Self-Powered Device Based on Thermal Diode and Internet of Things Distributed Sensor Node

Abstract

The present invention discloses a self-powered device and an Internet of Things distributed sensor node based on a thermal diode. The self-powered device includes a forward / reverse thermal diode, electrodes and N-type / P-type thermoelectric bars, a boosting device and an energy storage device. The forward / reverse thermal diodes have the same structure, and are both composed of a low-thermal-conductivity mold prefabricated with a groove structure and a boss and a high-thermal-conductivity filler; the array form and number of the thermal diodes, the different grooves prefabricated in the low-thermal-conductivity mold, and the different high-thermal-conductivity fillers filled therein all directly affect the service performance of the self-powered device. In the present invention, even the long-term non-high-temperature waste heat generated in a restricted scenario or the short-term high-temperature waste heat generated in a remote scenario can enable the self-powered device with a millimeter-level external dimension to continuously output a voltage of volts or more for dozens of minutes. The integration of the structural unit is higher, the scalability in a restricted scenario is stronger, and the durability and reliability in a remote scenario are higher, providing a new idea for the self-power supply of Internet of Things sensor nodes in complex environments.

Description

Technical Field

[0001] The present invention belongs to the technical field of Internet of Things energy and power, and particularly relates to a self-powered device based on a thermal diode and an Internet of Things distributed sensor node. Background Art

[0002] With the increasing depletion of non-renewable energy sources such as fossil fuels and the increasingly severe environmental pollution situation, it is an urgent problem to achieve efficient utilization of energy and develop clean and green new energy sources. New energy power technologies, such as photovoltaic power generation, wind power generation, and thermoelectric power generation, can convert the energy that cannot be utilized in the environment into available electric energy, without consuming fuel and without facing the problem of dealing with waste batteries, providing a feasible path for solving the above problems. In recent years, with the development of 5G communication technology and intelligent sensors, the Internet of Things technology has served industries such as intelligent security, intelligent transportation, smart home, and intelligent logistics, and humanity has entered the intelligent era of "everything connected". As the basic component module of the Internet of Things wireless communication technology, sensor nodes require energy to operate. For Internet of Things sensor nodes deployed in complex environments such as restricted scenarios (such as narrow spaces) or remote scenarios (such as forests), it is less feasible and inconvenient to operate by relying on traditional energy supplies such as wired power sources or wireless batteries. Moreover, once battery power supply is enabled, due to the limited storage capacity, the lifespan is limited and needs to be replaced regularly, increasing the cost and difficulty of manual maintenance; by relying on new energy power technologies such as photovoltaic power generation or wind power generation, the floor area is large, and the production cost of photovoltaic power generation raw materials is high, and the production process is accompanied by toxic and harmful chemical substances. In addition, the rotating components in wind power generation also face mechanical wear problems

[0003] For existing thermoelectric power generation devices, most of the service voltages are in the millivolt (mV) level, and the power is in the sub-milliwatt (0.1 mW) and micro-watt (μW) levels, making it difficult to meet the actual power supply requirements of the nodes. In order to increase the service ability of self-powered devices in complex environments, thermoelectric power generation devices should have stable and long-term temperature difference input (from a principle perspective) and good electricity storage ability (from an actual application perspective) to obtain higher durability and reliability and ensure the continuous operation of the Internet of Things. In the current form of temperature difference control, the hot end is directly input with heat flow, and the cold end dissipates heat passively, such as natural air convection. As the heat flow conducts along the bulk structure (such as a complex heat flow channel or a heat collection module), the temperature of the cold end rises, and the temperature difference between the cold and hot ends decreases. To extend the power supply time under the same design, it is necessary to increase the area or thickness of the bulk structure, which violates the original intention of flexibility in restricted scenarios (such as narrow spaces); if the cold end dissipates heat actively (such as circulating water cooling or forced air convection), although the power supply time is extended without changing the design, the water circulation system or the cooling fan requires additional power supply, which violates the original intention of self-power supply in remote scenarios (such as forests). Summary of the Invention

[0004] In order to overcome the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a self-powered device based on a thermal diode and an Internet of Things distributed sensor node. The whole device operates as an independent device to supply power to different nodes without manual intervention.

