Electric heater device particularly having PTC effect

Abstract

An electric heater device includes at least one heating element (10), and at least one heating element (10) includes a first electrode (121), a second electrode (122), and a heating body (11). The heating body (11) is made of a polymer-based material (11a) with PTC effect that contacts the first electrode (121) and the second electrode (122). At least one of the first electrode (121) and the second electrode (122) includes a mesh structure (13), the mesh structure (13) extends in the length direction (L) and the width direction (W), and is at least partially embedded in the heating body (11). At least one of the first electrode (121) and the second electrode (122) further includes at least one electrical distribution element (14), which preferably includes a formed strip or foil of conductive material. The at least one electrical distribution element (14) is fixed to the mesh structure (13), and includes at least one distribution portion that extends in at least one of the length direction (L) and the width direction (W) of the mesh structure (13).

Description

Technical Field

[0001] The present invention relates to an electric heater device, in particular to a device based on the use of a material characterized by a resistance with a positive temperature coefficient (i.e., a material with a PTC effect, preferably of the polymer type, i.e., a polymer-based material or a material comprising at least one polymer).

[0002] The present invention has been developed in particular with reference to an electric heater device associated with or integrated in a vehicle component, such as a heater for a tank or reservoir, a heater for a filter, a heater for a fluid conduit, a heater for a battery, a heater for a substance that is prone to freezing or whose properties vary with temperature, or again a heater for heating a gaseous substance (such as air for the environment or air that undergoes forced circulation on the surface of the aforementioned heater).

[0003] The present invention is preferably applied in the field of components of a tank or conduit in contact with a liquid (e.g., a liquid necessary for the operation of an internal combustion engine or for the treatment or reduction of the exhaust of an internal combustion engine, including a water injection or anti-knock injection system). The heater device according to the present invention can also be applied in any case to a context different from the preferred context mentioned above. Background Art

[0004] The preamble of claim 1 is based on WO 2017 / 077447 A, which discloses an electric heater device of the type mentioned, comprising a plurality of heating elements integrated in a component of a motor vehicle tank. Each heating element comprises a heating body made of a polymer material with a PTC effect, which is arranged between and in contact with two parallel electrodes. The electrodes are in the form of metal foils, substantially identical to each other, and may be provided with holes, and substantially coat two opposite main faces of the heating body, which has the shape of a substantially parallelepiped layer.

[0005] From the perspective of heat dissipation, this type of heating element structure is efficient, due to the fact that the wide parallel surfaces of the layered electrodes almost completely coat the opposite surfaces of the block of material with a PTC effect: in this way, the uniformity and intensity of the current between the electrodes themselves and thus a good heating power are ensured.

[0006] However, it has been found that, especially in the long term, due to the cycles of heating and cooling, the heater device can be affected by problems related to the deformation (e.g., expansion and contraction) of the material with PTC effect and / or the corresponding metal electrodes. Such deformation can lead to relative movement between components made of different materials, with the possible risk of delamination or peeling of the electrodes from the corresponding surfaces of the heating body made of the material with PTC effect, and the consequent decay of the operating characteristics of the device. Summary of the Invention

[0007] In view of what has been set forth above, the basic object of the present invention is to overcome or at least limit the aforementioned drawbacks of the prior art by means of an electric heater device constructed in a generally simple, inexpensive and reliable manner. According to the present invention, the above object and further other objects are achieved by an electric heater device, a motor vehicle component and a method for obtaining an electric heater device having the features specified in the appended claims, which objects will become apparent hereinafter. The claims form part of the technical teaching provided herein with respect to the present invention. Brief Description of the Drawings

[0008] With reference to the accompanying drawings, the features, advantages and further objects of the present invention will become apparent from the following detailed description, which is provided by way of non-limiting example only, and in which:

[0009] - Figure 1 is a schematic perspective view of a heater device according to a possible embodiment of the present invention;

[0010] - Figure 2 is a partial exploded schematic view of a heater device according to a possible embodiment of the present invention;

[0011] - Figure 3 is an exploded schematic view of a heating element according to a possible embodiment of the present invention;

[0012] - Figure 4 is a schematic perspective view of a heating element according to a possible embodiment of the present invention;

[0013] - Figure 5 is a schematic perspective view of an electrode of a heater device according to a possible embodiment of the present invention;

[0014] - Figure 6 schematically represents, via a perspective view, a possible alternative configuration of the components of an electrode of a heater device according to a possible embodiment of the present invention;

[0015] - Figure 7 is a schematic representation of the process for fixing two components of an electrode of a heater device according to a possible embodiment of the present invention;

[0016] - Figure 8 is Figure 5 a more detailed view on a larger scale of

[0017] - Figure 9 is Figure 8 a more detailed view on a larger scale of

[0018] - Figure 10 is a view similar to the view of Figure 9 for a variant embodiment of the present invention;

[0019] - Figure 11 is a schematic perspective view of a motor vehicle component of an integrated heater device according to a possible embodiment of the present invention;

[0020] - Figure 12 is Figure 11 a partial exploded schematic view of two components of the component of

[0021] - Figure 13 is a schematic representation of a first process for obtaining a housing body of a heater device according to a possible embodiment of the present invention;

[0022] - Figure 14 and Figure 15 is a schematic representation of a second process for obtaining a housing body of a heater device according to a possible embodiment of the present invention;

[0023] - Figure 16 is a schematic perspective view of a plurality of heating elements of a heater device according to a possible embodiment of the present invention;

[0024] - Figure 17 is an exploded schematic view of an electrode of a heater device according to a possible embodiment of the present invention;

[0025] - Figure 18 and Figure 19 is a schematic representation of a first process for obtaining a heating element according to a possible embodiment of the present invention;

[0026] - Figure 20 is Figures 18 to 19 a schematic perspective view of a heating element obtainable by the process of

[0027] - Figure 21 is a schematic representation of a second process for obtaining a heating element according to a possible embodiment of the present invention;

[0028] - Figure 22 is Figure 21 a schematic perspective view of a semi-finished product used in the process of

[0029] -Figure 23 and Figure 24 is Figure 21 a further schematic representation of the process;

[0030] - Figure 25 is a schematic partial cross-section of a heating element according to a possible embodiment of the present invention;

[0031] - Figure 26 and Figure 27 are respectively a schematic perspective view and an exploded view of a further heating element according to a possible embodiment of the present invention;

[0032] - Figure 28 and Figure 29 are respectively a schematic perspective view and an exploded view of a further heating element according to a possible embodiment of the present invention;

[0033] - Figure 30 and Figure 31 are respectively a schematic perspective view and an exploded view of an electrode of a heater device according to a possible embodiment of the present invention;

[0034] - Figure 32 is a partial exploded view of a motor vehicle component integrating at least one heater device according to a possible embodiment of the present invention; and

[0035] - Figure 33 is a view similar to Figure 32 wherein the heating element of the heater device is shown in an exploded view. DETAILED DESCRIPTION

[0036] References to "an embodiment" or "one embodiment" within the framework of this description are intended to indicate that the particular construction, structure, or characteristic described with respect to that embodiment is included in at least one embodiment. Thus, phrases such as "in an embodiment" or "in one embodiment" that may occur at various points in this description do not necessarily refer to the same embodiment. Furthermore, the particular conformations, structures, or characteristics defined within this description may be combined in any suitable manner in one or more embodiments (even those different from the ones presented). The reference numbers and spatial references (such as "upper", "lower", "top", "bottom", etc.) used herein are provided for convenience only and thus do not delimit the scope of protection or the scope of the embodiments. In this description and the appended claims, the general term "material" will be understood to include mixtures, compositions, or combinations of a variety of different materials (e.g., multi-layer structures). In this description and the appended claims, the term "mesh structure" or "net structure" is understood to indicate a structure formed by the crossing or interweaving of substantially filamentous elements (preferably wires or threads), such as a net, grid, weave, etc.

