Design method of thermoelectric generator transducer module

Abstract

The application provides a design method of a transduction module of a thermoelectric generator. The transduction module comprises a heat preservation assembly and a plurality of thermoelectric devices. The design method comprises: obtaining a heat loss distribution diagram of the thickness of the heat preservation assembly changing with the heat loss according to a target conversion efficiency of the thermoelectric generator, a target output power of the thermoelectric generator and the heat power of all the thermoelectric devices; and determining the thickness of the heat preservation assembly according to the heat loss distribution diagram. The design method of the transduction module of the thermoelectric generator provided by the application can improve the situation that the design deviation of the size of the heat preservation assembly is large through experience, avoid the blindness and uncertainty caused by the selection of parameters depending on experience in the traditional method, improve the design accuracy of the transduction module, and make the design result more suitable for the actual working state.

Description

Technical Field

[0001] This application relates to the field of thermoelectric generator design technology, and in particular to a design method for a thermoelectric generator conversion module. Background Technology

[0002] An isotope thermoelectric generator is a device that converts the heat of isotope decay into electrical energy using thermoelectric devices based on the thermoelectric effect. The energy conversion module of the thermoelectric generator is the component that converts thermal energy into electrical energy; the energy conversion module typically consists of a heat distributor, thermoelectric devices, and insulation components.

[0003] In related technologies, the design of thermoelectric generators is usually based on given performance indicators (such as output power and conversion efficiency). The heat source is designed according to the output power, conversion efficiency and safety requirements. After the heat source is determined, the energy conversion module is designed. Currently, the design method for the energy conversion module is usually based on experience to design key parameters such as the length of the thermoelectric arm and the ratio of P-type to N-type electric arms. Parameters such as the cross-sectional area of ​​a single electric arm are calculated, and the size of the insulation component is preset according to experience. This method is prone to design deviations, resulting in a large deviation between the actual performance of the thermoelectric generator and the target, and poor design accuracy and reliability. Summary of the Invention

[0004] This application provides a design method for a thermoelectric generator's transducer module to improve the design accuracy and reliability of the thermoelectric generator's transducer module.

[0005] The technical solution of this application embodiment is implemented as follows: This application provides a design method for a transducer module of a thermoelectric generator. The transducer module includes an insulation component and multiple thermoelectric devices. The design method includes: Based on the target conversion efficiency of the thermoelectric generator, the target output power of the thermoelectric generator, and the thermal power of all the thermoelectric devices, obtain the heat loss distribution diagram of the thickness of the insulation component as a function of heat loss. The thickness of the insulation component is determined based on the heat loss distribution diagram.

[0006] In some embodiments, the insulation component includes an insulation end cap, the energy conversion module further includes a heat distributor, the hot end of the thermoelectric device is disposed on the outer surface of the heat distributor, the cold end of the thermoelectric device is in contact with the outer shell of the thermoelectric generator, and the insulation end cap is disposed on the end face of the heat distributor; the step of obtaining a heat loss distribution diagram of the thickness of the insulation component as a function of heat loss based on the target conversion efficiency of the thermoelectric generator, the target output power of the thermoelectric generator, and the thermal power of all the thermoelectric devices includes: The target total thermal power of the thermoelectric generator is obtained by the ratio of the target output power of the thermoelectric generator to the target conversion efficiency of the thermoelectric generator. Based on the Fourier heat conduction formula, the integral average of the thermal conductivity of the insulation end cap material in the hot and cold end temperature ranges, and the area of ​​the insulation end cap, a formula for calculating the heat power flowing through the insulation end cap is obtained. Based on the formula for calculating the heat power flowing through the insulation end cap, a heat loss distribution diagram of the insulation end cap is obtained.

[0007] In some embodiments, the insulation component further includes a fan-shaped insulation block, the thermoelectric device includes multiple thermocouples, each thermocouple includes a P-type arm and an N-type arm, the inner sidewall of the fan-shaped insulation block is disposed on the outer periphery of the heat distributor, and the fan-shaped insulation block is located between two adjacent thermoelectric devices, and the step of determining the thickness of the insulation component according to the heat loss distribution diagram includes: The thickness of the insulation end cap is determined based on the heat loss distribution diagram of the insulation end cap; The diameter of the insulation end cap is determined based on the outer diameter of the heat distributor. The heat power flowing through the insulation end cap is obtained based on the determined thickness of the insulation end cap and the heat power calculation formula. The thermal power of all thermoelectric devices in the thermoelectric generator is obtained based on the thermal power flowing through a single thermocouple, the number of thermocouples in a single thermoelectric device, and the number of thermoelectric devices in the thermoelectric generator. Based on the principle of energy conservation, and combining the target total thermal power of the thermoelectric generator, the thermal power of all the thermoelectric devices, and the thermal power flowing through the insulation end cap, the thermal power flowing through the fan-shaped insulation block is obtained. Based on the formula for calculating the heat power flowing through the sector-shaped insulation block, the thickness of the sector-shaped insulation block is obtained according to the heat power flowing through the sector-shaped insulation block and the determined inner arc length of the sector-shaped insulation block.

[0008] In some embodiments, the formula for calculating the heat power flowing through the fan-shaped insulation block is: ——(1) in, The thermal power of the fan-shaped insulation block. This refers to the hot-junction temperature of the thermoelectric device. This refers to the cold junction temperature of the thermoelectric device. It is the integral average value of the thermal conductivity of the insulation material in the temperature range between the hot and cold ends, where t is the inner arc length of the sector-shaped insulation block. The outer radius of the sector-shaped insulation block. Let be the inner radius of the sector-shaped insulation block.

[0009] In some embodiments, the design method further includes: The number of thermocouples in a single branch of a single thermoelectric device is obtained based on the integral average of the Seebeck coefficient between the hot end temperature and the cold end temperature, the determined open-circuit voltage of the thermoelectric generator, the determined number of branches in each thermoelectric device, and the determined number of thermoelectric devices in the thermoelectric generator. The number of thermocouples in a single thermoelectric device is obtained based on the number of thermocouples in a single branch of a single thermoelectric device and the determined number of branches in a single thermoelectric device.

[0010] In some embodiments, the design method further includes: The thermal power flowing through a single thermocouple is obtained based on the cross-sectional area of ​​the N-type thermocouple, the cross-sectional area of ​​the P-type thermocouple, the length of the N-type thermocouple, the length of the P-type thermocouple, the integral average thermal conductivity of the material of the N-type thermocouple in the hot-end and cold-end temperature ranges, the integral average thermal conductivity of the material of the P-type thermocouple in the hot-end and cold-end temperature ranges, the current flowing through a single thermocouple, the total resistance of a single thermocouple, the hot-end and cold-end temperature ranges, the Seebeck coefficient of the material of the N-type thermocouple at the hot-end temperature, and the Seebeck coefficient of the material of the P-type thermocouple at the hot-end temperature.

[0011] In some embodiments, the method for obtaining the length of the N-type electric arm, the length of the P-type electric arm, and the hot-end temperature and cold-end temperature range includes: Based on the formula for calculating the maximum conversion efficiency of a single thermocouple, and using the arm length of the single thermocouple and the hot-end and cold-end temperature ranges of the thermoelectric device as variables, a first efficiency distribution map of the thermoelectric device is obtained. Based on the first efficiency distribution diagram, the length of the N-type electric arm, the length of the P-type electric arm, and the hot-end temperature and cold-end temperature range are determined.

[0012] In some embodiments, the thermoelectric device further includes an electrode that contacts the N-type arm and the P-type arm to form an electrical connection between the N-type arm and the P-type arm. The step of obtaining the formula for calculating the maximum conversion efficiency includes: Based on the integral average resistivity of the N-type and P-type electric arms in the hot-end and cold-end temperature ranges, the cross-sectional area of ​​the N-type electric arm, the cross-sectional area of ​​the P-type electric arm, the length of the N-type electric arm, and the length of the P-type electric arm, the resistance calculation formulas for the N-type and P-type electric arms are obtained: ——(2) ——(3) In the formula, The resistance of the N-type electric arm, The resistance of the P-type electric arm, The resistivity of the material of the N-type electric arm is the integral average value of the resistivity in the hot-end and cold-end temperature ranges. Let L be the integral average resistivity of the material of the P-type electric arm across the hot-end and cold-end temperature ranges, and L be the length of the P-type electric arm and the length of the N-type electric arm. The cross-sectional area of ​​the N-type electric arm is... The cross-sectional area of ​​the P-type electric arm; The interfacial resistivity of the N-type electrode arm and the electrode plate and the interfacial resistivity of the P-type electrode arm and the electrode plate are set to be equal. Based on the interfacial resistivity of the N-type electrode arm and the P-type electrode arm and the electrode plate, the cross-sectional area of ​​the N-type electrode arm and the cross-sectional area of ​​the P-type electrode arm, the formula for calculating the interfacial contact resistance of a single electrode coupler is obtained: ——(4) In the formula, The interfacial contact resistance between a single thermocouple and the electrode plate. The interface resistivity between the N-type arm or P-type arm of a single thermocouple and the electrode; Based on the resistance calculation formulas for the N-type electric arm, the P-type electric arm, and the interface contact resistance calculation formula between a single thermocouple and the electrode, the total resistance calculation formula for a single thermocouple is obtained: ——(5) In the formula, The total resistance of a single thermocouple; Based on the integral average of the Seebeck coefficient between the hot and cold junction temperatures, the temperature range between the hot and cold junctions, and the external load resistance, the formulas for calculating the open-circuit voltage and open-circuit current of a single thermocouple generated by the Seebeck effect are obtained: ——(6) ——(7) In the formula, The open-circuit voltage of a single said thermocouple, It is the sum of the absolute values ​​of the integral average of the Seebeck coefficients of the materials of the N-type electric arm and the P-type electric arm between the hot-end temperature and the cold-end temperature. The hot-junction temperature of the thermoelectric device. I represents the cold junction temperature of the thermoelectric device, and I represents the open-circuit current of a single thermocouple. The external load resistor; Based on the determined external load resistance, the formula for calculating the open-circuit voltage of a single thermocouple, and the formula for calculating the open-circuit current of a single thermocouple, the formula for calculating the output power of a single thermocouple is obtained: ——(8) In the formula, The output power of the single thermocouple; Based on the Fourier heat conduction formula, the Peltier effect formula, and the Joule heating formula, the formula for calculating the input heat power of a single thermocouple is obtained: ——(9) In the formula, The input thermal power of a single said thermocouple, For Fourier thermal conductivity, For Peltier thermal power, Joule heat power, The sum of the absolute values ​​of the Seebeck coefficients of the materials of the N-type electric arm and the P-type electric arm at the hot-end temperature. The integral average value of the thermal conductivity of the material of the N-type electric arm in the hot-end and cold-end temperature ranges is given. The integral average value of the thermal conductivity of the material of the P-type electric arm in the hot-end temperature and cold-end temperature range; The calculation formula for the output power of a single thermocouple is compared with the calculation formula for the input heat power of a single thermocouple, and combined with formulas (2) to (9), the calculation formula for the conversion efficiency of a single thermocouple is obtained: ——(10) In the formula, The conversion efficiency of a single said couple; The external load resistor is set to be equal to the total resistance of a single thermocouple, and the formula for calculating the maximum conversion efficiency of a single thermocouple is obtained: ——(11) in, This represents the maximum conversion efficiency of the thermoelectric device. The resistivity of the N-type electric arm, denoted as the resistivity of the P-type electric arm, and m is the ratio of the cross-sectional area of ​​the N-type electric arm to that of the P-type electric arm.