[0005] To achieve the above object, the self-powered device based on a thermal diode and the Internet of Things distributed sensor node of the present invention adopt the following technical solutions:

[0006] A self-powered device based on a thermal diode includes a heat / cold zone construction layer, a thermoelectric conversion layer, a boost device, and an energy storage device. The thermoelectric conversion layer, the boost device, and the energy storage device are all arranged on the heat / cold zone construction layer; the output end of the thermoelectric conversion layer is connected to the input end of the boost device, and the output end of the boost device is connected to the energy storage device; the heat / cold zone construction layer is composed of an array arrangement of N forward thermal diodes and N reverse thermal diodes at intervals, where N≥1; the thermoelectric conversion layer includes electrodes, N-type thermoelectric strips, and P-type thermoelectric strips; an N-type thermoelectric strip and a P-type thermoelectric strip are fixed above adjacent forward and reverse thermal diodes. One end of the N-type thermoelectric strip is located in the hot zone of the forward thermal diode, and the other end is located in the cold zone of the reverse thermal diode. The adjacent N-type thermoelectric strip and P-type thermoelectric strip are connected by electrodes.

[0007] Furthermore, the forward and reverse thermal diodes have the same structure. The forward thermal diode includes a mold and a filler. The mold is provided with a groove structure, and the filler is filled in the groove structure.

[0008] Furthermore, the groove structure extends inward along the A surface of the mold. The B surface of the mold has a boss. The A surface and the B surface are two opposite surfaces.

[0009] Furthermore, the groove structure includes a semi-circular pool and branched grooves connected to the semi-circular pool.

[0010] Furthermore, the width of the end of the branched groove connected to the semi-circular pool is denoted as d c , and the width of the end of the branched groove far from the semi-circular pool is denoted as D c , and Dc < dc.

[0011] Furthermore, the volume fraction f of the filler is 11.04% - 25.77%, and f = V 10 / (V 10 +V9), where V 10 is the volume of the filler, and V9 is the volume of the mold.

[0012] Furthermore, the ratio of the thermal conductivity of the filler to that of the mold is 215.38.

[0013] Furthermore, all the N-type thermoelectric strips and P-type thermoelectric strips in the N forward thermal diodes and N reverse thermal diodes are parallel to each other.

[0014] Furthermore, there is a gap between the forward heat diode and the reverse heat diode, and a flexible filler is provided at the gap.

[0015] An Internet of Things distributed sensor node includes the above self-power supply device, and the self-power supply device is used to supply power to the sensor node.

[0016] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0017] In the present invention, the heat / cold zone construction layer includes forward heat diodes and reverse heat diodes arranged at intervals, and the thermoelectric conversion layer includes electrodes, N-type thermoelectric bars and P-type thermoelectric bars; an artificial heat / cold zone construction layer is constructed by using the bidirectional heat transfer anisotropy of the heat diodes. After the heat flow passes through the heat / cold zone construction layer, a hot zone and a cold zone are respectively formed on the upper surfaces of the forward heat diode and the reverse heat diode. Based on the thermoelectric conversion principle, the thermoelectric conversion layer converts the non-zero temperature difference between the hot zone and the cold zone into electrical energy output for continuous power generation. Without increasing the size of the bulk structure and without forced convection at the cold end, a long-term and stable temperature difference input can be provided, and the heat flow direction between the heat / cold zones is always parallel to the arrangement direction of the thermoelectric material, and the integration of the structural unit is higher. Even the long-term non-high-temperature waste heat generated in a limited space scenario or the short-term high-temperature waste heat (such as a fire) generated in a remote scenario (such as a forest) can generate electricity, and the expandability in a space-limited scenario is stronger.

