WO2019066650A1

WO2019066650A1 - Energy harvester and method of manufacturing such an energy harvester

Info

Publication number: WO2019066650A1
Application number: PCT/NL2018/050637
Authority: WO
Inventors: Wouter Pieter Van Zoest; Sjoerd VAN BRACHT
Original assignee: Kinergizer Ip Bv
Current assignee: Kinergizer Ip Bv
Priority date: 2017-09-29
Filing date: 2018-09-26
Publication date: 2019-04-04
Anticipated expiration: 2020-03-29
Also published as: NL2019648B1

Abstract

Récupérateur d'énergie (1) comprenant des bornes de sortie électrique (2, 3), un aimant et une bobine électrique (4) directement ou indirectement connectée auxdites bornes (2, 3), ainsi qu'un ensemble (6) d'un premier cadre (7) et d'un second cadre (8) positionné à l'intérieur du premier cadre (7) et relié à celui-ci à l'aide d'au moins un élément flexible (5) ou un joint flexible qui supporte le second cadre (8) à l'intérieur du premier cadre (7), et le second cadre (8) étant mobile par rapport au premier cadre (7) et étant équipé pour loger l'un parmi l'aimant et la bobine électrique (4) tandis que l'autre parmi l'aimant et la bobine électrique (4) est fixe par rapport au premier cadre (7) de manière à ce qu'un déplacement de la bobine électrique (4) par rapport à l'aimant provoque l'apparition d'une puissance électrique au niveau des bornes de sortie électrique (2, 3), et le ou les éléments flexibles (5) ou joints flexibles étant incorporés dans une substance à l'état liquide qui est solidifiée avec l'élément flexible (5) ou joint flexible incorporé à l'intérieur de celle-ci et laquelle substance solidifiée forme une partie du premier cadre (7) et du second cadre (8) ou est reliée à ceux-ci.Energy recuperator (1) comprising electrical output terminals (2, 3), a magnet and an electric coil (4) directly or indirectly connected to said terminals (2, 3), and an assembly (6) of a first frame (7) and a second frame (8) positioned inside the first frame (7) and connected thereto by means of at least one flexible element (5) or a flexible joint which supports the second frame (8) within the first frame (7), and the second frame (8) being movable relative to the first frame (7) and being equipped to house one of the magnet and the electric coil (4) while the other one of the magnet and the electric coil (4) is fixed with respect to the first frame (7) so that a displacement of the electric coil (4) relative to the magnet causes the occurrence of electrical power at the electrical output terminals (2, 3), and the at least one flexible member (5) or flexible joint being incorporated into a substance in the liquid state which is solidified with the flexible element (5) or flexible joint incorporated therein and which solidified substance forms part of the first frame (7) and the second frame (8) or is connected to these.

Description

Energy harvester and method of manufacturing such an energy harvester

The invention relates to a method of manufacturing an energy harvester, and such an energy harvester comprising electrical outlet terminals, a magnet and an electrical coil directly or indirectly connected to said terminals, as well as an assembly of a first frame and a second frame positioned within the first frame and connected thereto with at least one flexible element or flexure that supports the second frame within the first frame, and wherein the second frame is movable with reference to the first frame and is equipped to house one of the magnet and the electrical coil whereas the other of the magnet and the electrical coil is fixed relative to the first frame so as to arrange that movement of the electrical coil and magnet relative to each other causes electrical power to appear at the electrical outlet terminals.

Such an energy harvester is known from GB-A-2 446

685.

GB-A-2 311 171 discloses a device for producing electricity from vibrational energy, comprising a housing; a coil arranged within the housing; at least one permanent magnet ar^¬ ranged within the housing; and resilient mounting means supporting one of the coil or the magnet, whereby vibration of the housing causes relative movement between the coil and mag^¬ net thereby generating an electromagnetic force.

In general it is possible that the electrical coil connects to the outlet terminals and that externally from the energy harvester the output power available at the outlet ter- minals is conditioned. It is however also possible that the electronics for conditioning the power from the electrical coil are embedded in the energy harvester, to provide directly usable power at the outlet terminals.