[0013] In some embodiments, a method for obtaining the total resistance of a single said thermocouple includes: The total resistance of the thermoelectric generator is obtained based on the target output power and target open-circuit voltage of the thermoelectric generator. The total resistance of a single thermocouple is obtained based on the total resistance of the thermoelectric generator, the determined number of thermoelectric devices, and the number of thermocouples in each thermoelectric device.

[0014] In some embodiments, the method for obtaining the cross-sectional area of ​​the N-type electric arm and the cross-sectional area of ​​the P-type electric arm includes: Based on the formula for calculating the maximum conversion efficiency of a single thermocouple, and taking into account the cold junction temperature of the thermoelectric device, the determined length of the N-type arm, the determined length of the P-type arm, and the determined hot junction temperature and cold junction temperature range, a second efficiency distribution map is obtained, using the cross-sectional area ratio of the N-type arm to the P-type arm of the thermoelectric device as a variable. Based on the second efficiency distribution map, the cross-sectional area ratio value of the N-type arm to the P-type arm is obtained. Combining formulas (2), (3), (4), and (5), and based on the total resistance of a single thermocouple, the average resistivity of the N-type and P-type thermocouples in the hot-end and cold-end temperature ranges, the interfacial resistivity of the P-type thermocouple and the electrode, the interfacial resistivity of the N-type thermocouple and the electrode, and the ratio of the cross-sectional areas of the N-type and P-type thermocouples, the cross-sectional area of ​​the N-type thermocouple and the cross-sectional area of ​​the P-type thermocouple are obtained.

[0015] The design method for the transducer module of the thermoelectric generator provided in this application obtains a heat loss distribution map of the thickness of the insulation component as heat loss changes, and determines the thickness of the insulation component based on the heat loss distribution map and a reasonable range of heat loss. This method can improve the situation where the design deviation is large due to the design of the insulation component size based on experience, avoid the blindness and uncertainty brought about by the traditional method of relying on experience to select parameters, improve the design accuracy of the transducer module, and make the design result more in line with the actual working state. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a thermoelectric generator in one embodiment of this application; Figure 2 for Figure 1 Sectional view at point AA; Figure 3 for Figure 1 Sectional view at point BB; Figure 4 This is a cross-sectional view of a thermoelectric generator according to an embodiment of this application; Figure 5 A graph showing the distribution of the thermoelectric conversion efficiency of a single thermocouple as a function of arm length and temperature difference, provided in an embodiment of this application. Figure 6A graph showing the distribution of the thermoelectric conversion efficiency of a single thermocouple provided in an embodiment of this application as a function of the cross-sectional area ratio of the N-type and P-type thermocouples. Figure 7 A heat loss distribution diagram showing the change in thickness of the thermal insulation component as a function of heat loss, provided in an embodiment of this application; Figure 8 A first flowchart illustrating the design method of a thermoelectric generator conversion module provided in an embodiment of this application; Figure 9 A second flowchart illustrating the design method of the energy conversion module of a thermoelectric generator provided in an embodiment of this application; Figure 10 A third flowchart illustrating the design method of the energy conversion module of a thermoelectric generator provided in an embodiment of this application; Figure 11 A fourth flowchart illustrating the design method of the energy conversion module of a thermoelectric generator provided in an embodiment of this application; Figure 12 A fifth flowchart illustrating the design method of the energy conversion module of a thermoelectric generator provided in an embodiment of this application; Figure 13 A sixth flowchart illustrating the design method of the energy conversion module of a thermoelectric generator provided in an embodiment of this application; Figure 14 A seventh flowchart illustrating the design method of the transducer module for a thermoelectric generator provided in an embodiment of this application. Figure 15 This is a schematic diagram of the eighth step in the design method of the energy conversion module of a thermoelectric generator provided in an embodiment of this application.

[0017] Explanation of reference numerals in the attached figures 10. Thermoelectric generator; 11. Housing; 12. Energy transducer module; 121. Insulation component; 1211. Insulation end cap; 1212. Fan-shaped insulation block; 122. Thermoelectric device; 1221. Electrocouple; 1221a. P-type electric arm; 1221b. N-type electric arm; 1222. Electrode; 123. Heat distributor. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] An isotope thermoelectric generator is a device that converts the heat of isotope decay into electrical energy using thermoelectric devices based on the thermoelectric effect. The energy conversion module of the thermoelectric generator is the component that converts thermal energy into electrical energy; the energy conversion module typically consists of a heat distributor, thermoelectric devices, and insulation components.

[0020] The thermoelectric conversion efficiency of a transducer module is typically determined by the conversion efficiency of the thermoelectric device and the system's thermal efficiency. The conversion efficiency of the thermoelectric device is influenced by factors such as the thermoelectric properties of the thermoelectric material, the arm length, the ratio of the cross-sectional areas of the P-type and N-type arms, and the temperature difference between the cold and hot ends of the thermoelectric device. The system's thermal efficiency depends on the design of the insulation components. Due to the Seebeck and Peltier effects of thermoelectric materials, there is a strong coupling effect between heat and electricity; any change in design parameters will trigger a series of chain reactions, causing the actual performance to deviate from the design target.

[0021] Currently, there is no simple and effective design method for thermoelectric converter modules. Typically, design is based on experience, pre-setting key parameters such as the arm length of the thermoelectric device, calculating the number of N-type and P-type arms based on requirements such as the operating temperature difference and the open-circuit voltage of the thermoelectric generator, assuming system thermal efficiency, calculating the effective heat flowing through the thermoelectric device, calculating the total heat transfer area of ​​the N-type and P-type arms using the Fourier heat conduction equation, and then calculating the cross-sectional area of ​​a single arm based on the previously calculated number of arms. Finally, the dimensions of the insulation component are pre-set based on experience. This method ignores thermoelectric coupling effects such as the Peltier effect and Joule heating effect. This method is only suitable for static conditions with no current flowing. However, during actual power generation, the Peltier effect absorbs heat at the hot end, and some Joule heating returns to the hot end. Therefore, using this method introduces significant design deviations.

[0022] Based on this, this application provides a design method for the transducer module of a thermoelectric generator 10. Please refer to [link to relevant documentation]. Figures 1 to 8 The transducer module 12 includes an insulation component 121 and multiple thermoelectric devices 122. The design method includes: S40: Based on the target conversion efficiency of the thermoelectric generator, the target output power of the thermoelectric generator, and the thermal power of all thermoelectric devices, obtain the heat loss distribution diagram of the insulation component thickness as a function of heat loss.

[0023] S50: Determine the thickness of the insulation component based on the heat loss distribution diagram.

[0024] It should be noted that the thermoelectric generator 10 includes a transducer module 12, which comprises an insulation component 121 and multiple thermoelectric devices 122. Thermoelectric devices 122 refer to components that convert thermal energy into electrical energy through the Seebeck effect. The Seebeck effect, also known as the first thermoelectric effect, refers to the thermoelectric phenomenon caused by the temperature difference between two different conductors or semiconductors, resulting in a voltage difference between them. Generally, the direction of the thermoelectric potential is defined as: electrons flow from negative to positive at the hot end.

[0025] The thermoelectric device 122 has a cold end and a hot end. The hot end is the end of the thermoelectric device 122 that is in contact with a high-temperature heat source and has a higher temperature. Its core function is to absorb heat and drive charge carriers (electrons or holes) to generate a potential difference through the temperature difference between the hot end and the cold end, thereby realizing the conversion of thermal energy into electrical energy. The cold end is the end of the thermoelectric device 122 that has a lower temperature.

[0026] The insulation component 121 is used to insulate the thermoelectric device 122. Exemplarily, the insulation component 121 covers the thermoelectric device 122.

[0027] In addition, the thermoelectric generator 10 typically includes a housing 11 and a heat source module (not shown), wherein the heat source module generates heat through the decay of a radioactive isotope and provides heat to the hot end of the transducer module 12, specifically the thermoelectric device 122. For example, the radioactive isotope in the heat source module is a mega-curie-level β-radioactive source.

[0028] The thermoelectric generator 10 of this application can be used in underwater or marine environments. Specifically, the thermoelectric generator 10 can be applied to any type of underwater equipment, such as underwater or deep-sea monitoring equipment, underwater or deep-sea exploration devices, etc.

[0029] In step S40, the target conversion efficiency and target output power of the thermoelectric generator 10 are both known parameters. Based on the ratio of the target output power to the target conversion efficiency of the thermoelectric generator 10, the target total thermal power of the thermoelectric generator 10 can be obtained.

[0030] According to the principle of energy conservation, the target total thermal power of the thermoelectric generator 10 is equal to the sum of the thermal power of all thermoelectric devices 122 and the heat flowing through the insulation component 121.

[0031] Therefore, when the thermal power of all thermoelectric devices 122 is determined, the amount of heat flowing through the insulation component 121 is determined.

[0032] In the heat loss distribution diagram of the thickness of the insulation component 121 as a function of heat loss, the thickness of the insulation component 121 is on one coordinate, and the heat loss of the insulation component 121 is on another coordinate.