[0037] First, referring to Figure 1 , the heater device as a whole designated by 1 is a possible embodiment according to the present invention. Hereinafter, it will be assumed that the device 1 belongs to a system installed in a motor vehicle, such as a system for heating an air stream or for heating a liquid contained in a tank or reservoir or flowing through a conduit.

[0038] The device 1 includes a housing body 2 that at least partially encloses Figure 2 at least one heating element designated as a whole by 10 therein. The housing body 2 is preferably provided with an electrical connector 3 for connection to an electrical power source.

[0039] In various embodiments, the housing body of the heater device according to the present invention is composed of two or more components fixed to each other, while in other embodiments, the housing body is at least partially formed by overmolding a material onto at least one heating element of the device. The housing body can be of a sealed type, i.e., designed to enclose one or more heating elements of the device in a fluid-tight manner.

[0040] In various embodiments, the heater device forming the subject matter of the present invention is configured as an independent component. In this case, its housing body is preferably configured for installation and / or fixation in a more complex system (such as a heating system of a motor vehicle). In other embodiments, the device forming the subject matter of the present invention is instead integrated into a component that is pre-arranged to perform functions other than heating a general medium. In this case, at least part of the body of the component can also be used to at least partially provide the housing body of the heater device. In still other applications, the device does not require its own housing body (for example, when the corresponding heating element is directly exposed to a given environment for heating that environment).

[0041] In Figure 1 and Figure 2 illustrated cases, the device 1 is configured as an independent component, and its housing body 2 is composed of three components 2 1 , 2 2 and 2 3 made of, for example, an electrically insulating thermoplastic material, which can preferably be fixed to each other in a sealed manner, such as by gluing or welding or hooking, so as to enclose at least part of the heating element 10 therein.

[0042] Referring again to Figure 1 and Figure 2 illustrated cases, the housing component designated by 2 1 has a substantially box-shaped structure that defines a seat 4 for completely or mostly accommodating the heating element 10 inside it. In the illustrated case, the housing component 2 1It has a flange-shaped front part 5, which is provided with a slit 5a through which the element 10 can be inserted into the seat 4 in the transverse direction, such that two electrical connection terminals 12a of the corresponding electrodes belonging to or connected to the heating element 10 (only one of which is Figure 2 visible in the 1 and is denoted by 12 2 project beyond the part 5 at the front. The housing part denoted by 2 Figure 1 is fixed to the front part 5 at the front, and this housing part defines a connector body 6 which is configured to receive the terminals 12a therein and thus provides Figure 1 the connector 3. In the illustrated example, the housing part 2 2 further includes a flange-shaped part 7 which is designed to close the slit 5a.

[0043] In the example, the seat 4 can be closed via the housing part denoted by 2 3 which substantially serves as a cover for the aforementioned seat and is fixed peripherally to the housing part 2 1 .

[0044] Figure 3 A possible embodiment of the heating element 10 is illustrated in the exploded view in . In this figure, the heating body of the element 10 is denoted by 11, which is at least partially made of a material having a PTC effect (i.e., a material characterized by a positive temperature coefficient of resistance) and is arranged to contact two electrodes represented integrally by 12 1 and 12 2 .

[0045] In a preferred embodiment, the material 11a constituting the body 11 is a polymer-based material (i.e., a material comprising at least one polymer), preferably a composite material having a matrix formed by a polymer or a mixture of polymers and corresponding fillers (such as conductive fillers and / or thermal fillers).

[0046] In various preferred embodiments, the material 11a of the heating body 11 is a co-continuous polymer composite material having a PTC effect, which has a matrix comprising at least two immiscible polymers and at least one conductive filler in the matrix. In this type of preferred embodiment, at least one of the immiscible polymers is high-density polyethylene (HDPE), and at least another of the immiscible polymers is polyoxymethylene (POM). The conductive filler preferably consists of particles having a micron or nano size (preferably included between 10 nm and 20 μm, very preferably between 50 nm and 200 nm), and the particles may aggregate to form chains or branched aggregates having a size between 1 μm and 20 μm. The preferred material for the conductive filler is a carbon material, such as carbon black or graphene or carbon nanotubes or a mixture thereof.

[0047] The relative percentages of HDPE and POM are preferably between 45% and 55% of their total weight. Preferably, the conductive filler is restricted or mainly restricted in HDPE, at a weight percentage between 10% and 45%, preferably between 16% and 30%, of the total weight of HDPE and the conductive filler. For this purpose, HDPE and the conductive filler can be particularly mixed together via extrusion before subsequent mixing with POM, and the mixing with POM can also preferably be carried out via extrusion in this case.

[0048] The high melting point of POM makes it possible for the two phases of HDPE and POM to be better separated, thus reducing the possibility of the conductive filler migrating into POM (contributing to this effect is the fact that the filler is preferably pre-mixed only with HDPE). Compared with other known polymers, the higher melting point of POM also makes it possible to obtain a more stable final structure: the PTC effect of the composite material limits the self-heating to a maximum temperature of approximately 120 °C. In addition, POM exhibits a high crystallinity indicatively between 70% and 80%: this means that in the proposed preferentially co-continuous composite material, the migration of the filler from HDPE to POM is less likely to occur, thus preventing the loss of the performance of the material with PTC effect due to, for example, heating and current passing. The higher crystallinity of POM also makes the composite material particularly durable from a chemical point of view and imparts high stability to it. On the other hand, the crystallinity of HDPE typically ranges between 60% and 90%: in this way, a high concentration of conductive filler in the amorphous domains is obtained, which has a corresponding high electrical conductivity.

[0049] For example, with reference to Figure 3 , according to an aspect of the present invention, electrode 12 1 and 12 2 at least one of them includes a mesh structure or net structure represented by 13, which is at least partially embedded or enclosed in the heating body 11 (i.e., in the material 11a constituting the heating body).

[0050] As will become clearer hereinafter, at least partial embedding of the mesh structure 13 can be obtained by penetrating the structure 13 into the heating body 11 at one side of the heating body 11 via mechanical pressure and / or heating, or by overmolding at least part of the heating body 11 onto the mesh structure 13 or the corresponding electrode 12.

[0051] In this regard, it should be noted that in Figure 2 , for reasons of greater clarity, belonging to electrode 12 1The mesh structure 13 is almost entirely shown in the view, i.e., as if it were resting on the heating body 11. However, as described above, in various preferred embodiments of the present invention, the aforementioned structure 13 is at least partially embedded in the material 11a of the body 11, preferably such that there are portions of the material 11a between the openings defined between the various meshes of the structure. On the other hand, it is also possible to embed the mesh structure 13 of the electrodes almost entirely in the material 11a, for example, as Figure 4 schematically represented in

[0052] Preferably, the mesh structure 13 extends substantially parallel to the main face of the heating body 11, and the aforementioned structure 13 defines a region that substantially corresponds to the region of the main face of the body 11, or in any case corresponds to the region of the main components of the body 11. In this way, the heating body 11 is disposed between the wide surfaces of the structures 13 of the two electrodes 12 1 and 12 2 to ensure good uniformity and good intensity of the power current passing between the electrodes themselves.

[0053] The mesh structure 13 thus extends in the length direction L and the width direction W, and is preferably substantially two-dimensional, i.e., having a minimum thickness, substantially like a sheet structure.

