Flexible temperature sensor and preparation method thereof

Abstract

The invention discloses a flexible temperature sensor and a preparation method thereof, the flexible temperature sensor comprises a thermoelectric film, a polymer material, a metal material, an electrode and a wire, the upper surface of the polymer material is provided with a wedge-shaped groove, the wedge-shaped groove is filled with the metal material, the thermoelectric film is fixed on the lower surface of the polymer material and corresponds to the position of the wedge-shaped groove, and the electrode is fixed on the polymer material. The electrode is fixed on the thermoelectric film, the wire is connected to the electrode, and the thermal conductivity of the metal material is higher than that of the polymer material. The gradient composite structure design is adopted, the low-thermal-conductivity polymer material with the wedge-shaped groove is integrated on the upper surface of the thermoelectric thin film, and the high-thermal-conductivity metal material is filled in the low-thermal-conductivity polymer material to form a heat conduction channel. An asymmetric heat conduction path is constructed through the heat conductivity difference between a polymer material and a metal material, a self-generated temperature gradient is generated when a single heat source is in contact, the thermoelectric film is induced to output a linear thermoelectric force signal, and temperature sensing without an external temperature difference device is achieved. The method can be widely applied to the technical field of sensor preparation.

Description

Technical Field

[0001] This application relates to the technical field of sensor preparation, and particularly to a flexible temperature sensor and a preparation method thereof. Background Art

[0002] The core objectives of thermoelectric material optimization and structural innovation respectively focus on performance improvement and wearable integration, but the existing technologies are still restricted by testing conditions. The traditional thermoelectric effect relies on the temperature difference at both ends of the device to drive. Whether through material modification or structural innovation, it is necessary to construct an upper-lower or left-right temperature difference field to achieve the directional transport of carriers. Therefore, the current technology still needs to further optimize the energy conversion efficiency and environmental adaptability of thermoelectric devices through material-structure co-design to meet the requirements of miniaturization, flexibility, and maintenance-free in practical applications. Summary of the Invention

[0003] To solve the above technical problems, the purpose of the present invention is to provide a flexible temperature sensor that can establish a self-sustaining temperature gradient when in contact with a single heat source and a preparation method thereof.

[0004] To achieve the above purpose, on the one hand, an embodiment of the present application proposes a flexible temperature sensor, including a thermoelectric thin film, a polymer material, a metal material, electrodes, and wires. A wedge-shaped groove is provided on the upper surface of the polymer material, and the metal material is filled in the wedge-shaped groove. The thermoelectric thin film is fixed on the lower surface of the polymer material and corresponds to the position of the wedge-shaped groove. The electrodes are fixed on the thermoelectric thin film, and the wires are connected to the electrodes. Among them, the thermal conductivity of the metal material is higher than that of the polymer material.

[0005] In some embodiments, the flexible temperature sensor further includes a packaging material, and the packaging material is packaged on the upper surface of the metal material.

[0006] In some embodiments, the thermoelectric thin film is a thermoelectric material with the Seebeck effect, and when one side of the thermoelectric thin film has a higher temperature than the other side, a potential difference is generated.

[0007] In some embodiments, the polymer material includes, but is not limited to, one of polydimethylsiloxane, polybutylene adipate-co-terephthalate, styrene-ethylene-butylene-styrene copolymer, or thermoplastic polyurethane.

[0008] In some embodiments, the metal material includes, but is not limited to, one of gallium-indium alloy, indium-tin alloy, gallium-indium-tin alloy, bismuth-based alloy, gallium, or indium.

[0009] To achieve the above purpose, on the other hand, an embodiment of the present application proposes a preparation method of a flexible temperature sensor, including the following steps:

[0010] Print a soft silicone mold with a wedge structure;

[0011] Pour the pre-treated polymer material into the soft silicone mold, and cure it to obtain a polymer material layer with a flat lower surface and an array of wedge-shaped grooves on the upper surface;

[0012] Print a thermoelectric thin film on the lower surface of the polymer material layer corresponding to the array of wedge-shaped grooves to obtain a thermoelectric thin film layer;

[0013] Print electrodes on the thermoelectric thin film layer, connect wires to the electrodes, and then cut the array of wedge-shaped grooves into individual wedge-shaped grooves;

[0014] Fill the individual wedge-shaped grooves with a metal material until the wedge-shaped grooves are filled to obtain the flexible temperature sensor;

[0015] Wherein, the thermal conductivity of the metal material is higher than that of the polymer material.

