An integrated microchannel water-cooled flexible embedded stretchable thermoelectric device and method of making the same

Abstract

The application discloses a flexible embedded stretchable thermoelectric device integrated with micro-channel water cooling and a preparation method thereof, and belongs to the technical field of thermoelectric device preparation. The flexible water cooling micro-channel preparation process is used to greatly improve the heat dissipation performance of the thermoelectric device, the thermoelectric device no longer needs a complex heat dissipation mechanism, and the refrigeration performance of the thermoelectric device is greatly improved. The embedded thermoelectric arm integration process can miniaturize and integrate the thermoelectric device, and the embedded thermoelectric arm can better contact the microfluid, thereby improving the heat conduction performance. Through the shape design of the stretchable device, the stress is released through the serpentine shape design, the flowability and heat transfer performance of the microfluid are considered through the hexagonal design, and the shape structure can improve the stretchability of the device. The multi-device collaborative process can be used for multiple collaborative use of the device, a thermoelectric device array is formed by a single device, and the application prospect is better.

Description

Technical Field

[0001] This invention belongs to the field of thermoelectric device fabrication technology, specifically relating to a method for fabricating a flexible and stretchable thermoelectric device with integrated microchannel water cooling. Background Technology

[0002] Flexible electronics is an innovative field of electronic technology. Its core concept is to integrate electronic components, circuits, and sensors onto a flexible substrate, thereby endowing these electronic devices with flexible properties such as bending, folding, and stretching. The development of this technology aims to overcome the limitations of traditional rigid electronic devices, providing flexibility and adaptability for electronic devices in a wider range of applications.

[0003] Thermoelectric devices are a class of devices that can convert heat energy into electrical energy (thermoelectric effect) or electrical energy into heat energy (thermal effect). Based on the principles of thermoelectric and thermal effects, they can generate voltage or current when a temperature difference exists, or generate a temperature difference when current flows through them. These devices have potential applications in various fields, including energy harvesting, temperature regulation, and environmental monitoring.

[0004] Flexible thermoelectric devices are a product of combining thermoelectric technology with flexible electronics technology. They possess flexible properties and can operate under bending, folding, and stretching conditions, offering new possibilities for temperature regulation, energy harvesting, and other fields. They hold broad promise for applications such as wearable devices, smart skin, and portable energy harvesting.

[0005] However, current flexible thermoelectric devices still suffer from poor heat dissipation and poor stretchability. Existing flexible thermoelectric devices require large heat sinks to achieve good performance, which greatly limits their flexibility and lightweight characteristics. At the same time, the stretchability of the flexible materials in traditional flexible thermoelectric devices may be limited, which may lead to damage in actual use.

[0006] Therefore, developing a flexible embedded stretchable thermoelectric device with low cost, good tensile properties, good cooling performance, and high integration is of great significance for the practical application of wearable flexible thermoelectric devices. Summary of the Invention

[0007] To address the problems of poor stretchability, inconvenience, and poor cooling performance of wearable thermoelectric cooling devices in the background art, the present invention aims to provide a method for fabricating a flexible and stretchable thermoelectric device with integrated microchannel water cooling. This invention designs a novel wearable thermoelectric cooling device that solves the heat dissipation problem of flexible thermoelectric devices through integrated microchannel water cooling technology, making the device lighter and improving cooling performance. Embedded thermoelectric arm technology improves the thermal conductivity and heat dissipation performance of the device, and the stretchable device shape design enhances its stretchability. The final fabricated device features high flexibility, high integration, small size, and good cooling performance.

