Heating device for an exhaust system and associated manufacturing process

Abstract

Heating device for an exhaust system and associated manufacturing method. The heating device (1) comprises first and second electrodes (5, 7) fixed to a heating plate (3) comprising a plurality of arms (19, 21), each having a proximal end (23) facing a first longitudinal side of the heating plate (3) and a distal end (25) facing a second longitudinal side of the heating plate (3). The arms (19, 21) are separated by slots (27), each opening at at least one longitudinal end. The proximal end (23) and / or distal end (25) of each arm (19, 21) is connected to the proximal end (23) and / or distal end (25) of an adjacent arm (19, 21). The electrodes (5, 7) are connected to the proximal ends (23) of the first intermediate branches (31) and the second intermediate branches (33), respectively. Figure for the abbreviation: Figure 1

Description

Title of the invention: Heating device for an exhaust system and associated manufacturing method

[0001] The present invention relates generally to a heating device for a vehicle exhaust system.

[0002] Such a device may include a heating plate made of an electrically conductive material and first and second electrodes fixed to the heating plate.

[0003] The heating plate may comprise a plurality of elongated branches along a longitudinal direction, the branches being juxtaposed along a transverse direction and separated from each other by longitudinal slots.

[0004] The electrodes are connected to the two branches located at the ends of the alignment.

[0005] The heating plate thus defines a winding path for the electric current, from one end branch to the other.

[0006] The two electrodes must be connected to an electrical harness, electrically connecting the heating plate to an electrical current source, typically to the vehicle's battery.

[0007] Connecting the electrodes to the beam is relatively complex and expensive.

[0008] In this context, the invention aims to provide a heating device allowing a simpler connection of the electrodes to the electrical bundle.

[0009] To this end, the invention relates to a heating device for a vehicle exhaust system, the heating device comprising a heating plate made of an electrically conductive material and first and second electrodes fixed to the heating plate, the heating plate comprising a plurality of elongated branches along a longitudinal direction, the branches being juxtaposed along a transverse direction and forming a transverse alignment having two end branches located at the two transverse ends of the alignment and intermediate branches arranged between the end branches, each branch having a proximal end turned to a first longitudinal side of the heating plate and a distal end turned to a second longitudinal side of the heating plate opposite to the first side,the branches being separated from each other by longitudinal slits, each opening at at least one longitudinal end, the proximal end and / or the distal end of each branch being connected respectively to the proximal end and / or the distal end of a neighboring branch in alignment;

[0010] the first and second electrodes being connected to the proximal ends of a first of the intermediate branches and second of the intermediate branches respectively.

[0011] Because the first and second electrodes are connected to the proximal ends of two intermediate branches, and not to the two terminal branches, the first and second electrodes are relatively close to each other. Therefore, it is simpler to connect them to the electrical harness.

[0012] The heating device may also have one or more of the following characteristics, considered individually or in all technically possible combinations: - The first and second intermediate branches are close together in alignment. - The first and second intermediate branches are located transversely in the center of the alignment. - The heating plate includes:

[0013] - a first winding path for the electric current, comprising the first intermediate branch, a final branch and all branches located in alignment between the first intermediate branch and the final branch, the final branch being either one of the end branches or the intermediate branch adjacent to the end branch in alignment;

[0014] - a second winding path for the electric current, comprising a plurality of neighboring branches in alignment;

[0015] - a distribution bar, connecting the distal end of the last branch of the first winding path at the distal end of one of the branches of the second winding path. - The first and second winding paths are made of a relatively less resistive electrical material and the distribution bar is made of a relatively more resistive electrical material. - The first intermediate branch is adjacent in alignment to one of the first of the two end branches, the second intermediate branch is adjacent in alignment to one of the second of the two end branches, the heating plate comprising a first distribution bar connecting the first electrode to the proximal end of the first intermediate branch and / or a second distribution bar connecting the second electrode to the proximal end of the second intermediate branch, the electrically conductive material having a first density in the intermediate branches, the electrically conductive material having a second density lower than the first in the end branches. - The heating plate is obtained by additive manufacturing. - The first and second electrodes are obtained by additive manufacturing with the heating plate. - The heating device comprises an annular housing internally delimiting a vacuum, the first electrode being directly connected to a terminal section of the first intermediate branch housed in the annular housing, the first intermediate branch having a central section passing through the vacuum and having a given central longitudinal length, said terminal section housed in the housing having a length less than 20% of said central longitudinal length.

