Wave power generation device

Abstract

This enables higher output power in wave power generation devices that utilize the piezoelectric effect. [Solution] The wave power generation device 10 comprises a plurality of base materials 11 whose main surface direction intersects with the arrangement direction of the left and right floating bodies 51 and which are arranged at predetermined intervals along the arrangement direction, and a coupling portion that alternately positions at the first end 111 and the second end 112 of the base material 11 in the order along the arrangement direction, a first piezoelectric layer 131 provided adjacent to one main surface of the base material 11, a first electrode 141 provided on one main surface of the first piezoelectric layer 131, and a second electrode 142 provided on the main surface of the first piezoelectric layer 131 opposite to the main surface on which the first electrode 141 is provided.

Description

Technical Field

[0001] The present invention relates to a wave power generation device.

Background Art

[0002] Conventionally, devices for converting wave energy into electrical energy in wave power generation include hydraulic, direct drive, mechanical, pneumatic types, etc. In contrast, in recent years, research on wave power generation devices using the piezoelectric effect, which have a simple structure and are easy to maintain, has been underway. For example, Patent Document 1 discloses the structure of a wave power generation device using the piezoelectric effect.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above structure, the number of piezoelectric layers is relatively small, and there is a risk that it is difficult to increase the output power. The present invention is a wave power generation device using the piezoelectric effect, and an object thereof is to provide a wave power generation device capable of increasing the output power.

Means for Solving the Problems

[0005] The present invention relates to a wave power generation device that connects a first object and a second object, deforms due to the wave force motion of at least one of the first object and the second object, and generates electricity, comprising a plurality of plate-shaped base materials whose main surface direction intersects the arrangement direction of the first object and the second object, and which are arranged at predetermined intervals along the arrangement direction, and the first object and the base material closest to the first object, adjacent base materials to each other, and the second object and the base material closest to the second object, respectively, and the arrangement The wave power generation device comprises: a coupling portion alternately located at a first end of the substrate and at a second end opposite to the first end, in order along the column direction; a first piezoelectric layer provided adjacent to one main surface of the substrate; a first electrode provided on at least a portion of one main surface of the first piezoelectric layer; and a second electrode provided on at least a portion of the main surface of the first piezoelectric layer opposite to the main surface on which the first electrode is provided, at a position facing the first electrode across the first piezoelectric layer. [Effects of the Invention]

[0006] According to an aspect of the present invention, it becomes possible to increase the output power of a wave power generation device that utilizes the piezoelectric effect. [Brief explanation of the drawing]

[0007] [Figure 1] This is a front view showing the structure of a wave power generation system. [Figure 2] This is a top view showing the structure of a wave power generation system. [Figure 3] This is a front view (cross-sectional view) showing the structure of the wave power generation device of this embodiment when it is in a stationary position. [Figure 4] This is a top view (cross-sectional view) showing the structure of the wave power generation device of this embodiment when it is in a stationary position. [Figure 5] This is a front view (cross-sectional view) showing the deformation state of the wave power generation device of this embodiment during power generation. [Figure 6] This is a front view (cross-sectional view) showing the deformation state of the wave power generation device of this embodiment during power generation. [Figure 7]This is a front view (cross-sectional view) showing the deformation state around the base material of the wave power generation device of this embodiment during power generation. [Figure 8] This is a front view (cross-sectional view) showing the deformation state around the base material of the wave power generation device of this embodiment during power generation. [Figure 9] This is a front view showing the structure of a wave power generation system. [Figure 10] This is a top view showing the structure of a wave power generation system. [Modes for carrying out the invention]

[0008] Hereinafter, an embodiment of the wave power generation apparatus of the present invention will be described with reference to Figures 1 to 8.

[0009] Figure 1 is a front view showing the structure of the wave power generation system 50. Figure 2 is a top view showing the structure of the wave power generation system 50.

[0010] As shown in Figures 1 and 2, the wave power generation system 50 is equipped with a floating body 51, a wave power generation device 10, and wiring cables 52, and has a structure that floats on the water surface 81. As shown in Figure 2, four floating bodies 51 are arranged in a straight line, and the wave power generation device 10 connects adjacent floating bodies 51. In addition, the wave power generation device 10 connects adjacent floating bodies 51 at two positions separated in a direction intersecting the direction in which the floating bodies 51 are connected. When each wave power generation device 10 is used as a reference, the floating body 51 on the left corresponds to the first object, and the floating body 51 on the right corresponds to the second object.

