WO2019092016A1

WO2019092016A1 - Electric vehicle-heating device

Info

Publication number: WO2019092016A1
Application number: PCT/EP2018/080467
Authority: WO
Inventors: Martin Brüll; Egor SAWAZKI; Markus Wolf; Erich Mattmann
Original assignee: Continental Automotive Gmbh
Priority date: 2017-11-09
Filing date: 2018-11-07
Publication date: 2019-05-16
Also published as: DE102017219960A1

Abstract

An electric vehicle-heating device (H) has a plurality of conductor sections (L) that run along one another. The heating device further comprises a plurality of connecting sections (V) that connect the conductor sections (L) in series. The conductivity along the connecting sections (V) is at least double the conductivity along the conductor sections (L).

Description

description

Electric vehicle heater It is known to use electrical resistors in special vehicles for generating heat. In order to generate the heat, conductor tracks are used, which occupy the area in the form of meander structures. This results in a large overall length of the conductor, so that even with materials that have a relatively high specific conductance, such as metallic materials, a sufficient total resistance (adapted to nominal voltages of 12, 48, 400 volts or 800 volts or more) can be achieved. It is known that to realize an electrical

Heating device, an electrically insulating support is used, on which the Heizwiderstandsmaterial is applied along a continuous line, so that there is a continuous, usually loop-shaped conductor, which consists of Heizwiderstandsmaterial and is applied to the support. It has been recognized by the inventors that with such structures limits arise in the maximum heat output based on the total area. It is therefore an object of the invention to indicate a possibility with which a vehicle heating device with increased area-related heat output can be realized.

This object is achieved by the electric vehicle heating device according to claim 1. Further features, embodiments, feature combinations, features and advantages will become apparent from the description and the figures.

On closer examination of the usually selected Schlamp- form of Heizleiterbahnen of the prior art was recognized by the inventors, that significantly higher temperatures occur at the curved pieces, which connect side by side extending sections to each other parallel, straight sections. This is due to the fact that heat is generated at the ends of the juxtaposed sections from these sections as well as from the section connecting them, whereby only in the middle of adjacent sections only this heat is generated and not additionally generated by a section which connects the sections running side by side.

However, the rated or peak power of a heater resistor is limited by the maximum temperature that can occur on the track without permanent damage. Thus, if in some, few areas significantly higher temperatures occur than in other areas, these areas, which have the elevated temperatures, the limiting factor in the design of electric heating elements.

In particular, there are limits in maximizing the area-related heat yield.

It has been recognized that at connecting portions, the conductor portions (i.e., in particular, side by side

Connect sections) in series, no limiting, particularly high temperatures occur when these connecting sections have a higher conductivity coating than the conductor sections. As a result of the higher conductivity coating, less heat is generated at the connecting sections, so that even in the case of dense arrangement of the conductor track sections (and in particular their ends) no so-called hotspot is produced, which could represent a limiting factor overall. It is beaten before ^¬ thus an electric vehicle heating device, comprising a plurality of conductor portions. These run along each other, in particular parallel or along a common course. The conductor sections (in particular two adjacent ones thereof) extend side by side. The conductor sections preferably extend equidistant from one another; in a straight course this corresponds to a parallel arrangement with each other. The heating device further comprises a plurality of Verbindungsab ^¬ sections that connect the conductor sections (electrically) in series with each other. In particular, the connection sections each connect two adjacent conductor sections in such a way that the conductor sections are electrically connected in series. The connecting portions each connect two ends of conductor portions.

In order to avoid temperatures occurring at the connecting sections and the connected ends of the conductor sections, which are increased in relation to the average temperature of the conductor sections, the connecting sections are provided with a conductivity covering which is at least twice (or at least the three-, four- is five, ten or twenty times the conductivity of the conductor sections). Other embodiments provide that the

Conductivity of the connecting portions is at least 30, 40 or 50 times the conductivity of the conductor ^¬ sections.

As a result (compared with the average) increased Tem ^¬ peraturentwicklung is reduced at the connecting portions, so that despite the increased conductor density (Verbindungsab ^¬ sections including the connected ends of the conductor portions) does not result in increased temperature at the connecting portions.

