WO2020244944A1 - Method for manufacturing a heating element, heating element, and use of the heating element - Google Patents

Abstract

The invention relates to a method for manufacturing a heating element (10) composed of an electrically conductive elastomer (14), a first contact (18), and a second contact (20). Firstly, an adhesion promoter is applied to the contacts (18, 20) or mixed with the electrically conductive elastomer (14). Subsequently, the contacts (18, 20) are placed in a casting mould (12), then the casting mould (12) is filled with the electrically conductive elastomer (14). A physical/chemical bond is created by the adhesion promoter between the conductive elastomer (14) and the contacts (18, 20), and a composite composed of the conductive elastomer (14) and the contacts (18, 20) and having elastic properties is formed. Finally, the heating element (10) is shaped by injection moulding, pressing, and/or transfer moulding. The invention also relates to a heating element (10) having elastic properties which is designed with a planar shape (16) or an annular shape (58), and to the use of the heating element (10).

Description

Method for manufacturing a heating element, heating element and use of the heating element

Disclosure of the invention

The invention relates to a method of making a

Heating element made of an electrically conductive elastomer with a first and a second contact, as well as a heating element and the use of the heating element.

State of the art

DE 10 2016 206250 A1 relates to an electrical heating device for a supply tank of a vehicle. The electrical heating device comprises at least one electrically conductive heat conducting body and at least one electrical heating element, wherein the heating element lies flat against the at least one heat conducting body. The heat conducting body is connected to or can be connected to an electrical voltage source. Between the

A soft heat conducting medium is arranged on the heating element and the heat conducting body. It is a thermal paste, a

Thermal fluid or a thermal pad or adhesive.

US 3,900,654 relates to an electrical heating element with a polymer. The electric heating element is thin, flexible and robust and safe in the

Use and includes an arrangement of layers in which a film of electrically insulating polymeric material is in contact with at least one side of a layer of electrically conductive elastomeric material composed of a blend of a fluoroelastomer with conductive carbon black. The arrangement comprises a suitable conducting element, for example a strip made of copper or of aluminum in contact with a voltage supply.

EP 0820 214 A1 relates to a self-regulating electrical heating element for heaters shaped as a tube or cartridge. The heating element has a cylindrical or prismatic outer shape and can be inserted into a cartridge or a cavity of the device to be heated. It includes an arrangement of self-regulating electrical conductors (PTC elements), which are made of a composite material with a polymer matrix. One

Resistance section generates heat through the Joule effect. Furthermore, there is an electrode system which distributes the electrical current, in particular a trendy resistor arrangement, and to a core which is made of insulating material. This holds the resistor assembly and the electrodes in position with respect to one another.

DE 10 2012 212 798 A1 relates to a heating element with at least a thermoelectric heater. The heating element is at least partially formed with a conductive material and can be supplied with electrical energy via at least two conductor tracks. The conductor tracks are made using a thermal

Spraying method, in particular formed by plasma spraying according to DIN 659.

For heating bodies or media such as gas or

Liquid, a wide variety of heating elements are used, for example ceramic PTC heating elements with metallic resistance heating or resistance heating based on electrically conductive plastics, such as are known from DE 10 2012 212 798 A1.

Heating elements can also be produced on the basis of elastomer materials, for example according to EP 0 820 214 A1. However, the application of the electrodes according to these solutions is not to be regarded as solved. Simply mounting electrodes on resistance conductors, in which the heat is generated, is not sufficient. Purely mechanical application to the surface is not sufficient; there is no constant contact resistance. Seen over the service life, settling processes occur which result in a change in the total resistance and thus in the performance of the heating element. This change in overall resistance is also accelerated by frequent temperature changes.

Presentation of the invention

According to the invention, a method is presented for producing a

Heating element made of an electrically conductive elastomer, a first contact and a second contact, with the following process steps being carried out: a) Adding an adhesion promoter to the electrically conductive elastomer or applying an adhesion promoter to contact surfaces,

b) placing at least two contacts in a mold,

c) Pouring the mold with the electrically conductive elastomer, d) Creation of a physical / chemical connection by the adhesion promoter between the electrically conductive elastomer and the contacts and formation of a composite of conductive elastomer and the contacts with elastic properties and, e) Shaping the heating element by injection molding, pressing and / or transfer molding.

