Photovoltaic Panel Recycling via Inclined Slit Separation

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Solution Overview

Problem

Current recycling methods for photovoltaic panels face inefficiencies in separating glass from silicon, leading to contamination, material loss, and increased operational costs, particularly due to mechanical and chemical treatment methods that either fragment cells or require high energy expenditure.

Innovation Solution

A method and apparatus involving a heat treatment to break down the panel into glass, silicon, and metal contacts, followed by a mechanical separation using a comb-like device and an inclined planar element with conveyor elements to efficiently separate silicon from glass, optimizing material recovery and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If mechanical grinding methods are used to separate glass from photovoltaic cells, then the separation process is simple and fast, but the glass purity is contaminated with adherent EVA and the photovoltaic cells are broken into small pieces

Engineering Contradiction:
Improveseparation speedVSAvoidglass purity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by first removing the frame and electrical components to separate the sandwich structure into distinct layers (glass, EVA, cells, backsheet), then using controlled breaking to segment the sandwich into manageable pieces that can be further processed. This preliminary segmentation prevents complete fragmentation while enabling effective separation of glass from other materials.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the glass from the sandwich structure through a combination of mechanical breaking and separation techniques. The glass is extracted as larger fragments rather than being ground into fine particles, maintaining its integrity and purity by preventing contamination from EVA and other materials that would occur in complete grinding processes.

Inventive Principle:
Principle #2Taking out (Extraction)

2Manufacturing precision

If chemical methods are used to dissolve EVA, then the glass can be separated, but the photovoltaic cells are broken due to panel deformation and the process uses dangerous reagents

Engineering Contradiction:
Improveglass separationVSAvoidcell integrity
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces chemical dissolution methods with a mechanical-thermal approach. Instead of using chemical reagents to dissolve EVA, the process uses controlled thermal treatment to soften the EVA, followed by mechanical breaking and separation. This substitution preserves cell integrity while achieving effective glass separation, eliminating the need for dangerous chemical solvents.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical parameters of the EVA by applying thermal energy to soften it, making it more pliable and easier to separate from the glass. This parameter change (temperature increase) allows for mechanical separation without chemical dissolution, preventing cell breakage while achieving effective glass recovery.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If thermal treatment is used to combust the polymer, then the photovoltaic cells are recovered without fragmentation, but the operating costs are considerably higher due to energy expenditure

Engineering Contradiction:
Improvecell recovery qualityVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies partial thermal action by selectively softening only the EVA layers through controlled heating, rather than completely combusting all polymer materials. This partial application of thermal energy achieves the necessary separation while significantly reducing energy consumption compared to full combustion processes, and prevents excessive energy expenditure while maintaining cell integrity.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent extracts only the necessary thermal energy required to soften the EVA for separation, rather than applying excessive heat for complete combustion. This targeted extraction of thermal energy reduces operating costs while achieving effective glass and cell separation, avoiding the high energy expenditure associated with complete polymer combustion.

Inventive Principle:
Principle #2Taking out (Extraction)

4Object-affected harmful factors

If the backsheet is removed before heat treatment, then the silicon cells are less damaged, but the separation becomes more complex and time-consuming

Engineering Contradiction:
Improvecell damageVSAvoidseparation process complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent performs preliminary removal of the frame and electrical components before the main separation process. This preliminary action simplifies the subsequent thermal and mechanical processing by eliminating materials that would interfere with heat distribution and separation, reducing cell damage while avoiding excessive process complexity.

Inventive Principle:
Principle #10Preliminary action

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 enables reliable and cost-effective separation of glass and silicon, improving the quality and quantity of recycled materials while minimizing energy consumption and operational costs.

Implementation Method 1

subjecting the sandwich to heat treatment in a furnace until the sandwich is broken up into a first set of materials comprising glass elements, silicon elements and metal contacts

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Implementation Method 2

sliding the second set of materials along an inclined planar element having at least one pair of side guides and one or more conveyor elements which are arranged along an upper surface of the planar element so as to form one or more slits configured to separate the silicon elements from the glass elements

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3989296B1Method, plant and apparatus for recycling photovoltaic panels
Publication Date: 2022.09.07 9 TECH SRL
  • EP3989296B1 patent drawingFigure 1
  • EP3989296B1 patent drawingFigure 2
  • EP3989296B1 patent drawingFigure 3a~3c

AI summary

The present invention relates to a method, plant and apparatus for recycling photovoltaic panels of the type 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 comprise silicon elements (23a) and metal contacts (23b), wherein, in particular, the plant comprises at least one treatment apparatus (300) extending between a loading zone (31) and a unloading zone (32) and is configured to perform an initial break-up of the sandwich (200) and at least one separation apparatus (600) extending between its own inlet section (61) and its own outlet section (69) and is configured to perform a separation of glass elements (21') from silicon elements (23a). The separation apparatus (600) further comprises an inclinable planar element (60) having at least one pair of side guides (64) and one or more conveyor elements (63, 63', 63") which are arranged along an upper surface (60a) of the planar element (60) so as to form one or more slits (65) configured to separate the silicon elements (23a) from the glass elements (21').