In particular, the connecting portions are formed so that they do not give off more than half the heat in length relative to the conductor portions (corresponding to a heat release coating which is not more than half, as shown). The conductivity of the Verbindungsab ^¬ sections may be as mentioned at least twice, three times, five times or ten times the conductivity of the conductor sections. The conductivity coating is the conductivity along the relevant section (ie along the longitudinal extent or along the course of the sections) with respect to the length. The conductor sections can also be referred to as longitudinal sections or as Heat generation sections (as they contribute significantly to the heat generation in contrast to the Ver ^¬ binding sections).

The conductivity coating is the reciprocal of the resistance coating. The higher the conductivity coating is, the lower is the heat related to the length of the relevant section. Characterized in that the connecting sections have a higher capacity Leit ^¬ covering as head portions Wär ^¬ sea generation compared to the conductor sections (as well based on the length) is reduced. No hotspots are formed at the connection ^sections , which represent the limiting factor of the total heating power of the heating device.

The higher conductivity coating of the connecting sections with respect to the conductor sections can be achieved by various measures, in particular by selecting the specific conductivity, the cross-sectional area, the thickness or the width of the relevant connecting sections. The different sizes for the mentioned sections, such as specific conductivity, cross-sectional area, thickness or width, produce a higher area-related heat output at the line sections than at the connecting sections.

The specific conductivity, the cross-sectional area, the thickness and / or the width of the connecting sections is at least twice the specific conductivity, the cross- ^{sectional area} , the thickness or the width of the conductor sections. Here, the specific conductivity of the connection portions ^¬ twice, three times, five times or ten times the specific conductivity of the conductor portions may be. Further embodiments provide that the specific conductivity (of the material) of the connecting ^{sections is} at least 30, 40 or 50 times the specific conductivity (of the material) of the conductor sections.

This is achieved, for example, by a suitable choice of material. For example, the material of the connecting sections may be aluminum or an aluminum alloy, or else copper, in particular a material whose specific conductivity is at least 30, 50 or 70% of the specific conductivity of aluminum. The material of the conductor sections may be about a NiCr alloy, such as a NiCr compound having a resistivity of at least 20 or 30 times the resistivity of the material of the Verbindungsab ^¬ cuts.

Alternatively or in combination with the increased specific conductivity of the cross-sectional area, the at least twice, at least three-fold, at least five times or at least ten times the cross-sectional area of the Leiterab ^¬ sections, respectively. Is the cross-sectional area of the Verbin ^¬ dung portions and the conductor portions constant, this applies to the constant cross-sectional areas. Is the cross-sectional area of the connecting portions along the

The longitudinal course is variable and / or the cross-sectional area of the conductor sections varies along the course, this applies to the integral of the cross-sectional areas over the conductor sections relative to their length or to the reciprocal of the integral of the reciprocals of the cross-sectional areas along the length of the sections in question the total length of the sections concerned. Furthermore, the thickness and / or the width of the connecting sections may be at least twice, three times, five times or ten times the thickness and / or width of the conductor sections. In addition to the specific conductivity, the cross-sectional area, the thickness or the width, it is also possible to use other features which have an effect on the conductivity coating, wherein these are configured in such a way that the conductivity coating of the compound ^{sections is} at least twice, three times, fivefold or so Ten times the conductivity of the conductor sections be ^¬ runs. As mentioned, in particular, the specific conductivity can be used to achieve a higher conductivity of the connection sections compared to the conductor sections. The connection sections can also be off be provided a different material than the conductor sections. The specific conductivity of the material of the connection ^¬ portions is at least twice, three times, four times ^¬, five times or ten times the specific conductivity of the material of the conductor sections.

In particular, as mentioned, the material of the connection ^¬ sections aluminum be, while the material of the conductor ^¬ portions having a poor conductive material, game as examples a Heizwiderstandmaterial as a heat conductor ^¬ alloy, a nickel-copper alloy, a nickel-chromium alloy or a material that sold under the name "Kanthai", which is in particular an alloy of iron, chromium and aluminum or a copper-nickel alloy.

