Blend Elastomer Conductive Adhesive for Solar Cell Thermal Stress
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Solution Overview
Problem
Solar cell modules face thermal stress and warping due to differences in thermal shrinkage coefficients between semiconductor structures, surface electrodes, and soldering materials, which can lead to cracking, and existing polymer-based electrically conductive adhesives lack sufficient weathering resistance.
Innovation Solution
A solar cell module using an electrically conductive adhesive composition with a polymer matrix comprising a blend of ethylene/alkyl (meth)acrylate copolymer elastomer and ethylene vinyl acetate copolymer, combined with conductive particles, where the weight ratio of the copolymers ranges from 10:90 to 70:30, and the conductive particles are dispersed at 40-90 wt%, providing improved thermal cycling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soldering is used to connect wiring members with surface electrodes, then electrical connection is achieved, but thermal stresses cause warping and cracking due to difference in thermal shrinkage coefficients
Solution Approach 1:
The patent changes the material parameter from traditional solder to polymer-based electrically conductive adhesive, which has different thermal properties that reduce thermal stress during curing and operation, thereby preventing warping and cracking while maintaining electrical connection reliability
Solution Approach 2:
The patent uses composite materials consisting of polymer matrix combined with conductive particles (such as metal粉末) to create an electrically conductive adhesive that provides both mechanical bonding and electrical conductivity, replacing traditional solder while reducing thermal stress effects
2Object-affected harmful factors
If polymer-based electrically conductive adhesives are used instead of solder, then thermal stress is reduced, but weathering resistance is insufficient
Solution Approach 1:
The patent enhances weathering resistance by creating a composite adhesive system where conductive particles are dispersed in a polymer matrix, and the mixture is further blended with elastomers to form a composite material that resists degradation from environmental factors while maintaining electrical conductivity and mechanical properties
Solution Approach 2:
The patent applies local quality enhancement by specifically selecting and combining materials with complementary properties: the polymer matrix provides baseline weathering resistance, while the added elastomers provide additional flexibility and environmental stability in specific regions of the adhesive composition
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 blend elastomer-based adhesive composition significantly enhances the resistance to thermal cycling, reducing solar cell efficiency loss by up to 50% compared to traditional adhesives, maintaining performance after multiple thermal cycles.
Implementation Method 1
the electrically conductive adhesive is formed of an adhesive composition comprising a polymer matrix and 40-90 wt % of conductive particles dispersed in the polymer matrix
Implementation Method 2
the at least one ethylene/alkyl (meth)acrylate copolymer elastomer and/or the at least one ethylene vinyl acetate copolymer is cross-linked with a cross-linking agent
Data Source
AI summary
Disclosed herein is an electrically conductive adhesive composition and its use in solar cell modules, wherein the electrically conductive adhesive comprises a polymer matrix and dispersed in the polymer matrix about 40-90 wt % of conductive particles, with the wt % of all components comprised in the compositions totaling to 100 wt %, and wherein the polymer matrix comprises or is formed of a blend of at least one ethylene/alkyl (meth)acrylate copolymer elastomer and at least one ethylene vinyl acetate copolymer at a weight ratio ranging from about 10:90 to about 70:30.