Front-face substrate for a solar module

Abstract

The invention relates to a front-face substrate for a solar module, in particular for mobile applications, for example mobile devices, means of transportation, or manned or unmanned flying objects, wherein the front-face substrate has a weight per unit area of under 500 g / m² and comprises a material which has a transmission curve T(λ) for a reference thickness of 100 µm, said transmission curve forming a transition from a lower transmission Tlow to an upper transmission Tup and having a transitional transmission Ttr therebetween of 50% in a wavelength range of 302 nm to 322 nm.

Description

[0001] Front substrate for a solar module

[0002] The invention relates to a front substrate for a solar module, in particular for mobile applications.

[0003] Solar modules are often constructed with a rear element, which can also be called a back panel, a front element, which can also be called a cover or front substrate, and the solar cell itself, which is arranged between the back panel and the cover to protect it from unwanted influences and to increase stability.

[0004] The individual components of the solar module can be optimized for the desired application. The front substrate can be particularly important in this case, and it must be designed to be transparent to the relevant radiation.

[0005] The present invention is based on the object of providing a front-side substrate which is optimized for various mobile applications and is therefore versatile in use, in particular for mobile devices, means of transport, transportation or manned or unmanned aerial vehicles, while at the same time being as inexpensive to produce as possible and also allowing the most cost-effective construction of the solar module or a reduction in the costs of other components of the solar module. One aspect of the object is also a high solarization resistance. To achieve the object, a front-side substrate for a solar module is disclosed which has a basis weight of less than 500 g / m 2 and which comprises a material which, at a reference thickness of 100pm, has a transmission curve T(X) which shows a transition from a lower transmission T Jow to an upper transmission T upand an intermediate transition transmission T tr = 50% in a wavelength range from 302 nm to 322 nm.

[0006] The front-side substrate is particularly intended for mobile applications, such as mobile devices, means of transport, or manned or unmanned aerial vehicles.

[0007] With a basis weight of less than 500 g / m 2 The front-side substrate can contribute to a weight reduction of the solar module, which can be advantageous for some mobile applications. A weight-reduced solar module can be particularly advantageous for manned or unmanned aircraft, e.g., passenger aircraft, gliders, drones, possibly also rockets, satellites, etc., and also for vehicles or mobile devices.

[0008] In some of these applications, such as drones or mobile devices, battery weight can also be saved if power can be supplied partly by a solar module.

[0009] In some applications, especially in aircraft or flying objects, a high level of UV radiation or even particle radiation can also prevail. Since the front substrate has a transmission curve T(X) at a reference thickness of 100 pm, which represents a transition from a lower transmission T Jow to an upper transmission T up and an intermediate transition transmission T tr= 50% in a wavelength range from 302 nm to 322 nm, a protective effect for the solar cell can be achieved, particularly in the short-wave range. In particular, the transmission curve T(X) can also ensure a protective effect for applications in aircraft or flying objects where high levels of UV radiation can prevail. Overall, this enables versatile applicability for a wide variety of mobile applications.

[0010] Because the transmission curve T(X) enables a targeted protection effect against short-wave radiation, additional filters as components of the solar module can sometimes be eliminated, thus in turn achieving a reduction in weight and costs.

[0011] If necessary, more cost-effective adhesive materials can also be used in solar modules that include an adhesive layer for connecting the front substrate to the solar cell or for laminating the solar cell.

[0012] It is worth mentioning that the combination of the mentioned basis weight and the transition transmission, which defines a relatively high UV edge, interact in such a way that both savings in the material of other components, e.g. the adhesive of the solar module, are possible and its overall weight can be reduced.

[0013] In principle, the above-mentioned transmission curve T(X) refers to a reference thickness of 100 μm. Conversion to a different thickness is possible by performing a thickness measurement, a transmission measurement, and a dispersion measurement (i.e., determining the wavelength-dependent refractive index) for the glass of the different thickness. From this, the pure transmission and the absorption coefficient are calculated. Subsequently, the pure transmission for the reference thickness of 10 μm and, taking reflection losses into account, the transmission for the reference thickness of 10 μm can be calculated.

