Solar Cell Resin Layer Gradient for Thermal Deformation Control
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Solution Overview
Problem
Conventional solar cells in sheet form deform convexly with temperature increases due to differences in thermal expansion coefficients between the substrate and protective resin layers, leading to performance and aesthetic issues in electronic devices, especially in downsized devices where space is limited.
Innovation Solution
A solar cell design with a first cured resin layer having a linear expansion coefficient not less than the second cured resin layer, and the second cured resin layer having a larger expansion coefficient than the substrate, where the first cured resin layer is formed with an ultraviolet curable epoxy resin and is thicker than the second cured resin layer, to maintain a concave shape even under temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a substrate with small linear expansion coefficient is used to suppress dimensional changes, then thermal stability is improved, but the solar cell deforms convexly when heated due to mismatch with the protective resin layer
Solution Approach 1:
The patent applies local quality by creating a gradient in the linear expansion coefficient within the protective resin layer. The layer has a first region with a smaller linear expansion coefficient (closer to the substrate) and a second region with a larger linear expansion coefficient (closer to the outer surface), allowing different parts of the same layer to serve different functional purposes in managing thermal stress
Solution Approach 2:
The protective resin layer is constructed as a composite material with regions having different linear expansion coefficients. This composite structure enables the layer to simultaneously match the substrate's thermal properties in one region while maintaining its own protective function in another region, resolving the expansion mismatch problem
2Volume of moving object
If the spacing between solar cell and dial plate is reduced for device downsizing, then device compactness is improved, but the light receiving surface contacts the dial plate when heated
Solution Approach 1:
The protective resin layer has spatially varying properties with a gradient in linear expansion coefficient, creating local regions optimized for different functions. This allows the solar cell to maintain proper surface geometry even in compact devices where thermal expansion management is critical
Solution Approach 2:
The patent changes the physical parameter of linear expansion coefficient across the protective resin layer, creating a continuous or stepped gradient from the substrate interface to the outer surface. This parameter variation allows the structure to accommodate thermal expansion without convex deformation, enabling safer spacing in compact devices
3Stability of the object's composition
If a symmetric structure with identical cured resin layers is used to suppress deformation, then structural symmetry is improved, but the solar cell becomes convex at room temperature due to curing shrinkage
Solution Approach 1:
The patent deliberately introduces asymmetry in the protective resin layer by creating regions with different linear expansion coefficients. This asymmetric design within the protective layer counterbalances the symmetric curing shrinkage effects, preventing convex deformation while maintaining overall structural integrity
Solution Approach 2:
The linear expansion coefficient parameter is varied within the protective resin layer to create a gradient structure. This parameter change compensates for the uniform curing shrinkage that occurs in symmetric structures, allowing the solar cell to maintain proper surface geometry at room temperature
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 design effectively suppresses convex deformation of the solar cell with temperature increases, maintaining a stable concave shape and preventing contact with unintended surfaces in electronic devices, thus ensuring performance and appearance are not compromised.
Implementation Method 1
the first cured resin layer is formed of an ultraviolet curable epoxy resin
Data Source
AI summary
In a solar cell in a sheet form, a first cured resin layer, a substrate containing a resin, a photoelectric conversion layer, and a second cured resin layer are stacked in this order. The linear expansion coefficient of the first cured resin layer is not less than that of the second cured resin layer, and the linear expansion coefficient of the second cured resin layer is larger than that of the substrate. When the cure degree of a first surface of the first cured resin layer facing the substrate is C1 % and the cure degree of a second surface of the first cured resin layer is C2 %, C2 is larger than C1 and (C2−C1) is 2 to 15%. A surface on the first cured resin layer of the solar cell is warped convexly and a surface on the second cured resin layer is warped concavely.