Motor vehicle comprising a composite pane having a photovoltaic system

Abstract

The invention relates to a motor vehicle comprising a composite pane, wherein the composite pane comprises a photovoltaic system (1), an outer pane (9) and an inner pane (10), wherein the photovoltaic system (1) is arranged between the outer pane (9) and the inner pane (10), wherein the functional element (11) is arranged closer to the outer pane (9) than the photovoltaic cells (2), wherein the photovoltaic system (1) comprises a plurality of photovoltaic cells (2), a functional element (11), a shading detector, and a control device, wherein the photovoltaic cells (2) are designed to generate electrical energy when an energy-generation side of the photovoltaic cells (2) is exposed to electromagnetic radiation (4), wherein the functional element (11) covers the energy-generation side of the photovoltaic cells (2), wherein the functional element (11) has optical properties in a first state that differ from those in a second state, wherein the functional element (11) can be switched from the first state to the second state and vice versa by changing an electrical voltage applied to the functional element (11), wherein the functional element (11) is designed to scatter electromagnetic radiation (4) entering the functional element (11) more strongly in the second state than in the first state, wherein the shading detector is designed to detect shading of the photovoltaic cells (2), and wherein the control device is designed to switch the functional element (11) at least partially into the second state when shading of a subgroup of the photovoltaic cells (2) has been detected.

Description

[0001] SAINT-GOBAIN SEKURIT FRANCE 2024347-WO-PCT

[0002] 1

[0003] motor vehicle comprising a composite windscreen with a photovoltaic system

[0004] The present invention relates to a motor vehicle according to the preamble of claim 1, and to a method for controlling a photovoltaic system in such a motor vehicle.

[0005] It is known from the prior art to bridge or switch off the photovoltaic cells that are shaded during sunlight in a photovoltaic system with multiple photovoltaic cells in order to prevent them from impairing the efficiency of the photovoltaic system as resistance when other photovoltaic cells are not shaded at the same time.

[0006] Methods for increasing the efficiency of a photovoltaic system when a subgroup of the photovoltaic cells is shaded are known from WO 2016 / 123636 A1 and WO 2017 / 161358 A2.

[0007] In contrast, the present invention aims to further increase the efficiency of the photovoltaic system.

[0008] This problem is solved by a motor vehicle according to claim 1 and a method according to claim 7. Embodiments of the invention are specified in the dependent claims.

[0009] The motor vehicle includes a composite panel. The composite panel comprises a photovoltaic system, an outer panel, and an inner panel. For example, the composite panel can be located in the roof of the motor vehicle. For the purposes of this description, the outer panel is understood to be the panel that faces the environment when the composite panel is used as intended. For the purposes of this description, the inner panel is understood to be the panel that faces an interior space when the composite panel is used as intended.

[0010] The photovoltaic system is positioned between the outer and inner panes. The functional element is located closer to the outer pane than the photovoltaic cells, ensuring that the electromagnetic radiation radiating from the outside onto the laminated pane first passes through the functional element before reaching the photovoltaic cells. SAINT-GOBAIN SEKURIT FRANCE 2024347-WO-PCT

[0011] 2

[0012] The outer and inner panes are preferably made of glass, particularly preferably of soda-lime glass, as is common for window panes. However, one or both panes can also be made of other types of glass, such as quartz glass, borosilicate glass, or aluminosilicate glass, or of rigid, clear plastics, such as polycarbonate or polymethyl methacrylate. The thicknesses of the outer and inner panes are preferably from 0.5 mm to 5 mm, and particularly preferably from 1 mm to 3 mm, and are independent of each other. The photovoltaic system comprises several photovoltaic cells, a functional element, a shading detector, and a control device. The photovoltaic cells are configured to generate electrical energy when one of their energy-generating sides is exposed to electromagnetic radiation.The electromagnetic radiation can be, for example, light, especially sunlight.

[0013] The functional element covers the energy-generating sides of the photovoltaic cells. In this description, this means in particular that when the photovoltaic system is irradiated with electromagnetic radiation, the electromagnetic radiation must first pass through the functional element before it reaches the energy-generating sides of the photovoltaic cells.

[0014] The functional element exhibits different optical properties in a first state than in a second state. By changing the electrical voltage applied to the functional element, it can be switched from the first to the second state and vice versa. The functional element is designed to scatter electromagnetic radiation entering it more strongly in the second state than in the first state.

