EP4093151A1 - Flexible heater with connectors - Google Patents

Abstract

Flexible heating element with connectors

Description

The present invention relates to a heating element for a plug connection, a method for producing the heating element and an electrical device containing this heating element.

Electrical heating elements are used in many different ways. There are a variety of applications, both in industrial applications and in the end customer area, ranging from de-icing in the automotive sector to keeping food warm on the move. In general, they must have high temperature stability and be able to withstand frequently changing temperatures. Furthermore, it is often desirable for the heating elements to have an even temperature distribution.

For example, electric cigarettes require heating elements that are very compact and at the same time have a high heat output. In this application, temperatures of more than 300°C must be reached and at the same time the maximum extension of the heating element in its longest direction should preferably not be greater than 50 mm.

For example, heating elements made of thin substrates with at least one resistance heating structure attached thereto are suitable for such applications. They have a comparatively low mass, so they heat up quickly and are easy to manufacture.

Electrical heating elements often require both power and temperature control or regulation. With heating elements in the range of a few millimeters to a few centimeters, it may be desirable to mount these heating elements directly on a circuit board that is responsible for both power supply and temperature control. For this purpose, the heating element can be attached to the circuit board with a contacting device.

A number of challenges arise when constructing such heating elements and using them with a contacting device. The heat generated by the heating element can damage the contactor. It is therefore desirable to achieve the highest possible temperature gradient so that the heat is generated locally at the heating element and the thermal load on the contacting device is kept low. In the prior art, this is solved by using contacting means that are as long as possible, such as wires.

In addition, the heating elements should be able to be connected to the contacting device as mechanically robustly as possible.

Heating elements made from flat substrates are known from the prior art. Such heating elements can be used in e-cigarettes, for example, to heat up solids or liquids.

Out of DE69517485T2 tubular heating elements made of structured sheet metal are known. These heating elements are electrically contacted via their ring-shaped end pieces.

Out of KR1020180113841A Foil heaters are known which can be rolled up into a sleeve. The heaters are contacted by attaching wires or cables to the rolled-up sleeve.

The designs mentioned from the prior art have certain disadvantages. On the one hand, in the case of tubular heating elements, the contacted annular end pieces can become very hot during operation, so that the contacts are exposed to high thermal stress. Furthermore, a tubular heater in which an annular end piece is contacted is poor in absorbing vibration or thermal stress, so that the contacting device for such a heater is subjected to a considerable load.

On the other hand, contacting a tubular or sleeve-like heating element with wires has the advantage that mechanical stresses can be absorbed better and a longer distance between the heating element and the contacting unit means that the thermal load on the contacting device is reduced. wires, as in KR1020180113841A described, however, have the disadvantage that they have to be attached separately to the heating elements, for example by means of welding, which results in additional process steps. In addition, the contact points between the heating element and the wires themselves are potential failure points that can fail with frequent temperature changes.

The object of the invention is to provide a heating element which overcomes at least one of the problems of the prior art.

The object of the invention was preferably to be seen as providing a heating element which keeps the heating area away from a contacting device as effectively as possible in order to avoid thermal stress on the contacting device. Simultaneously should the heating element be able to be connected to a contacting device in such a way that mechanical stresses are reduced or do not occur at all. In addition, the heating element should be easy to manufacture. Furthermore, the contacting of the heating element should preferably be as robust as possible with respect to frequently changing thermal loads.

The object is solved by the invention according to the category-forming claims. Preferred configurations can be found in one or more dependent claims.

• ein Substrat mit einer ersten Oberfläche und einer der ersten Oberfläche gegenüberliegenden zweiten Oberfläche aufweisend mindestens einen Heizbereich und mindestens einen Anschlussbereich,
• wobei im Heizbereich eine Widerstandsheizstruktur auf der ersten Oberfläche des Substrats angeordnet ist,
• wobei der mindestens eine Anschlussbereich als Lasche ausgebildet ist, die aus dem Heizbereich herausragt und
• wobei die Widerstandsheizstruktur mindesten zwei Anschlussleitungen aufweist und diese Anschlussleitungen sich in den mindestens einen Anschlussbereich erstrecken oder die Anschlussleitungen getrennt von dem mindestens einen Anschlussbereich aus dem Heizbereich herausragen.

