CN102412762A - Cascade-type thermoelectric generator - Google Patents

Abstract

The present invention relates to a cascaded thermoelectric generator, comprising a heat source that generates heat, a thermoelectric power generation unit that converts heat into electrical energy, and a casing, wherein the thermoelectric power generation unit includes sequentially radial At least two thermoelectric power generation systems cascaded outwardly, the at least two thermoelectric power generation systems in cascade transfer heat step by step, and the thermoelectric power generation systems of each stage use the heat received by them to perform thermoelectric conversion.

Description

Cascade Thermoelectric Generator

technical field

The invention relates to the technical field of thermoelectric conversion, in particular to a cascaded thermoelectric generator.

Background technique

Thermoelectric power generation technology is a technology that uses the Seebeck effect of thermoelectric materials to directly convert thermal energy into electrical energy. It has the characteristics of small size, high reliability, and long life of thermoelectric devices. According to the principle of thermoelectric conversion, All heat sources including solar energy can be utilized, and high-power electric power can be obtained with a small area. Therefore, it plays an important role in technical fields such as space science, military equipment, and waste heat power generation, and has attracted more and more attention.

Thermoelectric generators generally have a cylindrical structure and adopt a single-stage structure, that is, only one thermoelectric material or thermoelectric device is used. Its structure is that the heat source is located in the center of the cylindrical structure, the thermoelectric devices are distributed outside the heat source in a radial shape, and the outermost layer of the thermoelectric generator is a heat dissipation structure, wherein the thermoelectric devices convert heat energy from the heat source into electrical energy. A thermoelectric device is an element that directly converts thermal energy into electrical energy, and is usually composed of a homogeneous thermoelectric material; a thermoelectric material is a functional material that uses the movement of carriers inside a solid to achieve direct mutual conversion of thermal energy and electrical energy, and the temperature difference between its two ends can be generate voltage.

Since the performance figure of merit Z of thermoelectric materials (Z=α ² σ/κ, where α is the Seebeck coefficient; σ is the electrical conductivity; κ is the thermal conductivity) is closely related to the temperature of the material, the optimal working temperature of each thermoelectric material The interval is only within a specific small range, and the performance of thermoelectric materials will drop sharply after exceeding the optimum operating temperature interval. If the actual operating temperature range of thermoelectric materials (thermoelectric devices) is relatively large (beyond the operating temperature range of a single thermoelectric material), it is difficult for a thermoelectric generator composed of a single homogeneous thermoelectric material to obtain the maximum energy conversion efficiency, so along the temperature The gradient direction selects thermoelectric materials (thermoelectric devices) with different optimal operating temperatures, and makes them work in their optimal operating temperature range, which can effectively improve the efficiency of thermoelectric power generation.

The efficiency of thermoelectric power generation can be improved by combining multiple segments of thermoelectric materials or cascading thermoelectric devices. Kajikawa (The 20 ^th International Conference on Thermoelectrics, Beijing, 2001:49-56), El-Genk (Energ. Convers. Manage, 2005(46):1083-1105), etc. reported that the method of cascading and multi-stage compounding can improve Experimental results of material thermoelectric power generation efficiency. In addition, Japanese Patent Laid-Open 2005-19910, Japanese Patent Laid-Open 2006-245224, WO96/15412, US6722140B2, US6662570B2, US6505468B2 and other patents also disclose technical solutions of various multi-stage composite thermoelectric materials and cascaded thermoelectric devices. For example, Japanese Patent Laid-Open No. 2005-19910 discloses that another 1 to 2 thermoelectric material layers with thermal expansion rates between the two materials are inserted between different thermoelectric materials with different thermal expansion rates, thereby relieving the effect of thermal stress. technology. Japanese Patent Laid-Open No. 2006-245224 discloses that on the insulating substrate located at the upper end of the device for thermoelectric conversion in the low temperature segment, the device for thermoelectric conversion in the high temperature segment and the clamping part are sequentially loaded, thereby reducing the effect on the device for thermoelectric conversion. A technology that reduces heat loss while maintaining thermal stress.

