KR101763658B1 - Flat flexible electric resistance heating element and method fabricating thereof - Google Patents

Flat flexible electric resistance heating element and method fabricating thereof Download PDF

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Publication number
KR101763658B1
KR101763658B1 KR1020160030139A KR20160030139A KR101763658B1 KR 101763658 B1 KR101763658 B1 KR 101763658B1 KR 1020160030139 A KR1020160030139 A KR 1020160030139A KR 20160030139 A KR20160030139 A KR 20160030139A KR 101763658 B1 KR101763658 B1 KR 101763658B1
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South Korea
Prior art keywords
stretchable
heating element
resistance heating
conductive layer
electric resistance
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KR1020160030139A
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Korean (ko)
Inventor
서동석
이유락
이영희
김정균
Original Assignee
성균관대학교산학협력단
기초과학연구원
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Priority to KR1020160030139A priority Critical patent/KR101763658B1/en
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/20—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater
    • H05B3/34—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater flexible, e.g. heating nets or webs
    • H05B3/36—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater flexible, e.g. heating nets or webs heating conductor embedded in insulating material
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/10—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
    • H05B3/14—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
    • H05B3/145—Carbon only, e.g. carbon black, graphite
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/10—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/18—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor the conductor being embedded in an insulating material
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/009—Heaters using conductive material in contact with opposing surfaces of the resistive element or resistive layer
    • H05B2203/01—Heaters comprising a particular structure with multiple layers
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/013—Heaters using resistive films or coatings
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/017—Manufacturing methods or apparatus for heaters

Abstract

The present invention relates to a planar stretchable electric resistance heating element, and a manufacturing method thereof. According to the present invention, the planar stretchable electric resistance heating element has structural stability and a uniform heat transfer effect compared to an existing heating wire type heating element, and also has a stable circuit structure since resistance is not changed even though the heating element is stretched. Therefore, the planar stretchable electric resistance heating element, which can be freely bent and stretched, can be attached to a complex structure or shape to transfer heat, and is resistant to external force to increase service life. In addition, the planar stretchable electric resistance heating element has significantly less weight and requires a lower driving voltage than the existing heating element to be used as portable heating equipment or a wearable element when connected to a battery. The planar stretchable electric resistance heating element comprises: a stretchable substrate; a heat transfer layer; and an electrode.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a flat type elastic electric resistance heating element,

The present invention relates to a planar stretchable electric resistance heating element and a manufacturing method thereof. In the present invention, by using a flat elongated heating element, the heating element has a structural stability and a uniform heat transfer effect, and the resistance is not changed even when the heating element is elongated.

The heating elements using the common metal have problems in that they can not be stretched due to the inherent stiffness of the metal, and when the continuous or repetitive external force acts, the heating wire is cut off and can not be operated any more.

In the case of the heating element of the conventional hot-wire type, there is a risk of fire due to generation of high heat when the resistance of the heating element is locally increased as the heating wire is stretched or partially cut.

On the other hand, in the case of a heating element using a heating wire having a fabric shape or fluidity, since the heating element does not stretch while the main body is elongated even if the structure is stretchable, the area in which the heating element does not adjoin is widened, .

Even if the elastic body is stretched as described above, if the resistance is greatly changed as the heating element is increased, the circuit is difficult to design and unstable, and when the same voltage is applied by a simple circuit, the heating power increases, Which is a problem in that a sufficient heat generating effect can not be obtained.

A heating element using a jelly generated by flowing a current to a resistor has been commercialized for a long time. Nowadays, it is used not only in the function of the heating device, but also in various fields such as production of materials synthesis and production, medical equipment, aerospace equipment, and the like. Particularly, a flexible heating element capable of adjusting its shape so as to be installed in almost all equipment and facilities such as complex appearance, shape, curvature and piping is attracting attention. Accordingly, a silicone rubber heating element made by inserting a metal fiber glass or a patterned valve into a flexible substrate using silicone rubber has been developed.

