Solar Cell Module Reactive UV Absorber Diffusion Control
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Solution Overview
Problem
Existing solar cell modules face degradation and discoloration issues due to the diffusion of ultraviolet absorbers from the back-side encapsulation sheet to the light-receiving-side sheet, especially when exposed to high temperatures over time, leading to reduced ultraviolet light transmittance and efficiency.
Innovation Solution
Incorporating a reactive ultraviolet absorber in the back-side encapsulation sheet that forms a reaction product with a resin component, preventing diffusion and maintaining ultraviolet light transmittance to the solar cell, using compounds like 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole and ethylene-polar monomer copolymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an ultraviolet absorber is added to the back-side encapsulation sheet to prevent degradation and discoloration, then durability of the rear protective sheet is improved, but the ultraviolet absorber diffuses into the light-receiving-side encapsulation sheet over time, reducing ultraviolet light transmittance to the solar cell
Solution Approach 1:
The patent extracts the harmful diffusion behavior by using a reactive ultraviolet absorber that chemically bonds to the resin matrix, preventing the migratory diffusion into the light-receiving-side sheet while maintaining the protective function on the back side
Solution Approach 2:
The patent changes the chemical state of the ultraviolet absorber from a free additive to a reaction product with the resin, fundamentally altering its mobility parameter from diffusive to fixed, thereby resolving the contradiction between protection and light transmission
2Object-affected harmful factors
If a high concentration of ultraviolet absorber is used in the back-side encapsulation sheet to effectively block ultraviolet rays and prevent discoloration, then weather resistance is improved, but time-dependent diffusion migration occurs especially at high temperatures, causing amount of ultraviolet light reaching the solar cell to decrease
Solution Approach 1:
The patent applies preliminary action by pre-reacting the ultraviolet absorber with the resin during the encapsulation sheet formation process, creating a chemically bonded structure before the module is exposed to environmental conditions, thereby preventing subsequent diffusion migration
Solution Approach 2:
The patent creates a composite material system where the ultraviolet absorber is chemically integrated with the resin matrix through reaction products, forming a unified structure that combines protection functionality with stable light transmission properties over time
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 solar cell module exhibits enhanced durability, transparency, and flexibility, with high reflectivity retention of ultraviolet light, minimizing output reduction and ensuring long-term efficiency.
Implementation Method 1
the back-side encapsulation sheet contains a reaction product of a reactive ultraviolet absorber and a resin component
Implementation Method 2
the reactive ultraviolet absorber in the back-side encapsulation sheet prevents the diffusion migration of the ultraviolet absorber into the light-receiving-side encapsulation sheet
Data Source
Figure 1
AI summary
Provided is a solar cell module wherein a rear surface protective sheet has excellent long-term durability, and transmissivity of ultraviolet that reaches the solar cell is retained for a long time. This solar cell module is configured by laminating a front surface protective sheet, a light receiving-side sealing sheet, a solar cell element, a rear surface-side sealing sheet, and a rear surface protective sheet in this order. The solar cell module is characterized in that the light receiving-side sealing sheet has a transmissivity of 50 % or more with respect to light having a wavelength of 300 nm, and the rear surface-side sealing sheet contains a reactive ultraviolet absorbent.