에너지재료
Lecture 1: Introduction to Solar Cells,
Cells Photovoltaic Effect
전자 및 에너지 재료 연구실
Solar Cells
‰ Photon Energy
gy
E = hν =
hc
λ
h = planck
planck' s contant(6.
contant(6 626 ×10-34 J • sec)
Although light behaves like a wave,
wave having both a wavelength and a frequency,
frequency a
series of experiments by Planck and Einstein in the early 1900s showed that it also
exhibits particle-like behavior. These light particles are called photons, and the
energy off a given
i
particle
i l off light
li h can be
b computedd from
f
the
h simple
i l relationship.
l i hi
전자 및 에너지 재료 연구실
Solar Energy
gy
Solar constant (태양상수) : 대기권 가까이에
도달한 단위시간당 (min) 태양방사에너지의
밀도 = 1
1.38
38 KW/m2
전자 및 에너지 재료 연구실
Air Mass
`
A way of describing an atmospheric path is called the
relative optical path length
length, which is commonly
simplified to air mass
Perpendicular
to the earth
AM = 1/cosθ
Zenith angle (θ)
Atmosphere
전자 및 에너지 재료 연구실
Earth
surface
Solar spectrum
p
전자 및 에너지 재료 연구실
What does solar cell do?
전자 및 에너지 재료 연구실
Photovoltaic effect
• Kinetic energy of emitted electron is related to the light frequency and
cathode materials
• Saturation current is related to the light intensity
전자 및 에너지 재료 연구실
Photogeneration
g
and Separation
p
전자 및 에너지 재료 연구실
Solar cell structure
전자 및 에너지 재료 연구실
Solar p
power generation
g
plants
p
전자 및 에너지 재료 연구실
Panel tilting
g
전자 및 에너지 재료 연구실
Concept
p of PV-plants
p
전자 및 에너지 재료 연구실
BIPV ((Building
g Integrated
g
Photovoltanics))
전자 및 에너지 재료 연구실
BIPV ((Building
g Integrated
g
Photovoltanics))
전자 및 에너지 재료 연구실
BIPV ((Building
g Integrated
g
Photovoltanics))
전자 및 에너지 재료 연구실
Aerospace
p
Applications
pp
(HELIOS)
(
)
전자 및 에너지 재료 연구실
Aerospace
p
Applications
pp
(HELIOS)
(
)
전자 및 에너지 재료 연구실
Aerospace
p
Applications
pp
(HELIOS)
(
)
전자 및 에너지 재료 연구실
Flexible Photovoltanics
전자 및 에너지 재료 연구실
Solar Cells
‰ BASIC RESEARCH CHALLENGES FOR SOLAR ELECTRICITY
z Edmund Becquerel discovered the photovoltaic (PV) effect in 1839
z Voltage and a current were produced when a silver chloride electrode immersed in
an electrolytic solution and connected to a counter metal electrode was illuminated
g
with white light
z The birth of the modern era of PV solar cells occurred in 1954, when D. Chapin, C.
Fuller and G.
Fuller,
G Pearson at Bell Labs demonstrated solar cells based on p
p-n
n junctions in
singlecrystal Si with efficiencies of 5–6%
z From the mid 1950s to the early 1970s
1970s, PV research and development (R&D) was
directed primarily toward space applications and satellite power.
z In
I 1973,
1973 a greatly
l iincreased
d llevell off R&D on solar
l cells
ll was initiated
i i i d due
d to oil
il
embargo
전자 및 에너지 재료 연구실
Solar Cells
World PV cell/module production (in MWp)
z Total global PV (or solar) cell production increased from less than 10 MWp/yr in
1980 tto about
b t 11,200
200 MW
MWp/yr
/ in
i 2004.
2004
z The “peak watt” (Wp) rating is the power (in watts) produced by a solar module
illuminated under the following standard conditions
z AM (Ai
(Air M
Mass)) 1.5:
1 5 1,000
1 000 W/
W/m2
2 iintensity,
i 25°C ambient
bi temperature, andd a
spectrum that relates to sunlight that has passed through the atmosphere when the
sun is at a 42° elevation from the horizon
전자 및 에너지 재료 연구실
Solar Cells
‰ COST
z Higher PV efficiency directly impacts the overall electricity cost, because higherefficiency cells will produce more electrical energy per unit of cell area over the cell
lifetime.
g
of merit for PV cell modules (($/Wp)
p) is determined by
y the ratio of
z The cost figure
the module cost per unit of area ($/m2) divided by the maximum amount of electric
power delivered per unit of area (module efficiency multiplied by 1,000 W/m2, the
peak insolation power).
power)
전자 및 에너지 재료 연구실
PV power costs ($/Wp) as function of module efficiency and areal cost (Source
: Green 2004)
전자 및 에너지 재료 연구실
Solar Cells
z Cost p
per peak
p
watt ($/Wp)
($ p) is indicated by
y a series of dashed straight
g lines having
g
different slopes.
z Present single-crystalline Si PV cells,
cells with an efficiency of 10% and a cost of
$350/m2, thus have a module cost of $3.50/Wp.
z The
Th area labeled
l b l d I in
i Figure
Fi
2 represents
t the
th first
fi t generation
ti (Generation
(G
ti I) off
solar cells and covers the range of module costs and efficiencies for these cells.
z Areas labeled II and III in Figure 2 present the module costs for Generation II
(thin-film PV) and Generation III (advanced future structures) PV cells.
전자 및 에너지 재료 연구실
Solar Cells
Improvements in solar cell efficiency, by system, from 1976 to 2004
z The efficiencies of commercial (or even the best prototype) modules are only
about 50–65%
% of the efficiencyy of the best research cells.
전자 및 에너지 재료 연구실