In a first aspect, the invention relates to a heating element, comprising:

• a substrate with a first surface and a second surface opposite the first surface, having at least one heating area and at least one connection area,
• wherein a resistance heating structure is arranged on the first surface of the substrate in the heating area,
• wherein the at least one connection area is designed as a tab that protrudes from the heating area and
• wherein the resistance heating structure has at least two connection lines and these connection lines extend into the at least one connection area or the connection lines project separately from the at least one connection area out of the heating area.

The heating element is preferably designed to generate a temperature in the range from 30°C to 800°C, in particular in the range from 30°C to 350°C. The heating element according to the invention can be particularly well suited to withstand frequent temperature changes. The heating element according to the invention preferably withstands at least 500, in particular at least 1000 and particularly preferably at least 5000 temperature cycles.

In principle, the dimensions of the heating element are not further restricted. The heating element can preferably have a length of 0.5 cm to 15 cm. The heating element can preferably have a width of 0.5 cm to 15 cm. The heating surface, i.e. the surface that provides the heating, is preferably in the range of 0.25 - 225 cm ² . If the heating element is formed into a hollow body, also called a sleeve, the diameter can preferably be in the range of 1 mm to 3 cm. Larger diameters, which correlate with less deflection, are also possible.

The heating element is preferably designed in such a way that it can form a plug-in connection with a contacting device. The contacting device is preferably arranged on a circuit board. In one possible embodiment of the invention, this connector can be locked in an end position. The locking can be materially bonded, e.g. by sintering, non-positively, e.g. by clamping, or form-fitting, e.g. by hooking.

The heating element according to the invention has a substrate with a first surface and a second surface opposite the first surface.

Preferably, the substrate is in the form of a sheet, such as a foil or sheet. In one possible embodiment, the thickness of the substrate is essentially constant. In particular, the thickness varies by at most +/- 10%. The thickness of the substrate is particularly preferably in the range from 20 μm to 1000 μm.

The substrate thickness is preferably 0.02 mm - 2 mm, in particular 0.05 mm - 0.5 mm.

The width and the length of the substrate are each preferably in the range of 0.5 cm - 15 cm.

The material of the substrate can be selected from the group consisting of polymers, metals, ceramics, glasses or combinations thereof. In a preferred embodiment of the invention, the substrate comprises or consists of a metal. The substrate can particularly preferably have a metal foil or a metal sheet.

The substrate is preferably flexible enough that, starting from a flat state, it can be bent together to form a hollow body, in particular a sleeve. As a result of the bending together, either the first or the second surface can be arranged towards the interior of the hollow body.

The substrate is particularly preferably electrically insulating on its first surface. In the event that the material of the substrate itself is electrically insulating, a separate insulating layer can be dispensed with, for example if it is a polymer. In the event that the substrate comprises an electrically conductive material, for example a metal, an insulating layer is arranged on the first surface.

Electrically insulating layers that electrically isolate the electrically conductive substrate from the heating structure are particularly suitable as insulating layers. In general, layers with a specific resistance of > 10E10 Ω * cm are suitable for this.

The insulation layer preferably comprises a metal oxide layer, in particular an anodized metal oxide layer or a thermally produced metal oxide layer or a metal nitride layer or a metal oxynitride layer. In a particularly preferred embodiment of the invention, the insulation layer is a metal oxide layer, in particular an anodized metal oxide layer, or a metal nitride layer or a metal oxynitride layer. If the insulation layer is one of the metal layers mentioned, the insulation layer preferably has no further layers that do not fall under the preceding layer definitions. Furthermore, it is possible for the insulation layer to be designed as a combination of different metal oxide layers, metal nitride layers or metal oxynitride layers stacked on top of one another.

The advantage of an insulation layer that is or has a metal oxide layer, a metal nitride layer or a metal oxynitride layer is that such insulation layers have both good insulating properties and can also be made as thin as possible. The thickness of the insulating layer is preferably in the range from 0.02 μm to 20 μm. The insulating layer also has at least one other component selected from the group consisting of aluminum oxide (Al ₂ O ₃ ), aluminum titanate (Al ₂ TiO ₅ ) , titanium dioxide (TiO ₂ ), (SiO ₂ ), silicon oxide (SiO), magnesium oxide (MgO), magnesium titanate (MgTiO ₃ ), a binary zirconia alloy, a ternary zirconia alloy, boron nitride (BN), aluminum nitride (AIN) and Silicon nitride (Si ₃ N ₄ ) and combinations thereof.

