Semi‐quantitative temperature accelerated life test (ALT) for the reliability qualification of concentrator solar cells and cell on carriers

Abstract

An adequate qualification of concentrator photovoltaic solar cells and cell-on-carriers is essential to increase their industrial development. The lack of qualification tests for measuring their reliability together with the fact that conventional accelerated life tests are laborious and time consuming are open issues. Accordingly, in this paper, we propose a semi-quantitative temperature-accelerated life test to qualify solar cells and cell-on-carriers that can assure a minimum life when failure mechanisms are accelerated by temperature under emulated nominal working conditions with an activation energy >0.9 eV. A properly designed semi-quantitative accelerated life test should be able to determine if the device under test will satisfy its reliability requirements with an acceptable uncertainty level. The applicability, procedure, and design of the proposed test are detailed in the paper.

Failure analysis on lattice matched GaInP/Ga(In)As/Ge commercial concentrator solar cells after temperature accelerated life tests

“…The solar cells were forward biased in darkness inside the climatic chambers in order to emulate the photogenerated current under nominal working conditions (concentration level). The suitability to use forward bias current to emulate the photogenerated current is explained in [7]. An intensity of the injected current of 3.2 A (the active area of the solar cells was 0.49 cm 2 ) was determined by using our 3D distributed model in order to avoid an electrical overstress that would produce artificial failures, unexpected on real working conditions [5].…”

Reliability of commercial triple junction concentrator solar cells under real climatic conditions and its influence on electricity cost

“…, which does not depend on wind speed as it has been explained in section 2. On the other hand, decreases with wind speed and it has been fitted to a linear relationship, being the wind speed in m/s. Concentration ratio is 820 suns Solar cell efficiency is 35% at 820 suns. Optical efficiency is 85% Reliability parameters of the solar cells under arbitrary typical conditions (5 h per day at T cell = 80 °C) determined in Refs used to evaluate the reliability parameters in real conditions: The of the main failure mechanism is 1.59 eV. The warranty time for 5% of failures at T cell = 80 °C, t w , 80 °C , is 206225 h. Assuming that solar cell is working at 80 °C 5 h per day, this warranty time results in 113 years . …”

“…Reliability parameters of the solar cells under arbitrary typical conditions (5 h per day at T cell = 80 °C) determined in Refs used to evaluate the reliability parameters in real conditions: The of the main failure mechanism is 1.59 eV. The warranty time for 5% of failures at T cell = 80 °C, t w , 80 °C , is 206225 h. Assuming that solar cell is working at 80 °C 5 h per day, this warranty time results in 113 years . …”

Metal diffusion barriers for GaAs solar cells

“…This can be described with the following equation 17 : (1) in which k is the Boltzmann constant, E a the activation energy for the degradation process, T op the regular operation temperature, T acc the accelerated test temperature and t op and t acc the exposure times to the corresponding temperatures. Typically such accelerated life-time testing (ALT) procedures include operational conditions (illumination, electrical bias) 18,19 . In order to exclude additional (i.e.…”