Methods and apparatus for detecting cross-linking in a polymer
Inventors
Doble, Dan • Mickiewicz, Rafal • Lloyd, John • Jaeger, Marco • Hartman, William F.
Assignees
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Publication Number
US-8950267-B2
Publication Date
2015-02-10
Expiration Date
Abstract
Methods and apparatus for detecting cross-linking in a polymer, wherein, in some exemplary implementations, the polymer may constitute an encapsulation layer for a photovoltaic module. In one example, a polymer sample is physically deformed, and sample information relating to a relaxation or a recovery of the polymer sample in response to the deformation is obtained. The sample information is then compared to reference information relating to cross-linking of the polymeric material so as to determine a degree of cross-linking in the tested polymer sample. In one aspect, such a determination of polymer cross-linking is achieved without adversely affecting a relevant functionality of the polymer/encapsulation layer (e.g., without destruction to the polymer/encapsulation layer).
Core Innovation
The invention detects cross-linking in a polymer sample by physically deforming the polymer sample using a tester, and obtaining sample information relating to relaxation or recovery of the polymer sample in response to the physical deformation. The sample information is then compared to reference information relating to the cross-linking to determine a degree of the cross-linking in the polymer sample.
The disclosed approach emphasizes obtaining information from a relaxation or recovery process after deformation so that physical response information is used for determining cross-linking degree without relying on destructive cross-linking measurement. The disclosure contrasts with conventional destructive gel fraction, creep, and DSC methods, and uses deformation, relaxation, or deformation, recovery response as the basis for comparison to reference cross-linking information.
The disclosed system and methods are further directed to polymer encapsulant film used in photovoltaic modules, including EVA encapsulant or EVA copolymer film. The deformation and measurement are tied to relaxation time constant, force decay, and related physical response information, enabling determination of cross-linking degree by comparison to reference cross-linking information, with non-destructive performance emphasized.
Claims Coverage
The partial content provides three independent claims that cover method and apparatus aspects of detecting cross-linking degree by physically deforming a polymer, measuring relaxation or recovery physical response, and comparing to reference cross-linking information. Across the independent claims, the core inventive theme is deformation-driven relaxation or recovery measurement followed by comparison to reference information to determine a degree of cross-linking.
Deforming polymer and measuring relaxation or recovery to determine cross-linking degree
A method for detecting cross-linking in a polymer sample comprising physically deforming a polymer sample using a tester; obtaining sample information relating to a relaxation or a recovery of the polymer sample in response to the deforming; and comparing the sample information to reference information relating to the cross-linking so as to determine a degree of the cross-linking in the polymer sample.
Tester with deformation component and processor to compare physical response to reference information
An apparatus for detecting cross-linking in a polymer sample comprising a tester having at least a first component to physically deform the polymer sample and a second component to obtain sample information regarding a physical response of the polymer sample to deformation; and a processor programmed to determine a degree of the cross-linking in the polymer sample at least in part by comparing the sample information to reference information relating to the cross-linking.
Deforming EVA copolymer film and comparing relaxation or recovery information to reference cross-linking information
A method for detecting cross-linking in an ethylene vinyl acetate copolymer film comprising physically deforming the film using a tester; obtaining sample information relating to a relaxation or a recovery of the film in response to the deforming; and comparing the sample information to reference information relating to the cross-linking so as to determine a degree of the cross-linking in the film.
Across the independent claims, cross-linking degree is determined by deforming a polymer, including EVA encapsulant or EVA film, measuring relaxation or recovery physical response information obtained in response to the deformation, and comparing that measured sample information to reference information relating to the cross-linking.
Stated Advantages
Supports in-line or in-laminator testing for faster throughput.
Provides non-destructive detection while avoiding adverse impact on polymer or encapsulation functionality.
Avoids destructive conventional gel fraction, creep, and DSC methods by using relaxation or recovery response for determining cross-linking degree.
Documented Applications
Non-destructive detection of cross-linking in photovoltaic module polymer encapsulant film, including EVA encapsulant, with emphasis on in-laminator or in-line testing.
Mini-module indentation verification using electroluminescence to show no observed cell breakage under typical indentation loads.
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