In particular, a nickel-chromium compound having a chromium content of 10 - 30%, 17 - 23% or substantially 20% can be used, which in particular has a nickel content of 90% - 70% or substantially 80%.

The electric vehicle heating apparatus described herein has connecting portions having a heat generation amount ("heat generation deposit") lower than that of the conductor portions, and more preferably less than 50%, 20% or 10% of the heat generating deposit of the conductor portions. At the connecting sections, that is, where two conductors in the form of a (narrow) curve ^{abut on} one another, namely the connecting section and the two ends of the conductor sections to be connected, is thus not more than 200%, 150%, 120% or 100% or not more than 80%, 70% of the heat generated compared to conductor sections, which are located between the ends to be joined of these conductor sections.

The electric vehicle heater described herein is an ohmic heater and electrically corresponds to a heating resistor. The connecting sections and the ladder ^

cuts preferably run along a surface. This surface corresponds in particular to a flat surface, resulting in the flat surface good heat radiation. However, the surface can also be curved outward. In other words, the surface may have a convex curvature in at least one direction.

The conductor sections and the connecting sections are arranged on an electrically insulating carrier, for example made of a heat-resistant material, for example in the form of a ceramic carrier. The carrier can be arranged on a body (and in particular is heat-transferring connected to it in a planar manner), for example a heat sink. The carrier may be a cold gas sprayed layer disposed on a body (such as an aluminum material), for example. The connecting portions and the conductor portions are fastened on the carrier, wherein ^¬ example by gluing or by a corresponding (connecting) plot of the sections. The Verbindungsab ^¬ sections may be designed as a so-called bus bars, ie as busbars. The carrier may form a DCB substrate together with the connecting portions (DCB stands for direct copper bonded, ie, a substrate in which copper conductors are directly mounted on a carrier such as a ceramic substrate). In addition, the connecting sections may be arranged overlapping on the conductor sections, so as to achieve a flat connection (not only in cross-section or on end faces). For example, the connecting portion ends of the conductor sections to be connected can cover over the entire width of the conductor sections, so as to establish an electromechanical contact by means of the superimposed surfaces of the sections. The heater may have at least two terminals provided at two ends of the series circuit provided by the conductor portions and the connecting portions (connecting them serially). The connections may be formed like the connection sections and have a connection structure, for example in the form of a surface, a screw connection or a pin structure. It can Furthermore, at least one further connection between the ends of this series connection may be provided, for example in the form of a tap on a connection section or also on a conductor section.

The conductor portions (together with the Verbin ^¬ dung portions in particular) are distributed over an area. The conductor sections run along a surface next to each other and are preferably uniformly distributed. The conductor sections run parallel to one another and in this case can be straight in particular. However, it is also possible curved courses of conductor sections, in particular in the form of a screw or generally in the form of curved conductor sections. The conductor sections are arranged equidistant from one another, wherein in particular adjacent conductor sections extend equidistantly along a curve. This applies in particular to subgroups of the conductor sections. Due to the parallel or equidistant course of the conductor sections results in a relatively homogeneous heat generation over the area. Together with the inventive design of the connecting portions, through which an increased heat generation is reduced at the connecting portions, results in a total homogeneous, area-related heat output. In particular, the heat emission or the conductor sections Wär ^¬ mewandlungsbelag at least two, three, four, five, ten or Zwanzigfache-, the heat emission or heat ^¬ conversion coating of the connecting portions is.

The ends of adjacent conductor sections are preferably minimally spaced apart, for example in the form of conductor sections which terminate at the same height. In other words, ends of adjacent conductor sections, which are each connected to one another by means of a connecting section, are spaced from each other by a distance which is not more than 120%, 150% or 200% of the distance of the conductor sections. Thus, although the ends of the adjacent conductor sections (which are connected to one another by a connecting section) may not end exactly at the same height, however, the height offset from one another is preferably smaller than the distance of the conductor track. sections, in particular the center lines of the adjacent conductor sections.

