EP3631312A1

EP3631312A1 - Air heating device

Info

Publication number: EP3631312A1
Application number: EP18727167.1A
Authority: EP
Inventors: Martin Zoske; Volodymyr Ilchenko; Uwe Strecker; Bengt Meier; Nikolaus Gerhardt; Michael Schwanecke
Original assignee: Webasto SE
Current assignee: Webasto SE
Priority date: 2017-05-24
Filing date: 2018-05-08
Publication date: 2020-04-08
Also published as: EP3631317A1; DE102017121062A1; WO2018215198A1; US20200173688A1; EP3631314A1; CN110678705A; EP3631318A1; JP2020521272A; US20200224926A1; US20200094654A1; EP3631316A1; CN110691949B; EP3630513A1; WO2018215551A1; EP3631320A1; EP3631319A1; WO2018215197A1; CN110678343A; CN110662926A; WO2018215623A1

Abstract

The invention relates to an electric air heating device, in particular for a motor vehicle, comprising a first heating element (9a) and at least one second heating element (9b), the heating elements (9a, 9b) respectively comprising a first conductive layer, in particular a first metal layer (10a, 10b), a second conductive layer, in particular a second metal layer (11a, 11b), and a polymer layer (12a, 12b), the polymer layer (12a, 12b) comprising a polymer component and a conductive carbon component. An intermediate space (16a) is formed between the heating elements (9a, 9b) through which air can flow for heating.

Description

air heater

description

The invention relates to an air heater, in particular for a motor vehicle.

Electric air heaters (especially those used in mobile applications) are usually based on ceramic heating elements with a comparatively strong temperature-dependent electrical resistance, through which a self-regulation of the heat release is possible. These resistors are typically PTC elements (PTC for Positive Temperature Coefficient). These are usually made with heat exchanger surfaces

Aluminum sheet connected and are also contacted electrically. A PTC element comprises a PTC resistor, ie a temperature-dependent resistor with a positive temperature coefficient, which at low

Temperatures conduct electricity better than at high temperatures.

Disadvantages of conventional air heaters with ceramic PTC elements include i.a. an elaborate production by a comparatively complicated heat exchanger production and the installation of the ceramic elements, a usually necessary sorting of the ceramic elements due to manufacturing tolerances, a comparatively unfavorable power density in a heating element heat exchanger composite by a local heat generation, a comparatively strong restriction a maximum heating power through a thickness of the PTC material (due to a limited heat dissipation from the ceramic) and a comparatively high risk of short circuit, in particular due to a small geometric distance of components with a high voltage potential.

It is an object of the invention to provide an air heater that allows effective heating of the air. In particular, a high power density should be made possible with a comparatively small installation space. This object is achieved in particular by an electric air heater according to claim 1.

In particular, the object is achieved by an electric air heater, in particular for a motor vehicle, comprising a first heating element and at least one second heating element, the heating elements each having a first conductive layer, in particular a first metal layer, a second conductive layer,

in particular a second metal layer and a polymer layer, wherein the polymer layer is a polymer component and a conductive

Includes carbon component, wherein between the heating elements, a gap is formed through which air can be flowed to its heating.

A central idea of the invention is to provide heating elements each having two conductive layers (metal layers) and a polymer layer between the conductive layers (metal layers) with a polymer component and a conductive carbon component, the heating elements between them (at least) a gap

Form (air flow channel), so that through this gap

(Air flow passage or portion of such air flow channel) air can flow to their heating.

According to the invention, a comparatively large contact area between the conductive layers (leads, preferably metal plates) and the polymer layer (heat conductor layer) can be achieved, which results in a comparatively high power density (in comparison to conventional concepts, such as

Heating tapes in which a contact is usually achieved via introduced into the Heizleiterschicht two Litzenkabel) allows. Overall, a high power density for an existing installation space by a comparatively high contact area between the conductive layers and the

Reached polymer layer. In this case, a comparable safety, as in conventional PTC heaters, by a self-regulating polymer layer

(Heating layer) can be achieved. Overall, a rugged design can be achieved that is comparatively easy to manufacture.

Furthermore, the conductive layers (in particular metal layers, preferably metal plates) at the same time as a heat exchanger surface for Heating the passing air can be used. Optionally, this surface can still by unevenness, in particular projections, such as ribs and / or fins on the conductive layer (metal layer, in particular

Metal plate) are enlarged. To protect against a mechanical

Damage, moisture and / or short circuits can be a painting and / or sealing of the individual heating element or at least of

(Exposed) areas of the heating layer (s) or the entire component may be possible. In summary, a high power density (in a given space) by a high contact surface between

Conducting elements (the conductive layer) and the polymer layer

(Heizleiterschicht) can be realized. Here, a comparable security, as in conventional PTC heaters with ceramic heating elements can also be achieved by a self-regulating heating layer. Here are the

Manufacturing costs through the possibility of using low-cost materials and the possibility of simple manufacturing processes,

comparatively low.

