Foldable thermoelectric conversion device

Abstract

The utility model provides a foldable thermoelectric conversion device, which comprises a flexible packaging body, a diaphragm and two laminated structures, and is characterized in that the flexible packaging body is of a sealing structure extending left and right, and the flexible packaging body is filled with electrolyte solution; the diaphragm is arranged in the flexible packaging body, is of a Z-shaped structure on the whole and is provided with two right-angle corners; the two laminated structures are respectively arranged in the two right-angle corners of the diaphragm and comprise an electrode, a bonding layer and a current collector which extend left and right and are sequentially stacked from bottom to top, the bonding layer is used for connecting the electrode and the current collector, and one end, far away from the right-angle corners, of the current collector is horizontally connected with an output plate which penetrates through the flexible packaging body and extends to the outside. The whole device is completely sealed, the unique structure of the device allows the device to be folded from the middle of two laminated structures, and the device is particularly suitable for heat energy conversion of a heat source with a non-planar surface and convenient to transport and carry.

Description

Technical Field

[0001] This utility model relates to the field of low-grade waste heat energy recovery and conversion, specifically a foldable thermoelectric conversion device. Background Technology

[0002] In recent years, fossil fuels have been the most widely used energy source. However, with continuous updates to refining technologies and improvements to equipment, the conversion efficiency of fossil fuels has reached a bottleneck, while the unused portion is dissipated into the atmosphere as low-grade waste heat. In addition, the reserves of low-grade waste heat energy such as ocean thermal energy, solar energy, and geothermal energy in nature are also abundant.

[0003] Since the surface of the heat source that generates low-grade waste heat energy may be non-planar, in order to reduce energy waste during the heat transfer process, the use of flexible thermoelectric conversion devices for the recovery and conversion of low-grade waste heat energy has become the main research direction in this field. Flexible thermoelectric conversion devices have strong adaptability to non-planar heat sources.

[0004] Patent CN215990603U discloses an all-solid-state flexible thermoelectric conversion device. It uses an electrolyte solution to create an all-solid-state electrolyte, then seals the entire device with a soft silicone rubber material. This allows for the recovery and conversion of low-grade heat energy, which can be output as electrical energy and stored for further use. However, this device cannot be folded, making it inconvenient to transport and carry. Utility Model Content

[0005] To address the shortcomings of existing technologies, this invention provides a foldable thermoelectric conversion device. The device is completely sealed, and its unique structure allows it to be folded from the middle of two stacked structures. It is particularly suitable for the conversion of heat energy from heat sources with non-planar surfaces, and is easy to transport and carry.

[0006] To achieve the above objectives, the specific solution adopted by this utility model is as follows:

[0007] A foldable thermoelectric conversion device, comprising:

[0008] A flexible package with a sealed structure extending to the left and right, the flexible package being filled with an electrolyte solution;

[0009] The diaphragm, housed within a flexible encapsulation, has an overall Z-shaped structure with two right-angled corners;

[0010] Two stacked structures are respectively located in the two right-angle corners of the diaphragm, including electrodes, an adhesive layer and a current collector that extend from left to right and are stacked sequentially from bottom to top. The adhesive layer is used to connect the electrodes and the current collector. The end of the current collector away from the right-angle corner is horizontally connected to an output board that extends through the flexible package to the outside.

[0011] Furthermore, the current collector is a rectangular stainless steel foil sheet with a thickness of 0.02 mm.

[0012] Furthermore, the current collector and the output plate are integrally formed.

[0013] Furthermore, the width of the diaphragm is greater than the width of the electrode.

[0014] Furthermore, the electrode is made of flexible hydrophilic carbon material;

[0015] The adhesive layer is made of conductive silver paste;

[0016] The flexible encapsulation body is made of aluminum-plastic film or silicone material;

[0017] The diaphragm is a Celgard 3501 aqueous diaphragm;

[0018] The electrolyte solution was a 0.01 mol / L aqueous solution of potassium chloride with added silver nanoparticles.