However, although the multi-stage composite of thermoelectric materials can improve the overall power generation efficiency of the composite material, due to the different materials of each segment, different materials have mismatched expansion coefficients at the connection interface, which is easy to deform and crack at high temperatures, and due to the different The electrical conductivity and thermal conductivity of thermoelectric materials are not completely consistent, and additional contact resistance and contact thermal resistance will be added at the connection interface. In addition, inter-diffusion between elements and chemical reactions between elements will occur at the interface or near the interface under long-term high-temperature action, which will affect the thermal stability of the material. Secondly, the optimal geometric size requirements of each segmented material are relatively different. When it is large, it is difficult to obtain the expected thermoelectric power generation efficiency.

For cascaded thermoelectric devices, there is generally an insulating layer between the stages, that is, an inter-stage series structure. The insulating layer between the stages is required to have high thermal conductivity and high electrical insulation, and to have a sufficiently high connection strength. Due to the large actual operating temperature range of the cascaded thermoelectric device, the interstage insulating layer is prone to cracking when it works under high temperature and large temperature difference for a long time, causing excessive contact resistance and contact thermal resistance inside the cascaded thermoelectric device, which leads to poor performance of the thermoelectric device. Attenuation or even failure.

Contents of the invention

The technical problem to be solved by the present invention includes providing a cascaded thermoelectric generator, which can improve the overall efficiency of the generator without affecting the reliability of the generator.

In order to solve the above technical problems, the present invention provides a cascaded thermoelectric generator, which includes a heat source that generates heat, a thermoelectric power generation unit that converts heat into electrical energy, and a casing, wherein the thermoelectric power generation unit includes At least two thermoelectric power generation systems cascaded radially outward in the direction of heat transfer, the at least two thermoelectric power generation systems in cascade transfer heat step by step, and the thermoelectric power generation systems at each level use the heat received Thermoelectric conversion.

With the present invention, through the cascading of multiple thermoelectric power generation systems, the heat is transferred from the heat source to the shell through the thermoelectric power generation systems of each temperature section, and a temperature difference is generated when the heat passes through the thermoelectric power generation systems of various levels, and then electric energy is generated, and at least two thermoelectric power generation systems The systems are relatively independent, so that the thermoelectric power generation system can perform thermoelectric conversion relatively independently, even if one system fails, other systems can still work normally. Therefore, on the premise of ensuring the reliability of the thermoelectric generator, the working temperature range of the thermoelectric generator is expanded, and the overall efficiency of the thermoelectric generator is improved.

In the present invention, it is also possible that the thermoelectric power generation systems at all levels respectively include a heat collecting member, a thermoelectric member and a heat dissipation member arranged radially outward along the heat transfer direction, and the high temperature side of the thermoelectric member is connected to the heat collecting member And the low-temperature side of the thermoelectric component is connected to the heat dissipation component, and the thermoelectric component receives heat from the heat collection component to perform thermoelectric conversion and further transfers heat to the heat dissipation component.

Adopting the invention is beneficial to realize the thermoelectric conversion of thermoelectric power generation systems at various levels.

In the present invention, it is also possible that among the adjacently arranged two-stage thermoelectric power generation systems, the heat radiating member of the upper thermoelectric power generation system located at the upper position in the heat transfer direction is the heat collector of the lower thermoelectric generation system located at the lower position in the heat transfer direction. member.

With the present invention, since the two-stage thermoelectric power generation system shares the heat dissipation component and the heat collection component, the continuity of heat transfer is ensured, and when one system is in failure state, other systems can still work normally.

In the present invention, it is also possible that the thermoelectric power generation systems at all levels select thermoelectric components with different working temperatures according to the temperature at the heat collecting components.

By adopting the present invention, the thermoelectric components of the thermoelectric power generation systems at all levels are respectively at their respective optimal working temperatures, so that the maximum energy conversion efficiency can be obtained.

