PV Encapsulation Composition for Thin-Module PID Resistance
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Solution Overview
Problem
Photovoltaic modules face significant challenges in maintaining long-term maximum power output due to Potential Induced Degradation (PID), which causes power output capacity to degrade over time, despite existing attempts to enhance PID resistance in the prior art.
Innovation Solution
A photovoltaic module design incorporating a polymer composition for the encapsulation layer, comprising 97.00 to 99.99 wt.% of ethylene-vinylacetate copolymer, polyolefin elastomer, or ethylene copolymer with silane group-containing units, and 0.01 to 3.00 wt.% of a compound with specific silane groups, along with optional additives, to create a robust encapsulation layer that retains maximum power output over 96 hours under PID stress conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the encapsulation layer is reduced to below 0.5 mm to enable thin photovoltaic modules, then manufacturing cost and material usage are reduced, but resistance to potential induced degradation (PID) decreases
Solution Approach 1:
The patent modifies the chemical composition parameters of the encapsulation layer by incorporating specific compounds (Formula I and Formula II) with silane groups and polar comonomer units. These compositional changes enable the layer to maintain PID resistance at reduced thicknesses of 0.3-0.5 mm, resolving the contradiction between thinness and reliability
Solution Approach 2:
The patent creates a composite encapsulation material by blending base polymers (EVA, POE, or polyethylene) with specific functional compounds (Formula I and Formula II). This composite approach combines the beneficial properties of thin-layer design with enhanced PID protection, achieving both reduced quantity and improved reliability
2Reliability
If existing PID-resistant materials are used in the encapsulation layer, then some PID protection is achieved, but long-term maximum power output retention remains insufficient after 96 hours
Solution Approach 1:
The patent optimizes concentration parameters of active compounds (Formula I and Formula II) within specific ranges to achieve both immediate PID resistance and sustained long-term power retention. The controlled dosing ensures durability extends beyond 96 hours while maintaining high power output
Solution Approach 2:
The patent ensures continuous protective action by incorporating compounds that provide ongoing PID resistance throughout the module's operational life. The encapsulation layer maintains its protective function continuously, preventing power degradation over extended periods rather than providing temporary relief
3Reliability
If thicker encapsulation layers (0.6-2.0 mm) are used to increase PID resistance, then reliability against PID improves, but manufacturing cost and material usage increase
Solution Approach 1:
The patent changes the material composition parameters to achieve superior PID resistance per unit thickness. By incorporating specific compounds (Formula I and Formula II), the encapsulation layer provides enhanced protection at 0.3-0.5 mm thickness, equivalent to or better than conventional 0.6-2.0 mm layers, thus reducing material usage while maintaining reliability
Solution Approach 2:
The patent applies local quality enhancement by concentrating PID-resistant functional compounds specifically within the encapsulation layer where they are most needed. This targeted approach provides maximum protection at minimum thickness, avoiding the need for uniformly thick layers throughout
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 proposed solution effectively enhances PID resistance, allowing photovoltaic modules to maintain a high percentage of their initial maximum power output after 96 hours of PID stress testing, as per IEC 60904 standards, with improved durability and performance.
Implementation Method 1
PID, as the name implies, can occur when the module's voltage potential and leakage current drive ion mobility within the module between the semiconductor material and other elements of the module
Implementation Method 2
the module's voltage potential and leakage current drive ion mobility within the module
Data Source
Figure 1~2
Figure 3
AI summary
The present invention relates a photovoltaic module comprising a protective front layer element, an encapsulation layer element, a photovoltaic cell element and a protective back layer element, whereby at least one of the protective elements comprises glass; wherein the encapsulation layer element comprises a polymer composition (I) comprising at least the following components: (A) 97.00 to 99.99 wt.-% based on the overall weight of the polymer composition (I) of a polymer selected from an ethylenevinylacetate copolymer, a polyolefin elastomer or a polymer of ethylene (a) selected from (a1) a copolymer of ethylene which bears functional groups containing units; (a2) a copolymer of ethylene comprising one or more polar comonomer unit(s) selected from (C1-C6)-alkyl acrylate or (C1-C6)-alkyl (C1-C6)-alkyl acrylate comonomer units, and optionally bears functional groups containing units different from said polar comonomer unit(s); (a3) a copolymer of ethylene comprising one or more alpha-olefin comonomer unit(s); and optionally bears functional groups containing units different from said polar comonomer unit(s) of polymer (a2); or mixtures thereof; and (b) silane group(s) containing units; (B) 0.01 to 3.00 wt.-% based on the overall weight of the polymer composition (I) of a compound according to Formula (I); wherein; R1, R1', R2 and R2' are each independently selected from the group consisting of hydrogen, n-alkyl, iso-alkyl, alkoxy, cycloalkyl, alkenyl, halogen and mixtures thereof; X is selected from the group consisting of primary amines, secondary amines, tertiary amines, hydrogen, alkyl, alkenyl and mixtures thereof; whereby components (A) and (B) add up to 100 wt.-%. Furthermore, the present invention refers to the use of an encapsulation layer element comprising polymer composition (I) according to the invention for increasing the Pmax determined after 96 h according to IEC 60904, by applying the foil method with a temperature of 85°C and relative humidity of 60 % and a potential difference of 1500 V, of a photovoltaic module comprising besides the encapsulation layer element a protective front layer element, a photovoltaic cell element and a protective back element, whereby at least one of the protective elements comprises glass.