Field of the invention
5
The subject matter of the invention is a photovoltaic module encapsulant based on
an ethylenelallyl acrylate copolymer in which no crosslinking agent is present
(peroxides or isocyanates or any other component having a crosslinlting function). The
present invention also relates to a photovoltaic module, or to the use of this encapsulant
10 composition in such a module, comprising, apart from the encapsulant layer, at least one
adjacent layer forming a "front sheet" or "back sheet", more generally these three
successive layers: "front sheet", encapsulant and "back sheet".
Global warming, related to the greenhouse gases given off by fossil fuels, has led
to the development of alternative energy solutions which do not emit such gases during
15 the operation thereof, such as, for example, photovoltaic modules. A photovoltaic
module comprises a "photovoltaic cell", this cell being capable of converting light
energy into electricity.
Many types of photovoltaic panel structures exist.
A conventional photovoltaic cell has been represented in figure 1; this
20 photovoltaic cell 10 comprises cells 12, a cell containing a photovoltaic sensor 14,
generally based on silicon treated in order to obtain photoelectric properties, in contact
with electron collectors 16 placed above (upper collectors) and below (lower collectors)
the photovoltaic sensor. The upper collectors 16 of a cell are connected to the lower
collectors 16 of another cell 12 via conducting bars 18, generally composed of an alloy
25 of metals. All these cells 12 are connected to one another, in series and/or in parallel, to
form the photovoltaic cell 10. When the photovoltaic cell 10 is placed under a light
source, it delivers a direct electric current which can be iecovered at the terminals 19 of
the cell 10.
With reference to figure 2, the photovoltaic module 20 comprises the photovoltaic
30 cell 10 of figure 1 encased in an "encapsulant", the latter being composed of an upper
part 22 and of a lower part. An upper protective layer 24 (known under the term "Front
sheet", used in the continuation) and a protective layer at the back of the module
(known under the term "bacli sheet", also used in the continuation) 26 are positioned on
either side of thc encapsulated cell.
Impact and moisture protection of the photovoltaic ccll 10 is provided by the
upper protective layer 24, gcnerally made of glass.
5 The back sheet 26, for example a multilayer film based on fluoropolymer and on
polyethylene terephthalate, contributes to the moisture protection of the photovoltaic
module 20 and to the electrical insulation of the cells 12 in order to prevent any contact
with the external environment.
The encapsulant 22 has to perfectly match the shape of the space existing between
10 the photovoltaic cell 10 and the protective layers 24 and 26 in order to avoid the
presence of air, which would limit the output of the photovoltaic modulc. The
encapsulant 22 must also prevent contact of the cells 12 with atmospheric oxygen and
water, in order to limit the corrosion thereof. The upper part of the encapsulant 22 is
included between the cell 10 and the upper protective layer 24. The lower part of the
15 encapsulant 22 is included between the cell 10 and the baclc sheet 26.
In the presence of solar radiation, heating occurs inside the solar module and
temperatures of 80°C (or more) may be reached, which necessitates that the layers be
perfectly bonded to one another throughout the life cycle of the module.
20 State of the art
Currently, the majority of the photovoltaic encapsulation market corresponds to
formulations based on an EVA to which a peroxide, a silane and various functional
additives are added.
EVA exhibits many qualities and properties advantageous for this application.
25 This is because it confers mainly very good properties of transparency, of mechanical
strength and of resistance to aging and generally excellent thermomechanical and
mechanical properties. Furthermore, this thermoplastic is relatively inexpensive, so that
its use for this application has become virtually inescapable.
Nevertheless, the type of encapsulant based on EVA, with peroxide and silane,
30 exhibits two major disadvantages.
First of all, the use of a crosslinking agent, namely the peroxide, exhibits the
disadvantage of relatively lengthy processing, nccessary in accordance with the
reactivity kinetics of the peroxide, the current cycle time, for the manufacture of a
lnodule using such an encapsulant, being bctwcen 15 and 45 minutcs. Nevertheless,
currently, the use ol: a crosslinking agent is necessary, in particular for EVA, in ordcr to
confer, on the latter, better thermomechanical properties and physicochernical
characteristics and also in order to ensure the grafting of the silane to the polymer
5 chains.
As regards the EVA, when the environmental conditions have deteriorated, that is
to say when it ages under hot and damp conditions (DHT (damp heat test): 85OC/85%
RH (Relative Humidity)), this component is subject to hydrolysis which brings about
the appearance of acetic acid, a source of yellowing of the encapsulant and of conosion
10 of the metal connections of the photovoltaic module.
