Photovoltaic Module Encapsulation Film to Prevent Gas Bubbles
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Solution Overview
Problem
Conventional encapsulation methods for photovoltaic modules, such as those using ethylene-vinyl acetate (EVA) and silicone, face issues like acetic acid corrosion, bubble formation leading to pressure issues in space applications, and aesthetic and efficiency problems due to gas bubbles, as well as limited temperature compatibility.
Innovation Solution
A method involving the use of a polymer material crosslinked at least at its gel point for encapsulation, combined with a crosslinkable adhesion layer to form a stable encapsulation envelope, which limits the amount of liquid crosslinkable material and prevents gas bubble formation during manufacturing, ensuring better control over encapsulant thickness and preventing delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If liquid-based encapsulation (silicone) is used, then ease of manufacture is improved, but gas bubbles are formed within the encapsulant
Solution Approach 1:
The patent changes the physical state parameter of the encapsulation material from liquid to solid gel form. The gel form maintains the ease of application and bonding properties of liquid materials while eliminating the formation of gas bubbles, as the gel structure does not trap air during the encapsulation process.
Solution Approach 2:
The patent utilizes the phase transition concept by employing a gel material that can be applied in a soft, moldable state and then cured to a solid state. This phase transition allows the material to fill the encapsulation space uniformly without trapping air bubbles, then locks in the bubble-free structure upon curing.
2Ease of manufacture
If liquid-based encapsulation is used, then ease of manufacture is improved, but control of encapsulant thickness becomes difficult
Solution Approach 1:
The patent changes the viscosity and flow properties of the encapsulation material by using a gel form instead of liquid. The gel maintains sufficient flowability for easy application and bonding while providing enough structural integrity to maintain uniform thickness and prevent runaway flow during the encapsulation process.
3Ease of manufacture
If EVA is used for encapsulation, then ease of manufacture via hot lamination is improved, but acetic acid is generated that corrodes electrodes
Solution Approach 1:
The patent changes the chemical composition parameter of the encapsulation material from EVA polymer to silicone-based gel. This material substitution eliminates the decomposition reaction that produces acetic acid, while maintaining the hot lamination processing capability through the gel's thermal properties and crosslinking behavior.
Solution Approach 2:
The patent addresses the harmful byproduct issue by selecting a gel material whose curing or decomposition products are benign. The silicone-based gel cures to form a stable, non-corrosive encapsulation that protects the electrodes rather than corroding them, converting the potential harm of material decomposition into a protective benefit.
4Ease of manufacture
If EVA is used for encapsulation, then ease of manufacture is improved, but yellowing occurs over time due to ultraviolet radiation
Solution Approach 1:
The patent changes the chemical structure parameter of the encapsulation material from EVA to silicone-based gel. The silicone gel contains silicon-oxygen bonds that are inherently more resistant to UV degradation and do not undergo the same oxidation reactions that cause yellowing in EVA, thereby maintaining optical clarity over extended periods.
5Ease of manufacture
If EVA is used for encapsulation, then ease of manufacture is improved, but temperature compatibility is limited
Solution Approach 1:
The patent changes the thermal properties parameter of the encapsulation material by using silicone-based gel, which has a much wider glass transition temperature range and maintains flexibility and bonding capability across extreme temperatures from -65°C to +200°C, unlike EVA which becomes brittle at low temperatures and degrades at high temperatures.
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
This approach enhances the reliability and efficiency of photovoltaic modules by reducing bubble formation, improving temperature compatibility, and maintaining structural integrity, particularly in space applications, while maintaining transparency and mechanical stability.
Implementation Method 1
an encapsulation film based on a polymer material crosslinked at least at its gel point
Implementation Method 2
an adhesion layer based on a crosslinkable polymer material, the adhesion layer being intended to bond the encapsulation film to the photovoltaic cell
Data Source
AI summary
A method for manufacturing a photovoltaic module having at least one photovoltaic cell includes a step of encapsulating the photovoltaic cell including the formation of a stack having the photovoltaic cell; an encapsulation film based on a polymer material cross-linked at least at its freezing point; and an adhesion layer based on a crosslinkable polymer material. The adhesion layer is configured to adhere the encapsulation film to the photovoltaic cell. The manufacturing method also includes a cross-linking step including cross-linking the crosslinkable polymer material of the adhesion layer.