[0033] The design method for the transducer module 12 of the thermoelectric generator 10 provided in this application embodiment obtains a heat loss distribution map of the thickness of the insulation component 121 as heat loss changes, and determines the thickness of the insulation component 121 based on the heat loss distribution map and a reasonable range of heat loss. This method can improve the situation where the design deviation is large due to the design of the insulation component 121 size by relying on experience, avoid the blindness and uncertainty brought about by the traditional method of relying on experience to select parameters, improve the design accuracy of the transducer module 12, and make the design result more in line with the actual working state.

[0034] In some embodiments, please refer to Figures 1 to 4 , Figure 7 , Figure 9 The insulation component 121 includes an insulation end cap 1211. The transducer module 12 also includes a heat distributor 123. The hot end of the thermoelectric device 122 is disposed on the outer surface of the heat distributor 123. The cold end of the thermoelectric device 122 is in contact with the outer casing 11 of the thermoelectric generator 10. The insulation end cap 1211 is disposed on the end face of the heat distributor 123. The step of obtaining a heat loss distribution diagram of the thickness of the insulation component 121 as a function of heat loss based on the target conversion efficiency of the thermoelectric generator 10, the target output power of the thermoelectric generator 10, and the heat power of all thermoelectric devices 122 includes: S41: Obtain the target total thermal power of the thermoelectric generator based on the ratio of the target output power of the thermoelectric generator to the target conversion efficiency of the thermoelectric generator.

[0035] S42: Based on the Fourier heat conduction formula, the integral average of the thermal conductivity of the insulation end cap material in the hot end temperature and cold end temperature range, and the area of ​​the insulation end cap, obtain the formula for calculating the heat power flowing through the insulation end cap, and obtain the heat loss distribution diagram of the insulation end cap based on the formula for calculating the heat power flowing through the insulation end cap.

[0036] It should be noted that the number of heat-insulating end caps 1211 is not limited. The heat-insulating end caps 1211 are disposed on the end face of the heat distributor 123, specifically on the axial end face of the heat distributor 123. The axial direction generally refers to cylindrical objects, that is, the direction of the cylinder's central axis of rotation, i.e., the direction common to the central axis. For example, Figure 1 and Figure 2 R1 in the figure can be an axial direction, specifically the axial direction of the thermoelectric generator 10 and the axial direction of the heat distributor 123.

[0037] The heat-insulating end cap 1211 can be set on one or both end faces of the heat distributor 123 along the axial direction, without any limitation.

[0038] For example, the heat distributor 123 is cylindrical or prismatic.

[0039] The hot end of the thermoelectric device 122 is located on the outer side of the heat distributor 123, which means that the outer periphery of the heat distributor 123 has multiple heat transfer areas, and each heat transfer area is in contact with the hot end of at least one thermoelectric device 122, so that the heat distributor 123 can transfer heat to each thermoelectric conversion device.

[0040] The cold end of the thermoelectric device 122 is in contact with the outer casing 11 of the thermoelectric generator 10. The area outside the outer casing 11 is an underwater environment, which provides a lower temperature for the cold end of the thermoelectric device 122. The cold end of the thermoelectric device 122 can also discharge waste heat through the outer casing 11 to the underwater environment. At the same time, it provides a working temperature difference for the thermoelectric device 122 to achieve thermoelectric conversion.

[0041] It should be noted that, in order to improve the insulation effect of the insulation end cap 1211 on the thermoelectric device 122, the insulation end cap 1211 can be extended radially outward to completely cover the thermoelectric device 122.

[0042] In step S42, the formula for calculating the heat power (heat) flowing through the insulation end cap 1211 is: ——(12) In the above formula (12), The thermal power of the insulation end cap 1211 is given by π, where π is the mathematical constant pi. The radius of the insulation end cap 1211, For the thickness of the insulation end cap 1211, The hot junction temperature of thermoelectric device 122 The cold junction temperature of thermoelectric device 122 It is the integral average value of the thermal conductivity of the insulation material in the temperature range between the hot end and the cold end.

[0043] It is understandable that heat loss is the loss of heat, which is equal to the heat or thermal power flowing through the insulation end cover 1211. The insulation end cover 1211 is installed on the end face of the heat distributor 123. Therefore, the radius of the insulation end cover 1211 can be determined by the size of the heat distributor 123. Under the premise that the radius of the insulation end cover 1211, the hot and cold end temperatures of the thermoelectric device 122, and the integral average value of the thermal conductivity of the insulation end cover 1211 material in the hot and cold end temperature ranges are all known parameters, the relationship between heat loss (thermal power of the insulation end cover 1211) and the thickness of the insulation end cover 1211 can be obtained.

[0044] For example, the heat loss varies with the thickness of the insulation end cap 1211 as follows: Figure 7 As shown.

[0045] In this embodiment, step S41 allows the acquisition of the target total thermal power of the thermoelectric generator 10, preparing for subsequent design steps. Step S42 first obtains the formula for calculating the thermal power flowing through the insulation end cap 1211, and then, by determining parameters other than the thickness of the insulation end cap 1211 and the thermal power flowing through it, a relationship diagram between heat loss (thermal power of the insulation end cap 1211) and the thickness of the insulation end cap 1211 is obtained. This provides a basis for designing the thickness of the insulation end cap 1211, improving the accuracy and reliability of the thickness design.

[0046] In some embodiments, please refer to Figure 3 , Figure 10 and Figure 11 The insulation component 121 also includes a fan-shaped insulation block 1212. Thermoelectric devices 122 include multiple thermocouples 1221. Each thermocouple 1221 includes a P-type arm 1221a and an N-type arm 1221b. The inner sidewall of the fan-shaped insulation block 1212 is disposed on the outer periphery of the heat distributor 123, and the fan-shaped insulation block 1212 is located between two adjacent thermoelectric devices 122. The step of determining the thickness of the insulation component 121 according to the heat loss distribution diagram includes: S51: Determine the thickness of the insulation end cap based on the heat loss distribution diagram of the insulation end cap.

[0047] S52: Determine the diameter of the insulation end cap based on the outer diameter of the heat distributor, and obtain the heat power flowing through the insulation end cap according to the determined thickness of the insulation end cap and the heat power flowing through the insulation end cap.

[0048] S53: Obtain the thermal power of all thermoelectric devices in the thermoelectric generator based on the thermal power flowing through a single thermocouple, the number of thermocouples in a single thermoelectric device, and the number of thermoelectric devices in the thermoelectric generator.

[0049] S54: Based on the principle of energy conservation, and combining the target total heat power of the thermoelectric generator, the heat power of all thermoelectric devices, and the heat power flowing through the insulation end cover, obtain the heat power flowing through the fan-shaped insulation block.

[0050] S55: Based on the formula for calculating the heat power flowing through the sector-shaped insulation block, the thickness of the sector-shaped insulation block is obtained according to the heat power flowing through the sector-shaped insulation block and the determined inner arc length of the sector-shaped insulation block.

[0051] It should be noted that the P-type electric arm 1221a and the N-type electric arm 1221b are two complementary semiconductor conductive structures used in the thermoelectric device 122. The P-type uses holes as the majority carriers, and the N-type uses electrons as the majority carriers. The two are connected in series to form a basic thermocouple pair 1221. The P-type electric arm 1221a and the N-type electric arm 1221b are electrically connected in series and thermally connected in parallel through a metal conductor (e.g., electrode 1222).

[0052] In a thermoelectric device 122, multiple thermocouples 1221 are connected in series. The P-type arm 1221a of one thermocouple 1221 and the N-type arm 1221b of another thermocouple 1221 are connected by a metal conductor, thereby realizing P, N, P, N connected in series to form a circuit. A thermoelectric device 122 can be composed of a single circuit or multiple parallel circuits (i.e., multiple parallel branches), and there is no limitation here.

[0053] The multiple or multiple channels mentioned in the embodiments of this application refer to two or more channels.

[0054] It is understandable that the cold and hot ends of the thermoelectric device 122 are the same as the cold and hot ends of the thermocouple 1221, the P-type electric arm 1221a, and the N-type electric arm 1221b.

[0055] In this application, the projection of the fan-shaped insulation block 1212 onto a cross section perpendicular to the axial direction can be a fan shape or a fan ring, and there is no specific limitation.

[0056] For example, the projection of the fan-shaped insulation block 1212 onto a cross section perpendicular to the axial direction is a fan shape, which is a figure enclosed by an arc and two radii passing through the two ends of the arc.

[0057] For example, the heat distributor 123 has a hollow prism structure, that is, the projection of the heat distributor 123 on a cross section perpendicular to the axial direction is a regular polygon. Each side of the regular polygon is provided with a heat transfer area and is used to connect a thermoelectric device 122. Therefore, the inner sidewall of the fan-shaped heat insulation block 1212 is provided on the outer periphery of the heat distributor 123, and the fan-shaped heat insulation block 1212 is located between two adjacent thermoelectric devices 122. Specifically, the inner sidewall of the fan-shaped heat insulation block 1212 can be provided at the intersection of two adjacent sides of the regular polygon. The fan-shaped heat insulation block 1212 contacts the heat distributor 123 and the two adjacent thermoelectric devices 122 respectively, thereby insulating the thermoelectric devices 122 and the heat distributor 123 and slowing down the rate of heat loss.

[0058] Understandably, the number of sector-shaped insulation blocks 1212 depends on the number of thermoelectric devices 122 connected to a heat distributor 123 and the number of heat distributors 123.

[0059] The number of heat distributors 123 can be one or more, and there is no limit to this.

[0060] The "multiple" mentioned in the embodiments of this application refers to two or more.

[0061] When there are multiple heat distributors 123, the multiple heat distributors 123 can be arranged along the axial direction. For example, the fan-shaped insulation block 1212 In step S51, the appropriate thickness of the insulation end cap 1211 can be selected based on the inflection point on the curve in the heat loss distribution diagram of the insulation end cap 1211.

[0062] For example, the thickness of the insulation end cap 1211 corresponding to the heat loss distribution curve in the heat loss range of 10%-20% is selected as the design reference, and the final design value is selected within the range of the insulation end cap 1211 thickness.

[0063] For example, the thickness of the insulation end cap 1211 can be the axial dimension of the insulation end cap 1211.

[0064] In step S52, the diameter of the insulation end cap 1211 is determined based on the outer diameter of the heat distributor 123. Specifically, the outer diameter parameter of the heat distributor 123 can be directly used as the diameter parameter of the insulation end cap 1211, or the sum of the outer diameter parameter of the heat distributor 123 and the length of the electric arm of the thermoelectric device 122 can be used as the diameter parameter of the insulation end cap 1211. There is no limitation here.