A person skilled in the art might envisage the replacement ol: the EVA by an
ethylenelalkyl acrylate copolymer but this solution, although admittedly avoiding the
specific problems related to EVA when the latter is present in a difficult environment,
does not make it possible to obtain a correct photovoltaic module. This is because,
15 during the lamination, numerous bubbles are formed during the crosslinkmg due to the
peroxide, present in significant amounts.
Furthermore, the document WO 200609591 1 provides a solution by the use of a
formulation based on an ethylenelalkyl acrylate copolymer, the melting point of which
(T in "C), obtained according to the standard JIS K 7121, would correspond to the
20 following formula: -3.0Xt125 > T >-3.0X+109, the component X representing the
molar content of the polar comonomer (acrylate). Furthermore, this document provides
for the combining of this copolymer with a silane in order to introduce the adhesive
properties on the glass.
Ilowever, such a formulation would not make it possible to obtain an cncapsulant
25 which is effective over the long term. This is because the silane exhibits the
disadvantage of not making possible a good level of adhesion to the glass when it is not
chemically bonded to the polymer.
Thus, an encapsulation solution based on an alternative component to EVA but
30 exhibiting properties which are just as advantageous, while not using crosslinking
agents, is currently being sought.
This solution should furthermore make possible the use of an adhesion promoter,
such as a silane, making possible in particular the attachment to the walls of the front
sheet, that is to say to a component made of glass-ccramic or synthetic glass
(conventionally PMMA), and maintaining good adhesive properties on the front shcct
during its use.
5 Brief description of the invention
It has bcen found, by the applicant company, after various experiments, that a
composition based on an ethylenelalkyl acrylate copolymer and on silane could, without
use of any crosslinking agent, exhibit highly satisfactory thermomechanical properties
10 and physicochemical characteristics when it was combined with a hnctionalized
polyolefin of a very specific type.
This very specific polyolefin consists of the ethylenelalkyl acrylatelmaleic
anhydride terpolymer.
Thus, the present invention relates to a photovoltaic module encapsulant intended
to encase a photovoltaic cell, consisting of a composition not comprising any
crosslinking agent and comprising:
- an ethylenelalkyl acrylate copolymer, said copolymer representing between 70%
and 96% of the weight of said composition;
20 - a silane, representing between 0.1% and 2% of the weight of said composition;
characterized in that it additionally comprises an ethylenelacrylic esterlmaleic
anhydride or glycidyl methacrylate terpolymer, said terpolymer representing from 2% to
29.9% of the weight of said composition.
The composition according to the invention first exhibits the following
advantages:
- the impossibility of the appearance of acetic acid, more generally of any acid,
during its use, whatever the environmental conditions;
- a very great latitude regarding the extrusion parameters of the composition film
30 and a significant saving in time with regard to the laminatjon stage;
- the maintenance of excellent adhesive properties of the composition throughout
the lifetime of the composition, in particular in its use as encapsulant of a photovoltaic
module;
- the maintenance of exccllcnt thercnornecbanical properties and of
physicochemical characteristics, at least as satisfactory as the cui~ensto lution based on
EVA (crosslinking agent and silane).
Other characteristics and distinctive features of the primary mixture of the
invention are presented below:
- advantageously, the abovesaid terpolymer represents between 8% and 22% of
the weight of said composition;
- preferably, for the abovesaid copolymer, the content by weight of ethylene is
10 between 60% and 85%, preferably between 70% and 84%, and the content by weight of
alkyl acrylate is between 15% and 40%, preferably between 16% and 30%;
- advantageously, the silane consists of an epoxysilane or an aminosilane;
- in the latter case, advantageously, the silane consists of (3-glycidyloxypropy1)
triethoxysilane;
15 - the abovesaid copolymer is present at between 75% and 95% by weight of said
composition;
- according to one possibility offered by the invention, the composition consi~ts
solely of the abovesaid copolymer, the abovesaid terpolymer and the abovesaid silane;
- according to one embodiment, the composition additionally comprises additives
20 intended to confer additional specific properties, in particular plasticizers, adhesion
promoters, UV sk~bilizersa nd absorbers, antioxidants, flame retardants andlor fillers.
The invention also relates to the use of the encapsulant as described above in a
photovoltaic module.