[0016] In some embodiments, before injecting the metal material into the wedge-shaped groove, it further includes:

[0017] Encapsulate the upper surface of the metal material with a packaging material.

[0018] The beneficial effects of the present invention are as follows: The flexible temperature sensor and its preparation method of the present invention. The flexible temperature sensor includes a thermoelectric thin film, a polymer material, a metal material, electrodes, and wires. By designing a polymer material with wedge-shaped grooves and poor thermal conductivity above the thermoelectric thin film and filling the wedge-shaped grooves with a metal material with good thermal conductivity, an asymmetric heat conduction path is formed, thereby forming a temperature gradient. This structure can establish a self-sustaining temperature gradient when in contact with a single heat source through the gradient distribution of the thermal conductivity of the materials, realizing temperature sensing. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following introduces the drawings required to be used in the embodiments of the present invention. It should be understood that the drawings introduced below are only for conveniently and clearly expressing some embodiments of the technical solutions in the present invention. For those skilled in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a three-dimensional structure schematic diagram of a flexible temperature sensor provided by an embodiment of the present invention;

[0021] Figure 2 It is a schematic diagram of wedge-shaped grooves with different heights provided by an embodiment of the present invention;

[0022] Figure 3 Device performance comparison chart of wedge-shaped grooves with different heights provided by the embodiments of the present invention;

[0023] Figure 4 Flowchart of the steps of a preparation method of a flexible temperature sensor provided by the embodiments of the present invention;

[0024] Figure 5 Schematic diagram of the preparation process of the flexible temperature sensor provided by the embodiments of the present invention;

[0025] Figure 6 Structure comparison chart of the flexible temperature sensor with a wedge-shaped structure and left and right heat conduction structures provided by the embodiments of the present invention;

[0026] Figure 7 Performance comparison chart of the flexible temperature sensor with a wedge-shaped structure and left and right heat conduction structures provided by the embodiments of the present invention. Detailed implementation manners

[0027] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. When the following description relates to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all the implementation manners consistent with the embodiments of the present application. They are only examples of devices and methods consistent with some aspects of the embodiments of the present application detailed in the appended claims.

[0028] It can be understood that the terms "first", "second", etc. used in the present application may be used in this document to describe various concepts, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if", "when" as used herein may be interpreted as "when...", "while...", or "in response to determining".

[0029] The terms "at least one", "a plurality of", "each", "any one", etc. used in the present application, at least one includes one, two or more, a plurality of includes two or more, each refers to each of the corresponding plurality, and any one refers to any one of the plurality.

[0030] The Seebeck effect refers to the phenomenon that in a closed loop composed of two different conductors, when the two contact points are at different temperatures, an electromotive force will be generated in the loop. Taking a p-type semiconductor thin film as an example, the hole concentration at the hot end is high and will diffuse towards the cold end. In the open-circuit state, space charges are formed at both ends of the p-type semiconductor, with the hot end being negatively charged and the cold end being positively charged, and an internal electric field is generated. When the diffusion and the drift effect of the electric field reach equilibrium, a stable state is achieved, and an electromotive force caused by the temperature gradient, i.e., the thermoelectric electromotive force, appears at both ends. For an n-type semiconductor, the situation is opposite, and the thermoelectric electromotive force points from the low-temperature end to the high-temperature end.

[0031] Based on the Seebeck effect, thermoelectric thin films can directly convert temperature gradients into electrical energy and show great application potential in the fields of energy, sensing, and healthcare. This technology can utilize industrial waste heat, automobile exhaust, or environmental temperature differences to achieve distributed power generation, significantly improving energy utilization efficiency; in the fields of wearable devices and the Internet of Things, self-powered systems can be constructed to get rid of the dependence on traditional batteries; its miniaturization and flexibility are suitable for scenarios such as medical monitoring patches and electronic skin, enabling real-time body temperature monitoring and non-contact sensing.

[0032] The core objectives of optimizing thermoelectric materials and innovating structures are focused on performance improvement and wearable integration respectively, but the existing technologies are still restricted by testing conditions. Traditional thermoelectric effects rely on the temperature difference at both ends of the device to drive. Whether through material modification or structural innovation, a temperature difference field in the up-down or left-right direction needs to be constructed to achieve the directional transport of carriers. Therefore, the current technology still needs to further optimize the energy conversion efficiency and environmental adaptability of thermoelectric devices through the collaborative design of materials and structures to meet the requirements of miniaturization, flexibility, and maintenance-free in practical applications.

