1. Photovoltaic Systems Engineering
SEC598
Photovoltaic Systems Engineering
(SEC501 Solar Engineering and Commercialization, I)
Session 05
Solar Cells, Part 1
August 31, 2017

2. Session 05 Components
PV System Components
Overview
Solar cells

3. Learning Outcomes Introduction to solar energy system components
Introduction to operation of solar cells

4. PV System: Definition
A photovoltaic system (or PV system) is an engineered system that carries out these operations:
Absorption of incident solar radiation
Conversion of the absorbed solar energy to DC electrical energy
Controlled transfer of the DC electrical energy to a storage device (such as an array of batteries) OR
Controlled inversion of the DC electrical energy to AC electrical energy
Controlled transfer of the electrical energy to electrical loads or to the electrical grid

5. PV System Configurations
A simplified version of a “stand-alone” system
that transfers DC electrical energy to a storage device

6. PV System Configurations
A simplified version of a “grid-tied”system
that inverts the DC electrical energy to AC
electrical energy and transmits that energy
to the national grid

7. Solar Energy Conversion
Optical Energy is the energy contained in light; Optical Power is the rate at which optical energy is delivered
Electrical Energy is the energy contained in electrons and other charged particles; Electrical Power is the rate at which electrical energy is delivered to an “electrical load”
Electrical Power is calculated by multiplying the Electrical Current and the Electrical Voltage in the electrical device
Current is a measure of the flow of electrons (amperes)
Voltage is a measure of the potential energy (volts)

8. PV System Components - Solar Cells
The electrical “device” that converts optical energy to electrical energy is the Solar Cell. The solar cell is a semiconductor device invented in 1954 at Bell Telephone Laboratories by Russell Ohl:
The vast majority of solar cells are made from silicon. And this is remarkable good fortune, since silicon is the third most abundant element on earth!!

9. PE vs PV

10. Key Points for Photovoltaic Operation
The solar cell absorbs optical radiation
The absorption produces energetic charged particles
The particles can be transported through the Solar Cell and into an external circuit before they are lost

11. Elements and Crystallinity

12. The Bonding Model
Pierret

13. The Band Model
Pierret

14. A simplified picture of the band model
Pierret

15. Electrons and Holes
Pierret

16. Another look at the Periodic Table

17. The Doping Model
Pierret

18. Resources
Jenny Nelson, The Physics of Solar Cells, Imperial College Press, 2003
Robert F. Pierret, Semiconductor Fundamentals, V.1., Modular Series on Solid State Devices, Addison-Wesley, 1988
Gerold W. Neudeck, The PN Junction Diode, V.2., Modular Series on Solid State Devices, Addison-Wesley, 1989