The inventive design of the connecting sections with respect to the conductor sections with respect to the conductivity causes the conductor sections can be arranged particularly closely aufei ^¬ nanderfolgend without this would result in the connection sections and the relevant ends of the conductor sections compared to the rest increased temperature generation , The heating device according to the invention is therefore designed such that the distance between the Leiterab ^¬ sections (in particular the adjacent conductor sections) to each other is not more than 10%, 25%, 50% or 75% of the width of the respective conductor sections. In particular, the distance between the conductor sections is not greater than the width of the conductor sections. It is a particularly dense design he ^¬ allows and in particular results in a particularly high area-related heat yield (ie heat conversion performance). As mentioned, in the prior art, a particularly narrow embodiment of the conductor sections is associated with a very narrow guidance of the connection sections, hotspots resulting from this narrow guide at the connection sections which limit the overall performance of the heating device. With the heating device according to the invention, a particularly dense arrangement of the conductor sections can be realized. The conductor portions and the connecting portions are preferential ^¬ arranged surface, wherein a closed line which circumscribes all the conductor portions and connecting portions having a surface area (of at least 50%, 75%, 80% or 90% of the conductor sections in particular the conductor portions and the connecting sections). This allows a particularly compact design at high

Rated capacity. The line circumscribing the conductor portions and the connecting portions of the heating device, wherein ^¬ game as a rectangle or a square, in particular when the conductor sections are mutually parallel and terminate at the same height. Alternatively, the closed line can also be used be a polyhedron, such as a trapezoid, a parallelogram, generally a square, a hexagon, octagon or a circle or an oval. The shape that covers the sections (and thus the shape of the heat-emitting surface) may be adapted to the application, as mentioned, the majority of the area covered by the sections (defined in particular by the circumscribed, closed line) of the conductor sections or is covered or occupied by the conductor sections and the connecting sections.

Less than half the area on which the sections (i.e., the conductor and connecting sections) are located (including the gaps between the sections) is not covered by a section. In other words, preferably less than half of the surface area is the closed one

Line, which circumscribes the sections, free or not covered by a section, in particular ladder section.

The vehicle heating device is designed in particular as a heating resistor, for example an air conditioner of a

Vehicle or as Rekuperationswiderstand a vehicle or as a load resistance of a vehicle or for general applications. In this case, the vehicle is in particular a hybrid vehicle or an electric vehicle in which heat is generated by means of a heating resistor. The heating device may in particular also as a heating resistor of an exhaust aftertreatment ^¬ averaging device, such as a catalyst, may be formed. The exhaust aftertreatment device or the catalyst preferably belong to a vehicle. The Rekuperationswiderstand is a resistor that receives power in a vehicle electrical system when electrical energy is recuperated, that is generated by an electric machine kinetic energy in the form of electrical energy. The Rekuperationswiderstand thus forms a load for a working as a generator electric machine, which is for example in an active state when heat is to be generated or when an accumulator, for example, a Aktionsakkumulator, about due to the state of charge is unable to absorb all the recuperated energy.

The vehicle heater described here has in particular a nominal power of at least 500 watts, at least 1 kW, at least 2 kW, at least 5 kW or at least 10 kW, the rated power may also be 20 kW or more.

The vehicle heater is preferably designed for a rated voltage of about 12, 48, 400 volts or 800 volts or more.

The sections mentioned here are longitudinal sections, in particular of conductor tracks.

The conductor sections, the connecting sections or both types of sections may be provided by a (structured) cold gas-sprayed layer. Furthermore, the longitudinal sections, the connecting sections or both types of sections can be realized by means of strips of material which are partially or completely embedded in the carrier. The conductor sections and / or the connecting portions may be trimmed by laser, such as by a constant resistance per unit length to have, as a amount of deviation of not more than 20%, 10 or 2% (over the length of the ex ^¬ section). The longitudinal sections can be designed as a cold gas sprayed conductor, in particular as a stainless ^¬ layer. The connecting sections are in particular made of an aluminum material. The connecting portions may be formed as a cold gas-sprayed layer. Preferably, the ends of the conductor portions are applied to (parts of the) connection ^¬ sections. The conductor sections may be applied as a cold gas sprayed layer (such as chrome nickel material) on a support (such as ceramic) which is ready provided with a cold gas injection layer (such as aluminum) forming the connecting sections. The driving ^¬ generating heater can be prepared by first forming the connecting portions are applied to a carrier, such as by cold gas spraying. Then, the conductor sections may be applied, such as by cold gas spraying, in particular a chromium nickel alloy or another Heizwiderstandmaterials (such as is mentioned herein).

