Static thermoelectric power system based on deep-sea hydrothermal vents

Abstract

The application discloses a static thermoelectric power supply system based on a deep-sea hot spring, and relates to the technical field of deep-sea power supply.The system is arranged in a deep-sea hot spring area and comprises a primary heat pipe heat absorption and transmission module, a thermoelectric power generation core module, a secondary cascade heat pipe heat dissipation module, a pressure protection module, a heat pipe protection and flow guide module and a power management module.The primary heat pipe heat absorption and transmission module adopts a pressure-resistant and corrosion-resistant gravity heat pipe to collect hot spring heat energy and transmit the heat energy to the thermoelectric power generation core module; the thermoelectric power generation core module adopts a thermoelectric power generation sheet array to convert the heat energy into electric energy; the secondary cascade heat pipe heat dissipation module discharges cold end waste heat to deep-sea seawater; the pressure protection module isolates seawater from a high-pressure environment; and the heat pipe protection and flow guide module realizes heat collection end protection and flow field optimization of the heat dissipation end.The application solves technical problems such as deep-sea high-pressure yield resistance, loose connection of dissimilar metals at high temperatures and deep-sea high-efficiency heat dissipation, and provides long-term in-situ power supply for deep-sea unmanned underwater vehicles, Internet of Things sensors and other equipment.

Description

Technical Field

[0001] This invention relates to the field of deep-sea power supply technology, and more specifically, to a static thermoelectric power supply system based on the utilization of deep-sea hydrothermal energy, which is particularly suitable for long-term in-situ power supply of equipment such as deep-sea unmanned submersibles, underwater autonomous operation platforms, deep-sea environmental monitoring sensor networks, and deep-sea Internet of Things nodes. Background Technology

[0002] With the continuous enhancement of the strategic importance of the marine economy and the rapid development of deep-sea exploration technology, human activities in the exploration, development, and scientific research of deep-sea resources are becoming increasingly frequent. Deep-sea unmanned underwater vehicles, seabed observation network nodes, underwater environmental monitoring sensors, and deep-sea geological exploration equipment have become core equipment in fields such as marine resource exploration, seabed geological research, marine environmental monitoring, and national defense security. Long-term stable power supply for such equipment in the extreme environment of the deep sea is a fundamental prerequisite for ensuring its long-term autonomous underwater operation and achieving continuous data acquisition and transmission.

[0003] Currently, the aforementioned deep-sea equipment generally uses chemical batteries (such as lithium-ion batteries and silver-zinc batteries) as its main power source. This power supply mode has revealed several insurmountable technical challenges in long-term engineering practice. First, chemical batteries have limited energy density. Constrained by the size and weight of deep-sea equipment, the total capacity of the battery packs is insufficient to meet the needs of long-term underwater operations. The continuous operating time of the equipment is typically only tens to hundreds of hours, severely limiting the operational duration and coverage of deep-sea exploration missions. Second, after the chemical batteries are depleted, the equipment needs to be recovered and brought ashore for charging or battery pack replacement using surface support vessels. This process not only consumes significant manpower and resources and increases operating costs, but also significantly reduces the in-situ operational efficiency and mission continuity of the equipment. Especially for equipment deployed in the deep sea, the cost and risk of frequent recovery are extremely high. Furthermore, the high pressure, low temperature, high salinity, and strong corrosive environment of the deep sea, including those containing sulfides, place extremely stringent requirements on the sealing, structural integrity, and electrochemical stability of chemical batteries. Batteries are prone to safety problems such as sealing failure, electrolyte leakage, internal short circuits, and even thermal runaway under long-term deep-sea high-pressure environments, making it difficult to guarantee their service reliability.

[0004] Meanwhile, deep-sea hydrothermal vents possess abundant and stable geothermal resources. The hydrothermal fluid temperature at the vents typically reaches 200–400°C, while the surrounding deep-sea water temperature remains constant at around 0–4°C. This creates a natural and stable temperature difference exceeding 200°C, providing ideal thermoelectric heat source conditions for thermoelectric power generation. Static thermoelectric power generation technology, based on the Seebeck effect, utilizes the thermoelectric properties of semiconductor thermoelectric materials to directly convert heat energy into electrical energy. This technology boasts significant advantages, including no moving parts, compact structure, quiet operation, extremely high reliability, long theoretical lifespan, and near-maintenance-free operation. It is considered one of the most promising technological pathways for solving the problem of long-term in-situ power supply for deep-sea equipment.

[0005] However, the engineering application of static thermoelectric power generation technology to the extreme environment of deep-sea hydrothermal vents still faces a series of severe technical challenges that need to be overcome. First, the high-pressure environment of the deep sea places extremely stringent requirements on the pressure-resistant structural design and material strength of the equipment. Ordinary metal materials are prone to plastic instability, crushing, or creep failure under such high pressure, necessitating the selection of high-strength, corrosion-resistant special materials supplemented by a reasonable pressure-bearing structural design. Second, deep-sea hydrothermal vents are rich in corrosive gases such as hydrogen sulfide and sulfur dioxide, as well as various metal ions, and have an acidic pH value, resulting in severe chemical corrosion and stress corrosion cracking of metal materials. Ordinary corrosion-resistant materials are insufficient to meet the requirements for long-term service, necessitating the selection of special corrosion-resistant materials. Third, while the huge temperature difference between the hydrothermal vent and seawater provides the thermodynamic driving force for power generation, achieving efficient heat energy harvesting, low heat loss transmission, and efficient heat dissipation into the seawater to establish and maintain a stable high-temperature difference between the hot and cold ends of the thermoelectric device is the core technical challenge for ensuring thermoelectric conversion efficiency. Fourth, the system components involve various dissimilar materials such as titanium alloys, copper, and thermoelectric materials. Under the high-temperature conditions of the hot spring, the thermal expansion coefficients of these materials differ significantly, which can easily lead to loosening, cracking, or a sharp increase in contact thermal resistance at the connection interface, seriously affecting the system's heat transfer efficiency and long-term operational stability.

