A flexible composite film for adaptive thermal management and low-temperature waste heat power generation and a preparation method thereof

Abstract

The present invention belongs to the field of thermal management and thermal energy collection, and specifically relates to an adaptive thermal management and low-temperature waste heat power generation flexible composite film and a preparation method thereof. The present invention provides an adaptive thermal management and low-temperature waste heat power generation flexible composite film, comprising a thermal expansion polymer substrate, cellulose paper and at least one group of horizontally arranged and / or stacked p-n thermoelectric film pairs, wherein the p-n thermoelectric film pairs are placed between the thermal expansion polymer substrate and the cellulose paper; each two of the p-n thermoelectric film pairs are connected in series, and each two of the stacked p-n thermoelectric film pairs are partially blocked by a hot-melt diaphragm; the p-n thermoelectric film pairs are composed of an n-type thermoelectric film, a p-type thermoelectric film and a hot-melt diaphragm that partially blocks the p-type thermoelectric film from the n-type thermoelectric film. The power generation flexible composite film of the present invention solves the problem that the existing thermoelectric generator must be provided with hot and cold ends, and can achieve adaptive thermal management and autonomous power generation.

Description

Technical Field

[0001] The present invention belongs to the field of thermal management and thermal energy collection, and specifically relates to an adaptive thermal management and low-temperature waste heat power generation flexible composite film and a preparation method thereof. Background Art

[0002] Heat is ubiquitous in human production activities. Rational design of advanced devices and technologies for heat regulation, collection, conversion, storage and utilization is of great significance for reducing heat accumulation, alleviating energy crises and promoting sustainable development. The thermal management process refers to the regulation and control of the temperature and temperature difference of a specific object by heating or cooling. In many thermal environment fields, including human body temperature, building walls, transportation, electrical housings, etc., the demand for high-performance and intelligent thermal management materials is increasing.

[0003] Existing thermoelectric generators (TEGs) are a promising energy harvesting material that can directly convert low-grade heat into electrical energy, effectively improving the utilization efficiency of low-temperature waste heat. However, existing TEGs have a certain thickness, are rigid and brittle, and have complex and inefficient out-of-plane configurations that limit their freedom or scalability. They cannot adapt to the complex geometric shapes of various devices and conform to the surface properties of materials. In addition, TEGs are required to have long TE legs or additional cooling systems to achieve better power generation effects. However, currently two-dimensional thermoelectric materials all require an insulating membrane to block the heat source to form hot and cold ends, which further increases the thickness and weight of self-powered components.

[0004] Therefore, how to obtain a flexible and lightweight thermoelectric composite material that integrates thermal management and thermoelectric functions to further broaden its application scenarios has become one of the focuses of widespread attention among researchers in this field. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a flexible composite film for adaptive thermal management and low-temperature waste heat power generation and a preparation method thereof, a temperature difference power generation component and a preparation method thereof, and in particular to a flexible composite film for adaptive thermal management and low-temperature waste heat power generation. The packaging material of the adaptive thermal management and low-temperature waste heat power generation flexible composite film provided by the present invention has an asymmetric thermal expansion coefficient, thereby inducing a reversible temperature-responsive deformation, forming a temperature difference at both ends of the power generation flexible composite film, and can achieve adaptive thermal management and autonomous power generation without setting a hot and cold end.

[0006] The present invention provides an adaptive thermal management and low-temperature waste heat power generation flexible composite film, comprising a thermal expansion polymer substrate, cellulose paper and at least one group of horizontally arranged and / or stacked pn thermoelectric film pairs, wherein the pn thermoelectric film pairs are arranged between the thermal expansion polymer substrate and the cellulose paper; every two of the pn thermoelectric film pairs are connected in series, and every two of the stacked pn thermoelectric film pairs are partially blocked by a hot-melt type diaphragm; the pn thermoelectric film pairs are composed of an n-type thermoelectric film, a p-type thermoelectric film and a hot-melt type diaphragm that partially blocks the p-type thermoelectric film from the n-type thermoelectric film.

[0007] Preferably, the power generation flexible composite film includes 1-3 groups of pn thermoelectric film pairs.