[0018] Since the operating voltage of the boost device is usually lower than 30% of the starting voltage, the self-power supply device can output a millivolt-level voltage for more than 20 minutes in a millimeter-level outer dimension. The long-term power supply ability reduces the requirements of the thermoelectric conversion layer for the boost device. At the same time, the volt-level voltage output by the boost device continuously accumulates in the energy storage device, which is beneficial to increasing the service life of the self-power supply device, and further increasing the durability and reliability of the self-power supply of the Internet of Things sensor node in a complex environment.

[0019] Furthermore, the width of one end of the branch groove connected to the semi-circular pool is denoted as d c , and the width of the end of the branch groove far from the semi-circular pool is denoted as D c , Dc < dc. When the heat flow flows from the small end to the large end of the decreasing slope periodic groove, the output heat flow of the reverse heat diode is the smallest, and the heat transfer difference from the forward heat diode with the same morphology is the largest, thereby making the output voltage U of the thermoelectric conversion layer out the largest.

[0020] Furthermore, the volume fraction of the filler is 11.04% - 25.77%, which is beneficial to forming a large heat transfer difference between the forward heat diode and the reverse heat diode, thereby increasing the output voltage of the thermoelectric conversion layer.

[0021] Furthermore, there is a matching relationship between the thermal conductivity of the high-thermal-conductivity filler and the low-thermal-conductivity mold that constitutes the thermal diode, avoiding unnecessary waste and additional costs.

[0022] Furthermore, all N-type thermoelectric strips and P-type thermoelectric strips in N forward thermal diodes and N reverse thermal diodes are parallel to each other, which is conducive to arranging a larger number of N-type thermoelectric strips and P-type thermoelectric strips and can obtain a larger output voltage.

[0023] Furthermore, a flexible filler is filled between the forward thermal diode and the reverse thermal diode, and the "hot / cold zone" construction layer of the self-powered device can be bent to match waste heat generation sources of different shapes.

[0024] A distributed Internet of Things sensor node based on a thermal diode proposed in the present invention is powered by a self-powered device, conforming to the development trend of the complex environment, dense nodes, large scale, and precise sensing data of distributed Internet of Things sensors, and is energy-saving, environmentally friendly, green and sustainable, with low dependence on manual operation and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a technical solution diagram for realizing self-power supply of a distributed Internet of Things sensor node;

[0026] Figure 2 is an integrated schematic diagram of the "hot / cold zone" construction layer, thermoelectric conversion layer, boost device, and energy storage device of the self-powered device;

[0027] Figure 3 is a schematic diagram of a 1×1 unit of the "hot / cold zone" construction layer of the self-powered device;

[0028] Figure 4 is a schematic diagram of different groove structures prefabricated in a low-thermal-conductivity mold;

[0029] Figure 5 is the thermoelectric conversion layer layout for a 2×2 unit facing the "hot / cold zone" construction layer;

[0030] Figure 6 is a schematic diagram of self-power supply for a fire monitoring sensor using short-term high-temperature waste heat in a remote scenario;

[0031] Figure 7 is a simulation demonstration result diagram of a specific embodiment of the self-powered device.

[0032] In the drawings: 1. Forward thermal diode, 2. Reverse thermal diode, 3. Electrode, 4. N-type thermoelectric strip, 5. P-type thermoelectric strip, 6. Flexible filler, 7. Boost device, 8. Energy storage device, 9. Mold, 10. Filler, 11 - Boss. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] To make the objectives and technical solutions of the present invention clearer and easier to understand, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more. In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected" and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0035] A self-powered device based on a thermal diode, comprising a forward thermal diode 1, a reverse thermal diode 2, an electrode 3, an N-type thermoelectric strip 4, a P-type thermoelectric strip 5, a flexible filler 6, a boosting device 7 and an energy storage device 8.