[0008] To achieve the above objectives, the preparation scheme of the present invention is as follows: A flexible embedded stretchable thermoelectric device with integrated microchannel water cooling, the device comprising: a flexible substrate, an N-type thermoelectric arm, and a P-type thermoelectric arm; microchannels are disposed on the flexible substrate, the microchannels including an input channel, a heat exchange channel, and an output channel; the heat exchange channel comprises multiple layers of channels from the outside to the inside, each layer of channels being a regular hexagon, but the channel on each side of the regular hexagon is a reciprocating "S" shape; when a virtual straight line is drawn from the center of the regular hexagon, the "S" shaped bending directions of adjacent heat exchange channels on the virtual straight line are opposite; the input channel and the output channel are directly connected through a pair of opposite diagonals of the regular hexagon, the center point of the regular hexagon being the dividing point, one side being the input channel and the other being the output channel. The width of the outflow channel and the inflow channel decreases after each heat exchange channel layer starting from the inlet, while the width of the output channel increases after each heat exchange channel layer starting from the port connecting to the inflow channel. N-type thermoelectric arms and P-type thermoelectric arms are sequentially spaced on both sides of the heat exchange channels. The N-type and P-type thermoelectric arms are cylindrical, with half embedded in the flexible substrate. The positions of the N-type and P-type thermoelectric arms correspond to the "S"-shaped recesses of the heat exchange channels. Metal patches are provided at the bottom and top of the N-type and P-type thermoelectric arms. The bottom or top metal patches of adjacent N-type and P-type thermoelectric arms are connected by "S"-shaped electrodes, ultimately achieving a series connection of all N-type and P-type thermoelectric arms at intervals.

[0009] Furthermore, the connection method of the N-type thermoelectric arm and the P-type thermoelectric arm is as follows: first, the thermoelectric arms in each loop are connected in series, and then the loops are connected in series.

[0010] Furthermore, the flexible substrate is made of a mixture of PDMS, AlN, and curing agent in a ratio of 10:4:1, and the S-shaped electrode is made of copper foil with a total thickness not exceeding 50 μm.

[0011] A method for fabricating a flexible, embedded, stretchable thermoelectric device with integrated microchannel water cooling, the method comprising:

[0012] Step 1. Design a microchannel complementary mold using 3D modeling software and 3D print it. After printing, perform mold pretreatment. Divide the flexible substrate into a lower layer and an upper layer. The lower and upper layers have the same structure. Use the same mold for preparation. The specific steps are as follows: wipe the mold with alcohol to remove a large amount of residual resin, soak it in alcohol and use ultrasonic cleaning to remove residual resin, then place the mold in an oven to bake, and finally use ultraviolet light to cure to obtain a pourable mold.

[0013] Step 2. Mix PDMS, AlN and curing agent to obtain AlN-doped PDMS. Then pour the obtained AlN-doped PDMS into the mold obtained in Step 1 and place it in an oven to cure. After curing, the AlN-doped PDMS is removed from the mold to obtain half of the substrate.

[0014] Step 3. The AlN-doped PDMS from Step 2 is uniformly coated onto a glass slide coated with a release agent. After spin coating on a spin coater, an uncured AlN-doped PDMS film is obtained. This film is used to bond two substrates prepared in Step 2. After the film cures, the desired flexible substrate with microchannels is obtained.

[0015] Step 4. Using the same method as in Step 3, fabricate an AlN-doped PDMS film. Then, place the film on an oven and heat it to obtain a cured AlN-doped PDMS film. Adhere the copper foil with polyimide to the water-soluble adhesive tape, and then fix the water-soluble adhesive tape to the glass slide. Use an ultraviolet laser engraving machine to etch out the serpentine circuit and thermoelectric arm electrodes required for the device. Then, transfer the etched circuit onto the prepared PDMS film and heat it. After washing off the water-soluble adhesive, the printed circuit PDMS film is obtained.

[0016] Step 5. Use an ultraviolet laser engraving machine to etch the flexible substrate obtained in step 3. Design the etched holes according to the electrode arrangement of the thermoelectric device and the shape of the microchannel. Use an ultraviolet laser engraving machine to penetrate the flexible substrate. Then, embed the N-type thermoelectric arm and the P-type thermoelectric arm at intervals of 1 / 2 into the holes respectively. Use the uncured AlN-doped PDMS obtained in step 3 to fill the gap between the thermoelectric arm and the microchannel hole.

