Cladding element with heating layer in sandwich construction

Abstract

A sandwich-construction cladding element (14) for an interior (16) of an aircraft, comprising at least one core layer (40) and a first outer layer (34), wherein the first outer layer (34) forms a visible side (36) of the cladding element (14), wherein an electrical heating layer (20) is arranged between the core layer (40) closest to the outer layer (34) and the first outer layer (34), the heating layer extending at least over a partial area of ​​the first outer layer (34), and serving to generate heat for radiation through the first outer layer (34), characterized in that the heating layer (20) is a heating paper or heating textile, and the heating layer (20) is perforated and electrically contacted at two opposite edge regions (23), wherein, to achieve a homogeneous surface temperature: - the heating layer (20) has at least two sections (30, 32) with adapted heating resistances between the edge regions (23),which are electrically connected in series,- wherein the sections (30, 32) differ in at least one parameter, wherein the parameter is a perforation parameter of the heating layer (20), on the basis of which individual resistances and thus heating powers for the sections (30, 32) can be adjusted,- wherein the series connection is effected by an electrically conductive transverse strip which extends over the entire width of the heating layer.

Description

The invention relates to a cladding element of sandwich construction for an interior of an aircraft, which cladding element contains a core layer and a first covering layer, wherein the first covering layer, in the intended assembled state of the cladding element in the interior, forms a visible side of the cladding element facing the latter.In an interior, in particular a passenger cabin, of an aircraft, in particular a passenger aircraft, a pleasant room climate is desired with regard to the temperature. It is customary here, for the purpose of heat insulation with respect to the cold outer skin of the aircraft, to introduce insulation material between the latter and the inner wall or the visible side thereof (cladding elements, panels, lining).Boundary conditions (insufficient installation space for sufficient insulation via glass wool packages, heat bridges, draft effects, etc.) can impair this situation. For example, changes in aircraft structure and the resulting thermal bridges across a trim element can result in unacceptably low surface temperatures in flight. Due to the small installation space, sufficient insulation material can no longer be introduced, for example.Furthermore, heatable floor panels in aircraft are known in order to heat a floor of the passenger cabin, in particular in an exit area. Such a floor plate for an aircraft is disclosed in the publication WO 2014 / 001 304 A1. The floor panel includes a first heated plate configured to heat the floor panel; a panel connector disposed in a wall of the regulator housing; at least one power line coupled between the panel connector and the first heated plate and supplying electrical power to the first heated plate, a switch, and a microcontroller connected to the switch and configured to actuate the switch to interrupt electrical power to the first heated plate in the event of an electrical fault in the floor panel.The documents US 2006 / 0201 933 A1, US 2007 / 0 164 015 A1 and EP 1 809 073 A1 disclose a foil heating element, consisting of a structured foil sheet having a first discrete zone formed with a first plurality of holes, which form a plurality of conductive strips and have a first sheet resistance, and a second discrete zone structured with a second plurality of holes, which form a plurality of conductive strips and have a second sheet resistance, wherein at least some of the multiple conductive strips in the first discrete zone are in electrical through connection with at least some of the multiple conductive strips in the second discrete zone and the first discrete zone and the second discrete zone both border a first connecting strip of the foil heating element.US 2017 / 0 238 369 A1 discloses another heatable aircraft floor panel comprising a first cover panel, a second cover panel opposite the first cover panel, and a core having a conductive core portion supporting the first cover panel and the second cover panel, the conductive core portion being electrically insulated from the external environment so that the current applied to the conductive core portion can generate heat that the core gives up to the first cover panel.Furthermore, the publication US 2016 / 0 121 993 A1 discloses a floor panel for an aircraft. The floor panel comprises a panel structure for transmitting forces, wherein the panel structure comprises an upper cover layer, a lower cover layer, a core assembly arranged between the upper and the lower cover layer and a heating layer for heating the floor panel, wherein the heating layer is either provided between the upper and the lower cover layer or is attached to or within the upper and / or lower cover layer, wherein the heating layer is formed as a PTC layer (positive temperature