[0008] Preferably, the power generation flexible composite film includes a group of pn thermoelectric film pairs.

[0009] The number of pn thermoelectric film pairs will directly affect the thickness and weight of the flexible composite film for power generation, which may limit the usage scenarios of the pn thermoelectric film pairs. Therefore, controlling the number of pn thermoelectric film pairs within a more appropriate range will be more conducive to the application of the flexible composite film for power generation.

[0010] Preferably, one end of the p-type thermoelectric film and the n-type thermoelectric film are bonded together with conductive silver paste, and the rest are blocked by a hot-melt diaphragm.

[0011] Preferably, the heat expandable polymer substrate is at least one of biaxially oriented polypropylene, polyethylene terephthalate, polyethylene, biaxially oriented polypropylene, polyamide resin, and polyvinylidene fluoride; more preferably, the heat expandable polymer substrate is polyethylene terephthalate.

[0012] Preferably, the thickness of the heat expandable polymer substrate is 80-200 μm; more preferably, the thickness of the heat expandable polymer substrate is 150 μm.

[0013] Preferably, the thickness of the cellulose paper is 80-100 μm, more preferably, the thickness of the cellulose paper is 80 μm.

[0014] Preferably, the n-type thermoelectric film is a self-supporting film formed of an n-type material, and the n-type material is selected from at least one of nitrogen-doped single-arm carbon nanotubes, silver selenide, bismuth antimonide, molybdenum carbide and molybdenum carbide-titanium.

[0015] Preferably, the n-type thermoelectric film is prepared according to the following preparation method: the n-type material is dispersed in solvent I, vacuum filtered on a water filter membrane after ultrasonic treatment, and then placed in a blast or vacuum oven, and dried to form an n-type thermoelectric film.

[0016] Preferably, the thickness of the n-type thermoelectric film is 30-50 μm; more preferably, the thickness of the n-type thermoelectric film is 40 μm.

[0017] Preferably, the ultrasonic time is 5 to 10 minutes; the vacuum filtration pressure is 0.9 to 1 MPa; the blast or vacuum oven is set at a temperature of 40 to 60°C, the vacuum degree of the vacuum oven is -0.08 to -0.1 MPa, and the time is 4 to 8 hours; the cold pressing pressure is 10 to 20 MPa, and the time is 10 to 20 minutes.

[0018] Preferably, the solvent I is selected from at least one of water and ethanol, and the mass ratio of the n-type material to the solvent I is 1:1000 to 1:2000.

[0019] Preferably, the p-type thermoelectric film is a self-supporting film formed by cold pressing of a p-type material, and the p-type material is selected from at least one of single-arm carbon nanotubes, poly-3,4-dioxyethylthiophene poly-p-styrene sulfonic acid, antimony telluride, silver antimonide, tin selenide, titanium carbide, and niobium carbide.

[0020] Preferably, the p-type thermoelectric thin film is prepared according to the following preparation method: ultrasonically dispersing the p-type material in solvent II, vacuum filtering it on an organic filter membrane, and drying it in a blast or vacuum oven to form a p-type thermoelectric thin film.

[0021] Preferably, the thickness of the p-type thermoelectric film is 30-50 μm, and more preferably, the thickness of the p-type thermoelectric film is 40 μm.

[0022] Preferably, the ultrasonic time is 5 to 10 minutes; the vacuum filtration pressure is 0.85 to 0.95 MPa; the vacuum oven is set at a temperature of 40 to 60°C, a vacuum degree of -0.08 to -0.1 MPa, and a time of 4 to 8 hours; the cold pressing pressure is 10 to 20 MPa, and the time is 10 to 20 minutes.

[0023] Preferably, the solvent II is selected from at least one of water and ethanol, and the mass ratio of the p-type material to the solvent II is 1:1000 to 1:2000.

[0024] Preferably, the hot-melt diaphragm is an EVA hot-melt diaphragm, and the thickness of the EVA hot-melt diaphragm is 20 to 50 μm. More preferably, the thickness of the EVA hot-melt diaphragm is 40 μm.