[0017] Step 6. Two PDMS films of printed circuit obtained in Step 4 are respectively applied to the bottom and top of the N-type thermoelectric arm and the P-type thermoelectric arm, with the bottom being the part embedded in the substrate; then the circuit is soldered to the thermoelectric arm, and after soldering, the circuit is encapsulated using the AlN-doped PDMS obtained in Step 2.

[0018] Furthermore, the packaging method for the top circuit in step 6 is as follows: the top of the device after the circuit is soldered is attached to the glass substrate with water-soluble adhesive, and then AlN-doped PDMS is used to seal the side of the thermoelectric arm and the PDMS film of the top printed circuit through a spin coating process.

[0019] Furthermore, in step 1, the resin material used for 3D printing is a rigid photocurable resin, the alcohol concentration used to clean the residual resin is 75%, and the oven temperature is 60℃; in step 2, after obtaining AlN-doped PDMS, it needs to be placed in a vacuum machine for 30 minutes to remove air bubbles. After the silicone is poured into the mold, it also needs to be placed in a vacuum machine for 30 minutes to remove residual air bubbles and also to make the silicone adhere better to the mold. Then, it is placed in an oven at 60℃ for 24 hours to cure.

[0020] Furthermore, in step 3, the glass sheet after spraying the release agent needs to be placed on an oven at 220°C and heated for 5 minutes. The spin coater is then used to spin coat at 500 r / min for 2 minutes. After that, it needs to be vacuumed and combined with microchannel A. During the combination and curing, it is placed on an oven at 150°C for 10 minutes. In step 4, the overall thickness of the copper foil used to bond the polyimide does not exceed 50 μm. The electrode base of the thermoelectric arm is designed to be 1.2 mm * 1.2 mm in size, and the "S"-shaped circuit line width is 0.2 mm. The oven temperature is 220°C and the heating time is 10 minutes. When transferring the etched circuit to the PDMS film, the alignment structure between the circuit and the PDMS film is designed in advance to facilitate subsequent electrode welding.

[0021] Furthermore, in step 5, when using an ultraviolet laser engraving machine to etch the microchannels, the laser parameters used are: number of processes: 30, speed: 300, power: 60%. Too high a total power will cause the microchannels to burn and catch fire, while too low a total power will cause them to fail to etch and break down. Subsequently, after embedding the thermoelectric arm into the hole, an injection agent is used to inject AlN-doped PDMS into the gap between the thermoelectric arm and the hole.

[0022] Further, in step 6, during soldering, a PI film of the same size as the thermoelectric microchannel is first cut, and then the electrode holes of the thermoelectric arm are etched out using an ultraviolet laser engraving machine to obtain a mask. The mask is then overlapped with the upper and lower layer circuits. After applying a layer of solder paste to the mask, the mask is lifted, leaving the required solder paste on the electrodes. Finally, the thermoelectric arm and the film of the transfer circuit are aligned and overlapped, and then placed on an oven for heating. The oven temperature is 230°C, the heating time is 10 minutes, and the cooling time is 30 minutes. Soldering is completed after the oven temperature drops below 100°C. In step 6, the upper and lower layers are encapsulated by covering the electrodes with an uncured AlN-doped PDMS film, which is then placed on an oven for heating at 120°C for 15 minutes. After the silicone has cured, it is removed.

[0023] Furthermore, different molds were used to fabricate the lower and upper layers of the flexible substrate; the fluid channel of the prepared lower flexible substrate was 1 mm high, the fluid width was 1 mm, and the bottom film thickness was 0.2 mm; the bottom film of the upper substrate was 0.3 mm, and the overall microchannel thickness was 1.5 mm.

