Functionalized Polyolefin Encapsulant Film for PV Moisture Barrier
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Solution Overview
Problem
Conventional polymeric materials used in photovoltaic modules, such as ethylene-vinyl acetate copolymers, suffer from low volume resistivity, moisture barrier properties, and chemical degradation under sunlight exposure, which affects the module's performance and safety.
Innovation Solution
A film comprising a functionalized polyolefin polymer, specifically propylene copolymers, terpolymers, or ethylene terpolymers, with controlled monomer compositions and low inorganic metal oxide content, providing high electrical resistance, excellent adhesion, moisture and gas barrier properties, and ease of processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If EVA copolymer is used as encapsulant, then adhesion property is improved, but volume resistivity and moisture barrier properties deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the encapsulant material from EVA copolymer to polyolefin elastomer with specific functional groups. This parameter change resolves the contradiction by providing a material that simultaneously achieves high adhesion (through functional group interaction) and high volume resistivity (through polyolefin's inherent properties) along with excellent moisture barrier properties.
Solution Approach 2:
The patent employs composite material design by combining polyolefin elastomer base material with specific functional groups (carboxylic acid, hydroxyl, amine, or isocyanate groups). This composite approach allows the material to exhibit both the high electrical resistance and moisture barrier of polyolefin and the strong adhesion of polar functional groups, resolving the technical contradiction.
2Ease of manufacture
If EVA copolymer is used as encapsulant, then ease of processing is improved, but chemical stability under sunlight deteriorates
Solution Approach 1:
The patent changes the chemical structure parameter from EVA copolymer to polyolefin elastomer with functional groups. This parameter change resolves the contradiction because polyolefin's saturated carbon backbone provides superior UV resistance and chemical stability compared to EVA, while the functional groups maintain ease of processing and bonding capabilities.
3Reliability
If polyolefin is used as encapsulant, then volume resistivity and moisture barrier properties are improved, but adhesion property deteriorates
Solution Approach 1:
The patent introduces functional groups (carboxylic acid, hydroxyl, amine, or isocyanate) as a parameter change to the polyolefin structure. This resolves the contradiction by adding polar character to the otherwise non-polar polyolefin, enabling strong adhesion through hydrogen bonding or chemical reactions while preserving the high volume resistivity and moisture barrier properties of the polyolefin backbone.
Solution Approach 2:
The patent creates a composite material system where polyolefin elastomer serves as the base matrix providing electrical and moisture barrier properties, while embedded functional groups provide adhesion functionality. This composite structure resolves the contradiction by combining the advantages of both non-polar polyolefin and polar adhesive groups.
4Reliability
If functionalized polyolefin is used as encapsulant, then adhesion property and volume resistivity are improved, but device complexity increases
Solution Approach 1:
The patent makes a targeted parameter change by selecting specific functional groups (carboxylic acid, hydroxyl, amine, or isocyanate) with defined concentration ranges (0.1-10 mmol/g). This focused parameter specification resolves the contradiction by achieving high adhesion and volume resistivity through controlled functionalization rather than complex multi-component systems, thus limiting the increase in device complexity.
Data Source
AI summary
The invention relates to a film comprising a functionalized polyolefin polymer and to the use of the film as an encapsulant film for a photovoltaic module. The functionalized polyolefin polymer is a polymer selected from: (a) a propylene copolymer, (b) a propylene terpolymer, (c) an ethylene terpolymer, and (d) a polymer mixture comprising any combination of polymers (a) to (c). Further, the functionalized polyolefin polymer comprises <0.8 wt %, of an inorganic metal oxide such as alumina, based on the total weight of the functionalized polyolefin polymer. The invention further relates to an encapsulated solar cell comprising encapsulant layers comprising the film. The invention further relates to a photovoltaic module comprising the encapsulated solar cell and to a process for making the photovoltaic module.