[0016] According to a second aspect, the invention relates to a method for manufacturing a heating device having the above characteristics; the method comprises the following successive steps:

[0017] - obtaining the heating plate and the first and second electrodes;

[0018] - insertion of an edge of the heating plate into an annular housing;

[0019] - welding of the first electrode to the proximal end of the first branch in termedial, a point of said first intermediate branch being electrically connected to ground during welding.

[0020] Other features and advantages of the invention will become apparent from the detailed description given below, by way of example and not limitation, with reference to the accompanying figures, among which:

[0021] [Fig-1] Fig. 1 is a schematic top-view representation of a device heating system conforming to a first embodiment of the invention;

[0022] [Fig.2] The [Fig.2] is a schematic top view representation of a heating element for a second embodiment of the invention.

[0023] The heating device 1 shown in [Fig.1] is intended to be integrated into a vehicle exhaust system.

[0024] The vehicle is typically a motor vehicle such as a car, truck, bus, etc.

[0025] The exhaust system is designed to collect the exhaust gases emitted by the vehicle's internal combustion engine and release them into the atmosphere after purification.

[0026] In particular, catalytic purification elements are provided in the exhaust system. These catalytic elements only become effective when their temperature exceeds a critical value.

[0027] Therefore, it is advantageous to integrate a heating device into the exhaust system, making it possible to accelerate the temperature rise of the catalytic converter in the event of a cold start of the internal combustion engine. The exhaust gases passing through the heating device transfer by convection the thermal energy given off by the heating device to the catalytic converter. talytic.

[0028] Alternatively, the heating device heats the catalytic purification unit by radiation.

[0029] The heating device 1 comprises a heating plate 3 made of an electrically conductive material and first and second electrodes 5, 7 fixed to the heating plate 3.

[0030] The first and second electrodes 5 and 7 electrically connect the heating plate 3 to the two terminals of an electrical generator not shown, via a bundle of electrical cables also not shown.

[0031] The heating plate 3 is flat. In the example shown, it is circular. Alternatively, it is oval or has any other suitable shape.

[0032] The heating plate 3 has a central zone 9 and a peripheral edge 11 surrounding the central zone 9.

[0033] The heating device 1 further comprises an annular housing 13, internally delimiting a void 14.

[0034] The peripheral edge 11 of the heating plate 3 is engaged in the annular housing 13.

[0035] The central zone 9 occupies the void 14.

[0036] In [Fig. 1], the annular housing 13 is schematically represented by two concentric circles.

[0037] The heating plate 3 has a geometric center C shown in [Fig. 1]. Considered in a plane perpendicular to the heating plate 3 and passing through the center C, the annular housing 13 has a U-shaped cross-section, open towards the center C.

[0038] The annular housing 13 thus defines an annular groove, open radially towards the inside of the annular housing 13 and in which the peripheral edge 11 of the heating plate 3 is engaged.

[0039] The annular housing 13 thus has a cylindrical base 15 and two annular side walls 17 integral with the cylindrical base 15. The annular housing 13 has radially, opposite the cylindrical base 15, an opening through which the peripheral edge 11 of the heating plate 3 is engaged inside the annular housing 13.

[0040] The heating device 1 is housed in a component of the exhaust line, for example inside the casing receiving the catalytic converter. It is attached to this casing by means of the annular housing 13.

[0041] As illustrated in [Fig. 1], the heating plate 3 comprises a plurality of branches 19, 21 elongated along a longitudinal direction L, indicated by an arrow in [Fig. 1]. The branches 19, 21 are juxtaposed along a transverse direction T, indicated by an arrow in [Fig. 1], and thus form an alignment transverse.