[0033] For this reason, the embodiment of the present invention proposes a flexible temperature sensor. The flexible temperature sensor includes a thermoelectric thin film, a polymer material with low thermal conductivity, a metal material with high thermal conductivity, electrodes, and wires. By designing a polymer material with a wedge-shaped groove and poor thermal conductivity above the thermoelectric thin film and filling the wedge-shaped groove with a metal material with good thermal conductivity, an asymmetric heat conduction path is formed, thereby forming a temperature gradient. This structure can establish a self-sustaining temperature gradient when in contact with a single heat source through the gradient distribution of the thermal conductivity of the materials, thus realizing temperature sensing. This flexible temperature sensor is suitable for the mass production of flexible electronic devices and has significant technical advantages especially in the integrated application fields of minimally invasive medical temperature measurement patches, new energy battery thermal management modules, and spacecraft surface temperature monitoring systems.

[0034] Refer to Figure 1 , Figure 1A three-dimensional structural schematic diagram of a flexible temperature sensor provided by an embodiment of the present invention. An embodiment of the present invention proposes a flexible temperature sensor, which includes a thermoelectric thin film, a polymer material, a metal material, electrodes, and wires. A plurality of wedge-shaped grooves are provided on the upper surface of the polymer material, and the metal material is filled in the wedge-shaped grooves. The thermoelectric thin film is fixed on the lower surface of the polymer material and corresponds to the position of the wedge-shaped grooves. The electrodes are fixed on the thermoelectric thin film, and the wires are connected to the electrodes. Among them, the thermal conductivity of the metal material is higher than that of the polymer material.

[0035] Specifically, in the embodiment of the present invention, two materials with different thermal conductivities are added above the thermoelectric thin film ( Figure 1 the green part in it). Figure 1 The purple one is a polymer material with poor thermal conductivity, and the red one is a metal material with good thermal conductivity. Under the action of a heat source, the volume ratio of the polymer and the metal in the three-dimensional space shows a continuous gradient change along the axial direction - specifically, the polymer volume fraction decreases from left to right, while the metal volume fraction increases, forming an asymmetric conduction path, thereby forming a temperature gradient. This structure breaks through the dependence of traditional thermoelectric sensors on the temperature difference between two heat sources. The difference in thermal conductivity of heterogeneous materials leads to the redistribution of heat flux density in the transverse direction. Specifically, a fast heat dissipation channel is formed in the metal region due to high thermal conductivity, while local heat accumulation is generated due to the thermal resistance effect in the polymer region. The synergistic effect of the two enables a stable Seebeck potential to be spontaneously formed on the surface of the thermoelectric thin film, so that a self-sustaining temperature gradient can be established when in contact with a single heat source, realizing temperature sensing.

[0036] It should be noted that the material of the electrodes can be selected according to actual needs, such as silver electrodes, copper electrodes, aluminum electrodes, etc., and no limitation is made here.

[0037] Further as an optional implementation manner, the flexible temperature sensor further includes a packaging material, and the packaging material is packaged on the upper surface of the metal material.

[0038] In some optional embodiments, the packaging material can be a copper tape. The upper surface of the polymer material provided with wedge-shaped grooves is packaged with the copper tape, and the bottom of the flexible temperature sensor (i.e., the side of the thermoelectric thin film and the electrodes, in direct contact with the electrodes) can be packaged with a polyimide tape to improve the stability and service life of the device.

[0039] Further as an optional implementation manner, the thermoelectric thin film is a thermoelectric material with the Seebeck effect, and when one side of the thermoelectric thin film is at a higher temperature than the other side, a potential difference is generated.

[0040] It should be noted that the material of the thermoelectric thin film is selected from thermoelectric materials with the Seebeck effect, which can be thermoelectric materials such as poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS), Bi2Te3, PbTe, Sb2Te3, etc., or can be selected according to actual needs, and are not limited herein.

[0041] Exemplarily, in the embodiment of the present invention, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) is used as the thermoelectric thin film. Poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) is a temperature-sensitive material and can generate a thermoelectric potential at different temperatures.

[0042] Further as an optional implementation manner, the polymer material includes but is not limited to one of polydimethylsiloxane, polybutylene adipate-co-terephthalate, styrene-ethylene-butylene-styrene copolymer, or thermoplastic polyurethane.

[0043] It should be noted that other materials with poor thermal conductivity can also be selected for the polymer material according to actual needs, and are not limited herein.

