A wearable thermoelectric bracelet and preparation method thereof

Abstract

The present invention discloses a wearable thermoelectric bracelet and a preparation method thereof. The thermoelectric bracelet is formed by arranging P-type and N-type thermoelectric materials in a specific manner and connecting them through silver glue. The thermoelectric bracelet uses flexible fiber paper as a substrate, uniformly applies P and N-type thermoelectric materials on a flexible substrate, bends to form a 3D ring structure, and uses soft, low thermal conductivity, and high fluffiness cotton material as a heat-insulating filler. When worn on the wrist, it can achieve power generation perpendicular to the temperature difference direction of the human body to the greatest extent. The 3D structure thermoelectric bracelet designed by the present invention can overcome the problem that the currently common two-dimensional structure thermoelectric devices can only collect heat within the plane and cannot match the heat flow direction of the human body and the environment. This bracelet is not only simple to operate, low cost, clean, safe, and has no moving parts, but also has a large temperature difference utilization rate and high wearing comfort. It has a high application prospect in the wearable field and will greatly promote the practical application of thermoelectric devices in the self-driven energy supply of wearable devices.

Description

Technical Field

[0001] The present invention relates to the field of wearable thermoelectric devices, and in particular to a wearable thermoelectric bracelet and a preparation method thereof. Background Art

[0002] With the development of wearable electronic devices, they have shown broad application prospects in the fields of vital signs monitoring, human-computer interaction, etc., and have developed rapidly. The issue of how to power them has gradually attracted people's attention. Most wearable devices are still powered by batteries, which makes them subject to frequent battery charging, replacement and pollution. This urgently requires the development of self-powered technology to replace traditional rechargeable batteries to meet their technical needs for miniaturization, high density, green environmental protection, high stability and reliability. It is an effective idea to directly obtain energy from the environment or the human body to power electronic devices and construct a self-driven energy system.

[0003] Thermoelectric materials, also known as thermoelectric materials, are environmentally friendly functional materials that achieve direct conversion between heat and electrical energy through the transport of carriers (holes or electrons) inside solids. Human activities and metabolism will continuously generate heat, causing a certain temperature difference between the skin and the external environment. Thermoelectric materials are made into thermoelectric devices through specific means. This part of the heat energy can be converted into electrical energy through the thermoelectric conversion of thermoelectric materials, which can provide a stable and reliable source of electricity for wearable self-driving systems. Thermoelectric devices are carriers for realizing the energy conversion function of thermoelectric materials, usually consisting of electrodes, thermoelectric materials and substrates. In recent years, in addition to traditional inorganic semiconductor thermoelectric materials, conductive polymer materials have been favored by many well-known research institutions and research groups at home and abroad as a potential thermoelectric material due to their rich raw materials, light weight, easy processing, corrosion resistance, low thermal conductivity and other advantages, and have made great research progress in the past few years. Poly(3,4-ethylenedioxythiophene) (PEDOT) and PEDOT:PSS aqueous solution formed by doping with poly(vinyl phenylsulfonate) (PSS) are the most studied polymer thermoelectric materials with the most outstanding performance. Their electrical conductivity can reach up to 10 3 S / cm, thermal conductivity is only about 0.2W / mK, and the water dispersibility of PEDOT:PSS makes it possible to realize the large-scale preparation of thermoelectric devices through printing and other technologies. In addition, in order to increase the output power per unit area of ​​the device, thermoelectric devices are composed of P and N type thermoelectric arms alternately connected in series and in parallel, but the current N type organic thermoelectric materials have problems such as poor performance, poor stability, and complex preparation methods.

