Graphene radiant panel structure and graphene warmer

Abstract

The graphene radiant panel structure comprises a base layer substrate, a conductive silver layer, a graphene heating layer and an insulating layer, a first silver coating and a second silver coating of the conductive silver layer are respectively and correspondingly provided with a power connection end part and a heating main body part except the power connection end part, the first silver coating and the second silver coating are symmetrically arranged on the surface of the base layer substrate; the graphene heating layer is arranged on the surfaces of the base layer substrate, the first silver coating and the second silver coating; the insulating layer is arranged on the surfaces of the base layer substrate and the graphene heating layer. In this way, it is ensured that the graphene heating layer and the base layer substrate are sintered, welded and formed, the structural stability and sintering uniformity of all the layers are ensured, and the interlayer bonding strength is improved; the current distribution is optimized by symmetrical silver sheet layout, the heating surface uniformity effect is achieved, and the electrothermal conversion efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of heating plate technology, and in particular to a graphene radiant plate structure and a graphene heater. Background Technology

[0002] A graphene radiant panel is a heating or radiating device made using the excellent thermal and electrical properties of graphene. It typically consists of a graphene heating layer, a heat insulation layer, and a metal shell. Due to its high efficiency, safety, and health benefits, graphene radiant panels are widely used in industrial heating, medical therapy, and building heating. For example, Chinese invention patent application CN112804773A, entitled "A heating panel and its preparation method," describes a process involving an insulating substrate, a conductive paste (preferably graphene) coated on the surface of the substrate, and sintering to form a conductive layer. Electrode paste (preferably conductive silver paste) is then coated on both sides of the conductive layer, and sintered to form an electrode layer. The non-electrode areas of the conductive layer are then laser-etched to form an etched conductive layer. Finally, the material obtained from the above steps is encapsulated and sintered to obtain the heating panel.

[0003] However, the existing technology still has the following drawbacks:

[0004] 1. In the existing layered structure design of graphene heating plates, the graphene, which serves as the conductive layer, is usually sintered with the insulating substrate first, and then conductive silver paste, insulating packaging layer, etc. are sintered in sequence. Since the sintering temperature of graphene is lower than that of conductive silver paste, when sintering graphene first and then sintering conductive silver paste, the already sintered graphene will face the problem of being reheated and melted, which will ultimately affect the entire sintering process, sintering quality and heat conversion effect.

[0005] 2. When sintering graphene and conductive silver paste, the conductive silver paste is usually covered on both sides of the graphene surface. This results in a small thermal contact area between the conductive silver paste and graphene, which affects the thermal conversion efficiency.

[0006] 3. After packaging and sintering, the electrode layer formed by the sintering of conductive silver paste did not form conductive silver terminals exposed outside the packaging layer, which caused inconvenience in wiring in subsequent applications. Utility Model Content

[0007] In order to overcome the shortcomings of the existing technology, one of the objectives of this utility model is to provide a graphene radiation plate structure.

[0008] One of the objectives of this utility model is achieved through the following technical solution: a graphene radiant plate structure, comprising a base substrate, a conductive silver layer, a graphene heating layer, and an insulating layer. The conductive silver layer has a first silver coating and a second silver coating, with the first and second silver coatings respectively having an electrical connection end and a heating body other than the electrical connection end. The first and second silver coatings are symmetrically arranged on the surface of the base substrate. The graphene heating layer is arranged on the surface of the base substrate, the first silver coating, and the second silver coating. The insulating layer is arranged on the surface of the base substrate and the graphene heating layer. A first sintering, a second sintering, and a third sintering are performed according to the arrangement of the conductive silver layer, the graphene heating layer, and the insulating layer, with the sintering temperatures of the first sintering, the second sintering, and the third sintering set in descending order.

[0009] Furthermore, the graphene heating layer covers the surface of the heating body and covers more than 90% of the surface area of ​​the heating body.

[0010] Furthermore, the insulating layer completely covers the surface of the graphene heating layer and the heating body, and the electrical terminals of the first silver coating and the second silver coating are exposed outside the insulating layer.

[0011] Furthermore, one end of the heating body of the first silver coating and the second silver coating is bent at 90° to each other and then bent at 90° in the same direction to form the power connection end that is connected to the external circuit.

[0012] Furthermore, the conductive silver layer, graphene heating layer, and insulating layer are sintered and solidified sequentially on the base substrate in descending order of sintering temperature.

[0013] Furthermore, the graphene heating layer has a first heating layer and a second heating layer, the first heating layer is sintered and connected to the conductive silver layer, the second heating layer is sintered and connected to the insulating layer, and the density of the first heating layer is greater than that of the second heating layer.

