A conformal heating film and its preparation method and application

Abstract

The embodiments of the present invention propose a conformal heating film and a preparation method and application thereof, which relate to the field of thermal research. The conformal heating film includes a stretchable flexible shell, in which a stretchable thermal sensing module array layer, a heating circuit packaging layer and a stretchable heating circuit are sequentially arranged, and the stretchable thermal sensing module array layer and the stretchable heating circuit are respectively fixedly installed on both sides of the heating circuit packaging layer, and the positive and negative electrodes of the stretchable heating circuit respectively penetrate the stretchable flexible shell. By arranging a stretchable thermal sensing module array layer inside the conformal heating film, it can be ensured that during the conformal deformation process of the conformal heating film, the stretchable thermal sensing module array layer can stably measure the temperature of the fixed position of the conformal heating film. The conformal heating film with integrated temperature monitoring function can be applied to various complex curved surfaces, such as human body, pipelines, aircraft wings and clothing, to play the function of heating and monitoring temperature.

Description

Technical Field

[0001] The present invention relates to the field of thermal research, and in particular to a conformal heating film and a preparation method and application thereof. Background Art

[0002] If the surface temperature of aircraft, wind turbine blades, radar antenna covers and heating clothing is too low, it will seriously affect the normal use of the equipment. Therefore, raising the temperature of the equipment surface has become a problem that must be solved.

[0003] There are two main methods for increasing temperature: one is to set a heating circuit on the surface, that is, heating through metal elements; the other is to use a flexible heating film. A flexible heating film can be formed by sequentially depositing a dielectric layer, a metal layer, and a dielectric layer on a flexible substrate. The flexible heating film can reduce the complexity of the structure and process, while reducing the amount and type of materials used, and is suitable for complex curved surfaces.

[0004] Although flexible heating films are better suited for complex curved surfaces than metal heating elements, as the heating films deform, it is difficult to stably measure the temperature at a specific location on the heating films using external temperature monitoring devices. Summary of the invention

[0005] According to an embodiment of the present invention, a conformal heating film and a preparation method and application thereof are provided, which can solve the problem that the existing flexible heating film has poor temperature measurement stability after deformation.

[0006] In a first aspect of the present invention, a conformal heating film is provided. The conformal heating film comprises: a stretchable flexible shell, in which a stretchable thermal sensing module array layer, a heating circuit packaging layer and a stretchable heating circuit are sequentially arranged, the stretchable thermal sensing module array layer and the stretchable heating circuit are respectively fixedly mounted on both sides of the heating circuit packaging layer, and the positive electrode and the negative electrode of the stretchable heating circuit respectively penetrate the stretchable flexible shell.

[0007] Furthermore, the stretchable flexible shell includes a flexible substrate and an upper packaging layer, and the flexible substrate and the upper packaging layer are sealed and connected.

[0008] Furthermore, the stretchable heating circuit is a metal film with a plurality of hollow holes, the hollow holes are arranged in an array, and the edge lines of the hollow holes are curves.

[0009] Furthermore, the stretchable thermal sensing module array layer includes a plurality of thermal sensing modules arranged in an array, two adjacent thermal sensing modules are connected by a curved wire, and the thermal sensing module is located at the center of the hollow hole.

[0010] Preferably, the lengths of the edge lines of the hollow holes are the same, and the lengths of the curved wires are the same.

[0011] Furthermore, the stretchable flexible shell and the heating circuit packaging layer are both made of aliphatic aromatic random copolyester.

[0012] In the second aspect of the present invention, a method for preparing a conformal heating film is provided. The method comprises: pouring a flexible insulating material into a mold and curing it, then pasting a stretchable heating circuit, pouring a flexible insulating material again and curing it to form a heating circuit packaging layer; pasting a stretchable thermal sensing module array layer on top of the cured heating circuit packaging layer; finally pouring a flexible insulating material and curing it, completing the production of a stretchable flexible shell, and demolding to obtain a conformal heating film.

