Back-Contact Solar Cell Module Connector Layout for Thermal Stress
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Solution Overview
Problem
Solar cell modules with back contact configurations face issues due to thermal expansion and contraction of metal wires, leading to disconnection of electrodes and reduced adhesive strength between metal wires and intercell connectors, especially under varying environmental temperatures.
Innovation Solution
A solar cell module design featuring conductive lines and intercell connectors with asymmetric patterns and shapes, including slits, holes, protrusions, and zigzag configurations, to reduce shear stress and maintain adhesive strength across temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal wires are connected to back surface electrodes through conductive adhesive layers, then electrical connection is achieved, but thermal expansion and contraction cause disconnection and reduced adhesive strength
Solution Approach 1:
The intercell connector is designed with an asymmetric planar shape featuring a slit that divides the connector into first and second portions with different areas. This asymmetric configuration creates differential thermal expansion behavior between the two portions, allowing the connector to accommodate thermal stress from metal wire expansion and contraction without disconnection or adhesive strength loss.
Solution Approach 2:
The intercell connector is segmented by the slit into multiple portions (first and second portions) with different areas. This segmentation allows each portion to respond differently to thermal expansion forces, with the larger area portion accommodating more expansion and the smaller area portion providing structural stability, thereby preventing connector deformation and disconnection.
2Productivity
If multiple conductive lines are connected to the intercell connector, then electrical connectivity is improved, but shear stress from thermal expansion deforms the connector and causes disconnection
Solution Approach 1:
The asymmetric design with the slit creates portions of different areas that distribute shear stress differently. When multiple conductive lines expand thermally, the asymmetric structure provides varied stress distribution paths, preventing concentrated shear stress that would otherwise deform the connector or cause disconnection while maintaining electrical connectivity.
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 minimizes thermal expansion-induced disconnections and maintains physical adhesive strength between conductive lines and electrodes, enhancing the reliability and efficiency of the solar cell module.
Implementation Method 1
the metal wires may be thermally expanded or thermally contracted, and the metal wires and the electrodes of the solar cell may be disconnected from each other
Data Source
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AI summary
A solar cell module includes a plurality of solar cells each including a semiconductor substrate and first electrodes and second electrodes extended on a back surface of the semiconductor substrate, first conductive lines connected to the first electrodes at crossings between the first electrodes and the first conductive lines through first conductive adhesive layers, second conductive lines connected to the second electrodes at crossings between the second electrodes and the second conductive lines through the first conductive adhesive layers, and an intercell connector extended between a first solar cell and a second solar cell that are adjacent to each other. The first conductive lines connected to the first solar cell and the second conductive lines connected to the second solar cell are commonly connected to the intercell connector.