Heating device comprising a temperature measuring device and method for temperature measurement at a heating device and for manufacturing

Abstract

A heating device comprising a temperature measuring device, having a sheet-like carrier, at least one heating conductor on the sheet-like carrier, an elongated electrode on the sheet-like carrier and a layer structure on the carrier, wherein an insulating layer is between the heating conductor and the electrode. A measuring device for detecting local high temperatures at the heating device is connected to the electrode and the heating conductor. The measuring device detects a temperature-dependent leakage current through the insulating layer between the heating conductor and the electrode and evaluates it as a measure of local temperature changes at the heating device. The electrode is composed of a material whose temperature dependence of the electrical resistance in the temperature range between 0 °C and 200 °C is between 0.0005 / °C and 0.01 / °C. The temperature measuring device is connected to the electrode to measure the temperature at the electrode using the temperature dependence of the electrode resistance.

Description

Technical Field

[0001] The present invention relates to a heating device, the heating device including a temperature measuring device for the heating device, and a method for measuring temperature at such a heating device, and also to a method for manufacturing such a heating device. Background Technology

[0002] A heating device with a temperature measuring apparatus is known from EP 3145273B1. The heating device has a sheet-like carrier, a heating conductor, and conductive connection areas in the form of electrodes, wherein a dielectric layer is provided between the two. Here, a temperature-dependent leakage current through this dielectric layer can be detected by means of a measuring device and evaluated as a measure of the local temperature change at the heating device. However, experience has shown that such local temperature changes only occur near or directly at the heating conductor. Furthermore, they essentially measure the temperature affected by the heating conductor. Summary of the Invention

[0003] The present invention is based on the following objective: to provide a heating device and a method for measuring temperature using the heating device, as well as a method for manufacturing the heating device of the type mentioned at the beginning, and to solve the problems of the prior art by means of the heating device and the method, and in particular to advantageously manufacture or construct such a heating device, and to advantageously detect the temperature at the heating device.

[0004] This objective is achieved by a heating device having the features of claim 1, by a method for measuring temperature at such a heating device having the features of claim 19, and by a method for manufacturing such a heating device having the features of claim 21 or 23. Advantageous and preferred improvements of the invention are the subject of the other claims and will be explained in more detail below. In doing so, some features will be explained only with respect to the heating device itself or only with respect to one of the methods. However, in any case, they are intended to be applicable autonomously and independently of each other to one of the methods and to the heating device. The wording of the claims is incorporated herein by express reference.

[0005] The specification specifies that the heating device has a sheet-like carrier and at least one heating conductor on the sheet-like carrier, wherein the heating conductor may optionally have multiple local heating conductors or may be divided into multiple such local heating conductors. Furthermore, elongated electrodes are provided on the sheet-like carrier, wherein either only a single elongated electrode may be provided, or at least one additional additional electrode may be further provided. A layer structure is provided on the carrier, wherein an insulating layer is provided between the heating conductor and the electrode. This insulating layer advantageously has dielectric properties, as known from the prior art itself. Furthermore, a measuring device for detecting localized high temperatures at the heating device is provided, the measuring device being connected to the electrode and the heating conductor. The measuring device is designed to detect a temperature-related leakage current through the insulating layer between the heating conductor and the electrode, which may be in the range of several mA. This temperature-related leakage current is assessed as a measure of the localized temperature or temperature change at the heating device. This mechanism is known in principle from the prior art, and reference has been made to the prior art in this regard, thus unnecessary repetition can be omitted here. In this way, particularly high temperatures can also be identified first, and countermeasures can be taken to prevent damage to the heating device or electrical equipment including the heating device from said particularly high temperatures.

[0006] According to the invention, the electrode itself is constructed of a material having a temperature dependence of its resistance, such that the electrode itself can be directly used for temperature measurement. Therefore, the electrode not only conducts current as a signal, but also, in effect, acts as a sensor to detect temperature. For this purpose, the temperature dependence of the electrode material's resistance is between 0.0005 / ℃ and 0.01 / ℃, or between 0.000500 = 500 ppm / K and 10,000 ppm / K, particularly in the temperature range of 0℃ to 500℃ relative to room temperature as a reference. Furthermore, a temperature measuring device is connected to the electrode or its end or connector to measure the temperature at the electrode using the temperature dependence of the electrode's resistance. This temperature measurement based on temperature-dependent resistance is also well known to those skilled in the art and can be implemented according to this prior art. A particular feature of the invention is that the electrode used for temperature detection based on leakage current now also functions as a temperature sensor due to its particularly provided temperature-dependent characteristics.

