FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
AND
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13) “METHOD FOR PROVIDING COATING ON PHOTOVOLTAIC PANEL”
We, Bajaj Electricals Limited, an Indian national, of 45/47, Veer Nariman Road, Fort, Mumbai ‐ 400001, Maharashtra, India.
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF INVENTION
The present invention generally relates to maintenance of photovoltaic (PV) panels. In particular, the present invention relates to a method to provide a coating on PV panels to facilitate easier cleaning of the PV panels.
BACKGROUND OF THE INVENTION
This section is intended to provide information relating to the field of disclosure and thus, any approach or functionality described herein should not be assumed to qualify as prior art merely by its inclusion in this section.
A photovoltaic (PV) panel comprises a photosensitive material (such as Silicon) enclosed in a casing. The PV panel is configured to, in response to receiving sunlight (or other electromagnetic radiation), generate electric power. A PV panel can be used as a stand-alone module for production of electric power, or a plurality of PV panels can be connected in an array to cumulatively generate electric power.
In order to receive sunlight, the PV panel is typically placed outdoors. Due to the PV panel being located outdoors, the PV panel is also likely to encounter atmospheric, or ambient problems, such as water, dust, and damage to the casing enclosing the photosensitive material. Such problems may result in reduced efficiency of generation of electric energy, as well as reduced operating life of the PV panel. Further, conventional PV panels require greater resources (such as water) for cleaning, and furthermore, conventional PV panels have to be cleaned at greater frequency. There is, thus an increased cost of resources, and time to maintain the PV panel at optimal operation.
There is, therefore, a requirement in the art for a provision of a PV panel that can be easily and less frequently cleaned using fewer resources without adversely affecting the efficiency of the PV panel.

SUMMARY OF THE INVENTION
This section is intended to introduce one or more aspects and/or embodiments of the present disclosure in a simplified form and is not intended to identify any key advantages or features of the present disclosure.
In an aspect, the present invention provides a method for providing a coating on a photovoltaic (PV) panel, comprising: cleaning an active surface of the PV panel using a wiping medium and a cleaning fluid; depositing on the active surface of the PV panel at least a coating of precursor material using a depositing medium; subjecting the coated active surface of the PV panel to a first curing treatment to decrease the moisture content of the deposited precursor material; and subjecting the coated active surface of the PV panel to a second curing treatment.
In an aspect, cleaning the active surface of the PV panel is conducted in a dust-free environment at a temperature in the range of 40 - 50 ℃, and relative humidity (RH) in the range of 70 - 80%.
In an aspect, the cleaning fluid is selected from the group comprising iso-propyl alcohol, ethyl alcohol, methyl alcohol, acetone, and mixtures thereof.
In an aspect, depositing the coating of precursor material is conducted in a dust-free environment.
In an aspect, the precursor material comprises silicon-based polymers.
In an aspect, the wiping medium and the depositing medium comprise a microfiber cloth made of a material comprising at least a polyester, at least a polyamide, or combinations thereof.
In an aspect, the weight ratio of at least a polyester to at least a polyamide is in the range of 1:1 - 4:1.
In an aspect, the microfiber cloth has a denier count in the range of 0.2 - 0.5.
In an aspect, the first curing treatment comprises heating the coated active surface of the PV panel for a period of 2 - 5 minutes in a dust free environment having temperature in the range of 40 - 50 ℃, and RH in the range of 70 - 80%.
In an aspect, the method further comprises buffing using a buffing medium, the coated active surface of the PV panel.

In an aspect, the second curing treatment comprises heating the coated active surface of the PV panel for a period of 60 - 100 hours in a dust free environment having temperature in the range of 80 - 100 ℃, and RH in the range of 40 - 60%.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The present disclosure, both as to its organization and manner of operation, together with further objects and advantages, may best be understood by reference to the description, taken in connection with the accompanying drawings. These and other details of the present invention will be described in connection with the accompanying drawings, which are furnished only by way of illustration and not in limitation of the scope of the present disclosure.
FIG. 1 illustrates a schematic flow diagram for a method for providing a coating on a photovoltaic (PV) panel, according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of one or more embodiments of the present disclosure. It will be apparent, however, that embodiments of the present disclosure may be practiced without these specific details. Several features described hereafter may each be used independently of one another or in any combination with other features. An individual feature may not address any of the problems discussed above or may address only some of the problems discussed above. Some of the problems discussed above may not be fully addressed by any of the features described herein. Example embodiments of the present disclosure are described below, as illustrated in various drawings, in which same reference numerals refer to the same parts throughout the different drawings.
The present invention provides a method for providing a coating on a photovoltaic (PV) panel. The method comprises cleaning an active surface of the