Heating elements with a partially similar layer structure are also in

WO 2014/188190 AI has been described, however, for a surface heater and not for an air heater in which the heating elements form between them one or more air channels (for heating the same). air heater

However, in particular because of the large number of air ducts provided there, they differ conceptually from surface heaters.

First and / or second heating element can (at least in

Substantially) along an air flow direction. At this

Alternatively, it is preferable to employ heating elements having a comparatively large width (e.g., a width of at least 0.1 times or at least 0.2 times a length). In particular, the width means an (average) extent of the respective heating element which is perpendicular to a maximum extent (length), in particular in projection onto a plane which is defined by a connecting surface between the first conductive layer and the polymer layer. Alternatively, the first and / or second heating elements may be at an angle to the

Air flow direction (for example, at an angle less than or equal to 90 ° and greater than 0 °, in particular greater than 10 °) erstecken. When extending at an angle (greater than 0 °) relative to the direction of air flow preferably comparatively narrow heating elements are used (ie heating elements whose width is comparatively small compared to their length, for example less than 0.2 times or less than 0.1 times).

The width of the respective heating element may extend in the flow direction. At least one of the heating elements (preferably several or all of the heating elements) is preferably shorter in the flow direction than in a direction perpendicular thereto, e.g. 50% shorter.

A floor plan of the respective heating element (preferably several or all heating elements) may be polygonal, in particular quadrangular, preferably rectangular or oval, in particular elliptical, preferably (circular) circular.

At least one intermediate space (possibly several or all intermediate spaces) can be limited by (exactly) two or more heating elements.

The polymer layer is preferably a conductive layer with PTC behavior. A cross section of the intermediate space (air channel) may be polygonal, in particular quadrangular, preferably rectangular or oval, in particular elliptical,

preferably (circular) to be round. A cross section within a gap (air passage) may vary or be constant (over its length). Also

Cross sections of various spaces or air channels (ie spaces or air channels that are not through the same pair or the same group of

Heating elements are formed) may differ or be the same. For example, cross-sections of the intermediate spaces or air ducts may be slit-shaped (in particular as rectangular slits). The respective polymer layer (at least one of the heating elements, preferably several or all of the heating elements) may be thicker (at least on average) than the first and / or second conductive layer (metal layer) (for example at least 1, 1 times, preferably at least 1.5 times). The first and / or second conductive layer (metal layer) may be thicker than the polymer layer be fat.

Optionally, the first conductive layer (metal layer) of at least one heating element (preferably several or all heating elements) may be thicker as the respective second conductive layer (metal layer) (or vice versa), for example, 1.0 times to 2.0 times as thick. A maximum extent of first and / or second conductive layer (metal layer) and / or polymer layer of at least one heating element, preferably several or all heating elements (preferably defined by the maximum-possible distance of a

Point pair on / in the respective layer) is preferably at least 5 times, more preferably at least 10 times as large as an (average) thickness of the respective layer. The respective first and / or second conductive layer (metal layer) of at least one heating element (preferably several or all heating elements) may be formed as a conductive plate (metal plate).

The respective first and / or second conductive layer of at least one heating element (preferably several or all heating elements) may be a continuous layer. Alternatively, the first and / or second conductive layer may be discontinuous, e.g. B. several

Have (sheet) bands for contacting the polymer layer. Another alternative for electrical contacting (in the form of the conductive layer) is the use of at least one wire or narrow strip or a wire mesh or the like as a conductive layer or component thereof.

The term "conductive" with regard to the conductive carbon component and the conductive layer is to be understood as an abbreviation for "electrically conductive".

An electrically insulating material is in particular a material to be understood that includes at (at room temperature of preferably 25 ° C), an electrical conductivity of less than 10 ^"1 S ¹ irr ¹ (possibly less than ^{10" 8} S ¹ irr ¹⁾ , Correspondingly, an electrical conductor or a material (or coating) with electrical conductivity is to be understood as meaning a material which has an electrical conductivity of preferably at least 10 s ¹ irr ¹ , more preferably at least 10 ³ s ¹ irr ¹ (at room temperature, in particular 25 ° C).

