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stress by agents transported via the atmosphere such as dust, sand, salty mist and
other agents;
moisture originating from rain, dew and frost;
humidity originating from the atmosphere;
irradiance consisting of direct and indirect irradiance from the Sun; mainly the
highlyenergetic UV radiation is challenging for many materials.
Modules are qualified and type-approved according to IEC 61215 [107] for modules
based on crystalline silicon solar cells and IEC 61646 [108] for thin-film modules. The
aim of both IEC 61215 and IEC 61646 is to judge, within reasonable time and costs,
whether modules are suitable for long term operation, experiencing the stresses mentioned
above. Since the modules cannot be tested during a period of many years, accelerated
stress testing must be used. The required tests are [109]:
Thermal cycles for studying whether thermal stress leads to broken interconnects,
broken cells, electrical bond failure, or adhesion of the junction box.
Damp heat testing to see whether the modules suffer from corrosion,
delamination, loss of adhesion and elasticity of the encapsulant, or adhesion of
the junction box.
Humidity freeze testing in order to test delamination, or adhesion of the junction
box.
UV testing, because UV light can lead to delamination, loss of adhesion and
elasticity of the encapsulant, or ground fault due to backsheet degradation.
Mainly, UV light can lead to a discolouration of the encapsulant and back sheet,
which means that they turn yellow. This can lead to losses in the amount of light
that reaches the solar cells.
Static mechanical loads in order to test whether strong winds or heavy snow
loads lead to structural failures, broken glass, broken interconnect ribbons or
broken cells.
Dynamic mechanical loads, which can lead to broken glass, broken interconnect
ribbons or broken cells.
Hot spot testing in order to see whether hot spots due to shunts in cells or
inadequate bypass diode protection are present.
Hail testing to see whether the module can handle the mechanical stress induced
by hail.
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stress by agents transported via the atmosphere such as dust, sand, salty mist and
other agents;
moisture originating from rain, dew and frost;
humidity originating from the atmosphere;
irradiance consisting of direct and indirect irradiance from the Sun; mainly the
highlyenergetic UV radiation is challenging for many materials.
Modules are qualified and type-approved according to IEC 61215 [107] for modules
based on crystalline silicon solar cells and IEC 61646 [108] for thin-film modules. The
aim of both IEC 61215 and IEC 61646 is to judge, within reasonable time and costs,
whether modules are suitable for long term operation, experiencing the stresses mentioned
above. Since the modules cannot be tested during a period of many years, accelerated
stress testing must be used. The required tests are [109]:
Thermal cycles for studying whether thermal stress leads to broken interconnects,
broken cells, electrical bond failure, or adhesion of the junction box.
Damp heat testing to see whether the modules suffer from corrosion,
delamination, loss of adhesion and elasticity of the encapsulant, or adhesion of
the junction box.
Humidity freeze testing in order to test delamination, or adhesion of the junction
box.
UV testing, because UV light can lead to delamination, loss of adhesion and
elasticity of the encapsulant, or ground fault due to backsheet degradation.
Mainly, UV light can lead to a discolouration of the encapsulant and back sheet,
which means that they turn yellow. This can lead to losses in the amount of light
that reaches the solar cells.
Static mechanical loads in order to test whether strong winds or heavy snow
loads lead to structural failures, broken glass, broken interconnect ribbons or
broken cells.
Dynamic mechanical loads, which can lead to broken glass, broken interconnect
ribbons or broken cells.
Hot spot testing in order to see whether hot spots due to shunts in cells or
inadequate bypass diode protection are present.
Hail testing to see whether the module can handle the mechanical stress induced
by hail.