Heating film and preparation method therefor, heating tube, and heating appliance

Abstract

The present disclosure provides a heating film and a preparation method therefor, a heating element, and a heating appliance. Raw materials of the heating film include natural graphite and / or graphene; and the heating film meets at least one of the following conditions: the thickness of the heating film is 0.04 mm to 2 mm, and the density of the heating film is 0.6 g / cm3 to 1.8 g / cm3.

Description

Heating diaphragm and preparation method thereof, heating tube and heating appliance

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims the priority benefit of Chinese patent application No. 202410119728.X filed on January 26, 2024, and incorporates the entirety of the application into this document. Technical Field

[0003] The present disclosure relates to the field of electrical appliance technology, and more specifically, to a heating diaphragm and a preparation method thereof, a heating tube, and a heating appliance. Background Art

[0004] Traditional electric ovens mainly heat the air in the cavity through heating tubes to heat the food, and directly heat the surface of the food through heat radiation. The heating components used in electric ovens, microwave ovens, steam ovens and other heating appliances on the market currently mainly include metal heating tubes (maximum heating temperature range between 550 and 750 ° C), quartz heating tubes (heating wire temperature range between 660 and 800 ° C), halogen heating tubes (maximum heating temperature less than 1000 ° C) and carbon fiber heating tubes (maximum heating temperature less than 1000 ° C). However, the above heating tubes have problems such as low heating rate within the heating temperature range, insufficient heating speed, and insufficient temperature. These problems prolong the cooking time and make it difficult to achieve crispy outside and tender inside food during the heating process, resulting in a poor user experience. In addition, the power adjustable range of current heating tubes is relatively small, which limits their scope of application.

[0005] Summary of the Invention

[0006] The present disclosure aims to solve one of the technical problems in the related art to at least a certain extent. To this end, one purpose of the present disclosure is to provide a heating film having the advantages of high heating temperature, fast heating speed, and fast temperature rise speed.

[0007] In one aspect of the present disclosure, a heating film is provided. According to an embodiment of the present disclosure, the raw material of the heating film includes natural graphite and / or graphene, and the heating film satisfies at least one of the following conditions: the thickness of the heating film is 0.04 mm to 2 mm; the density of the heating film is 0.6 g / cm 3 ~1.8g / cm 3. Thus, the heating diaphragm made of graphite material prepared by using natural graphite or graphene makes the heating temperature of the heating diaphragm higher and the heating rate faster, which helps to achieve higher temperature heating and higher heating efficiency; moreover, the heating diaphragm disclosed in the present invention uses natural graphite, and natural graphite ore has large reserves among the earth's minerals. At the same time, the carbon-based diaphragm material does not require high-temperature graphitization during the preparation process, and does not need to be prepared by other processes, and can be produced continuously to reduce costs. In general, the carbon-based diaphragm material has the advantages of a wide source of raw materials, a simple preparation process, good product stability, and performance parameters that can be adjusted according to demand and easy to adjust. It has huge advantages in reducing product costs, enhancing product reliability, and enriching product types. If artificial graphite is used, it is necessary to further set up a process flow for making artificial graphite, which will greatly increase the production cost and time of the heating diaphragm and reduce production efficiency; using graphene as a raw material is conducive to obtaining a heating diaphragm with a higher carbon content, and the processing technology is simple and mature, and the preparation cost is not high. Furthermore, when the above-mentioned heating diaphragm meets the above-mentioned conditions, the heating diaphragm can meet a wider range of power requirements, and both a high-power heating diaphragm and a high-efficiency heating diaphragm can be obtained. At the same time, the heating diaphragm under the above-mentioned conditions has better manufacturability, that is, the production yield is higher, and the service life can meet the use requirements.

[0008] According to an embodiment of the present disclosure, the carbon content of the heating film is greater than or equal to 99%.

[0009] According to an embodiment of the present disclosure, the power of the heating film is 15W to 10000W.

[0010] According to an embodiment of the present disclosure, the heating film satisfies at least one of the following conditions: the length of the heating film is 250 mm to 450 mm, the width is 6 mm to 10 mm, and the density of the heating film is 1.2 g / cm 3 ~1.8g / cm 3 The power of the heating film is 30W~5000W; the length of the heating film is 450mm~650mm, the width is 6mm~10mm, and the density of the heating film is 1.2g / cm 3 ~1.8g / cm 3 The power of the heating film is 25W~10000W; the length of the heating film is 250mm~450mm, the width is 6mm~10mm, and the density of the heating film is 0.6g / cm 3 ~1.2g / cm 3 The power of the heating film is 10W~3400W; the length of the heating film is 450mm~650mm, the width is 6mm~10mm, and the density of the heating film is 0.6g / cm3 ~1.2g / cm 3 The power of the heating film is 10W to 7000W.

[0011] According to an embodiment of the present disclosure, the heating diaphragm has a sheet-like structure, the natural graphite and the graphene have a sheet-like structure, and the sheet-like extension plane of the heating diaphragm is substantially consistent with the sheet-like extension plane of the natural graphite and / or the graphene.

[0012] According to an embodiment of the present disclosure, the heating temperature of the heating film is 500°C to 1700°C.

[0013] According to an embodiment of the present disclosure, the heating film is made of graphite.

[0014] According to an embodiment of the present disclosure, the heating film includes a plurality of heating units sequentially arranged along the length direction, and adjacent heating units are arranged at intervals and connected by connecting sections.

[0015] According to an embodiment of the present disclosure, each of the heating units is provided with a hollow hole.

[0016] According to an embodiment of the present disclosure, the heating diaphragm includes a first heating segment and a second heating segment adjacent to each other in the length direction, the first heating segment includes a plurality of connected heating units, the second heating segment includes a plurality of adjacent heating units, the size of the heating unit corresponding to the first heating segment is smaller than the size of the heating unit corresponding to the second heating segment; and / or, the first heating segment and the second heating segment are staggered in the width direction of the heating diaphragm.