[0065] It is understandable that the sum of the outer diameter parameter of the heat distributor 123 and the length of the electric arm of the thermoelectric device 122 is used as the diameter parameter of the insulation end cover 1211. This corresponds to the case where the insulation end cover 1211 extends beyond the heat distributor 123 and extends to the cold end of the thermoelectric device 122. Here, the insulation end cover 1211 only extends radially to the corresponding position of the cold end on the end face of the heat distributor 123, and does not extend to the space between the outer shell 11 and the cold end, so that the cold end can directly contact the outer shell 11 and discharge waste heat to the outside through the outer shell 11.

[0066] Here, by determining the diameter of the insulation end cap 1211 and the thickness of the insulation end cap 1211 determined in step S51, the design parameters of the insulation end cap 1211 can be determined. Based on the calculation formula of the heat power (heat) flowing through the insulation end cap 1211 obtained in step S42, the actual heat power flowing through the insulation end cap 1211 under the determined insulation end cap 1211 parameters can be calculated, thus providing a basis for subsequent design.

[0067] In step S53, the formula for calculating the thermal power of all thermoelectric devices 122 in the thermoelectric generator 10 is: ——(13) In formula (13), y represents the thermal power of all thermoelectric devices 122; y represents the number of branches in a single thermoelectric device 122; n represents the number of thermocouples 1221 in a single branch; b represents the number of thermoelectric devices 122 in the thermoelectric generator 10. The heat power flowing through a single thermocouple 1221.

[0068] Given the parameters such as the number of branches in a thermoelectric device 122, the number of thermocouples 1221 in a single branch, the number of thermoelectric devices 122 in the thermoelectric generator 10, and the heat power flowing through a single thermocouple 1221, the heat power of all thermoelectric devices 122 in the thermoelectric generator 10 can be obtained according to formula (13). .

[0069] In step S54, according to the law of conservation of energy, the heat power flowing through the sector-shaped insulation block 1212 is: ——(14) In formula (14), The heat power flowing through the fan-shaped insulation block 1212; This represents the target total thermal power of the thermoelectric generator 10. It is understood that there can be multiple sector-shaped insulation blocks 1212, and the thermal power flowing through these sector-shaped insulation blocks 1212 is... This refers to the heat power flowing through all the sector-shaped insulation blocks 1212 in the transducer module 12. The heat power flowing through the insulation end cap 1211. This refers to the heat power flowing through the heat insulation end cap 1211 on the axial side of the heat distributor 123. The heat insulation end cap 1211 on the axial side of the heat distributor 123 can be one or more, without limitation.

[0070] Given that the thermal power of all thermoelectric devices 122 is determined, the thermal power flowing through the fan-shaped end cap is determined, and the target total thermal power of the thermoelectric generator 10 is known, the thermal power flowing through the fan-shaped insulation block 1212 can be obtained according to formula (14).

[0071] In step S55, based on the Fourier heat transfer formula, the heat power flowing through the sector-shaped insulation block 1212 is calculated as follows: ——(1) In formula (1), The thermal power of the fan-shaped insulation block 1212 The hot junction temperature of thermoelectric device 122 The cold junction temperature of thermoelectric device 122 It is the integral average value of the thermal conductivity of the insulation material in the temperature range between the hot end and the cold end, and t is the inner arc length of the sector-shaped insulation block 1212. The outer radius of the fan-shaped insulation block 1212 is... Let be the inner radius of the fan-shaped insulation block 1212. This represents the logarithm of the ratio of the outer radius to the inner radius of the sector-shaped insulation block 1212, with base e. Let e ​​be the natural logarithm of the ratio of the outer radius to the inner radius of the sector-shaped insulation block 1212, and let e be the natural constant, e≈2.718281828459.

[0072] For example, the projection of the sector-shaped insulation block 1212 onto a cross-section perpendicular to the axial direction is a sector ring, where the sector ring refers to the portion of the ring truncated by a sector shape, formed by two concentric circular arcs and two radii. The outer radius of the sector-shaped insulation block 1212 refers to the radius of the circle containing the outer arc of its projection onto the cross-section perpendicular to the axial direction. The inner radius of the sector-shaped insulation block 1212 refers to the radius of the circle containing the inner arc of its projection onto the cross-section perpendicular to the axial direction. The inner arc length of the sector-shaped insulation block 1212 refers to the arc length of the inner arc of its projection onto the cross-section perpendicular to the axial direction.

[0073] It should be noted that the inner diameter and inner arc length of the sector-shaped insulation block 1212 can both be determined by the dimensions of the heat distributor 123 and the thermoelectric device 122. For example, the inner diameter of the sector-shaped insulation block 1212 is equal to the outer diameter of the heat distributor 123, and the inner arc length of the sector-shaped insulation block 1212 is equal to the outer perimeter of the projected outline of the heat distributor 123 on a cross section perpendicular to the axial direction minus the sum of the contact dimensions of all thermoelectric devices 122 on the outer peripheral surface of the heat distributor 123. The difference between the hot end temperature and the cold end temperature of the thermoelectric device 122 is a known parameter. The integral average value of the thermal conductivity of the insulation material in the hot end temperature and cold end temperature range is determined based on the insulation material. When the above parameters are determined and the thermal power of the fan-shaped insulation block 1212 is also confirmed, the outer diameter or outer radius parameter of the fan-shaped insulation block 1212 can be calculated according to formula (1). The thickness of the fan-shaped insulation block 1212 can be determined by the outer diameter or outer radius and the inner diameter or inner radius of the fan-shaped insulation block 1212.

[0074] In this embodiment, the design of the thermal insulation structure is comprehensively considered through S51-S55, forming a closed-loop design process from material properties to system integration, which is more instructive and can enhance the systematicness and integrity of the design process.

[0075] In some embodiments, please refer to Figure 14 The design methodology also includes: S20: Based on the integral average of the Seebeck coefficient between the hot end temperature and the cold end temperature, the determined open-circuit voltage of the thermoelectric generator, the determined number of branches in each thermoelectric device, and the determined number of thermoelectric devices in the thermoelectric generator, obtain the number of thermocouples in a single branch of a single thermoelectric device.

[0076] S30: Obtain the number of thermocouples in a single thermoelectric device based on the number of thermocouples in a single branch of a single thermoelectric device and the determined number of branches in a single thermoelectric device.

[0077] In step S20, the number of thermoelectric elements 122 in the thermoelectric generator 10 is a known parameter, and the open-circuit voltage of the thermoelectric generator 10 is a design target value, which is also a known parameter. The number of branches in a single thermoelectric element 122 is set to two, with the two branches connected in parallel. The formula for calculating the open-circuit voltage of the thermoelectric generator 10 is: ——(15) In formula (15), This is the open-circuit voltage of the thermoelectric generator 10; The integral average of the Seebeck coefficient α of the N-type electric arm 1221b between the hot and cold end temperatures; The integral average of the Seebeck coefficient α of the P-type electric arm 1221a between the hot and cold end temperatures; denoted as , where is the temperature difference between the hot and cold ends, i.e., the temperature range between the hot and cold ends; 'n' represents the number of thermocouples 1221 in a single branch; and 'b' represents the number of thermoelectric devices 122 in the thermoelectric generator 10. This is the open-circuit voltage of a single thermocouple 1221.

[0078] According to formula (15), with all parameters except n determined, the number n of thermocouples 1221 in a single branch of a single thermoelectric device 122 can be obtained. If the obtained n is not an integer, it is rounded down and then incremented by 1. The rounding up and then incrementing by 1 can be done by rounding down, rounding up, or rounding to the nearest integer and then incrementing by 1.

[0079] For example, n is 5.

[0080] It should be noted that the temperature difference between the hot end and the cold end, i.e. the temperature range between the hot end and the cold end, can be obtained in step S10.

[0081] Since step S20 can obtain the number of thermocouples 1221 in a single branch of a single thermoelectric device 122, and step S30 requires the number of thermocouples 1221 in a single branch of a single thermoelectric device 122 to obtain the number of thermocouples 1221 in a single thermoelectric device 122, step S20 needs to be performed before step S30.

[0082] Since obtaining the thermal power of all thermoelectric devices 122 in the thermoelectric generator 10 in step S53 requires the number of thermocouples 1221 in a single thermoelectric device 122, step S30 must be performed at least before step S53.

[0083] It should be noted that the Seebeck coefficient, also known as the thermoelectric potential or thermoelectric electromotive force, is a physical quantity that describes the ability of a material to generate an electromotive force under a temperature difference. The Seebeck coefficient is essentially determined by the electronic structure properties of the material itself, such as band structure and carrier concentration. Furthermore, the dimensionality and microstructure of the material also significantly affect the Seebeck coefficient. Therefore, given that the materials and structures of the N-type electric arm 1221b and the P-type electric arm 1221a are determined, as are the hot-end and cold-end temperature ranges, the integral average of the Seebeck coefficients of the N-type electric arm 1221b and the P-type electric arm 1221a between the determined hot-end and cold-end temperatures is also determined.

[0084] In step S30, the number of thermocouples 1221 in a single thermoelectric device 122 can be obtained by multiplying the number of branches in a single thermoelectric device 122 with the number of thermocouples 1221 in a single branch of a single thermoelectric device 122.

[0085] In this embodiment, the number of thermocouples 1221 in a single thermoelectric device 122 can be obtained through steps S20 and S330, providing a basis for subsequent calculation of the cross-sectional area of ​​the N-type electric arm 1221b and the cross-sectional area of ​​the P-type electric arm 1221a.

[0086] In some embodiments, please refer to Figure 14 The design methodology also includes: S15: Based on the cross-sectional area of ​​the N-type electric arm, the cross-sectional area of ​​the P-type electric arm, the length of the N-type electric arm, the length of the P-type electric arm, the integral average thermal conductivity of the N-type electric arm material in the hot-end and cold-end temperature ranges, the integral average thermal conductivity of the P-type electric arm material in the hot-end and cold-end temperature ranges, the current flowing through a single thermocouple, the total resistance of a single thermocouple, the hot-end and cold-end temperature ranges, the Seebeck coefficient of the N-type electric arm material at the hot-end temperature, and the Seebeck coefficient of the P-type electric arm material at the hot-end temperature, obtain the thermal power flowing through a single thermocouple.

