Cryogenic Delamination of Photovoltaic Modules

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Solution Overview

Problem

Existing recycling processes for photovoltaic modules are energy-intensive and result in mechanical or chemical deterioration, leading to costly and environmentally harmful fragments that require additional processing for reintegration, failing to effectively recover high-value components and maintaining the structural integrity of materials.

Innovation Solution

A thermo-mechanical controlled cryogenic delamination process that exploits the thermal expansion characteristics and mechanical properties of materials to separate layers without altering their geometrical structure or mechanical properties, using cryogenic cooling, controlled thermal cycles, and mechanical vibrations to achieve delamination, followed by liquid insufflation for final separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If high temperature baking process (480-540°C) is used to separate photovoltaic module layers, then polymeric layers are melted and separated, but energy consumption increases and mechanical/chemical deterioration occurs

Engineering Contradiction:
Improvelayer separationVSAvoidenergy consumption
Core Design Contradiction:
Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The invention changes the temperature parameter from high (480-540°C) to low (cryogenic temperatures), fundamentally altering the separation mechanism from thermal melting to thermal stress-induced delamination. This parameter change reduces energy consumption while achieving effective layer separation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention utilizes phase transitions of the polymeric layers at cryogenic temperatures, where rapid cooling and heating cycles induce thermal stress that causes delamination. The polymeric layers transition between frozen and flexible states, enabling separation without high-temperature melting.

Inventive Principle:
Principle #36Phase transitions

2Loss of substance

If mechanical crushing and acid dissolution are used to recover metals, then metallic constituents are extracted, but structural integrity of materials is lost and additional processing is required

Engineering Contradiction:
Improvemetal recoveryVSAvoidstructural integrity
Core Design Contradiction:
Loss of substanceVSStability of the object's composition

Solution Approach 1:

The invention segments the photovoltaic module into its constituent layers through controlled delamination, separating the polymeric layers from the rigid layers (glass and photovoltaic cells) without crushing or chemically dissolving them. This maintains the structural integrity of each component for direct reuse.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention replaces mechanical crushing and chemical dissolution with a thermo-mechanical delamination process. By using controlled thermal cycling and mechanical vibrations at cryogenic temperatures, the separation is achieved through interfacial delamination rather than destruction of the materials.

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

3Ease of manufacture

If high temperature processing is used to separate layers, then complete separation is achieved, but mechanical properties of recovered materials are altered

Engineering Contradiction:
Improvelayer separationVSAvoidmechanical properties
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The invention changes the temperature parameter from high (480-540°C) to low (cryogenic temperatures), fundamentally altering the separation mechanism from thermal melting to thermal stress-induced delamination. This parameter change reduces energy consumption while achieving effective layer separation.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If conventional recycling processes are used, then materials are separated, but environmental pollution increases due to toxic substance dispersion

Engineering Contradiction:
Improvematerial separationVSAvoidpollution
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention replaces mechanical crushing and chemical dissolution with a thermo-mechanical delamination process. By using controlled thermal cycling and mechanical vibrations at cryogenic temperatures, the separation is achieved through interfacial delamination rather than destruction of the materials.

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

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 process minimizes mechanical and chemical treatment, reduces energy consumption, and allows for the immediate reuse of recovered components with preserved properties, extending their useful life and reducing environmental impact.

Implementation Method 1

a) cooling down the whole module in a cryogenic environment, for example at a temperature of -196° C.

Methodology Applied
Scientific EffectCryogenic cooling: Cryogenics

Implementation Method 2

b) imposing thermal cycles on specific zones of the module in order to generate a stress of delamination between the different layers

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

imposing thermal cycles on specific zones of the module in order to generate a stress of delamination between the different layers

Methodology Applied
Scientific EffectThermal stress: Thermal Shock

Implementation Method 4

c) imposing mechanical oscillations in resonance on the module so as to amplify the stress of delamination between the different layers

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 5

d) insufflation of a liquid under controlled pressure and flow rate so as to facilitate the separation between the different layers

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Data Source

PatentEP2973744B1Thermo-mechanical controlled cryogenic delamination process for the recovery of rigid materials coated with plastic materials
Publication Date: 2017.09.06 POLITECNICO DI BARI
  • EP2973744B1 patent drawingFigure 1
  • EP2973744B1 patent drawingFigure 2
  • EP2973744B1 patent drawingFigure 3

AI summary

The purpose of the invention is to provide a process for the recovery of raw materials fro multilayer artifacts. The process involves cryogenic conditioning of the materials to be recovered and exploits the different thermal and elastic behaviour of different layers of different material.