EP1961264B1 - Flat heating element - Google Patents

Description

The present invention relates to a planar heating element according to the preamble of claim 1, in particular for heating user-contacted surfaces in the passenger compartment of a vehicle.

State of the art

DE 41 01 290 It is known that a plurality of heaters can be contacted with a plurality of contact conductors to provide redundancy in the event of failure of individual conductors. However, there are applications in which particularly high demands are made on the safety and robustness of such heating elements.

Commercially Available Products : It is known to silver conductors of copper to protect against corrosion. However, if the silver is not applied pore-tight, the copper can still be attacked. In addition, silver diffuses into the copper over time. This forms a boundary layer of an Ag-Cu alloy, which is very brittle. Fractures of this boundary layer form initial cracks, which also endanger the conductor.

DE 3832342 C1 , DE 19638372 A1 . DE 10206336 A1 It is known that sheath wires can be used in which electrical conductors are provided with a core of steel or precious metal and with a sheath of copper or platinum. The core can be tuned to criteria such as flexibility, tear and tensile strength and flex life, while optimizing the shell for the desired electrical properties. However, such sheath wires are relatively expensive and only limited corrosion resistance.

JP 2002-217058 It is known that a heat conductor consisting of a multiplicity of carbon fibers can be covered by a heat-shrinkable tube. However, such an arrangement is not very break-resistant.

DE 200104011968 It is known that a heat conductor can be provided with a triple different coating. Here, leakage currents between different layers are to be detected by a monitoring device as a heating element fault. Such a multi-layer coating is technically complex and the monitoring electronics expensive.

US 4845343 relates to a heating device in which conductive polymeric PTC heating conductors are incorporated into a textile, wherein shrinkage of the PTC material during manufacture is to be avoided. An increased reliability is not associated with this.

Out US 2003/0047549 A1 For example, a heating element with PTC heating wires is known, which allows improved radiation of heat to the user. Again, there is no relation to increased reliability.

Out US 2003/0047548 A1 a heating element is known in which to avoid electrical breakdown multiple PTC wires are used to prevent the occurrence of electrical welding arcs by a reduced current load. However, overheating of individual wires is not excluded.

WO 2005/089031 and US 2001/0025846 A1 It is known that a heating element may comprise metallically sheathed plastic conductors. This should be further developed here for additional use cases.

Subject of the invention

An object of the present invention is to produce a heating element which is sufficiently durable, corrosion-resistant and inexpensive to manufacture and, in the event of disturbances, goes out of operation without affecting its environment. This is achieved with the subject matter of claim 1.

Another goal is to produce a seat that is efficiently tempered and safe even in continuous operation. This is achieved with the subject matter of claim 4. Further advantageous embodiments are given in the remaining claims and the description.

characters

In the following, details of the invention are explained.

Fig. 1

eine Draufsicht auf ein flächiges Heizelement

Fig. 2

vergrößerte Ansicht eines Leiters des Heizelementes von Fig. 1

Fig. 3

vergrößerte Ansicht eines Einzelstranges des Leiters von Fig. 2

Fig. 4

perspektivischer Schnitt durch einen Sitz mit dem Heizelement von Fig. 1

Reference is made to:

Fig. 1

a plan view of a flat heating element

Fig. 2

enlarged view of a conductor of the heating element of Fig. 1

Fig. 3

enlarged view of a single strand of the head of Fig. 2

Fig. 4

perspective section through a seat with the heating element of Fig. 1

Description of the invention

Heating element 1: Fig. 1 shows a flat electrical heating element. 1

Flat element carrier 8 : The heating element 1 has at least one planar element carrier 8. It may be expedient that at least one of the element carriers 8 is at least partially formed from a textile, knitted fabric, knitted fabric, woven fabric, fleece, a flexible thermoplastic, an air-permeable material and / or a film. In the exemplary embodiment, an element carrier 8 is provided with a fleece of synthetic fibers.

Heating zone 100: It is provided that the heating element 1 has at least one heating zone 100. This is assigned to a surface to be heated or forms this itself.

Heating conductor 2: The heating element 1 has in particular at least one heating conductor 2, which is arranged on and / or in the heating zone 100. Preferably, a plurality provided by heating conductors, which are preferably arranged meandering side by side and electrically parallel to each other. In the exemplary embodiment, a heating conductor is arranged at an average distance of about 2 cm to the next heating conductor and approximately parallel thereto.

