FR3140289A1 - METHOD FOR MECHANICAL SEPARATION OF DIFFERENT SEMICONDUCTOR, INSULATING OR METAL MATERIALS FROM A COMPONENT OR MODULE, FOR EXAMPLE PHOTOVOLTAIC, FOR THE RECYCLING OF THE LATTER - Google Patents

Abstract

The invention relates to a method for mechanically separating different materials from an electronic module at the end of its life, comprising: a) providing a mixture of first (101) and second (103) elements, in the form of pieces, each piece having three dimensions in an orthonormal frame of reference, the first elements (101) having at least one dimension of millimetric order and the second elements (103) having dimensions less than 500 μm and at least one dimension less than 50 μm, b) the arrangement of the first and second elements in a trough (1); c) the spatial separation of the first (101) and second (102) elements, respectively towards a downstream end (14a) and an upstream end (13a), by applying a mechanical vibration to the inclined trough (1). of an angle (α) between 10° and 30°. Figure 3

Description

METHOD FOR MECHANICAL SEPARATION OF DIFFERENT SEMICONDUCTOR, INSULATING OR METAL MATERIALS FROM A COMPONENT OR MODULE, FOR EXAMPLE PHOTOVOLTAIC, FOR THE RECYCLING OF THE LATTER FIELD OF INVENTION

The present invention relates to the field of recycling of components or modules formed from different materials, in particular semiconductors, insulators and/or metals, materials which must be separated to effectively recover them in whole or in part; this is particularly the case for photovoltaic modules and cells. In particular, the invention therefore relates to a process for the mechanical separation of different elements included in a photovoltaic module at the end of its life, an objective being to recover the silicon from the photovoltaic cells, separated from other elements such as glass, metals (for example example, copper, silver...), etc.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

The deployment of photovoltaic modules has been growing strongly for several decades and more recently has been increasing exponentially. It is therefore essential to develop recycling processes for end-of-life or defective modules, because they are made of precious and recoverable materials, including silicon, silver, etc.

As illustrated in the , a classic photovoltaic module is made up of different materials: aluminum (chassis), glass, plastic (polymer encapsulant and membrane), silicon (photovoltaic cells), which together account for approximately 99% of the total weight. There are also small quantities of copper, silver, lead, tin and zinc for soldering and connectors.

Photovoltaic grade silicon has a very high purity ranging from 6N (or 99.99999%) up to 11N by weight. It is important, in the context of recycling and revaluation of silicon cells from a photovoltaic module, to maintain this purity as much as possible. This high purity recommendation therefore requires particularly high sorting efficiency.

When a photovoltaic module must be recycled, it is usually broken into pieces, for example by implementing thermal treatments (pyrolysis) or mechanical treatments (notably water jet).

Processes exist to separate these pieces according to the nature of their material; they are based on optical separation, electrostatic separation, separation by eddy currents or even mechanical separation.

At the scale of the photovoltaic cell, it is particularly necessary to separate the silicon and the silver lines which form the electrical contacts. There are chemical and/or mechanical treatments to detach these silver lines from the pieces of silicon. We can in particular refer to document FR3096833 which proposes a recycling process authorizing the physical division between the silicon and the silver lines of a photovoltaic cell.

Obtaining a mixture of pieces of silicon and pieces of silver, it is not always easy to sort and effectively segregate pieces of materials of different natures.

In the field of recycling, particularly photovoltaic cells, there is therefore a strong advantage in simplifying and making separation processes more reliable in order to recycle as large a part as possible of the materials forming the cells, these materials being able to pollute each other. They are reinjected mixed into a recovery chain.

OBJECT OF THE INVENTION

The present invention relates to a process for separating different materials (in particular semiconductors, insulators and/or metals) forming components or modules, so as to effectively recycle and recover all or part of said materials. The method uses a trough having an inclination between 10° and 30° relative to the horizontal: elements composed of different materials are arranged in the trough and, subjected to mechanical vibration, undergo spatial separation in a zone upstream (on the high side) or downstream (on the low side) of the trough, depending on the physical characteristics of said elements.

