Buried thermoelectric cell

Abstract

The application belongs to the technical field of thermoelectric batteries, and discloses a buried thermoelectric battery, which utilizes the temperature difference between the ground surface waste heat and the underground soil to generate electricity, and simultaneously solves the problems of large cold end contact thermal resistance and easy pollution. The battery comprises a heat collecting module, a heat conducting module, a protective thermal insulation layer, a heat dissipating module and a thermoelectric conversion module. The heat collecting module is arranged above the ground surface to collect the ground surface waste heat. One end of the heat conducting module is connected with the heat collecting module, and the other end extends below the ground surface to conduct heat from the ground surface to the underground soil. The protective thermal insulation layer is wrapped outside the heat conducting module below the ground surface. The thermoelectric conversion module is arranged around the end of the heat conducting module extending to the underground soil. The thermoelectric conversion module has group A thermoelectric devices and group B thermoelectric devices, which are respectively adapted to different temperature difference directions to output electric energy. The heat dissipating module is sleeved outside the thermoelectric conversion module. The application meets the long-term, stable and maintenance-free self-power supply demand of underground equipment, and has the advantages of simple structure, convenient installation and low cost.

Description

Technical Field

[0001] This application belongs to the field of thermoelectric battery technology, and particularly relates to a buried thermoelectric battery. Background Technology

[0002] In scenarios such as underground pipe networks, mines, and geological monitoring, various sensing and monitoring devices need continuous power supply. However, traditional power grid wiring is costly and difficult to cover remote areas, and battery replacement and maintenance are difficult. At the same time, there is a natural stable temperature in the shallow underground, and the unutilized thermal energy resources such as the ground ambient temperature and the residual heat of buried pipelines can form a temperature difference with it to generate electricity.

[0003] Oak Ridge National Laboratory in the United States developed a dual-purpose underground thermal battery (US62819755P0), which uses underground double-layer storage tanks combined with phase change materials to achieve thermal energy storage and grid peak shaving. However, this device mainly focuses on thermal energy storage, resulting in low power generation efficiency. It also has a complex structure and a large footprint, making it unsuitable for self-powered small underground equipment. Traditional earth batteries (US4457988A) generate electricity through the electrochemical reaction between underground electrodes and electrolytes, but they suffer from problems such as easy electrode corrosion, low output power, and short lifespan.

[0004] Domestically, there are already patents related to geothermal thermoelectric integrated systems (CN116526892A), in-situ geothermal thermoelectric power generation devices, and buried pipeline waste heat temperature difference power generation devices, realizing the basic utilization of underground temperature differences. However, in-situ geothermal power generation utilizes shallow geothermal energy at depths of 1000m to 3000m, and buried pipes utilize waste heat from the pipelines; neither considers using surface waste heat as a heat source. Furthermore, the US focuses on large-scale thermal energy storage and grid coordination, while China focuses on the structural design of small power generation devices. Neither has solved problems such as efficient heat dissipation at the underground cold end, corrosion and compression resistance of the device, and no medium leakage. There is an urgent need for a compact, environmentally adaptable buried thermoelectric battery. Summary of the Invention

[0005] The purpose of this application is to provide a buried thermoelectric battery that generates electricity by utilizing the temperature difference between surface waste heat and underground soil, while solving the problems of high thermal resistance at the cold end and easy pollution.

[0006] To achieve the above objectives, this application provides the following technical solution: A buried thermoelectric battery includes a heat collection module, a heat conduction module, a protective heat insulation layer, a heat dissipation module, and a thermoelectric conversion module; The heat collection module is installed above the ground surface and has a heat collection module core inside. The lower end of the heat collection module core is directly connected to the upper end of the heat conduction module core through internal threads to form a continuous solid heat conduction path. The heat-conducting module extends from the ground surface to the underground, and the underground portion of it is wrapped with the protective heat insulation layer. The protective heat insulation layer includes a protective heat insulation material directly wrapped around the outer layer of the heat-conducting module and a metal protective layer disposed on the outside of the protective heat insulation material. The end structure of the heat-conducting module extending underground changes from a cylindrical shape to a rounded square shape, and the thermoelectric conversion module is attached to the four sides of the rounded square shape. The thermoelectric conversion module includes a group of thermoelectric devices A and a group of thermoelectric devices B. The hot surface of the group of thermoelectric devices A is attached to the side of the heat-conducting module, and the hot surface of the group of thermoelectric devices B faces outward. The heat-relieving module is sleeved on the outside of the thermoelectric conversion module. The heat-relieving module has an inner cavity that fits the rounded square shape. The inner wall of the inner cavity is in contact with the cold surface of the B group of thermoelectric devices. The outer side of the heat-relieving module extends with heat-relieving fins for direct contact with the soil. The thermoelectric devices in group A and group B are connected in parallel to the power management module to meet the power generation needs of different temperature differences on the surface and underground.