High- resistance heating conductor : At least one of the heating conductors 2 has an electrical resistance of between 100 Ω / m and 1000 Ω / m, preferably between 100 and 800 Ω / m, preferably between 300 and 500 Ω / m. In the present case, all heating conductors 2 have a resistance of about 300 Ω / m.

Networked heating conductors : It is provided that at least part of the heating conductors 2 is networked with each other by at least part of the heating conductors 2 being at least partially electrically conductive at contact points 77 between their ends 57. Local Heizleitererstörungen, z. As by local damage when sewing or vandalism, thereby disrupting the operation of the heating element, since in local failure of individual heating element, the heating current is distributed to adjacent heating element. In addition, an inadmissibly high current load due to the crosslinking can immediately damage all the heating conductors 2 and quickly put the heating element out of operation in the event of a fault.

Limited current load : It is envisaged that the regular current load per heat conductor 2 when operating between 10 and 50 V is substantially below 100 mA. This is important to avoid local temperature overshoots on the heating element. Because the temperature at the heating element is usually much higher than the measured by a thermostat in the heating zone 100, averaged in the surface temperature value.

Contacting region 200 : It may be expedient that the heating element 1 has at least one contacting region 200, by means of which the heating zone is contacted. The present heating element has two contacting areas which are spaced apart and arranged approximately parallel to each other on opposite sides of the heating zone 100 therebetween.

Electrode 4 : The heating element 1 has at least one electrode 4 in order to supply current to at least one of the heating conductors 2. Here, two electrodes 4 are provided, one of which extends along the contacting regions 200. They can be meandering and / or straightforward.

Contact conductor 3 : At least one of the electrodes 4 has at least one contact conductor 3. This may comprise, for example, at least one substantially metallic electrical conductor strand 30, preferably made of copper or a copper alloy, which is preferably at least partially provided with a coating of a non-oxidizing or passivated metal, preferably silver or a silver alloy. In the exemplary embodiment, a strand of copper coated with silver is provided. This reduces the price of the heating element, because conventional metallic strands can be used for the contacting conductors.

Connection of contact conductor to electrode : At least one contact conductor 3 and / or one electrode 4 is expediently electrically connected to a multiplicity of heating conductors 2. In the exemplary embodiment, all contact conductors 3 contact all the heating conductors 2.

Similar contact surfaces : It may be expedient that both at least one heating conductor 2 and at least one contact conductor 3 have a similar material at least on parts of their surface. Here both are provided with a coating of silver. This reduces the contact resistance between the two types of conductors. By the same thing, it is understood that the objects concerned have similar or essentially the same values or qualities, at least with regard to their function-relevant properties, in particular their specific electrical conductivity.

Few contact conductors : It may be expedient that at least one electrode 4, as in the exemplary embodiment, has at most two contact conductors 3, preferably at most one contact conductor 3. This allows the material costs are reduced without increasing the contact resistance between heating and contact conductors. For the flexibility of the heating element 2 and the low contact resistance between the heating conductor 2 and contact conductor 3 give a very low resistance at their contact surfaces. As a result, a redundant arrangement of contact conductors 3 is unnecessary.

Non-conductive zones in projection region 108 : The heating element 1 can have at least one projection region 108, in which at least parts of electrical conductors 25 are arranged, which, however, are not current-flown during operation. Such supernatant area 108 are actually superfluous, but production technology sometimes unavoidable. In the present case, a projection region extends along the opposite side of the contacting regions 200 along the heating zone 100. It may therefore be expedient for the heating element 1 to have non-conductive zones 110 in which at least parts of electrical conductors 25 are arranged whose electrical conductivity is at least reduced, preferably eliminated, in other regions, preferably in projection regions 108 or in the region of Trench transitions of a seat. This is done by a targeted pre-damage to the electrical conductors 25 in these zones 110, preferably the heating element 2. This can be z. B. in the area of trench transitions or areas not to be heated prevent the unwanted or random flow of a heating current.

Connecting line 6 : It is provided that the heating element 1 has at least one connecting line 6 in order to feed current from a current source 70 into the heating element 1 via at least one electrode 4.

Temperature sensor 80 : The heating element also expediently has a temperature sensor 80, which interrupts a power supply to the heating element 1 at temperatures between 60 ° C and 80 ° C. These values are averaged over a certain area and therefore always lower than the temperature of the heating element 2. Nevertheless arise on the heating conductors themselves a maximum of 200 ° C to 230 ° C. The temperature sensor 80 may be part of a thermostat as in the embodiment.