[0024] Flexible water-cooled microchannel fabrication process, embedded thermoelectric arm integration process, stretchable device shape design, multi-device collaboration

[0025] The mechanism of this invention is as follows: Utilizing a flexible water-cooled microchannel fabrication process significantly improves the heat dissipation performance of thermoelectric devices, eliminating the need for complex heat dissipation mechanisms and greatly enhancing their cooling performance. Employing an embedded thermoelectric arm integration process enables miniaturization and integration of thermoelectric devices, while the embedded thermoelectric arm allows for better contact with the microfluidic fluid, improving thermal conductivity. Through the design of a stretchable device shape, stress is released via a serpentine design, and a hexagonal design balances the fluidity and heat transfer performance of the microfluidic fluid, resulting in a structure that enhances the device's stretchability. A multi-device collaborative process allows multiple devices to be used in tandem, forming a thermoelectric device array from a single device, offering better application prospects.

[0026] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0027] This invention provides a method for fabricating a flexible and stretchable thermoelectric device with integrated microchannel water cooling, which greatly improves the performance of the fabricated wearable flexible cooling device. It is lightweight and has good stretchability. Furthermore, the process of integrating microchannels and embedded thermoelectric arms greatly reduces the overall device size. The stretchable shape design improves the stretchability of the device and has the ability to work in tandem with multiple devices. This fabrication method is widely applicable to flexible wearable devices. Attached Figure Description

[0028] Figure 1 This is a diagram of the flexible water-cooled microchannel structure in Example 1.

[0029] Figure 2 This is a diagram of the embedded structure in Example 1.

[0030] Figure 3 The structural diagram of the flexible embedded stretchable thermoelectric device with integrated microchannel water cooling is shown in the figure.

[0031] Figure 4 This is a comparison chart of the cooling performance of water-filled and water-free systems when a current of 0.3A is applied in Comparative Example 1.

[0032] Figure 5 The diagram shows the cooling performance of water when a current of 0.3A-0.5A is applied, as shown in Comparative Example 1.

[0033] Figure 6 The diagram shows the cooling performance of water when a current of 0.5-1A is applied in Comparative Example 1. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0035] Example 1

[0036] Step 1. Microchannel mold printing is performed using 3D printing. The specific implementation plan is as follows: a complementary mold pattern of the microchannel is designed using 3D modeling software, and then printed using a photopolymerization printer. Rigid photosensitive resin is used as the printing consumable. After the mold is printed, it is sprayed and wiped with 75% alcohol. After wiping, the mold is ultrasonically cleaned in 75% alcohol for 10 minutes, then placed in a 60°C oven for 48 hours. Finally, the mold is placed in a UV curing machine for 2 hours to cure the mold, thus obtaining the microchannel infusion mold.

[0037] Step 2. Remove the mold prepared in Step 1. Mix PDMS, AlN, and curing agent in a ratio of 10:4:1, and vacuum the mixture for 30 minutes to remove air bubbles. Then, pour the silicone into the mold and vacuum it again for 30 minutes. This step removes air bubbles generated during pouring and makes the silicone adhere better to the mold. Finally, place the mold in a 60°C oven to cure for 24 hours to obtain microchannel A.

[0038] Step 3. After uniformly coating the silicone obtained in Step 2 onto the glass slide of the spray casting and demolding machine, spin coating is performed using a spin coater at a speed of 500 r / min for 2 min to prepare a PDMS film, which is microchannel B. Microchannel A and microchannel B are then aligned and assembled. During curing, the assembly is placed on an oven rack at 150°C for 10 min. The final microfluidic channel is as follows. Figure 1 As shown.

[0039] Step 4. Place the silicone obtained in Step 2 on an oven at 220°C and heat for 5 minutes to obtain a cured PDMS film. Then, attach the copper foil with polyimide to the water-soluble adhesive tape and use a UV laser engraving machine to etch out the required serpentine circuit and thermoelectric arm electrode. The serpentine circuit is about 0.2 mm wide and the thermoelectric arm electrode is 1.2 mm * 1.2 mm in size. Then, align and transfer the etched circuit onto the PDMS film and place it on an oven at 220°C for 10 minutes.