[0025] Preferably, the power generation flexible composite film also includes an electrode, which is arranged on a side close to the hot-melt diaphragm, and the electrodes are respectively connected to the p-type thermoelectric film and the n-type thermoelectric film, and the electrodes are selected from one of copper foil, silver foil, platinum foil and gold foil; preferably, the electrode is copper foil.

[0026] Preferably, the thickness of the electrode is 40-80 μm; more preferably, the thickness of the electrode is 80 μm.

[0027] The present invention provides a method for preparing a flexible composite film for adaptive thermal management and low-temperature waste heat power generation, comprising the following steps:

[0028] S1. Cut the p-type thermoelectric film and the n-type thermoelectric film into rectangles of the same size, and cut the EVA hot-melt separator into a rectangle with the same width as the p-type thermoelectric film and the n-type thermoelectric film and slightly smaller length;

[0029] S2, bonding one side of the length direction of the p-type thermoelectric film and the n-type thermoelectric film processed by S1 with a conductive silver paste, and isolating the rest of the film with a hot-melt diaphragm to form a pn thermoelectric film pair;

[0030] S3. The pn thermoelectric film pairs of S2 are stacked and / or arranged horizontally and connected in series, and each two groups of stacked pn thermoelectric film pairs are separated by a hot-melt diaphragm, and then placed between a thermally expandable polymer substrate and cellulose paper, and hot-pressed and packaged to obtain a flexible composite film for adaptive thermal management and low-temperature waste heat power generation.

[0031] Preferably, the temperature of the hot pressing packaging is 90-110° C., the time is 2-10 min, and the pressure is 10-20 MPa.

[0032] The present invention provides a temperature difference power generation component, comprising the above-mentioned power generation flexible composite film.

[0033] The present invention provides a method for preparing a temperature difference power generation component. The temperature difference power generation component can be obtained by sequentially connecting the above-mentioned power generation flexible composite films in series and fixing them on a flexible PET film.

[0034] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0035] 1. During the use of the power generation flexible composite film provided by the present invention, the heat expansion polymer substrate is placed close to the heat source, and the electrode side is fixed at the same time. When the heat source is within a certain temperature range, due to the difference in expansion coefficient, the length elongation of the heat expansion polymer substrate and the two sides of the cellulose paper are inconsistent, the film bends, and the unfixed side is separated from the heat source, forming a temperature difference at both ends of the film, and realizing autonomous power generation. The self-response function of the power generation flexible composite film is reversible and repeatable, so it can spontaneously assist the heat source in dissipating heat, realizing adaptive thermal management and low-temperature temperature difference power generation.

[0036] 2. The power generation flexible composite film of the present invention adopts the assembly method of vertically bridged pn thermoelectric film pairs to increase the number of thermoelectric units per unit area and effectively improve the power generation efficiency per unit area.

[0037] 3. The processing technology of the present invention is simple, and the bonding effect between the components of the composite material is enhanced through the hot pressing composite process, the contact resistance is reduced, and the thermoelectric performance is optimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of the structure of the adaptive thermal management and low-temperature waste heat power generation flexible composite film prepared in Example 1;

[0039] Figure 2 The actual picture of the filter membrane deposited with Ag2Se before and after cold pressing in Example 1;

[0040] Figure 3 A line graph showing the bending angle and voltage changes of the adaptive thermal management and low-temperature waste heat power generation flexible composite film prepared in Example 1 during use when the heat source temperature changes from 40°C to 80°C;

[0041] Figure 4 The actual voltage measurement of the adaptive thermal management and low-temperature waste heat power generation flexible composite film prepared in Example 1 during use when the heat source is 80°C;

[0042] Figure 5 It is a schematic top view of the structure of three pn thermoelectric thin film pairs arranged horizontally and in series in Example 4 of the present invention;

[0043] Figure 6 This is a front view structural schematic diagram of three pn thermoelectric thin film pairs stacked and connected in series in Example 5 of the present invention;

[0044] Figure 7 This is a schematic structural diagram of a thermoelectric power generation component according to Embodiment 6 of the present invention;

[0045] Figure 8 This is an application principle diagram of the temperature difference power generation component of Example 6 of the present invention;

[0046] Among them, 1-p-type thermoelectric film; 2-EVA hot-melt diaphragm; 3-conductive silver paste; 4-n-type thermoelectric film; 5-cellulose paper; 6-thermal expansion polymer substrate; 7-electrode; 8-power generation flexible composite film; 9-pn thermoelectric film pair; 10-PET flexible substrate. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0048] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0049] There is no particular limitation on the purity of all raw materials in the present invention. The present invention preferably uses analytically pure materials or materials with conventional purity in the field of metal-air batteries.