[0007] In some embodiments, the outer side of the inner core of the heat-conducting module is wrapped with heat-insulating material, and a metal protective layer is provided on the outer layer of the heat-insulating material. A battery interface and a backup battery interface are fixed on the metal protective layer, and the thermoelectric conversion output wire is transmitted to the battery interface through the internal channel of the heat-insulating material.

[0008] In some embodiments, the surface of the metal protective layer of the protective heat insulation layer is coated with an anti-corrosion material, and the metal protective layer and the outer metal protective layer of the heat conduction module are connected by a variable diameter sleeve, with the connection point located above the ground.

[0009] In some embodiments, in the thermoelectric conversion module, thermoelectric devices on adjacent sides are connected in parallel to form group A and group B thermoelectric devices; in the height direction, thermoelectric devices on the same side of each group are connected in series, and the outputs of group A and group B thermoelectric devices are both connected to the power management module.

[0010] In some embodiments, a positioning block is provided on the inner wall of the heat-relieving module for assembling and positioning the thermoelectric conversion module; a shaped heat insulation strip is arranged at the corner of the heat-relieving module, the heat insulation strip being located between the rounded corner of the heat-conducting module and the heat-relieving module, for blocking the heat bypass from the inner core of the heat-conducting module to the heat-relieving module.

[0011] In some embodiments, thermally conductive material is filled between the thermoelectric device and the heat-conducting module, and between the thermoelectric device and the heat-reducing module. The thermally conductive material is one or more of high thermal conductivity grease, graphene, or carbon paper.

[0012] In some embodiments, the heat-relieving module includes an integrally formed inner cavity and outwardly extending heat-relieving fins, the heat-relieving fins being arranged in a circular matrix around the battery, and the entire surface of the heat-relieving module being coated with a graphene anti-corrosion coating.

[0013] In some embodiments, the power management module is arranged in the gap of the thermoelectric conversion module or in the protective insulation layer; the power management module includes a comparison circuit, a voltage regulator circuit, a bidirectional control circuit, and an energy storage battery; the comparison circuit is used to compare the output voltage of the A group of thermoelectric devices and the B group of thermoelectric devices and select the larger one to input to the voltage regulator circuit; the voltage regulator circuit is used to convert the input fluctuating voltage into a constant voltage output; the bidirectional control circuit is connected to the energy storage battery and is used to provide auxiliary power to the load when the load output is unstable.

[0014] In some embodiments, the voltage regulator circuit is a Buck-Boost circuit with an input voltage range of 3V to 30V; the energy storage battery is arranged inside the protective insulation layer or directly underground via an internal interface connection, or arranged on the ground surface and connected via an external interface.

[0015] In some embodiments, the buried thermoelectric battery further includes modified backfill soil, which is filled around the heat-dissipating fins of the heat-dissipating module and compacted. The backfill soil is doped with high thermal conductivity powder, which includes one or more of graphite, aluminum powder or silicon carbide, to improve the heat transfer efficiency between the heat-dissipating module and the soil.

[0016] Compared with the prior art, the buried thermoelectric battery provided in this application has the following advantages: This application meets the long-term, stable, and maintenance-free self-power supply requirements of underground equipment, and has a simple structure, convenient installation, and low cost.

[0017] This application can directly utilize the waste heat of the earth's surface and the temperature difference between the shallow underground layer to generate electricity. The battery adopts a fully solid-state connection, which conducts the surface heat energy to the shallow underground thermoelectric conversion module, and dissipates the heat to the shallow underground layer through the metal heat dissipation module. The whole process is passive and has no risk of medium leakage.