[0044] Exemplarily, in the embodiment of the present invention, polydimethylsiloxane (PDMS) is used as the polymer material to form a temperature gradient with the metal material. Polydimethylsiloxane (PDMS) is an organosilicon polymer, whose main chain is composed of silicon-oxygen bonds (Si—O—Si), and the side chains are methyl groups (CH3). This structure results in weak intermolecular forces, and heat conduction mainly occurs through phonon transfer, so its intrinsic thermal conductivity is relatively low (about 0.15 W / m·K).

[0045] Further as an optional implementation manner, the metal material includes but is not limited to one of gallium-indium alloy, indium-tin alloy, gallium-indium-tin alloy, bismuth-based alloy, gallium, or indium.

[0046] It should be noted that other materials with good thermal conductivity and temperature can also be selected for the metal material according to actual needs, and are not limited herein.

[0047] Exemplarily, in the embodiment of the present invention, a liquid metal (LM) with strong thermal conductivity is used as the metal material, whose main component is gallium-indium alloy, and its specific parameters are a melting point of 16 °C, a boiling point of 2000 °C, and a thermal conductivity of about 26.6 W / m / K.

[0048] In summary, the flexible temperature sensor proposed in the embodiments of the present invention is composed of copper tape, polydimethylsiloxane (PDMS), gallium-indium alloy, thermoelectric thin film (PEDOT:PSS), electrodes, and wires (silver-plated copper wires are used in the embodiments of the present invention). Among them, the thermoelectric thin film (PEDOT:PSS) is a temperature-sensitive material that can generate thermoelectric potential at different temperatures; polydimethylsiloxane (PDMS) is a material with poor thermal conductivity; liquid metal is a material with good thermal conductivity, and the two form a temperature gradient under the design of the wedge structure; the copper tape is used to introduce heat sources and encapsulate the wedge-shaped grooves; the electrodes and silver-plated copper wires are used to output signals to realize the reading of the potential.

[0049] The structure of the flexible temperature sensor proposed in the embodiments of the present invention is described above. Next, its working principle will be described: When the heat source contacts the copper tape, the heat rapidly diffuses through the high-thermal-conductivity base layer. Since the thermal conductivity coefficients of the gallium-indium alloy and polydimethylsiloxane (PDMS) differ by two orders of magnitude (0.15 W / m / K vs 26.6 W / m / K), it causes spatiotemporal separation of the heat flow during longitudinal transfer: the heat in the gallium-indium alloy region penetrates rapidly, while the polydimethylsiloxane (PDMS) region forms a heat lag zone. This heterogeneous heat transfer behavior generates a stable axial temperature gradient ΔT at the interface of the thermoelectric thin film. Based on the Seebeck effect, the temperature gradient ΔT drives the carriers to migrate directionally within the thermoelectric thin film (PEDOT:PSS), generating an output voltage V = αΔT (α is the Seebeck coefficient) that is proportional to ΔT.

[0050] It should be noted that as Figure 2 shown is a schematic diagram of wedge-shaped grooves with different heights (1 mm, 2 mm, 3 mm), and as Figure 3 shown is a comparison diagram of the device performance of wedge-shaped grooves with different heights (1 mm, 2 mm, 3 mm). Keeping the temperature at the lower end of the device at room temperature and gradually heating the temperature at the upper end from 25°C to 50°C, the flexible temperature sensor generates a voltage, that is, thermoelectric potential, at different temperatures. When the temperature gradually increases, the thermoelectric potential of the device becomes larger. Figure 3The three curves in [Figure 0] respectively represent the influence of wedge-shaped grooves with different heights on the performance of the flexible temperature sensor. It can be seen that when the height of the wedge-shaped groove is smaller, the sensitivity S and linearity R of the flexible temperature sensor are higher, that is, the performance of the flexible temperature sensor is better. Therefore, in the embodiment of the present invention, the size of the wedge-shaped groove is set to 5 mm in length * 5 mm in width * 1 mm in height, and the size of the thermoelectric thin film (PEDOT:PSS) corresponding to the lower end of the wedge-shaped groove is also set to 5 mm in length * 5 mm in width to enhance the performance of the flexible temperature sensor. It should be noted that the size of the wedge-shaped groove can also be set according to actual needs. For example, the size of the wedge-shaped groove can be set to 7 mm in length * 7 mm in width * 1 mm in height, 5 mm in length * 5 mm in width * 0.5 mm in height, 4 mm in length * 4 mm in width * 0.8 mm in height, etc., which is not limited herein.