A problem in the construction of energy harvesters is accuracy in positioning the second frame with reference to the first frame. This problem is connected with the desired deflection characteristics of the second frame with reference to the first frame which are determinative for the dynamic char- acteristics of the energy harvester and the power that can be generated with the harvester.

It is known to apply screw or glue connections between the at least one flexible element or flexure and the first frame and second frame, but in all known types of connection providing an exact and stress-free placement is a -difficult task.

The invention aims at providing a solution for this problem.

JP2013-126337 discloses a power generation apparatus, provided with a frame portion, a vibrating portion disposed inside the frame portion, and a pair of torsion spring portions arranged to sandwich the vibrating portion therebetween and supported by the frame portion. The power generat- ing device includes two pairs of permanent magnets which are arranged to face each other with the vibrating portion and a planar coil mounted on the vibrating portion interposed therebetween. Electrical wiring through the torsion spring portions electrically connects the planar coil with an electrical out- put of the power generating apparatus.

JP2014-204481 discloses an energy conversion device provided with a magnet block that has a magnet, and a coil block that has a coil, wherein the magnet block and the coil block are oppositely positioned with respect to each other. Relative displacement of the magnet block and the coil block arranges for electromagnetic induction in the coil of the coil block. A movable main body portion holds one of the magnet block and the coil block. The movable main body portion is mounted in a vibration block and is supported by elastic body portions that are integrally formed with the movable main body portion. The material of the movable main body portion and the elastic body portions is provided by injection moulding, for instance using polyacetal. Also other electrically not conductive material can be used such as polyphenylene sulfide, poly- amide, polytetrafluoroethylene or the like.

WO2005/022726 discloses an electromagnetic generator comprising a multilayer assembly of a first layer carrying at least one magnet, a second layer carrying at least one coil, and a third layer carrying at least one magnet, the at least 2018/050637

3

one magnet of the first and third layers being configured to define therebetween a region of magnetic flux in which the at least one coil is disposed, at least one of the layers being shaped to define a respective displaceable portion thereof which is displaceable by vibration of the electromagnetic generator thereby to cause a relative movement between the coil and the magnets and generate an electrical current in the coil. WO2005/022726 discloses the preamble of claim 1, wherein through the at least one flexible element or flexure that sup- ports the second frame within the first frame, electrical wiring is provided to make possible that electrical power from the coil can appear at the electrical outlet terminals of the generator. The first frame and the second frame are integrally formed using wafer technology, by etching a cut-out between both frames.

According to the invention an energy harvester and a method of manufacturing such an energy harvester are proposed in accordance with one or more of the appended claims.

Essentially the energy harvester of the invention and the method of its manufacture provides that the at least one flexible element or flexure is embedded in a substance in liquid condition that is solidified with the flexible element or flexure embedded therein and which solidified substance forms part of or connects to both the first frame and to the second frame.

In a first preferred embodiment of the invention the features are applied of providing the first frame and the second frame with receptacles that are equipped and dimensioned to receive a part of the flexible element or flexure, placing opposite parts of the at least one flexible element or flexure in said receptacles of the first frame and the second frame, therewith initially leaving room within the receptacles adjacent to the flexible element or flexure, filling the room in the receptacles with a curable substance for removal of any play between the at least one flexible element or flexure and the receptacles, and connecting the at least one flexible element or flexure to both the first frame and to the second frame by curing the curable substance in the room of the receptacles to provide a play free and stress-free connection between the at least one flexible element or flexure and the receptacles of the first frame and the second frame.

Another preferred embodiment of the invention applies the features of placing the at least one flexible element or flexure in a mould for the assembly of the first frame and the second frame, followed by moulding of the assembly of the first frame and the second frame with a plastic substance and providing said plastic substance around and against the at least one flexible element or flexure to provide an assembly wherein the at least one flexible element or flexure connects to both the first frame and the second frame.

A very suitable way of moulding would be to implement the moulding step by injection moulding rather than simply pouring the plastic substance in a mould.

In all the above-mentioned embodiments it is advanta^¬ geous to provide the at least one flexible element or flexure with through holes to receive the curable substance or the plastic so as to realize a through and through connection between the at least one flexible element or flexure and the as- sembly of the first frame and the second frame.

