Tractor tail gas pipe waste heat recovery device and assembling method

Abstract

The tractor tail gas pipe waste heat recovery device comprises a tractor tail gas pipe, a thermal interface material layer, a flexible thermoelectric device and a stretchable heat dissipation water jacket, the flexible thermoelectric device comprises a flexible substrate and thermoelectric particles arranged on the flexible substrate, hot end electrodes of the thermoelectric particles are arranged on the flexible substrate, the hot end electrodes are flexible electrodes, and the stretchable heat dissipation water jacket is arranged on the flexible substrate. The flexible substrate can bend and deform along with the flexible substrate; the flexible thermoelectric device can wrap the outer side of the tractor tail gas pipe, the tractor tail gas pipe and the flexible thermoelectric device are tightly matched and attached through the thermal interface material layer, an additional heat conduction expansion structure is not needed, the thickness is smaller, and the mass is lighter. The stretchable heat dissipation water jacket is of a tubular structure and is arranged on the outer side of the flexible thermoelectric device in a sleeving mode, the flexible thermoelectric device is pressed and fixed to the surface of the tractor tail gas pipe through pre-tightening force generated by elastic contraction of the stretchable heat dissipation water jacket, the assembly process is simplified, it is ensured that tight thermal interface contact is formed between the flexible thermoelectric device and the heat dissipation water jacket, and interface contact thermal resistance is remarkably reduced.

Description

Technical Field

[0001] The invention relates to a tractor exhaust waste heat recovery technology, in particular to a tractor exhaust pipe waste heat recovery device and an assembly method. Background Art

[0002] In recent years, with the rapid development of the agricultural machinery industry, improving energy efficiency and reducing carbon emissions have become important research areas for internal combustion engine technology. According to statistics, approximately 30%-40% of the energy generated by fuel combustion in traditional internal combustion engines is lost to the environment in the form of high-temperature exhaust gases, resulting in energy waste and exacerbating the greenhouse effect. Currently, mainstream exhaust heat recovery technologies include exhaust gas turbocharging, the Rankine cycle, and thermoelectric power generation. Among these, thermoelectric power generation technology based on the Seebeck effect has attracted considerable attention due to its compact structure, lack of moving parts, and environmental friendliness. It can directly convert the temperature difference between exhaust gas and the surrounding environment into electrical energy, with the recovered energy used to power intelligent sensing equipment, thus offering significant application potential.

[0003] Existing research has mostly focused on commercial vehicles and urban road conditions. However, tractors, under complex vibration, high-temperature dust and intermittent load conditions, have higher requirements for the shock resistance, reliability and environmental adaptability of thermoelectric devices.

[0004] Traditional thermal power recovery systems use rigid flat-plate thermoelectric devices, requiring structural modifications to the tailpipe. This requires the addition of outward-extending heat-conducting components to create a mounting surface for the flat-plate thermoelectric devices, resulting in a bulky design, complex processes, and difficult installation. In this structure where the flat-plate thermoelectric device is installed around the tailpipe, different parts of the flat-plate thermoelectric device are at different distances from the circular tailpipe. These differences in heat conduction paths lead to different temperatures across the device, impacting waste heat recovery efficiency. Furthermore, the rigid flat-plate device inevitably leads to interface mismatching issues, resulting in a high thermal resistance with the curved tailpipe, limiting heat transfer efficiency.

[0005] Similarly, the cold-end radiator of the existing system also adopts a rigid structure (such as metal fins or water-cooled plates), which has a long heat transfer path, large volume and weight, and has the limitation of poor interface matching with thermoelectric devices, resulting in low overall heat utilization. The larger volume and weight of the installation may also increase the energy consumption of the entire vehicle.

[0006] In this rigid structure thermoelectric recovery system, the thermoelectric devices and radiators are arranged in segments and intervals. The structure has poor integrity, is heavy and unevenly distributed, resulting in poor vibration resistance and making it difficult to use on tractors with complex vibration conditions. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the defects of the existing tailpipe waste heat recovery device, such as large size, poor compatibility with the tailpipe affecting waste heat recovery efficiency, and poor vibration resistance, and to provide a tractor tailpipe waste heat recovery device and an assembly method.

