Solar Cell Encapsulant Resin Composition for PID Suppression
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Solution Overview
Problem
Solar cell modules experience potential-induced degradation (PID) and air bubble formation due to insufficient volume resistivity in existing encapsulating materials, leading to decreased performance and reliability.
Innovation Solution
A crosslinkable resin composition for encapsulating materials with specific acetone-absorbing ratios and volume resistivity ranges, optimized through crosslinking treatment, to suppress PID and air bubble generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an ethylene/vinyl acetate copolymer is used as encapsulating material, then transparency, flexibility, and adhesiveness are improved, but volume resistivity is insufficient and decomposition products affect solar cell elements
Solution Approach 1:
The patent uses a composite material consisting of ethylene/α-olefin copolymer and ethylene functional group-containing monomer copolymer. This combination allows the material to maintain good adhesiveness while achieving sufficiently high volume resistivity to prevent PID phenomenon, resolving the contradiction between adhesiveness and electrical insulation properties.
Solution Approach 2:
The patent changes the chemical composition parameters by selecting specific copolymer types (ethylene/α-olefin and ethylene functional group-containing monomer) with controlled functional groups. This parameter adjustment enables the material to achieve both required adhesiveness and volume resistivity without using ethylene/vinyl acetate copolymer.
2Loss of energy
If system voltage is increased to decrease transmission loss, then energy efficiency is improved, but potential difference between frame and cell increases causing PID phenomenon
Solution Approach 1:
The encapsulating material acts as an intermediary between the solar cell element and the frame. By having sufficiently high volume resistivity, it mediates the electrical potential difference, preventing charge accumulation and PID phenomenon while allowing the system to operate at high voltages for reduced transmission loss.
3Temperature
If organic peroxide is added to achieve crosslinking, then heat resistance is improved, but air bubble formation occurs due to decomposition
Solution Approach 1:
The patent changes the chemical structure parameters by using ethylene/α-olefin copolymer and ethylene functional group-containing monomer copolymer with specific functional groups. This allows achieving crosslinking and heat resistance while controlling decomposition behavior to minimize air bubble formation during the curing process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents PID and air bubble formation, enhancing the long-term reliability and performance of solar cell modules by maintaining high volume resistivity and adhesion properties.
Implementation Method 1
When the encapsulating material for solar cell is immersed in acetone at 23° C. for one hour after a crosslinking treatment
Implementation Method 2
an encapsulating material for solar cell which is made of a resin composition containing a crosslinkable resin and satisfies the following 1) and 2) 1) When the encapsulating material for solar cell is immersed in acetone... an acetone-absorbing ratio is in a range of 3.5 weight % to 12.0 weight %
Implementation Method 3
a crosslinking treatment in which the encapsulating material for solar cell is heated and depressurized at 150° C. and 250 Pa for three minutes, and then is heated and pressurized at 150° C. and 100 kPa for 15 minutes
Implementation Method 4
heated and depressurized at 150° C. and 250 Pa for three minutes, and then is heated and pressurized at 150° C. and 100 kPa for 15 minutes
Implementation Method 5
a volume resistivity of the above-described crosslinking-treated encapsulating material for solar cell... is in a range of 1.0×10^13 Ω·cm to 1.0×10^18 Ω·cm
Data Source
AI summary
An encapsulating material for solar cell is made of a resin composition containing a crosslinkable resin, and satisfies the following 1) and 2). 1) When the encapsulating material for solar cell is immersed in acetone at 23° C. for one hour after a crosslinking treatment in which the encapsulating material for solar cell is heated and depressurized at 150° C. and 250 Pa for three minutes, and then is heated and pressurized at 150° C. and 100 kPa for 15 minutes, an acetone-absorbing ratio is in a range of 3.5 weight % to 12.0 weight % with respect to the weight of the above-described crosslinking-treated encapsulating material for solar cell. 2) A volume resistivity of the above-described crosslinking-treated encapsulating material for solar cell, which is based on JIS K6911 and measured at a temperature of 100° C. with an applied voltage of 500 V, is in a range of 1.0×1013 Ω·cm to 1.0×1018 Ω·cm.