[0018] This application designs a dual-group device arrangement in reverse, enabling it to adapt to temperature variations across different seasons or times. It utilizes thermal expansion and contraction to achieve the overall assembly of the battery's core functions, and employs internal thread connections to improve the ease of connecting segmented sections of long heat-conducting pillars. Through protective insulation design and backfill soil modification, it effectively enhances the cold-end thermal resistance, thereby improving the thermoelectric battery's output performance. This invention provides a long-duration, low-power battery solution for western regions, deserts, and border areas.

[0019] Furthermore, this application employs a solid-state connection design, which can directly conduct surface waste heat to the shallow underground layer to generate electricity. This battery eliminates the need for a circulating cooling circuit, avoiding media leakage issues. Surface coatings and backfill soil modification enhance heat dissipation efficiency and reduce corrosion damage. Calculations show that when the heat collection temperature reaches 60°C, the battery conversion efficiency is nearly 2%, with a typical example generating up to 10W of power. This pure solid-state buried thermoelectric battery can be applied in sparsely populated or uninhabited areas such as western regions, deserts, and border areas. Attached Figure Description

[0020] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the technical description will be briefly introduced below.

[0021] Figure 1 A schematic diagram of the overall structure of the buried thermoelectric battery provided in this application; Figure 2 This is a top view of the buried thermoelectric battery provided in this application. Figure 3 A top view schematic diagram of the heat collection module-heat conduction module-protective insulation layer provided in this application; Figure 4 This is a top view of the thermally conductive module-thermoelectric device provided in this application. Figure 5 A side view of the thermoelectric conversion module-heat dissipation module provided in this application; Figure 6 A top view of the heat dissipation module provided in this application; Figure 7 This is a schematic diagram of the functional structure of the power management module provided in this application.

[0022] Explanation of reference numerals in the attached figures: 1. Heat collection module; 2. Heat conduction module; 3. Protective insulation layer; 4. Heat dissipation module; 5. Thermoelectric conversion module; 6. Backfill soil; 2-1. Battery interface; 2-2. Backup battery interface; 2-3. Thermally conductive and insulating material; 3-1. Protective and heat-insulating materials; 3-2. Metal protective layer; 4-1. Heat-dissipating fins; 4-2. Heat insulation strip; 4-3. Inner cavity; 4-4. Positioning block; 5-1. Thermoelectric devices; 5-2. Thermally conductive materials; 5-3. Group A thermoelectric devices; 5-4. Group B thermoelectric devices. Detailed Implementation

[0023] The following detailed description provides further details on specific implementation methods.

[0024] like Figures 1 to 7As shown, this application provides a buried thermoelectric battery with an all-solid-state connection structure. Buried in the underground surface layer (Quaternary loose layer), it can generate electricity. The battery uses surface waste heat as a heat source and underground soil as a cold source to achieve temperature difference power generation. The battery includes a heat collection module 1, a heat conduction module 2, a protective insulation layer 3, a heat dissipation module 4, a thermoelectric conversion module 5, and an energy management module.

[0025] The heat collection module 1 is used to collect waste heat from the ground surface. It is arranged above the ground surface and is mainly composed of columnar materials with good thermal conductivity. Its surface is coated with a heat collection coating, which can be adapted to both lit and non-lit environments.

[0026] The heat collection module 1 is directly connected to the heat conduction module 2. The heat conduction module 2 is partially set above the ground. Its core is made of the same material as the heat conduction column of the heat collection module 1. Its surface is coated with a heat insulation coating and wrapped with a lightweight heat insulation material to avoid heat loss during the heat conduction process.

[0027] The heat-conducting module 2 extends from the ground to the underground and is equipped with a protective heat insulation layer 3. The protective heat insulation layer 3 is mainly composed of rubber and plastic foam insulation material, covered with metal structural components, and the surface of the structural components is coated with anti-corrosion material.

[0028] The lower part of the protective insulation layer 3 is connected to the thermoelectric conversion module 5. The thermoelectric conversion module 5 takes the heat collection module 1 as the heat source center and arranges thermoelectric devices 5-1 around it. The thermoelectric devices 5-1 are divided into two groups: group A thermoelectric devices 5-3 and group B thermoelectric devices 5-4, which are used for output in different environments. For example, in summer, when the surface temperature is higher than the soil temperature, the output is provided by group A thermoelectric devices 5-3, while in winter, when the surface temperature is lower than the soil temperature, the output is provided by group B thermoelectric devices 5-4.