The substrate is preferably formed from a metal foil or a metal sheet. In particular, the substrate consists of a metal foil or a metal sheet with an insulating layer. The metal foil is preferably formed from such materials that form dense metal oxide layers with high electrical insulation during oxidation, in particular anodic or thermal oxidation. This serves to produce a corresponding insulation layer. Foils made of aluminum, steel, titanium, niobium or tantalum are therefore particularly suitable as metal foils. Alloys containing chromium and aluminum are particularly suitable as materials for steel foils. The steel is preferably an FeCrAl alloy, in particular X8CRAl20-5 or FeCr25Al5. Some metals, such as aluminum or FeCrAI alloys, form particularly stable metal oxide layers, so that the insulation layer can be prevented from flaking off or cracks forming in the insulation layer, even in the event of rapid temperature changes or bending.

Due to the use of metal foils for the production of a substrate, in particular when using an aluminum foil, a distortion of the metal foil during the heating up of the heating element is prevented.

The substrate has a heating area and at least one connection area. The heating area and the at least one connection area of the substrate are preferably formed in one piece. Optionally, the substrate has at least one joining area.

The heating area includes a resistance heating structure configured to heat the heating element. The heating area is preferably a continuous area of the substrate that has no interruptions. The heating area is preferably covered as completely as possible with a resistance heating structure, in particular at least 50% of the area of the heating area, in particular 70% and particularly preferably at least 85%, is provided with a resistance heating structure. Here, the area of the resistance heating structure is determined by determining the area within the perimeter of the heating structure (see, for example, in 2 the hatched area 21 with a dashed perimeter). In a preferred embodiment, the resistance heating structure is distributed as evenly as possible over the heating area. Alternatively, the resistance heating structure can be arranged in the heating area in such a way that one area is specifically heated more than another, for example in the form of a temperature gradient. For example, a temperature gradient with colder temperatures can be set in the direction of at least one connection area in order to reduce the thermal load on the contacting device.

The resistance heating structure may have any shape as long as it can be sufficiently heated by current flow. For example, the resistance heating structure can be designed as a heating meander. Preferably, the resistance heating structure consists of a metal structure. The resistance heating structure preferably has an electrical resistance of from 0.1 Ω to 30.0 Ω, in particular from 0.5 Ω to 10.0 Ω. The electrical resistance is formed between two terminals of the resistance heating structure.

In a particularly preferred embodiment of the invention, the resistance heating structure has a thickness of less than 0.6 mm, particularly preferably less than 300 μm. Furthermore, the resistance heating structure preferably has an average thickness of 0.5 μm or more.

The resistance heating structure, made in particular of a metal structure, can have any shape. For example, it is possible to form a heating structure in a square shape. It is also possible to form a heating structure with an essentially straight line structure.

In particular, the heating structure has a meandering structure. Such a meandering structure can be formed, for example, from a coherent, interwoven and/or nested and/or interlocking line structure. The individual sections, in particular the individual line sections, can be made relatively narrow, for example with a width in the range of 5 μm-50 μm, in particular 10 μm-20 μm. The distances between two conductor tracks are preferably in the range of 50 μm or more, in particular 100 μm or more and very particularly preferably 200 μm or more. Furthermore, the distance between two conductor tracks is preferably in the range of 5 cm or less, in particular 1000 μm or less and very particularly 500 μm or less. The distance between two conductor tracks can preferably be at least 50 μm or 100 μm.

The resistance heating structure, which is present in particular in a meandering form, can cover any large area due to the structure formed.

The resistance heating structure preferably comprises or consists of a metal. For example, the metal can be selected from light metals such as aluminum or precious metals such as gold, silver, platinum, or combinations thereof.

The resistance heating structure can be produced, for example, by means of thin-film processes, thick-film processes or by stamping from sheet metal. The resistance heating structure may be formed from a patterned metal foil. If such an embodiment with regard to the resistance heating structure is present, the resistance heating structure can be produced in a separate process and then applied to the substrate.

The resistance structure made of a structured metal foil can optionally have an electrically insulating layer, e.g. an oxide layer, on its surface which is brought into contact with the substrate. This insulating layer can electrically decouple the resistive layer from metallic substrates, even if the substrate does not have an electrically insulating surface.