25 Finally, the invention relates to a photovoltaic module comprising a structure
consisting of a combination of at least one encapsulant and a front sheet or back sheet,
characterized in that the encapsulant is as described above.
Description of the appended figures
30
l'he description which follows is given solely by way of illustration and without
implied limitation with reference to the appended figures, in which:
figurc 1, which is already described, represents an example of a photovoltaic cell,
the parts (a) and (b) being 1/4 views, the part (a) showing a cell before conncction and
the part (b) a vicw after connection of 2 cells; the part (c) is a top view of a complete
photovoltaic cell.
5 Figure 2, which is already described, represents a cross section of a photovoltaic
module, the "conventional" photovoltaic sensor of which is encapsulated by an upper
encapsulant film and a lower encapsulant film.
Detailed description of the invention
As regards the ethylene/alkyl acrylate copolymer, it is a component well known to
a person skilled in the art. The distinctive features specific to this copolymer, in the
context of the present invention, originate essentially from the proportions by weight of
ethylene and alkyl acrylate, the content by weight of ethylene being between 60% and
85%, preferably between 70% and 84%, and the content by weight of alkyl acrylate
15 being between 15% and 40%, preferably between 16% and 30%. This copolymer will
preferably be obtained according to a "tubular" polymerization process, making it
possible to obtain a copolymer having improved thermal properties (in comparison with
the same copolymer obtained according to the "autoclave" process).
As nonlimiting example, the applicant company makes use commercially of a
20 component known as LOTRYL~w, hich is an ethyleneialkyl acrylate copolymer.
A person skilled in the art fully knows how to produce/manufacture such a
copolymer, according to the different amounts of each of the two monomers. In the
continuation, the invention is presented with an ethyleneialkyl acrylate copolymer of
specific type but it has becn demonstrated by the proprietor that the encapsulant
25 composition according to the invention meets the objectives set when the copolymer
varies within the ranges of content of ethylene and of alkyl acrylate which are defined
above, possibly in a slightly better way when said copolymer exhibits contents of
ethylene and of alkyl acrylate which are chosen within the ranges preferrcd for these
two monomers.
As regards the silane, these arc chemical compounds which make possible thc
adhesion interactions between the encapsulant and the glass. Mcntion may be made, as
examples of silane, oS aminosilanes and epoxysilanes or any other silane carrying a
functional group which is reactive with respect to the terpolymer. Preferably, the silane
5 in the composition according to the invention is glycidyloxypropyltriethoxysilane.
Nevertheless, equivalent or substantially equivalent results would be obtained by
choosing another silane of the family of the epoxysilanes or aminosilanes.
As regards the ethylenelacrylic esterlmaleic anhydride terpolymer, this reactive
10 component is well known to a person skilled in the art and it does not present any
difficulties for its manufacturelpreparation.
The composition forming the encapsulant according to the invention can comprise
a certain number of additives intended to confer additional specific properties.
15 Plasticizers can be added in order to facilitate the processing and to improve the
productive output of the process for the manufacture of the composition and of the
structures. Mention will be made, as examples, of paraffinic, aromatic or naphthalenic
mineral oils, which also make it possible to improve the adhesiveness of the
composition according to the invention. Mention may also be made, as plasticizer, of
20 phthalates, azelatcs, adipates or tricresyl phosphate.
Adhesion promoters, although not necessary, can advantageously be added in
order to improve the adhesiveness of the composition when the adhesiveness has to be
particularly high. The adhesion promoter is a nonpolymeric ingredient; it can be
organic, crystalline, inorganic and more preferably semiinorganic semiorganic. Mention
25 may be made, among these, of titanates.
In this specific application of the composition with photovoltaic modules, as UV
rad?ation is capable of resulting in a slight yellowing of the composition used as
encapsulant of said modules, UV stabilizers and UV absorbers, such as benzotriazole,
benzophenone and other hindcrcd amines, can be added in order to ensure the
30 transparency of the encapsulant during its IiSetime. These cotnpounds can, for example,
be based on benzophenone or on ben~otriazole.T hey can be added in amounts or less
than 10% by weight of the total weight of the composition and preferably from 0.05%
to 3%.
It will also be possible to add antioxidants in order to limit the yellowing during
5 the manufacturing of the encapsulant, such as phosphorus-based compo~~nds
(phosphonites andlor phosphites) and hindered phenolic compounds. These antioxidants
can be added in amounts of less than 10% by weight of the total weight of the
composition and preferably from 0.05% to 3%.
