Photovoltaic Module Barrier Layer for Gas Permeation
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Solution Overview
Problem
Photovoltaic modules, especially those using perovskite or organic semiconductor materials, face stability issues due to sensitivity to atmospheric gases like water and oxygen, leading to degradation and reduced lifespan, as existing encapsulation methods are inadequate in blocking corrosive gases such as acetic acid from decomposed EVA materials.
Innovation Solution
A photovoltaic module design incorporating a barrier layer with a water vapor transmission rate less than 10^-2 g/m²/day at 38°C and 85% humidity, made from materials like silicon oxides, titanium oxides, or alumina, placed between the encapsulating assembly and photovoltaic cells to block gas permeation, along with an atomic layer deposition method for precise layer formation, and electrical connections deposited on the barrier layer for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional encapsulation materials (EVA) are used to encapsulate photovoltaic cells, then the cells are protected and encapsulated, but the encapsulant decomposes into corrosive acetic acid over time which degrades the cells
Solution Approach 1:
The patent introduces an aluminum oxide barrier layer as an intermediary between the EVA encapsulant and the photovoltaic cell. This barrier layer mediates the interaction by blocking the diffusion path of acetic acid molecules from the encapsulant to the cell, preventing corrosion while maintaining the encapsulation function. The barrier layer has low acetic acid transmission rate and high chemical stability.
Solution Approach 2:
The patent creates a composite encapsulation structure combining EVA encapsulant with an aluminum oxide barrier layer. This composite system leverages the adhesive and protective properties of EVA while adding the gas barrier properties of aluminum oxide, achieving both encapsulation and corrosion protection functions simultaneously.
2Power
If perovskite or organic semiconductor materials are used to achieve high conversion efficiency, then the photovoltaic module efficiency increases, but the sensitivity to atmospheric gases (water, oxygen) increases leading to faster degradation
Solution Approach 1:
The aluminum oxide barrier layer serves as a protective intermediary between the atmosphere and the sensitive perovskite/organic semiconductor materials. It blocks water vapor and oxygen diffusion to the cell surfaces, preventing degradation reactions while allowing the high-efficiency materials to function.
Solution Approach 2:
The aluminum oxide barrier layer creates a chemically inert environment around the photovoltaic cell by providing a physical barrier that prevents atmospheric gases (water, oxygen) from reaching the cell. This inert barrier protects the sensitive materials from oxidation and hydrolysis reactions.
3Reliability
If a barrier layer with very low water vapor transmission rate is introduced to block gas permeation, then the protection against atmospheric gases improves, but the device complexity increases
Solution Approach 1:
The patent uses a thin film aluminum oxide barrier layer (deposited by atomic layer deposition) to provide gas barrier protection. This thin film approach achieves effective protection without adding significant structural complexity or thickness, maintaining flexibility and simplicity of the overall encapsulation system.
Solution Approach 2:
The patent replaces complex multi-layer mechanical encapsulation structures with a simple atomic layer deposited aluminum oxide barrier. The ALD process creates a conformal, pinhole-free barrier in a single step, simplifying the manufacturing process compared to traditional multi-layer lamination approaches.
4Ease of manufacture
If electrical connections are deposited directly on photovoltaic cells, then the electrical connectivity is established, but leakage current occurs and complex masking steps are required
Solution Approach 1:
The aluminum oxide barrier layer serves as an intermediary substrate for depositing electrical connections. It provides a stable, flat surface that facilitates uniform metal deposition and adhesion. The barrier layer's inertness prevents chemical reactions between the metal contacts and the cell, eliminating leakage current while simplifying the manufacturing process by removing masking steps.
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 barrier layer significantly reduces gas permeation, enhancing the durability and longevity of photovoltaic modules while maintaining optimal electrical and optical properties, and facilitating easier manufacturing by avoiding leakage current and complex contact masking steps.
Implementation Method 1
a barrier layer arranged at an interface between the encapsulating assembly and at least one photovoltaic cell, the barrier layer being configured to at least partially cover the at least one photovoltaic cell, and to have a gaseous Oz transmission rate lower than that of the encapsulating assembly, and a water vapor transmission rate less than or equal to 10^-2
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
Photovoltaic module (100) comprising: - several photovoltaic cells (1a,1b) arranged side by side, and electrically connected to each other, - an encapsulating assembly (2), configured to encapsulate the photovoltaic cells (1a,1b), and - a barrier layer (3) disposed at an interface between the encapsulating assembly (2) and at least one photovoltaic cell (1a,1b), the barrier layer (3) being configured to cover at least part of the at least one photovoltaic cell (1a,1b), and to have a lower gaseous Oz transmission rate than that of the encapsulating assembly (2), and a water vapor transmission rate less than or equal to 10-2g/m2/day measured at 38°C under a humidity level of 85%, so as to form a barrier to the transmission of water vapor and gaseous Oz.