PV panel using a wiping medium and a cleaning fluid; depositing on the active surface of the PV panel at least a coating of precursor material using a depositing medium; subjecting the coated active surface of the PV panel to a first curing treatment to decrease the moisture content of the deposited precursor material; and subjecting the coated active surface of the PV panel to a second curing treatment.
In one application, the PV panel is a stand-alone panel purposed with generating energy to be either stored for later use, or for redistributing to an electric grid. In another application, the PV panel is part of an integrated system comprising a device or an apparatus, where the PV panel is purposed with generating energy for operation of the device or apparatus. An example of such an integrated system is a PV panel-powered luminaire.
In an embodiment, the active surface of the PV panel comprises an optically transparent material, such as glass. In an embodiment, cleaning the active surface of the PV panel is conducted in a dust-free environment. In an example, the dust-free environment is a clean room. In an embodiment, cleaning the active surface of the PV panel is further conducted at a temperature in the range of 40 - 50 °C, and a relative humidity (RH) in the range of 70 - 80%.
In an embodiment, the cleaning fluid is selected from the group comprising iso-propyl alcohol, ethyl alcohol, methyl alcohol, acetone, and mixtures thereof. In a preferred embodiment, the cleaning fluid is iso-propyl alcohol having analytical grade, and a purity of at least 99.9%.
In an embodiment, depositing the coating of precursor material is conducted in a dust-free environment. In an example, the dust-free environment is a clean room. In an embodiment, the coating of precursor material is conducted subsequent to cleaning the active surface of the PV panel, in the same dust-free environment.
In an embodiment, the precursor material comprises silicon-based polymers. In an embodiment, the material can be poly-siloxane. In another embodiment, the material can be nano-silica based.
In an embodiment, the wiping medium comprises a microfiber cloth made of a material comprising at least a polyester, at least a polyamide, or combinations

thereof. In an embodiment, the polyamide is nylon. In an embodiment, the polyester is PET. In an embodiment, the weight ratio of at least the polyester to at least the polyamide is in the range of 1:1 - 4:1. In a preferred embodiment, the weight ratio of at least the polyester to at least the polyamide is 80:20. In an embodiment, the microfiber cloth has a denier count in the range of 0.2 - 0.5. In a preferred embodiment, the microfiber cloth has a denier count of 0.4 denier.
In an embodiment, the depositing medium comprises a microfiber cloth made of a material comprising at least a polyester, at least a polyamide, and combinations thereof. In an embodiment, the weight ratio of at least the polyester to at least the polyamide is in the range of 1:1 - 4:1. In a preferred embodiment, the weight ratio of at least the polyester to at least the polyamide is 80:20. In an embodiment, the microfiber cloth has a denier count in the range of 0.2 - 0.5. In a preferred embodiment, the microfiber cloth has a denier count of 0.4 denier.
In an embodiment, the first curing treatment comprises heating the coated active surface of the PV panel for a period of 2 - 5 minutes. In an embodiment, the first curing treatment occurs in a dust free environment. In an example, the dust-free environment is a clean room. In an embodiment, the first curing treatment is conducted subsequent to coating of precursor material, in the same dust-free environment. In an embodiment, the first curing treatment comprises heating the coated active surface of the PV panel to a temperature in the range of 40 - 50 °C, and RH in the range of 70 - 80%.
In an embodiment, the method further comprises buffing using a buffing medium, the coated active surface of the PV panel. In an embodiment, the buffing is conducted on the coated active surface of the PV panel after the first curing treatment. In an embodiment, the buffing medium comprises a microfiber cloth made of a material comprising at least a polyester, at least a polyamide, and combinations thereof. In an embodiment, the weight ratio of at least the polyester to at least the polyamide is in the range of 1:1 - 4:1. In a preferred embodiment, the weight ratio of at least the polyester to at least the polyamide is 80:20. In an embodiment, the microfiber cloth has a denier count in the range of 0.2 - 0.5. In a preferred embodiment, the microfiber cloth has a denier count of 0.4 denier.