coefficient) with a plurality of electrical conductor tracks which are connected to one another by one or more PTC resistance tracks comprising a PTC material, wherein the electrical resistance of the PTC material increases with increasing temperature.U.S. Pat. No. 3,697,728 A discloses an electrically heatable panel, in particular a floor panel for passenger aircraft. The electrically heatable plate has heating elements, wherein these are arranged in the upper region of the plate, and wherein the heating elements have semiconductor foils. These semiconductor foils, which preferably consist of a glass fibre fabric coated with a silicon elastomer, have flat conductors, preferably copper foil strips, along two opposite edges, which are fastened to the semiconductor foils, for example by clamping.A floor panel assembly consisting of an insulating layer is disclosed in the document US 2018 / 0 176 989 A1. In this case, the floor panel assembly has a heating film, wherein the heating film is fastened to the insulating layer by a first adhesive, as well as a first structural layer which is fastened to the heating film opposite the insulating layer by a second adhesive, a honeycomb layer which is fastened to the first structural layer opposite the heating film by a third adhesive, and a second structural layer which is fastened to the honeycomb opposite the first structural layer by a fourth adhesive.The documents US 2002 / 0 168 184 A1 and DE 199 18 736 A1 disclose a panel component, in particular for a floor panel in an aircraft. The component is substantially constructed from a plurality of layers and has at least one honeycomb core and at least one lower and at least one upper covering layer, wherein the covering layers consist of GRP and / or CFRP layers, wherein a film heater is introduced at least in regions into the plate component and a thermally conductive upper covering plate is provided.US 2009 / 0 236 327 A1, which forms the closest prior art, discloses a resistance heater which is designed as a layered heater. The multilayer heating system has a technical substrate comprising an upper cover layer, a lower cover layer and a core arranged between the upper cover layer and the lower cover layer. The heating system includes a resistive element layer formed near at least one of the upper cover layer and the lower cover layer, a protective layer formed on the resistive element layer, and terminal pads formed over at least a portion of the resistive element layer, the terminal pads being exposed through the protective layer.It is the object of the invention to improve the thermal comfort for passengers and crew in these areas.The object is achieved by a cladding element (also panel or lining) for an interior of an aircraft. The cladding element is constructed in sandwich construction, i.e. by planar contact of different layers with one another. The trim element includes at least a core layer and a first cover layer. The first cover layer forms a visible side of the cladding element in the intended assembled state of the cladding element in the interior space. After the intended installation of the cladding element in an intended aircraft, the visible side therefore faces the interior and can be viewed by passengers, for example. Between the core layer closest to the cover layer and the cover layer, an electric heating layer is arranged. The heating layer extends at least over a partial surface of the first cover layer. The heating layer serves for generating heat and for radiating the heat through the first cover layer, i.e. in the assembled state towards the interior of the aircraft. During operation, i.e. when supplied with electrical energy, the heating layer is thus heated. As a result, heat is then dissipated from the cladding element on its visible side to the interior or the passenger cabin. Since the heating layer (as viewed from the visible side) lies above the core layer--or, in the case of a plurality of core layers: above the uppermost core layer--the heat emission of the heating layer is not impaired by any further core layer. The outer layer thus contains neither a complete (further) nor a part of a (further) core layer.According to the invention, a sandwich structure / structure with embedded planar heating layer (in particular heating element, heating paper, heating textile or the like) is thus obtained for use in regions in the interior (in particular in the aircraft cabin). According to the invention, a technology for the flat heating of sandwich structures results. The invention enables a cost-effective solution with as low a system weight and energy consumption (low power consumption) as possible.According to the invention, the relevant requirements with regard to the mechanical behavior, the fire requirements and the resistance to moisture and media can be fulfilled.According to the invention, an active heating system results which is realized in particular by embedding a heating layer (heating paper) in the fiber composite sandwich structure of the component (cladding element).According to the invention, a heating layer (planar heating element, according to the invention heating