WO2021221253A1 - Piezoelectric energy harvester having improved durability - Google Patents

Piezoelectric energy harvester having improved durability Download PDF

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Publication number
WO2021221253A1
WO2021221253A1 PCT/KR2020/016317 KR2020016317W WO2021221253A1 WO 2021221253 A1 WO2021221253 A1 WO 2021221253A1 KR 2020016317 W KR2020016317 W KR 2020016317W WO 2021221253 A1 WO2021221253 A1 WO 2021221253A1
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substrate
energy harvester
elastic body
piezoelectric element
piezoelectric
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PCT/KR2020/016317
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French (fr)
Korean (ko)
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유홍희
김민지
정신우
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한양대학교 산학협력단
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
    • H02N2/00—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
    • H02N2/18—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing electrical output from mechanical input, e.g. generators
    • H02N2/186—Vibration harvesters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
    • H02N2/00—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
    • H02N2/18—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing electrical output from mechanical input, e.g. generators
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/30—Piezoelectric or electrostrictive devices with mechanical input and electrical output, e.g. functioning as generators or sensors

Definitions

  • the present invention relates to a piezoelectric energy harvester, and more particularly, to a piezoelectric energy harvester with improved durability.
  • Energy harvesting technology refers to a technology that collects energy wasted in daily life, such as vibration, light, heat, and electromagnetic waves, and converts it into usable electrical energy, and active research is being conducted in various fields.
  • a piezoelectric material is a material that generates electrical energy when subjected to mechanical force or can cause mechanical deformation when subjected to electrical energy.
  • a material such as GaN may be used.
  • the piezoelectric body may be flexibly manufactured in the form of a film using a polymer.
  • piezoelectric elements break more easily when stretched than when compressed.
  • the compressive allowable stress at which the breakage of the piezoelectric element can be prevented is greater than the tensile allowable stress. Accordingly, a piezoelectric energy harvester technology for preventing damage to the piezoelectric element by suppressing the tension of the piezoelectric element is being developed.
  • An object of the present invention is to provide a piezoelectric energy harvester with improved durability.
  • the substrate a piezoelectric element disposed on one surface or the other surface of the substrate; and an elastic body connecting the mounting surface on which the piezoelectric energy harvester is installed, and the free end of the substrate, and compressing the piezoelectric element.
  • a substrate having one end fixed to the wall surface; a piezoelectric element disposed on one surface of the substrate; and a bottom surface spaced apart from the substrate by a predetermined distance, and an elastic body connecting the free end of the substrate and compressing the piezoelectric element.
  • the piezoelectric element since the piezoelectric element is harvested in a compressed state, damage to the piezoelectric element due to tension can be reduced.
  • FIG. 1 is a view showing a general cantilever-type piezoelectric energy harvester.
  • FIG. 2 is a diagram showing the stress of the piezoelectric element.
  • 3 and 4 are diagrams for explaining a piezoelectric energy harvester according to an embodiment of the present invention.
  • FIG. 5 is a view showing the stress of a piezoelectric element according to an embodiment of the present invention.
  • FIG. 6 is a view for explaining a piezoelectric energy harvester according to another embodiment of the present invention.
  • FIG. 7 is a view for explaining a piezoelectric energy harvester according to another embodiment of the present invention.
  • FIG. 1 is a diagram illustrating a general cantilever type piezoelectric energy harvester
  • FIG. 2 is a diagram illustrating a stress of a piezoelectric element.
  • one end of the substrate 110 is fixed to the installation position 140 of the piezoelectric energy harvester, and the other end of the substrate 110 is opened.
  • the piezoelectric element 120 is disposed on one surface of the substrate 110 and between the fixed end that is one end of the substrate 110 and the free end that is the other end of the substrate, and a tip mass 130 is coupled to the free end.
  • the piezoelectric element 120 is also bent, and electric power is generated in the piezoelectric element 120 .
  • the piezoelectric element 120 When the elastic substrate 110 is bent in the direction 111 of one surface of the substrate, the piezoelectric element 120 is compressed, and when the substrate 110 is curved in the direction 112 of the other surface of the substrate, the piezoelectric element 120 ) is tensioned.
  • the compressive stress and tensile stress generated according to the compression and tension may occur as shown in the graph shown in FIG. 2 according to the passage of time t.
  • a direction that increases along the y-axis is a direction in which the compressive stress increases
  • a direction that decreases along the y-axis is a direction in which the tensile stress increases.
  • the tensile allowable stress 201 at which the piezoelectric element does not break is smaller than the compressive allowable stress 202, and therefore, the compressive stress of the piezoelectric element 120 as shown in FIG. 2(b) is the compressive allowable stress. Even if it does not exceed 202, the tensile stress will exceed the tensile allowable stress 201, and the piezoelectric element 120 may be broken.
  • the present invention proposes a piezoelectric energy harvester capable of providing the same effect as an increase in the allowable tensile stress of a piezoelectric element in order to prevent damage to the piezoelectric element due to tensile stress and improve durability of the piezoelectric element.
  • an embodiment of the present invention provides the same effect as an increase in tensile allowable stress by allowing the piezoelectric element of the piezoelectric energy harvester to harvest energy in a compressed state without limiting the tensile displacement of the piezoelectric element for this purpose. can do.
  • FIG. 3 and 4 are diagrams for explaining a piezoelectric energy harvester according to an embodiment of the present invention
  • FIG. 5 is a diagram illustrating a stress of a piezoelectric element according to an embodiment of the present invention.
  • a piezoelectric energy harvester includes a substrate 310 , a piezoelectric element 320 , and an elastic body 350 . And according to an embodiment, it may further include a tip mass coupled to the free end of the substrate 310 .