[0042] The transverse alignment has two end branches 19 located at the two opposite transverse ends of the alignment.

[0043] The transverse alignment also includes intermediate branches 21 arranged between the two end branches 19.

[0044] Each branch 19, 21 has a proximal end 23 turned towards a first longitudinal side of the heating plate 3, referred to herein as the proximal side, and a distal end 25 turned towards a second longitudinal side of the heating plate 3, opposite to the first side and referred to herein as the distal side.

[0045] Branches 19, 21 are substantially straight.

[0046] The branches 19, 21 are separated from each other by longitudinal slits 27 tudinales, each opening at at least one longitudinal end.

[0047] The proximal end 23 and / or the distal end 25 of each branch 19, 21 is connected respectively to the proximal end 23 and / or the distal end 25 of a neighboring branch 19, 21 in alignment.

[0048] As can be seen in the figures, the proximal ends 23 are connected to each other by elbows 29, and similarly the distal ends 25 are connected to each other by elbows 29. The elbows 29 form U-shaped bends. The longitudinal slots 27 are closed at the elbows 29.

[0049] The first and second electrodes 5, 7 are connected to the proximal ends 23 respectively of a first intermediate branch, referenced 31, and of a second of the intermediate branches, referenced 33.

[0050] Advantageously, and as shown in [Fig.1], the first and second intermediate branches 31, 33 are close in alignment.

[0051] Preferably, they are located transversely to the center of the alignment.

[0052] As a result, the heating plate 3 has a first winding path 35 for the electric current, comprising the first intermediate branch 31, a last branch and all branches located in alignment between the first intermediate branch 31 and the last branch.

[0053] In the example shown, the last branch is one of the two end branches 19. Alternatively, the last branch is the intermediate branch 21 adjacent to the end branch 19 in the alignment.

[0054] The heating plate 3 also includes a second winding path 37 for the electric current, comprising a plurality of branches 19, 21 close together in alignment.

[0055] In the example shown, the second winding path 37 includes the second intermediate branch 33, a final branch and all branches located in the alignment between the second intermediate branch 33 and the final branch.

[0056] The last branch here is the other end branch 19. Alternatively, the last branch is the intermediate branch 21 adjacent to said end branch 19.

[0057] The heating plate 3, as seen in [Fig. 1], also includes a distribution bar 39, connecting the distal end 25 of the last branch of the first winding path 35, to the distal end 25 of one of the branches of the second winding path 37.

[0058] In the example shown, the distribution bar 39 connects the respective distal ends 25 of the last branches of the first and second winding paths 35, 37.

[0059] More specifically, the distribution bar 39 connects the respective distal ends 25 of the two end branches 19.

[0060] The distribution bar 39 is entirely formed in the peripheral edge 11 of the heating plate 3.

[0061] The peripheral edge 11 corresponds to the part of the heating plate 3 which is housed inside the annular casing 13.

[0062] The bends 29 are located inside the annular housing 13. They are formed in the peripheral edge 11, typically entirely in the peripheral edge 11.

[0063] The distribution bar 39 is located radially outwards from the elbows 29 connecting the distal ends 25 of the branches 19, 21 to each other.

[0064] It is separated from these elbows 29 by a circumferential slot 4L

[0065] The distribution bar 39 is thus located on the distal side of the heating plate 3, opposite the first and second electrodes 5, 7.

[0066] In the example shown, the slots 27 open alternately on the proximal and distal sides of the heating plate 3.

[0067] The opening slots 27 on the distal side open into the circumferential slot 4L

[0068] The slots 27 opening from the proximal side extend to the edge of the heating plate 3.

[0069] The slot 27 separating the first intermediate branch 31 from the second intermediate branch 33 is open at both ends.

[0070] The slots 27 separating the end branches 19 from the neighboring intermediate branches 21 open into the circumferential slot 4L

[0071] The electrically conductive material constituting the heating plate 3 is advantageously a porous material, through which the exhaust gases can flow. The pores are interconnected.

[0072] The density of the porous material is adjusted by varying the number and / or size of the pores.