[0008] The technical solution adopted by the present invention to solve the above technical problems is: a tractor exhaust pipe waste heat recovery device, including a tractor exhaust pipe, a thermal interface material layer, a flexible thermoelectric device and a stretchable heat dissipation water jacket, the flexible thermoelectric device including a flexible substrate wrapped around the outside of the tractor exhaust pipe and thermoelectric particles arranged on the flexible substrate, the hot end electrode of the thermoelectric particles arranged on the flexible substrate, the hot end electrode being a flexible electrode capable of bending and deforming along with the flexible substrate wrapped around the outside of the tractor exhaust pipe; a thermal interface material layer capable of filling the gap between the flexible substrate and the outer wall of the tractor exhaust pipe and conducting heat is provided between the flexible substrate and the outer wall of the tractor exhaust pipe; the stretchable heat dissipation water jacket is a tubular structure, which is sleeved on the outside of the flexible thermoelectric device and fixes the flexible thermoelectric device to the tractor exhaust pipe through the pre-tightening force of elastic contraction.

[0009] A heat-conducting fixing tape layer is wrapped around the outside of the flexible thermoelectric device wrapped around the tractor's tailpipe to cover the cold end of the thermoelectric particles and encapsulate and fix them.

[0010] The flexible electrode is made of conductive metal foil.

[0011] When the stretchable heat dissipation water jacket is in a free and unstretched state, its inner diameter is smaller than the outer diameter of the tractor exhaust pipe wrapped with the flexible thermoelectric device.

[0012] The stretchable heat dissipation water jacket is provided with a flow channel connected to the cooling water circulation pipeline.

[0013] The flow channel extends along the axial direction of the stretchable heat dissipation water jacket. When the stretchable heat dissipation water jacket is in a free and unstretched state, the cross-section of the flow channel is a trapezoid with a smaller side close to the tractor exhaust pipe and a larger side. After the stretchable heat dissipation water jacket is put on the outside of the flexible thermoelectric device, the side of the flow channel close to the tractor exhaust pipe is stretched.

[0014] The stretchable heat dissipation water jacket is formed by compositely preparing a high thermal conductivity material and a flexible stretchable material.

[0015] The high thermal conductivity material is made of metal particles or liquid metal, which is embedded with the flexible stretchable material to form a stretchable heat dissipation water jacket.

[0016] A method for assembling a waste heat recovery device for a tractor exhaust pipe comprises the following steps: coating the outer side of the tractor exhaust pipe or the lower surface of the flexible substrate of a flexible thermoelectric device with a thermal interface material, then covering and wrapping the flexible thermoelectric device on the outer circumferential surface of the tractor exhaust pipe; applying a certain pressure so that the thermal interface material fills the gap between the flexible thermoelectric device and the outer wall of the tractor exhaust pipe; after fixing the flexible thermoelectric device, expanding a stretchable heat dissipation water jacket and fitting it onto the outer side of the flexible thermoelectric device; and utilizing the elastic contraction force of the stretchable heat dissipation water jacket to wrap and fix the flexible thermoelectric device.

[0017] After the flexible thermoelectric device is wrapped around the tractor exhaust pipe, a thermally conductive fixing tape is wrapped around the outside of the flexible thermoelectric device to cover the cold end of the thermoelectric particles of the flexible thermoelectric device to encapsulate the outer surface of the flexible thermoelectric device, and then a stretchable heat dissipation water jacket is installed.

[0018] The present invention has the following beneficial effects: the flexible thermoelectric device utilizes a flexible substrate and flexible electrodes to form a bendable and deformable structure that can be wrapped around the outside of a tractor exhaust pipe. A thermal interface material layer ensures a tight fit between the tractor exhaust pipe and the flexible thermoelectric device, eliminating the need for an additional thermally conductive extension structure and resulting in a thinner and lighter device. The flexible thermoelectric device is secured by a stretchable heat-dissipating jacket. This elastic jacketing significantly simplifies the assembly process and, through the continuous application of a preload, ensures a tight thermal interface between the flexible thermoelectric device and the heat-dissipating jacket, significantly reducing the interfacial thermal resistance between the two.

