Photovoltaic Module Air Gap Design for Thermal Stress
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Solution Overview
Problem
Existing photovoltaic modules face challenges in reducing encapsulation material consumption while maintaining effective heat transfer and protecting against thermo-mechanical stresses, especially in high-temperature solar thermal applications.
Innovation Solution
A photovoltaic module design featuring a solar cell spaced from a support structure by an air gap with locally limited depressions and elastic, cohesive connections made of temperature-resistant materials, allowing for minimal air gaps and compensating for thermal expansion differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solar cells are laminated onto the support structure using encapsulation material, then the solar cells are protected and stabilized, but the material consumption of encapsulation material is high
Solution Approach 1:
The continuous encapsulation material layer is segmented into discrete locally limited depressions on the support structure. This segmentation allows the solar cell to be connected at specific points rather than across the entire surface, dramatically reducing encapsulation material consumption while maintaining protection and stabilization functions at critical connection points.
Solution Approach 2:
The support structure features locally limited depressions that concentrate the encapsulation material and contact material only where needed for connection and protection. This local quality approach ensures that material is applied precisely at connection points rather than uniformly across the entire solar cell surface, reducing overall material consumption while maintaining reliability.
2Loss of substance
If the layer thickness of encapsulation material is reduced, then material consumption decreases, but thermo-mechanical stresses cannot be compensated
Solution Approach 1:
The solution moves from a two-dimensional continuous layer to a three-dimensional locally limited depression structure. The depressions provide vertical depth that allows the contact material to deform and compensate for thermal expansion differences, while the localized nature reduces overall material consumption. This dimensional change enables both reduced material use and stress compensation.
Solution Approach 2:
The invention changes the geometric parameters of the encapsulation material arrangement by creating locally limited depressions with specific depth and surface area characteristics. This parameter change allows the contact material to have sufficient volume for stress compensation while reducing the total surface area covered, thereby reducing overall material consumption.
3Temperature
If solar cells are placed close to the support structure, then heat transfer improves, but thermo-mechanical stresses increase due to thermal expansion differences
Solution Approach 1:
The contact between solar cell and support structure is segmented into discrete locally limited depressions rather than continuous contact. This segmentation allows thermal expansion to occur in the air gap regions while maintaining heat transfer pathways through the depression regions, balancing heat transfer efficiency with stress reduction.
Solution Approach 2:
The air gap acts as an intermediary between the solar cell and support structure, providing mechanical decoupling to reduce stress transmission while still allowing thermal conduction. The locally limited depressions with contact material serve as intermediary zones that facilitate both thermal transfer and stress accommodation.
4Loss of substance
If an air gap is introduced between solar cell and support structure, then material consumption decreases and stress is reduced, but heat transfer efficiency decreases
Solution Approach 1:
The air gap is not uniform but is locally limited to specific depression regions. This local quality approach creates a hybrid structure where air gap regions provide stress relief and material savings, while depression regions with contact material provide enhanced heat transfer pathways, achieving both reduced material consumption and maintained thermal performance.
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
Significantly reduces encapsulation material usage, enhances heat transfer, and improves thermal stress resistance, leading to cost savings and increased efficiency in both electrical and thermal performance.
Implementation Method 1
The problem of linear thermal expansion differences between the solar cell, which can be based on silicon or copper, and the support structure, which can be made of glass, aluminum or copper, must be solved
Implementation Method 2
The increased joint width makes it possible to compensate for thermo-mechanical displacements caused by deformation of the contact material of the bonded connection within the depression
Implementation Method 3
Since solar cells have to dissipate considerable amounts of heat during operation, good heat transfer between the solar cells and the support structure is advantageous
Data Source
Figure 1~4
AI summary
The invention relates to a photovoltaic module consisting of at least one solar cell and a support structure, wherein the solar cell is spaced apart from the support structure by an air gap, and wherein bonds between the solar cell and the support structure only exist rarely at individual points. As a result photovoltaic modules are provided in which the amount of contact material for the bond can be significantly reduced.