CA1114483A

CA1114483A - Laminated photovoltaic generator panel

Info

Publication number: CA1114483A
Application number: CA305,498A
Authority: CA
Inventors: Michel Tourneux
Original assignee: Philips Gloeilampenfabrieken NV
Current assignee: Koninklijke Philips NV
Priority date: 1977-06-24
Filing date: 1978-06-15
Publication date: 1981-12-15
Also published as: AU3737578A; FR2395609B1; GB2000371A; DE2826789A1; FR2395609A1; DE2826789C2; US4210462A; GB2000371B; JPS5410692A; AU519218B2

Abstract

Abstract:

A photovoltaic generator panel comprising a plurality of solar cells incorporated in a laminated assembly, each of the external faces of which is formed of a glass plate. The laminated assembly com-prises an inset plate formed of a transparent synthe-tic resin stable at elevated temperatures and provided with a recess for each solar cell. Optionally, an in-set film preferably formed of the same transparent synthetic resin can be positioned between the inset plate and one or both glass plates. Assembly of these several lamellar elements is effected by the use of a transparent adhesive polymerized at a temperature below 70° C.

Description

rJllF ~
BKS/YMB/G:~LI
4c41~ . 30-3-~197~
.

.
"Genera-tor panel having solar cells incorporated in a larrlinated assembly and method of manu~acturing said panel".

~he invention relates to a photovoltaic generator panel having a number of solar cells incorporated in a laminated assembly, in which each of the outer faces of said assembly cons.sts of a plate of vitreous material.
- 5 The invention also relates to a method of manufacturing such a panel.
It is known that the commercially available solar cells usually have a slice or layer of semiconductor material, for example silicon, in which a superficial and thin electric region is produced the conductivity type of which is opposite to that of the remainder of the material with which the sald superficial region fornls a photosensitive , junction. The solar cell uhich is provided with a suitable metal contact on each of its surfaces is characterized by its aptitude of converting a non-negligible fraction of the ; ~ energy which it receives in the form of exposure to sun L~gh-t, into electrical energy. As a rule, several solar cells are arranged in the form of a panel in such manner that when said ~ ~ .
cells are exposed simultaneously a certain sufficient power ~ ~20 is obtai}led corresponding to the needs to be satisfied in `~ the application in question.
~or te~rrestrial applications and taking iIltO ac-count the higll environmetral constraints to which the so~ar cells are exposed as~a result of the very d:ifferent weather influènces, it is usual that the encapsulation of the cells

2-in the form of generator panels ensures both a mechanical connection of the assembly of the cells and also a support for the required electrical connections as well as a desired protection against shocks, mechanical loads, in particular bending loads, and against corrosion which in particular influences the metallized contacts mainly under the influence of humidity.
Several constructions of solar generator panels are known for which it has been tried to ensure the most efficacious protection of the cells. In one of the known constructions the cells are arranged in a cup of polycarbonate which is filled with transparent silicone resin~ In a variation, the support of the rear face of the cells is formed by a plate of synthetic resin which is coated with glass fibres, analogous to those used for printed circuits, in which the cells are secured on said plate b~ soldering of the connections, the assembly being then covered with a layer of silicone resin, However, the generator panels obtained according to the produced struc-tures do not have a very good resistance to weather influ-ences. Furthermore, because the coefficient of thermal dissipation of said systems is not favourable for an efficacious cooling, the drawback occuxs in particular that the cells, during operation, reach a temperature which exceeds the ambient temperature which results in consider-able reduction of the degree of conversion of the system.
A known method suggested to form a generator ~ -_ 3 _ `'-~? ` .'',' ~ PHF 77-547 panel is based on the technique of the laminated plates of vitreous material. According to this method the solar cells are actually incorporated in a laminated assembly of which at least one of the two external elements ensures the rigidity of the assembly, assembling being carried out by means of a molten adhesive. ~lass plates or plates of a vitreous material are preferably used generally to form the external elements.
However, the method of assembling presents disadvantages. In fact, the rise in temperature of the panel with respect to the ambient air under the influence of a direct exposure to sunlight and according to a dis-position of the cells inside the panel which is more or less jointed may be estimated between 15 and 25C. The maximum temperature reached by the panel also depends on the highest temperature of the ambient air of the place in question. This may be comparatively high because the applications o~ solar energy in particular in tropical areas of the earth are of importance in which the highest temperatures may be 40 to 50C. It can be established that under the same severe operating conditions the thermo-plastic products which are used as adhesives to assemble the laminated assembly are softened to a considerable extend which is unfavourable for the good cohesion of the panel. Moreoever, due to the high temperatures prevailing in day-time followed by the coolings at night-time the fatigue of t:he assembly as a result of the dilatation . . ~ .
.,..

