WO2022142091A1 - Electrical heating coating for increasing efficiency of electrical energy utilization and temperature control, and method for preparation thereof - Google Patents

Abstract

Disclosed is an electrical heating coating for increasing the efficiency of electrical energy utilization and temperature control, said electrical heating coating comprising, in sequence: (1) a substrate; (2) an Al2O 3 thin film layer; (3) a circuit layer (comprising a metallic copper coating and an integrated circuit layer). Also provided by the present invention is a preparation method based on the described electrical heating coating, comprising: (a) inspecting and surface pre-treating a substrate; (b) aluminizing the surface of the substrate; (c) converting the surface aluminum to Al2O 3 film; (d) depositing a copper coating on the Al2O 3 film using a cold spraying technique and then annealing; (e) after the annealing of step (d), eroding out a desired copper circuit; (f) soldering sensors and other electronic components in designated areas of the electrically heated coating and then packaging. The electric heating coating described in the present invention has a coating heating function, and, by means of the integration of a control circuit, is capable of good temperature monitoring, regulation, and other functions; high-power electronic components can also be integrated, improving the stability of electronic components and also improving the efficiency of thermal energy utilization.

Description

A kind of electric heating coating for improving electric energy utilization efficiency and temperature control and preparation method thereof technical field

The invention relates to the technical field of electric heating coatings, and more particularly, to an electric heating coating which improves the utilization efficiency of electric energy and temperature control and a preparation method thereof.

Background technique

With the continuous development and popularization of hybrid and electric vehicles, the role of electric heaters has become increasingly prominent. Electric heaters have higher requirements mainly in terms of heating efficiency, quality and size, cost and safety. The current mainstream electric heating technologies are mainly wire wound resistance heating technology and positive temperature coefficient heating technology. However, the electric heating efficiency of these two technologies needs to be improved, and the size and quality need to be further reduced. Defects such as slow response time. It is precisely because the mainstream electric heating technology has major defects that gave birth to the emergence of thermal layer technology.

For example, an electric heating anti-icing coating and its preparation method (application number 201610489651.0), an electric heating technology for aircraft anti-icing/de-icing (application number 201710248415.4), etc. all provide multilayer electric heating coatings system; a novel electric heating coating and its preparation method (application number 201910940041.1) also discloses a 3-layer structure electric heating coating system. However, these technologies only involve how to realize the thermal layer technology, that is, how to design the coating to achieve the purpose of heating; they do not involve the more important practical problems such as how to control the temperature and how to use the electric energy more effectively.

On the other hand, the current related technologies in the field of electric heating (including those related to electric vehicles) are developing in the direction of light weight, high efficiency, intelligence and integration. How to achieve this from a more macro and practical level? Electric heating technology is particularly urgent.

In view of this, the present invention not only proposes a preparation technology of electric heating coating, but also proposes a design idea considering how to control the temperature and how to use electric energy more effectively from the perspective of integration and intelligence.

technical problem

The purpose of the present invention is to provide a preparation method of an electric heating coating, which is a brand-new design idea, takes the realization of thermal layer technology as the basic function, has core functions such as temperature monitoring and regulation, and can integrate high-power electronic components at the same time. The device can improve the utilization efficiency of thermal energy while improving the stability of electronic components. Applicable to fields including but not limited to automobiles, high-speed rail, aviation and new energy.

technical solutions

In order to achieve this object of the invention, the present invention adopts the following technical solutions:

An electric heating coating for improving electric energy utilization efficiency and temperature control, the electric heating coating sequentially comprises:

1) Substrate;

2) Al ₂ O ₃ thin film layer;

3) Circuit layer.

Optionally, the thickness of the Al ₂ O ₃ thin film layer is 2-15 μm.

Optionally, the circuit layer includes a metallic copper coating and an integrated circuit layer. Preferably, the thickness of the metallic copper coating is 10-1000 μm, most preferably 10-100 μm.