However, as already mentioned above, the nickel and nichrome resistors used as the hot wire can be bent or stretched within a small range, but due to the stiffness of the material itself, the tensile force is exceeded due to the external force, In case of damage, as the resistance increases, the temperature increases locally and there is a risk of fire. In addition, since the resistor is manufactured in a structure in which the entire heating element circulates through a single line, there is a problem that if the heating element is damaged even in a certain section, the entire heating element is prevented from operating.

SUMMARY OF THE INVENTION [0006] The present invention is directed to provide a planar stretchable electric resistance heating element and a method of manufacturing the same, in order to solve the problem that the flexible body and the flexible body mentioned above can not be expanded and contracted together with the main body.

According to the present invention, it is possible to provide a structure capable of continuously operating even if a part is broken or deformed by an external force and having a uniform heat transfer effect over the whole plane by manufacturing a planar stretchable electric resistance heating body capable of being freely deformed . In addition, a structure capable of sustaining heat transfer with little change in resistance due to deformation is disclosed.

A method of manufacturing a planar stretchable electrical resistance heating element according to an embodiment of the present invention includes: preparing a flexible substrate; Expanding the stretchable substrate to a constant elongation; Attaching a conductive layer on the stretched elastic substrate; Attaching electrodes to both ends of the conductive layer; Covering the conductive layer with a stretchable material in a liquid state; And compressing the elongated liquid material after restoring the stretched elastic substrate to its original length.

The stretchable substrate and the stretchable material are stretchable polymer materials, and the conductive layer is preferably sheet-shaped and flexible, and preferably sheet-shaped carbon nanotubes are used.

And forming an electrode protection layer after the step of attaching the electrodes to both ends of the conductive layer, wherein the electrode protection layer is formed by covering the electrode with a stretchable material in a liquid state and then hardening.

A planar stretchable electric resistance heating body according to an embodiment of the present invention includes: a flexible substrate; A conductive layer on said flexible substrate; Electrodes attached to both ends of the conductive layer; And a stretchable material layer covering the conductive layer, wherein the conductive layer is attached after the stretchable substrate is stretched to a predetermined elongation, and the stretchable material layer covering the conductive layer is coated with a stretchable material in a liquid state, To the original length.

Preferably, the flexible substrate and the stretchable material are stretchable polymer materials, and the conductive layer is sheet-shaped and flexible.

The electrode protection layer may further include an electrode protection layer for protecting the electrode, and the electrode protection layer may be made of a stretchable material that surrounds the electrode.
Wherein the planar stretchable electrical resistance heating body includes a ratio of length to length that is 0 to 600%, wherein the resistance change of the conductive layer of the planar stretchable electrical resistance heating body ranges from 0 to 100% .

And a housing for applying a tensile force to extend and retract the planar stretchable electric resistance heating element, wherein the housing has a shape for wrapping and fixing the planar stretchable electric resistance heating body, and is connected to the planar stretchable electric resistance heating body.

The position where the housing is connected to the flat elastic electric heating element is located on the inner surface side of the electrode protection layer so that when the tensile force is applied to the elastic electric resistance heating element through the housing from the outside, So that the contact between the conductive layer and the electrode is maintained.

A planar stretchable electric resistance heating body according to a further embodiment of the present invention comprises: a flexible substrate; A conductive layer on said flexible substrate; Electrodes attached to both ends of the conductive layer; And a layer of a stretchable material covering the conductive layer, the step of preparing the stretchable substrate; Expanding the stretchable substrate to a constant elongation; Attaching a conductive layer on the stretched elastic substrate; Attaching electrodes to both ends of the conductive layer; Covering the conductive layer with a stretchable material in a liquid state; And restoring the stretched elastic substrate to its original length and then solidifying the liquid stretchable material.

Preferably, the flexible substrate and the stretchable material are stretchable polymer materials, and the conductive layer is sheet-shaped and flexible.

Wherein the electrode protection layer is formed of a stretchable material that surrounds the electrode, and the stretchable material that surrounds the electrode includes a step of attaching electrodes to both ends of the conductive layer, The electrode is formed by covering with an elastic material in a liquid state and then hardening.

