EP2823555A1

EP2823555A1 - Electrostatic device and method for recovering mechanical energy by triboelectric effect

Info

Publication number: EP2823555A1
Application number: EP13709179.9A
Authority: EP
Inventors: Ghislain Despesse; Sébastien Boisseau; Dominique Vicard
Original assignee: Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Current assignee: Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Priority date: 2012-03-05
Filing date: 2013-03-05
Publication date: 2015-01-14
Also published as: FR2987708A1; WO2013131915A1; US20150035408A1; FR2987708B1

Abstract

A device for recovering energy comprising a first assembly (E1) and a second assembly (E2) facing each other, the first assembly (E1) comprising a first conductive element (2) and a first dielectric element (6) carried by the first conductive element (2), and the second assembly (E2) comprising a second conductive element (4), said first dielectric element (6) being arranged between the first conductive element (2) and the second conductive element (4), wherein said device comprises means for ensuring that said first dielectric element (6) comes into contact with the second conductive element (4) and wherein the material of the first dielectric element (6) and the material of the second conductive element (4) are selected in such a way that they have different triboelectric affinities.

Description

ELECTROSTATIC DEVICE AND METHOD FOR RECOVERING MECHANICAL ENERGY BY TRIBOELECTRIC EFFECT

DESCRIPTION TECHNICAL FIELD AND PRIOR ART

The present invention relates to an electrostatic device for recovering mechanical energy from electrical energy using the electrostatic charges accumulated by triboelectric effect on at least one dielectric material.

In the field of energy recovery, it is known to use variable capacity systems comprising at least one fixed electrode, and at least one moving electrode facing each other, the electrodes being separated by an air or vacuum gap. . The moving electrode is set in motion by the external vibrations and by injecting and removing a charge in the system at specific times, it is possible to convert the vibratory energy into electrical energy.

These systems also require a polarization of the structure at each cycle to perform energy recovery cycles. This polarization requires electronic means for the transfer of electrical charges to the electrostatic structure, to always have a minimum energy and to make a detection of the maximum capacity. This generates significant electrical losses, and makes the system very complex.

It is also known to use electrets to permanently bias the electrodes. In this case, it is no longer necessary to polarize the structure at each cycle; management of the injection and the withdrawal of charges is no longer required. As a reminder, an electret is an electrical insulating material having a state of quasi-permanent electric polarization. It is generally obtained by dipolar orientation or by injection of charges. An electret makes it possible in particular to impose a permanent polarization in a capacitive structure, however it does not make it possible to conduct the current. In addition, there are several types of electrically biased energy recovery converter structures. These different types are described in the document "Microstructures electrostatic vibratory energy recovery for microsystems" S. BOISSEAU, G. DESPESSE 1-1 CHAILLOUT and A. SYLVESTRE, in Techniques of the engineer, 10-2010, RE 160, pp. 1-12.

The first type is an out-of-plane structure. An electrode and a counter electrode are disposed opposite each other, one carrying the electret. The two electrodes are adapted to move towards and away from each other and define between them a variable air gap. The whole forms a capacitor with variable capacity

This structure is particularly well suited if the vibrations are known and stable over time (in frequency and amplitude). The structure is then dimensioned so that the reference vibrations cause a maximum capacity variation: the counter electrode oscillates between a position very close to the electret and a widely separated position. However, this structure has the disadvantage that, in the case where the vibrations are too strong, the counter-electrode can strike the electret, which can release the charges stored in the electret and reduce the life of the electret and therefore the structure.

The second type of structure is the structure in the plane, implementing structured electrets. In this structure, the electrode and the counter electrode delimit a fixed gap, but the counter-electrode moves in a single plane parallel to the electrode. The surfaces opposite vary. In order to increase the capacitance variation, the electret, the electrode and the counter-electrode are textured, for example the electrode and the counter electrode are in the form of parallel strips inclined with respect to the direction of movement of the electrode. counter electrode, the electrode strips are covered with electret. Thus the surface variation is important, which results in a significant capacitance variation. These structures are, however, more difficult to develop and their manufacturing cost is higher than the out-of-plane structures.

In addition, the stability of the electret conditions the life of the system. If the electret is discharged, the system no longer works. However, the stability of the electret can be greatly reduced when subjected to difficult conditions, by for example, a humidity greater than 30% and a temperature greater than 100 °. However, many systems are subjected punctually to conditions of this type and in particular during their manufacture. In addition, there are few materials capable of keeping their charges for long periods of time, mainly polymers such as Teflon ^® , Kapton ^® , Mylar ^® , CYTOP ^® and oxide ceramics ( SiO2) or silicon nitride (Si3N4).

Document US4126822 discloses a system generating electricity electrostatically, but this requires a precharge of the electrodes and a maintenance of this charge by complex polarization means.

The "Flexible Triboelectric Generator" document, Feng-Ru Fan, Zhong-

Qun Tian, Wang Zhong Lin, Nano describes a triboelectric energy recovery device that does not allow a recovery of significant energy, and is otherwise of an impractical use.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an energy recovery system in which problems of contact and stability of the electret charge do not arise.

The object of the present invention is obtained by a mechanical energy recovery device comprising at least a first assembly comprising a conductive element covered with a dielectric material and a second assembly comprising at least one conductive element, the two assemblies being mobile. relative to each other, the dielectric material and the second set having different triboelectric affinities. The device is such that the second set and the dielectric come into contact, which has the effect of charging the dielectric. In one embodiment, the energy is recovered between the conductive element of the first set and the conductive element of the second set. In another embodiment, the energy is recovered either on one of the sets that has several conductive elements, or on both sets separately. The charge of the dielectric is then maintained through contact with the second set.

Thus, it is not necessary to use a material that is able to hold its charge for a long time since it is "recharged" during operation.

In addition, the device becomes usable indefinitely because the dielectric is never discharged.

Finally, the contact between the second set and the dielectric is no longer a problem, on the contrary it is sought. It is therefore possible to use an off-plan structure which is simpler and less expensive than the structures in the plan.

This device has the advantage of not requiring the application of a potential difference between its conductive elements to operate.

In other words, the influence of electrostatic charges which can accumulate in the dielectric material by triboelectric effect to produce electrical energy is used. State-of-the-art devices, such as triboelectric generators or electrostatic induction machines using triboelectricity, directly collect the charges produced during contacting. On the contrary, according to the invention, these charges are not directly collected, but these are used to transform a dielectric material into electret or pseudo-electret, ie which has a shorter lifetime than that of an electret in the ordinary sense of the term, by triboelectric effect or to maintain the charge of an electret. In addition, unlike electrostatic electrostatic energy recovery devices in which means are implemented to avoid contact between the fixed and mobile parts, in the case of the device according to the invention, a contact between the fixed part and the mobile part is sought in order to recharge the dielectric material and maintain the polarization.

The choice of materials with different triboelectric affinities and the contact between these materials form means for maintaining the polarization of the device. This device has the advantage of being completely autonomous since it does not require polarization means and its polarization is maintained over time.

The subject of the present invention is therefore a method of recovering energy by means of an energy recovery device comprising a first and a second set placed facing each other and moving relative to one another. , the first assembly comprising at least a first conductive element, a first dielectric element carried by the first conductive element and the second assembly comprising at least a second conductive element, said first dielectric element being disposed between the first and the second conductive element, said first dielectric member engageable with a portion of the second set, the material of the first dielectric member and the material of the portion of the second set with which the first dielectric member contacts with different triboelectric affinities, the method having the steps of :

- Preloading the first dielectric element of the first set, the charge of this first dielectric element being wholly or partly provided by a triboelectric effect when contacting the first dielectric element and an element of the second set called contact element;

relative displacement of the first and second assemblies between a first position, said contact position, for which the first preloaded dielectric element is in contact with said contact element of the second set and has a first contact surface and a second position, said remote, for which said contact element of the second assembly is moved away from the first dielectric element so that they are no longer in contact or have a second contact surface smaller than said first contact surface, this displacement inducing a variation in capacitance between the first dielectric element and the second conductive element;

- Circulation, during said movement, of a current between the first conductive element of the first assembly and an electrical circuit, this current being induced by said relative displacement of the first and second sets and inducing electrical energy in the electrical circuit.

