Embedded Optical Fiber Temperature Sensor for Photovoltaic Laminate

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Solution Overview

Problem

Current methods for measuring temperature within a laminate structure, such as photovoltaic modules, are inadequate as they either provide surface temperature readings or are intrusive, affecting the module's functionality and accuracy, and fail to accurately represent internal temperatures.

Innovation Solution

A sensor device comprising a capillary embedded between layers of the laminate with an optical fiber and a medium, featuring temperature-dependent transmission characteristics, allowing for non-invasive, localized temperature measurements without interfering with the laminate's strain or function, using fiber Bragg gratings for precise temperature detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional thermocouples are mounted on the laminate surface, then temperature measurements can be obtained, but the measurements do not accurately represent internal temperatures and the geometric constraints prevent incorporation within the laminate structure

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidinstallation feasibility
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The optical fiber temperature sensor is embedded within a capillary that is integrated between the layers of the laminate structure during manufacturing. This nested configuration allows the sensor to be positioned internally without disrupting the external geometry or requiring post-manufacturing modifications, thereby achieving both accurate internal temperature measurement and ease of installation.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent replaces conventional electrical thermocouples with optical fiber sensors that use light transmission characteristics to measure temperature. This substitution eliminates the need for electrical wiring and electromagnetic signals, allowing the sensor to be embedded within the laminate structure without interfering with electrical components or requiring complex wiring installations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If thermocouples with wiring are incorporated within the laminate structure, then internal temperature measurements can be obtained, but electromagnetic interference affects the measurements and the wiring complicates the structure

Engineering Contradiction:
Improveinternal temperature measurement accuracyVSAvoidelectromagnetic interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces electrical thermocouples and wiring with optical fiber sensors that transmit temperature information through light rather than electrical signals. This substitution eliminates electromagnetic interference entirely, as optical fibers are immune to electromagnetic fields, while maintaining the capability to measure internal temperatures accurately.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The optical fiber acts as an intermediary that transfers temperature information from the internal sensor location to external measurement equipment without requiring electrical connections within the laminate. The light transmission through the optical fiber provides a clean signal path that is not susceptible to electromagnetic interference from surrounding electrical components.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If fiber Bragg grating sensors in steel tubes are used, then surface temperature measurements can be obtained, but the sensors do not provide accurate temperature information regarding the inside of the laminate structure

Engineering Contradiction:
Improvesurface temperature measurement accuracyVSAvoidinternal temperature information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The optical fiber sensor is nested within a capillary that is embedded between the layers of the laminate structure during manufacturing. This internal positioning allows the sensor to directly measure temperatures at the location of interest within the laminate, providing accurate internal temperature information that surface-mounted sensors cannot capture.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent positions the temperature sensor at specific locations within the laminate structure where temperature measurement is most critical, such as near photovoltaic cells or other heat-generating components. This localized sensing approach provides targeted temperature information that is relevant to the functional performance of the laminate, rather than generic surface temperatures.

Inventive Principle:
Principle #3Local quality

4Measurement precision

If multiple materials are introduced into the laminate structure for sensing, then temperature measurements can be obtained, but the additional materials influence the measurement results and the function of the PV module

Engineering Contradiction:
Improvetemperature measurement capabilityVSAvoidmodule function integrity
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent uses optical fiber sensors that rely on light transmission properties rather than electrical or thermal contact with laminate materials. This measurement approach minimizes interaction with surrounding materials, as the optical fiber can be surrounded by a matching medium that does not conduct heat or electricity, thereby avoiding interference with the electrical function of photovoltaic cells and other sensitive components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a matching medium (such as epoxy or silicone) that surrounds the optical fiber within the capillary. This intermediary material provides mechanical support and thermal coupling for accurate temperature measurement while being electrically insulating and optically transparent, thus not interfering with the electrical function of photovoltaic cells or the optical transmission through the fiber.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables accurate, non-invasive temperature measurements within the laminate structure with high spatial resolution and minimal impact on the surrounding structure, decoupling thermal and mechanical measurements for reliable data collection.

Implementation Method 1

at least a portion of the optical fiber has temperature-dependent transmission characteristics

Methodology Applied
Scientific EffectTemperature-dependent transmission characteristics: Refraction

Implementation Method 2

the strain sensor is another optical fiber with strain-dependent transmission characteristics

Methodology Applied
Scientific EffectStrain-dependent transmission characteristics: Photoelasticity

Implementation Method 3

A change in temperature will cause the glass fibers with the fiber Bragg grating sensors to expand, wherein the temperature change may be optically detected

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3913798B1Thermal monitoring in laminate structures
Publication Date: 2023.06.28 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)
  • EP3913798B1 patent drawingFigure 1a~1b
  • EP3913798B1 patent drawingFigure 2a~2c
  • EP3913798B1 patent drawingFigure 3~4

AI summary

A sensor device (10) for measuring a temperature in a photovoltaic laminate structure (20) and a sensor system (30) comprising such a sensor device (10) is provided. The sensor device (10) comprises: a capillary (12) for being embedded in the laminate structure (20) between two layers (22) thereof; a medium (14) arranged within the capillary (12); and an optical fiber (16) extending through the capillary (12) and surrounded by the medium (14), wherein at least a portion (17) of the optical fiber (16) has temperature-dependent transmission characteristics.