CN101636006B - Plane heat source - Google Patents

Abstract

A surface heat source, including a heating layer; and, at least two electrodes, the at least two electrodes are arranged at intervals, and are respectively electrically connected to the heating layer; wherein, among the at least two electrodes, at least one electrode includes a carbon nanotube structure.

Description

surface heat source

technical field

The invention relates to a surface heat source, in particular to a surface heat source based on carbon nanotubes.

Background technique

Heat sources play an important role in people's production, life and scientific research. The surface heat source is a kind of heat source, and its characteristic is that the surface heat source has a plane structure, and the object to be heated is placed above the plane structure to heat the object. Therefore, the surface heat source can heat all parts of the object to be heated at the same time, and the heating surface Wide, uniform heating and high efficiency. Surface heat sources have been successfully used in industrial fields, scientific research fields, or living fields, such as electric heaters, infrared therapeutic devices, electric heaters, etc.

The existing surface heat source generally includes a heating layer and at least two electrodes, and the at least two electrodes are arranged on the surface of the heating layer and electrically connected with the surface of the heating layer. When the electrodes connected to the heating layer are passed through a low-voltage current, heat is released from the heating layer immediately. The electrodes of existing surface heat sources usually use a metal sheet, metal wire, metal film, indium tin oxide (ITO) layer, antimony tin oxide (ATO) layer, conductive silver glue layer or conductive polymer layer, etc. However, electrodes using metal sheets, metal wires, metal films, indium tin oxide (ITO) layers, antimony tin oxide (ATO) layers, conductive silver glue layers or conductive polymer layers as surface heat sources have the following disadvantages: first , the resistivity of the electrode is large, so the loss of electric energy is also large. Second, the electrode has poor flexibility and mechanical strength, is easy to break after long-term folding, and has a short service life, so it is not easy to be applied to a flexible surface heat source. Third, the density of the electrode is high, the weight is heavy, and it is inconvenient to use.

In view of this, it is indeed necessary to provide a surface heat source, and the electrode resistivity of the surface heat source is small, the flexibility and mechanical strength are high, the long-term folding is not easy to break, and the density is small, and the weight is light.

Contents of the invention

A surface heat source, including a heating layer; and, at least two electrodes, the at least two electrodes are arranged at intervals, and are respectively electrically connected to the heating layer; wherein, among the at least two electrodes, at least one electrode includes a carbon nanotube structure.

Compared with the prior art, the surface heat source has the following advantages: First, the carbon nanotube has excellent electrical conductivity, so the resistance of the electrode is small, which is beneficial to reduce power consumption and improve heating efficiency. Second, the excellent mechanical properties of carbon nanotubes make the carbon nanotube structure have good flexibility and mechanical strength. Therefore, using the carbon nanotube structure as an electrode can correspondingly improve the durability of the surface heat source, especially the flexible surface heat source. The surface heat source has a long service life; thirdly, the density of carbon nanotubes is small, so the surface heat source is light in weight and easy to use.

Description of drawings

Fig. 1 is a schematic structural diagram of a surface heat source in an embodiment of the technical solution.

Fig. 2 is a schematic cross-sectional view along line II-II of Fig. 1 .

Fig. 3 is a scanning electron micrograph of the carbon nanotube thin film of the embodiment of the technical solution.

Fig. 4 is a scanning electron micrograph of long carbon nanotubes with bundle structure according to the embodiment of the technical solution.

Fig. 5 is a scanning electron micrograph of a carbon nanotube long wire with a stranded wire structure according to an embodiment of the technical solution.

Detailed ways

The surface heat source provided by the technical solution will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Please refer to Fig. 1 and Fig. 2, the embodiment of this technical solution provides a surface heat source 10, the surface heat source 10 includes a base 18, a reflective layer 17, a heating layer 16, a first electrode 12, a second electrode 14 and an insulating protective layer 15. The reflective layer 17 is disposed on the surface of the substrate 18 . The heating layer 16 is disposed on the surface of the reflective layer 17 . The first electrode 12 and the second electrode 14 are spaced apart from each other on the surface of the heating layer 16 , and are in electrical contact with the heating layer 16 , so as to allow current to flow through the heating layer 16 . The insulating protection layer 15 is disposed on the surface of the heating layer 16 and covers the first electrode 12 and the second electrode 14 to prevent the heating layer 16 from absorbing external impurities.