[0019] While reducing thermal resistance and improving thermoelectric conversion efficiency, the flexible thermoelectric device and stretchable heat dissipation water jacket wrapped around the tractor's tailpipe have good structural integrity in the circumferential direction of the tailpipe, and the weight is evenly distributed in the circumferential direction of the tailpipe. The elastic wrapping of the stretchable heat dissipation water jacket also gives it better vibration resistance, which can meet the needs of the tractor's complex vibration working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the waste heat recovery device of the present invention.

[0021] Figure 2 yes Figure 1 Schematic diagram of the partially cutaway state of the waste heat recovery device.

[0022] Figure 3 Schematic diagram of the flexible thermoelectric device of the present invention.

[0023] Figure 4 Schematic diagram of a thermoelectric unit in a flexible thermoelectric device.

[0024] Figure 5 Schematic diagram of a first embodiment of the stretchable heat dissipation water jacket of the present invention.

[0025] Figure 6 It is a schematic diagram of a stretchable heat dissipation water jacket mold.

[0026] Figure 7 Schematic diagram of the second embodiment of the stretchable heat dissipation water jacket.

[0027] Figure 8 Schematic diagram of the third embodiment of the stretchable heat dissipation water jacket.

[0028] Figure 9 It is a schematic diagram of the S-shaped flow channel of the stretchable heat dissipation water jacket.

[0029] Figure 10 This is a schematic diagram of the S-shaped flow channel of the stretchable heat dissipation water jacket after stretching Figure 11 This is a schematic diagram of the coordinated structure of the flexible thermoelectric device and the tractor exhaust pipe.

[0030] Markings in the figure: 1. Tractor exhaust pipe; 2. Thermal interface material layer, 3. Flexible thermoelectric device, 4. Stretchable heat dissipation water jacket, 401, flow channel, 5. Thermoelectric particles, 6. Flexible substrate, 7. Hot end electrode, 8. Cold end electrode, 9. Stretchable water jacket mold. DETAILED DESCRIPTION

[0031] The following is a clear and complete description of the technical solution of the present invention in conjunction with the accompanying drawings and specific embodiments. The specific contents listed in the following embodiments are not limited to the technical features required to solve the technical problems to be solved by the technical solutions described in the claims. At the same time, the examples listed are only part of the present invention, not all embodiments.

[0032] Figure 1 The figure shows a schematic structural diagram of the waste heat recovery device for a tractor exhaust pipe according to the present invention, which includes a flexible thermoelectric device 3 and a stretchable heat dissipation water jacket 4 arranged outside the tractor exhaust pipe 1. Figure 2 for Figure 1 As shown in a partial cross-section of a tractor exhaust pipe, the flexible thermoelectric device 3 comprises a flexible substrate 6 and thermoelectric particles 5. The flexible substrate 6 is wrapped around the outside of the tractor exhaust pipe 1. A thermal interface material layer 2 is provided between the flexible substrate 6 and the outer wall of the tractor exhaust pipe 1. This thermal interface material layer 2 is made of a material with high thermal conductivity, such as thermal grease, phase change material, or liquid metal thermal interface material. This thermal interface material layer 2 fills the gap between the flexible substrate 6 and the outer wall of the tractor exhaust pipe 1, ensuring a tight fit and facilitating heat transfer.