[0036] Refer to Figure 1 , which is a technical solution diagram for realizing self-power supply of an Internet of Things distributed sensor node. The self-powered device is installed on the surface of a heat-generating target such as a motor vehicle exhaust pipe, an industrial production device, etc. After the waste heat generated by the target vertically passes through the lower surfaces of the forward thermal diode 1 and the reverse thermal diode 2, a horizontal "hot zone" and a "cold zone" are respectively formed on the upper surfaces of the forward thermal diode 1 and the reverse thermal diode 2. The temperature of the hot zone is denoted as T out1 , and the temperature of the cold zone is denoted as T out2 ; based on the thermoelectric conversion principle (Seebeck effect), the non-zero temperature difference T out1 - T out2 between the "hot zone" and the "cold zone" is converted into an electric energy output U out ; the output electric energy U out (mV) is converted into available electric energy Us (V) is stored in the energy storage device 8 and then powers various sensor nodes.

[0037] Referring to Figure 2 , the self-powered device includes a "hot / cold zone" construction layer, a thermoelectric conversion layer, a boosting device 7, and an energy storage device 8. The thermoelectric conversion layer, the boosting device 7, and the energy storage device 8 are all arranged on the upper surface of the "hot / cold zone" construction layer. N forward thermal diodes 1 and N reverse thermal diodes 2 are arranged in an alternating array to form the bottom layer of the self-powered device - the "hot / cold zone" construction layer, where N≥1; the electrode 3, the N-type thermoelectric strip 4, and the P-type thermoelectric strip 5 form the upper layer of the self-powered device - the thermoelectric conversion layer. The output end of the thermoelectric conversion layer is connected to the input end of the boosting device 7, and the output end of the boosting device 7 is connected to the energy storage device 8. The boosting device 7 is a boost converter, and the energy storage device 8 is a device such as a capacitor that can store electrical energy.

[0038] The upper surfaces of adjacent forward thermal diodes 1 and reverse thermal diodes 2 are fixed with an N-type thermoelectric strip 4 and a P-type thermoelectric strip 5. One end of the N-type thermoelectric strip 4 is located in the hot zone of the forward thermal diode 1, and the other end is located in the cold zone of the reverse thermal diode 2. The N-type thermoelectric strip 4 and the P-type thermoelectric strip 5 are parallel and spaced apart from each other. Adjacent N-type thermoelectric strip 4 and P-type thermoelectric strip 5 are connected by the electrode 3. The startup threshold of the boosting device 7 is less than the output voltage U [[ID=X]] out ; the flexible filler 6 encapsulates the interval gaps between the forward thermal diodes 1 and the reverse thermal diodes 2 and the outer edge of the array, enabling the self-powered device to be bent to adapt to waste heat sources of different shapes.

[0039] The 1×1 unit of the "hot / cold zone" construction layer of the self-powered device is as Figure 3 shown. The forward thermal diode 1 and the reverse thermal diode 2 have the same structure and are collectively referred to as thermal diodes. The thermal diode is composed of a mold 9 prefabricated with a groove structure and a boss and a filler 10. The groove structure includes a semi-circular pool and a plurality of branched grooves communicating with the semi-circular pool. The groove structure extends downward along the A surface of the low-thermal-conductivity mold 9, and the high-thermal-conductivity filler 10 is filled in the groove structure. The B surface of the thermal diode has a boss 11, and the A surface and the B surface are two opposite surfaces. The length direction of the boss 11 is the same as that of the semi-circular pool; the height H of the boss p satisfies 0≤H p <H - R - L c , where H is the total height of the mold 9, H>0, and H can be taken as 8mm; R is the radius of the semi-circular pool, 0<R<H, and R can be taken as 3mm; L c is the length of the branched groove; the width W of the boss p is less than or equal to the diameter of the semi-circular pool, that is, 0≤W p ≤2R.

[0040] The forward heat diode 1 operates in the forward heat conduction state, i.e., the waste heat flows along the side where the filler 10 is located towards the side where the boss of the mold 9 is located, forming a "hot zone" on the upper surface of the forward heat diode 1; the reverse heat diode 2 operates in the reverse heat insulation state, i.e., the waste heat flows along the side where the boss of the mold 9 is located towards the side where the filler 10 is located, forming a "cold zone" on the upper surface of the reverse heat diode 2. When different groove structures with different morphologies and sizes are prefabricated in the mold 9, it will directly affect the volume fraction of the filler 10 filled in the groove structure; in addition, selecting different types of fillers 10 will directly affect the heat transfer difference T out1 -T out2 between the forward heat diode 1 and the reverse heat diode 2, thereby affecting the output voltage U of the thermoelectric conversion layer out .