In a very advantageous manner, the capacitance variation between the first dielectric element and the second conductive element during said displacement is at least 20%, preferably at least 40% of the capacitance value in the so-called contact position.

The recovery method according to the invention may comprise, in the contact position, a first state of equilibrium appearing between the first conductor, the first dielectric element and the second conductive element, and in the remote position, a second state of equilibrium appearing between the first dielectric element and the first conductive element, the transition from the first equilibrium state to the other causing the flow of an electric current between the first conductive element of the first assembly and the electrical circuit.

The present invention also relates to an energy recovery device comprising a first and a second set placed opposite and movable relative to each other, the first set comprising at least a first conductive element. and a first dielectric element carried by the first conductive element, and the second assembly comprising at least a second conductive element, said first dielectric element being disposed between the first and second conductive elements, said first dielectric element being able to come into contact with a portion of the second set, the material of the first dielectric element and the material of the part of the second set with which the first dielectric element comes into contact having different triboelectric affinities, the first dielectric element of the first set being capable of presenting a charge obtained in any or part by an effect triboelectric when contacting the first dielectric element and an element of the second set called contact element, the device allowing a relative displacement of the first and second sets between a first position, said contact, for which the first dielectric element preloaded is in contact with said contact element of the second set and has a first contact surface and a second so-called remote position, for which said contact element of the second set is remote from the first dielectric element so that they are no longer in contact or have a second contact surface smaller than said first contact surface, this displacement inducing a variation of capacitance between the first dielectric element and the second conductive element, the device further comprising an electrical circuit connected to the first conductive element so that an electric current is able to circulate, during said movement, between the first conductive element of the first set and the electric circuit, this current being induced by said relative displacement of the first and second sets and inducing electrical energy in the electrical circuit.

In one embodiment, the electrical circuit connects the first conductive element and the second conductive element.

In one example, the second conductive element can form the part of the second set with which the first dielectric element comes into contact.

In another example, the second assembly comprises a second dielectric element carried by the second conductive element, and disposed between the first dielectric element and the second conductive element, the second dielectric element forming the part with which the first dielectric element comes into contact.

In another embodiment, the energy recovery device may comprise a first and a second set vis-à-vis, wherein the first set comprises at least one pair of adjacent conductive elements each covered by a dielectric element , the two dielectric elements having different triboelectric affinities, and the second set comprising at least a second conductive element having triboelectric affinity classified between the triboelectric affinities of the two dielectric elements of the first set, wherein the electrical circuit connects the at least two elements drivers of the first set. The second set may be formed by a conductive element covered with a dielectric element.

In another embodiment, each of the first and second sets comprises at least one pair of two adjacent conductive elements each covered by a dielectric element, the two dielectric elements of each pair having different triboelectric affinities, and the dielectric elements facing each other. opposite with different triboelectric affinities. The means for collecting the generated electrical energy collect the electrical energy generated between the conductive elements of each pair.

In another embodiment, each of the first and second sets comprises at least one pair of two adjacent conductive elements each covered by a dielectric element, the two dielectric elements of each pair having different triboelectric affinities, and the dielectric elements facing each other. with opposite triboelectric affinities, the conductive elements of the second set being short-circuited.

The first and second sets may be planar and parallel, with at least one of the first and second sets mounted on a frame so as to move at least perpendicular to the other conductive assembly.

The first and second sets can be flat and parallel. The first set may be structured and the second set may be structured so that, upon a displacement of the first and / or second set in a direction parallel to the first and second sets, a capacity variation occurs between the one or more dielectric elements of the first set and the second set.

In an exemplary embodiment, the first and / or second set comprises a plurality of wires each comprising a core and an envelope, the core forming a conductive element and the envelope forming a dielectric element. The threads can be woven.

In one embodiment, at least the second assembly may be flexible so as to move closer to the first assembly under the effect of an external force and to contacting the first element when said external force has sufficient intensity.

For example, the first and second sets are held by a support, said support being such that it deforms elastically to bring the first set and the second set together under the effect of an external force and to put them in contact when said external force has sufficient intensity.

The first set may have a curved shape in the absence of application of an external force and be remote from the second set, said first set being deformed by application of an external force and coming into contact with the second set.

In another embodiment, the two sets are in constant contact.

According to an additional feature, the one or more dielectric elements are compressible.

In an exemplary embodiment, at least one of the assemblies may have a rotational movement about an axis of rotation. In one embodiment, the first and second assemblies may be disk-shaped, at least one of the assemblies being rotatable about its axis, the axes of the first and second assemblies being secant, the two assemblies being in permanent contact with each other. their edges, the disk of the first set being divided into angular sectors, angular sectors being covered by the first dielectric element and angular sectors not being covered by the first dielectric element.

In another embodiment, the first and second sets may be parallel, the first set having the shape of a disk and being divided into angular sectors, first angular sectors being covered by the first dielectric element and second angular sectors being or n not being covered by the first dielectric element, the first angular sectors being in permanent contact with the second assembly. The second set can then have the shape of a disk, the axes of the disks being merged with the axis rotation. The second set may be rotating and have the shape of an angular sector movable in rotation about the rotation axis.

The present invention also relates to a system comprising at least two energy recovery devices according to the present invention connected in parallel or series.

The present invention also relates to a system comprising at least one energy recovery device according to the present invention and storage means of the recovered energy before its transfer to the use circuit.

The system may comprise at least one communicating sensor capable of measuring, of processing it and of transmitting it by radio means to a receiver as soon as the quantity of energy stored in the storage means is greater than a given threshold.

The present invention also relates to a garment comprising at least one device according to the present invention or a system according to the present invention, the first assembly and the second assembly being carried by two parts of the garment vis-à-vis and intended to move relative to each other and to come into contact, for example these two pieces being formed by two legs of pants.

The present invention also relates to a tire for a motor vehicle comprising at least one recovery device according to the present invention or a system according to the present invention, one of the sets of the device being fixed on an inner face of a tread. of the tire.

The tire or garment may comprise means for processing the variation of the current or the electrical voltage recovered as a function of time in order to determine information on the tire, such as the speed of rotation, the pressure, the temperature or the acceleration , or the relative displacement of the pieces of clothing.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood with the aid of the description which follows and the drawings in appendices in which: FIGS. 1A and 1B are schematic side views of an example of a first embodiment of a system for recovering energy in two operating states,

FIGS. 2A and 2B are schematic side views of another example of the first embodiment of a system for recovering energy in two operating states,

FIG. 3 is a schematic sectional view of another embodiment of a recovery device according to the first embodiment in the form of wires,

FIG. 4 is a schematic side view of an example of an energy recovery device according to a second embodiment,

FIG. 5 is a schematic side view of another example of an energy recovery device according to the second embodiment,

FIG. 6 is a schematic view of a variant of the device of FIG. 5,

FIG. 7 is another embodiment of the first embodiment in which the assemblies are structured,

FIGS. 8 to 11 are examples of embodiments of the recovery device according to the invention, the two sets having a relative rotational movement,

FIG. 12 is a schematic side view of an exemplary embodiment of a recovery device in which the dielectric elements are compressible,

FIG. 13 is a schematic representation of a tire to which a device of the invention can be applied,

FIG. 14 is a graphical representation of the radial acceleration of a point on the tire surface as a function of time,

FIG. 15 is a graphical representation of the variation of electric current recovered by a device according to the invention mounted in a tire as a function of time, FIGS. 16, 17, 18A and 18B are diagrammatic side views of various embodiments of the structure of the device of FIGS. 1A and 1B, particularly adapted to the recovery of energy in a tire,

FIG. 19 is a schematic representation of a garment equipped with a recovery device according to the present invention,

- Figure 20 is a schematic representation of a device applied to a sweater.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

In the following description, the same references will be used to describe the elements having substantially the same form and the same function in all the exemplary embodiments.