[0006] Currently, most research reports on deep-sea thermoelectric power sources at home and abroad remain at the theoretical analysis stage. Existing technical solutions generally suffer from prominent problems such as low output power, insufficient structural pressure and corrosion resistance, lack of engineering protection design for the complex flow field environment of deep-sea hydrothermal vents, and difficulty in achieving stable output of kilowatt-level high power. They are still far from meeting the actual power requirements of deep-sea equipment, and their feasibility for engineering application is low.

[0007] In view of this, developing a static thermoelectric power supply system that can adapt to the high-pressure and highly corrosive environment of deep-sea hydrothermal vents, achieve high-power stable thermoelectric conversion output, has a long lifespan, high reliability, and high engineering feasibility is of great practical significance and far-reaching strategic value for promoting the leapfrog development of power supply technology for deep-sea equipment and supporting my country's deep-sea resource exploration and scientific research. Summary of the Invention

[0008] The purpose of this invention is to overcome the technical defects of existing deep-sea equipment powered by chemical batteries, such as insufficient endurance, high maintenance costs, and poor adaptability to the deep-sea environment. At the same time, it solves the prominent problems of existing deep-sea thermoelectric power supply technology, such as low output power, poor structural reliability, and lack of engineering protection design, and provides a static thermoelectric power supply system based on deep-sea hydrothermal vents.

[0009] This invention aims to utilize the significant natural temperature difference between the stable hydrothermal vents and the low-temperature seawater in deep-sea hydrothermal vent areas. Based on the principle of static thermoelectric conversion, it achieves efficient, stable, and long-term conversion of thermal energy from deep-sea hydrothermal vents into electrical energy, providing an in-situ power supply solution that meets the power requirements of equipment such as deep-sea unmanned submersibles, underwater sensor networks, and deep-sea IoT nodes. This invention will focus on solving key technical challenges such as structural yield resistance and sealing protection under high-pressure deep-sea environments, material corrosion resistance selection under corrosive deep-sea environments, thermal expansion mismatch and contact thermal resistance control at high-temperature interfaces of dissimilar metals, efficient heat collection and dissipation in deep-sea hydrothermal vent environments, and erosion and wear protection of the heat collection end. Ultimately, it achieves efficient utilization of deep-sea hydrothermal energy, providing deep-sea equipment with a long-term, stable, and maintenance-free power supply that meets power requirements, while also possessing modular expansion capabilities to adapt to complex application scenarios.

[0010] To achieve the above objectives, the present invention provides the following solution:

[0011] This invention provides a static thermoelectric power system based on deep-sea hydrothermal vents, deployed in a deep-sea hydrothermal vent area. It includes a primary heat pipe heat absorption and transfer module, a thermoelectric power generation core module, a secondary cascaded heat pipe heat dissipation module, a pressure protection module, and a power management module. The primary heat pipe heat absorption and transfer module uses pressure-resistant and corrosion-resistant gravity heat pipes to collect thermal energy from the deep-sea hydrothermal vents and transfer it to the thermoelectric power generation core module. The thermoelectric power generation core module includes an array of multiple thermoelectric generators, converting thermal energy into electrical energy based on the Seebeck effect. The secondary cascaded heat pipe heat dissipation module consists of a thermally conductive cold plate and pressure-resistant and corrosion-resistant secondary heat pipes, used to discharge waste heat from the cold ends of the thermoelectric generators into the deep-sea seawater. The pressure protection module uses a sealed shell made of pressure-resistant and corrosion-resistant materials to enclose the thermoelectric power generation core module and the power management module, isolating them from seawater and the high-pressure environment. The power management module is used to achieve stable storage and output of electrical energy.

[0012] Preferably, the gravity heat pipe of the primary heat pipe heat transfer module is a primary heat pipe, which is divided into an evaporation section, a transition section and a condensation section along its length. The evaporation section uses longitudinal fins formed by integrated hot extrusion to expand the heat collection area. The condensation section has its fins removed and its wall thickness reduced by machining. The transition section has a smooth transition in wall thickness achieved by slope processing and is covered with heat insulation material. The primary heat pipe is filled with high-purity degassed water as a phase change heat transfer medium.

[0013] Preferably, the core module for thermoelectric power generation also includes a heat-conducting column, which is made of a high thermal conductivity metal material and is used to evenly distribute the heat energy transmitted by the primary heat pipe to the hot end of each thermoelectric power generation unit. The heat-conducting column has an installation through hole, and the condensation section of the primary heat pipe passes through the installation through hole. The condensation section and the installation through hole are connected by an interference fit through a hydraulic expansion process to maintain residual contact pressure at the interface to compensate for the thermal expansion difference of dissimilar materials under high temperature conditions.