[0087] Specifically, the integral average thermal conductivity of the material of the N-type electric arm 1221b over the hot-end and cold-end temperature ranges can be determined based on the material of the N-type electric arm 1221b and the hot-end and cold-end temperature ranges. Similarly, the integral average thermal conductivity of the material of the P-type electric arm 1221a over the hot-end and cold-end temperature ranges can be determined based on the material of the P-type electric arm 1221a and the hot-end and cold-end temperature ranges. The Seebeck coefficient of the material of both the N-type and P-type electric arms 1221b at the hot-end temperature can be determined based on the materials of both types of electric arms and the hot-end temperature.

[0088] After determining the cross-sectional area of ​​the N-type electric arm 1221b, the cross-sectional area of ​​the P-type electric arm 1221a, the length of the N-type electric arm 1221b, the length of the P-type electric arm 1221a, the integral average value of the thermal conductivity of the material of the N-type electric arm 1221b in the hot-end temperature and cold-end temperature range, the integral average value of the thermal conductivity of the material of the P-type electric arm 1221a in the hot-end temperature and cold-end temperature range, the current flowing through the single thermocouple 1221, the total resistance of the single thermocouple 1221, the hot-end temperature and cold-end temperature range, the Seebeck coefficient of the material of the N-type electric arm 1221b at the hot-end temperature, and the Seebeck coefficient of the material of the P-type electric arm 1221a at the hot-end temperature, the heat power flowing through the single thermocouple 1221 can be obtained according to formula (9).

[0089] The heat power obtained in step S11 below, which flows through a single thermocouple 1221, can be used to obtain the heat power of all thermoelectric devices 122 in the thermoelectric generator 10 in step S53, thereby determining the heat flowing through the heat-insulating end cap 1211 and the fan-shaped heat-insulating block 1212 according to the principle of energy conservation.

[0090] In some embodiments, please refer to Figure 13 The methods for obtaining the length of the N-type electric arm 1221b, the length of the P-type electric arm 1221a, and the hot-end and cold-end temperature ranges include: S09: Based on the formula for calculating the maximum conversion efficiency of a single thermocouple, and using the arm length of a single thermocouple and the hot-end and cold-end temperature ranges of the thermoelectric device as variables, obtain the first efficiency distribution map of the thermoelectric device.

[0091] S10: Based on the first efficiency distribution diagram, determine the length of the N-type electric arm, the length of the P-type electric arm, and the temperature range between the hot end and the cold end.

[0092] It should be noted that since step S20 requires the hot end temperature and cold end temperature range obtained in step S02, step S02 must be performed at least before step S20.

[0093] Steps S09 and S10 are both steps to obtain parameters such as the length of the N-type electric arm 1221b, the length of the P-type electric arm 1221a, and the temperature range between the hot end and the cold end in step S11. Therefore, steps S09 and S10 need to be performed before step S11.

[0094] In step S09, based on formula (11), the arm length of a single thermocouple 1221, the hot-end temperature and cold-end temperature range of the thermoelectric device 122, the cross-sectional area ratio of the N-type arm 1221b to the P-type arm 1221a, and the maximum conversion efficiency of a single thermocouple 1221 are unknowns, while the other parameters are known parameters. The cross-sectional area ratio m of the N-type arm 1221b to the P-type arm 1221a can be set as a constant, for example, 1. The arm length of a single thermocouple 1221 and the hot-end temperature and cold-end temperature range of the thermoelectric device 122 are taken as independent variables, and the maximum conversion efficiency of a single thermocouple 1221 is taken as the dependent variable, so as to obtain the first efficiency distribution map of a single thermocouple 1221, which is also the first efficiency distribution map of the thermoelectric device 122.

[0095] Please see details. Figure 5 , Figure 5 The thermoelectric conversion efficiency of a single PN constant cross section (i.e., m=1) under different arm lengths and temperature differences is given. Figure 5 Multiple curves were plotted. On a single curve, the hot-end and cold-end temperature ranges are the same, and the arm length gradually changes with conversion efficiency. However, the hot-end and cold-end temperature ranges differ among the multiple curves. Specifically, the differences between the hot-end and cold-end temperature ranges can be due to one or both of these endpoints differing; no restriction is placed here. The curves can be formed by fitting discrete data. Figure 5 It can be seen that as the length of the electric arm increases, the conversion efficiency gradually improves, but the growth rate gradually slows down.

[0096] In step S10, the feasibility of the thermoelectric device 122 can be considered, in Figure 5 Near the inflection point of the curve, select an appropriate arm length as the design value. The lengths of the N-type arm 1221b and the P-type arm 1221a can be selected as the same or different values; no restriction is imposed here.

[0097] Since the cold end of the thermoelectric generator 10 in this application is directly connected to the outer casing 11, the cold end temperature can be approximated as the operating environment temperature of the thermoelectric generator. The cold end temperature can be determined according to the operating environment of the thermoelectric generator 10, and then the hot end temperature and cold end temperature range can be obtained based on the determined cold end temperature and the determined operating temperature difference.

[0098] In this embodiment, the length of the electric arm is determined by formula (11) and the first efficiency distribution diagram, which provides a clear method combining analysis and graphics to systematically determine the optimal length of the electric arm and avoid the blindness and uncertainty caused by relying on experience to select the electric arm length parameter in traditional methods.

[0099] In some embodiments, please refer to Figure 3 , Figure 4 and Figure 12 The thermoelectric device 122 also includes an electrode 1222. The electrode 1222 contacts the N-type electrode arm 1221b and the P-type electrode arm 1221a to form an electrical connection between the N-type electrode arm 1221b and the P-type electrode arm 1221a. The steps for obtaining the formula for calculating the maximum conversion efficiency include: S01: Based on the integral average resistivity of the N-type and P-type electric arms in the hot-end and cold-end temperature ranges, the cross-sectional area of ​​the N-type electric arm, the cross-sectional area of ​​the P-type electric arm, the length of the N-type electric arm, and the length of the P-type electric arm, obtain the resistance calculation formulas for the N-type and P-type electric arms: ——(2) ——(3) In the formula, The resistance of the N-type electric arm, The resistance of the P-type electric arm, This represents the integral average resistivity of the N-type electric arm material across the hot-end and cold-end temperature ranges. Let L be the integral average resistivity of the material of the P-type electric arm across the hot-end and cold-end temperature ranges, and L be the lengths of the P-type and N-type electric arms. Let N be the cross-sectional area of ​​the electric arm. Let be the cross-sectional area of ​​the P-type electric arm.

[0100] S02: Set the interfacial resistivity of the N-type electrode arm and the P-type electrode arm to be equal. Based on the interfacial resistivity of the N-type and P-type electrode arms and the cross-sectional area of ​​the N-type electrode arm and the P-type electrode arm, obtain the formula for calculating the interfacial contact resistance of a single electrode coupler: ——(4) In the formula, The interfacial contact resistance between a single thermocouple and its electrode is given. The interfacial resistivity between the N-type or P-type arm of a single thermocouple and the electrode.

[0101] S03: Based on the resistance calculation formulas for N-type electric arms, P-type electric arms, and the interface contact resistance calculation formula between a single thermocouple and an electrode, obtain the total resistance calculation formula for a single thermocouple: ——(5) In the formula, This represents the total resistance of a single thermocouple.

[0102] S04: Based on the integral average of the Seebeck coefficient between the hot and cold junction temperatures, the temperature range between the hot and cold junctions, and the external load resistance, obtain the formulas for calculating the open-circuit voltage and open-circuit current of a single thermocouple generated by the Seebeck effect: ——(6) ——(7) In the formula, The open-circuit voltage of a single thermocouple. This is the sum of the absolute values ​​of the integral average of the Seebeck coefficients of the materials of the N-type and P-type electric arms between the hot-end and cold-end temperatures. This refers to the hot-junction temperature of the thermoelectric device. Let I be the cold junction temperature of the thermoelectric device, and I be the open-circuit current of a single thermocouple. This is the external load resistor.

[0103] S05: Based on the external load resistance, the open-circuit voltage calculation formula for a single thermocouple, and the open-circuit current calculation formula for a single thermocouple, obtain the output power calculation formula for a single thermocouple: ——(8) In the formula, This represents the output power of a single thermocouple.

[0104] S06: Based on the Fourier heat conduction formula, the Peltier effect formula, and the Joule heating formula, obtain the formula for calculating the input heat power of a single thermocouple: ——(9) In the formula, For the input thermal power of a single thermocouple, For Fourier thermal conductivity, For Peltier thermal power, Joule heat power, This is the sum of the absolute values ​​of the Seebeck coefficients of the materials for the N-type and P-type electric arms at the hot-end temperature. Let be the integral average of the thermal conductivity of the N-type electric arm material over the hot-end and cold-end temperature ranges. This is the integral average value of the thermal conductivity of the material of the P-type electric arm in the hot-end and cold-end temperature ranges.

[0105] S07: Compare the calculation formula for the output power of a single thermocouple with the calculation formula for the input heat power of a single thermocouple, and combine formulas (2) to (9) to obtain the calculation formula for the conversion efficiency of a single thermocouple: ——(10) In the formula, This represents the conversion efficiency of a single thermocouple.

[0106] S08: Set the external load resistance to be equal to the total resistance of a single thermocouple, and obtain the formula for calculating the maximum conversion efficiency of a single thermocouple: ——(11) in, The maximum conversion efficiency of thermoelectric devices, The resistivity of the N-type electric arm, denoted as the resistivity of the P-type electric arm, and m is the ratio of the cross-sectional area of ​​the N-type electric arm to that of the P-type electric arm.

[0107] It should be noted that the formula for calculating the conversion efficiency of a single thermocouple 1221 in this application can be equivalent to the formula for calculating the conversion efficiency of thermoelectric device 122.

[0108] In step S01, according to the law of resistance, the resistance calculation formulas for the N-type electric arm 1221b and the P-type electric arm 1221a are obtained by dividing the product of resistivity and arm length by the cross-sectional area of ​​the electric arm. The resistivity can be determined by the materials of the N-type electric arm 1221b and the P-type electric arm 1221a. In this way, the parameters of arm length and cross-sectional area can be introduced to determine the relationship between these parameters and other parameters in subsequent steps.

