Solar Battery Encapsulating Sheet Set for PID Suppression
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Solution Overview
Problem
Solar battery modules experience potential-induced degradation (PID) due to high voltage differences between the frame and cell, leading to decreased output and deteriorated characteristics, while existing encapsulating sheets fail to adequately suppress air bubble generation and peeling/cracking issues.
Innovation Solution
A sheet set for encapsulating solar batteries is developed, comprising a first encapsulating sheet with high volume resistivity and a second sheet containing polar groups, subjected to specific heating and pressurization treatments to enhance volume resistivity and absorb decomposed organic peroxides, thereby suppressing PID and air bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an encapsulating sheet with high content of ethylene/vinyl acetate copolymer is used, then air bubble generation is suppressed, but volume resistivity is insufficient and PID phenomenon cannot be suppressed
Solution Approach 1:
The patent uses a composite resin composition containing ethylene/α-olefin copolymer (50-95 mass%), ethylene functional group-containing monomer copolymer (5-50 mass%), and organic peroxide (0.1-5 mass%). This composite structure combines the air bubble suppression capability of ethylene-based polymers with the high volume resistivity provided by the functional group-containing copolymer, resolving the contradiction between suppressing air bubbles and maintaining high volume resistivity to prevent PID phenomenon.
Solution Approach 2:
The patent modifies the chemical composition parameters of the encapsulating sheet by incorporating specific ratios of ethylene/α-olefin copolymer and ethylene functional group-containing monomer copolymer. By adjusting the mass% composition within specified ranges and controlling the organic peroxide content, the material achieves both low air bubble generation and high volume resistivity, transforming the material properties to simultaneously address both requirements.
2Reliability
If an encapsulating sheet with high content of ethylene functional group-containing monomer copolymer is used, then volume resistivity is improved, but air bubble generation increases and peeling/cracking occurs
Solution Approach 1:
The patent creates a balanced composite material where ethylene/α-olefin copolymer (providing low air bubble generation) is combined with ethylene functional group-containing monomer copolymer (providing high volume resistivity). The specific composition ratio ensures that neither component dominates, achieving a synergistic effect that suppresses both air bubbles and maintains high volume resistivity, preventing the peeling and cracking issues associated with high functional monomer content.
Solution Approach 2:
The patent optimizes the compositional parameters by limiting the ethylene functional group-containing monomer copolymer to 5-50 mass% and ethylene/α-olefin copolymer to 50-95 mass%, with organic peroxide at 0.1-5 mass%. This parameter control ensures sufficient volume resistivity while preventing excessive air bubble generation and peeling/cracking, transforming the material properties to achieve a balanced performance.
3Power
If the system voltage is increased to accommodate larger power generation systems, then power generation capacity is improved, but potential difference between frame and cell increases causing PID phenomenon
Solution Approach 1:
The patent changes the electrical parameter of the encapsulating material by incorporating ethylene functional group-containing monomer copolymer and organic peroxide to achieve high volume resistivity (10^12 Ω·cm or higher). This parameter change in the material's electrical resistance prevents current leakage and PID phenomenon even when the system operates at high voltages required for large-scale power generation systems.
Solution Approach 2:
The patent uses a composite resin system that combines multiple polymers and organic peroxide to create an encapsulating sheet with superior electrical insulation properties. This composite structure provides the high volume resistivity needed to suppress PID phenomenon while maintaining the mechanical and optical properties required for high-voltage solar battery module operation.
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 suppresses PID and air bubble generation, improving the longevity and reliability of solar battery modules by maintaining high volume resistivity and adhesiveness, ensuring stable performance over time.
Implementation Method 1
the second encapsulating sheet has at least one polar group selected from a carboxyl group, an ester group, a hydroxyl group, an amino group, and an acetal group
Implementation Method 2
curing the solar battery encapsulating sheet through crosslinking by heating and pressurizing the laminate
Data Source
AI summary
A sheet set for encapsulating a solar battery including a first encapsulating sheet and a second encapsulating sheet which are disposed between a light-incident surface protective member and a back surface protective member, and are used to encapsulate solar battery elements is provided. When the first encapsulating sheet and the second encapsulating sheet are subjected to a heating and pressurization treatment in which the first encapsulating sheet and the second encapsulating sheet are heated and depressurized under defined conditions, a volume resistivity of the first encapsulating sheet measured under defined conditions, is higher than a volume resistivity of the second encapsulating sheet. The first encapsulating sheet is disposed between the light-incident surface protective member and the solar battery elements. The second encapsulating sheet has at least one polar group selected from a carboxyl group, an ester group, a hydroxyl group, an amino group, and an acetal group.