The Heizwiderstandmaterial, for example, a specific resistance of approximately 2-10 ^¬ fish, 3 - having 6 or about 4 ohm mm ² / m. Ends of the conductor portions may overlap the connection portions or ends thereof. The portions may be tapped, such as by attaching taps, such as in the form of preferably cold gas-sprayed taps.

Furthermore, the heating device may comprise a body on which the carrier is arranged. The body is in particular made of a thermally conductive material, for example of a metal such as aluminum or copper or of an alloy, such as at least one of these metals. In addition, the conductor sections, the connection sections or both types of sections can each be provided by a continuous cold gas-sprayed layer, which is structured approximately by laser trimming. In particular, first of all the connecting sections can be applied as at least one continuous layer (for example at least one aluminum layer) (for example by cold gas spraying or another thermal spraying method), which is structured after application in the connecting sections, for example by laser trimming. The at least one continuous layer can be provided by two continuous, opposing strips, in particular on opposite edges of the carrier. By structuring or laser trimming the strips are interrupted several times in their longitudinal direction; it will become apparent from each other (electric) separate strip portions forming the Verbin ^¬ dung portions. The conductor portions (in particular ^¬ sondere after application of the connecting sections) is applied as a patterned portions, such as a strip (For example, by cold gas spraying or other thermal spraying method), or are applied as (at least) a continuous layer, which is patterned after application, such as by laser welding. By applying the material or the layer of the conductor sections, these are connected electromechanically to the connection sections. The structured sections or the at least one continuous layer, forming the conductor portions are applied so that they ver ^¬ bind the plurality of continuous layers forming the connection portions. By structuring the conductor portions and / or the connection portions, the conductor portions are connected in series, and are connected by the connection portions, respectively.

In particular, taps of the connecting portions can be formed by the connecting portions are struc ^¬ riert applied by or be structured after applying the layer or layers that constitute the connecting portions, such as by laser trimming. The conductor sections can also be applied before the application of the connecting sections and preferably also structured.

In other words, the vehicle heater may be provided with a plurality of conductor sections that are cold sprayed and laser trimmed or patterned by laser trimming (or realized as a structured deposited layer). The vehicle heating device can be provided with connecting sections which are cold-gas-injected and laser-trimmed or structured by laser trimming (or realized as a structured layer). Ends of Leiterab ^¬ sections are arranged on parts of the connecting portions, or vice versa. The connecting sections and the Leiterab ^¬ sections are arranged on the carrier. The carrier may be arranged on a body as described above. This arrangement can be provided by cold gas spraying or by another thermal spraying method. The carrier may be formed as a cold gas-sprayed layer. A description is given of a vehicle electrical heater having a plurality of conductor sections, which may be formed as shown here and in particular run along one another. The device further comprises a plurality of connecting sections, which are designed in particular as shown here. The connecting sections preferably connect the conductor sections in series. The connecting sections and / or the conductor sections are cold gas-sprayed layers. In particular, the conductor portions partially overlap the connection portions to be electrically connected thereto by physical contact. The conductor sections are partially sprayed onto the connecting sections. The conductivity of the connecting portions may be at least twice the conductivity of the conductor sections, or behave in another way, shown here, the conductivity of the conductor sections. Instead of the cold spraying described here, another thermal spray ^{information model} can be applied; the sections may be generally sprayed layers, in particular thermally sprayed layers. The sections form a sheet resistance.

The conductance of the connecting sections is designed (based on the conductance of the conductor sections) such that in continuous operation, for example at rated power, a temperature difference between the maximum temperature of all conductors and sections and the average temperature of all sections of not more than 10K, 20K, 30K or 50K occurs. In other words, the conductance of the connecting portions (relative to the conductance of the conductor portions) is designed to provide a power (ie electric power to heat conversion based on the length of the portion) for the connecting portions whose maximum is not more than 200%, 150%, 120% or 100% of the (average of) power ^¬ covering the conductor sections amounts.

