A complete presentation on solar cells.
It includes working of solar cells,solar cell Models, parameters,Applications,solar energy harvesting,Generation wise comparison of solar cells,Kitchen made solar cells.This presentation can be a wild card entry to the arena of solar cells.
2. FIBONACCI SERIES:
• 0,1,1,2,3,5,8,13 ……. Aidan Dwyer
• Appear in all forms of biological processes:
branching in the trees, the pattern in which the petals of a flower are
arranged, leaves’ arrangement on a stem, the curving of the waves, spiral of
the sea shells etc.
• Fibonacci series and nature are very closely related.
7. Working:
Generation of Electron-Hole pair:
• Photon(Ephoton>Ebandgap) hitting Ntype, generates electron hole pair
Preventing Electron-Hole Recombination:
• Minority carrier hole it cant cross SC-metal interface , So Electric field at PN junction
forces this minority carrier hole from Ntype to Ptype. So preventing recombination in
NType.
Collection of light-generated majority carrier to generate a current:
• These Majority carrier electron (in NType) are collected by metal contact.
Using excited electron energy in external circuit:
• Majority carrier electrons (in NType) moves through external circuit from N to P type
dissipating its energy in the external circuit and returns to the solar cell.
• So if electron hole pair created near to PN junction, probability(recombination) =less.
• So Ntype small thickness, to penetrate to pn junction.
• More metal grid can block solar rays.
8.
9.
10.
11.
12. Collection probability:
• Probability of Collection of light generated carriers by p-n junction and contribute to the light-
generated current.
• It is more if diffusion length of carriers > distance that a light-generated minority carrier must
travel to reach PN junction.
• The collection probability :
In the depletion region is unity (as the electron-hole pair are quickly swept apart by the electric
field and are collected.)
Away from the junction, the collection probability drops.
The impact of surface passivation and diffusion length on collection probability is illustrated below.
13. Solar Cell Equations
- Solar Cell Model -
• Equations analytical
Open Circuit: I = 0, V=Voc Short Circuit: V=0, I=Isc
Ideal Values for Rseries=0 Rshunt=infinite
14. Plotting Isolar vs Vsolar gives
Open Circuit: I = 0, V=Voc
Short Circuit: V=0, I=Isc
• The power produced by the cell in Watts can be easily calculated along the I-V sweep
by the equation P=IV.
• At the ISC and VOC points, the power will be zero and the maximum value for power
will occur between the two.
• The voltage and current at this maximum power point are denoted as VMP and IMP
respectively.
18. Sensitivity to temperature:
• Increase in temperature reduce the band gap of a semiconductor, more photons have
enough energy to create e-h pairs, so ISC increases.
• In the bond model of a semiconductor band gap, reduction in the bond energy also
reduces the band gap. Therefore increasing the temperature reduces the band gap.
• By increasing temperature , bandgap decreases, So the open-circuit voltage decreases.
The impact of increasing temperature is shown in the figure below:
19. Basic Terms:
Air Mass
Fill Factor
Efficiency
ICTE
Absorption
Aging Effects
Temperature Effects
20. Fill Factor (FF):
• Its essentially a measure of quality of the solar cell.
• The FF is defined as the ratio of the maximum power from the solar cell to the product of
Voc and Isc.
• FF can also be interpreted graphically as the ratio of the rectangular areas shown in the
figure below.
21. Efficiency:
• The Electrical efficiency depends on the spectrum and intensity of the
incident sunlight and the temperature of the solar cell.
• Therefore, conditions under which efficiency is measured must be carefully
controlled in order to compare the performance of one device to another.
• Terrestrial solar cells are measured under AM1.5 conditions and at a
temperature of 25°C.
• Solar cells intended for space use are measured under AM0 conditions.
22. Quantum Efficiency :
• Its the ratio of the number of carriers collected by the solar cell to the number of
photons of a given energy incident on the solar cell.
• It may be given either as a function of wavelength or as energy.
• IPCE=1 ; for Ephoton>=Ebandgap, all photons of a certain wavelength are absorbed and
the resulting minority carriers are collected.
• IPCE=0 ; for Ephoton<Ebandgap photons as no absorption takes place.
• Also called as IPCE (Incident-Photon-to-electron Conversion Efficiency).
• It reflects the performance of the solar cell only, do not depend on the spectrum and
intensity of the incident sunlight and the temperature of the solar cell.
23. Air Mass (AM):
• It quantifies the reduction in the solar power as it passes through the atmosphere and as it is
absorbed by air and dust.