Electrical fuse 300 : It is also contemplated that the heating element 1 has at least one electrical fuse 300 which interrupts the operating current in the event of a fault. In the exemplary embodiment, the fuse 300 is formed by heating conductor 2, which burn in the event of exceeding a temperature threshold and no heating current more.

Operating state: In operation, current flows from the current source 70 via a connecting line 6 and the one electrode 4 in the plurality of heating conductors 2. The current flow direction thus extends within the plane of the heating element (not perpendicular thereto). The heating of the heating element 2 heats the heating zone 100. From there, the current then flows via the other electrode 4 and the second connecting line 6 back to the power source.

Electric conductor 25 : FIGS. 2 and 3 show an electrical conductor 25, which can be used for a heating element 1. The electrical conductor 25 may be, for example, a heating conductor 2, a contact conductor 3, an electrical fuse 300 and / or a connecting conductor 6.

Heat-sensitive Conductivity : It may be expedient that the electrical conductivity of at least one electrical conductor 25 is at least temporarily reduced, if its temperature is at least locally between 200 ° C and 400 ° C, preferably between 220 ° C and 280 ° C. Inadmissible high heating of the environment of the heating element can be avoided, even if the thermostat of the heating element fails, z. B. due to age-related welding of the switch contacts, incorrect installation of the heating element or by short-circuiting of the thermostat via heating element. It may be expedient that the electrical conductor 25 at least partially, preferably substantially completely, in said Temperature range is interrupted, preferably irreversible. Then the heating element destroys itself before the environment could be a fire hazard. Unintentional Kurschlüsse the heating element, z. B. by guy wires in the seat are eliminated by local self-destruction of the heating element by itself. Local overheating, z. B. by wrinkling in the heating element due to slipping or incorrect installation in the seat, due to local self-destruction also does not lead to unacceptable temperature increases on the seat. Because surrounding the heating element materials such as foam cushion or fabric covers run only at temperatures above 270 ° C risk of burning devices.

Electrical conductor 25 with Leiterträoer 12 and conductive layer 14 : It is useful if at least one electrical conductor 25 has at least one conductor carrier 12 and an electrically conductive conductive layer 14 disposed thereon. Both could extend into several dimensions. However, they preferably have essentially two or, as here, a main extension direction.

Conductor 25 with conductive particles in matrix : It may alternatively or additionally be expedient if at least one electrical conductor 25 has at least one conductor carrier 12, in particular a matrix, in which electrically conductive particles are embedded. A matrix is a material in a composite material in which other constituents are embedded. By particles is meant here both particles and fibers. Preferably, it is at least partially granules or fibers of carbon, steel or other metals. Fiber-like particles are particularly suitable, since they allow a better current conductivity when embedded in a matrix. Particularly suitable are carbon nanotubes, graphite nano fibers or carbon filaments. This ensures good electrical conductivity, mechanical robustness, corrosion resistance and spinnability of the conductor support material. The conductor carrier 12 is preferably strand-shaped, in particular threadlike, preferably spun.

CNT : Carbon nanotubes (CNT or carbon nanotubes) are tubular Carbon structures. The diameter of the tubes is usually in the range of 1 - 50 nm. Individual tubes currently reach up to millimeter length. Depending on the structure, the electrical conductivity of the tube is metallic, semiconducting or superconducting at low temperatures. CNTs have a density of 1.3-1.4 g / cm ³ and a tensile strength of 45 billion pascals. The current carrying capacity is approximately 1000 times that of copper wires. The thermal conductivity at room temperature is 6000 W / m * K.

Graphite Nano Fibers : Graphite Nano Fibers are (massive) fibers made of carbon which have a diameter about 10 to 100 times thinner than common carbon fibers (about 10 μm in diameter).

Heat-sensitive conductor carrier and conductive layer: Preferably, the conductor carrier 12 is designed so that it loses its material cohesion when a certain temperature value is exceeded. It may be expedient for the conductor carrier 12 to be made of a material that decomposes or vaporizes chemically as soon as certain temperature values are exceeded, so that it is at least partially dissolved or interrupted. As a result, the conductive layer 14 is removed from the supporting base as soon as an inadmissible heating occurs. It may be expedient that the conductor carrier 12 shrinks, contracts and or tears and thereby destroys / ruptures the overlying conductor layer, so that the conductivity of the conductor layer is disturbed. It may be expedient that the conductor carrier 12 is at least partially made of a material with "memory" effect.