[0017] According to an embodiment of the present disclosure, the heating membrane includes a plurality of notches arranged at intervals along the length direction.

[0018] According to an embodiment of the present disclosure, each of the gaps is defined by separating a portion of the heating membrane from the rest and then bending it.

[0019] In another aspect of the present disclosure, the present disclosure provides a method for preparing the aforementioned heating film. According to an embodiment of the present disclosure, the method for preparing the heating film includes: providing natural graphite and performing an intercalation treatment on the natural graphite to obtain expandable graphite; performing an expansion treatment on the expandable graphite to obtain expanded graphite; performing calendaring, a first heat treatment, and cutting the expanded graphite to obtain the heating film, or the method for preparing the heating film includes: mixing and dispersing the graphene and additives uniformly to obtain a dispersion; applying the dispersion to obtain a dispersion film; performing a second heat treatment on the dispersion film to obtain a carbon-based primary film; and calendaring and cutting the carbon-based primary film to obtain the heating film. Thus, the heating diaphragm made of graphite material obtained by using natural graphite or graphene makes the heating temperature of the heating diaphragm higher and the heating rate faster, which helps to achieve higher temperature heating and higher heating efficiency; moreover, the heating diaphragm disclosed in the present invention uses natural graphite, and natural graphite ore has large reserves among the earth's minerals. At the same time, the carbon-based diaphragm material does not require high-temperature graphitization during the preparation process, does not need to be prepared by other processes, and can be produced continuously, reducing costs. In summary, the carbon-based diaphragm material has the advantages of a wide source of raw materials, simple preparation process, good product stability, and performance parameters that can be adjusted and easily adjusted according to demand. It has huge advantages in reducing product costs, enhancing product reliability, and enriching product varieties. If artificial graphite is used, it is necessary to further set up a process flow for making artificial graphite, which will greatly increase the production cost and time of the heating diaphragm and reduce production efficiency; using graphene as a raw material is not only conducive to obtaining a heating diaphragm with a higher carbon content, but also has a simple and mature processing technology and low preparation cost.

[0020] According to an embodiment of the present disclosure, the intercalation treatment conditions are: intercalating the natural graphite with concentrated sulfuric acid and / or hydrogen peroxide to obtain the expandable graphite; the expansion treatment conditions are: putting the expandable graphite into an expansion furnace and expanding it at a temperature of 850-1200°C to obtain the expandable graphite.

[0021] In another aspect of the present disclosure, a heat pipe is provided. According to an embodiment of the present disclosure, the heat pipe includes the aforementioned heating film. As a result, the heat pipe achieves a higher heating temperature, a faster heating rate, and a more concentrated heating area, significantly improving the heating efficiency of the heat pipe. Those skilled in the art will appreciate that the heat pipe possesses all the features and advantages of the aforementioned heating film, and further details will not be given here.

[0022] In another aspect of the present disclosure, a heating appliance is provided. According to an embodiment of the present disclosure, the heating appliance includes the aforementioned heating pipe. As a result, the heating appliance has a higher heating temperature, a faster heating rate, and a more concentrated heating area, greatly improving the heating efficiency of the heating appliance.

[0023] According to an embodiment of the present disclosure, the heating appliance is an electric oven, a microwave oven, a steam oven, an electric kettle, an electric blanket, an electric fan heater, an electric heater, a bathroom heater, an electric ceramic stove or a disinfection cabinet. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present disclosure will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0025] FIG1 is a schematic diagram of heat radiation of a heating film disclosed in the present invention;

[0026] FIG2 is a schematic diagram of heat radiation of a heat-generating tube core in the prior art;

[0027] FIG3 is a schematic diagram of a curve showing the relationship between the heating temperature and the resistance of the heating film disclosed in the present invention;

[0028] FIG4 is a schematic diagram of a curve showing the relationship between thickness and resistance of the heating film disclosed herein;

[0029] FIG5 is a schematic structural diagram of a heating membrane in an embodiment of the present disclosure;

[0030] FIG6 is a schematic structural diagram of a heating film in other embodiments of the present disclosure;

[0031] FIG7 is a schematic structural diagram of a heating film in other embodiments of the present disclosure;

[0032] FIG8 is a schematic structural diagram of a heating pipe in some other embodiments of the present disclosure;

[0033] FIG9 is a schematic structural diagram of a heating pipe in some other embodiments of the present disclosure;

[0034] FIG10 is a schematic structural diagram of a heating pipe in some other embodiments of the present disclosure;

[0035] FIG11 is a schematic structural diagram of a heating film in other embodiments of the present disclosure. DETAILED DESCRIPTION

[0036] The scheme of the present disclosure will be explained below in conjunction with the examples. Those skilled in the art will understand that the following examples are only used to illustrate the present disclosure and should not be considered to limit the scope of the present disclosure. Where specific techniques or conditions are not specified in the examples, they are carried out according to the techniques or conditions described in the literature in this area or according to the product instructions. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be obtained commercially.

[0037] The present disclosure is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present disclosure in any way.

