Solar Cell Glass Substrate Composition for UV Stability

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Solution Overview

Problem

Solar cells face issues with solarization of glass substrates due to ultraviolet radiation, leading to reduced sunlight intensity and photoelectric conversion efficiency, and existing methods to suppress solarization compromise heat resistance and devitrification-proof properties.

Innovation Solution

A glass substrate composition with specific ratios of SiO2, Al2O3, B2O3, SnO2, and Fe2O3, along with other oxides, is developed to maintain high heat resistance and prevent devitrification while minimizing solarization, with a SnO2/(SnO2+Fe2O3) mass ratio of 0.96 or more and high transmittance, ensuring photoelectric conversion efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a large amount of TiO2 is added to suppress solarization, then solarization is suppressed, but devitrification-proof deteriorates and the glass is colored

Engineering Contradiction:
Improvesolarization suppressionVSAvoiddevitrification-proof
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical composition parameters by replacing TiO2 with SnO2 as the solarization suppression agent. The specific parameter change is setting SnO2 content to 0.01-2 mass% and controlling the SnO2/(SnO2+Fe2O3) mass ratio to 0.94 or more, which achieves solarization suppression without compromising devitrification-proof properties or causing discoloration

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces SnO2 as an intermediary substance that mediates between the conflicting requirements of solarization suppression and maintaining glass stability. SnO2 acts as a more effective and cleaner alternative to TiO2, providing the desired UV protection while maintaining optical clarity and structural stability

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If high heat resistance is required for thin-film compound solar cells, then heat resistance is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveheat resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent achieves high heat resistance by optimizing the glass composition parameters, specifically setting SiO2 at 55-65 mass%, Al2O3 at 5-20 mass%, and B2O3 at 5-20 mass%. This compositional parameter optimization provides inherent heat resistance (strain point ≥500°C) without requiring complex manufacturing processes or additional components

Inventive Principle:
Principle #35Parameter changes

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 substrate effectively suppresses solarization, maintains high transmittance, and provides excellent heat resistance, ensuring sustained photoelectric conversion efficiency and compatibility with solar cell structures.

Implementation Method 1

light is delivered to the cell or the photoelectric conversion layer via the glass substrate

Methodology Applied
Scientific EffectLight transmission: Light

Implementation Method 2

discoloration (hereinafter referred to as solarization) occurs in a glass substrate by ultraviolet ray, which lowers the intensity of sunlight irradiating a solar cell device

Methodology Applied
Scientific EffectSolarization: Absorption (EM radiation)

Implementation Method 3

A solar cell is a device which uses photovoltaic effect and directly converts light energy into electric power

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentEP2119681B1Glass substrate for solar battery
Publication Date: 2015.01.07 NIPPON ELECTRIC GLASS CO LTD

AI summary

The glass substrate for a solar cell of the present invention is characterized by having a glass composition including, in terms of mass%, 50 to 80% of SiO2, 5 to 20% of Al2O3, 5 to 20% of B2O3, 0 to 20% of MgO, 0 to 20% of CaO, 0 to 20% of SrO, 0 to 20% of BaO, 0.001 to 2% of SnO2, 0 to 1% of As2O3, having a mass ratio SnO2/(Fe2O3+SnO2) of 0.9 or more, and having a difference between transmittances at a wavelength of 400 nmbefore and after irradiation with ultraviolet ray of 2% or less.