  • a piezoelectric element 320 is disposed on one surface 313 or the other surface 314 of the substrate 310 .
  • the elastic body 350 connects the installation surface 340 on which the piezoelectric energy harvester is installed and the free end of the substrate 310 , and compresses the piezoelectric element 320 .
  • the elastic body 350 may be fixed to the substrate 310 and the installation surface 340 in various ways to connect the installation surface 310 and the substrate 340 , and in one embodiment, the substrate 310 and the installation surface 340 . .
  • the elastic body 350 may be a spring or a cable made of an elastic material as an embodiment. And the length of the elastic body 350 is, in a state in which the elastic body 350 is not installed, the fixing point at which the elastic body 350 is fixed on the installation surface 340 and the fixing point at which the elastic body 350 is fixed on the substrate 310 . It may be shorter than the straight-line distance between points. Accordingly, the substrate 310 disposed perpendicular to the installation surface 340 is bent in the direction 311 of one surface of the substrate by the elastic body 350, and in this case, the piezoelectric element 320 disposed on one surface 313 of the substrate. can maintain a compressed state in a state where no external force is applied.
  • the piezoelectric element 320 Since the piezoelectric element 320 is maintained in a compressed state by the elastic body 350 , the piezoelectric element 350 may be compressed and stretched while the elastic body 350 is extended and contracted by an external force. In other words, as shown in FIG. 3 , the piezoelectric element 320 may be bent by an external force even in a compressed state. In this case, as shown in FIG. 5 , in a state in which the initial compressive stress 503 is generated in the piezoelectric element 320 , compressive stress and tensile stress are generated according to the bending of the piezoelectric element, so that the tensile strength by the initial compressive stress 503 is generated. An effect such as an increase in allowable stress can be exerted.
  • the tensile stress of the piezoelectric element 320 does not exceed the tensile allowable stress 201 as shown in FIG. 5, and thus the piezoelectric element 320 Damage to the element 320 can be prevented.
  • the elastic body 350 when the substrate 310 is fixed to be perpendicular to the installation surface 340 , the elastic body 350 includes the installation surface 340 and the substrate 310 perpendicular to the substrate. ) to connect the free ends.
  • the elastic body 350 when the fixed end of the substrate 310 is vertically fixed to a separate support 460 , and the support 460 is installed on the installation surface 440 parallel to the substrate 310 , the elastic body 350 may connect the installation surface 440 parallel to the substrate 310 and the free end of the substrate 310 .
  • the elastic body 350 is connected to the substrate 310 and the installation surface 440 such that the substrate 310 is bent in the direction 312 of the other surface of the substrate by the elastic body 350 .
  • the piezoelectric element 320 is disposed on the other surface 314 of the substrate, so that the compressed state can be maintained even in a state in which an external force is not applied.
  • FIG. 6 is a view for explaining a piezoelectric energy harvester according to another embodiment of the present invention.
  • one end of the substrate 310 is fixed to the wall surface 641, and the elastic body 350 is spaced apart from the substrate 310 by a predetermined distance from the bottom surface ( 642 and the free end of the substrate 310 are connected.
  • the bottom surface 642 may be perpendicular to the wall surface 641 and may have a horizontal relationship with the substrate 310 .
  • the piezoelectric element 320 is disposed on the other surface 314 of the substrate facing the bottom surface 642 , and the piezoelectric element 320 by the substrate 310 is bent in the direction 312 of the other surface of the substrate by the elastic body 350 . ) can be compressed.
  • FIG. 7 is a view for explaining a piezoelectric energy harvester according to another embodiment of the present invention.
  • the piezoelectric energy harvester may further include a length adjusting unit 770 for adjusting the length of the substrate, the piezoelectric element, and the elastic body as well as the elastic body 350 .
  • the initial compressive stress needs to be adjusted, and in one embodiment of the present invention, the length of the elastic body 350 is adjusted using the length adjusting unit 770 , thereby compressing the piezoelectric element. It is possible to control the degree and control the initial compressive stress generated in the piezoelectric element.
  • the piezoelectric energy harvester when used in an environment where the compressive and tensile stress of the piezoelectric element due to external force is very high, the probability that the piezoelectric element is damaged by the tensile stress is high, so by increasing the initial compressive stress by reducing the length of the elastic body It can reduce the possibility of breakage. Conversely, when the piezoelectric energy harvester is used in an environment where the compressive and tensile stress of the piezoelectric element due to external force is small, the probability that the piezoelectric element is damaged by the tensile stress is small. can increase
  • the elastic body 350 may connect the installation surface and the substrate 310 while being wound around the length adjusting unit 770 , and the length adjusting unit 770 may be coupled to a groove formed in the substrate 310 .
  • a screw thread may be formed in the length adjusting part 770 and the groove, and the length of the elastic body 350 may be extended or shortened according to the rotation direction of the length adjusting part 770 on which the elastic body 350 is wound.
  • the length adjusting unit 770 rotates in a clockwise direction, and as the rotational displacement increases, the length adjusting unit 770 is inserted in the direction of the substrate and the length of the elastic body 350 may be increased. Conversely, the length adjusting unit 770 rotates counterclockwise, and the rotational displacement may increase, and the length of the elastic body 350 may be shortened while the length of the length adjusting unit 770 protruding from the substrate 310 increases. .
  • an embodiment of the present invention limits the rotational displacement of the length adjusting unit 770 within a preset range. It may further include a limiter 780 .
  • the rotational displacement limiter 780 limits the extent to which the length adjusting part 770 protrudes by rotation, thereby preventing the length of the elastic body 350 from being too short.
  • the rotational displacement limiting unit 780 is installed at the free end of the substrate 310 on which the length adjusting unit 770 is installed, and may have a “L” shape.
  • the length adjusting unit 770 may be disposed on the installation surface according to an embodiment.