[0050] Example 1

[0051] This embodiment provides a method for preparing a flexible composite film for adaptive thermal management and low-temperature waste heat power generation, and the specific steps are as follows:

[0052] (1) Preparation of p-type thermoelectric film: 15 mg of single-arm carbon nanotubes were ultrasonically dispersed in 30 ml of ethanol for 7 min, and the single-arm carbon nanotubes were filtered onto an organic filter membrane by vacuum filtration at a pressure of 0.9 MPa. The film was then dried in a vacuum oven at 50°C with a vacuum degree of -0.09 MPa to form a p-type thermoelectric film with a thickness of 40 μm.

[0053] (2) Preparation of n-type thermoelectric film: 145 mg of Ag2Se nanowires with a length of 5 to 10 μm were dispersed in 100 ml of deionized water. After ultrasonic treatment for 8 min, the nanowires were vacuum filtered onto a water filter membrane at a pressure of 0.95 MPa. The nanowires were then dried in a vacuum oven at 50°C with a vacuum degree of -0.09 MPa. The dried Ag2Se nanowires and filter membrane were cold pressed at a pressure of 15 MPa for 15 min to form an n-type thermoelectric film with a thickness of 40 μm.

[0054] (3) Preparation of flexible composite films for power generation: The prepared p-type thermoelectric films and n-type thermoelectric films were cut into strips of 12*40 mm in size, and copper electrodes were connected to one side of the two films with conductive silver paste. The films were separated in the middle with a 40 μm thick EVA hot-melt diaphragm, and the side without copper electrodes was directly connected with silver paste to form a pn thermoelectric film pair. Then, the connected pn thermoelectric film pair was placed between a 150 μm thick PET plastic film and an 80 μm thick cellulose paper, and hot-pressed for 5 minutes at 100°C and a pressure of 15 MPa to finally form a 345 μm thick 5-layer composite structure flexible composite film for power generation.

[0055] The schematic diagram of the structure of the flexible composite film for power generation prepared in this embodiment is shown in Figure 1 shown.

[0056] The structural characteristics, temperature response effects and thermoelectric conversion performance of the adaptive thermal management and low-temperature waste heat power generation flexible composite film prepared in this embodiment are as follows:

[0057] The inventors compared the physical pictures of the Ag2Se deposited filter membrane before and after cold pressing in this embodiment, Figure 2 As shown by Figure 2 It can be seen that after cold pressing, the Ag2Se deposited filter membrane presents a metallic luster, from which it is inferred that the contact between the Ag2Se nanowires is closer after cold pressing. The inventors also compared the conductivity of the Ag2Se deposited filter membrane before and after cold pressing, and found that the conductivity increased from 5s / cm to 260s / cm after cold pressing.

[0058] During use of the power generation flexible composite film prepared in this embodiment, the thermal expansion polymer substrate of the power generation flexible composite film is brought into contact with a heat source, and one side with an electrode is fixed on the heat source. When the temperature of the heat source changes from room temperature to 80°C, the bending angle and voltage change of the power generation flexible composite film are shown in the figure. Figure 3 ,Depend on Figure 3 It can be seen that within this temperature range, as the temperature increases, the bending angle of the film gradually increases, and the voltage also continues to increase. In particular, when the heat source is 80°C, the bending angle of the power generation flexible composite film is 19°, and the actual voltage measurement of the power generation flexible composite film is shown in Figure 4 ,Depend on Figure 4 It can be seen that at this temperature, the generated voltage is 3.65mV.