[0004] Although the thermoelectric figure of merit of thermoelectric materials theoretically determines the maximum efficiency of the device, factors such as device structure and interface properties directly affect the actual energy conversion efficiency, power density, stability and other properties of the device. Typical inorganic thermoelectric devices have a π-type structure. When there is a temperature difference between the two ends of the device, the holes and electrons of the P-type and N-type materials diffuse from the hot end to the cold end, respectively, and generate thermoelectric potential through the Seebeck effect, thereby achieving the effect of temperature difference power generation. However, the common two-dimensional structure organic thermoelectric devices currently have the problem of only collecting heat within the plane and cannot match the heat flow direction between the human body and the environment. They cannot efficiently utilize the thermoelectricity released by the human body, which to a certain extent limits the development of thermoelectric devices.

[0005] It should be noted that the information disclosed in the above background technology section is only used for understanding the background of the present application, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned background technology and provide a wearable thermoelectric bracelet and a preparation method thereof to solve the problem that the currently common two-dimensional thermoelectric devices can only collect heat within the plane and cannot match the heat flow direction of the human body and the environment.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A wearable thermoelectric bracelet with flexible fiber paper as a substrate, thermal insulation cotton as a thermal insulation material, P-type thermoelectric materials and N-type thermoelectric materials arranged in an array in two rows staggered and one-to-one correspondence, parallel and alternately arranged in each row, coated on the substrate, and conductively connected in sequence, and bent as a whole to form a 3D ring structure.

[0009] In some embodiments, the N-type thermoelectric material is at least one of nitrogen-doped multi-walled carbon nanotubes, bismuth telluride, and nitrogen-doped graphene, and 5-15 wt % of polyurethane is added to improve its film-forming property.

[0010] The N-type thermoelectric material contains dispersant hexadecyltrimethylammonium bromide.

[0011] The substrate is at least one of the following materials: flexible fiber paper with high air permeability and high toughness, natural fiber and its products, chemical fiber and its products.

[0012] The heat insulating cotton is made of light, soft, and highly fluffy PP cotton or fiber products with a fineness of 3-18.

[0013] The thickness of the thermal insulation material is 0.3-1 cm.

[0014] The wearable thermoelectric bracelet is used to collect energy and generate electricity along the temperature difference direction between human skin and the external environment.

[0015] A method for preparing a wearable thermoelectric bracelet, the method comprising the following steps:

[0016] S1, adding 0.05-0.2g of N-type thermoelectric material, 3-10wt% of dispersant hexadecyltrimethylammonium bromide and 5-15wt% of polyurethane into 5-20ml of solvent, ultrasonically stirring and preparing N-type coating;

[0017] S2, adding 5V% - 10V% dimethyl sulfoxide to 2-10ml of P-type thermoelectric material and stirring to prepare P-type coating;

[0018] S3, coating the P-type coating and the N-type coating in parallel arrays in two columns on the flexible substrate, one column starting with the P-type coating and the other starting with the N-type coating, the P and N-type coatings in the two columns correspond to each other in turn, and the P and N-type coatings in each column are arranged alternately, and then the P and N-type coatings are connected end to end with a conductive material in the following manner: connecting the P and N-type coatings corresponding to each other in the side-by-side arrangement, and connecting the adjacent rows end to end in turn, so as to form an electrical series path;

[0019] S4. Fold the substrate coated with thermoelectric material along the center line of the middle silver-coated area and join the edges to form a hollow strip; fill the hollow part with insulation material, then bend and join the ends into a ring to form a 3D ring structure to obtain a wearable thermoelectric bracelet.

[0020] In step S1, the N-type material is one of nitrogen-doped multi-walled carbon nanotubes, bismuth telluride, and nitrogen-doped graphene, which is dispersed in an aqueous solution to form a slurry, and its film-forming property is improved by adding 5-15wt% of polyurethane.

[0021] In step S1, the concentration of nitrogen-doped multi-walled carbon nanotubes in the N-type coating is in the range of 5-15 mg / mL.

[0022] In step S2, the P-type material used is a commercial PEDOT:PSS aqueous dispersion, and its conductivity is increased by doping 5-10V% of dimethyl sulfoxide.