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  • General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)

Abstract

Disclosed is a piezoelectric energy harvester having improved durability. The disclosed piezoelectric energy harvester comprises: a substrate; a piezoelectric element disposed on one surface or the other surface of the substrate; and an elastic body connecting an installation surface on which the piezoelectric energy harvester is installed and a free end of the substrate, and compressing the piezoelectric element.

Description

내구성이 향상된 압전 에너지 하베스터Durable piezoelectric energy harvester
본 발명은 압전 에너지 하베스터에 관한 것으로서, 더욱 상세하게는 내구성이 향상된 압전 에너지 하베스터에 관한 것이다. The present invention relates to a piezoelectric energy harvester, and more particularly, to a piezoelectric energy harvester with improved durability.
근래에는 에너지 자원의 부족에 따라 다양한 에너지 생산 방법들이 연구되고 있는데, 특히, 최근에는 에너지 하베스팅(energy harvesting)이라는 개념으로 일상 생활에서 버려지는 에너지를 회수하는 시스템에 대한 연구가 활발히 진행되고 있다.Recently, various energy production methods are being studied according to the shortage of energy resources. In particular, recently, research on a system for recovering energy wasted in daily life under the concept of energy harvesting is being actively conducted.
에너지 하베스팅 기술은 진동, 빛, 열, 전자파 등 일상 생활에서 버려지는 에너지를 모아 사용 가능한 전기 에너지로 변환하는 기술을 의미하며, 매우 다양한 분야에서 활발한 연구가 진행되고 있다. Energy harvesting technology refers to a technology that collects energy wasted in daily life, such as vibration, light, heat, and electromagnetic waves, and converts it into usable electrical energy, and active research is being conducted in various fields.
이러한 에너지 하베스팅 기술의 한 종류로서, 압전 소자를 이용한 기술이 개발되고 있는데, 이는 반복적으로 전달되는 외부 압력을 전기 에너지로 변환하는 기술이다. 압전체는 기계적인 힘을 받았을 때 전기 에너지를 발생시키거나, 또는 전기적 에너지를 받았을 때 기계적인 변형을 일으킬 수 있는 물질로서, 수정, 세라믹(납-지르코니아-티타늄), AIN, LiNbO3, LiTaO3, ZnO, GaN 등과 같은 물질이 이용될 수 있다. 또한 압전체는, 폴리머를 이용하여 필름 형태로 유연하게 제조될 수도 있다.As a type of such energy harvesting technology, a technology using a piezoelectric element is being developed, which is a technology for converting repeatedly transmitted external pressure into electrical energy. A piezoelectric material is a material that generates electrical energy when subjected to mechanical force or can cause mechanical deformation when subjected to electrical energy. A material such as GaN may be used. In addition, the piezoelectric body may be flexibly manufactured in the form of a film using a polymer.
이러한 압전 소자는 압축되었을 때보다 인장되었을 때 보다 쉽게 파손된다. 다시 말해, 압전 소자의 파손이 방지될 수 있는 압축 허용 응력은 인장 허용 응력보다 크다. 따라서, 압전 소자의 인장을 억제하여 압전 소자의 파손을 방지하는 압전 에너지 하베스터 기술이 개발되고 있다.These piezoelectric elements break more easily when stretched than when compressed. In other words, the compressive allowable stress at which the breakage of the piezoelectric element can be prevented is greater than the tensile allowable stress. Accordingly, a piezoelectric energy harvester technology for preventing damage to the piezoelectric element by suppressing the tension of the piezoelectric element is being developed.
본 발명은 내구성이 향상된 압전 에너지 하베스터를 제공하기 위한 것이다.An object of the present invention is to provide a piezoelectric energy harvester with improved durability.
상기한 목적을 달성하기 위한 본 발명의 일 실시예에 따르면, 기판; 상기 기판의 일면 또는 타면에 배치되는 압전 소자; 및 압전 에너지 하베스터가 설치된 설치면과, 상기 기판의 자유단을 연결하며, 상기 압전 소자를 압축시키는 탄성체를 포함하는 압전 에너지 하베스터가 제공된다.According to an embodiment of the present invention for achieving the above object, the substrate; a piezoelectric element disposed on one surface or the other surface of the substrate; and an elastic body connecting the mounting surface on which the piezoelectric energy harvester is installed, and the free end of the substrate, and compressing the piezoelectric element.
또한 상기한 목적을 달성하기 위한 본 발명의 다른 실시예에 따르면, 벽면에 일단이 고정되는 기판; 상기 기판의 일면에 배치되는 압전 소자; 및 상기 기판으로부터 미리 설정된 거리만큼 이격된 바닥면과, 상기 기판의 자유단을 연결하며, 상기 압전 소자를 압축시키는 탄성체가 제공된다.In addition, according to another embodiment of the present invention for achieving the above object, a substrate having one end fixed to the wall surface; a piezoelectric element disposed on one surface of the substrate; and a bottom surface spaced apart from the substrate by a predetermined distance, and an elastic body connecting the free end of the substrate and compressing the piezoelectric element.
본 발명의 일실시예에 따르면, 압전 소자가 압축된 상태에서 하베스팅됨으로써, 인장에 따른 압전 소자의 파손이 줄어들 수 있다.According to an embodiment of the present invention, since the piezoelectric element is harvested in a compressed state, damage to the piezoelectric element due to tension can be reduced.
도 1은 일반적인 켄틸레버 타입의 압전 에너지 하베스터를 나타내는 도면이다. 1 is a view showing a general cantilever-type piezoelectric energy harvester.
도 2는 압전 소자의 응력을 나타내는 도면이다.2 is a diagram showing the stress of the piezoelectric element.
도 3 및 도 4는 본 발명의 일실시예에 따른 압전 에너지 하베스터를 설명하기 위한 도면이다. 3 and 4 are diagrams for explaining a piezoelectric energy harvester according to an embodiment of the present invention.
도 5는 본 발명의 일실시예에 따른 압전 소자의 응력을 나타내는 도면이다.5 is a view showing the stress of a piezoelectric element according to an embodiment of the present invention.
도 6은 본 발명의 다른 실시예에 따른 압전 에너지 하베스터를 설명하기 위한 도면이다.6 is a view for explaining a piezoelectric energy harvester according to another embodiment of the present invention.
도 7은 본 발명의 또 다른 실시예에 따른 압전 에너지 하베스터를 설명하기 위한 도면이다.7 is a view for explaining a piezoelectric energy harvester according to another embodiment of the present invention.
본 발명은 다양한 변경을 가할 수 있고 여러 가지 실시예를 가질 수 있는 바, 특정 실시예들을 도면에 예시하고 상세한 설명에 상세하게 설명하고자 한다. 그러나, 이는 본 발명을 특정한 실시 형태에 대해 한정하려는 것이 아니며, 본 발명의 사상 및 기술 범위에 포함되는 모든 변경, 균등물 내지 대체물을 포함하는 것으로 이해되어야 한다. 각 도면을 설명하면서 유사한 참조부호를 유사한 구성요소에 대해 사용하였다. Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing each figure, like reference numerals have been used for like elements.
