CHAPTER THREECHAPTER THREE

THE SOLAR CELL THE SOLAR CELL TECHNOLOGYTECHNOLOGY

2e A G.I. Module Energie Solaire

Copyright, 2006 © Ahmed S. Bouazzi

المدرسة الوطنية

للمهندسين بتونس

World production (MW)World production (MW)

'90 '92 '94 '96 '98 '000

50

100

150

200

PV systems shipping (1995)PV systems shipping (1995)

17

9.5

2.6

2.5

2

0.6

0.2

0.1

Siemens Solar

Solarex

Solec international

Astropower

Ase Americas

USSC

Entech

Avanced PV Systems

0 5 10 15 20

Solar panels sold in 1995 (Megawatts)

SiO2 + 2C Si (solid) + 2CO (gas)

ELECTRODE SiO + C

CO

2 FURNACE

Silicon PurificationSilicon Purification

SEEDQUARTZ

CRUCIBLE

SUSCEPTOR

HEATINGCOIL (RF)

INTERFACESOLID-LIQUID

ARGONCRYSTAL

FUSED Si

Czochralski Crystal PullingCzochralski Crystal Pulling

The Silicon IngotThe Silicon Ingot

HEATINGCOILS

CRUCIBLE

COOLING AIRSOLIDIFICATIONPOINT

FUSED SILICON

Heat Exchange Method Heat Exchange Method (HEM)(HEM)

DIAMONDEDGE

INGOT

SAW

Inner-Diameter SawInner-Diameter Saw

Multiwire SawMultiwire Saw

Si Wafers Sliced From Si Wafers Sliced From IngotIngot

Pullingdirection

solid-liquidinterface

Cristallinesolid film

Fusedsilicon

Crucible

Edge Film Growth (EFG)Edge Film Growth (EFG)

FURNACEQUARTZTUBE

DOPINGGAS EXHAUST

WAFERS

Doping of the WafersDoping of the Wafers

n p

frontContact

BackContact

Antireflectionfilm

Electric Contact on the Electric Contact on the CellCell

nt m

4

t

Silicon

SiO2

Anti-reflection Solutions Anti-reflection Solutions (1)(1)

AIR

SILICON

o

R

R(1-R)

(1-R)

R2

o

o

o

o

Junction

Anti-reflection Solutions Anti-reflection Solutions (2)(2)

Aluminum frame

Sealing gasket

EVA Glass

Glass

SpacerCell

Encapsulation of the PanelEncapsulation of the Panel

D1 D1 D1 D1

By-pass DiodeBy-pass Diode

Current (mA)

Voltage (v)

ISC

Parallel ConnectionParallel Connection

Current (mA)

Voltage (v) VOC

Series ConnectionSeries Connection

Current (mA)

Voltage (v)VOC

ISC

Series-Parallel ConnectionSeries-Parallel Connection

I Characteristicof the twocells mountedin parallel

I-V characteristicof each individualcell

1

2

2I

I

+I

-I

sc

sc

V

Cells in Parallel with Cells in Parallel with Different VDifferent VOCOC

Characteristicof each cell

Characteristicof the twocells mountedin series

Current

Voltage

2vv+vi-vi

A1

2

oc oc0

Cells in Series with Different Cells in Series with Different IISCSC

Ec

Ef

Ev

1.8 eVpi

n

Amorphous Silicon CellsAmorphous Silicon Cells

Ec

Ef

Ev

1.2 eV

2.4 eV

CdS

Cu S2

CdS/Cu2S CellsCdS/Cu2S Cells

E c E f

E v

1.5 eV

2.4 eV

n-CdS

p-CdTe

CdS/CdTe CellsCdS/CdTe Cells

Ec

Ef

Ev1.43 eV

Distance

Energy

GaAsGaAlAs

GaAlAs/GaAs CellsGaAlAs/GaAs Cells

C2

0 Watt price

Line of theminimum efficiency (cmin)

Row materialcost

Profitabilitylimit line

21 CF

PC

l

oc

P

Cost EffectivenessCost Effectiveness

C2 0

Watt price

Line of theminimum efficiency (cmin)

Row materialcost

Profitabilitylimit line

P

)( 21 CCF

Poc

l

Importance of the Importance of the EfficiencyEfficiency

0

200

400

600 ENCAPSULATION

FABRICATION

SLICING

MONOCRISTAL PULLING

DECOMPOSITION OF HALIDES

SiHCl DISTILL. 3

ARC FURNACE

kWh/m 2

Lostmaterial

Energetic Pay BackEnergetic Pay Back