The (respective) first and / or second conductive layer (metal layer)

at least one heating element (preferably several or all heating elements) may have a thickness of at least 0.1 mm, preferably at least 0.5 mm, more preferably at least 1.0 mm and / or at most 5.0 mm, more preferably at most 3.0 mm. In particular, the respective thickness is an average thickness or a thickness of the largest area of the respective constant thickness layer.

The (respective) polymer layer of at least one heating element (preferably several or all heating elements) may have a thickness that is greater than the (average) thickness of the first and / or second conductive layer (metal layer), in particular by a factor of 1, 1 times , preferably 1.5 times as large.

A thickness of the respective polymer layer of at least one heating element

(Preferably, several or all heating elements) may be at least 1 mm, preferably at least 3 mm and / or at most 20 mm, preferably at most 10 mm.

The (respective) first and / or second conductive layer (metal layer) and / or polymer layer of at least one heating element (preferably several or all heating elements) may / may be (at least substantially) planar. If surveys (depressions) are provided, these may amount to less than 10% of an (average) thickness of the respective layer.

A sum of the cross sections of the spaces (or the one

Interspace) between the heating elements may be at least 2 times, preferably at least 4 times as large as a sum of the cross sections of the heating elements (in particular transversely viewed air flow direction or transverse to the width direction).

The (respective) first and / or second conductive layer (metal layer)

at least one heating element (preferably several or all heating elements) may be made of aluminum or an aluminum alloy.

The (respective) carbon component of at least one heating element

(Preferably, several or all heating elements) may be arranged so that it allows a flow of current, for. In particulate form (with the particles touching or being close together) and / or as

The carbon skeleton. Polymer component and carbon component of at least one heating element (preferably several or all heating elements) are preferably mixed or intertwined with each other. For example, the

Polymer component form a (skeletal) framework in which the

Carbon component is added or vice versa.

Preferably, the (respective) polymer layer comprises at least

5% by weight, preferably at least 10% by weight, more preferably at least 15% by weight, even more preferably at least 20% by weight and / or less than 50% of carbon (optionally without consideration of a carbon fraction of carbon) Polymer as such) or from the

Carbon component, such as. B. the carbon particles.

Preferably, the (respective) carbon component comprises at least 70% by weight of carbon.

The carbon component of at least one heating element (in particular several or all heating elements) may be present in the form of carbon black and / or graphite and / or graphene and / or carbon fibers and / or carbon nanotubes.

Preferably, the carbon component comprises at least one

Heating element (preferably several or all heating elements) at least 50 wt .-%, more preferably at least 80 wt .-%, even more preferably at least 90 wt .-% of carbon.

The polymer component of at least one heating element (preferably several or all heating elements) is in particular in the form of an electrically insulating polymer component.

In embodiments, the polymer component may comprise at least one

Heating element (preferably several or all heating elements) have a first polymer component based on ethylene acetate (copolymer) and / or ethylene acrylate (copolymer) and / or a second polymer component based on polyolefin, in particular polyethylene and / or polypropylene, and / or polyester and / or polyamide and / or fluoropolymer. The term "subcomponent" is intended here in particular for Distinction between first and second polymer subcomponent can be used. The respective subcomponent can form either partially or completely the polymer component. The ethylene acrylate may be ethyl methyl acrylate or ethylene ethyl acrylate. In which

Ethylene acetate may be ethylene vinyl acetate. The polyethylene may be high density polyethylene, medium density polyethylene, low density polyethylene. The fluoropolymer may be PFA (copolymer of tetrafluoroethylene and perfluoropropyl vinyl ester) MFA (copolymer of tetrafluoroethylene and perfluorovinyl ester), FEP (copolymer of tetrafluoroethylene and hexafluoropropylene), ETFE (copolymer of ethylene and tetrafluoroethylene) or PVDF (polyvinylidene fluoride) act.

In embodiments, the first polymer subcomponent may include at least one heating element (preferably, several or all of the heating elements), as shown in FIG

WO 2014/188190 AI (described as a first-electrically insulating material) may be formed. The second polymer subcomponent can likewise be formed as described in WO 2014/188190 A1 (as a second-electrically insulating material).

The (respective) polymer layer and / or a corresponding substance to be formed out (eg paste) for the production thereof may (in particular

crystalline binder) comprise at least one polymer, preferably based on at least one olefin; and / or at least one copolymer of at least one olefin and at least one monomer which can be copolymerized therewith, e.g. As ethylene / acrylic acid and / or

Ethylene / ethyl acrylate and / or ethylene / vinyl acetate; and / or at least one polyalkenamer (polyacetylene or polyalkenylene), such as. For example, polyoctenamer;

and / or at least one, in particular melt-deformable, fluoropolymer, such as. As polyvinylidene fluoride and / or copolymers thereof.