paper or heating textile) is thus embedded in a single, double or multiple sandwich construction (intermediate layers, see below, preferably with fiber composite materials). The heating layer (e.g. the heating fabric) is not directly on the visible side, in particular the surface visible to the passenger, but is located under at least one layer, the first cover layer, and optionally intermediate layers, in particular glass fiber-reinforced prepregs. As a result, the heating element is protected from mechanical influences. The visible-side cover layer (first cover layer) is in particular ground, spatulated and painted. The embedded elements (heating layer, conductors, connections, see below) are not visible to the passenger, and there is also sufficient electrical insulation against breakdown.In a preferred embodiment, the cladding element contains at least one intermediate layer and / or a second cover layer opposite the first cover layer. The second cover layer is thus located on the opposite side to the visible side, and therefore faces the outer wall of the aircraft in the assembled state. The cladding element is in particular further stabilized by corresponding further layers. In particular, the planar heating layer or the heating element can thus be embedded in a multilayer (overall) heating layer (covering layer and intermediate layers) in order to protect it from mechanical damage due to impact. The heating layer or the heating paper is embedded in particular on the visible side in the fiber composite structure of the component. Thus, the heat source (heating layer) is embedded near the surface to be heated (first cover layer, visible side), on the one hand, and is protected from mechanical damage by, in particular, three layers of glass fiber-reinforced prepreg (first cover layer and two intermediate layers). This relates in particular to impact events in which it is necessary to prevent the energized heating layer (heating paper) from being able to pose a risk for the passengers or the boarding crew. Owing to the embedding in the passenger-side (overall) passenger compartment (in particular structure: first cover layer and two intermediate layers / heating layer / intermediate layer / core layer), the system is very energy-efficient, since the heat is provided near the surface. At the same time, the heated surface is thermally insulated from the cold outer structure (aircraft casing) on the rear side by the core layer, preferably a sandwich honeycomb structure.In a preferred embodiment, the core layer includes a honeycomb core or the core layer is a honeycomb core. The honeycomb core is in particular a Nomex honeycomb core, in particular with a thickness of 3 mm to 25.4 mm. Alternatively, the core layer may also be made of foam. Particularly stable cladding elements can thereby be created.In a preferred embodiment, at least one of the outer layers (first and / or-if present-second outer layer) and / or-if present-of the intermediate layers is a single- or multi-layer (overall) layer made of fiber composite material. In particular, the layers or plies are formed from prepreg material (pre-impregnated fibers). Cladding elements based on corresponding materials have become established in practice.In a preferred variant of this embodiment, the fiber composite material is therefore a prepreg.According to the invention, the heating layer is perforated. The heating layer thus has through-openings or perforations in the transverse direction to the area of extent in order to create free passages between the layers adjacent to the heating layer. Therefore, particularly in the case of prepregs in the finished state, the binder of the prepregs (particularly resin) penetrates the through holes and forms a bonding column between the adjacent layers. This results in a stable prepreg double plane with pillar-like connections. The remaining (hollow) spaces between the layers are then filled with the material of the heating layer.In a preferred embodiment, the heating layer contains a heating element extending in a planar manner or the heating layer is such an element. The heating element is in particular a heating textile, in particular heating paper. Such heating elements are commercially available as required. A heating element used is, in particular, a heating paper based on carbon fibers embedded in a PEEK matrix. The carbon fibers are oriented more closely in the paper and have a multiplicity of short circuits. As a result, cut-outs (perforations or larger cut-outs etc.) can also be made in the heating paper without completely interrupting the current flow. This also makes it possible to perforate the heating paper in order to achieve a or the abovementioned better embedding in fiber composite structures. The sheet resistance and thus the heating power can be varied in particular by changing the proportion of embedded carbon fibersIn a preferred embodiment, the cladding element contains at least one temperature sensor and / or at least one thermal fuse. Temperature sensor and fuse are each thermally coupled to the heating layer. The securing is in particular a reversible or an irreversible securing. This makes