[0007] In an improvement of the invention, the temperature dependence of the resistance of the electrode or electrode material can be between 0.0015 / ℃ and 0.005 / ℃, or between 0.0015 = 1,500 ppm / K and 5,000 ppm / K, particularly advantageously at about 0.0035 / ℃ or 0.0035 = 3,500 ppm / K, within the temperature range of 0℃ to 200℃. The temperature-dependent resistance of the electrode can thus be determined, and the temperature can be precisely determined from the corresponding resistance or the change in said resistance.

[0008] Precious metals, such as silver, palladium, platinum, gold, or ruthenium, can be advantageously used in electrodes. In addition, electrode materials exhibiting the PTC / NTC effect are also widely used.

[0009] In one improvement of the invention, the electrode may be at least partially covered or overlapped by the heating conductor, particularly with respect to its projection onto the plane of the carrier. This carrier is typically very advantageously a flat or planar design, but it may also be curved or tubular; in particular, the structure of the functional layer may be disposed on the outside of the tube. An insulating layer extends between the heating conductor and the electrode, wherein the insulating layer advantageously has a larger or much larger surface area than the area covered by the heating conductor and / or the electrode. It may also be specified that segments of the electrode extend along the longitudinal extent of the heating conductor, and in doing so, are similarly covered or overlapped by the heating conductor. In particular, the electrode or segment of the electrode may extend along at least 70% or 90% of the longitudinal extent of the heating conductor, allowing temperature monitoring of the heating conductor in this area. The electrode or segment of the electrode advantageously extends along the entire longitudinal extent of the heating conductor, allowing temperature monitoring along the entire heating conductor. Thus, maximum safety can be achieved to prevent damage to the heating device due to excessively high temperatures of the heating conductor.

[0010] In an improvement to the invention, the electrode can have a width small compared to its length. For example, the length can be at least twenty times the width, preferably at least fifty times the width. Therefore, the electrode requires relatively little electrode material, which is typically expensive. Furthermore, this relatively small width of the electrode is sufficient for tasks involving the detection of leakage current through the insulating layer to the heated conductor. A small conductor cross-section can be advantageous for direct temperature measurement using the electrode.

[0011] The insulating layer can advantageously have a resistance between the top and bottom sides or between the heating conductor and the electrodes, which is at least 1 MΩ in a temperature range from 100°C to 150°C. Advantageously, this can even be at least 10 MΩ. At a specific temperature, the resistance may drop sharply, which is considered initially critical for the heating device in terms of localized temperature rise. Therefore, the material composition can be selected for this purpose. However, this is known in principle from the aforementioned prior art.

[0012] In an improvement to the invention, the overall resistance of the electrodes, that is, the overall resistance between the two electrode connectors, can be specified to be between 50 Ω and 100 kΩ in the temperature range between 0°C and 500°C. In particular, the resistance of the electrodes can be between 5 kΩ and 20 kΩ in this temperature range. The variation of this resistance with or with temperature has been described above.

[0013] To accurately and reliably assess temperature, the electrode can be specified to have a constant width along its longitudinal direction. By varying the profile of the electrode rails, particularly through curved and / or straight segments, specific areas can be assessed more precisely. The electrode thickness should also be constant, especially to improve electrode production capabilities. The width can range, for example, from 0.05 mm to 2 mm, and the thickness can be between 3 μm and 1 mm. Furthermore, the design of series circuits with different electrode rail geometries is possible. One embodiment could be, for example, a series circuit including an electrode network and sensor electrodes. This has the advantage that the location of hot spots can be determined by evaluating both leakage current and resistance measurements.

[0014] Preferably, the width of the heating conductor is significantly greater than its length, and also greater than the electrode in an absolute sense. In particular, the heating conductor can be five to one hundred times wider than the electrode, especially five to one hundred times wider than the electrode overlapped by the heating conductor. The above-described combination of electrode network and sensor electrode is also advantageously possible here.