[0014] In a further development of the invention, it can be provided that the front substrate has a basis weight of less than 400 g / m 2 , preferably less than 300 g / m 2 , particularly preferably less than 250 g / m 2 , more preferably less than 200 g / m 2A basis weight of less than 275 g / m 2 may also be preferred .

[0015] Furthermore, in a further development it can be provided that the transition transmission T tr = 50% lies in a wavelength range from 304 nm to 318 nm, preferably in a wavelength range from 306 nm to 314 nm, preferably in a wavelength range from 308 nm to 312 nm. The front-side substrate can in particular have a thickness which is less than 150 pm, preferably less than 100 pm, particularly preferably less than 80 pm, even more preferably less than 60 pm, even more preferably less than 40 pm.

[0016] The front side substrate can thus be designed in particular as ultra-thin glass (UTG).

[0017] Preferably, it can be provided that the transmission curve T(X) falls below a value of T tr = 10% decreases with a

[0018] Wavelength in a wavelength range of 288 nm to 312 nm, preferably in a wavelength range of 294 nm to 306 nm, particularly preferably in a wavelength range of 298 to 302 nm.

[0019] Furthermore, it can preferably be provided that the transmission curve T(X) has a value of T tr = 90% increases at a wavelength in a wavelength range of 322 nm to 400 nm, preferably in a wavelength range of 330 nm to 380 nm, particularly preferably in a wavelength range of 335 to 360 nm.

[0020] In principle, this can be used to achieve the highest possible transmission in the operating range of typical solar cells. For example, the transmission for VIS and NIR can be greater than or equal to 91%. High transmission for VIS and NIR is particularly advantageous for mobile applications at higher altitudes, e.g., in aircraft or flying objects. This is particularly important in conjunction with the aforementioned transition transmission, which enables a relatively high UV edge for shorter-wave radiation.

[0021] In a further development, the lower transmission T Jow be less than 5%, preferably less than 2.5%, particularly preferably less than 1%.

[0022] Alternatively or additionally, the upper transmission T up be greater than 85%, preferably greater than 87.5%, particularly preferably greater than 90%.

[0023] In one embodiment, it can be provided that the lower transmission Tj ow at a wavelength of at least 250nm, preferably at a wavelength of at least 275nm, particularly preferably at a wavelength of at least 285nm, even more preferably at a wavelength of at least 290nm.

[0024] Alternatively or additionally, in one embodiment it can be provided that the upper transmission up at a wavelength of at most 375nm , preferably at a wavelength of at most 350nm , particularly preferably at a wavelength of at most 340nm , even more preferably at at most 335nm .

[0025] For example, the transmission curve may have a gradient of 2.8 percentage points / nm at least at one point, in particular at a point between the lower transmission Tj ow and the upper transmission Tup , preferably between a transmission of 10% and 80%. By selecting a suitable solarization resistance, the glass of a front-side substrate can remain as transmission-stable as possible under UV irradiation, so that the transmission curve, in particular the transition transmission, shifts as little as possible.

[0026] For example, it can be provided that the transmission curve, in particular the transition transmission T tr = 50%, after irradiation for 7 hours with light in the wavelength range from 250 nm to 600 nm, in particular with a spectrum according to Fig. 5, has a shift of less than 5.0 nm, preferably has a shift of less than 3.0 nm, particularly preferably has a shift of less than 1.0 nm, even more preferably has a shift of less than 0.5 nm

[0027] Alternatively or additionally, according to a further definition, it can be provided that the transmission curve, in particular the transition transmission T tr = 50%, after irradiation for 100 hours with UV-A light at 210 W / m 2 , UV-B light with 170 W / m 2 and UV-C light with 250 W / m 2 , in particular with a spectrum according to Fig . 6 , has a shift of less than 5 .0 nm , preferably has a shift of less than 3 .0 nm , particularly preferably has a shift of less than 1 .0 nm , even more preferably has a shift of less than 0 .5 nm

[0028] In one embodiment, the material of the front-side substrate may comprise a glass, in particular a borosilicate glass, which has a glass composition that contains no Li2O or contains Li2O in a proportion of less than 50 ppm, preferably less than 10 ppm, particularly preferably less than 5 ppm, and even more preferably less than 1 ppm. Li2O is a component in glass that can diffuse relatively easily and thus damage semiconductors such as solar cells.