[0073] Advantageously, the first and second winding paths 35, 37 are made of a relatively less dense material. In contrast, the distribution bar 39 is made of a relatively denser material.

[0074] Typically, the distribution bar 39 has a lower pore density than branches 19, 21, 31, 33, or has smaller pores.

[0075] Thus, the electric current flowing through the distribution bar 39 will generate a moderate amount of heat.

[0076] This prevents the formation of hot spots at the distribution bar 39.

[0077] Advantageously, the heating plate 3 is obtained by additive manufacturing.

[0078] In particular, branches 19, 21, 31, 33 and distribution bar 39 came from material and are obtained together, as a single piece, by additive manufacturing.

[0079] The first intermediate branch 31 has a terminal section 42 housed in the annular casing 13. It also has a central section 43 passing through the void 14.

[0080] The terminal section 42 corresponds to the entire part of the first intermediate branch 31 housed in the casing 13. It includes the proximal end 23 of the first intermediate branch 31.

[0081] The central section 43 corresponds to the entire part of the first intermediate branch 31 housed in the void 14. It extends between the two opposite sides of the annular housing 13. The terminal section 42 is directly connected to the central section 43.

[0082] The first electrode 5 is directly connected to the terminal section 42.

[0083] It extends longitudinally, in the plane of the heating plate 3, radially outwards from the annular housing 13 relative to the center C.

[0084] An orifice 44 is provided in the bottom 15 of the annular housing 13. The first electrode 5 is connected to a terminal surface 45 of the terminal section 42 through the orifice 44.

[0085] The central section 43 has a given central longitudinal length.

[0086] The terminal section 42 housed in the annular casing 13 has a length less than 20% of said central longitudinal length, preferably a length less than 15% of the central longitudinal length, and even more preferably a length less than 10% of the central longitudinal length.

[0087] The terminal section 42 extends obliquely with respect to the longitudinal direction L. If we follow the terminal section 42 from the central section 43, it extends radially outwards from the heating plate 3, moving away transversely from the second electrode 7.

[0088] The first electrode 5 is thus located longitudinally in the extension of the slit 27 separating the first intermediate branch 31 from the neighbouring intermediate branch 21.

[0089] The second intermediate branch 33 has a terminal segment 46 housed in the annular case 13. It also features a central section 47 passing through the void 14.

[0090] The terminal section 46 corresponds to the entire part of the second intermediate branch 33 housed in the annular casing 13. It includes the proximal end 23 of the second intermediate branch 33.

[0091] The central section 47 corresponds to the entire part of the second intermediate branch 33 housed in the void 14. It extends between the two opposite sides of the annular housing 13. The terminal section 46 is directly connected to the central section 47.

[0092] The second electrode 7 is directly connected to the terminal section 46.

[0093] It extends longitudinally, in the plane of the heating plate 3, radially outwards from the annular housing 13 relative to the center C.

[0094] An orifice 48 is provided in the bottom 15 of the annular housing 13. The second electrode 7 is connected to a terminal surface 49 of the terminal section 46 through the orifice 48.

[0095] The central section 47 has a given central longitudinal length.

[0096] The terminal section 46 housed in the annular casing 13 has a length less than 20% of said central longitudinal length, preferably a length less than 15% of the central longitudinal length, and even more preferably a length less than 10% of the central longitudinal length.

[0097] The terminal section 46 extends obliquely with respect to the longitudinal direction L. If we follow the terminal section 46 from the central section 47, it extends radially outwards from the heating plate 3, moving away transversely from the second electrode 7.

[0098] The second electrode 7 is thus located longitudinally in the extension of the slit 27 separating the second intermediate branch 33 from the neighbouring intermediate branch 21.

[0099] The terminal sections 42 and 46 thus together define a V.

[0100] The terminal surfaces 45 and 49, to which are welded respectively the first and second electrodes 5, 7, extend in the same plane, substantially perpendicular to the longitudinal direction L.

[0101] Electrodes 5 and 7 are parallel to each other, and are located a short distance apart.

[0102] The invention also relates to a method for manufacturing a heating device 1.