Heat-resistant conductor carrier material : It may be expedient that the material of the conductor carrier 12 remains chemically and / or mechanically at least as stable to at least 150 ° C., preferably to at least 200 ° C., preferably to at least 250 ° C., as under standard conditions. As a result, the material is sufficiently heat-resistant for normal heating operation. Temperature-resistant means that the material in question changes its form and its strength negligibly, remains chemically stable, and the same with temperature changes of everyday life Maintains state of aggregation as in standard ambient conditions.

Heat-Melting Conductor Material : It may be desirable for the conductor carrier to melt or soften at temperatures of between 200 ° C and 400 ° C, preferably between 250 ° C and 300 ° C, preferably between 265 ° C and 275 ° C, here at 270 ° C. This ensures a timely interruption of the heating element in case of improper overheating

Robust conductor carrier : It may be expedient that the conductor carrier 12 is at least partially made of a - preferably elastic and tear-resistant - plastic, preferably at least proportionally - preferably completely - from carbon fibers, polypropylene, polyester and / or glass fiber, and / or at least partially from Steel and / or that the material of the conductor carrier 12 has a higher resistance to alternating bending and / or a lower tensile or compressive strength than the material of the conductive layer 14 .. A plastic is any synthetic material that does not occur in nature, in particular polymers and therefrom derived substances such as carbon fibers.

Thermoplastic Leiterträgär material : It may be appropriate that the conductor support of the heat conductor is at least partially, substantially completely, made of a thermoplastic material, preferably a plastic, preferably polyamide, polyester, Kapton or as here polyimide. This allows a cost-effective design. In addition, such threads are soft and neither sharp nor brittle. As a result, the safe operation of neighboring systems (eg seat-occupancy detection) is possible and penetration to the seat surface is much easier to avoid than with carbon fibers.

Thin conductor carrier : It may be expedient that the material of the conductor carrier 12 has a thickness of less than 500 μm, preferably between 100 μm and 2 μm, preferably between 50 and 15 μm.

Thin conductor strands : It may be expedient that the material of the conductor carrier 12 is spinnable or can be pulled out into filaments or wires, preferably into filaments having a thickness of less than 100 μm, preferably less than 10 μm, preferably less than 1 μm. preferably less than 0.1 μm, preferably less than 0.01 μm, and / or. Here are filaments of 10 microns thickness provided. As a result, a high stability and current carrying capacity is achieved with a small thickness of the heating conductor due to a large number of single strands.

Internal conductive layer-conductor carrier connection : The conductive layer 14 is preferably bonded to the conductor carrier 12. This ensures a secure coupling between the conductor carrier and the conductive layer.

Metallizable conductor carrier : For this purpose, it may be expedient that the conductor carrier 12 is metallizable. Such heat conductors are inexpensive to manufacture. Metallization is understood to mean the oversight with a metallic coating, for. B. by electroplating or sputtering.

Thin conductive layer: It may be expedient for the conductive layer 14 to have a thickness of between 1 nm and 15 μm, preferably between 1 nm and 1 μm, preferably between 20 nm and 0.1 μm. This ensures a reliable interruption of the current in the event of a fault, because at an inadmissibly high operating current via an at least partial deformation of the conductor support 12 at least partial destruction of the conductive layer 14 is effected.

Conductive layer of amorphous material : It may be expedient that the conductive layer 14 is applied to the conductor carrier 12 galvanically, as by sputtering or painting technology, as is the case here. This allows the construction of even layers.

Conductor surface inert, refined, inert or with trouble-free corrosion products: It may be appropriate that the conductive layer 14 and / or at least one conductor 25 at least on parts of its surface has a chemically inactive surface under normal environmental conditions, at least on their outward (relative Chemically inactive means inert, ie even with the action of corrosive substances, the so-called object does not change, at least not with such substances as sweat, carbon dioxide or fruit acids. The material may also be chosen to either not corrode or form electrically conductive corrosion products. For this purpose, a metal may be provided, the surface of which is passivatable and / or oxidized and / or chromated. In particular, precious metals such as gold or silver are suitable for this purpose. Here, it is provided that at least one conductor 25 is metal-containing, preferably at least partially made of nickel, silver, copper, gold and / or an alloy containing these elements, at least on parts of its surface, preferably essentially completely of one of the materials mentioned. This reduces the contact resistance at the contact surface between the heating and contact conductors.

