achyut final prsnt ppt

7/27/2019 Achyut Final Prsnt Ppt

1/22

SOLAR PHOTOVOLTAIC CELL

Achyut Shukla

14th

Aug 2013


2/22

About the company

Central Electronics Ltd. is a public sector enterprise, under theadministrative control of the Dept. Of Scientific & IndustrialResearch.

CEL is a pioneer in the field of solar Photovoltaic in the countryand is today ranked among the first few in the world in this area of

activity. CEL is also credited with many firsts in the country,professional Ferrites being one of them.

CEL is presently engaged in the development, production and saleof selected electronic components (Professional Ferrites,Electronics Ceramics and Phase Shifters), selected electronicsystems, solar photovoltaic cells, modules and SPV systems and to

take up engineering development & production based onindigenous technology developed through in house efforts or knowhow from National Laboratories / Institutions.


3/22

Solar Energy

Energy obtained from the sun is called solar energy.Though low grade energy with temporal and spatialvariation is available from the sun, it is clean, cheap,abundant and a very attractive alternate source of energy.

Solar energy spectrum can be approximated by black bodyspectrum at 5900 k (E Vs ).

The energy of sun spectrum extends from 0.3 to 2.5m ofwavelength and its peak is at wavelength of 0.5m.

Solar Energy received at the surface of the earth is around1000W/m2 over an entire year.


4/22

Solar Photovoltaic Effect

The photovoltaic effect is the means by which solar

panels or photovoltaic modules generate electricityfrom light. A solar cell is made from a semiconductormaterial such as silicon

The operation of a photovoltaic (PV) cell requires 3 basicattributes:

1. The absorption of light, generating either electron-hole pairsor excitants.

2. The separation of charge carriers of opposite types.

3. The separate extraction of

those carriers to an external

circuit.


5/22

Solar Cell

A solar cell is any device that directly converts the energy in light intoelectrical energy through the process of photovoltaic

The solar cell works in three steps:

1. Photons in sunlight hit the solar panel and are absorbed by

semiconducting materials, such as silicon.2. Electrons (negatively charged) are knocked loose from their atoms,causing an electric potential difference. Current starts flowing throughthe material to cancel the potential and this electricity is captured. Dueto the special composition of solar cells, the electrons are only allowedto move in a single direction.

3. An array of solar cells converts solar energy into a usable amount ofdirect current (DC) electricity.


6/22

Specifications 4 inch round cells 5 inch Pseudo square cells

Isc 2.5 A 4.6 A

Voc 605 mV 605 mV

Pm(typical) 1.05 W 1.95 W

Pm with AR Coating

(Optional)1.15 W 2.13 W

Modules wattage from 36 Cells

(Non AR Coated)38 Wp 74 Wp

Types of Solar Cells


7/22

Fabrication Of Solar Cell


8/22

1. Surface Preparation

Wafers are cleaned to make it free from impuritiesas these impurities may affect the electrical

performance of the solar cell.

Polishing is to ensure that the wafer surface is free

from any saw cut marks.


9/22

2. Texturisation or Alkaline Etching Texturisation is to get maximum absorption of sunlight

and uniform Texturisation surface on silicon wafer byformation of tiny pyramids.

When a ray of sunlight falls on the textured flat SiliconSubstrate and then due to pyramid multiple reflectionoccur on pyramid surface which causes absorption of moresunlight


10/22

3. Diffusion

This process forms a negative junction over the p-typesubstrate. This, therefore, make a p-n junction.

The texturised wafer is placed on printing chuck.

The diffusion paste is transferred on the siliconwafer with the help of screen by using squeeze. Theprinted wafers are then placed on the belt ofdiffusion furnace by using tweezers. The diffusedwafers are then collected on the receiver &

undiffused wafer side is marked by quartz foridentifications of p-type.


11/22

4. Edge Isolation or Plasma Etching

The purpose of the plasma etching is to ensure that

n-type & p-type surface of the diffuse wafer are

isolated from each other

Plasma materials attack the Stack of silicon wafer

unnecessary part of wafer will be affected and part

is removed.


12/22

5. Anti Reflection Coating

It reduces interference effects in reflected wave

from the anti-reflection coating out of phase with

the wave reflected from the semiconductor

surfaces. The thickness of the AR coating should be quarter

of the wavelength of incident wave.


13/22

Comparison of surface reflection from a silicon solar cell, with and without a typical anti-

reflection coating


14/22

6. Front Contact Printing

The basic requirement of front contact are

1. Improving the current carrying capability.

2. Increasing the light collection by reducing the

shadowed area

In Front contact printing two most importantparts of solar cell are made-

1. Grid of very fine circuit lines known as Fingers.

2. Larger collecting lines known as Bus-Bars.


15/22

Close up of a finished printed cell. Shows the grid and finger by top view and side

They have a spacing of about 3 mm.


16/22

7. Back Contact Printing

It is created on the rare side of solar cell (P side).

It is mainly used for soldering purpose.

contact created on the rare side


17/22

8. Firing

This process ensures a good ohmic contact

between the paste and wafer otherwise no

current will flow through it. It also lowers the solar

cell resistance.

Solar Cell


18/22

Solar Modules

A module is simply an

array of solar cells in

series or parallel as per

electrical requirements

A solar module is the

power source of an SPV

system
http://wxeq.en.alibaba.com/product/0/50277827/Solar_Modules/showimg.htmlhttp://wxeq.en.alibaba.com/product/0/50277827/Solar_Modules/showimg.htmlhttp://wxeq.en.alibaba.com/product/0/50277827/Solar_Modules/showimg.htmlhttp://wxeq.en.alibaba.com/product/0/50277827/Solar_Modules/showimg.htmlhttp://junweisolar.en.alibaba.com/product/50384732/51743281/MONO_140W_180W_125cell_/Mono_140W_Solar_Module/showimg.htmlhttp://prostarele.en.alibaba.com/product/50220447/51657999/Solar_Power_System/Solar_Panel/showimg.html


19/22

Applications

1. Solar water pumping systems for irrigation or drinking purposes

A Solar Photovoltaic Water Pumping System essentially

consists of an SPV panel or array directly powering a

water pump. Water pumped during day can be stored in

the storage tanks for use during night. The generated

electricity from the SPV array is fed to the pumpthrough a switch. Normally low storage batteries are

provided, as the water can be stored in the storage tanks

if required.

SPV array


20/22

2. Village power plant..

A view of 100 kWp Grid Interactive Power plant installed &

commissioned at Kalyanpur, Aligarh,

The power plants being

modular in nature can be

augmented in case of

increased demand for power.

3. Medical Refrigeration

Solar Powered Refrigerator

PV Modules for the

Solar Powered Refrigerators


21/22

4. Industrial applications

A Cathodic Protection (CP) Station for Oil/Gas pipeline

Very Low Power TV Transmitter

Obstruction warning light at Airports

Far end System of the Solar Powered Railway Level

Crossing Radio warning System (SOLAGARD)


22/22

THANKYOU

achyut final prsnt ppt

Documents