; . , ,. ., ' '~ ' :
:

P}IF 77-5l~7 30~3-19JX

constraints is increased which always occur inside the panel so that the properties and the per~ormances of this panel are deteriora.ted by working loose and infi.ltrations at the cir cumference thereo~.
One of -the obJects of the inventioll is to mitiga-te these disadvantages by an improv3rnent of the encapsulation o~ the cells while using the me-thod o~` the laminated. assemb:Ly with external faces of vitreous material. Accorcling to the invention, in particular an adhesive is used which remains insensitive to t:he temperature challges occurring iYI practical operating conditions and by means of wh.ich the laminated assembly can be assembled at a temperature which lies near ambient -temperature.
In fact, according to the invention~ a photo-voltaic generator panel having a n.umber of solar cells in-corporated in a laminated assembl~, in which said assembly is formed from lamellar elements by means of a transparent adhesive, those o~ the said elements ~orming each ex-ternal face being constituted by a plate o~ vitreous material, is characterized in that a first of the said lamellar elements is an inset plate the thickness of which is slightly larger -than that o~ the sa:id solar cells and whi.ch is provided with : recesses-in which the said ce1ls are accommodated, that the said inset plate consists o~ a syn.thetic resin the hardness o.~ ~hich is very stable at a rise in temperature up to at least r~OC!~ and that the said a~Ihesive is a material which is activated at a temperature helvw r~o C.
The generator panel a.ccording to -the ]..nvention PJII? 7 7 - 5 11 7 has the advantage -that its stability is very large under the heaviest climatological conditions.
The complete water-tightness of the plates of glass or of vitreous matrrial which are used as external faces o~ the assembly, which advantage is known per se~ but also the very good cohesion in the long run o~ the various - e]ements of the asscmbly and in particular o~ the circum-~erence thereof are used to advantage.
Said increased stability is due to the associat-ion, according to the invention, of synthetic resins the flexibili-ty of which is -thermally stable to -the rigid materials such as glass and semiconductor material ~on-stituting the cells of which the coefficients of expansion are very differen-t. In fact, said combination permits of freely absorbing t~e loads of a thermal origin wi-thout particularly large stresses occurring which are such that cracking or working loose occurs so tha-t the lateral pene-tration of moisture in the laminated assembly is favoured.
In a pre~erred embodiment of the invention the generator panel is further characterized in that -the said inset plate and at least one additional inset film which separates the said inset plate wi-th -the said cells from at least one o~ the said plates consist of a transparent ma-terial of the following list of materials: polyesters, 2~ metacrylates, epoxy resins, silicone rubber types~ epo~y aorylale resins and polyester acrylate resins.
A preferrcd embodiment o~ the ill~ention is in addition advalltageously characterizecl in that the adhesive used for assembling the laminated assembly is selected '`' .
~ . . .,.,, .. , , - . : ' ' .

