Ethylene Vinyl Acetate Encapsulant for Continuous PV Module Fabrication
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Solution Overview
Problem
The existing process for fabricating photovoltaic modules is lengthy, expensive, and requires multiple steps, with a batch process for the final heat treatment, lacking a continuous fabrication method.
Innovation Solution
A polymeric composition comprising an ethylene monomer and a carboxylic acid vinyl ester comonomer, with a Brookfield viscosity of 10,000 to 25,000 mPa·s, is used as an encapsulant, allowing direct application and continuous processing of photovoltaic modules by forming a stack with protective sheets and applying a crosslinking treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymeric composition is used as encapsulant film, then good adhesion and mechanical properties are achieved, but the fabrication process becomes lengthy and expensive requiring multiple steps
Solution Approach 1:
The patent combines multiple separate fabrication steps (copolymerization, mixing with additives, film forming, and pressing with heat treatment) into a single integrated process. The polymeric composition is prepared with all necessary components (copolymer, crosslinking agent, silane, anti-UV agents) already mixed together, eliminating the need for separate mixing and film forming steps, thus reducing the number of operations while maintaining product quality
Solution Approach 2:
The polymeric composition serves multiple functions simultaneously: it acts as the encapsulant matrix, contains crosslinking agents for bonding, includes silanes for adhesion improvement, and incorporates anti-UV agents for weather resistance. This multi-functional formulation eliminates the need for separate layers or additional treatment steps, streamlining the fabrication process
2Reliability
If conventional batch process heat treatment is used, then proper crosslinking and bonding are achieved, but continuous fabrication is not possible
Solution Approach 1:
The patent enables continuous fabrication by replacing the batch process heat treatment with a continuous extrusion process. The polymeric composition is extruded directly onto the photovoltaic cells in a continuous manner, and the crosslinking occurs during the extrusion process itself rather than in separate batch cycles. This allows for uninterrupted production while maintaining proper crosslinking and bonding through the extrusion parameters
3Manufacturing precision
If multiple fabrication steps are used, then satisfactory module properties are obtained, but the complete preparation process is lengthy and expensive
Solution Approach 1:
The patent performs preliminary mixing of all necessary components (copolymer, crosslinking agent, silane, anti-UV agents) into a single polymeric composition before the extrusion step. This preliminary preparation ensures that all required functionalities are present in the material itself, eliminating the need for subsequent separate treatment steps and reducing overall process time while maintaining module quality
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 reduces the number of steps, enables continuous fabrication, and maintains the adhesion and mechanical properties of conventional encapsulant films, ensuring reliable and efficient module production.
Implementation Method 1
When the temperature reaches the activation temperature of the crosslinking agent (typically around 150° C.), the polymeric composition crosslinks, thereby making it possible to obtain a very strongly and irreversibly bonded, compact assembly.
Implementation Method 2
When the temperature reaches the melting point of the polymeric composition, the latter flows all around the assembly of photovoltaic cells.
Data Source
AI summary
The use of a polymeric composition as an encapsulant in a photovoltaic module, said polymeric composition including a copolymer that comprises an ethylene monomer and a carboxylic acid vinyl ester comonomer, in particular an ethylene vinyl acetate copolymer, and the polymeric composition having a Brookfield viscosity measured at 120° C. of between 10,000 mPa·s and 25,000 mPa·s. Further, a method for encapsulating a photovoltaic module using this polymeric composition.