According to the present invention, a flexible electric resistance heating element can be manufactured and bent or stretched freely, so that it can be attached to a complicated structure or shape to transmit heat, and the possibility of failure due to an external force is small. At the same time, the weight is significantly lower than the conventional heating element and the driving voltage is low, so that it can be used as a portable heating device or a wearable device when the battery is connected.

1 shows a flowchart of a method of manufacturing a planar stretchable electric resistance heating element according to an embodiment of the present invention.
2 is a plan view of a method of manufacturing a planar stretchable electric resistance heating element according to an embodiment of the present invention.
Fig. 3 is a schematic view of a planar stretchable electric resistance heating element according to an embodiment of the present invention.
Fig. 4 shows a cross-sectional view of a planar stretchable electric resistance heating element according to a further embodiment of the present invention.
5 shows a cross-sectional view of a planar stretchable electric resistance heating element according to a further embodiment of the present invention.
FIG. 6 is a diagram illustrating a method of measuring a heat ray generated by applying a voltage to a heating element manufactured according to an embodiment of the present invention by using a thermal imaging camera.
Fig. 7 shows a stepwise increase of the fabricated planar stretchable electric resistance heating body from the original length to 2.5 times.
FIG. 8 shows an increased surface temperature profile of a heating element while applying a stepwise high voltage from 5 V to 30 V to the heating element of FIG.
9 is a photograph of a heating element taken with a thermal imaging camera after 5 minutes with a voltage applied to the heating element.
10 is data obtained by measuring a temperature of a surface of a heating element which changes with the passage of time by applying a voltage of 30 V in a state where the heating element is stretched.
11 is a view showing a problem which occurs when the contact between the electrode and the conductive layer is poor as a comparative example.
FIG. 12 shows a heating element manufactured by changing the number of carbon nanotube sheets used as the conductive layer.
13 is a graph showing a change in temperature on the surface of a heating element generated when a voltage of 10 V is applied to the four heating elements shown in FIG.
FIG. 14 shows a state in which a stretchable heating element is wrapped in a glass bottle containing water, and a photograph in which a glass bottle heated by applying a current to a heating element is measured with a thermal camera and temperature data.
FIG. 15 shows a state where a heating element is attached to a side of a plastic bottle containing ice in a freezing chamber, and a voltage is applied for 1 hour to dissolve the ice.
Various embodiments are now described with reference to the drawings, wherein like reference numerals are used throughout the drawings to refer to like elements. For purposes of explanation, various descriptions are set forth herein to provide an understanding of the present invention. It is evident, however, that such embodiments may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing the embodiments.

The following description provides a simplified description of one or more embodiments in order to provide a basic understanding of embodiments of the invention. This section is not a comprehensive overview of all possible embodiments and is not intended to identify key elements or to cover the scope of all embodiments of all elements. Its sole purpose is to present the concept of one or more embodiments in a simplified form as a prelude to the more detailed description that is presented later.

The present invention proposes a heating element using a flat conductive flexible layer so that continuous and uniform heat transfer is possible without sacrificing efficiency or reliability while allowing flexible or stretchable flexible substrates to cover the conductive layer. In addition, unlike the conventional heat wire structure, a resistor connected in a planar shape is provided, which does not have a large influence on the performance of the entire heating element even when a specific portion is damaged, and has a structure that is electrically stable even with a small amount of current flowing through the isolated portion .

Hereinafter, the contents of the present invention will be described in detail with reference to the drawings.

2 is a schematic plan view of a method of manufacturing a planar stretchable electrical resistance heating element according to an embodiment of the present invention; FIG. 2 is a schematic plan view of a method of manufacturing a planar stretchable electrical resistance heating element according to an embodiment of the present invention; do.

A method of manufacturing a planar stretchable electric resistance heating element according to an embodiment of the present invention includes: preparing a flexible substrate (S 110); Expanding the stretchable substrate to a predetermined stretch ratio (S 120); Attaching a conductive layer on the stretched elastic substrate (S 130); Attaching electrodes to both ends of the conductive layer (S 140); Covering the conductive layer with a stretchable material in a liquid state (S 150); And a step (S 160) of consolidating the stretchable liquid material after restoring the elongated stretchable substrate to its original length.