The invention relates in particular to the recycling of photovoltaic cells and is applicable with excellent efficiency to the separation of silver and silicon.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a method for mechanical separation of different semiconductor, insulating or metallic materials from an electronic component or module at the end of its life, comprising the following steps:

a) the supply of a mixture of first elements and second elements, in the form of pieces, each piece having three dimensions in an orthonormal frame of reference, the first elements having at least one dimension of millimetric order and the second elements having dimensions less than 500μm and at least one dimension less than 50μm,
b) the arrangement of the first elements and the second elements in a central zone of a trough, said trough having the shape of a tray, solid in the central zone, extending in a main plane, and having lateral edges;
c) the spatial separation of the first elements and the second elements, by applying a mechanical vibration to the trough, said trough being inclined so that the main plane forms an angle of inclination of between 10° and 30° with a substantially horizontal plane and so as to define an upstream zone and a downstream zone with respect to the central zone of the trough, the second elements and the first elements, subjected to mechanical vibration, being routed respectively towards the upstream zone and towards the downstream area of the trough.

• l’angle d’inclinaison est compris entre 10° et 25° ;
• le composant ou module électronique est une cellule photovoltaïque, à savoir un empilement comprenant une couche de silicium, des couches et des lignes métalliques ;
• l’étape a) comprend la division de la cellule photovoltaïque par traitement mécanique ou chimique, de manière à détacher les lignes métalliques, le premier matériau composant les premiers éléments étant le silicium, le deuxième matériau composant les deuxièmes éléments étant l’argent des lignes métalliques ;
• les premiers éléments présentent une longueur et une largeur comprises entre 1mm et 20mm et une épaisseur de l’ordre de 150μm ;
• les deuxièmes éléments présentent une longueur inférieure à 500μm, et une largeur et une épaisseur inférieures à 50μm ;
• le procédé de séparation mécanique comprend une étape d) de récupération des éléments, lorsqu’ils passent au-delà d’une extrémité amont ou d’une extrémité aval de l’auge ;
• le procédé de séparation mécanique comprend une étape d) de récupération des éléments dans la zone amont ou dans la zone aval de l’auge, un ou plusieurs orifices étant aménagé(s) dans le plateau de l’auge dans ladite zone amont et/ou ladite zone aval ;
• la vibration mécanique à l’étape c) est appliquée à l’auge par l’intermédiaire d’un système vibrant, solidaire de l’auge, la vibration mécanique présentant une fréquence comprise entre 40 et 60 Hz ;
• la vibration mécanique appliquée à l’auge est associée à un mouvement rectiligne d’amplitude comprise entre 1mm et 20mm ;
• le mouvement rectiligne s’opère selon un axe incliné de 10° à 30° par rapport au plan principal, ledit axe et l’axe longitudinal de l’auge étant inclus dans un plan normal au plan principal ;
• l’auge est formée en un matériau choisi parmi l’acier, la céramique, le quartz ou le silicium.

According to advantageous characteristics of the invention, taken alone or in any feasible combination:

• the tilt angle is between 10° and 25°;
• the electronic component or module is a photovoltaic cell, namely a stack comprising a silicon layer, layers and metal lines;
• step a) comprises the division of the photovoltaic cell by mechanical or chemical treatment, so as to detach the metal lines, the first material composing the first elements being silicon, the second material composing the second elements being silver from the lines metallic;
• the first elements have a length and width of between 1mm and 20mm and a thickness of around 150μm;
• the second elements have a length of less than 500 μm, and a width and a thickness of less than 50 μm;
• the mechanical separation process comprises a step d) of recovering the elements, when they pass beyond an upstream end or a downstream end of the trough;
• the mechanical separation process comprises a step d) of recovering the elements in the upstream zone or in the downstream zone of the trough, one or more orifices being provided in the tray of the trough in said upstream zone and/ or said downstream zone;
• the mechanical vibration in step c) is applied to the trough via a vibrating system, integral with the trough, the mechanical vibration having a frequency of between 40 and 60 Hz;
• the mechanical vibration applied to the trough is associated with a rectilinear movement of amplitude between 1mm and 20mm;
• the rectilinear movement takes place along an axis inclined by 10° to 30° relative to the main plane, said axis and the longitudinal axis of the trough being included in a plane normal to the main plane;
• the trough is formed from a material chosen from steel, ceramic, quartz or silicon.

