hydrogen permeability characteristics of cryogenic ice layers, but this literature only involves permeability coefficient measurements at the material level and does not address the sealing application of ice layers in the flexible bladder of airships. Furthermore, the aviation industry has traditionally considered cabin icing a safety hazard and has therefore sought to mitigate it; currently, there are no relevant technical solutions for constructing physical hydrogen barriers using in-situ icing. Summary of the Invention

[0006] In view of this, the present invention provides a hydrogen-blocking sealing skin, an air levitation device, and a hydrogen-blocking sealing method to solve the problems of chemical hydrogen-blocking aging cracking and degradation.

[0007] In a first aspect, the present invention provides a hydrogen-barrier sealing skin, comprising a water storage functional layer, an airtight isolation layer and a protective outer layer arranged sequentially from the inside to the outside; The water storage functional layer includes a water-absorbing polymer and a porous support. The water-absorbing polymer is used to adsorb and retain liquid water under normal temperature conditions, and the porous support is used to provide storage space and a freezing confinement environment for the liquid water. When the ambient temperature drops below 0°C, the liquid water held in the water storage layer freezes in situ in the pores of the porous support, forming a continuous ice shielding layer that interpenetrates with the porous support. The continuous ice shielding layer and the airtight isolation layer together form a sealed barrier structure against hydrogen.

[0008] In this application, a continuous ice shielding layer is formed by in-situ freezing within the pores of a porous support. This ice layer, together with the airtight isolation layer, constitutes a hydrogen-sealing barrier structure, thus replacing the traditional chemical hydrogen barrier coating with a physical seal. Since the ice layer is formed in-situ in the low-temperature environment of the airship's operation, there are no issues with coating curing shrinkage or interfacial stress caused by differences in thermal expansion coefficients between the coating and the base material. This avoids the inherent defects of chemical hydrogen barrier coatings, such as aging and cracking under high-altitude low-temperature alternation, flexible bending, and ultraviolet irradiation. Simultaneously, the porous support provides a confined support environment for the ice layer, causing it to form a pre-stress state due to pore constraint during freezing and expansion. This pre-stress can drive the closure of cracks when microcracks appear in the ice layer due to deformation of the capsule, overcoming the technical obstacle of sealing failure caused by the inherent brittleness of pure ice. This enables the in-situ ice layer to achieve long-term stable operation in a flexible structure, providing a feasible sealing technology solution for airships to use low-cost, renewable hydrogen instead of scarce and expensive helium as the buoyancy medium. This invention replaces chemical coatings with a purely physical ice layer for hydrogen blocking, possesses self-healing capabilities, and is suitable for green hydrogen air transport and zero-carbon computing power.

[0009] In one alternative embodiment, the porous support is configured to apply confined compressive stress to the ice body when the liquid water freezes in situ, enabling the continuous ice shielding layer to have self-healing capabilities when microcracks are generated.

[0010] In this application, when liquid water freezes within the closed pores of a porous support, the volume expansion of ice crystals is physically constrained by the rigid pore walls, preventing free outward expansion. This results in the accumulation of compressive internal stress within the ice body and at the interface between the ice body and the pore walls. When microcracks develop in the continuous ice shielding layer due to repeated bending, vibration, or thermal expansion and contraction of the airship capsule in a low-temperature environment, this pre-stored confined compressive stress drives the ice bodies on both sides of the crack to move towards each other, causing the crack to tend to close. This automatically restores the seal integrity without external energy input or human intervention, overcoming the crack propagation problem caused by the inherent brittleness of pure ice layers. It also avoids the inherent defects of chemical hydrogen barrier coatings, such as the inability to repair microcracks and the irreversible degradation of hydrogen barrier performance.

[0011] In one alternative implementation, the self-healing capability comprises a triple mechanism of confined compressive stress closure, stress-induced compressive melting-recrystallization welding, and sublimation-condensation densification across crack migration.

[0012] In this application, a triple self-healing mechanism provides redundant repair paths for microcracks of different scales and under different environmental conditions: confined compressive stress closure is effective throughout the entire process of crack initiation and propagation; stress-induced compressive melting-recrystallization welding utilizes the local stress concentration generated by the deformation of the capsule, and based on the principle of pressure reducing the freezing point, it melts local ice crystals into water to fill the crack, and recrystallizes and welds after stress release, providing active filling and repair capabilities for penetrating cracks; sublimation-deposition cross-crack migration densification utilizes the sublimation-deposition mass transfer of ice crystals at the crack edge under low temperature and low humidity conditions to complete the dense reconstruction of ice crystals on the crack surface, which is suitable for the slow damage accumulation during long-duration flight. The three mechanisms complement each other, enabling the continuous ice shielding layer to maintain its sealing integrity under various operating conditions such as reciprocating takeoffs and landings and long-duration flight.

[0013] In one optional embodiment, the water-absorbing polymer retains no less than 95% of its water content after standing for 24 hours under a 10 kPa compressive load and at 25°C. The porosity of the porous support is 60% to 85%.

[0014] In this application, the water-absorbing polymer maintains a water retention rate of no less than 95% after standing for 24 hours under a 10 kPa compressive load and 25°C. This ensures that the adsorbed liquid water in the water storage layer will not be lost due to gravity compression or evaporation during the entire ground preparation and ascent phase from ground water injection to freezing in the air. This guarantees that there will still be sufficient water in the water storage layer to form a continuous and complete ice shielding layer when reaching the low-temperature airspace. The porosity of the porous support is set to 60% to 85%. On the one hand, this provides sufficient water storage space and a margin for ice volume expansion, avoiding excessive ice expansion that could cause destructive stress to the hydrogen barrier sealing skin structure. On the other hand, this porosity range ensures a moderate spacing between the pore walls, enabling the formation of a mechanically interwoven continuous ice-skeleton composite after the ice freezes. This ensures that the ice layer has sufficient thickness to effectively block hydrogen while also possessing sufficient structural strength to resist the risk of cracking caused by bending deformation of the capsule, thus achieving an optimal balance between water storage capacity and structural stability.

[0015] In one optional embodiment, the outer surface of the protective outer layer is coated with a photovoltaic film, and the protective outer layer and the anti-ultraviolet encapsulation layer on the surface of the photovoltaic film together constitute a dual ultraviolet protection structure.

[0016] In this application, after a photovoltaic (PV) film is laminated onto the outer surface of the protective outer layer, the PV film and the UV-resistant encapsulation layer on the surface of the protective outer layer together constitute a dual UV protection structure. In this dual-layer protection configuration, the UV-resistant encapsulation layer, as the first line of defense, directly faces the strong UV radiation at high altitudes, absorbing or reflecting most of the UV light and slowing down the aging rate of the PV film material itself. The protective outer layer, as the second line of defense, further blocks residual UV light that penetrates the UV-resistant encapsulation layer, while protecting the underlying airtight isolation layer and water storage layer from UV damage. Thus, with sufficient UV protection, the PV film can provide continuous photoelectric conversion capability for the aerostat without the need for an additional heavy protective cover due to insufficient UV protection. This maintains the lightweight characteristics of the hydrogen-barrier sealing skin, extends the service life of the PV film and the entire capsule structure, and reduces the frequency of maintenance and replacement during long-term high-altitude deployments.

[0017] Secondly, the present invention also provides an airship, comprising: The main airbag has a wall made of the aforementioned hydrogen-barrier sealing skin and is filled with hydrogen. The electrical load is located inside the main airbag; A fuel cell for converting the hydrogen into electrical energy to supply the electrical load; The waste heat generated by the electrical load and / or the fuel cell during operation is transferred to the continuous ice shielding layer of the main airbag through the natural convection of hydrogen gas inside the main airbag, and dissipated by the phase change heat absorption of the continuous ice shielding layer.

[0018] In this application, the airship uses hydrogen in the main airbag as both the buoyancy medium and fuel for the fuel cell, combining the functions of energy storage medium and buoyancy medium. This eliminates the need for a separate fuel tank, reducing the structural weight and volume of the airship. Waste heat generated by electrical loads and fuel cell operation would normally be a burden on the airship's thermal management. However, this application utilizes hydrogen in the main airbag as a heat transfer medium, transferring the waste heat to a continuous ice shielding layer on the airbag wall via natural convection. The ice layer dissipates the heat through phase change absorption. The ice layer absorbs the waste heat that would otherwise require an active cooling system, resulting in partial melting. The capillary action of the porous support allows the meltwater to remain in situ, refreezing as the temperature decreases. This dynamic phase change process achieves passive heat dissipation and releases accumulated stress within the ice layer through periodic thaw-freeze cycles, further enhancing the structural stability of the ice layer.

[0019] In one optional embodiment, the airship further includes a secondary airship connected to but not in communication with the main airship. The secondary airship is connected to an air pump and a valve for inflating or deflating air from the outside to adjust the buoyancy balance of the airship.