Plll~ 77-SIl7 30-3-197~

'P'~

frorn the respective monoinerlc resins of the above-ment:ioned materials for the said inset pla-te and the said inset film, namely: polyesters~ metacrylates 5 transparent epoxide synthetic resins, silicone resins, photopolymeri~able epoxy acrylates and polyes-ter acrylate resins.
l`he invention relates tn addi-tion to a method o~ manufacturing a generator panel having the above-mentionecl characteris-tic features, which is charac-terized in that -two sub-assemblies o~ the said panels each of one of the said plates of vitreous material are ~`ormed, a first sub-assembly comprising a-t least -the said insc-t plate and the said mlmber of solar cells, the face to be fixed to -the second sub-assembly being coated wi-th a uniformly distribu-ted layer of the said adhesive, that the first and the second sub-assembly are introduced into a vacuum space, the faces to be combined being situated at some distance- from each other, that the sub-assemblies are subjected to a considerable negative pressure which is produced in the said vacuum space and that, while maintaining the said nega-tive pressure, the faces to ~0 be comblned are contacted with each other and held -together by means of a compression force which is exerted on the assembly while the said a~lesive hardens.
Tile said negative pressure produced in the said vacuum space advantageously results in a residual pressure of less than 1000 Pascal during the contacting of the said faces to be combined.
The method according to the lnvention has the ad~antaee that panels can be built in a simple manner in .. .
~ .. , . . . , . - . - , - , . . . .

P~ 77 - 5~
30~3- I ~7~.

which replocluceabl.e results oi`~hig}l qllal:ity are obtained.
Moreover, thi.s process can easily be used for series pro-duction.
A few embodiments of the invention are shown in the drawing and will be described in detail hereinaf`tex-.
Fig~ure 1 is a diagramma-tic partial sectioD.al view -through a generator panel. according to a f:i.rs-t embod.iment of the invenlion comprising an inset plate having recesses, . Figure 2 is a partial secti.onal view through a panel in accordance with a second embodiment comprising -,n addition an inset film, Figure 3 shows a partial sectional view of a third embodiment of a panel according to -the invention compr:ising two inset films in addition to the inset plate comprising recesses, Figure 4 shows in perspective the elements o~
- the panel during the assernbly thereof, alLd Figure 5 illustrates the method according to the invention in the phase of adheri.ng in a vacuum.
It is to be noted that in the vari.ous Figures certain dimensions are strongly exaggerQted so as to make the Figures clearerO
As shown in Figure 1, the Photovoltai.c genera-tor panel comprises a number of solar ce].ls in the form of discs of semiconduotor material, preferably silicon, of which one is deno-ted b~7 11 and is provi<.led wi.-th an electric conrLsotion 12 which connec-ts it to anot.her cell of the ~ssomb].y, and a con~-oti ~1 13 wh~oh le~d5 to the ~xter,or ~ ~.

- . . . .

~IF 77~547 30-3~1978 of the panel. l`he pancl comprises glass plates 14 and 15 f'orm-i.ng -the external ele~lents o~ a laminated assemb:Ly in whi,ch the cells, ~or example cell 11, are incorporated. ~ccording to the invention, -the laminatecl assembly is completed by an inset plate 16 which has recesses (such as 17) i.n which each o~ the cells (such as 11) is accommodated. The thlckness of the inset plate 16 is slightly larger than tha-t of -the cell 11 which is provided with its connec-tions~ so that the pla-tes 14 and 15 can in no case exert a direct pressure on the cell 11. According to the invention the material ~ormin~ the inset pla-te has a hardness which is subs-tantially s-table a-t tem~
peratures above and below the normal ambient ternperature, and in partic1llar up to 70~. In -this manner the cohesion o~ the laminated assembly in the panel according to -the inven-tion is obtained by means oP an adhesive 19 which occupies all the interrnediate spaces whi.ch are le~t ~ree i,nside the laminated assembly between the plates 14 and 15. In this manner the adhesive 19 ensures the mechanical connection between the in-set plate 16 and each of the plates 14 and 15 and also 'between ,, the cell 11 wi-th its connections 12 and,13 and -the said plates 14 and 150 In addition, due to its thermal conductivity, t.he adhesive 19 permits a *avourable dissipation o~ the heat produced by absorption of the radiation in the cell to the plates 14 ~mcl 15 and then to the ambient air. Finally~ the adhes.i,ve 19 is a mate,rial which is transparent to visible light and e~nsures, by its index oP re~raction approaching that oP glass, the necessary optical con-tinuity w:i-thin the laminated assembly up to the photosensiti.-ve Pace o~ the cell 11. In thi.s malLner~ e:~'iciency losses due to stray re~lections o.~ the light at the ~rte:r~Qces between the ~rario~s znaterlals .~

, .

