Primary components of facility are test chamber and external solar simulator. Voltage--current performance characteristics of solar cells at various combinations of temperature and light intensity are plotted on X-Y recorder. Data are fed into computer for calculation of maximum power, curve shape factor, cell efficiency, and averages of each parameter

Yasui, R. K.

English

NASA Technical Reports Server

A%lgust 1974
	
B74-10099 
NASA TECH BRIEF S	 NASA Pasadena Office 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
-.	 -=	 - ------------
Facility for Testing Solar Cells 
A test facility has been developed for evaluating 
the performance characteristics of solar cells over a 
temperature range of —180° to +200°C in vacuum 
or in a gas. Primary components of the facility are a 
test chamber and an external solar simulator. The 
test chamber is 33 cm high and 38 cm in diameter; 
light from the solar simulator passes through a 20-cm 
circular quartz window in a wall of the test chamber. 
Tests at temperatures below 10°C are conducted in 
a vacuum or in an atmosphere of dry nitrogen to 
prevent condensation of water vapor on the surfaces 
. of the solar cells. 
The solar cells are mounted within the chamber on 
a block of copper which acts as a heat sink; the block 
is bored to provide channels for the circulation of 
liquid nitrogen and to form compartments between 
the channels for cartridge-type heaters. Eight thermo-
couples are set in position on the block; six are sit-
uated so as to indicate temperature gradients within 
the block and two are used to indicate the temper-
ature of the solar cells. Temperatures are monitored 
continuously to ensure proper control of the set-
point temperature and to ensure that thermal changes 
do not exceed 5°C per minute. 
A calil5rated intensity-standard cell and a color 
ratio detector are located in the chamber over the 
copper block; these devices are isolated thermally 
and electrically from the copper block and are main- 
tained at a constant temperature by a thermoelectric 
module which is mounted on a separate, water-cooled 
heat sink.
The solar simulator is a close-filtered xenon system; 
intensities in the range of 5 to 300 mW/cm 2 are ob-
tained by interposing neutral density filters in the 
light path and by varying the distance from the 
source to the test chamber. The uniformity of light 
intensity over the test area is within ±2%. The color 
ratio detector assures that the spectral quality of the 
solar simulator is constant for all temperature tests 
of the electrical performance of solar cells. 
The voltage—current performance characteristics 
of solar cells at various combinations of temperature 
and light intensity are plotted on an X-Y recorder. 
Data from the plots are fed into a computer for cal-
culation of maximum power, curve shape factor, cell 
efficiency, and the averages of each of the parameters. 
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
NASA Pasadena Office 
4800 Oak Grove Drive 
Pasadena, California 91103 
Reference: TSP74-1 0099 
Patent status: 
NASA has decided not to apply for a patent. 
Source: Robert K. Yasui of 
Caltech/JPL 
under contract to 
(NPO-11761) 
Category 02 
.
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19740000099 2020-03-17T14:05:09+00:00Z


Facility for testing solar cells

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