Heating structure for a motor vehicle

Abstract

The invention relates to a heating structure (30), in particular intended to be installed in the passenger compartment of a vehicle, in particular a radiant panel, the heating structure (30) comprising at least one electrically resistive layer arranged to emit heat when an electric current flows through the layer (31), the structure further comprising an array of electrodes (32) comprising a plurality of contact electrodes (33) arranged in electrical contact with the electrically resistive layer so as to cause an electric current to flow through the electrically resistive layer, at least two of the contact electrodes being in contact with a region of the electrically resistive layer (31), the two contact electrodes facing each other so that an electric current can flow from one of the electrodes to the other of the contact electrodes through the region of the electrically resistive layer, the two contact electrodes (33) on either side of the region being of a selected shape so that the two electrodes are closer to each other over a portion (38) of the electrodes and remain further apart at the ends (39) of the electrodes.

Description

TECHNICAL FIELD

[0001] The present invention relates to a heating structure, in particular intended to be installed inside a passenger compartment of a vehicle, in particular a radiant panel. BACKGROUND

[0002] Generally, a radiant panel comprises a plurality of electrodes designed to provide heat by Joule heating via the supply of an electric current to an electrically conductive coating. Reference can be made, for example, to document US 2016 / 0059669 which describes such a radiant panel.

[0003] A radiant panel is a device generally comprising an electric circuit designed to provide heat by Joule heating by supplying an electric current to electrically resistive conductive elements. These can be filamentary elements or surface coatings. According to the prior art, the electrically conductive coating can be, for example, a layer of paint containing carbon particles and / or metal particles. One problem currently found is that it is difficult to obtain a uniform heating over the entire surface of the radiant panel, i.e. the heating temperature does not vary from one point to another on the surface of the radiant panel. Geometric constraints complicate this drawback, since the radiant panel is intended to be arranged in different parts of the passenger compartment (roof lining, doors, pillars, glove compartment, etc.). SUMMARY

[0004] The aim of the present invention is to provide an improved radiant panel.

[0005] The present invention thus relates to a heating structure, in particular a flexible or soft heating structure, in particular intended to be installed inside a passenger compartment of a vehicle, in particular a radiant panel, comprising at least one electrically resistive layer designed to generate a heat output when an electric current flows through this layer, the structure further comprising an array of electrodes comprising a plurality of contact electrodes arranged in electrical contact with the electrically resistive layer so as to direct the electric current through this electrically resistive layer, at least two of these contact electrodes being in contact with a zone of the electrically resistive layer, these two contact electrodes facing each other so that the electric current can flow from one of these electrodes to the other of said contact electrodes without flowing through a further contact electrode, through the zone of the electrically resistive layer, these two contact electrodes adjoining said zone having a shape selected so that the two electrodes are closer to each other over a part of the electrodes and remain further apart at the ends of these electrodes.

[0006] In one example of the invention, the two electrodes each comprise a single branch without any lateral branch.

[0007] According to the invention, the mutual distance between the two contact electrodes is smaller over a part of the electrodes and larger over another part of the electrodes. The part facing the smallest mutual distance is in particular substantially in the middle of the length of the contact electrodes.

[0008] The contact electrodes with variable mutual distance are connected to distribution electrodes, in particular parallel distribution electrodes, which are arranged such that the direction of the current flowing therein is opposite to each other. It can be said that there is a cross current in the distribution electrodes.

[0009] The resistance encountered by the current lines between the two electrodes and the resistance of the area through the resistance layer can thus be substantially uniform.

[0010] The invention makes it possible in particular to overcome the problem of uneven heating in the heating structure, in particular the radiation plate, in the case of association with a cross current. In particular, when using the cross flow method, a voltage drop is observed over the length of each electrode. This phenomenon results in a weaker current flowing through the center of the radiation plate.