[0014] Preferably, an indium foil is provided between the outer wall of the condensation section and the inner wall of the mounting through hole to fill the micro gaps at the interface and reduce the contact thermal resistance; thermal grease is applied between the hot end face of the thermoelectric generator and the heat-conducting square pillar, and between the cold end face of the thermoelectric generator and the heat-conducting cold plate.

[0015] Preferably, the heat-conducting cold plate of the two-stage cascaded heat pipe heat dissipation module is a copper cold plate, which is attached to the cold end face of the thermoelectric generator to collect waste heat and achieve uniform temperature at the cold end; the secondary heat pipe is a gravity-type heat pipe, which has a sintered core and is filled with high-purity ammonia as the heat transfer medium. One end of the secondary heat pipe is thermally connected to the copper cold plate, and the other end extends into the deep seawater to discharge waste heat into the seawater.

[0016] Preferably, the wall material of the primary heat pipe and the secondary heat pipe, as well as the sealing shell material of the pressure protection module, are selected from one or more of TA2 pure titanium, TC4 titanium alloy, Gr7 titanium alloy, or nickel-based alloy; the sealing shell adopts a composite sealing structure combining atmospheric pressure sealing and potting sealant sealing.

[0017] Preferably, it also includes a heat pipe protection and flow guiding module, which includes a primary heat pipe protection shield and a secondary heat pipe hyperbolic flow guiding shield. The primary heat pipe protection shield covers the outside of the evaporation section of the primary heat pipe heat absorption and transfer module and is made of pressure-resistant and corrosion-resistant alloy to resist the impact of deep-sea hydrothermal vents and abrasion from sand and gravel. The secondary heat pipe hyperbolic flow guiding shield is set on the outside of the heat dissipation section of the secondary heat pipe, and its flow channel profile is hyperbolic to optimize seawater convection heat transfer, improve heat dissipation efficiency, and reduce fluid resistance.

[0018] Preferably, the thermoelectric generator uses a medium-high temperature thermoelectric generator with solder replacement, electrode anti-oxidation coating and encapsulation structure reinforcement to adapt to the high temperature and high pressure working conditions of deep-sea hydrothermal vents; the array of thermoelectric generators consists of multiple thermoelectric generators evenly arranged around the heat-conducting square column and electrically connected by series and / or parallel combination.

[0019] Preferably, the system has a modular expansion structure, with each system being a unit module. Each unit module is equipped with mechanical installation interfaces and electrical parallel connection interfaces that can be expanded and linked. Multiple unit modules can be combined and connected in parallel through the mechanical installation interfaces and electrical parallel connection interfaces to achieve on-demand multiplication of the total output power.

[0020] Preferably, the system is designed with a net output power ≥1000W, a temperature difference between the hot and cold ends of the thermoelectric generator ≥200℃, and a structural safety factor ≥7 for the primary and secondary heat pipes.

[0021] The present invention achieves the following technical effects compared to the prior art:

[0022] 1. This invention achieves long-term, in-situ power supply for deep-sea equipment, completely eliminating the bottleneck of chemical battery endurance. Utilizing the continuous temperature difference between deep-sea hydrothermal vents (a natural, stable heat source) and deep-sea low-temperature seawater geothermal traps, this invention achieves continuous in-situ power generation through static thermoelectric conversion technology, eliminating the need for surfacing for recharging or battery replacement throughout its entire lifespan. Compared to existing chemical battery power supply methods, this invention fundamentally solves the problem of limited endurance for deep-sea equipment due to difficulties in power replenishment. It can significantly extend the in-situ operating time of deep-sea unmanned underwater vehicles and seabed observation networks, significantly reduce the frequency of recovery and recharging operations and maintenance costs, and provide a reliable basic power supply guarantee for long-term continuous deep-sea exploration and real-time monitoring.

[0023] 2. The system boasts high output power and excellent thermoelectric conversion efficiency, meeting the actual power requirements of deep-sea equipment. This invention constructs a complete and efficient heat-to-electric conversion link through a technical architecture design of "high-efficiency heat collection and transfer via a primary gravity heat pipe + stable conversion via a static thermoelectric array + enhanced heat dissipation via a secondary cascaded heat pipe," achieving a temperature difference of >200℃ between the hot and cold ends of the thermoelectric generator. Compared to existing deep-sea thermoelectric power sources, this invention achieves a significant leap in output power, advancing deep-sea hydrothermal vent thermoelectric power generation technology to the kilowatt-level engineering application level for the first time, effectively meeting the actual power requirements of deep-sea operational equipment.

[0024] 3. The system exhibits excellent long-term reliability and safety under extreme deep-sea pressure and corrosion environments. This invention uses pressure-resistant and corrosion-resistant materials as the core structural material of the heat pipe, possessing resistance to deep-sea sulfide corrosion and high strength. Combined with structural design and pressure protection modules and heat pipe protection and flow guiding modules, it can withstand deep-sea pressure and impact, solving technical challenges such as yielding resistance and corrosion failure under deep-sea pressure. The structure has a sufficient safety factor, a high strength safety factor during stable operation, and is resistant to seawater corrosion, adapting to the complex deep-sea environment.