도 1은 일반적인 켄틸레버 타입의 압전 에너지 하베스터를 나타내는 도면이며, 도 2는 압전 소자의 응력을 나타내는 도면이다.1 is a diagram illustrating a general cantilever type piezoelectric energy harvester, and FIG. 2 is a diagram illustrating a stress of a piezoelectric element.
도 1을 참조하면, 기판(110)의 일단이, 압전 에너지 하베스터의 설치 위치(140)에 고정되고, 기판(110)의 타단은 개방된다. 그리고 기판(110)의 일면에, 그리고 기판(110)의 일단인 고정단과 기판의 타단인 자유단 사이에 압전 소자(120)가 배치되며, 자유단에 팁매스(tip mass, 130)가 결합된다. 외부 진동 등에 의해 기판(110)이 휘어지면 압전 소자(120) 역시 휘어지면서, 압전 소자(120)에서 전력이 생성된다. Referring to FIG. 1 , one end of the substrate 110 is fixed to the installation position 140 of the piezoelectric energy harvester, and the other end of the substrate 110 is opened. And the piezoelectric element 120 is disposed on one surface of the substrate 110 and between the fixed end that is one end of the substrate 110 and the free end that is the other end of the substrate, and a tip mass 130 is coupled to the free end. . When the substrate 110 is bent by external vibration or the like, the piezoelectric element 120 is also bent, and electric power is generated in the piezoelectric element 120 .
탄성재질의 기판(110)이 기판의 일면 방향(111)으로 휘어질 경우, 압전 소자(120)가 압축되며, 기판(110)이 기판의 타면 방향(112)으로 휘어질 경우, 압전 소자(120)는 인장된다. 그리고 이러한 압축 및 인장에 따라 발생하는 압축 응력 및 인장 응력은 시간 흐름(t)에 따라 도 2에 도시된 그래프와 같이, 발생할 수 있다. 도 2에서 y축으로 증가하는 방향은 압축 응력이 증가하는 방향이며, y축으로 감소하는 방향은 인장 응력이 증가하는 방향이다. When the elastic substrate 110 is bent in the direction 111 of one surface of the substrate, the piezoelectric element 120 is compressed, and when the substrate 110 is curved in the direction 112 of the other surface of the substrate, the piezoelectric element 120 ) is tensioned. In addition, the compressive stress and tensile stress generated according to the compression and tension may occur as shown in the graph shown in FIG. 2 according to the passage of time t. In FIG. 2 , a direction that increases along the y-axis is a direction in which the compressive stress increases, and a direction that decreases along the y-axis is a direction in which the tensile stress increases.
기판(110) 및 압전 소자(120)가 휘어지는 정도가 커질수록, 압전 소자(120)에서 발생하는 압축 응력 및 인장 응력은 증가한다. 도 2(a)와 같이 압전 소자(120)에 응력이 발생하는 상태에서, 압전 소자(120)가 더욱 휘어지면, 도 2(b)와 같이 응력이 발생할 수 있다.As the degree of bending of the substrate 110 and the piezoelectric element 120 increases, the compressive stress and tensile stress generated in the piezoelectric element 120 increase. When the piezoelectric element 120 is further bent in a state in which stress is generated in the piezoelectric element 120 as shown in FIG. 2( a ), stress may be generated as shown in FIG. 2( b ).
압전 소자의 재료 특성상, 압전 소자가 파손되지 않는 인장 허용 응력(201)은 압축 허용 응력(202)보다 작으며, 따라서, 도 2(b)와 같이 압전 소자(120)의 압축 응력은 압축 허용 응력(202)을 초과하지 않더라도, 인장 응력이 인장 허용 응력(201)을 초과하게 되어, 압전 소자(120)가 파손될 수 있다. Due to the material properties of the piezoelectric element, the tensile allowable stress 201 at which the piezoelectric element does not break is smaller than the compressive allowable stress 202, and therefore, the compressive stress of the piezoelectric element 120 as shown in FIG. 2(b) is the compressive allowable stress. Even if it does not exceed 202, the tensile stress will exceed the tensile allowable stress 201, and the piezoelectric element 120 may be broken.
본 발명은 인장 응력에 의한 압전 소자의 파손을 방지하고 압전 소자의 내구성을 향상시키기 위해, 압전 소자의 인장 허용 응력이 증가된 것과 동일한 효과를 제공할 수 있는 압전 에너지 하베스터를 제안한다.The present invention proposes a piezoelectric energy harvester capable of providing the same effect as an increase in the allowable tensile stress of a piezoelectric element in order to prevent damage to the piezoelectric element due to tensile stress and improve durability of the piezoelectric element.
그리고 본 발명의 일실시예는 이를 위해 압전 소자의 인장 변위를 제한함이 없이, 압전 에너지 하베스터의 압전 소자가 압축된 상태에서 에너지를 하베스팅하도록 함으로써, 인장 허용 응력이 증가된 것과 동일한 효과를 제공할 수 있다.In addition, an embodiment of the present invention provides the same effect as an increase in tensile allowable stress by allowing the piezoelectric element of the piezoelectric energy harvester to harvest energy in a compressed state without limiting the tensile displacement of the piezoelectric element for this purpose. can do.
이하에서, 본 발명에 따른 실시예들을 첨부된 도면을 참조하여 상세하게 설명한다.Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.
도 3 및 도 4는 본 발명의 일실시예에 따른 압전 에너지 하베스터를 설명하기 위한 도면이며, 도 5는 본 발명의 일실시예에 따른 압전 소자의 응력을 나타내는 도면이다.3 and 4 are diagrams for explaining a piezoelectric energy harvester according to an embodiment of the present invention, and FIG. 5 is a diagram illustrating a stress of a piezoelectric element according to an embodiment of the present invention.
도 3을 참조하면, 본 발명의 일실시예에 따른 압전 에너지 하베스터는 기판(310), 압전 소자(320) 및 탄성체(350)를 포함한다. 그리고 실시예에 따라서, 기판(310)의 자유단에 결합되는 팁매스를 더 포함할 수 있다.Referring to FIG. 3 , a piezoelectric energy harvester according to an embodiment of the present invention includes a substrate 310 , a piezoelectric element 320 , and an elastic body 350 . And according to an embodiment, it may further include a tip mass coupled to the free end of the substrate 310 .
기판(310)의 일면(313) 또는 타면(314)에 압전 소자(320)가 배치된다. A piezoelectric element 320 is disposed on one surface 313 or the other surface 314 of the substrate 310 .
탄성체(350)는 압전 에너지 하베스터가 설치된 설치면(340)과, 기판(310)의 자유단을 연결하며, 압전 소자(320)를 압축시킨다. 탄성체(350)는 다양한 방식으로 기판(310) 및 설치면(340)에 고정되어, 설치면(310)과 기판(340)을 연결할 수 있으며, 일실시예로서 기판(310) 및 설치면(340)에 형성된 홈에 삽입되어 고정되거나, 기판(310) 및 설치면(340)에 돌출된 돌출부에 감겨진 상태로 고정될 수 있다. The elastic body 350 connects the installation surface 340 on which the piezoelectric energy harvester is installed and the free end of the substrate 310 , and compresses the piezoelectric element 320 . The elastic body 350 may be fixed to the substrate 310 and the installation surface 340 in various ways to connect the installation surface 310 and the substrate 340 , and in one embodiment, the substrate 310 and the installation surface 340 . .
