Field of the invention:-
The invention is in general relates to Solar Photovoltaics and semiconductor devices. In particulars, the invention relates to a solar panel used to calibrate the light intensity for measurement of solar cell efficiency.
Background of invention:
The Silicon solar cell size is increasing with advancement of time and the efficiency of solar cells is also increasing and approaching the theoretical limits. Thus, an accurate measurement of cell efficiency is important. The most sensitive part of the measurement system is the light intensity, which can vary over a period of time and needs to be corrected very frequently. Though very sophisticated and expensive systems are available globally, a need to design an inexpensive system, which can be used by any operator without hampering the accuracy.
Measurement of light intensity for large area solar cell efficiency is quite tricky. This is due to the reason that the area of the cell is large and the reference solar cells from standard laboratories are smaller in size. If a large area solar cell is used to measure light intensity, an accurate meter with very low internal resistance to accurately measure the short circuit current of the cell is required. This setup is very expensive and cannot be used by less skilled operator. Therefore, a new idea has been conceived where the light intensity of the incident light can be measured in a very cost effective manner.

US9153710B2 discloses a solar power system may include a combiner module, one or more rows of solar panels connected to the combiner module, and one or more wiring circuits connecting the one or more rows of solar panels to the combiner module. Each circuit may include an inter-module wiring arrangement that connects individual solar panels to each other in series, and a return wiring arrangement that connects the inter-module wiring arrangement to the combiner module. Each inter¬module wiring arrangement may be arranged such that at least some solar panels are wired to other solar panels in the same row in a substantially alternating manner, such that non-adjacent solar panels in the same row are wired directly in series to each other. This arrangement may reduce the total length of harness wires needed to connect the one or more panel rows to the combiner box, as compared with conventional wiring schemes.
US05908962 discloses a method for installing solar collector panels as part of the roof of a building. Chalk lines are scribed on the roof to define the center of each vertical roof joist and to define the upper and lower extremes of the roof over which the solar collector panels are to be mounted. Upper and lower mounting brackets are aligned along the upper and lower horizontal scribed chalk lines and are attached through the roof to the joists as determined by the vertical chalk lines. Vertical rails are then mounted between the upper and lower brackets, aligned over the vertically scribed lines and mounted to the joists. One or a plurality of the solar collector panels are then installed between the vertical rails and between the upper and lower brackets. Cover and weather sealing plates are then installed to protect the mounting system and the solar collector panels from the environment.

US20160027945A1 discloses a solar power system may include a combiner module, one or more rows of solar panels connected to the combiner module, and one or more wiring circuits connecting the one or more rows of solar panels to the combiner module. Each circuit may include an inter-module wiring arrangement that connects individual solar panels to each other in series, and a return wiring arrangement that connects the inter-module wiring arrangement to the combiner module. Each inter-module wiring arrangement may be arranged such that at least some solar panels are wired to other solar panels in the same row in a substantially alternating manner, such that non-adjacent solar panels in the same row are wired directly in series to each other. This arrangement may reduce the total length of harness wires needed to connect the one or more panel rows to the combiner box, as compared with conventional wiring schemes.
Object of the invention:-
An object of the invention is to develop an economic reference solar panel for quick measurement of light intensity for solar cell.
Another object of the invention is to provide a solar panel that comprises plurality of smaller units of the solar cell to form a single solar panel to enhance accuracy.
Summary of the invention:
A new apparatus has been conceived where the light intensity of the incident light can be measured in a very cost effective manner by any operator.

Instead of using single Silicon solar cell; a small panel is used where plurality small Silicon solar cells are connected in series and spread over larger area. The Voc of the panel is about 4 V and current at one sun is approx 250 mA. An inexpensive digital ampere meter of 1 ampere range is used to measure short circuit current (Isc). The variation in Isc with intensity is observed by increasing the gap between light source and the panel. Due to its, design very fine variation in the light intensity can be measured and correction factor can be applied leading to very accurate measurement of cell efficiency.
Brief description of accompanying drawing:-
Fig. 1 shows schematic diagram of the arrangement in accordance to the invention.
Detailed description of the preferred embodiment:-
A small panel (1) is used where seven small Si solar cells (2) of about 9cm2 area each are connected in series and spread over larger area (75cm2) of the incident light. The Voc of the panel is about 4 V and current at one sun is around 250 mA. The small panel is fixed to a flat plastic sheet and an inexpensive digital ampere meter of 1 ampere range is used to measure short circuit current (Isc). The variation in Isc with intensity is observed by increasing the gap between light source and the panel/cell. The advantage of using a number of small cells connected in series is that the area covered by the panel is large i.e. the Isc measured

by the panel represents the average light intensity of light. Due to its high voltage and low current design the variation in Isc is very sensitive to variation in light intensity. Very fine variation in the light intensity can be measured and correction factor can be applied leading to very accurate measurement of cell efficiency by comparing the Isc with a standard reference cell.

We claim:-
1. A solar panel of reduced size for generating electricity by absorption of solar rays the said device comprising plurality of uniform-shaped solar cell interlocked adjacently on the surface area of the solar panel made incident to the light source, wherein the solar panel is fastened to a flat sheet and coupled to a digital ampere meter to measure short circuit current.
2. The solar panel as claimed in claim 1, wherein the flat sheet may be of plastic material.

3. The solar panel as claimed in claim 1, wherein variation in the short circuit current with intensity is obtained by increasing the gap between the solar light source and the said solar panel.
4. The solar panel as claimed in claim 1, wherein solar cells interlocked adjacently are seven in number.
5. The solar panel as claimed in claim 1, as illustrated in the
accompanying drawings.