Pll~ 7~
30-'3 1 9'78 ,Lq~

~`orming the laminated assernbly are avoided. According to the invention the adhesive 19 is a mate:ria]. which is poly-merized at ambient -temperature and at any rate at a tempera~
ture which does not exceed 70C. Thus, the elements formlng the panel and tke coe~fic:ients of expansion o~ which are di~ferent ~rom each o-ther can exert only strongly reduced loads both during the polymeriY.a-tion and subsequent].y under the practical opera-ting conditions which cannot produce ruptures o~ the adhesion in the assembly. ~dvantageously the adhesive 19 is a fle~ible material which preserves very stable mechani.cal properties and tempeIatures above and below ambient temperature and in particular betwee.n 0 and 700.
It is to be noted that the expression "glass plate" ~or the plates 14 and 15 which ~o:rm both the pro-- tection of the cclls and the rigid elernent of the lami.nated assembly has been used, but this expression comprises more generally the vitreous or vitrocrys-talli.ne transparent . materials which may or may no-t have been subjected to a particular thermal treatment.
However, as is known already, a gl.ass or a vitreous material is advan-tageously chosen which absorbs the solar radia-tions in the ultraviolet rangeS which radiations on the one hand are not i~ully converted by the 2~ ~lown solar cells and on th0 other hand may a-ttack cer-tain synthetic resins wllich may be used as a lamellar element for the ~ormatioII of the lamillated assembly.
Tha inset plate 1~ is advantageously formed by ~:'' ' :

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.
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PIII~ 7~-5ll7 30-3-lg~

a material which is ~lexible in a :Large -temperature range aro~nd the normal ambient temperature and in particular up -to 70~ and which does not soften excessively either.
The inset plate 16 advantageously consist~ in addit:ion o~
a transparent material such that the absorption of the light is limi-ted subs-tan-tially to the ~ield o~ solar cells so tha-t the heating o* the panel i5 reduced.
The inset pla-te 16 advantageously consis-tso~
- a material selected ~rom the ~ollowing materials: poly-esters, metacrylates, epoxide synthetic resins9 silicone rubber types, and epoxy acrylate and polyester acrylate resins.
As indicated, in a ~avourable embodiment of the invention the adhesive oonsists of rnonomeric material which corresponds to the polymerized body used ~or the inset plate 16 so that the adhesion between the componen-ts o~ the laminated assembly is op-timum. There~ore, o:~ the monomeric transparent materials are used: polyesters, metacrylates, epoxide synthetic resins, silicone resins, and photopolymerizable epoxy acrylate and polyester acrylate resins, respectively.
~igure 2 is a diagrammatic sectional view o~
another embodiment o~ the panel according to the invention.
According to this embodiment are used in the ~irs-t place 2~ constituents corresponding to those o~ ~ig. 1, namely:
a solar cell 21 o~ semiconductor material (a cell o~ an asselnbly o~ ce]..l.s not shown); the said cell 21 which is providcd with i-ts electrical connections 22 and 23 i8 --1 1-- ` , .. .. . . . .
' ' ' `: ' ' ' '.: ~ , . . .. ' ' '` `'' `