[0020] In this application, when landing is required, air is pumped into the auxiliary gasbag to increase the overall weight, making the airship's gravity greater than its buoyancy for a smooth descent. When takeoff or cruising is required, the air in the auxiliary gasbag is expelled to restore it to a state lighter than air. The auxiliary gasbag is separate from the main gasbag that stores hydrogen, and the pumped air and hydrogen do not come into contact, avoiding the risk of combustion and explosion caused by the mixing of hydrogen and oxygen. At the same time, the volume change of the auxiliary gasbag does not change the total amount of hydrogen in the main gasbag. Therefore, the buoyancy adjustment process does not cause hydrogen emission or additional replenishment, which saves hydrogen resources and maintains a relatively stable hydrogen pressure in the main gasbag. This is beneficial for maintaining the structural integrity of the ice shield layer on the gasbag wall and the long-term stability of the hydrogen-blocking sealing effect.

[0021] In one optional embodiment, the cathode side of the fuel cell is connected to the outside atmosphere via an independent pipeline, while the anode side is connected to the hydrogen in the main gasbag, and the cathode side and anode side are physically isolated from each other. During operation, hydrogen in the main gasbag and outside air are used as fuel, and the by-product water generated during operation is guided to a water storage tank via a recovery pipeline.

[0022] In this application, the fuel cell operates using hydrogen from the main gasbag and outside air as raw materials. The by-product water generated is guided to the water storage tank through a recycling pipeline, realizing the in-situ recycling of fuel cell water, providing a water source for subsequent electrolysis and hydrogen replenishment, while avoiding the free accumulation of liquid water inside the gasbag.

[0023] In one optional embodiment, the outer surface of the protective outer layer is coated with a photovoltaic power generation film. The electrical energy generated by the photovoltaic power generation film is used to supply the electrical load and to electrolyze the by-product water in the water storage tank. The oxygen generated after the by-product water is electrolyzed is discharged to the outside, and the hydrogen generated is introduced into the main airbag.

[0024] In this application, the electricity generated by the photovoltaic film is used not only to supply the electrical load, but also to electrolyze the by-product water in the water storage tank. The oxygen produced by electrolysis is discharged to the outside and the hydrogen is introduced into the main airbag, forming a complete closed water and hydrogen circulation loop. This allows the hydrogen consumed by the fuel cell to be replenished by photovoltaic water electrolysis, ensuring the self-sustaining aloft time of the airship under conditions without external supply.

[0025] In one optional embodiment, the aerostat further includes an energy storage battery, which is a low-temperature sodium-ion battery or a modified lithium-ion battery, used for powering the device to start up in low-temperature environments and for smoothing and compensating for instantaneous power fluctuations of the electrical load.

[0026] In this application, the sodium-ion battery maintains good ionic conductivity even at low temperatures, while the modified lithium-ion battery reduces its low-temperature internal resistance through electrolyte optimization and electrode modification. Both ensure reliable instantaneous high-current output when the airship starts up electrical equipment in a high-altitude, low-temperature environment. When the power demand of the electrical load fluctuates drastically, the energy storage battery quickly responds to compensate for the power gap or absorb the power surplus, allowing the fuel cell to operate in a relatively stable optimal efficiency range, avoiding performance degradation and shortened lifespan caused by frequent load changes. When the output power of the photovoltaic membrane drops sharply due to cloud cover, the energy storage battery can seamlessly switch to power supply, ensuring the continuity of power supply to the electrical load.

[0027] In one optional embodiment, the airship further includes an optoelectronic composite tether cable connected to a ground base station; when the optoelectronic composite tether cable is normally connected, the ground power supply serves as the main power supply circuit, the fuel cell serves as an emergency backup power supply in case of cable failure, and the energy storage battery serves as an uninterrupted backup power supply.

[0028] In this application, the ground power source continuously supplies electricity via a tether cable, supporting higher-power electrical loads. Simultaneously, surplus electricity generated by the photovoltaic film is prioritized for water electrolysis to produce hydrogen for storage. In the event of an accidental breakage of the tether cable, the fuel cell immediately switches to emergency backup power, while the energy storage battery provides uninterrupted power during the switchover, forming a three-level redundant power supply architecture: ground power source – fuel cell – energy storage battery. This ensures that the electrical load does not lose power or shut down under fault conditions such as tether cable disconnection, and the aerostat still has sufficient power to implement a safe recovery procedure.

[0029] In one alternative embodiment, the electrical load is encapsulated in a sealed metal container with heat dissipation fins, the metal container being suspended in the internal space of the main airbag, thereby physically isolating the electrical load from the hydrogen gas inside the main airbag.

[0030] In this application, the electrical load is encapsulated within a sealed metal container with heat dissipation fins and suspended inside the main airbag. This sealed metal container physically isolates the precision electrical equipment from the hydrogen gas inside the main airbag, eliminating the risk of ignition that may arise from hydrogen contacting the electrical equipment. The heat dissipation fins of the metal container increase the heat exchange area with the surrounding hydrogen gas. The high-temperature heat flow generated during the operation of the electrical load can be efficiently conducted to the fin surface and heat the surrounding hydrogen gas, forming a strong natural convection driving force. The suspension arrangement places the container inside the airbag rather than attached to the airbag wall, avoiding localized pressure on the ice layer structure of the airbag wall due to the weight of the equipment. At the same time, it allows the heated hydrogen gas to flow evenly upward from all sides of the equipment, forming a circulating convection covering the entire internal cross-section of the airbag. This fully utilizes the large volume of hydrogen gas inside the airbag as a heat buffer medium, maximizing the heat absorption efficiency of the ice layer phase change, and enabling the long-term reliable operation of high-power-density electrical equipment within the sealed airbag.

[0031] In one optional embodiment, the airship is an airship module, and multiple airship modules are spliced ​​together in a low-temperature airspace to form an integral high-altitude base; water-absorbing sealing strips are provided at the splicing edges of adjacent airship modules, and adjacent airship modules rely on water vapor sublimation and ice formation in a low-temperature environment to form an ice-bonded connection layer, thus fixing each airship module into a whole.

[0032] In this application, the water-absorbing sealing strips at the splicing edges of the airship modules absorb and retain moisture. After ascending to the cryogenic airspace, the water vapor at the gaps sublimates and freezes, freezing and fixing the splicing edges of adjacent modules into one, forming an ice-bonded connection layer without adhesives or mechanical connectors. This connection method is similar to the in-situ icing mechanism of the hydrogen-barrier sealing skin, eliminating the need for adhesives or connecting structural components, and the splicing process does not rely on complex aerial operations. Like the ice layer of the skin, the ice-bonded connection layer has low-temperature self-healing capabilities, automatically healing micro-cracks at the joints caused by the deformation of the capsule. Modular splicing significantly reduces the difficulty of manufacturing, transporting, and launching individual modules, and allows for expansion of the splicing scale according to mission requirements, constructing large-scale high-altitude base platforms.

[0033] In one optional embodiment, the geometric thickness t of the continuous ice shielding layer and the porosity of the porous support are... The surface area to volume ratio of the main airbag Satisfying buoyancy constraints: That is, the mass of the continuous ice shielding layer does not exceed 40% of the net buoyancy of the airship; where A is the outer surface area of ​​the main airbag, V is the volume of the main airbag, and t is the geometric thickness of the continuous ice shielding layer as an ice-skeleton composite layer. The density of ice, The difference between the air density and hydrogen density at the stationary altitude; for the surface area to volume ratio Not less than 0.2 For the airship, the geometric thickness of the continuous ice shield does not exceed 1.8 mm; At 0.12 Up to 0.15 For airships within a certain range, the geometric thickness of the continuous ice shield does not exceed 2.5 mm; for No greater than 0.12 For large airships, the geometric thickness of the continuous ice shield layer does not exceed 3.0 mm.

[0034] In this application, the ice mass increases with the skin area (proportional to the square of the radius), while the net buoyancy of the airship increases with the volume (proportional to the cube of the radius). Therefore, the buoyancy constraint limits the upper limit of ice thickness that airships of different sizes can withstand, avoiding excessive ice weight gain that could erode the structural weight and mission load margin. The graded thickness limits are matched with the airship size: smaller airship modules can meet hydrogen barrier requirements with thinner ice layers, while larger airships can bear thicker ice layers to obtain stronger hydrogen barrier margins and phase change thermal storage capacity. This allows the scheme in this application to be implemented in both small modules and large hulls, and meets the constraint that the ice mass does not exceed 40% of the net buoyancy at all operating altitudes.

[0035] Thirdly, the present invention also provides a hydrogen-blocking sealing method for an airship, wherein the main gasbag wall of the airship is made of the aforementioned hydrogen-blocking sealing skin, comprising the following steps: Liquid water is adsorbed and sealed in the water storage layer of the hydrogen-barrier sealing skin on the ground; The airship is raised to an airspace below 0°C, causing the liquid water in the water storage functional layer to freeze in situ in the pores of the porous support, forming a continuous ice shielding layer. The continuous ice shielding layer and the airtight isolation layer are used together to block hydrogen gas.