In the present invention, it is also possible that the heat-collecting components and heat-dissipating components of the thermoelectric power generation system at each level are cylindrical structures arranged coaxially, and the thermoelectric components are distributed radially between the heat-collecting components and the heat-dissipating components. thermoelectric devices.

By adopting the invention, the thermoelectric conversion efficiency of the whole thermoelectric generator can be improved.

In the present invention, it is also possible that the heat dissipation component of the thermoelectric power generation system located at the lowest position in the heat transfer direction is the casing of the cascaded thermoelectric generator.

By adopting the invention, the casing can be used as the heat dissipation structure of the whole thermoelectric generator system, and the heat is transmitted from the heat source to the casing through the thermoelectric generation systems of various temperature sections, and then dissipated from the casing.

In the present invention, it is also possible to further include a press connected between the low-temperature side of the thermoelectric components of the thermoelectric generation system located at the lowest position in the heat transfer direction and the housing to compress each component in each thermoelectric generation system. Tighten the fixture.

By adopting the present invention, each component in each thermoelectric power generation system can be compressed by the pressing and fixing device, so as to maintain good contact between each thermoelectric component, heat collecting component, and heat dissipation component to ensure good heat transfer.

In the present invention, it is also possible to further include a support member connected to the pressing and fixing device and closely attached to the inner side of the casing.

By adopting the present invention, the setting of the support component can not only provide fixed support for the pressing and fixing device, but also facilitate heat transfer.

In the present invention, it is also possible that the pressing and fixing device presses each component in each thermoelectric power generation system by means of screw pressing or spring pressing.

By adopting the present invention, the pressing and fixing device can reliably and stably press each component in each thermoelectric power generation system to ensure good heat transfer.

In the present invention, it is also possible that a plurality of radially distributed cooling fins are formed on the outer surface of the housing.

By adopting the invention, the heat inside the generator can be effectively transferred to the outside, the temperature difference in the direction of heat transfer can be widened, and the power generation efficiency can be improved.

In the present invention, it is also possible that a spiral water pipe is wound on the outer surface of the casing.

By adopting the present invention, the cooling fluid is introduced into the spiral water pipe to cool the shell, so that the heat inside the generator can be effectively transferred to the outside, the temperature difference in the direction of heat transfer can be widened, and the power generation efficiency can be improved.

In the present invention, it is also possible that a U-shaped water pipe is arranged on the outer surface of the housing.

By adopting the present invention, by introducing cooling fluid into the U-shaped water pipe, the heat inside the generator can be effectively transferred to the outside, the temperature difference in the direction of heat transfer can be widened, and the power generation efficiency can be improved.

In the present invention, the heat source may be a heat source having a closed structure.

With the present invention, the heat source has a simple structure and does not need to communicate with the outside, so the thermoelectric generator constructed in this way has a simple structure and is easy to manufacture.

In the present invention, the heat source may also be a heat source having a pipe structure.

With the present invention, the inside of the heat source can be connected with the outside, and waste heat such as exhaust gas can be introduced into the heat source from one end of the casing, and discharged from the other end after heat transfer, so that the generator can use the heat energy to generate electricity.

In the present invention, it is also possible that pipe transfer interfaces or flanges communicating with the pipe structure of the heat source are respectively installed at both ends of the casing in the axial direction.

With the present invention, the inside of the heat source can be connected to the outside through the pipe adapter or flange, and the exhaust waste heat can be easily introduced from one end of the shell to the inside of the heat source, and then discharged from the other end after heat transfer, so that the generator can use this Heat energy produces electricity.

In the present invention, it is also possible that the pipe transfer interface or the flange is made of metal material or high temperature resistant organic material.

Adopting the present invention is beneficial to lead the external heat into the thermoelectric generator, and can improve the power generation efficiency of the whole generator system.

In the present invention, it is also possible that the pipe transfer interface or the flange is connected to the outer shell by screw fastening or welding.

By adopting the present invention, it is possible to more firmly combine the pipe transfer interface or the flange with the shell.