[0023] In step S3, the substrate used is flexible fiber paper or natural fiber and its products or chemical fiber and its products.

[0024] In step S4, the thermal insulation cotton is made of PP cotton or fiber products.

[0025] In step S4, the thickness of the thermal insulation material is 0.3-1 cm.

[0026] In step S4, a brush combined with a mask is used to apply the prepared P and N type thermoelectric coatings in a parallel and alternating array on the flexible substrate.

[0027] In step S4, the total mass of the bracelet is 3-5g, and the density is 0.053g / cm 3 about.

[0028] The present invention has the following beneficial effects:

[0029] The wearable thermoelectric bracelet provided by the present invention adopts a three-dimensional structural arrangement. Compared with traditional planar arrangement devices, the working environment is no longer limited to a flat heat source. It can better match the heat flow direction perpendicular to the human body and the environment, effectively improve the temperature difference utilization rate, and has no moving parts, good flexibility, easy to wear and high comfort.

[0030] In some embodiments, the preparation method of the wearable thermoelectric bracelet is simple, has low manufacturing cost, good performance, is environmentally friendly, safe, and sustainable.

[0031] In some embodiments, the wearable thermoelectric bracelet uses highly flexible, low thermal conductivity, and lightweight PP cotton as a thermal insulation filler, which further improves the thermal energy utilization rate and increases the temperature difference power generation efficiency without affecting the wearability and comfort of the bracelet.

[0032] In other embodiments, the bracelet can be worn on the wrist to achieve power generation perpendicular to the temperature difference of the human body to the greatest extent, has high application prospects in the wearable field, and will greatly promote the practical application of thermoelectric devices in the self-driven energy supply of wearable devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the plane layout of the PN type structure of the wearable thermoelectric bracelet;

[0034] Figure 2 This is a physical diagram of the PN-type structure plane layout of the wearable thermoelectric bracelet;

[0035] Figure 3 This is a physical expansion diagram of the wearable thermoelectric bracelet;

[0036] Figure 4 A schematic diagram of a wearable thermoelectric bracelet worn on a wrist;

[0037] Figure 5 This is a voltage output performance test diagram of the wearable thermoelectric bracelet;

[0038] Figure 6 Infrared temperature measurement diagram of the wearable thermoelectric bracelet. DETAILED DESCRIPTION

[0039] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope and application of the present invention.

[0040] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for fixing as well as for coupling or communication.

[0041] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0042] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0043] The present invention utilizes temperature difference power generation technology combined with structural optimization of thermoelectric devices, so that the thermoelectric devices match the heat flow direction perpendicular to the human body and the environment as much as possible, and maximizes the use of the temperature difference of the human body, so as to achieve the purpose of using the temperature difference between the human body temperature and the surrounding environment to generate electricity; in the present invention, nitrogen-doped carbon nanotubes are selected as N-type materials, and their film-forming properties are improved by adding dispersants and polyurethanes, which well solves the existing problems of poor performance, poor stability, and complex preparation methods of N-type organic materials.

[0044] The inventive concept of the present invention is as follows: one end of the silver glue connection (the inner side of the bracelet) is attached to the human skin, and the other end is in contact with the outside world, so that a certain temperature difference is formed between the two ends. Under the Seebeck effect, the holes in the P-type thermoelectric material and the electrons in the N-type thermoelectric material will migrate from the high-temperature end to the low-temperature end. Since the P and N-type carriers carry opposite charges, the carriers moving in the same direction will form a continuous current in the closed loop, thereby achieving the purpose of temperature difference power generation. It can be used for sustainable power supply of micro devices and wearable electronic devices.