In the present application, the term "electrical capacitance between a conductive element and a charged dielectric element" means the capacitance equivalent with respect to the conductive element charged by the electrical charges stored in the dielectric element. If for example the charges are stored at a certain depth of the dielectric element, the equivalent capacitance is the capacity that would form an electrode placed at this depth relative to the conductive element. In practice, the charges can be stored at different depths in the dielectric element. The electrical capacitance between a conductive element and a charged dielectric element then means an equivalent overall capacitance which charged with the electret's surface potential would store the same amount of energy as the total electrical energy which is stored as charges. Distributed electrical power (y2C _eq V _on f _ace ² = Σ½Associated elements - V _{asso ciated} being the potential difference between each of the ele- ments Qi implanted and the conductive element).

Furthermore, in the present application, the term "electrical capacitance between two charged dielectric elements" is understood to mean the equivalent electrical capacitance which the differential charges charge in the two dielectric elements. The interaction energy between the charges stored in each of the two dielectric elements is substantially ½Q. ² / C _e q _U ivaient Q ² with the charge difference between the first and second dielectric elements and C _equiV have the electrical capacitance between two charged dielectric elements).

In FIGS. 1A and 1B, we can see a first example of an energy recovery system according to a first embodiment comprising a first set El and a second set E2 arranged vis-à-vis. The first set El comprises a first conductive element 2 having the shape of a plate, covered with a first dielectric element 6, and the second set E2 comprises a second conductive element 4 in the form of a plate. The dielectric element 6 is located between the first 2 and second 4 conductive elements.

The first 2 and second 4 conductive elements are electrically connected through a power consumption circuit 8, which is for example a lamp, a sensor, a battery charger ..., or a storage device, battery type.

The first set E1 and the second set E2 are such that they are able to move towards and away along the Z axis under the effect of an external action, for example vibrations or deformations. For example, only the second set E2 is movable along the Z axis and is suspended, for example by springs to a support (not shown) with respect to which the first set El is fixed.

The device is such that the amplitude of displacement is significant of the second set E2 with respect to the first set E1, ie the displacement of the second set E2 is sufficient to allow the second conductive member 4 to come into contact with the first dielectric element 6. The variation in capacity is preferably at least 20%, and more preferably at least 40%. Advantageously, the gap variation between the two dielectrics is at least ΙΟμιη, so as to cause a capacitance variation of at least 20%, advantageously at least 50μιη so as to cause a variation of capacity of at least 40% advantageously.

A device in which the two sets would be movable along the Z axis and a device in which only the first set comprising the first conductive element and the dielectric element would be mobile are not outside the scope of the present invention.

The material of the dielectric element 6 and the material of the second conductive element 4 are chosen such that they have different triboelectric affinities, ie when the two materials come into contact they exchange electrons, one having a tendency to give away electrons while the other tends to capture them. The materials are classified according to their ability to donate or capture electrons in a list called "Triboelectric Series" an example of which is given below.

Materials with positive affinity

Dry hands

Rabbit fur

Glass

Hair

Nylon

Wool

Cat fur

Silk lead

Aluminum

Paper

Cotton

Stainless steel

Wood, amber, resin

Sulfur

Hard rubber (ebonite)

Nickel, copper,

Brass, silver,

Gold, platinum

Polyester

polystyrene

polyurethane polyethylene

polypropylene

Polyvinyl chloride

Silicone

Teflon

Negative affinity materials

It is conceivable to implement elements that are close in the triboelectric series but it is advantageous to choose materials that are distant in the series, so as to facilitate the exchange of electrons at each contact. The positive or negative affinity of a material is defined relative to another material.

In the example shown, the material of the second conductive element is chosen such that it has a tendency to give up electrons, and the material of the dielectric element is chosen such that it tends to pick up electrons. Thus the electrons picked up or torn off will be trapped in the material of the dielectric element. The presence and the absence of electrons are symbolized by signs - and + respectively in FIGS. 1A and 1B. Conversely, it is also possible to choose another pair of materials such that the dielectric provides the electrons which are then picked up by the metal.

During the manufacture of the device, the dielectric element may not be charged and be charged during operation of the device from the first contact with the second conductive element 4, each contact reloading the dielectric element. Alternatively, the dielectric element is already charged, so it is an electret. Its charge is maintained by contact with the second conductive element 4. Indeed, the electret can lose charges over time, for example because of self-discharge phenomena of the material. In some cases, a contact between an electret and a conductor may also lead to a loss of electret charges: the charges from the electret may pass into the conductor. By choosing materials with different triboelectric affinities, such a problem is avoided. Preferably, couples that are as far apart as possible in the triboelectric list are selected to maximize the efficiency of the energy recovery system. We can choose for example couples: Gold / Teflon, Lead / Teflon, Brass / Nylon,

Aluminum / Teflon ...

We will now explain the operation of the energy recovery device of Figures 1A and 1B.

We consider the case where initially the dielectric element 6 is already charged with a load Qj. The load Q.2 is the load induced by the dielectric element loaded on the first conductive element 2 and the load Q4 is the load induced by the dielectric element 6 charged on the second conductive element 4. According to the law of conservation the load Qj = Q.2 + Q.4.

There is a capacitance C1 between the dielectric element and the first conductive element 2, and a capacitance C2 between the dielectric element 6 and the second conductive element 4.

The second conductive element 4 is caused to vibrate by an external event, which then moves along the axis Z towards and away from the dielectric element 6. The electrostatic influence exerted by the charges of the dielectric element 6 on the first 2 and second 4 conductive elements varies over time as a function of the distance separating the charged dielectric element 6 and the second conductive element 4. This causes a new distribution of the charges between the conductive elements 2 and 4 .

When the second conductive element 4 is moved away from the dielectric element 6 (FIG. 1A), the assembly formed by the first conductive element 2 and the dielectric element tends to become neutral and the capacitance C1 is much greater than the capacitor C2.

Then, when the second conductive element 4 approaches the dielectric element 6, it goes under the electrostatic influence of the charged dielectric element and is charged, through the circuit 8, so as to balance the load of the element dielectric capacitance C2 deviates significantly with respect to the capacitance Cl. The variation of the influence of the charges of the dielectric element on the second conductive element 4 is symbolized by the increase of the charges on the second conductive element in FIG. 1B (Figure 1B shows a level of charge on the electrode 4 greater than the charge on the electrode 4 in FIG. 1A before bringing the electrode 4 of the electrode 6 closer together.

A redistribution of the charges then takes place between the first 2 and the second 4 conductive elements through the circuit 8, which generates an electric current through the circuit 8 and an electrical voltage at its terminals. Part of the mechanical energy that has set in motion the second conductive element is thus converted into electrical energy.

The second conductive element 4 comes into contact with the charged dielectric element 6 (FIG. 1B) and because of their different triboelectric affinities exchange charges, more particularly in the example shown, the second conductive element 4 yields electric charges. and the dielectric element 6 pulls electrical charges. The charge of the dielectric element is then maintained over time and the energy recovery device remains functional. The contact between the dielectric element 6 and the second conductive element 4 may take place due to a displacement mainly along the Z axis. It may be envisaged that the second conductive element 4 and the dielectric element will slide one on the other in a direction perpendicular to the Z axis.

