Flexible electrothermal film structure and electrothermal device

Abstract

The application discloses a flexible electrothermal film structure and an electrothermal device, and relates to the technical field of electrothermal films, which comprises a flexible substrate, a flexible electrode arranged on the flexible substrate, an electrothermal composite material layer arranged on the flexible electrode, and an insulating and heat-conducting layer arranged on the electrothermal composite material layer, wherein the insulating and heat-conducting layer is a nano boron nitride film. The application is characterized in that the high-thermal-conductivity nano boron nitride film is arranged on the electrothermal composite material layer to realize insulation and heat conduction, prevent heat accumulation in the electrothermal composite material layer, and make the temperature of the electrothermal film more uniformly distributed.

Description

Technical Field

[0001] This utility model relates to the field of electrothermal film technology, specifically a flexible electrothermal film structure and electrothermal device. Background Technology

[0002] As a highly efficient, energy-saving, and easily integrated electrothermal conversion element, electrothermal film has been widely used in building heating (such as underfloor heating), physiotherapy and health care, automotive heating (seats, steering wheels, rearview mirrors), industrial special heating, defogging and defrosting, and other fields due to its advantages such as being thin, light, and flexible in design.

[0003] For example, patent CN117896859A discloses a flexible high-temperature graphene electrothermal film and its preparation method, which includes a substrate, metal wires, a conductive heating layer and a protective layer. The graphene electrothermal film prepared by it has excellent electrical conductivity and thermal conductivity.

[0004] For electrothermal films, core performance indicators include heat conversion efficiency, response speed, operating temperature range, safety, service life, and temperature distribution uniformity. Among these, temperature uniformity is crucial for the practical application of electrothermal films. Uneven temperature distribution can lead to a series of problems, such as decreased user comfort, reduced energy efficiency, material performance degradation, and safety hazards. In fact, prolonged exposure to excessively high temperatures in localized hot spots accelerates the aging, oxidation, and even ablation of the heating materials in those areas (such as conductive inks, carbon-based materials, and metal films), shortening the lifespan of the electrothermal film.

[0005] Therefore, temperature uniformity is one of the key bottlenecks restricting the improvement of electrothermal film performance and application. Thus, there is an urgent need to develop a flexible electrothermal film structure and electrothermal equipment to solve the problems in existing technologies. Utility Model Content

[0006] The purpose of this invention is to provide a flexible electrothermal film structure and electrothermal device, which solves the problem of poor temperature uniformity of existing electrothermal films mentioned in the background art by setting a nano boron nitride thin film on the electrothermal composite material layer.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A flexible electrothermal film structure, comprising:

[0009] Flexible substrate;

[0010] A flexible electrode, wherein the flexible electrode is disposed on the flexible substrate;

[0011] An electrothermal composite material layer is disposed on the flexible electrode;

[0012] An insulating and thermally conductive layer is disposed on the electrothermal composite material layer;

[0013] The insulating and thermally conductive layer is a nano-boron nitride thin film.

[0014] Furthermore, the thickness of the boron nitride nanofilm is 50 nanometers to 100 nanometers.

[0015] Furthermore, the boron nitride nanofilm has an aspect ratio greater than 1500 and a porosity greater than 80%.

[0016] Furthermore, the boron nitride nanofilm is a magnetron sputtered deposition film.

[0017] Furthermore, the flexible substrate includes a Teflon cloth layer, a PET material film layer, or an alkali-free glass fiber cloth layer.

[0018] Furthermore, the thickness of the flexible electrode is 2 micrometers to 5 micrometers, and the flexible electrode includes a conductive silver paste electrode, a silver nanowire electrode, or a copper nanowire electrode.

[0019] Furthermore, the insulating and thermally conductive layer is covered with a heat-insulating layer.

[0020] Furthermore, a heat-insulating protective layer is also provided on the lower surface of the substrate.

[0021] Furthermore, a surface protective layer is also provided on the insulation layer, which includes a polytetrafluoroethylene layer or a phenyl resin layer.

[0022] An electric heating device, comprising the aforementioned flexible electric heating film structure.