[0109] In step S02, the interface contact resistance between the thermocouple 1221 and the electrode 1222 is calculated using the ratio of the interface contact resistivity to the contact area between the electrode arm and the electrode 1222. The contact area can be equal to the cross-sectional area of ​​the electrode arm. Since a coupler 1221 has an N-type arm 1221b and a P-type arm 1221a, the P-type arm 1221a is connected to the N-type arm 1221b of the same coupler 1221 through the electrode 1222. The P-type arm 1221a and the N-type arm 1221b are also connected to the arms of other couplers 1221 through the electrode 1222. Thus, there are two interfaces in a coupler 1221 that are in contact with the N-type arm 1221b and two interfaces that are in contact with the P-type arm 1221a. The contact resistance is equivalent to being located between the arms and forming a series with the arms. Therefore, the interface contact resistance of a coupler 1221 and the electrode 1222 is the sum of the contact resistances of each interface. The interface contact resistance of the electrode 1222 and the N-type arm 1221b and the interface contact resistance of the electrode 1222 and the P-type arm 1221a each have two identical terms. Formula (4) is the calculation formula after combining the identical terms.

[0110] In step S03, since the electric arm and electrode 1222 are essentially connected in series, the total resistance of a single thermocouple 1221 is calculated by summing. Substituting formulas (2), (3), and (4) into formula (5) yields: —(18) In step S04, formula (7) is obtained by the ratio of current to voltage to resistance, and the external load resistance of a single thermocouple 1221 is also included in the calculation formula, that is, the influence of the external load resistance on the final design is taken into account in the calculation.

[0111] In step S05, the output power of a single thermocouple 1221 is calculated by multiplying the square of the current by the external load resistance. Then, by substituting formulas (6) and (7), formula (8) can be obtained.

[0112] In step S06, according to the law of conservation of energy, the input thermal power of a single thermocouple 1221 consists of three parts: Fourier conduction heat, Peltier heat (heat absorption at the hot end), and half of the Joule heat. Among them, the Peltier heat can be calculated using the Peltier effect formula; regarding the part of the Joule heat in the input thermal power of a single thermocouple 1221, the electric arm of the thermoelectric device 122 has two end faces, a cold end and a hot end. According to experience, half of the Joule heat flows to the cold end and half flows to the hot end (or returns to the hot end). Therefore, half of the Joule heat is subtracted from the input thermal power calculation formula (9) of a single thermocouple 1221.

[0113] It is understandable that the output power is maximized when the external load resistance is equal to the internal resistance of the thermoelectric device 122, and the corresponding conversion efficiency is the maximum conversion efficiency. Therefore, the external load resistance can be set to be equal to the total resistance of a single thermocouple 1221, i.e. ,Will Substituting into formula (10), we can obtain formula (11) for calculating the maximum conversion efficiency of a single thermocouple 1221.

[0114] In steps S07 and S08, by substituting the cross-sectional area ratio m of the N-type electric arm 1221b to the P-type electric arm 1221a into formula (10), the formula is... and Transform into or At the same time, the external load resistance is set to be equal to the total resistance of a single thermocouple 1221, that is... Ultimately, the cross-sectional area in the formula can be canceled out, thus obtaining formula (11), which simplifies the calculation formula and is beneficial for subsequent research on the relationship between the design parameters of the electric couple 1221 based on formula (11).

[0115] In this embodiment, formula (10) is obtained by formulas (2) to (9) and further simplified to formula (11). Based on the conservation of energy, the thermoelectric coupling relationship between Seebeck effect, Peltier effect and Joule heating effect is considered. A mathematical model is established for the subsequent study of the relationship between the design parameters of thermocouple 1221. This can significantly reduce the design deviation caused by ignoring key physical effects and make the design result of thermoelectric device 122 more in line with the actual working state. At the same time, the method of this embodiment is based on the derivation of basic principles and is applicable to the design of the transducer module 12 of thermoelectric generator 10 with different thermoelectric materials and different structural forms. Designers can flexibly apply this method to perform customized optimization design according to specific performance indicators (such as target output voltage and power), working environment (cold end temperature) and process constraints.

[0116] In some embodiments, please refer to Figure 13 Methods for obtaining the total resistance of a single thermocouple 1221 include: S11: Obtain the total resistance of the thermoelectric generator based on the target output power and target open-circuit voltage of the thermoelectric generator.

[0117] S12: Based on the total resistance of the thermoelectric generator, the determined number of thermoelectric devices, and the number of thermocouples for each thermoelectric device, obtain the total resistance of a single thermocouple.

[0118] In step S11, the formula for calculating the total resistance of the thermoelectric generator 10 is: —(16) In formula (16), The target open-circuit voltage of the thermoelectric generator 10 is given by [value], and [value] is a known parameter. Let be the target output power of the thermoelectric generator 10, and be the known parameters. The total resistance of thermoelectric generator 10 is given.

[0119] When there are two branches connected in parallel, the relationship between the total resistance of the thermoelectric generator 10, the number of thermoelectric devices 122, the number of thermocouples 1221 in each thermoelectric device 122, and the total resistance of the thermoelectric generator 10 can be expressed as follows: ——(17) In formula (17), n is the number of thermocouples 1221 in a single branch, which can be obtained in step S20; b is the number of thermoelectric devices 122 in the thermoelectric generator 10, which is a known parameter. The total resistance of thermoelectric generator 10 The total resistance of a single thermocouple 1221.

[0120] The total resistance of the entire thermoelectric generator 10 can be obtained from formula (16) and the total resistance of a single thermoelectric generator 10. Then, based on formula (17) and the total resistance of the thermoelectric generator 10, the total resistance of a single thermoelectric generator 1221 can be obtained, thus providing a basis for subsequent calculation of the cross-sectional area of ​​the N-type electric arm 1221b and the cross-sectional area of ​​the P-type electric arm 1221a.

[0121] In some embodiments, please refer to Figure 13 The methods for obtaining the cross-sectional area of ​​the N-type electric arm 1221b and the cross-sectional area of ​​the P-type electric arm 1221a include: S13: Based on the formula for calculating the maximum conversion efficiency of a single thermocouple, and taking into account the cold junction temperature of the thermoelectric device, the determined length of the N-type arm, the determined length of the P-type arm, and the determined hot junction temperature and cold junction temperature range, the cross-sectional area ratio of the N-type arm to the P-type arm of the thermoelectric device is used as a variable to obtain a second efficiency distribution map of the conversion efficiency of the thermoelectric device as a function of the cross-sectional area ratio of the N-type arm to the P-type arm. Based on the second efficiency distribution map, the cross-sectional area ratio of the N-type arm to the P-type arm is obtained.

[0122] S14: Combining formulas (2), (3), (4), and (5), and based on the total resistance of a single thermocouple, the average resistivity integral of the N-type and P-type thermocouples in the hot and cold end temperature ranges, the interfacial resistivity between the P-type thermocouple and the electrode, the interfacial resistivity between the N-type thermocouple and the electrode, and the ratio of the cross-sectional areas of the N-type and P-type thermocouples, the cross-sectional area of ​​the N-type thermocouple and the cross-sectional area of ​​the P-type thermocouple are obtained.

[0123] In step S13, the cold junction temperature of thermoelectric device 122, the length of N-type electric arm 1221b, the length of P-type electric arm 1221a, and the temperature range between the hot and cold junctions can be determined in step S10. Substituting the determined parameters into formula (11), only the cross-sectional area ratio m of N-type electric arm 1221b to P-type electric arm 1221a and the maximum conversion efficiency of a single thermocouple 1221 remain unknowns. Therefore, the cross-sectional area ratio m of N-type electric arm 1221b to P-type electric arm 1221a of thermoelectric device 1222 can be used as a variable to obtain a second efficiency distribution diagram of the conversion efficiency of thermoelectric device 122 as a function of the cross-sectional area ratio m of N-type electric arm 1221b to P-type electric arm 1221a. The second efficiency distribution diagram is shown below. Figure 6 As shown.

[0124] Based on the second efficiency distribution diagram, the cross-sectional area ratio of the N-type electric arm 1221b to the P-type electric arm 1221a is obtained. Specifically, the cross-sectional area ratio m with the highest or closest conversion efficiency is selected by combining device process and balance.

[0125] In step S14, formula (18) can be transformed into the following formula: —(19) In formula (19), s is the reciprocal of m, which is the ratio of the cross-sectional area of ​​the P-type electric arm 1221a to that of the N-type electric arm 1221b.

[0126] Given that the average resistivity integral of N-type electric arm 1221b and P-type electric arm 1221a in the hot and cold end temperature ranges, the interface resistivity of P-type electric arm 1221a and electrode 1222, the interface resistivity of N-type electric arm 1221b and electrode 1222, the length of N-type electric arm 1221b, the length of P-type electric arm 1221a, etc., are all known, the total resistance of a single thermocouple 1221 is known, and the ratio s of the cross-sectional areas of P-type electric arm 1221a and N-type electric arm 1221b is known, the cross-sectional area of ​​N-type electric arm 1221b can be obtained according to formula (19), and then the cross-sectional area of ​​P-type electric arm 1221a can be obtained. Thus, the heat power flowing through a single thermocouple 1221 can be calculated according to formula (9).

[0127] For example, in one embodiment, please refer to Figure 11 , Figure 14 and Figure 15 The design methods for the energy conversion module of a thermoelectric generator include: S01: Based on the integral average resistivity of the N-type and P-type electric arms in the hot-end and cold-end temperature ranges, the cross-sectional area of ​​the N-type electric arm, the cross-sectional area of ​​the P-type electric arm, the length of the N-type electric arm, and the length of the P-type electric arm, obtain the resistance calculation formulas for the N-type and P-type electric arms: ——(2) ——(3) In equations (2) and (3), The resistance of the N-type electric arm, The resistance of the P-type electric arm, This represents the integral average resistivity of the N-type electric arm material across the hot-end and cold-end temperature ranges. Let L be the integral average resistivity of the material of the P-type electric arm across the hot-end and cold-end temperature ranges, and L be the lengths of the P-type and N-type electric arms. Let N be the cross-sectional area of ​​the electric arm. Let be the cross-sectional area of ​​the P-type electric arm.

[0128] S02: Set the interfacial resistivity of the N-type electrode arm and the P-type electrode arm to be equal. Based on the interfacial resistivity of the N-type and P-type electrode arms and the cross-sectional area of ​​the N-type electrode arm and the P-type electrode arm, obtain the formula for calculating the interfacial contact resistance of a single electrode coupler: ——(4) In formula (4), The interfacial contact resistance between a single thermocouple and its electrode is given. The interfacial resistivity between the N-type or P-type arm of a single thermocouple and the electrode.