[0038] In one aspect of the present disclosure, a heating film is provided. According to an embodiment of the present disclosure, the raw material of the heating film includes natural graphite and / or graphene, and the heating film satisfies at least one of the following conditions: the thickness of the heating film is 0.04 mm to 2 mm, for example, the thickness of the heating film is 0.04 mm, 0.08 mm, 0.1 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2.0 mm, etc.; the density of the heating film is 0.6 g / cm 3 ~1.8g / cm 3 For example, the density of the heating film is 0.6g / cm 3 , 0.8g / cm 3 , 1.0g / cm 3 , 1.2g / cm 3 , 1.4g / cm 3 , 1.5g / cm 3 , 1.6g / cm 3 , 1.8g / cm 3 Etc. Thus, the heating diaphragm made of graphite material prepared by using natural graphite or graphene makes the heating temperature of the heating diaphragm higher and the heating rate faster, which helps to achieve higher temperature heating and higher heating efficiency; moreover, the heating diaphragm disclosed in the present invention uses natural graphite, and natural graphite ore has large reserves among the earth's minerals. At the same time, the carbon-based diaphragm material does not require high-temperature graphitization during the preparation process, does not need to be prepared by other processes, and can be produced continuously to reduce costs. In general, the carbon-based diaphragm material has the advantages of a wide source of raw materials, a simple preparation process, good product stability, and performance parameters that can be adjusted according to demand and easy to adjust. It has huge advantages in reducing product costs, enhancing product reliability, and enriching product types. If artificial graphite is used, it is necessary to further set up a process flow for making artificial graphite, which will greatly increase the production cost and time of the heating diaphragm and reduce production efficiency; using graphene as a raw material is conducive to obtaining a heating diaphragm with a higher carbon content, and the processing technology is simple and mature, and the preparation cost is not high. Furthermore, when the above-mentioned heating diaphragm meets the above-mentioned conditions, the heating diaphragm can meet a wider range of power requirements, that is, by adjusting the thickness and density of the above-mentioned heating diaphragm, heating diaphragms with different power values ​​can be obtained, and both high-power heating diaphragms and high-efficiency heating diaphragms can be obtained. At the same time, the heating diaphragm under the above-mentioned conditions has better manufacturability, that is, the production yield is higher, and the service life can meet the use requirements.

[0039] In some embodiments of the present disclosure, the raw graphene material may be graphene nanoplatelets, which are ultrathin graphene layered stacks with more than 10 carbon layers and a thickness in the range of 5-100 nanometers. Graphene nanoplatelets have excellent thermal conductivity and tensile strength, thereby helping to improve the heating temperature and mechanical strength of the prepared heating film.

[0040] According to some embodiments of the present disclosure, the heating film has a sheet-like structure, and the raw materials for preparing the heating film, natural graphite and / or graphene, have a sheet-like structure, and the sheet-like extension plane of the heating film is substantially consistent with the sheet-like extension plane of the graphite and / or graphene. Therefore, as shown in Figure 1, when the sheet-like structure heating film 20 generates heat, the heat is mainly radiated in the direction perpendicular to the heating surface (i.e., the plane of the film), with strong directivity and more concentrated radiated heat, thereby better improving the heating efficiency and reducing heat loss. In the current prior art, referring to Figure 2, the heat radiation of the heating tube core 1 (such as a metal heating tube core or a quartz tube core) is evenly emitted in all directions, and the heat cannot be concentrated. This usually causes heat waste and reduces heating efficiency. Therefore, by comparison, it can be seen that the heat radiation direction of the heating film of the present disclosure is more concentrated, which can better heat the object to be heated in a targeted manner and improve heating efficiency. It should be noted that the above-mentioned "substantially consistent" means that the sheet-like extension plane of the heating film is roughly consistent with the sheet-like extension plane of the graphite and / or graphene, and does not require that the two are completely consistent or completely parallel.

[0041] According to some embodiments of the present disclosure, as described above, the material of the heating diaphragm prepared from the raw material natural graphite and / or graphene is graphite, which enables the heating diaphragm of the present disclosure to have a higher heating temperature and a faster heating rate. Among them, the prepared graphite still has a sheet structure, and the plane extension direction of the sheet structure is basically the same as the plane extension direction of the raw material natural graphite or graphene. Therefore, it can be said that the sheet extension plane of the heating diaphragm is basically the same as the sheet extension plane of the graphite material it is made of.

[0042] According to some embodiments of the present disclosure, the carbon content of the heating film is greater than or equal to 99%. Therefore, the carbon content of the heating film is higher, that is, the purity is higher, which is conducive to obtaining a heating film with better performance.

[0043] According to some embodiments of the present disclosure, the power of the heating diaphragm is 15W to 10000W, such as 15W, 20W, 40W, 50W, 70W, 100W, 150W, 300W, 500W, 800W, 1000W, 1500W, 3000W, 4500W, 5000W, 6000W, 7000W, 8000W, 9000W, 10000W, etc. Therefore, the heating diaphragm of the present disclosure can effectively achieve heating of different powers with a large span, and can achieve ultra-low power heating as well as ultra-high power heating, meeting the power usage requirements of the heating diaphragm under various application conditions.

[0044] According to some embodiments of the present disclosure, the heating film prepared by natural graphite and / or graphene microsheets also has the characteristic of self-limiting temperature. Specifically: with reference to FIG3 , the heating film has a critical temperature. When the temperature of the heating film is less than the critical temperature, the resistance of the heating film decreases as the temperature increases; when the temperature of the heating film is greater than the critical temperature, the resistance of the heating film increases as the temperature increases. It can be seen that the heating film of the present disclosure has the characteristic of self-limiting temperature. Specifically: in the initial stage of heating (i.e., when the temperature of the heating film is less than the critical temperature), the resistance of the heating film decreases as the temperature increases, and the current increases, so that the power of the heating film increases with the temperature increase, so in this stage, the heating film can heat up rapidly; when the heating temperature of the heating film reaches the critical temperature, the resistance of the heating film increases as the temperature increases, and the current decreases, so that the power of the heating film decreases as the temperature increases, so in this stage, the heating rate of the heating film begins to slow down, and slowly gradually reaches the maximum heating temperature of the heating film. The self-limiting temperature characteristic of the heating diaphragm described above can, on the one hand, accelerate the heating rate of the heating diaphragm in the temperature zone below the critical temperature, allowing the heating diaphragm to reach the target temperature as quickly as possible. On the other hand, when the temperature is above the critical temperature, it can reduce the problem of melting caused by the continuous increase in the heating temperature, thereby improving the reliability and stability of the heating diaphragm. It should be noted that Figure 3 is only a temperature-resistance curve diagram of the heating diaphragm in one embodiment, but the trend of this curve represents the temperature-resistance curve schematic diagram of the heating diaphragm of the present disclosure.