Due to the molding of the electrically conductive elastomer in the mold, it can optimally adapt to the contacts. In addition, the electrically conductive elastomer contains at least one adhesion promoter so that it can also be chemically bonded to the contacts, or the adhesion promoter is at least partially applied to the contact surfaces in advance. By using the elastomers, they will not become detached from the contacts under mechanical deformations or expansions that are caused by thermal heating, so that a good electrical contact resistance is provided over the service life.

In a further development of the method proposed according to the invention, electrically conductive elastomers such as thermoplastic elastomers (TPE) EPDM, NBR, WR, NR, SBR, HNBR, fluororubber or silicone rubbers are used, and conductive fillers such as graphite, carbon fibers, carbon black, metal particles, metal fibers and / or carbon nanotubes are used .

In the method proposed according to the invention, the specific electrical resistance of the electrically conductive elastomer is between 0.001 W cm and 500 W cm, preferably in the range between 0.1 W cm and 100 W cm.

In the method proposed according to the invention, the contacts are cast into the conductive elastomer while maintaining a constant distance over their length. This ensures that at homogeneous distributed fillers within the electrically conductive elastomer heat is developed evenly over the heating surface.

In the method proposed according to the invention, the contacts can be encapsulated by the electrically conductive elastomer on one side, more than one side or completely.

In an advantageous manner, exposed points can be produced in the area of the contacts in the heating element, so that the contacts can be easily fixed.

In the method proposed according to the invention, isolated parts of the contacts are fixed in one length on an insulating substrate. The insulation remaining on the contacts is provided with an insulation layer so that a heating element that is completely electrically insulated from the outside is obtained.

In a further development of the method proposed according to the invention, insulation of the contacts can be melted and the heating element, which is, for example, flat, can be sealed with an insulation layer.

The heating element with elastic properties obtained according to the method proposed according to the invention is characterized in that it can be designed in a planar shape or also in a ring shape. The contacts are for example stripped parts, i. Cable ends or stamped grids or metal strips or the like freed from their insulation sheathing.

For example, the metal strips or lead frame can be crimped,

Have soldering surfaces and / or adhesive surfaces, so that a connection with other components can be easily established.

The heating element proposed according to the invention can be, for example, a rod heating element or a heating cartridge or a handle heating element, with rolled-up heating elements, which have previously been flat, are inserted into an insulating sleeve, the cavity of which is filled with a filling of compacted ceramic or mineral powder. The heating element proposed according to the invention is deformed, for example, in such a way that it forms a rod element, can be used on a plastic sleeve made of PPS, PA or PPA and, if an insulation layer is provided, a metallic sleeve can also be used.

When an insulating layer is formed, it can be formed as an insulating seal or a thin film, preferably a PI film, can be used instead of this.

The invention also relates to the use of the

Heating element designed as a DNOx heating element as a flat

Tank heating element or as a conveyor module heating element, as a handle heating element, water heater, aquarium heating element, heating cartridge, surface heating element, heating sleeve for batteries, seat heating, interior heating, heating elements for containers such as rice cookers or camping stoves or the like.

Advantages of the invention

The solution proposed according to the invention is characterized in that an improved connection of the contacts or electrodes and the electrically conductive elastomer material is achieved. The improvement of the contact results in particular from the primary shaping of the elastomer, since this constantly encloses contacts or electrodes within the casting mold and an optimal molding can be achieved. A chemical and physical connection between the contacts or electrodes, on the one hand, and the electrically conductive elastomer, on the other hand, is supported by adding or applying an adhesion promoter.

Plasma pretreatment of the contacts or electrodes considerably improves the adhesion of the electrically conductive elastomer to the contacts. The adhesion promoter can be applied as a primer to the contact surfaces partially or on all sides or, as already mentioned above, be mixed into the electrically conductive elastomer material.

Due to the use of elastomer material that has a high elongation at break, this is also not caused by mechanical deformation or expansion by thermal heating Detach contacts or electrodes, but follow every movement. This elasticity allows the contact to be maintained and thus a good electrical contact resistance of the elastomer, which is electrically conductive and can be used as a heating resistor, can be maintained over the service life of the heating element proposed according to the invention.

The contacts or electrodes used, which are encapsulated by the electrically conductive elastomer, can be encapsulated by the latter on one side or more than one side or completely. Support points can be formed which serve to fix the contacts or the electrodes within the mold and which are still exposed.