[0045] like Figure 1-4As shown, an embodiment of the present invention provides a wearable thermoelectric bracelet, including N-type coating 1, P-type coating 2, silver glue 3, flexible fiber paper 4 as a substrate, and thermal insulation cotton as a thermal insulation filler. The N-type coating 1 and the P-type coating 2 are arranged in an array in two rows, one by one, and arranged in parallel in each row. They are coated on the flexible fiber paper 4 and are sequentially conductively connected through the silver glue 3. The whole is bent to form a Figure 4 The 3D ring structure shown is filled with thermal insulation cotton. The bracelet can be used to collect energy and generate electricity along the temperature difference between human skin and the external environment. Specifically, the N-type coating 1 uses nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) or other N-type semiconductor materials, such as bismuth telluride and nitrogen-doped graphene, which can be dispersed in an aqueous solution to form a slurry, and its film-forming property is improved by adding 5-15wt% of polyurethane (WPU); the substrate can also use the following materials: highly breathable and high-toughness flexible fiber paper, natural fibers and their products, chemical fibers and their products. Preferably, the N-type coating 1 also contains a dispersant hexadecyltrimethylammonium bromide; the thermal insulation cotton material uses light, soft and highly fluffy PP cotton or fiber products with a fineness of 3-18; the thickness of the thermal insulation filler is 0.3-1cm.

[0046] The present invention also provides a method for preparing a wearable thermoelectric bracelet, which comprises the following steps:

[0047] S1. Add 0.05-0.2g of N-type material, 3-10wt% of dispersant hexadecyltrimethylammonium bromide and 5-15wt% of polyurethane to 5-20ml of solvent, ultrasonicate and stir to make N-type coating. Specifically, the N-type material adopts one of nitrogen-doped multi-walled carbon nanotubes, bismuth telluride and nitrogen-doped graphene, dispersed in an aqueous solution to make a slurry, and its film-forming property is improved by adding 5-15wt% of polyurethane. Preferably, the concentration range of nitrogen-doped multi-walled carbon nanotubes in the N-type coating is 5-15mg / mL.

[0048] S2. Add 5-10V% dimethyl sulfoxide to 2-10ml of P-type material and stir to prepare P-type coating. Specifically, the P-type material is a commercial PEDOT:PSS aqueous dispersion, and its conductivity is improved by doping 5-10V% dimethyl sulfoxide.

[0049] S3, the P-type coating and the N-type coating are sequentially coated in parallel arrays in two columns on the flexible substrate, one column starts with the P-type material and the other starts with the N-type, the P and N-type materials in the two columns correspond to each other in turn, and the P and N-type materials in each column are arranged alternately, and then the P and N-type thermoelectric coatings are connected end to end with a conductive material in the following manner: the P and N-type thermoelectric coatings corresponding to the left and right are connected side by side, and the adjacent rows are sequentially connected end to end to form an electrical series path. Preferably, the substrate is made of flexible fiber paper 4 or natural fiber and its products or chemical fiber and its products.

[0050] S4, fold the substrate coated with thermoelectric material along the center line of the silver-coated area in the middle and join the edges to form a hollow strip; fill the hollow part with insulation material, then bend and join the ends into a ring to form a 3D ring structure, and obtain a total mass of 3-5g and a density of 0.053g / cm 3 Wearable thermoelectric bracelets of about 100 mm. Preferably, the material of the thermal insulation material is light, soft, and fluffy PP cotton or fiber products with a fineness of 3-18, and the thickness of the thermal insulation filler is 0.3-1 cm. The prepared P and N type thermoelectric coatings are coated in parallel and alternately in an array on the flexible substrate using a brush combined with a mask.

[0051] Example 1

[0052] 1. Add 1g CTAB (dispersant hexadecyltrimethylammonium bromide) to 19ml deionized water to prepare a 5% CTAB aqueous solution; add 2g WPU (polyurethane) to the CTAB aqueous solution, and after it is evenly dispersed, add 10wt% nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs), ultrasonicate for 1h, and then stir for 2h to prepare N-type coating.