탄성체(350)는 일실시예로서 용수철이나 탄성 재질의 케이블일 수 있다. 그리고 탄성체(350)의 길이는, 탄성체(350)가 설치되지 않은 상태에서의, 설치면(340)에서 탄성체(350)가 고정되는 고정 지점과 기판(310)에서 탄성체(350)가 고정되는 고정 지점 사이의 직선 거리보다 짧을 수 있다. 따라서, 설치면(340)과 수직으로 배치된 기판(310)은 탄성체(350)에 의해 기판의 일면 방향(311)으로 휘어지며, 이 경우 기판의 일면(313)에 배치된 압전 소자(320)는 외력이 인가되지 않는 상태에서 압축 상태를 유지할 수 있다.The elastic body 350 may be a spring or a cable made of an elastic material as an embodiment. And the length of the elastic body 350 is, in a state in which the elastic body 350 is not installed, the fixing point at which the elastic body 350 is fixed on the installation surface 340 and the fixing point at which the elastic body 350 is fixed on the substrate 310 . It may be shorter than the straight-line distance between points. Accordingly, the substrate 310 disposed perpendicular to the installation surface 340 is bent in the direction 311 of one surface of the substrate by the elastic body 350, and in this case, the piezoelectric element 320 disposed on one surface 313 of the substrate. can maintain a compressed state in a state where no external force is applied.
압전 소자(320)는 탄성체(350)에 의해 압축 상태를 유지하는 것이므로, 외력에 의해 탄성체(350)가 연장 및 수축되면서 압전 소자(350)는 압축 및 인장될 수 있다. 다시 말해, 압전 소자(320)는 도 3과 같이, 압축 상태를 유지한 상태에서도 외력에 의해 휘어질 수 있다. 이 경우, 도 5에 도시된 같이, 압전 소자(320)에 초기 압축 응력(503)이 발생한 상태에서, 압전 소자가 휘어짐에 따른 압축 응력 및 인장 응력이 발생하므로, 초기 압축 응력(503)만큼 인장 허용 응력이 증가된 것과 같은 효과가 발휘될 수 있다. 따라서, 도 2(b)와 같은 압축 응력 및 인장 응력이 발생하는 환경에서, 압전 소자(320)의 인장 응력은 도 5에 도시된 바와 같이, 인장 허용 응력(201)을 초과하지 않으며, 따라서 압전 소자(320)의 파손이 방지될 수 있다. Since the piezoelectric element 320 is maintained in a compressed state by the elastic body 350 , the piezoelectric element 350 may be compressed and stretched while the elastic body 350 is extended and contracted by an external force. In other words, as shown in FIG. 3 , the piezoelectric element 320 may be bent by an external force even in a compressed state. In this case, as shown in FIG. 5 , in a state in which the initial compressive stress 503 is generated in the piezoelectric element 320 , compressive stress and tensile stress are generated according to the bending of the piezoelectric element, so that the tensile strength by the initial compressive stress 503 is generated. An effect such as an increase in allowable stress can be exerted. Therefore, in an environment in which compressive stress and tensile stress as shown in FIG. 2(b) occur, the tensile stress of the piezoelectric element 320 does not exceed the tensile allowable stress 201 as shown in FIG. 5, and thus the piezoelectric element 320 Damage to the element 320 can be prevented.
다시 도 3으로 돌아가, 도 3에 도시된 바와 같이, 기판(310)이 설치면(340)과 수직이 되도록 고정된 경우, 탄성체(350)는 기판과 수직한 설치면(340)과 기판(310)의 자유단을 연결한다. 또는 도 4에 도시된 바와 같이, 기판(310)의 고정단이 별도의 지지부(460)에 수직으로 고정되고, 지지부(460)가 기판(310)과 평행한 설치면(440)에 설치될 경우, 탄성체(350)는 기판(310)과 평행한 설치면(440)과, 기판(310)의 자유단을 연결할 수 있다.Returning to FIG. 3 again, as shown in FIG. 3 , when the substrate 310 is fixed to be perpendicular to the installation surface 340 , the elastic body 350 includes the installation surface 340 and the substrate 310 perpendicular to the substrate. ) to connect the free ends. Alternatively, as shown in FIG. 4 , when the fixed end of the substrate 310 is vertically fixed to a separate support 460 , and the support 460 is installed on the installation surface 440 parallel to the substrate 310 , , the elastic body 350 may connect the installation surface 440 parallel to the substrate 310 and the free end of the substrate 310 .
만일, 도 4에 도시된 바와 같이, 기판(310)이 탄성체(350)에 의해 기판의 타면 방향(312)으로 휘어지도록, 탄성체(350)가 기판(310) 및 설치면(440)에 연결된 경우, 압전 소자(320)는 기판의 타면(314)에 배치됨으로써, 외력이 인가되지 않는 상태에서도 압축 상태를 유지할 수 있다.If, as shown in FIG. 4 , the elastic body 350 is connected to the substrate 310 and the installation surface 440 such that the substrate 310 is bent in the direction 312 of the other surface of the substrate by the elastic body 350 . , the piezoelectric element 320 is disposed on the other surface 314 of the substrate, so that the compressed state can be maintained even in a state in which an external force is not applied.
도 6은 본 발명의 다른 실시예에 따른 압전 에너지 하베스터를 설명하기 위한 도면이다.6 is a view for explaining a piezoelectric energy harvester according to another embodiment of the present invention.
전술된 실시예와 달리, 도 6에 도시된 실시예에서, 기판(310)의 일단은 벽면(641)에 고정되며, 탄성체(350)는 기판(310)으로부터 미리 설정된 거리만큼 이격된 바닥면(642)과, 기판(310)의 자유단을 연결한다. 바닥면(642)은 벽면(641)과 수직하며 기판(310)과는 수평한 관계일 수 있다.Unlike the above-described embodiment, in the embodiment shown in Fig. 6, one end of the substrate 310 is fixed to the wall surface 641, and the elastic body 350 is spaced apart from the substrate 310 by a predetermined distance from the bottom surface ( 642 and the free end of the substrate 310 are connected. The bottom surface 642 may be perpendicular to the wall surface 641 and may have a horizontal relationship with the substrate 310 .
압전 소자(320)는 바닥면(642)과 마주보는 기판의 타면(314)에 배치되며, 탄성체(350)에 의해, 기판의 타면 방향(312)으로 휘어지는 기판(310)에 의해 압전 소자(320)는 압축될 수 있다.The piezoelectric element 320 is disposed on the other surface 314 of the substrate facing the bottom surface 642 , and the piezoelectric element 320 by the substrate 310 is bent in the direction 312 of the other surface of the substrate by the elastic body 350 . ) can be compressed.
도 7은 본 발명의 또 다른 실시예에 따른 압전 에너지 하베스터를 설명하기 위한 도면이다.7 is a view for explaining a piezoelectric energy harvester according to another embodiment of the present invention.