A further preferable feature is that the at least one flexible element or flexure provides an electrical connection between the electrical coil and the electrical outlet terminals .

The invention will hereinafter be further elucidated with reference to the drawing of exemplary embodiments of manufacturing an energy harvester according to the invention that is not limiting as to the appended claims.

In the drawing:

-figure 1 shows an assembly of an energy harvester according to a first embodiment of the invention;

-figure 2 shows a more schematic view of an assembly of an energy harvester according to the first embodiment of the invention;

-figure 3 shows a mould which may be used for manufacturing an energy harvester according to a second embodiment of the invention; -figure 4 shows the mould of figure 3 together with other elements for manufacturing the energy harvester of the invention; and

-figure 5 shows the mould of figure 3 after injection moulding and prior to releasing the assembly of the first frame and second frame from the mould.

Whenever in the figures the same reference numerals are applied, these numerals refer to the same parts.

Making reference first to figure 1 a first preferred embodiment of an energy harvester 1 according to the invention is shown comprising electrical outlet terminals 2, 3 and an electrical coil 4 connected to said terminals 2, 3. The electrical coil 4 is connected to the terminals 2, 3 through flex- ural elements 5 or flexures with electrically conductive prop- erties, preferably comprising copper, which flexural elements 5 or flexures are also used for (indirectly) supporting the electrical coil 4 in the manner as will be discussed hereinafter.

Figure 1 further shows that the energy harvester 1 comprises an assembly 6 of a first frame 7 and a second frame 8. The second frame 8 is positioned within the first frame 7 and is connected thereto with -in this first preferred embodiment- two flexible elements 5 or flexures that support the second frame 8 within the first frame 7. The second frame 8 is equipped to house the electrical coil 4 which is movable through movement of the second frame 8 with reference to the first frame 7. The flexures 5 are therefore designed to provide sufficient flexibility in the support of the second frame 8, so that it can move with reference to the first frame 7 when the energy harvester 1 is subjected to external vibrations .

To support the energy harvesting or energy conversion by the energy harvester 1 the assembly 6 is further equipped to directly or indirectly support at least one magnet (not shown since this is clear to the skilled person} which is fixed relative to the first frame 7 so as to arrange that movement of the electrical coil 4 within the magnet's magnetic field causes electrical power to appear through induction at the electrical outlet terminals 2, 3 that connect to the elec- trical coil 4. For this purpose it is preferred that the flexible elements 5 or flexures provide an electrical connection between the electrical coil 4 and the electrical outlet terminals 2, 3.

It is pointed out that instead of the electrical coil

4 being housed in the second frame 8, it is also possible to have the electrical coil 4 and the magnet change position, so that the magnet will be housed in the second frame 8 and that the electrical coil will be directly or indirectly supported by the assembly 6 and assume a fixed positidn with reference to the first frame 7. The particular position of the electrical coil and the magnet is therefore not essential to the invention.

As can be best seen in figure 1, but also making ref- erence to figure 2, the flexible elements 5 or flexures are connected to both the first frame 7 and to the second frame 8 in receptacles 9, 10 that are provided in the first frame 7 and second frame 8 respectively. The receptacles 9, 10 are equipped and dimensioned to receive opposite extremities of one flexible element 5 or flexure, therewith (initially) leaving some room within the receptacles 9, 10 adjacent to the concerning flexible element 5 or flexure. This room is subse^¬ quently filled with a curable substance for completely filling up the room and remove any play between the concerning flexi- ble element 5 or flexure and the respective receptacles 9, 10. This can be best seen in figure 1. Figure 2 clearly shows that after the curable substance in the receptacles 9, 10 is cured a play free and stress-free connection is provided between the flexible elements 5 and the receptacles 9, 10 of the first frame 7 and the second frame 8. A suitable curable substance to be used may for instance be a plastic substance or an epoxy resin with adhesive properties. Other substances may however be equally suitable. One may for instance also use substances that solidify when combined with another substance, or sub- stances that solidify when raising the temperature.