[0011] Since the power delivered by the heating structure is proportional to the current flowing through the structure, this undesirable effect leads to uneven heating along the resistance layer. In some cases, this can result in thermal discomfort or thermal inefficiency. The invention makes it possible to have greater heating uniformity, in particular by adjusting the distance between the electrodes based on the value of the differential voltage loss.

[0012] In particular, by means of a suitable reduction of the mutual distance, the invention makes it possible to make the heating power output by the area of the resistance layer substantially uniform.

[0013] According to one aspect of the invention, the current flows in opposite directions in the two distribution electrodes.

[0014] According to one aspect of the invention, the distance between the two electrodes is minimal in the central part of each of the two electrodes, in particular substantially in the middle of the electrodes.

[0015] According to one aspect of the invention, the edge of at least one of the electrodes has a concavity facing away from the other edge of the electrode.

[0016] According to one aspect of the invention, at least one of the edges is rounded.

[0017] According to one aspect of the invention, at least one of the edges has a portion in the form of a straight segment.

[0018] According to one aspect of the invention, one of the edges of the electrodes is straight, while the other edge has a non-straight shape, in particular in the form of a rounding or a straight segment, in particular in the form of a triangular apex.

[0019] According to one aspect of the invention, the two electrodes exhibit a symmetry about an axis of symmetry over a large part of their length.

[0020] According to an aspect of the application, the heating structure comprises electrodes having two edges adjacent to the area of the resistive layer, and these two edges of the electrodes exhibit axial symmetry, and each of these edges has a concavity directed towards the other edge.

[0021] According to an aspect of the application, each of these symmetrical edges comprises for example a corner shape or a rounded shape, in particular the apex of the corner or the top of the rounding being substantially in the middle of the electrode.

[0022] According to an aspect of the application, the discrete electrodes have different shapes.

[0023] According to an aspect of the application, the contact electrodes located at the ends have different shapes with respect to the intermediate electrodes between these contact electrodes, in particular one edge being straight and the other edge being curved on the other side of the area of the resistive layer in the direction of the other electrode.

[0024] According to an aspect of the application, the array of electrodes comprises distribution electrodes arranged to guide the current from the power supply to the contact electrodes, several contact electrodes being connected to the same distribution electrode.

[0025] According to an aspect of the application, at least one of the distribution electrodes is rectilinear over at least a part of its length, and the contact electrodes associated with this distribution electrode are connected to this distribution electrode for example perpendicularly.

[0026] Naturally, the distribution electrodes can take different shapes, in particular with rounded curves. The distribution electrodes can or can not be parallel to each other.

[0027] According to an aspect of the application, the array of electrodes comprises at least two distribution electrodes which are parallel to each other over at least a part of their length, and their associated contact electrodes are arranged between these two distribution electrodes and alternate at a mutual distance which decreases as the voltage present between the pairs of electrodes decreases, to maintain a substantially uniform electric power between the pairs of contact electrodes.

[0028] According to an aspect of the application, the contact electrodes arranged between two distribution electrodes, which form part of the same group of contact electrodes, have only two values of mutual distance or at least three or more values of mutual distance.

[0029] According to an aspect of the application, the resistive layer is a layer deposited on a substrate, in particular by screen printing, which extends in particular between the two distribution electrodes associated with the group of contact electrodes.

[0030] According to an aspect of the application, the resistive layer in particular comprises carbon.

[0031] According to one aspect of the application, the electrodes are made of an electrically conductive material, in particular a metal, for example an ink loaded with electrically conductive particles, in particular an ink loaded with silver or copper particles. If necessary, the electrodes are metal adhesive strips, for example made of copper. These electrodes can be formed by depositing the material on a substrate, if applicable.

[0032] According to one aspect of the application, the electrically resistive layer associated with a group of contact electrodes is a continuous layer, or, as a variant, comprises a plurality of discrete electrically resistive elements forming the layer.

[0033] According to one aspect of the application, the contact electrodes of the same group have the same length.