The contacts of the heating element proposed according to the invention

or electrodes can, for example, from their

Insulation sheath be stripped cable ends, i. Stripped cable ends, punched grids, structured or provided with holes, or metallic strips. Advantageously, cables and metallic strips are flexible

Properties, so that the elastic heating element according to the invention remains elastic overall as a composite and, for example, as a seat heater in

Seat pad can be developed. During its shaping, the elastomer penetrates between the strand of the stripped cable or in the static grids inserted in structures or holes. By the invention

The proposed solution is to produce heating elements to which the electrically conductive elastomer material and which the contacts are chemically and / or physically connected to one another via the adhesion promoter.

After the production of the heating element, it can still be deformed, for example shaped as a rod heating element or used as a heating cartridge. Inserted into an insulating sleeve, the rolled-up heating element can be mounted against the inner diameter of the sleeve. The re-deformation of the elastomer causes the rolled-up heating element to attach itself to the inner diameter of the sleeve. The sleeve is then filled with insulating material, preferably ceramic or mineral powder, so that the elastic heating element is pressed against the sleeve from the inside. In further design variants, the rod heating element can be equipped with a

Plastic sleeves made from PPS, PA or PPA, for example. It is also possible to use sleeves other than plastic sleeves, for example metallic sleeves, if an insulation layer is provided between the metallic sleeve on the one hand and the heating element on the other. This can be, for example, an insulating coating or a thin film, if possible a high-temperature-resistant PI film. To mount the heating elements, fixing elements such as

Breakthroughs, elevations, ribs or grooves in the electrically conductive

Be molded elastomer. These fixing elements can be within the

Heating element surface, laterally or outside of the heating element surfaces beyond the contacts are formed.

Brief description of the drawings

Embodiments of the invention are explained in more detail with reference to the drawings and the following description.

Show it:

Figure 1 is a plan view of a surface heating element, which is contacted via cable,

Figure 1.1 shows a section according to 1.1-1.1 in Figure 1

Figure 2 shows a surface heating element, which is contacted via a cable with a

Insulation layer,

Figure 2.1 shows a section according to ll.l-ll.l in Figure 2,

Figure 2.2 shows a section according to II.2-11.2 in Figure 2,

Figure 3 shows a flat heating element with ring-shaped encapsulated contacts, Figure 3.1 is a side view of the same,

FIG. 4 shows a flat heating element contacted by a stamped grid, Figure 4.1 a flat heating element contacted via metal strips,

FIG. 5 shows a flat heating element contacted via metal strips,

Figure 5.1 shows a section according to V.l-V.l in Figure 5,

Figure 5.2 shows a section according to V.2-V.2 according to Figure 5,

FIG. 6 shows a heating element configured in a ring shape,

Figure 6.1 shows a section through the ring-shaped heating element according to Figure 6,

FIG. 7 a rod-shaped heating element with a rounded tip,

Figure 7.1 is a section through the rod-shaped heating element according to Figure 7,

Figure 8 shows a rod heating element as a heating cartridge and

Figure 8.1 shows a cross section through the rod heating element as a heating cartridge according to

Figure 8

Embodiments of the invention

Figure 1 shows a plan view of a heating element 10, which has a first contact 18 and a second contact 20, which are designed here as stripped parts 24 of cables. The heating element 10 in the plan view according to FIG. 1 has a planar shape 16 and is accordingly flat. An insulation 22 of the contacts 18, 20 is removed from the contacts 18, 20 over a length 28. As from FIG. 1.1, which shows the section path 1.1-1.1 according to FIG. 1, the conductive elastomer 24 between the two contacts 18 and 20 has a uniform thickness 26. Due to the fact that the contacts 18 or 20 placed in a casting mold 12 are encapsulated by the electrically conductive elastomer 14, there is a particularly intimate physical / chemical bond between the material of the electrically conductive elastomer 14 on the one hand and the metallic material of the first contact 18 as well of the second contact 20 on the other hand. The illustration according to FIGS. 1 and 1.1 show the planar shape 16 of the heating element 10, which can be shaped or deformed in different design variants by further operations such as pressing, rolling and the like, as will be described in more detail below.

Figure 2 shows another embodiment of the invention

proposed heating element 10.