In general, the (respective) polymer layer or a to the

Preparation of the polymer layer used substance (paste), as in

DE 689 23 455 T2, be formed. This applies in particular also to their production and / or specific composition. For example, this also applies to possible binders (in particular according to p. 4, second paragraph and p. 5, 1st paragraph of DE 689 23 455 T2) and / or solvents (especially according to p. 5, 2 nd paragraph and p. 6 2nd paragraph of DE 689 23 455 T2). First and / or second conductive layer (metal layer) and / or the polymer layer of at least one heating element (preferably several or all heating elements) can in principle be designed as described in WO 2014/188190 A1 (as first conductor, second conduction and heating element) (apart from the air channels according to the invention).

The polymer layer of at least one heating element (preferably several or all heating elements) is preferably over at least 20%, preferably at least 50%, more preferably at least 80% of its side facing the first conductive layer (metal layer) (without consideration of

Fluid channel openings) with the first conductive layer (metal layer) in contact. Alternatively or additionally, the polymer layer over at least 20%, preferably at least 50%, more preferably at least 80% of its the second conductive layer (metal layer) facing side (without

Considering fluid channel openings) to be in contact with the second conductive layer (metal layer). By such (comparatively large) contacting surface between the conductive layers (metal layers) (metal plates) and the heating conductor layer (polymer layer), a

comparatively high power density can be achieved.

The polymer layer of at least one heating element (preferably several or all heating elements) is preferably a PTC resistor. As a result, a self-regulation of the heat output can be made possible, which simplifies the control and in particular increases the safety during operation.

The above object is further achieved by a method for

Production of an air heater, in particular of the above type, wherein at least a first and a second heating element are provided or manufactured, the heating elements each having a first conductive layer, in particular a first metal layer, a second conductive layer, in particular a second metal layer, a polymer layer the polymer layer a

Polymer component and a conductive carbon component include, wherein the heating elements are arranged so that they form between them a gap through which air can flow to their heating. Preferably, the polymer layer of at least one heating element

(Preferably, several or all heating elements) applied in an appropriate form on the first and / or second conductive layer (metal layer), in particular applied directly (alternatively via an intermediate layer between

Polymer layer and first and second conductive layer, in particular

Metal layer).

In embodiments, at least three, preferably at least five, heating elements may be provided with corresponding (eg, at least four) spaces.

A diameter of the gap between the first and second heating elements may be greater than a thickness of the first and / or second

Heating element.

On the respective conductive layer of at least one heating element

(Preferably, several or all heating elements), at least one projection, preferably at least one rib and / or at least one fin, be provided (to increase the heat transfer surface).

The above object is further achieved by a method for

Operating an air heater of the above type, wherein air flows through the at least one gap and is thereby heated.

The above object is further achieved by using a

Air heater of the type described above for heating air,

in particular in a motor vehicle, preferably for one

Motor vehicle interior.

The air heater is preferably for low-voltage operation

(eg <100 volts or <50 volts).

Further embodiments emerge from the subclaims.

The invention will be described with reference to embodiments, which are explained in more detail with reference to the accompanying figures. Hereby show:

Fig. 1 is a schematic frontal view of an electric air heater according to the invention; FIG. 2 shows a schematic side view of the embodiment according to FIG. 1 in a sectional illustration; FIG. and

3 is a schematic side view of an alternative embodiment of an electric air heater according to the invention in a sectional view analogous to FIG. 2.

In the following description, the same reference numerals are used for identical and equivalent parts.

Fig. 1 shows a frontal view of an air heater according to the invention.

This includes several (specifically six, but this is not mandatory)

Heating elements 9a-9f. Each of the heating elements 9a has a first conductive layer 10a-10f, a second conductive layer 1a-1f and a polymer layer 12a-12f. The respective first and second conductive layer is connected to electrical

Contacts 15a, 15b connected. Between the heating elements 9a-9f are

Intermediate spaces (fluid channels) 16a-16e formed. Through these spaces 16a-16e, the air flows to their heating (in Fig. 1 in the plane of the paper in or out of the paper plane). A further intermediate space 16f may optionally be provided outside of a (peripheral) heating element (heating element 9f in this case).

In the sectional view according to FIG. 2, in particular, the air flow is indicated by an arrow 14.

The respective conductive layer is in particular a metal layer (preferably of aluminum or an aluminum alloy). The respective polymer layer is a layer based on polymer with a carbon content. The polymer layer has a PTC behavior.