P~IF 77_5L17 30-3-19~8 arranged in the recess 27 of an inset plate 26 within a laminated assembly whose exterllal lamellar elements are formed by the glass plates 24 and 25.
The panel shown in F:ig. 2 ~urthermore comprises an inset film 28 which advantageously is formed by a synthetic resin -the hardness of which is stable at least up to 70C.
As shown in Fig. 2, the inset film 28 fully separates the inset plate 26 and -the cell 21 from the plate 24. By this measure the advantage is obtained that, while taking into account the ~ature of the material forming the inset film 28, the interior of the laminated assembly is given an additional flexibility opposing -the stresses which are dangerous for the cell 21 which in general is rather fragile. One of the principal faces of the cell 21 is the photosensitive face which comprises the superficial e~ectric region the conduotivity type of which is opposi-te to that of the remainder of the semioonductor material. This photo-sensitive face may be arranged on -the side of the cell ~hich is denoted in the Figure by 21b, that is to say on the side adjoining the inset film 28, and in this case a material is chosen for the formation of the inset ~ilm 28 which is transparent for the :light radiation which is used for the cell, that is a materia:L which in principle is transpar0nt to the vislble radiation. The photosensitive face of the cell may alternatively be arranged on the side which is deno-ted by 21c and in thls case the ma-terial forming tlle inset :[`ilm 28 i6 not necessari~ly transparent -12-- ~

- ' ~ .

PH~ 77-547 30 3~197~

to the visible light. In a p:referred embodiment of the panel shown in Fig. 2 the inset film 2S is formed by -the same material as the~nset plate 26.
The cell 21 and -the lamellar elements forming the laminated assembly shown in Fig. 2 are assernbled and held together by means of the adhesive 29 connecting -them together~ According to the invention~ the a~lesi.ve 29 consists of a transparent material of such a type that it is activated wi.th respect to i-ts adhering func-tion by poly-meri~ation at a temperature which is near normal ambient temperature, and at least below 70 C. Advantageously, the adhesive 29 is selected from the materials already described - - with reference to ~ig. 1.
Fig. 3 shows a third embodiment of the invention In this Figure which is a partial sectional view through a panel according to the invention~ the elements forming the laminated assembly and corresponding to those of Fig. 1 are referred to by the same reference numerals.
Centrally in the laminated assembly the inset plate 16 with the ceLls 11 accommodated in the recesses 17 is separated from the glass plates lL~ and 15 by the inset films 37 and 38~ respectively~ of a synthe-tic resin which is stable up to at least 70 Cg that one of ~the inset *ilms 37 and 38 which adjoi~is the pho-tosensitive surface of , .
the cell 11 being transparent. T~le assembly of the elements : :
of the laminated assembly is held in a coherent manner by means of an adhesive -whlch iæ divided in-to four layers~
namely the layer 39a: which connects the inset film 37 to :

' ~13-- ..

PII~ 77_51~7 30-3-197~

the plate 14; the layer 39b whicll connccts the ins~t Iilm 37 on one side with the inset plate 16 and on the other side with the cell 11; the layer 39c which connects the same elements by their facing ~aces to the inse-t f:ilm 38, and ~inally the layer 39dj which connects the said i.nset film 38 to the plate.s 15.
According to the invention, the adhesive of the layers 39a to 39d consists o~ a transparent material which is acti~ated at a temperature which lies near normal ambient temperature. In addi-tion, the said adhesive ad-vantageously is a body which is rather flexible af`ter tlle ac-tivation so that the eflects of the thermal eYpansion of the rigid elements of the laminated assembly can be absorbed without difficulties by the plastic elements.
In a preferred embodiment of the ~ariation described of the invention, th.e inset plate and the assembly of the inset film~s) ~hich may be used is manu~actured ~rom a material which is transparent to sunlightO More precisely, the inset plate 26 and the inset f~ n 28 of ~ig. 2 or the inset plate 16 and the inset films 37 and 38 o.f Fig. 3 are manufactured in the same panel and of the same transparent material. Thus, the panel does not ful].y absorb the solar radiation in -the ~ones which are not occupied by the cells. This measure is advantag~eous, in .
particular because it permits of red.ucing the rise in temperature ul1der the influence of the radiation ln the operating oond:i.tionsi. So i.t has been ~oulld -that the degree .
-. .

~ ' .