[0036] In this application, the hydrogen-blocking sealing method for the airship involves absorbing and sealing liquid water on the ground into a water storage layer. After takeoff, the high-altitude, low-temperature environment causes the water in the storage layer to freeze in situ within the pores of a porous support, forming a continuous ice shield layer. This ice shield layer, together with an airtight isolation layer, blocks hydrogen gas. This method replaces the traditional chemical hydrogen-blocking coating or metal barrier membrane sealing process with an in-situ physical ice layer. The airship does not require coating or attaching any chemical hydrogen-blocking materials before takeoff; only ordinary pure water needs to be pre-stored to complete the hydrogen-blocking sealing preparation. This simplifies the airship manufacturing process and ground maintenance procedures, eliminating the inherent risk of chemical hydrogen-blocking coatings aging and cracking due to high-altitude, low-temperature alternation and ultraviolet radiation. Since the ice shielding layer is grown in situ in the service environment of the airship, there is no problem of interface stress accumulation caused by the difference in thermal expansion coefficients of different materials between the interface bonding between it and the porous support and the airtight isolation layer. This enables the application to be repeatedly implemented multiple times with flight missions. It can be re-iced in each flight mission. After each landing, the meltwater of the ice layer is adsorbed and stored in situ by the water storage functional layer for re-icing in the next mission. This realizes the mission-level cyclic reuse of sealing means and extends the effective life of the hydrogen barrier function of the airship body.

[0037] In one optional embodiment, a heat dissipation step is also included: the waste heat generated by the airship's electrical load and / or fuel cell is transferred to the continuous ice shielding layer through the natural convection of hydrogen in the main airbag, and dissipated by the phase change heat absorption melting of the continuous ice shielding layer; after the ambient temperature decreases, the melted water is re-frozen in the porous support body.

[0038] In this application, the heat dissipation step utilizes the natural convection of hydrogen within the main airbag to transfer waste heat generated by the electrical load and fuel cell to the continuous ice shielding layer on the airbag wall. The heat is dissipated through the melting of the ice layer after phase change, and the melt water refreezes within the porous support body as the ambient temperature decreases. This forms a passive thermal management method that eliminates the need for additional working fluid circulation pumps and cooling fans. By utilizing the latent heat of fusion of ice to absorb a large amount of waste heat, continuous heat dissipation of high-power equipment can be achieved with a relatively small ice layer mass. Simultaneously, hydrogen itself functions as both a heat carrier and a buoyancy medium, eliminating the need for separate coolant circulation pipelines and avoiding the risk of equipment damage or electrical short circuits caused by the freezing and expansion of liquid coolant in low-temperature environments. The melted water is retained in situ within the pores due to the capillary action of the porous support, preventing the formation of free liquid water inside the airbag. When the ambient temperature drops, the water refreezes within the pores, restoring the sealing integrity of the ice shield and re-storing the phase change heat absorption capacity. Moreover, each thaw-freeze cycle itself eliminates the stress concentration inside the ice layer caused by long-term freezing, making the ice crystal structure more compact and uniform after each refreeze. Attached Figure Description

[0039] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the cross-sectional structure of the hydrogen-barrier sealing skin according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the overall structure of the tethered airship according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the day-night energy closed-loop process according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the modular high-altitude splicing base structure according to an embodiment of the present invention.

[0041] Explanation of reference numerals in the attached figures: 1. Water storage layer; 2. Airtight isolation layer; 3. Protective outer layer; 4. Continuous ice shielding layer; 5. Photovoltaic power generation film; 6. Photovoltaic composite tethering cable; 7. Ground power supply; 8. Aircraft; 9. Aircraft module; 10. Ice bonding connection layer; 11. Water-absorbing sealing strip; 12. Main airbag; 13. Secondary airbag; 14. Sealed metal container; 15. Fuel cell; 16. Water storage tank; 17. Energy storage battery; 18. Electrolysis equipment; 19. Electrical load. Detailed Implementation

[0042] 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 with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] The following is combined Figures 1 to 4 The following describes embodiments of the present invention.

[0044] Example 1: Basic Structure and Materials of Hydrogen Barrier Sealing Skin This invention provides a hydrogen-blocking sealing skin for an airship, applicable to an airship 8 using hydrogen as the buoyancy medium, such as... Figure 1As shown, it includes a water storage functional layer 1, an airtight isolation layer 2, and a protective outer layer 3 arranged sequentially from the inside out; it does not contain a chemical hydrogen barrier coating. The thickness of the water storage functional layer 1 is 3mm to 15mm, and the dry surface density is 200g / m² to 400g / m². The airtight isolation layer 2 is an airtight base fabric, and the protective outer layer 3 is a weather-resistant protective layer. The water storage functional layer 1 can pre-absorb and seal pure water at room temperature, and includes a water-absorbing polymer and a porous support. The water-absorbing polymer is used to absorb and retain liquid water under room temperature conditions, and the porous support is used to provide storage space and a freezing confinement environment for the liquid water. The water-absorbing polymer can be a highly absorbent and water-retaining material, and the porous support can be a flexible porous skeleton, such as a sponge-like structure.

[0045] The porous support is configured to apply confined compressive stress to the ice body when the liquid water is frozen in situ. The continuous ice shielding layer 4 has the ability to self-heal microcracks. The self-healing ability includes a triple mechanism of confined compressive stress closure, stress-induced compressive melting-recrystallization, and sublimation-deposition densification across crack migration.

[0046] When the ambient temperature drops below 0°C, the liquid water held in the water storage layer 1 freezes in situ in the pores of the porous support, forming a continuous ice shielding layer 4 that interpenetrates with the porous support. The continuous ice shielding layer 4 is a thin ice layer. The continuous ice shielding layer 4 and the airtight isolation layer 2 work together to form a hydrogen sealing barrier. The continuous ice shielding layer 4 has a triple microcrack self-healing capability. The self-healing methods include confined compressive stress closure, stress-induced compressive melting-recrystallization, and sublimation-deposition densification across crack migration.

[0047] Specifically, the triple microcrack self-healing mechanism is as follows: First, the freezing expansion of the ice layer generates pre-compression stress due to the confinement of the skeleton pores, and the pre-compression stress is used to close the crack gap; Second, the deformation of the capsule (the capsule in this application mainly refers to the main air capsule 12) generates local stress concentration, and according to the principle of pressure reducing the freezing point, the local ice layer meltwater fills the gap, and after the stress is released, the water recrystallizes and welds the crack; Third, under low temperature and low humidity environment, the ice crystals at the crack edge sublimate, and water vapor migrates to the low temperature region to condense and deposit, completing the dense reconstruction of ice crystals across the crack.

[0048] The continuous ice shielding layer 4 and the airtight isolation layer 2 together form a sealed barrier structure against hydrogen.

[0049] In this application, a continuous ice shielding layer 4 is formed by in-situ freezing within the pores of a porous support. This ice layer, together with the airtight isolation layer 2, constitutes a hydrogen-sealing barrier structure, thus replacing the traditional chemical hydrogen barrier coating with a physical seal. Since the ice layer is formed in-situ in the low-temperature environment where the airship 8 operates, there are no issues with coating curing shrinkage or interfacial stress caused by differences in thermal expansion coefficients between the coating and the base material. This avoids the inherent defects of chemical hydrogen barrier coatings, such as aging and cracking under high-altitude low-temperature alternation, flexible bending, and ultraviolet irradiation. Simultaneously, the porous support provides a confined support environment for the ice layer, allowing it to form a pre-stress state during freezing and expansion due to pore constraints. This pre-stress can drive crack closure when microcracks appear in the ice layer due to capsule deformation, overcoming the technical obstacle of sealing failure caused by the inherent brittleness of pure ice. This enables the in-situ ice layer to achieve long-term stable operation in a flexible structure, providing a feasible sealing technology solution for the airship 8 to use low-cost, renewable hydrogen as the buoyancy medium instead of scarce and expensive helium. This invention replaces chemical coatings with a purely physical ice layer for hydrogen blocking, possesses self-healing capabilities, and is suitable for green hydrogen air transport and zero-carbon computing power.

[0050] In one alternative embodiment, the porous support is configured to apply confined compressive stress to the ice body when the liquid water freezes in situ, enabling the continuous ice shielding layer 4 to have self-healing capabilities when microcracks are generated.

[0051] In this application, when liquid water freezes within the closed pores of a porous support, the volume expansion of the ice crystals is physically constrained by the rigid pore walls, preventing them from expanding freely outwards. This results in the accumulation of compressive internal stress within the ice body and at the interface between the ice body and the pore walls. When the continuous ice shielding layer 4 develops microcracks due to repeated bending, vibration, or thermal expansion and contraction of the airship 8 capsule in a low-temperature environment, the pre-stored confined compressive stress drives the ice bodies on both sides of the crack to move towards each other, causing the crack gap to tend to close. This automatically restores the seal integrity without the need for external energy input or human intervention, overcoming the crack propagation problem caused by the inherent brittleness of pure ice layers. It also avoids the inherent defects of chemical hydrogen barrier coatings, such as the inability to repair microcracks and the irreversible degradation of hydrogen barrier performance.