In step S 110, a stretchable substrate is prepared. The stretchable substrate can be any substrate having stretchability. The stretchable substrate includes all stretchable polymers. For example, PDMS and Ecoflex. Such a stretchable substrate is preferable as the bonding property with the conductive layer becomes better, and the good bonding property means that the adhesion between the two materials is excellent and thus the film has structural stability.

In step S 120, the prepared stretchable substrate is stretched to a predetermined elongation. A stretchable substrate made of a stretchable material has a maximum elongation according to the material used and stretches the elongated substrate to a desired elongation within an allowable elongation range.

According to the present invention, since a flexible conductive layer is attached and covered with a stretchable material layer again in the state where the flexible substrate is stretched as described later, when the stretchable substrate is reduced to its original length, And when the stretchable substrate is stretched again, the conductive layer is restored to a flat state at the time of attachment. That is, the conductor thus manufactured has structural stability against repeated elongation and contraction within the elongation limit of the stretchable substrate when it is initially attached.

In step S 130, the conductive layer is attached on the stretched elastic substrate. The conductive layer is preferably flexible and has a sheet-like shape. Materials that can be used as such a conductive layer include all metal materials capable of forming thin films by various deposition methods used in semiconductor processing. For example, Au and Ag.

Alternatively, the conductive layer may be formed by spraying nanomaterials such as metal nanoparticles or nanowires dispersed in a solvent, or by dispersing a solution in which a carbon nanotube sheet is adhered to a flexible substrate.

In step S 140, electrodes are attached to both ends of the conductive layer. By applying such a voltage to the conductive layer through the attachment of the electrodes, it is possible to generate a juxtaposition.

On the other hand, after the step of attaching the electrodes to both ends of the conductive layer, a step of forming the electrode protective layer may be further included. The electrode protection layer is formed by covering the electrode with a stretchable material in a liquid state and then hardening it. By covering the electrode with a stretchable material in a liquid state and then solidifying it, it can act as a protective film to prevent the bond between the conductive layer and the electrode from being broken when the stretchable substrate is reduced to its original length or stretched again. The stretchable material includes all polymers having stretchability. For example, PDMS and Ecoflex. This will be further described in the following description of the structure.

In step S 150, the conductive layer is covered with a liquid-state stretchable material. If the electrode is covered with a liquid-state stretchable material and then hardened as described in step S 140, another liquid-state stretchable material Thereby covering the entire conductive layer.

The liquid, stretchable material used is then solidified by subsequent consolidation in step S 160, and the stretchable material includes all of the stretchable polymer. For example, PDMS and Ecoflex.

In step S 160, after stretching the stretchable substrate to its original length, the liquid stretchable material is hardened.

When a conductive layer is attached on a previously stretchable substrate and then a stretchable material in the form of a liquid is covered thereon and then the substrate is compacted to the original length, There is an effect of reducing a change in resistance caused by abutment. That is, the stretchable substrate covering the conductive layer not only serves to insulate the conductive layer from the outside, but also has an insulating function between the conductive layers.

In summary, in the present invention, when a flexible conductive layer is attached in a state in which the flexible substrate is stretched, and the flexible substrate is covered with the stretchable material layer again after the flexible substrate is stretched in its original length, the stretchable material layer is hardened. The conductive layer thus shrinks to form a wrinkle shape. When the stretchable substrate is stretched again, the conductive layer is restored to a flat shape at the time of adhering. That is, the conductor thus manufactured has structural stability against repeated elongation and contraction within the elongation limit of the stretchable substrate when it is initially attached.

Hereinafter, a planar stretchable electric resistance heating element according to an embodiment of the present invention will be described in further detail with reference to the drawings, and repetitive explanations of portions overlapping with those described above will be omitted.

Fig. 3 is a schematic view of a planar stretchable electric resistance heating element according to an embodiment of the present invention.

A planar stretchable electric resistance heating body according to an embodiment of the present invention includes a flexible substrate 10; A conductive layer (20) on the flexible substrate; Electrodes 30 attached to both ends of the conductive layer; And a stretchable material layer 40 covering the conductive layer.