In a further embodiment of the invention, the resistance heating structure, which is preferably formed from a structured metal foil, can be placed floating on the substrate. The resistance heating structure so produced may be reversibly or irreversibly attached to the substrate. For example, the resistance heating structure can be attached to the substrate due to its spring effect. Either the resistance heating structure can be pressed against the inner wall in the interior of a hollow body, analogously to a clock spring. Alternatively, the resistance heating structure can be analogous to a clamp on the outside of a hollow body to be stuck. A heating structure in the form of a structured metal foil can preferably be attached to the substrate by gluing, sintering, soldering or welding.

Furthermore, it is possible for the heating structure to be produced from a metal-containing paste and/or a metal-containing ink. Such a metal-containing paste and/or ink can be applied to the insulation layer as part of a printing process, in particular as part of a screen printing process.

In a particularly preferred embodiment of the invention, the heating structure is formed from a paste containing noble metal. In particular, the noble metal can be selected from the group consisting of platinum, silver and gold and combinations thereof.

In a further embodiment of the invention, the heating structure is a metal structure produced by means of thin-film metal deposition (sputtering).

Furthermore, the substrate has at least one connection area, which is designed as a tab and protrudes from the heating area. The connection area can be designed in such a way that the heating element can be mechanically fastened via the connection area, e.g. by clamping. According to the invention, the shape of the tab is not further restricted and can, for example, have a rectangular or approximately rectangular shape.

The length of the tab-shaped connection areas is preferably in the range from 1 mm to 10 cm, in particular in the range from 2 mm to 5 cm and very particularly preferably in the range from 3 mm to 2 cm. For example, a better thermal decoupling of the contacting device from the heating element can be achieved by longer connection areas in the form of tabs, e.g. with a length in the range of 1 cm - 10 cm. In one possible embodiment of the invention, the length of the connection area is at least 1 mm, in particular 2 mm and very particularly preferably at least 10 mm. In addition, the length of the connection area can be in the range of 10 cm or less, in particular 5 cm or less and particularly preferably 1 cm or less.

In one possible embodiment of the invention, the width of a tab-shaped connection area can correspond to at most 70% of the width of the substrate, preferably at most 50% or at most 25% of the width of the substrate and in particular at most 10% of the width of the substrate. Furthermore, the width of a tab is at least as wide as a connection line. In particular, the tab is at least twice as wide and very particularly preferably at least ten times as wide as a connecting line. For example, the tab can have a width of at least 1 mm, at least 5 mm or at least 10 mm. Overall, the width of all tab-shaped connection areas together is preferably at least 10%, at least 20%, at least 50%, at least 70% or at least 90% of the width of the substrate. For values over 90% of the width of the substrate, the areas between two connection areas can be considered as slots.

In principle, the number of connection areas in the form of lugs is not further restricted. In one possible embodiment of the invention, the heating element has two or more connection areas, in particular three or more. In the case of two or more connection areas, the connection areas are preferably arranged on the same edge of the substrate. This means that the connection areas on the same end of a substrate can protrude from the heating area.

In one possible embodiment, at least one connection area of the substrate can be rotated relative to the heating area, in particular by approximately 90°. In other words, a tab of a connection area can be twisted out of the plane of the heating area. This can be particularly advantageous when the heating element is bent into a hollow body and the connection areas are no longer in one plane. By twisting the connection areas, they can be aligned parallel to one another, which can make contacting easier, particularly in a plug-in connection.

In a further preferred embodiment of the invention, the at least one connection area can have a curved profile, in particular an L-shaped, S-shaped or U-shaped profile. As a result, the rigidity of the connection area can be increased compared to a non-bent connection area.

At least one connection area of the substrate is preferably arranged as an extension of an edge of the heating area. Optionally, two connection areas can each be arranged as an extension of two opposite edges of the heating area. As a result, the connection areas can preferably be arranged next to one another when the heating element is formed into a hollow body.

Furthermore, the resistance heating structure has connection lines which protrude from the heating area. The leads may be formed from the same material as the resistance heating structure or from a different material. In contrast to the resistance heating structure, the connection lines can be designed in such a way that they heat up less than the resistance heating structure when current is applied. The connection lines are used for electrical contacting of the resistance heating structure. The connecting lines preferably have contact surfaces, also called contact pads, at the ends pointing away from the heating structure. The contact surfaces each have an area which is suitable for electrically connecting a contacting device to the connection lines, and thus also to the resistance heating element.