In the present invention, it is also possible that the thermoelectric component is made of SiGe alloy material, skutterudite or filled skutterudite thermoelectric material, ZnSb ₃ -based thermoelectric material, Bi ₂ Te _3- based thermoelectric material, half-Hales (half- Hesuler) compound thermoelectric material composed of a thermoelectric component.

By adopting the invention, heat energy can be effectively converted into electric energy.

In the present invention, it is also possible that the heat collecting member of the thermoelectric power generation system located at the uppermost position in the heat transfer direction is made of graphite or metal material with high thermal conductivity.

By adopting the present invention, the heat collecting performance of the heat collecting member can be improved.

In the present invention, the heat collecting members other than the heat collecting member of the thermoelectric power generation system positioned uppermost in the heat transfer direction may also be made of a highly thermally conductive metal material.

By adopting the invention, the heat collection performance of the heat collection member can be improved, and the heat transfer performance can be further improved, which is beneficial to the thermoelectric conversion of the whole thermoelectric generator.

Preferably, the metal material with high thermal conductivity may be copper, aluminum, or an alloy material.

Description of drawings

FIG. 1 is a schematic diagram of a finned heat dissipation cascaded thermoelectric generator according to a first embodiment of the present invention;

Fig. 2 is the A-A line sectional view of the cascaded thermoelectric generator with fin cooling shown in Fig. 1;

3 is a schematic diagram of a spiral water-cooled cascaded thermoelectric generator according to a second embodiment of the present invention;

Fig. 4 is the B-B sectional view of the spiral water-cooled cascaded thermoelectric generator shown in Fig. 3;

5 is a schematic diagram of a U-shaped water-cooled cascaded thermoelectric generator according to a third embodiment of the present invention;

Fig. 6 is a C-C line sectional view of the U-shaped water-cooled cascaded thermoelectric generator shown in Fig. 5;

Fig. 7 is a schematic diagram of the finned heat dissipation cascaded thermoelectric generator shown in Fig. 1 with a pipeline heat source;

Fig. 8 is a schematic diagram of the spiral water-cooled cascaded thermoelectric generator shown in Fig. 3 with a pipeline heat source;

Fig. 9 is a schematic diagram of the U-shaped water-cooled cascaded thermoelectric generator shown in Fig. 5 with a pipe-type heat source.

Detailed ways

Hereinafter, the present invention will be further described with reference to the accompanying drawings and in conjunction with the following embodiments. It should be understood that the accompanying drawings and the following embodiments are only exemplary to illustrate the present invention, and are not intended to limit the present invention. Within the spirit and scope of the present invention, the following embodiments can be modified in many ways. Wherein, the same components in each embodiment are marked with the same reference numerals and will not be described in detail again.

1 to 9 respectively show various embodiments of the cascaded thermoelectric generator of the present invention. The cascaded thermoelectric generator of the present invention includes a heat source that generates heat, a thermoelectric power generation unit that converts heat into electrical energy, and a casing, wherein the thermoelectric power generation unit includes cascaded thermoelectric generators that are sequentially arranged radially outward from the heat source along the direction of heat transfer. At least two thermoelectric power generation systems, the at least two thermoelectric power generation systems in cascade transfer heat step by step, and the thermoelectric power generation systems at each level use the heat received by them to perform thermoelectric conversion. The cascaded thermoelectric generator provided by the present invention does not use multi-stage composite thermoelectric materials or cascaded thermoelectric power generation devices, but uses cascade connection of multiple thermoelectric power generation systems. The above-mentioned at least two thermoelectric power generation systems in the cascaded thermoelectric generator of the present invention are relatively independent, and when one system fails, the other systems can still work normally.

As shown in Figures 1 to 9, the thermoelectric generators 10, 20, 30 of the present invention can be roughly cylindrical in shape, and a heat source 1 is arranged at the center thereof. 1 After passing through the thermoelectric power generation system in each temperature range to the outer shell 8, it is emitted from the outer shell 8. When the heat passes through the thermoelectric power generation system at various levels, a temperature difference is generated, and then electric energy is generated, and the outermost shell 8 can be used as a cooling device for the entire thermoelectric generator.

