Solar Cell Module Insulating Sheet Thermal Stress
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Solution Overview
Problem
There is a growing demand for solar modules with improved durability, as existing back contact solar modules face challenges in maintaining structural integrity and preventing delamination due to thermal expansion differences between circuit boards and solar cells.
Innovation Solution
The solar module design includes solar cell strings arranged in one direction with metal foil wiring members that connect adjacent cells, featuring a resin film and metal foil configuration with insulating sheets to prevent stress and delamination, ensuring reliable electrical connections and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If circuit boards are used to connect back contact solar cells, then electrical connection is achieved, but thermal expansion differences cause stress and delamination
Solution Approach 1:
An insulating sheet is introduced as an intermediary component between the circuit board and the solar cell. This insulating sheet has a thermal expansion coefficient that matches that of the solar cell, serving as a mediator that prevents stress and delamination caused by thermal expansion differences between the circuit board and solar cell, while maintaining electrical connection reliability through conductive members.
Solution Approach 2:
The thermal expansion coefficient parameter of the insulating sheet is specifically selected to match that of the solar cell. By changing the material parameter of the insulating sheet to have similar thermal expansion characteristics with the solar cell, the stress caused by thermal expansion differences is minimized, preventing delamination while maintaining structural integrity.
2Strength
If insulating sheets are added between wiring members and solar cells, then stress-induced delamination is minimized, but device complexity increases
Solution Approach 1:
The insulating sheet performs multiple functions simultaneously: it provides electrical insulation between the wiring member and solar cell, mechanically bonds the circuit board to the solar cell, and prevents stress-induced delamination by matching thermal expansion coefficients. This multi-functionality reduces the need for additional separate components, thereby minimizing increased device complexity.
Solution Approach 2:
The insulating sheet combines insulation, bonding, and stress prevention functions into a single integrated component. By merging these functions that could otherwise require separate components, the overall device complexity is minimized while achieving the desired structural integrity and preventing delamination.
3Strength
If metal foil wiring members are used instead of circuit boards, then thermal expansion stress is reduced, but manufacturing precision requirements increase
Solution Approach 1:
Metal foil wiring members are used instead of rigid circuit boards to reduce thermal expansion stress. The thin film structure of the metal foil allows for flexibility and better conformability to the solar cell surface, reducing stress while the insulating sheet provides the necessary structural support and alignment reference for manufacturing precision.
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
This configuration enhances the durability of solar modules by minimizing stress-induced delamination and improving connection reliability, while also reducing the size and cost of insulating sheets, resulting in a more robust and cost-effective solar module.
Implementation Method 1
The insulating sheet is arranged between the first wiring member and the solar cell
Implementation Method 2
The third wiring member has resin film and metal foil arranged on the resin film
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A solar module is provided which has improved durability. A third wiring member (32a) includes a first portion (32a1), a second portion (32a2), and a third portion (32a3). In the first portion (32a1), metal foil (52) faces a solar cell (20). The first portion (32a1) is electrically connected to the solar cell (20). The second portion (32a2) is arranged on the solar cell (20) with the metal foil (52) facing the side opposite to the solar cell (20). The third portion (32a3) connects the first portion (32a1) and the second portion (32a2). A first wiring member (32b) electrically connects the second portions (32a2) of adjacent solar cell strings (10) to each other. The solar module (1) also includes an insulating sheet (60). The insulating sheet (60) is arranged between the first wiring member (32b) and the solar cell (20).