Coated conductive layer : It may be expedient that at least part of the surface of the conductive layer 14 is coated, in particular with a plastic and / or a lacquer and / or at least partially with polyurethane, PVC, PTFE, PFA and / or polyester in these embodiments the electrical conductors 25 of the heating element 1 are particularly resistant to corrosion and can also be glued by means of the coating.

Conductor strand 30 : It may be expedient that at least one electrical conductor 25 has at least one conductor strand 30, as here. A conductor strand is a strand in which one, several or many filament-like electrical conductors extend, preferably substantially along the longitudinal direction of the strand. A conductor strand can be constructed as here itself from a plurality of conductor strands.

Strand and filament : A strand is an elongated structure whose length dimensions far exceed the dimensions of its cross section. Preferably, the two dimensions of the cross section have approximately similar dimensions. Preferably, the structure is flexurally elastic, but in a solid state of aggregation. Under filamentous is understood here that the so-called object is formed of a short or long fiber or a monofilament or multifilament yarn.

Many individual strands and bundles of strands : It may be expedient that at least one conductor strand 30 has a plurality of individual strands 33, preferably between 1 and 360, preferably between 10 and 70. In the present case, the heating conductors 2 are designed with approximately 60 individual strands 33. This ensures even with the failure of individual single strands 33 z. B. when sewing, that the heating element 2 remains functional. Here, a plurality of individual strands 33 are combined to form at least one strand bundle 32 in order to increase the stability of the conductor strand 30. Several bundles of bundles 32 are then combined to form an overall bundle 31, preferably between 1 and 20, preferably between 2 and 5. Here, two bundles of bundles are provided. Such a conductor strand 30 has a large surface area and a low resistance, although a large part of the cross section of the conductor strand consists of a non-conductive substance.

Thin single strands: It may be desirable that the single-strand 33 and / or the conductor strand 30 has a thickness of less than 1 mm, preferably less than 0.1 mm, preferably less than 10 microns. Due to the low mass of the heating conductors and the conductor layer and the resulting high speed of their destruction, the environment of the heating element remains completely unaffected.

Support strands: It may be desirable that a conductor strand 30 comprising at least two different types of individual strands 33 and / or conductor bundles 32nd It can be provided that they have mutually different materials and / or different dimensions. Preferably, as here, individual support strands 570 provided that receive a large part of the mechanical load of the conductor strand 30. They are preferably made of a material that is stronger / more resilient / less elastic than the material of the other strands, for example, as here essentially of polyester or steel. Depending on the application, they are preferably thicker and more numerous than the other strands. As a result, even thin strands can be effectively protected against bending and tensile loads.

Material- identical functional elements: It may be appropriate that the conductive layer, the conductor carrier, the support conductors, the contact conductors and / or the heating conductors consist essentially of the same or the same materials, preferably one of said plastics This simplifies the recycling of disused heating elements.

Twisted strands : It may be expedient that the conductor strand 30 and / or at least one single strand 33 preferably have a spiral spatial arrangement, preferably by twisting, twisting or stranding with each other. This allows particularly zugbelastbare heating element.

Cover layer: It may be expedient that a plurality of individual strands 33, bundles of strands 32 and / or conductor strands 30 is at least partially electrically insulated from one another, preferably by at least one single strand 33 being at least partially insulated on its conductive layer 14 by means of an insulating layer. This allows additional protection of the heating element against local overheating.

Glue-coated conductor strands : It can also be provided that at least one conductor strand 30 and / or individual conductor 33 is encased at least in sections with an adhesive, in particular a heat-activatable adhesive. This allows easy mounting of the heating element.

Inner strand 34 and cladding layer 35 : The electrical conductor 25 may, as in here Fig. 3 has at least one filamentary inner strand 34 as a conductor carrier 12 and at least one of these inner strand 12 at least partially enveloping, electrically conductive jacket layer 35 as a conductive layer 14. A cladding layer is a layer which, at least partially, directly or indirectly encases a strand, but not necessarily the outermost layer surrounding the strand.