[0103] The process is particularly well suited for manufacturing the heating device 1 according to the first embodiment of the invention, shown in [Fig.1].

[0104] The process comprises the following successive steps:

[0105] - Obtaining the heating plate 3 and the first and second electrodes 5, 7;

[0106] - Insertion of an edge 11 of the heating plate 3 into an annular housing 13;

[0107] - Welding of the first electrode 5 to the proximal end 23 of the first intermediate branch 31, a point 51 of said first intermediate branch 31 being electrically connected to ground during welding.

[0108] The heating plate 3 and the first and second electrodes 5, 7 are as described above.

[0109] The ring housing 13 is as described above.

[0110] The first intermediate branch 31 is as described above.

[0111] The second intermediate branch 33 is as described above.

[0112] The first electrode 5 is welded to the terminal surface 45. The point 51 of the first intermediate branch 31 connected to ground is located in the central section 43 of the first intermediate branch 31.

[0113] Given the length of the terminal section 42 of the first intermediate branch 31, the electric current lines running from the terminal surface 45 to the point 51 are distributed uniformly in the section of the first intermediate branch 31. The electric current is thus not concentrated in a limited area of ​​the first intermediate branch 31, which could cause preferential melting of a part of the terminal surface 45, and create weld quality problems.

[0114] Typically, the process also includes a step of welding the second electrode 7 to the proximal end 23 of the second intermediate branch 33, a point 53 of the second intermediate branch 33 being electrically connected to ground during welding.

[0115] The second electrode 7 is welded to the terminal surface 49. The point 53 of the second intermediate branch 31 connected to ground is located in the central section 47 of the second intermediate branch 33.

[0116] The technical advantages are those mentioned above for welding the first electrode 5.

[0117] A second embodiment will now be described, with reference to [Fig. 2].

[0118] Only the points by which the second embodiment differs from the first will be detailed below. Identical elements or elements performing the same functions will be designated by the same reference numerals.

[0119] In the second embodiment, the first and second electrodes 5, 7 are advantageously obtained by additive manufacturing with the heating plate 3.

[0120] In other words, they came from the material with the heating plate 3 in the same material.

[0121] Furthermore, the first intermediate branch 31, to which the first electrode 5, is adjacent in alignment to one of the first of the two end branches 19.

[0122] In other words, the first intermediate branch 31 is the second to last branch in the alignment.

[0123] Advantageously, the second intermediate branch 33 is close in alignment with the second of the two end branches 19.

[0124] In other words, the second intermediate branch 33 is the penultimate branch in the alignment, opposite the first intermediate branch 31.

[0125] In order to allow the arrangement of the first and second electrodes 5, 7 parallel to each other and close to each other, the heating plate 3 includes a first distribution bar 55 connecting the first electrode 5 to the proximal end 23 of the first intermediate branch 31.

[0126] Similarly, the heating plate 3 includes a second distribution bar 57, connecting the second electrode 7 to the proximal end 23 of the second intermediate branch 33.

[0127] The first and second distribution bars 55, 57 are circumferentially oriented. They are entirely formed in the peripheral edge 11 of the heating plate 3. They are located radially towards the outside of the heating plate 3 with respect to the bends 29 connecting the proximal ends 23 of the branches 19, 21 to each other.

[0128] Circumferential slots 59, 61 separate the first and second distribution bars 55, 57 from the elbows 29. Some of the longitudinal slots 27 open into the circumferential slots 59, 61 on the proximal side of the heating plate 3.

[0129] The first and second distribution bars 55, 57 extend circumferentially towards each other from the first intermediate branch 31 and the second intermediate branch 33 respectively.

[0130] The terminal surfaces 45, 49, carrying the first and second electrodes 5, 7, are provided at the ends of the first and second distribution bars 55, 57. They extend in the same plane, substantially perpendicular to the longitudinal direction L.

[0131] The first and second electrodes 5, 7 extend longitudinally.

[0132] The heating plate 3 has a single winding path 63 for the electric current, comprising the first intermediate branch 31, the second intermediate branch 33, and all other intermediate branches 21 located between the first and second intermediate branches 31 and 33. In other words, the winding path 63 includes all the intermediate branches 21.

