Photovoltaic Panel Recycling via Directional Thermal EVA Separation
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Solution Overview
Problem
Current recycling methods for photovoltaic panels are inefficient in separating glass from silicon, leading to contamination, material loss, and high operational costs, particularly due to the fragmentation of photovoltaic cells and incomplete separation of components like the backsheet, which affects the purity and recovery of silicon and glass.
Innovation Solution
A method and apparatus for recycling photovoltaic panels that involves cutting the rear support plate to facilitate incomplete combustion of the junction insulating plates while maintaining the integrity of the junction plates, allowing for directional heat treatment to separate the glass, silicon, and metal contacts efficiently, using a tunnel furnace with a reverse flame burner and air preheating to optimize combustion and reduce contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical grinding is used to separate glass from the sandwich, then the separation process is simple, but the glass purity is contaminated by remaining EVA and the photovoltaic cells are reduced to small pieces
Solution Approach 1:
The invention changes the thermal parameter by heating the sandwich to a specific temperature range (70-90°C) to soften the EVA junction insulating plates, enabling glass separation without mechanical grinding that would contaminate the glass or fragment the cells
Solution Approach 2:
The invention replaces the mechanical grinding system with a thermal treatment system that uses controlled heating to soften and separate the EVA, thereby avoiding the contamination and fragmentation problems associated with mechanical methods
2Quantity of substance
If chemical reagents are used to dissolve EVA, then the EVA is removed, but the photovoltaic cells break due to swelling and the method is dangerous
Solution Approach 1:
The invention replaces the chemical dissolution method with a thermal treatment method that uses controlled heating to soften and separate the EVA, eliminating the need for dangerous chemical reagents that cause cell swelling and breakage
Solution Approach 2:
The invention changes the separation mechanism from chemical dissolution to thermal softening by controlling the temperature parameter within a specific range, thereby removing EVA without causing the swelling and cell damage associated with chemical methods
3Loss of energy
If complete combustion of polymers is used to valorise materials, then the energy recovery is high, but the operating costs are considerably higher due to energy expenditure
Solution Approach 1:
The invention applies partial combustion by controlling the temperature to soften and separate the EVA without completely combusting all polymer materials, thereby reducing energy expenditure and operating costs while still achieving effective material separation and valorisation
4Loss of energy
If complete combustion of the backsheet is used, then the polymers are fully valorised, but titanium oxide or barium sulphate dust contaminates the glass and silicon
Solution Approach 1:
The invention applies partial combustion by controlling the temperature and exposure time to avoid complete combustion of the backsheet, thereby preventing the formation of contaminating dust while still achieving sufficient polymer valorisation
Solution Approach 2:
The invention applies different treatment intensities to different parts of the sandwich structure, selectively softening the EVA for separation while avoiding conditions that would cause complete backsheet combustion and contamination of the glass and silicon
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 approach enhances the efficiency and quality of material recovery, reduces energy consumption, and lowers operational costs by ensuring complete combustion of insulating plates without damaging silicon cells and minimizing contamination, thus optimizing the recycling process.
Implementation Method 1
generating a directional flow of heat that laps and heats the rear support plate so as to cause the complete combustion of the junction insulating plates
Implementation Method 2
directional flow of heat that laps and heats the rear support plate
Implementation Method 3
subjecting the sandwich to heat treatment in the furnace until the sandwich is broken up into a first set of materials
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
The present invention relates to a method, a plant and an apparatus for recycling photovoltaic panels of the type formed by a frame (20) enclosing a sandwich (200) comprising a glass plate (21) connected to a plurality of photovoltaic cells (23) by means of a first junction insulating plate (22), wherein the photovoltaic cells (23) comprise silicon elements (23a) and metal contacts (23b) wherein, in particular, the method provides for performing a heat treatment such as to result in the complete combustion of the junction insulating plate (24) and the incomplete combustion of the rear support plate (25). The plant comprises at least one treatment apparatus (300) extending between a loading zone (31) and an unloading zone (32) and is configured to perform an initial break-up of the sandwich (200). The plant further comprises at least one separation apparatus (600) configured to perform a separation of glass elements (21') from silicon elements (23a), which is positioned in succession to the treatment apparatus (300). The treatment apparatus (300) comprises a feeding device (30) adapted to transport the sandwich (200) from the loading zone (31) to the unloading zone (32) through a continuously operating tunnel furnace (40), comprising at least one heater device (44) configured so that a directional flow of heat is placed in proximity to an upper surface of the sandwich (200).