[0045] According to some embodiments of the present disclosure, referring to FIG4 , the resistance characteristics (equidensity) of the carbon-based heating film are: the resistance gradually decreases with increasing thickness; the greater the thickness, the smaller the resistance, and the smaller the thickness, the greater the resistance. Based on this, in the present disclosure, the above-mentioned heating films of various power sizes can be obtained under the above-mentioned density and thickness conditions. Furthermore, the heating films can also have different power sizes according to parameters such as different thicknesses, density stages, and different lengths of the heating films. Specifically:

[0046] According to some embodiments of the present disclosure, the thickness of the heating film is 0.04 mm to 2 mm, the length of the heating film is 250 mm to 450 mm (for example, 250 mm, 280 mm, 300 mm, 320 mm, 350 mm, 370 mm, 400 mm, 420 mm, 450 mm, etc.), the width is 6 mm to 10 mm (for example, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc.), and the density of the heating film is 1.2 g / cm 3 ~1.8g / cm 3 (For example, 1.2g / cm 3 , 1.3g / cm 3 , 1.4g / cm 3 , 1.5g / cm 3 , 1.6g / cm 3 , 1.7g / cm 3 , 1.8g / cm 3 The power of the heating diaphragm is 30W~5000W, such as 30W, 40W, 50W, 80W, 100W, 150W, 200W, 300W, 400W, 800W, 1000W, 1300W, 1500W, 1800W, 2000W, 2300W, 2500W, 2800W, 3000W, 3200W, 3500W, 3800W, 4000W, 4200W, 4500W, 4800W, 5000W, etc. The heating diaphragm under the above length, thickness and density conditions can have a power of 30W~5000W, and the appropriate heating temperature can be obtained by adjusting the power to obtain a heating diaphragm that meets the needs.

[0047] According to some embodiments of the present disclosure, the thickness of the heating film is 0.04 mm to 2 mm, the length of the heating film is 450 mm to 650 mm (such as 450 mm, 500 mm, 520 mm, 550 mm, 580 mm, 600 mm, 630 mm, 650 mm, etc.), the width is 6 mm to 10 mm (such as 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc.), and the density of the heating film is 1.2 g / cm 3 ~1.8g / cm 3 (For example, 1.2g / cm 3 , 1.3g / cm 3 , 1.4g / cm 3 , 1.5g / cm 3 , 1.6g / cm 3 , 1.7g / cm 3 , 1.8g / cm 3etc.), the power of the heating diaphragm is 25W~10000W, for example, the power is 25W, 30W, 40W, 50W, 60W, 70W, 100W, 150W, 300W, 500W, 800W, 1000W, 1500W, 3000W, 4500W, 5000W, 6000W, 7000W, 8000W, 9000W, 10000W, etc. The heating diaphragm under the above length, thickness and density conditions can have a power of 25W~5000W, and the appropriate heating temperature can be obtained by adjusting the power to obtain a heating diaphragm that meets the needs.

[0048] According to some embodiments of the present disclosure, the thickness of the heating film is 0.04 mm to 2 mm, the length of the heating film is 250 mm to 450 mm, the width is 6 mm to 10 mm, and the density of the heating film is 0.6 g / cm 3 ~1.2g / cm 3 (For example, 0.6g / cm 3 , 0.7g / cm 3 , 0.8g / cm 3 , 0.9g / cm 3 , 1.0g / cm 3 , 1.1g / cm 3 , 1.2g / cm 3 The power of the heating film is 10W to 3400W. For example, the power can be 10W, 15W, 20W, 40W, 50W, 70W, 100W, 150W, 300W, 500W, 800W, 1000W, 1500W, 3000W, 3400W, etc. The heating film under the above length, thickness and density conditions can have a power of 10W to 5000W, and the appropriate heating temperature can be obtained by adjusting the power to obtain a heating film that meets the needs.

[0049] According to some embodiments of the present disclosure, the thickness of the heating film is 0.04 mm to 2 mm, the length of the heating film is 450 mm to 650 mm, the width is 6 mm to 10 mm, and the density of the heating film is 0.6 g / cm 3 ~1.2g / cm 3 (For example, 0.6g / cm 3 , 0.7g / cm 3 , 0.8g / cm 3 , 0.9g / cm 3 , 1.0g / cm 3 , 1.1g / cm 3 , 1.2g / cm 3The power of the heating film is 10W~7000W, for example, the power can be 10W, 20W, 40W, 50W, 70W, 100W, 150W, 300W, 500W, 800W, 1000W, 1500W, 3000W, 3400W, 4000W, 4500W, 5000W, 5400W, 6000W, 6500W, 7000W, etc. The heating film under the above length, thickness and density conditions can have a power of 10W~7000W, and the appropriate heating temperature can be obtained by adjusting the power to obtain a heating film that meets the needs.