[0129] S03: Based on the resistance calculation formulas for N-type electric arms, P-type electric arms, and the interface contact resistance calculation formula between a single thermocouple and an electrode, obtain the total resistance calculation formula for a single thermocouple: ——(5) In formula (5), This represents the total resistance of a single thermocouple.

[0130] S04: Based on the integral average of the Seebeck coefficient between the hot and cold junction temperatures, the temperature range between the hot and cold junctions, and the external load resistance, obtain the formulas for calculating the open-circuit voltage and open-circuit current of a single thermocouple generated by the Seebeck effect: ——(6) ——(7) In equations (6) and (7), The open-circuit voltage of a single thermocouple. This is the sum of the absolute values ​​of the integral average of the Seebeck coefficients of the materials of the N-type and P-type electric arms between the hot-end and cold-end temperatures. This refers to the hot-junction temperature of the thermoelectric device. Let I be the cold junction temperature of the thermoelectric device, and I be the open-circuit current of a single thermocouple. This is the external load resistor.

[0131] S05: Based on the external load resistance, the open-circuit voltage calculation formula for a single thermocouple, and the open-circuit current calculation formula for a single thermocouple, obtain the output power calculation formula for a single thermocouple: ——(8) In equation (8), This represents the output power of a single thermocouple.

[0132] S06: Based on the Fourier heat conduction formula, the Peltier effect formula, and the Joule heating formula, obtain the formula for calculating the input heat power of a single thermocouple: ——(9) In the formula, For the input thermal power of a single thermocouple, For Fourier thermal conductivity, For Peltier thermal power, Joule heat power, This is the sum of the absolute values ​​of the Seebeck coefficients of the materials for the N-type and P-type electric arms at the hot-end temperature. Let be the integral average of the thermal conductivity of the N-type electric arm material over the hot-end and cold-end temperature ranges. This is the integral average value of the thermal conductivity of the material of the P-type electric arm in the hot-end and cold-end temperature ranges.

[0133] S07: Compare the calculation formula for the output power of a single thermocouple with the calculation formula for the input heat power of a single thermocouple, and combine formulas (2) to (9) to obtain the calculation formula for the conversion efficiency of a single thermocouple: ——(10) In formula (10), This represents the conversion efficiency of a single thermocouple.

[0134] S08: Set the external load resistance to be equal to the total resistance of a single thermocouple, and obtain the formula for calculating the maximum conversion efficiency of a single thermocouple: ——(11) In formula (11), The maximum conversion efficiency of thermoelectric devices, The resistivity of the N-type electric arm, denoted as the resistivity of the P-type electric arm, and m is the ratio of the cross-sectional area of ​​the N-type electric arm to that of the P-type electric arm.

[0135] S09: Based on the formula for calculating the maximum conversion efficiency of a single thermocouple, and using the arm length of a single thermocouple and the hot-end and cold-end temperature ranges of the thermoelectric device as variables, obtain the first efficiency distribution map of the thermoelectric device.

[0136] S10: Based on the first efficiency distribution diagram, determine the length of the N-type electric arm, the length of the P-type electric arm, and the temperature range between the hot end and the cold end.

[0137] S11: Obtain the total resistance of the thermoelectric generator based on the target output power and target open-circuit voltage of the thermoelectric generator.

[0138] S12: Based on the total resistance of the thermoelectric generator, the determined number of thermoelectric devices, and the number of thermocouples for each thermoelectric device, obtain the total resistance of a single thermocouple.

[0139] S13: Based on the formula for calculating the maximum conversion efficiency of a single thermocouple, and taking into account the cold junction temperature of the thermoelectric device, the determined length of the N-type arm, the determined length of the P-type arm, and the determined hot junction temperature and cold junction temperature range, the cross-sectional area ratio of the N-type arm to the P-type arm of the thermoelectric device is used as a variable to obtain a second efficiency distribution map of the conversion efficiency of the thermoelectric device as a function of the cross-sectional area ratio of the N-type arm to the P-type arm. Based on the second efficiency distribution map, the cross-sectional area ratio of the N-type arm to the P-type arm is obtained.

[0140] S14: Combining formulas (2), (3), (4), and (5), and based on the total resistance of a single thermocouple, the average resistivity integral of the N-type and P-type thermocouples in the hot and cold end temperature ranges, the interfacial resistivity between the P-type thermocouple and the electrode, the interfacial resistivity between the N-type thermocouple and the electrode, and the ratio of the cross-sectional areas of the N-type and P-type thermocouples, the cross-sectional area of ​​the N-type thermocouple and the cross-sectional area of ​​the P-type thermocouple are obtained.

[0141] S15: Based on the cross-sectional area of ​​the N-type electric arm, the cross-sectional area of ​​the P-type electric arm, the length of the N-type electric arm, the length of the P-type electric arm, the integral average thermal conductivity of the N-type electric arm material in the hot-end and cold-end temperature ranges, the integral average thermal conductivity of the P-type electric arm material in the hot-end and cold-end temperature ranges, the current flowing through a single thermocouple, the total resistance of a single thermocouple, the hot-end and cold-end temperature ranges, the Seebeck coefficient of the N-type electric arm material at the hot-end temperature, and the Seebeck coefficient of the P-type electric arm material at the hot-end temperature, obtain the thermal power flowing through a single thermocouple.

[0142] S20: Based on the integral average of the Seebeck coefficient between the hot end temperature and the cold end temperature, the determined open-circuit voltage of the thermoelectric generator, the determined number of branches in each thermoelectric device, and the determined number of thermoelectric devices in the thermoelectric generator, obtain the number of thermocouples in a single branch of a single thermoelectric device.

[0143] S30: Obtain the number of thermocouples in a single thermoelectric device based on the number of thermocouples in a single branch of a single thermoelectric device and the determined number of branches in a single thermoelectric device.

[0144] S41: Obtain the target total thermal power of the thermoelectric generator based on the ratio of the target output power of the thermoelectric generator to the target conversion efficiency of the thermoelectric generator.

[0145] S42: Based on the Fourier heat conduction formula, the integral average of the thermal conductivity of the insulation end cap material in the hot end temperature and cold end temperature range, and the area of ​​the insulation end cap, obtain the formula for calculating the heat power flowing through the insulation end cap, and obtain the heat loss distribution diagram of the insulation end cap based on the formula for calculating the heat power flowing through the insulation end cap.

[0146] S51: Determine the thickness of the insulation end cap based on the heat loss distribution diagram of the insulation end cap.

[0147] S52: Determine the diameter of the insulation end cap based on the outer diameter of the heat distributor, and obtain the heat power flowing through the insulation end cap according to the determined thickness of the insulation end cap and the heat power flowing through the insulation end cap.

[0148] S53: Obtain the thermal power of all thermoelectric devices in the thermoelectric generator based on the thermal power flowing through a single thermocouple, the number of thermocouples in a single thermoelectric device, and the number of thermoelectric devices in the thermoelectric generator.

[0149] S54: Based on the principle of energy conservation, and combining the target total heat power of the thermoelectric generator, the heat power of all thermoelectric devices, and the heat power flowing through the insulation end cover, obtain the heat power flowing through the fan-shaped insulation block.

[0150] S55: Based on the formula for calculating the heat power flowing through the sector-shaped insulation block, the thickness of the sector-shaped insulation block is obtained according to the heat power flowing through the sector-shaped insulation block and the determined inner arc length of the sector-shaped insulation block.

[0151] The optimized design method of the thermoelectric generator 10 and the transducer module 12 in this embodiment has the following significant advantages: 1. Improved design accuracy and reliability: By comprehensively considering the thermoelectric coupling relationship between the Seebeck effect, Peltier effect and Joule heating effect, and establishing a mathematical model based on the strict principle of energy conservation, the design deviation caused by neglecting key physical effects is significantly reduced, making the design results more in line with the actual working conditions.

[0152] 2. Optimization design of key structural parameters was achieved: A clear analytical and graphical method was provided to systematically determine the optimal length (L) of the thermoelectric arm, the optimal cross-sectional area ratio (m) of the P-type electric arm 1221a and the N-type electric arm 1221b, the optimal cross-sectional area of ​​the P-type electric arm 1221a and the N-type electric arm 1221b, and the reasonable thickness of the insulation component 121 (end cap and sector block), avoiding the blindness and uncertainty caused by relying on experience to select parameters in traditional methods.

[0153] 3. Improved thermoelectric conversion efficiency and device performance: By optimizing the size and proportion of the electric arm, the thermocouple 1221 is made closer to the point of maximum conversion efficiency under its operating temperature difference, thereby obtaining higher power output under given heat source conditions, or reducing the demand for heat source (radioactive isotope) when meeting the same power requirements, which helps to reduce system cost and extend service life.

[0154] 4. Enhanced the systematicness and integrity of the design process: The method derives the macroscopic performance (total voltage, total power, heat loss) of the entire transducer module 12 from the microscopic parameters (material properties, geometric dimensions) of a single thermocouple 1221 pair, and takes into account the design of the insulation structure in a coordinated manner, forming a closed-loop design process from material properties to system integration, which is more instructive.

[0155] 5. Excellent applicability and flexibility: The method is derived based on fundamental principles and is applicable to the design of thermoelectric generator 10 and converter module 12 using different thermoelectric materials and structural forms. Designers can flexibly apply this method for customized optimization design according to specific performance indicators (such as target output voltage and power), operating environment (cold end temperature) and process constraints.

[0156] Thus, this application provides an optimized design method for the energy conversion module 12 of the thermoelectric generator 10, which is theoretically rigorous, has clear steps, and yields reliable results. This method is of great value for improving the performance of the thermoelectric generator 10, reducing its manufacturing cost, and promoting its application in special environments.

[0157] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, and improvements made within the spirit and scope of this application are included within the scope of protection of this application.

Claims

1. A design method for a thermoelectric generator's transducer module, the transducer module comprising an insulation component and multiple thermoelectric devices, characterized in that, The design method includes: Based on the target conversion efficiency of the thermoelectric generator, the target output power of the thermoelectric generator, and the thermal power of all the thermoelectric devices, obtain the heat loss distribution diagram of the thickness of the insulation component as a function of heat loss. The thickness of the insulation component is determined based on the heat loss distribution diagram.