[0054] In various preferred embodiments, the structure 13 is constituted by a fabric formed at least in part by wires of a conductive material (preferably a metallic material). Preferred metals are, for example, selected from stainless steel, copper, aluminum, brass, bronze, nickel-chromium-based alloys, or iron-chromium-based alloys. The conductive fabric can be obtained by interlacing or crossing the wires using any known technique; for example, the type of weave can be selected from the following:

[0055] - Plain weave, in which each weft thread passes alternately above and below each warp thread, and vice versa;

[0056] - Twill weave, in which each weft thread alternately crosses two warp threads;

[0057] - Dutch plain weave, in which the warp threads have a diameter greater than that of the weft threads, and the weave is constituted by a small number of warp threads interlaced with a large number of weft threads;

[0058] - Dutch twill weave, which can be obtained by a weave similar to the Dutch plain weave, except that the weave is a twill weave and has a double layer of weft threads;

[0059] - Reverse Dutch weave, which is substantially the opposite of the Dutch plain weave, i.e., there are more thinner threads in the warp and fewer thicker threads in the weft; and

[0060] - Reverse Dutch twill weave, which is a weave similar to the previous one, but in which each weft thread alternates with two warp threads in crossing.

[0061] Preferably, for reasons clarified below, the wires providing the conductive fabric have a reduced nominal diameter indicatively between 0.2 mm and 0.02 mm (i.e., before weaving). The mesh openings of the fabric (i.e., the space between two adjacent and parallel wires of the structure) preferably comprise between 1 mm and 0.05 mm.

[0062] It should be noted that in Figure 3 and Figure 5 the mesh structure 13 is represented in a partial and schematic form so as to highlight in particular in Figure 5 the crossing or interweaving of the weft and warp threads respectively represented by 16a and 16b.

[0063] The fact that the mesh structure 13 is at least partially embedded in the material 11a having a PTC effect prevents the risk of the corresponding electrode 12 detaching or peeling off from the heating body 11, which is a typical problem of the prior art (even in the case where there may be deformations of the material 11 and / or the structure 13 due to heating and cooling cycles). The fact that the mesh structure 13 is relatively dense and extensive in any case ensures a considerable distribution and intensity of the current between the electrodes 12.

[0064] As can be appreciated, the peripheral contour of the mesh structure 13 of the electrode 12 can be easily obtained, for example, via the basic operations of cutting or punching of a conductive sheet or web of fabric or mesh. The aforementioned peripheral contour does not necessarily have to be quadrilateral as illustrated so far in the figures.

[0065] According to another aspect of the present invention, in addition to the mesh structure 13, at least one electrode 12 1 or 12 2 also comprises at least one electrical distribution element, such as Figure 2 and Figure 3 the electrical distribution element represented by 14 in

[0066] Element 14 is shaped so as to distribute the current over the wires 16a, 16b or similar filamentary elements forming the reticular structure 13, in particular so as to prevent an undesired concentration of current on a few wires, which concentration could even cause the melting of the wires themselves. For this purpose, in various embodiments, the distribution element 14 has at least one portion extending substantially throughout the entire width W and / or at least one portion extending substantially throughout the entire length L of the structure 13. However, at least one portion of the distribution element may also extend only partially through the width W and / or the length L of the structure 13, preferably extending through at least half or one third of the width W and / or the length L of the structure 13.

[0067] The electrical distribution element 14 is preferably fixed to the face of the reticular structure 13 opposite to the body 11 so as not to prevent the structure itself from being embedded in the material 11a having a PTC effect. The electrical distribution element 14 may also be fixed to the face of the reticular structure 13 facing the body 11, and in this case, portions of the distribution element 14 may also be embedded in the structure of the material 11a having a PTC effect.

[0068] To further improve the distribution of the current, in various preferred embodiments, at least one portion of the electrical distribution element 14 extends substantially at or near the edge of the reticular structure 13.

[0069] For example, referring to Figures 3 to 5 , it can be noted how the represented element 14 has at least one portion 14a extending in a direction transverse to the structure 13 (i.e., in the direction W) and at least one portion 14b extending in a direction longitudinal with respect to the structure 13 (i.e., in the direction L), where these two portions are preferably substantially at right angles to each other (however, different angles are possible). In various embodiments (such as the represented embodiment), furthermore, branching from the portion 14a are additional portions 14c, which extend in the longitudinal direction L, preferably substantially parallel to the portion 14b, and are preferably distributed substantially in the transverse direction W.

[0070] Thus, the electrical distribution element may have a substantially comb-like conformation, with teeth or fingers of different lengths (as in the case of the foregoing Figures 3 to 5 ) or teeth or fingers of the same length. In any case, as can be seen, the area of overlap between the distribution element or all of its distribution portions and the corresponding reticular structure is less than the area of that reticular structure; in particular, as shown in the figure, the overlap area is significantly less than the area of the corresponding reticular structure, preferably the overlap area is at least less than half or one third of the area of the corresponding reticular structure.

[0071] In a number of preferred embodiments, the electrical distribution element 14 has at least one electrical connection portion which, when the device is in the assembled condition, is designed to project beyond the peripheral edge of the mesh structure 13 or the heating body 11 so as to be accessible for the purpose of electrical connection. In the case illustrated, the aforementioned projection is designated by 12a in the figure, provided that it corresponds to the terminal mentioned previously. Advantageously, then, the electrical distribution element may directly define the electrical connection terminal 12a of the corresponding electrode 12.

[0072] From Figure 6 It can also be deduced how the total area of the distribution portion 14a or the distribution portions 14a - 14b, 14a - 14c of the element 14, which are designed to overlap with the corresponding mesh structure, amounts to a limited portion of the area of the mesh structure. By way of example only, with reference to Figure 6 cases a), b), c), d) of part, the overlapping area can be less than 10%, less than 20%, less than 30% or less than 50% of the area of the corresponding mesh structure, respectively.

[0073] In a number of embodiments, the distribution element 14 is shaped so as to be connected to a significant or major portion of the wires 16a and / or 16b providing the mesh structure 13, preferably where at least one transverse portion (such as portion 14a) is connected to at least one third or at least one half of the wire 16a, and / or where at least one longitudinal portion (such as portion 14b) is connected to at least one third or at least one half of the wire 16b.

[0074] In a number of embodiments, the distribution element 14 is shaped so as to be connected to a plurality of wires 16a and / or 16b such that the sum of the cross - sections of these wires allows the current circulation necessary for the operation of the device 1 and / or the heating element 10 without any damage or abnormality.

[0075] In Figure 6 are represented by way of example only some possible configurations of the electrical distribution element 14 which can be used in a heater device according to the invention. The illustrated configurations are not of an exhaustive nature, since an infinite number of configurations suitable for the purpose are possible.

[0076] In Figure 6 part A) of is illustrated a simpler shape of the element 14 which has a distribution portion 14a extending in the direction of the width W of the mesh structure 13 (or, obviously, in the direction of the length L of the aforementioned structure) and a portion constituting the terminal 12a (here generally orthogonal to the portion 14a).

[0077] In Figure 6Shown in part B) thereof is an element 14 that is mainly L-shaped, i.e., an element including both a distribution part 14a that will extend in the width direction (or length direction) of the structure 13 and a distribution part 14b that will extend in the length direction (or correspondingly, width direction) of the same structure 13; also in this case, extending from one of the two aforementioned parts 14a and 14b that are substantially orthogonal to each other (here it is part 14a) is a connecting part that constitutes the terminal 12a.

[0078] In Figure 6 Shown in part C) thereof is an element 14 having a substantially comb-like shape, i.e., an element including both a distribution part 14a that will extend in the width (or length) direction of the structure 13 and two distribution parts 14b and 14c, the distribution parts 14b and 14c being substantially parallel to each other and having the same length, and will extend in the length (or correspondingly, width) direction of the same structure 13; in this case, extending from part 14a is a connecting part that constitutes the terminal 12a.

[0079] In Figure 6 Shown in part D) thereof is an element 14 that also has a substantially comb-like shape, but has a series of teeth or fingers that are substantially parallel but of different lengths. In this example, provided are a distribution part 14a that will extend in the width (or length) direction of the structure 13 and four pairs of fingers 14b, 14c 1 、14c 2 and 14c 3 both, where, for example, the fingers in each pair are substantially of the same length, but the length is different from that of the fingers in other pairs, and each finger in one pair is disposed between two fingers in the other two different pairs; also in this case, extending from part 14a is a connecting part that constitutes the terminal 12a.