[0014] Furthermore, the base material is one of mica board, microcrystalline glass board, ceramic board, magnesium aluminum compound board, and quartz board, and the conductive silver layer is conductive silver paste. The conductive silver paste is applied along a set conductive path and then sintered together for the first time.

[0015] Furthermore, the graphene heating layer is a graphene slurry, and the graphene slurry is coated along the surface of the base substrate and the conductive silver layer and then sintered together.

[0016] Furthermore, the insulating layer is a ceramic coating, and the ceramic coating is applied along the surface of the base substrate, the conductive silver layer, and the graphene heating layer, and then sintered together three times.

[0017] In order to overcome the shortcomings of the existing technology, the second objective of this utility model is to provide a graphene heater.

[0018] The second objective of this utility model is achieved by the following technical solution: a graphene heater, comprising a heater shell and the graphene radiant plate structure.

[0019] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0020] (1) The graphene radiant plate structure provided in this application arrangement arranges the base material, conductive silver layer, graphene heating layer and insulating layer in a layered structure. First, the conductive silver layer with a higher sintering temperature is sintered, and then the graphene heating layer with a lower sintering temperature is sintered. The first sintering forms a stable conductive skeleton. During the second sintering, the graphene layer is not affected by the high temperature, avoiding the graphene from melting at a high temperature. This ensures that the graphene heating layer and the base material are sintered and fused together, ensuring the stability of each layer structure, the uniformity of sintering, and improving the interlayer bonding strength. The symmetrical silver sheet layout optimizes the current distribution, achieving a uniform heating surface and improving the electrothermal conversion efficiency.

[0021] (2) By optimizing the sintering design of the entire heating body of the first and second silver coatings by covering the graphene heating layer, the contact area between the graphene heating layer and the conductive silver layer is increased, and the interfacial thermal resistance is reduced, so that the interfacial thermal resistance between the conductive silver layer and the graphene heating layer is reduced to 0.15 K·cm. 2 / W, which improves thermal conversion efficiency by 15%-20% compared to traditional structures.

[0022] (3) By setting the electrical connection end on the conductive silver layer and reserving an uncovered area at the edge of the graphene heating layer and insulating layer during coating and sintering, the exposed electrical connection end is formed after sintering. The exposed design of the electrical connection end makes the contact resistance ≤0.05Ω, eliminating the need for subsequent drilling or cutting processes, simplifying the wiring steps, shortening the wiring operation time by 60%, avoiding the risk of short circuit caused by insulation layer damage, and reducing installation costs. Attached Figure Description

[0023] Figure 1 This is a three-dimensional schematic diagram of the graphene radiating plate structure in the first embodiment of this utility model;

[0024] Figure 2 This is a partial cross-sectional view of the graphene radiating plate structure in the first embodiment of this utility model.

[0025] Figure 3 for Figure 2 A magnified view of a portion of point A in the middle;

[0026] Figure 4This is a schematic diagram showing the layered structural connection relationship between the silver wire layer, the heating layer, and the insulating layer of the graphene radiant plate structure in the first embodiment of this utility model.

[0027] Figure 5 This is a schematic diagram showing the layered structural connection relationship between the silver wire layer and the heating layer in the graphene radiant plate structure of the first embodiment of this utility model.

[0028] Figure 6 This is a schematic diagram of the silver wire layer of the graphene radiating plate structure in the first embodiment of this utility model;

[0029] Figure 7 This is a partial cross-sectional view of the graphene heater in the second embodiment of this utility model.

[0030] In the picture:

[0031] 10. Base material;

[0032] 20. Conductive silver layer; 201. First silver coating; 202. Second silver coating; 203. Electrically connected end; 204. Heating body;

[0033] 30. Graphene heating layer; 301. First heating layer; 302. Second heating layer;

[0034] 40. Insulation layer. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0036] First Embodiment

[0037] like Figure 1-6 As shown, a graphene radiant panel structure is widely used in industrial heating, medical physiotherapy, building heating and other fields. The graphene radiant panel structure includes a base substrate 10, a conductive silver layer 20, a graphene heating layer 30 and an insulating layer 40. Among them, microcrystalline glass is preferably selected as the base substrate 10, for example, a 0.8mm thick microcrystalline glass. In addition, the base substrate 10 can also be selected from mica board, ceramic board, magnesium aluminum compound board and quartz board.