The preparation method and design idea of electric heating coating based on improving electric energy utilization efficiency and temperature control are as follows:

a) Use the naked eye, optical microscope sampling and other means to inspect the substrate to confirm that the equipment is free of defects such as holes and inclusions. According to the specific conditions of the substrate, one or more of flame burning, alcohol cleaning, and acetone cleaning are used. way to remove oil.

b) Use magnetron sputtering and other methods to carry out aluminizing treatment on the surface of the substrate.

Optionally, if the substrate itself is Al or Al alloy, this step can be omitted;

Optionally, the thickness of the aluminized layer is 2-20 μm.

c) A layer of Al ₂ O ₃ film is formed on the surface of the substrate by anodic oxidation.

Optionally, the Al ₂ O ₃ layer can also be obtained by thermal spraying, chemical deposition and other methods, and the optimum thickness thereof depends on the usage.

Optionally, the Al ₂ O ₃ film can also be replaced by insulating substances such as resin, glass, and organic film, and the optimal thickness of the film depends on the usage.

d) Continue to deposit copper coating on the surface of Al ₂ O ₃ film by cold spraying technology, and then anneal.

Optionally, the thickness of the copper coating is matched with the designed power of the electric heater, usually 10-1000 μm; preferably, the thickness of the copper coating is 10-100 μm.

Optionally, the annealing treatment temperature is about 400°C, and 350-450°C is acceptable.

e) A copper circuit with the copper coating etched into the desired characteristic circuit by a certain method.

Optionally, the etching method includes, but is not limited to, electrochemical etching, etching, and the like.

In particular, the above step e) can also be achieved by the following methods: before performing step d), according to the shape of the required copper circuit, by designing a corresponding fixture or adding a certain protective layer on the surface of the ceramic coating, so that step d) Directly deposit copper circuits in the desired specific shape without re-etching.

f) According to the actual function and design of the electric heater, the sensor and other electronic components are welded in the designated area of the electric heating coating and properly packaged to obtain the integrated circuit layer.

Optionally, this step is to provide a design idea without limiting the specific implementation approach;

Optionally, any number of designated areas can be set on the coating surface, depending on the actual function and design of the electric heater;

Optionally, the designated area can be located at any position on the entire coating surface, and its size and shape are also not fixed, which also depends on the actual function and design of the electric heater.

The embodiment of the present invention also provides an electric heating coating, which is obtained based on any of the above-mentioned preparation methods or design ideas.

beneficial effect

Based on the electric heating coating provided by the present invention, better temperature control can be achieved after integrating the control circuit, and the utilization rate of electric energy can be greatly improved by using the overall design of the integrated circuit layer and using the copper conductive layer material with lower resistance.

Description of drawings

Figure 1 is a schematic diagram of the electric heating coating provided by the present invention. Among them, 1-coolant, ₂ -Al substrate, 3- _Al2O3 film, 4-copper circuit, 5-high power device, 6-sensor.

FIG. 2 is a schematic diagram of another electric heating coating provided by the present invention. Among them, 1''- coolant, 2'- stainless steel substrate, 3'- aluminized film, 4'- Al ₂ O ₃ film, 5'- copper circuit, 6'- sensor.

FIG. 3 is a schematic diagram of another electric heating coating provided by the present invention. Among them, 1"-coolant, 2"-Al alloy substrate, 3"-Al ₂ O ₃ film, 4"- copper circuit, 5"- sensor.

BEST MODE FOR CARRYING OUT THE INVENTION

In order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not indicated in the examples, it is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used without the manufacturer's indication are conventional products that can be purchased from the market.

The preparation method and design idea of an electric heating coating provided by the present invention will be specifically described below.

The first thing to point out is that the thermal layer technology that has emerged in recent years is completely different from the traditional wire wound resistance heating technology and positive temperature coefficient heating technology in terms of heating principles and methods. There are significant advantages in terms of time and other aspects, so the traditional wire wound resistance heating technology and the positive temperature coefficient heating technology will not be specifically compared with the technology of the present invention.