[0034] According to one aspect of the application, the heating structure comprises a substrate carrying the electrically resistive layer and the electrodes. The substrate preferably has a thickness of less than 1 cm for a surface area of at least a few square centimetres.

[0035] The heating structure is in particular in the form of one or more layers.

[0036] The application also relates to a component of a passenger compartment of a motor vehicle, in particular a component to be integrated into a vehicle door, or in particular a component of a dashboard, a footwell trim, a headliner, an armrest, comprising a heating structure, in particular a radiant panel as described above.

[0037] According to one aspect of the application, the passenger compartment component comprising a heating structure, for example a radiant panel, is designed to be heated by thermal radiation (radiant panel) or by thermal conduction or thermal contact (contact heating structure) and not by convection heating (for example by the heat carried by moving air). In particular, no air flow passes through the heating structure for cooling or heating the passenger compartment. Preferably, the panel is separate from the air circulation system.

[0038] If necessary, the heating structure of the vehicle and the HVAC ("heating, ventilation and air conditioning") can be controlled in a coordinated manner.

[0039] The component forms an element of a parcel shelf or a door panel of the vehicle, for example, or a roof of the passenger compartment.

[0040] The application also relates to a heating structure having an electrically resistive layer and electrodes for heating the layer, the structure being designed to be integrated into a passenger compartment component comprising a decorative element visible from the inside of the passenger compartment, the decorative element being for example a finishing element of the passenger compartment, for example a fabric, leather or aesthetic covering. BRIEF DESCRIPTION OF DRAWINGS

[0041] It should be understood that the above-mentioned features and configurations of the groups are by no means restrictive. Other features, details and advantages of the application will become more clearly apparent from the detailed description given below, read in conjunction with the accompanying schematic drawings, which illustrate, by way of non-restrictive indication, several exemplary embodiments of the application:

[0042] Figure 1 is a schematic view of an exemplary embodiment of a radiant panel according to an exemplary embodiment of the application;

[0043] Figure 2 is a schematic view of the components of a radiant panel comprising the application;

[0044] Figure 3 is a schematic view of another example of the application,

[0045] Figure 4 is a schematic view of another example of the application. DETAILED DESCRIPTION

[0046] Figure 1 A radiant panel 1 forming a heating structure in the sense of the application is shown, which is designed to be installed inside a passenger compartment 3 of a vehicle.

[0047] The radiant panel 1 comprises a resistive layer 4 designed to generate a thermal output when an electric current passes through this layer 4.

[0048] The resistive layer 4 is for example an acrylic paint loaded with electrically conductive or semi-conductive particles. This conductive filler takes the form of for example carbon or graphite flakes.

[0049] The panel 1 also comprises an array of electrodes 5 comprising a plurality of contact electrodes 6 arranged in electrical contact with the resistive layer 4 in order to direct an electric current through this resistive layer 4.

[0050] The contact electrodes 6 are arranged with mutual distances Di between successive electrodes, said mutual distances being variable.

[0051] In the example described, the contact electrodes 6 are rectilinear and parallel to each other.

[0052] The array of electrodes 5 comprises distribution electrodes 8 designed to direct the electric current to the contact electrodes 6, one of these distribution electrodes 8 being connected to an electrical power source 9, for example of positive polarity. Another distribution electrode 8 is connected to another polarity, for example to ground.

[0053] The electric current thus flows through the distribution electrodes 8 which distribute the electric current into the contact electrodes 6. The electric current then flows in the resistive layer 4 before being collected at the contact electrodes 6 connected to the other distribution electrode 8.

[0054] Several contact electrodes 6 are connected to the same distribution electrode 8.

[0055] The distribution electrodes 8 are straight over part of their length, even over their entire length, and the contact electrodes 6 associated with these distribution electrodes 8 are connected perpendicularly to the associated distribution electrode 8.

