Dehumidification of a photovoltaic module by means of electrolysis

Abstract

A photovoltaic module has at least one solar cell, wherein the solar cell is enclosed by an encapsulation apparatus, and an electrolysis unit for dehumidifying the interior of the encapsulation apparatus. The electrolysis unit has a cathode, an anode, and an ion conductor connecting the cathode and the anode. The electrolysis unit is designed to cleave water in hydrogen and oxygen. A method for dehumidifying a photovoltaic module is accomplished by the electrolysis unit.

Claims

1. A photovoltaic module, comprising: a solar cell contained within an encapsulation device, wherein the encapsulation device is selected from the group consisting of an encapsulant, a front glass panel and a back glass panel sealed along lateral edges thereof, and combinations thereof, and an electrolysis unit for dehumidifying the solar cell, the electrolysis unit at least partially disposed in an interior of the encapsulation device, wherein the electrolysis unit has a cathode, an anode and an ion conductor connecting the cathode and the anode, and wherein the electrolysis unit is configured to split water adsorbed on the ion conductor into hydrogen and oxygen and to move the hydrogen and the oxygen outside the photovoltaic module.

2. The photovoltaic module as claimed in claim 1, wherein at least the anode is arranged outside the encapsulation device so that the oxygen formed at the anode is releasable directly to the environment.

3. The photovoltaic module as claimed in claim 1, wherein the ion conductor is mounted on the inside of a part of the encapsulation device.

4. The photovoltaic module as claimed in claim 1, wherein the ion conductor constitutes a part of the encapsulation device.

5. The photovoltaic module as claimed in claim 1, wherein both the anode and the cathode are each arranged completely within the encapsulation device.

6. The photovoltaic module as claimed in claim 1, wherein the electrolysis unit is arranged opposite that side of the photovoltaic module intended for exposure of the photovoltaic module to electromagnetic radiation from the sun.

7. The photovoltaic module as claimed in claim 1, wherein the solar cell is a perovskite solar cell.

8. The photovoltaic module as claimed in claim 1, wherein the encapsulation device on a side of the photovoltaic module intended for exposure of the photovoltaic module to electromagnetic radiation from the sun is essentially transparent in a wavelength range of an activation energy.

9. The photovoltaic module as claimed in claim 1, wherein the encapsulant includes a crosslinking polymer, in particular ethylene-vinyl acetate, and the solar cell is embedded in the crosslinking polymer.

10. The photovoltaic module as claimed in claim 1, wherein the photovoltaic module is also configured in such a way that the electrolysis unit is operable directly using electrical energy generated by the solar cell.

11. A method, comprising: dehumidifying an interior volume of an encapsulation device of a photovoltaic module, which is effective to reduce an exposure of a solar cell disposed in the interior volume to water, by: adsorbing water molecules from the interior volume onto an ion conductor of an electrolysis unit, applying a DC voltage to a cathode and an anode of the electrolysis unit for a predetermined period of time in order to split the water molecules adsorbed at the ion conductor into hydrogen and oxygen, discharging the hydrogen to the cathode and the oxygen to the anode, each via the ion conductor, moving the hydrogen and the oxygen from the interior volume of the encapsulation device to outside the encapsulation device, and isolating the cathode and the anode from the applied DC voltage after the predetermined period of time.

12. The method as claimed in claim 11, wherein the predetermined period of time is in a range between 2 seconds and 2 minutes.

13. The method as claimed in claim 11, wherein the applied DC voltage is less than 10 volts.

14. The method as claimed in claim 11, wherein the DC voltage is applied at defined intervals.

15. The method as claimed in claim 11, wherein, after the DC voltage has been applied for the predetermined period of time, an electrolysis current is determined and a time at which the cathode and the anode are isolated from the applied DC voltage is selected based on the determined electrolysis current.

16. The method as claimed in claim 12, wherein the predetermined period of time is in a range between 5 seconds and 20 seconds.

17. The method as claimed in claim 13, wherein the applied DC voltage is in a range of 2.5 volts to 3 volts.

18. The method as claimed in claim 14, wherein a defined interval is once per week.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is illustrated hereinafter on the basis of the attached figures.