[0011] As shown in Figure 1, when waves or other disturbances occur on the water surface 81, a change in the vertical Z position occurs on the water surface 81. This results in a difference in the vertical Z position between each of the floating bodies 51, causing each floating body 51 to tilt and the wave power generation device 10 to deform.

[0012] FIG. 3 is a front view showing the structure of the wave power generation device 10 of the present embodiment when it is stationary, and is a cross-sectional view taken along the cross-section B-B in FIG. 2. Further, FIG. 4 is a top view showing the structure of the wave power generation device 10 of the present embodiment when it is stationary, and is a cross-sectional view taken along the cross-section A-A in FIG. 1. FIGS. 3 to 4 are views of a state in which the wave power generation system 50 is stationary and the wave power generation device 10 is not deformed.

[0013] As shown in FIGS. 3 to 4, with the wave power generation device 10 as a reference, the left floating body 51 (first object) and the right floating body 51 (second object) are arranged along the direction X. The wave power generation device 10 connects the left floating body 51 (first object) and the right floating body 51 (second object). The wave power generation device 10 includes a base material 11, a coupling part 12, a first piezoelectric layer 131, a first electrode 141, a second electrode 142, a second piezoelectric layer 132, a third electrode 143, a fourth electrode 144, and the like.

[0014] The base material 11 is a plate-shaped member made of a metal material such as carbon steel, alloy steel, aluminum alloy, titanium alloy, nickel alloy, a resin material such as polycarbonate, polyethylene terephthalate, a composite material such as fiber-reinforced resin, and the like. The wave power generation device 10 includes six base materials 11. The base materials 11 are arranged such that the main surface direction is perpendicular to the direction X. Further, the base materials 11 are arranged at a predetermined interval along the direction X. The number of the base materials 11 is not limited to six, and may be a plurality. Also, the main surface direction of the base material 11 is not limited to the direction perpendicular to the direction X, and may be any direction intersecting the direction X.

[0015] The coupling part 12 is a member made of a metal material such as carbon steel, alloy steel, aluminum alloy, titanium alloy, nickel alloy, a resin material such as polycarbonate, polyethylene terephthalate, a composite material such as fiber-reinforced resin, and the like. The wave power generation device 10 includes seven connecting parts 12. The connecting parts 12 connect the left floating body 51 (the first object) and the base material 11 closest to the left floating body 51 (the first object), adjacent base materials 11 to each other, and the right floating body 51 (the second object) and the base material 11 closest to the right floating body 51 (the second object), respectively. Further, the connecting parts 12 are alternately located at the first end 111 of the base material 11 and the second end 112 located on the side opposite to the first end 111 in the order along the direction X. Thereby, the structure combining the base material 11 and the connecting parts 12 becomes a zigzag structure along the direction X. The first end 111 may be located above or below the second end 112 along the vertical direction Z as shown in FIG. 3. The number of the connecting parts 12 is not limited to seven, and may be three or more.

[0016] Two first piezoelectric layers 131 are provided at positions adjacent to one main surface of the base material 11. The first electrodes 141 are provided on at least a part of the surface between the first piezoelectric layer 131 and the base material 11 and at least a part of the main surface of the first piezoelectric layer 131 farthest from the base material 11. Also, the second electrodes 142 are provided on at least a part of the surface between the two first piezoelectric layers 131, which is the main surface opposite to the main surface on which the first electrodes 141 of the first piezoelectric layer 131 are provided, and at a position facing the first electrodes 141 with the first piezoelectric layer 131 interposed therebetween. In this configuration, two first electrodes 141 and one second electrode 142 are provided. The number of the first piezoelectric layers 131 is not limited to two, and may be one or a plurality.

[0017] Two second piezoelectric layers 132 are provided on the substrate 11 at positions adjacent to the main surface opposite to the main surface adjacent to the first piezoelectric layer 131. A third electrode 143 is provided on at least a portion of the surface between the second piezoelectric layers 132 and the substrate 11, and on at least a portion of the main surface of the second piezoelectric layers 132 furthest from the substrate 11. A fourth electrode 144 is provided on at least a portion of the surface between the two second piezoelectric layers 132, which is the main surface of the second piezoelectric layers 132 opposite to the main surface where the third electrode 143 is provided, at a position facing the third electrode 143 across the second piezoelectric layers 132. In this configuration, two third electrodes 143 and one fourth electrode 144 are provided. The number of second piezoelectric layers 132 is not limited to two; it may be one or multiple.

