EVA Solar Sealing Film Acid Acceptor Corrosion Prevention
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Solution Overview
Problem
Solar cells face durability issues due to corrosion of conducting wires and electrodes caused by moisture and acetic acid generated from ethylene-vinyl acetate copolymer sealing films, which also affect photovoltaic performance when acid acceptors are used to prevent rust.
Innovation Solution
A sealing film comprising ethylene-vinyl acetate copolymer, a cross-linking agent, and an acid acceptor is used on the light receiving surface, with optimized particle size and concentration of the acid acceptor to prevent corrosion without reducing photovoltaic performance, and a similar film with higher acid acceptor content is used on the rear surface to enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a colorless transparent EVA film is used as the sealing film to maintain high transparency and light transmission, then photovoltaic performance is improved, but the film generates acetic acid through moisture permeation at high temperature, which accelerates rust formation and reduces durability
Solution Approach 1:
An acid acceptor is introduced as an intermediary substance within the EVA sealing film to neutralize acetic acid generated during aging. The acid acceptor acts as a mediator between the EVA matrix and the photovoltaic elements, preventing direct contact between corrosive acetic acid and metal components while maintaining the film's optical transparency and sealing function.
Solution Approach 2:
The sealing film is designed as a composite material system consisting of EVA base resin, cross-linking agent for enhanced stability, and acid acceptor particles dispersed throughout the matrix. This composite structure combines the optical benefits of transparent EVA with the corrosion protection of acid-absorbing components, achieving both high light transmission and improved durability.
2Reliability
If the amount of acid acceptor in the sealing film is increased to prevent rust formation, then durability is improved, but the photovoltaic performance is reduced due to decreased transparency and increased light reflection/absorption
Solution Approach 1:
The patent optimizes the concentration parameter of acid acceptor within a specific range (0.1-5.0 wt%, preferably 0.5-2.0 wt%) to balance durability improvement with light transmission maintenance. By precisely controlling this parameter, the acid acceptor provides sufficient corrosion protection while minimizing its impact on optical properties. Additionally, the particle size is controlled (0.1-5.0 μm) to reduce light scattering.
3Object-affected harmful factors
If a glass plate is used as the transparent light receiving surface protection member to prevent moisture permeation, then water resistance is improved, but the durability against rust cannot be sufficiently improved because acetic acid can still reach the electrodes through other pathways
Solution Approach 1:
The acid acceptor is strategically positioned within the EVA sealing film layers that directly contact the photovoltaic elements and conducting wires, creating localized corrosion protection zones where it is most needed. The acid acceptor concentration is optimized in the sealing film composition to specifically address rust prevention at critical interfaces between the sealing material and metal components.
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 prevents corrosion and maintains photovoltaic performance over a long period by optimizing the acid acceptor's particle size, composition, and placement, ensuring the solar cell's durability and efficiency.
Implementation Method 1
a sealing film for solar cell which comprises an acid acceptor
Implementation Method 2
cross-linked the EVA by heating and pressing to unify the superposed product
Implementation Method 3
A solar cell has been paid attention as a device directly converting solar energy into electric energy
Data Source
AI summary
Sealing film for solar cell which prevents conducting wires and electrodes of the solar cell from rusting and thereby enable the solar cell to retain its high photovoltaic performance for a long period. A light receiving surface sealing film for solar cell comprising ethylene-vinyl acetate copolymer, a cross-linking agent and an acid acceptor. A rear surface sealing film for solar cell comprising ethylene-vinyl acetate copolymer, a cross-linking agent and an acid acceptor, wherein the acid acceptor is contained in the range of not less than 0.5 parts by weight based on 100 parts by weight of ethylene-vinyl acetate copolymer.