[0019] Beneficial effects:

[0020] The thermoelectric conversion device of this utility model includes a sealed flexible package containing a Z-shaped diaphragm. Two sets of stacked structures are respectively located in the two right-angle corners of the diaphragm. This design allows the device to be folded along the middle part of the two stacked structures. After folding, the size of the device is significantly reduced, making it easy to carry and transport. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a thermoelectric conversion device.

[0022] Figure 2 Microscopic morphology images of the nanoporous sponge and electrodes.

[0023] Figure 3 This is a graph showing the change in output voltage of the thermoelectric conversion device over time under a temperature difference of 20°C.

[0024] Figure 4 The graph shows the discharge voltage of the thermoelectric conversion device as a function of time when a 470Ω load resistor is connected at a temperature difference of 20℃.

[0025] Figure 5 The graph shows the discharge current of the thermoelectric conversion device as a function of time when connected to a 470Ω load resistor at a temperature difference of 20℃.

[0026] Diagram markings: 1. Electrode, 2. Adhesive layer, 3. Current collector, 4. Diaphragm, 5. Flexible encapsulation, 6. Electrolyte solution, 7. Output plate. Detailed Implementation

[0027] The technical solution of this utility model will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0028] In the description of this utility model, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this utility model.

[0029] This utility model discloses a foldable thermoelectric conversion device. Please refer to [reference needed]. Figure 1 The device has a symmetrical structure about its center. It includes a flexible sealing body 5, which is a left-right extending sealing structure filled with an electrolyte solution 6. The flexible sealing body 5 contains a Z-shaped diaphragm 4 and two stacked structures located at the two right-angle corners of the diaphragm 4. Each stacked structure includes electrodes 1, an adhesive layer 2, and a current collector 3, which extend left-right and are stacked sequentially from bottom to top. The adhesive layer 2 connects the electrodes 1 and the current collector 3. The end of the current collector 3 furthest from the right-angle corner is horizontally connected to an output plate 7 extending through the flexible sealing body 5 to the outside. It should be noted that one electrode 1 is used as the working electrode, and the other as the reference electrode. For ease of description, the electrode used as the working electrode is called the working electrode, and the electrode used as the reference electrode is called the reference electrode. When there is no need to distinguish between them, they are collectively referred to as electrodes.

[0030] Specifically, electrode 1 is prepared by immersing the lightweight flexible porous material in a prepared graphene water / ethanol dispersion, removing it, and then drying it in a forced-air drying oven at 60°C for 4 hours. This immersion and drying process is repeated three times. The lightweight flexible porous material is a thin, plate-like nanoporous sponge with a relatively small thickness.

[0031] The adhesive layer 2 is made of conductive silver paste.

[0032] The current collector 3 is a stainless steel foil with a thickness of 0.02mm. The stainless steel foil is cut into a rectangle, and a part with a length of about 10mm and a width of about 5mm is reserved on one side of the rectangle as the output plate 7.

[0033] The diaphragm 4 is a Celgard 2325 diaphragm, and its width must be greater than that of electrode 1.

[0034] The flexible encapsulation body 5 is made of soft materials such as aluminum-plastic film or silicone.

[0035] The electrolyte solution 6 is a 0.01 mol / L potassium chloride aqueous solution with added silver nanoparticles, wherein the concentration of the silver nanoparticles is 100 ppm.

[0036] The method for preparing this thermoelectric conversion device is as follows:

[0037] (a) Prepare a single-layer graphene aqueous dispersion with a mass concentration of 3 mg / g. Take 200 mL of the dispersion and mix it thoroughly with 200 mL of ethanol to obtain a graphene aqueous / ethanol dispersion.

[0038] (b) Weigh a 3cm×3cm×3mm nanoporous sponge and soak it in the prepared graphene water / ethanol dispersion for 5 minutes. Then take it out and put it in a forced-air drying oven to dry at 60℃ for 4 hours. Repeat the soaking and drying process three times to obtain electrode 1. Figure 2 The image shows the microstructure of the nanoporous sponge and electrode 1. It can be seen that the treated nanoporous sponge is filled with graphene material. After weighing and calculating again, it can be found that the graphene content in each nanoporous sponge is about 4.3 mg.