[0013] Preferably, the flexible insulating material is aliphatic aromatic random copolyester, which is prepared according to components A and B, wherein A:B=1:1-3 (either mass ratio or volume ratio), stirred evenly and degassed; the curing time of each layer of aliphatic aromatic random copolyester is 5-6 hours. The mass ratio or volume ratio of components A and B is preferably 1:1.

[0014] Preferably, the thickness of the heating circuit packaging layer is 0.5-0.7 mm.

[0015] In a third aspect of the present invention, there is provided an application of a conformal heating film in aerospace, transportation, transmission lines or heating clothing (such as a smart wearable heater).

[0016] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0017] 1. A conformal heating film provided by the present invention can ensure that during the conformal deformation process of the conformal heating film, the stretchable thermal sensing module array layer can stably measure the temperature of a fixed position of the conformal heating film by arranging a stretchable thermal sensing module array layer inside the conformal heating film.

[0018] 2. The heating circuit packaging layer can effectively isolate the stretchable heating circuit and the stretchable thermal sensing module array layer, preventing the stretchable heating circuit from directly contacting the stretchable thermal sensing module array layer and affecting temperature monitoring.

[0019] 3. The conformal heating film provided by the present invention can withstand unidirectional strains exceeding 60% or multidirectional strains exceeding 10% without causing significant loss in conductivity and heating performance. Thousands of stretching and relaxing cycles also prove the good durability of the heating film. The force / electrical stability under dynamic bending / stretching is good.

[0020] It should be understood that the contents described in the summary of the invention are not intended to limit the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other features, advantages and aspects of the embodiments of the present invention will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements, wherein:

[0022] Figure 1 A schematic diagram showing the internal structure of a conformal heating film according to an embodiment of the present invention is shown;

[0023] Figure 2 A schematic structural diagram of a stretchable thermal sensing module array layer according to an embodiment of the present invention is shown;

[0024] Figure 3 A schematic structural diagram of a stretchable heating circuit according to an embodiment of the present invention is shown;

[0025] Figure 4 A schematic diagram showing a structure in which a stretchable thermal sensing module array layer and a stretchable heating circuit are installed on a heating circuit packaging layer according to an embodiment of the present invention;

[0026] Figure 5 A schematic diagram showing a structure in which a thermal sensing module is located at the center of a hollow hole according to an embodiment of the present invention;

[0027] Figure 6 A schematic diagram of the structure of a curved conductor according to an embodiment of the present invention is shown;

[0028] Figure 7 A schematic structural diagram of a curved conductor according to another embodiment of the present invention is shown;

[0029] Figure 8 A schematic structural diagram of a hollow hole edge line according to another embodiment of the present invention is shown.

[0030] Among them, 100 is a stretchable flexible shell; 101 is a flexible substrate; 103 is an upper packaging layer; 110 is a stretchable thermal sensor module array layer; 111 is a thermal sensor module; 113 is a curved wire; 130 is a heating circuit packaging layer; 150 is a stretchable heating circuit; 153 is a hollow hole. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In addition, the term "and / or" in this article is only a description of the association relationship between the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0033] like Figure 1 As shown, the conformal heating film includes a stretchable flexible shell 100, in which a stretchable thermal sensing module array layer 110, a heating circuit packaging layer 130 and a stretchable heating circuit 150 are sequentially arranged. The stretchable thermal sensing module array layer 110 and the stretchable heating circuit 150 are fixedly mounted on both sides of the heating circuit packaging layer 130, respectively. The positive electrode and the negative electrode of the stretchable heating circuit 150 respectively penetrate the stretchable flexible shell 100. The stretchable flexible shell 100 can be attached to a complex curved surface and can be stretched, and the stretchable thermal sensing module array layer 110 inside can be stretched synchronously with the stretching of the stretchable flexible shell 100, so as to ensure that the stretchable thermal sensing module array layer 110 can stably measure the temperature of a fixed position of the conformal heating film during the conformal deformation process.