[0025] 4. Effectively solves the problem of thermal expansion mismatch at high-temperature interfaces of dissimilar metals. This invention innovatively employs a hydraulic expansion process to achieve dissimilar metal connection between titanium alloy heat pipes and copper heat-conducting square pillars. By precisely controlling the expansion pressure during the expansion process, the residual contact pressure maintained at the interface can effectively compensate for the interface separation tendency caused by the difference in thermal expansion coefficients between titanium alloy and copper under subsequent high-temperature service conditions above 200°C, ensuring tight contact and stable low thermal resistance throughout the entire service temperature range. This technical solution fundamentally solves the technical problem of loosening at high-temperature interfaces of dissimilar metals that has plagued the field of deep-sea thermoelectric power supplies. The process is mature, highly controllable, and consistent, making it feasible for industrial-scale mass production.

[0026] 5. High engineering feasibility and self-controllable supply chain. The core materials involved in this invention—titanium alloy heat pipes, bismuth telluride thermoelectric generators, copper heat-conducting square columns and cold plates, hydraulic expansion joint equipment, DC-DC conversion modules, etc.—are all non-standard products that are routinely procured in the domestic industrial sector or have mature production processes. The supply chain is complete, and there is no risk of being dependent on foreign countries for core materials. The modular design of the system keeps the total weight of a single system under 500 kg, allowing for underwater transport, positioning, installation, and disassembly and maintenance using existing commercial deep-sea ROVs, without relying on large surface support vessels or manual diving operations. The technical solution proposed in this invention has good compatibility with the power supply interfaces of existing deep-sea equipment, enabling rapid engineering application without significant modifications to the equipment itself. The technical threshold and cost for widespread implementation are both within a reasonable and controllable range.

[0027] 6. It possesses flexible modular expansion capabilities to adapt to diverse power requirements. This invention features standardized mechanical installation interfaces and electrical parallel connection interfaces. Users can combine and connect multiple basic units in parallel according to the power requirements of deep-sea equipment or observation networks, achieving on-demand doubling of total output power. The expanded multi-module system still operates under the coordination of a unified power management network, requiring no modifications to the design and manufacturing of the basic modules. Expansion costs are controllable, and the technical approach is clear. This feature enables the invention to flexibly adapt to a wide range of power supply requirements, from individual deep-sea sensor nodes to large unmanned underwater vehicles or seabed observation base stations, possessing broad application prospects and market promotion value. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1This is a schematic diagram of the overall structure of the static thermoelectric power supply system based on deep-sea hydrothermal vents of the present invention;

[0030] Figure 2 This is a detailed schematic diagram of the power generation module of the static thermoelectric power system based on deep-sea hydrothermal vents of the present invention;

[0031] Figure 3 This is a schematic diagram of the primary heat pipe structure in this invention;

[0032] Figure 4 This is a schematic diagram of the cross-section of the secondary heat pipe in this invention.

[0033] In the picture:

[0034] 1. Second-stage cascaded heat pipe cooling module; 2. Second-stage heat pipe hyperbolic flow guide shroud; 3. Power management module; 4. Pressure protection module; 5. Thermoelectric power generation core module; 6. Primary heat pipe protective cover; 7. Primary heat pipe heat absorption and transfer module; 8. Second-stage heat pipe; 9. Copper cold plate; 10. Thermoelectric power generation plate; 11. Copper square column; 12. Primary heat pipe; 13. Condensation section; 14. Transition section; 15. Evaporation section; 16. Heat pipe outer wall; 17. Sintered core. Detailed Implementation

[0035] 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, and 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.

[0036] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Example: Kilowatt-level static thermoelectric power supply system

[0038] This embodiment provides a kilowatt-level static thermoelectric power supply system based on deep-sea hydrothermal vents. The system is deployed in a deep-sea hydrothermal vent area at a depth of approximately 2000m, using high-temperature hydrothermal fluid (measured temperature approximately 300℃) as the heat source and surrounding deep-sea seawater at approximately 4℃ as the cold trap, achieving a continuous net electrical power output of no less than 1000W. The following is in conjunction with… Figures 1 to 4 The structural diagram shown provides a complete description of the system's specific composition, detailed parameters of each component, working process, and performance.

[0039] I. Overall System Composition

[0040] like Figure 1As shown, the static thermoelectric power system based on deep-sea hydrothermal vents in this embodiment mainly includes: a primary heat pipe heat absorption and transmission module 7, a thermoelectric power generation core module 5, a secondary cascaded heat pipe heat dissipation module 1, a pressure protection module 4, a heat pipe protection and flow guiding module (including a primary heat pipe protection cover 6 and a secondary heat pipe hyperbolic flow guiding cover 2), and a power management module 3. The modules are arranged sequentially in space according to the direction of heat flow: the primary heat pipe heat absorption and transfer module 7 is located at the front end, with its evaporation section 15 extending into the hydrothermal vent area; the thermoelectric power generation core module 5 is located in the middle, connected to the condensation section 13 of the primary heat pipe 12 via a copper square column 11; the secondary cascaded heat pipe heat dissipation module 1 is located at the rear end, with its copper cold plate 9 attached to the cold end face of the thermoelectric power generation plate 10, and the secondary heat pipe 8 extending from the copper cold plate 9 to the surrounding seawater; the pressure protection module 4 encloses the thermoelectric power generation core module 5 and the power management module 3 inside a sealed shell; the primary heat pipe protective cover 6 covers the outside of the evaporation section 15, and the secondary heat pipe hyperbolic flow guide shroud 2 is located on the outside of the heat dissipation section of the secondary heat pipe 8.