The shape of the base 18 is not limited, and it has a surface for supporting the heating layer 16 or the reflective layer 17 . Preferably, the base 18 is a plate-shaped base, and its material can be rigid materials such as ceramics, glass, resin, quartz, etc., or flexible materials such as plastics or flexible fibers. When it is a flexible material, the surface heat source 10 can be bent into any shape according to needs during use. Wherein, the size of the base 18 is not limited, and can be changed according to actual needs. The preferred substrate 18 of this embodiment is a ceramic substrate. In addition, when the heating layer 16 has a certain self-supporting property and stability, the base 18 in the surface heat source 10 is an optional structure.

The reflective layer 17 is provided to reflect the heat generated by the heating layer 16, thereby controlling the direction of heating, for single-sided heating, and further improving the heating efficiency. The reflective layer 17 is made of a white insulating material, such as metal oxide, metal salt or ceramics. In this embodiment, the reflective layer 17 is an aluminum oxide layer with a thickness of 100 microns to 0.5 mm. The reflective layer 17 can be formed on the surface of the substrate 18 by sputtering or other methods. It can be understood that the reflective layer 17 can also be arranged on the surface of the substrate 18 away from the heating layer 16, that is, the substrate 18 is arranged between the heating layer 16 and the reflective layer 17, so as to further enhance the ability of the reflective layer 17 to reflect heat. effect. When the surface heat source 10 does not include the base 18 , the heating layer 16 can be directly disposed on the surface of the reflective layer 17 . The reflective layer 17 is an optional structure. The heating layer 16 can be directly disposed on the surface of the substrate 18 , at this time, the heating direction of the surface heat source 10 is not limited, and can be used for double-sided heating.

The material of the heating layer 16 is not limited, it may be a wire layer, an electrothermal film, a carbon fiber layer or a carbon nanotube layer. When a carbon nanotube layer is used as the heating layer 16, the carbon nanotube layer includes a plurality of uniformly distributed carbon nanotubes. The carbon nanotubes in the carbon nanotube layer are ordered or disordered. The carbon nanotube layer has a thickness of 0.01 micron to 2 mm. The carbon nanotubes in the carbon nanotube layer include one or more of single-wall carbon nanotubes, double-wall carbon nanotubes and multi-wall carbon nanotubes. The single-walled carbon nanotubes have a diameter of 0.5 nm to 10 nm, the double-walled carbon nanotubes have a diameter of 1.0 nm to 15 nm, and the multi-walled carbon nanotubes have a diameter of 1.5 nm to 50 nm. The length of the carbon nanotubes is greater than 50 microns, preferably 200-900 microns. When the surface heat source 10 includes a substrate 18, the carbon nanotube layer can be fixed on the surface of the substrate 18 by an adhesive or intermolecular force. Carbon nanotubes have good electrical conductivity and thermal stability, as an ideal black body structure, and have relatively high heat radiation efficiency.

The first electrode 12 and the second electrode 14 are respectively electrically connected to the heating layer 16 , can be arranged on the same surface of the heating layer 16 or can be arranged on different surfaces of the heating layer 16 , and are electrically connected to the heating layer 16 . The first electrode 12 and the second electrode 14 can be disposed on the surface of the heating layer 16 through an adhesive or conductive adhesive (not shown) of the carbon nanotube layer. The conductive adhesive can better fix the first electrode 12 and the second electrode 14 on the surface of the carbon nanotube layer while realizing the electrical contact between the first electrode 12 and the second electrode 14 and the carbon nanotube layer. A voltage can be applied to the heating layer 16 via the first electrode 12 and the second electrode 14 . Wherein, the first electrode 12 and the second electrode 14 are spaced apart, so that when the heating layer 16 using the carbon nanotube layer is energized and heats up, a certain resistance value is connected to avoid short circuit phenomenon. Preferably, the first electrode 12 and the second electrode 14 are disposed on the surface of the heating layer 16 and located at both ends of the heating layer 16 .

At least one of the first electrode 12 and the second electrode 14 includes a carbon nanotube structure. The carbon nanotube structure is fixed on the surface of the heating layer 16 through a conductive adhesive or intermolecular force, and is electrically connected to the heating layer 16 . The carbon nanotubes in the carbon nanotube structure include one or more of single-wall carbon nanotubes, double-wall carbon nanotubes and multi-wall carbon nanotubes. In this embodiment, metallic carbon nanotubes are preferred. The single-walled carbon nanotubes have a diameter of 0.5 nm to 10 nm, the double-walled carbon nanotubes have a diameter of 1.0 nm to 15 nm, and the multi-walled carbon nanotubes have a diameter of 1.5 nm to 50 nm. The length of the carbon nanotubes is greater than 50 microns.

Specifically, the carbon nanotube structure includes an ordered carbon nanotube film or at least two layers of ordered carbon nanotube films overlapping and intersecting, or at least one carbon nanotube long line.