[0034] When installing the conformal heating film, the staff needs to clean the surface of the device connected to the conformal heating film, apply adhesive on the surface of the device, and then stretch the conformal heating film and paste it along the surface of the device to make the conformal heating film fit the surface of the device completely. Then, the positive and negative electrodes of the stretchable heating circuit 150 are connected to the external circuit through wires, and the stretchable thermal sensing module array layer 110 is connected to the external monitoring device. At this point, the installation of the conformal heating film is completed.

[0035] Specifically, the stretchable flexible housing 100 includes a flexible substrate 101 and an upper packaging layer 103 , and the flexible substrate 101 and the upper packaging layer 103 are sealed and connected.

[0036] In this embodiment, the stretchable flexible shell 100 is made of aliphatic aromatic random copolyester material, specifically Ecoflex00-30 from SMOOTH-ON, which is very soft and very strong after curing. It can be stretched to many times its original size without tearing, and will rebound to its original shape without deformation. Ecoflex series silicone rubber is an ultra-soft platinum silicone rubber that can be naturally cured at room temperature. It has the advantages of small shrinkage, low viscosity, good fluidity, and excellent high temperature resistance. Its temperature can reach 300℃~500℃. Most importantly, the cured silicone rubber is very soft, very strong, and very "elastic". It can be stretched to several times its original size without tearing, and will rebound to its original shape without deformation. It has significant advantages in high tensile strength, tear resistance, and a large number of re-molding times.

[0037] In this embodiment, Ecoflex00-30 is only a preferred material for the stretchable flexible shell 100. In other embodiments, the stretchable flexible shell 100 may also be made of other materials with softness and excellent stretchability. For example, it may be Ecoflex00-10, Ecoflex00-20, Ecoflex00-35, Ecoflex00-50 and other series. The material may also be purchased from Shenzhen Hongyejie Technology Co., Ltd.

[0038] Specifically, the heating circuit packaging layer 130 is located between the stretchable thermal sensing module array layer 110 and the stretchable heating circuit 150 . The heating circuit packaging layer 130 is also made by curing aliphatic aromatic random copolyester material, and has a thickness of 0.5 mm.

[0039] In this embodiment, the heating circuit packaging layer 130 can not only support the overall tensile deformation of the conformal heating film, effectively isolating the heating circuit and the sensor array, but also prevent the stretchable heating circuit 150 from directly contacting the stretchable thermal sensor module array layer 110 and affecting temperature monitoring. At the same time, it has a uniforming effect on the heat diffused from the curved wire 113 and the stretchable heating circuit 150.

[0040] like Figure 1 , Figure 2 and Figure 3 As shown, the stretchable heating circuit 150 is pasted on one side of the heating circuit packaging layer 130. The stretchable heating circuit 150 is made by laser cutting process. A plurality of hollow holes 153 of the same size and shape are cut on the metal film by laser. Each hollow hole 153 is a closed hollow area composed of a plurality of curves connected end to end in sequence. The curve is the edge line of the hollow hole. The edge lines of the plurality of hollow holes 153 are connected to each other to form a heating circuit.

[0041] In this embodiment, the metal film is a Cu film. In addition, the hollow holes 153 are arranged in an array, so as to ensure that when the stretchable heating circuit 150 is stretched, the maximum stretchable length and the maximum stretchable width of the stretchable heating circuit 150 are consistent.

[0042] In this embodiment, two wires are provided, the two wires are located on both sides of the stretchable heating circuit 150, and both are welded to the stretchable heating circuit 150. The stretchable heating circuit 150 is connected to the external circuit through the two wires. The stretchable heating circuit 150 can generate heat after being powered on, and the staff can control the level of heat generated by the stretchable heating circuit 150 by controlling the output voltage.

