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KR-102962065-B1 - Laminated Planar Heating Element Including Recycled Carbon Fiber Dry Nonwoven Fabric and Method for Manufacturing the Same

KR102962065B1KR 102962065 B1KR102962065 B1KR 102962065B1KR-102962065-B1

Abstract

The present invention relates to a planar heating element using a recycled carbon fiber dry nonwoven fabric as a heating element and a method for manufacturing the same. Its technical features lie in the comprehensive improvement of the electrode structure, current distribution structure, and lamination structure to enable uniform heating characteristics and the maintenance of stable output for a long time, even in large-area application environments. Since the recycled carbon fiber dry nonwoven fabric forms a conductive network in which a number of short fibers are dispersed in random directions, the current can naturally flow and be distributed across the entire surface without concentrating in a specific direction or at a specific point. This fundamentally alleviates the problems of current bias and uneven heating that were issues with conventional fabric or felt-type heating elements. The present invention implements a multi-point contact structure for the contact between the heating element and the electrode by arranging a pair of upper planar metal fibers spaced apart on the upper part of the heating element and forming a plurality of fine protrusions on their lower surfaces. Accordingly, fluctuations in contact resistance are suppressed even in environments involving repetitive bending, compression, and thermal cycling, and current flows uniformly into the surface of the heating element. Furthermore, by inserting and contacting a circular metal fiber at the lower center of the upper planar metal fibers through a structure that stabilizes the current inflow point and ensures that the current is evenly distributed along the length of the electrode, the invention effectively prevents overheating of the electrode adjacent area or low temperature at the end area. With such a configuration, the present invention can simultaneously ensure heat uniformity, output stability, and resistance to partial damage without the need for separate sensors or control circuits, and provides a planar heating element that offers high reliability and durability in fields requiring long-term continuous use and harsh environments, such as road snow melting, floor heating, and industrial large-area heating panels.

Inventors

  • 문정우

Assignees

  • 주식회사 에스디에이씨

Dates

Publication Date
20260507
Application Date
20260105

Claims (7)

  1. A heating element (30) including a recycled carbon fiber dry nonwoven fabric; A first thermoplastic polymer film (20) disposed on the upper part of the heating element (30); A second thermoplastic polymer film (40) disposed at the lower part of the heating element (30); A first insulating and heat-resistant film (10) disposed on top of the first thermoplastic polymer film (20); It includes a second insulating and heat-resistant film (50) disposed below the second thermoplastic polymer film (40); The heating element (30), the first and second thermoplastic polymer films (20, 40), and the first and second insulating and heat-resistant films (10, 50) are integrally bonded by a vacuum laminating or thermal calendering process to form the above; A current supply unit (100) is provided that is installed in the heating element (30) before the bonding process and is connected to the heating element (30) in an electrically connected state to supply current to the heating element (30); The above current supply unit (100) has a pair of upper planar metal fibers (110) stacked on the upper surface of the heating unit (30) with a mutual spacing (L) and installed parallel to each other; A plurality of fine protrusions (111) are formed on the lower surface of the pair of upper planar metal fibers (110) stacked on the heating element (30); The length (S) of the micro protrusion (111) protruding downward from the lower surface of the upper planar metal fiber (110) is 120 to 250 μm; The average diameter (d) of the micro-protrusion (111) is 6 to 20 μm; The above micro-protrusions (111) are formed at a density of 150 to 400 pieces/mm² per unit area of the upper planar metal fiber (110); The shape of the above micro-protrusion (111) is conical; A plurality of micro protrusions (111) have different lengths (S) and average diameters (d) of the micro protrusions (111); The above micro protrusions (111) are formed to partially penetrate the surface or interior of the recycled carbon fiber dry nonwoven fabric, thereby suppressing fluctuations in contact resistance between the upper planar metal fiber (110) and the heating element (30); The first and second thermoplastic polymer films (20, 40) above comprise ethylene-vinyl acetate (EVA); A planar heating element comprising a recycled carbon fiber dry nonwoven fabric, characterized in that the first and second insulating and heat-resistant films (10, 50) are composed of one or more of polyimide, fluorine-based resin, or silicone-based resin films.
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  3. In paragraph 1, At the lower center of each of the above pair of upper planar metal fibers (110), a circular metal fiber (120) is installed parallel to the upper planar metal fiber (110); A portion of the body of the above-mentioned circular metal fiber (120) is inserted into the lower surface of the upper surface metal fiber (110), so that the lower portion of the circular metal fiber (120) comes into contact with the upper surface of the heating element (30); The above pair of upper planar metal fibers (110) are connected in an electrically charged state through a circular metal fiber (120); A planar heating element comprising a recycled carbon fiber dry nonwoven fabric, characterized in that a power source (130) is connected to the above circular metal fiber (120).
  4. In paragraph 3, A planar heating element comprising a recycled carbon fiber dry nonwoven fabric, characterized in that the spacing (L) between the pair of upper planar metal fibers (110) is calculated according to the following relationship based on the surface resistance (Rs) of the dry nonwoven fabric, electrode length (W), power supply voltage (V), and target power (P). L = (V² / P) × (W / Rs)
  5. In paragraph 4, a heating element (30) installed at the bottom of the circular metal fiber (120) has a through hole (31) formed in the vertical direction; A planar heating element comprising a recycled carbon fiber dry nonwoven fabric, characterized in that the through hole (31) is filled with a conductive adhesive (32).
  6. In paragraph 5, A planar heating element comprising a recycled carbon fiber dry nonwoven fabric, characterized in that an upper conductive adhesive layer (140) covering the upper surface of each upper planar metal fiber (110) is formed on the upper surface of each of the pair of upper planar metal fibers (110).
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Description