The stretchable substrate 10 and the stretchable material layer 40 can be stretchable polymeric materials and can be the same or different materials. Further, it is preferable that such a stretchable material has excellent bonding property with the conductive layer. Such stretchable materials can not be used for electricity but can be selected for use with heat-resistant materials and heat-insensitive materials.

There are two main uses of the elastic cover 40. The first is to reduce the resistance change due to the expansion and contraction of the heater, and the second is to protect and isolate the conductive layer from the outside with the nonconductive material. As for the thickness of the stretchable material layer 40, the strips from the conductive material are transmitted through the lid. Thinner the thickness is, the more the heat is transmitted. Therefore, the thickness is controlled according to the use of the heater.

The conductive layer 20 on the flexible substrate is preferably sheet-shaped and has flexibility. A representative material that can be used as the conductive layer is a carbon nanotube sheet. The conductive layer may have a rectangular shape and may have various shapes.

The resistance of the conductive layer decreases as the number of layers increases. When the same voltage is applied, more current flows to increase the amount of heat generated. That is, if the number of conductive layers is increased or another conductive material is added to the conductive layer to lower the resistance, a high calorific value can be obtained in an environment where the same voltage can be applied.

For example, when a carbon nanotube sheet is used as a conductive layer, if the number of carbon nanotube sheets is increased or another conductive material is added to the conductive layer to lower the resistance, a high calorific value Can be obtained.

When a battery is connected to a general heating element, the same voltage is applied to the resistor irrespective of the resistance. If the resistance is greatly increased as the conductor increases, the current decreases in inverse proportion to the resistance, . This is because as the stretchable substrate is stretched, the surface area of the conductive layer is widened, and the amount of electric power relative to the area is decreased. As a result, the heat generated is reduced and the heat generation effect is significantly reduced. However, when the resistance change is constant such as a carbon nanotube sheet, The heat generation effect is reduced, so that it is possible to generate a relatively larger amount of heat even at a high elongation.

The carbon nanotube sheet used in the present invention includes a material described in International Journal of Science, titled " Strong, Transparent, Multifunctional, Carbon Nanotube Sheets ", and the multiwalled carbon nanotube bundles are entangled in one direction . If it is wound using a support, it can be fabricated as a thin surface. If it is repeatedly wound on a support as needed, a multi-layered carbon nanotube sheet can be obtained.
The planar stretchable electric resistance heating element according to an embodiment of the present invention includes a ratio of the length to the length of the elongated electric resistance heating element in the range of 0 to 600%, wherein the resistance before the increase in the resistance of the conductive layer of the planar stretchable electric resistance heating element Value ranges from 0 to 100%.

The electrode 30 is not particularly limited as long as it is usable as an electrode material. Since the electrode 30 is connected to the conductive layer 20 to apply a voltage to the conductive layer to generate juxtaposition, the connection between the electrode 30 and the conductive layer 20 is not broken during the expansion and contraction of the heating element, Is a very important part in the reliability of the apparatus. The electrode 30 is connected to the conductive layer 20 through the conductive adhesive 32. The present invention discloses an electrode protection layer and a housing structure for maintaining connection between the electrode 30 and the conductive layer 20 in connection with the heating element, which will be described later.

The conductive layer 20 is attached after the flexible substrate 10 is stretched to a certain extension ratio and the stretchable material layer 40 covering the conductive layer restores the flexible substrate 10 to its original length after applying the stretchable material in a liquid state After that, it was solidified.

According to the present invention, since the flexible conductive layer is attached in a state in which the flexible substrate is stretched and the flexible substrate is covered with the stretchable material layer and then the flexible substrate is shrunk to the original length again, the stretchable material layer is hardened. The layer is shrunk to form a wrinkle shape, and when the stretchable substrate is stretched again, the conductive layer is restored to a flat shape at the time of attachment.

Therefore, although the planar stretchable electric resistance heating body according to an embodiment of the present invention has a high elasticity, the resistance of the electric conductor does not change with elongation, so that it has stability against the circuit configuration.

As described above, according to an embodiment of the present invention, the electrode protection layer may further include an electrode protection layer for protecting the electrode 30, and the electrode protection layer is made of a stretchable material that surrounds the electrode.