Conductor weight, shell portion and precious metal content low : It may be appropriate that the electrical conductor 25 weighs between 5 and 50 g / km, in particular between 10 and 15 g / km. It has expediently a metallic proportion between 0.1 g and 10 g, preferably between 1 g and 5 g, preferably between 1 and 3 g per km. In particular, it may be expedient that the electrical conductor 25 has a proportion of between 10% by weight and 50% by weight, preferably between 15% by weight and 25% by weight, of noble metal, preferably silver.

Textile-integrated conductors : It may be expedient for at least one electrical conductor 25 to be arranged, fastened and / or incorporated at least partially at least in sections on and / or in the element carrier 8 of the heating element 1. It may be expedient that at least one electrical conductor 25, preferably as heating conductor 2 or contact conductor 3 is incorporated at least in parts of the element carrier 8, preferably in the weft, part shot or warp thread that he laid on it and by means of an additional sewing or Knitting thread is attached, that it is incorporated as sewing thread therein, and / or that it is glued thereto and / or glued between two layers of the element-carrier 8. Preferably, it is incorporated in the manufacture of the heating element 1 equal to, for. B. as here weft in a knitted fabric This simplifies the manufacturing process. Such a heating element is easy to install, since the conductor strands for feeding electrical energy and / or heating and / or the conductor strands of the additional conductor simply z. B. can be prefabricated as strip material or endless goods and z. B. need only be ironed.

Temperature Robust Resistor: Preferably, at least one heating conductor 25, a conductor strand 30 and / or at least one conductive layer 14 has an electrical resistance which fluctuates within a certain temperature range by a maximum of 50% of its resistance at room temperature (about 20 ° C). Preferably, the fluctuation is even lower, preferably at a maximum of 30%, ideally not more than 10%. The particular temperature range preferably comprises the interval from -10 ° C to + 60 ° C, preferably -20 ° C to +150 ° C, ideally -30 ° C to +200 ° C. This resistance setting can z. By conventional methods such as pre-heating the heating conductors (eg by 10% of their original length), temporarily storing (eg 72 hours) the heating conductors at elevated temperature (eg 50 ° C) by supplying water (eg, water bath at about 30 ° C for 2 hours) or other suitable methods.

Installation options: It may be expedient that the heating element is installed in a vehicle seat, a steering wheel, an armrest, a seat support, a thermal blanket or the like. Fig. 4 shows a heating element, which is installed in a seat 500. The heating element may be in a seat insert or as here between the cover surface and the seat cushion. It may be appropriate that the heating element is installed in a larger subsystem to provide the seat occupant with heating, cooling, ventilation, etc.

Applicability with other patents : It may be desirable for the present heating element to be used as an additional component of known systems or to replace one or more of the components of such systems. For example, the heating element can be used to seat the U.S. Pat. Nos. 6,786,541 ; 6,629,724 ; 6,840,576 . 6,869,140 and the related applications and patents, or the seats of the US Patent Application 2004-0189061 , In addition, the heating element combined with the seats of the U.S. Pat. Nos. 6,893,086 ; 6,869,139 ; 6,857,697 ; 6,676,207 ; 6,619,736 ; 6,604,426 ; 6,439,658 ; 6,164,719 ; 5,921,314 and related applications and patents, or the US Patent Applications 2005-0323950 ; 2005-0331986 ; 2005-0140189 ; 2005-0127723 ; 2005-0093347 ; 2005-0085968 ; 2005-0067862 ; 2005-0067401 ; 2005-0066505 ; 2004-0339035 and related applications. All of the named patents and patent applications are hereby incorporated by reference as part of this document.

Seat with Air Mover: It may be desirable for the seat assembly to include at least one seat or backrest, armrest, upholstery or similar component having a cushion, a temperature change pad and a cover surface. An air mover may be used to provide the seat with conditioned air or ambient air which may be used to convectively or conductively heat or cool the seat or occupant.

Seat with Insert : It may also be convenient to blow tempered air through a permeable cover surface from the seat cushion over the user, thereby providing the seat and user with convective heating or cooling. As in the U.S. Pat. Nos. 6,869,139 and 6,857,697 is shown, the pad may include a passageway through the pad to pass tempered air through the insert to the seat surface. A variety of other optional features disclosed in these patents may be incorporated into the seating systems of the present invention, such as tunnels, sub-channels, deflectors, air-impermeable covers or coatings, or the like. For example, a liner with through-holes may be placed over the sub-channels or sub-tunnels to moderate or direct airflow to the occupant. A heating element can be used to provide heat. A certain amount of conductive cooling can also be achieved by using this system.