The captured charges (electrons or lack of electron (holes)) by the dielectric element remain mainly on the surface. It should be noted that an electret charged or recharged by triboelectricity, is of a lower quality compared to a "standard" electret. Indeed, its stability is generally low for various reasons and in particular because the charges remain localized rather on the surface. However, thanks to the device according to the invention, it is reloaded regularly by friction, this lower quality has no impact on the efficiency and life of the system. Moreover, this electret may have a lower cost than electrets able to keep their charges over long periods; in addition a greater choice of usable materials is available.

This exemplary embodiment has a small footprint, in fact its thickness is low. Each conductive element may be formed by an aluminum film, the first conductive element being covered with Teflon. The elements conductors have for example a thickness of between 100 nm and 10 mm. The dielectric has for example a thickness between 10 nm and 1 mm.

The contact between the dielectric element 6 and the second conductive element 4 is globally random. However, the system is dimensioned so that contact between the dielectric element 6 and the conductive element 4 takes place at a frequency sufficient to allow the dielectric element to be recharged, for example at least once a day, for example at the moment of maximum travel between the dielectric element 6 and the conductive element 4.

Due to the triboelectric effects, the dielectric element has a natural tendency to charge up to a maximum value which is proportional to their triboelectric affinity difference. Thus, very advantageously, the amount of charge present in the dielectric element has, in practice, no need to be precisely controlled. The order of magnitude for this quantity is mC / m ² and can reach up to 10-15 mC / m ² .

In FIGS. 2A and 2B, another exemplary embodiment according to the first embodiment of an energy recovery device can be seen. This device is distinguished from that of Figures 1A and 1B, in that the first and second conductive elements are each covered with a dielectric element.

The device of FIGS. 2A and 2B comprise a first set E1 and a second set E2 '. Each set comprises a first conductive element 2 and a second conductive element 4 arranged vis-a-vis at a distance that can vary under the influence of an external event. In the example shown, only the second conductive element is movable along an axis Z.

The first conductive element 2 and the second conductive element 4 are covered respectively with a first 6 and a second dielectric element. The first and second dielectric elements are then arranged vis-a-vis.

The materials of the first 6 and second 10 dielectric elements are chosen such that they have different triboelectric affinities. One of the materials tends to give away electrons while the other material tends to capture electrons. In the example shown, it is the material of the second dielectric element 10 which tends to pick up electrons and the material of the first dielectric element 6 which tends to give up electrons. The presence and absence of charges (electrons) are symbolized by signs - and + in FIGS. 2A and 2B. For example, the first dielectric element is Teflon and the second dielectric element is nylon or wool.

The first 2 and the second 4 conductive elements are electrically connected by an electrical consumption circuit 8.

A capacity capacitor C1 is then formed between the first conductive element 2 and the first dielectric element 6, a capacity capacitor C2 is formed between the second conductive element 4 and the second dielectric element 10, and capacitor capacitor C3 is formed between the first 6 and second 10 dielectric elements.

In this embodiment, the second assembly E2 'is movable relative to the first assembly E1. The movable assembly of the second assembly E2' is such that the displacement is sufficient to allow the first 6 and second 10 dielectric elements to come into contact with each other. , allowing an exchange of electrons.

As described for the embodiment of FIGS. 1A and 1B, the first dielectric element 6 and / or the second dielectric element 10 may or may be previously loaded.

We will now explain the operation of this device.

The displacement of the second set E2 'with respect to the first set El generates a variation of capacitance C3 between the charges stored on each of the dielectric elements 6, 10. When the two sets E1, E2' are distant, each set E1, E2 'has tendency to become neutral, the capacities C1 and C2 are much superior to the capacity C3. When the sets E1, E2 'come closer, they are under the influence of each other and tend to equilibrate each other. The charges stored in the conductive elements are then partially removed to balance, the excess of electrons of one of the conductors will then fill the electron deficiency of the other conductor via a flow of current through the circuit 8 . Whenever the dielectric elements 6, 10 come into contact, electrons are torn off from the first dielectric element 6 and are picked up by the second dielectric element 10.

This embodiment has the advantage of offering a greater choice of material couples with different triboelectric affinities for producing the dielectric elements, one could for example choose the nylon for the first dielectric element and the polypropylene for the second dielectric element.

FIG. 3 shows another example of a recovery device according to the first embodiment, in which the first and second sets, instead of being in the form of a plate facing each other, are each formed by a plurality of wires.

Each set comprises a plurality of wires 100, each wire 100 of the first set comprises a core 102 made of electrically conductive material and a casing made of dielectric material 106, and each wire of the second set comprises a core 104 made of electrically conductive material and a casing of material dielectric 110.

The wires of each set are arranged side by side and the conductive cores are electrically connected together in series or in parallel. In the representation, the wires are arranged parallel to one another, but an embodiment in which the wires are not arranged in a strictly parallel manner does not depart from the scope of the present invention.

As in the device of Figures 2A and 2B, the shell materials of each set are chosen such that they have different triboelectric affinities.

Capacity capacitors C1 and C2 are formed between the cores 102 and the envelopes 106 and the cores 104 and the envelopes 110 of the wires of the first and second assemblies, respectively, and a capacitor C3 is formed between the envelopes 106 and 110 of the first and second second sets.

The operation of this device is similar to that of the device of Figures 2A and 2B. This device is particularly suitable for producing fabric. Indeed we can consider weaving the son 100. For example, the son 100 form the weft son and son conventional, for example cotton, form the warp son. The diameter of the conductor wire may be between 10 μιη and 300 μιη. The thickness of the dielectric envelope may be between 10 nm and 1 mm.

It is also possible to envisage a textile structure woven from yarns as described above, to make a garment such as a sweater, a shirt, jeans, etc. In the case of a thick fabric, for example of greater thickness at 3 mm, it is possible to use these son only to achieve the layer of the textile that comes into contact with the second set to maximize the capacity.

The embodiment of textile directly with these threads has the advantage over a textile formed of a sheet of conductive material deposited on a rear face of a conventional fabric, the thickness of which is of the order of 1 mm, d have the electrical conductors located much closer to the friction zone which are electrically charged, and thus obtain an electrical capacitance vis-à-vis these higher loads.

A device comprising a set of wires as described above and a plate assembly as described in connection with FIGS. 1A, 1B or 2A and 2B are not outside the scope of the present invention.

In Figure 4, there is shown an example of a device according to a second embodiment, wherein the two sets vis-à-vis are not electrically connected.

The device of FIG. 4 comprises two sets movable with respect to each other, for example at a distance along the axis Z.

The first set comprises two conductive elements 202, 202 'isolated from each other and each covered by a dielectric element 206, 206'. The two conductive elements 202, 202 'covered with a dielectric element 206, 206' are arranged next to each other and are integral with each other.

The second set comprises two conductive elements 204, 204 'isolated from each other and each covered by a dielectric element 210, 210'. Both conductive elements 204, 204 'covered with a dielectric element 210, 210' are arranged next to each other and are integral with one another.

The materials of the dielectric elements of the same set are chosen such that they have different triboelectric affinities.

The two sets are arranged facing each other so that a dielectric element 206, 206 'is substantially opposite a dielectric element 210, 210' respectively.

In addition, the materials of the dielectric elements facing each other of the two sets are chosen so that they have different triboelectric affinities. For example, the same dielectric material for the elements 206, 210 'and the same dielectric material for the elements 206', 210 can be chosen.

The two conductive elements 202, 202 'and 204, 204' of each set are electrically connected through a consumer circuit 208, 208 '

The operation of this device is similar to that of the device of Figures 2A and 2B, except that the current does not flow between the two conductive elements movable relative to each other.