The alternative embodiment according to FIG. 3 differs from FIG

Embodiment of FIG. 1, characterized in that the heating elements do not extend along the direction of air flow (see FIG. 2), but perpendicular thereto, so that in the illustration of FIG. 3, only one heating element 9a can be seen, since the other heating elements through this Heating element to be covered. Also For example, six heating elements can be present here again. The

Gaps are also hidden by the heating element 9a.

It should be noted at this point that all parts described above, taken alone and in any combination, especially in the

Drawings shown details are claimed as essential to the invention. Variations thereof are familiar to the person skilled in the art.

LIST OF REFERENCE NUMBERS

9a-9f heating element

10a-10f First conductive layer (metal layer)

l la-l lf Second conductive layer (metal layer)

12a-12f polymer layer

14 arrow

15a, 15b contact

16a-16f gap (fluid channel)

Claims

claims

1. An electric air heater, in particular for a motor vehicle, comprising a first heating element (9a) and at least one second heating element (9b), the heating elements (9a, 9b) each having a first conductive layer, in particular a first metal layer (10a, 10b), a second conductive layer, in particular a second metal layer (IIa, IIb), and a

Polymer layer (12a, 12b), wherein the polymer layer (12a, 12b) comprises a polymer component and a conductive carbon component include,

wherein between the heating elements (9a, 9b), an intermediate space (16a) is formed through which air can be flowed to its heating.

2. Air heater according to claim 1,

d a d u rch e ke n ze i c h n et that,

first (9a) and / or second (9b) heating element at least in

Extend substantially along an air flow direction and / or extend at an angle to the air flow direction, for. B at an angle less than or equal to 90 ° and greater than 0 °, in particular greater than 10 °.

3. Air heater according to claim 1 or 2,

d a d u rch e ke n ze i c h n et that

the respective first (10a, 10b) and / or second (IIa, IIb) conductive layer is formed as a plate, in particular metal plate, and / or has a thickness of at least 0.1 mm, preferably at least 0.5 mm, more preferably at least 1 , 0 mm and / or at most 5.0 mm, preferably at most 3.0 mm.

4. Air heater according to one of the preceding claims,

d a d u rch e ke n ze i c h n et that

the respective first (10a, 10b) and / or second (IIa, IIb) conductive layer and / or the polymer layer (12a, 12b) are at least substantially planar.

5. Air heater according to one of the preceding claims, d a d u r c h e c e n c e n e c h n et that

at least three (9a-9c), preferably at least five (9a-9e)

Heating elements with corresponding spaces (16a-16d) are provided.

6. Air heater according to one of the preceding claims,

d a d u r c h g e ke n ze i c h n et that

a diameter of the gap (16a) between the first (9a) and the second (9b) heating element is greater than a thickness of the first and / or second heating element.

7. Air heater according to one of the preceding claims,

d a d u r c h e n c i n e c e n s that

on the respective conductive layer, at least one projection,

preferably at least one rib and / or at least one fin, is provided to increase the heat transfer surface.

8. Air heater according to one of the preceding claims,

d a d u r c h g e ke n ze i c h n et that

the carbon component is in particulate form and / or as a carbon skeleton.

9. Air heater according to one of the preceding claims,

d a d u r c h e n c i n e s that

the carbon component is present in the form of carbon black and / or graphite and / or graphene and / or carbon fibers and / or carbon nanotubes.

10. Air heater according to one of the preceding claims,

d a d u r c h e n c i n e s that

the polymer component in the form of an electrically insulating

Polymer component is formed and / or a first polymer Part component based on ethylene acetate or ethylene acetate copolymer and / or ethylene acrylate or ethylene acrylate copolymer and / or a second polymer component based on polyolefin, in particular polyethylene and / or polypropylene, and / or polyester and / or polyamide and / or fluoropolymer ,

11. Air heater according to one of the preceding claims,

d a d u rch e ke n ze i c h n et that

the polymer layer (12a, 12b) is in contact with the first conductive layer over at least 20%, preferably at least 50%, more preferably at least 80% of its side facing the first conductive layer, and / or

over at least 20%, preferably at least 50%, more preferably at least 80% of its second conductive layer side facing the second conductive layer in contact.

12. Air heater according to one of the preceding claims,

d a d u rch e ke n ze i c h n et that

the polymer layer (12a, 12b) is a PTC resistor.

13. A method of operating an air heater according to any one of claims 1 to 12, wherein air flows through the at least one intermediate space and is thereby heated.

14. Use of an air heater according to one of claims 1 to 12 for heating air, in particular in a motor vehicle, preferably for a motor vehicle interior.