• The Air Mass is defined as:
where θ is the angle from the vertical (zenith angle).
• When the sun is directly overhead, the Air Mass is 1 (angle=0).
24. An easy method to determine the air mass is from the shadow of a vertical pole.
Air mass is the length of the hypotenuse divided by the object height h, and from
Pythagoras's theorem we get:
25. Absorbing Solar Energy
- Air Mass 1.5 -
• Solar panels do not generally operate under one atmosphere's thickness, if
the sun is at an angle to the Earth's surface the effective thickness will be
greater.
• Many of the world's major population centres, and hence solar installations
and industry, across Europe, China, Japan, the United States of America and
elsewhere (including northern India, southern Africa and Australia) lie
in temperate latitudes. An AM number representing the spectrum at mid-
latitudes is therefore much more common.
• "AM1.5", 1.5 atmosphere thicknesses, corresponds to a solar zenith angle of
48.2°, and is almost universally used to characterize terrestrial solar panels.
26. Absorbing Solar Energy
- Solar Spectrum -
• Most of solar radiation is between wavelengths of 250nm and 2500 nm. This range of
wavelengths includes infrared radiation, visible light and ultraviolet light.
• Only 70% of solar light reaches earth surface.
27. - INDIAN Power Consumption –
Area required to supply all of the electrical power by solar cells?
• INDIAN power consumption in the year 2010 = 4x1015 W-h
• Solar power at 1 sun = 1000 W/m2
• Solar cell with efficiency = 15% = can harvest 150 W/m2
• Sun shines ~ 7 hours/day
• Total power harvested in the year =150x365*7
=3.832*10^5 W-h/m2
By equating,
Need 3.8*10^5 w-h/m2*A= 4x1015 W-h /A /1010 m2
• For square area A = d2 = 1010 m2
• =>d = 100 km or d = 60 miles
• Considering space between solar panels
• => d=100 miles (1 mile=1.6Km)
• Area required to supply all of the Indian electrical power by
solar cells=160*160 km^2
28. Absorbing Solar Energy
- Optical Properties of Solar Cell Materials -
Absorption Coefficient:
• It determines how far light of a particular wavelength can penetrate into a material, before it
gets absorbed.
• Semiconductor materials have a sharp edge in their absorption coefficient, since light which
has energy below the band gap does not have sufficient energy to raise an electron across the
band gap. Consequently this light is not absorbed.
• Absorption coefficient is defined as:
29.
30. Absorption Depth:
• The distance into the material at which the light intensity drops to about 36%
of its original intensity, or alternately has dropped by a factor of 1/e.
• High energy light (short wavelength, blue light) has a large absorption
coefficient, it gets absorbed in a short distance (for silicon solar cells within a
few microns) of the surface, while red light (lower energy, longer wavelength)
is absorbed at longer distance.
• It is given by the inverse of the absorption coefficient, or α-1.
32. LIMITS ON EFFICIENCY
LOSSES
EFFICIENCY IMPROVEMENT TECHNIQUES
Multi Junction Solar Cells
Anti Reflective Coatings
Concentrators
Pyramid shaped Surfacing
33. Introduction to Solar Cells
- Narrowing gap between Existing and Theoretical PV efficiencies -
• Thermodynamic efficiency limit : theoretically possible maximum conversion efficiency of sunlight to
electricity. Its value is about 86%.
34. Issues affecting efficiency of solar cells:
Solar radiation of every wavelength is not fully utilized:
• When Eph<Ebandgap, so the light cannot be converted into electricity and is
lost.
• When Eph>>Ebandgap, so the excess energy is lost as heat.
Recombination of generated electron hole pair:
• The series and shunt resistors generated from the contacts and lattice defects
in the silicon consume some of the electricity that is generated.
• Electron-hole pair recombination instead of conversion to electricity.
35. Decrement in Surface Reflection by using Anti reflecting Coating:
• Bare silicon has a high surface reflection of over 30% ,which is bought
down to less than 10%.
• For a given thickness, index of refraction, zero reflection occurs only at a
single wavelength.
• Usually, wavelength of 0.6 µm is chosen since it is close to the peak power
of the solar spectrum.
36.
37. How do we reduce the cell costs?
• Make cells more efficient and use less expensive
semiconductor materials
– Stack multiple junctions
– Use thin films of semiconductors
– Concentrate the sunlight
38. Multi-junction solar cells:
• A stack of Semiconductors with descending order of
band-gap energies.