[0015] In another improvement of the invention, the electrode material may be specified to have a variable temperature coefficient of resistance, advantageously a PTC material. Therefore, at very high temperatures, it is possible that not much current can flow through the electrode during temperature measurement.

[0016] In an advantageous improvement of the invention, the heating device may be configured to have multiple heating conductors or multiple local heating conductors. These may, for example, and advantageously, be interconnected with each other in a series circuit. Parallel circuits, as well as combinations of series and parallel circuits, are theoretically possible. Each local heating conductor preferably covers an electrode or electrode section, particularly with the aforementioned advantageous pre-defined coverage of at least 80% or 90%, especially 100%. The individual local heating conductors may be connected to each other by means of connecting sections, particularly to avoid bending or curvature of the local heating conductors themselves. These are disadvantageous in terms of current conduction for known reasons. Although electrodes or electrode sections may be disposed in the regions of these connecting sections, it is not necessarily required. However, the profile of the electrodes advantageously follows the profile of the heating conductors. The resistance of the connecting sections should be significantly lower than the resistance of the heating conductor material, advantageously at most 1 / 10 of it.

[0017] In an improvement to the invention, it can be specified that at least one additional electrode is made of the same material as the electrode to be provided. This additional electrode is also used for temperature measurement, but it is not covered or overlapped by the heating conductor. Preferably, a lateral distance is provided between the additional electrode and the heating conductor or each heating conductor in the surrounding area, which is twice the width of the electrode rail, or at least 1 mm, or even at least 2 mm, advantageously at least 10 mm. Thus, the temperature at the additional electrode can be primarily or even solely affected by the carrier or the medium adjacent to the carrier or the medium contained in the carrier (e.g., water). Temperature measurement at the additional electrode is advantageously performed by the change in its resistance relative to temperature, that is, as in the case of the electrode, as already described above. Therefore, the additional electrode is also connected to the same temperature measuring device as the electrode covered or overlapped by the heating conductor.

[0018] The heating device can advantageously be provided with the following layered structure. A covering layer or carrier insulation layer can be applied to the carrier, which can be made of ceramic or preferably of metal or steel. At least one electrode, preferably all electrodes or electrode sections, particularly including the aforementioned additional electrodes, is applied to the carrier insulation layer. An insulation layer according to the invention, through which leakage current can flow in the event of localized overheating, is then applied to the electrodes, multiple electrodes, or electrode sections. Heating conductors, or all heating conductors and localized heating conductors, are sequentially applied to the insulation layer. A covering layer is then applied to the outside of the heating conductors, multiple heating conductors, or localized heating conductors, particularly to protect the heating conductors from the atmosphere or oxygen, i.e., primarily from oxidation. Electrical contact is formed with the electrodes and heating conductors in a known manner, particularly by means of the electrodes and heating conductors that are not covered by the corresponding insulation layer in the lateral direction.

[0019] Alternatively, the sequence could be: carrier, carrier insulating layer or dielectric layer, heating conductor, insulating layer or dielectric layer, (one or more) electrodes, capping layer.

[0020] In the method according to the invention for measuring temperature at such a heating device, temperature measurement is specified in two different ways. First, temperature detection is performed by means of a temperature-dependent leakage current flowing through the insulation layer between the heating device and the electrodes. In this process, it can be determined, in particular, that if this leakage current flows to a significant degree, there is an excessively high local temperature. Second, temperature measurement at the heating device is performed by measuring and determining the temperature change at the electrodes solely by means of the temperature-dependent resistance of the electrodes. For this purpose, a control device for the heating device or a control device for the heating device can be provided, in which the assessment occurs as a change in temperature over time.

[0021] In a first general method for manufacturing the aforementioned heating device according to the invention, the heating device has a plurality of heating conductors. These plurality of heating conductors may also be a plurality of the aforementioned local heating conductors. All heating conductors of the heating device, and possibly all local heating conductors, are applied in the same method portion or the same method step and are applied by the same heating conductor material. If this is performed in multiple steps, it is also performed in the same manner for all heating conductors or local heating conductors.

[0022] In the second method for manufacturing a heating device according to the invention, as described above, the heating device has multiple electrodes. In particular, the aforementioned additional electrodes are also provided. All electrodes or electrode segments, especially all electrodes or electrode segments including the aforementioned additional electrodes, are applied in the same method steps and by the same electrode material. Similar to the method described above for heating conductors, this also occurs in the same manner for all electrodes or electrode segments and for any additional electrodes that may be provided, even when multiple layers of electrode material are applied.