Laminated Planar Heating Element Including Recycled Carbon Fiber Dry Nonwoven Fabric and Method for Manufacturing the Same The present invention relates to a planar heating element, and more specifically, to a planar heating element using a dry nonwoven fabric formed of recycled carbon fiber as a heating element and a method for manufacturing the same. In particular, the present invention relates to a planar heating element having a laminated structure and a current supply structure capable of improving electrical contact stability between an electrode and a heating element and realizing uniform heating characteristics over the entire surface. Conventional planar heating elements are widely known to utilize carbon fiber fabric, felt, metal heating wire, or a conductive coating layer as the heating element, and these heating elements are applied in various fields such as heating, snow and ice removal, industrial heating, and heating of building interior and exterior materials. However, in the case of fabric-type heating elements, current bias is prone to occur depending on the fiber arrangement direction, leading to a problem of reduced heating uniformity; in the case of felt-type heating elements, non-uniform contact resistance between the electrode and the heating element causes localized low-temperature or overheated areas to form. Furthermore, when planar heating elements are used for purposes such as road snow melting as in the present invention, there is also a problem where heating characteristics become unstable due to changes in contact resistance at the electrode contact area caused by repeated bending, compression, or prolonged use. In particular, in structures where the electrode simply contacts the surface of the heating element or is connected by an adhesive, the current distribution in the lower region of the electrode becomes non-uniform, resulting in reduced heating efficiency and temperature deviation. FIG. 1 is a cross-sectional view illustrating a laminated structure comprising a heating element (30) including a recycled carbon fiber dry nonwoven fabric of the present invention, a first thermoplastic polymer film (20) disposed on the upper part of the heating element (30), a second thermoplastic polymer film (40) disposed on the lower part of the heating element (30), a first insulating and heat-resistant film (10) disposed on the upper part of the first thermoplastic polymer film (20), and a second insulating and heat-resistant film (50) disposed on the lower part of the second thermoplastic polymer film (40). FIG. 2 is a perspective view illustrating a laminated structure comprising a heating element (30) including a recycled carbon fiber dry nonwoven fabric of the present invention, a first thermoplastic polymer film (20) disposed on the upper part of the heating element (30), a second thermoplastic polymer film (40) disposed on the lower part of the heating element (30), a first insulating and heat-resistant film (10) disposed on the upper part of the first thermoplastic polymer film (20), and a second insulating and heat-resistant film (50) disposed on the lower part of the second thermoplastic polymer film (40). FIG. 3 is a plan view illustrating a pair of upper planar metal fibers (110) stacked and installed on the upper part of the heating element (30) of the present invention, and a current supply unit (100) that supplies current to the heating element (30). FIG. 4a is a schematic diagram (a plan view of the lower surface of the planar metal fiber) showing that a plurality of fine protrusions (111) are formed on the lower surface of the upper planar metal fiber (110) of the present invention. FIG. 4b is a schematic diagram (side view) of a structure in which a plurality of fine protrusions (111) are formed on the lower surface of the upper planar metal fiber (110) of the present invention, enlarged under a microscope. FIG. 5 is a plan view showing a pair of upper planar metal fibers (110) stacked and installed on the upper part of the heating part (30) of the present invention and a current supply unit (100) that supplies current to the heating part (30). It shows a structure in which a part of the body of a circular metal fiber (120) is inserted into the lower surface of the upper planar metal fiber (110), and the lower part of the surface of the circular metal fiber (120) is in contact with the upper surface of the heating part (30). FIG. 6 is a cross-sectional view of the CC in FIG. 5, showing a structure in which a part of the body of the circular metal fiber (120) is inserted into the lower surface of the upper surface metal fiber (110), and the lower part of the surface of the circular metal fiber (120) is in contact with the upper surface of the heating element (30). FIG. 7 is a schematic diagram (a plan view of the lower surface of the planar metal fiber) showing that a plurality of fine protrusions (111) are formed on the lower surface of the upper planar metal fiber (11