[0029] Furthermore, it can be provided that the glass composition contains no CaO or contains CaO in a proportion of less than 50 ppm, preferably less than 10 ppm, particularly preferably less than 5 ppm, and even more preferably less than 1 ppm. This can be desirable or advantageous, particularly with regard to the elastic modulus or flexibility of the glass.

[0030] Furthermore, it can be provided that the glass composition contains no MgO or contains MgO in a proportion of less than 50 ppm, preferably less than 10 ppm, particularly preferably less than 5 ppm, and even more preferably less than 1 ppm. This can be desirable or advantageous, particularly with regard to the elastic modulus or flexibility of the glass.

[0031] Furthermore, it can be provided that the glass composition contains no BaO or contains BaO in a proportion of less than 50 ppm, preferably less than 1 ppm, particularly preferably less than 5 ppm, even more preferably less than 1 ppm. Furthermore, it can be provided that the glass composition contains no SrO or contains SrO in a proportion of less than 50 ppm, preferably less than 1 ppm, particularly preferably less than 5 ppm, even more preferably less than 1 ppm.

[0032] Furthermore, it can be provided that the glass composition contains no antimony (Sb) or contains antimony (Sb) in a proportion of less than 50 ppm, preferably less than 10 ppm, particularly preferably less than 5 ppm, and even more preferably less than 1 ppm. This can be desirable or advantageous, particularly with regard to toxicity or occupational safety. Furthermore, polyvalent ions such as Sb2Oa can sometimes have a negative effect on solarization resistance, depending on the glass matrix.

[0033] Furthermore, the glass composition may contain no arsenic (As) or antimony (As) in a proportion of less than 50 ppm, preferably less than 10 ppm, particularly preferably less than 5 ppm, and even more preferably less than 1 ppm. This may be desirable or advantageous, particularly with regard to toxicity or occupational safety. Furthermore, polyvalent ions such as AS2O3 can sometimes have a negative effect on solarization resistance, depending on the glass matrix.

[0034] In one embodiment, the material of the front-side substrate may comprise a glass, in particular a borosilicate glass, which has a glass composition that contains no cerium oxide or contains cerium oxide in a proportion of less than 500 ppm. This may be desirable or advantageous, particularly with regard to the position of the transition transmission and / or the efficiency in the VIS-NIR transmission spectrum. In particular, a higher transmission for blue light may be achievable.

[0035] Depending on the application, cerium oxide may be deliberately omitted to further reduce costs, although cerium oxide can also be advantageous in terms of solarization resistance. This can be a particularly advantageous compromise for mobile applications, especially for temporary use.

[0036] Cerium oxide is an element that can both counteract solarization of the glass and reduce blue light transmission. Surprisingly, it has been shown that sufficient solarization stability against UV radiation can also be achieved with glass that contains no cerium oxide or contains cerium oxide in a concentration of less than 500 ppm.

[0037] In one embodiment, it can be provided that the material of the front-side substrate comprises a glass which has a glass composition which contains TiO2 in a proportion of 0.5 to 10 percent by weight, preferably 2 to 8 percent by weight, particularly preferably 3 to 5 percent by weight.

[0038] Furthermore, it can be provided that the glass composition

[0039] A12O3 in a proportion of 0 to 15 percent by weight, preferably 3.5 to 15 percent by weight, particularly preferably 3.5 to 4.5 percent by weight.

[0040] Furthermore, it can be provided that the glass composition contains SiO2 in a proportion of 30 to 80 percent by weight, preferably 50 to 75 percent by weight, particularly preferably 60 to 70 percent by weight.