The connecting sections and / or the conductor sections are formed as strips. The conductor sections run along one another, in particular parallel to one another, and preferably equidistant. The connecting ^portions may be formed of wire from ^¬ , wherein the resulting wire sections not only a rectangular cross sections but also others

May have cross-sectional shapes. The conductor sections can be made of wire.

The heating device can thus comprise surface-sprayed resistors which are cold-sprayed on a body, in particular a body, in an insulating manner. In order to show a good heat conduction (to the body), a ceramic material with a good heat conduction (eg with a thermal conductivity of at least 20 W / (m * K), 50 W / (m * K), 100 W / (m * K ), 150 W / (m * K) or 200 W / (m * K), such as aluminum nitride, alumina, or other ceramic material) are applied to a heat sink (such as in the form of the body) by thermal spraying. The heat sink may be made of aluminum or an aluminum alloy. The ceramic material is not only a heat conductor but at the same time an insulator. In a further (especially subsequent) step, a heating conductor material (in particular as stated here) is also applied by thermal spraying. As a result, the conductor sections are formed. This material preferably has a high strip resistance, ie a higher resistance layer than the connecting sections, in particular a higher specific resistance. The ratio of resistivities may be, for example, at least 15, 25 or 30. In one embodiment, chromium nickel (NiCr 2 O) with a resistivity of approximately 4 ohm * mm ² / m is used to represent the conductor sections. In order to obtain a defined resistance value, the Flächenge ^¬ ometrie can be selected such that an increase in resistance (the conductor portions) can be realized by means of laser trimming. Large resistive surfaces (NiCr20 material) can be produced by injection molding (to form the conductor sections), each of which overlaps connecting sections (made of aluminum, for example). A predetermined number of sections and optionally performed taps results in a predetermined number of resistors. In a further production step, the Resistors (ie, the conductor sections) between the connec ^¬ tion sections actively prepared by means of

Laser structuring resistor material is cut out and thus predetermined resistance paths and thus also predetermined resistance lengths are generated. However, this means that only preset resistance values are achieved. The connection sections may in particular be designed as strip conductors. In the following embodiment it is shown how now the same area can be used to change the resistance value. The layer forming the resistors or the Lei ^¬ subparagraphs, in particular a chromium-nickel layer, is a defining surface by means of thermal spraying on two previously produced opposing conductor tracks (which constitute the connecting portions, in particular aluminum) applied. The tracks are at opposite edges of the carrier. There are (in number and / or arrangement) predetermined taps for subgroups of the resistors, ie the conductor sections produced, preferably ^{¬ produced} in the same operation. By means of laser structuring any number of resistance paths (ie conductor sections) can now be generated. Thus, for example, a resistance (ie the resistance of one or more conductor sections) can be changed (increased or decreased) by a multiple of its original value. Any resistance values within a given area can be realized for a desired power range and a fixed area factor.

FIG. 1 shows an exemplary embodiment of the heating device described here.

FIG. 1 shows a heating device H with a carrier T, on which conductor sections L and connecting sections V are arranged. The conductor sections are arranged parallel to one another, in the illustrated example in the planar shape of a rectangle. The connecting sections connect alternately ends of the Conductor sections, so that a series circuit of Lei ^¬ terabschnitte results. In other words, the conductor sections are connected in series MITEI ^¬ Nander by the connecting portions V. The result is the already mentioned series connection.

The ends of the series circuit are provided with two terminals P to which a voltage can be applied so as to conduct electric power, in particular, through the conductor portions L, which is converted into heat. The illustrated

Conductor sections all have the same width, and this also applies to the connection sections V. The width of the conductor sections with each other or the connecting sections may be different; In particular, the width of the conductor sections may be different from the width of the connection sections or may be the same.