[0023] Compared with the prior art, the beneficial effects of this utility model are:

[0024] (1) By setting a high thermal conductivity nano boron nitride film on the electrothermal composite material layer for insulation and heat conduction, heat accumulation in the electrothermal composite material layer is prevented, and the temperature of the electrothermal film is more uniformly distributed.

[0025] (2) By setting nanoscale boron nitride thin films with an aspect ratio greater than 1500 and a porosity greater than 80%, the insulating and thermally conductive layer can maintain excellent insulation at high temperatures and has a certain degree of flexibility.

[0026] Other features and advantages of this utility model will be disclosed in detail in the following specific embodiments and accompanying drawings. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of this application;

[0028] Figure 2 These are the test data for the flexible electrothermal film of this application;

[0029] The markings in the diagram are as follows: 1. Surface protective layer; 2. Thermal insulation layer; 3. Insulating and thermally conductive layer; 4. Electrothermal composite material layer; 5. Flexible electrode; 6. Flexible substrate; 7. Thermal insulation protective layer. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0031] A flexible electrothermal film structure, such as Figure 1 As shown, it includes:

[0032] Flexible substrate 6;

[0033] Flexible electrode 5 is disposed on the flexible substrate 6;

[0034] An electrothermal composite material layer 4 is disposed on the flexible electrode 5;

[0035] An insulating and thermally conductive layer 3 is disposed on the electrothermal composite material layer 4;

[0036] The insulating and thermally conductive layer 3 is a nano-boron nitride thin film. The thickness of the nano-boron nitride thin film is 50 nm to 100 nm. The aspect ratio of the nano-boron nitride thin film is greater than 1500 and the porosity is greater than 80%.

[0037] This application achieves insulation and heat conduction by setting a high thermal conductivity boron nitride nanofilm on the electrothermal composite material layer 4, preventing heat accumulation in the electrothermal composite material layer 4 and making the temperature distribution of the electrothermal film more uniform. By setting a nanoscale boron nitride nanofilm with an aspect ratio greater than 1500 and a porosity greater than 80%, the insulating and heat-conducting layer 3 can maintain excellent insulation at high temperatures and also has a certain degree of flexibility.

[0038] In this embodiment, the boron nitride nanofilm is a magnetron sputtering deposited film, which is formed by magnetron sputtering on the electrothermal composite material layer 4, making the boron nitride nanofilm bonded more tightly with the electrothermal composite material layer 4, which helps to make the temperature of the electrothermal film more uniform.

[0039] The flexible substrate 6 includes a Teflon cloth layer, a PET material film layer, or an alkali-free glass fiber cloth layer, wherein the Teflon cloth layer, the PET material film layer, and the alkali-free glass fiber cloth layer are respectively composed of Teflon cloth, PET material film, and alkali-free glass fiber cloth.

[0040] The thickness of the flexible electrode 5 is 2 micrometers to 5 micrometers. The flexible electrode 5 includes a conductive silver paste electrode, a silver nanowire electrode, or a copper nanowire electrode, which are respectively composed of conductive silver paste, silver nanowires, and copper nanowires. These are existing technologies and will not be described in detail in this application.

[0041] The thickness of the electrothermal composite material layer 4 is 10-20 micrometers. The electrothermal composite material layer 4 is formed by coating the flexible electrode 5 with an electrothermal composite slurry. In this embodiment, the electrothermal composite slurry includes conductive fillers and auxiliary fillers, which are existing technologies and will not be described further in this application.

[0042] In this embodiment, the insulating and thermally conductive layer 3 is covered with a heat-insulating layer 2. A heat-insulating protective layer 7 is also provided on the lower surface of the substrate. A surface protective layer 1 is also provided on the heat-insulating layer 2. The surface protective layer 1 is a wear-resistant layer; in this embodiment, it is a polytetrafluoroethylene layer or a phenyl resin layer.

[0043] An electric heating device, comprising the aforementioned flexible electric heating film structure.

[0044] Standards for measuring the temperature uniformity of electric heating films include the temperature standard deviation σ and the uniformity index UI.

[0045] The formula for calculating the uniformity index UI is as follows:

[0046] UI=1-σ / T

[0047] Where T is the average temperature, and generally, UI > 0.95.