[0029] The inner side of the thermoelectric conversion module 5 consists of heat-conducting columns extending from the heat collection module 1 and the heat-conducting module 2, while the outer side is the heat-dissipating module 4. The heat-dissipating module 4 uses a finned structure of a certain area to dissipate the residual heat from the ground surface that has not been converted into electrical energy into the soil. The heat-dissipating module 4 is in direct contact with the soil. The backfill soil 6 is mixed with highly thermally conductive powders (such as graphite, aluminum powder, silicon carbide, etc.) and compacted to improve the heat dissipation efficiency.

[0030] The power management module is located in the gap of the thermoelectric conversion module 5. It mainly consists of DC voltage regulation, circuit switching, and battery functions. Its power transmission line is arranged in the heat insulation module, and the outside is a waterproof aviation plug interface.

[0031] Specifically, such as Figure 1 As shown, the heat collection module 1 is located on top of the battery, above the ground, and its surface is coated with heat collection material. In environments with sufficient sunlight, a ceramic-based composite coating or anodizing and blackening treatment can be used. The heat collection module 1 has a heat collection module core, which is a highly thermally conductive column used to transfer heat to the heat conduction module 2.

[0032] When the heat-conducting module 2 is underground, a protective heat insulation layer 3 is installed externally to prevent underground corrosion. The heat-conducting module 2 continuously transfers heat to the thermoelectric conversion module 5. Part of the heat energy is converted into electrical energy by thermoelectricity and then forms a stable DC output through the power management module. Optionally, the DC power supply output voltage is 12V. The heat energy that is not converted into electrical energy is transferred to the backfill soil 6 through the heat-dissipating module 4. To enhance the heat transfer efficiency between the heat-dissipating module 4 and the soil and reduce the cold-end thermal resistance, the backfill soil 6 needs to be modified by adding high thermal conductivity powders (such as graphite, aluminum powder, silicon carbide, etc.) and compacting it. Figure 2 As shown.

[0033] Preferably, the core of the heat collection module is made of a material with good thermal conductivity, such as aluminum, copper or other metal materials, and its surface is coated with heat collection material. In a well-lit environment, for example, a ceramic-based composite coating or an oxidation blackening treatment is used. In a non-lit environment, for example, a metal-ceramic composite coating or a graphene coating is used.

[0034] like Figure 3 As shown, the heat-conducting module 2 has a heat-conducting module core, which is made of the same material as the heat-collecting module core. The two are connected by internal threads, and the thread surface is coated with high thermal conductivity grease. The outer side of the core is wrapped with heat-insulating material 2-3, and the outer layer of the heat-insulating material is a metal protective layer. The thermoelectric conversion output wires are output to battery interface 2-1 and backup battery interface 2-2 via the heat-insulating material 2-3. When the heat-conducting module 2 is underground, a protective heat-insulating layer 3 is laid on its outer layer. The protective heat-insulating material 3-1 of the protective heat-insulating layer 3 is directly wrapped around the outer layer of the heat-conducting module 2. The outer layer of the protective heat-insulating material 3-1 is also provided with a metal protective layer 3-2. The metal protective layer 3-2 and the metal protective layer of the heat-conducting column are connected by a variable diameter sleeve. The connection part is located above the ground for easy maintenance.

[0035] Preferably, due to the long transmission distance and considering ease of installation, the core of the heat conduction module is connected in multiple segments, each segment using an internal thread connection. To improve battery reliability, welding or other methods can be used to connect the core of the heat conduction module.

[0036] Preferably, the inner core of the heat-conducting module changes from a cylinder to a rounded square structure at the thermoelectric conversion module 5, which facilitates the installation of the thermoelectric device 5-1. The outer side of its rounded corners is attached to the heat insulation strip 4-2 of the heat-relieving module 4. The heat insulation strip 4-2 is a shaped heat insulation strip.