Shown, is also that in the example shown, the width B of the conductor sections is greater than the distance A between the (adjacent) conductor portions L. This allows are very powerful surface-related heat capacity, thereby it is ^¬ enables that the connecting portions V a have significantly larger conductivity coating than the conductor sections L, which forms no hotspot at the connecting sections. In other words, the connection portions V are formed such that the area-related (or length-related) heat output at the connection portions is smaller than at the conductor portions. It is avoided that more heat is generated at the connection sections V or the area-related more heat from the connected ends of the conductor sections than at the conductor sections L in order to prevent hotspots which limit the total output of the heater H (or to such hotspots compared to

Structures with connecting sections and conductor sections to reduce the same conductivity coating). A carrier T is formed as a ceramic substrate, wherein the portions are formed as conductor tracks or as conductor tracks on this substrate. The sections form a track which varies a conductivity pad with the curvature. The conductivity coating of a section and its curvature are linked by an increasing function; a high curvature also means a high conductivity coating. Regions of the device in which the managerial subparagraphs are formed, have a lower part at surface covering ^¬ than areas of the device, in which joint portions or joint portions and head ^¬ portions are formed. Connecting portions from ^¬ sections of the heating resistor having a stronger curvature in its longitudinal axis than other portions, referred to as head ^¬ sections. A portion having a first curvature has a higher (at least double, triple, five, ten or twenty times) conduction stress than a portion having a second curvature smaller than the first curvature.

The material of the connecting portions V may have a resistivity of about 8 * 10 ^{~ 8} ohm * m, such as aluminum. The material of the conductor portions L may have a specific Wi resistor of about 2 * 10 ^~ * having ⁶ Ohm m, such as a

Ni-Cr alloy.

Claims

claims

An electric vehicle heater (H) having a plurality of conductor portions (L) extending along each other and having a plurality of connecting portions (V) connecting the conductor portions (L) in series, wherein the Leitfä ^¬ ability surface of the connecting portions (V) at least the Double the conductivity of the conductor sections (L) is.

2. Electric vehicle heater (H) according to claim 1, wherein the specific conductivity, the cross section ^¬ area, the thickness or the width of the connecting portions (V) at least twice the specific conductivity, of the cross-sectional area, the thickness or the width (B ) of the conductor sections (L) is.

3. Electrical vehicle heating device (H) according to claim 1, wherein the connecting portions (V) of a different material than the conductor portions (L) and the specific conductivity of the material of the connec ^¬ tion sections (V) at least twice, four times or Ten times the specific conductivity of the material of the conductor sections (L) is.

An electric vehicle heater (H) according to any one of the preceding claims, wherein the connecting portions (V) and the conductor portions (L) extend along a surface or a plane.

5. An electric vehicle heating device (H) according to any one of the preceding claims, wherein the connecting portions (V) and the conductor portions (L) on an electrically insulating support (T) are arranged.

6. Electric vehicle heating device according to one of the preceding claims, wherein the conductor sections (L) are straight and parallel to each other or be adjacent conductor sections (L) extend equidistant along a curve.

7. An electric vehicle heating device (H) according to any one of the preceding claims, wherein ends of adjacent conductor sections (L), each connected by means of a connec ^¬ tion section (V), not more than 120%, 150% or 200% of the distance the conductor portions (L) are spaced from each other.

8. An electric vehicle heater (H) according to any one of the preceding claims, wherein the distance (A) of Lei ^¬ terabschnitte (L) to each other not more than 10%, 25%, 40% or 75% of the width (B) of the respective Conductor sections amounts.

9. The electric vehicle heating device (H) according to claim 1, wherein the conductor sections and the connection sections are arranged flat and a closed line circumscribing all conductor sections and connection sections has an area of at least 50%, 75% or 80% of the conductor sections (L) are occupied.

10. Electric vehicle heater (H) according to one of the preceding claims, wherein the driving ^¬ convincing heater (H) as a heating resistor

Air conditioning of a vehicle or as Rekuperationswi- resistance of a vehicle is formed.

11. Electric vehicle heater (H) according to any one of the preceding claims, wherein the driving ^¬ convection heater (H) is designed for a rated power of at least 500 W, 1 kW, 2 kW, 5 kW or 10 kW.

12. An electric vehicle heating device (H) according to any one of the preceding claims, wherein the connecting portions and / or the conductor sections are formed as a cold gas-sprayed layer.