Silicon Solar Modules - Panasonic BP-5917C40 Technical Handbook

9. SILICON SOLAR MODULES

High conversion efficiency and long-term reliability
9.1. General Information
Crystal system silicon solar modules are attracting
attention through the world today primarily as high-
efficiency solar cells. This is because high-efficiency
solar modules are capable of converting the radiant
energy of sunlight directly into electrical energy which
is easy to use. Panasonic began marketing crystal silicon
solar modules and solar power supply systems in 1963.
We have continued to develop them for use in every
field, from the home to industry, improving their
performance and reliability while reducing their cost.
We have developed a variety of outdoor power supply
devices for observation, water discharge warning
stations and radio relay stations for dam control. We
have also developed solar clocks which have been
installed in more than 4,300 locations worldwide. Our
latest research and streamlined design systems are
highly regarded in many fields all over the world. This is
because our work is based on field data from over 10
years in a wide variety of solar battery utilization fields.
9.2. Features
High in performance with a module using silicon
•
cells.
Superb reliability and long-lasting durability to meet
•
the operating conditions in various natural
environments.
The place where the P-type and N-type meet is called a
P-N junction. It constitutes the heart of the solar cell and
plays the most important role in the conversion of light
to electricity. The solar cell consists of the P-N junction
with electrodes on either side of it forming a grid, as
well as electrodes on the back surface. To briefly
explain the principle whereby electricity is generated,
light from the sun shines on the silicon and its energy is
absorbed by the crystal.
9.5. Specifications
Model No.
Number
Cell size
of cells
BP-K36KS 100mm
BP-HK36K 100mm/2
36
BP-QK36H 100mm/4
BP-EK36 100mm/8
BP-STK36 100mm/16
Panasonic
Structure
Dimensions
Weight
(mm)
Voltage
(kg)
W L H
448 988 36 5.9
445 535 36 3.2
DC12V
350 340 30 2.0
222 278 30 1.2
187 201 30 0.7
Solar Cells Handbook, Page 28
9.3. Applications
Independent power supply systems for radio relay
•
stations, measuring systems, etc.
Large-scale solar power generation systems linked
•
with commercial power.
9.4. Structure and Electricity Generation Principle of
Silicon Solar Cells
Solar cells use the photovoltaic effect of semiconductors
to convert light energy from the sun directly into
electrical energy. They do not store electricity. Most
silicon solar cells have a structure similar to that shown
in the diagram below. They consist of a sheet of silicon
called a P-type (approximately 0.4mm thick) with a
second, thinner (1-2 µm) layer called a N-type on top of
it.
Grid electrode ( - )
1.5 m
Back surface
electrode (+)
P-type silicon substrate
+
n diffusion layer
Electrons involved in forming the bonds between atoms
fly out from the crystalline framework as free electrons
bearing a negative charge. After the electrons have been
given off, a positive electron hole is formed. An
electrical field builds up inside the silicon present at the
P-N junction and the electrons are scattered to the N-
type silicon. A voltage is produced at both electrodes
and, if a load is connected to them, electrical power is
supplied to it.
Absolute- maximum ratings
Open--
Operating Storage
Circuit
temperature temperature
Voltage
Topr Tstg
Voc (V)
21.5
20.7
-40 ~ +90 °C -40 ~ +90 °C
21.0
21.0
20.8
Condition : Sunlight intensity at 1.0kW/m
Current
Anti-reflective coating
Electro-optical characteristics
Maximum
Optimum Short-- Optimum--
power (W) P
Operating circuit operating
voltage current current
min.
Vpm (V) Isc (A) 1pm (A)
16.9 3.35 3.20 51.4
16.7 1.55 1.44 21.6
16.8 0.78 0.68 11.7
16.8 0.39 0.33 5.1
16.6 0.19 0.17 2.5
2
Cell temperature at 25°C AM=1.5
0.4mm
Conversion
efficiency
max
(%)
typ
54.1 15.0
24.0 13.0
13.0 16.0
5.6 12.4
2.8 12.4
August 1998