Solar Cell Encapsulating Material to Prevent Bubbles and Acid Gas
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Solution Overview
Problem
Existing encapsulating materials for solar cells, such as EVA compositions, risk affecting solar cell elements with acetic acid gas and have limitations in properties like transparency, flexibility, and crosslinking characteristics, while polyolefin compositions struggle to balance these properties and often generate bubbles during the lamination process.
Innovation Solution
An encapsulating material containing an ethylene/α-olefin copolymer with specific MFR and Shore A hardness, combined with an organic peroxide of peroxyketals having a 1-hour half-life temperature between 100 to 135 degrees Celsius, to achieve excellent transparency, flexibility, adhesiveness, and crosslinking characteristics, reducing bubble formation during manufacturing and long-term usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If EVA composition is used as encapsulating material, then transparency and flexibility are improved, but acetic acid gas is generated affecting solar cell elements
Solution Approach 1:
The patent changes the chemical composition parameters by using ethylene/α-olefin copolymer instead of EVA, and selects organic peroxide with specific 1-hour half-life temperature range (100-135°C) to eliminate acetic acid gas generation while preserving transparency and flexibility properties
Solution Approach 2:
The patent employs organic peroxide as a temporary crosslinking agent that decomposes completely after serving its function during lamination, leaving no harmful residues like acetic acid gas, thus replacing the harmful EVA system with a cleaner alternative
2Object-generated harmful factors
If polyolefin composition is used to avoid acetic acid gas, then harmful factors are reduced, but transparency and flexibility deteriorate
Solution Approach 1:
The patent optimizes the copolymer composition parameters (ethylene content 60-90 mol%, α-olefin content 10-40 mol%) and molecular weight characteristics (MFR 1-50 g/10min) to achieve the right balance between transparency, flexibility, and resistance to acetic acid gas
Solution Approach 2:
The patent creates a composite system combining ethylene/α-olefin copolymer with organic peroxide crosslinking agent, where the copolymer provides the base matrix with good transparency and the peroxide provides crosslinking for enhanced mechanical properties without sacrificing optical properties
3Strength
If crosslinking efficiency is improved using silane coupling agent, then adhesiveness is enhanced, but bubble formation occurs during lamination
Solution Approach 1:
The patent changes the crosslinking mechanism by using organic peroxide instead of silane coupling agents, and controls the 1-hour half-life temperature of the peroxide to match the lamination process temperature, enabling uniform crosslinking without bubble formation
Solution Approach 2:
The patent replaces the moisture-cured silane crosslinking mechanism with a thermal decomposition crosslinking mechanism using organic peroxide, which provides more predictable and uniform crosslinking behavior during the lamination process, eliminating bubble formation issues
4Ease of operation
If MFR is increased to improve flexibility, then processability is enhanced, but crosslinking characteristics deteriorate
Solution Approach 1:
The patent optimizes the MFR parameter within a specific range (1-50 g/10min at 190°C, 2.16 kg load) and compensates for lower crosslinking efficiency by controlling the organic peroxide concentration (0.1-5 phr) and its 1-hour half-life temperature to ensure adequate crosslinking while maintaining flexibility
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 provides a balanced set of properties for the encapsulating material, ensuring economic efficiency and maintaining the appearance of solar cell modules without bubble formation, while enhancing adhesion and heat resistance.
Implementation Method 1
an encapsulating material for solar cell, a method for producing an encapsulating material for solar cell and a solar cell module... An encapsulating material containing an ethylene/α-olefin copolymer with specific MFR and Shore A hardness, combined with an organic peroxide of peroxyketals having a 1-hour half-life temperature between 100 to 135 degrees Celsius, to achieve excellent transparency, flexibility, adhesiveness, and crosslinking characteristics
Data Source
Figure 1
Figure 2(A)~2(B)
AI summary
An encapsulating material for solar cell containing an ethylene/α-olefin copolymer satisfying the following a1) and a2), and a specific peroxyketal having a 1-hour half-life temperature in a range of 100 to 135 degrees centigrade; the peroxyketal being contained in an amount of 0.1 to less than 0.8 weight parts relative to 100 weight parts of the ethylene/α-olefin copolymer. a1) the shore A hardness is from 60 to 85 as measured in accordance with ASTM D2240. a2) MFR is from 2 to 50 g/10 minutes as measured under the conditions of a temperature of 190 degrees centigrade and a load of 2.16 kg in accordance with ASTM D1238