본 발명의 일실시예에 따른 압전 에너지 하베스터는 기판, 압전 소자, 탄성체 뿐만 아니라 탄성체(350)의 길이를 조절하는 길이 조절부(770)를 더 포함할 수 있다. The piezoelectric energy harvester according to an embodiment of the present invention may further include a length adjusting unit 770 for adjusting the length of the substrate, the piezoelectric element, and the elastic body as well as the elastic body 350 .
압전 에너지 하베스터가 사용되는 환경에 따라서, 초기 압축 응력이 조절될 필요가 있으며, 본 발명의 일실시예는 길이 조절부(770)를 이용하여 탄성체(350)의 길이를 조절함으로써, 압전 소자의 압축 정도를 조절하고, 압전 소자에서 발생하는 초기 압축 응력을 조절할 수 있다. Depending on the environment in which the piezoelectric energy harvester is used, the initial compressive stress needs to be adjusted, and in one embodiment of the present invention, the length of the elastic body 350 is adjusted using the length adjusting unit 770 , thereby compressing the piezoelectric element. It is possible to control the degree and control the initial compressive stress generated in the piezoelectric element.
예컨대, 외력에 의한 압전 소자의 압축 및 인장 응력이 매우 큰 환경에서 압전 에너지 하베스터가 사용되는 경우에는 인장 응력에 의해 압전 소자가 파손된 가능성이 높으므로, 탄성체의 길이를 줄여 초기 압축 응력을 증가시킴으로써 파손 가능성을 줄일 수 있다. 반대로 외력에 의한 압전 소자의 압축 및 인장 응력이 작은 환경에서 압전 에너지 하베스터가 사용되는 경우에는 인장 응력에 의해 압전 소자가 파손된 가능성이 적으므로, 탄성체의 길이를 늘려 초기 압축 응력을 감소시킴으로써 발전 효율을 높일 수 있다.For example, when the piezoelectric energy harvester is used in an environment where the compressive and tensile stress of the piezoelectric element due to external force is very high, the probability that the piezoelectric element is damaged by the tensile stress is high, so by increasing the initial compressive stress by reducing the length of the elastic body It can reduce the possibility of breakage. Conversely, when the piezoelectric energy harvester is used in an environment where the compressive and tensile stress of the piezoelectric element due to external force is small, the probability that the piezoelectric element is damaged by the tensile stress is small. can increase
탄성체(350)는 길이 조절부(770)에 감겨진 상태로 설치면과 기판(310)을 연결할 수 있으며, 길이 조절부(770)는 기판(310)에 형성된 홈에 결합될 수 있다. 길이 조절부(770)와 홈에는 나사산이 형성될 수 있으며, 탄성체(350)가 감겨진 길이 조절부(770)의 회전 방향에 따라서 탄성체(350)의 길이는 연장 또는 단축될 수 있다. The elastic body 350 may connect the installation surface and the substrate 310 while being wound around the length adjusting unit 770 , and the length adjusting unit 770 may be coupled to a groove formed in the substrate 310 . A screw thread may be formed in the length adjusting part 770 and the groove, and the length of the elastic body 350 may be extended or shortened according to the rotation direction of the length adjusting part 770 on which the elastic body 350 is wound.
일실시예로서, 길이 조절부(770)가 시계 방향으로 회전하며, 회전 변위가 증가할수록, 길이 조절부(770)는 기판 방향으로 삽입되고 탄성체(350)의 길이는 길어질 수 있다. 반대로 길이 조절부(770)가 반시계 방향으로 회전하며, 회전 변위가 증가할수, 길이 조절부(770)의 기판(310)으로부터의 돌출 길이가 증가하면서 탄성체(350)의 길이는 짧아질 수 있다.As an embodiment, the length adjusting unit 770 rotates in a clockwise direction, and as the rotational displacement increases, the length adjusting unit 770 is inserted in the direction of the substrate and the length of the elastic body 350 may be increased. Conversely, the length adjusting unit 770 rotates counterclockwise, and the rotational displacement may increase, and the length of the elastic body 350 may be shortened while the length of the length adjusting unit 770 protruding from the substrate 310 increases. .
한편, 탄성체의 길이가 지나치게 짧아질 경우, 탄성체의 탄성력이 상실될 수 있으므로 이를 방지하기 위해, 본 발명의 일실시예는 길이 조절부(770)의 회전 변위를 미리 설정된 범위 내에서 제한하는 회전 변위 제한부(780)를 더 포함할 수 있다. 회전 변위 제한부(780)는 길이 조절부(770)가 회전에 의해 돌출되는 정도를 제한하여, 탄성체(350)의 길이가 지나치게 짧아지는 것을 방지한다. 회전 변위 제한부(780)는 일실시예로서, 길이 조절부(770)가 설치된 기판(310)의 자유단에 설치되며 "ㄱ" 형상일 수 있다.On the other hand, when the length of the elastic body is too short, the elastic force of the elastic body may be lost. In order to prevent this, an embodiment of the present invention limits the rotational displacement of the length adjusting unit 770 within a preset range. It may further include a limiter 780 . The rotational displacement limiter 780 limits the extent to which the length adjusting part 770 protrudes by rotation, thereby preventing the length of the elastic body 350 from being too short. The rotational displacement limiting unit 780 is installed at the free end of the substrate 310 on which the length adjusting unit 770 is installed, and may have a “L” shape.
도 7에는 길이 조절부(770)가 기판(310)에 설치된 실시예가 도시되어 있으나, 실시예에 따라서 길이 조절부(770)는 설치면에 배치될 수도 있다.7 illustrates an embodiment in which the length adjusting unit 770 is installed on the substrate 310, the length adjusting unit 770 may be disposed on the installation surface according to an embodiment.
이상과 같이 본 발명에서는 구체적인 구성 요소 등과 같은 특정 사항들과 한정된 실시예 및 도면에 의해 설명되었으나 이는 본 발명의 보다 전반적인 이해를 돕기 위해서 제공된 것일 뿐, 본 발명은 상기의 실시예에 한정되는 것은 아니며, 본 발명이 속하는 분야에서 통상적인 지식을 가진 자라면 이러한 기재로부터 다양한 수정 및 변형이 가능하다. 따라서, 본 발명의 사상은 설명된 실시예에 국한되어 정해져서는 아니되며, 후술하는 특허청구범위뿐 아니라 이 특허청구범위와 균등하거나 등가적 변형이 있는 모든 것들은 본 발명 사상의 범주에 속한다고 할 것이다.As described above, the present invention has been described with specific matters such as specific components and limited embodiments and drawings, but these are provided to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments. , various modifications and variations are possible from these descriptions by those of ordinary skill in the art to which the present invention pertains. Therefore, the spirit of the present invention should not be limited to the described embodiments, and not only the claims to be described later, but also all those with equivalent or equivalent modifications to the claims will be said to belong to the scope of the spirit of the present invention. .