[0052] In one optional embodiment, the water-absorbing polymer retains no less than 95% of its water content after standing for 24 hours under a 10 kPa compressive load and at 25°C. The porosity of the porous support is 60% to 85%.

[0053] Specifically, the water-absorbing polymer is a low-temperature resistant cross-linking superabsorbent resin (such as cross-linked sodium polyacrylate SAP), which retains a water rate of not less than 95% after standing for 24 hours at 10 kPa and 25°C; the porous support can be made of polyurethane open-cell sponge or hydrophilic flocked cloth with a porosity of 60% to 85%, which is used to provide storage space and freezing confinement environment for liquid water, buffer freezing expansion stress, and form the stress concentration conditions required for pressure melting and recrystallization.

[0054] The porosity of the porous support is set to 60% to 85%. When the porosity is below 60%, the water storage space is insufficient and the stress from ice expansion cannot be released, which can easily cause the hydrogen-blocking sealing skin to crack. When the porosity is above 85%, the mechanical strength of the skeleton is insufficient, and stable stress concentration conditions cannot be formed, affecting the self-healing effect of the ice layer. For round-trip take-off and landing, the ice layer thickness is set to 0.8mm to 2.5mm. When it is below 0.8mm, the hydrogen blocking effect is insufficient, and when it is above 2.5mm, the weight increase of the hydrogen-blocking sealing skin is too large, affecting the buoyancy performance. For long-duration flight, the ice layer thickness is set to 3.0mm to 6.0mm to ensure the continuous hydrogen blocking effect under long-term stationary conditions.

[0055] When applied to a reciprocating take-off and landing type airship 8, the thickness of the in-situ formed continuous ice shield layer 4 is 0.8 mm to 2.5 mm.

[0056] In this application, the water-absorbing polymer maintains a water retention rate of no less than 95% after standing for 24 hours at 10 kPa and 25°C. This ensures that the adsorbed liquid water in the water storage layer 1 will not be lost due to gravity or evaporation during the entire ground preparation and ascent phase from ground water injection to freezing in the air. This guarantees that there will still be sufficient water in the water storage layer to form a continuous and complete ice shielding layer when reaching the low-temperature airspace. The porosity of the porous support is set to 60% to 85%. On the one hand, this provides sufficient water storage space and capacity to accommodate the expansion of ice volume, avoiding excessive expansion of the ice layer and causing destructive stress to the hydrogen barrier sealing skin structure. On the other hand, this porosity range ensures a moderate spacing between the pore walls, enabling the formation of a mechanically interwoven continuous ice-skeleton composite after the ice freezes. This ensures that the ice layer has sufficient thickness to effectively block hydrogen and sufficient structural strength to resist the risk of cracking caused by bending deformation of the capsule, thus achieving an optimal balance between water storage capacity and structural stability.

[0057] In one optional embodiment, a photovoltaic film 5 is laminated to the outer surface of the protective outer layer 3, and the protective outer layer 3 and the anti-ultraviolet encapsulation layer on the surface of the photovoltaic film 5 together constitute a dual ultraviolet protection structure. The photovoltaic film 5 can be a flexible photovoltaic film.

[0058] In this application, after the outer surface of the protective outer layer 3 is composited with a photovoltaic power generation film 5, the photovoltaic power generation film 5 and the anti-ultraviolet encapsulation layer on the surface of the protective outer layer 3 together constitute a dual ultraviolet protection structure. In this dual-layer protection configuration, the anti-ultraviolet encapsulation layer, as the first line of defense, directly faces the strong ultraviolet radiation at high altitudes, absorbing or reflecting most of the ultraviolet light and slowing down the aging rate of the photovoltaic power generation film 5 material itself; the protective outer layer 3, as the second line of defense, further blocks residual ultraviolet light that penetrates the anti-ultraviolet encapsulation layer, while protecting the underlying airtight isolation layer 2 and water storage functional layer 1 from ultraviolet damage. Thus, with sufficient ultraviolet protection, the photovoltaic power generation film 5 can provide continuous photoelectric conversion capability for the aerostat 8 without the need for an additional heavy protective cover plate due to insufficient ultraviolet protection. This maintains the lightweight characteristics of the hydrogen-blocking sealing skin, extends the service life of the photovoltaic power generation film 5 and the entire capsule structure, and reduces the maintenance and replacement frequency during long-term high-altitude deployments.

[0059] When the ambient temperature drops below 0°C, the liquid water held in the water storage layer 1 freezes in situ within the pores of the porous support, forming a continuous ice shield layer 4 that interpenetrates with the porous support. The continuous ice shield layer 4 and the airtight isolation layer 2 together form a sealed barrier structure against hydrogen. When the liquid water freezes in situ, the porous support applies confined compressive stress to the ice, enabling the continuous ice shield layer 4 to possess microcrack self-healing capabilities. The self-healing mechanisms include confined compressive stress closure, stress-induced compressive melting-recrystallization welding, and sublimation-condensation densification across crack migration—a triple mechanism, detailed in Example 12. The hydrogen barrier effect is insufficient when the geometric thickness of the continuous ice shield layer 4 is less than 0.8 mm; the upper limit of the thickness is determined according to the buoyancy constraint graded according to the scale of the airship 8 (verification process detailed in Example 11): surface area to volume ratio. Not less than 0.2 The thickness of the airship 8 does not exceed 1.8mm. At 0.12 Up to 0.15 The range of the airship 8 does not exceed 2.5mm. No greater than 0.12 For large airships, the diameter should not exceed 3.0 mm; for long-endurance operation, the larger value should be taken within the upper limit of the classification to ensure the continuous hydrogen blocking effect under long-term stationary conditions.

[0060] As a specific material configuration: the water storage layer 1 is made of 3mm thick polyurethane open-cell sponge (75% porosity) impregnated with cross-linked sodium polyacrylate SAP water-absorbing resin; the airtight isolation layer 2 is made of 200D high-strength polyester woven fabric double-sided hot-pressed 0.15mm low-temperature TPU film; the protective outer layer 3 is made of 0.1mm PVDF fluorocarbon protective film. As a long-endurance variant: the water storage layer 1 is 6 to 8mm thick with a dry areal density of 400g / L. The airtight isolation layer 2 is made of aramid fabric double-sided composite 0.25mm TPU, and the outer surface of the protective outer layer 3 is composite with a flexible perovskite photovoltaic film 5. The anti-ultraviolet encapsulation layer on the surface of the photovoltaic film 5 and the protective outer layer 3 together form a dual ultraviolet protection structure.

[0061] Example 2: Overall Structure and Buoyancy Adjustment of Airship 8 The present invention also provides an airship, comprising: The main airbag 12 has a wall made of the hydrogen-blocking sealing skin of Example 1, and is filled with hydrogen. Electrical load 19 is installed inside the main airbag 12; Fuel cell 15 is used to convert the hydrogen into electrical energy to supply the electrical load 19; The waste heat generated during the operation of the electrical load 19 and / or the fuel cell 15 is transferred to the continuous ice shielding layer 4 of the main airbag 12 through the natural convection of hydrogen gas, and dissipated by the phase change heat absorption of the continuous ice shielding layer 4.

[0062] The airship 8, equipped with the aforementioned hydrogen-blocking sealing skin, serves as an integrated hydrogen storage and transportation carrier. The main airbag 12 is filled with hydrogen, which serves as both the buoyancy medium and the storage and transportation medium. In-situ icing under high-altitude and low-temperature conditions achieves hydrogen barrier sealing.

[0063] In this application, the airship 8 uses hydrogen in the main airbag 12 as both the buoyancy medium and the fuel for the fuel cell 15, thus combining the functions of the energy storage medium and the buoyancy medium. This eliminates the need for a separate fuel tank, reducing the structural weight and volume of the airship 8. The waste heat generated by the electrical load 19 and the fuel cell 15 would normally be a burden on the thermal management of the airship 8. However, this application utilizes hydrogen in the main airbag 12 as a heat transfer medium, transferring the waste heat to the continuous ice shielding layer 4 on the airbag wall through natural convection. The ice layer dissipates the heat through phase change absorption. The ice layer absorbs the waste heat that would otherwise require an active cooling system, resulting in partial melting. The capillary action of the porous support allows the meltwater to remain in situ, and it refreezes after the temperature drops. This dynamic phase change process achieves passive heat dissipation and releases the stress accumulation inside the ice layer through periodic thaw-freeze cycles, further enhancing the structural stability of the ice layer.

[0064] In an optional embodiment, a secondary airbag 13 connected to the main airbag 12 is also included. When the secondary airbag 13 is deployed, it is inflated with air to adjust the buoyancy balance of the aerostat 8, thereby achieving ascent and descent control. When the aerostat 8 descends, air is inflated into the independent secondary airbag 13 to increase its own weight for descent; after landing, the ice layer melts, and the meltwater is absorbed and recovered in situ by the water storage functional layer 1. The main airbag 12 and the secondary airbag 13 are connected but not interconnected. An air pump and a valve connected to the air pump can be installed on the secondary airbag 13 for inflating and deflating it from the outside. The main airbag 12 can also be equipped with an air pump and a valve connected to the air pump for introducing or removing hydrogen from the main airbag 12.