From the top view according to FIG. 2 it can be seen that the heating element 10 - also in planar form 16 - is covered by a first insulation layer 25. The 1st insulation layer 25 covers both the first contact 18 and the second contact 20 according to their stripped parts 24 and the flat, electrically conductive elastomer 14. The 1st insulation layer 25 also covers the insulation 22 and parts of a remaining insulation 36 from Cable ends that form the first contact 18 and the second contact 20, respectively. The two contacts 18, 20 are arranged at a constant distance 34 as seen over their length 28. Maintaining the constant distance 34 between the two contacts 18 and 20 has the effect that, in the case of fillers homogeneously distributed in the electrically conductive elastomer 14, heat is developed evenly over the heating element surface.

It can be seen from FIG. 2 that closed, completely insulated heating elements 10 can be formed, designed in planar form 16 and covered by the 1st insulation layer 25. By melting on the insulation 22 when pouring over the heating element 10, the insulation material, the 1st insulation layer 25 the heating element 10 is sealed with a chemically compatible material.

From the top view according to FIG. 2 it can be seen that in the area of the first contact 18 or the second contact 20 there are exposed locations 32 near the stripped areas 24. These serve as support points for fixing the contacts 18 or 20 on an insulating substrate 30.

Figures 2.1 and 2.2 show the sections ll.l-ll.l and 11.2-11.2, as they are entered in FIG. The cutting course ll.l-ll-l according to FIG 2.1 shows a section through the heating element 10 according to FIG. 2 in the area of the exposed points 32. The 1st insulation layer 25 covers the electrically conductive elastomer 14 and the contacts 18 and 20, respectively.

FIG. 2.2, which corresponds to a section II.2-11.2 according to FIG. 2, shows that the contacts 18, 20 are covered by the 1st insulation layer 25, as is the electrically conductive elastomer 14.

Figure 3 shows a further embodiment of the invention

proposed heating element 10, in which the contacts 18, 20 are encapsulated in an annular shape 38. The plan view according to FIG. 3 shows that the two contacts 18, 20 each have a jacket 40 which, in the sectional view in FIG. 3.1, encloses it in the form of a jacket 40. Between the two

The electrically conductive elastomer 14 with an upper side 44 and an underside 46 runs in planar form 16 to contacts 18 and 20, respectively. The electrically conductive elastomer 14 between the two contacts 18

and 20 a surface 42, respectively. According to FIG. 3, one end of the heating element 10, which is embodied in planar form 16, is formed by insulation 22 still on the contacts 18 and 20, respectively.

In the representations according to Figures 4 and 4.1, heating elements 10 are shown, which either by punched grid 50 according to Figure 4 or by

Metal strips 48 are electrically contacted. In both cases, the heating element 10 according to the invention, designed in planar form 16, comprises the electrically conductive elastomer 14 between the first contact 18 and the second contact 20 - designed as a surface 42. In the variant embodiment according to FIG Metal strips 48 are provided, which are connected to a first connection point 52 and a second connection point 54. In both embodiment variants according to FIGS. 4 and 4.1 of the heating element 10 embodied in planar form 16, the latter is very flat.

FIG. 5 shows the plan view of a heating element 10 according to the invention in planar form 16, the contacts 18 and 20 of which are designed as a lead frame 50. The two leadframes 50 are at the first connection point 52

or the second connection point 54, or electrically connected to wire ends which are still provided with a remaining insulation 36 crimped. The surface 42 of the heating element 10 extends between the two stamped grids 50, which run essentially parallel to one another, as seen here from the upper side 44.

FIG. 5.1 shows the section line V.l-V.l entered in FIG. 5, while in the illustration according to FIG. 5.2 a section line V.2-V.2, as entered in FIG. 5, can be seen.

In the illustration according to FIG. 5.1, exposed points 32 can be seen which are located both on the upper side 44 and on the lower side 46 of the surface 42 of the heating element 10 in planar form 16. In the illustration according to FIG. 5.2 it can be seen that the two leadframes 50 extending essentially parallel to one another have a rectangular cross section 56.

FIG. 6 shows a heating element 10 which is designed in an annular shape 58. By means of a simple bending or rolling process, the planar shape 16 described above with reference to FIGS. 1 to 5.2 can be obtained

Reshape heating elements 10 into heating elements 10 in ring shape 58. In the

6, the first contact 18 and the second contact 20 are opposite one another - a non-closed ring shape is shown. The material of the electrically conductive elastomer 14 of the heating element 10, which is shaped in a ring shape 58, is mounted on an inner sleeve 62. The heating element 10 including the inner sleeve 62 is inserted into an insulating sleeve 60 or overmolded with an insulating material. The first contact 18 and the second contact 20 run in the plane of the drawing according to FIG. 6.