[0040] Step 5. The microfluidic channels obtained in Step 3 are subjected to UV etching. Holes are etched according to the electrode arrangement of the thermoelectric devices and the serpentine arrangement of the microchannels. The hole arrangement is consistent with the electrodes of the thermoelectric arms. The laser parameters used are: number of processes: 30, speed: 300, power: 60%. Then, the P-type and N-type thermoelectric arms are each embedded halfway into the holes. Finally, uncured AlN-doped PDMS is used with a syringe to fill the gaps between the thermoelectric arms and the microchannel holes, ultimately obtaining a fixed embedded thermoelectric arm structure. Figure 2 As shown.

[0041] Step 6. The upper and lower circuit layers of the thermoelectric device prepared in Step 4 are soldered to the thermoelectric arm through a mask. Specifically, a PI film of the same size as the thermoelectric microchannel is cut first, and then the electrode holes of the thermoelectric arm are etched out using an ultraviolet laser engraving machine to obtain a mask. The mask is overlapped with the upper and lower circuit layers. After applying a layer of solder paste to the mask, the mask is lifted, leaving the required solder paste on the electrode. Finally, the electrode and the thermoelectric arm are aligned and assembled, and then placed on an oven for heating. The oven temperature is 230°C, the heating time is 10 minutes, and the cooling time is 30 minutes. Finally, the upper and lower electrodes are encapsulated with an uncured PDMS film.

[0042] Comparative Example 1

[0043] A flexible, stretchable thermoelectric device with integrated microchannel water cooling, prepared according to the steps of Example 1, shows a significant performance improvement when the water flow rate is 120 ml / min. Different currents affect the cooling effect. The design of the microfluidic channel can dissipate heat from the hot end of the thermoelectric arm, significantly improving the cooling performance of the thermoelectric device.

[0044] Water flow improves performance, such as Figure 4 As shown, when a current of 0.3A is applied, the device only cools down by 3.4°C when no water is flowing through it, and the device experiences a temperature rise even when the power is on, making it unable to cool down stably. When a current of 0.3A is applied, the device can cool down by 7.7°C when water is flowing through it, and the cooling is stable, showing a significant performance improvement compared to traditional devices.

[0045] The cooling performance of the device under different currents is as follows: Figure 5 , Figure 6 As shown, the device exhibits different cooling performance when supplied with 0.3A-1A. Compared to traditional devices that cannot achieve stable cooling at 0.3A, the device designed in this invention can achieve stable cooling at 0.5A-1A, with a maximum cooling of 10°C. Compared to traditional devices that can only achieve unstable cooling of 3.4°C, the performance of the flexible device designed in this invention is improved by nearly 3 times.

[0046] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All disclosed features, or steps in all methods or processes, may be combined in any way except for mutually exclusive features and / or steps.

Claims

1. A flexible, embedded, stretchable thermoelectric device with integrated microchannel water cooling, the device comprising: The system comprises a flexible substrate, an N-type thermoelectric arm, and a P-type thermoelectric arm. The flexible substrate has microchannels, including an input channel, a heat exchange channel, and an output channel. The heat exchange channel consists of multiple layers from the outside in, each layer being a regular hexagon. However, the flow path along each side of the hexagon is a reciprocating "S" shape. When a virtual straight line is drawn from the center of the hexagon, the "S" shapes of adjacent heat exchange channels on the virtual straight line have opposite bending directions. The input and output channels are directly connected through a pair of opposite diagonals of the hexagon, with the center point of the hexagon serving as the dividing point; one side is the input channel, and the other is the output channel. The input channel, starting from the inlet, passes through each heat exchange channel layer. The width of the downstream flow channel decreases, and the width of the output flow channel increases after each heat exchange flow channel from the port connecting to the input flow channel. N-type thermoelectric arms and P-type thermoelectric arms are arranged alternately on both sides of the heat exchange flow channel. The N-type thermoelectric arms and P-type thermoelectric arms are cylindrical, with half of them embedded in the flexible substrate. The positions of the N-type thermoelectric arms and P-type thermoelectric arms correspond to the "S"-shaped recesses of the heat exchange flow channel. Metal patches are provided at the bottom and top of the N-type thermoelectric arms and P-type thermoelectric arms. The bottom metal patches or top metal patches of adjacent N-type thermoelectric arms and P-type thermoelectric arms are connected by "S"-shaped electrodes, ultimately realizing that all N-type thermoelectric arms and P-type thermoelectric arms are connected in series at intervals.