When the carbon nanotube structure includes at least one ordered carbon nanotube film. Please refer to FIG. 3 , the ordered carbon nanotube film can be obtained by directly stretching a carbon nanotube array. The ordered carbon nanotube film includes a plurality of carbon nanotubes aligned along the stretching direction. The carbon nanotubes are uniformly distributed and parallel to the surface of the carbon nanotube film. Specifically, the ordered carbon nanotube film includes a plurality of carbon nanotubes 163 connected end-to-end and arranged in a preferred orientation along the same direction. The plurality of carbon nanotubes 163 are connected by Van der Waals force. On the one hand, the carbon nanotubes 163 connected end to end are connected by Van der Waals force. On the other hand, the carbon nanotubes 163 with preferred orientation are connected by Van der Waals force. , the ordered carbon nanotube film has good flexibility, can be bent and folded into any shape without breaking, and the electrode using the ordered carbon nanotube film has a long service life.

The ordered carbon nanotube film is obtained by further processing the carbon nanotube array, so its length is not limited, and its width is related to the size of the substrate on which the carbon nanotube array grows, and can be produced according to actual needs. In this embodiment, a super-aligned carbon nanotube array is grown on a 4-inch substrate by vapor deposition. The ordered carbon nanotube film may have a width of 0.01 cm to 10 cm and a thickness of 0.01 micron to 100 micron. The thickness of the ordered carbon nanotube film is preferably 0.1 micron to 10 micron.

In addition, the ordered carbon nanotube film may also include a plurality of long carbon nanotubes arranged in parallel. The long carbon nanotube has a length of 1 cm to 5 cm and a diameter of 0.5 nm to 50 nm. Since the long carbon nanotube is a single carbon nanotube, its resistance is smaller. Therefore, using the ordered carbon nanotube film as an electrode can conduct current more effectively and reduce the loss of electric energy.

When the carbon nanotube structure includes at least two stacked ordered carbon nanotube films, the adjacent ordered carbon nanotube films are closely combined by van der Waals force. Further, the number of layers of the ordered carbon nanotube film in the carbon nanotube structure is not limited, and the arrangement direction of the carbon nanotubes between two adjacent layers of ordered carbon nanotube films forms an included angle α, 0≤α≤ 90 degrees, which can be prepared according to actual needs. Since the carbon nanotubes in the ordered carbon nanotube film are oriented in the same direction, it has excellent electrical conductivity in the direction in which the carbon nanotubes are arranged. In this embodiment, by changing the intersection angle α between two adjacent layers of ordered carbon nanotube films, the carbon nanotube structure can have excellent electrical conductivity in all directions. In this embodiment, preferably, the intersection angle α=90 degrees.

When the carbon nanotube structure includes at least one carbon nanotube long wire, the carbon nanotube long wire is laid on the surface of the heating layer 16 . The carbon nanotube long wires can be obtained by directly stretching a carbon nanotube array or by twist spinning after stretching a carbon nanotube array. The diameter of the carbon nanotube long line is 1 nanometer to 100 micrometers, and its length is not limited, and can be produced according to actual needs. Please refer to FIG. 4 and FIG. 5 , the carbon nanotube long line includes a plurality of end-to-end connected carbon nanotubes arranged in a preferred orientation along the axial direction of the carbon nanotube long line. Specifically, the carbon nanotubes in the carbon nanotube long line are arranged in parallel along the axial direction of the carbon nanotube long line or arranged helically along the axial direction of the carbon nanotube long line. The carbon nanotubes in the carbon nanotube long line are tightly combined by van der Waals force, so the carbon nanotube long line has certain flexibility. The carbon nanotubes have a length of 200-900 microns.

The carbon nanotube structure may also include a plurality of carbon nanotube long lines, and the plurality of carbon nanotube long lines cross and overlap on the surface of the heating layer 16 . The length, width and thickness of the carbon nanotube structure are not limited, and can be prepared according to actual needs. Since the long wires of carbon nanotubes have certain flexibility, the carbon nanotube structure can be bent and folded into any shape without breaking.

Since the carbon nanotubes in the carbon nanotube long line are arranged along the length direction of the carbon nanotube long line, the carbon nanotube long line has a small resistance along the length direction. Therefore, the carbon nanotube long wire is wound on the surface of the heating layer 16 as an electrode, which can effectively conduct current and save electric energy.