In an embodiment, the second curing treatment comprises heating the coated active surface of the PV panel for a period of 60 -100 hours. In an embodiment, the second curing treatment occurs in a dust free environment. In an example, the dust-free environment is a clean room. In an embodiment, the second curing treatment is conducted subsequent to the first curing treatment, in the same dust-free environment. In another embodiment, the second curing treatment is conducted subsequent to buffing the coated active surface of the PV panel, in the same dust-free environment. In an embodiment, the second curing treatment comprises heating the coated active surface of the PV panel to a temperature in the range of 80 - 100 °C, and RH in the range of 40 - 60%.
In an embodiment, after each step of the method, an inspection is carried out to determine the quality of the outcome of the completed step.
The time, temperature, and RH parameters for the second curing treatment cause a polymerization reaction of the precursor material, resulting in the formation of silicon-oxygen bonds at the expense of hydrogen loss from the active surface of the PV panel, transforming the precursor material to a dense ceramic with cross-linked layers. Oxygen present on the active surface of the PV panel bonds with silicon from the precursor material to form the coating. The oxygen and silicon are bound to each other via hydrogen bonds. Hydrogen bond formation ensures good silicon-oxygen based curing mechanism via chemisorption, further allowing for good adhesion of the coating on the active surface of the PV panel.
In an embodiment, the obtained coating on the active surface of the PV panel after the second curing treatment is a nano-coating with a high surface to volume ratio. In an embodiment, the coating has a thickness in the range of 5 to 10 microns. In a preferred embodiment, the coating has a thickness of 7 microns.
In an embodiment, the coating provides the active surface of the PV panel with properties, such as low surface energy, increased hydrophobicity, increased abrasion resistance, reduced surface roughness, and improved light transmission.
Surface energy as used herein refers to a measure of excess energy on the active surface of the PV panel, which affects the force of adhesion that particles

have with the active surface of the PV panel. The coating of the present invention lowers the surface energy of the active surface of the PV panel, thereby reducing a force of adhesion between the active surface of the PV panel and particles, such as dust, water droplets, etc. Thus, the coating facilitates easy clearing off of particles resting on the active surface of the PV panel.
Hydrophobicity as used herein refers to a contact angle formed between a drop of a liquid (such as water) and the active surface of the PV panel. The coating of the present invention increases hydrophobicity of the active surface of the PV panel, such that the contact angle between the active surface of the PV panel and the liquid droplet increases to a value equal to or greater than 90 degrees, thereby causing the liquid droplet to slide or roll away and not adhere to the active surface of the PV panel. In other words, the coating facilitates repelling of liquid droplets from the active surface of the PV panel.
Abrasion resistance as used herein refers to a capacity of the active surface of the PV panel to not get scratched or damaged due to friction with commonly present particles and objects, such as, without limitations, dust, twigs, leaves, bird nail, etc. The coating of the present invention increases the abrasive resistance of the active surface of the PV panel and limits damage due to friction of the active surface of the PV panel with objects.
Surface roughness as used herein refers to a roughness of the active surface of the PV panel. Low surface roughness results in fewer locations on the active surface of the PV panel where particulate matter, such as dust can get lodged in. The coating of the present invention reduces a surface roughness of the active surface of the PV panel, thereby resulting in less dust being lodged on the active surface of the PV panel, thereby facilitating easy cleaning of the active surface of the PV panel.
Light transmission as used herein refers to a capacity of the active surface of the PV panel (generally made of optically transparent material, such as glass) to transmit light therethrough. Good light transmission allows a greater degree of light to be transmitted therethrough, to be made available to the photosensitive component of the PV panel. The coating of the present invention reduces reflection