[0050] According to some embodiments of the present disclosure, the thermal diffusion coefficient of the heating film is 50m 2 / s~450m 2 / s, for example, 50m 2 / s、80m 2 / s、100m 2 / s、130m 2 / s、150m 2 / s、280m 2 / s、300m 2 / s、320m 2 / s、350m 2 / s、370m 2 / s、400m 2 / s、420m 2 / s、450m 2 / s, etc. The above thermal diffusion coefficient can transfer the heat of the heating diaphragm to the heating chamber at a more appropriate rate, so that the heat generated by the heating diaphragm is mainly concentrated on the object to be heated. In this way, a better heating rate can be guaranteed without causing the heat to be transferred out too quickly, resulting in a large heat loss. In addition, the above thermal diffusion coefficient also helps to extend the service life of the heating diaphragm and improve the manufacturability of the heating diaphragm.

[0051] According to some embodiments of the present disclosure, the heating temperature of the heating film is 500°C to 1700°C. For example, the heating temperature of the heating film can be 500°C, 550°C, 600°C, 700°C, 800°C, 900°C, 1000°C, 1100°C, 1200°C, 1300°C, 1400°C, 1500°C, 1600°C, 1700°C, etc. It can be seen that the heating temperature of the heating film of the present disclosure can reach up to 1700°C. Moreover, those skilled in the art can flexibly adjust the maximum heating temperature of the heating film by adjusting the density and / or thickness of the heating film according to the specific application requirements of the heating film, thereby meeting more application heating requirements of the heating film and obtaining heating films of various powers, such as ultra-low power heating films or ultra-high power heating films.

[0052] In the embodiments of the present disclosure, the specific cutting shape of the heating film can be diversified. Those skilled in the art can flexibly design the cutting shape of the heating film according to the actual requirements of the resistance, power, etc. of the heating film. The following is an introduction to some cutting shapes of the heating film based on some specific embodiments of the present disclosure:

[0053] In some embodiments of the present disclosure, referring to FIG5 , the heating film includes a plurality of heating units 01 arranged sequentially along the length direction, with adjacent heating units 01 spaced apart and connected by connecting sections 02 . Thus, the heating film of the present disclosure can be cut into a variety of different cut-out structures to meet different usage requirements. Specifically, in some embodiments of the present disclosure, referring to FIG5 , the outer peripheral wall of the heating unit is formed into an oblong or polygonal shape.

[0054] In some embodiments of the present disclosure, referring to (b), (c), and (i) of FIG5 , each heating unit 01 is provided with a hollow hole 03. Thus, the provision of the hollow hole can accelerate the heat dissipation rate of the heating membrane and accelerate the heating rate of the object to be heated.

[0055] In some embodiments of the present disclosure, referring to FIG6 , the heating diaphragm includes a first heating segment S2 and a second heating segment S1 adjacent to each other in the length direction, the first heating segment S2 includes a plurality of connected heating units 01, the second heating segment S1 includes a plurality of adjacent heating units 01, the size of the heating unit 01 corresponding to the first heating segment S2 is smaller than the size of the heating unit 01 corresponding to the second heating segment S1, for example, in FIG6 (a), the length of the heating unit 01 corresponding to the first heating segment S2 is the same as the length of the heating unit 01 corresponding to the second heating segment S1, but the widths d2 and d1 of the two are different, d2 < d1; for example, in FIG6 (b) and (c), the width of the heating unit 01 corresponding to the first heating segment S2 is the same as the width of the heating unit 01 corresponding to the second heating segment S1, but the lengths d2 and d1 of the two are different, d2 < d1. This can achieve the diversification of the heating diaphragm structure.

[0056] In some embodiments of the present disclosure, referring to FIG7 , the first heating section and the second heating section are staggered in the width direction of the heating film, thereby achieving a diversified structure of the heating film.

[0057] In some embodiments of the present disclosure, referring to (d), (e), (f), (h), (i), and (j) in FIG5 , the heating diaphragm includes a plurality of notches spaced apart along its length. This allows for a variety of heating diaphragm structures. Furthermore, in some embodiments of the present disclosure, referring to (i) in FIG5 , each notch is defined by separating a portion of the heating diaphragm from the rest and then bending it.

[0058] In some embodiments, as shown in FIG11 , the same heating film may include a plurality of different cut types, or include the same cut type with uneven density distribution.

[0059] In another aspect of the present disclosure, a method for preparing the aforementioned heating film is provided. According to an embodiment of the present disclosure, the method for preparing the heating film can be prepared by using natural graphite and graphene respectively, and the specific preparation steps are as follows:

[0060] In some embodiments, a method for preparing a heating film using natural graphite includes:

[0061] S100: providing natural graphite and performing intercalation treatment on the natural graphite to obtain expandable graphite.

[0062] In the present disclosure, natural graphite is used, which does not need to be prepared through other processes, and can further reduce the process flow of preparing the heating diaphragm and reduce costs. If artificial graphite is used, it is necessary to further set up a process flow for making artificial graphite, which will greatly increase the production cost and time of the heating diaphragm and reduce production efficiency; moreover, the use of natural flake graphite, the graphite single-layer structure is a layered structure, which can make the graphite in the prepared heating diaphragm also have a layered structure, thereby improving the centralized heating effect of the heating diaphragm. In addition, natural flake graphite has large reserves in the earth's minerals. At the same time, the carbon-based heating diaphragm material does not require high-temperature graphitization during the preparation process, and can be produced continuously, which can further improve production efficiency and reduce production costs; the lack of high-temperature graphitization also improves production safety.

[0063] In addition, natural flake graphite has large reserves in the earth's mineral resources. At the same time, the heating membrane material disclosed in the present invention does not require high-temperature graphitization during the preparation process and can be produced continuously, which can further improve production efficiency and reduce production costs; the absence of high-temperature graphitization also improves production safety.

[0064] In some embodiments, the specific method of intercalation treatment can be to intercalate natural flake graphite with oxides such as concentrated sulfuric acid and / or hydrogen peroxide to obtain expandable graphite.

[0065] S200: performing expansion treatment on the expandable graphite to obtain expanded graphite.