• The lowest wavelength (highest energy purple
light) gets absorbed by the first cell – which is
transparent to all light of lower energy (the
blues, greens, yellows and reds).
• Then the second cell absorbs the next highest
energy light after the purple (the blue) while being
transparent to light of lower energy than this (the
greens, yellows and reds), and so on……
Multi-junction solar cells
39. One method to increase the efficiency of a solar cell is
• split the spectrum
• use a solar cell material that is optimised to each section of the spectrum.
40. Introduction to Solar Cells
- Technological Improvements -
Multijunction Devices
• Stack of individual single junction cells in descending order of bandgap.
• Top cell captures high energy photons and passes rest on to lower bandgap
cells.
• Mechanical stack:
• Two individual solar cells are made independently.
• They are mechanically stacked, one on top of another.
• Monolithic stack:
• One complete solar cell is made first.
• Layers of subsequent cells are grown or deposited.
• Example: GaAs Multijunction
• Triple junction cells of semiconductors: GaAs, Ge and GaInP2.
41. Triple-Junction GaAs, Ge and GaInP2 Solar Cell
• Arranged in Descending order of bandgap Energies.
• Spectrolab has reported a conversion efficiency of 40.7% with this solar cell structure
operating at ~ 250 suns
42. Cross section of a modern silicon solar cell:
• Use Anti Reflecting Coating.
• Instead of flat Top layer, Pyramid shaped surface layer is built,
So that
Light undergoes multiple reflections and Scattering
improves Absorption of Solar light.
• Make bottom Metal contact layer also reflecting.
43. Use of Concentrators:
The incident sunlight is focused by optical elements such that a high intensity light
beam shines on a small solar cell.
A concentrator is a solar cell designed to operate under illumination greater than 1
sun.
Advantages:
• A higher efficiency potential than a one-sun solar cell.
• lower cost as same lower area cell is used.
• Drastic Temperature increase, losses in series Resistance can cause problem.
• As losses due to short-circuit current depend on the square of the current,
power loss due to series resistance increases as the square of the
concentration (As current proportional to concentration).
44. HISTORICAL DEVELOPMENT CHAIN
DIFFERENT SOLAR CELL TYPES
THEIR DESIGN
ADVANTAGES,DISADVANTAGES
GENERATION WISE SOLAR CELLS
COMPARISION
45. Introduction to Solar Cells
- Historical Developments -
o 1839: Photovoltaic effect was first recognized by French physicist Alexandre-Edmond
Becquerel.
o 1883: First solar cell was built by Charles Fritts, who coated the semiconductor selenium
with an extremely thin layer of gold to form the junctions (1% efficient).
o 1941: Russell Ohl patented the modern solar cell as “Light Sensitive Device”.
o 1954: Invention of the first practical silicon solar cell at Bell Laboratories, experimenting
with semiconductors, accidentally found that silicon doped with certain impurities was
very sensitive to light (6% efficient).
o 2008 - Solar cell efficiency reaches 40.8%(New Record). Triple Junction Solar Cell was
designed at U.S. Department of Energy's National Renewable Energy Laboratory(NREL).
o 2012 - 3D PV-cell is designed with 30% more energy efficiency (A 3-dimensional design to
trap sunlight ).
46. Uses 3-dimensional design collector to trap sunlight , where photons bounce around until they are converted
into electrons.
47. Introduction to Solar Cells
- Solar Cells Generations -
• First Generation
• Monocrystalline (single crystal) silicon wafer (c-Si)
• Polycrystalline silicon (poly-Si)
• Second Generation
• Amorphous silicon (a-Si)
• Cadmium telluride (CdTe)
• Copper indium gallium diselenide (CIGS) alloy
• Third Generation
• Photoelectrochemical (PEC) cells
• Gräetzel cells or Dye sensitized solar cell (DSSC)
• Polymer solar cells
• Nanocrystal solar cells
• Fourth Generation
• Perovskite solar cells
• Hybrid - inorganic crystals within a polymer matrix
48. Classification of Solar Cells
1G: Silicon based
2G: Thin film : CIGS
(CuInGaSe2 Cell) etc
3G: DSSC & Organic
photovoltaic cells
4G: Hybrid solar cells:
plasmonic , Inorganic in
Organic etc.
50. First Generation Solar cell Structure:
• Aluminium Back Metal contact= backing for energy transfer,
• Anti-reflective coating on top of the silicon (to maximize use of the photons hitting the
cell) =made of SiNx or TiO2,
• Metal Contact=conductive strips for energy transfer (and collection of carriers),
• Glass on the top of the cell for protection of the elements.