[0065] In this application, the auxiliary airbag 13, connected to the main airbag 12, adjusts the buoyancy balance of the airship 8 by inflating it with air when opened, providing a simple and direct ascent / descend control method for the airship 8. When descent is required, air is inflated into the auxiliary airbag 13 to increase the overall weight, making the gravity of the airship 8 greater than its buoyancy for a smooth descent; when ascent or cruising is required, the air in the auxiliary airbag 13 is expelled to restore it to a state lighter than air. The auxiliary airbag 13 is set independently of the main airbag 12, which stores hydrogen, and the inflated air and hydrogen do not come into contact with each other, avoiding the risk of combustion and explosion caused by the mixing of hydrogen and oxygen. At the same time, the volume change of the auxiliary airbag 13 does not change the total amount of hydrogen in the main airbag 12. Therefore, the buoyancy adjustment process of the airship 8 does not cause hydrogen emission or additional replenishment, which saves hydrogen resources and maintains a relatively stable hydrogen pressure in the main airbag 12, which is beneficial to maintaining the structural integrity of the ice shield layer of the airbag wall and the long-term stability of the hydrogen-blocking sealing effect.

[0066] In one optional embodiment, the cathode side of the fuel cell 15 is connected to the outside atmosphere via an independent pipeline, while the anode side is connected to the hydrogen in the main gasbag 12, and the two are physically isolated. During operation, the fuel cell uses hydrogen in the main gasbag 12 and outside air as raw materials, and the by-product water generated during operation is guided to the water storage tank 16 through a recovery pipeline. The electricity generated by the photovoltaic membrane 5 is used to power the electrical load 19 and to electrolyze the by-product water in the water storage tank 16. The oxygen produced after electrolysis of the by-product water is discharged to the outside, while the hydrogen produced is introduced into the main air bladder 12. The oxygen produced after electrolysis of the by-product water can also be stored in an oxygen tank connected to the main air bladder 12. The oxygen tank is connected to the fuel cell 15, and the fuel cell 15 can directly utilize the hydrogen in the main air bladder 12 and the oxygen in the oxygen tank when generating electricity. An electrolysis device 18 can also be installed, with the photovoltaic membrane 5 connected to it. The electricity generated by the photovoltaic membrane 5 powers the electrolysis device 18 to produce hydrogen and oxygen.

[0067] In this application, the fuel cell 15 operates using hydrogen from the main air chamber 12 and outside air as fuel. The generated byproduct water is channeled to the water storage tank 16 via a recovery pipeline, achieving in-situ recovery of the fuel cell 15's produced water. The electricity generated by the photovoltaic membrane 5, in addition to supplying the electrical load 19, is also used to electrolyze the byproduct water in the water storage tank 16. The oxygen produced by electrolysis can be discharged to the outside, while the hydrogen is introduced into the main air chamber 12, forming a complete closed-loop water and hydrogen circulation system. This allows the hydrogen consumed by the fuel cell 15 to be replenished through photovoltaic water electrolysis, ensuring the self-sustaining aerobatic time of the aerostat 8 under conditions without external supply.

[0068] In one alternative implementation, such as Figure 3 As shown, it also includes an energy storage battery 17, which is a low-temperature sodium-ion battery or a modified lithium-ion battery, used for power supply during equipment startup in low-temperature environments and for mitigating and compensating for instantaneous power fluctuations. The recovery pipeline can utilize waste heat from the electrolysis of the fuel cell 15 for freeze protection. The fuel cell 15 can be a hydrogen fuel cell 15. When waste heat is insufficient, the energy storage battery 17 supplies a low-power heating cable to maintain the pipeline temperature and prevent the recovery pipeline from freezing and becoming blocked at low temperatures.

[0069] In this application, the energy storage battery 17 employs a low-temperature sodium-ion battery or a modified lithium-ion battery, specifically designed for power supply during equipment startup and for mitigating instantaneous power fluctuations in low-temperature environments. Since sodium-ion batteries maintain good ionic conductivity at low temperatures, and modified lithium-ion batteries reduce low-temperature internal resistance through electrolyte optimization and electrode modification, both ensure reliable instantaneous high-current output when the aerostat 8 starts up electrical equipment in high-altitude, low-temperature environments. When the power demand of the electrical load 19 fluctuates drastically, the energy storage battery 17 quickly responds to compensate for power shortages or absorb power surpluses, allowing the fuel cell 15 to operate within a relatively stable optimal efficiency range, avoiding performance degradation and shortened lifespan of the fuel cell 15 due to frequent load changes. Furthermore, when the output power of the photovoltaic film 5 drops sharply due to cloud cover, the energy storage battery 17 can seamlessly provide power, ensuring the continuity of power supply to the electrical load 19.

[0070] At the application level, there are two directions: First, the airship 8 serves as a hydrogen storage and transportation carrier to realize an air transport solution for green hydrogen in addition to land routes; second, a photovoltaic power generation film 5 is installed on the outside of the hydrogen barrier sealing skin, which, together with the electrolysis hydrogen production, fuel cell 15, and energy storage battery 17, forms a fully closed-loop energy system. It utilizes the natural convection thermosiphon of hydrogen in the main airbag 12, and relies on the latent heat of phase change of the ice layer to absorb computing power and waste heat from power generation to achieve cooling without external energy consumption; with the configuration of a tethered photovoltaic composite cable, it can be connected to the ground mains power, forming a dual power redundancy architecture between air and ground.

[0071] like Figure 4As shown, the airship 8 can be used as an airship module 9. Multiple airship modules 9 are spliced ​​together in a low-temperature airspace. The splicing edges of the airship modules 9 are sealed with highly absorbent resin. The ice-bonded connection layer 10 without adhesive is formed by the sublimation and freezing of water vapor in the low-temperature environment, which fixes each airship module 9 into an integral high-altitude base.

[0072] This application can construct a closed-loop energy system spanning day and night, consisting of photovoltaic membrane 5 on the outer side of the hydrogen-blocking sealed skin. During the day, electricity is generated by the photovoltaic membrane 5 on the outer side of the hydrogen-blocking sealed skin, and the electricity is preferentially supplied to the electrical load 19 (such as computing equipment). Excess electricity is used to produce hydrogen through water electrolysis and stored in the main gasbag 12. At night, the fuel cell 15 is the main power supply unit, and the energy storage battery 17 is the auxiliary energy storage unit, which jointly provides power. The waste heat generated by the computing equipment and the fuel cell 15 is transferred to the ice layer on the gasbag wall by the thermosiphon of the hydrogen inside the gasbag, and passive cooling is achieved by the heat absorption of the ice layer through phase change.

[0073] Hydrogen gas inside the main airbag 12 forms a passive thermosiphon circuit through natural convection. The heated hydrogen gas diffuses to the ice layer on the airbag wall, releasing heat and cooling down. The cooled hydrogen gas then convects to the electrical load 19.

[0074] The airship 8 can be equipped with multiple hydrogen safety structures. The hydrogen-barrier sealing skin adopts a high-airtightness composite structure to achieve long-term sealing. The main airbag 12 can be equipped with hydrogen leak detection sensors to monitor the leakage status of the airbag in real time. An emergency pressure relief valve is installed on the top of the main airbag 12 to automatically release pressure in case of abnormal overpressure. The entire cabin is treated with anti-static measures to avoid the risk of static electricity ignition. When the hydrogen-barrier sealing skin is damaged or the airbag leaks, the auxiliary airbag 13 can be inflated to increase weight and initiate an emergency landing procedure.

[0075] In one optional embodiment, when the outer surface of the protective outer layer 3 is coated with a photovoltaic power generation film 5, the electrical energy generated by the photovoltaic power generation film 5 is used to supply the electrical load 19 and to electrolyze the by-product water in the water storage tank 16. The oxygen generated after the by-product water is electrolyzed is discharged to the outside, and the hydrogen generated is introduced into the main airbag 12.

[0076] In one alternative implementation, such as Figure 2 As shown, it also includes an optoelectronic composite tethered cable 6 connecting to the ground base station; when the tethered cable is normally connected, the ground power supply 7 serves as the main power supply circuit, the fuel cell 15 serves as an emergency backup power supply in case of cable failure, and the energy storage battery 17 serves as an uninterrupted backup power supply. The optoelectronic composite tethered cable 6 connects the ground power supply 7 and the electrical load 19, enabling the ground power supply 7 to supply power to the electrical load 19.