The connection lines can preferably be arranged together on at least one connection area or each on a separate connection area. The connection lines can completely or partially overlap with one or more connection areas. For example, a connection line can be arranged on at least one connection area, while a connection line projects out of the heating area offset to at least one connection area. In one possible embodiment, the connection lines can be arranged completely on the at least one connection area; in particular, the connection lines can be connected to the connection areas in a materially bonded manner. In particular, if the connection lines are produced by means of a thin-film or thick-film method, they are arranged on the at least one connection area and connected to it in a materially bonded manner. In a preferred exemplary embodiment, the substrate has two connection areas and a connection line is arranged on each connection area.

Alternatively, the connection lines can protrude from the heating area offset to the at least one connection area. This is possible in particular when the resistance heating structure is made from stamped sheet metal. Connection lines are used for electrical contacting of the resistance heating element. The at least one connection area is used for mechanical contacting or fastening. Both the at least one connection area and the connection lines can be contacted by a contacting device, e.g. on a circuit board.

The connection lines are preferably arranged on the at least one connection area. One connection line is particularly preferably arranged on each connection area of the substrate.

In a preferred embodiment of the invention, the at least one connection area is designed as a spring element. For this purpose, one or more connection areas of the substrate can be formed, for example, in an S-shape or in a serpentine shape. In this way, vibrations or mechanical stresses can be absorbed particularly well. Mechanical stresses can occur, for example, when materials with different expansion coefficients are combined with one another. In particular, a contacting device for connecting the heating element can be relieved by a spring-like design of the connection area. Optionally, the heat conduction path can also be provided by an S- or snake-shaped design of the connection area extended, so that the heating area is better thermally decoupled from a contacting device by the connection area.

The connection lines are particularly preferably arranged on the at least one connection area designed as a spring element. Alternatively, the at least one connection area and at least one connection line can protrude separately from the heating area and each be designed as a spring element.

In a further preferred embodiment of the invention, the at least one connection area is at least partially enclosed in a ceramic element. The ceramic element serves as a heat sink and reduces the heat conduction of the connection area. The ceramic element can be formed from a ceramic slip, for example. The ceramic slip can be arranged as a paste around at least one connection area and then sintered to form a ceramic element.

Alternatively, the ceramic element can also be produced separately from the at least one connection area and then arranged around the connection area, for example in the form of two halves of a ceramic body which are clamped around the at least one connection area.

Oxide ceramics such as aluminum oxide or nitride ceramics, for example, are used as ceramics for the ceramic element.

In another preferred embodiment, the at least one connection area has a fastening means. The fastener can be used to lock the heating element to the contacting device. For example, the heating element can snap into a contacting device. The attachment means can be selected from hooks, claws, springs and collars. Hooks may be attached to the terminal areas or formed from the terminal areas of the substrate itself, e.g., by bending. Optionally, the at least one connection area can be designed in such a way that it forms a bayonet lock with a contacting device. Depending on the configuration, the fastening means can enable reversible or irreversible locking.

Optionally, the heating element can also be welded, soldered or sintered to the at least one connection area with a contacting device.

The heating element can be flat or have a curved shape. In one possible embodiment of the invention, the heating element can have an L, S or U profile. In this way, for example, the rigidity of the heating element can be improved. If the heating element has a curved shape, preferably the opposite ends of the Substrate, in particular the edges out to each other to form a hollow body. The hollow body can also be referred to as a sleeve or tube. The heating element can be bent such that the first surface of the substrate, which has the heating element, is arranged inside the hollow body. Alternatively, the heating element can be bent into a hollow body in such a way that the first surface of the substrate is arranged on the outside of the hollow body. The ends of the substrate that do not have a connection area are preferably bent toward one another.

The hollow body can have, for example, a circular, an elliptical, a triangular or a polygonal cross section. As a result, the stability of the hollow body can be increased.

If the heating element is designed as a hollow body, the opposite edges of the ends of the substrate can preferably touch or form a gap. Alternatively, the mutually bent ends of the substrate can overlap.

In a preferred embodiment of the invention, the substrate has at least one joining area. The at least one joining area preferably has no resistance heating element. In particular, the joining area can be designed in such a way that overlapping ends of the substrate overlap in the joining area, e.g. when the heating element is bent and forms a hollow body. Furthermore, the at least one joining region can have a structure that is suitable for fixing the heating element in a bent state, in particular as a hollow body.