[0041] II. Specific Structure and Parameters of Each Component

[0042] 1. Primary heat pipe heat absorption and transfer module 7

[0043] like Figure 1 and Figure 3 As shown, the primary heat pipe heat transfer module 7 includes five independent gravity heat pipes (i.e., primary heat pipes 12). Each heat pipe is divided into an evaporation section 15, a transition section 14, and a condensation section 13 along its length. The parameters of each component are as follows:

[0044] (1) Material and specifications of the heat pipe base tube: TA2 pure titanium seamless tube is selected. This material has excellent corrosion resistance in deep-sea hydrothermal vents containing sulfides and can still maintain sufficient mechanical strength at a high temperature of 300℃. The outer diameter of the base tube is 20.0mm and the nominal wall thickness is 2.5mm. To resist the combined effects of underwater depth of 2000m and hydrothermal vent scouring, after strength verification, the circumferential stress of this wall thickness at 300℃ is 34.09MPa, which is far lower than the yield strength of TA2 pure titanium at 300℃. The safety factor reaches 7.04, meeting the requirements for long-term safe service.

[0045] (2) Evaporation section 15: 1000 mm in length. The outer wall of evaporation section 15 is formed with longitudinal fins by an integrated hot extrusion process. The fins have 24 teeth, with a tooth height of 6.0 mm and a tooth thickness of 1.0 mm. The tooth spacing is uniform and they are evenly distributed around the circumference of the pipe wall. This integrated forming process ensures that the fins and the base pipe are metallurgically bonded, with no contact thermal resistance and high heat transfer efficiency. The design of the longitudinal fins greatly expands the external heat exchange area of ​​evaporation section 15, effectively compensating for the shortcomings of the low axial flow velocity and low convective heat transfer coefficient of the deep-sea hydrothermal vent along the pipe wall.

[0046] (3) Condensing section 13: 300mm in length. The original longitudinal fins of the condensing section 13 are removed by machining, and the outer diameter is precision machined from 20.0mm to 18.0mm, with the wall thickness correspondingly reduced to 1.5mm. The thinning process shortens the radial conduction path of heat from the vapor in the tube cavity to the outer wall surface, effectively reducing the thermal resistance of the tube wall. The outer diameter of the condensing section 13 is precision machined to form a precise clearance fit with the mounting through hole on the subsequent copper square column 11, providing accurate initial assembly dimensions for the hydraulic expansion connection process.

[0047] (4) Transition section 14: 150 mm in length. The transition section 14 is located between the evaporation section 15 and the condensation section 13. It retains the original fin structure and achieves a smooth transition in wall thickness from 2.5 mm in the evaporation section 15 to 1.5 mm in the condensation section 13 through a 30 mm slope. The slope angle of the wall thickness change area is about 1.9°, which is a low-stress, gradually changing structure. The exterior of the transition section 14 is covered with a heat insulation material layer to significantly reduce the radial heat conduction and heat radiation loss of high-temperature steam to the surrounding low-temperature seawater through the pipe wall during transmission, ensuring that the steam arrives at the condensation section 13 at a temperature of not less than 280°C.

[0048] (5) Internal working fluid of the heat pipe: Each primary heat pipe 12 is filled with high-purity degassed water as the phase change heat transfer working fluid, with a purity ≥99.999%. Before filling, the inside of the heat pipe is subjected to strict vacuum degassing treatment, and then high-purity water with precise measurement is injected. The filling amount is determined according to the internal volume of the heat pipe and the design operating temperature to ensure that the heat pipe has the best gas-liquid phase volume ratio within the set operating temperature range, and to avoid overfilling which would obstruct the steam flow or underfilling which would cause the evaporation section to dry out.

[0049] 2. Core Module 5 for Thermal Power Generation

[0050] like Figure 1 and Figure 2 As shown, the core module 5 for thermoelectric power generation includes a copper square pillar 11 (thermal conductive pillar), a thermoelectric power generation plate 10, and an interface thermal resistance optimization component (indium foil and thermal paste). Specific parameters are as follows:

[0051] (1) Copper square column 11: Made of T2 copper (purity ≥99.9%), the square column has an outer dimension of 50mm×50mm×300mm. Five axial through holes with a diameter of 18.0mm are opened along the central axis of the square column. The five through holes are arranged in a single row with equal spacing on the cross-section of the square column, with a hole spacing of 10mm, corresponding to the condensation section 13 of the five primary heat pipes 12. Copper has an extremely high thermal conductivity, which can quickly diffuse the heat released by the condensation section 13 in three dimensions along the volume of the square column, making the temperature distribution on the four sides of the square column tend to be uniform. The four 50mm wide sides of the square column are the mounting surfaces of the thermoelectric generator 10. The mounting surfaces are precision milled to ensure a tight fit with the hot end face of the thermoelectric generator 10.