[0059] Example 2

[0060] This embodiment provides a method for preparing a flexible composite film for adaptive thermal management and low-temperature waste heat power generation, and the specific steps are as follows:

[0061] (1) Preparation of p-type thermoelectric film: 15 mg of single-arm carbon nanotubes were ultrasonically dispersed in 30 ml of ethanol for 5 min, and the single-arm carbon nanotubes were filtered onto an organic filter membrane by vacuum filtration at a pressure of 0.85 MPa, and then dried in a vacuum oven at 60° C. with a vacuum degree of −0.08 MPa to form a p-type thermoelectric film with a thickness of 30 μm;

[0062] (2) Preparation of n-type thermoelectric thin film: 140 mg of Ag2Se nanowires with a length of 5 to 10 μm and 5 mg of Ti3C2Tx were dispersed in 100 ml of deionized water, and then vacuum filtered on a water filter membrane after ultrasonic treatment for 10 min. The vacuum filtration pressure was 0.9 PMa, and then dried in a vacuum oven at 60°C. The vacuum degree of the vacuum oven was -0.08 MPa. The dried composite filter membrane was cold pressed at a pressure of 10 MPa for 20 min to form an n-type thermoelectric thin film with a thickness of 30 μm.

[0063] (3) Preparation of flexible composite films for power generation: The above two thermoelectric films were cut into strips of 8*40 mm in size, and copper electrodes were connected on one side of the two films with conductive silver paste. The films were separated in the middle with a 20 μm thick EVA hot-melt diaphragm, and the side without copper electrodes was directly connected with silver paste to form a pn thermoelectric film pair. Then, the connected pn thermoelectric film pair was placed between a PET plastic film with a thickness of 80 μm and a cellulose paper with a thickness of 80 μm, and hot-pressed for 10 minutes at 90°C and a pressure of 20 MPa to finally form a 5-layer composite structure flexible composite film with a thickness of 235 μm.

[0064] Example 3

[0065] This embodiment provides a method for preparing a flexible composite film for adaptive thermal management and low-temperature waste heat power generation, and the specific steps are as follows:

[0066] (1) Preparation of p-type thermoelectric film: 20 mg of single-arm carbon nanotubes were ultrasonically dispersed in 30 ml of ethanol for 10 min, and the single-arm carbon nanotubes were filtered onto an organic filter membrane by vacuum filtration at a pressure of 1 MPa. The membrane was dried in a vacuum oven at 40°C with a vacuum degree of -0.1 MPa to form a p-type thermoelectric film with a thickness of 50 μm.

[0067] (2) Preparation of n-type thermoelectric film: 20 mg of single-arm carbon nanotubes modified with polyethyleneimine were dispersed in 30 ml of ethanol, and after ultrasonic treatment for 10 min, vacuum filtered on a water filter membrane at a vacuum filtration pressure of 1 MPa, and then placed in a 40°C vacuum oven with a vacuum degree of -0.1 MPa. After drying, a modified single-arm carbon nanotube self-supporting film was formed, forming an n-type thermoelectric film with a thickness of 50 μm;

[0068] (3) Preparation of flexible composite films for power generation: The above two thermoelectric films were cut into strips of 8*40 mm in size, and copper electrodes were connected to one side of the two films with conductive silver paste. The films were separated in the middle with a 50 μm thick EVA hot-melt diaphragm, and the side without copper electrodes was directly connected with silver paste to form a pn thermoelectric film pair. Then, the connected pn thermoelectric film pair was placed between a 160 μm thick PET plastic film and a 100 μm thick cellulose paper, and hot-pressed for 2 minutes at 110°C and a pressure of 10 MPa to finally form a 405 μm thick 5-layer composite structure flexible composite film for power generation.

[0069] Example 4

[0070] This embodiment provides a method for preparing a flexible composite film for adaptive thermal management and low-temperature waste heat power generation, and the specific steps are as follows:

[0071] (1) Preparation of p-type thermoelectric film: 15 mg of single-arm carbon nanotubes were ultrasonically dispersed in 30 ml of ethanol for 7 min, and the single-arm carbon nanotubes were filtered onto an organic filter membrane by vacuum filtration at a pressure of 0.9 MPa. The film was then dried in a vacuum oven at 50°C with a vacuum degree of -0.09 MPa to form a p-type thermoelectric film with a thickness of 40 μm.