Claims (10)

  1. 압전 에너지 하베스터에 있어서,In the piezoelectric energy harvester,
    기판;Board;
    상기 기판의 일면 또는 타면에 배치되는 압전 소자; 및a piezoelectric element disposed on one surface or the other surface of the substrate; and
    상기 압전 에너지 하베스터가 설치된 설치면과, 상기 기판의 자유단을 연결하며, 상기 압전 소자를 압축시키는 탄성체An elastic body connecting the installation surface on which the piezoelectric energy harvester is installed and the free end of the substrate, and compressing the piezoelectric element
    를 포함하는 압전 에너지 하베스터.A piezoelectric energy harvester comprising a.
  2. 제 1항에 있어서,The method of claim 1,
    상기 압전 소자는 The piezoelectric element is
    상기 기판이 상기 탄성체에 의해 상기 기판의 일면 방향으로 휘어지는 경우, 상기 일면에 배치되며, When the substrate is bent in the direction of one surface of the substrate by the elastic body, it is disposed on the one surface,
    상기 기판이 상기 탄성체에 의해 상기 기판의 타면 방향으로 휘어지는 경우, 상기 타면에 배치되는When the substrate is bent in the direction of the other surface of the substrate by the elastic body, it is disposed on the other surface
    압전 에너지 하베스터.Piezoelectric energy harvester.
  3. 제 2항에 있어서,3. The method of claim 2,
    상기 탄성체는The elastic body
    상기 기판과 수직한 설치면과, 상기 자유단을 연결하는Connecting the installation surface perpendicular to the substrate and the free end
    압전 에너지 하베스터.Piezoelectric energy harvester.
  4. 제 2항에 있어서,3. The method of claim 2,
    상기 기판과 평행한 설치면과, 상기 자유단을 연결하는Connecting the installation surface parallel to the substrate and the free end
    압전 에너지 하베스터.Piezoelectric energy harvester.
  5. 제 1항에 있어서,The method of claim 1,
    상기 탄성체의 길이를 조절하는 길이 조절부Length adjusting unit for adjusting the length of the elastic body
    를 더 포함하는 압전 에너지 하베스터.A piezoelectric energy harvester further comprising a.
  6. 제 5항에 있어서,6. The method of claim 5,
    상기 탄성체의 길이는The length of the elastic body is
    상기 탄성체가 감겨진 상기 길이 조절부의 회전 방향에 따라서 연장 또는 단축되는Extending or shortening according to the rotation direction of the length adjustment part on which the elastic body is wound
    압전 에너지 하베스터.Piezoelectric energy harvester.
  7. 제 6항에 있어서,7. The method of claim 6,
    상기 길이 조절부의 회전 변위를 미리 설정된 범위 내에서 제한하는 회전 변위 제한부Rotational displacement limiting part for limiting the rotational displacement of the length adjusting part within a preset range
    를 더 포함하는 압전 에너지 하베스터.A piezoelectric energy harvester further comprising a.
  8. 압전 에너지 하베스터에 있어서,In the piezoelectric energy harvester,
    벽면에 일단이 고정되는 기판;a substrate having one end fixed to the wall;
    상기 기판의 일면에 배치되는 압전 소자; 및a piezoelectric element disposed on one surface of the substrate; and
    상기 기판으로부터 미리 설정된 거리만큼 이격된 바닥면과, 상기 기판의 자유단을 연결하며, 상기 압전 소자를 압축시키는 탄성체An elastic body that connects a bottom surface spaced apart from the substrate by a predetermined distance and a free end of the substrate and compresses the piezoelectric element
    를 포함하는 압전 에너지 하베스터.A piezoelectric energy harvester comprising a.
  9. 제 8항에 있어서,9. The method of claim 8,
    상기 기판은the substrate is
    상기 탄성체에 의해, 상기 기판의 일면 방향으로 휘어지는By the elastic body, bent in the direction of one surface of the substrate
    압전 에너지 하베스터.Piezoelectric energy harvester.
  10. 제 8항에 있어서,9. The method of claim 8,
    상기 탄성체의 길이를 조절하는 길이 조절부Length adjusting unit for adjusting the length of the elastic body
    를 더 포함하는 압전 에너지 하베스터.A piezoelectric energy harvester further comprising a.
PCT/KR2020/016317 2020-04-29 2020-11-19 Piezoelectric energy harvester having improved durability WO2021221253A1 (en)