[0133] On the other hand, the two end branches 19 are not integrated into the sinuous path 63 in which the electric current flows.

[0134] The electrically conductive material has a first density in the intermediate branches 21, 31, 33.

[0135] In order to reduce the amount of electrically conductive material used to manufacture the heating plate 3, and to reduce the weight of the heating plate 3, it has a second density lower than the first density in the end branches 19.

[0136] Typically, the electrically conductive material has a higher pore density in the end branches 19, or larger pore sizes.

[0137] According to one embodiment, the electrically conductive material has a second density lower than the first throughout the peripheral edge 11.

[0138] According to another embodiment, the electrically conductive material has a second density lower than the first in the first and / or second distribution bars 55, 57.

[0139] The first and second distribution bars 55, 57 are connected to the junction elbows 29 between the end branches 19 and the first and second intermediate branches 31, 33. Advantageously, said elbows 29 have a second density lower than the first.

[0140] The heating plate 3 does not have a connecting bar on the distal side of the plate, i.e. opposite the electrodes 5, 7.

[0141] The heating device has multiple advantages.

[0142] When the first and second intermediate branches are close in alignment, the first and second electrodes can be arranged particularly close to each other. Connection to the electrical harness is facilitated.

[0143] When the first and second intermediate branches are located transversely at the center of the alignment, the path of the electric current is particularly simple to draw. The heating plate can be designed symmetrically.

[0144] Integrating the distribution bar connecting the first and second winding paths into the heating plate makes the heating device very compact. The distribution bar organizes the flow of electric current within the heating plate to achieve uniform heating.

[0145] When the distribution bar is made of a denser material than that constituting the first and second winding paths, the flow of electric current in the distribution bar does not create a hot spot.

[0146] In the second embodiment, the first and second electrodes are connected to the first and second intermediate branches by distribution bars. The first and second intermediate branches are close to the two end branches. These end branches are not integrated into the electric current path. Making the material electrically conductive less dense in the end branches allows the plate to be lighter and the cost of manufacturing the plate to be reduced.

[0147] Manufacturing the heating plate by additive manufacturing makes it possible to conveniently produce heating plates of complex shapes, for example of the type shown in Figures 1 and 2.

[0148] When the first and second electrodes are also obtained by additive manufacturing with the heating plate, the welding step of the first and second electrodes is eliminated. Furthermore, there is no discontinuity between the electrode and the plate that could create a hot spot. The risks of quality defects due to welding are eliminated.

[0149] The manufacturing process of the invention offers the advantage that, during the welding of the first electrode, the point of the first intermediate branch grounded is close to, and substantially in the longitudinal extension of, the area to be welded. As a result, the distribution of the electrical current lines during welding is very uniform in the first intermediate branch, which is favorable for weld quality.

[0150] The heating device could have multiple variants.

[0151] The first and second intermediate branches, to which the electrodes are connected, are not necessarily located at the center of the alignment. They could be located at intermediate points between the embodiment shown in [Fig. 1] and the embodiment shown in [Fig. 2]. It would then be necessary to redraw the first and second sinuous paths. The plate could, in particular, include a third sinuous path between the first and second sinuous paths. It would also include two distribution bars, one connecting the first sinuous path to the third sinuous path, and the other connecting the second sinuous path to the third sinuous path.