The number of conductive elements and dielectric elements is not limited to two and may be greater than two.

Alternatively, it is conceivable to recover the energy on only one of the two sets, for that the conductive elements of the other set would be short-circuited. The energy recovered on a set is equal to the energy that is recovered in the configuration of FIG. 4. The integration of this device can be further improved, by producing structures in the form of wires, as in the example of FIG. figure 3.

In Figure 5, we can see another embodiment of the second embodiment, comprising only a first set similar to the sets of the device of Figure 4, which is arranged vis-à-vis a third conductive element 212 having a triboelectric affinity between those of the two dielectric elements 206, 206 '. If we denote by Al the triboelectric affinity of the dielectric element 206, A2 the triboelectric affinity of the third conductive element 212 and A3 the triboelectric affinity of the dielectric element 206 '. The triboelectric affinity values are as follows:

A1> A2> A3 or AKA2 <A3

That is, when the third conductive element 212 contacts the dielectric elements 206, 206 ', it transfers electrons to the affinity dielectric element 206 and collects electrons from the affinity dielectric element A3. . These states of charge are symbolized by the signs - and +. Thus the two insulating elements 206, 206 'are of opposite charges, which implies that the conductive elements 202, 202' are influenced by opposite charges allowing the circulation of electrons when the third conductive element 212 moves relative to the first set and that the circuit is closed by a load 8, as will be described below.

Alternatively, it may be provided to cover the conductive element 212 with a dielectric element which will have the triboelectric affinity between those elements 206, 206 '.

The energy is recovered on the first set.

The operation is similar to that of FIG. 4. When the conductive element 212 is remote from the first assembly, each dielectric element 206, 206 'equilibrates with the conductive element which carries it. When the third conductive element 212 approaches, the dielectric elements 206, 206 'and the conductive element 212 influence each other. The transfer of electrons to balance the two conductive elements 202, 202 'takes place between the two conductive elements 202, 202' via the electrical power consumption circuit 208. Energy is then harvested from the first set.

In Figure 6, we can see an embodiment wherein the first set comprises more than two conductive elements and more than two insulating elements. I l comprises alternating dielectric elements 206, 206 'having triboelectric affinities A1 and A3. In the example shown, all the conductive elements 202 carrying a dielectric element 206 of affinity Al are connected together and all conductive elements 202 'carrying a dielectric element 206' of affinity A3 are connected together. The circuit 208 connects the conductive elements 202, 202 '. As an alternative, it is conceivable to connect a conductive element 202 to a conductive element 202 'individually through a circuit.

This second embodiment is particularly interesting for example for an application in the textile field, since it avoids the use of long length son, the energy being recovered between two close electrodes. For example, in the case of an integration of the device of Figure 4 in a sweater, the first set may be in one sleeve and the second set 2 may be placed on the body of the sweater in front of the first set placed in the sleeve. . It is no longer necessary to pass a long wire between the two elements. Its integration is optimized.

In Figure 7, we can see an embodiment for recovering the energy of relative movements both along the X axis and along the Z axis.

The first assembly comprises an insulating support 300 on which are formed discrete conductive elements covered with a dielectric element 306 and the second assembly comprises an insulating support 300 'on which are formed discrete conductive elements 304. The displacement along the X axis ensures a capacitance variation of the capacitors formed by the conductive elements 302, 304 facing the fact of the variation of facing surface. The variation of overlap is significant ensuring a significant variation of capacity. Preferably, the variation of overlap between the two sets is at least 20%, so as to cause a variation in capacity of at least 20%, even more advantageously at least 40% so as to cause a capacity variation of at least 40% advantageously.

The energy is recovered between the conductive elements 302 and the conductive elements 304. For this, all the discrete conductive elements 302 may be connected together and all the discrete conductive elements 304 may be connected together, or each or more conductive elements may or may be connected to one or more conductive elements 304 respectively through a circuit. It can be envisaged that the conductive elements 304 permanently rub on the dielectric elements 306 ensuring a recharge of these dielectric elements or that the contact is random.

Advantageously, the facing surfaces of these sets are flat, the conductive elements and the dielectric elements flush with the surfaces, which facilitates friction.

It is conceivable to make conductive elements whose shape allows a recovery of energy along three axes, the X, Z axes and a third axis perpendicular to the X and Z axes. In FIG. 12, a recovery device can be seen in FIG. wherein the materials forming the dielectric element (s) 906, 910 exhibit compressibility properties along the Z axis. The two dielectric elements 906, 910 are carried by conductive elements 902, 904 and are in permanent contact. The capacitance variation results from the compression of the dielectric elements due to a movement along the Z axis, and the recharge of the dielectric elements is obtained by a friction in the XY plane. This device is particularly suitable for application in clothing, for example in linings or in shoes, for example between the insole attached to the inside of the shoe and the inside of the shoe.

In Figures 8 to 11, we can see other embodiments of a recovery device in which the two sets have a relative rotational movement.

In FIG. 8, the first assembly forms a stator comprising an electrical insulating support 400, a conductive element 402 partially covered by a dielectric element 406. The second assembly forms a rotor that is rotatable about an axis Z, and comprises an insulating support 400 'and a conductive element 404. The rotor is not parallel to the stator and is in contact therewith at an edge 411 so as to ensure contact / friction between the conductive element of the rotor and one of the dielectric elements to recharge them. The conductive member 404 of the rotor and the dielectric member 406 have different triboelectric affinities. The conductive elements 402, 404 are connected by an electrical circuit 408. As the rotor rotates, the capacitances of the capacitors formed between the conductive member 404 and the dielectric member 406 vary. An electron flow takes place between the two conductive elements 402, 404 through the electrical circuit 408.

In FIG. 9, it is possible to see, seen from above, a stator in which the opposite face of the rotor is cut into four quarters, two non-successive quarters being covered with dielectric elements 406, the other quarters being formed by the element driver 402.

It will be understood that the stator and rotor structures can be exchanged.

In Figures 10 to 12, we can see another embodiment of rotating device. In this example, the rotor is parallel to the stator. The rotor is similar to the rotor of FIG. 8. The stator comprises, for example, an angular zone ZI of 180 ° in conductive element 502 covered by a dielectric element 506 in contact with the conductive element of rotor 504 and an angular zone Z2 of 180 ° not covered with a dielectric element and whose thickness of the conductive element may be smaller than that of the conductive element of the zone ZI. Thus, when rotating the rotor, the conductive member 504 contacts the dielectric member 506 on one half-disk surface, the capacity is maximum and the capacity is minimal on the other half-disk. In addition, the charging of the dielectric element 506 takes place at the friction zone.

In FIG. 11, another example of a rotary recovery device comprising an eccentric rotor can be seen. The rotor which forms the second conductive element 604 is in the example shown in the form of quarter disc, it then has a center of gravity eccentric with respect to the axis of rotation. The stator comprises a disk-like conductive element 602 of which two areas of a quarter disc each are covered by a dielectric element 606, the rotor is in contact with the dielectric elements 606, which ensures their charging.

A rotating recovery device in which the rotor would also include one or more dielectric elements is not beyond the scope of the present invention. The output voltage of the recovery device is alternative, it is generally high, for example several tens or even hundreds of volts and the extractable current is low of the order of 1 μΑ. In order to be able to be used by an electronic circuit, the electrical energy at the output of the energy recovery system is converted into a lower voltage, for example less than 10 V, for example 3 V.

For example, it is possible to use an inductive converter, of the Flyback type, for example. It is capable, on a maximum (in absolute value) of voltage across the device, to transfer the electrical energy stored on the latter to energy storage means, such as a capacity, a battery or other serving as an energy buffer between the power generation device and the energy consuming circuit, this storage can in particular serve to stabilize the output voltage. In order to use the energy recovered by the energy recovery system for an application, one can imagine an intermittent operating mode with storage in a buffer. For example, the storage means accumulate energy until its stored energy level is sufficient to wake up an electronic circuit, give it time to perform a number of operations and put it back into standby.