[0043] Preferably, the edge lines of the hollow holes 153 are of the same length, and the edge lines of the hollow holes 153 adopt an antisymmetric arc structure with a semi-arc angle of 90°. The circuit structure designed based on the antisymmetric arc curve with a semi-arc angle of 90° forms a quadrilateral grid, so that when the stretchable heating circuit 150 is subjected to biaxial stretching, the hollow holes 153 can undergo nearly uniform deformation, thereby ensuring uniform heating.

[0044] like Figure 1 and Figure 4 As shown, the stretchable thermal sensing module array layer 110 is attached to the side of the heating circuit packaging layer 130 away from the stretchable heating circuit 150. The stretchable thermal sensing module array layer 110 includes a plurality of thermal sensing modules 111 arranged in an array, and two adjacent thermal sensing modules 111 are connected by a curved wire 113, which gives the stretchable thermal sensing module array layer 110 a stretchable characteristic, thereby having a conformal application advantage on a complex non-developable curved surface.

[0045] In this embodiment, the thermal sensing module 111 is an existing thermocouple temperature sensor or a thermistor temperature sensor. By setting a battery at the edge of the stretchable thermal sensing module array layer 110 and connecting the battery to the circuit for power supply, this power supply method can better ensure the sealing of the conformal heating film.

[0046] In other embodiments, the stretchable thermal sensing module array layer 110 may also be powered by an external power supply, and the external power supply connection method may be connected to the stretchable thermal sensing module array layer 110 by an extended wire, that is, during preparation, the extended wire is connected to the stretchable thermal sensing module array layer 110, and a part of the extended wire is located outside the heating circuit packaging layer 130, and when the upper packaging layer 103 and the heating circuit packaging layer 130 are sealed, the extended wire is located between the upper packaging layer 103 and the heating circuit packaging layer 130, so that the extended wire is sealed together.

[0047] like Figure 4 , Figure 5 and Figure 6As shown, when the stretchable thermal sensing module array layer 110 and the stretchable heating circuit 150 are both mounted on the heating circuit packaging layer 130, the thermal sensing module 111 is located at the center of the hollow hole 153. The thermal sensing module 111 is at the same distance from the edge line of the hollow hole 153 where it is located, and the thermal sensing module 111 always monitors the temperature in the center of the hollow hole 153, so that the measured temperature value is more accurate and balanced.

[0048] Preferably, the lengths of the curved conductors 113 are the same, and the curved conductors 113 also adopt an antisymmetric arc structure with a semi-arc angle of 90°. The circuit structure designed based on the antisymmetric arc curve with a semi-arc angle of 90° forms a quasi-quasi-grid, so that when the stretchable thermal sensing module array layer 110 is biaxially stretched, the quasi-quasi-grid composed of the curved conductors 113 and the thermal sensing modules 111 can undergo nearly uniform deformation, so that the thermal sensing module 111 is always in the center of the hollow hole 153.

[0049] Seen from a top-down perspective, the stretchable thermal sensing module array layer is connected using a curved wire 113, and each thermal sensing module is pasted at the center of the hollow hole, thereby ensuring that during the conformal deformation of the conformal heating film, the thermal sensing module is stretched together with the stretchable heating circuit and the relative position remains unchanged, and the thermal sensing module always monitors the temperature in the center of the hollow hole.

[0050] It should be noted that the arc angle of the antisymmetric arc curve is set to 90° only as a preferred option. In other embodiments, the arc angle of the edge line of the hollow hole 153 (i.e., the antisymmetric arc curve) can also be adjusted to 45°, 60°, etc., and accordingly, the angle of the curved wire 113 also needs to be adjusted. Figure 7 and Figure 8 In the figure, the arc angle of the edge line of the hollow hole 153 is 60°, the angle of the curved wire 113 is also 60°, and the thermal sensor module 111 is located at the center of the hollow hole 153.

