Multilayered PV Module Backsheet Primer Adhesion

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Solution Overview

Problem

Existing photovoltaic module backsheets face challenges with moisture barrier properties, durability, and adhesive strength, particularly due to complex manufacturing methods and high processing temperatures, which affect long-term reliability and productivity.

Innovation Solution

A multi-layered film comprising a barrier film, a primer layer with a copolymer compatible with fluoropolymers, and a fluoropolymer coating layer, where the primer layer includes functional groups formed by copolymerization with silane, titanium, zirconium, or aluminum-based coupling agents, enhancing adhesive strength and moisture resistance, and can be processed at low temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a triple-layered structure with PVF film stacked on both surfaces of PET film is used to achieve excellent weather resistance and durability, then the backsheet can protect the photovoltaic cell for 25 years or more, but the manufacturing method becomes complicated and vulnerable to moisture

Engineering Contradiction:
Improveweather resistanceVSAvoidmanufacturing method complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The backsheet is divided into multiple functional layers: a base layer (PET or other polymer film), a fluoropolymer layer for weather resistance, and a primer layer for adhesion. This segmentation allows each layer to perform its specific function optimally while simplifying the overall manufacturing process compared to the traditional triple-layered PVF-PET-PVF structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite material structure combining different polymers and fluoropolymers with specific properties. The base layer provides mechanical strength, the fluoropolymer layer provides UV and weather resistance, and the primer layer ensures strong adhesion between layers, creating a composite material system that achieves excellent durability with simpler manufacturing.

Inventive Principle:
Principle #40Composite materials

2Reliability

If fluoropolymer films such as PVDF, CTFE or ECTFE are used instead of PVF film to improve weather resistance, then the backsheet exhibits better durability, but the adhesive strength becomes poor

Engineering Contradiction:
ImprovedurabilityVSAvoidadhesive strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

A primer layer is introduced as an intermediary between the base layer and the fluoropolymer layer. This primer layer contains adhesion promoters or coupling agents that enhance the bonding between the base layer and the fluoropolymer layer, solving the poor adhesion problem inherent in fluoropolymer-based backsheets while maintaining their excellent weather resistance and durability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If high processing temperatures are used to ensure proper bonding and curing of the backsheet layers, then the adhesive strength and durability are improved, but thermal deformation and manufacturing costs increase

Engineering Contradiction:
Improveadhesive strengthVSAvoidprocessing temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The invention modifies the chemical and physical parameters of the primer layer and fluoropolymer composition to enable low-temperature processing. This includes using adhesion promoters with lower curing temperatures, adjusting molecular weight and composition of polymers, and optimizing cross-linking mechanisms that occur at reduced temperatures, thereby preventing thermal deformation while maintaining strong adhesion.

Inventive Principle:
Principle #35Parameter changes

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 photovoltaic module with improved moisture resistance, weather resistance, and adhesive strength, reducing manufacturing costs and preventing thermal deformation, while ensuring long-term durability and reliability.

Implementation Method 1

the copolymer having compatibility with the fluoropolymer contains a functional group formed by copolymerization with a silane coupling agent, a titanium-based coupling agent, a zirconium-based coupling agent, or an aluminum-based coupling agent

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

a fluoropolymer coating layer formed on the primer layer

Methodology Applied
Scientific EffectCoating deposition: Deposition (physical)

Implementation Method 3

a barrier film, a primer layer formed on the barrier film... excellent moisture resistance

Methodology Applied
Scientific EffectMoisture barrier: Permeation

Data Source

PatentEP2813540B1Multilayered film and method for manufacturing same
Publication Date: 2020.01.15 LG CHEM LTD
  • EP2813540B1 patent drawingFigure 1~3

AI summary

A multi-layered film, a method of preparing the same and a photovoltaic module are provided. A barrier film having excellent moisture barrier properties can be coated with a fluoropolymer having excellent weather resistance by means of a primer layer including a silane-modified acrylic copolymer, and an interfacial adhesive strength can also be ensured. As a result, a multi-layered film having excellent durability and weather resistance and simultaneously exhibiting a high interfacial adhesive strength to the barrier film can be provided. In preparation of the multi-layered film, the manufacturing cost can also be reduced, productivity can be enhanced, and degradation of product qualities caused by thermal deformation or thermal shock can be prevented. Therefore, the multi-layered film can be effectively used as a backsheet for various photovoltaic modules.