[0023] These and other features are available not only from the claims but also from the specification and drawings, wherein each feature may be implemented in each case, either on its own or in sub-combinations, in embodiments of the invention and other fields, and may constitute advantageous and inherently protectable embodiments, which are claimed herein. The subdivision of this application into subheadings and individual sections does not limit the general validity of the statements made below. Attached Figure Description

[0024] Exemplary embodiments of the present invention are schematically illustrated in the accompanying drawings and will be explained in more detail below:

[0025] Figure 1 A plan view of a first improved heating device according to the present invention, comprising a sheet-like heating conductor and a zigzag electrode, is shown.

[0026] Figure 2 It shows the through Figure 1 The cross-section of the heating device in the middle, the heating device having a layered structure, and

[0027] Figures 3 to 6 It shows something similar to Figure 1 Various variations of the heating device, which have different improvements to the heating conductor and electrodes. Detailed Implementation

[0028] Figure 1 A plan view of a heating device 11 according to the present invention is shown. Here, the heating device has a rectangular shape, but it can also have any desired shape. In addition to the planar improvement of the heating device 11, curved and tubular heating devices are also conceivable. In particular, the heating device 11 is manufactured using thick film technology.

[0029] The heating device 11 has a carrier 12 made of electrically insulating ceramic or metal. The layered structure is located on the top side 13 of the carrier, and if the carrier 12 is made of metal, a functional insulator 27 is provided on the top side of the carrier. Two contact rails 15a and 15b, made of a highly conductive material and spaced parallel to each other, are arranged on the top side 13. These contact rails merge with contact areas 16a and 16b on the left side. The contact rails 15a and 15b contact a wide, sheet-like heating conductor 18 between them. In this respect, see, for example, EP 3250003A1. Here, the direction of the current through the heating conductor 18 is perpendicular to the longitudinal direction of the contact rails 15a and 15b.

[0030] The voltage supply source 20 is connected to contact areas 16a and 16b via contact wires 17a and 17b. This is known in the prior art. Advantageously, the voltage supply source is a 230V household AC power supply voltage. It can also be used in the automotive field or in automobiles, that is, 12V or 48V or even higher DC voltages.

[0031] Electrode 22 extends in a zigzag manner along six parallel tracks within the region of heating conductor 18. These tracks can be spaced approximately the same distance from each other, but they can also be spaced at varying distances, for example, for different power densities or to allow for more precise evaluation of the defined area. The top and bottom tracks can also extend closer to contact tracks 15a and 15b. Electrode 22 has two electrode connectors 23a and 23b on its left side. Resistance measuring device 25 is connected via electrode lines 24a and 24b. Therefore, the resistance of electrode 22 can be measured, and the temperature can be determined based on the temperature dependence of said resistance. For this purpose, electrode 22 is constructed from the material mentioned at the beginning, having a silver content of 10% to 90% or 80% to 90%. However, the material mentioned at the beginning can also be used for the electrode.

[0032] As can be seen, due to the temperature-dependent variable resistance of electrode 22, temperature measurement does not allow for localized temperature measurement at a single point, but rather allows for temperature measurement distributed or averaged over the area covered by electrode 22. As is known from the prior art mentioned at the beginning, leakage current detection is used for localized temperature measurement, particularly for detecting hazardous localized overheating. The leakage current detection device is then connected by means of contact lines 17a and 17b and electrode lines 24a and 24b.

[0033] For the purposes of explanation, please refer to the following: Figure 2 And mainly referencing the aforementioned existing technologies. Figure 2 The carrier 12 has a carrier top side 13 with a layered structure and a carrier bottom side 14. Here, the carrier bottom side 14 is in contact with water W intended to be heated by the heating device 11. The layered structure on the carrier top side 13, manufactured by means of thick film technology, has the functional insulator 27 of the carrier 12 as the bottom layer. The electrode 22 is applied to the functional insulator 27 in a desired form. Variations of this form have already been explained at the beginning and will be referred to below. Figures 4 to 5 Further description. Electrode 22 has an electrode connector 23 on the right side, to which electrode wire 24 is connected, for example, by welding. The electrode wire can also be welded; alternatively, a contact connection by means of a press contact or a clamping plug is possible.