4 illustrates a cross-sectional view of a planar stretchable electric resistance heating element according to a further embodiment of the present invention. As shown in FIG. 4, the electrode protection layer 50 is made of a stretchable material that surrounds the electrode 30 to protect the electrode 30.

Even if the heating element is expanded or contracted through the electrode protection layer, the connection between the conductor and the electrode can be maintained reliably and continuously.

Meanwhile, according to a further embodiment of the present invention, in addition to the electrode protection layer, it may be structurally designed to maintain the connection between the conductor and the electrode, as shown in Fig.

As shown in Fig. 5, the planar stretchable electric resistance heating body according to a further embodiment of the present invention further includes a housing 60 for applying a tensile force to stretch the planar stretchable electric resistance heating body.

The housing 60 has a shape for enclosing and fixing a planar stretchable electrical resistance heating element, which is connected to a planar stretchable electrical resistance heating element.

On the other hand, when the housing 60 is connected, the housing is connected to the body of the heating element through the film layer 70. This film layer 70 may be a Kapton film, for example, which serves as a protective layer of such a flexible substrate when the housing captures the flexible substrate in the form of a forceps.

5, by pulling the housing 60, it becomes possible to expand and contract the stretchable electric resistance heating element without affecting the electrode 30 and the electrode protecting layer 50. To this end, the position where the housing 60 is connected to the flat elastic electric heating element is located on the inner surface side of the electrode protection layer 50 so that the contact between the conductive layer and the electrode is maintained.

5, when the housing is pulled, a tensile force is not applied to the electrode protection layer 50 at all and a tensile force is exerted only inside the position where the electrode protection layer is disposed in the heating element.

The present invention is not limited to a heating element having a uniform resistance over a plane as a flat heating element structure, but also a heating type can be changed by making resistance different according to the purpose.

According to another embodiment of the present invention, there is provided a planar stretchable electric resistance heating element comprising: a flexible substrate; A conductive layer on said flexible substrate; Electrodes attached to both ends of the conductive layer; And a layer of a stretchable material covering the conductive layer, the step of preparing the stretchable substrate; Expanding the stretchable substrate to a constant elongation; Attaching a conductive layer on the stretched elastic substrate; Attaching electrodes to both ends of the conductive layer; Covering the conductive layer with a stretchable material in a liquid state; And restoring the stretched elastic substrate to its original length and then solidifying the liquid stretchable material.

Preferably, the flexible substrate and the stretchable material are stretchable polymer materials, and the conductive layer is sheet-shaped and flexible.

Wherein the electrode protection layer is formed of a stretchable material that surrounds the electrode, and the stretchable material that surrounds the electrode includes a step of attaching electrodes to both ends of the conductive layer, The electrode is formed by covering with an elastic material in a liquid state and then hardening.

Hereinafter, the contents of the present invention will be described in detail with concrete examples.

Electric resistive heating elements were fabricated by using Ecoflex0010 (Smooth-on co.) As a stretch substrate and carbon nanotube sheet as a conductive layer in the same order as in FIGS. 1 and 2.

Then, as shown in FIG. 6, a voltage was applied through the power supply to measure the temperature change occurring in the heating element with an IR camera (FLIR co. Model I3). FIG. 6 is a view showing a state in which a string of LEDs generated by applying a voltage to a heating element manufactured according to an embodiment of the present invention is measured by a thermal imaging camera. FIG. And shows an increasing surface temperature profile of the heating element. 7, it can be seen that the surface temperature of the heating element becomes higher as the applied voltage is higher in a state where the heating element is not extended. As a result, it was confirmed that the heating element manufactured by this method shows a stable operation state of the heating element up to 30V.

FIG. 8 shows a state in which the planar stretchable electric resistance heating element is stepwise increased from the original length to 2.5 times. As shown in FIG. Black is a conductive layer, and a translucent flexible substrate is attached up and down.

The temperature change when the applied voltage was differently applied in a state in which the heating element was not extended was observed in FIG. 7, and the graph of the temperature change and the graph of the temperature change were shown in FIGS. 9 and 10 Respectively.