Secondly, the inventor found that the thermal layer technology has also been disclosed to a certain extent in recent years. However, the current related technologies in the field of electric heating (including electric vehicle related technologies) are all moving towards lightweight, high-efficiency, intelligence and integration. It is very important to design and manufacture electric heating coatings with higher performance and more integrated functions, and the present invention is based on this point of view, and provides a higher performance than the existing public reports. And more functional electric heating coating structure design, design ideas of preparation method. The invention adopts a large number of modern surface engineering technical means, involving vacuum coating, anodizing, cold spraying, integrated circuits and other fields. At the same time, it can integrate high-power electronic components, improve the stability of electronic components, and improve the utilization efficiency of thermal energy. It is expected that the applicable fields of this technology include but are not limited to fields such as automobiles, high-speed rail, aviation, and new energy.

Some embodiments of the present invention provide an electric heating coating and a preparation method and design idea thereof, which may specifically include:

a) Inspection and surface pretreatment of the substrate to confirm that there are no specific defects on the surface of the substrate, and clean the surface of the substrate.

Use naked eyes, optical microscope sampling and other means to inspect the substrate to confirm that the equipment is free of defects such as holes and inclusions. According to the specific conditions of the substrate, one or more methods of flame burning, alcohol cleaning, and acetone cleaning are used to carry out Oil removal treatment.

The above are some conventional pretreatments performed on the substrate, and their uses will not be described in detail here.

b) Use magnetron sputtering and other methods to perform aluminizing treatment on the surface of the substrate. If the substrate itself is Al or Al alloy, this step can be omitted.

In some preferred implementation methods, Al or Al alloy is selected as the base material, which can omit the process of magnetron sputtering, thereby simplifying the process and reducing the cost; of course, the base material can also be metals of other materials, or even ceramics , composite materials, etc., then it is necessary to use magnetron sputtering to coat a layer of aluminum on the surface of the substrate. Preferably, the thickness of the aluminum coating layer is 2-20 μm.

c) A layer of Al ₂ O ₃ film is formed on the surface of the substrate by anodic oxidation.

In some preferred embodiments, a layer of Al ₂ O ₃ film is formed on the surface of an Al/Al alloy substrate or aluminized substrate by anodizing method, which is formed by (magnetron sputtering aluminum plating +) anodizing. The Al ₂ O ₃ film is a gradient film whose composition is gradually changed from Al ₂ O ₃ to Al/Al alloy. The higher thermal efficiency can improve the efficiency of the electric heating coating using electric energy, and at the same time improve the thermal response speed of the coating. Preferably, the thickness of the Al ₂ O ₃ film is 2-15 μm.

In some preferred implementation methods, the Al ₂ O ₃ layer can also be deposited on the surface of the substrate by thermal spraying, chemical deposition, etc., but the Al ₂ O ₃ film obtained by anodizing is more compact and thicker Therefore, it has better insulation and thermal conductivity; however, if under special requirements, such as when the thickness of the Al ₂ O ₃ film is required to be thicker, or the requirements for the insulation and thermal conductivity of the Al ₂ O ₃ film are not strict , other methods can be considered to deposit the Al ₂ O ₃ layer on the surface of the substrate.

In some preferred implementation methods, if the requirements for insulation and thermal conductivity are not high, the Al ₂ O ₃ film can also be replaced by insulating substances such as resin, glass, and organic thin films, although these insulating substances are often insufficient in high temperature resistance. , and the insulation and thermal conductivity are not good, but the use of these substances to replace the Al ₂ O ₃ film can often reduce the cost, so it is also possible to use.

d) A dense copper coating is then deposited on the above surface by cold spraying technology, and the electrical properties of the copper coating are improved by annealing treatment.