[0033] like Figure 3 As shown, the flexible substrate 6 of the flexible thermoelectric device 3 is made of flexible material and can be stretched and laid out to facilitate the assembly and welding of components such as the thermoelectric particles 5, and can be Figure 2 and Figure 11The flexible substrate is shown wrapped around the outside of the tractor exhaust pipe 1. The flexible substrate is made of a material with excellent flexibility, strong insulation, and high temperature resistance, such as polyimide film, liquid crystal polymer film, and polyethylene naphthalate film. Thermoelectric particles 5 are elements with a thermoelectric effect. They are arranged on the flexible substrate and connected to corresponding electrodes to form a thermoelectric element, which is used to convert heat from the tractor exhaust pipe into electrical energy. Figure 4 The figure shows a basic thermoelectric effect element, which encapsulates two thermoelectric particles 5. The hot ends of the two thermoelectric particles 5 face and are connected to hot-end electrodes 7, respectively. The cold ends of the two thermoelectric particles 5 face upward and are connected via cold-end electrodes 8. The thermoelectric particles are made of thermoelectric materials with high thermoelectric merit, including but not limited to skutterudite-based compounds such as Yb0.3Co4Sb12 and CeFe4Sb12, formed by filling a CoSb3 matrix with rare earth elements such as Yb and Ce; cage-structured compounds such as Ba8Ga16Ge30 and Sr8Ga16Ge30; Bi2Te3 / Sb2Te3 superlattice films; GeTe-based high-entropy alloys; and telluride-based materials such as PbTe-SrTe nanocomposites, which can improve energy conversion efficiency. The hot end of the thermoelectric particle 5 faces the flexible substrate 6, and the cold end faces outward. The hot end electrode 7 is a flexible electrode. The flexible electrode is arranged on the flexible substrate 6 and can bend and deform with the flexible substrate 6, so that the flexible substrate 6 has good bending performance, so that it can be wrapped around the outside of the tractor exhaust pipe 1. The hot end electrode 7 is made of materials with good flexibility and high electrical conductivity, including but not limited to conductive metal foil, such as rolled annealed copper foil. If other electrical connection methods besides welding are used, other materials such as graphene materials can also be used as flexible electrodes. The thermoelectric effect element composed of multiple thermoelectric particles is arranged according to Figure 3 In the array arrangement shown, the hot-end electrode 7 and the flexible substrate 6 between the thermoelectric particles are both highly flexible, and the upper ends of the two thermoelectric elements are spaced apart and not connected. This makes the flexible thermoelectric device 3 highly flexible and can be bent in both the horizontal and vertical directions, enabling its application on a variety of complex curved surfaces. Compared to rigid thermoelectric devices, it not only conforms to curved surfaces, reducing interfacial thermal resistance, but is also thinner and lighter.

[0034] The preparation process of the flexible thermoelectric device 3 mainly includes four steps. First, the hot end electrode 7 required for the flexible thermoelectric device 3 is prepared on the flexible substrate 6. Second, solder paste is evenly applied to the hot end electrode 7 using a steel mesh. Then, the thermoelectric particles 5 are accurately placed on the hot end electrode 7 coated with solder paste using a placement machine, and the attached device is placed in a reflow soldering machine for soldering. Finally, the soldered part is accurately covered with fixing tape with the cold end electrode 8, and after soldering again, the preparation of the flexible thermoelectric device is completed. It should be noted that the size of the hot end electrode 7 and the cold end electrode 8 must be designed according to the size of the thermoelectric particles 5 to facilitate the subsequent placement operation.

[0035] To encapsulate and protect the thermoelectric particles 5, the flexible thermoelectric device 3 is wrapped with a layer of thermally conductive securing tape. This tape, which can be made of a high-thermal-conductivity adhesive tape such as graphene tape, is applied after the flexible thermoelectric device 3 is wrapped around the tractor exhaust pipe 1. This layer of thermally conductive securing tape is applied to the flexible thermoelectric device 3 and does not affect its bending or deformation. By wrapping the thermally conductive securing tape around the cold end of the thermoelectric particles 5, it is encapsulated and secured.