A second preferred embodiment of the energy harvester of the invention and its method of manufacturing is elucidated in the following with reference to figures 3 - 5. In figure 3 a mould 11 is shown that can be used for manufacturing an assembly of a first frame and second frame together with flexible elements that eventually will provide a supporting connection between the first frame and second frame which are to be made in the mould 11. The mould 11 comprises mould parts 15, 16 and 17. Mould parts 15 and 16 border a space 12 for the first frame to be moulded, and mould parts 16 and 17 border a space 21 for the second frame to be moulded.

Reference 14 indicates a slit in which eventually a flexible element or flexure is to be mounted, and which will extend on the one hand with one of its extremities into a partial space 18 forming part of the space 12 in which the first frame part will be formed, and on the other hand into the space 13 which is saved for receiving another end or extremity of the flexible element or flexure.

Figure 4 again shows the mould 11, and in addition the two flexible elements 5, parts of which are to be received in the slits 14 of the mould 11. Figure 4 also shows a covering plate 19 which is only required when the moulding step is done by injection moulding. For injection moulding the covering plate 19 will be provided on the side of the mould 11. Af^¬ ter placement of the covering plate 19 on the mould 11, the mould 11 can be injected with an injectable plastic substance that is provided around and against the flexible elements 5 or flexures to provide an assembly of the first frame and the second frame and wherein the flexible elements 5 or flexures connect to both the first frame and the second frame being moulded. Figure 5 shows the assembly of the first frame 7, the second frame 8 and the flexures 5 at the end of the moulding process and before being removed from the mould 11. Thereafter the assembly can be removed from the mould 11.

Turning back to figure 4, this figure further shows that the flexible elements 5 are provided with through holes 20. The flexible elements 5 as shown in this figure 4 are preferably also used in the first preferred embodiment of figures 1 and 2, wherein the through holes 20 are intended to receive the curable substance according to said first preferred embodiment. In the second preferred embodiment of figures 3 - 5 the through holes 20 receive the plastic substance that is injected in the mould 11 according to the second embodiment, so as to realize a through and through connection between the flexible elements 5 and the assembly of the first frame 7 and the second frame 8.

Although the invention has been discussed in the foregoing with reference to exemplary embodiments of a method of manufacturing the energy harvester of the invention, the invention is not restricted to these embodiments which can be varied in many ways without departing from the invention. The discussed exemplary embodiments shall therefore not be used to construe the appended claims strictly in accordance therewith. On the contrary the embodiments are merely intended to explain the wording of the appended claims without intent to limit the claims to these exemplary embodiments. The scope of protection of the invention shall therefore be construed in accordance with the appended claims only, wherein a possible ambiguity in the wording of the claims shall be resolved using these exemplary embodiments.

Claims

1. Energy harvester (1) comprising electrical outlet terminals (2, 3), a magnet and an electrical coil (4) directly or indirectly connected to said terminals (2, 3) , as well as an assembly (6) of a first frame (7) and a second frame (8) positioned within the first frame (7) and connected thereto with at least one flexible element (5) or flexure that sup^¬ ports the second frame (8) within the first frame (7), and wherein the second frame (8) is movable with reference to the first frame (7) and is equipped to house one of the magnet and the electrical coil (4) whereas the other of the magnet and the electrical coil (4) is fixed relative to the first frame (7) so as to arrange that movement of the electrical coil (4) and the magnet relative to each other causes electrical power to appear at the electrical outlet terminals (2, 3), charac- terized in that the at least one flexible element (5) or flexure is embedded in a substance in liquid condition that is solidified with the flexible element (5) or flexure embedded therein and which solidified substance forms part of or connects to both the first frame (7) and to the second frame (8) .

2. Energy harvester according to claim 1, characterized in that the at least one flexible element (5) or flexure is partly received in receptacles (9, 10) that are provided in both the first^' frame (7) and the second frame (8), which receptacles (9, 10) are equipped and dimensioned to receive op- posite parts of the at least one flexible element (5) or flexure, therewith initially leaving room within the receptacles (9, 10) adjacent to the at least one flexible element (5) or flexure, which room is filled with a curable substance for removal of any play between the at least one flexible element (5) or flexure and the receptacles (9, 10), and which curable substance is cured to provide a play free and stress-free connection between the at least one flexible element (5) or flexure and the receptacles (9, 10) of the first frame (7) and the second frame (8) .