The invention could then be applied to the supply of communicating sensors capable of measuring, processing and transmitting wirelessly to a receiver. For example, it would be possible to measure a physical parameter, process it and send it by radio as soon as the level of energy stored in the storage means reaches a certain threshold. If the storage is of capacitive type, its voltage evolves according to its state of charge, in this case, or one oversizes the capacity so that the measurement / treatment / transmission generates only a small drop of tension, leaving the latter in the possible operating range of the electronics, or an additional converter is placed at the output of the storage element to supply the electronics with a well stabilized voltage when it is not in standby. With regard to the supply of the management electronics which detects the maximum voltage (in absolute value) at the terminals of the electrostatic structure and which generates the signals of control of the transistors of the converter (s), it can be formed initially directly by the output of the energy recovery device via a rectifier bridge and a regulator and then as soon as the voltage across the storage element is sufficient, by the storage means.

Furthermore, the energy recovery devices have a low capacitance value, requiring a high value inductance and with a very low parasitic capacitance for carrying out the energy transfer from the recovery device to the storage means. If the capacity of the recovery device is resonated with an inductance over a quarter of resonance period to transfer the energy of this capacitance to the magnetic circuit of the inductor, then the magnetic circuit sees a variation of flux at the frequency of 1 / (2nV (LC)) which can be high if the capacitance is very low (<10 pF), which is a source of losses in the magnetic core and high currents in the inductance and in the electronic control switches, such as transistors, diodes. Advantageously, there is provided a system comprising several recovery devices according to the invention placed in parallel, the devices being such that the appearance of the maximum and minimum capacitances between their conducting elements are relatively synchronized. The system then has a higher capacity value, thus limiting the energy losses during the transfer between the device and the storage means.

We will now describe an application of the device of the figures

1A and 1B to energy recovery in a motor vehicle tire. The devices of Figures 2 to 7 could be similarly applied.

The energy recovery of the rotation of a tire uses the variations of accelerations in the tire, in FIG. 13, we can see a schematic representation of a tire P on a road R on which are marked the different zones of the tire. acceleration on the tire P, and in FIG. 14, the radial acceleration in m can be graphically represented. s ^"2 of a point on the running surface of the tire as a function of time.

It can be seen that, during rolling, there are fairly abrupt variations of radial acceleration at _r within the tire, in particular between the radial acceleration present in the part of the tire that is not in contact with the road and the radial acceleration

almost zero in the part in contact with the road between points PI and P2.

The energy recovery device such as that of FIG. 1A is fixed on the inner part of the tread of the tire by its first conductive element 2. A mass is fixed on the second assembly so as to increase its sensitivity to the centrifugal acceleration and therefore increase the power output of the energy recovery system. The device moves with the tire and undergoes variations of accelerations. The rapid acceleration variations create the shock equivalent of the mass-spring structure (the second conductive element 704 behaves like a mechanical spring) which vibrates at its resonant frequency after going one or more times in abutment. The presence of the charges in the dielectric element 6 is then ensured by an intermittent contact between the dielectric element 6 and the second conductive element 704.

This energy recovery device has a reduced cost compared to existing, since it does not use expensive materials such as permanent magnets, copper or piezoelectric materials.

Moreover, since mechanical contacts are allowed between the two parts of the electrostatic structure, the variations in electrical capacitance are maximized and consequently the electrical energy produced per cycle is maximized.

In addition, the energy can be recovered regardless of the running speed, unlike known devices which are made rigidly to avoid contact between the two parts, which prevents energy recovery at low speed.

Advantageously, the electrical energy thus generated can be used to supply sensors arranged in the tires, for example pressure sensors.

The tire could be equipped with several recovery devices regularly distributed in the tire. Very advantageously, it is possible from the characteristics of the current and the voltage recovered to obtain information on the running.

FIG. 15 shows the variation of the electric current i in μΑ recovered in a tire with a device of FIGS. 1A and 1B according to the invention as a function of time t in seconds.

The information that can be obtained on the running is for example the length of the contact zone by measuring the time elapsed between two close shocks designated te in FIG. 15, ie the time elapsed between the contacting and the output of the contact of a point of the tire with the road, the speed of rotation from the frequency of the shocks "distant", spaced in the time designated by tl.

One can even consider obtaining pressure measurements from the frequency and the decay rate of the impulse response designated by Ri. Indeed, the greater the pressure, the greater the damping of the vibrating structure and the higher its oscillation frequency is high. By measuring the oscillation frequency, we can deduce the pressure.

In Figures 16, 17, 18A and 18B, there can be seen several embodiments of device structures allowing the approximation and removal of the two sets of the device, particularly suitable for implementation in a tire. It will be understood that these different structures can be applied in all areas and any system capable of moving at least one of the conductive elements.

In FIG. 16, the device comprises a rigid support 16 between the first conductive element 2 and the second conductive element 704. A mass 14 is integral with the second conductive element 704. The second conductive element 704 is made in such a way that deforms under the action of radial acceleration when the area of the tread to which it is attached is not in contact with the road. By deforming (the profile of the second conductive element 704 during its deflection is shown in dashed line), the second conductive element 704 approaches the dielectric element 6. It then resumes its place or starts to vibrate at its resonant frequency when the tread area comes in contact with the road. The second conductive member 704 moves toward and away from the dielectric member 6, which generates an electron flow in the circuit 8. The second conductive member 704 randomly contacts the dielectric member 6 and the recharge.

FIG. 17 shows another embodiment, in which the support 18 between the first 2 and the second conductive element 4 is flexible and it is its deformation under the effect of the centrifugal force which allows the connection between the dielectric element 6 and the second conductive element 4. A mass 14 is integral with the second conductive element 4. The support 18 has elastic properties to ensure the return to the rest position of the device in the absence of a centrifugal force , ie when the area to which the device is attached is in contact with the road.

This device has the advantage of being able to use rigid conductive elements in parallel movement, which maximizes the variation of capacity. Indeed, the moving facing surfaces relative to each other are constant during movement, unlike the device of Figure 16 wherein the facing surfaces decrease when the second conductive member 704 is deformed.

In Figures 18A and 18B, another example of structure can be seen. In this example, the first element 802 has a curved profile which follows the shape of the tire P and is relatively flexible to follow the deformation of the tread. As for the second conductive element 4, it is rigid and plane. As a variant, the second conductive element 4 is flexible and deforms like the first element 802 in the presence of centrifugal accelerations, the first element 802 itself being able to be flexible and to follow the shape of the tire.

When the zone to which the device is fixed is not in contact with the road, the first conductive element 802 has its curved profile, the second conductive element 4 is therefore separated from the dielectric element 806 (FIG. 18A). When the zone to which the device is fastened comes into contact with the road, the tread deforms to flatten, which has the effect of making substantially flat the first conductive element 802 which comes into contact with the second conductive element 4 via the dielectric element 806 (FIG. 18B). The capacity is maximum when the area to which the device is attached is in contact with the road, unlike the devices of Figures 16 and 17.

In the embodiment variant where the second conductive element 4 is also flexible, it conforms to the tire surface in the presence of centrifugal acceleration and returns to its original shape in the zone of contact with the road which corresponds to its state of rest. In addition, the second conductive element 4 can be in a domed state of rest so as to be further away from the first conductive element 802 in a state of rest even if the first conductive element 802 tends to flatten in the contact zone with the road .

It will be understood that the different structures of FIGS. 16 to 18 could be combined: for example a flexible support such as that of FIG. 17 could be associated with a flexible conductive element.