Particularly preferably, the heating element can be bent into a hollow body in such a way that the heating area overlaps with the joining area. The heating area can thus extend along the entire circumference of the hollow body, so that heating can take place as uniformly as possible. Overlapping areas of the substrate are preferably arranged in such a way that no resistance heating structure is arranged between overlapping areas.

In a preferred embodiment of the invention, the ends of the substrate bent towards one another are fixed to one another, in particular in at least one joining area of the substrate. This fixation can be materially or form-fitting. The cohesive fixing can take place, for example, by welding, gluing or sintering the ends of the substrate. This fixation can increase the rigidity of the heating element.

The form-fitting fixation can take place, for example, by the mutually bent ends of the substrate engaging in one another like pieces of a puzzle. For this purpose, the substrate preferably has two joining areas that are structured in such a way that the opposite ends of the Substrates can hook into each other using the key-lock principle. Alternatively, at least one joining area of the substrate can have at least one tab which, after bending together, is guided through at least one opening in the other end of the substrate. In particular, the opening is located in a further joining area. Optionally, the at least one tab that is guided through the opening can also be fixed in a materially bonded manner. This principle is exemplified in Figure 6A .

In one embodiment of the invention, the heating element has a ring or sleeve that surrounds and fixes the bent heating element in the bent position. In one embodiment, the curved heating element is pressed against the ring or sleeve from the inside by the resilience of the substrate. Optionally, the heating element bent into a hollow body can be fixed to the ring or the sleeve.

The ring can function as a flange and is preferably designed in such a way that further elements are attached to the flange

• Bereitstellen eines Substrats,
• Anordnen einer Widerstandsheizstruktur auf dem Substrat und
• Zuschneiden des Substrats unter Erhalt eines Heizbereichs und mindestens eines Anschlussbereichs, der als Laschen ausgebildet ist und aus dem Heizbereich herausragt.

A second aspect of the invention relates to a method for producing a heating element according to the invention, comprising the steps:

• providing a substrate,
• arranging a resistance heating structure on the substrate and
• Cutting the substrate to obtain a heating area and at least one connection area, which is designed as tabs and protrudes from the heating area.

The substrate and resistive heating structure preferably have the features and properties described herein. In particular, a heating element according to the invention can be produced by the method according to the invention.

According to the invention, a resistance heating structure is arranged on the substrate. For example, the resistance heating structure can be manufactured using aerosol deposition method (ADM), thin film or thick film processes. Thin-film methods (physical vapor deposition; PVD) can be selected, for example, from sputtering, evaporation methods (eg ion beam evaporation) and ion plating. Thick film processes include printing processes such as screen printing.

Alternatively, a resistance heating structure can be produced by stamping a conductor track from a starting material such as sheet metal or foil. A stamped resistance heating structure can be materially bonded or force-fitted to the substrate will. For example, the resistive heating structure can be clamped onto the substrate. Alternatively, the resistance heating structure can be attached to the substrate by means of welding, soldering, gluing or sintering.

The substrate is preferably cut in such a way that a joining area is obtained in addition to the heating area. The joining area can be used to join mutually bent opposite ends of the substrate to one another.

In one possible embodiment of the invention, two or more connection areas can be created by trimming the substrate by cutting a slit in the substrate, which partially divides the substrate into two or more parts, which then form connection areas. The width of a slit that can be formed when cutting can be, for example, 100 µm to 1 mm wide. In a preferred embodiment, the slot between at least two connection areas does not extend further than 50% of the length of the substrate into this substrate.

In a preferred embodiment, after the substrate has been cut to size, opposite ends of the heating element can be brought together in order to obtain a hollow body. The ends of the substrate that do not have a connection area can preferably be bent toward one another.

If a hollow body is formed, the ends of the substrate that are guided toward one another can be attached to one another in a materially or positively bonded manner. In one possible embodiment of the invention, material-locking and positive-locking fastening methods can be combined with one another. The cohesive attachment can be done for example by gluing, welding, soldering or sintering. The form-fitting fastening can take place, for example, by interlocking the ends with one another in the manner of a puzzle.

In a third aspect, the invention relates to an electrical device having a circuit board, with a heating element according to the invention being plugged onto the circuit board in order to make electrical contact with the circuit board.