[0051] The structure and working principle of the flexible temperature sensor in the embodiment of the present invention are described above. It can be recognized that compared with the existing thermoelectric devices, the embodiment of the present invention has the following advantages:

[0052] (1) By designing a polymer substrate with triangular wedge-shaped grooves on the surface of the thermoelectric thin film and filling the grooves with a highly thermally conductive metal, an asymmetric temperature gradient can be spontaneously formed under a single heat source contact, so as to generate a thermoelectric potential through the Seebeck effect and complete the temperature sensing function. This design combines the microstructural topology optimization with the difference in thermal conductivity of heterogeneous materials, breaking through the limitation that traditional thermoelectric sensors require a temperature difference at both ends and significantly improving the integration of the device.

[0053] (2) When the wedge height is too large, heat needs to be transferred to the sensing element through a longer path, resulting in a thermal response delay. This may lead to a decrease in the sensor sensitivity, especially in the dynamic temperature monitoring scenario. On the contrary, if the height is too small, the thickness of the thermal boundary layer is insufficient, and heat is easily dissipated to the surrounding environment quickly, making it difficult to form a stable temperature gradient. Therefore, in the embodiment of the present invention, through experimental comparison, the height of the wedge-shaped groove is set to 1 mm, which can significantly improve the performance of the flexible temperature sensor.

[0054] Refer to Figure 4 , Figure 4 [Figure 16] is a flowchart of the steps of a preparation method of a flexible temperature sensor provided by an embodiment of the present invention. The embodiment of the present invention also provides a preparation method of a flexible temperature sensor, including the following steps S101 to S105:

[0055] S101. Print a soft silicone mold with a wedge-shaped structure;

[0056] S102. Pour the pre-treated polymer material into the soft silicone mold and cure it to obtain a polymer material layer with a flat lower surface and a wedge-shaped groove array on the upper surface;

[0057] S103. Print a thermoelectric thin film at the lower surface of the polymer material layer and corresponding to the wedge-shaped groove array to obtain a thermoelectric thin film layer;

[0058] S104. Print electrodes on the thermoelectric thin film layer, connect wires to the electrodes, and then cut the wedge-shaped groove array into individual wedge-shaped grooves;

[0059] S105. Fill the individual wedge-shaped grooves with a metal material until the wedge-shaped grooves are filled to obtain a flexible temperature sensor;

[0060] Wherein, the thermal conductivity of the metal material is higher than that of the polymer material.

[0061] Further as an optional implementation manner, before injecting the metal material into the wedge-shaped groove, the following steps are further included:

[0062] S113. Encapsulate the upper surface of the metal material with a packaging material.

[0063] Specifically, as Figure 5 shown is a schematic diagram of the preparation process of the flexible temperature sensor. First, use 3D printing to print the required soft silicone mold. The overall size of the illustrated soft silicone mold is 38mm * 38mm, and the length, width, and height of a single wedge are 5mm * 5mm * hmm (the height h can be customized to any height, and h in the embodiments of the present invention is 1mm, 2mm, or 3mm), the distance between individual wedges is 7mm, the distance from a single wedge to the wall is 3.5mm, and the wall thickness on one side is 1mm. Then pour the stirred polydimethylsiloxane (m 聚二甲基硅氧烷 : m 固化剂 = 10:1) into the printed soft silicone mold and dry it. After curing, a polymer material layer with a flat lower surface and a wedge-shaped groove array on the upper surface can be obtained. Then use copper tape to encapsulate the upper surface with the wedge-shaped groove array. Furthermore, print a thermoelectric thin film (PEDOT:PSS) on the lower surface of the polymer material layer. The dispensing method in a flexible electronic printer is used for printing. The size of the thermoelectric thin film (PEDOT:PSS) is 5mm * 5mm, and the specific parameters are a needle size of 160μm, a dispensing speed of 1mm / s, and a pressure of 160kPa. Then print the electrodes. The size of the electrodes is 2mm * 7mm, and the dispensing method in the flexible electronic printer is also used. Set the needle size to 210μm, the dispensing speed to 1mm / s, and the pressure to 200kPa. Subsequently, cut it into individual wedge-shaped grooves, and then use copper tape to encapsulate the upper surface with the wedge-shaped grooves. Then use silver-plated copper wire for wiring and use medical tape for encapsulation, and then use polyimide tape to encapsulate the bottom of the device. Finally, inject gallium indium alloy into the upper surface of the wedge-shaped groove encapsulated with copper tape after step S113 until the wedge-shaped groove is filled. Thus, a flexible temperature sensor based on the temperature gradient generated by the wedge-shaped structure is made.