[0048] like Figure 2 As shown, test data for a flexible electrothermal film using the insulating and thermally conductive layer 3 of this application is provided. A temperature distribution map is generated by scanning the surface of the flexible electrothermal film using an infrared thermal imager inside a sealed constant temperature chamber. The ambient temperature fluctuation is controlled within ±1℃, and the humidity is controlled within 40-60%RH.

[0049] like Figure 2 The figure shows the temperature data of 10 points P1-P10 when the product of this application was used. The average temperature was 114.84℃, the temperature standard deviation was 0.591, and the uniformity index was 0.995.

[0050] A method for preparing a flexible electrothermal film structure includes:

[0051] A flexible substrate 6 is provided, wherein the flexible substrate 6 is one of Teflon cloth, PET material film or alkali-free glass fiber cloth;

[0052] The flexible electrode 5 is uniformly coated on the flexible substrate 6 by screen printing; wherein the material of the flexible electrode 5 includes any one of conductive silver paste, silver nanowires, and copper nanowires, and the thickness is 2 micrometers-5 micrometers.

[0053] An electrothermal composite slurry is coated onto the flexible electrode 5 using a mask to form an electrothermal composite material layer 4. The electrothermal composite slurry includes conductive fillers and auxiliary fillers. The conductive material includes one or more of conductive carbon black, graphite, graphene, or carbon fiber, and the auxiliary filler includes one of alumina or silicon dioxide. The conductive filler and auxiliary filler are mixed with an organic solvent to form the electrothermal composite slurry. The thickness of the electrothermal composite material layer 4 is 10 micrometers to 20 micrometers.

[0054] A nano-boron nitride thin film is deposited on the cured electrothermal composite material layer 4 by magnetron sputtering to form an insulating and thermally conductive layer 3.

[0055] In this embodiment, the method for preparing the flexible electrothermal film structure further includes:

[0056] A heat insulation layer 2 is covered on the insulating and heat-conducting layer 3 to prevent rapid heat loss. The heat insulation layer 2 is made of either polyurethane or polyethylene.

[0057] A surface protective layer 1 is added to the insulation layer 2 to increase the wear resistance of the electrothermal film. The protective layer can be any one of polytetrafluoroethylene or phenyl resin.

[0058] A heat insulation protective layer 7 is added to the back of the substrate to provide heat insulation protection.

[0059] This utility model provides a flexible electrothermal film structure and electrothermal device, which is simple in structure, easy to use, and highly reliable.

[0060] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A flexible electrothermal film structure, characterized in that, include: Flexible substrate; A flexible electrode, wherein the flexible electrode is disposed on the flexible substrate; An electrothermal composite material layer is disposed on the flexible electrode; An insulating and thermally conductive layer is disposed on the electrothermal composite material layer; The insulating and thermally conductive layer is a nano-boron nitride thin film.

2. The flexible electrothermal film structure according to claim 1, characterized in that, The thickness of the boron nitride nanofilm is 50 nanometers to 100 nanometers.

3. The flexible electrothermal film structure according to claim 1 or 2, characterized in that, The boron nitride nanofilm has an aspect ratio greater than 1500 and a porosity greater than 80%.

4. The flexible electrothermal film structure according to claim 3, characterized in that, The boron nitride nanofilm is a magnetron sputtered deposition film.

5. The flexible electrothermal film structure according to claim 4, characterized in that, The flexible substrate includes a Teflon cloth layer, a PET material film layer, or an alkali-free glass fiber cloth layer.

6. The flexible electrothermal film structure according to claim 4, characterized in that, The thickness of the flexible electrode is 2 micrometers to 5 micrometers, and the flexible electrode includes a conductive silver paste electrode, a silver nanowire electrode, or a copper nanowire electrode.

7. The flexible electrothermal film structure according to any one of claims 4-6, characterized in that, The insulating and thermally conductive layer is covered with a heat-insulating layer.

8. The flexible electrothermal film structure according to claim 7, characterized in that, A heat-insulating protective layer is also provided on the lower surface of the substrate.

9. The flexible electrothermal film structure according to claim 7, characterized in that, The insulation layer is further provided with a surface protective layer, which includes a polytetrafluoroethylene layer or a phenyl resin layer.

10. An electric heating device, characterized in that, Includes the flexible electrothermal film structure as described in any one of claims 1-9.

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