Polar star

Photovoltaic panels with a polysiloxane gel encapsulant for extreme climate conditions. Designed  for cold artic areas with temperature down to -60 °C and hot desert areas with temperature up to 100°C

The main reason for failures of standard modules with EVA encapsulant in areas with low temperatures (below –30 °C) are cracks of solar cells  and delamination of the EVA film.


Mechanical properties of films based on ethylene-vinyl acetate copolymer (EVA), in particular  a modulus of elasticity (stiffness) very strongly depends on temperature. Thus, when the temperature is lowered from room temperature to -40 0C the modulus value is increased by about factor of 2. The modulus of elasticity of the silicone gel is almost constant in the temperature range from  +100 °C to -60 °C. At a temperature of -60 °C the modulus of elasticity of the silicone gel of about 100,000 times lower than EVA.


The increased rigidity, i.e. reduced ability of the material to compensate the external loads by mobility of fragments of the polymer macromolecules is associated with the phase transition (vitrification) of the EVA polymer at temperature range from –15 °C (red line) to -40 °C. At low temperatures the high modulus (hard) encapsulating material fully conveys the external mechanical load to the fragile solar cells, which lose the mechanical protection.
Furthermore, the low temperature deteriorates adhesion properties of the EVA. It results in delamination of the EVA film from the glass as well as from the rear TPM protective cover. These results were published by experienced researchers in the United States (NREL), Germany (Fraunhofer Institute) and Russia.

In contrast to EVA, the new encapsulating material based on a low modulus polysiloxanes retain their mechanical, adhesion, optical and dielectric properties in a temperature range from minus –60 °C to + 200 °C.



Data at Standard Test Condition (T=25 ℃ AM=1.5 E=1000W/m2)


1 Peak PowerPm 235W
2 Open Circuit Voltage(Voc) 37.0V
3 Short Circuit CurrentIsc 8.2A
4 Maximum Power VoltageVmp 30.7V
5 Maximum Power Current Imp 7.7A
6 Temperature coefficient of the current 0.05%/oC
7 Temperature coefficient of the voltage -0.31%oC
8 Temperature coefficient of the power -0.40%/oC
9 Maximum System Voltage 1.000V
10 Working Temperature -40+110
11 Dimension(AxBxC) 1650x995x50mm
12 Cell Type Monocrystalline
13 Encapsulant Polysiloxane gel
14 J-box, cables & connectors Tyco
15 Quantity & Dimension of Cell 60 pieces 156x156mm
16 Front Glass Type and Thickness Tempered, 4mm 4444mm3.2mm
17 Back Glass Type and Thickness Tempered, 4mm 43.2mm
18 Installation Hole D1 948mm
D2 674mm
Diameter Φ9mm
19 Weight 26kg

Traxle Solar sro, Eliasova 12, CZ 160 00 Praha 6, Czech Republic, EU, info@traxle.com,

www.traxle.com, Tel. +420 774 994 637

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