Cooling with ambient air: The tempered air can also be combined with ambient air, which is sucked over the user and into the seat. Here, ambient air is drawn through the cover surface and into a mixing area under the cover surface where the ambient air is temperature-wise recycled air is combined. The mixed air is then passed away from the seat, either to be drained or to be passed back to the evaporator and / or mixing area. The ambient air provides convective cooling (or heating) while the conditioned air provides conductive cooling or heating. The mixing area can be z. B. be an open space, which is integrated into a deposit. Examples of seats containing mixing areas include the US Patent Application 2005-0067862 and 2005-0066505 ,

Connection to on-board air conditioning : Temperate air can be generated by a connection to the on-board air conditioning system of the vehicle, by means of a self-contained system or by a combination of systems. A self-contained system includes those that are not connected to the onboard air conditioning system of the vehicle and may include thermoelectric devices, absorbent cooling systems or components, heating elements, and combinations thereof.

Back-flowed surface: It may be appropriate to supply tempered air to the insert without blowing the air over the user. For example, by using an air-impermeable cover surface, tempered air may be fed to a depositor having an open space located below the impermeable cover surface, with air being blown or sucked into the insert to conductively heat or cool the insert and to achieve that with the user.

Opposite flow directions side by side : It may be appropriate that at least a portion of the heating conductors and / or contact conductors are at least partially overlapping or at least approximately arranged along each other and that their current flow directions are at least partially directed opposite to each other. As a result, the electromagnetic fields of the conductors can be compensated.

Folded heating element : For this purpose, it is expedient that the heating element is folded at least in sections. In the exemplary embodiment, this takes place along a folded edge 52 approximately centrally between the two electrodes 4 and approximately parallel thereto. As a result, the two electrodes 4 come to lie one above the other in the reverse current flow direction. The resulting by the folding edge 52 two halves of the heating element 2 are arranged one above the other with opposite current direction.

Exemplary character of the exemplary embodiments: The above statements are intended to make the invention understandable. However, they have only exemplary character. Of course, individual features can also omit, modify or supplement. Also, the features of different embodiments can be combined with each other.

Claims (8)

1. A heating element (20), in particular for heating surfaces in contact with the user in a passenger compartment of a vehicle, comprising at least one electric conductor (25), wherein the electric conductivity of at least one of said conductors (25) is irreversibly interrupted if its temperature is at least locally above an allowable maximum temperature, characterized in that the conductor (25) and/or one of its individual strands (33) has an electric resistivity between 100 Ω/m and 1000 Ω/m and in that the electric conductor (25) includes at least one inner strand (34) having a thickness of less than 500 µm and at least one electrically conductive sheathing layer (35) having a thickness of less than 1 µm at least partially surrounding the inner strand (34).
2. The heating element according to claim 1, characterized in that the conductor (25) and/or one of its individual strands (33) has an electric resistivity of preferably between 100 and 800 Ω/m, preferably between 300 and 500 Ω/m.
3. The heating element according to any one of the preceding claims, characterized in that the electric conductor (25) has at least one inner strand (34) of a thickness preferably between 100 µm and 100 nm, preferably between 15 and 0.1 µm.
4. The heating element according to any one of the preceding claims, characterized in that the heating element 1 includes at least one electric fuse (300), preferably formed of at least one heating conductor (2) which interrupts the operating current in the case of a malfunction.
5. The heating element according to any one of the preceding claims, characterized in that the electric conductivity of at least one electric conductor (25) is at least partially reduced if its temperature is at least locally between 200 °C and 400 °C, preferably between 220 °C and 280 °C.
6. The heating element according to any one of the preceding claims, characterized in that at least one electric conductor (25) comprises one conductor substrate (12) and one electrically conductive layer (14) arranged thereon.
7. The heating element according to any one of the preceding claims, characterized in that at least one electric conductor (25) comprises at least one conductor substrate (12) in which electrically conductive particles are embedded.
8. The heating element according to any one of the preceding claims, characterized in that the material of the conductor substrate (12) remains chemically and/or mechanically stable at temperatures of up to 150 °C, preferably up to 200 °C, preferably up to 250 °C, at least to a similar extent as under standard conditions.

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