FIG. 9 is a photograph of a heating element taken with a thermal imaging camera 5 minutes after a voltage is applied to a heating element, and it can be seen that heat is uniformly distributed throughout the extended conductive layer. 10 is data obtained by measuring a temperature of a surface of a heating element which changes with the passage of time by applying a voltage of 30 V in a state where the heating element is stretched. It was confirmed that even though the heating body was stretched to 250%, the manufactured heating body showed a stable operation state.

Fig. 11 shows a problem which occurs when the contact between the electrode and the conductive layer is poor, as a comparative example. 11 (A) is a heating element manufactured without a conductive adhesive between a conductive layer and an electrode. When a voltage is applied to the heating element to generate a joule heat, a photograph measured by a thermal imaging camera is on the left side of (B) The picture measured in the stretched state is the right side of (B). Since the contact resistance between the electrode and the conductive layer is high, a high voltage is applied, and a locally high heat is generated. As a result, heat is not generated throughout the heating element, and heat is generated between the electrode and the conductive layer, so that uniform heat transfer can not be performed. This is more evident when the heating element is increased. Therefore, it is preferable to fix the conductive layer and the electrode with a conductive adhesive agent as shown in FIG. 4 of the present invention, and to prevent the contact portion from being damaged even when repeatedly covering the protective layer.

FIG. 12 shows a heating element manufactured by changing the number of carbon nanotube sheets used as the conductive layer, and each of the conductive layers was formed of a conductive layer made of carbon nanotube sheets of 10 layers, 40 layers, 60 layers, and 100 layers, The resistance is different.

13 is a graph showing a change in temperature on the surface of a heating element generated when a voltage of 10 V is applied to the four heating elements shown in FIG. As the number of layers of the carbon nanotube sheet increases, resistance decreases. When the same voltage is applied, more current flows and the amount of heat generation increases. That is, it has been confirmed that when the number of carbon nanotube sheets of the conductive layer is increased or another conductive material is added to the conductive layer to lower the resistance, a high calorific value can be obtained in an environment where the same voltage can be applied.

 14 (A) shows a state in which a stretchable heating element is wrapped in a glass bottle containing water, and a glass bottle in which a current is supplied to a heating body and the glass bottle is measured with an infrared camera. FIG. 14 (B) is a graph showing the temperature of the water in the glass bottle to be heated, which shows that the water reaches the boiling point after 10 minutes from the application of the voltage.

FIG. 15 shows a state where a heating element is attached to a side of a plastic bottle containing ice in a freezing chamber, and a voltage is applied for 1 hour to dissolve the ice. Even in extreme environments in the freezer (the freezer door starts at 0 ° C to open the camera and the temperature goes down to -17 ° C after 1 hour and the thermometer turns off automatically after 30 minutes) It can be melted.

The description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features presented herein.

Claims (18)