By combining two or more independent thermoelectric power generation systems, the present invention expands the working temperature range of the thermoelectric generator and improves the overall efficiency of the thermoelectric generator under the premise of ensuring the reliability of the thermoelectric generator .

More specifically, in the cascaded thermoelectric generator of the present invention, the above-mentioned thermoelectric power generation systems at all levels respectively include heat collectors, thermoelectric devices, and radiators arranged radially outward in sequence along the heat transfer direction, and the high-temperature side of the thermoelectric devices The thermoelectric device is connected to the heat collector and the low-temperature side of the thermoelectric device is connected to the heat sink. The thermoelectric device receives heat from the heat collector for thermoelectric conversion and further transfers heat to the heat sink. The heat collectors and radiators of the thermoelectric power generation system at all levels are cylindrical structures arranged coaxially, and have multiple thermoelectric devices radially distributed between the heat collectors and the radiators.

For the above-mentioned thermoelectric generators, among the adjacent two-stage thermoelectric power generation systems, the radiator of the upper thermoelectric power generation system located in the upper heat transfer direction is the heat collector of the lower thermoelectric power generation system located in the lower heat transfer direction. Because the two-stage thermoelectric power generation system shares the radiator and heat collector, the continuity of heat transfer is guaranteed. When one system is in failure state, the other systems can still work normally.

Moreover, the thermoelectric devices of the thermoelectric power generation system at various levels can be composed of different thermoelectric materials, and the thermoelectric devices (thermoelectric materials) at all levels have different optimal operating temperatures along the direction of the temperature gradient. Since the thermoelectric devices of the thermoelectric power generation system at all levels are at their respective optimal operating temperatures, the maximum energy conversion efficiency can be obtained.

The thermoelectric materials used in the present invention can be SiGe alloy materials, skutterudite or filled skutterudite (such as CoSb _3- based) thermoelectric materials, ZnSb _3- based thermoelectric materials, Bi ₂ Te _3- based thermoelectric materials, half-Hesuler compounds ( Such as ZrNiSn-based, TiCoSb-based, etc.) one of the thermoelectric materials. Among them, the working temperature of SiGe alloy material is 700-1000℃; the working temperature of skutterudite or filled skutterudite thermoelectric material is 350-600℃; the working temperature of ZnSb ₃ -based thermoelectric material is 200-400℃; Bi ₂ Te ₃ The working temperature of the base thermoelectric material is 25-300°C; the working temperature of the half-Hesuler compound is 300-500°C.

Thermoelectric power generation systems at all levels can select thermoelectric materials with different working temperatures according to the temperature at the collector to form thermoelectric devices. In a specific embodiment, for example, when selecting the thermoelectric material of the thermoelectric power generation system located at the uppermost position (high temperature section) in the heat transfer direction, it can be selected according to the temperature of the heat source. When selecting the thermoelectric material of the lower thermoelectric power generation system (low temperature section), it can be selected according to the temperature of the low temperature side of the thermoelectric material of the upper thermoelectric power generation system adjacent to the thermoelectric power generation system.

In the present invention, the heat collector of the first-stage thermoelectric power generation system located at the uppermost position in the heat transfer direction is made of high thermal conductivity material, which can be graphite, copper, aluminum or alloy materials. The first-stage heat collector can be made of high thermal conductivity metal material, which can be copper, aluminum or alloy material. In this way, heat transfer performance can be further improved.

As shown in Figures 2, 4 and 6, in the cascaded thermoelectric generator of the present invention, it also includes a compression fixing between the low-temperature side of the thermoelectric device connected to the thermoelectric power generation system located at the lowest position in the heat transfer direction and the casing device6. Each component in each thermoelectric power generation system can be compressed by the pressing and fixing device 6, so as to maintain good contact between each thermoelectric device and the heat collector to ensure good heat transfer.