Figure 6.1 shows that the material of the electrically conductive elastomer 14 between the outside of the inner sleeve 62 and the inside of the

Isolation sleeve 60 is added. The electrically conductive elastomers 14 used are preferably thermoplastic elastomers, EPDM, NPR, NR, SBR, HNBR, fluororubbers, silicone rubbers and the like, which contain conductive fillers such as graphite, carbon fibers, carbon black, metal particles, to achieve their electrical conductivity. Have metal fibers and carbon nanotubes. The specific electrical resistance of the electrically conductive elastomers 14 in each case in order to function as heating elements 10 is between 0.01 W cm and 500 W cm, preferably between 0.1 W cm and 100 W cm. A rod heating element 74 emerges from FIGS. 7 and 7.1.

It can be seen from FIG. 7 that a heating element 10 embodied, for example, in a planar shape 16 is transformed into a rod heating element 74 according to FIG

or can be deformed. FIG. 7 also shows that the original heating element 10, which has a planar shape 16, the area made of electrically conductive elastomer 14, is inserted into the insulating sleeve 60 or a sleeve 64, be it made of plastic material or made of elastic material. The two into the

Contacts 18 and 20 extending in the drawing plane according to FIG. 7.1 lie opposite one another and the ring shape 58 is not completely closed, and a gap remains between the first contact 18 and the second contact 20. The electrically conductive elastomer 14 rests against the inner wall of the insulating sleeve 60 or the sleeve 64 that surrounds it. A cavity 78, which results when the planar heating element 10 originally had a planar shape 16, is filled with an insulating, preferably ceramic, mineral, powder that serves as a filling 80. As a result, the elastic heating element 10 is in the form of the surface 42 made of electrically conductive elastomer 14 and the two contacts 18, 20

pressed apart and against the inside of this surrounding

Insulation sleeve 60 or the sleeve 64 pressed. A press contact can only be made after the cavity 78 has been completely filled and the filling 80 has been compressed. While that shown in Figure 7

Rod heating element 74 has a rounded dome, the behavior of the heating cartridge 76, which is shown in FIGS. 8 and 8.1, is somewhat different. In contrast to the rod heating element 74 shown in FIG. 7, the heating cartridge 86 according to FIG. 8 has a flat end face. The interior of the heating cartridge 76 essentially corresponds to the interior of the

Rod heating element 74, as shown in Figures 7 and 7.1.

In the case of the heating cartridge 76, too, this is originally a planar shape 16

having heating element 10, the first contact 18, the second contact 20 and the surface 42 made of electrically conductive elastomer 14 are introduced into the insulating sleeve 60. The insulating sleeve 60 can be a sleeve 64 made of either plastic or material metallic material is made. When the sleeve 64 is produced from metallic material, a second insulation layer 66 or an insulating coating 68 or the introduction of a film 70, preferably a temperature-resistant PI film 72, must be ensured.

In the case of the heating cartridge 76 shown in longitudinal section in FIG. 8, the cavity 78 is created in the geometry shown, which is formed by a filling 80

is preferably filled from ceramic, mineral powder. The filling 80 ensures that the composite of electrically conductive

Elastomer 14 and the two laterally running contacts 18

or 20 is pressed against the inside of the insulating sleeve 60 surrounding this composite or the sleeve 64, cf. also representation according to Figure 8.1. The cross section shown in FIG. 8.1 through the heating cartridge 76 according to FIG. 8 essentially corresponds to the cross section as shown in FIG. 7.1 in relation to the rod heating element 74. The two mutually opposite contacts 18 and 20 run in the plane of the drawing according to FIG. 8.1 - analogous to the illustration according to FIG. 7.1 in relation to the rod heating element 74.

Here, too, the ring shape 58 is not completely closed, between the first contact 18 running in the plane of the drawing and the second contact 20, seen in the circumferential direction, a gap remains.

With reference to Figures 7 and 8, the variants of the

Heating element 10 according to the invention as a rod heating element 74 or as a heating cartridge 76, it should be noted that the insulating sleeve 60

or the sleeve 64 can be made of metallic material or, in the case of a plastic sleeve, of PPS, PA or PPA.