[0077] In this application, when the photovoltaic composite tether cable 6 is in normal operation, the ground power source 7 serves as the main power supply circuit. This ensures that the aerostat 8 no longer relies entirely on the photovoltaic and fuel cell 15 for power during high-altitude stays. The ground power source 7 continuously supplies power through the tether cable, supporting the operation of higher-power electrical loads 19. Simultaneously, surplus electricity generated by the photovoltaic film 5 is prioritized for water electrolysis to produce hydrogen for storage. In the event of an accidental breakage of the tether cable, the fuel cell 15 immediately switches to emergency backup power to continue supplying power, while the energy storage battery 17 provides uninterrupted power at the moment of switching, forming a three-level redundant power supply architecture: ground power source 7 – fuel cell 15 – energy storage battery 17. This architecture ensures that the electrical load 19 will not lose power or shut down in the event of a tether cable disconnection or other fault conditions, critical data will not be lost, and the aerostat 8 will still have sufficient power to implement a safe recovery procedure.

[0078] Example 3: Light-Hydrogen-Electricity-Ice-Computing Energy Closed-Loop System This embodiment constructs a closed-loop energy system spanning day and night, including light, hydrogen, electricity, ice, and computing, based on Embodiment 2. Figure 3 As shown. The cathode side of the fuel cell 15 is connected to the outside atmosphere through an independent pipeline, while the anode side is connected to the hydrogen inside the main gasbag 12. The cathode side and the anode side are physically isolated from each other. During operation, the fuel cell uses the hydrogen inside the main gasbag 12 and the outside air as raw materials. The generated byproduct water is guided to the water storage tank 16 through a recovery pipeline. The electricity generated by the photovoltaic power generation film 5 composite on the outer surface of the protective outer layer 3 is used to supply the electrical load 19 and to electrolyze the byproduct water in the water storage tank 16 (performed by the electrolysis equipment 18, which can be an alkaline or proton exchange membrane electrolyzer). The oxygen generated after the byproduct water electrolysis is discharged to the outside, and the generated hydrogen is introduced into the main gasbag 12, forming a complete closed water and hydrogen circulation loop. As a variant, the oxygen generated by electrolysis can also be stored in an oxygen tank connected to the main gasbag 12. When the fuel cell 15 generates electricity, it can directly utilize the hydrogen inside the main gasbag 12 and the oxygen in the oxygen tank.

[0079] The energy storage battery 17 is a low-temperature sodium-ion battery or a modified lithium-ion battery, used for power supply during equipment startup in low-temperature environments and for mitigating and compensating for instantaneous power fluctuations in the electrical load 19. The recovery pipeline utilizes the waste heat from the fuel cell 15 and the electrolysis equipment 18 for freeze protection. When the waste heat is insufficient, the energy storage battery 17 supplies a low-power heating cable to maintain the pipeline temperature and prevent the recovery pipeline from freezing and blocking at low temperatures.

[0080] The day and night operation process is as follows: During the day, the photovoltaic film 5 generates electricity, which is preferentially supplied to the electrical load 19 (such as onboard computing equipment). The surplus electricity is electrolyzed into hydrogen by the electrolysis equipment 18. The hydrogen is stored in the main gasbag 12. The by-product oxygen from electrolysis is discharged or stored as needed. The excess heat of the electrolysis equipment 18 is used to preheat the recovery pipeline to reduce auxiliary heat energy consumption. At night, the fuel cell 15 serves as the main power supply unit and the energy storage battery 17 serves as the auxiliary energy storage unit to jointly supply power. The energy storage battery 17 smooths out the instantaneous computing power peak. The waste heat generated by the electrical load 19 and the fuel cell 15 is transferred to the continuous ice shielding layer 4 of the gasbag wall by the natural convection thermosiphon of the hydrogen in the gasbag. Passive cooling is achieved by the phase change heat absorption of the ice layer: the heated hydrogen diffuses to the ice layer of the gasbag wall to release heat and cool down. The cooled hydrogen convection returns to the electrical load 19 to form a passive circulation heat dissipation.

[0081] Example 4: Electrical load 19 enclosed suspension and passive heat dissipation The electrical load 19 (e.g., a computing cluster or computing device) is encapsulated in a sealed metal container 14 with heat dissipation fins. The metal container is suspended in the internal space of the main airbag 12, physically isolating the electrical load 19 from the hydrogen gas inside the main airbag 12.

[0082] In this application, the electrical load 19 is encapsulated within a sealed metal container 14 with heat dissipation fins and suspended inside the main airbag 12. The sealed metal container 14 physically isolates the precision electrical equipment from the hydrogen gas inside the main airbag 12, eliminating the risk of ignition that may occur if hydrogen comes into contact with the electrical equipment. The heat dissipation fins of the metal container increase the heat exchange area with the surrounding hydrogen gas. The high-temperature heat flow generated when the electrical load 19 is running can be efficiently conducted to the fin surface and heat the surrounding hydrogen gas, forming a strong natural convection driving force. The suspension arrangement places the container inside the airbag rather than attached to the airbag wall, avoiding local pressure on the ice layer structure of the airbag wall due to the weight of the equipment. At the same time, it allows the heated hydrogen gas to flow evenly upward from all sides of the equipment, forming a circulating convection that covers the entire internal cross-section of the airbag. This fully utilizes the large volume of hydrogen gas inside the airbag as a heat buffer medium, maximizing the heat absorption efficiency of the ice layer phase change, and enabling the long-term reliable operation of high-power-density electrical equipment within the sealed airbag 8. The ice layer absorbs waste heat and partially melts. The capillary action of the porous support keeps the meltwater in situ. It then refreezes when the temperature drops. This dynamic phase change process achieves both passive heat dissipation and releases the accumulated stress inside the ice layer through periodic thaw-freeze cycles.

[0083] Example 5 The present invention also provides a method for hydrogen-blocking sealing of an airship, comprising the following steps: Liquid water is adsorbed and sealed in the water storage functional layer 1 of the hydrogen barrier sealing skin on the ground; The airship 8 is raised to an airspace below 0°C, causing the liquid water in the water storage functional layer 1 to freeze in situ in the pores of the porous support, forming a continuous ice shielding layer 4. The continuous ice shielding layer 4 and the airtight isolation layer 2 are used together to block hydrogen gas.

[0084] In this application, the hydrogen-blocking sealing method for the airship 8 involves absorbing and sealing liquid water on the ground into a water storage layer 1. After takeoff, the high-altitude, low-temperature environment causes the water in the storage layer to freeze in situ within the pores of the porous support, forming a continuous ice shield layer 4. This ice shield layer, together with the airtight isolation layer 2, blocks hydrogen gas. This method achieves a sealing process that replaces traditional chemical hydrogen-blocking coatings or metal barrier films with an in-situ physical ice layer. The airship 8 does not require any chemical hydrogen-blocking materials to be coated or bonded before takeoff; only ordinary pure water needs to be pre-stored to complete the hydrogen-blocking sealing preparation. This simplifies the manufacturing process of the airship and the ground maintenance procedures, eliminating the inherent risk of aging and cracking of chemical hydrogen-blocking coatings due to high-altitude, low-temperature alternation and ultraviolet radiation. Since the ice shielding layer is grown in situ in the service environment of the airship 8, there is no problem of interface stress accumulation caused by the difference in thermal expansion coefficients of different materials between the interface bonding between it and the porous support and the airtight isolation layer 2. This enables the application to be repeatedly implemented in the flight mission cycle. It can be re-iced in each flight mission. After each landing, the meltwater of the ice layer is adsorbed and stored in situ by the water storage functional layer 1 for re-icing in the next mission. This realizes the mission-level cyclic reuse of the sealing means and extends the effective life of the hydrogen blocking function of the airship 8 capsule.

[0085] In an optional embodiment, a heat dissipation step is also included: the waste heat generated by the electrical load 19 and / or fuel cell 15 of the airship 8 is transferred to the continuous ice shielding layer 4 through the natural convection of hydrogen in the main airbag 12, and dissipated by the phase change heat absorption melting of the continuous ice shielding layer 4; after the ambient temperature drops, the melted water is re-frozen in the porous support body.

[0086] In this application, the heat dissipation step utilizes the natural convection of hydrogen within the main airbag 12 to transfer waste heat generated by the electrical load 19 and fuel cell 15 to the continuous ice shielding layer 4 on the airbag wall. The heat is dissipated by the melting of the ice layer through phase change. Once the ambient temperature decreases, the melted water refreezes within the porous support body, forming a passive thermal management method that eliminates the need for additional working fluid circulation pumps and cooling fans. By utilizing the latent heat of molten ice to absorb a large amount of waste heat, continuous heat dissipation of high-power equipment can be achieved with a relatively small ice layer mass. Simultaneously, hydrogen itself functions as both a heat carrier and a buoyancy medium, eliminating the need for separate coolant circulation pipelines and avoiding the risk of equipment damage or electrical short circuits caused by the freezing and expansion of liquid coolant in low-temperature environments. The melted water is retained in situ within the pores due to the capillary action of the porous support, preventing the formation of free liquid water inside the airbag. When the ambient temperature drops, the water refreezes within the pores, restoring the sealing integrity of the ice shield and re-storing the phase change heat absorption capacity. Moreover, each thaw-freeze cycle itself eliminates the stress concentration inside the ice layer caused by long-term freezing, making the ice crystal structure more compact and uniform after each refreeze.