[0051] In the above embodiment, the circuit structure designed based on an antisymmetric arc curve with a semi-arc angle of 90° forms a quadrilateral-like grid, so that under biaxial stretching, the hollow holes in the stretchable heating circuit can undergo nearly uniform deformation, thereby ensuring uniform heating.

[0052] In addition, in another embodiment of the present invention, a method for preparing a conformal heating film is provided, comprising:

[0053] S100, preparation of stretchable heating circuit:

[0054] S101, drawing the shape of the hollow hole on the surface of the metal film, the arc angle of the edge line of the hollow hole is determined according to the actual situation, and the angles such as 45°, 60°, and 90° can be selected.

[0055] S102, placing the metal film with the hollow hole shape drawn on it into an ultraviolet laser processing system, and cutting the metal film to obtain a stretchable heating circuit.

[0056] S103, connecting a wire on an opposite side of the stretchable heating circuit.

[0057] In this embodiment, the metal film is a Cu film, and the obtained stretchable heating circuit has excellent conductivity; the curve median diameter of the hollow hole edge line is 2.5 mm, and the line width is 1 mm. The above dimensions can be adjusted according to actual needs.

[0058] S200, preparing a stretchable thermal sensing module array layer:

[0059] S201, drawing a curved wire shape on a metal film.

[0060] S202, placing the metal film with the curved conductor shape drawn thereon into an ultraviolet laser processing system, and cutting the metal film to obtain the curved conductor.

[0061] S203, connecting the plurality of thermal sensing modules through curved wires to form a stretchable thermal sensing module array layer.

[0062] S300, package conformal heating film:

[0063] S301, aliphatic aromatic random copolyesters are prepared according to the ratio of A and B components in a ratio of 1:1, stirred evenly and degassed, and then poured into a mold and cured for 5-6 hours to obtain a flexible substrate of a certain thickness;

[0064] S302, pasting the stretchable heating circuit on the cured aliphatic aromatic random copolyester, pouring the aliphatic aromatic random copolyester again and curing it to form a heating circuit packaging layer, and the heating circuit packaging layer is sealed and connected to the flexible substrate after curing;

[0065] S303, pasting the stretchable thermal sensing module array layer on top of the cured heating circuit packaging layer; pouring aliphatic aromatic random copolyester for the third time and curing for 5-6 hours to form an upper packaging layer; demoulding and cutting to obtain a conformal heating film.

[0066] Specifically, in step S300, the aliphatic aromatic random copolyester material selected is Ecoflex00-30 produced by SMOOTH-ON.

[0067] Specifically, in step S302, when pasting the stretchable heating circuit, the stretchable heating circuit must be kept flat, and the end of the wire that is not connected to the stretchable heating circuit must be laid to the edge of the heating circuit packaging layer or outside the heating circuit packaging layer.

[0068] The flexible substrate, upper packaging layer and heating circuit packaging layer are all made of low-modulus and high-flexibility aliphatic aromatic random copolyester materials. On the one hand, they have excellent tensile properties and can support the overall tensile deformation of the conformal heating film; on the other hand, they have a uniform effect on the heat diffused from the wires and heating circuit positions.

[0069] In addition, in order to ensure that the thermal sensing module is located at the center of the hollow hole after the conformal heating film is prepared, step S203 can be performed simultaneously with step S300. First, the center of the hollow hole is determined on the side of the heating circuit packaging layer away from the stretchable heating circuit. Then, the thermal sensing module is pasted on the heating circuit packaging layer according to the determined position, and then multiple thermal sensing modules are connected together through curved wires.

[0070] In step S300, the size of the mold is 350×350 mm, the thickness of the flexible substrate and the upper packaging layer are both 1 mm, and the thickness of the heating circuit packaging layer is 0.5 mm. The above dimensions can be adjusted according to actual needs. For example, the thickness of the heating circuit packaging layer can also be 0.6 mm or 0.7 mm.