51. Cell material Efficiency
(Highest
till date)
Advantages Disadvantages
First
Generation
• Indirect bandgap SC material • high costs
Mono –
crystalline
27.6% • Most efficient PV modules,
• Easily available on the market,
• Highly standardised production process
• Most Expensive,
• wafers sawed from
silicon ingots, creates
wastage of silicon.
Poly-
crystalline
23.4% • less energy, less time required for production,
• lower costs,
• easily available in the market,
• highly standardised.
• More chance of
presence of defects ,
• Less efficient than
monocrystalline
(Recombination takes
place at defect sites).
Production:
• Monocrystalline si =>Czochralski(CZ) process ,High Energy Intensive process
• polycrystalline si =>Casting process (Much cheaper and simpler)
• Molten silicon poured in a mould and allowing it to cool, this process is called casting.
52. Introduction to Solar Cells
- Second Generation Solar Cells -
• Amorphous silicon cells deposited on stainless-steel ribbon or Glass layer.
• Can be deposited over large areas by plasma-enhanced chemical vapor
• deposition.
• Can be doped in a fashion similar to c-Si, to form p- or n- type layers.
• Low cost as well as low efficient
• Si not good absorber, as thickness of si reduces absorptivity still
decreases (Use Zigzag surface).
• Used to produce large-area photovoltaic solar cells.
• Can be rolled
• Bandgap ~ 1.7eV
53. Introduction to Solar Cells
- Second Generation Solar Cells -
• Cadmium Telluride (CdTe) cells deposited on glass.
– Crystalline compound formed from cadmium and tellurium with a zinc blende
(cubic) crystal structure.
– Usually sandwiched with cadmium sulfide (CdS) to form a pn junction
photovoltaic solar cell.
– Cheaper than Silicon, especially in thin-film solar technology –
not as efficient.
– Bandgap ~ 1.58eV.
• Copper gallium indium diselenide (CIGS) solar cells
– Deposited on either glass or stainless steel substrates.
– More complex heterojunction model.
– Bandgap ~ 1.38eV.
54. Second Generation Thin film Solar cell Structure :
• Window Layer:
Top layer called the window layer made of a large band gap material that absorbs the higher
energy photons.
• Absorber Layer:
Bottom layer called the absorber layer made of a smaller band gap material that absorbs the
lower energy photons, which are not absorbed by the window layer.
55. CdTe Solar Cell:
• CdTe has a direct band gap of 1.45 eV, and it is used as the absorber layer material.
• These cells also use CdS as the window layer material.
• The glass substrate for this solar cell is typically soda lime glass (for mechanical support) coated
with a thin conductive layer of tin oxide (SnO) or indium tin oxide (ITO)(Anti eflective coating).
• Finally, a back contact of Mo or W (tungsten) is deposited for energy flow.
56. Cell material Efficiency Advantages Disadvantages
Second Generation
(Thin film)
TARGET:
• To lower production costs and minimal
material consumption,
• Can use existing solar cell manufacturing
Technology.
CHARACTERISTICS:
• Direct bandgap SC material, Reduced mass,
• Flexible materials
• Heterojunction Models
• Toxicity and Limited-availability of
materials,
• Production requires new facilities, which
would greatly increase the cost of
production.
• Not much efficient as first generation
Amorphous silicon 11.4% • Less si needed for production
• cheaper.
• Thin film solar cell production.
• photodegradation over time, not much
efficient
• Extra Glass layer to provide Mechanical
strength.
• More space required for the same
power as low efficient.
Copper Indium
Gallium diselenide
(CIGS)
20.3% • Stable, more efficient than a-si.
• Better Resistant to heat than si (can be used
with concentrators)
• Not much efficient.
• More space for the same power
Cadmium Telluride
(CdTe)
16.7% • Stable, slightly more efficient.
• Cd abundance
• Good match with sunlight (1.5ev=>500nm).
• Toxic
• Not much efficient
• More space for the same power.
57. Introduction to Solar Cells
- Third Generation Solar Cells -
• Very different from the previous semiconductor devices.
• Do not rely on a traditional pn- junction to separate photo generated charge
carriers.
• Most of the Photovoltaics continues to focus on Silicon. Processing cost is
high. So there is a quest for new and cheaper materials. But there will be a
trade of between efficiency and cost. This poses a challenge in
photovoltaics.
• Devices include
– Nanocrystal Solar Cells.
– Photo electrochemical cells
• Graetzel cell (DSSC)
• Dye-sensitized hybrid solar cells.