[0036] like Figure 5 As shown, the stretchable heat dissipation water jacket 4 is a tubular structure, and a flow channel 401 connected to the cooling water circulation pipeline is provided inside the stretchable heat dissipation water jacket 4. Figure 2 As shown, the stretchable heat dissipation jacket 4 is placed over the flexible thermoelectric device 3. In its free, unstretched state, the inner diameter of the stretchable heat dissipation jacket 4 is smaller than the outer diameter of the tractor exhaust pipe 1 encasing the flexible thermoelectric device 3. Once placed over the flexible thermoelectric device 3, the stretchable heat dissipation jacket 4 elastically contracts inward. The preload from this elastic contraction not only secures the flexible thermoelectric device 3 to the tractor exhaust pipe 1 without requiring excessive assembly and fixing components, but also ensures good adhesion to the uneven surface of the thermoelectric particles, thereby reducing the interfacial thermal resistance between the two.

[0037] The cross-sectional shape of the flow channel of the stretchable heat dissipation jacket affects its heat exchange area and should be selected according to the heat dissipation requirements. Figure 5 As shown, in the free and unstretched state, the cross section of the flow channel 401 is a trapezoid with a smaller side close to the tractor exhaust pipe and a larger side. Figure 2 As shown, the flow channel is stretched on one side close to the tractor exhaust pipe, and the trapezoidal flow channel 401 cross section becomes approximately elliptical. After stretching, the width and inner wall thickness of the flow channel decrease, but the length and outer wall thickness increase. After stretching, the thermal conductivity of the stretchable heat dissipation water jacket will be improved to a certain extent, which can further reduce the conduction thermal resistance. The increase in the flow channel area will increase the heat exchange area between the flow channel and the fluid, further reducing the convection thermal resistance. The flow channel cross section of the stretchable heat dissipation water jacket can also be as follows Figure 7 Set as a prism as shown, or as Figure 8 The setting shown is circular.

[0038] The flow channel configuration of the stretchable heat dissipation water jacket is related to the drive control mode. The overall flow channel configuration can be S-shaped or straight. Under the condition of controlling the same inlet flow rate, the straight flow channel has the relatively best heat dissipation performance and thermoelectric conversion power output characteristics; under the condition of controlling the same volume flow rate, such as Figure 9 and 10 The S-shaped flow channel shown has relatively optimal heat dissipation performance and thermoelectric conversion power output characteristics.

[0039] The stretchable heat dissipation water jacket is prepared and formed by a composite of a high thermal conductivity material and a flexible stretchable material. The high thermal conductivity material and the flexible stretchable material form a mosaic structure, which combines the elasticity of the flexible stretchable material and the thermal conductivity of the high thermal conductivity material to achieve elastic installation and high thermal conductivity efficiency of the stretchable heat dissipation water jacket. The thermal conductivity of the flexible composite material is positively correlated with the proportion of the doped high thermal conductivity material, but if the mass of the high thermal conductivity material is too large, there will be a problem of uneven mixing, which affects the molding of the composite material. The high thermal conductivity material can be selected from metal or oxide particles, such as copper powder, etc., or liquid metals, such as gallium, indium and their alloys, as needed. The flexible stretchable material can be selected from silicone rubber, modified rubber, thermoplastic elastomer TPE, thermoplastic rubber TPR, etc. The specific amount is determined according to the selected high thermal conductivity material and the specific gravity and other properties of the flexible stretchable material, such as 1:1, 2:1, 3:1 and 4:1.

[0040] Stretchable heat dissipation jackets can be manufactured using molds. The main steps include intercalating a high-thermal-conductivity composite material, printing and pre-treating the stretchable jacket mold, and pressure-filling molding. For example, using a metal particle high-thermal-conductivity material, the high-thermal-conductivity material and a flexible stretchable material are first mixed in a specific proportion. After ultrasonic dispersion to form a uniformly dispersed intercalated system, the mixture is placed in a vacuum drying oven and evacuated to remove microbubbles from the high-thermal-conductivity composite material to prevent the accumulation of air bubbles. The stretchable jacket mold can be manufactured using 3D printing technologies, such as fused deposition modeling and stereolithography. Materials used for 3D printing include, but are not limited to, polylactic acid, acrylonitrile-butadiene-styrene copolymer, and nylon. The stretchable jacket mold is printed using a 3D printer, and the interior and exterior surfaces are cleaned using an ultrasonic vibration cleaner. A release agent is then sprayed onto the interior to facilitate mold removal. After evacuation, the high-thermal-conductivity composite material is poured into the jacket mold and pressure-filled to form the mold. The specific molding conditions and required additives for the high-thermal-conductivity composite material depend on the selected material type and can be referenced in existing technologies. If liquid metal is used as a high thermal conductivity material, due to the characteristics of liquid metal material being liquid at room temperature, the liquid metal can be first pumped into a 3D printing mold to shape it, and then a flexible stretchable material can be pumped into another 3D printing mold to form it.

