WO2021032599A1

WO2021032599A1 - Sensor module for arranging on a motor vehicle

Info

Publication number: WO2021032599A1
Application number: PCT/EP2020/072793
Authority: WO
Inventors: Sascha Dietrich; Johannes Thannheimer
Original assignee: Webasto SE
Priority date: 2019-08-19
Filing date: 2020-08-13
Publication date: 2021-02-25
Also published as: DE102019122221A1

Abstract

The invention relates to a sensor module (04) for arranging on a motor vehicle (01), comprising a sensor housing (05), in which at least one environment sensor (06) is arranged. The sensor housing (05) has at least one light-transmissive see-through element (07, 12, 17, 23), and the see-through element (07, 12, 17, 23) can be heated by means of a heating element. The heating element is a thin-film electrode (09, 14, 18) arranged indirectly or directly on the interior or exterior of the see-through element (07, 12, 17, 23). Contact can be established between the thin-film electrode (09, 14, 18) and the electrical energy supply of the motor vehicle (01) by means of at least two contact elements (10, 16). The thin-film electrode (09, 14, 18) has an electrically conductive layer, which comprises silver nanowires (AgNWs) and/or indium tin oxide (ITO) and/or carbon nanotubes (CNTs) and is heated as electric current flows through.

Description

Sensor module for arrangement on a motor vehicle

The invention relates to a sensor module for arrangement on a motor vehicle according to the preamble of patent claim 1.

Autonomous or partially autonomous vehicles are becoming more and more widespread in vehicle technology. In order to enable the vehicle controller to control the motor vehicle autonomously or partially autonomously, a large number of environment sensors are required with which the environment of the motor vehicle is recorded and the respective traffic situation is determined from this. A sensor housing in which the environmental sensors are installed is used to protect the environment sensors from harmful environmental influences, for example moisture and air currents. The sensor housing itself can then in turn be attached to the vehicle, for example on the roof. For various environmental sensors to function, it is necessary for the light from the surroundings of the vehicle to reach the environmental sensor in the sensor housing. Various environmental sensors also work with emitted laser beams (LIDAR sensor). With these environment sensors it is necessary that the emitted light beam can be emitted from the environment sensor into the environment of the vehicle. In order to enable the respective light to pass through the sensor housing in one or both directions, sensor housings are known in which a light-permeable see-through element is present. The see-through element enables the environment sensor to be protected from negative environmental influences and at the same time enables light to pass through the wall of the sensor housing to the required extent. In the context of the invention, light permeability means that electromagnetic radiation can pass through in the wavelength range used by the environment sensor. The known environmental sensors work in a wavelength range from 300 nm to 2000 nm.

In order to ensure the functionality of the environment sensor in the sensor module under all climatic conditions, it is known that a heating element is provided on the see-through element of the sensor housing, with which the see-through element can be heated. This makes it possible in particular for the see-through element to be kept free of snow, ice and fog at temperatures below 10 ° C. This is because snow and ice can impair the passage of light through the see-through element that is necessary for the function of the environment sensor to such an extent that the environment sensor only functions to a limited extent or no longer functions at all. In this case, the autonomous or semi-autonomous control of the vehicle would have to be restricted or interrupted.

For the heating of see-through elements in vehicle construction, thick-film electrodes are known in which several heating wires are attached to the surface of the see-through element. A current flow through these heating wires releases heat so that the see-through element can be kept free of snow, ice and fog.

The disadvantage of heating the see-through element with heating wires is that these heating wires are themselves opaque and can thus interfere with the field of vision of the environment sensor. In addition, the manufacture of the heating element by attaching the heating wires to the see-through element is time-consuming and costly.

Another disadvantage is the inhomogeneous temperature distribution of this technology, which leads to uneven and delayed defrosting. As a result, the efficiency of such systems is limited, since the disadvantage of inhomogeneity is compensated by means of a higher current in order to ensure the desired defrosting behavior in a short time. In addition, an inhomogeneous heat distribution leads to mechanical stress in the heated material, which can lead to fatigue and failure. The object of the present invention is therefore to propose a sensor module whose see-through element can be heated with a heating element, which avoids the disadvantages of the prior art described above.