Pll1~ 77-5ll~
- 30-~-l97 L~

of conversion of the solar cclls is impro-ved.
Otherwise, in the examples of Figures 2 and 3 in ~hich several lamellar .inset elements are used, the selection and mutual compa-tibil:ity problems of the various materials, notably in relation with the adhesive used, are simpliri.ed by -the choice of the same composition of`
~he said elements.
The thickness oI -the elements f`orming the laminated assembly may be varied within w.ide limits without objections, as will be indicated~ and also in accordance with the type of application and the stresses which the panels should be capable of resl.sting. Thus, the thickness o~ the plates of glass or of vitreous material i.s typically chosen in a range of 2mm to 10mm in accordance with the size of the surface of the panels a.nd of` the mechani.cal rigidity envisaged for these panels~ In the case in wllich the solar cells have a thickness in the proximity o~
0.25 mm, as in the cells used by ~pplicants, the thickness of the inset plate with recesses, for e~ample 16 in Figures 1 and 3 or 26 in Fig. 2, is advantageously chosen to be slightly hig~her taking into account the complementary thiclcness represented by the metallic connection lugs t~h~ch are so:Ldered on each face of the cell. Said thickness is, ~or exarnple, in the order o~ magnitude of 0.3 to ~S mm.
`In the modified embodimen-ts of the inveMtion shown in ~igs. 2 and 3 one or two in~t films 28 (Fig. 2), 37 and 38 (F:i~r. 3) are incorporated in the laminated .assembly. 'l`he thicl~ness of such an inset f`ilm is suff`icient .

... . . .

Pl ~ 7 rj ) 1 7

3 () ~ 3 ~

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in a large range :~rom 0.05 mm to 1.5 mrn and in particular in the proximity o:~ 0.2 to o.~m.
A method w.ill now be d.escribed9 with ref`erence to ~ig. 4, which is particularly sultable f`or the manu:~acture of the photovoltaic ~enerator panels according to the inventi.on, the said method also f'orming part o~ the present inventi on .
First a ~ace of a f`irst glass pla-te 41 i5 coated with a -thin regular layer o:~ a liquid adheslve ~12.
The inset plate A3 with recesses 17 is -then fixed on the plate 4I by means of` the .layer of` acUlesive 42 f`rom whi.ch all air i.nclusions can be driven out easily by exer-ting a pressure by means of`, for example, a roller. ~pp:roximattely in the centre of` each recess, a certain quantity of` adhesive is deposited on the plate 41 which is added to the layer 42. This ope.ration is shown dia~rammatically in the Figu:re b~ the arrows 44. The complete netwo:rk of` cells 1~5 which are eonnected via their connectio~ls i.n an arrangement which corresponds to the recesses o:~ the inset plate 43 is d.eposi.ted in the said recesses comprising the above excess of`
adhesive while a new quantity of` adhesive is again deposi.ted approxima-tely in the cen.tre o~ each cell, which operation is shown diagrammatica~lly by -the arrows 46. The additional quantit~T o:f adhesive which is t:hus dist;rib~ted over all the eeLls is establishecl accorcling to -the invention in such manner that the recesscs of the irl~ plate 1~3 are -~i.]led clltirely~ wi.tllQut: interrup-tions, but even witll a very smal:L
excessS by the cells and the a.dhesi~e.

~16-. , ... - . : :