In some preferred embodiments, the copper coating obtained by depositing copper by cold spraying and annealing is used as the electric heating layer. This is because copper itself is a metal with good electrical conductivity and is relatively inexpensive. On the other hand, the copper coating obtained by cold spraying and annealing treatment is dense (porosity <0.5%), which can have comparable conductivity to as-cast copper, resulting in extremely low resistance (several orders of magnitude difference from the comparison technology) . From electrical knowledge, we know that under the same voltage, the lower the resistance, the greater the power. This means that under voltage-limited application scenarios such as automobiles and aviation aircraft, the electric heating coating of the present invention will have a much higher maximum electric heating power than the comparative technology; or, under the same output power, it will have Lower terminal pressure, and lower terminal pressure means less power loss during transmission. It can be seen that compared with other comparative examples (CN201610489651.0, CN201710248415.4, CN201910940041.1), the present invention has obvious advantages in increasing the maximum electric heating power and reducing electric energy loss.

e) Etch the copper coating to obtain the desired copper circuit.

In some preferred embodiments, chemical or electrochemical etching is used to achieve this.

It should be specially pointed out that here is only a method for obtaining copper circuits, but it is not limited to corrosion:

In some preferred embodiments, according to the shape of the copper circuit required, by designing a corresponding fixture or adding a certain protective layer on the surface of the ceramic coating before the cold spraying copper coating, during the cold spraying copper coating process The copper circuit of the required specific shape can be directly deposited without etching again;

In some preferred embodiments, non-corrosive means such as laser engraving may be considered to obtain copper circuits.

f) Solder sensors and other electronic components in the designated area of the electric heating coating and carry out appropriate packaging to obtain the integrated circuit layer.

The content contained in this step is actually a design idea, and is not limited to one or some specific specific implementations, and this purpose can only be achieved by proper cooperation with steps d) and e). This step is closely related to the design of the electric heater and the heat exchanger. According to the specific functions required by the electric heater and the heat exchanger, one or more groups of integrated circuits are designed, and then the electric heating coating of the present invention is applied. It is used as an insulating substrate for integrated circuits, giving more functions to the electric heating coating. The advantages of doing this are: 1. Improve the integration of the electric heater and the heat exchanger, thereby reducing the size and weight of the related structure; 2. Combine the electric heater and the heat exchanger into one, so that the heat exchanger can be combined The heat of the electric heater is used for electric heating, so that the electric power consumption of the electric heater can be greatly reduced under specific application methods, thereby greatly improving the electric-heat conversion efficiency. heating power for more stable and smooth temperature control. Of course, more functions related to electric heaters and heat exchangers can also be realized through appropriate integrated circuit design, and the present invention will not list them one by one here.

Some embodiments of the present invention also provide an electrically heated coating, obtained according to the preparation method and design idea provided in any of the above embodiments.

The features and performances of the present invention will be further described in detail below with reference to specific embodiments.

Example 1

a) Use the naked eye to inspect the Al substrate to see if the substrate has defects such as scratches, holes, and inclusions. Then use acetone to wipe off the oil stains on the surface of the above-mentioned Al substrate.

b) Considering that the substrate is an Al substrate, this step is omitted.

c) An Al ₂ O ₃ film with a thickness of 10 μm was oxidized on the surface of the Al substrate by anodization.

d) Using pure copper powder as the raw material powder, the copper coating was sprayed on the ceramic layer by cold spraying technology with a thickness of 10 μm, and then annealed at 400 °C;

e) the use of chemical etching to etch the copper coating into an electrical circuit with a specific shape;

f) Weld the sensor and other electronic components in the designated area of the electric heating coating and carry out appropriate packaging, as shown in Figure 1; that is.