[0041] Before assembling the tractor exhaust pipe waste heat recovery device of the present invention, the surface of the tractor exhaust pipe 1 must be cleaned to ensure good contact between the thermoelectric device and the tractor exhaust pipe. A thermal interface material is then applied to the outer surface of the tractor exhaust pipe or the lower surface of the flexible thermoelectric device's flexible substrate. After evenly applying the material, the flexible thermoelectric device 3 is wrapped around the outer circumference of the tractor exhaust pipe 1. During installation, a certain amount of pressure is applied to ensure close and uniform contact between the flexible thermoelectric device 3 and the surface of the tractor exhaust pipe 1. The thermal interface material fills the gap between the flexible thermoelectric device 3 and the outer wall of the tractor exhaust pipe 1, forming a thermal interface material layer 2. Adhesive tape is then used to secure the front and rear sides of the thermoelectric device substrate to the exhaust pipe surface. To encapsulate and protect the thermoelectric particles, after wrapping the flexible thermoelectric device around the tractor exhaust pipe, a high-thermal-conductivity thermally conductive adhesive tape (such as graphene tape) is wrapped around the outer surface of the flexible thermoelectric device. A certain amount of preload is applied during the encapsulation process to prevent the solder paste from melting at high temperatures and loosening the thermoelectric particles 5. After fixing the flexible thermoelectric device 3, the central through hole of the stretchable heat dissipation water jacket 4 is expanded and it can be put on the outside of the flexible thermoelectric device 3. Due to the flexibility and elastic contraction of the stretchable heat dissipation water jacket 4, the stretchable heat dissipation water jacket 4 can fit tightly with the flexible thermoelectric device 3 and play the role of fixing the flexible thermoelectric device. The flow channel of the stretchable heat dissipation water jacket 4 is connected to the external cooling water circulation pipeline through a reserved interface, and the cooling water circulation pipeline can be provided with circulation power by a water pump. After the cooling water is introduced into the flow channel and the static water pressure is introduced, the heat exchange area can be further increased and the inner wall thickness can be reduced, greatly reducing the heat conduction and heat convection thermal resistance of the stretchable heat dissipation water jacket. The cooling water is introduced into the stretchable heat dissipation water jacket from the water inlet and flows out from the water outlet, ensuring that the cooling water can fully flow through the stretchable heat dissipation water jacket 4 to take away its heat energy, ensuring the temperature difference between the hot and cold ends of the thermoelectric device, thereby realizing the conversion of heat energy into electrical energy.

[0042] Considering factors such as thermoelectric conversion efficiency and the heat resistance and service life of the waste heat recovery device, the device was installed on the tractor's exhaust pipe, which normally operates in a temperature range of 150-300°C. The energy harvested by the device provides a long-term power supply for intelligent sensing equipment, which can be used to monitor tractor operating parameters and farmland environmental parameters in real time, including but not limited to atmospheric temperature and humidity, soil temperature and humidity, tillage depth, operating speed, vegetation index, and GPS positioning information.

[0043] The above description of the specific embodiments is only used to help understand the technical concept and core ideas of the present invention. Although specific preferred embodiments are used herein to describe and illustrate the technical solutions, they should not be understood as limiting the present invention itself. Those skilled in the art may make various changes in form and details without departing from the technical concept of the present invention. These easily conceived changes or substitutions should all be included within the scope of protection of the present invention.