[0080] In a plurality of preferred embodiments, the electrical distribution element 14 is formed of a strip or foil of a conductive material. Thus, preferably, the distribution element 14 is also substantially two-dimensional, i.e., it has a very small thickness, preferably between 0.02 mm and 1.5 mm.

[0081] The strip constituting the element 14 is preferably made of a metal material that is compatible with the material of the mesh structure 13 (especially considering compatibility for welding between the structure 13 and the element 14); from this perspective, for example, the metal material constituting the aforementioned strip can be selected, for example, from: stainless steel, copper, aluminum, brass, bronze, nickel-chromium-based alloys, or iron-chromium-based alloys.

[0082] The strip forming the component 14 may be at least partially coated with a different material, preferably a second conductive material and / or a protective material. From this perspective, the terminal 12a may be at least partially coated with tin, for example to facilitate the soldering of a wire, or at least partially coated with gold or some other precious metal, for example to improve the electrical contact with the terminal of an external connector; at least the external part of the strip that does not come into contact with the mesh structure may also be coated with a protective and / or electrically insulating material.

[0083] It will be apparent that the peripheral profile of the distribution element 14 of the electrode 12 can also be easily obtained, for example, via basic operations of blanking or punching (and possible deformation) of a sheet or strip of conductive metal.

[0084] In a preferred embodiment, the mechanical connection or fixation between the mesh structure 13 of the electrode 12 and the corresponding electrical distribution element 14 is obtained via welding (preferably welding without adding welding material).

[0085] In various preferred embodiments, the welding operation performed between the two components under discussion is resistance welding, that is, a method of autogenous pressure welding by resistance heating of the material. Figure 7 Such a technique is illustrated, where E1 and E2 represent the two metal electrodes of the welding equipment.

[0086] In Figure 7 Part A) schematically shows the initial situation, where the two welding electrodes E1 and E2 are at a first distance from each other, which enables the insertion between them of the structures 13 and 14 simply stacked on top of each other. Instead, Figure 7 Part B) of illustrates the subsequent step, where the two welding electrodes E1 and E2 are brought closer to each other in order to mechanically press the structure 13 against the surface of the element 14 that comes into contact with the structure 13 itself, that is, at the corresponding overlapping area. While applying mechanical pressure, a current is made to flow between the electrodes E1 and E2, the intensity of which is such that heat is generated by the Joule effect, which is sufficient to cause partial melting of the wires 16a, 16b and / or the strip of the element 14, and thus to weld them together (the heat generated in the areas of the aforementioned wires and strip will be substantially proportional to the current intensity and the resistance of the parts to be joined). Figure 7 Part C) of shows the subsequent step, where the welding electrodes E1 and E2 are moved away from each other in order to enable the removal of the electrode 12 1 , where the structures 13 and 14 are now welded together.

[0087] The welding of the distribution element 14 onto the mesh structure 13 typically also causes the deformation of the wires of the aforementioned structure. However, this deformation is basically limited to the overlapping area between the element 14 and the structure 13. Referring to the welding techniques illustrated above, the degree of wire deformation at the overlapping welding area will basically vary with the generated welding heat and / or the mechanical pressure between the components. From Figure 5 and in particular from Figure 8 the corresponding details, it can be noted how the shape of the wires of the mesh structure 13 at the welding area 17a is different from the shape of the wires in the non-overlapping area 17b not involved in the welding process. From Figure 9 the further details shown in, it can be better recognized that the wires 16a, 16b have different shapes at the welding area 17a and in the area 17b not involved in the welding process. At the welding area 17a, the aforementioned wires are extruded and partially melted, and at the area 17b, the wires basically maintain their initial nominal diameter and / or shape.

[0088] Via a view similar to Figure 9 the view, Figure 10 the case of performing a stronger welding between the structure 13 and the element 14 is illustrated, that is, where more heat is generated and / or higher mechanical pressure is applied at the area 17a to be welded, and thus more significant melting and / or deformation of the wires 16a, 16b is caused, and the wires 16a, 16b form a basically flat grid in these areas 17a.

[0089] In various embodiments (such as the embodiments illustrated so far), the electrodes 12 1 and 12 2 each include at least one corresponding mesh structure 13 and at least one corresponding electrical distribution element 14. The two electrodes are preferably substantially identical to each other, which is beneficial to the standardization of production. The electrodes 12 1 and 12 2 can be integrated into the heating body 11 at opposite sides of the body 11 (preferably opposite main faces substantially parallel to each other) so as to generate a current circulation in a plane perpendicular to the aforementioned faces (i.e., through the thickness of the body 11). However, according to other embodiments, the electrodes can be located on the same face of the body 11. In addition, as described above, it is preferred that the electrodes 12 1 and 12 2 or at least the corresponding mesh structures 13 extend substantially parallel to the corresponding faces of the body 11.

[0090] When the two electrodes 12 1 and 12 2The distribution element 14 has corresponding electrical connection portions 12a (so that the electrical connection portions 12a can be arranged in positions close to each other to provide an electrical connector such as the connector 3), and such an arrangement of the above type is particularly advantageous.

[0091] Thus, in various embodiments, at least a part of the heating body 11 (preferably a part having a substantially constant thickness) is disposed between the two electrodes 12 1 and 12 2 The body 11 may have a peripheral dimension substantially similar to that of the electrode or its structure 13, but it is not excluded that a part of the body 11 protrudes beyond the edge of the structure 13 or is recessed relative to the edge of the structure 13.

[0092] Returning to Figures 2 to 3 , in the illustrated case, the heating body 11 is preferably at least partially overmolded on the electrodes 12 1 and 12 2 The two electrodes in question are inserted into a mold, and the polymer material 11a having a PTC effect is injected into the mold in a molten state. To facilitate the aforementioned production steps, especially during the injection of the polymer and / or during the previous treatment of the semi-finished product, a spacer body and / or a positioning body may be interposed between the two electrodes, and the spacer body and / or the positioning body are particularly configured to ensure proper relative positioning of the electrodes (especially in the mold).

[0093] In Figure 3 an example of a possible embodiment of such a spacer body represented by 15 is illustrated, which may be made of an electrically insulating material or may itself be made of a material having a resistance or a PTC effect, for example, the material is also a polymer-based material. In this example, the spacer body 15 is substantially shaped to define a reticular framework having a peripheral frame 15a, and extending within the peripheral frame 15a are a series of longitudinal elements 15b and a series of transverse elements 15c that are preferably coplanar with each other. In the case where the height (thickness) of the elements 15b and 15c is less than the height (thickness) of the frame 15a, it is possible to provide bosses 15d at the intersection regions between the aforementioned elements 15b and 15c to compensate for the height difference. Some of the bosses 15d may also be shaped as engaging devices so as to engage with at least one electrode 12 1 and / or 12 2 for example, in an opening of the structure 13.

[0094] In this example, the outer side of the peripheral frame 15a of the spacer body 15 is designed not to be coated with the material 11a of the heating body 11 so as to constitute at least a part of the peripheral edge of the heating element 10 (see this point in Figure 2). It will be appreciated that in any case the spacer body can also be completely embedded in the overmolding material 11a, as for example in Figure 4 In the case of , the mesh structure of the electrodes is also completely embedded in the material 11a of the heating body 11. Furthermore, it will be appreciated that the shape of the spacer body used may differ from that illustrated, as long as the function of the spacer body remains the same.

[0095] The heater device according to the invention may comprise a plurality of heating elements and / or, as already mentioned, may be integrated in a component which also performs a function different from or in addition to the heating of the general medium.

[0096] Figures 11 to 25 1 and 2 are various embodiments suitable for implementing the two aforementioned features. These figures illustrate how in various embodiments the heater device or its heating element can have a generally arcuate shape, which differs from the previously illustrated embodiments in which the device 1 and the heating element 10 are generally straight or planar. Even only a single portion of the heating element (the heating body or its electrode) can be at least partially planar, or at least partially arcuate, or partially planar and partially arcuate.