it possible to control the surface temperature (first covering layer) via an embedded sensor in combination with a control system and to protect it from overheating. In particular, the surface temperature of the cladding element in the flight state can thus be controlled to a setpoint value of 19° C. with an accuracy of + / - 2° C.Thus, at least one temperature sensor is embedded, in particular in the immediate vicinity of the heating layer (of the heating paper), by means of which the heating layer (the heating paper) is in particular controlled. The sensor is preferably designed as a PT100 sensor. In order to prevent overheating of the panel, a reversible and / or irreversible thermal fuse can therefore additionally be introduced.In a preferred embodiment, the temperature sensor-if present-is separated from the heating layer by an intermediate layer, in particular a layer of fiber composite material. The intermediate layer is in particular a prepreg layer. This ensures reliable separation between the heating layer and the temperature sensor with good heat coupling.In a preferred embodiment, the cladding element contains at least one electrical connection element for electrically connecting the heating layer and / or, if present, the conductor and / or, if present, the temperature sensor and / or, if present, the thermal fuse. The connecting element is in particular an electrical conductor or a contact element. The contact element is in particular a plug, a socket, terminal, solder joint, etc. The contacting of the heating layer (of the heating paper) is thus effected in particular via suitable conductors. The conductors are in particular likewise embedded in the sandwich composite and in particular connected via a plug / socket etc.The contacting of the heating layer (of the heating paper) takes place in particular via copper strips which are integrated in the fiber composite structure of the cladding element. The temperature sensor is in particular likewise contacted via embedded copper strips. On the relevant side of the component, the conductors of a cable are soldered, via which the component is supplied. On the sides, the heating paper (heating layer) is thus provided in particular with a copper electrode, via which the heating paper can be connected.In a preferred variant of this embodiment, the cladding element has at least one blind hole-like recess which leads from its rear side in the transverse direction to at least one of the connecting elements and is sealed after the connecting elements are electrically connected. The electrical connection is effected in particular by connection of a cable, and sealing by potting. Via an opening (cutout) on the panel (cladding element), the heating paper (heating layer), optionally the (temperature) sensor, and the thermal fuses are thus contacted via the conductors. The opening is cast after the cable is terminated to prevent ingress of moisture and media.According to the invention, the heating layer is thus electrically contacted at two opposite edge regions. The "edge" is to be understood here with respect to the flat direction of extension. The heating layer is thus flowed through in a planar manner from end to end. The electrical contacting is effected in particular by conductor strips which run along the edge.According to the invention, the heating layer comprises between the edge regions at least two sections (e.g. middle section, side section) electrically connected in series, wherein the sections differ in at least one parameter. Depending on the geometry of the cladding element, the sections can be adapted in such a way as to create the most complete possible surface coverage with at least approximately the same heating power per surface. According to the invention, the series connection is effected by an electrically conductive transverse strip (connecting element) which extends over the entire width of the heating layer. On the transverse strip, homogenization of the current density on both sides can then take place.This embodiment is based on the fact that, in the case of larger changes in the energized cross section of the heating layer, for example in the case of milled-out portions, a locally higher heating power (hot spot) can occur locally on account of the higher local current flow. Therefore, if necessary, in order to achieve a homogeneous surface temperature, a plurality of sections (in particular blanks of heating paper) with matched heating resistances are connected in series.According to the invention, the parameter is a perforation parameter of the heating layer. In addition, the parameter can optionally be a width and / or thickness and / or an electrical property of the heating layer. The electrical property is in particular the total electrical resistance, the electrical sheet resistance of the material (local, infinite, proportion of electrically conductive fibers). The perforation parameter is in particular the number, size, shape, distribution pattern or the area proportion of the perforations. Thus, individual resistances, heating powers, etc. can be set for the sections.In a preferred embodiment, the cladding element is as