P~L? 77~nr)~l7 - 3~3~'l~7~

~4~

Tlle first subassembly obtainec~ in this sta~e o:~
-the me-thod is axranged :in the rest position (in t:h.e hori~
zontal pOSiti OIl) whil.e a ~ace of the second glass plate 48 is coated with a thin laye:r o~ adhesive 49. An i~set film 50 is -then provided by pressure on tlle coated face of the plate 48 a~-ter which ~inally the ou-ter ~ace of the inset film 50 is coated with a layer of adhesive ~1. In th:is manner a second sub-assembly which is complementary to the flr.,-t ls obtalned which is destlned to be provlded on the f':irst sub assembly by pressure in such manne:r that the f'ace coated with the layer o~ adhesive 51 is opposlte to the lletwork o~
cells 4~ and the lnset plate 43.
. Optimum results are achleved when the process o~ comblning the two sub-assemblies is carried out in a vacuum so that no discontinuitles are present ln the layer o~ adhesive or no air lnclusions ln the laminated assembly~
~or that purpose~ accordlng to the lnvention, the two sub-assemblles are arranged wlthin a chamber in a horlzon-tal posi-tion parallel to each other ln such manner that the sur~ace to be comblned do not touch each other but are situated opposite to each other~ said chamber being connected :~ - with pump:ing means and ~urther moving means are provided w~i.ch can be controlled ~rom the exterlor ~hile the chamber is evacua-ted. The chamber ,is -then evacuated and when the residual pressure has dropped below 1000 Pascal:, th.e two oppo.~tely located parts are combi,ned; these parts are then held toget:~ar by exerti.n~, ~or e~.ample, a l,oad. 'I`he ~acuum ln the charnber may then. be rellloved and the panel , . -17 : . .

P~ 7 51l7 30-3--19~l8 in question may be removed from the chamber ar)d is still held together under the action of the load. Thel1 there is waited until tlle adhesive has ac-tiva-ted by polin1er:i%ation in such mann~r that the pressure exerted on the panel is removed.
S In a modi~ied embodiment of the method accord:ing to -the :in-vention the panel combined under the influence of pressure is left irl the vacuum space during -i;he period of time required for the activation of the adhesive.
A clevice for carrying~ out the method of assem-bling the panel in a vacuun~ is shown ln Fig. 5 as a non-limiting example. It comprises a chamber 60 provided ~ith an evacuation tube 61 which leads to a vacuum pump not shown and an air inlet 610 having a cock 611. 1`1le chamber 60 comprises in addition displacement means ~hich can be controlled from the exterior and are formed by pins 62 and 63 ~.~hich slide in a water-tight manner through -the wall of the chamber and are connected together by means of a brace 64 -the height of which can be varied by means of the adjusting screw 65~ and the frame 66, reproducing the movement of the brace 64 inside the charnber 60. The frame 66 has supporting plates 67 and 68 which ~eep the sub-assembly 70 spaced from the sub-assembly 71 until thc vacuum in the chamber is produced. Pressure can be e~erted Oll the assem'bly in the final stage of the me-thod by a load 72. FiIIally~ a support 73 serves to present the sub-a,ssembly 71 parallel to and at a small d:istance from the sub-assembly 70 in the cles:ired position.
The sub-assembly 7'1 ~7-hlch 'bears on the S1lpport - . . , . :

1'll:l~`'~7~ 7 ~`` 30-3-19~78 73 is the sub-assembly which compri.ses the inset plate with recesses, t;he ne-twork of cel:l.s and the excess of adhesive which are mentiolled above (these détails are not shown in Figur~ 5).
When during the assembly the sub-assembly 70 is contacted with the sub-assem'bly 7'1, the excesses of adhesive distribute by -the pressure exerted on the assembly over the whole volume of the recesses and fully surround the cells~
The small excess of adhesive automatically f'ills the interl-mediate spaces of the adhesive layers which during the operations are not coa-ted with adhesive. This p:rocess can be further facili-tated when -the sub-assembly 70 is sligrhtly c~rved under the action of the load 72 provided cen-trally ' and of the supporting plates 67 alld 68 retaining -the cir-cumference.
. The s-tructure o~ the panel which is obtained . .
during the process as has been described so far, corresponds to the'device shown in Figure 2. This method can be modi.-fied in a simple manner so that a structure is ob-tained which 2~ - is equivalent to -that of Fig. 1 in that the inse-t film 50 and its layer of adhesive 51 (Fig. 4) are omitted so tha-t the second sub-assembly which is to be provided on the first sub-assembly wi.th the cells then comprises only the glass pla-te ~8 which is coated wlth i.ts layer of' adhasive 490 On the contrary, the structure shown in Flg. 3 is obta:ined in that between the pla-te 11 and the inset plate 43 an additiol-lal inse-t :~ilm (not shown) is provided w'h:ich is arranged on -t.he said p:late af'ter ~rhic:h it is .