[0056] Here, the array of electrodes 5 comprises two parallel distribution electrodes 8, and their associated contact electrodes 6 are arranged between these two distribution electrodes 8 and alternate with mutual distances Di, D2,... Di that decrease according to the decrease in the voltage Ui, U2,... Ui present between pairs of contact electrodes 6, so as to maintain a substantially uniform electric power between pairs of contact electrodes.

[0057] The contact electrodes 6 arranged between two distribution electrodes 8, which form the same group 14 of contact electrodes, have several mutual distance values Di, D2,... Di. In the example described, Di > D2 > D3 > D4, while Ui > U2 > U3 > U4 is the voltage between the contact electrodes 6.

[0058] The resistive layer 4 is a layer deposited on the substrate 16, in particular by screen printing, which extends in particular between the two distribution electrodes 8 associated with said group of contact electrodes. The substrate 16 is for example made of a non-woven material and is soft and flexible.

[0059] The contact electrodes 6 and the distribution electrodes 8 are made of an electrically conductive material, in particular a metal, for example an ink loaded with electrically conductive particles, in particular silver or copper particles.

[0060] In the example described, the resistive layer 4 associated with a group of contact electrodes is a continuous, substantially rectangular layer. Other shapes are naturally conceivable.

[0061] The contact electrodes 6 of the same group 14 have the same length. As a variant, the contact electrodes 6 can have different lengths.

[0062] In an example not shown, several pairs of distribution electrodes 8 can be provided, then there are several groups 14 of contact electrodes 6.

[0063] The passenger compartment part 19 of a motor vehicle, in particular a part to be integrated into a vehicle door, is provided with a radiating panel 1. Several parts can be provided in the passenger compartment.

[0064] The part 19 can comprise a decorative layer applied to the radiating panel. The decorative layer can for example be impermeable to air, for example made of leather.

[0065] If desired, the distribution electrodes 8 can have a more complex shape, for example with one or more rounded corners attached to straight sections.

[0066] In the example described, all the mutual distance values Ui of the group 15 are different. As a variant, certain mutual distance values of the same group can be identical, instead of all being different.

[0067] The substrate can be, for example, a sheet or a cloth.

[0068] The contact electrodes 6 and their associated distribution electrodes 8 are arranged in an interdigitated comb-like manner.

[0069] In one variant, the heating structure is used in a component of the passenger compartment, which is a passenger handrail, in which case the structure can heat the passengers' arms by thermal contact.

[0070] Figure 3 A heating structure 30 according to another exemplary embodiment of the application is shown, comprising a resistive layer 31 designed to produce a thermal output when an electric current flows through this layer 31, the structure 30 also comprising an array of electrodes 32 comprising a plurality of contact electrodes 33 arranged in electrical contact with the resistive layer 31 so as to direct the electric current through this resistive layer 31, these contact electrodes 33 being in contact with zones 35 of the resistive layer 31, these contact electrodes 33 facing each other so that the electric current can flow from one of these contact electrodes 33 to another of said contact electrodes 33 by flowing through this zone 35 of the resistive layer, in particular without flowing through a further contact electrode, the contact electrodes 33 bordering each zone 35 having a selected shape so that two adjacent contact electrodes 33 come close to each other over a portion 38 of the electrodes and remain further apart at the ends 39 of the electrodes.

[0071] The contact electrodes 33 each comprise a single branch, without any side branch.

[0072] The mutual distance between two adjacent contact electrodes 33 is smaller over a portion of the electrodes and larger over another portion of the electrodes. The portion facing the smallest mutual distance is in particular substantially in the middle 40 of the length of the contact electrodes 33.

[0073] The contact electrodes 33 with variable mutual distance are connected to distribution electrodes 42, in particular parallel distribution electrodes 42, arranged so that the direction of the electric current flowing in the distribution electrodes 42, represented by the arrows FF, are opposite to each other. It can be said that there is a cross current in the distribution electrodes.

[0074] Thus, in the contact electrodes, the electric current flows crosswise alternately, in particular the direction of the electric current alternates from one contact electrode to another contact electrode.