[0066] In some embodiments, upon entering the expansion furnace, expandable graphite experiences a transient high temperature, rapidly expanding to form graphite worms, also known as expanded graphite. This expansion process can achieve expansion multiples of 30 to 400 times. The expansion process occurs at a temperature of 850-1200°C and for a time of 0.7 to 1.3 seconds.

[0067] S300: Rolling, first heat treatment, and cutting the expanded graphite to obtain a heating film. The heating films obtained after cutting can be seen in Figures 5 to 7. The specific cutting characteristics are consistent with the requirements described above and will not be described in detail here.

[0068] There are no special requirements for the specific method of the first heat treatment, and those skilled in the art can adopt the specific heat treatment method for deoxidizing graphite oxide to obtain graphite in the prior art.

[0069] In this way, the thickness and density of the heating film can be controlled by rolling the expanded graphite. The thickness and density of the heating film are as described above and will not be described in detail here.

[0070] According to the embodiments of the present disclosure, the heating diaphragm made of graphite material obtained by using natural graphite makes the heating diaphragm have a higher heating temperature and a faster heating rate, which helps to achieve higher temperature heating and higher heating efficiency; moreover, the heating diaphragm of the present disclosure uses natural graphite, and natural graphite ore has large reserves among the earth's minerals. At the same time, the carbon-based diaphragm material does not require high-temperature graphitization during the preparation process, does not need to be prepared by other processes, and can be produced continuously to reduce costs. In general, the carbon-based diaphragm material has the advantages of a wide range of raw material sources, a simple preparation process, good product stability, and performance parameters that can be adjusted according to demand and are easy to adjust. It has huge advantages in reducing product costs, enhancing product reliability, and enriching product types. If artificial graphite is used, it is necessary to further set up a process flow for making artificial graphite, which will greatly increase the production cost and time of the heating membrane and reduce production efficiency; moreover, the heating membrane prepared with natural graphite as the material has a faster heating speed, a higher heating temperature, and a faster temperature rise rate; moreover, the heating membrane of the above density and thickness can meet the requirements of different power sizes for the heating membrane; moreover, the carbon-based heating membrane disclosed in the present invention has high manufacturability, that is, a high production yield and a long service life.

[0071] In some embodiments, a method for preparing a heating film using graphene includes:

[0072] S400: The graphene and the additive are mixed and dispersed uniformly to obtain a dispersion.

[0073] In some embodiments, the graphene used is a graphene microplatelet, the plane size of the graphene microplatelet is 1-100 μm, and the specific surface area is 30-800 m 2 / g, the graphene microsheets required above are easy to disperse evenly.

[0074] In some embodiments, the additive includes at least one of carboxymethyl cellulose, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, and water-based polyurethane. The addition of the above additives can effectively increase the film-forming property of the graphene microsheets.

[0075] Furthermore, based on the total mass of the dispersion, the mass fraction of the additive is less than or equal to 5%, such as 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc. The amount of the additive is low and will not affect the good performance of the prepared heating film.

[0076] S500: The dispersion liquid is applied to obtain a dispersion liquid film.

[0077] In some embodiments, there are no special requirements for the specific coating method. Those skilled in the art can flexibly select an appropriate coating method according to actual needs, such as spin coating, spray coating, etc.

[0078] S600: performing a second heat treatment on the dispersion film to obtain a carbon-based primary film.

[0079] In this step, the graphene is deoxidized through a second heat treatment to produce a graphite material. The heat treatment can be performed under vacuum or an inert atmosphere at a temperature of 1500-3000°C. This method can produce graphite with a high carbon content, for example, a carbon content exceeding 99%.

[0080] S700: The carbon-based primary film is rolled and cut to obtain a heating film. The heating film is cut into a certain shape. The specific cutting shape can be seen in Figures 5, 6 and 7. The characteristics of the specific cutting shape are consistent with the requirements described above and will not be described in detail here.

[0081] According to the embodiments of the present disclosure, the use of graphene as a raw material not only facilitates the production of a heating film with a high carbon content, but also allows for a simple and mature processing technique and low production costs. Furthermore, the graphene microsheets used have excellent thermal conductivity and tensile strength, thereby helping to improve the heating temperature and mechanical strength of the prepared heating film.

[0082] In another aspect of the present disclosure, a heat pipe is provided. According to an embodiment of the present disclosure, the heat pipe includes the aforementioned heating film. As a result, the heat pipe achieves a higher heating temperature, a faster heating rate, and a more concentrated heating area, significantly improving the heating efficiency of the heat pipe. Those skilled in the art will appreciate that the heat pipe possesses all the features and advantages of the aforementioned heating film, and further details will not be given here.

[0083] In some embodiments, referring to Figure 8 (the S area in the figure refers to a partial cross-sectional view of the sleeve), Figure 9 and Figure 10, the heating tube also includes a sleeve 10, and the heating membrane 20 is placed in the sleeve 10. Terminals 21 are provided at both ends of the heating membrane 20, wherein the sleeve can be a quartz glass tube or the like.

[0084] In another aspect of the present disclosure, a heating appliance is provided. According to an embodiment of the present disclosure, the heating appliance includes the aforementioned heating pipe. As a result, the heating appliance has a higher heating temperature, a faster heating rate, and a more concentrated heating area, greatly improving the heating efficiency of the heating appliance.

[0085] According to an embodiment of the present disclosure, the heating appliance is an electric oven, a microwave oven, a steam oven, an electric kettle, an electric blanket, an electric fan heater, an electric heater, a bathroom heater, an electric ceramic stove or a disinfection cabinet.

[0086] Those skilled in the art will understand that, in addition to the above-mentioned heating tubes, the heating appliance also includes the necessary structures or components of the heating appliance. Taking the electric oven as an example, in addition to the above-mentioned heating tubes, it also includes the necessary structures or components such as the shell, heating space, base, and plug.