[0018] The first piezoelectric layer 131 and the second piezoelectric layer 132 are made of piezoelectric ceramic materials such as lead zirconate titanate (PZT) and barium titanate (BaTiO3), piezoelectric resin materials such as polyvinylidene fluoride (PVDF), polylactic acid (PLA), and porous polypropylene. The first piezoelectric layer 131 and the second piezoelectric layer 132 may be made using sheet-shaped components of the material, or they may be formed by depositing the material onto the surface of the electrode, etc., using methods such as aerosol deposition (AD) or chemical solution deposition (CSD).

[0019] The first electrode 141, the second electrode 142, the third electrode 143, and the fourth electrode 144 are made of a material containing a conductive material such as copper, silver, nickel, gold, or carbon. The first electrode 141, the second electrode 142, the third electrode 143, and the fourth electrode 144 may be formed by applying a paste containing the conductive material, or by ejecting an ink containing the conductive material by an inkjet method. Alternatively, the electrodes may be formed by depositing the conductive material onto the surface of the piezoelectric layer by vapor deposition, sputtering, or the like.

[0020] The wave power generation device 10 may be equipped with a deformation restricting section 16. The deformation restricting section 16 may be located near the end of the main surface of the base material 11 where the joint section 12 is located, on the side opposite to the end where the joint section 12 is located. That is, if the joint section 12 is located at the first end 111, the deformation restricting section 16 may be located near the second end 112, and if the joint section 12 is located at the second end 112, the deformation restricting section 16 may be located near the first end 111. The deformation restricting portion 16 has a shape that protrudes from the main surface of the base material 11. As shown in Figure 3, the distance H between the vertex of the deformation restricting portion 16 and the base material 11 is greater than the distance G between the first electrode 141, which is furthest from the base material 11, and the base material 11.

[0021] The wave power generation device 10 may be equipped with a cover 17 at its outermost position. The cover 17 is a deformable member with a shape such as a bellows, and covers the base material 11, the joint 12, the first piezoelectric layer 131, the first electrode 141, the second electrode 142, the second piezoelectric layer 132, the third electrode 143, and the fourth electrode 144, etc. This prevents seawater or the like from entering the piezoelectric layer or the electrode parts and causing malfunctions.

[0022] A filler (not shown) may be introduced inside the cover 17. This filler is made of a material such as a silicone resin or polyurethane resin, which has a lower elastic modulus compared to the materials constituting the base material 11, the first piezoelectric layer 131, and the second piezoelectric layer 132. This prevents seawater or the like from entering the piezoelectric layer or the electrode portion and causing malfunctions.

[0023] Figure 5 is a front view showing the deformation state of the wave power generation device 10 of this embodiment during power generation, and is a cross-sectional view at cross-section BB in Figure 2. Figure 6 is also a front view showing the deformation state of the wave power generation device 10 of this embodiment during power generation, and is a cross-sectional view at cross-section CC in Figure 2. Figures 5 and 6 illustrate the state in which the wave power generation device 10 is deformed when waves or the like act on the wave power generation system 50.

[0024] As shown in Figure 5, when the left and right floating bodies 51 and the wave power generation device 10 are located near the wave crest M (Figure 1) on the water surface, the left and right floating bodies 51 are arranged in an upward-convex shape (vertical direction Z), and a bending moment P acts on the wave power generation device 10.

[0025] Because the combined structure of the base material 11 and the joint 12 has a zigzag shape along direction X, a bending moment P causes a bending moment R to act on each of the base materials 11, the first piezoelectric layer 131, and the second piezoelectric layer 132, etc., causing each of the base materials 11, the first piezoelectric layer 131, and the second piezoelectric layer 132, etc., to deform in the bending direction. The direction in which the bending moment R acts and the direction of deformation alternate in the order in which the base materials 11, the first piezoelectric layer 131, and the second piezoelectric layer 132, etc. are arranged along direction X. Furthermore, this structure superimposes the deformation, causing the entire wave power generation device 10 to deform significantly into an upward-convex shape (vertical direction Z).

[0026] Furthermore, as shown in Figure 6, when the left and right floating bodies 51 and the wave power generation device 10 are located near the wave trough N (Figure 1) on the water surface, the left and right floating bodies 51 are arranged in a convex shape (vertical direction Z), and a bending moment Q acting on the wave power generation device 10 is in the opposite direction to the bending moment P.