When only one electrode includes a carbon nanotube structure, the other electrode adopts metal sheet metal wire, metal film or conductive glue layer and the like. In this embodiment, preferably, both the first electrode 12 and the second electrode 14 are made of a carbon nanotube structure, and the carbon nanotube structure includes 50 layers of ordered carbon nanotube films overlapping and intersecting, and two adjacent layers are ordered The angle of intersection between the carbon nanotube films is 90 degrees. The ordered carbon nanotube film in the carbon nanotube structure has a length of 1 cm, a width of 1 cm, and a thickness of 30 microns. In this embodiment, the two above-mentioned carbon nanotube structures are respectively wrapped on the surface of the heating layer 16 at intervals. Due to the good electrical conductivity of the carbon nanotube structure, a good electrical connection is formed between the carbon nanotube structure and the heating layer 16 .

In this embodiment, preferably, the heating layer 16 is a carbon nanotube layer. Both the first electrode 12 and the second electrode 14 adopt 10 layers of ordered carbon nanotube films overlapping and intersecting, and the intersection angle between two adjacent layers of ordered carbon nanotube films is 90 degrees. This structure can reduce the ohmic contact resistance between the heating layer 16 and the electrode, and improve the utilization rate of electric energy.

When the surface heat source 10 of the embodiment of the technical solution is in use, the first electrode 12 and the second electrode 14 of the surface heat source 10 can be connected to a wire first and then connected to a power source. After the power is connected, the carbon nanotube layer in the heat source 10 can radiate electromagnetic waves in a certain wavelength range. The surface heat source 10 can be in direct contact with the surface of the object to be heated or set at a certain distance from the object to be heated.

The surface heat source has the following advantages: First, carbon nanotubes have excellent electrical conductivity, so the resistance of the electrode is small, which is beneficial to reduce power consumption and improve heating efficiency. Second, the excellent mechanical properties of carbon nanotubes make the carbon nanotube structure have good flexibility and mechanical strength. Therefore, using the carbon nanotube structure as an electrode can correspondingly improve the durability of the surface heat source, especially the flexible surface heat source. The surface heat source has a long service life; thirdly, the density of carbon nanotubes is small, so the surface heat source is light in weight and easy to use.

In addition, those skilled in the art can also make other changes within the spirit of the present invention. Of course, these changes made according to the spirit of the present invention should be included within the scope of protection claimed by the present invention.

Claims (12)

1. plane heat source, it comprises:

One zone of heating; And

At least two electrodes, this at least two electrode gap settings and electrically contacting with this zone of heating respectively;

It is characterized in that at least one electrode is a carbon nano tube structure in said at least two electrodes, this carbon nano tube structure comprises two superimposed and ordered carbon nanotube film arranged in a crossed manner at least.

2. plane heat source as claimed in claim 1 is characterized in that, said ordered carbon nanotube film comprises that a plurality of CNTs are along same direction arrangement.

3. plane heat source as claimed in claim 1 is characterized in that, the thickness of described ordered carbon nanotube film is 0.01 micron ~ 100 microns.

4. plane heat source as claimed in claim 1 is characterized in that, said ordered carbon nanotube film comprises a plurality of CNTs that join end to end and be arranged of preferred orient along same direction.

5. plane heat source as claimed in claim 1 is characterized in that, connects through Van der Waals force between the described CNT.

6. plane heat source as claimed in claim 1 is characterized in that, closely connects through Van der Waals force between adjacent two ordered carbon nanotube films in the said carbon nano tube structure.

7. plane heat source as claimed in claim 6 is characterized in that, the orientation of the CNT in the described carbon nano tube structure in the adjacent ordered carbon nanotube film forms an angle, 0≤α≤90 degree.

8. plane heat source as claimed in claim 1 is characterized in that said plane heat source further comprises a platy substrate, and said carbon nano tube structure is arranged on this platy substrate surface.

9. plane heat source as claimed in claim 8 is characterized in that, the material of said substrate is flexible material or hard material, and said flexible material is plastics or flexible fiber, and said hard material is pottery, glass, resin or quartz.

10. plane heat source as claimed in claim 1 is characterized in that said plane heat source further comprises a reflector, and this reflector is arranged at the zone of heating surface, and the material in said reflector is metal oxide, slaine or pottery, and thickness is 100 microns ~ 0.5 millimeter.

11. plane heat source as claimed in claim 1 is characterized in that, said plane heat source further comprises a reflector and a platy substrate, and said reflector is arranged between said zone of heating and the substrate or is arranged on the surface of said substrate away from zone of heating.

12. plane heat source as claimed in claim 1 is characterized in that, said plane heat source comprises that further an insulating protective layer is arranged at said zone of heating surface, and the material of said insulating protective layer comprises rubber or resin.

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