[0097] Special reference Figure 11 , indicated as a whole by 30, is a motor vehicle component, and in particular a component for containing a tank for a generally liquid substance. For example, component 30 may form part of a system of the type known as water injection or anti-detonation injection (ADI), in which case the liquid in question is water to be injected into the cylinders of an internal combustion engine. Alternatively, component 30 may form part of a so-called selective catalytic reduction (SCR) system, in which case the liquid in question is an aqueous solution containing urea to be injected into the exhaust line in order to reduce nitrogen oxides.

[0098] On the other hand, as mentioned in the introduction to the present description, the component 30 may be of some other type, such as a component for accommodating or mounting a fuel filter of an internal combustion engine.

[0099] In the illustrated case, the member has a substantially cup-shaped body, in which a substantially tubular upper part, indicated by 1', can be identified (insofar as it is substantially provided by the heater device according to the invention) and a lower base 31 with a lower box-shaped part 32 provided with an inlet 33 and an outlet 34 for the liquid and preferably with an electrical connector 3'. However, the upper part 1' may also have some other shape, possibly provided with an opening, for example consisting of a plurality of arched walls arranged at a distance from each other, so as to provide at least one intermediate opening.

[0100] The box-shaped part 32 is preferably provided with a lower cover (not shown) so that functional elements (such as circuit components) can be positioned inside it. In this example, the body of the base 31 also has a flange portion denoted by 35, which can also be used to fix the member 30 to some other part of the vehicle, such as fixing or welding the member 30 to a tank.

[0101] The illustrated member 30 also integrates additional functional members, such as a sensor such as a liquid level sensor generally denoted by LS, which in any case constitutes an optional element of the member 30; for this purpose, the device 1' and / or the base 31 can be appropriately shaped and / or provided with at least one opening or seat for accommodating the aforementioned additional functional members.

[0102] As can be appreciated, after the device 1' is connected to the base 31 in a sealed manner, the body of the member 30 as a whole is formed, which delimits a volume (denoted by T in Figure 11 ), which is designed to accommodate liquid or, in any case, is designed to delimit an internal area where the liquid can be more easily heated.

[0103] Figure 12 is a partial exploded view of a member 30 of the following type: where the heater device 1' and the base 31 are constructed as separate components and fixed together in a sealed manner. As can be noted, the heater device 1' has its own housing body denoted by 2', which has a substantially tubular shape and can be made, for example, of an electrically insulating material (such as a polymer material) overmolded on a plurality of heating elements, as will be clarified below. As can be noted, protruding from the housing body 2' (here at its lower edge) are the terminals 12a for the electrical connection of the heater device, which will be electrically connected to the circuit present in the base 31, and the base 31 includes the corresponding terminals (not shown) of the connector 3'. In the figure, only two terminals 12a are shown, but the device 1 can include more than two terminals, as illustrated below.

[0104] Once again, from Figure 12 it can be noted how in this example an inlet port 33a and an outlet port 34a for the liquid are defined above the base 31, which are in fluid communication with the inlet 33 and the outlet 34 respectively. In addition, Figure 12 illustrated in Figure 11 is a seat 36 for positioning and electrically connecting additional functional members such as the liquid level sensor LS, and it can also be noted how a substantially annular seat 35a is defined within the flange portion 35 of the base 31 for sealingly fixing the lower edge of the housing body 2' of the heater device 1'. The body of the base 31 can be obtained at least in part by molding a polymer material (such as the same material used for producing the housing body 2').

[0105] Figure 13 Illustrates Figures 11 to 12 Possible steps of overmolding the housing body 2' of the heater device 1'. In this example, the heater device is designed to integrate three heating elements 10 having a generally arched shape, and these three heating elements are preferably but not necessarily substantially identical to each other. In this example, the mold part represented by M1 has a base part (without any reference numeral), and rising from the base part is a shape 40 which is designed to define the inner peripheral surface of the housing body 2' of the heater device. In the aforementioned base part, a seat 41 is defined at a peripheral position relative to the shape 40, and the terminals 12a of the heating elements 10 can be inserted into the seat 41. The terminals 12a are positioned near each other on the mold part to form an arc. The mold part M2 defines a hollow cavity (not visible), and this cavity is designed to define Figures 11 to 12 The outer peripheral surface of the housing body 2' and its top edge.

[0106] As can be recognized, as in Figure 13 After positioning the heating elements 10 on the mold part M1, the two mold parts are closed with each other so as to define a volume of a hollow shape, and this volume of the hollow shape has a shape corresponding (complementary) to the shape of the housing body 2', and the polymeric material designed to form the aforementioned housing body is injected into the aforementioned hollow volume. After the time necessary for solidification and cooling, the mold parts M1 and M2 can be opened again, and the device 1' including the housing body 2' can be taken out, as represented in Figure 12 In.

[0107] As an alternative to what has been illustrated with reference to Figure 12 And Figure 13 The base 31 of the heater device 1' and at least part of the housing 2' can also be constructed as a single piece, in particular a single piece obtained by overmolding the necessary polymeric material on the heating elements 10. In Figure 14 And Figure 15 Such a situation is schematically illustrated, in which two corresponding mold parts are represented by M3 and M4. In this case, the mold part M3 has a cavity 43 designed to define the outer contour of the base 31 and the part of its inner contour (as already mentioned, the base 31 can have a lower opening which will be closed by a subsequently applied cover). As described with reference to Figure 13 The seat 41 for the terminals 12a of the heating elements 10 is defined within the cavity 43.

[0108] Conversely, the mold part M4 defines a cavity 42 which is only partially visible, and this cavity 42 is designed to define the remaining part of the outer contour of the base 31, and the housing body 2' of the heater device 1' (within the aforementioned cavity, then there will also be provided with Figure 13the shape of a similar type represented by 40 in

[0109] Therefore, also in this case, as in Figure 14 After positioning the heating element 10 on the mold part M3, the two mold parts M3 and M4 are closed against each other so as to define the volume of a hollow shape into which the polymeric material is injected, which polymeric material will form the body defining both the base 31 and the housing body 2'. Also in this case, after the time required for solidification and cooling, the mold parts M3 and M4 can be reopened and the corresponding semi-finished product of the member 30 can be removed, as Figure 15 represented in

[0110] In Figure 16 schematically represented is a three heating elements 10 having an arched configuration of the type suitable for example for the production of the heater device 1'. In this example, each element 10 includes a respective two electrodes, each electrode being formed by at least one mesh structure 13 and at least one electrical distribution element 14, being shaped for defining the respective terminals 12a projecting downwardly herein. In Figure 16 visible is only a part of the structure 13, namely the part welded to the element 14, the remaining part of the structure being the material 11a with PTC effect of the heating body 11 or being embedded in the material 11a. The electrodes are preferably arranged such that the respective distribution elements 14 are substantially at opposite longitudinal edges of the corresponding heating element 10; this does not constitute a fundamental feature in any case.

[0111] The mesh structure 13 and the corresponding electrical distribution element 14 are schematically illustrated in Figure 17 As can be noticed, the structure 13 has an arched shape and the element 14 consists of a single part which here extends in the longitudinal direction L of the structure 13 so as to be fixed at or near its longitudinal edges. The length of the element 14 is greater than the length of the structure 13 such that the terminal part of the element 14 provides the corresponding terminals 12a. The connection between the two parts 13 and 14 can be of the welding type, for example as previously referred to Figure 7 described. It should be noted that in Figure 17 as in the subsequent figures, the mesh structure 13 is only schematically represented, with very wide mesh openings, for a more direct understanding.

[0112] As previously mentioned, at least part of the mesh structure 13 can be press-fitted into the heating body 11 at the face of the heating body 11 (i.e., by penetrating the structure 13 into the body 11).