[0039] (c) The electrode 1 and the current collector 3 are bonded together by the adhesive layer 2 to form a stacked structure. Then the two stacked structures are placed in the two right-angle corners of the diaphragm 4 respectively, and then placed together in the flexible package 5. After adding the electrolyte solution 6, the package is sealed and the output plate 7 is exposed, thus obtaining the thermoelectric conversion device.

[0040] The thermoelectric coefficient and thermoelectric conversion efficiency of the device prepared in this invention were calculated: the reference electrode was placed at room temperature (25°C), and the working electrode was in contact with a heat source at 45°C. The output voltage of the device under this constant temperature difference was measured with a digital multimeter, and the highest output voltage was approximately 76.44 mV. Figure 3 The thermoelectric coefficient of the computing device is 3.82 mV / ℃, which is much higher than that of ordinary semiconductor thermoelectric generators. After the output voltage reaches its maximum value, a 470 Ω load resistor is connected for discharge. The discharge voltage across the resistor and the discharge current through the resistor are measured as curves over time, as shown below. Figure 4 and Figure 5 As shown. Based on the discharge voltage and discharge current curves, the internal resistance of the thermoelectric conversion device is calculated to be Rin≈450 Ω. Integrating, the output power of the thermoelectric conversion device is Pout=1.83 μW. Based on the thermal conductivity and thickness of the diaphragm 4, current collector 3, electrode 1, and electrolyte solution 6, the input power is calculated to be Pin≈93.74 mW. Therefore, the thermoelectric conversion efficiency of this device is η≈0.0020%, while the thermoelectric conversion efficiency of ordinary thermoelectric conversion devices is less than 0.0015%.

[0041] In this thermoelectric conversion device, both electrodes 1 are first grounded simultaneously to release excess charge. The working electrode is then attached to the surface of a heat source, while the reference electrode is placed in a lower-temperature environment (such as air). Initially, due to the release of excess charge after grounding, the device's output voltage is zero. As time increases, the working electrode absorbs heat from the heat source surface, causing its temperature to rise. The electrolyte solution ions on its surface redistribute, resulting in a change in the surface potential of the working electrode. Meanwhile, the temperature of the reference electrode, placed in air, remains unchanged, and its surface potential remains constant. Ultimately, a potential difference is formed between the working and reference electrodes, which becomes the device's output voltage. As the temperature of the working electrode continues to rise, the device's output voltage continues to increase. When connected to a circuit, the device's potential is released, converting thermal energy into electrical energy.

[0042] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model in any way. All equivalent modifications or alterations made based on the essence of this utility model should be covered within the protection scope of this utility model.

Claims

1. A foldable thermoelectric conversion device, characterized in that, include: A flexible package with a sealed structure extending to the left and right, the flexible package being filled with an electrolyte solution; The diaphragm, housed within a flexible encapsulation, has an overall Z-shaped structure with two right-angled corners; Two stacked structures are respectively located in the two right-angle corners of the diaphragm, including electrodes, an adhesive layer and a current collector that extend from left to right and are stacked sequentially from bottom to top. The adhesive layer is used to connect the electrodes and the current collector. The end of the current collector away from the right-angle corner is horizontally connected to an output board that extends through the flexible package to the outside.

2. The foldable thermoelectric conversion device according to claim 1, characterized in that, The current collector is a rectangular stainless steel foil sheet with a thickness of 0.02 mm.

3. The foldable thermoelectric conversion device according to claim 1, characterized in that, The current collector and the output plate are integrally formed.

4. The foldable thermoelectric conversion device according to claim 1, characterized in that, The width of the diaphragm is greater than the width of the electrode.

5. A foldable thermoelectric conversion device according to claim 1, characterized in that, The electrode is made of flexible hydrophilic carbon material; The adhesive layer is made of conductive silver paste; The flexible encapsulation body is made of aluminum-plastic film or silicone material; The diaphragm is a Celgard 3501 aqueous diaphragm; The electrolyte solution was a 0.01 mol / L aqueous solution of potassium chloride with added silver nanoparticles.

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