[0087] This method has the capability to be repeated multiple times during flight missions: the ice layer refreezes during each flight mission, and the meltwater from the ice layer is adsorbed and stored in situ by the water storage layer 1 after each landing, and will refreeze during the next mission, thus realizing the mission-level cyclic reuse of the sealing means and extending the effective lifespan of the hydrogen blocking function of the airship 8 capsule.

[0088] Example 6: Basic hydrogen barrier sealing skin structure and in-situ icing hydrogen barrier and self-healing properties like Figure 1 As shown, the water storage functional layer 1 is: a 3mm thick polyurethane open-cell sponge (porosity 75%) impregnated with cross-linked sodium polyacrylate SAP water-absorbing resin. The airtight isolation layer 2 is made of 200D high-strength polyester woven fabric double-sided hot-pressed 0.15mm low-temperature TPU film; The outer protective layer 3 is a 0.1mm PVDF fluorocarbon protective film.

[0089] This invention utilizes the high-altitude, low-temperature environment of the airship 8 to generate a continuous thin ice layer in situ within the porous skeleton of the inner layer of the hydrogen-blocking sealing skin. The dense hydrogen bond network of the ice forms a physical hydrogen-blocking barrier, which works in conjunction with the airtight isolation layer 2 to achieve efficient hydrogen-blocking sealing.

[0090] The theoretical basis for the triple self-healing mechanism of ice is as follows: First, the freezing expansion of the ice layer, constrained by the porous framework, generates pre-compression stress. According to the principles of solid mechanics, this pre-compression stress can drive the crack surface to close after crack formation. Second, the deformation of the capsule causes local stress concentration. According to the principle of pressure lowering the freezing point (Clapeyron equation), the freezing point in the local high-pressure area decreases, causing ice crystals to melt locally and fill the crack gaps with water. After the stress is released, the water recrystallizes and welds the crack. This pressure-melt-recrystallization mechanism has been systematically described in glacier mechanics literature. Third, under low temperature and low humidity conditions, ice crystals at the crack edge sublimate, and water vapor condenses and deposits in areas with even lower temperatures, completing the dense reconstruction of ice crystals across the crack. The sublimation-condensation mass transfer process has been reported in porous ice media. When the ice layer thickness is 2 mm and the capsule curvature radius is 5 m, the bending stress can reach the local pressure-melt condition of the ice body, realizing stress-induced melting and welding.

[0091] Example 7: Application of Green Hydrogen Round-Trip Airlift Aircraft 8 Before takeoff, the main airbag 12 is filled with floating hydrogen at the green hydrogen production base, and cargo materials are loaded. It ascends to a 3000m low-temperature airspace with an ambient temperature of -5℃ to -15℃, where the inner layer of water freezes to form a 0.8 to 2.5mm hydrogen-blocking ice layer. After arriving at the destination airspace, air is injected into the isolation auxiliary airbag 13 to increase its weight for landing. Upon landing, the ice layer melts, and the meltwater is completely absorbed and stored by the SAP material. The hydrogen in the main airbag 12 is extracted and connected to the storage and transportation pipeline network. The empty main airbag 12 can be folded and reused for return.

[0092] Example 8: Tethered Air-Ground Integrated Computing Platform like Figure 2 As shown, based on the structure of Example 3, a photoelectric composite tether cable 6 is configured. The photoelectric composite tether cable 6 integrates load-bearing aramid fiber, high-voltage transmission conductor, and communication optical fiber. The cable outer diameter is 5 to 6 mm, and the unit weight is ≤30 g / m. It connects the ground power supply 7 and the electrical load 19. Under normal operating conditions, the ground power supply 7 supplies the electrical load 19 at full power through the photoelectric composite tether cable 6, and the electrolysis equipment 18 serves as a hydrogen reserve supplement. When the photoelectric composite tether cable 6 is normally connected, the ground power supply 7 serves as the main power supply circuit, the fuel cell 15 serves as the emergency backup power supply in case of cable failure, and the energy storage battery 17 serves as the onboard uninterruptible power supply (UPS). In the event of an accidental breakage of the photoelectric composite tether cable 6, the energy storage battery 17 instantly provides power, and the fuel cell 15 starts to take over the power supply within a short time. Simultaneously, the auxiliary airbag 13 is inflated to increase weight, achieving a safe forced landing, thus forming a three-level redundant power supply architecture of ground power supply 7—fuel cell 15—energy storage battery 17.

[0093] Example 9: Modular high-altitude splicing base In this embodiment, the airship 8 serves as the airship module 9, such as Figure 4As shown, multiple airship modules 9 are assembled in a cryogenic airspace. Taking a spherical airship module 9 with a diameter of 30m as an example, the geometric thickness of its continuous ice shielding layer 4 is controlled within 1.8mm. High-concentration SAP water-absorbing sealing strips 11 are pre-embedded at the splicing edges of the airship modules 9. After ascending to a cryogenic airspace of 4000m, multiple airship modules 9 are assembled on-site. Water vapor at the gaps sublimates and freezes on the surface of the water-absorbing sealing strips 11, forming an adhesive-free ice-bonded connection layer 10, which fixes each airship module 9 into an integral high-altitude base. The tensile load per unit width of a single joint is not less than 200N / m, and the joint and the ice layer of the skin also have the ability to self-heal due to deformation. The scattered airship modules 9 are thus solidified into an integrated high-altitude platform.

[0094] Example 10: Adaptive Control Technology for Ice Layer Thickness The relationship between water injection per unit area of ​​hydrogen barrier sealing skin, flight altitude, ambient temperature, and stationary flight time and icing thickness was pre-calibrated: for a stationary flight condition of 3000m, -10℃, and 7 days, the water injection per unit area of ​​hydrogen barrier sealing skin was 1.2L / m², taking into account the water storage thickness and expansion rate of the porous support, with an icing thickness of approximately 1.5mm; for a long-haul flight condition of 5500m, -25℃, and 30 days, the water injection per unit area of ​​hydrogen barrier sealing skin was 4.0L / m², with an icing thickness of approximately 6.0mm; water was precisely injected according to the calibration data before takeoff, so that the icing thickness could be controlled as needed.

[0095] Example 11: Ice thickness grading and buoyancy verification This embodiment presents an adaptive ice thickness control process: The relationship between water injection volume per unit area of ​​the hydrogen-barrier sealing skin, flight altitude, ambient temperature, dwell time, and ice thickness is pre-calibrated. Water is precisely injected before takeoff according to the calibration data, achieving on-demand control of ice thickness. Water injection volume per unit area q (L / The conversion relationship between the geometric thickness t (mm) of the continuous ice shielding layer 4 and the geometric thickness t (mm) is as follows: ,in, The density of liquid water, =0.917g / The density of ice, Porosity of the porous support. =75% (based on water injection 1.0L / ) The corresponding ice layer geometric thickness is approximately 1.5mm, 1.25L / Corresponding to approximately 1.8mm, 1.7L / Corresponding to approximately 2.5mm, 2.05L / Corresponding to approximately 3.0mm; in high-altitude, low-humidity environments, the sublimation of external water vapor on the ice surface can increase the actual ice thickness by 5% to 10% compared to the water injection conversion value. Calibration is based on actual measured data. Typical operating condition calibration values: 9 modules of a 30m diameter airship, 3000m altitude, -10℃, 7-day stationary operation, water injection per unit area 1.0L / The ice layer has a geometric thickness of approximately 1.5mm; for the same type of module, at an altitude of 5000m, at -20℃, and under 30-day long-term operating conditions, the water injection per unit area is 1.25L / m². The geometric thickness of the ice layer is approximately 1.8 mm; =0.12 Large airships (such as spheres with a diameter of 50m), capable of long-range operation at 5000m, with a water injection capacity of 1.7L / unit area. The geometric thickness of the ice layer is approximately 2.5 mm.

[0096] Buoyancy check constraint: The proportion of the mass of the continuous ice shield layer 4 to the net buoyancy of the airship 8 Where A is the outer surface area of ​​the main airbag 12, and V is the volume of the main airbag 12. The density difference between air and hydrogen at the stationary altitude; spherical aerostat 8 =3 / r, where r is the radius of the spherical aerostat 8, which is the streamlined hull. Based on the actual shape, the hull has a length-to-slenderness ratio of 3:1. It is approximately 1.15 to 1.20 times the density of a sphere of the same volume. (Based on the density of ice) =0.917g / Porosity of porous support =75% calculation: For a 30m diameter airship module 9 ( =0.2 At a height of 5000m, Δρ≈0.68kg / An ice layer geometric thickness of 1.8 mm corresponds to η≈36%, which provides sufficient buoyancy margin for the structure's self-weight and mission load. If the ice layer geometric thickness exceeds the limit (e.g., 4.0 mm for a 30m-class module), η reaches approximately 81%, making it essentially unable to bear the effective mission load. Therefore, the ice layer geometric thickness of the 30m-class airship module 9 should be limited to within 1.8 mm. =0.15 For an airship 8 (such as a sphere with a diameter of 40m), the geometric thickness of the ice layer is 2.5mm, corresponding to η≈38% at an altitude of 5000m; for No greater than 0.12 The large airship 8, with an ice layer geometric thickness of 3.0 mm, corresponds to η≈36% at a height of 5000m, which satisfies the buoyancy constraint of η≤0.4.