[0113] In this regard, a possible technique is in Figure 18is illustrated, where M5 and M6 represent two moving elements of a pressing device, at least one of which is movable relative to the other. Each moving element may define a respective seat 50 (only the seat of the moving element M5 is visible here), and the seat 50 is designed to receive the corresponding parts of the arched electrodes 12 1 or 12 2 and the corresponding parts of the preformed heating body 11. In this case, the body 11 can be obtained via a blanking or punching operation starting from a sheet or web of a polymer having a PTC effect, and then the sheet or web is thermoformed to impart the necessary arched configuration thereto, or the body 11 can be directly injection molded in an arched form.

[0114] Using the corresponding seats 50, the electrodes are disposed between the moving elements M5 and M6, and then the moving elements themselves are pressed against each other such that the mesh structure is strongly pressed or pushed against the opposite main faces of the body 11, thereby causing the structure to penetrate into the faces. For this purpose, in a preferred embodiment, at least one of the moving elements M5 and / or M6 or the corresponding pressing device is configured to heat the body 11 so as to moderately soften it, which facilitates the penetration of the structure into the material 11a. Then, especially after the body 11 has cooled (if heating it is contemplated), the two moving elements M5 and M6 move away from each other, and thus the obtained heating element 10 can be removed from the device, as Figure 19 is illustrated. The heating element 10 can be in the form Figure 20 shown, where the wires of the structure 13 are completely embedded in the material 11a (possibly except for the wires welded to the corresponding distribution elements 14), or if the wires are not completely embedded in the material 11a, the wires can be partially exposed.

[0115] In this type of application, the body 11 is preferably preformed so as to present at least one region (11b, Figure 18 ) having a smaller thickness at the edges for the positioning of the element 14, such that the outer surface of the element 14 will be substantially flush with the surface of the face of the body 11 in which the wires of the structure 13 are embedded.

[0116] The seats 50 of the moving elements M5 and M6 will preferably include portions designed to receive the portions 12a of the element 14 protruding from the structure 13.

[0117] Of course, the device described with reference to Figure 18 and Figure 19 can have a shape different from the illustrated shape, as long as the function of the device remains the same. For example, only one of the two moving elements M5 and M6 may include a seat 50 that is designed to receive the electrodes 12 1 and 12 2Two, with a preformed body 11 disposed therebetween, and wherein the other moving element includes a protruding portion designed to apply mechanical pressure if necessary when the two moving elements are pressed against each other.

[0118] It will be appreciated that the content described with reference to Figures 18 to 20 is also applicable to the case of straight or planar heating elements, such as, for example, as Figure 4 in which case the heating element of course has moving elements M5 and M6 of different shapes and corresponding cavities 50.

[0119] Of course, also in the case of a heating element that is at least partially arched, the polymer material 11a having a PTC effect can be at least partially overmolded on the electrodes 12 1 and 12 2 as described previously with reference to Figures 2 to 3 the heating element. Such a case is schematically represented in Figure 21 wherein M7 and M8 represent two mold parts for injecting the material 11a that will form the heating body 11, and wherein each mold part includes a corresponding cavity that will define the corresponding part of the contour of the arched heating element 10.

[0120] Also in this case, as previously described, it is preferable to provide spacers and / or positioning bodies (here represented by 15'), which, when the electrodes 12 1 and 12 2 are inserted into the mold (for example, into the cavity 51 of the mold part M7 visible in Figure 21 ), will be interposed between the electrodes 12 1 and 12 2 . In the case illustrated in Figure 21 , the body 15', which can be made of an electrically insulating material or a resistive material having a PTC effect, has a substantially comb-like shape arched according to the shape of the electrodes 12 1 and 12 2 , but it is obvious that this shape is to be understood as being provided by way of example only.

[0121] Figure 22 Schematically shows the result of the operation of arranging the electrodes 12 1 and 12 2 one above the other, wherein the spacer body 15' keeps them at an appropriate distance, and the fingers of the body 15' extend in the longitudinal direction of the electrodes themselves, that is, substantially parallel to the electrical distribution element 14. Conversely, Figure 23 illustrates the result of arranging the electrodes 12 1 and 12 2And the step of inserting the integral or "sandwich structure" formed by the spacer body 15' between the components M7 - M8, after the components M7 - M8 are closed, injecting the polymeric material 11a that will form the heating body 11 into the mold. Figure 24 Illustrates the subsequent steps of reopening the mold and removing the heating element after the time necessary for the solidification and cooling of the injected material. Also in this case, the element 10 can be presented with the wires of the structure 13 completely embedded in the material 11a (possibly except for the wires welded to the respective distribution elements 14), or if the molding operation does not envisage complete coverage of the aforementioned wires by the material 11a, the aforementioned wires can be partially exposed.

[0122] Figure 25 is according to Figures 21 to 24 A partial cross-sectional schematic view of the heating element obtained therefrom, from which it can be noted how the spacer body 15' is also embedded in the material 11a in the space between the two electrodes 12 1 and 12 2 in the material 11a.

[0123] Figure 26 and Figure 27 and are schematic illustrations of further possible embodiments of the heating element of the heater device according to the present invention. These illustrate how the element 10 does not necessarily have to be substantially quadrilateral or polygonal, and it can have a partially curved peripheral profile and / or include curved and straight sections.

[0124] Figure 26 and Figure 27 Also show how in various embodiments the electrical distribution element 14 can present a dimensional compensation structure to compensate for possible dimensional variations (e.g., having an intermediate curve), or have a substantially wavy development, or be characterized by a sequence of curves and / or sections oriented or angled in opposite directions.

[0125] This type of shape can prove to be convenient so that the distribution element 14 can elongate and / or shorten in order to compensate for possible dimensional variations due to thermal changes, such as expansion and contraction and / or elongation and shortening in at least one of the directions L and / or W, especially during the heating of the heating body 11 made of the PTC material 11a.

[0126] Preferably, the aforementioned dimensional compensation structure enables compensation for possible dimensional variations, such as the different expansion and contraction between at least a part of the electrodes 12 1 and 12 2 and the different materials of the heating body 11, especially the different expansion and contraction between the electrical distribution element 14 made at least of metal and the body 11 made of the polymer-based PTC material 11a.

[0127] In the illustrated case, both elements 14 represented have a distribution portion 14a extending in the width direction W and a distribution portion 14b extending in the length direction L, each in the vicinity of a respective edge of the corresponding mesh structure 13. Preferably, but not necessarily, the electrical connection portion or terminal 12a is defined at the area of ​​the junction between the two aforementioned distribution portions 14a and 14b. Obviously, an element 14 of this type may have a shape different from that which has been represented by way of example, and include even only one distribution portion.

[0128] Needless to say, also in reference Figures 26 to 27 In an embodiment of the type described, the structure 13 can be fixed to the corresponding element 14 in the manner already described above (e.g. via welding) and likewise the structure 13 can be at least partially embedded in the heating body 11 in the manner already described above (i.e. via mechanical pressure or via overmolding of the material 11a). Figures 26 to 27 In the example, two electrodes of the heating element 10 (preferably electrodes with size compensation structures) are located at corresponding opposite surfaces of the corresponding heating body 11 so as to generate a current circulation in a path substantially perpendicular to the plane of the corresponding surface of the heating body 11.

[0129] In various embodiments, the two electrodes of the heating element 10 are located at the same face of the corresponding heating body 11 so as to generate a current circulation substantially according to a plane parallel to the plane of the corresponding face of the heating body 11. Figure 28 and Figure 29 In the example shown in FIG. 1 , it can be actually noted that two electrodes 12 1 and 12 2 (Preferably but not necessarily, including similar to the previous reference Figures 26 to 27 The size compensation structure of the electrode 12 described in the size compensation structure 1 and 12 2 ) are both located at the same face of the body 11, wherein the corresponding structure 13 is only partially embedded in the material 11a here. Similarly, the two illustrated elements 14 both have a distribution portion 14a extending obliquely in the width direction W and a distribution portion 14b extending in the length direction L near the corresponding edge of the corresponding mesh structure 13, wherein it is possible that part of each portion 14a is directly arranged on top of the material 11a, i.e. without a corresponding part of the interposed structure 13.