The sensor module according to the invention is based on the basic idea that the heating element is designed in the manner of a thin-film electrode. This thin-film electrode can be attached either directly or indirectly, for example using a carrier element, to the outside or inside of the see-through element. The thin-film electrode has at least two contact elements in order to contact the thin-film electrode with the electrical energy supply of the motor vehicle from the vehicle electrical system with the required voltage level. In order to be able to produce the thin-film electrode at the same time with high heating power with little effort for production, the invention provides that the thin-film electrode has an electrically conductive layer, the silver mano wires and / or indium tin oxide (ITO) and / or carbon nano -Tubes (CNT) includes. Conductive layers made from these special materials are translucent and heat up when electrical current flows through them to such an extent that the transparent element can be prevented from icing or misting. Silver nanowires can be synthesized wet-chemically, so that the result is a solution of silver nanowires dispersed in a dispersant. This dispersion can be applied in a simple manner to a surface provided for it. As the dispersant evaporates, a disordered network of silver nanowires is formed, which forms an electrically conductive thin-film electrode. This thin-film electrode made of silver nanowires is translucent and at the same time electrically conductive and can be heated highly effectively by means of a corresponding current flow. What kind of carbon nanotubes (CNT) are used in the electrically conductive layer of the thin-film electrode is basically arbitrary. It is particularly advantageous if the carbon nanotubes are designed in the manner of carbon nanobuds (CNB). Carbon nanobuds are modifications of carbon in the form of covalently bonded molecules made of single-walled carbon nanotubes and fullerenes. These carbon nanobuds form with suitable deposition a disordered network that is fully conductive and at the same time has sufficient light permeability.

In order to reduce the need for silver for the production of the thin-film electrode from silver nanowires, it is particularly advantageous if the silver nanowires of the thin-film electrode are embedded in a matrix of aluminum-doped zinc oxide. These thin-film electrodes, in which the silver mano wires are encapsulated in aluminum-doped zinc oxide (AZO), require considerably less silver than conventional silver grid electrodes, with a comparably high conductivity. Encapsulation with a thin AZO layer leads to a considerable increase in conductivity, as the AZO generates a conductive path between the silver wires. At the same time, the AZO matrix ensures mechanical fixation of the syllable mano wires on the respective substrate and protects the syllable mano wires from negative external influences, for example oxidation or sulfidization of the syllable mano wires.

Furthermore, it is particularly advantageous if the nanowires of the thin-film electrode are materially welded to one another at the contact points of the disordered network. The bond between the silver mano wires and the contact points increases the conductivity of the thin-film electrode considerably. In order to enable the integral welding of the contact points, the layer of silver mano wires can be heated with electricity after the evaporation of the dispersion until the silver in the contact points melts at least slightly.

By using the silver mano wires, the very good conductivity properties of silver can become highly effective. A surface density of 0.2 to 0.4 g / m ² , in particular a surface density of approximately 0.3 g / m ² , is sufficient, if necessary, to form a thin-film electrode with sufficient heating properties. The extremely thin layer thickness of the thin-film electrode with these low surface densities also ensures transparency of the thin-film electrode, which is crucial for the function of the environment sensor. The way in which the thin-film electrode is attached directly or indirectly to the light-permeable see-through element is basically arbitrary. According to a first preferred embodiment variant, the conductive layer, which comprises silver mano wires and / or indium tin oxide and / or carbon nanotubes, is deposited over the entire surface of the see-through element. By attaching the thin-film electrodes directly to the see-through element, highly effective production and high light permeability, ie high transparency in the wavelength range of the environment sensor, can be ensured, since additional layers are not required.

As an alternative to the full-surface deposition of the thin-film electrode directly on the see-through element, the conductive layer, which comprises silver nanowires and / or indium tin oxide and / or carbon nano-tubes, can also be fixed over the entire surface on a carrier element. The carrier element together with the thin-film electrode then forms a heating element carrier, which in turn can be fastened together on the see-through element.

For the production of the carrier layer as a carrier for the thin-film electrode, in particular a carrier element made of polymer film can be used, which is made of polycarbonate or polyethylene, for example. Polycarbonate is highly transparent and ensures easy viewing. In order to be able to fasten the heating element carrier simply and reliably on the see-through element, the carrier layer can be glued to the see-through element with an adhesive layer. In principle, it does not matter whether the thin-film electrode is glued onto the see-through element together with the adhesive layer or whether it remains on the opposite outside of the heating element carrier.

If the thin-film electrode is attached to a surface facing outward, the thin-film electrode can be protected by a protective layer. This protective layer is applied after the production of the thin-film electrode on the outward-facing side of the thin-film electrode.

If a protective layer is provided to protect the thin-film electrode, it is advantageous if the area of the protective layer is smaller than the area of the thin-film electrode. As a result of this difference in area, the thin-film electrode protrudes over the protective layer at least in some areas. In this way, these protruding surfaces of the thin-film electrode easily form contacting surfaces on which the thin-film electrode can be electrically contacted and connected to the on-board network. A particularly effective protection of the thin-film electrode is achieved if the protective layer comprises a lacquer layer.