[0041] Furthermore, it can be provided that the glass composition contains B2O3 in a proportion of 3 to 20 percent by weight, preferably 5.5 to 9.5 percent by weight, particularly preferably 7.5 to 8.8 percent by weight.

[0042] The material of the front substrate may have a density less than 3.25g / cm 3 , preferably less than 3g / cm 3 , particularly preferably less than 2.75g / cm 3 .

[0043] In one embodiment, the front-side substrate may have a modulus of elasticity higher than 68 GPa, preferably higher than 70 GPa, more preferably higher than 72 GPa and / or a modulus of elasticity lower than 78 GPa, preferably lower than 76 GPa, more preferably lower than 74 GPa.

[0044] The material of the front substrate may have a thermal expansion coefficient in a temperature range of 20°C to 300°C which is greater than 4xlO" 6 K -1 , preferably larger than 5x10" 6 K -1 , particularly preferably larger than 6xlO" 6 K -1 , preferably larger than 7xlO" 6 K -1The thermal expansion coefficient can thus, for example, be advantageously adapted to that of a solar module, in particular to that of an adhesive layer, a solar cell, and / or a backing element, or vice versa. For example, cost savings for a backing element can be considered through the use of cheaper materials.

[0045] The front-side substrate can have a dimension greater than 35 cm, preferably greater than 45 cm, particularly preferably greater than 60 cm, and / or a second, e.g., orthogonal, dimension greater than 65 cm, preferably greater than 75 cm, particularly preferably greater than 90 cm. For example, a front-side substrate with dimensions of 55 x 80 cm is possible.

[0046] One advantage of the relatively large dimensions mentioned above is that the solar cells in a solar module can be covered with as few front-side substrates as possible, thus reducing handling and bonding costs. These relatively large dimensions can only be realized technically as standard and cost-effectively in conjunction with the aforementioned glass thicknesses, e.g., UTG.

[0047] The invention further relates to a front side unit for a solar module, in particular for mobile applications, for example mobile devices, means of transport, means of transportation or manned or unmanned flying objects, comprising a front side substrate as described above and an adhesive layer which is applied flatly to the

[0048] The invention further relates to a solar module, in particular for mobile applications, for example mobile devices, means of transport, means of transportation, or manned or unmanned aerial vehicles, comprising a front-side substrate as described above, preferably a rear-side element, which is designed in particular as a module frame, a solar cell, which is preferably arranged between the rear-side element and the front-side substrate, and an adhesive layer which connects the front-side substrate to the solar cell.

[0049] An adhesive layer may comprise at least one of the following materials: butyl polymer, EVA, PVB, SMP (silyl-modified polymer), transparent silicone.

[0050] Furthermore, the invention relates to the use of a front-side substrate as described above or a front-side unit as described above for a solar module, in particular for mobile applications, for example mobile devices, means of transport, means of transportation or manned or unmanned flying objects.

[0051] Finally, the invention also relates to the use of a solar module as described above for mobile applications, for example mobile devices, means of transport, means of transportation or manned or unmanned aerial vehicles.

[0052] The invention is described in more detail below with reference to the figures, in which:

[0053] Fig. 1: a schematic representation in plan view of a

[0054] Front side substrate s , Fig . 2 : a schematic representation in sectional view of a front side unit with a front side substrate and an adhesive layer ,

[0055] Fig. 3 : a schematic representation in sectional view of a solar module,

[0056] Fig. 4 : a graph of the transmission curve of a front substrate with a thickness of 100 pm before and after solarization irradiation with a radiator with an energy distribution according to Fig. 6 ,

[0057] Fig . 5 : a graph of a relative spectral

[0058] Energy distribution of a radiator for investigating solarization resistance,

[0059] Fig . 6 : a graph of a relative spectral

[0060] Energy distribution of another radiator for investigating solarization resistance.