[0015] For example, the functional element can comprise an electrochromic material that changes its transparency to light depending on the electrical voltage. For example, the functional element can comprise liquid crystals (LC), in particular liquid crystals embedded in a polymer matrix (polymer dispersed liquid crystal, PDLC). For example, when an electrical voltage greater than or less than 0 V is applied to the functional element, the liquid crystals can be aligned in a common direction. In this state, the functional element is then transparent and / or clear. When the applied electrical voltage is 0 V, the liquid crystals can be randomly aligned, resulting in scattering of the light passing through the functional element. In SAINT-GOBAIN SEKURIT FRANCE 2024347-WO-PCT

[0016] 3. In this case, the functional element is no longer transparent, but may appear cloudy or milky, for example. It is also possible that the functional element is clear when an applied electrical voltage of 0 V is present, and becomes cloudy or milky due to light scattering when an electrical voltage greater or less than 0 V is applied. Thus, the functional element may change its transparency not so much by reducing the overall transmission, but rather by increasing scattering. In particular, it is possible that in the second state, the functional element scatters more than 90% of the incident electromagnetic radiation towards the energy-generating sides and thus reflects or absorbs less than 10%.

[0017] The shading detector is designed to detect shading of the photovoltaic cells. This can mean, in particular, detecting whether and which of the photovoltaic cells are shaded. The shading detection can be carried out in a manner already known from prior art photovoltaic systems.

[0018] The control device is designed to switch the functional element at least partially into the second state when shading is detected in a subgroup of the photovoltaic cells. It is also possible that the control device is designed to switch the functional element completely into the second state when shading is detected in the subgroup of photovoltaic cells.

[0019] The subgroup is not defined before the shading is detected. Rather, the detection of the shading results in the shaded photovoltaic cells forming the subgroup. In some cases, the subgroup may even consist of only a single photovoltaic cell.

[0020] It is particularly advantageous if the shading of the subgroup triggers the control device to switch the functional element at least partially or completely into the second state.

[0021] Such a photovoltaic system is particularly advantageous when only some of the photovoltaic cells are shaded. This can be beneficial, for example, when using the photovoltaic system in or on the roof of a motor vehicle, if some of the photovoltaic cells are shaded by a roof structure such as an antenna or by an object in the vicinity of the vehicle, such as SAINT-GOBAIN SEKURIT FRANCE 2024347-WO-PCT

[0022] 4. A tree is casting a shadow. It is also possible that an object on the roof is causing the shadow. Especially when the vehicle is moved, the size and position of shadows can change rapidly.

[0023] It is advantageous to switch the functional element to the second state instead of bypassing or switching off the photovoltaic cells, because, due to the scattering of electromagnetic radiation, a large proportion of the electromagnetic radiation continues to reach the energy-generating sides of the photovoltaic cells, and no photovoltaic cell needs to be switched off. Due to the scattering of electromagnetic radiation, a sufficiently large proportion of the electromagnetic radiation can reach photovoltaic cells that would otherwise be shaded without the functional element. When photovoltaic cells are bypassed or switched off, cells that are not shaded are often also switched off or bypassed. They then no longer contribute to energy generation. In contrast, with the photovoltaic system according to the invention, all photovoltaic cells can remain switched on and contribute to energy generation.Although the amount of energy generated decreases due to shading, the scattering of electromagnetic radiation makes it possible to keep all photovoltaic cells switched on, thus increasing the proportion of electromagnetic radiation used for energy generation compared to the state of the art.

[0024] Preferably, in its second state, the functional element scatters the electromagnetic radiation so strongly that, in the event of shading, as few or even no photovoltaic cells need to be switched off or bypassed. This can depend, in particular, on the distance between the functional element and the photovoltaic cells. If the distance is too small, it may be advantageous to switch off or bypass some of the photovoltaic cells despite the scattering. However, a small distance may be advantageous or even necessary for structural reasons. Practical tests have shown that the use of the functional element is still advantageous even with a distance of less than one centimeter between the functional element and the photovoltaic cells.If sufficient installation space is available, such as in a building window pane, it may be preferable to provide a distance of more than 3 cm, preferably more than 5 cm, between the functional element and the photovoltaic cells. SAINT-GOBAIN SEKURIT FRANCE 2024347-WO-PCT.

[0025] 5

[0026] According to one embodiment of the invention, the functional element can comprise several areas. These areas can be switched independently between the first and second states. This is advantageous so that if only a small number of the photovoltaic cells are shaded, the entire functional element does not have to be switched to the second state. Switching the entire functional element to the second state can result in lower energy generation losses compared to switching only some areas of the functional element to the second state.

[0027] According to one embodiment of the invention, the control device can be configured to switch the areas of the functional element that cover at least one photovoltaic cell from the subgroup to the second state. In particular, it is possible that the detection of shading triggers the switching of these areas to the second state. Furthermore, the control device can be configured to switch the areas of the functional element that cover photovoltaic cells not belonging to the subgroup to the first state or to leave them in the first state.