[0087] Example

[0088] Examples 1 to 7, Comparative Examples 1 and 2

[0089] The heating film is made of natural flake graphite, and the density of the heating film is 1.8g / cm 3 , with a length of 300 mm, a width of 8 mm, and a cut shape as shown in (a) in Figure 5. The density, power, and performance tests of the heating film can be found in Table 1 below. As can be seen from Table 1, under the condition of a certain density, the power of the heating film increases with increasing thickness. However, too large or too small a thickness will affect the manufacturability of the heating film. Moreover, the heating films in the embodiments all have a relatively high heating temperature.

[0090] Table 1

[0091] Examples 8 to 14, Comparative Examples 3 and 4

[0092] The heating film is made of natural flake graphite, and the density of the heating film is 1.8g / cm 3 , with a length of 600 mm, a width of 8 mm, and a cut shape as shown in (a) in Figure 5. The density, power, and performance tests of the heating film can be found in Table 2 below. As can be seen from Table 2, under the condition of a certain density, the power of the heating film increases with increasing thickness. However, too large or too small a thickness will affect the manufacturability of the heating film. Moreover, the heating films in the embodiments all have a relatively high heating temperature.

[0093] Table 2

[0094] Examples 15 to 21, Comparative Examples 5 and 6

[0095] The heating film is made of natural flake graphite, and the density of the heating film is 0.6g / cm 3 , with a length of 300 mm, a width of 8 mm, and a cut shape as shown in (a) in Figure 5. The density, power, and performance tests of the heating film can be found in Table 3 below. As can be seen from Table 3, under the condition of a certain density, the power of the heating film increases with increasing thickness. However, too large or too small a thickness will affect the manufacturability of the heating film. Moreover, the heating films in the embodiments all have a relatively high heating temperature.

[0096] Table 3

[0097] Examples 22 to 28, Comparative Examples 7 and 8

[0098] The heating film is made of natural flake graphite, and the density of the heating film is 0.6g / cm 3 , with a length of 600 mm, a width of 8 mm, and a cut shape as shown in (a) in Figure 5. The density, power, and performance tests of the heating film can be found in Table 4 below. As can be seen from Table 4, under the condition of a certain density, the power of the heating film increases with increasing thickness. However, too large or too small a thickness will affect the manufacturability of the heating film. Moreover, the heating films in the embodiments all have a relatively high heating temperature.

[0099] Table 4

[0100] Examples 29 to 35, Comparative Examples 9 and 10

[0101] The heating film is made of natural flake graphite, and the density of the heating film is 1.0g / cm 3 , with a length of 600 mm, a width of 8 mm, and a cut shape as shown in (a) in Figure 5. The density, power, and performance tests of the heating film can be found in Table 5 below. As can be seen from Table 5, under the condition of a certain density, the power of the heating film increases with increasing thickness. However, too large or too small a thickness will affect the manufacturability of the heating film. Moreover, the heating films in the embodiments all have a relatively high heating temperature.

[0102] Table 5

[0103] Examples 36 to 42, Comparative Examples 11 and 12

[0104] The heating film is made of natural flake graphite, and the density of the heating film is 1.5g / cm 3 , with a length of 600 mm, a width of 8 mm, and a cut shape as shown in (a) in Figure 5. The density, power, and performance tests of the heating film can be found in Table 6 below. As can be seen from Table 6, under the condition of a certain density, the power of the heating film increases with increasing thickness. However, too large or too small a thickness will affect the manufacturability of the heating film. Moreover, the heating films in the embodiments all have a relatively high heating temperature.

[0105] Table 6

[0106] From the test data in Tables 1 to 6 above, it can be seen that the heating film of the present disclosure meets the requirements of thickness of 0.04 mm to 2 mm and density of 0.6 g / cm 3 ~1.8g / cm 3 It can be used to make various ultra-low power or ultra-high power heating films, and obtain different heating temperatures to meet various application requirements in the market. Moreover, under certain conditions, as the thickness of the heating film increases, its heating temperature gradually decreases.

[0107] Among them, the above-mentioned method for judging manufacturability is: the heating diaphragm has good flexibility and certain rigidity, is easy to demold and transport, has good processing and manufacturing effect, is not easy to be pulled or broken, and the normal production and manufacturing pass rate is not less than 99%, which is "good", otherwise it is "poor".

[0108] The test method for the above life is: apply 1.1 times the rated voltage to the heating diaphragm, and after the continuous working time reaches 525 hours, it should meet the following requirements: (1) the heating tube has no cracks, gaps, or deformation; (2) the heating diaphragm has no breakage, no bending or deformation, and the power deviation meets the design requirements of the drawing; (3) insulation resistance: use a DC500V insulation resistance meter to test between the live parts (terminals) and the non-live parts (tube wall) of the heating tube, and the test resistance is ≥500MΩ (DC500V); (4) insulation strength: apply a voltage of 1800VAC / 3S / 5mA between the live parts (terminals) and the non-live parts (tube wall) of the heating tube, and if there is no flashover or breakdown, it is qualified.

[0109] Example 43

[0110] The thickness of the present invention is 1.0 mm and the density is 1.2 g / cm 3A heating film (cut as shown in (a) in Figure 5) was fabricated into a heating tube. This heating tube, a halogen tube, a quartz tube, and a metal tube were placed in the same oven. All heating tubes were tested at a power of 600W. The time required for each heating tube to reach 200°C was measured. The test results can be found in Table 7. Heating tubes made from heating films of different thicknesses and densities were also tested at a power of 600W. The time required for the oven to reach 200°C was measured. The test results can be found in Table 8.