[0061] Fig. 1-3 show a front-side substrate 100 (Fig. 1), a front-side unit 10 with a front-side substrate 100 and an adhesive layer 110 applied flatly on one side of the front-side substrate 100 (Fig. 2), as well as a solar module 1 with a solar cell 200 which is arranged between a front-side substrate 100 (or a front-side unit 10) and a rear-side element 300, wherein the front-side unit 100 is bonded flatly to a surface of the solar cell 200 by means of the adhesive layer 110 (Fig. 3). The front-side substrate has a basis weight of less than 500 g / m 2 on , for example a basis weight of 251 g / m 2 and a thickness of 100µm. Furthermore, the front-side substrate has, for example, a glass composition containing the following proportions in weight percent:

[0062] Fig. 4 shows transmission curves of such an exemplary front-side substrate with a thickness of 100 pm before and after a solarization test in which the substrate was exposed to UV-A light with 210 W / m 2 , UV-B light with 170 W / m 2 and UV-C light with 250 W / m 2 was irradiated. The irradiation spectrum is shown in Fig. 6. It can be seen that the transmission curve and the transition transmission T tr = 50% have a displacement of less than Inm .

[0063] Another exemplary glass composition comprises the following proportions in weight percent, with iron contamination in the range of <50ppm:

[0064] For the two glass compositions mentioned, solarization tests were also carried out for a front-side substrate with a thickness of 1 mm, alternatively using irradiation with a spectrum according to Fig. 5 for 7 hours. Here, too, it was shown that the transmission curve and the transition transmission T tr = 50% have a displacement of less than Inm. Another exemplary glass composition includes the following proportions in weight percent:

[0065] Another example of a glass composition includes the following proportions in weight percent: In particular, a glass composition can be provided which comprises the following proportions in percent by weight:

[0066] In particular, a glass composition as described above, but also a glass composition independent of the other components mentioned above, can comprise a proportion of titanium oxide which is in the range of 0-6, in particular in the range of 3-5, e.g. 4. Furthermore, the glass composition can, alternatively or in addition to such a proportion or a proportion of titanium oxide mentioned in the table(s), comprise a component which preferably acts as a UV absorber. For example, a proportion of one or more of the following components which is effective with regard to UV absorption is considered: cerium (e.g. in the form of CeO3), antimony (e.g. in the form of Sb3O3), whereby an antimony content should preferably not exceed 1% by weight, tin (e.g. in the form of SnO3), niobium (e.g. in the form of Nb3O3), iron (in the form of Fe3O3), in particular with a correspondingly adjusted Fe 2+ / Fe 3+-Redox ratio. Another exemplary glass composition includes the following proportions in weight percent:

[0067] Particularly with the exemplary glasses without cerium oxide, the raw glass costs can be kept low, so that a front-side substrate with the mentioned properties can be produced cost-effectively. In conjunction with a basis weight of less than 500 g / m 2 , e.g. under 300 g / m 2, thus both a reduction in the weight and the cost of a solar module can be achieved and, due to the transition transmission, a suitable protective effect for components of the solar module, such as an adhesive layer, can be achieved even under conditions of high UV radiation, which in turn means the use of more cost-effective adhesive layers, resulting in a cost-saving potential in several places and a particularly suitable application for mobile applications such as mobile devices, means of transport, means of transport or manned or unmanned aircraft.

Claims

Patent claims 1. Front surface substrate for a solar module, especially for mobile applications, for example mobile devices, means of transport, transport vehicles or manned or unmanned flying objects, wherein the front surface substrate has an areal weight of less than 500 g / m² 2 exhibits, and wherein the front substrate comprises a material which, at a reference thickness of 100 pm, exhibits a transmission curve T(X) which transitions from a lower transmission T Jow to an upper transmission T up forms and an intermediate transition transmission T tr = 50% in a wavelength range from 302 nm to 322 nm .

2. Front surface substrate according to the preceding claim, wherein the front surface substrate has an areal weight of less than 400 g / m² 2 exhibits, preferably of less than 300 g / m³ 2 exhibits, particularly preferably, less than 250 g / m³ 2exhibits, even more preferably, less than 275 g / m² 2 exhibits, even more preferably, less than 200 g / m² 2 exhibits , and / or wherein the transition transmission T tr = 50% lies in a wavelength range of 304 nm to 318 nm, preferably in a wavelength range of 306 nm to 314 nm, preferably in a wavelength range of 308 nm to 312 nm.