[0037] Preferably, a heat insulation layer is arranged on the outer side of the inner core of the heat-conducting module. The heat insulation material can be a lightweight heat insulation material such as silicate board or aerogel. The heat insulation material has an electrical wire transmission channel inside, and a metal protective layer is arranged on the outer layer of the heat insulation material. A battery connection interface is fixed on the protective layer.

[0038] like Figure 3As shown, the protective heat insulation layer 3 is composed of heat insulation material and metal protective layer. The heat insulation material can be a low thermal conductivity material with good elasticity and closed-cell rate, such as rubber and plastic foam insulation material, rigid polyurethane foam, and polyolefin foam. The surface of the outer metal protective layer is coated with anti-corrosion material. The metal protective layer and the protective layer of the heat conduction module 2 are connected by a variable diameter sleeve. The connection can be made by thread, ferrule, spot welding or full welding. The connection part is located above the ground for easy maintenance.

[0039] like Figure 4 As shown, to accommodate the arrangement of thermoelectric devices, when the heat transfer module core is transferred to the thermoelectric conversion module 5, its structure changes from a cylinder to a rounded square structure. Thermoelectric devices 5-1 are arranged around the rounded square structure, with two sides connected in parallel as group A thermoelectric devices 5-3, used for scenarios where the surface temperature is higher than the underground temperature, and the other two sides connected in parallel as group B thermoelectric devices 5-4, used for scenarios where the surface temperature is lower than the underground temperature.

[0040] The thermoelectric conversion module 5 consists of four groups of thermoelectric devices arranged around the rounded corners of the heat-conducting pillar. Adjacent devices are connected in parallel to form two groups: group A (thermoelectric device 5-3) and group B (thermoelectric device 5-4). The hot surface of group A (thermoelectric device 5-3) is attached to the inner core of the heat-conducting module, while the hot surface of group B (thermoelectric device 5-4) is attached to the inner wall of the heat-dissipating module 4. The number of devices along the height direction in both groups A (thermoelectric device 5-3) and B (thermoelectric device 5-4) can be increased according to the design power. Devices on the same side of each group are connected in series along the height direction, while devices on different sides of each group are connected in parallel. Both groups A and B output to the power management module.

[0041] Preferably, the contact surfaces of the thermoelectric devices are all covered with a highly thermally conductive material to reduce contact thermal resistance; thermally conductive grease or gel can be used conventionally.

[0042] Preferably, the heat-conducting module extends from the ground surface to the underground. Due to the requirement for burial depth, the inner core of the heat-conducting module is installed through an internal thread connection to enhance the convenience of transportation and construction.

[0043] like Figure 5 As shown, in the height direction, multiple thermoelectric devices 5-1 can be connected in series according to the power design. In the current example scenario, 10 thermoelectric devices 5-1 are connected in series in the height direction, that is, the power output of each group is 20 thermoelectric devices. The output wires are directly connected to the wires reserved in the heat insulation material through the top device and transmitted to the battery interface. The thermoelectric devices 5-1, heat conduction module 2, and heat dissipation module 4 are all equipped with heat conduction material 5-2 to reduce contact thermal resistance. The heat conduction material 5-2 is, for example, a high thermal conductivity grease material.

[0044] like Figure 6As shown, the heat-dissipating module 4 includes heat-dissipating fins 4-1, heat insulation strips 4-2, an inner cavity 4-3, and positioning blocks 4-4. Its material is the same as the core of the heat-conducting module, for example, it can be manufactured using a one-piece molding process. All surfaces are coated with a graphene anti-corrosion coating. The inner cavity 4-3 of the heat-dissipating module 4 is adapted to the thermoelectric conversion module 5. To ensure assembly, positioning blocks 4-4 are provided on the inner cavity 4-3. Heat insulation strips 4-2 are arranged at the corners of the device. To enhance its connection with the soil foundation, the heat-dissipating module 4 is designed with multiple fin structures, namely the heat-dissipating fins 4-1. The entire surface of the heat-dissipating module 4 requires anti-corrosion treatment. The inner cavity 4-3 is the assembly cavity for heat conduction and thermoelectric conversion; it is a rounded-corner chamber.