[0034] Electrode 22 is covered by an insulating layer 29 having the dielectric properties mentioned at the beginning. These include a sharp drop in resistance and the ability to flow leakage current at certain relatively high temperatures, such as 350°C to 400°C. Here, this leakage current can flow from a heating conductor 18 applied to the insulating layer 29 to the electrode 22. The heating conductor 18 has a contact area 16 applied thereto on its right side, which can be connected by means of a contact wire 17. At this temperature, there is a risk of permanent damage if this continues for a period exceeding 1 minute or 20 seconds.

[0035] A cover layer 31 is then applied to the heating conductor 18. The cover layer leaves a contact area 16 for subsequent attachment of the contact wire 17, similar to how the electrode connector 23 remains free when the insulating layer 29 is applied. The cover layer 31 serves to provide external protection for the structure of the carrier device 11, particularly to protect the heating conductor 18 from the surrounding atmosphere and especially from oxidation.

[0036] The functional principle of leakage current measurement and the temperature at which leakage current measurement can be performed will not be discussed further here, as these can be readily obtained from existing technology. (Reference) Figure 1 This means that leakage current flows from the heating conductor 18 to the electrode 22 at specific hot spots in the insulation layer 29 between the heating conductor 18 and the electrode 22. There is no leakage current or no noticeable leakage current flow in the range well below the critical temperature.

[0037] Temperature measurement of the heating device 11 via the temperature-dependent resistance of electrode 22 can be performed at any time. This can also be advantageously performed simultaneously with leakage current monitoring.

[0038] Figure 3 An alternative structure is shown. The heating device 111 with a carrier 112 has three parallel contact rails 115a, 115ab, and 115b on the top side of the carrier. The contact rails have corresponding contact areas 116a, 116ab, and 116b on the left side. This is still similar to... Figure 1 In this case, the heating conductor 118 can cover a continuous area, that is, from the upper contact rail 115a down to the lower contact rail 115b. The intermediate contact rail 115ab extends in the middle and forms an intermediate tap. Depending on the supply voltage applied to the contact areas 116a, 116ab and 116b, the two heating conductors 118a and 118b can be connected in series or in parallel as local heating conductors, or they can be connected in series or in parallel under different supply voltages.

[0039] The upper electrode 122a extends in a single loop between contact rails 115a and 115ab above the upper local heating conductor 118a. The upper electrode can be electrically contacted on the left side via two electrode connectors 123a, and, for example, according to... Figure 1 A resistance measuring device, not shown here, can be connected. Similarly, a leakage current detection device can be connected in the manner described above. A lower electrode 122b of the same design extends above the lower local heating conductor 118b between contact rails 115ab and 115b. The lower electrode can be electrically contacted in this manner via an electrode connector 123b provided on the left side. Therefore, leakage current can be detected not only through the two local heating conductors 118a and 118b, but also the corresponding absolute temperature.

[0040] Figure 4 An alternative structure of the heating device 211 according to the invention is shown. Four parallel strip-shaped local heating conductors 218a, 218b, 218c, and 218d are provided. They are connected in series with each other by means of contact rails 215 and have two contact areas 216a and 216b. Two electrodes are provided in sequence, specifically an upper electrode 222a and a lower electrode 222b. The upper electrode 222a extends virtually in a loop, practically entirely centrally, along the two local heating conductors 218a and 218b. The upper electrode can be electrically contacted at its ends via electrode connectors 223a. Similarly, the lower electrode 222b extends virtually along the entire length of the two lower local heating conductors 218c and 218d. The lower electrode is electrically contacted by means of electrode connectors 223b at its ends. Therefore, since only two electrodes 222a and 222b are present, which are separate from each other, leakage current detection can be performed in both areas. Similarly, even though the four local heating conductors are always connected in series in the same way, temperature measurements can be taken in the upper and lower halves, respectively, by the temperature-dependent resistances of electrodes 222a and 222b.