[0072] (2) Preparation of n-type thermoelectric film: 145 mg of Ag2Se nanowires with a length of 5 to 10 μm were dispersed in 100 ml of deionized water. After ultrasonic treatment for 8 min, the nanowires were vacuum filtered onto a water filter membrane at a pressure of 0.95 MPa. The nanowires were then dried in a vacuum oven at 50°C with a vacuum degree of -0.09 MPa. The dried Ag2Se nanowires and filter membrane were cold pressed at a pressure of 15 MPa for 15 min to form an n-type thermoelectric film with a thickness of 40 μm.

[0073] (3) Preparation of flexible composite films for power generation: The prepared p-type thermoelectric film and n-type thermoelectric film were cut into strips of 12*40 mm in size, and copper electrodes were connected to one side of the two films with conductive silver paste. The films were separated by a 40 μm thick EVA hot-melt diaphragm, and the side without copper electrodes was directly connected with silver paste to form a pn thermoelectric film pair. Three pn thermoelectric film pairs were arranged horizontally and connected in series, such as Figure 5 As shown, the above-mentioned series-connected pn thermoelectric film pair is then placed between a PET plastic film with a thickness of 150 μm and a cellulose paper with a thickness of 80 μm, and is hot-pressed for 5 minutes at 100°C and a pressure of 15 MPa to finally form a 347 μm thick 5-layer composite structure flexible composite film for power generation.

[0074] Example 5

[0075] This embodiment provides a method for preparing a flexible composite film for adaptive thermal management and low-temperature waste heat power generation, and the specific steps are as follows:

[0076] (1) Preparation of p-type thermoelectric film: 15 mg of single-arm carbon nanotubes were ultrasonically dispersed in 30 ml of ethanol for 7 min, and the single-arm carbon nanotubes were filtered onto an organic filter membrane by vacuum filtration at a pressure of 0.9 MPa. The film was then dried in a vacuum oven at 50°C with a vacuum degree of -0.09 MPa to form a p-type thermoelectric film with a thickness of 40 μm.

[0077] (2) Preparation of n-type thermoelectric film: 145 mg of Ag2Se nanowires with a length of 5 to 10 μm were dispersed in 100 ml of deionized water. After ultrasonic treatment for 8 min, the nanowires were vacuum filtered onto a water filter membrane at a pressure of 0.95 MPa. The nanowires were then dried in a vacuum oven at 50°C with a vacuum degree of -0.09 MPa. The dried Ag2Se nanowires and filter membrane were cold pressed at a pressure of 15 MPa for 15 min to form an n-type thermoelectric film with a thickness of 40 μm.

[0078] (3) Preparation of flexible composite films for power generation: The prepared p-type thermoelectric films and n-type thermoelectric films were cut into strips of 12*40 mm in size, and copper electrodes were connected on one side of the two films with conductive silver paste. The films were separated in the middle with a 40 μm thick EVA hot-melt diaphragm, and the side without copper electrodes was directly connected with silver paste to form a pn thermoelectric film pair. Three pn thermoelectric film pairs were stacked and connected in series, and each pair of pn thermoelectric film pairs was separated by a 40 μm thick EVA hot-melt diaphragm, such as Figure 6 As shown, the above-mentioned series-connected pn thermoelectric film pair is then placed between a PET plastic film with a thickness of 150 μm and a cellulose paper with a thickness of 80 μm, and is hot-pressed for 5 minutes at 100°C and a pressure of 15 MPa to finally form a 5-layer composite structure with a thickness of 580 μm for power generation. Flexible composite film.

[0079] Example 6

[0080] This embodiment provides a method for preparing a temperature difference power generation component, the steps are as follows:

[0081] The power generation flexible composite film prepared in Example 1 was connected in series as a power generation unit, and the n-terminal electrodes and p-terminal electrodes of 12 power generation flexible composite film units were sequentially connected and fixed on the flexible PET film with through holes to prepare a temperature difference power generation component. The structural schematic diagram is shown in Figure 7 shown.