[0028] According to one embodiment of the invention, the functional element can comprise liquid crystals. This is a particularly simple way to create a functional element that can be switched between the first and second states. In the first state, the liquid crystals can be aligned due to an electrical voltage applied to the functional element, whereas in the second state, without an electrical voltage applied to the functional element, they are not aligned and therefore scatter electromagnetic radiation.

[0029] According to one embodiment of the invention, the functional element can be transparent in the first state and translucent in the second state. In this description, "transparent" is understood to mean, in particular, that the functional element is clear and see-through. In this description, "translucent" is understood to mean, in particular, that the functional element is cloudy and / or milky.

[0030] According to one embodiment of the invention, the composite disc can be arranged in the roof of the motor vehicle. This is particularly advantageous for generating energy. SAINT-GOBAIN SEKURIT FRANCE 2024347-WO-PCT

[0031] 6

[0032] In the method according to claim 7, the shading of the subgroup of photovoltaic cells is first detected. The detection then triggers the switching of at least one area of ​​the functional element to the second state. This area covers the photovoltaic cells of the subgroup. The detection can also trigger the switching of the entire functional element to the second state.

[0033] According to one embodiment of the invention, the functional element can only be partially switched to the second state. This can particularly mean that those areas of the functional element are switched to the first state or remain in the first state that exclusively cover unshaded photovoltaic cells.

[0034] It is particularly possible that the process has one or more features that are described in this description in connection with the photovoltaic system. In particular, features that are described in connection with the photovoltaic system in such a way that a component is designed for a specific function may correspond to the execution of that function in the process.

[0035] Further features and advantages of the present invention will become clear with reference to the following description of preferred embodiments and the accompanying figures. The same reference numerals are used for identical or similar components, features, or elements, and for components, features, or elements with identical or similar functions.

[0036] Fig. 1 shows a schematic top view of a photovoltaic system of a motor vehicle according to an embodiment of the invention;

[0037] Fig. 2 is a schematic top view of the photovoltaic system from Fig. 1 showing shading of the photovoltaic cells;

[0038] Fig. 3 shows a schematic top view of the photovoltaic system from Fig. 2 with a functional element partially switched to a second state; and

[0039] Fig. 4 shows a schematic sectional view of a composite windscreen of a motor vehicle according to an embodiment of the invention.

[0040] The photovoltaic system 1 comprises several photovoltaic cells 2, which are designed to generate electricity from electromagnetic radiation 4 directed at an energy generation side of the SAINT-GOBAIN SEKURIT FRANCE 2024347-WO-PCT

[0041] 7

[0042] Photovoltaic cells 2 are used to generate electrical energy. The photovoltaic system 1 also includes a functional element, which is not shown in Figures 1 and 2 for clarity and covers the photovoltaic cells 2.

[0043] In Figure 1, the sun 3 emits electromagnetic radiation 4 onto the photovoltaic cells 2. The functional element is completely in the first state, so that it is transparent and transmits the electromagnetic radiation to the photovoltaic cells with only negligible losses.

[0044] In Figure 2, a roof structure 5, for example an antenna, casts a shadow 6 on a first subgroup of the photovoltaic cells 2. Furthermore, a leaf 7 shades a second subgroup of the photovoltaic cells 2. A third subgroup of the photovoltaic cells 2 is free of shading and can generate electrical energy just as in the state shown in Figure 1.

[0045] In response to the shading of the first and second subgroups detected by the shading detector of the photovoltaic system 1 (not shown in the figures for clarity), some areas 8 of the functional element are switched to the second state. This is shown in Figure 3. In the second state, the areas 8 scatter a large proportion, preferably more than 90%, of the incident electromagnetic radiation 4. The scattered electromagnetic radiation 4 then reaches the photovoltaic cells 2 that are covered by the areas 8. Thus, there are no longer any completely or largely shaded photovoltaic cells 2. The photovoltaic cells 2 that would be shaded without the functional element now receive a sufficiently large proportion of the scattered electromagnetic radiation 4 so that they do not need to be bypassed or switched off. In this way, all photovoltaic cells can continue to contribute to energy generation.

[0046] Since the areas 8 can be switched particularly quickly from the first state to the second state and vice versa, a rapid response to changes in shading is possible. For example, if the leaf 7 is moved away from the photovoltaic system 1 by an air movement, the corresponding area 8 can be switched back to the first state, thus enabling even more efficient electrical energy generation. This is particularly advantageous when the photovoltaic system 1 is part of a vehicle's roof. In this case, the shadow 6 cast by the roof structure 5, for example, when passing SAINT-GOBAIN SEKURIT FRANCE 2024347-WO-PCT

[0047] 8 of a curve quickly move across other photovoltaic cells 2. The ability to quickly switch the areas 8 of the functional element from the first to the second state and vice versa allows for a rapid response to this situation.