[0041] Figure 5 An alternative configuration of the heating device 311 is shown. On the carrier 312 having a carrier top side 313, relative to... Figure 4 In a simplified manner, two spaced-apart and parallel local heating conductors 318a and 318b are arranged. These local heating conductors are connected on the right side by means of a contact rail 315. On the left-hand side, the local heating conductors can be electrically connected in the manner described above by means of short contact rails 315 and contact areas 316a and 316b. The distance between the local heating conductors is relatively large, but it can also be smaller, particularly even only two to four times the width of a single local heating conductor.

[0042] Similar to Figure 4In this case, the outer electrode 322a extends over the entire length of both the upper local heating conductor 318a and the lower local heating conductor 318b. In doing so, it also extends below the right-hand side contact rail 315; however, leakage current is not desired there. Nevertheless, temperature measurement can still be performed here. The outer electrode 322a can be electrically contacted via the contact area 323a.

[0043] An inner electrode 322b, having two electrode connectors 323b, extends in a loop within the free region between the two local heating conductors 318a and 318b. The inner electrode can also be used for leakage current measurement, where, given the large distance from the local heating conductors 318a and 318b, leakage current can hardly be assumed to occur on the inner electrode 322b. For this purpose, an outer electrode 322a is provided last. The inner electrode 323b can be provided solely for temperature measurement. The inner electrode can advantageously be applied in the same manufacturing steps as the outer electrode 322a, so that a temperature measuring device or a temperature sensor can thus be manufactured in the same steps, wherein the outer electrode 322a required for leakage current detection is also applied. Figure 2 As can be seen, all layers are advantageously applied via a thick-film process, particularly by means of screen printing. Therefore, the method has very low complexity and incurs costs primarily due to the additional electrode material. Furthermore, the internal electrode 322b allows for temperature measurement at a distance from the local heating conductors 318a and 318b, which is considered advantageous. Thus, the temperature caused by the inherently relatively high temperature of the heating conductors (e.g., by a process similar to...) Figure 2 The deterioration of the temperature of the water heated by the heating device 311 is reduced or even prevented.

[0044] Figure 6 A heating device 11 with a carrier 12 is shown in a simplified manner, in which a heating conductor 18 with a large surface area extends between two contact rails 15, similar to... Figure 1 Various possible designs of electrodes 22A to 22E are applied in the area between contact rails 15. The electrodes are shown only in reduced size and as examples for the basic illustration. Each electrode has two electrode connectors 23. At least two electrode connectors may also be present, in the sense that additional center overlaps may still be present.

[0045] Electrode 22A has a sheet-like design. Although the electrode is shown here as having only a small surface area, specifically covering an area smaller than that of the heating conductor 18 between the two contact rails 15, it can actually have a fairly large surface area. In particular, the electrode can actually occupy the entire area of ​​the heating conductor 18 between the two contact rails 15. Thus, electrode 22A is an example of a sheet-like design or a large surface area design.

[0046] With Figure 1 Electrode 22B is designed in a similar manner. The electrode is relatively narrow, tortuous, and long. Electrode 22C has a sheet-like design similar to electrode 22A but is slightly larger.

[0047] Electrode 22D has an elongated design, but is significantly wider than electrode 22B and the narrow electrode 22E above it. The electrode is intended to demonstrate that an elongated electrode designed as an electrode rail can also have a certain width. The width can be provided such that the electrode covers a specific area, or that it has a certain amount of resistive material, that is, given a defined or predetermined thickness, it has a specific resistance. Therefore, given a predetermined resistive material, the width of the electrode can be used as a parameter to achieve a specific resistance.

Claims

1. A heating device, comprising a temperature measuring device for the heating device, wherein the heating device has: -Sheet-like carrier, - At least one heating conductor on the sheet-like carrier - Slender electrodes on the sheet-like carrier - A layered structure on the carrier, the layered structure having an insulating layer between the heating conductor and the electrode. - A measuring device for detecting localized high temperatures at the heating device, wherein the measuring device is connected to the electrode and the heating conductor, and is designed to detect temperature-dependent leakage current through the insulation layer between the heating conductor and the electrode, and to evaluate it as a measure of localized temperature changes at the heating device. in: The electrode is made of a material whose resistance is temperature-dependent, wherein the temperature dependence is between 0.0005 ppm / K and 0.01 ppm / K or between 500 ppm / K and 10,000 ppm / K in a temperature range between 0°C and 500°C. The temperature measuring device is connected to the electrode to measure the temperature at the electrode using the temperature dependence of the electrode's resistance. The electrode has two electrode connectors and is connected to the temperature measuring device through the electrode connectors.