For example, the device can be glued inside the air chamber or directly integrated into the tread of the tire. Radial acceleration will tend to hold it in place by projecting it outward.

As already described above, the device according to the present invention can be applied to the textile industry and be integrated with clothing to recover energy from the relative movements of a person's limbs, for example movements between the two legs, between the arms and the trunk, and whose parts of clothing which they are covered rub one against the other. According to the invention, this friction is used to recharge the dielectric elements.

For example, it is possible to recover the energy of the relative displacement of the legs which move away and approach regularly during the walk thanks to pants equipped with a recovery device according to the invention. FIG. 19 schematically shows a trouser P provided with a recovery device according to the invention which is that of FIG. 2A, but this is in no way limiting. The pants are reproduced in dotted lines, it is understood that the device is not to scale. The pants may comprise a leg with a first conductive element covered with a textile fabric forming the dielectric element and a leg whose outer surface is conductive forming the second conductive element.

Alternatively, the trousers may comprise a leg with a first conductive element covered with a high electron affinity textile fabric forming a dielectric element and a leg with a second conductive element covered with an electron donor textile fabric forming a other dielectric element. In this configuration, the friction and of textiles with different triboelectric affinities favor the transfer and therefore the accumulation of excess or deficiency of electrons on each of the legs. Several recovery devices can be equipped with the same garment.

As already described in the context of the second embodiment, the implementation of conducting son with a dielectric material envelope allows to bring the conductive elements of the friction zone which is electrically charged and thus allows to obtain a electrical capacity with respect to these higher loads. Moreover, the conductive elements being completely isolated, this embodiment makes it possible to protect the user from direct contacts with them when they are loaded.

Similarly to the application examples for energy recovery in a tire, it is possible to develop structures with different geometries and using the same conversion principle.

In addition, as in the case of the application to the tire, it is possible to collect information on the movement of the person wearing the garment. For example, it is possible to count the steps or the distance between the steps, for example by placing the device at the level of the leg, or to measure the physical activity of a person, for example to determine the loss of autonomy or not of an elderly person.

The energy recovery device can also be applied to various existing devices for daily use which maximizes the energy collected. For example, the device can be integrated into the pages of a notebook or a book. For example, some sheets would contain in their thickness a conductive plane element and others would be conductive on the surface or would be made of another dielectric material with a triboelectric affinity different from that of the paper pages, for example Teflon, PVDF ... and also containing a plane conductive element in their thickness.

Alternatively, the pages of the notebook would all be paper and the front or back of each page would be conductive. For example, an aluminum layer would be deposited on the back of each page. The energy recovery can then be done between the conductive zones of the pages which follow each other, since the aluminum tends to yield loads and the paper tends to pick up loads.

We will now give a numerical example in the case of the application of the invention to a sweater shown in Figure 20.

It is possible to manufacture simple devices comprising two aluminum plates or films and a Teflon film.

This device is set up in a sweater in an area located at the ribs of the person wearing the sweater so as to use the friction between the body of the sweater and the sleeves.

As a first approximation, the output power of this system is equal to P = V ² .dC / dt where V is the surface potential of the electret and dC / dt is the capacity variation of the structure, ie the capacity variation between the two conductive electrodes.

In Figure 20, we can see the device applied to the sweater in side view and in front view

In the example shown, the capacity variation is obtained by a surface variation by lateral displacement of surfaces due to the swinging of the arms relative to the body.

Consider that the electret has a thickness d equal to ΙΟΟμιη, a dielectric constant of 2 (case of teflon) and a surface potential of 1000 V. The conductive element 4 and the dielectric element 6 have a common surface S which depends on the position of the sleeve relative to the body of the sweater and which will vary for example when walking.

Thus: C = ee ₀ S / d and dC / dt = (ee ₀ / d) x (dS / dt)

Assuming that the device has a surface area of 1 cm ² and the frequency of swinging movement of the arms back and forth is 1 Hz, the output power is:

P = 17.68 μνν / cm ² .

If we take a device whose surface is 1 dm ² we can recover a power 100 times higher, namely 1.7 mW.

The same power generated will be substantially the same if one considers the mode of operation with movements of contacting and removal, for example by spacing and lateral approximation of the arms of the body.

We will now describe examples of a method of producing a tire provided with the recovery device.

Thanks to the invention, we can develop very simple energy recovery structures applied to the tire.

In a first step, a first set is made by depositing an aluminum layer on a Teflon film. The aluminum layer forms the first conductive element and the teflon film forms the first dielectric element.

In a next step, the aluminum-coated teflon film is placed in a plastic material frame, which allows the film to be held in place and to make contact with the metallization of the Teflon film, the frame being provided with of suitable electrical contacts.

In a subsequent step, an aluminum sheet forming the second conductive element of the second assembly is disposed in the frame and is positioned above the Teflon film whose aluminum-coated face is the rear face, so that arrange an air gap between the Teflon and the aluminum foil.

In a next step, a mass is adhered to the aluminum foil. The first and second conductive elements are then connected to an electronic circuit.

Finally, the complete system is encapsulated and integrated into the tire.

We will now describe two examples of a method of producing a textile object. As in the case of the tire, it is possible to develop very simple energy recovery structures.

The production method according to a first exemplary embodiment comprises a step of manufacturing a Teflon-coated conductive sheet forming a first assembly.

Then, the sheet thus produced is integrated on the body of the sweater in an area in front of the sleeves.

In another step, it incorporates another conductive sheet in the sleeve of the sweater forming a second set, in front of the teflon-coated sheet embedded in the body of the sweater.

Finally, the two conductive sheets are connected to an electronic circuit that exploits the electrical energy produced.

The production method according to a second embodiment comprises a step of manufacturing teflon-wrapped copper wires forming a first set, and manufacturing of nylon-wrapped copper wires forming a second set.

In a next step, the integration of copper son surrounded Teflon in the body of the sweater in an area located in front of the sleeves.

In a next step, the integration of the nylon-wrapped copper wires into the sleeve of the sweater, in front of son surrounded Teflon.

Finally, the copper wires of the two sets are connected to an electronic circuit which exploits the electrical energy produced during the movements of the person wearing the sweater.

Claims

1. A method of energy recovery by means of an energy recovery device comprising a first and a second set placed vis-à-vis and movable relative to each other, the first set comprising the at least one first conductive element (2, 102, 302, 402) and a first dielectric element (6, 106, 306, 406, 506) carried by the first conductive element (2, 102, 302, 402, 802), and the second assembly comprising at least one second conductive element (4, 104, 304, 404, 504), said first dielectric element (6, 106, 306, 306 ', 406, 506) being arranged between the first (2, 102, 302) 402) and the second (4, 104, 304, 404) conductive member, said first dielectric member (6, 106, 306, 306 ', 406) being engagable with a portion of the second set and wherein the first dielectric element (6, 106, 306, 306 ', 406) and the material of the part of the second set with which the first The dielectric element in contact has different triboelectric affinities, the method having the following steps:

2. The recovery method according to claim 1, wherein said capacitance variation between the first dielectric element and the second conductive element during said displacement is at least 20% of the capacitance value in the so-called contact position.

3. The recovery method according to claim 2, wherein said capacitance variation between the first dielectric element and the second conductive element during said displacement is at least equal to 40% of the capacitance value in the so-called contact position.