3. Front surface substrate according to one of the above Claims, wherein the front surface substrate has a thickness exhibits a thickness of less than 150pm, preferably less than 100pm, particularly preferably less than 80pm, more preferably less than 60pm, and more preferably less than 40pm.

4. Front surface substrate according to one of the preceding claims, wherein the transmission curve T(X) is below a value of T tr= 10% decreases at a wavelength in a wavelength range of 288 nm to 312 nm, preferably in a wavelength range of 294 nm to 306 nm, particularly preferably in a wavelength range of 298 to 302 nm, and / or wherein the transmission curve T(X) over a value of T tr = 90% increases at a wavelength in a wavelength range of 322 nm to 400 nm, preferably in a wavelength range of 330 nm to 380 nm, particularly preferably in a wavelength range of 335 to 360 nm .

5. Front surface substrate according to one of the preceding claims, wherein the lower transmission T Jow is less than 5%, preferably less than 2.5%, particularly preferably less than 1%, and / or wherein the upper transmission T up greater than 85%, preferably greater than 87.5%, particularly preferably greater than 90%.

6. Front surface substrate according to one of the preceding claims, wherein the lower transmission TJow at a wavelength of at least 250 nm is present, preferably wavelength of at least 275 nm, particularly preferably wavelength of at least 285 nm, more preferably wavelength of at least 290 nm and / or wherein the upper transmission T up at a wavelength of at most 375 nm, preferably at a wavelength of at most 350 nm, particularly preferably at a wavelength of at most 340 nm, and more preferably at at most 335 nm. Front-end substrate according to one of the preceding claims, wherein the transmission curve has a slope of 2.8 percentage points / nm at at least one point, in particular at a point between the lower transmission Tj ow and the upper transmission T up, preferably between a transmission of 10% and 80%. Front surface substrate according to one of the preceding claims, wherein the transmission curve, in particular the transition transmission T tr = 50%, after irradiation for 7 hours with light in the wavelength range of 250 nm to 600 nm, in particular with a spectrum according to Fig. 5, exhibits a shift of less than 5.0 nm, preferably a shift of less than 3.0 nm, particularly preferably a shift of less than 1.0 nm, again preferably exhibits a shift of less than 0.5 nm and / or wherein the transmission curve, in particular the transition transmission T tr = 50%, after irradiation for 100 hours with UV-A light at 210 W / m² 2 UV-B light with 170 W / m² 2 as well as UV-C light with 250 W / m² 2, in particular with a spectrum according to Fig. 6, has a shift of less than 5.0 nm, preferably has a shift of less than 3.0 nm, particularly preferably has a shift of less than 1.0 nm, and more preferably has a shift of less than 0.5 nm.Front surface substrate according to one of the preceding claims, wherein the material of the front surface substrate comprises a glass, in particular a borosilicate glass, which has a glass composition which does not contain Li2O or contains Li2O in a proportion of less than 50 ppm, preferably less than 1 ppm, particularly preferably less than 5 ppm, more preferably less than 1 ppm and / or wherein the glass composition does not contain CaO or contains CaO in a proportion of less than 50 ppm, preferably less than 1 ppm, particularly preferably less than 5 ppm, more preferably less than 1 ppm and / or wherein the glass composition does not contain MgO or contains MgO in a proportion of less than 50 ppm, preferably less than 1 ppm, more preferably less than 5 ppm. more preferably containing less than 1 ppm and / or wherein the glass composition does not contain BaO or contains BaO in a proportion of less than 50 ppm, preferably less than 1 ppm, particularly preferably less than 5 ppm, more preferably less than 1 ppm and / or wherein the glass composition does not contain SrO or contains SrO in a proportion of less than 50 ppm, preferably less than 1 ppm, particularly preferably less than 5 ppm, more preferably less than 1 ppm and / or wherein the glass composition does not contain antimony (Sb) or contains antimony (Sb) in a proportion of less than 50 ppm, preferably less than 1 ppm, particularly preferably less