Ethylene/Alpha-Olefin Copolymer for PID-Resistant Solar Encapsulation
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Solution Overview
Problem
Existing ethylene/alpha-olefin copolymers used in solar cell encapsulants face issues with high power loss due to low volume resistance and potential-induced degradation (PID) under high-voltage conditions, and lack sufficient light transmittance for efficient solar cell operation.
Innovation Solution
An ethylene/alpha-olefin copolymer with a density of 0.85 to 0.89 g/cc, melting temperature of 60 to 90°C, and a Tm - Te value of 35 to 65°C, incorporating 1-butene, 1-hexene, or 1-octene, is developed using specific transition metal compounds as catalysts to achieve high volume resistance and light transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ethylene/vinyl acetate copolymer is used as solar cell encapsulant, then adhesiveness and processability are improved, but volume resistance decreases and acetic acid decomposition occurs
Solution Approach 1:
The patent changes the chemical composition parameters by replacing vinyl acetate units with alpha-olefin units (1-butene, 1-hexene, or 1-octene) in the copolymer structure. This substitution fundamentally alters the material properties: alpha-olefin copolymers maintain good adhesiveness while achieving volume resistance greater than 1×10^15 Ω·cm and eliminating acetic acid decomposition, thus resolving the contradiction between ease of manufacture and reliability
Solution Approach 2:
The patent creates a composite material system by combining ethylene with specific alpha-olefin comonomers (1-butene, 1-hexene, or 1-octene) in controlled ratios. This composite approach allows optimization of both processing properties (adhesiveness) and electrical properties (volume resistance) through tailored composition, achieving volume resistance >1×10^15 Ω·cm while maintaining manufacturability
2Loss of energy
If system voltage is increased to reduce transmission loss, then energy efficiency is improved, but potential-induced degradation (PID) increases
Solution Approach 1:
The patent changes the electrical resistance parameter of the encapsulant material by using alpha-olefin copolymers with specifically controlled composition and molecular structure. This achieves volume resistance greater than 1×10^15 Ω·cm, which provides sufficient electrical insulation to prevent PID even at high system voltages (600-1000 V), thereby allowing energy-efficient high-voltage operation without PID degradation
3Reliability
If ethylene/alpha-olefin copolymer with high volume resistance is used, then PID resistance is improved, but light transmittance may decrease
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: alpha-olefin content (5-50 mol%), comonomer type (1-butene, 1-hexene, or 1-octene), and molecular weight distribution. This multi-parameter optimization achieves the difficult balance of volume resistance >1×10^15 Ω·cm while maintaining light transmittance greater than 90% at 500 nm wavelength, resolving the contradiction between electrical insulation and optical transparency
Data Source
AI summary
The present invention relates to an ethylene/alpha-olefin copolymer having excellent volume resistance and light transmittance, and a method for preparing the same.