intended for a location in an aircraft where there is not sufficient installation space for sufficient passive thermal insulation of the interior. The cladding element is in particular a wall cladding, floor cladding (floor panel). The location in the aircraft is in particular a door area, area of emergency exits. "Sufficient" is thermal insulation if a surface temperature greater than a minimum temperature can be ensured during normal operation. The cladding element is in particular one for covering an opening mechanism of an emergency exit door of the aircraft. The term "door" is also to be understood here as meaning a flap, a wall element etc. A mechanism is in particular a joint and / or a hook structure, on which the door is anchored or movably and / or removably mounted.According to the invention, this results in a heated cladding element in the region of the emergency exit of commercial aircraft, a heated cladding element in the region of the door / door frame cladding of commercial aircraft or a heated floor plate for aircraft cabins.The invention is based on the following findings, observations or considerations and still has the following embodiments. The embodiments are also sometimes referred to simply as "the invention". The embodiments can also contain parts or combinations of the above-mentioned embodiments or correspond to these and / or optionally also include embodiments not mentioned up to now.The invention is based on the idea of searching for a solution for heated lining in the area of the aircraft cabin.The invention is based on the concept of embedding planar heating elements in a sandwich structure including the embedded electrical conductors, fuses and sensors. The heating layer (the heating paper) is thus in sandwich form, protected from mechanical influences (in particular from impact events). In this case, different sandwich structures (different cover layers and different core materials, depending on the static requirement) can be taken into account.According to the invention, the thermal comfort for passengers can be realized with minimal installation space and at the same time with comparatively low weight. This is of particular interest in areas where there is little volume available for rear (passive thermal) insulation of trim components, such as in the door area or in the area of emergency exits. The design according to the invention realizes a robust integration solution which resists the severe loads in the region of the aircraft cabin (passenger loads, impact events, waste loads, etc.) without sacrificing functionality or jeopardizing the safety of crew and passengers (e.g. short circuits or exposed energized conductors). Moreover, this integration solution is advantageous with regard to resistance to aggressive media such as hydraulic fluid or cleaning agent, for example, and has good fire behavior.Further features, effects and advantages of the invention will become apparent from the following description of a preferred exemplary embodiment of the invention and from the attached figures. In each case, a schematic schematic diagram shows: FIG. 1 shows a structural part of an aircraft with a cladding element in a perspective view, FIG. 2 shows an electric heating layer with electrodes in a) perspective view and b) in plan view in detail, FIG. 3 shows the cladding element from FIG. 1 in a layer section, FIG. 4 shows the layer structure of the cladding element from FIG. 1 in cross section, FIG. 5 shows a partial construction of the structural part from FIG. 1 before final production in a perspective view, FIG. 6 shows a detail of the electrically connected structural part from FIG. 1 in a perspective view.FIG. 1 shows a structural part 2 of an aircraft, here a folding mechanism for emergency exit, which is not explained in more detail. The structural part 2 essentially contains a metallic frame 4 in the form of an articulated supporting structure, to which holders 6 and connecting straps 8 for emergency exit are mechanically rigidly fastened. Where it is structurally possible, an insulation 10 in the form of insulating foam is attached. However, in the intended assembled state, there is no sufficient installation space available to apply a sufficient amount or sufficiently flat insulation 10. An adequate passive thermal insulation of an interior space 16 is therefore not provided on the structural part 2. The structural part 2 is partially surrounded by a silicone seal 12. On the side facing away from the observer in FIG. 1, the structural part 2 is covered by a cladding element 14.In the assembled state, the cladding element 14 faces the interior 16 of the aircraft. The structural part 2 including the cladding element 14 is perforated by a total of four viewing windows 18 in order to allow, when required, a view from the interior 16 to critical structural parts, not shown, of the emergency exit when required.FIG. 2 shows an electric heating layer 20, here in the form of a heating paper. This is a PEEK matrix with embedded carbon fibers 22, FIG. 2 b shows the circled detail in FIG. 2 a. The heating layer 20 has a perforation in the form of a plurality of perforations 