– Polymer solar cells.
58. The DSSC or Gratzel Solar Cells :
• Brian O’ Regan & Michael Grätzel : Inventor of A low cost,
high efficiency solar cell based on dye sensitised colloidal
TiO2 films 1991.
• Michael Grätzel has been awarded “The 2010 Millennium
Technology Prize” for this invention.
• Highest Lab level efficiencies are greater than 15%.
• Cost effective compared to Si solar cells, easy to assemble
and fairly stable.
59. How do DSSCs work?
1. Electrons of dye are exited by solar energy
adsorption
2. Electrons transfer from dye to FTO via TiO2
3. Electrons reach counter electrode after working
at external load
4. 1/2I3
- + e-(Pt) 3/2 I- (at counter
electrode,cathode-pt)(regenerating the iodide).
5. 3/2I- 1/2I3
- + e- (at dye) (the to avoid
decomposition )
DSSC Layers
1. Glass coated with fluorine-
doped tin oxide(FTO)(Anode)
2. Titanium dioxide layer (acts as n-
type semiconductor)
3. Ruthenium dye
4. Electrolyte solution (Iodide , Redox
material)
5. Glass coated with
platinum(cathode)
60. DSSC Solar cells try to mimic plants Natural photosynthesis process.
Working:
• By solar energy adsorption, Electrons of dye are exited from HOMO to LUMO.
• Electrons transfer from dye to FTO via TiO2
• Thus Charge separation occurs at the interface of the dye and the semiconductor.
• Meanwhile, the dye molecule (ruthenium complexes) has lost an electron and the
molecule will decompose if another electron is not provided. So the dye strips (takes
in to VB) one from iodide in electrolyte below the TiO2, oxidizing it into tri iodide .
3/2I- -> 1/2I3
- + e- (at dye) (the to avoid decomposition )
• Electrons from FTO reach counter electrode after working at external load.
1/2I3
- + e-(Pt) ->3/2 I- (at counter electrode,cathode-pt)(regenerating the iodide).
• The triiodide (Electrolyte) then recovers its missing electron as counter electrode re-
introduces the electrons after flowing through the external circuit.
• This regenerating the iodide makes the process in this cell regenerative.
• Although the process in the DSSCs is reversible and regenerative, the highest efficiency
reported for this type of cell is only 11%.
63. • Dye acts like a light antenna, titanium dioxide acts like a semiconductor. These two
ingredients, put on a conductive glass, can transform light into electricity.
• Intially required materials: TiO2 , Iodide electrolyte solution.
STEPS:
• Coat a conducting glass slide with Titanium Dioxide.
• Stain Titanium Dioxide with the Blackberries(first electrode)
• Carbon-coated Counter Electrode(second electrode)
Assembling two electrodes:
• Use two binder clips to hold the two slides together (use filter paper to separate
electrodes).
• Now with an eyedropper add 1-2 drops of liquid Iodide/Iodine electrolyte solution
between the two slides. The solution will be drawn into the cell by capillary action and
will stain the entire inside of the slides.
• Connect multi-meter with the negative terminal attached to the TiO2 coated slide and
the positive terminal attached to the graphite coated slide.
• Measure both the current and voltage of the cell in direct sunlight and indoors.
• The maximum voltage in direct sunlight should be about 0.1 – 0.5 volts.
64. QDSCs: Quantum Dot Solar Cells:
• A semiconductor nanostructure that confines the motion of conduction band
electrons, valence band holes in all three spatial directions.
• Contains a small finite number (of the order of 1-100) of conduction band electrons,
valence band holes
Size quantization effect:
• Smaller quantum dots absorb shorter wavelengths of light, while larger quantum
dots absorb longer wavelengths of light.
• Combine different-sized quantum dots on one solar cell offers possibility to harvest
light energy over wide range of visible light with selectivity. (Rainbow Solar cell)
• Also solar cell can be made to absorb a solar wavelength region of choice.
Multiple Exciton Generation (MEG) :
• It is the phenomenon where in the absorption of a single photon leads to the
excitation of multiple electrons from the valence band to conduction band.
• Higher efficiency can be achieved compared with solar cells made of bulk
semiconductors.
65. QDSCs: Quantum Dot Solar Cells:
Compared to DSSCs, does not need the costly Ru dye
Less expensive compared to DSSC.
It can exceed Shockley Queisser limit via MEG and can offer higher
efficiency.
Solid-state, non-toxic, (even use & throw!) solar cells can be fabricated.