(2) The Figures Show:

(3) FIG. 1: an electrolysis unit having a solid-state electrolyte as ion conductor,

(4) FIG. 2: a first embodiment of the photovoltaic module according to the invention and

(5) FIG. 3: a second embodiment of the photovoltaic module according to the invention.

DETAILED DESCRIPTION OF INVENTION

(6) FIG. 1 (also referred to as FIG. 1) schematically shows an electrolysis unit 30. The electrolysis unit 30 has a first electrode that functions as cathode 31, and a second electrode that functions as anode 32. The two electrodes 31, 32 are connected to an ion conductor 33 in an electrically conductive manner. The ion conductor 33 in the example shown in FIG. 1 is a solid, for which reason it is referred to as solid-state electrolyte, for example to distinguish from otherwise customary liquid electrolytes.

(7) When a DC voltage in the low or middle single-digit volt range (for example between 1.2 volts and 5 volts) is applied, water molecules that have accumulated on the ion conductor are split into hydrogen molecules (H.sub.2) and oxygen molecules (O.sub.2). The hydrogen molecules are positively charged ions and therefore migrate to the cathode 31, to which the negative pole of the DC voltage is applied. The oxygen molecules are negatively charged ions and therefore migrate to the anode 32, to which the positive pole of the DC voltage is applied. This results in splitting and separation of the water into hydrogen molecules and oxygen molecules.

(8) FIG. 2 (also referred to as FIG. 2) depicts the electrolysis unit 30 shown in FIG. 1 in the way in which it can be integrated into a photovoltaic module 1. The photovoltaic module 1 has a multitude of solar cells 10, only one of which is shown in FIG. 2 for the sake of clarity. The solar cell 10 is enclosed by an encapsulation device 20. How the encapsulation device 20 is specifically configured is immaterial to the concept underlying the invention (a couple of possible implementations of the encapsulation of a solar cell were disclosed by way of example in the general description of the invention). The encapsulation device 20 completely encloses the solar cell 10 and thus protects it from soiling, moisture and mechanical actions.

(9) The electrolysis unit 30 is placed in a region within the encapsulation device 20. The cathode 31 and the anode 32 of the electrolysis unit 30 and the ion conductor 33 connecting the two electrodes 31, 32 are located completely within the encapsulation device 20. Only the electrical wires for supplying the electrodes extend outside of the encapsulation device 20. Care must be taken to prevent any ingress of water from the outside at the leadthroughs at which the electrical conductors are led from the inside to the outside through the encapsulation device 20 (glass panes, cured EVA, etc.).

(10) The electrolysis unit 30 is provided for water molecules that, in whatever way, still get into the interior of the encapsulation device 20. When voltage is applied, water molecules that have accumulated on the ion conductor 33 are split and migrate as gaseous hydrogen and oxygen molecules to the cathode and anode, respectively. In other words they are led off thereto. They accumulate there and become detached after a while. In the embodiment shown in FIG. 2, the encapsulation device 20 is configured such that both the hydrogen molecules and the oxygen molecules can diffuse through the material of the encapsulation device 20. They thus escape from the interior of the encapsulation device 20, and therefore the interior of the encapsulation device 20 is dehumidified in this way.

(11) FIG. 3 (also referred to as FIG. 3) shows a slightly modified embodiment of the photovoltaic module 1 according to the invention. Here, the electrolysis unit 30 is integrated into the encapsulation device 20. In particular, the ion conductor 33, here too again a solid-state electrolyte, constitutes a part of the encapsulation device 20. If, for example, the encapsulation device 20 essentially comprises two glass panes that are arranged plane-parallel to one another, a cutout region in one glass pane would be filled by the ion conductor 33. This has the advantage that the anode 32 can be arranged on the outside (i.e. outside of the encapsulation device 20) and therefore the larger oxygen molecules do not have to diffuse through the encapsulation device 20, but can escape directly to the outside.

(12) In summary, the present invention demonstrates an elegant way of keeping the interior of a photovoltaic module dry as efficiently and permanently as possible. This has great practical significance in particular for photovoltaic modules with perovskite solar cells or tandem solar cells with a perovskite portion.

LIST OF REFERENCE NUMERALS

(13) 1 Photovoltaic module 10 Solar cell 20 Encapsulation device 30 Electrolysis unit 31 Cathode 32 Anode 33 Ion conductor