[0045] Preferably, the heat-dissipating fins 4-1 are arranged in a circular matrix around the battery, and their overall heat dissipation area can match the power requirement design. The fins are in direct contact with the soil, and their surface is coated with a graphene anti-corrosion coating. To reduce the thermal resistance in contact with the soil, the backfill soil 6 around the heat-dissipating fins 4-1 needs to be modified and compacted. The modification can be achieved by doping with high thermal conductivity powders (such as graphite, aluminum powder, silicon carbide, etc.).

[0046] The inner side of the inner cavity 4-3 is attached to the thermoelectric device 5-1, forming a rounded square structure. The outer side is integrally formed with the heat-dissipating fins, resulting in an overall structure of an outer circle and an inner square. Two positioning blocks 4-4 are arranged on each side of the inner side of the rounded cavity for use in assembling the thermoelectric conversion module.

[0047] Preferably, the heat insulation strip 4-2 is rounded and can be made of low thermal conductivity materials such as aerogel to prevent heat from the inner core of the heat-conducting module from being transferred outward from the rounded corners, thus forming a thermal bypass.

[0048] The assembly method of the heat dissipation module 4, the thermoelectric conversion module 5, and the inner core of the heat conduction module is as follows: Thermoelectric device 5-1 is first fixed to the inner core of the heat conduction module with high thermal conductivity grease. The other side of thermoelectric device 5-1 is coated with a high thermal conductivity material with a certain elasticity, such as graphene or carbon paper. A thin layer of silicone grease is coated between the high thermal conductivity material and the device. The heat dissipation module 4 is heated to cause it to expand. The inner core of the heat conduction module, on which the thermoelectric device 5-1 is attached, is then inserted into the heat dissipation module 4. The heat dissipation module 4 is cooled to shrink and adhere to the insulating layer of the thermoelectric device 5-1, thereby realizing the assembly of the heat dissipation module 4 with the thermoelectric conversion module 5 and the inner core of the bottom heat conduction module.

[0049] like Figure 7 As shown, the electrical energy output from thermoelectric device 5-3 in group A and thermoelectric device 5-4 in group B is respectively connected to the power management module. The power management module consists of a comparator circuit, a voltage regulator circuit, a bidirectional control circuit, an energy storage battery, and a battery interface. Figure 7 The right side shows the aviation plug, the spare aviation plug, and the energy storage battery.

[0050] The comparator circuit compares the outputs of groups A and B, and the larger output is sent to the voltage regulator circuit. The voltage regulator circuit is primarily a Buck-Boost circuit, capable of handling a wide range of input voltages. In this example, the input voltage range is 3~30V. The output power is converted into a constant voltage source by the voltage regulator circuit and then output to battery interface 2-1 and backup battery interface 2-2 via a bidirectional control circuit. The bidirectional control circuit monitors the load output and promptly provides stable power to the load through the energy storage battery.

[0051] The energy storage battery is connected to the bidirectional control circuit. When the load output is detected to be unstable, it provides auxiliary power to the load in a timely manner. The energy storage battery can be placed on the surface or underground. When the energy storage battery is placed on the surface, it is convenient for maintenance and replacement. The energy storage battery interface needs to be moved to the vicinity of battery interface 2-1. When the energy storage battery is placed underground, it can improve the battery's load-bearing stability. The energy storage battery is connected through internal interface wiring and is directly placed in the heat insulation protection layer 3.

[0052] Preferably, the main body of the voltage regulator circuit is a Buck-Boost circuit. To adapt to a wide range of input voltages, it can be composed of one or more stages of circuits. Its design goals are low voltage start-up, wide range adaptation, and stable voltage output.

[0053] Preferably, the buried thermoelectric battery adopts an all-solid metal heat conduction method to avoid the risk of medium leakage. Since the outer side of the heat-conducting inner core is still protected by two layers, the cylindrical heat-conducting inner core can also be replaced with a fluid inner core according to the actual needs of the scenario.

[0054] Optionally, buried thermoelectric batteries can be used individually or in multiple parallel or series connections depending on power requirements.

[0055] The above description is only a specific embodiment of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application.