Claims

Demands

1. A heating device for a vehicle exhaust system, the heating device (1) comprising a heating plate (3) made of an electrically conductive material and first and second electrodes (5, 7) fixed to the heating plate (3), the heating plate (3) comprising a plurality of branches (19, 21) elongated along a longitudinal direction (L), the branches (19, 21) being juxtaposed along a transverse direction (T) and forming a transverse alignment having two end branches (19) located at the two transverse ends of the alignment and intermediate branches (21) arranged between the end branches (19), each branch (19, 21) having a proximal end (23) facing a first longitudinal side of the heating plate (3) and a distal end (25) facing a second longitudinal side of the heating plate (3) opposite to the first side, the branches (19,21) being separated from each other by longitudinal slits (27), each opening at at least one longitudinal end, the proximal end (23) and / or the distal end (25) of each branch (19, 21) being connected respectively to the proximal end (23) and / or the distal end (25) of a neighboring branch (19, 21) in alignment; the first and second electrodes (5, 7) being connected to the proximal ends (23) of a first of the intermediate branches (31) and a second of the intermediate branches (33) respectively; the heating plate (3) comprising: - a first winding path (35) for the electric current, comprising the first intermediate branch (31), a last branch and all the branches (21) located in the alignment between the first intermediate branch (31) and the last branch, the last branch being either one of the end branches (19) or the intermediate branch (21) adjacent to the end branch (19) in the alignment; - a second winding path (37) for the electric current, comprising a plurality of branches (19, 21) close together in alignment; - a distribution bar (39), connecting the distal end (25) of the last branch of the first winding path (35) to the distal end (25) of one of the branches (19, 21) of the second winding path (37).

2. Heating device for a vehicle exhaust system, the heating device (1) comprising a heating plate (3) in one

3.

4. electrically conductive material and first and second electrodes (5, 7) fixed to the heating plate (3), the heating plate (3) comprising a plurality of branches (19, 21) elongated along a longitudinal direction (L), the branches (19, 21) being juxtaposed along a transverse direction (T) and forming a transverse alignment having two end branches (19) located at the two transverse ends of the alignment and intermediate branches (21) arranged between the end branches (19), each branch (19, 21) having a proximal end (23) turned towards a first longitudinal side of the heating plate (3) and a distal end (25) turned towards a second longitudinal side of the heating plate (3) opposite to the first side, the branches (19, 21) being separated from each other by longitudinal slots (27) each opening at at least one longitudinal end,the proximal end (23) and / or the distal end (25) of each branch (19, 21) being connected respectively to the proximal end (23) and / or the distal end (25) of a neighboring branch (19, 21) in alignment; the first and second electrodes (5, 7) being connected to the proximal ends (23) of a first of the intermediate branches (31) and a second of the intermediate branches (33) respectively; the first intermediate branch (31) being close in alignment to one of the first of the two end branches (19), the second intermediate branch (33) being close in alignment to one of the second of the two end branches (19), the heating plate (3) having a first distribution bar (55) connecting the first electrode (5) to the proximal end (23) of the first intermediate branch (31) and / or a second distribution bar (57) connecting the second electrode (7) to the proximal end (23) of the second intermediate branch (33), the electrically conductive material having a first density in the intermediate branches (21), the electrically conductive material having a second density lower than the first in the end branches (19). Heating device according to claim 1 or 2, wherein the first and second intermediate branches (31, 33) are adjacent in alignment. Heating device according to any one of the preceding claims, wherein the first and second intermediate branches (31, 33) are located transversely to the center of the alignment.

5. Heating device according to claim 1, wherein the first and second sinuous path (35, 37) are made of a relatively less resistive electrical material and the distribution bar (39) is made of a relatively more resistive electrical material.

6. Heating device according to any one of the preceding claims, wherein the heating plate (3) is obtained by additive manufacturing.

7. Heating device according to any one of the preceding claims, wherein the first and second electrodes (5, 7) are obtained by additive manufacturing with the heating plate (3).

8. A heating device according to any one of the preceding claims, wherein the heating device (1) comprises an annular housing (13) internally delimiting a void (14), the first electrode (5) being directly connected to a terminal section (42) of the first intermediate branch (31) housed in the annular housing (13), the first intermediate branch (31) having a central section (43) passing through the void (14) and having a given central longitudinal length, said terminal section (42) housed in the housing (13) having a length less than 20% of said central longitudinal length.

9. A method for manufacturing a heating device according to claim 8, the method comprising the following successive steps: - obtaining the heating plate (3) and the first and second electrodes (5, 7); - inserting an edge (11) of the heating plate (3) into an annular housing (13); - welding the first electrode (5) to the proximal end (23) of the first intermediate branch (31), a point (51) of said first intermediate branch (31) being electrically connected to ground during welding.