2. The flexible embedded stretchable thermoelectric device with integrated microchannel water cooling as described in claim 1, characterized in that, The connection method of the N-type thermoelectric arm and the P-type thermoelectric arm is as follows: first, the thermoelectric arms in each loop are connected in series, and then the loops are connected in series.

3. The flexible embedded stretchable thermoelectric device with integrated microchannel water cooling as described in claim 1, characterized in that, The flexible substrate is made of a mixture of PDMS, AlN and curing agent in a ratio of 10:4:1, and the S-shaped electrode is made of copper foil with a total thickness not exceeding 50 μm.

4. The method for fabricating a flexible embedded stretchable thermoelectric device with integrated microchannel water cooling as described in claim 1, the method comprising: Step 1. Design a microchannel complementary mold using 3D modeling software and 3D print it. After printing, perform mold pretreatment. Divide the flexible substrate into a lower layer and an upper layer. The lower and upper layers have the same structure. Use the same mold for preparation. The specific steps are as follows: wipe the mold with alcohol to remove a large amount of residual resin, soak it in alcohol and use ultrasonic cleaning to remove residual resin, then place the mold in an oven to bake, and finally use ultraviolet light to cure to obtain a pourable mold. Step 2. Mix PDMS, AlN and curing agent to obtain AlN-doped PDMS. Then pour the obtained AlN-doped PDMS into the mold obtained in Step 1 and place it in an oven to cure. After curing, the AlN-doped PDMS is removed from the mold to obtain half of the substrate. Step 3. The AlN-doped PDMS from Step 2 is uniformly coated onto a glass slide coated with a release agent. After spin coating on a spin coater, an uncured AlN-doped PDMS film is obtained. This film is used to bond two substrates prepared in Step 2. After the film cures, the desired flexible substrate with microchannels is obtained. Step 4. Using the same method as in Step 3, fabricate an AlN-doped PDMS film. Then, place the film on an oven and heat it to obtain a cured AlN-doped PDMS film. Adhere the copper foil with polyimide to the water-soluble adhesive tape, and then fix the water-soluble adhesive tape to the glass slide. Use an ultraviolet laser engraving machine to etch out the serpentine circuit and thermoelectric arm electrodes required for the device. Then, transfer the etched circuit onto the prepared PDMS film and heat it. After washing off the water-soluble adhesive, the printed circuit PDMS film is obtained. Step 5. Use an ultraviolet laser engraving machine to etch the flexible substrate obtained in step 3. Design the etched holes according to the electrode arrangement of the thermoelectric device and the shape of the microchannel. Use an ultraviolet laser engraving machine to penetrate the flexible substrate. Then, embed the N-type thermoelectric arm and the P-type thermoelectric arm at intervals of 1 / 2 into the holes respectively. Use the uncured AlN-doped PDMS obtained in step 3 to fill the gap between the thermoelectric arm and the microchannel hole. Step 6. Two PDMS films of printed circuit obtained in Step 4 are respectively applied to the bottom and top of the N-type thermoelectric arm and the P-type thermoelectric arm, with the bottom being the part embedded in the substrate; then the circuit is soldered to the thermoelectric arm, and after soldering, the circuit is encapsulated using the AlN-doped PDMS obtained in Step 2.