In addition, in the cascaded thermoelectric generator of the present invention, it also includes a support member 7 connected to the pressing and fixing device 6 and closely disposed on the inner side of the casing 8 . The pressing and fixing device 6 is connected to the supporting part 7 , and the supporting part 7 is in close contact with the casing 8 of the cascaded thermoelectric generator. The shell 8 is also the overall heat dissipation structure of the whole system. The setting of the support member 7 can not only provide support for the pressing and fixing device 6, but also facilitate heat transfer.

The casing 8 of the thermoelectric generator of the present invention is the heat dissipation structure of the entire thermoelectric generator system, which can be a casing with various heat dissipation structures, and the detailed structure will be described below. Through these heat dissipation structures, heat can be dissipated from the casing quickly, thereby widening the temperature difference of the entire system in the direction of heat transfer and improving the power generation efficiency of the entire power generation system.

Three embodiments of the cascaded thermoelectric generator of the present invention will be described below with reference to the accompanying drawings, and the same components in each embodiment are denoted by the same reference numerals. In the following embodiments, two thermoelectric power generation systems are used, namely a high-temperature section power generation system and a low-temperature section power generation system, but it is not limited thereto, and a combination of three or more is also possible.

Example 1

FIG. 1 is a schematic diagram of a fin-radiated cascaded thermoelectric generator 10 according to the first embodiment of the present invention; FIG. 2 is a cross-sectional view of the fin-dissipated cascaded thermoelectric generator 10 shown in FIG. 1 . As can be seen from Fig. 1 and Fig. 2, the thermoelectric generator 10 has a substantially cylindrical casing 8; a cylindrical heat source 1 coaxial with the casing 8 and generating heat is provided at the center of the casing 8; Between the heat sources 1 is formed a power generation unit that converts heat into electrical energy and is composed of a high-temperature section power generation system and a low-temperature section power generation system. The high-temperature section power generation system includes a cylindrical high-temperature section coaxial with the casing 8 and in close contact with the outer wall of the heat source 1 The heat collector 2, the high-temperature section thermoelectric device (thermoelectric material) 3 arranged radially on the outer surface of the high-temperature section heat collector 2 at a certain interval, and the high-temperature section coaxial with the outer shell 8 and in close contact with the low-temperature end of the high-temperature section thermoelectric device 3 Radiator 4 in the low temperature section, the power generation system in the low temperature section includes a heat collector 4 in the low temperature section shared with the radiator 4 in the high temperature section, and thermoelectric devices 5 in the low temperature section arranged at certain intervals on the outer surface of the heat collector 4 in the low temperature section. Among them, the heat collector 2 in the high-temperature section transfers heat to the thermoelectric device 3 in the high-temperature section, and the thermoelectric device 3 in the high-temperature section generates a temperature difference along the direction of heat transfer, thereby generating electric energy. Connected, the heat continues to be transferred to the thermoelectric device 5 of the low temperature section through the collector 4 of the low temperature section. The thermoelectric device 5 of the low temperature section also generates a temperature difference along the direction of heat transfer, and then generates electric energy, and further transfers heat outward.

In this embodiment, the thermoelectric generator 10 also includes a compression fixing device 6 connected to the low-temperature end of the thermoelectric device 5 in the low-temperature section, and is used to maintain a gap between each thermoelectric device 3, 5 and the two heat collectors 2, 4. Good contact to ensure good heat transfer. In the present invention, the pressing and fixing method of the pressing and fixing device 6 can adopt a screw pressing method or a spring pressing method.

The pressing and fixing device 6 is also connected to a support component 7 , and the support component 7 is in close contact with the housing 8 . The heat continues to transfer through the compression fixing device 6 and the support member 7 , and finally reaches the casing 8 . The support member 7 can not only fix and support the pressing and fixing device 6, but also facilitate heat transfer because it is in close contact with the casing 8.

In addition, in this embodiment, a plurality of radially distributed cooling fins 9 are also formed on the outer surface of the casing 8 . Forming the cooling fins radially at certain intervals on the surface of the housing is beneficial to the cooling of the entire generator. Through these cooling fins 9, the heat can be dissipated from the casing 8 quickly.