[0053] 2. Add 0.2 ml of dimethyl sulfoxide (DMSO) to 2.8 ml of poly (3,4-ethylenedioxythiophene:polystyrene sulfonic acid) (PEDOT:PSS) and stir for 24 hours to obtain a P-type coating.

[0054] 3. Use a brush to apply P-type paint and N-type paint in an array on the substrate in turn through the pre-prepared mask, and then use silver glue to connect the P and N-type thermoelectric paints in turn to form an electrical series path.

[0055] 4. Fold the flexible fiber paper substrate coated with thermoelectric material along both sides of the center line and sew it with needle and thread to form a strip; fill it with thermal insulation material with a thickness of 1 cm, and then bend it into a ring shape to form a 3D ring structure to obtain a three-dimensional wearable thermoelectric bracelet.

[0056] 5. As Figure 5As shown, connect a multimeter to the wristband obtained in this example to test whether the wristband can generate voltage; that is, connect the positive probe of the multimeter to the P-type material at one end of the wristband, and connect the negative probe to the N-type material at the other end of the wristband to form a closed loop, and measure the stable voltage generated by this thermoelectric wristband. Figure 6 As shown, after testing, when the temperature difference between human skin and the outside world is 5.4℃, the thermoelectric bracelet can generate a voltage of 3.5mV.

[0057] Example 2

[0058] 1. Add 1g CTAB to 19ml deionized water to prepare a 5% CTAB aqueous solution; add 2g WPU to the CTAB aqueous solution, and after it is evenly dispersed, add 5wt% nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs), ultrasonicate for 1h, and then stir for 2h to prepare N-type coating.

[0059] 2. Add 0.2 ml of dimethyl sulfoxide (DMSO) to 2.8 ml of poly (3,4-ethylenedioxythiophene:polystyrene sulfonic acid) (PEDOT:PSS) and stir for 24 hours to obtain a P-type coating.

[0060] 3. Use a brush to apply P-type paint and N-type paint in an array on the substrate in turn through the pre-prepared mask, and then use silver glue to connect the P and N-type thermoelectric paints in turn to form an electrical series path.

[0061] 4. Fold the flexible fiber paper substrate coated with thermoelectric material back along both sides of the center line and sew it with needle and thread to form a strip; fill it with thermal insulation material with a thickness of 0.8 cm, and then bend it into a ring shape to form a 3D ring structure to obtain a three-dimensional wearable thermoelectric bracelet.

[0062] 5. Connect a multimeter to the wristband obtained in this example to test whether the wristband can generate voltage; that is, connect the positive probe of the multimeter to the P-type material at one end of the wristband, and the negative probe to the N-type material at the other end of the wristband to form a closed loop, and measure the stable voltage generated by the thermoelectric wristband. After testing, when the temperature difference between human skin and the outside world is 5.7℃, the thermoelectric wristband can generate a voltage of 3.1mV.

[0063] Example 3

[0064] 1. Add 1g CTAB to 19ml deionized water to prepare a 5% CTAB aqueous solution; add 2g WPU to the CTAB aqueous solution, and after it is evenly dispersed, add 15wt% nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs), ultrasonicate for 1h, and then stir for 2h to prepare N-type coating.

[0065] 2. Add 0.2 ml of dimethyl sulfoxide (DMSO) to 2.8 ml of poly (3,4-ethylenedioxythiophene:polystyrene sulfonic acid) (PEDOT:PSS) and stir for 24 hours to obtain a P-type coating.

[0066] 3. Use a brush to apply P-type paint and N-type paint in an array on the substrate in turn through the pre-prepared mask, and then use silver glue to connect the P and N-type thermoelectric paints in turn to form an electrical series path.

[0067] 4. Fold the flexible fiber paper substrate coated with thermoelectric material along both sides of the center line and sew it with needle and thread to form a strip; fill it with thermal insulation material with a thickness of 1 cm, and then bend it into a ring shape to form a 3D ring structure to obtain a three-dimensional wearable thermoelectric bracelet.