The heating elements 10 proposed according to the invention, be they in planar form 16, be they in ring form 58, be they rod heating elements 74, be they heating cartridges 76, be it handle heating elements or the like, can be used as DNOx heating elements for flat tank heating elements or

Delivery module heating elements are used for exhaust aftertreatment systems. They can also be used as grip heating elements,

Use continuous heating elements, aquarium heating elements, surface heating elements, as well as heating jackets for batteries, seat heating or interior heating use. Another field of application is in the area for containers such as rice cookers or camping stoves or the like.

The invention is not restricted to the exemplary embodiments described here and the aspects emphasized therein. Rather, it is within the by the

Claims specified range, a variety of modifications are possible, which are within the scope of professional action.

Claims

Expectations 1. A method for producing a heating element (10) from a electrically conductive elastomer (14), a first contact (18) and a second contact (20) with the following process steps: a) Adding an adhesion promoter to the electrically conductive Elastomer (14) or orders of an adhesion promoter Surfaces of contacts (18, 20), b) placing at least two contacts (18, 20) in a casting mold (12), c) Pouring out the casting mold (12) with the electrically conductive one Elastomer (14), d) Creation of a physical / chemical connection by means of an adhesion promoter between the conductive elastomer (14) and the contacts (18, 20) and formation of an elastic one Properties exhibiting composite made of conductive Elastomer (14) and the contacts (18, 20) and, e) shaping of the heating element (10) by injection molding, Pressing and / or transfer molding. 2. The method according to claim 1, characterized in that the Electrically conductive elastomer (14) contains thermoplastic elastomers EPDM, NBR, WR, NR, SBR, HNBR, fluororubber or silicone rubber as the base material, as well as conductive fillers such as graphite, Carbon fibers, conductive black, metal particles, metal fibers and / or Includes carbon nanotubes. 3. The method according to claim 1, characterized in that the specific elastic resistance of the electrically conductive elastomer (14) is between 0.001 W cm and 500 W cm, preferably between 0.1 W cm and 100 W cm. 4. The method according to claim 1, characterized in that the Contacts (18, 20) maintaining a constant distance (34) be poured into the conductive elastomer (14) over its length (28). 5. The method according to claim 1, characterized in that the Contacts (18, 20) are encapsulated by the electrically conductive elastomer (14) on one side, more than one side or completely. 6. The method according to claim 1, characterized in that im Heating element (10) exposed locations (32) in the area of the contacts (18, 20) for fixing the same. 7. The method according to claim 1, characterized in that stripped parts (24) of the contacts (18, 20) are fixed in a length (28) on an insulating substrate (30) and with a remaining insulation (36) with a 1. Insulation layer (25) are provided. 8. The method according to claim 7, characterized in that a Insulation (22) of the contacts (18, 20) is melted and a seal between the heating element (10) and the 1st insulation layer (25) is produced. 9. Heating element (10) with elastic properties, produced according to one of claims 1 to 8, characterized in that it is designed in a planar shape (16) or in an annular shape (58). 10. Heating element (10) according to claim 9, characterized in that the contacts (18, 20) are stripped parts (24) of cables, stamped grids (50) or metal strips (48). 11. Heating element (10) according to claim 10, characterized in that the lead frame (50) or the metal strips (48) have crimping points, soldering points and / or adhesive surfaces. 12. Heating element (10) according to claim 9, characterized in that the heating element (10) is deformed into a rod heating element (74) or a heating cartridge (76) or a grip heating element, and the heating element (10) is in an insulating sleeve (60 ) is inserted, the cavity (78) with a filling (80) made of ceramic or mineral powder is filled. 13. Heating element (10) according to claim 12, characterized in that the rod heating element (74) has a sleeve (64) made of plastic material, such as PPS or PA or PPA, or - if a second insulation layer (66) is provided - a sleeve ( 64) made of metallic material. 14. Heating element (10) according to claim 9, characterized in that the insulating layer (66), which is designed as an insulating coating (68) or as a film (70), in particular as a PI film (72). 15. Use of the heating element (10) according to one of claims 8 to 14 as a heating element (10) in exhaust gas aftertreatment systems for heating / for thawing storage tank heating elements Stocking of an operating / auxiliary material, in particular a freezable urea water solution or as a conveyor module heating element, or as a handle heating element or as a flow heater or as Aquarium heating element, or as a heating cartridge (76) or as Surface heating element or as a heating jacket for batteries or as seat heating or as interior heating or as heating elements for containers such as rice cookers or camping stoves.