[0027] Because the combined structure of the base material 11 and the joint 12 has a zigzag shape along direction X, a bending moment S acts on each of the base material 11, the first piezoelectric layer 131, and the second piezoelectric layer 132 due to the bending moment Q, causing each of the base material 11, the first piezoelectric layer 131, and the second piezoelectric layer 132 to deform in the bending direction. The direction in which the bending moment S acts and the direction of deformation alternate in the order in which the base material 11, the first piezoelectric layer 131, and the second piezoelectric layer 132 are arranged along direction X. Furthermore, due to this structure, the deformation is superimposed, causing the entire wave power generation device 10 to deform significantly into a downward-convex shape (vertical direction Z).

[0028] Figure 7 is a front view (cross-sectional view) showing the deformation state of the base material 11, the first piezoelectric layer 131, and the second piezoelectric layer 132 of the wave power generation device 10 of this embodiment, and is an enlarged view of region E in Figure 5. Figure 8 is a front view (cross-sectional view) showing the deformation state of the base material 11, the first piezoelectric layer 131, and the second piezoelectric layer 132 of the wave power generation device 10 of this embodiment, and is an enlarged view of region F in Figure 6. Figures 7 and 8 show the state in which the wave power generation device 10 is deformed when waves or the like act on the wave power generation system 50.

[0029] As shown in Figure 7, when a bending moment R acts on the substrate 11, the first piezoelectric layer 131, and the second piezoelectric layer 132, etc., the substrate 11, the first piezoelectric layer 131, and the second piezoelectric layer 132, etc. deform as shown in Figure 7. State T (dotted line) is the external shape of the substrate 11, the first piezoelectric layer 131, and the second piezoelectric layer 132, etc. when no bending moment is acting, and corresponds to the state of region D in Figure 3. As a result of this deformation, tensile stress is generated in the first piezoelectric layer 131 along the main plane direction (vertical direction in Figure 7), and the piezoelectric effect of the first piezoelectric layer 131 generates a potential difference between the first electrode 141 and the second electrode 142. In addition, compressive stress is generated in the second piezoelectric layer 132 along the main plane direction (vertical direction in Figure 7), and the piezoelectric effect of the second piezoelectric layer 132 generates a potential difference between the third electrode 143 and the fourth electrode 144.

[0030] As shown in Figure 8, when a bending moment S acts on the substrate 11, the first piezoelectric layer 131, and the second piezoelectric layer 132, etc., the substrate 11, the first piezoelectric layer 131, and the second piezoelectric layer 132, etc. deform as shown in Figure 8. State T (dotted line) is the external shape of the substrate 11, the first piezoelectric layer 131, and the second piezoelectric layer 132, etc. when no bending moment is acting, and corresponds to the state of region D in Figure 3. As a result of this deformation, compressive stress is generated in the first piezoelectric layer 131 along the main plane direction (vertical direction in Figure 8), and the piezoelectric effect of the first piezoelectric layer 131 generates a potential difference between the first electrode 141 and the second electrode 142 that is opposite in sign to that in Figure 7. In addition, tensile stress is generated in the second piezoelectric layer 132 along the main plane direction (vertical direction in Figure 8), and the piezoelectric effect of the second piezoelectric layer 132 generates a potential difference between the third electrode 143 and the fourth electrode 144 that is opposite in sign to that in Figure 7.

[0031] As shown in Figures 7 and 8, the first electrode 141 located between the first piezoelectric layer 131 and the substrate 11 may be connected by a first wiring 151 to the main surface of the first piezoelectric layer 131 that is furthest from the substrate 11. Furthermore, the third electrode 143 located between the second piezoelectric layer 132 and the substrate 11 may be connected by a second wiring 153 to the surface of the second piezoelectric layer 132 that is furthest from the substrate 11.

[0032] Wiring (not shown) connected to the first electrode 141, the second electrode 142, the third electrode 143, and the fourth electrode 144 is connected to a wiring cable 52 (Figure 1), and power can be supplied to external equipment via a rectifier circuit (not shown), etc.

[0033] The following explains the effects of the wave power generation device 10.

[0034] The movement of the floating body 51 due to waves, etc., changes the bending moment acting on the wave power generation device 10. This changes the bending moment acting on the multiple base materials 11, and the first piezoelectric layer 131 and second piezoelectric layer 132 provided adjacent to each base material 11. The stress acting on the first piezoelectric layer 131 and the second piezoelectric layer 132 changes, and this is converted into electrical energy by the piezoelectric effect. This makes it possible to increase the output of the wave power generation device 10.