A particularly high durability of the protective layer, in particular the protective layer made of silicate lacquer, is achieved if the protective layer is cured with a heat treatment and / or UV radiation after its application.

Which type of environment sensors is attached in the sensor housing of the sensor module is basically arbitrary as long as a passage of light through the see-through element of the sensor housing is necessary for the function of the environment sensor. The invention offers particularly great advantages when arranging LIDAR sensors and / or camera sensors and / or multi-camera sensors in the sensor housing of a sensor module.

The type of use for which the sensor module is used is still basically arbitrary. The invention offers particularly great advantages for sensor modules in which the sensor module is attached to a roof module to form a vehicle roof.

The subject of the invention is therefore also a roof module with a sensor module designed according to the invention.

In principle, this roof module according to the invention can be used both in passenger cars and in commercial vehicles such as delivery vans or tractors for trucks. It can be designed as a pure fixed roof or also be provided with a roof opening system and thus form a closable roof opening.

Furthermore, such a roof module preferably forms a structural unit which comprises in an integrated manner devices for autonomous driving or for partially autonomous driving supported by vehicle assistance systems and which can be placed on a vehicle shell by a vehicle manufacturer.

The invention also relates to a motor vehicle with a sensor module or a roof module of the type described above. Various embodiments of the invention are shown schematically in the drawing and are explained below by way of example. Show it:

FIG. 1 shows a motor vehicle with four sensor modules arranged on a roof module in a schematic view from above; FIG. 2 shows a sensor module according to FIG. 1 in a schematic cross section;

FIG. 3 shows the see-through element of the sensor module according to FIG. 2 in a schematic cross section;

FIG. 4 shows a second embodiment of a see-through element in a schematic cross section; FIG. 5 shows the see-through element according to FIG. 4 in a side view;

FIG. 6 shows a further embodiment of a see-through element in a schematic cross section; and

FIG. 7 shows a further embodiment of a see-through element in a schematic cross section. Figure 1 shows a motor vehicle 1 in a schematic view from above. To form the vehicle roof 2, a roof module 3 is attached to the vehicle body. On the outside of the roof module 3 facing upward, four sensor modules 4 are attached, each of which contains at least one environment sensor, for example a LIDAR sensor. The field sensors built into the sensor modules 4 enable the traffic situation surrounding the motor vehicle to be recorded in order to be able to implement the motor vehicle 1 in an autonomous or partially autonomous manner.

Figure 2 shows the sensor module 4 in a schematic section. The sensor module 4 is shown to the extent that it is necessary to understand the invention. An environment sensor 6 is attached in the water- and dust-tight encapsulated sensor housing 5. The sensor housing 5 itself is attached to the roof module 3. In order to enable the function of the environment sensor, a transparent see-through element 7 is attached to the front of the sensor housing 5, so that light can pass through the see-through element 7 in both directions.

Figure 3 shows the see-through element 7 in cross section. For easier understanding, the environment sensor 6 is also shown schematically with the corresponding light path. The see-through element 7 comprises a carrier element 8 to which a thin-film electrode 9 made of silver nanowires has been applied. Contacting elements 10 are provided on two side edges of the thin-film electrode 9 in order to be able to connect the thin-film electrode 9 to the electrical power supply of the vehicle electrical system. To protect the thin-film electrode 9 from undesirable environmental influences, a protective layer 11 made of lacquer is applied to the outside of the see-through element 7. The silver nanowires in the thin-film electrode 9 form a disordered network which is materially welded at the contact points. The disordered network of silver nanowires is also embedded in a matrix made of aluminum-doped zinc oxide.

FIG. 4 shows a second embodiment of a see-through element 12. A thin-film electrode 14 consisting of carbon nanobuds is deposited on a carrier element 13. To protect the thin-film electrode, a protective layer 15 is also attached to the outside of the thin-film electrodes.

Figure 5 shows the see-through element 12 in a view from the front. It can be seen that the side surfaces of the carrier element 13, the thin-film electrodes and the protective layer 15 each have a slight difference in area. Due to the difference in area between the thin-film electrode 14 and the protective layer 15, the thin-film electrode 14 projects laterally over the protective layer. The protruding surfaces 16 can thus be used to make contact with the thin-film electrode 14.

FIG. 6 shows a further embodiment of a see-through element 17. In the see-through element 17, a thin-film electrode 18 made of indium-tin-oxide and a carrier element 19 form a heating element carrier 20 that is to be manufactured separately glued. FIG. 7 shows a further embodiment of a see-through element 23. In the see-through element 23, the heating element carrier 20, consisting of thin-film electrode 18 and carrier element 19, is glued to the outside of carrier element 22 by means of an adhesive layer 24. In order to protect the heating element carrier 20 from environmentally harmful influences, a protective layer 25 is applied to the outside of the carrier element 19.