[0038] Conductive silver paste is applied to the substrate 10 according to a preset conductive heating path to form a first silver coating 201 and a second silver coating 202 arranged symmetrically. The first silver coating 201 and the second silver coating 202 are respectively provided with a power receiving end 203 and a heating body part 204 other than the power receiving end 203. Moreover, the power receiving end 203 and the heating body part 204 of each silver sheet are integrally bent. The conductive silver paste is first sintered on the substrate 10 at 600°C (the sintering temperature is for reference only and can be adjusted according to the actual application) so that the silver sheet is solidified with the substrate 10 to form a conductive silver layer 20.

[0039] Subsequently, a graphene slurry is coated onto the surfaces of the conductive silver layer 20 and the base substrate 10. For example, the graphene slurry contains 15 wt% graphene nanosheets (≤5 layers) and 3 wt% silane coupling agent. In this embodiment, a single layer of graphene slurry containing 20% ​​nano-graphene sheets is preferred, with a coating thickness of 50 μm. Furthermore, the graphene slurry covers the entire heating body 204 of the first silver coating 201 and the second silver coating 202, specifically by spraying or screen printing the graphene slurry onto the surface of the heating body 204 of the silver sheet, with a coverage area ≥90%, leaving an uncovered area at the edge for the electrical connection end 203. A secondary sintering is performed at 500°C (sintering temperature is for reference only and can be adjusted according to actual application) to solidify the graphene slurry with the conductive silver layer 20 and the base substrate 10 to form the graphene heating layer 30.

[0040] Therefore, by optimizing the sintering design of the graphene heating layer 30, the contact area between the graphene heating layer 30 and the conductive silver layer 20 is increased, and the interfacial thermal resistance is reduced, thereby lowering the interfacial thermal resistance between the conductive silver layer 20 and the graphene heating layer 30 to 0.15 K·cm. 2 / W, which improves thermal conversion efficiency by 15%-20% compared to traditional structures.

[0041] Finally, a ceramic coating is applied to the surface of the base substrate 10 and the graphene heating layer 30. For example, the ceramic coating is prepared by the sol-gel method with an Al2O3 content of 70%. After coating, air bubbles are eliminated by roller pressing, and the thickness is 100μm. Three sintering processes are carried out at 400℃ (the sintering temperature is for reference only and can be adjusted according to the actual application) to solidify the ceramic coating with the base substrate 10 and the graphene heating layer 30 to form an insulating layer 40. According to the above sintering and curing design, the conductive silver layer, the graphene heating layer, and the insulating layer are sintered and cured sequentially on the base substrate in descending order of sintering temperature.

[0042] Similarly, during the coating and sintering of ceramic coatings, a mask is used to cover the electrical terminals 203 when the insulating layer 40 is coated. After sintering, exposed conductive silver terminals are formed, which means it is necessary to ensure that the electrical terminals 203 are exposed. Therefore, directly exposing the electrical terminals 203 (electrode terminals) of the silver sheet, the exposed design of the electrical terminals 203 ensures a contact resistance of ≤0.05Ω, eliminates the need for subsequent drilling or cutting processes, simplifies wiring steps, reduces wiring operation time by 60%, avoids the risk of short circuits caused by damage to the insulating layer 40, and reduces installation costs.

[0043] In summary, through the layered structure arrangement of the base substrate 10, conductive silver layer 20, graphene heating layer 30, and insulating layer 40, the conductive silver layer with a higher sintering temperature is sintered first, followed by the graphene heating layer with a lower sintering temperature. Furthermore, the descending temperature gradient sintering optimization (600℃→500℃→400℃) ensures that the first sintering forms a stable conductive framework. During the second sintering, the graphene layer is unaffected by the high temperature, preventing secondary melting of the graphene. This ensures the graphene heating layer and the base substrate are sintered and fused together, guaranteeing the structural stability and sintering uniformity of each layer, and improving the interlayer bonding strength. Additionally, the symmetrical silver sheet layout optimizes the current distribution, achieving a uniform heating surface and improving the electrothermal conversion efficiency.

[0044] Regarding the bending process of the silver sheet, when using a stamping die to bend the conductive silver layer 20 twice, firstly, the ends of the heating body 204 of the first silver coating 201 and the second silver coating 202 are bent at 90° in opposite directions to form an L-shaped structure, and then bent at 90° in the same direction to form a horizontal electrical terminal. The bending radius is controlled within 0.3mm to avoid cracking of the silver layer.

[0045] Thus, by bending the first silver coating 201 and the second silver coating 202, the exposed design of the conductive silver layer 20's electrical connection end 203 can be better guaranteed during the layered coating process of the graphene radiating plate, avoiding accidental coating coverage; in addition, the double bending structure of the silver sheet enables the electrode tensile strength to reach 85MPa, and the uniformity of current density distribution at the bending point is improved by 40%, avoiding local overheating.