5. The method for fabricating a flexible embedded stretchable thermoelectric device with integrated microchannel water cooling as described in claim 4, wherein the packaging method for the top circuit in step 6 is as follows: the top of the device after welding the circuit is attached to the glass substrate with hydrosol, and then AlN-doped PDMS is used to seal the side of the thermoelectric arm and the PDMS film of the printed circuit on the top using a spin coating process.

6. The method for fabricating a flexible embedded stretchable thermoelectric device with integrated microchannel water cooling as described in claim 4, wherein the resin material used for 3D printing in step 1 is a rigid photocurable resin, the alcohol concentration used for cleaning residual resin is 75%, and the oven temperature is 60°C; in step 2, after obtaining AlN-doped PDMS, it needs to be placed in a vacuum machine for 30 minutes to remove air bubbles, and after the silicone is poured into the mold, it also needs to be placed in a vacuum machine for 30 minutes to remove residual air bubbles, which also makes the silicone adhere better to the mold, and then placed in an oven at 60°C for 24 hours to cure.

7. The method for fabricating a flexible embedded stretchable thermoelectric device with integrated microchannel water cooling as described in claim 4, wherein in step 3, the glass sheet after spraying the release agent needs to be placed on an oven at 220°C and heated for 5 minutes, and the spin coating machine is used to spin coat at 500 r / min for 2 minutes. After that, it needs to be vacuumed and combined with microchannel A. When the combination is cured, it is placed on an oven at 150°C and heated for 10 minutes. The overall thickness of the copper foil used to bond the polyimide in step 4 does not exceed 50 μm. The electrode base of the thermoelectric arm is designed to be 1.2 mm * 1.2 mm in size, and the "S"-shaped circuit line width is 0.2 mm. The oven temperature is 220°C and the heating time is 10 minutes. When transferring the etched circuit to the PDMS film, the alignment structure between the circuit and the PDMS film is designed in advance to facilitate subsequent electrode welding.

8. In the method for fabricating a flexible embedded stretchable thermoelectric device with integrated microchannel water cooling as described in claim 4, in step 5, when etching the microchannel using an ultraviolet laser engraving machine, the laser parameters are: number of processes: 30, speed: 300, power: 60%. If the total power is too high, the microchannel will burn and catch fire; if the total power is too low, it will fail to etch and break down. After embedding the thermoelectric arm in the hole, an injection agent is used to inject AlN-doped PDMS into the gap between the thermoelectric arm and the hole.

9. In the method for fabricating a flexible embedded stretchable thermoelectric device with integrated microchannel water cooling as described in claim 4, during welding in step 6, a PI film of the same size as the thermoelectric microchannel is first cut, and then the electrode holes of the thermoelectric arm are etched out using an ultraviolet laser engraving machine to obtain a mask. The mask is overlapped with the upper and lower layer circuits. After applying a layer of solder paste to the mask, the mask is lifted, leaving the required solder paste on the electrode. Finally, the thermoelectric arm and the film of the transfer circuit are aligned and overlapped, and then placed on an oven for heating. The oven heating temperature is 230°C, the heating time is 10 minutes, and the cooling time is 30 minutes. Welding is completed after the oven temperature drops below 100°C. In step 6, the upper and lower layers are encapsulated by covering the electrodes with an uncured AlN-doped PDMS film, which is placed on an oven for heating at 120°C for 15 minutes. After the silicone has cured, it is removed.

10. The method for fabricating a flexible embedded stretchable thermoelectric device with integrated microchannel water cooling as described in claim 4, wherein different molds are used to fabricate the lower and upper layers of the flexible substrate; the fluid channel of the fabricated lower flexible substrate is 1 mm high, the fluid width is 1 mm, and the bottom film thickness is 0.2 mm; the bottom film of the upper substrate is 0.3 mm, and the overall thickness of the microchannel is 1.5 mm.

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