[0130] The electrical connection portion or terminal 12a is defined here at the end of the element 14, in particular at the end of the portion 14a. Obviously, the element 14 may have a shape different from that illustrated and comprise even only one transverse or longitudinal distribution portion.

[0131] Also in referenceFigures 28 to 29 In embodiments of the described type, the structure 13 can be fixed to the corresponding element 14 in the manner already described above (e.g., via welding), and the structure 13 can be at least partially embedded in the heating body 11 in the manner described above (i.e., via mechanical pressure or via overmolding of the material 11a).

[0132] In various embodiments, at least one or each electrode of the heating element includes a plurality of mesh structures 13, and the mesh structures 13 are preferably electrically connected to each other by means of at least one electrical distribution element.

[0133] In Figure 30 and Figure 31 an example of this type is schematically shown, in which the electrode denoted by 12 has a first mesh structure 13 and a second mesh structure 13 1 , the first mesh structure 13 is associated with a corresponding electrical distribution element 14 of the type already shown in part A) of Figure 6 , and the second mesh structure 13 1 is connected to the first mesh structure 13 via a further distribution element 14 1 , and the distribution element 14 1 is here substantially L-shaped, or has a part 14a transverse to the second mesh structure 13 1 and a part 14b longitudinal with respect to the second mesh structure 13 1 . The further distribution element 14 1 is preferably fixed (in particular welded) between the two structures 13 and 13 1 at a position intermediate between them.

[0134] As mentioned above, in various embodiments, the heater device according to the invention can be integrated in a component (e.g., a component of a tank) that also performs a function different from the heating of a general medium. For such applications, it is clearly not necessary for the heater device to have a generally arched type or to present one or more arched heating elements; in fact, the heater device can present one or more straight or planar heating elements, for example as in the previously mentioned WO 2017 / 077477 A. Furthermore, one or more planar heaters do not necessarily have to be integrated in the tubular part of such a component.

[0135] For example, in Figure 32 and Figure 33 a component of the type previously denoted by 30 is shown, in the base 31 of which a housing 37 for a straight or planar heating element 10 is defined, and the housing here has a shaped peripheral profile so as to present a curved shape. Also visible in these figures is the lower cover of the base 31 of the type previously mentioned, which is only shown in Figure 32is represented by 32a and serves to enclose the box-shaped part 32. The seat is substantially defined at the lateral wall of the receiving volume of the defining member 30 (i.e., at the bottom wall of the volume represented by T in Figure 11 ).

[0136] Figure 32 and Figure 33 can also be used to illustrate the electrodes 12 1 and 12 2 In the case of, the electrode 12 1 and 12 2 The electrical distribution element 14 of has an extended portion that is closed or substantially closed, or annular or substantially annular. In this example, the distribution element 14 thus has an annular peripheral portion 14d that extends substantially at or near the peripheral edge of the corresponding mesh structure 13. Thus, this peripheral portion 14a extends in both the longitudinal and transverse directions of the corresponding structure 13. In various embodiments of this type, the element 14 may also include one or more intermediate distribution portions, such as portions 14e that converge towards the central region 14f of the element 14. In this example, an opening is defined at the aforementioned central region 14f, and the opening is designed to be coupled to a corresponding positioning element 37a defined within the housing 37 of the base 31 of the member 30. Within the aforementioned housing 37, a seat 37b may also be defined, and the seat 37b has a profile that is substantially complementary to the profile of the distribution element 14 of one of the electrodes (here the electrode 12 2 ) to further assist in the proper positioning of the heating element 10.

[0137] It should be noted that due to the presence of the heating element 10 described, Figures 32 to 33 the member 30 does not necessarily have to also integrate the heater device represented by 1', even though the presence of both the heater 1' and 30 is preferred.

[0138] Also in embodiments of this type, the structure 13 can be fixed to the corresponding element 14 in the manner already described above (e.g., via welding), and the structure 13 can be at least partially embedded in the heating body 11 in the manner described above (i.e., via mechanical pressure or via overmolding of the material 11a). In Figure 32 the case represented by, the structure 13 is completely embedded in the material 11a, but this does not constitute an essential feature.

[0139] Referring again to the illustrated example, the electrical connection portion of the element 14 or the terminal 12a of the heating element 10 extends in a direction perpendicular to the plane of the element itself, and for this purpose, the peripheral portion 14d of the element 14 of the electrode (here the element 14 of the upper electrode 12 1 ) bends inwardly (14d 1 , Figure 33), or in any case shaped so that the terminal 12a of the other electrode can pass through. As already mentioned, in any case, the peripheral portion 14d of the electrode does not necessarily have to be self - enclosed, and it may present at least one break or discontinuity.

[0140] As previously mentioned, the mesh structure 13 is preferably formed by the interlacing or crossing of relatively thin filamentary elements or wires, which preferably have a diameter between 0.2 mm and 0.02 mm. The use of thin wires makes it possible to obtain an efficient fixing of the structure 13 to the material 11a, also due to their at least partial embedding in the aforementioned material, thus counteracting the risk of separation between the components in question.

[0141] For example, wires with a diameter less than 0.1 mm facilitate the embedding of the wires themselves into the material 11a by force (preferably by heating the material 11a, as previously explained), and this also applies to the case of small mesh openings (e.g., even mesh openings less than 0.05 mm). When the material 11a is overmolded on the structure 13, wires with a diameter greater than 0.1 mm are instead more convenient to use, and it is necessary to have wider mesh openings to allow the material itself to pass through, e.g., even mesh openings greater than 1 mm (generally, in the conductive fabrics that can be used for the implementation of the present invention, wider mesh openings correspond to wires with a larger diameter).

[0142] Wires with a relatively large diameter can advantageously be replaced by multiple wires with a smaller diameter. For example, the cross - section of a wire with a diameter of 0.14 mm is substantially equivalent to the cross - section of three wires with a diameter of 0.08 mm: thus, neglecting the skin effect, the current passage that can occur in a wire with a diameter of 0.14 mm can occur in three wires with a diameter of 0.08 mm. However, if one considers the sum of the circumferences of the three wires with a diameter of 0.08 mm (approx. 0.77 mm), it will be noted that it is almost equal to twice the circumference of a single wire with a diameter of 0.14 mm (approx. 0.44 mm). Therefore, it will be recognized that the aforementioned greater "total" circumference corresponding to three thinner wires results in a greater (almost twice as large) contact surface between the mesh structure 13 and the material 11a with PTC effect, and thus better electrical contact and broader total mechanical adhesion between the structure and the material.

[0143] The features of the present invention clearly emerge from the foregoing description, as do the advantages of the present invention. The electric heater device according to the present invention is constructed in an overall simple, inexpensive and reliable manner.

[0144] The fact that the electrodes of the heating element of the device at least include a reticular structure that is at least partially embedded in a material with PTC effect offsets the risk of the electrodes separating or peeling off from the material, which, on the contrary, is encountered in the prior art. The fact that the reticular structure is relatively broad and dense (i.e., formed by relatively thin wires) ensures, in any case, a wide surface of adhesion and contact between the electrodes and the material with PTC effect, and the current flowing between the electrodes themselves has an optimal distribution and intensity. The presence of at least one distribution element in the electrodes prevents the undesired concentration of current on only a few wires of the reticular structure and thus prevents the risk of the wires themselves melting. Moreover, considering that wires with a small cross-section are preferably used to achieve better electrical contact and better mechanical adhesion with the PTC material, this risk can potentially be greater.