[0046] Second Embodiment

[0047] like Figure 7 As shown, the difference between this embodiment and the first embodiment is that two layers of graphene slurry are coated on the surface of the base substrate 10 and the conductive silver layer 20; that is, the graphene slurry is coated in two stages. The first layer is formed by high-pressure spraying to form a dense first heating layer 301 (containing 30% graphene). The first heating layer 301 is first coated on the surface of the base substrate 10 and the conductive silver layer 20.

[0048] Then, a second heating layer 302 is coated on the first heating layer 301. The second layer is formed by impregnation to form a multi-gradient density structure to form a directional heat conduction channel (containing 15% graphene), and is sintered with the insulating layer 40. The in-plane thermal conductivity reaches 650 W / (m·K), and the normal thermal conductivity is controlled at 2.3 W / (m·K), so as to achieve in-plane temperature uniformity.

[0049] Therefore, by designing a double-layer coating with different densities for the graphene heating layer 30, the high-density layer ensures the conductivity of the interface, while the low-density layer reduces the stress on the insulating layer 40, resulting in a matching overall thermal expansion coefficient and extending the service life.

[0050] Third Embodiment

[0051] This application provides a graphene heater in which the graphene radiant plate is embedded in a metal heater shell, and the electrical terminal 203 is connected to the power cord by screws. If necessary, a silicone thermal pad is filled between the radiant plate and the shell to form a 2mm air gap insulation layer, and the overall thickness is controlled within 15mm.

[0052] This results in a thermal response time of ≤30 seconds, a radiation efficiency of 92%, energy savings of 37% compared to traditional metal heating elements, and a surface temperature unevenness of ≤3℃, meeting the demand for rapid heating.

[0053] The above embodiments are merely preferred embodiments of this utility model and should not be construed as limiting the scope of protection of this utility model. Any non-substantial changes and substitutions made by those skilled in the art based on this utility model shall fall within the scope of protection claimed by this utility model.

Claims

1. A graphene radiating plate structure, characterized in that, The device includes a base substrate, a conductive silver layer, a graphene heating layer, and an insulating layer. The conductive silver layer has a first silver coating and a second silver coating. The first silver coating and the second silver coating are respectively provided with a power receiving end and a heating body other than the power receiving end. The first silver coating and the second silver coating are symmetrically arranged on the surface of the base substrate. The graphene heating layer is arranged on the surface of the base substrate, the first silver coating, and the second silver coating. The insulating layer is arranged on the surface of the base substrate and the graphene heating layer.

2. The graphene radiating plate structure as described in claim 1, characterized in that, The graphene heating layer covers the surface of the heating body and covers more than 90% of the surface area of ​​the heating body.

3. The graphene radiating plate structure as described in claim 1, characterized in that, The insulating layer completely covers the surface of the graphene heating layer and the heating body, and the electrical terminals of the first silver coating and the second silver coating are exposed outside the insulating layer.

4. The graphene radiating plate structure as described in claim 3, characterized in that, After one end of the heating body of the first silver coating and the second silver coating is bent at 90° opposite to each other, it is then bent at 90° in the same direction to form the power connection end that is connected to the external circuit.

5. The graphene radiating plate structure according to any one of claims 1-4, characterized in that, The conductive silver layer, graphene heating layer, and insulating layer are sintered and solidified sequentially on the base substrate in descending order of sintering temperature.

6. The graphene radiating plate structure according to any one of claims 1-4, characterized in that, The graphene heating layer has a first heating layer and a second heating layer. The first heating layer is sintered and connected to the conductive silver layer, and the second heating layer is sintered and connected to the insulating layer. The density of the first heating layer is greater than that of the second heating layer.

7. The graphene radiating plate structure as described in claim 1, characterized in that, The base material is one of mica board, microcrystalline glass board, ceramic board, magnesium aluminum compound board, and quartz board. The conductive silver layer is conductive silver paste, and the conductive silver paste is applied along a set conductive path and then sintered together for the first time.

8. The graphene radiating plate structure as described in claim 7, characterized in that, The graphene heating layer is a graphene slurry, and the graphene slurry is coated along the surface of the base substrate and the conductive silver layer and then sintered together.

9. The graphene radiating plate structure as described in claim 8, characterized in that, The insulating layer is a ceramic coating, and the ceramic coating is applied along the surface of the base substrate, the conductive silver layer, and the graphene heating layer, and then sintered together three times.

10. A graphene heater, characterized in that, It includes a heater housing and a graphene radiant panel structure as described in any one of claims 1-9.

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