Flame retardants can also be added. These retardants can be halogenated or
10 nonhalogenated. Among the halogenated retardants, mention may be made of
brominated products. Use may also be made, as nonhalogenated retardant, of
phosphorus-based additives, such as ammonium phosphate, polyphosphate, phosphinate
or pyrophosphate, melamine cyanurate, pentaerythritol, zeolites and the mixtures of
these retardants. The composition can comprise these retardants in proportions ranging
15 from 3% to 4096, with respect to the total weight of the composition.
It is also possible to add pigments, such as, for example, titanium dioxide, dyeing
compounds or brightening compounds in proportions generally ranging from 5% to
IS%, with respect to the total weight of the composition.
Fillers, in particular inorganic fillers, can also be added to improve the
20 thermomechanical strength of the co~n~positionE.x amples which will be given are,
without implied limitation, silica, alumina or calcium carbonates or carbon nanotubes or
also glass fibers. Use may also be made of modified or nonmodified clays which are
mixed at the nanometric order; this makes it possible to obtain a more transparent
composition.
25
Preparation of the e n c a u s ~ s u l a nfilmt ac cordinthe
inventiou (intended to be incorporated in a photovoltaic module):
Conventionally, a crosslinking is necessary in order to adjust the
thermomechanical properties of the EVA-based encapsrrlant, in particular when the
30 temperature becomes very high. In this case, in the context of the present invention, the
crosslinking is not necessary and,only conventional chemical interactions and reactions
take place between the functionalized polyolelin (the tcrpolymer) and the ethylenelalkyl
acrylate copolynler and between the functionalized polyolefin and the silane.
With regard to the aspects targeicd above, the handhooli entitled "Handbook of
Polymer Foams and Technology", in particular on pages 198 to 204, provides additional
5 instructions to which a person skilled in the art may refer.
As regards the aspects of the invention relating to the use of the thermoplastic
composition in a photovoltaic module, a person skilled in the art may refer, for examplc,
to the "Handbook of Pho:ovoltaic Science and Engineering", Wiley, 2003. This is
because the composition of the invention can be used as encapsulant or encapsulant-
10 back sheet in a photovoltaic module, the structure of which is described in connection
with the appended figures.
Materials em~loyedto form the formulations tested:
~ottyl@20 MA08: ethylenelmethyl aerylaie copolymer, the aerylate content of
15 which is 20% by weight of the copolymer and the MFI of which is 8 g/10 min (19OoC,
2.13 kg). It can be obtained according to:
- a tubular process: Melting point = 96°C
- an autoclave process: Melting point = 75°C
In the tables of results presented below, this ~ o t r ~ ils' d enoted by the initials 20MA08T
20 when it was obtained by the tubular process and 20MA08A when it was obtained by the
autoclave process.
~otryl@24 MA02: ethylenelmethyl acrylate copolymer, the acrylate content of
which is 24% by weight of the copolymer and the MFI of which is 2 g110 min (19O0C,
2.13 kg). It can be obtained according to:
25 - a tubular process: Melting point = 93°C
- an autoclave process: Melting point = 68°C
In the tables of results presented below, this ~otryl@is denoted by the initials 24MA02T
when it was obtained by the tubular process and 24MA02A when it was obtained by the
autoclave process.
30 ~otader@34 10: ethylenelbutyl acrylatelmaleic anhydride terpolymer, the acrylate
content of which is 17% by weight of the terpolymer, the anhydride content of wllich is
3.1% by weight of the terpolymer and the MFI of which is 5 g/10 mln (190°(:, 2.1 3 kg).
In thc tables of results presented below, this ~otadel" is denoted by thc term 341 0.
~ y n a s ~ l a nG@LY EO: glycidyloxypropyltriethoxysilane sold by Evonik. It is a
silane having a reactive epoxide functional group and a hydrolyzable triethoxysilyl
5 group. In the tables of results presented below, this silane is denoted by the initials
G1,YEO.
~vatane@33 45PV: ethylenelvinyl acetate copolymer, the acetate content of
which is 33% by weight of the copolymer and the MFI of which is 45 gilO min (190°C,
2.13 kg). In the tables of results presentcd below, this Evatanem is denoted by the initials
10 3345PV.
~ ~ n a s y l a n @ME MO: 3-MethacryloyloxypropylTrimethoxySilane sold by
Evonik. In the tables of results presented below, this silane is denoted by the initials
MTS.