~ .

- ~ - ' . ~ I .
: ................................... .

30~3-- 1 978 coated wi.th adhesive in the manner described for the in~et film 50 and the glass plate 48.
By the method according to the invention panels can be assembled the rigidity and opti.cal properties o~
which are very favourab:Le. The panels obtalned rnay be giv~n a circumferential ring for protection againsl, shocks, which ring is advantageollsly flanged and can exert a certain pressure on the external faces along the circumfereIlce of the glass plates.
It is to be noted that details regarding the structures described as ~.~ell as the methods of mamlfacturiJ~g ma.y be va:r.ied within the scope of this invention.

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1.
--2C~~ I

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS

1. A photovoltaic generator panel which comprises a plurality of lamellar elements, the two external lamellar elements being formed of a vitreous material, at least one of said vitreous material lamellar elements being transparent, an inner lamellar element provided with a plurality of openings, said inner lamellar element being formed of a synthetic resin having a softening temperature above 70°C, a solar cell positioned in each such opening, the thickness of the inner lamellar element being slightly greater than that of the solar cells and a transparent adhesive bonding said lamellar elements and said solar cells together, said adhesive being a synthetic resin formed from a monomer polymerized at a temperature below 70°C.

2. A generator panel as claimed in Claim 1, characterized in that a second of the said lamellar elements forming the said laminated assembly is a first inset film of a synthetic resin which is stable up to at least 70°C
and which fully separates the said inset plate and the said cells from the first of the said plates.

3. A generator panel as claimed in Claim 2, characterized in that a second inset film of a synthetic resin which is stable up to at least 70°C also separates the said inset plate and the said cells from the second of the said plates and that at least that one of the said films which adjoins the photosensitive surface of the said cells is transparent.

4. A generator panel as claimed in Claim 2, characterized in that at least one of the said inset films and the said inset plate are manufactured from the same transparent material.

5. A generator panel as claimed in Claim 4, characterized in that the said material is selected from the following list: polyesters, metacrylates, epoxide synthetic resins, silicone rubber types, as well as epoxy acrylate and polyester acrylate resins.

6. A generator panel as claimed in Claim 1, 2 or 3, characterized in that the said adhesive is sel-ected from the following list of the monomeric resins:
polyesters, metacrylates, transparent epoxide synthetic resins, silicone resins, as well as photopolymerizable epoxy acrylate and polyester acrylate resins.

7. A method of manufacturing a generator panel as claimed in Claim 1 in which for obtaining the assembly of the said panel in a suitable sequence the said ele-ments of the said laminated assembly are laid on each other and said elements are connected together by means of the said adhesive, characterized in that two sub-assemblies of the said panel are formed each from one of the said plates of vitreous material in which the first sub-assembly comprises at least the said inset plate and the said number of solar cells and the face of the second sub-assembly to be fixed is coated with a uniformly dis-tributed layer of the said adhesive; that the first and the second sub-assembly are introduced into a vacuum space in which the faces to be assembled are situated at some distance from each other; that the sub-assemblies are subjected to a considerable negative pressure which is produced in the said vacuum space and that, while maintaining the said negative pressure, the faces to be assembled are contacted with each other and are held together by means of a compression force which is exerted on the assembly, while the said adhesive hardens.

8. A method as claimed in Claim 7, character-ized in that the said negative pressure produced in the said vacuum space leads to a residual pressure under 1000 Pascal during the contacting of the said faces to be assembled.

9. A method as claimed in Claim 7 or 8, charac-terized in that during the time necessary for hardening the said adhesive, the assembly is held under the influ-ence of the said negative pressure in the said vacuum space.

10. A method as claimed in Claim 7 or 8, charac-terized in that after contacting the said faces of the said sub-assemblies and immediately after exerting the said compression force the said space is brought at atmos-pheric pressure after which the said assembly is removed from the said space while the said compression force is still exerted on the assembly during hardening the said adhesive.