The circuit board preferably has a contacting device. Optionally, the circuit board has additional electronic components. The contacting device is preferably designed to make electrical contact with the heating element and to fix it mechanically. The contacting device can be designed in such a way that the electrical contacting takes place at the same time as mechanical fixing. Alternatively, the contacting device can be designed in such a way that the electrical contacting and the mechanical fixing take place separately from one another. In particular, a separate electrical and mechanical contacting may be necessary if the connection lines and the at least one connection area do not overlap, but are designed separately from one another.

The heating element according to the invention is plugged onto the circuit board and, in particular, the heating element is plugged into the contacting device.

In a simple case, the contacting device can be designed according to the principle of a spring-loaded terminal.

In one possible embodiment, the contacting device and the at least one connection element can form a bayonet lock. Alternatively, the contacting device can be designed as an FPC connector. In the case of an FPC connector, contact can preferably be made by clamping. This has the advantage that the contact can be released again without being destroyed.

In a preferred embodiment of the invention, the contacting between the contacting device and the heating element can be materially bonded, for example by welding, sintering, soldering or gluing. The type of material-to-material contacting depends on the temperature to which the contacting device is exposed and can be selected accordingly by a person skilled in the art.

Particularly preferably, the heating element is contacted on the circuit board without additional wires and cables.

The invention is explained in more detail below using exemplary embodiments with reference to the attached drawings.

• Abbildung1 ein erfindungsgemäßes Heizelement in der Draufsicht (1A) und in perspektivischer Ansicht (1B),
• Abbildung 2 eine Skizze eines erfindungsgemäßen Heizelements mit verschiedenen Anordnungen der Anschlussleitungen,
• Abbildung 3 eine Ausführung des erfindungsgemäßen Heizelements bei dem die Anschlussbereiche als Federelemente ausgestaltet sind,
• Abbildung 4 ein Heizelement aufweisend ein Keramikelement, das um zwei Anschlussbereiche herum angeordnet ist,
• Abbildung 5 eine Ausführung des erfindungsgemäßen Heizelements bei dem die Anschlussbereiche als Befestigungselemente ausgestaltet sind und
• Abbildung 6 zwei Ausführung des erfindungsgemäßen Heizelements aufweisend unterschiedlich strukturierte Fügebereiche
• Abbildung 7 Verfahren zur Herstellung eines Heizelements in Form eines Hohlkörpers

In these show:

• Illustration 1 a heating element according to the invention in plan view (1A) and in perspective view (1B),
• Figure 2 a sketch of a heating element according to the invention with different arrangements of the connection lines,
• Figure 3 an embodiment of the heating element according to the invention in which the connection areas are designed as spring elements,
• Figure 4 a heating element comprising a ceramic element which is arranged around two connection areas,
• Figure 5 an embodiment of the heating element according to the invention in which the connection areas are designed as fastening elements and
• Figure 6 Two versions of the heating element according to the invention having differently structured joining areas
• Figure 7 Process for manufacturing a heating element in the form of a hollow body

In Figure 1A a heating element 1 according to the invention is shown. In this variant, the heating element is flat and forms a heating blade, so to speak. The substrate 10 has a heating area 11 and two connection areas 12, 12'. The substrate 10 has a heating element 20 in the heating area 11 . The heating element is designed here as a meander, for example. The connection areas 12, 12' have connection lines which are designed as contact pads 30. FIG. Figure 1B shows a section of the same heating element in a perspective view. Shown here by way of example is a substrate 10 which has a metal foil 13 with an insulation layer 14 arranged thereon. The heating element 20 and the connection lines 30 are arranged on the insulation layer 14 .

Figure 2 shows two schematic representations of the heating element 1. A heating element 20 is arranged on a substrate 10. FIG. In Figure 2A the connection lines 30 are arranged on the connection areas 12 . In Figure 2B On the other hand, the connection lines 30 are arranged offset to the connection areas 12 and protrude from the heating area. The shaded area 21 in FIG. 2A illustrates the area covered by the heating element 20 on the substrate.

In Figure 3 a heating element 1 according to the invention is shown, in which the connection areas 30 are designed as spring elements 60 . The dashed area 60 indicates the S-shaped part of the connection areas 12, 12'. In the side view rotated by 90°, the spring element is also shown in the dashed area.