4. A recovery method according to claim 1, 2 or 3, wherein in the contact position, a first equilibrium state appears between the first conductor, the first dielectric element and the second conductive element, and in the remote position, a second state of equilibrium appears between the first dielectric element and the first conductive element, the transition from the first equilibrium state to the other causing the circulation of an electric current between the first conductive element of the first assembly and the electrical circuit

5. Energy recovery device comprising a first and second set placed vis-à-vis and movable relative to each other, the first set comprising at least a first conductive element (2, 102, 302 , 402) and a first dielectric element (6, 106, 306, 406, 506) carried by the first conductive element (2, 102, 302, 402, 802), and the second assembly comprising at least a second conductive element (4 , 104, 304, 404, 504), said first dielectric element (6, 106, 306, 306 ', 406, 506) being disposed between the first (2, 102, 302, 402) and the second (4, 104, 304, 404), said first dielectric member (6, 106, 306, 306 ', 406) being engageable with a portion of the second set and wherein the material of the first dielectric member (6, 106, 306, 306 ', 406) and the material of the portion of the second set with which the first dielectric member contacts have different triboelectric affinities, the first dielectric member of the first together being able to present a charge obtained in whole or in part by a triboelectric effect when the first dielectric element is brought into contact with an element of the second assembly called a contact element, the device allowing relative displacement of the first and second sets between a first position, said contact, for which the first preloaded dielectric element is in contact with said contact element of the second set and has a first contact surface and a second position, said remote, for which said contact element of the second set is far from the first dielectric element that they are no longer in contact or that they have a second lower contact surface to said first contact surface, this displacement inducing a capacitance variation between the first dielectric element and the second conductive element, the device comprising in addition, an electrical circuit connected to the first conductive element so that an electric current is able to circulate, during said displacement, between the first conductive element of the first assembly and the electrical circuit, this current being induced by said relative displacement of the first and second sets and inducing electrical energy in the electrical circuit.

6. Recovery device according to claim 5, wherein the electrical circuit connects the first conductive element and the second conductive element.

7. Energy recovery device according to claim 6, wherein the second conductive element (4) forms the part of the second assembly with which the first dielectric element (6) comes into contact.

8. Energy recovery device according to claim 6, wherein the second set comprises a second dielectric element (10, 110) carried by the second conductive element (4, 104), and disposed between the first dielectric element (6, 106) and the second conductive element (4, 104), the second dielectric element (10, 110) forming the part with which the first dielectric element (6, 106) comes into contact.

9. Energy recovery device according to claim 5, comprising a first and a second set vis-à-vis, wherein the first set comprises at least one pair of adjacent conductive elements (202, 202 ') each covered by a dielectric element (206, 206 '), the two dielectric elements (206, 206') having different triboelectric affinities, and the second set comprising at least a second conductive element (212) having a triboelectric affinity classified between the triboelectric affinities two dielectric elements (206, 206 ') of the first set, wherein the electrical circuit connecting the at least two conductive elements (202, 202') of the first set.

The energy recovery device according to claim 9, wherein the second set is formed by a conductive element (212) covered with a dielectric element.

The energy recovery device according to claim 9, wherein each of the first and second sets comprises at least one pair of two adjacent conductive elements (202, 202 ', 204, 204') each covered by a dielectric element (206). , 206 ', 210, 210'), the two dielectric elements (206, 206 ', 210, 210) of each pair having different triboelectric affinities, and the dielectric elements (206, 210, 206', 210 ') facing each other. with different triboelectric affinities, and wherein the electrical circuit is connected between the conductive elements of each pair.

The energy recovery device according to claim 9, wherein each of the first and second sets comprises at least one pair of two adjacent conductive elements (202, 202 ', 204, 204') each covered by a dielectric element (206). , 206 ', 210, 210'), the two dielectric elements (206, 206 ', 210, 210') of each pair having different triboelectric affinities, and the dielectric elements (206, 210, 206 ', 210') in vis-à-vis having different triboelectric affinities, the conductive elements of the second set being short-circuited.

13. Energy recovery device according to one of claims 5 to 12, wherein the first and second sets are planar and are parallel, at least one of the first and second sets being mounted on a frame so as to move at least perpendicular to the other driver assembly.

14. Recovery device according to one of claims 5 to 12, wherein the first and second sets are planar and are parallel and wherein the first set is structured and the second set is structured so that, during a displacement of the first and / or second set in a direction parallel to the first and second sets, a capacitance variation occurs between the one or more dielectric elements (306) of the first set and the second set.

15. Energy recovery device according to one of claims 5 to 12, wherein the first and / or second set comprises a plurality of son (100) each comprising a core (102, 104) and a casing (106). , 110), the core (102, 104) forming a conductive element and the envelope (106, 110) forming a dielectric element.

The energy recovery device of claim 15, wherein the yarns (100) are woven.

17. Energy recovery device according to one of claims 5 to 16, wherein at least the second assembly is flexible so as to approach the first set under the effect of an external force and to come into contact with the first element when said external force has a sufficient intensity.

18. Energy recovery device according to one of claims 5 to 17, wherein the first and the second set are held by a support (18), said support (18) being such that it deforms elastically to bring closer the first assembly and the second assembly under the effect of an external force and to put them in contact when said external force has a sufficient intensity.

19. Energy recovery device according to one of claims 5 to 18, wherein the first set has a curved shape in the absence of application of an external force and is away from the second set, said first set being deformed by application of an external force and coming into contact with the second set.

20. Energy recovery device according to one of claims 5 to 16, wherein the two sets are in permanent contact.

21. Energy recovery device according to one of claims 5 to 20, wherein the one or more dielectric elements (906, 910) are compressible.

22. Energy recovery device according to one of claims 5 to 21, wherein at least one of the sets has a rotational movement about an axis of rotation.

23. An energy recovery device according to claim 22, wherein the first and second sets are disc-shaped, at least one of the sets being rotatable about its axis, the axes of the first and second sets being second sets being intersecting, the two sets being in permanent contact by their edges, the disk of the first set being divided into angular sectors, angular sectors being covered by the first dielectric element (406) and angular sectors not being covered by of the first dielectric element.

24. An energy recovery device according to claim 22, wherein the first and second sets are parallel, the first set having the shape of a disk and being divided into angular sectors, first angular sectors being covered by the first element. dielectric (406) and second angular sectors being or not being covered by the first dielectric element, the first angular sectors being in permanent contact with the second assembly.

25. Energy recovery device according to claim 24, wherein the second set is in the form of a disk, the axes of the disks being merged with the axis of rotation.

26. Energy recovery device according to claim 22, wherein the second set is rotating and has the shape of an angular sector rotatable about the rotation axis.

27. Energy recovery device according to claim 6, wherein the first dielectric element (6) is Teflon and the second conductive element (4) is aluminum.

The energy recovery device of claim 7, wherein the first dielectric member (6) is Teflon and the second dielectric member (10) is nylon or wool.

29. System comprising at least two energy recovery devices according to one of claims 5 to 28 connected in parallel or series.

30. System comprising at least one energy recovery device according to one of claims 5 to 28 and storage means of the recovered energy before its transfer to the use circuit.

31. The system of claim 29 or 30, comprising at least one communicating sensor capable of measuring, processing and transmitting by radio means to a receiver as soon as the amount of energy stored in the storage means is above a given threshold.

32. Garment comprising at least one device according to one of claims 5 to 28 or a system according to claim 29, 30 or 31, the first set and the second set being carried by two parts of the garment vis-à-vis and intended to move relative to each other and to come into contact, for example these two parts being formed by two legs of pants (20).

33. Garment according to claim 32, comprising means for processing the variation of the current or of the electrical voltage recovered as a function of time in order to determine information on the relative displacement of the parts of the garment.

34. Tire for a motor vehicle comprising at least one recovery device according to one of claims 1 to 28 or a system according to claim 29, 30 or 31, one of the sets of the device being fixed on an inner face of a tread of the tire.

Tire according to claim 34, comprising means for processing the variation of the current or of the electrical voltage recovered as a function of time in order to determine information on the tire, such as the speed of rotation, the pressure, the temperature or the temperature. 'acceleration.