Soda Lime Glass Substrate for CIGS Thin Film PV Modules
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Soda lime glass substrates used in thin film photovoltaic modules face challenges with sodium release, leading to delamination issues and reduced efficiency due to uncontrolled sodium delivery and environmental conditions, necessitating a glass composition that provides optimal substrate properties for thin film PV devices.
Innovation Solution
A glass composition comprising SiO2, Al2O3, and Na2O with controlled sodium release rates, a high coefficient of thermal expansion, and a strain point greater than 565°C, designed to maintain manufacturability and compatibility with fusion forming processes, while minimizing sodium and potassium release to prevent delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If soda lime glass is used as substrate, then low cost and sodium content are achieved, but uncontrolled sodium release and delamination issues occur
Solution Approach 1:
The patent modifies the glass composition parameters by replacing part of the sodium oxide with potassium oxide and adjusting the ratio of alkaline earth metals (MgO, CaO, SrO). This changes the sodium release characteristics while maintaining the necessary sodium content for CIGS film formation, thereby resolving the contradiction between having sufficient sodium and preventing uncontrolled release that causes delamination.
Solution Approach 2:
The patent creates a composite glass substrate with a specific multi-component composition including SiO2, Al2O3, B2O3, Na2O, K2O, and alkaline earth metal oxides. This composite formulation balances sodium release properties, thermal expansion characteristics, and chemical stability to prevent delamination while maintaining manufacturability.
2Manufacturing precision
If high sodium release is achieved, then CIGS thin film formation is improved, but delamination and efficiency reduction occur
Solution Approach 1:
The patent applies partial action by providing a controlled, moderate sodium release rather than excessive release. The glass composition is designed to release sodium at a controlled rate during the vacuum evaporation process, sufficient for proper CIGS film formation but limited enough to prevent delamination and efficiency loss.
3Reliability
If glass composition is optimized for sodium control, then delamination is reduced, but manufacturability and processing compatibility may be affected
Solution Approach 1:
The patent adjusts multiple glass composition parameters simultaneously - the ratio of Na2O to K2O, the content of alkaline earth metals, and the overall oxide composition - to achieve a balance where sodium release is controlled but the glass remains compatible with existing fusion forming processes and vacuum evaporation equipment used in PV module manufacturing.
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 glass composition ensures stable sodium release for improved CIGS thin film adhesion, maintains high temperature processing capabilities, and reduces delamination risks, enhancing the efficiency and longevity of photovoltaic modules.
Implementation Method 1
the glass has a sodium release greater than 10 ppm in a buffered aqueous release test and a total sodium plus potassium release of less than 50 ppm in a buffered aqueous release test
Implementation Method 2
the glass has a coefficient of thermal expansion greater than 6 ppm/° C.
Implementation Method 3
the glass has a strain point greater than 565° C.
Data Source
AI summary
Fusion-formable sodium-containing aluminosilicate and boroaluminosilicate glasses are described. The glasses are particularly useful for controlled release of sodium—useful in semiconductor applications, such as thin film photovoltaics where the sodium required to optimize cell efficiency is to be derived from the substrate glass.