~ u ~ e r o xTB@E C: 00-terl-butyl 0-(2-ethylhexyl) monoperoxycarbonate sold by
15 the applicant Arkema, denoted TBEC in the continuation.
Production of the tested films and formulations:
Preparation of the films:
The encapsulant films are obtained by extrusion of impregnated polymer granules:
20 the silanes and, if appropriate, the peroxide are added by impregnation of the Lotryl or
Evatane granules. Granules and liquid are placed in a flask and the flask is positioned
on a roll mixer for approximately 3 hours at a speed of 60 rotations per minute.
After impregnation, these granules, and also optionally additional granules, are
placed in the introduction hopper of a slit extruder with a width of 10 cm (centimeters).
25 The extrusion is carried out at a temperature appropriate to the composition; thus,
for the counterexample based on Evatane and Luperox TBEC (composition ECl), this
temperature is limited to 90°C, as, above this temperature, the peroxide would
dccompose.
In the case of formulations as described in this invention, the terriperaturz is
30 limited only by the thermal propeltics of the polymer used. However, it will be
appropriate to carry out this extrusioll at a temperature of between 100°C and 220°C.
'This extrusion niakcs it possiblc to obtain a rcel or film, the drawing of which at
the extruder outlet is adjusted so as to obtain a film with a thickness oTbetwecn 350 and
550 pm (micrometers).
5 Preparation of the tcst modules:
In order to characterize the formulations, test modules are obtained by hot
lamination.
The structure of a tcst modulc varied according to the characterizations to be
carried out:
10 - Measurement of creep and of optical properties by transmission: Glass
(4 mm)/Encapsulant film1Glass (4 mm)
- Measurement of optical properties by reflection: Glass (4 mm)/Encapsulani
film/KF'K back sheet (PVDFIPETIPVDF)
- Measurement of adhesion: Glass (4 mm)/Encapsulani film1Apolhya back sheet
The laminator used is provided by Penergy. The lamination conditions (Duration,
Temperature T and Pressures of the upper and lower chambers, respectively VUp and
Vdowna)r c dependent on the composition of the laminated films.
Thus, in ihc case of a "conventional" formulation, the cycle observed is the
20 following (total duration: 20 minutes):
/ Duration (s) / T (OC) / Vup (mbar) / Vdowll War) /
In the case of a formulation as described in tlic present invention, the cycle
observed is the following (total duration: 8 minutes):
Tests carried out on the test specimens:
5 The present invention is illustrated in more detail by the following nonlimiting
examples.
The compositions denoted El, E2, E3 and E4 in the table below are compositions
in accordance with the invention while the compositions EC1, EC2, EC3 and EC4 are
compositions according to the prior art and/or not in accordance with the present
10 invention.
The examples of the composition according to the invention all exhibit the same
thicknesses but it is clearly understood that a person skilled in the art can vary them as a
[unction of the application of the photovoltaic module and of the performance of the
15 latter.
It will also be noted that the test specimens targeted abovc exhibit identical
amounts of silane, fixed substantially at 0.25% of the weight of the composilion.
Nevertheless, additional tests have made it possible to identify that the amount of silane
in the composition could be representcd between 0.1% and 2% by weight of said
composition.
Aging of the structures:
5 An accelerated aging of the structures is carried out by DHT ("Damp Heal Test"). All
the structures are placed in a climate-control chamber regulated at 85°C and 85% RH
(relative humidity). This aging lasts 2000 hours. The change in the yellowness index
(YI) of the modules is monitored during this DHT.
10 Measurement of the yellowness index YI:
The yellowness index YI is measured on glasslencapsulant/back sheet structures using a
spectrocolorimeter of the Minolta brand and according to the standard ASTM E313.
The back sheet used for this measurement is a KPK (PVDFIPETIPVDF). The
measurement conditions are as follows:
15 Wavelength: 360 nm - 740 nm (nanometers)
Illuminant: C
= Angle: 2"
Measurement opening: MAV 8 mm (millimeters)
Background: "Cera" white sheet
20 The value selected for this test is the change in the YI, denoted AYI, after aging for
2000 h under DHT conditions.
AYI = YI200oh - YIOh
Creep test:
25 The creep test is carried out on glasslencapsulantlglass structures (with glass sheets
having a length L = 70 mm). After lamination, the test modules are placed on a metal
structure forming an angle of 70" with the horizontal. Each module is held back by an
edge covering a portion of the thickness of the first glass layer.