[0071] Specifically, in another embodiment of the present invention, in the preparation of the conformal heating film, in step S301, the aliphatic aromatic random copolyester is prepared according to A:B=1:3, stirred evenly and degassed, and then poured into a mold for curing for 6 hours to obtain a flexible substrate of a certain thickness. In step S303, the stretchable thermal sensing module array layer is pasted on top of the cured heating circuit packaging layer; the aliphatic aromatic random copolyester is poured in for the third time and cured for 6 hours to form an upper packaging layer; demolding and cutting are performed to obtain the conformal heating film.

[0072] In another embodiment of the present invention, in the preparation of the conformal heating film, in step S301, the aliphatic aromatic random copolyester is prepared according to A: B = 1: 1, stirred evenly and degassed, and then poured into a mold for curing for 5 hours to obtain a flexible substrate of a certain thickness. In step S303, the stretchable thermal sensing module array layer is pasted on top of the cured heating circuit packaging layer; the aliphatic aromatic random copolyester is poured in for the third time and cured for 5 hours to form an upper packaging layer; demolding and cutting are performed to obtain the conformal heating film.

[0073] In addition, in another embodiment of the present invention, there is provided an application of a conformal heating film in aerospace, transportation, transmission lines or heating clothing.

[0074] According to the embodiments of the present invention, through overall stretching, the conformal heating film with integrated temperature monitoring function can be applied to various complex curved surfaces, such as human body, pipeline, aircraft wing and clothing, to play the function of heating and monitoring temperature. Compared with the traditional heating and temperature monitoring method, the conformal heating film with integrated temperature monitoring function is more integrated and has a broader application prospect on complex curved surfaces.

[0075] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A conformal heating film, characterized in that: It comprises a stretchable flexible shell, wherein a stretchable thermal sensing module array layer, a heating circuit packaging layer and a stretchable heating circuit are sequentially arranged in the stretchable flexible shell, the stretchable thermal sensing module array layer and the stretchable heating circuit are respectively fixedly mounted on both sides of the heating circuit packaging layer, and the positive electrode and the negative electrode of the stretchable heating circuit respectively penetrate the stretchable flexible shell; The stretchable heating circuit is a metal film with a plurality of hollow holes, the hollow holes are arranged in an array, and the edge lines of the hollow holes are curves; The stretchable thermal sensing module array layer includes a plurality of thermal sensing modules arranged in an array, two adjacent thermal sensing modules are connected by a curved wire, and the thermal sensing module is located at the center of the hollow hole; the curved wire is an antisymmetric arc structure.

2. A conformal heating film according to claim 1, characterized in that: The stretchable flexible shell comprises a flexible substrate and an upper packaging layer, wherein the flexible substrate and the upper packaging layer are sealingly connected.

3. The conformal heating film according to claim 1, characterized in that: The lengths of the edge lines of the hollow holes are the same, and the lengths of the curved lines are the same.

4. The conformal heating film according to claim 1, characterized in that: The stretchable flexible housing and the heating circuit packaging layer are both made of Ecoflex.

5. A method for preparing a conformal heating film according to any one of claims 1 to 4, characterized in that: include: After the flexible insulating material is poured into the mold and cured, the stretchable heating circuit is pasted, and the flexible insulating material is poured in again and cured to form a heating circuit packaging layer; the stretchable thermal sensor module array layer is pasted on top of the cured heating circuit packaging layer; finally, the flexible insulating material is poured in and cured to complete the production of the stretchable flexible shell, and the mold is demolded to obtain a conformal heating film.

6. The method for preparing a conformal heating film according to claim 5, characterized in that: The flexible insulating material is Ecoflex, which is prepared according to the ratio of A and B components of 1:1, stirred evenly and degassed; the curing time of each layer of Ecoflex is 5-6 hours.

7. The method for preparing a conformal heating film according to claim 5, characterized in that: The thickness of the heating circuit packaging layer is 0.5-0.7 mm.

8. Use of the conformal heating film according to any one of claims 1 to 4 in aerospace, transportation, transmission lines or heating clothing.

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