24. On two opposite edge sides or edge regions 23, the heating layer 20 has in each case one electrical connection element 26 in the form of a copper electrode. The perforations 24 or the perforation also continue into the copper electrode. The heating paper has a basis weight of 85 g / qm, a sheet resistance of 10-600 ohm / sqr, and a thickness of 90 micrometers. The respective copper electrode is 20 mm wide and 20 micrometers thick. The perforated surface takes up 18% of the area. The heating layer 20 is one of a plurality of layers of the trim member 14 that is sandwich-formed.FIG. 3 shows a longitudinal section through the cladding element 14 according to FIG. 1 at the level of the heating layer 20 in the viewing direction of the arrow III in FIG. 1. In order to create space for an area 28 in which the viewing windows 18 are arranged, a first section in the form of a central section 30 of the heating layer 20 is designed with a reduced width compared to its second and third sections in the form of side sections 32. Connecting elements 26 a, bin the form of the above-mentioned copper electrodes are each located on the end side of the heating layer 20.During operation of the heating layer 20, current is conducted into the latter via the connecting element 26 aand is conducted out again via the connecting element 26 b(or vice versa).In the case of a homogeneously continuous heating layer with uniform local electrical sheet resistance, a local increased heating of the central section 30 compared to the side sections 32 would result during operation because of a local increase in the current density in the region of the central section 30. For this reason, the heating layer 20 is designed in three parts, wherein here the total electrical resistances R1=R3are identical because of the symmetry of the side sections 32 and the resistance of the middle section 30 is designed to be R2<R1with a relatively smaller proportion. Thus, a homogeneous temperature distribution results in the flow of current in the entire heating layer 20.The heating layer 20 is therefore composed of the three partial sections 30, 32, which are each connected on one side via connecting elements 26. In this case, respectively adjoining connecting elements 26 are electrically connected to one another. This results in an electrical series connection of the sections 32- 30- 32.FIG. 4 shows a cross section along the symbolically indicated line IV-IV in FIG. 3 through the entire cladding element 14. Together with two intermediate layers 38 a, b, a three-ply construction is thus obtained. Both the cover layer 34 and the intermediate layers 38 a,bare glass fiber prepreg plies.The next layer is the heating layer 20 and a further intermediate layer 38c. A core layer 40, here a Nomex Honeycomb core in the form of a honeycomb or a honeycomb core, then follows. A further intermediate layer 38d and a second cover layer 42, also a glass fibre prepreg, close off the structure.The layer structure can thus be summarized as follows: three layers of glass fiber prepreg with a thickness of 0.25 mm each are provided on the visible side. Below these three plies is the heating paper in the form of the heating layer 20 and again one ply of the glass fiber prepreg. Below this is the core layer 40 and finally on the rear side there are two layers of glass fibre prepregs. The prepreg is of the PHG600-68-37 type. In the sense of the invention, the three-layer layer of first cover layer 34 and the two intermediate layers 38 could also be understood as a three-layer (single cover) layer of fiber composite material. The same applies to the intermediate layer 38 dand the second cover layer 42 as a two-layer (single-cover) layer.FIG. 4 also shows an electrical conductor 44 for connecting the connecting element 26 a, which runs in the interior of the cladding element 14 in a manner spaced apart from the latter by the corresponding intermediate layer 38 cand electrically insulated from the latter. The conductor 44 is also referred to as a "return copper strip".FIG. 4 shows in an alternative embodiment in dashed lines how a blind hole-like recess 58 is made in the cladding element 14 for the electrical contacting of components, here of the conductor 44, from a rear side 56 of the cladding element 14, in the transverse direction of the cladding element 14, in order to reach the corresponding component. After the contacting, which is also indicated here by dashed lines, the recess 58 is then cast or sealed tightly against environmental influences.FIG. 5 shows a plan view of the intermediate layer 38 cwith a heating layer 20 lying underneath it, which is not visible here indicated by a dashed line. For the electrical contacting of the heating layer 20, a cutout 46 (see also FIG. 4 ) is introduced into the intermediate layer 38 c, of which the cutout is visible above the connecting element 26 b, which is not yet contacted in the figure. The connecting element 26a, on the other hand, is already in contact and is subsequently glued over with an insulating film 48.On the intermediate layer 38c, a temperature sensor 50 with corresponding connection conductors 44 is also arranged and