[0035] Furthermore, because the combined structure of the base material 11 and the joint 12 has a zigzag shape along direction X, the amount of deformation of the wave power generation device 10 is the superposition of the deformation amounts of each base material 11, the first piezoelectric layer 131, and the second piezoelectric layer 132. The ability of the wave power generation device 10 to deform significantly allows the floating body 51 and the wave power generation device 10 to deform in accordance with various shapes of waves, making it possible to further increase the output of the wave power generation device 10.

[0036] By arranging the base material 11 so that its main surface direction intersects with direction X, the length of the wave power generator 10 along direction X can be reduced, and the number of floating bodies 51 and wave power generators 10 can be increased within the same length along direction X. This allows the floating bodies 51 and wave power generators 10 to deform to follow various wave shapes, enabling further increases in the output of the wave power generators 10. This effect is maximized when the main surface direction of the substrate 11 is positioned perpendicular to direction X.

[0037] By positioning the first end 111 upward or downward along the vertical Z direction relative to the second end 112, the wave power generator 10 becomes more easily deformable to follow changes in the vertical Z position of the water surface, enabling further increases in the output of the wave power generator 10.

[0038] The deformation restricting section 16 restricts the maximum deformation of the base material 11, the first piezoelectric layer 131, and the second piezoelectric layer 132, etc., so that even if an excessive bending moment acts on the wave power generator 10 due to sudden high waves, etc., the deformation restricting sections 16 can be made to collide with each other, or with the floating body 51, before the deformation restricting section 16 can collide with each other. This prevents collisions between the first electrodes 141, the third electrodes 141, the first electrodes 141 and the floating body 51, the third electrodes 141 and the floating body 51, etc., and prevents damage to the wave power generator 10. As a result, it becomes possible to set the base material 11, the first piezoelectric layer 131, and the second piezoelectric layer 132, etc. to undergo large deformations on a steady basis, enabling further increases in the output of the wave power generator 10.

[0039] Below, a wave power generation system, which is another application example of the wave power generation apparatus of this embodiment, will be described with reference to Figures 9 to 10.

[0040] Figure 9 is a front view showing the structure of the wave power generation system 60. Figure 10 is a top view showing the structure of the wave power generation system 60.

[0041] As shown in Figures 9 to 10, the wave power generation system 60 is equipped with a floating body 61, a wave power generation device 10, and wiring cables 62, and has a structure that floats on the water surface 91. As shown in Figure 10, the floating bodies 61 are arranged relative to the breakwater 65, and the wave power generator 10 connects the floating bodies 61 and the breakwater 65. The wave power generator 10 also connects the floating bodies 61 and the breakwater 65 at two positions separated in a direction intersecting the direction in which the floating bodies 61 and the breakwater 65 are connected. When each wave power generator 10 is used as a reference, the floating bodies 61 correspond to the first object, and the breakwater 65 corresponds to the second object.

[0042] As shown in Figure 9, when waves or breaking waves occur on the water surface 91, a change in the position of the water surface 91 in the vertical direction Z occurs. As a result, a change in the position of the floating body 61 along the vertical direction Z occurs, causing the floating body 61 to tilt and the wave power generation device 10 to deform.

[0043] Modifications of the above embodiment will be described below.

[0044] The base material 11 and the connecting portion 12 may be made of a single integrated component. The base material 11 and the deformation restricting portion 16 may be composed of a single integrated component. The base material 11 may be composed of multiple members made of the same material or multiple members made of different materials. The base material 11 is composed of at least a portion of a conductive material, and the portion of the conductive material may also serve as the first electrode 141 and the third electrode 143.

[0045] The second piezoelectric layer 132, the third electrode 143, the fourth electrode 144, and the second wiring 153 are optional. In this case, the movement of the floating body 51 due to waves, etc., changes the bending moment acting on the wave power generation device 10, which in turn changes the bending moment acting on the multiple base materials 11 and the first piezoelectric layer 131 provided adjacent to each base material 11. The stress acting on the first piezoelectric layer 131 changes, and this is converted into electrical energy by the piezoelectric effect. This makes it possible to increase the output of the wave power generation device 10.

[0046] The joint 12 may be composed of multiple members made of the same material or multiple members made of different materials.