than 5 ppm, more preferably less than 1 ppm and / or wherein the glass composition does not contain arsenic (As) or contains arsenic (As) in a proportion of less than 50 ppm,preferably containing less than 1 ppm, particularly preferably containing less than 5 ppm, more preferably containing less than 1 ppm. Front-end substrate according to any one of the preceding claims, wherein the material of the front-end substrate is a, Glass includes, in particular, a borosilicate glass which has a glass composition that does not contain cerium oxide or contains cerium oxide with a Contains a proportion of less than 500 ppm. Front-end substrate according to one of the preceding claims, wherein the material of the front-end substrate comprises a glass having a glass composition containing TiCt in a proportion of 0.5 to 10 wt. percent, preferably 2 to 8 wt. percent, particularly preferably 3 to 5 wt. percent, and / or wherein the glass composition contains Al₂O₃ in a proportion of 0 to 15 wt. percent, preferably 3.5 to 15 wt. percent, particularly preferably 3.5 to 4.5 wt. percent, and / or wherein the glass composition contains SiCt in a A glass composition comprising 30 to 80% by weight, preferably 50 to 75% by weight, particularly preferably 60 to 70% by weight, and / or wherein the glass composition contains B₂O₃ in a proportion of 3 to 20% by weight, preferably 5.5 to 9.5% by weight, particularly preferably 7.5 to 8.8% by weight. A front-side substrate according to any one of the preceding claims, wherein the material of the front-side substrate has a density of less than 3.25 g / cm³. 3 , preferably less than 3g / cm² 3 , particularly preferably less than 2.75g / cm² 3 . Front surface substrate according to one of the preceding claims, wherein the material of the front surface substrate a modulus of elasticity which is higher than 68 GPa, preferably higher than 70 GPa, particularly preferably higher than 72 GPa, and / or wherein the material of the front substrate has a modulus of elasticity which is lower than 78 GPa, preferably lower than 76 GPa, particularly preferably lower than 74 GPa. Front substrate according to one of the preceding claims, wherein the material of the front substrate has a coefficient of thermal expansion in a temperature range of 20°C to 300°C which is greater than 4xO. 6 K -1 , preferably larger than 5x10" 6 K -1 , especially preferably larger than 6x10" 6 K -1 , is even more preferred than 7xlO" 6 K -1A front-end substrate according to one of the preceding claims, wherein the front-end substrate has a dimension greater than 35 cm, preferably greater than 45 cm, particularly preferably greater than 60 cm, and / or wherein the front-end substrate has a dimension, particularly a second dimension, greater than 65 cm, preferably greater than 75 cm, particularly preferably greater than 90 cm. A front-end unit for a solar module, particularly for mobile applications, for example, mobile devices, means of transport, or manned or unmanned aerial vehicles, comprising: a front-end substrate according to one of the Claims 1 to 15 and an adhesive layer which is applied over a surface area to the front surface substrate.

17. Solar module, in particular for mobile applications, for example mobile devices, means of transport, means of transport or manned or unmanned aircraft, comprising: a front substrate according to one of claims 1 to 15, preferably a rear element, which is in particular designed as a module frame, a solar cell, which is preferably arranged between the rear element and the front substrate, and an adhesive layer, which connects the front substrate to the solar cell.

18. Front panel unit according to claim 16 or solar module according to claim 17, wherein the adhesive layer comprises at least one of the following materials: butyl polymer, EVA, PVB, SMP (silyl-modified polymer), transparent silicone.

19. Use of a front-side substrate according to any one of claims 1 to 15 or a front-side unit according to claim 16 for a solar module, in particular for mobile applications, for example mobile devices, means of transport, means of transport or manned or unmanned flying objects. Use of a solar module according to claim 16 for mobile applications, for example mobile devices, means of transport, means of transport or manned or unmanned aircraft.

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