[0064] The content in the above embodiments of the flexible temperature sensor is applicable to the embodiments of the preparation method of the present flexible temperature sensor. The functions specifically achieved by the embodiments of the preparation method of the present flexible temperature sensor are the same as those of the above embodiments of the flexible temperature sensor, and the beneficial effects achieved are also the same as those of the above embodiments of the flexible temperature sensor.

[0065] The performance of the flexible temperature sensor according to the embodiments of the present invention will be described below in combination with different device structure designs and material designs.

[0066] As Figure 6 shown is a structural comparison diagram of a flexible temperature sensor with a wedge structure and left and right heat conduction structures (equal division design of polymer material and metal material on the left and right). As Figure 7 shown is a performance comparison diagram of a flexible temperature sensor with a wedge structure and left and right heat conduction structures. As can be seen from Figure 7 it, under the same design dimensions (length 5mm * width 5mm * height 1mm) and applied temperature (25°C - 50°C), the thermoelectric potential generated by the flexible temperature sensor with left and right heat conduction structures is 22.9 μV, and the thermoelectric potential generated by the flexible temperature sensor with a wedge structure is 94.6 μV. It can be seen that the flexible temperature sensor with a wedge structure has a more significant temperature gradient and can generate a larger thermoelectric potential under a single heat source contact.

[0067] In the above description of this specification, the description with reference to terms such as "one embodiment / embodiment", "another embodiment / embodiment" or "certain embodiments / embodiments" means that the specific features, structures, materials or characteristics described in connection 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 refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0068] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and purposes of the present invention. The scope of the present invention is defined by the claims and their equivalents.

[0069] The above has specifically described the preferred embodiments of the present invention, but the present invention is not limited to the embodiments. Those skilled in the art can also make various equivalent deformations or substitutions without departing from the spirit of the present invention, and these equivalent deformations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A flexible temperature sensor, characterized in that, It includes a thermoelectric thin film, a polymer material, a metal material, electrodes, and wires. A wedge-shaped groove is provided on the upper surface of the polymer material, and the metal material is filled in the wedge-shaped groove. The thermoelectric thin film is fixed on the lower surface of the polymer material and corresponds to the position of the wedge-shaped groove. The electrodes are fixed on the thermoelectric thin film, and the wires are connected to the electrodes. Among them, the thermal conductivity of the metal material is higher than that of the polymer material.

2. The flexible temperature sensor according to claim 1, characterized in that, The flexible temperature sensor further includes a packaging material, and the packaging material is packaged on the upper surface of the metal material.

3. The flexible temperature sensor according to claim 1, wherein The thermoelectric thin film is a thermoelectric material with the Seebeck effect, and when the temperature on one side of the thermoelectric thin film is higher than that on the other side, a potential difference is generated.

4. The flexible temperature sensor according to claim 1, characterized in that, The polymer material includes but is not limited to one of polydimethylsiloxane, poly(butylene adipate-co-terephthalate), styrene-ethylene-butylene-styrene copolymer, or thermoplastic polyurethane.

5. The flexible temperature sensor according to claim 1, characterized in that, The metal material includes but is not limited to one of gallium-indium alloy, indium-tin alloy, gallium-indium-tin alloy, bismuth-based alloy, gallium, or indium.

6. A preparation method of a flexible temperature sensor for preparing the flexible temperature sensor according to any one of claims 1 to 5, characterized in that, It includes the following steps: Print a soft silicone mold with a wedge-shaped structure. Pour the pre-treated polymer material into the soft silicone mold and cure it to obtain a polymer material layer with a flat lower surface and an array of wedge-shaped grooves on the upper surface. Print a thermoelectric thin film at the position on the lower surface of the polymer material layer corresponding to the array of wedge-shaped grooves to obtain a thermoelectric thin film layer. Print electrodes on the thermoelectric thin film layer, connect wires to the electrodes, and then cut the array of wedge-shaped grooves into individual wedge-shaped grooves. Fill the individual wedge-shaped grooves with a metal material until the wedge-shaped grooves are filled to obtain the flexible temperature sensor. Among them, the thermal conductivity of the metal material is higher than that of the polymer material.

7. The preparation method according to claim 6, characterized in that, The preparation method further includes: Package the upper surface of the metal material with a packaging material.

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