[0052] (2) Hydraulic expansion connection process: After the condensing section 13 of the primary heat pipe 12 passes through the axial through hole of the copper square column 11, the two are connected by an interference fit using a hydraulic expansion connection process. The specific process parameters are as follows: inject pressure-transmitting liquid into the primary heat pipe 12, seal the pipe opening, apply an internal liquid pressure of 260 MPa, and hold the pressure for 15 to 30 seconds. Under this ultra-high hydraulic pressure, the TA2 titanium alloy tube wall of the condensing section 13 undergoes controllable radial plastic expansion deformation, forming a radial interference with the inner wall of the mounting through hole of the copper square column 11. After unloading the hydraulic pressure, the elastic recovery of the titanium alloy tube wall is less than that of the copper through hole wall, forming a residual contact pressure at the interface between the two. Under the subsequent high-temperature service conditions of 300℃, this residual contact pressure can effectively compensate for the interface separation tendency caused by the thermal expansion difference between the titanium alloy heat pipe and the copper square column, ensuring that the interface always maintains tight contact throughout the entire service temperature range. Compared with traditional mechanical expansion or thermal fitting, hydraulic expansion joint has outstanding advantages such as uniform interface pressure, high controllability, no damage to pipe wall, and suitability for thin-walled pipe connections.

[0053] (3) Interface thermal resistance optimization – Indium foil: A 0.1 mm thick high-purity indium foil is pre-insulated between the outer wall of the condenser section 13 of the primary heat pipe 12 and the inner wall of the mounting hole of the copper square column 11 before hydraulic expansion. Indium is extremely soft and undergoes sufficient plastic flow under the enormous pressure of hydraulic expansion, filling the microscopic unevenness of the two contact surfaces, thus significantly increasing the actual contact area and effectively reducing the additional contact thermal resistance caused by microscopic gaps. Actual measurements show that the interface contact thermal resistance can be controlled to 2 × 10⁻⁻⁶ after indium foil filling. 4 Within m²·℃ / W.

[0054] (4) Thermoelectric generator 10: A medium-high temperature bismuth telluride-based thermoelectric generator is selected, with a single unit size of 50mm×50mm×5.0mm.

[0055] In this embodiment, a total of 120 thermoelectric generators 10 are used, arranged in a mixed array of 6 series-connected and 20 parallel-connected arrays. The 120 thermoelectric generators 10 are arranged around the four sides of five copper square pillars 11, with 6 generators on each side, totaling 24 generators around each pillar, and 120 generators in total for the five pillars. This surrounding arrangement ensures uniform heat flow from the center of the pillars to the surrounding areas, resulting in good temperature uniformity at the hot end of the thermoelectric device and avoiding heat bypass losses.

[0056] (5) Interface thermal resistance optimization - thermal paste: Apply a layer of high thermal conductivity paste with a thickness of about 0.05 to 0.10 mm evenly between the hot end face of the thermoelectric generator 10 and the outer wall of the copper square column 11, and between the cold end face of the thermoelectric generator 10 and the copper cold plate 9.

[0057] 3. Two-stage cascaded heat pipe cooling module 1

[0058] like Figure 1 and Figure 4 As shown, the two-stage cascaded heat pipe cooling module 1 includes a copper cold plate 9 (thermal conductive cold plate) and two-stage heat pipes 8. Specific parameters are as follows:

[0059] (1) Copper Cold Plate 9: There are 20 copper cold plates 9 in total, made of T2 copper, each measuring 200mm×150mm×10mm. Five copper cold plates 9 are grouped together and attached to the cold end faces of the thermoelectric generators 10 arranged on the four sides of a copper square column 11. Each copper cold plate 9 maintains a constant contact pressure with the cold end face of the thermoelectric generator 10 through a pressing device to ensure a stable thickness of the thermal paste layer on the contact surface. The copper cold plate 9 quickly collects and homogenizes the waste heat discharged from the cold ends of each thermoelectric generator 10 through its high internal thermal conductivity, avoiding excessively high local temperatures at the cold ends.

[0060] (2) Secondary heat pipes 8: A total of 220 pipes, with 11 pipes evenly distributed on each copper cold plate 9. Each secondary heat pipe 8 has an outer diameter of 10mm, a wall thickness of 1.0mm, is made of TA2 pure titanium, and is 1.5m long. One end of each secondary heat pipe 8 forms good thermal contact with the copper cold plate 9 through brazing or mechanical clamping, while the other end extends outwards and is exposed to deep-sea water. Figure 4 As shown, the secondary heat pipe 8 has a sintered core 17 structure inside, which is made of copper-based spherical powder. The inner cavity of the secondary heat pipe 8 is filled with high-purity ammonia as the heat transfer medium.

[0061] 4. Pressure Protection Module 4

[0062] like Figure 1 As shown, the pressure protection module 4 is constructed using TA2 titanium alloy sheet (8mm thick) welded into a single sealed housing. The housing has a rectangular box structure, internally housing the copper square column 11, the electrical connection parts of the thermoelectric generator 10, the connection ends of the copper cold plate 9, and the circuit board of the power management module 3. The housing consists of an upper housing and a lower housing, connected by a flange with double O-ring seals on the flange mating surfaces. After assembly, the housing is filled with high-temperature epoxy resin potting compound, which has a certain thermal conductivity, dissipating a small amount of internal heat while simultaneously securing internal components and providing a secondary seal. A sealed through-structure is provided at the connection area between the outer wall of the housing and the copper square column 11 and the copper cold plate 9, using metal-glass sintered sealing terminals or ceramic sealing terminals to achieve through-insulation and sealing of the electrical leads.