2. The heating device according to claim 1, wherein, Within a temperature range between 0°C and 500°C, the temperature dependence of the electrode's resistance lies between 0.0015 / °C and 0.005 / °C, or between 1,500 ppm / K and 5,000 ppm / K.

3. The heating device according to claim 1, wherein the electrode is at least partially covered by the heating conductor, and wherein the insulating layer is located between the electrode and the heating conductor.

4. The heating device according to claim 3, wherein, The section of the electrode covered by the heating conductor extends along the longitudinal direction of the heating conductor.

5. The heating device according to claim 4, wherein, The section of the electrode covered by the heating conductor extends along at least 70% or 90% of the longitudinal extent of the heating conductor.

6. The heating device according to claim 1, wherein, The electrode has a width that is smaller than its length, wherein the length is at least 20 times the size of the width.

7. The heating device according to claim 1, wherein, The insulating layer has a resistance of at least 1 MΩ in the temperature range between 0°C and 150°C between the top and bottom sides or between the heating conductor and the electrode.

8. The heating device according to claim 1, wherein, The electrode has a total resistance between 50Ω and 100kΩ in a temperature range between 0°C and 500°C.

9. The heating device according to claim 1, wherein the electrode has a constant width along its longitudinal direction.

10. The heating device according to claim 1, wherein the electrode has a constant thickness along its longitudinal direction.

11. The heating device according to claim 1, wherein the electrode has a silver content of up to 95% as the electrode material.

12. The heating device according to claim 1, wherein the electrode material has a variable temperature coefficient of resistance.

13. The heating device according to claim 1, wherein, The heating conductor has a plurality of interconnected local heating conductors, wherein each of the local heating conductors covers an electrode or electrode segment.

14. The heating device according to claim 13, wherein, A connection section is provided between the individual local heating conductors, consisting of a conductor material having a specific resistance of at most 1 / 10 of the resistance of the heating conductor.

15. The heating device according to claim 1, wherein, At least one additional electrode is provided, which is made of the same material as the electrode and is not covered or overlapped by the heating conductor, wherein the lateral distance between the additional electrode and the heating conductor is at least 1 mm or at least 2 mm, or twice the width of the electrode rail.

16. The heating device according to claim 15, wherein the additional electrode is further connected to the temperature measuring device.

17. The heating device according to claim 1, wherein, A carrier insulating layer is applied to the carrier, at least one of the electrodes is applied to the carrier insulating layer, the insulating layer is applied to the electrode, the heating conductor is applied to the insulating layer, and a cover layer is applied to the heating conductor.

18. The heating device according to claim 1, wherein, An insulating layer is applied to the carrier, a heating conductor is applied to the insulating layer, an insulating layer or a dielectric layer is applied to the heating conductor, an electrode is applied to the insulating layer or the dielectric layer, and a capping layer is applied to the electrode.

19. A method for measuring temperature at a heating device according to claim 1, wherein, Temperature is first detected by means of a temperature-dependent leakage current flowing through the insulation layer between the heating device and the electrode, and then the temperature is measured at the heating device by measuring only the temperature change at the electrode.

20. The method of claim 19, wherein the temperature change at the electrode is evaluated as a change in temperature over time.

21. A method for manufacturing the heating device according to claim 1, wherein, The heating device has multiple heating conductors, wherein all of the heating conductors of the heating device, as well as possibly some local heating conductors, are applied in the same method step and are applied by the same heating conductor material.

22. The method according to claim 21, wherein, The heating conductor has a plurality of interconnected local heating conductors, each of which covers an electrode or electrode segment, wherein all the heating conductors of the heating device, as well as possibly the local heating conductors, are applied in the same method step and are applied by the same heating conductor material.

23. A method for manufacturing the heating device according to claim 1, wherein, The heating device has multiple electrodes, wherein all of the electrodes of the heating device are applied in the same method step and are applied by the same electrode material.

24. The method of claim 23, wherein the heating device has at least one additional electrode made of the same material as the electrode and not covered or overlapped by the heating conductor, wherein the lateral distance between the additional electrode and the heating conductor is at least 1 mm or at least 2 mm or twice the width of the electrode rail.

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