[0145] It is clear that those skilled in the art can make many variations to the electric heater device described by way of example without thereby departing from the scope of the present invention as defined in the appended claims.

[0146] In the previously illustrated embodiment, the reticular structure 13 of at least one of the electrodes 12 1 and 12 2 is at least partially directly embedded or encapsulated in the material 11a with PTC effect. In other possible embodiments, the structure 13 is instead at least partially embedded or encapsulated in another electrically and thermally conductive material that at least partially coats the body 11 in electrical contact therewith, such as a conductive adhesive or a conductive coating; in these embodiments, the heating body 11 includes the aforementioned additional material, and thus this material can be used to achieve the mechanical fixation of at least one of the electrodes 12 1 and 12 2 to the heating body itself.

[0147] As previously seen, the production method of the electric heater device according to the present invention envisages fixing the electric distribution element 14 to the reticular structure 13 of the electrodes. Preferably, this fixing is carried out (e.g., via welding) before the reticular structure 13 is associated with the heating body 11 (e.g., by forcing the reticular structure 13 to penetrate into the heating body 11 or via overmolding). However, alternatively, it is also possible to initially associate the reticular structure 13 with the heating body 11 in one of the aforementioned ways and then fix the element 14 to the structure 13. For example, the reticular structure can be associated with the body 11 in such a way as to allow at least part of the reticular structure to protrude from the body 11, and then the distribution element 14 is fixed to the aforementioned protruding part of the structure 13.

Claims

1. An electric heater device (1; 1'), comprising at least one heating element (10), said at least one heating element (10) including a first electrode (12 1 ), a second electrode (12 2 ), and a heating body (11), said heating body (11) including a material (11a) having a PTC effect that is in electrical contact with said first electrode (12 1 ) and said second electrode (12 2 ). Among them, the material (11a) having a PTC effect at least includes a polymer or a polymer-based material, and the device is characterized in that: - The first electrode (12 1 ) and at least one of the second electrodes (12 2 ) includes a mesh structure (13; 13, 13 1 ), the mesh structure (13; 13, 13 1 ) extends in the length direction (L) and the width direction (W), and is in electrical contact with the heating body (11) and at least partially embedded in or enclosed by the heating body (11), and - The first electrode (12 1 ) and the second electrode (12 2 ) of the at least one further comprises at least one electrical distribution element (14; 14, 14 1 ), the at least one electrical distribution element (14; 14, 14 1 ) comprises a formed strip or foil of conductive material, the at least one electrical distribution element (14; 14, 14 1 ) is fixed to the mesh structure (13; 13 1 ) and has at least one distribution portion (14a, 14b) extending in at least one of the length direction (L) and the width direction (W) of the mesh structure (13; 13 1 ), Among them, the heating body (11) is a body that is at least partially molded on the first electrode (12 1 ) and the second electrode (12 2 ). And wherein, between said first electrode (12 1 ) and said second electrode (12 2 ), a spacer body (15; 15') is arranged, and the spacer body (15; 15') is at least partially embedded or encapsulated in the PTC effect material (11a) of a heating body (11) molded on said first electrode (12 1 ) and said second electrode (12 2 ).

2. The electric heater device according to claim 1, characterized in that, The mesh structure (13; 13, 13 1 ) is formed by the interlacing or crossing of substantially linear elements (16a, 16b) of a conductive material having a diameter or cross-sectional dimension between 0.2 mm and 0.02 mm.

3. The electric heater device according to claim 1, characterized in that, The mesh structure (13; 13, 13 1 ) extends substantially parallel to the main surface of the heating body (11).

4. The electric heater device according to claim 1, characterized in that, The mesh structure (13; 13, 13 1 ) is press-fitted into the heating body (11) at the surface of the heating body (11).

5. The electric heater device according to claim 1, characterized in that, The first electrode (12 1 ) and the second electrode (12 2 ) each include one of the mesh structures (13; 13, 13 1 ) and one of the electrical distribution elements (14; 14, 14 1 ).

6. The electric heater device according to claim 5, characterized in that, The first electrode (12 1 ) and the second electrode (12 2 ) are identical to each other.

7. The electric heater device according to any one of claims 1 to 6, characterized in that, The at least one electrical distribution element (14; 14, 14 1 ) has at least one first distribution portion (14a) and at least one second distribution portion (14b), the at least one first distribution portion (14a) extending in the width direction (W) of the mesh structure (13; 13, 13 1 ), and the at least one second distribution portion (14b) extending in the length direction (L) of the mesh structure (13; 13, 13 1 ).

8. The electric heater device according to any one of claims 1 to 6, characterized in that, The electrical distribution element (14) has at least one electrical connection portion (12a) that protrudes beyond the peripheral edge of the mesh structure (13; 13, 13 1 ) or the heating body (11).

9. The electric heater device according to any one of claims 1 to 6, characterized in that, The at least one electrical distribution element (14) has at least one distribution portion (14a, 14b), and the at least one distribution portion (14a, 14b) extends substantially at or near at least one edge of the mesh structure (13; 13 1 ).

10. The electric heater device according to any one of claims 1 to 6, characterized in that, at least one component (11, 12, 13, 14) of the heating element (10) is substantially straight or planar, or substantially arched.

11. The electric heater device according to any one of claims 1 to 6, characterized in that, The at least one electrical distribution element (14; 14, 14 1 ) is welded to the mesh structure (13; 13, 13 1 ).

12. The electric heater device according to any one of claims 1 to 6, characterized in that, further includes a housing body (2; 2') that at least partially covers the at least one heating element (10).

13. An electric heater device (1; 1'), comprising at least one heating element (10), said at least one heating element (10) including a first electrode (12 1 ), a second electrode (12 2 ), and a heating body (11), said heating body (11) being at least partially made of a material (11a) having a PTC effect that is in contact with said first electrode (12 1 ) and said second electrode (12 2 ). Among them, The material (11a) having a PTC effect comprises at least a polymer or a polymer-based material, and wherein at least one of the first electrode (12 1 ) and the second electrode (12 2 ) comprises: - at least one mesh structure (13; 13, 13 1 ), the at least one mesh structure (13; 13, 13 1 ) being at least partially embedded or enclosed in the heating body (11) or in a further electrically and thermally conductive material, the further electrically and thermally conductive material at least partially coating the heating body (11) in electrical contact therewith; and - at least one electrical distribution element (14; 14, 14 1 ) in the form of a shaped belt or foil, said at least one electrical distribution element (14; 14, 14 1 ) extending in at least one of the length direction (L) and the width direction (W) of a corresponding first electrode (12 1 ) or second electrode (12 2 ). Among them, the heating body (11) is a body that is at least partially molded on the first electrode (12 1 ) and the second electrode (12 2 ). And wherein, between the first electrode (12 1 ) and the second electrode (12 2 ), a spacer body (15; 15') is arranged, and the spacer body (15; 15') is at least partially embedded or encapsulated in the PTC effect material (11a) of a heating body (11) molded on the first electrode (12 1 ) and the second electrode (12 2 ).

14. A motor vehicle component (30) comprising at least one electric heater device (1') according to any one of claims 1 to 13.

15. A method for providing an electric heater device (1) according to any one of claims 1 to 13, which comprises the following steps: a) providing the at least one of the first electrode (12 1 ) and the second electrode (12 2 ); b) providing the spacer body (15; 15'); c) firmly associate the spacer body (15; 15') with at least one of the first electrode (12 1 ) and the second electrode (12 2 ) to the heating body (11), Among them, step a) includes: - Provide the mesh structure (13; 13, 13 1 ); - providing the at least one electrical distribution element (14; 14, 14 1 ); and - Fix the at least one electrical distribution element (14; 14, 14 1 ) to the mesh structure (13; 13, 13 1 ). Among them, step c) includes: - The material (11a) having a PTC effect is coated and molded on at least part of the mesh structure (13; 13, 13 1 ) and at least part of the spacer body (15; 15').

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