This structure is placed in an oven at 100°C. Creep may be observed under the weight
30 of the second glass layer. The creep value measured is thus the distance traveled by the
second glass sheet after 500 hours under these conditions. This distance is between
0 mm (no creep) and 70 mm (complete creep, separation of thc structure).
Adhesion test on a glass sheet.
The lcvel of adhcsion between the encapsulant and the glass is measured on
glasslencapsulantlbacli sheet structures fiom a 90" peel test carried out at 50 inmnlmin
(millimeters per minute) on a Zwick 1445 universal testing machine. The back sheet
5 used for this measurement is a monolayer consisting of ~ ~ o l h y am"a nufactured and
sold by the applicant. The measurement conditions are as follows:
Rate of displacement of the crosspiece: 50 ~nmlmin
Test specimen cut-out width: 10 mm
* Peel angle: 90"
10 The adhesion result is expressed in Nlmm.
Tests on the encapsulant were also carried out in order to confirm that this novel
structure retains excellent properties, that is to say identical properties, relative to the
properties of an encapsulant in accordance with that described in the document WO
15 09138679, namely in particular relating to its transparency, its haze, its mechanical,
thermomechanical and fire retardant properties and its electrical insulation properties.
These tests proved to he positive.
The compositions according to the invention thus meet the criteria to be able to be
very advantageously used as hinder or encapsulant in solar modules.
20
Results of the tests carried out on the test specimens of the differerlt formulations:
Creep
(mm)
Adhesion
(NImm)
Test
AYI
(DHT2000h)
In the context of thc present invention, thc values desired with regard to the
different abovementioned tests arise as follows:
- the yellowness index, afler 2000 hours DIIT, has to be lcss than 3,
5 - the adhesion, for such a structure and application, has to be greater than
5 Nlmm,
- the creep has to be less than 3 millimeters.
On the assumption that the terpolymer is present in the composition according to
the invention at between 8% and 22%, the advantage obtained is a better result with
10 regard to the creep test carried out at a temperature of greater than 10O0C, typically
1 10°C or more.
CLAIMS
1. A photovoltaic module (20) cncapsulant (22) intended lo encase a
photovoltaic cell (lo), consisting of a composition not comprising any crosslinking
5 agent and comprising:
- an ethylenelalkyl acrylate copolymer, said copolymer representing between
70% and 96% ofthe weight of said composition;
- a silane, representing between 0.1% and 2% of the weight of said
composition;
10 characterized in that it additionally comprises an ethylenelacrylic
esterlmaleic anhydride or glycidyl methacrylate terpolymer, said terpolymer
representing from 2% to 29.9% of the weight of said composition.
2. The encapsulant (22) as claimed in claim 1, characterized in that the
15 said terpolymer represents between 8% and 22% of the weight of said
composition.
3. The encapsulant (22) as claimed in claim 1 or 2, characterized in that,
for the said copolymer, the content by weight of ethylene is between 60% and
20 85%, preferably between 70% and 84%, and the content by weight of alkyl
acrylate is between 15% and 40%, preferably between 16% and 30%.
4. The encapsulant (22) as claimed in any one of the preceding claims,
characterized in that the silane consists of an epoxysilane or an aminosilane.
5. The encapsulant (22) as claimed in claim 4, characterized in that the
silane consists of (3-glycidy1oxypropyl)triethoxysilane.
6. The encapsulant (22) as claimed in any one of the preceding claims,
30 characterized in that the said copolymer is present at between 75% and 95% by
weight of said composition.
WO 20151193581 PCTIF~015105d507
- 17 ;
7. The encapsulant (22) as claimed in any one of the preceding claims,
characterized in that the composition consists solely of the said copolymer, the said
terpolymer and the said silane
5 8. The encapsulanl (22) as claimed in any one of claims 1 to 6,
characterized in that the composition additionally comprises additives intended to
confer additional specific properties, in particular plasticizers, adhesion promoters,
W stabilizers and absorbers, antioxidants, flame retardants andor fillers.
10 9. The use of the encapsulant (22) as claimed in any one of the
preceding claims in a photovoltaic module (20).
10. A photovoltaic module (20) comprising a structure consisting of a
combination of at least one encapsulant (22) and a front sheet (24) or a back sheet
15 (26), characterized in that the encapsulant (22) is as claimed in any one of claims 1
to 8.