Claims

1. A buried thermoelectric battery, characterized in that, include: The heat collection module (1) is arranged above the ground surface to collect waste heat from the ground surface; The heat-conducting module (2) is connected at one end to the heat-collecting module (1) and extends to the ground surface at the other end to conduct heat from the ground surface to the ground. A protective heat insulation layer (3) is wrapped around the outside of the heat-conducting module (2) located below the ground surface; A thermoelectric conversion module (5) is disposed around the end of the heat-conducting module (2) extending underground, and its hot end is in contact with the heat-conducting module (2); the thermoelectric conversion module (5) has a group A thermoelectric device (5-3) and a group B thermoelectric device (5-4) arranged around the end of the heat-conducting module (2), and the group A thermoelectric device (5-3) and the group B thermoelectric device (5-4) are adapted to different temperature difference directions to output electrical energy; The heat dissipation module (4) is fitted on the outside of the thermoelectric conversion module (5) and is in direct contact with the underground soil, used to dissipate the unconverted heat into the soil.

2. The buried thermoelectric battery according to claim 1, characterized in that, The heat-conducting module (2) has a heat-conducting module core, the heat-conducting module core is made of the same material as the heat-collecting module core of the heat-collecting module (1), and the two are connected by internal threads; the outer side of the heat-conducting module core is wrapped with heat-insulating material (2-3), and the outer layer of the heat-insulating material (2-3) is provided with a metal protective layer.

3. The buried thermoelectric battery according to claim 2, characterized in that, The inner core of the heat-conducting module has a rounded square structure at the position corresponding to the thermoelectric conversion module (5). The thermoelectric devices A (5-3) and B (5-4) are attached to the four sides of the rounded square.

4. The buried thermoelectric battery according to claim 1 or 3, characterized in that, In the thermoelectric conversion module (5), the thermoelectric devices on adjacent sides are connected in parallel to form the A group of thermoelectric devices (5-3) and the B group of thermoelectric devices (5-4); in the height direction, the thermoelectric devices on the same side of each group are connected in series, and the outputs of the A group of thermoelectric devices (5-3) and the B group of thermoelectric devices (5-4) are both connected to the power management module.

5. The buried thermoelectric battery according to claim 4, characterized in that, The hot surface of the thermoelectric device A (5-3) is attached to the side of the inner core of the heat-conducting module and is used to work when the surface temperature is higher than the underground soil temperature. The hot surface of the thermoelectric device B (5-4) is attached to the inner wall of the heat-relieving module (4) and is used to work when the surface temperature is lower than the underground soil temperature.

6. The buried thermoelectric battery according to claim 1, characterized in that, The protective heat insulation layer (3) includes a protective heat insulation material (3-1) and a metal protective layer (3-2). The protective heat insulation material (3-1) is directly wrapped around the outer layer of the heat-conducting module (2), and the metal protective layer (3-2) is located on the outside of the protective heat insulation material (3-1).

7. The heat-dissipating module (4) includes an integrally formed inner cavity (4-3) and outwardly extending heat-dissipating fins (4-1). The inner cavity (4-3) has a rounded square structure to fit the thermoelectric conversion module (5). A positioning block (4-4) is provided on the inner side wall of the inner cavity (4-3). The heat-dissipating fins (4-1) are arranged in a circular matrix around the battery and are in direct contact with the soil.

8. The inner cavity (4-3) of the heat-relieving module (4) is filled with thermally conductive material (5-2) between the end of the heat-conducting module (2) and the thermoelectric conversion module (5), and between the thermoelectric conversion module (5) and the heat-relieving module (4); heat insulation strips (4-2) are arranged at the corners of the heat-relieving module (4) to block the heat bypass from the inner core of the heat-conducting module to the heat-relieving module (4).

9. The buried thermoelectric battery according to claim 1, characterized in that, It also includes an energy management module, which is arranged in the gap of the thermoelectric conversion module (5) or in the protective heat insulation layer (3). The energy management module has a comparison circuit, a voltage regulator circuit, a bidirectional control circuit and an energy storage battery. The comparison circuit is used to compare the output voltage of the thermoelectric device A (5-3) and the thermoelectric device B (5-4) and select the larger one to input to the voltage regulator circuit.

10. The buried thermoelectric battery according to claim 1, characterized in that, The backfill soil (6) at the location where the buried thermoelectric battery is installed is modified. The backfill soil (6) is mixed with high thermal conductivity powder and compacted. The high thermal conductivity powder includes one or more of graphite, aluminum powder or silicon carbide, in order to improve the heat transfer efficiency between the heat dissipation module (4) and the soil.

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