Repair method for sealing the back of photovoltaic modules

Abstract

A method for efficiently sealing the back of photovoltaic modules as part of a repair. The photovoltaic modules pass through several process stages one after another, beginning with a selection of repairable photovoltaic modules, their anonymization and cleaning, followed by further process stages. The further process steps include drying, coating, and treating the coating with pulsed infrared radiation. The process is completed with a check of the process and a functional test using a flash test. The process conditions and apparatus configurations in the process stages are described in detail.

Claims

1. A method for back sealing photovoltaic modules, the method which comprises: executing a plurality of process stages in succession in a continuous process, starting with a process of selecting repairable photovoltaic modules, anonymizing and cleaning the photovoltaic modules and ending with a process check and a functional test using a flash test; subsequent to the process stages anonymizing, selecting, and cleaning, executing a process stage drying with the following steps and features: drying the photovoltaic modules located on a roller conveyor, by wiping off remaining water; blowing off still remaining water using an air curtain; removing still further remaining water from upward facing backs of the photovoltaic modules by pulsed infrared radiation at <80 C. within <2 minutes, and thereby precisely adjusting an emission of the pulsating infrared radiation with an absorption of the water; and thereby complying with the following process parameters: TABLE-US-00004 throughput speed 1-2.5 m/min height of the pulsed infrared module above 1-2.5 m/min the photovoltaic modules pulse infrared module length 280-400 mm drying time 1.5-4 min electrical power density 6.3-16 kW/m.sup.2 pulsed infrared wavelength 2.5-4 m pulsed infrared emitter power 1.6-3.2 cm.sup.2 pulse infrared emitter pulse power 250-320 W/cm.sup.2 pulse infrared pulse duration 10-16 s pulsed infrared pulse frequency 40-100 kHz; subsequently executing a downstream process stage coating by evenly coating the clean and dry back surfaces of the photovoltaic modules with a liquid plastic sealing compound using spray nozzles, thereby forming a coating with a layer thickness in a wet phase from 40 to 100 m, and providing a sprayability of the sealing compound by adding of 20 to 40% of a water-soluble, environmentally friendly thinner; in a following process stage treating the coating with pulsed infrared radiation, by irradiating the back surfaces of the photovoltaic modules with pulsed infrared radiation in two stages, being drying and polymerizing, in continuous operation at <80 C. within <2 minutes, to completely evaporate initially introduced water of the thinner and to form a waterless polymeric sealant, under the following process conditions: TABLE-US-00005 throughput speed 1-2.5 m/min pulse infrared module height above the 1-2.5 m/min photovoltaic modules pulse infrared module length 580-800 mm drying time 1.5-4 min electrical power density 6.3-16 kW/m2 pulsed infrared wavelength 3.0-4.5 m pulsed infrared emitter power 1.6-3.2 cm2 pulsed infrared - emitter pulse power 250-320 W/cm2 pulsed infrared - pulse duration 12-25 s pulsed infrared - pulse frequency 40-100 kHz; subsequently polymerizing the waterless polymeric sealant by pulsed infrared radiation to form a closed layer under the following process conditions: TABLE-US-00006 throughput speed 1-2.5 m/min pulse infrared module height above the 1-2.5 m/min photovoltaic modules pulse infrared module length 580-800 mm drying time 1.5-4 min electrical power density 6.3-16 kW/m2 pulsed infrared wavelength 4.0-8.5 m pulsed infrared emitter power 1.6-3.2 cm2 pulsed infrared - emitter pulse power 250-320 W/cm2 pulsed infrared - pulse duration 3.2-15 s pulsed infrared - pulse frequency 40-100 kHz supporting the process stages drying and polymerizing by a moderate laminar air flow of 0.1-0.5 m/min with 0.1-0.25 m.sup.3/h; and finally executing process stages checking the process and functional testing using a flash test follow.

Description

BRIEF DESCRIPTION OF THE FIGURE

(1) The sole FIGURE is a flowchart illustrating a sequence of the process steps 1 through 7 according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(2) The method according to the invention for back-sealing of photovoltaic modules is in the following explained in more detail with reference to the drawing FIGURE.

(3) The overall method consists of several process stages, which are run through by the photovoltaic modules to be repaired one after another.

(4) In detail, these are the process stages: anonymization and selection1, cleaning2, drying3, coating4, treatment of the coating with pulsed infrared radiation5, checking of the process6, functional test7.

(5) The process stages are described above and specific reference is had to the above information.

(6) Systems according to the features of the invention are advantageously designed in such a way that the accommodation in a standard 40 foot high cube container, 40 ft (interior 39.475 ft, 12.032 m)8 ft (int: 7.72 ft, 2.352 m)9.5 ft (int: 8.85 ft, 2.698 m), is possible.

(7) The foregoing specification is based on German published patent application DE 10 2020 002 093 A1, dated Oct. 7, 2021, which is herewith incorporated by reference. No claim is made to the priority of the German application. Any discrepancy, however, between the German published application and the instant specification should be resolved in favor of the former.