Claims

1. A tractor exhaust pipe waste heat recovery device, characterized by: The invention comprises a tractor tailpipe (1), a thermal interface material layer (2), a flexible thermoelectric device (3) and a stretchable heat dissipation water jacket (4), wherein the flexible thermoelectric device (3) comprises a flexible substrate (6) wrapped around the outside of the tractor tailpipe (1) and thermoelectric particles (5) arranged on the flexible substrate, a hot end electrode (7) of the thermoelectric particles (5) arranged on the flexible substrate (6), and the hot end electrode (7) is a flexible electrode capable of bending and deforming along with the flexible substrate (6) wrapped around the outside of the tractor tailpipe (1); a thermal interface material layer (2) capable of filling a gap between the flexible substrate (6) and the outer wall of the tractor tailpipe (1) and conducting heat is provided between the flexible substrate (6) and the outer wall of the tractor tailpipe (1); the stretchable heat dissipation water jacket (4) is a tubular structure, which is sleeved on the outside of the flexible thermoelectric device (3) and fixes the flexible thermoelectric device (3) on the tractor tailpipe (1) through a pre-tightening force of elastic contraction.

2. The tractor exhaust pipe waste heat recovery device according to claim 1, characterized in that: A heat-conducting fixing tape layer is wrapped around the outside of the flexible thermoelectric device (3) wrapped around the tractor tailpipe (1) and covers the cold end of the thermoelectric particles (5) to encapsulate and fix them.

3. The tractor exhaust pipe waste heat recovery device according to claim 1, characterized in that: The flexible electrode is made of conductive metal foil.

4. The tractor exhaust pipe waste heat recovery device according to claim 1, characterized in that: When the stretchable heat dissipation water jacket (4) is in a free, unstretched state, its inner diameter is smaller than the outer diameter of the tractor exhaust pipe (1) encasing the flexible thermoelectric device (3).

5. The tractor exhaust pipe waste heat recovery device according to claim 1, characterized in that: The stretchable heat dissipation water jacket (4) is provided with a flow channel (401) connected to a cooling water circulation pipeline.

6. The tractor exhaust pipe waste heat recovery device according to claim 5, characterized in that: The cross-sectional shape of the flow channel is circular, trapezoidal or prismatic, and the overall configuration of the flow channel is S-shaped or straight.

7. The tractor exhaust pipe waste heat recovery device according to claim 1, characterized in that: The stretchable heat dissipation water jacket is formed by compositely preparing a high thermal conductivity material and a flexible stretchable material.

8. The tractor exhaust pipe waste heat recovery device according to claim 7, characterized in that: The high thermal conductivity material is made of metal particles or liquid metal, which is embedded with the flexible stretchable material to form a stretchable heat dissipation water jacket.

9. The method for assembling a tractor exhaust pipe waste heat recovery device according to any one of claims 1 to 8, characterized in that: After applying a thermal interface material on the outside of the tractor tailpipe (1) or the lower surface of the flexible substrate (6) of the flexible thermoelectric device (3), the flexible thermoelectric device (3) is covered and wrapped on the outer circumferential surface of the tractor tailpipe (1), and a certain pressure is applied so that the thermal interface material fills the gap between the flexible thermoelectric device (3) and the outer wall of the tractor tailpipe (1); after fixing the flexible thermoelectric device (3), the stretchable heat dissipation water jacket (4) is stretched and sheathed on the outside of the flexible thermoelectric device (3), and the flexible thermoelectric device is wrapped and fixed by utilizing the elastic contraction force of the stretchable heat dissipation water jacket.

10. The method for assembling a tractor exhaust pipe waste heat recovery device according to claim 9, characterized in that: After the flexible thermoelectric device is wrapped around the tractor exhaust pipe, a thermally conductive fixing tape is wrapped around the outside of the flexible thermoelectric device to cover the cold end of the thermoelectric particles of the flexible thermoelectric device to encapsulate the outer surface of the flexible thermoelectric device, and then a stretchable heat dissipation water jacket is installed.

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