DE102014008991A1 - By a force held conductive liquid drop in an energy converter - Google Patents

Abstract

Conductive fluid drop held in a Krupenkin variable capacitor.

Description

1. State of the art

Are known polymers in which z. As ferromagnetic powders are dispersed, wherein the polymers are preferably present as a curable liquid, and can be printed on a surface.

The patents US7898096 . US2012 / 0181901 (Krupenkin et al.) Describe a capacitive transducer for converting mechanical to electrical energy, wherein the applied force changes the geometry and thus the capacitance of one or more capacitors such that they can discharge a charge which is dissipated by means of an electronic circuit and is buffered in an energy storage. For this purpose, such a capacitor preferably has a first fixed, planar and conductive electrode and a low-surface-energy dielectric applied thereto; the latter is contacted by an opposite liquid, also conductive electrode, the z. G. Galinstan (a gallium compound), which gallstone has a high surface energy and thus tends to dissolve from the aforementioned dielectric. Now, this capacitor is deformable, so that the second capacitor electrode opposite the first electrode has a variable contact area, such that the capacitance of the capacitor varies from low to high. In another claimed variant, the liquid second electrode moves sideways, which also leads to a change in the Kondansatorkapazität and is available for energy recovery. The prior art set forth in the above two patents is hereinafter referred to as "Krupenkin", and is, for. B. the font DE 10 2012 019 511_7 which describes the placement of such capacitors in a deformable box.

According to Krupenkin, capacitive Galinstan transducers now have a serious practical defect: on the one hand, galinstan oxidizes in air almost immediately and becomes useless as a conductor; On the other hand, a deformable capacitor according to Krupenkin and according to the current state of the art is not completely gas-tight buildable, so that any inert gas would escape.

Now Krupenkin also claims other conductive liquids; on the one hand, however, there are no metals at room temperature except galinstan or gallium or its eutectics, which also oxidize, or the mercury prohibited in a consumer application; On the other hand, the known non-metallic conductive liquids have a much lower surface energy than a metal. Now Krupenkin does not teach how to make such liquids as part of a condenser to form a convex drop, which can cling to a pressed-dielectric and reliably dissolve again. Another unsolved problem in Krupenkin involves sticking this drop of liquid to an electrode - that is, the uninterrupted electrical contact of an electrical supply line to the second capacitor electrode.

What is needed is a conductive liquid which is kept permanently as drops on a conductive - preferably formed of metal - electrical supply line, and which preferably forms a reversibly compressible electrode in a Krupenkin capacitor. Ie. that a droplet once pressed together, when this capacitor is stretched again perpendicular to the first electrode, assumes its original shape again, and thus can be used in a capacitor according to Krupenkin.

2. Description of the invention

The invention described below solves the above problem with a liquid according to claim 1. Further characteristics of the invention are laid down in the dependent claims.

2.1 Description of a preferred embodiment

Preferably, the conductive liquid to form a second capacitor electrode is an ionic liquid - that is, a liquid at room temperature, conductive salt - in which ferromagnetic particles have been introduced; such a liquid has properties of a ferrofluid and is henceforth referred to. Does such a ferrofluid now z. B. on a metallic conductive ferromagnet, it assumes a predetermined by the magnetic field lines shape, preferably that of a single drop. Now, a Krupenkin variable capacitor, which firstly uses the above-mentioned magnet as a conductive supply to the second electrode and, secondly, a drop of such a conductive ferrofluid as a liquid second electrode, can be constructed. It is preferably assumed that, in addition to the said ferromagnet and said drop, all other elements in said capacitor are diamagnetic.

Now ionic liquids as well as the ferrofluids formed from them have a negligible vapor pressure and are stable in preferred embodiments in air. So you do not have to build the inventive capacitor airtight.

2.2 Further embodiments of the invention

Conceivable are paramagnetic ionic liquids, which are homogeneous in contrast to ferrofluids. Conceivable are ionic liquids with incorporated superparamagnetic particles.

Conceivable are inventive liquid droplets that do not contain ionic liquid, or conductive liquid droplets that are held on a region of a surface that has a high surface energy, wherein the surface in the vicinity of this region has a low surface energy.

It is conceivable for a condenser according to the invention to contain drops which also experience a deflection when the condenser is deflected sideways, being held on the conducting magnet, and the capacitance of the condenser changing, so that energy can also be obtained in this form of movement.

It is conceivable that in a capacitor according to the invention, a permanent magnet formed from polymers and magnetic particles is used, which contains a number of conductors, so that this composite polymer permanent magnet can both conduct current through the droplet and can hold it over itself.

Conceivable is the use of the inventive capacitor as a sensor in a motion sensor or the use of a field of such sensors for measuring the deformation of a surface.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 7898096 [0002]
• US 2012/0181901 [0002]
• DE 102012019511 [0002]

Claims (4)

Conductive fluid drop held in a Krupenkin variable capacitor. A conductive drop according to claim 1, which contains ferromagnetic particles or superparamagnetic particles in an ionic liquid, or which is formed of a paramagnetic, homogeneous ionic liquid, and which is held by a magnetic force. A conductive drop according to claim 1, which allows a capacitance change in a Krupenkin capacitor by compressing said capacitor perpendicular to the surface of its first electrode, or by a lateral deflection of said capacitor. A conductive drop according to any one of the preceding claims used in a two- or three-dimensional array of such drops for detecting the geometric deformation of that field.