[0075] The current flows in opposite directions in the two distribution electrodes 42.

[0076] The distance between the two contact electrodes 33 is minimal at the respective middle 40 of the two electrodes.

[0077] In the example of Figure 3 the edge 44 of the intermediate contact electrode 33 has portions in the form of straight segments 45 forming respective corners 46.

[0078] As a variant, as Figure 4 shown, the edge 44 is rounded.

[0079] In Figure 3 and Figure 4 , each of the end contact electrodes 33 has a straight straight edge 49, while the other edge 44 has a non-straight shape, in particular rounded or in the form of straight segments, in particular in the form of a triangular apex.

[0080] The two electrodes exhibit a symmetry about an axis of symmetry DS over a substantial part of their length. The successive contact electrodes 33 are alternately connected to a distribution electrode 42 on one side and to the other distribution electrode on the other side. These contact electrodes 33 are thus not simultaneously connected to the two distribution electrodes 42.

[0081] The heating structure comprises intermediate contact electrodes 33 whose two edges are adjacent to the region 35 of the resistive layer, and these two edges 44 of the electrodes exhibit an axial symmetry about an axis DD, and each of these edges 44 has a concavity respectively directed towards the other edge 44 of the same electrode.

Claims

1. A heating structure (30) comprising at least one resistive layer designed to generate a thermal output when an electric current flows through the resistive layer (31), the structure further comprising an array of electrodes (32) comprising a plurality of contact electrodes (33) arranged in electrical contact with the resistive layer so as to direct an electric current through the resistive layer, at least two of these contact electrodes being in contact with a region of the resistive layer (31), the two contact electrodes facing each other so that an electric current can flow from one of these contact electrodes to the other of the contact electrodes by flowing through the region of the resistive layer, the two contact electrodes (33) contiguous with the region having a shape selected so that the two contact electrodes are close to each other over a portion (38) of the contact electrodes and remain further apart at the ends (39) of the contact electrodes.

2. The heating structure of claim 1, wherein, The distance between the two contact electrodes (33) is minimal at a central portion of each of the two contact electrodes.

3. The heating structure of claim 1, wherein, An edge (44) of at least one of the contact electrodes has a concavity facing the other edge.

4. The heating structure of claim 3, wherein, At least one of the edges (44) is rounded.

5. The heating structure of claim 3, wherein, At least one of the edges (44) has a portion in the form of a straight segment.

6. The heating structure of claim 3, wherein, One of the edges (49) of the contact electrodes is straight and the other edge has a non-straight shape.

7. The heating structure of claim 1, wherein, The two contact electrodes exhibit a symmetry about a symmetry axis DS over a majority of the length of the two contact electrodes.

8. The heating structure of claim 1, wherein, The heating structure comprises an intermediate contact electrode having two edges contiguous with a region of the resistive layer, and the two edges of the intermediate contact electrode exhibit an axial symmetry DD.

9. The heating structure of claim 1, wherein, The contact electrodes, having a variable mutual distance, are connected to distribution electrodes (42) arranged so that the direction of the electric current flowing in the distribution electrodes is opposite to each other.

10. The heating structure of claim 1, wherein, The heating structure (30) is a flexible or soft heating structure.

11. The heating structure of claim 1, wherein, The heating structure (30) is a radiant panel.

12. The heating structure of claim 1, wherein, The heating structure (30) is intended to be installed inside a passenger compartment of a vehicle.

13. The heating structure of claim 2, wherein, The distance between the two contact electrodes (33) is minimal at a middle of the two contact electrodes.

14. The heating structure of claim 6, wherein, The other edge is rounded.

15. The heating structure of claim 6, wherein, The other edge is in the form of a straight segment.

16. The heating structure of claim 6, wherein, The other edge is in the form of a triangular apex.

17. The heating structure of claim 9, wherein, The distribution electrodes (42) are parallel distribution electrodes.

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