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KR1020200052420A KR20210133606A (en) 2020-04-29 2020-04-29 Piezoelectric energy harvester with improved durability

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JP2005312269A (en) * 2004-04-26 2005-11-04 Nec Corp Power generation method by vibration, vibration generator, and vibration generation device
US20100141096A1 (en) * 2005-11-23 2010-06-10 Churchill David L Piezoelectric Composite Beam with Automatically Adjustable Natural Frequency
KR101380559B1 (en) * 2012-07-31 2014-04-01 주식회사 에이엠씨에너지 Piezoelectric harvesting system for using compressive force
KR20150059513A (en) * 2013-11-22 2015-06-01 한국기계연구원 2 degree of freedom piezoelectric energy harvester
KR101830385B1 (en) * 2016-10-13 2018-02-21 한양대학교 산학협력단 Broadband piezoelectric energy harvester

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005312269A (en) * 2004-04-26 2005-11-04 Nec Corp Power generation method by vibration, vibration generator, and vibration generation device
US20100141096A1 (en) * 2005-11-23 2010-06-10 Churchill David L Piezoelectric Composite Beam with Automatically Adjustable Natural Frequency
KR101380559B1 (en) * 2012-07-31 2014-04-01 주식회사 에이엠씨에너지 Piezoelectric harvesting system for using compressive force
KR20150059513A (en) * 2013-11-22 2015-06-01 한국기계연구원 2 degree of freedom piezoelectric energy harvester
KR101830385B1 (en) * 2016-10-13 2018-02-21 한양대학교 산학협력단 Broadband piezoelectric energy harvester

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