2. The design method according to claim 1, characterized in that, The insulation component includes an insulation end cap, and the energy conversion module further includes a heat distributor. The hot end of the thermoelectric device is disposed on the outer surface of the heat distributor, and the cold end of the thermoelectric device is in contact with the outer shell of the thermoelectric generator. The insulation end cap is disposed on the end face of the heat distributor. The step of obtaining a heat loss distribution diagram of the thickness of the insulation component as a function of heat loss based on the target conversion efficiency of the thermoelectric generator, the target output power of the thermoelectric generator, and the thermal power of all the thermoelectric devices includes: The target total thermal power of the thermoelectric generator is obtained by the ratio of the target output power of the thermoelectric generator to the target conversion efficiency of the thermoelectric generator. Based on the Fourier heat conduction formula, the integral average of the thermal conductivity of the insulation end cap material in the hot and cold end temperature ranges, and the area of ​​the insulation end cap, a formula for calculating the heat power flowing through the insulation end cap is obtained. Based on the formula for calculating the heat power flowing through the insulation end cap, a heat loss distribution diagram of the insulation end cap is obtained.

3. The design method according to claim 2, characterized in that, The insulation component further includes a fan-shaped insulation block. The thermoelectric device includes multiple thermocouples, each thermocouple including a P-type arm and an N-type arm. The inner sidewall of the fan-shaped insulation block is disposed on the outer periphery of the heat distributor, and the fan-shaped insulation block is located between two adjacent thermoelectric devices. The step of determining the thickness of the insulation component according to the heat loss distribution diagram includes: The thickness of the insulation end cap is determined based on the heat loss distribution diagram of the insulation end cap; The diameter of the insulation end cap is determined based on the outer diameter of the heat distributor. The heat power flowing through the insulation end cap is obtained based on the determined thickness of the insulation end cap and the heat power calculation formula. The thermal power of all thermoelectric devices in the thermoelectric generator is obtained based on the thermal power flowing through a single thermocouple, the number of thermocouples in a single thermoelectric device, and the number of thermoelectric devices in the thermoelectric generator. Based on the principle of energy conservation, and combining the target total thermal power of the thermoelectric generator, the thermal power of all the thermoelectric devices, and the thermal power flowing through the insulation end cap, the thermal power flowing through the fan-shaped insulation block is obtained. Based on the formula for calculating the heat power flowing through the sector-shaped insulation block, the thickness of the sector-shaped insulation block is obtained according to the heat power flowing through the sector-shaped insulation block and the determined inner arc length of the sector-shaped insulation block.

4. The design method according to claim 3, characterized in that, The formula for calculating the heat power flowing through the fan-shaped insulation block is: ——(1) in, The thermal power of the fan-shaped insulation block, This refers to the hot-junction temperature of the thermoelectric device. The cold junction temperature of the thermoelectric device. It is the integral average value of the thermal conductivity of the insulation material in the temperature range between the hot and cold ends, where t is the inner arc length of the sector-shaped insulation block. The outer radius of the sector-shaped insulation block. Let be the inner radius of the sector-shaped insulation block.

5. The design method according to claim 3, characterized in that, The design method further includes: The number of thermocouples in a single branch of a single thermoelectric device is obtained based on the integral average of the Seebeck coefficient between the hot end temperature and the cold end temperature, the determined open-circuit voltage of the thermoelectric generator, the determined number of branches in each thermoelectric device, and the determined number of thermoelectric devices in the thermoelectric generator. The number of thermocouples in a single thermoelectric device is obtained based on the number of thermocouples in a single branch of a single thermoelectric device and the determined number of branches in a single thermoelectric device.

6. The design method according to claim 3, characterized in that, The design method further includes: The thermal power flowing through a single thermocouple is obtained based on the cross-sectional area of ​​the N-type thermocouple, the cross-sectional area of ​​the P-type thermocouple, the length of the N-type thermocouple, the length of the P-type thermocouple, the integral average thermal conductivity of the material of the N-type thermocouple in the hot-end and cold-end temperature ranges, the integral average thermal conductivity of the material of the P-type thermocouple in the hot-end and cold-end temperature ranges, the current flowing through a single thermocouple, the total resistance of a single thermocouple, the hot-end and cold-end temperature ranges, the Seebeck coefficient of the material of the N-type thermocouple at the hot-end temperature, and the Seebeck coefficient of the material of the P-type thermocouple at the hot-end temperature.

7. The design method according to claim 6, characterized in that, The method for obtaining the length of the N-type electric arm, the length of the P-type electric arm, and the hot-end temperature and cold-end temperature range includes: Based on the formula for calculating the maximum conversion efficiency of a single thermocouple, and using the arm length of the single thermocouple and the hot-end and cold-end temperature ranges of the thermoelectric device as variables, a first efficiency distribution map of the thermoelectric device is obtained. Based on the first efficiency distribution diagram, the length of the N-type electric arm, the length of the P-type electric arm, and the hot-end temperature and cold-end temperature range are determined.

8. The design method according to claim 7, characterized in that, The thermoelectric device further includes an electrode that contacts the N-type electric arm and the P-type electric arm to form an electrical connection between the N-type and P-type electric arms. The step of obtaining the formula for calculating the maximum conversion efficiency includes: Based on the integral average resistivity of the N-type and P-type electric arms in the hot-end and cold-end temperature ranges, the cross-sectional area of ​​the N-type electric arm, the cross-sectional area of ​​the P-type electric arm, the length of the N-type electric arm, and the length of the P-type electric arm, the resistance calculation formulas for the N-type and P-type electric arms are obtained: ——(2) ——(3) In the formula, The resistance of the N-type electric arm, The resistance of the P-type electric arm, The resistivity of the material of the N-type electric arm is the integral average value of the resistivity in the hot-end and cold-end temperature ranges. Let L be the integral average resistivity of the material of the P-type electric arm across the hot-end and cold-end temperature ranges, and L be the length of the P-type electric arm and the length of the N-type electric arm. The cross-sectional area of ​​the N-type electric arm is... The cross-sectional area of ​​the P-type electric arm; The interfacial resistivity of the N-type electrode arm and the electrode plate and the interfacial resistivity of the P-type electrode arm and the electrode plate are set to be equal. Based on the interfacial resistivity of the N-type electrode arm and the P-type electrode arm and the electrode plate, the cross-sectional area of ​​the N-type electrode arm and the cross-sectional area of ​​the P-type electrode arm, the formula for calculating the interfacial contact resistance of a single electrode coupler is obtained: ——(4) In the formula, The interfacial contact resistance between a single thermocouple and the electrode plate. The interface resistivity between the N-type arm or P-type arm of a single thermocouple and the electrode; Based on the resistance calculation formulas for the N-type electric arm, the P-type electric arm, and the interface contact resistance calculation formula between a single thermocouple and the electrode, the total resistance calculation formula for a single thermocouple is obtained: ——(5) In the formula, The total resistance of a single thermocouple; Based on the integral average of the Seebeck coefficient between the hot and cold junction temperatures, the temperature range between the hot and cold junctions, and the external load resistance, the formulas for calculating the open-circuit voltage and open-circuit current of a single thermocouple generated by the Seebeck effect are obtained: ——(6) ——(7) In the formula, The open-circuit voltage of a single said thermocouple, It is the sum of the absolute values ​​of the integral average of the Seebeck coefficients of the materials of the N-type electric arm and the P-type electric arm between the hot-end temperature and the cold-end temperature. The hot-junction temperature of the thermoelectric device. I represents the cold junction temperature of the thermoelectric device, and I represents the open-circuit current of a single thermocouple. The external load resistor; Based on the determined external load resistance, the formula for calculating the open-circuit voltage of a single thermocouple, and the formula for calculating the open-circuit current of a single thermocouple, the formula for calculating the output power of a single thermocouple is obtained: ——(8) In the formula, The output power of the single thermocouple; Based on the Fourier heat conduction formula, the Peltier effect formula, and the Joule heating formula, the formula for calculating the input heat power of a single thermocouple is obtained: ——(9) In the formula, The input thermal power of a single said thermocouple, For Fourier heat conduction power, For Peltier thermal power, Joule heat power, The sum of the absolute values ​​of the Seebeck coefficients of the materials of the N-type electric arm and the P-type electric arm at the hot-end temperature. The integral average value of the thermal conductivity of the material of the N-type electric arm in the hot-end and cold-end temperature ranges is given. The integral average value of the thermal conductivity of the material of the P-type electric arm in the hot-end temperature and cold-end temperature range; The calculation formula for the output power of a single thermocouple is compared with the calculation formula for the input heat power of a single thermocouple, and combined with formulas (2) to (9), the calculation formula for the conversion efficiency of a single thermocouple is obtained: ——(10) In the formula, The conversion efficiency of a single said couple; The external load resistor is set to be equal to the total resistance of a single thermocouple, and the formula for calculating the maximum conversion efficiency of a single thermocouple is obtained: ——(11) in, This represents the maximum conversion efficiency of the thermoelectric device. The resistivity of the N-type electric arm is... denoted as the resistivity of the P-type electric arm, and m is the ratio of the cross-sectional area of ​​the N-type electric arm to that of the P-type electric arm.

9. The design method according to claim 8, characterized in that, A method for obtaining the total resistance of a single said thermocouple includes: The total resistance of the thermoelectric generator is obtained based on the target output power and target open-circuit voltage of the thermoelectric generator. The total resistance of a single thermocouple is obtained based on the total resistance of the thermoelectric generator, the determined number of thermoelectric devices, and the number of thermocouples in each thermoelectric device.

10. The design method according to claim 9, characterized in that, The method for obtaining the cross-sectional area of ​​the N-type electric arm and the cross-sectional area of ​​the P-type electric arm includes: Based on the formula for calculating the maximum conversion efficiency of a single thermocouple, and taking into account the cold junction temperature of the thermoelectric device, the determined length of the N-type arm, the determined length of the P-type arm, and the determined hot junction temperature and cold junction temperature range, a second efficiency distribution map is obtained, using the cross-sectional area ratio of the N-type arm to the P-type arm of the thermoelectric device as a variable. Based on the second efficiency distribution map, the cross-sectional area ratio value of the N-type arm to the P-type arm is obtained. Combining formulas (2), (3), (4), and (5), and based on the total resistance of a single thermocouple, the average resistivity of the N-type and P-type thermocouples in the hot-end and cold-end temperature ranges, the interfacial resistivity of the P-type thermocouple and the electrode, the interfacial resistivity of the N-type thermocouple and the electrode, and the ratio of the cross-sectional areas of the N-type and P-type thermocouples, the cross-sectional area of ​​the N-type thermocouple and the cross-sectional area of ​​the P-type thermocouple are obtained.

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