likewise glued or fixed by insulating film 48. As a result, the current temperature of the cladding element 14 or of the heating layer 20 can always be detected. In an alternative embodiment, a thermal fuse 54 (an exemplary installation location is indicated in the figure) which is not illustrated here can also be installed in the structural part 2 (component). Such a temperature sensor is introduced in addition to the temperature sensor 50 in order to ensure additional safety.FIG. 6 finally shows the electrically contacted structural part 2, in which (not visible in the figure) both the temperature sensor 50 and the connecting elements 26 a, bor the conductors 44 leading to these elements are contacted with the aid of the connecting cable 52 shown.List of reference characters2 Structural part 4 Frame 6 Holder 8 Connecting tab 10 Insulating foam 12 Silicone seal 14 Cladding element 16 Interior 18 Viewing window 20 Heating layer 22 Carbon fiber 23 Edge region 24 Aperture 26, 26 a,b Connecting element 28 Region 30 Central section 32 Side section 34 First covering layer 36 Visible side 38, 38 a- d Zwischenschicht layer 40 Core layer 42 Second covering layer 44 Conductor 46 Cutout 48 Insulating film 50 Temperature sensor 52 Connecting cable 54 Thermal fuse 56 Rear side 58 Cutout R 1- 3 Total resistance

Claims

Cladding element (14) of sandwich construction for an interior (16) of an aircraft, which contains at least one core layer (40) and a first cover layer (34), wherein the first cover layer (34) forms a visible side (36) of the cladding element (14), wherein an electrical heating layer (20) is arranged between that core layer (40) which is closest to the cover layer (34) and the first cover layer (34), which heating layer extends at least over a partial surface of the first cover layer (34) and which heating layer is used for generating heat for radiation through the first cover layer (34), characterized in that the heating layer (20) is a heating paper or heating textile, and the heating layer (20) is perforated and electrically contacted at two opposite edge regions (23), wherein: - the heating layer (20) between the edge regions (23) is at least two sections (30, 30, 32) with matched heating resistors which are electrically connected in series, - wherein the sections (30, 32) differ in at least one parameter, wherein the parameter is a perforation parameter of the heating layer (20), on the basis of which individual resistors and thus heating powers for the sections (30, 32) can be adjusted, - wherein the series connection is effected by an electrically conductive transverse strip which extends over the entire width of the heating layer.Cladding element (14) according to Claim 1, characterized in that the cladding element (14) contains at least one intermediate layer (38) and / or a second covering layer (42) lying opposite the first covering layer (34).Cladding element (14) according to one of the preceding claims, characterized in that the core layer (40) contains a honeycomb core or such a core layer or the core layer (40) is produced from foam.Cladding element (14) according to one of the preceding claims, characterized in that at least one of the covering layers (34, 42) and / or of the intermediate layers (38) is a single- or multi-layer layer of fibre composite material.Cladding element (14) according to claim 4, characterised in that the fibre composite material is a prepreg.Cladding element (14) according to one of the preceding claims, characterized in that the heating layer (20) contains or is a heating element which extends in a planar manner.Cladding element (14) according to one of the preceding claims, characterized in that the cladding element (14) contains at least one temperature sensor (50) and / or at least one thermal fuse (54), which are thermally coupled to the heating layer (20).Cladding element (14) according to claim 7, characterised in that the temperature sensor (50) is separated from the heating layer (20) by an intermediate layer (38c).Cladding element (14) according to one of the preceding claims, characterized in that the cladding element (14) contains at least one electrical connection element (26) for electrically connecting the heating layer (20) and / or the conductors (44) and / or the temperature sensor (50) and / or the thermal fuse (54).Cladding element (14) according to Claim 9, characterized in that the cladding element (14) has at least one blind-hole-like cutout (58) which leads from its rear side (56) in the transverse direction to at least one of the connecting elements (26) and is sealed after electrical connection of the connecting elements (26).Cladding element (14) according to one of the preceding claims, characterized in that the parameter is a width and / or thickness and / or an electrical property of the heating layer (20).Cladding element (14) according to one of the preceding claims, characterized in that the cladding element (14) is as intended for a location in an aircraft at which there is not sufficient installation space for sufficient passive thermal insulation (10) of the interior (16).

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