More preferably, the thermoelectric device 3 in the high temperature section, the thermoelectric device 5 in the low temperature section, the pressing and fixing device 6 and the cooling fins 9 are formed on a straight line, so that the internal heat can be effectively transferred to the outside, and the direction of heat transfer can be enlarged. The temperature difference improves the power generation efficiency.

The heat source 1 can be a closed type or a pipeline type, and a heat medium such as exhaust waste heat can be used as the heat source. When the heat source 1 is a heat source with a pipe structure, pipe adapters or flanges 12 connected with the pipe structure of the heat source are installed at both axial ends of the housing 8 . FIG. 7 shows a schematic diagram of the fin-radiated cascaded thermoelectric generator shown in FIG. 1 with a pipe-type heat source. It can be seen from Fig. 7 that the inside of the heat source can be connected to the outside through the pipe transfer interface 12, and the waste heat in the exhaust gas can be introduced from one end of the shell 8 into the inside of the heat source, and then discharged from the other end after heat transfer, so that The generator 10 can generate electricity using this thermal energy. The connection between the pipe transfer interface or the flange 12 and the housing 8 can be thread fastening or welding, which can be combined more firmly.

Example 2

Fig. 3 is a schematic diagram of a spiral water-cooled cascade thermoelectric generator according to the second embodiment of the present invention; Fig. 4 is a B-B sectional view of the spiral water-cooled cascade thermoelectric generator shown in Fig. 3; and Fig. 8 is a pipe-type heat source A schematic diagram of a spiral water-cooled cascaded thermoelectric generator shown in Figure 3. As can be seen from Figures 3, 4 and 8, the difference between Embodiment 2 and Embodiment 1 is that a spiral water pipe 11 is wound on the outer surface of the casing 8 of the generator, and other structures identical to Embodiment 1 are in This will not be described in detail. Refrigerating fluid can be introduced into the spiral water pipe 11 to cool the shell. Through the spiral water pipe 11 with cooling effect, the temperature difference of the whole system can be further enlarged, and the power generation efficiency of the whole power generation system can be improved.

Example 3

Fig. 5 is the schematic diagram of the U-shaped water-cooled cascaded thermoelectric generator of the third embodiment of the present invention; Fig. 6 is the C-C line sectional view of the U-shaped water-cooled cascaded thermoelectric generator shown in Fig. 5; A schematic diagram of the U-shaped water-cooled cascaded thermoelectric generators shown in Figure 5 of the heat source. As can be seen from Figures 5, 6 and 9, the difference between Embodiment 3 and Embodiment 1 is that a U-shaped water pipe 13 is arranged on the outer surface of the generator casing 8, and a cooling fluid can be introduced into the U-shaped water pipe 13. , so as to play the role of cooling the shell. Through the U-shaped water pipe 13 with cooling function, the temperature difference of the whole system can be further enlarged, and the power generation efficiency of the whole power generation system can be improved.

Through the heat dissipation structures mentioned above, the heat can be quickly dissipated from the casing, thereby widening the temperature difference of the entire system in the direction of heat transfer and improving the power generation efficiency of the entire power generation system.

The cascaded thermoelectric generator of the invention can particularly effectively convert heat energy into electric energy, has strong system stability and high power generation efficiency.

Claims (20)