[0111] Table 7

[0112] Table 8

[0113] It can be seen that the heating tube made of the heating film of the present disclosure can reach the desired heating temperature in a shorter time, that is, the heating film of the present disclosure has a faster heating rate and thus has good heating efficiency.

[0114] Examples 44 to 45, Comparative Examples 13 and 14

[0115] The heating film is made of natural flake graphite. The thickness of the heating film is 1.0mm and the density is 1.2g / cm 3 , with a width of 8 mm and a cut shape as (a) in FIG5 . The thermal diffusivity and performance tests of the heating films in different embodiments can be found in Table 9 below. The heating films of various embodiments are made into heating tubes. The power of all the heating tubes tested is 600 W. The time required for each heating tube to reach 200° C. is tested. The test results can be found in Table 9.

[0116] Table 9

[0117] The above test results show that the thermal diffusion number of the heating film of the present invention is 50m 2 / s~450m 2 / s, the life of the heating film can be effectively improved. Moreover, the heating efficiency of the heating film is high and a higher heating temperature can be reached in a shorter time. The thermal diffusion coefficient is greater than 450m 2 / s, the heating time is extended, and the density of the heating film is higher, which is more difficult to achieve in terms of technology, that is, the difficulty of the process is increased.

[0118] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0119] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and features of different embodiments or examples, unless they are mutually inconsistent.

[0120] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A heating film, wherein, The raw materials of the heating film sheet include natural graphite and / or graphene, and the heating film sheet satisfies at least one of the following conditions: The thickness of the heating film sheet is 0.04 mm to 2 mm; The density of the heating film is 0.6 g / cm 3 ~1.8 g / cm 3 .

2. The heating film according to claim 1, wherein, The carbon content of the heating film sheet is greater than or equal to 99%; 3. The heating film according to claim 1 or 2, wherein, The power of the heating film sheet is 15 W to 10,000 W; 4. The heating film according to claim 3, wherein, The heating film sheet satisfies one of the following conditions: The length of the heating film is 250 mm to 450 mm, the width is 6 mm to 10 mm, and the density of the heating film is 1.2 g / cm 3 to 1.8 g / cm 3 , and the power of the heating film is 30 W to 5000 W; The length of the heating film is 450 mm to 650 mm, the width is 6 mm to 10 mm, and the density of the heating film is 1.2 g / cm 3 ~1.8 g / cm 3 , and the power of the heating film is 25 W to 10,000 W; The length of the heating film is 250 mm to 450 mm, the width is 6 mm to 10 mm, and the density of the heating film is 0.6 g / cm 3 ~1.2 g / cm 3 , and the power of the heating film is 10 W to 3400 W; The length of the heating film is 450 mm to 650 mm, the width is 6 mm to 10 mm, and the density of the heating film is 0.6 g / cm 3 ~1.2 g / cm 3 , and the power of the heating film is 10 W to 7000 W.

5. The heating film according to any one of claims 1 to 4, wherein, The heating film sheet has a sheet structure, the natural graphite and the graphene have a sheet structure, and the sheet extension plane of the heating film sheet is substantially the same as the sheet extension plane of the natural graphite and / or the graphene; 6. The heating film according to any one of claims 1 to 5, wherein, The heating temperature of the heating film sheet is 500 °C to 1700 °C; 7. The heating film according to any one of claims 1 to 6, wherein, The material of the heating film sheet is graphite; 8. The heating diaphragm according to any one of claims 1 to 7, wherein, The heating film sheet includes a plurality of heating units arranged in sequence along the length direction, and adjacent heating units are spaced apart and connected by a connecting section; 9. The heating film according to claim 8, wherein, Each of the heating units is provided with a hollow hole; 10. The heating diaphragm according to claim 8 or 9, wherein, The heating film sheet includes a first heating section and a second heating section adjacent in the length direction, the first heating section includes a plurality of connected heating units, the second heating section includes a plurality of adjacent heating units, and the size of the heating units corresponding to the first heating section is smaller than the size of the heating units corresponding to the second heating section; and / or The first heating section and the second heating section are arranged in a staggered manner in the width direction of the heating film sheet; 11. The heating film according to any one of claims 8 to 10, wherein, The heating film sheet includes a plurality of notches spaced apart along the length direction; 12. The heating film according to claim 11, wherein, Each of the notches is defined by bending a part of the heating film sheet after separating it from the rest; 13. A method for preparing the heating diaphragm according to any one of claims 1 to 12, wherein, Comprising: Providing natural graphite and subjecting it to intercalation treatment to obtain expandable graphite; Performing an expansion treatment on the expandable graphite to obtain expanded graphite; Performing calendering, first heat treatment, and cutting on the expanded graphite to obtain the heating film sheet, Alternatively, comprising: Mixing and uniformly dispersing the graphene and an additive to obtain a dispersion; Coating the dispersion to obtain a dispersion film; Performing a second heat treatment on the dispersion film to obtain a carbon-based primary film; Performing calendering and cutting on the carbon-based primary film to obtain the heating film sheet.

14. The method according to claim 13, wherein, The conditions of the intercalation treatment are: intercalating the natural graphite with concentrated sulfuric acid and / or hydrogen peroxide to obtain the expandable graphite; The conditions of the expansion treatment are: putting the expandable graphite into an expansion furnace and expanding it at a temperature of 850 - 1200 °C to obtain the expanded graphite; 15. A heating tube, wherein, Comprising the heating film sheet according to any one of claims 1 to 12; 16. A heating appliance, wherein, Comprising the heating tube according to claim 15; 17. The heating appliance according to claim 16, wherein, The heating electrical appliance is an electric oven, a microwave oven, a steam oven, an electric kettle, an electric blanket, an electric warm air blower, an electric heater, a bathroom heater, an electric ceramic stove, or a disinfection cabinet.

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