[0041] Refer to Figure 4 , the schematic diagrams of different groove structures prefabricated in the mold. The same semi-circular pools and different branched grooves are prefabricated in the mold 9, and the slope of the branched groove is γ = (D c -d c ) / L c , d c is the width of the end where the branched groove is connected to the semi-circular pool, D c is the width of the end of the branched groove far from the semi-circular pool, L c is the length of the branched groove, and its morphology includes but is not limited to the equal-slope periodic grooves shown in (a) of Figure 4 , the increasing-slope periodic grooves shown in (b) of Figure 4 , the decreasing-slope periodic grooves shown in (c) of Figure 4 and the topologically irregular grooves shown in (d) of Figure 4 . For the equal-slope periodic grooves, D c = d c , γ = 0; for the increasing-slope periodic grooves, Dc > dc, γ > 0; for the decreasing-slope periodic grooves, Dc < dc, γ < 0, and the irregular grooves include branches arranged along the circumference of the semi-circular pool, and bifurcations are connected to the branches, and the bifurcations have tips

[0042] When the heat flow flows from the small end to the large end of the decreasing-slope periodic groove, the output heat flow of the reverse heat diode 2 is the smallest, and the heat transfer difference T out1 -T out2 with the forward heat diode 1 of the same morphology is the largest, thereby making the output voltage U out of the thermoelectric conversion layer the largest. The volume required for the high-thermal-conductivity filler 10 to completely fill the groove structure in the mold 9 is V 10 , the volume of the mold 9 is V9, then the volume fraction f of the filler 10 = V 10 / (V 10+V9), the value range of f is 11.04% to 25.77%. When f = 25.77%, it is beneficial for the forward heat diode 1 and the reverse heat diode 2 to form a large heat transfer difference T out1 -T out2 , thereby increasing the output voltage U of the thermoelectric conversion layer out .

[0043] For the different groove structures prefabricated in the mold 9, its dimensions include but are not limited to the branch groove length L c being 2.7 - 4.9 mm, the number of branch grooves being 4 - 12 branches, etc. When the volume fraction f of the filler 10 is the same, the decreasing slope periodic grooves with a shorter branch groove length and a smaller number of branch grooves are beneficial for the forward heat diode 1 and the reverse heat diode 2 to form a large heat transfer difference T out1 -T out2 , thereby making the output voltage U of the thermoelectric conversion layer out larger. For example, take the branch groove length of 2.7 mm and the number of branch grooves of 4 branches.

[0044] The ratio of the thermal conductivity of the high - thermal - conductivity filler 10 to the low - thermal - conductivity mold 9 is denoted as h, h = k 10 / k9>1, k 10 is the thermal conductivity of the filler 10, k9 is the thermal conductivity of the mold 9. When 1 < h < 215.38, the larger the h value, the greater the positive / negative heat transfer difference of the heat diode; when h > 215.38, increasing h has little effect on the output voltage of the thermoelectric conversion layer. That is, when the mold 9 selects a resin substrate and the filler 10 selects a liquid metal, k9 = 0.13 W / m·K, k 10 = 28 W / m·K, h = 215.38, which is beneficial for the forward heat diode 1 and the reverse heat diode 2 to form a large heat transfer difference, thereby making the output voltage of the thermoelectric conversion layer larger, and no additional cost and unnecessary waste will be generated.

[0045] The material of the mold 9 includes but is not limited to photocurable resin, PLA resin suitable for 3D printing technologies such as FDM, SLA, etc.; the material of the filler 10 is preferably thermal conductive silicone grease, liquid metal.

[0046] Refer to Figure 5 , and a 2×2 unit thermoelectric conversion layer layout is constructed facing the "hot / cold zone". Different array forms and array numbers of the forward heat diode 1 and the reverse heat diode 2 in the "hot / cold zone" construction layer directly affect the internal resistance and output voltage U of the self - power supply device out . The array forms include parallel arrays, vertical arrays, cross arrays, etc.