[0068] 5. Connect a multimeter to the wristband obtained in this example to test whether the wristband can generate voltage; that is, connect the positive probe of the multimeter to the P-type material at one end of the wristband, and the negative probe to the N-type material at the other end of the wristband to form a closed loop, and measure the stable voltage generated by the thermoelectric wristband. After testing, when the temperature difference between human skin and the outside world is 6.2℃, the thermoelectric wristband can generate a voltage of 3.9mV.

[0069] The background section of the present invention may contain background information about the problem or environment of the present invention, but does not necessarily describe the prior art. Therefore, the content included in the background section is not an admission by the applicant that the prior art is available.

[0070] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, it can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of the reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A method for preparing a wearable thermoelectric bracelet, characterized in that: The method comprises the following steps: S1, adding 0.05-0.2 g of N-type thermoelectric material, 3-10 wt % of dispersant hexadecyltrimethylammonium bromide and 5-15 wt % of polyurethane into 5-20 ml of solvent, ultrasonically stirring and preparing N-type coating (1); S2, adding 5-10V% dimethyl sulfoxide into 2-10ml of P-type thermoelectric material and stirring to prepare P-type coating (2); S3, coating the P-type coating (2) and the N-type coating (1) in parallel arrays on the flexible substrate in two columns, each column forming a plurality of alternating P-type coating areas (2) and N-type coating areas (1); one column starts with the P-type coating area (2), and the other column starts with the N-type coating area (1), the P-type and N-type coating areas of the two columns correspond to each other on the left and right, and the P-type and N-type coating areas of each column are arranged alternately, and then the P-type and N-type coating areas are connected end to end with a conductive material in the following manner: the P-type and N-type coating areas corresponding to each other on the left and right are connected, and the adjacent rows are connected end to end in sequence, so as to form an electrically series path; S4. Fold the substrate coated with thermoelectric material along the center line of the middle silver-coated area and join the edges to form a hollow strip; fill the hollow part with insulation material, then bend and join the ends into a ring to form a 3D ring structure to obtain a wearable thermoelectric bracelet.

2. The method for preparing a wearable thermoelectric bracelet according to claim 1, characterized in that: In step S1, the N-type coating is one of nitrogen-doped multi-walled carbon nanotubes, bismuth telluride, and nitrogen-doped graphene, which is dispersed in an aqueous solution to form a slurry, and its film-forming property is improved by adding 5-15wt% of polyurethane.

3. The method for preparing a wearable thermoelectric bracelet according to claim 1, characterized in that: In step S1, the concentration of nitrogen-doped multi-walled carbon nanotubes in the N-type coating is in the range of 5-15 mg / mL.

4. The method for preparing a wearable thermoelectric bracelet according to claim 1, characterized in that: In step S2, the P-type material used is a commercial PEDOT:PSS aqueous dispersion, and its conductivity is increased by doping 5-10V% of dimethyl sulfoxide.

5. The method for preparing a wearable thermoelectric bracelet according to claim 1, characterized in that: In step S3, the substrate used is flexible fiber paper (4) or natural fiber and its products or chemical fiber and its products.

6. The method for preparing a wearable thermoelectric bracelet according to claim 1, characterized in that: In step S4, the thermal insulation cotton is made of PP cotton or fiber products.

7. The method for preparing a wearable thermoelectric bracelet according to claim 1, characterized in that: In step S4, the thickness of the thermal insulation material is 0.3-1 cm.

8. The method for preparing a wearable thermoelectric bracelet according to claim 1, characterized in that: In step S4, a brush combined with a mask is used to apply the prepared P and N type thermoelectric coatings in a parallel and alternating array on the flexible substrate.

9. The method for preparing a wearable thermoelectric bracelet according to claim 1, characterized in that: In step S4, the total mass of the bracelet is 3-5g, and the density is 0.053g / cm 3 about.

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