of the incident light on the active surface of the PV panel, thereby allowing a greater portion of the incident light to pass therethrough, thus improving effectiveness of collection of light by the photosensitive component of the PV panel.
The above properties enable the PV panel to have a longer operating life, reduce damage to it, make its maintenance easy and economic, thereby improving efficiency of operation of the PV panel.
FIG. 1 illustrates a schematic flow diagram for a method 100 for providing a coating on a photovoltaic (PV) panel, according to an embodiment of the present invention. At step 102, the method 100 comprises cleaning an active surface of the PV panel using a wiping medium and a cleaning fluid. At step 104, the method 100 comprises depositing on the active surface of the PV panel at least a coating of precursor material using a depositing medium. At step 106, the method 100 comprises subjecting the coated active surface of the PV panel to a first curing treatment to decrease the moisture content of the deposited precursor material. At step 108, the method 100 comprises subjecting the coated active surface of the PV panel to a second curing treatment.
In an exemplary implementation, a conventional PV panel and a PV panel subjected to the method 100 of the present invention are cleaned using water. The conventional PV panel, and the coated PV panel were both previously exposed to atmospheric, or ambient conditions for a period of 3 to 4 weeks.
The conventional PV panel required 3 to 4 liters of water to be cleaned. Further, the power output of the conventional PV panel after being cleaned was 1090 Watts per day (W/day).
In contrast, the coated PV panel required 1 liter of water to be cleaned. Further, the power output of the coated PV panel after being cleaned was 1233 W/ day.
From the above data, it may be inferred that the PV panel coated using the method of the present invention requires less water to be cleaned, relative to a conventional PV panel. Thus, the coated PV panel consumes fewer resources to be

maintained. Further, the coated PV panel generates a higher output relative to the conventional PV panel. Thus, the coated PV panel has a higher output efficiency. While the preferred embodiments of the present disclosure have been described hereinabove, it may be appreciated that various changes, adaptations, and modifications may be made therein without departing from the spirit of the disclosure and the scope of the appended claims. It will be obvious to a person skilled in the art that the present disclosure may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments may be considered in all respects only as illustrative and not restrictive.
LIST OF REFERENCE NUMERALS
100 Method 102 Step 104 Step 106 Step 108 Step

I/We Claim:
1. A method (100) for providing a coating on a photovoltaic (PV) panel,
comprising:
- cleaning an active surface of the PV panel using a wiping medium and a
cleaning fluid; - depositing on the active surface of the PV panel at least a coating of
precursor material using a depositing medium; - subjecting the coated active surface of the PV panel to a first curing
treatment to decrease the moisture content of the deposited precursor
material; and ‐ subjecting the coated active surface of the PV panel to a second curing
treatment.
2. The method (100) as claimed in claim 1, wherein cleaning the active surface of the PV panel is conducted in a dust-free environment at a temperature in the range of 40 - 50 ℃, and relative humidity (RH) in the range of 70 - 80%.
3. The method (100) as claimed in claim 1, wherein the cleaning fluid is selected from the group comprising iso-propyl alcohol, ethyl alcohol, methyl alcohol, acetone, and mixtures thereof.
4. The method (100) as claimed in claim 1, wherein depositing the coating of precursor material is conducted in a dust-free environment.
5. The method (100) as claimed in claim 1, wherein the coating precursor material comprises silicon-based polymers.

6. The method (100) as claimed in claim 1, wherein the wiping medium and the depositing medium comprise a microfibre cloth made of a material comprising at least a polyester, at least a polyamide, or combinations thereof.
7. The method (100) as claimed in claim 6, wherein the weight ratio of at least a polyester to at least a polyamide is in the range of 1:1 - 4:1.
8. The method (100) as claimed in claim 6, wherein the microfiber cloth has a denier count in the range of 0.2 - 0.5.
9. The method (100) as claimed in claim 1, wherein the first curing treatment comprises heating the coated active surface of the PV panel for a period of 2 -5 minutes in a dust free environment having temperature in the range of 40 -50 ℃, and RH in the range of 70 - 80%.

10. The method (100) as claimed in claim 9, further comprising buffing using a buffing medium, the coated active surface of the PV panel.
11. The method (100) as claimed in claim 1, wherein the second curing treatment comprises heating the coated active surface of the PV panel for a period of 60 - 100 hours in a dust free environment having temperature in the range of 80 -100 ℃, and RH in the range of 40 - 60%.