[0047] The parallel array is as shown in Figure 5 (a) below, and all the bosses are parallel to each other;

[0048] The vertical array is as shown in Figure 5 (b) below, where the bosses of adjacent thermal diodes alternate between parallel and perpendicular;

[0049] The cross array is as shown in Figure 5 (c) below, where the bosses of adjacent forward thermal diodes 1 and reverse thermal diodes 2 are all perpendicular to each other.

[0050] Among the three array forms, the parallel array is beneficial for arranging a larger number of N-type thermoelectric bars 4 and P-type thermoelectric bars 5, and a larger output voltage U can be obtained. out .

[0051] The number of arrays includes 1×1, 2×2, 3×3... N×N. The arrangement directions of the N-type thermoelectric bars 4 and P-type thermoelectric bars 5 in the thermoelectric conversion layer are always parallel to the temperature difference (T out1 -T out2 ) direction, that is, the heat flow direction formed by the "hot / cold zone" construction layer, and the external dimension of the self-powered device is in millimeters (mm) level, with a high integration per unit area.

[0052] Example 1

[0053] Referring to Figure 6 , the schematic diagram of self-power supply for a fire monitoring sensor using short-term high-temperature waste heat in a remote scenario. The self-powered device and the fire monitoring sensor are installed on trees in a remote scenario such as a forest, serving as an Internet of Things distributed sensor node. When the forest is in a normal state, that is, the environmental temperature is uniform and stable, the self-powered device shuts down; when there are abnormal states such as a fire in the forest, the short-term high-temperature waste heat brought by the fire will immediately pass through the lower surfaces of the forward thermal diode 1 and the reverse thermal diode 2, and then a horizontal "hot zone" and a "cold zone" are respectively formed on the upper surfaces of the forward thermal diode 1 and the reverse thermal diode 2. The temperature of the hot zone is denoted as T out1 , and the temperature of the cold zone is denoted as T out2 ; based on the thermoelectric conversion principle (Seebeck effect), the non-zero temperature difference T out1 -T out2 between the "hot zone" and the "cold zone" is immediately converted into electrical energy output U out ; the output electrical energy U out (mV) is converted into available electrical energy U s (V) by the boost device 7 and stored in the energy storage device 8, immediately supplying power to the fire monitoring sensor, and immediately sending an alarm to the monitoring platform based on the Internet of Things wireless communication technology to achieve pre-fire spread monitoring and early warning. When the fire is controlled and extinguished, the environmental temperature tends to be uniform and stable again, and the self-powered device will automatically shut down. The above-mentioned instantaneity based on thermoelectric power generation realizes the self-power supply of the sensor node in a normal state - shutdown, abnormal state - instant operation in a remote scenario (such as a forest).

[0054] The present invention uses low-grade waste heat existing in the environment (such as industrial emissions, moving motor vehicles, electronic components in working state, and body heat of biological tissues, etc.) as input energy, and converts it into available electrical energy output based on thermocouple units and the Seebeck effect, without pollution and wear. The device has a compact structure, strong dispersibility, and high flexibility, is suitable for restricted scenarios (such as narrow spaces), and the instantaneity of thermoelectric power generation is suitable for sensor nodes in remote scenarios (such as forests) in normal state - shutdown and abnormal state - instant operation, such as the self-power supply of forest fire monitoring sensor nodes.

[0055] Simulation experiment

[0056] Refer to Figure 7 , a simulation demonstration of a specific embodiment of the self-power supply device. In this embodiment, the cross array has an array number of 3×3, and the dimensions of the forward thermal diode 1 and the reverse thermal diode 2 are length×width×height of 16×16×8 mm 3 , the dimensions of the N-type thermoelectric bar 4 and the P-type thermoelectric bar 5 are equal, with length×width×height all being 1×1×5.5 mm 3 , the cross-sectional dimension of the electrode 3 is 1×1 mm 2 , the length is designed to connect the adjacent N-type thermoelectric material bars 4 and P-type thermoelectric material bars 5 at intervals. When the temperature difference is 60°C, the output voltage U of the thermoelectric conversion layer is measured by simulation out is 29.9 mV, which is higher than the startup threshold of 20 mV of the boost device 7. Taking a magnification factor of 1:100 as an example, the self-power supply device can output at least 2.99 V of voltage. This shows that the self-power supply device in the present invention can output a voltage at the volt level with a millimeter-scale outer dimension.

