Solar Battery Module Encapsulant Temperature Differential
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Solution Overview
Problem
Existing solar cell module production methods face challenges in achieving a good appearance due to the projection phenomenon caused by thermal shrinkage of back sheets, leading to deformation of lead wires and misalignment of solar cell devices, and the high cost associated with thermal fixation steps to mitigate these issues.
Innovation Solution
Specifying a combination of encapsulants for the upper and back sheets with a specific flow beginning temperature relationship (TB−TD > 0°C) to prevent the projection phenomenon, where the encapsulant on the upper protective material has a higher flow beginning temperature than the back sheet encapsulant, ensuring efficient lamination conditions and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a back sheet with low thermal shrinkage rate is used to prevent projection phenomenon, then the appearance quality is improved, but the production cost increases due to thermal fixation steps
Solution Approach 1:
The invention changes the thermal parameters of the back sheet by selecting materials with specific glass transition temperatures and thermal shrinkage characteristics. The back sheet is designed to have a glass transition temperature of -50°C to 0°C and thermal shrinkage rate of 3% or less at 150°C, eliminating the need for additional thermal fixation steps while maintaining appearance quality.
Solution Approach 2:
The back sheet is constructed as a composite material consisting of a polyester resin base layer and a fluororesin coating layer. This composite structure provides both the required thermal stability (low shrinkage) and the necessary weather resistance, while avoiding the need for expensive thermal fixation processes.
2Reliability
If trial-and-error method is used to set lamination conditions, then various member compatibility is achieved, but the time consumption and member cost increase
Solution Approach 1:
The invention performs preliminary selection of back sheet materials with specific thermal properties (glass transition temperature of -50°C to 0°C and thermal shrinkage rate of 3% or less at 150°C) before the lamination process. This preliminary material selection establishes predictable lamination conditions without requiring extensive trial-and-error testing, reducing both time and cost.
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 solution allows for the production of solar cell modules with a good appearance and reduced production time and costs by predicting the final appearance based on encapsulant flow beginning temperatures, preventing deformation and misalignment, and optimizing lamination conditions.
Implementation Method 1
the back sheet may shrink and the solar cell device and the lead wire (tag) that connects the devices may follow the back sheet shrinkage
Implementation Method 2
the flow beginning temperature (TB) (° C.) of the encapsulant (B) and the flow beginning temperature (TD) (° C.) of the encapsulant (D), as measured under a load of 1 kgf/cm2, have the following relationship: TB−TD＞0 (° C.)
Data Source
AI summary
A solar cell module having a good appearance after lamination and a method for producing such a solar cell module are provided by specifying the combination guideline for encapsulants capable of bettering the appearance after lamination. The solar cell module contains an upper protective material (A), an encapsulant (B) for use on the side of the upper protective material (A), a solar cell device (C), an encapsulant (D) for use on the side of a back sheet (E), and the back sheet (E), wherein the encapsulant (B) and the encapsulant (D) satisfy the following requirement (P), and the production method produces the solar cell module. Requirement (P): The flow beginning temperature (TB) (° C.) of the encapsulant (B) and the flow beginning temperature (TD) (° C.) of the encapsulant (D), as measured under a load of 1 kgf/cm2, have the following relationship: TB−TD>0 (° C.).