Example 2

a) Use the naked eye to inspect the stainless steel substrate to see if the substrate has scratches, holes, inclusions and other defects. Then use acetone to wipe the oil stains on the surface of the stainless steel substrate.

b) The surface of the substrate is coated with an aluminum coating with a thickness of 15 μm by methods such as magnetron sputtering.

c) A 10 μm thick Al ₂ O ₃ film was oxidized on the aluminized film by anodization.

d) Using pure copper powder as the raw material powder, the copper coating was sprayed on the ceramic layer by cold spraying technology with a thickness of 10 μm, and then annealed at 400 °C;

e) the use of chemical etching to etch the copper coating into an electrical circuit with a specific shape;

f) Weld the sensor and other electronic components in the designated area of the electric heating coating and carry out appropriate packaging, as shown in Figure 2; that is.

Example 3

a) Use the naked eye to inspect the Al alloy substrate to see if the substrate has scratches, holes, inclusions and other defects. Then, use acetone to wipe the oil stains on the surface of the above-mentioned Al alloy substrate.

b) Considering that the substrate is an Al alloy substrate, this step is omitted.

c) An Al ₂ O ₃ film with a thickness of 10 μm was oxidized on the surface of the Al alloy substrate by anodization.

d) Using pure copper powder as the raw material powder, the copper coating was sprayed on the ceramic layer by cold spraying technology with a thickness of 10 μm, and then annealed at 400 °C;

e) The use of laser engraving to etch the copper coating into an electrical circuit with a specific shape;

f) Weld the sensor and other electronic components in the designated area of the electric heating coating and carry out appropriate packaging, as shown in Figure 3; that is.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims (10)

1. An electric heating coating for improving electric energy utilization efficiency and temperature control, characterized in that, the electric heating coating sequentially comprises:

   1) Substrate;

   2) Al ₂ O ₃ thin film layer;

   3) Circuit layer.
2. The electric heating coating for improving electric energy utilization efficiency and temperature control according to claim 1, characterized in that the thickness of the Al ₂ O ₃ thin film layer is 2-15 μm.
3. The electric heating coating for improving power utilization efficiency and temperature control according to claim 1, wherein the circuit layer comprises a metal copper coating and an integrated circuit layer.
4. The electric heating coating for improving electric energy utilization efficiency and temperature control according to claim 3, characterized in that the thickness of the metal copper coating is 10-1000 μm, preferably 10-100 μm.
5. A method for preparing an electric heating coating for improving electric energy utilization efficiency and temperature control according to claim 1, characterized in that, comprising:

   a) Inspection and surface pretreatment of the substrate to confirm that there are no specific defects on the surface of the substrate, and to clean the surface of the substrate;

   b) Magnetron sputtering is used to aluminize the surface of the substrate. If the substrate itself is Al or Al alloy, this step can be omitted;

   c) A layer of Al ₂ O ₃ film is formed on the surface of the substrate by anodic oxidation;

   d) A dense copper coating is then deposited on the above-mentioned surface by cold spray technology, and annealed;

   e) etching the copper coating to obtain the desired copper circuit;

   f) Solder sensors and other electronic components in designated areas of the electrically heated coating and encapsulate them.
6. The method for preparing an electric heating coating for improving power utilization efficiency and temperature control according to claim 5, wherein the inspection in step a) includes but is not limited to naked eye observation and optical microscope sampling observation; the specific defects include But not limited to holes and inclusions; the surface pretreatment is degreasing treatment.
7. The method for preparing an electric heating coating for improving electric energy utilization efficiency and temperature control according to claim 5, characterized in that, in step b), the thickness of the aluminized layer is 2-20 μm.
8. The method for preparing an electric heating coating for improving power utilization efficiency and temperature control according to claim 5, wherein the Al ₂ O ₃ film in step c) can also be obtained by thermal spraying or chemical deposition. Step b) can be omitted.
9. The method for preparing an electric heating coating for improving power utilization efficiency and temperature control according to claim 5, wherein the temperature of the annealing treatment in step d) is 350°C to 450°C.
10. The method for preparing an electric heating coating for improving power utilization efficiency and temperature control according to claim 5, characterized in that the etching method in step e) includes but is not limited to chemical etching.