Other characteristics and advantages of the invention will emerge from the detailed description which follows with reference to the appended figures:

There presents an exploded view of the constituents of a classic photovoltaic panel;

There presents a trough implemented in the mechanical separation process according to the present invention, (a) in top view and (b) in side view;

There has a trough and a separation between first and second elements, in accordance with the present invention.

The figures are schematic representations in which the relative dimensions between the different elements/components are not necessarily respected.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to a method for mechanical separation of different semiconductor, insulating or metallic materials from an electronic component or module at the end of its life.

As will be specified later, the electronic component or module can for example be one (or more) photovoltaic cell(s) 110, for example from a photovoltaic module 100. The materials considered are therefore in particular silicon and money; they compose different elements 101,103, in the form of pieces, which constitute objects to be separated and sorted.

• Une étape a) de fourniture de deux types d’éléments 101,103 différents à trier,
• Une étape b) de disposition desdits éléments 101,103 dans l’auge 1,
• Une étape c) de séparation spatiale des deux types d’éléments 101,103.

Generally speaking, the method according to the invention is based on the spatial separation of said elements 101,103, in a trough 1 inclined adequately and subjected to a particular mechanical vibration. It typically includes:

• A step a) of supplying two different types of elements 101,103 to sort,
• A step b) of arranging said elements 101,103 in the trough 1,
• A step c) of spatial separation of the two types of elements 101,103.

The trough 1 has the shape of a solid plate, at least in a central zone 12, extending along a longitudinal axis A, and comprising lateral edges 11 ( ). The trough 1 is typically formed from a material chosen from steel, ceramic, quartz or silicon; the hardness of the material of trough 1 must approach or exceed the hardness of the materials of the elements 101,103 to be sorted, so that the latter do not excessively damage it. The top is flat and smooth.

The lateral dimensions of the plate can vary from a few centimeters to several meters, depending on the quantity of material that we wish to process. For example, trough 1 can have a length, along the longitudinal axis A, of approximately 1m and a width of around 50cm. The height of the side edges 11 is typically chosen from around 1cm to a few cm.

A distribution device 5 can be arranged above the central zone 12 of the trough 1, so as to gradually introduce the elements 101,103 onto the plate of the trough 1.

The spatial separation takes place due to the movement of certain elements 103 towards the higher part (called the upstream zone 13) of the trough 1 while other elements 101 move towards the lower part (called the downstream zone 14) . Such separation is made possible due to the different geometry (plane shape, powder form, etc.) of the elements 101,103 present on the trough 1, in combination with the inclination and the vibratory movement of the trough 1 .

In the context of the present invention, the angle of inclination α of the trough 1 is between 10° and 30° (+/-0.5°). Note that the angle of inclination α corresponds to the angle formed between a horizontal plane and a main plane defined by the plate of trough 1. A particular embodiment will then be detailed, in which ranges of angles d More precise inclination α are proposed.

The mechanical vibration is advantageously applied to the trough 1 via a vibrating system 2, integral with the trough 1. The mechanical vibration typically has a frequency between 40 and 60 Hz, for example 50 Hz. It can be associated with a rectilinear movement along an axis parallel or normal to the main plane, or forming any angle with said main plane. Mechanical vibration can also be associated with an elliptical movement, which can take place in the main plane, in the horizontal plane or in any other plane. The amplitude of these different possible movements is preferably between 1mm and 20mm.