List of reference symbols

1 motor vehicle

2 vehicle roof

3 roof module 4 sensor module

5 sensor housing

6 environment sensor

7 see-through element

8 Carrier element 9 Thin-film electrode (silver nanowires)

10 contact element

11 protective layer

12 see-through element

13 Carrier element 14 Thin-film electrode (carbon nanobuds)

15 protective layer

16 overhang

17 see-through element

18 thin-film electrode (indium tin oxide) 19 carrier element

20 heating element carriers

21 adhesive layer

22 support element

23 see-through element 24 adhesive layer

25 protective layer

Claims

1. Sensor module (4) for arrangement on a motor vehicle (1) with a sensor housing (5) in which at least one environment sensor (6) is arranged, with the sensor housing (5) having at least one transparent element (7, 12, 17) , 23) and the see-through element (7, 12, 17, 23) can be heated with a heating element, characterized in that the heating element is in the form of a directly or indirectly on the inside or outside of the see-through element (7, 12, 17, 23 ) arranged thin-film electrode (9, 14, 18) is formed, wherein the

The thin-film electrode (9, 14, 18) can be contacted with the electrical energy supply of the motor vehicle (1) via at least two contact elements (10, 16), and the thin-film electrode (9, 14, 18) has an electrically conductive layer, the silver mano wires (SND ) and / or Indium-Tin-Oxide (ITO) and / or Carbon-Nano-Tubes (CNT) and which are in the flow of electrical

Electricity heated.

2. Sensor module according to claim 1, characterized in that the carbon nanotubes (CNT) in the electrically conductive layer of the thin-film electrode (9, 14,

18) are designed in the manner of carbon nanobuds (CNB).

3. Sensor module according to claim 1 or 2, characterized in that the syllable mano wires of the thin-film electrode (9) form a disordered network.

4. Sensor module according to one of claims 1 to 3, characterized in that the silver mano wires of the thin-film electrode (9) in a matrix of aluminum doped zinc oxide are embedded.

5. Sensor module according to claim 4, characterized in that the silver nanowires of the thin-film electrode (9) are materially welded to one another at the contact points of the network.

6. Sensor module according to one of claims 1 to 5, characterized in that the layer of the thin-film electrode (9) comprising silver nanowires has a surface density of 0.2 to 0.4 g / m ² .

7. Sensor module according to one of claims 1 to 6, characterized in that the conductive layer, which comprises silver nanowires and / or indium tin oxide (ITO) and / or carbon tubes (CNT), covers the entire surface of the see-through element (7, 12, 17, 23) is deposited.

8. Sensor module according to one of claims 1 to 6, characterized in that the conductive layer comprising silver nanowires and / or indium tin oxide (ITO) and / or carbon nanotubes (CNT) over the entire surface on a carrier element ( 19) is fixed and thereby forms a heating element carrier (20).

9. Sensor module according to claim 8, characterized in that the carrier element (19) is made from a polymer film.

10. Sensor module according to claim 8 or 9, characterized in that the heating element carrier (20) is fastened with an adhesive layer (21, 24) on the inside or outside of the see-through element (17, 23).

11. Sensor module according to one of claims 1 to 10, characterized in that a protective layer (11, 15) is provided on the outwardly facing side of the thin-film electrode (9, 14).

12. Sensor module according to claim 11, characterized in that the area of the protective layer (15) is smaller than the area of the thin-film electrode (14), wherein the protruding surfaces (16) of the thin-film electrode (14) protruding from the protective layer (15) form contact-making elements on which the thin-film electrode (14) can be electrically contacted.

13. Sensor module according to claim 11 or 12, characterized in that the protective layer (11, 15) comprises a lacquer layer.

14. Sensor module according to one of claims 11 to 13, characterized in that the protective layer (11, 15) is hardened by heat treatment and / or UV radiation.

15. Sensor module according to one of claims 1 to 14, characterized in that the environment sensor (6) is designed in the manner of a LIDAR sensor and / or in the manner of a camera sensor and / or in the manner of a multi-camera sensor.

16. Sensor module according to one of claims 1 to 15, characterized in that the sensor module (4) is attached to a roof module (3) to form a vehicle roof (2).

17. Roof module for a motor vehicle, comprising a sensor module according to one of the

Claims 1 to 16.

18. Motor vehicle, comprising a sensor module according to one of claims 1 to 16 or a roof module according to claim 17.