[0082] The above-mentioned temperature difference power generation component has good adaptive thermal management. After heating, one end of the power generation flexible composite film unit on the heating component is lifted up, and it can be ventilated and dissipated through the through hole. The application principle diagram is shown in Figure 8 shown.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A flexible composite film for adaptive thermal management and low-temperature waste heat power generation, characterized in that: The invention comprises a heat-expandable polymer substrate, cellulose paper and at least one group of horizontally arranged and / or stacked pn thermoelectric film pairs, wherein the pn thermoelectric film pairs are arranged between the heat-expandable polymer substrate and the cellulose paper; every two pn thermoelectric film pairs are connected in series, and every two stacked pn thermoelectric film pairs are partially blocked by a hot-melt type diaphragm; the pn thermoelectric film pairs are composed of an n-type thermoelectric film, a p-type thermoelectric film and a hot-melt type diaphragm that partially blocks the p-type thermoelectric film from the n-type thermoelectric film; The heat expandable polymer substrate and the cellulose paper have different coefficients of thermal expansion.

2. The adaptive thermal management and low-temperature waste heat power generation flexible composite film according to claim 1, characterized in that: The thermoelectric power generation flexible composite film comprises 1 to 3 groups of pn thermoelectric film pairs.

3. The adaptive thermal management and low-temperature waste heat power generation flexible composite film according to claim 1, characterized in that: One end of the p-type thermoelectric film and the n-type thermoelectric film are bonded by conductive silver paste, and the rest are blocked by a hot-melt diaphragm.

4. The adaptive thermal management and low-temperature waste heat power generation flexible composite film according to any one of claims 1 to 3, characterized in that: The heat-expandable polymer substrate is at least one of polyethylene terephthalate, polyethylene, biaxially oriented polypropylene, polyamide resin, and polyvinylidene fluoride.

5. The adaptive thermal management and low-temperature waste heat power generation flexible composite film according to any one of claims 1 to 3, characterized in that: The n-type thermoelectric film is a self-supporting film formed by an n-type material, and the n-type material is selected from at least one of nitrogen-doped single-arm carbon nanotubes, silver selenide, bismuth antimonide, molybdenum carbide and molybdenum carbide-titanium.

6. The adaptive thermal management and low-temperature waste heat power generation flexible composite film according to any one of claims 1 to 3, characterized in that: The p-type thermoelectric film is a self-supporting film formed of a p-type material, and the p-type material is selected from at least one of single-arm carbon nanotubes, poly 3, 4-dioxyethylthiophene, poly (p-styrene sulfonic acid), antimony telluride, silver antimonide, tin selenide, titanium carbide, and niobium carbide.

7. The adaptive thermal management and low-temperature waste heat power generation flexible composite film according to any one of claims 1 to 3, characterized in that: The thermoelectric power generation flexible composite film also includes an electrode, which is arranged on a side close to the hot-melt diaphragm, and is respectively connected to the p-type thermoelectric film and the n-type thermoelectric film. The electrode is selected from one of copper foil, silver foil, platinum foil and gold foil, and the thickness of the electrode is 40 to 80 μm.

8. The method for preparing the adaptive thermal management and low-temperature waste heat power generation flexible composite film according to any one of claims 1 to 7, characterized in that: The steps include: S1. Cut the p-type thermoelectric film and the n-type thermoelectric film into rectangles of the same size, and cut the hot-melt diaphragm into a rectangle with the same width as the p-type thermoelectric film and the n-type thermoelectric film and slightly smaller length; S2, bonding one side of the length direction of the p-type thermoelectric film and the n-type thermoelectric film processed by S1 with a conductive silver paste, and isolating the rest of the film with a hot-melt diaphragm to form a pn thermoelectric film pair; S3. The pn thermoelectric film pairs of S2 are stacked and / or arranged horizontally and connected in series, and each two groups of stacked pn thermoelectric film pairs are separated by a hot-melt diaphragm, and then placed between a thermally expandable polymer substrate and cellulose paper, and hot-pressed and packaged to obtain a flexible composite film for adaptive thermal management and low-temperature waste heat power generation.

9. A thermoelectric power generation component, characterized in that: The invention comprises the thermal power generation flexible composite film according to any one of claims 1 to 8.

10. A method for preparing a thermoelectric power generation component, characterized in that: The thermoelectric power generation flexible composite film according to any one of claims 1 to 8 is sequentially fixed in series on a flexible PET film to obtain a thermoelectric power generation component.

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