[0063] 5. Heat pipe protection and flow guiding module

[0064] (1) Primary heat pipe protective cover 6: such as Figure 1As shown, the primary heat pipe protective cover 6 covers the evaporation section 15 and its longitudinal fins of the five primary heat pipes 12. The protective cover is made of TA2 titanium alloy sheet, stamped into a semi-cylindrical shell or rectangular structure, with a length of 1200mm. Multiple rows of elongated guide holes are evenly distributed on the surface of the cover, allowing the hot spring liquid to flow freely in and out, exchanging heat with the fins of the evaporation section 15. Simultaneously, it effectively blocks direct impact from sand and gravel particles larger than 3mm, protecting the fins from impact deformation or wear and thinning. The protective cover is fixedly connected to the wall of the primary heat pipe 12 via a bracket, making installation simple.

[0065] (2) Hyperbolic flow guide shroud 2 for secondary heat pipe: such as Figure 1 As shown, a hyperbolic flow deflector 2 for the secondary heat pipes is positioned outside the condensation sections of the 220 secondary heat pipes 8. The deflector is made of TA2 titanium alloy sheet, and its flow channel profile is hyperbolic, meaning that along the direction of seawater flow, the flow consists of a contraction section, a throat, and an expansion section, forming an overall Laval nozzle shape. The flow deflector confines the condensation sections of the 220 secondary heat pipes 8 within the flow channel inside the deflector. Seawater entering from the deflector inlet accelerates in the contraction section, enhancing convective heat transfer, and decelerates and regains pressure in the expansion section. Overall flow resistance is reduced by approximately 20%–30% compared to the state without the flow deflector. The deflector also protects the condensation sections of the secondary heat pipes 8 from external mechanical damage such as collisions with suspended matter in the surrounding currents or snagging by fishing nets.

[0066] 6. Power Management Module 3

[0067] like Figure 1 As shown, the power management module 3 is located inside the sealed housing of the pressure protection module 4. It includes a DC-DC boost / stabilization conversion circuit, a lithium battery pack, and an output protection circuit. It realizes the acquisition, voltage regulation, and stable storage of thermoelectric power generation energy. The output voltage is adapted to the needs of deep-sea equipment, supports overcharge and over-discharge protection, and ensures power supply stability.

[0068] III. System Operation Process and Performance Verification

[0069] The complete working process of the system in this embodiment under the conditions of a hydrothermal vent at a depth of 2000m and a temperature of 300℃ is as follows:

[0070] The deep-sea hydrothermal fluid (300℃) flows through the guide holes of the primary heat pipe protective cover 6 and undergoes forced convection heat exchange with the 24 longitudinal fins of the evaporation section 15 of the primary heat pipe 12. Heat is conducted through the fins and pipe wall to the inner wall of the heat pipe, heating the high-purity degassed water working fluid. The working fluid boils and vaporizes at approximately 260–290℃. The water vapor carries the latent heat of vaporization and rises along the pipe cavity, passing through the transition section 14 to the condensation section 13. The steam condenses and releases heat on the inner wall of the condensation section 13. The released latent heat is conducted through a 1.5mm wall thickness to the outer wall of the pipe and then transferred to the copper square column 11 through the indium foil layer. Actual measurements show that the total temperature drop from the steam to the outer wall of the copper square column in this process is approximately 4.5℃. When the steam temperature is approximately 280℃, the temperature of the outer wall of the copper square column is approximately 226.5℃.

[0071] The copper square pillar 11 distributes heat evenly to its four sides through internal heat conduction, ensuring uniform temperature distribution on each side. Thermal paste further transfers heat to the hot-side surfaces of the 120 thermoelectric generators 10. Waste heat from the cold-side surfaces of the thermoelectric generators 10 is dissipated to the copper cold plate 9 via thermal paste. The actual operating temperature difference of each thermoelectric generator 10 is approximately 205.2℃, which is within the device's optimal operating temperature range.

[0072] Driven by a temperature difference of 205.2℃, 120 thermoelectric generators 10 generate a thermoelectric electromotive force based on the Seebeck effect, and the system output can stably provide ≥1000W of net power.

[0073] Meanwhile, mechanical simulations have verified that under the combined effects of external hydrostatic pressure and internal high-temperature steam pressure, the maximum equivalent stress on the wall of the TA2 titanium alloy primary heat pipe 12 is approximately 34.09 MPa, with a safety factor of approximately 7.04. The system can operate continuously and stably under these conditions, with a design life of ≥10 years.

[0074] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A static thermoelectric power supply system based on deep-sea hydrothermal vents, characterized in that, Deployed in the deep-sea hydrothermal vent area, it includes a primary heat pipe heat absorption and transmission module (7), a thermoelectric power generation core module (5), a secondary cascaded heat pipe heat dissipation module (1), a pressure protection module (4), and a power management module (3); the primary heat pipe heat absorption and transmission module (7) adopts a pressure-resistant and corrosion-resistant gravity heat pipe to collect the thermal energy of the deep-sea hydrothermal vent and transmit it to the thermoelectric power generation core module (5); the thermoelectric power generation core module (5) includes an array composed of multiple thermoelectric power generation plates (10), which convert thermal energy into electrical energy based on the Seebeck effect; The secondary cascaded heat pipe heat dissipation module (1) consists of a heat-conducting cold plate and a pressure-resistant and corrosion-resistant secondary heat pipe (8), which is used to discharge the waste heat of the cold end of the thermoelectric generator (10) into the deep seawater; the pressure protection module (4) is made of a pressure-resistant and corrosion-resistant material and a sealed shell is used to enclose the thermoelectric generator core module (5) and the power management module (3) inside the sealed shell to isolate the seawater from the high-pressure environment; the power management module (3) adopts a DC-DC conversion and energy storage unit to realize the stable storage and output of electrical energy.