According to a preferred variant, the vibratory movement is rectilinear, along an axis forming an angle of between 10° and 30° with the main plane (plane of the tray of trough 1), it being understood that the main plane forms an angle of inclination α between 10° and 30° with the horizontal plane and that the axis of the vibratory movement and the longitudinal axis A belong to the same plane normal to the main plane.

The method comprises a step d) of recovering the two types of elements 101,103, when they pass respectively beyond an upstream end 13a or a downstream end 14a of the trough 1. For this, containers 3 , 4 can be arranged below each of the ends 13a, 14a.

According to a possible variant, one or more orifices (not shown) are arranged in the plate of the trough 1 in the upstream zone 13 and/or in the downstream zone 14, to allow one and the other to pass respectively. other of the two types of elements 101,103 separated; each type of element 101,103 can then fall into a dedicated container 3,4, arranged under the orifice(s).

According to a particular embodiment of the invention, the method of mechanical separation of different semiconductor, insulating or metallic materials from an electronic component or module at the end of its life, comprises a step a) of supplying a mixture of first elements 101 and second elements 103, in the form of pieces, each piece having three dimensions (length L, width l, thickness e) in an orthonormal frame of reference ( ).

Each first element 101 has at least one millimetric dimension, typically greater than or equal to 1mm, or even 2mm. According to an advantageous variant, each first element 101 has a generally flat shape: its lateral dimensions (length L, width l) are therefore greater than its thickness e. The first elements 101 are thus characterized by at least one millimeter dimension and advantageously, a form factor (called first form factor) greater than 6, or even greater than 10, 20, 50, or even more.

Each second element 103 has dimensions less than 500 μm and at least one dimension less than 50 μm. Typically the second elements 103 are in powder form, in other words, in the form of very fine particles. These elements 103, in addition to their very small dimensions, can be in a substantially cylindrical form, the section of the cylinder can then be defined by a width l and a thickness e, or by a diameter ϕ if it is circular.

Step b) includes the arrangement of the first elements 101 and the second elements 103 in a central zone 12 of the trough 1. Remember that the central zone 12 of the trough 1 is not limited to the center of the plate, but is considered extended towards each of the upstream 13a and downstream 14a ends. The introduction of elements 101,103 onto the plate can therefore take place more or less near/far from said upstream 13 and downstream 14 zones, while remaining in the central zone 12.

In step c), the spatial separation of the first elements 101 and the second elements 103 occurs, by application of a mechanical vibration (as previously described) to the trough 1, which is inclined with an angle of inclination α between 10° and 30° (+/-0.5°). The first elements 101 are then routed to the downstream zone 14 (lowest part) of the trough 1, while the second elements 103 are routed to the upstream zone 13 (highest part) ( ).

Advantageously, the angle of inclination α of the trough 1 is between 15° and 25° (+/-0.5°), for example around 20°.

The spatial separation of the first 101 and the second 103 elements is favored by the fact that, in this range of inclination of the trough 1, the balance of forces (friction, gravity, reaction of the trough on the elements) is such that it causes the sliding of the first elements 101 (for example planes) towards the lower part of the trough 1 (downstream zone 14). The second elements 103, similar to dust, are very highly volatile and subject to air currents created by the vibratory movements of the trough 1; these air currents allow the second elements 103 to move up along the plate. When they are not lifted by air currents, the second elements 103 are retained by the micro-asperities of the trough 1.

In this embodiment, the electronic component or module is for example a photovoltaic cell 110, namely a stack comprising in particular a silicon substrate, layers and metal lines. This cell 110 can come from a photovoltaic module 100 ( ) at the end of its life, dislocated by pyrolysis or by mechanical techniques (water jet, etc.). The photovoltaic cell 110 can also come from production scraps.

Step a) can then include the division of the photovoltaic cell 110 by mechanical treatment (exfoliation) and/or chemical, so as to detach the metal lines: the first material composing the first elements 101 is then silicon (totally or mainly ), the second material making up the second elements 103 is the silver of the metal lines.