3. Energy harvester according to claim 1, characterized in that the assembly (6) of the first frame (7) and the second frame (8) is formed by moulding with a plastic sub- stance that is provided around and against part of the at least one flexible element (5) or flexure to provide an assem^¬ bly wherein the at least one flexible element (5) or flexure connects to both the first frame (7) and the second frame (8) .

4. Energy harvester according to claim 4, characterized in that the assembly (6) of the first frame (7} and the second frame (8) is formed by injection moulding.

5. Energy harvester according to any one of claims 1

- 4, characterized in that the at least one flexible element (5) or flexure is provided with through holes (20) to receive the curable substance or the plastic substance so as to real^¬ ize a through and through connection between the at least one flexible element (5) or flexure and the assembly (6) of the first frame (7) and the second frame (8) .

6. Energy harvester according to any one of claims 1

- 5, characterized in that the at least one flexible element

(5) or flexure provides an electrical connection between the electrical coil (4) and the electrical outlet terminals (2, 3) .

7. Method of manufacturing an energy harvester (1) comprising electrical outlet terminals (2, 3), a magnet and an electrical coil (4) directly or indirectly connected to said terminals (2, 3), comprising the step of providing an assembly

(6) of a first frame (7) and a second frame (8) positioned within the first frame (7) and connected thereto with at least one flexible element (5) or flexure that supports the second frame (8} within the first frame (7), and providing that the second frame (8) is movable with reference to the first frame

(7) and houses one of the magnet and the electrical coil (4) whereas the other of the magnet and the electrical coil (4) is fixed relative to the first frame (7) so as to arrange that movement of the electrical coil (4) and the magnet relative to each other causes electrical power to appear at the electrical outlet terminals (2, 3), characterized by providing that the at least one flexible element (5) or flexure is embedded in a substance in liquid condition that is subsequently solidified with the flexible element (5) or flexure embedded therein and providing that the solidified substance forms part of or connects to both the first frame (7) and to the second frame (8).

8 - Method of manufacturing an energy harvester according to claim 7, characterized by providing the first frame (7) and the second frame (8) with receptacles (9, 10) that are equipped and dimensioned to receive part of the at least one flexible element (5) or flexure, placing opposite parts of the at least one flexible element (5) or flexure in said recepta^¬ cles (9, 10} of the first frame (7) and the second frame (8) respectively, therewith leaving room within the receptacles (9, 10) adjacent to the at least one flexible element (5) or flexure, filling the room in the receptacles (9, 10) with a curable substance for removal of any play between the at least one flexible element (5) or flexure and the receptacles (9, 10), and connecting the at least one flexible element (5) or flexure to both the first frame (7) and to the second frame (8) by curing the curable substance in the room of the receptacles (9, 10) to provide a play free and stress-free connection between the at least one flexible element (5) or flexure and the receptacles (9, 10) of the first frame (7) and the second frame (8) .

9. Method of manufacturing an energy harvester according to claim 7, characterized by placing the at least one flexible element (5) or flexure in a mould {11) for the assembly of the first frame (7) and the second frame (8), followed by moulding of the mould (11) for the assembly of the first frame (7) and the second frame (8) with a plastic substance and providing said plastic substance around and against the at least one flexible element (5) or flexure to provide an assembly (6) wherein the at least one flexible element (5) or flexure connects to both the first frame (7) and the second frame (8) .

10. Method of manufacturing an energy harvester according to claim 7, characterized by providing that the moulding is done by injection moulding.

11. Method of manufacturing an energy harvester ac- cording to any one of claims 7 - 10, characterized by providing the at least one flexible element (5) or flexure with through holes (20) to receive the curable substance or the plastic substance so as to realize a through and through connection between the at least one flexible element (5) or flex- ure and the assembly of the first frame (7) and the second frame ( 8 ) .

12. Method of manufacturing an energy harvester according to any one of claims 7 - 11, characterized by provid- ing the at least one flexible element (5) or flexure acts an electrical connector between the electrical coil (4) and the electrical outlet terminals {2, 3) .