1. A cascaded thermoelectric generator, comprising a heat source that generates heat, a thermoelectric power generation unit that converts heat into electrical energy, and a housing, wherein the thermoelectric power generation unit includes a series of heat sources along the heat transfer direction from the heat source. At least two thermoelectric power generation systems cascaded outwardly, the at least two thermoelectric power generation systems in cascade transfer heat step by step, and the thermoelectric power generation systems of each stage use the heat received by them to perform thermoelectric conversion. 2. The cascaded thermoelectric generator according to claim 1, characterized in that, the thermoelectric power generation systems at all levels respectively comprise a heat collecting member, a thermoelectric member and a heat dissipation member arranged radially outward along the heat transfer direction, said The high-temperature side of the thermoelectric component is connected to the heat-collecting component and the low-temperature side of the thermoelectric component is connected to the heat-dissipating component, and the thermoelectric component receives heat from the heat-collecting component for thermoelectric conversion and further transfers heat to the heat-dissipating component transfer heat. 3. The cascaded thermoelectric generator according to claim 2, characterized in that, in the adjacently arranged two-stage thermoelectric power generation systems, the heat dissipation member of the upper stage thermoelectric power generation system positioned on the heat transfer direction is located at the heat transfer The heat collecting component of the next-level thermoelectric power generation system in the lower direction. 4. The cascaded thermoelectric generator according to claim 2, characterized in that the thermoelectric power generation systems at each stage select thermoelectric components with different working temperatures according to the temperature at the heat collecting components. 5. The cascaded thermoelectric generator according to claim 2, characterized in that the heat-collecting components and heat-dissipating components of the thermoelectric power generation systems at all levels are cylindrical structures coaxially arranged, and the thermoelectric components are a plurality of radial Thermoelectric devices distributed between the heat collecting member and the heat dissipating member. 6 . The cascaded thermoelectric generator according to claim 2 , wherein the heat dissipation component of the thermoelectric power generation system at the lowest position in the heat transfer direction is the casing of the cascaded thermoelectric generator. 7 . 7. The cascaded thermoelectric generator according to claim 6, further comprising a connection between the low-temperature side of the thermoelectric component of the thermoelectric power generation system located at the lowest position in the heat transfer direction and the housing to The pressing and fixing device for pressing each component in each thermoelectric power generation system. 8 . The cascaded thermoelectric generator according to claim 7 , further comprising a support member connected to the pressing and fixing device and closely attached to the inner side of the casing. 9 . 9 . The cascaded thermoelectric generator according to claim 7 , wherein the pressing and fixing device presses each component in each thermoelectric power generation system by means of screw pressing or spring pressing. 10 . 10 . The cascaded thermoelectric generator according to claim 1 , wherein a plurality of radially distributed cooling fins are formed on the outer surface of the housing. 11 . 11. The cascaded thermoelectric generator according to claim 1, characterized in that a spiral water pipe is wound on the outer surface of the housing. 12. The cascaded thermoelectric generator according to claim 1, characterized in that, a U-shaped water pipe is arranged on the outer surface of the casing. 13. The cascaded thermoelectric generator according to claim 1, wherein the heat source is a heat source with a closed structure. 14. The cascaded thermoelectric generator according to claim 1, wherein the heat source is a heat source with a pipe structure. 15 . The cascaded thermoelectric generator according to claim 14 , characterized in that, pipe transfer interfaces or flanges communicating with the pipe structure of the heat source are respectively installed at both axial ends of the housing. 16 . 16. The cascaded thermoelectric generator according to claim 15, characterized in that, the pipe transfer interface or flange is made of metal material or high temperature resistant organic material. 17. The cascaded thermoelectric generator according to claim 14, characterized in that, the pipe transfer interface or flange is connected to the casing by screw fastening or welding. 18. The cascaded thermoelectric generator according to any one of claims 2 to 9, wherein the thermoelectric component is made of SiGe alloy material, skutterudite or filled skutterudite thermoelectric material, ZnSb ₃ -based A thermoelectric component composed of one of thermoelectric materials, Bi ₂ Te ₃ -based thermoelectric materials, and semi-Hallasian compound thermoelectric materials. 19. The cascaded thermoelectric generator according to any one of claims 2 to 9, characterized in that the heat collecting components of the thermoelectric power generation system located at the uppermost position in the heat transfer direction are made of graphite or metal materials with high thermal conductivity . 20. The cascaded thermoelectric generator according to claim 19, characterized in that, the heat collecting members except the heat collecting member of the thermoelectric power generation system located at the uppermost position in the heat transfer direction are made of high thermal conductivity metal materials.

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