66. Design of rainbow solar cells
Rainbow Solar Cell: Different wavelengths of light can be absorbed by having
different-sized quantum dots.
67. Figure shows TiO2 Nanotube Array and
TiO2 nano particles with Different-Sized
CdSe Quantum Dots.
• TiO2 Nanotube Array vs TiO2 nano
particles:
Grain boundaries can affect flow of
electron, so better use nanotubes
where electron flow directly between
QD(CdSe) and electrode minimizing
recombination.
• Morphology (Structural)
dependence of Metal oxide TiO2 :
TiO2 nanotubes lead to higher efficiency
compared to TiO2 nanoparticles.
Kamat et al., JACS,130 (2008) 4007.
68. Cell material Efficiency Advantages Disadvantages
Third Generation
DSSC ( Dye sensitized
solar cells)
11.2% • Potentially regenerative .
• Very inexpensive to produce.
• Light weight.
• Works even in low-light conditions.
• More Dye cost,
• Photodegrade in a short period
of time and the dyes tend to
leak very easily.
Quantum Dot Solar
cells
6% • Low cost, Tunable band gap,
• High absorption coefficient,
• Multiple exciton generation,
• Hot electron transfer, Non Toxic.
• Low efficient
Fourth Generation
Perovskite solar cells 17.9% • Same thin-film manufacturing techniques,
• Low cost,
• Direct band gap,
• Large absorption coefficient,
• High carrier mobility.
Tandem Solar Cells 42.3% • Crosses Shockley-Queisser Limit
(More Efficient).
• High Cost
69. - Fourth Generation Solar Cells -
Perovskite Solar Cells - An Organic-Inorganic Hybrid:
• “The Next Big Thing in Photovoltaics”
• The fastest-advancing solar technology till date (from 3.8% in 2009 to a certified
17.9% in 2014).
Perovskite structure : any material with similar crystal structure as calcium titanium
oxide (CaTiO3), known as the perovskite structure.
• high charge carrier mobility and charge carrier lifetime.
• Colossal magnetoresistance (CMR) :Property of changing the electrical
resistance in the presence of a magnetic field.
• Superconductivity
• Ferroelectricity : property of certain nonconducting crystals exhibit
spontaneous electric polarization (making one side of the crystal electrically
positive and the opposite side negative) that can be reversed in direction by the
application of an appropriate electric field.
70. - Fourth Generation Solar Cells -
• Thin multi-spectrum layers can be stacked to make multi-spectrum solar cells
– Layer that converts different types of light is first.
– Another layer for the light that passes.
– Lastly is an infra-red spectrum layer for the cell.
– Converting some of the heat for an overall solar cell composite.
– More efficient and cheaper.
– Based on polymer solar cell and multi junction technology.
• Future advances will rely on new nanocrystals, such as cadmium telluride
tetrapods.
– Potential to enhance light absorption and further improve charge transport.
74. Solar Cars:
Solar car Races
• American solar challenge,
• Formula Sun Grand Prix.
• Its Competition to design, build, and drive solar-powered cars.
75. Power System
Single Solar Array-1.8m X 1.4 m - 3 panels -
840 W Generation (in Martian orbit),
Battery:36AH Li-ion
Mangalyaan Mars Craft: (Mars Orbiter Mission MOM)
With the solar panels not receiving any sunlight, the battery will then supply all the power
required for this operation.
Mechanism Solar Panel Drive Mechanism (SPDM),
Reflector & Solar panel deployment
IN SATELLITES:
76. SOLAR ROADS:
• It replaces current petroleum-based asphalt roads by a transparent driving surface with underlying solar
cells.
• They generate renewable energy that can be used by homes and businesses.
77. SOLAR BALLOON:
• The air inside the balloon gets heated by sun
radiation (with the help of black or dark
balloon material), this heated air expands and
has lower density than the surrounding air,
thus gaining buoyancy.
• Similar to a hot air balloon.
• The first human carrying pure solar balloon
flight was made on 1 May 1973.
• Used in weather forecast also.
79. SOLAR TREES:
• The Solar Tree panels charge batteries during the day and switches on its LEDs.
• They can produce light for few consecutive cloudy days.
81. SOLAR PAINT:
• polymers dissolved in a solvent creates a “paint” that
can be applied to any surface – from homes to offices
to cars.
SOLAR ROAD STUDS:
• Solar road studs LED is powered by solar cell,
placed on centre lines of road.
82. JUST IMAGINE : If solar energy combined with 3D printing and cells be printed on paper!
As printed solar panels are flexible ,the results would be revolutionary.