[0047] In the wave power generation system 50, the number of floating bodies 51 is not limited to four, but can be multiple. Also, the floating bodies 51 are not limited to a linear arrangement, but can be arranged in a curved shape, or in a two-dimensional arrangement along both of two intersecting directions, etc. In the wave power generation system 50, the connection points of the floating bodies 51 by the wave power generation device 10 in a direction intersecting the connection direction are not limited to two distant positions, but may be one position or three or more distant positions. In the wave power generation system 60, the connection points of the wave power generation device 10 along the direction intersecting the connection direction between the floating body 61 and the breakwater 65 are not limited to two separate locations, but may be one location or three or more separate locations. The wave power generation system 60 may be equipped with wave receiving plates or the like instead of the floating body 61.

[0048] The present invention is not limited to the above embodiments and modifications, and various modifications are possible. [Explanation of symbols]

[0049] 10 Wave power generator 11 Base material 111 First end 112 Second end 12 Joint 131 First piezoelectric layer 132 Second piezoelectric layer 141 First electrode 142 Second electrode 143 Third electrode 144 The fourth electrode 51. Floating objects (first object, second object) X Alignment direction between the left floating body (first object) and the right floating body (second object)

Claims

1. A wave power generation device that connects a first object and a second object, and generates electricity by deforming the first object and the second object due to the motion of at least one of them due to wave force, A plurality of substrates, which are plate-shaped, have their main surface direction intersecting the arrangement direction of the first object and the second object, and are arranged at predetermined intervals along the arrangement direction, The first object and the substrate closest to the first object, adjacent substrates to each other, and the second object and the substrate closest to the second object are joined together, and along the direction of arrangement, the first end of the substrate and the second end located opposite the first end are alternately positioned at the same location. A first piezoelectric layer is provided at a position adjacent to one of the main surfaces of the substrate, A first electrode provided on at least a portion of one main surface of the first piezoelectric layer, A second electrode is provided on the main surface of the first piezoelectric layer opposite to the main surface on which the first electrode is provided, at least a portion of the position facing the first electrode across the first piezoelectric layer, A wave power generation device equipped with [specific features / equipment].

2. moreover, A second piezoelectric layer is provided on the substrate at a position adjacent to the main surface opposite to the main surface adjacent to the first piezoelectric layer, A third electrode provided on at least a portion of one main surface of the second piezoelectric layer, A fourth electrode is provided on the main surface of the second piezoelectric layer opposite to the main surface on which the third electrode is provided, at least a portion of which is located opposite the third electrode across the second piezoelectric layer, The wave power generation apparatus according to claim 1, comprising:

3. The wave power generation apparatus according to claim 1 or claim 2, wherein the main surface direction of the substrate is perpendicular to the arrangement direction.

4. The wave power generation apparatus according to claim 1 or claim 2, wherein the base material and the connecting portion are made of an integral member.

5. The wave power generation device according to claim 1 or claim 2, wherein the first end is positioned vertically upward or downward relative to the second end.

6. The wave power generation apparatus according to claim 1 or claim 2, comprising a deformation restricting portion that protrudes from the main surface of the substrate and restricts the maximum amount of deformation of the substrate.

7. The wave power generation apparatus according to claim 6, wherein the deformation restricting portion is located near the end of the main surface of the substrate opposite to the end where the joint portion is located.

8. The wave power generation apparatus according to claim 6, wherein the base material and the deformation restricting portion are made of an integral member.

9. The wave power generation device according to claim 1 or claim 2, comprising a deformable cover located on the outermost part of the wave power generation device.

10. The wave power generation device according to claim 9, wherein the cover has a bellows-like shape.

11. The wave power generation apparatus according to claim 9, comprising a filler material whose elastic modulus is smaller than that of the materials constituting the substrate, the first piezoelectric layer, and the second piezoelectric layer, and which is filled inside the cover.

12. The wave power generation apparatus according to claim 1, comprising two first piezoelectric layers, and a first wiring that connects a first electrode located on the surface between the first piezoelectric layer and the substrate to a first electrode located on the main surface of the first piezoelectric layer furthest from the substrate.

13. The wave power generation apparatus according to claim 2, comprising two of the second piezoelectric layers, and a second wiring that connects the third electrode located on the surface between the second piezoelectric layer and the substrate to the third electrode located on the main surface of the third piezoelectric layer furthest from the substrate.

14. The wave power generation device according to claim 1 or claim 2, wherein the first object is a floating body and the second object is a floating body.

15. The wave power generation device according to claim 1 or claim 2, wherein the first object is a floating body and the second object is a fixed body.

Images