Preparing a flexible substrate;
Expanding the stretchable substrate to a constant elongation;
Attaching a conductive layer on the stretched elastic substrate;
Attaching electrodes to both ends of the conductive layer;
Covering the conductive layer with a stretchable material in a liquid state; And
Stretching the stretchable substrate to its original length and then solidifying the stretchable liquid material.
(Method for manufacturing a planar stretchable electric resistance heating element).
The method according to claim 1,
Wherein the stretchable substrate and the stretchable material are stretchable polymer materials,
(Method for manufacturing a planar stretchable electric resistance heating element).
The method according to claim 1,
Wherein the conductive layer is in sheet form and has flexibility.
(Method for manufacturing a planar stretchable electric resistance heating element).
The method according to claim 1,
Further comprising the step of forming an electrode protection layer after attaching electrodes to both ends of the conductive layer,
Wherein the electrode protection layer is formed by covering the electrode with a stretchable material in a liquid state and then hardening the electrode,
(Method for manufacturing a planar stretchable electric resistance heating element).
A stretchable substrate;
A conductive layer on said flexible substrate;
Electrodes attached to both ends of the conductive layer; And
And a stretchable material layer covering the conductive layer,
Wherein the conductive layer is attached after the stretchable substrate is stretched to a predetermined elongation,
Wherein the stretchable material layer covering the conductive layer is formed by applying a stretchable material in a liquid state, then restoring the stretchable substrate to its original length,
Flat type elastic electric resistance heating element.
6. The method of claim 5,
Wherein the stretchable substrate and the stretchable material are stretchable polymer materials,
Flat type elastic electric resistance heating element.
6. The method of claim 5,
Wherein the conductive layer is a sheet-shaped carbon nanotube,
Flat type elastic electric resistance heating element.
6. The method of claim 5,
Wherein the planar stretchable electrical resistance heating element includes a ratio of a length to an elongated length of 0 to 600%, wherein a change in resistance of the conductive layer of the planar stretchable electrical resistance heating element is 0 to 100% Range,
Flat type elastic electric resistance heating element.
6. The method of claim 5,
Further comprising an electrode protection layer for protecting the electrode,
Wherein the electrode protection layer is made of a stretchable material that surrounds the electrode,
Flat type elastic electric resistance heating element.
6. The method of claim 5,
Further comprising a housing for applying a tensile force to expand and contract the planar stretchable electrical resistance heating element,
Wherein the housing has a shape that surrounds and fixes the planar stretchable electrical resistance heating element, and is connected to the planar stretchable electrical resistance heating element,
Flat type elastic electric resistance heating element.
10. The method of claim 9,
Further comprising a housing for applying a tensile force to expand and contract the planar stretchable electrical resistance heating element,
Wherein the housing has a shape that surrounds and fixes the planar stretchable electrical resistance heating element, and is connected to the planar stretchable electrical resistance heating element,
Flat type elastic electric resistance heating element.
12. The method of claim 11,
Wherein a position where the housing is connected to the flat elongation-resistant electric resistance heating element is located on an inner surface side of the position of the electrode protection layer and when a tensile force is applied to the elongation electric resistance heating body through the housing from the outside, So that contact between the conductive layer and the electrode is maintained,
Flat type elastic electric resistance heating element.
6. The method of claim 5,
Wherein the conductive layer has a plurality of layers,
Flat type elastic electric resistance heating element.
6. The method of claim 5,
A conductive material is added to the conductive layer,
Flat type elastic electric resistance heating element.
A stretchable substrate; A conductive layer on said flexible substrate; Electrodes attached to both ends of the conductive layer; And a stretchable material layer covering the conductive layer,
Preparing the flexible substrate;
Expanding the stretchable substrate to a constant elongation;
Attaching a conductive layer on the stretched elastic substrate;
Attaching electrodes to both ends of the conductive layer;
Covering the conductive layer with a stretchable material in a liquid state; And
The stretchable substrate is restored to its original length and then the stretchable liquid material is hardened,
Flat type elastic electric resistance heating element.
16. The method of claim 15,
Wherein the stretchable substrate and the stretchable material are stretchable polymer materials,
Flat type elastic electric resistance heating element.
16. The method of claim 15,
Wherein the conductive layer is in sheet form and has flexibility.
Flat type elastic electric resistance heating element.
16. The method of claim 15,
Further comprising an electrode protection layer for protecting the electrode,
Wherein the electrode protection layer is made of a stretchable material that surrounds the electrode,
Wherein the stretchable material surrounding the electrode is formed by covering the electrode with a stretchable material in a liquid state and then hardening the electrode after attaching electrodes to both ends of the conductive layer,
Flat type elastic electric resistance heating element.
KR1020160030139A 2016-03-14 2016-03-14 Flat flexible electric resistance heating element and method fabricating thereof KR101763658B1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20190057811A (en) 2017-11-20 2019-05-29 한국생산기술연구원 Stretchable temperature sensor using carbon nanotube sheets and manufacturing method thereof

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002270343A (en) * 2001-03-14 2002-09-20 Matsushita Electric Ind Co Ltd Flat heater body

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002270343A (en) * 2001-03-14 2002-09-20 Matsushita Electric Ind Co Ltd Flat heater body

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20190057811A (en) 2017-11-20 2019-05-29 한국생산기술연구원 Stretchable temperature sensor using carbon nanotube sheets and manufacturing method thereof

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