Figure 4 shows a heating element 1 according to the invention, in which the connection areas 12 are enclosed in a ceramic element 70 . The ceramic element 70 is preferably made from a ceramic slurry which is sintered around the connection areas.

Figure 5 1 shows a heating element 1 according to the invention with a fastening element 40. The fastening element 40 is formed from the substrate, for example by cutting or punching. The fastening element arranged on the connection area is then bent in such a way that it forms a hook. Figure 5B shows the generated heating element Fastening elements in side view. The fastening element 40 is hooked into an eyelet of a contacting device 100 here, for example.

Figure 6 shows a schematic representation of the heating element 1 according to the invention Figure 6A a heating element 1 is shown, in which the substrate 10 has two joining regions 17 (shown in phantom). The joining areas 17 are free of the heating element 20. The joining areas 17 are structured as tabs and slots. When the heating element 1 is bent into a hollow body, the tabs of one heating area can be guided into the slots of the other heating area in order to fix the hollow body in this state. Bending of the heating element is shown by the curved arrows. In Figure 6B the joining areas 17 are structured like a jigsaw puzzle, so that the structures can interlock and interlock when these joining areas 17 are bent towards one another.

Figure 7 Figure 1 shows an exemplary method in accordance with the present invention. In FIG. 7A, there is shown a rectangular substrate 10 with a resistive heating structure 20 disposed thereon. The resistance heating structure has connection lines 30 which are designed as contact pads towards the end. Subsequently, the substrate is cut in step 100, whereby a heating element 1 is obtained (7B). The heating element 1 has a substrate with a heating area 11 and two connection areas 12, 12'.

In the next step 200, the heating element is formed into a hollow body. To do this, one end of the substrate is bent towards the opposite end of the substrate, so that a gap is created between the edges bent towards one another. As a result, the heating element forms a hollow body and can also be referred to as a tube. The resistance heating structure 20 is arranged on the inside of the hollow body. Optionally, the heating element can also be bent in such a way that the resistance heating structure is arranged on the outside of the hollow body (not shown). When rolled up, the heating element can turn off Figure 7C be plugged into a contacting device.

reference list

1

heating element

10

substrate

11

heating area

12, 12'

connection area

13

metal foil

14

insulation layer

17

joining area

20

resistance heating structure

21

Area of the resistance heating structure

30

connecting cable

60

spring element

70

ceramic element

100

contacting device

Claims (15)

Heating element, having a substrate with a first surface and a second surface opposite the first surface, having at least one heating area and at least one connection area, • wherein a resistance heating structure is arranged on the first surface of the substrate in the heating area, • wherein the at least one connection area is designed as a tab that protrudes from the heating area and • wherein the resistance heating structure has connection lines and these connection lines extend into the at least one connection area or project out of the heating area separately from the at least one connection area. 2. The heating element of claim 1, wherein the heating region and the at least one terminal region of the substrate are molded in one piece. Heating element according to claim 1 or 2, wherein at least one connection area is designed as spring elements. Heating element according to one of claims 1 - 3, wherein at least one connection area is enclosed in a ceramic element. Heating element according to one of claims 1 - 4, wherein at least one connection area has a fastening means. A heating element according to any one of claims 1-5, wherein the substrate is planar or has a curved shape, opposite ends of the substrate being brought towards each other for the curved shape to form a hollow body. A heating element according to claim 6, wherein the edges of the opposite ends gap, abut, overlap or intermesh. Heating element according to any one of claims 1 - 7, wherein the substrate has at least one joining area in addition to the heating area and at least one connection area, which does not contain a resistance heating structure. Heating element according to one of claims 1 - 8, wherein the line cross section of the connection lines is higher than the line cross section of the resistance heating structure. Heating element according to one of claims 1 - 9, wherein the connection lines have contact pads. Method for producing a heating element, in particular having the steps: • Providing a substrate • Placing a resistance ladder structure on the substrate • Cutting the substrate to size while obtaining a heating area and at least one connection area which is in the form of a tab. 12. The method according to claim 11, wherein the substrate is cut in such a way that, apart from the heating area, at least one joining area is obtained. A method according to claim 11 or 12, wherein opposite ends of the heating element are brought together to obtain a hollow body. Electrical device comprising a circuit board, wherein the heating element according to claims 1 - 10 is plugged onto the circuit board in order to electrically contact the circuit board. 15. The electrical device of claim 14, wherein the electrical contacting is accomplished without wires or cables.

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