[0097] Example 12: Triple Self-Healing Mechanism of Ice Layer According to publicly available literature (Patterson and Saltzman, J. Geophys. Res. Atmos., 2021), the permeability of ice Ih to hydrogen in the temperature range of 199 to 253 K is approximately The order of magnitude, converted to a volume unit of approximately The invention utilizes the high-altitude, low-temperature environment of the airship 8 to generate a continuous thin ice layer in situ within the porous framework of the inner layer of the hydrogen-blocking sealing skin. The dense hydrogen bond network of the ice forms a physical hydrogen-blocking barrier, which, in conjunction with the airtight isolation layer 2, achieves highly efficient hydrogen-blocking sealing. Based on an estimated geometric thickness of 1.8 mm for the continuous ice shielding layer 4 and a pressure difference of 500 Pa between the inside and outside of the capsule, the hydrogen permeation flux is as low as... The scale is negligible, and the annual penetration rate per boat is negligible.

[0098] The theoretical basis of the triple self-healing mechanism of ice is as follows: First, (confined compressive stress closure): within the confinement of a 75% porosity polyurethane porous support, the freezing expansion of the ice layer is constrained by the pores of the skeleton, generating pre-compressive stress. According to the principle of pre-compressive stress driving crack closure in solid mechanics, the pre-compressive stress can drive the crack surface to close after crack formation, restoring the seal. Second, (stress-induced compressive melting-recrystallization welding): the deformation of the capsule generates local stress concentration. Based on the principle of pressure reducing freezing point described by the Clapeyron equation, the ice crystals in the local high-pressure area melt. Water fills the cracks and gaps, and after stress release, the water recrystallizes and welds the cracks. This pressure-melt-recrystallization mechanism has been systematically described in glacier mechanics literature. When the ice layer thickness is 2 mm and the radius of curvature of the bladder is 5 m, the bending stress can reach the local pressure-melt condition of the ice body, realizing stress-induced melting and welding. The third stage (sublimation-deposition cross-crack migration and densification) is that ice crystals at the crack edge sublimate in low temperature and low humidity environment, and water vapor migrates to the low temperature region and condenses and deposits, completing the densification and reconstruction of ice crystals across the crack. The sublimation-deposition mass transfer process has been reported in literature in porous media ice bodies.

[0099] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and all such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A hydrogen-barrier sealing skin, characterized in that, It includes a water storage layer, an airtight isolation layer, and a protective outer layer arranged sequentially from the inside out; The water storage functional layer includes a water-absorbing polymer and a porous support. The water-absorbing polymer is used to adsorb and retain liquid water under normal temperature conditions, and the porous support is used to provide storage space and a freezing confinement environment for the liquid water. When the ambient temperature drops below 0°C, the liquid water held in the water storage layer freezes in situ in the pores of the porous support, forming a continuous ice shielding layer that interpenetrates with the porous support. The continuous ice shielding layer and the airtight isolation layer together form a sealed barrier structure against hydrogen.

2. The hydrogen-barrier sealing skin according to claim 1, characterized in that, The porous support is configured to apply confined compressive stress to the ice body when the liquid water freezes in situ, so that the continuous ice shielding layer has the ability to self-heal when microcracks are generated.

3. The hydrogen-barrier sealing skin according to claim 2, characterized in that, The self-healing ability includes a triple mechanism: confined compressive stress closure, stress-induced compressive melting-recrystallization welding, and sublimation-condensation densification across crack migration.

4. The hydrogen-barrier sealing skin according to claim 1, characterized in that, The water-absorbing polymer has a water retention rate of not less than 95% after standing for 24 hours under a 10 kPa compressive load and 25°C. The porosity of the porous support is 60% to 85%.

5. The hydrogen-barrier sealing skin according to claim 1, characterized in that, The outer surface of the protective outer layer is coated with a photovoltaic film, and the anti-ultraviolet encapsulation layer on the surface of the photovoltaic film together with the protective outer layer constitutes a dual ultraviolet protection structure.

6. An airship, characterized in that, include: The main airbag, wherein the airbag wall is made of hydrogen-blocking sealing skin as described in any one of claims 1 to 5, and the main airbag is filled with hydrogen. The electrical load is located inside the main airbag; A fuel cell for converting the hydrogen into electrical energy to supply the electrical load; The waste heat generated by the electrical load and / or the fuel cell during operation is transferred to the continuous ice shielding layer of the main airbag through the natural convection of hydrogen gas inside the main airbag, and dissipated by the phase change heat absorption of the continuous ice shielding layer.

7. The airship according to claim 6, characterized in that, It also includes a secondary airbag connected to but not in communication with the main airbag. The secondary airbag is connected to an air pump and a valve for inflating or deflating air from the outside to adjust the buoyancy balance of the airship.

8. The airship according to claim 6, characterized in that, The cathode side of the fuel cell is connected to the outside atmosphere through an independent pipeline, and the anode side is connected to the hydrogen in the main gasbag. The cathode side and the anode side are physically isolated from each other. During operation, the hydrogen in the main gasbag and the outside air are used as raw materials, and the generated by-product water is guided to the water storage tank through the recovery pipeline.

9. The airship according to claim 6, characterized in that, The outer surface of the protective outer layer is coated with a photovoltaic power generation film. The electrical energy generated by the photovoltaic power generation film is used to supply the electrical load and to electrolyze the by-product water in the water storage tank. The oxygen generated after the by-product water is electrolyzed is discharged to the outside, and the hydrogen generated is introduced into the main airbag.

10. The airship according to claim 6, characterized in that, It also includes an energy storage battery, which is a low-temperature sodium-ion battery or a modified lithium-ion battery, used for powering the equipment to start up in low-temperature environments and for smoothing and compensating for instantaneous power fluctuations of the electrical load.

11. The airship according to claim 10, characterized in that, It also includes an optoelectronic composite tethered cable connecting to the ground base station; when the optoelectronic composite tethered cable is normally connected, the ground power supply serves as the main power supply circuit, the fuel cell serves as the emergency backup power supply in case of cable failure, and the energy storage battery serves as the uninterrupted backup power supply.

12. The airship according to claim 6, characterized in that, The electrical load is encapsulated in a sealed metal container with heat dissipation fins. The metal container is suspended in the internal space of the main airbag, physically isolating the electrical load from the hydrogen gas inside the main airbag.

13. The airship according to claim 6, characterized in that, The airship is an airship module, and multiple airship modules are spliced ​​together in a low-temperature airspace to form an integral high-altitude base; water-absorbing sealing strips are provided at the splicing edges of adjacent airship modules, and adjacent airship modules rely on water vapor sublimation and ice formation in a low-temperature environment to form an ice-bonded connection layer, which fixes each airship module into a whole.

14. The airship according to claim 6, characterized in that, The geometric thickness t of the continuous ice shielding layer and the porosity of the porous support The surface area to volume ratio of the main airbag Satisfying buoyancy constraints: That is, the mass of the continuous ice shielding layer does not exceed 40% of the net buoyancy of the airship; where A is the outer surface area of ​​the main airbag, V is the volume of the main airbag, and t is the geometric thickness of the continuous ice shielding layer as an ice-skeleton composite layer. The density of ice, The difference between the air density and hydrogen density at the stationary altitude; for the surface area to volume ratio Not less than 0.2 For the airship, the geometric thickness of the continuous ice shield does not exceed 1.8 mm; At 0.12 Up to 0.15 For airships within a certain range, the geometric thickness of the continuous ice shield does not exceed 2.5 mm; No greater than 0.12 For large airships, the geometric thickness of the continuous ice shield layer does not exceed 3.0 mm.

15. A hydrogen-blocking sealing method for an airship, wherein the main gasbag wall of the airship is made of a hydrogen-blocking sealing skin as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Liquid water is adsorbed and sealed in the water storage layer of the hydrogen-barrier sealing skin on the ground; The airship is raised to an airspace below 0°C, causing the liquid water in the water storage functional layer to freeze in situ in the pores of the porous support, forming a continuous ice shielding layer. The continuous ice shielding layer and the airtight isolation layer are used together to block hydrogen gas.

16. The method according to claim 15, characterized in that, It also includes a heat dissipation step: the waste heat generated by the airship's electrical load and / or fuel cell is transferred to the continuous ice shielding layer through the natural convection of hydrogen in the main airbag, and dissipated by the phase change heat absorption and melting of the continuous ice shielding layer; after the ambient temperature drops, the melted water is re-frozen in the porous support body.

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