[0057] The present invention is based on thermoelectric materials and a boost device, converts infinitely low-grade environmental waste heat into volt-level voltage output, and then uses an energy storage device to continuously store the volt-level voltage, increasing the service life of the self-power supply device. The whole device operates independently as a device to supply power to different nodes, without manual intervention, without additional energy consumption, with low assembly cost, and is green and sustainable.

[0058] The above content is only to illustrate the technical idea of the present invention, and cannot limit the protection scope of the present invention. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A self-powered device based on a thermal diode, characterized in that, It includes a heat / cold zone construction layer, a thermoelectric conversion layer, a booster device (7), and an energy storage device (8). The thermoelectric conversion layer, the booster device (7), and the energy storage device (8) are all arranged on the heat / cold zone construction layer. The output end of the thermoelectric conversion layer is connected to the input end of the booster device (7), and the output end of the booster device (7) is connected to the energy storage device (8). The heat / cold zone construction layer is composed of an array arrangement of N forward heat diodes (1) and N reverse heat diodes (2) at intervals, where N≥1. The thermoelectric conversion layer includes electrodes (3), N-type thermoelectric strips (4), and P-type thermoelectric strips (5). The N-type thermoelectric strip (4) and the P-type thermoelectric strip (5) are fixed above the adjacent forward heat diode (1) and reverse heat diode (2). One end of the N-type thermoelectric strip (4) is located in the hot zone of the forward heat diode (1), and the other end is located in the cold zone of the reverse heat diode (2). The adjacent N-type thermoelectric strip (4) and P-type thermoelectric strip (5) are connected through the electrode (3).

2. The self-powered device based on a thermal diode according to claim 1, wherein The forward heat diode (1) and the reverse heat diode (2) have the same structure. The forward heat diode (1) includes a mold (9) and a filler (10). The mold (9) is provided with a groove structure, and the filler (10) is filled in the groove structure.

3. The self-powered device based on a thermal diode according to claim 2, characterized in that, The groove structure extends inward along the A surface of the mold (9). The B surface of the mold (9) has a boss (11). The A surface and the B surface are two opposite surfaces.

4. The self-powered device based on a thermal diode according to claim 2, wherein The groove structure includes a semi-circular pool and branched grooves connected to the semi-circular pool.

5. The self-powered device based on a thermal diode according to claim 4, wherein, The width of one end of the branched groove connected to the semi-circular pool is denoted as d c , and the width of the end of the branched groove away from the semi-circular pool is denoted as D c , where Dc < dc.

6. The self-powered device based on a thermal diode according to claim 2, wherein The volume fraction f of the filler (10) is 11.04% to 25.77%, and f = V 10 / (V 10 + V9), where V 10 is the volume of the filler (10) and V9 is the volume of the mold (9).

7. The self-powered device based on a thermal diode according to claim 2, characterized in that, The ratio of the thermal conductivity of the filler (10) to the mold (9) is 215.

38.

8. The self-powered device based on a thermal diode according to claim 1, characterized in that, All the N-type thermoelectric strips (4) and P-type thermoelectric strips (5) among the N forward heat diodes (1) and N reverse heat diodes (2) are parallel to each other.

9. The self-powered device based on a thermal diode according to claim 1, wherein There is a gap between the forward heat diode (1) and the reverse heat diode (2), and a flexible filler (6) is arranged at the gap.

10. An Internet of Things distributed sensor node includes the self-powered device according to any one of claims 1-9, and the self-powered device is used to supply power to the sensor node.

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