The first elements 101 can have a length L and a width l of between 1mm and 20mm and a thickness e of around 150μm. The second elements 103 may have a length L less than 500 μm and a width l and a thickness e (or a diameter ϕ) less than 50 μm. These are in particular the size ranges of the first silicon elements 101 and the second silver elements 103 (metal wires) recovered from a photovoltaic cell 110.

The invention is not limited to the embodiment described and alternative embodiments can be made without departing from the scope of the invention as defined by the claims.

In particular, the mechanical separation process can be applied to the recycling of any kind of electronic component at the end of its life, and to elements composed of materials other than silicon and silver, as long as the respective shapes of the elements, in combination with the conditions of inclination and vibration of the trough, comply with the prerequisites set out in this description.

Claims (10)

Process for the mechanical separation of different semiconductor, insulating or metallic materials from an electronic component or module at the end of its life, comprising the following steps:
a) providing a mixture of first elements (101) and second elements (103), in the form of pieces, each piece having three dimensions in an orthonormal frame of reference, the first elements (101) having at least one dimension of millimeter order and the second elements (103) having dimensions less than 500 μm and at least one dimension less than 50 μm,
b) the arrangement of the first elements (101) and the second elements (103) in a central zone (12) of a trough (1), said trough (1) having the shape of a plate, solid in the central zone, s 'extending in a main plane, and having lateral edges (11);
c) the spatial separation of the first elements (101) and the second elements (103), by applying a mechanical vibration to the trough (1), said trough (1) being inclined so that the main plane forms an angle of inclination (α) between 10° and 30° with a substantially horizontal plane and so as to define an upstream zone (13) and a downstream zone (14) relative to the central zone (12) of the trough ( 1), the second elements (103) and the first elements (101), subjected to mechanical vibration, being conveyed respectively towards the upstream zone (13) and towards the downstream zone (14) of the trough (1). Mechanical separation process according to the preceding claim, in which the angle of inclination is between 10° and 25°. Mechanical separation method according to one of the preceding claims, in which the electronic component or module is a photovoltaic cell, namely a stack comprising a silicon layer, layers and metal lines. Mechanical separation method according to the preceding claim, in which step a) comprises the division of the photovoltaic cell by mechanical or chemical treatment, so as to detach the metal lines, the first material composing the first elements (101) being silicon , the second material making up the second elements (103) being the silver of the metal lines. Mechanical separation process according to one of the preceding claims, in which:
- the first elements (101) have a length (L) and a width (l) of between 1mm and 20mm and a thickness (e) of the order of 150μm;
- the second elements (103) have a length (L) less than 500 μm, and a width (l) and a thickness (e) less than 50 μm. Mechanical separation process according to one of the preceding claims, comprising:
- a step d) of recovering the elements (101, 103), when they pass beyond an upstream end (13a) or a downstream end (14a) of the trough (1), or
- a step d) of recovering the elements (101,103) in the upstream zone (13) or in the downstream zone (14) of the trough (1), one or more orifices being provided in the plate of the trough trough (1) in said upstream zone (13) and/or said downstream zone (14). Mechanical separation method according to one of the preceding claims, in which the mechanical vibration in step c) is applied to the trough (1) via a vibrating system (2), integral with the trough (1), the mechanical vibration having a frequency between 40 and 60 Hz. Mechanical separation method according to one of the preceding claims, in which the mechanical vibration applied to the trough (1) is associated with a rectilinear movement of amplitude between 1mm and 20mm. Mechanical separation method according to the preceding claim, in which the rectilinear movement takes place along an axis inclined by 10° to 30° relative to the main plane, said axis and the longitudinal axis (A) of the trough (1) being included in a plane normal to the main plane. Mechanical separation method according to one of the preceding claims, in which the trough (1) is formed of a material chosen from steel, ceramic, quartz or silicon.