2. The static thermoelectric power supply system based on deep-sea hydrothermal vents according to claim 1, characterized in that, The gravity heat pipe of the primary heat pipe heat transfer module (7) is a primary heat pipe (12). The primary heat pipe (12) is divided into an evaporation section (15), a transition section (14) and a condensation section (13) along its length. The evaporation section (15) is made of longitudinal fins formed by integrated hot extrusion to expand the heat collection area. The condensation section (13) is machined to remove fins and reduce the wall thickness. The transition section (14) is made by slope processing to achieve a smooth transition of wall thickness and is covered with heat insulation material. The primary heat pipe (12) is filled with high-purity degassed water as a phase change heat transfer medium.

3. The static thermoelectric power supply system based on deep-sea hydrothermal vents according to claim 1, characterized in that, The thermoelectric power generation core module (5) also includes a heat-conducting column. The heat-conducting column is made of a high thermal conductivity metal material and is used to evenly distribute the heat energy transmitted by the primary heat pipe (12) to the hot end of each thermoelectric power generation piece (10). The heat-conducting column has an installation through hole. The condensation section (13) of the primary heat pipe (12) passes through the installation through hole. The condensation section (13) and the installation through hole are connected by an interference fit through a hydraulic expansion process to maintain residual contact pressure at the interface to compensate for the thermal expansion difference of dissimilar materials under high temperature conditions.

4. The static thermoelectric power supply system based on deep-sea hydrothermal vents according to claim 3, characterized in that, An indium foil is provided between the outer wall of the condensation section (13) and the inner wall of the mounting through hole to fill the micro gaps at the interface and reduce the contact thermal resistance; thermal grease is applied between the hot end face of the thermoelectric generator (10) and the thermally conductive square column, and between the cold end face of the thermoelectric generator (10) and the thermally conductive cold plate.

5. The static thermoelectric power supply system based on deep-sea hydrothermal vents according to claim 1, characterized in that, The heat-conducting cold plate of the secondary cascaded heat pipe heat dissipation module (1) is a copper cold plate (9). The copper cold plate (9) is attached to the cold end face of the thermoelectric generator (10) to collect waste heat and achieve uniform temperature at the cold end. The secondary heat pipe (8) is a gravity heat pipe with a sintered core (17) inside and filled with high-purity ammonia as the heat transfer medium. One end of the secondary heat pipe (8) is thermally connected to the copper cold plate (9), and the other end extends into the deep seawater to discharge waste heat into the seawater.

6. The static thermoelectric power supply system based on deep-sea hydrothermal vents according to claim 1, characterized in that, The wall material of the primary heat pipe (12) and the secondary heat pipe (8) and the sealing shell material of the pressure protection module (4) are selected from one or more of TA2 pure titanium, TC4 titanium alloy, Gr7 titanium alloy or nickel-based alloy; the sealing shell adopts a composite sealing structure combining atmospheric pressure sealing and potting seal.

7. The static thermoelectric power supply system based on deep-sea hydrothermal vents according to claim 1, characterized in that, It also includes a heat pipe protection and flow guiding module, which includes a primary heat pipe protection shield (6) and a secondary heat pipe hyperbolic flow guiding shield (2). The primary heat pipe protection shield (6) covers the outside of the evaporation section (15) of the primary heat pipe heat absorption and transmission module (7) and is made of pressure-resistant and corrosion-resistant alloy to resist the impact of deep-sea hot spring jets and sand and gravel abrasion. The secondary heat pipe hyperbolic flow guiding shield (2) is set outside the heat dissipation section of the secondary heat pipe (8) and its flow channel surface is hyperbolic to optimize seawater convection heat transfer, improve heat dissipation efficiency and reduce fluid resistance.

8. The static thermoelectric power supply system based on deep-sea hydrothermal vents according to claim 1, characterized in that, The thermoelectric generator (10) is a medium-high temperature thermoelectric generator with solder replacement, electrode anti-oxidation coating and encapsulation structure reinforcement, to adapt to the high temperature and high pressure working conditions of deep-sea hydrothermal springs; the array of the thermoelectric generator (10) consists of multiple thermoelectric generators (10) evenly arranged around the heat-conducting square column and electrically connected by series and / or parallel combination.

9. The static thermoelectric power supply system based on deep-sea hydrothermal vents according to claim 1, characterized in that, The system has a modular expansion structure. Each system is a unit module. Each unit module is equipped with a mechanical installation interface and an electrical parallel connection interface that can be expanded and linked. Multiple unit modules can be combined and connected in parallel through the mechanical installation interface and the electrical parallel connection interface to achieve on-demand multiplication of the total output power.

10. The static thermoelectric power supply system based on deep-sea hydrothermal vents according to claim 1, characterized in that, The system is designed with a net output power of ≥1000W, the temperature difference between the hot and cold ends of the thermoelectric generator (10) is ≥200℃, and the structural safety factor of the primary heat pipe (12) and the secondary heat pipe (8) is ≥7.

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