[0048] The composite panel shown in Figure 4 comprises an outer panel 9, an inner panel 10, the functional element 11, and several photovoltaic cells 2, of which only one is shown due to the sectional view in Figure 4. The functional element 11 is arranged closer to the outer panel 9 than the photovoltaic cells 2, so that electromagnetic radiation striking the composite panel from the outside passes through the functional element 11 and reaches the photovoltaic cells 2. Therefore, by switching the functional element 11, or only some areas of the functional element 11, into the second state, the electromagnetic radiation can be scattered in such a way that none of the photovoltaic cells 2 need to be bypassed or switched off.

[0049] The distance between the functional element 11 and the photovoltaic cells 2 plays a crucial role in the efficiency of the electromagnetic radiation scattering principle. Therefore, spacing the functional element 11 from the photovoltaic cells 2 is advantageous. This spacing can be achieved, for example, by several thermoplastic intermediate layers and / or another functional element or elements. Preferably, the distance between the functional element 11 and the photovoltaic cells is at least 0.5 cm. A distance of more than 1 cm is particularly preferred. Naturally, the available installation space and any aesthetic criteria should also be considered when choosing the distance.

[0050] SAINT-GOBAIN SEKURIT FRANCE 2024347-WO-PCT

[0051] 9

[0052] Reference symbol list

[0053] 1 photovoltaic system

[0054] 2 photovoltaic cells 3 sun

[0055] 4 electromagnetic radiation

[0056] 5 Roof structure

[0057] 6 shadows

[0058] 7 sheets, 8 area

[0059] 9 Outer pane

[0060] 10 inner disc

[0061] 11 Functional element

Claims

SAINT-GOBAIN SEKURIT FRANCE 2024347-WO-PCT 10 Patent claims 1. Motor vehicle comprising a composite window, wherein the composite window comprises a photovoltaic system (1), an outer window (9) and an inner window (10), wherein the photovoltaic system (1) is arranged between the outer window (9) and the inner window (10), wherein the functional element (11) is arranged closer to the outer window (9) than the photovoltaic cells (2), wherein the photovoltaic system (1) comprises several photovoltaic cells (2), a functional element (11), a shading detector and a control device, wherein the photovoltaic cells (2) are configured to generate electrical energy when an energy-generating side of the photovoltaic cells (2) is exposed to electromagnetic radiation (4), wherein the functional element (11) covers the energy-generating side of the photovoltaic cells (2), wherein the functional element (11) has different optical properties in a first state than in a second state.wherein the functional element (11) can be switched from the first to the second state and vice versa by changing an electrical voltage applied to the functional element (11), wherein the functional element (11) is configured to scatter electromagnetic radiation (4) penetrating the functional element (11) more strongly in the second state than in the first state, characterized in that the shading detector is configured to detect shading of the photovoltaic cells (2), and wherein the control device is configured to switch the functional element (11) at least partially into the second state when shading has been detected in a subgroup of the photovoltaic cells (2).

2. Motor vehicle according to claim 1, characterized in that the functional element (11) comprises several areas (8), wherein the areas (8) can be switched independently of each other into the first state and into the second state.

3. Motor vehicle according to the previous claim, characterized in that the control device is configured to switch the areas (8) of the functional element (11) into the second state, which cover at least one photovoltaic cell (2) from the subgroup, and the areas of the SAINT-GOBAIN SEKURIT FRANCE 2024347-WO-PCT 11 to switch the functional element (11) to the first state, covering the photovoltaic cells (2) that do not belong to the subgroup.

4. Motor vehicle according to one of the preceding claims, characterized in that the functional element (11) comprises liquid crystals.

5. Motor vehicle according to one of the preceding claims, characterized in that the functional element (11) is transparent in the first state, wherein the functional element (11) is translucent in the second state.

6. Motor vehicle according to one of the preceding claims, characterized in that the composite window is arranged in a roof of the motor vehicle.

7. Method for controlling a photovoltaic system (1) in a motor vehicle according to one of the preceding claims, comprising the following steps: Detection of shading of the subset of photovoltaic cells (2); and thereby triggered switching at least one area (8) of the functional element (11) into the second state, wherein the area (8) covers the photovoltaic cells (2) of the subgroup.

8. Method according to the previous claim, characterized in that the functional element (11) is only partially switched to the second state.

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