EP3085198A1

EP3085198A1 - Electrically heatable sheet-type element

Info

Publication number: EP3085198A1
Application number: EP14781910.6A
Authority: EP
Inventors: Andreas Gerken; Jürgen BÜHRING; Günter PRÖMPERS
Original assignee: Benecke Kaliko AG
Current assignee: Benecke Kaliko AG
Priority date: 2013-12-20
Filing date: 2014-10-10
Publication date: 2016-10-26
Anticipated expiration: 2034-10-10
Also published as: DE102013226911A1; EP3085198B1; WO2015090666A1

Abstract

Disclosed is an electrically heatable sheet-type element comprising an electrically conductive coating which is applied to an electrically insulating support layer, more specifically to at least one subarea of the support layer, in a mesh or grating structure between the electrodes that forms loops and knots. The total electrical resistance of the sheet-type element can be adjusted by varying the shape of the mesh or grating and by varying the thickness of the applied layer, said thickness being adapted to the shape of the grating.

Description

description

Electrically heated surface element

The invention relates to an electrically heatable surface element with an applied on an electrically non-conductive support layer and contacted via electrodes electrically conductive and designed as a resistance heating coating and a heating system and a heater thereof and a method for producing such a surface element.

Surface heating elements are known in many designs. Heated surfaces such as seat heaters today belong z. B. in many vehicles to the standard equipment. In addition to electric heating systems, which are not in a solid composite with the overlying decorative and seating surface, directly heatable materials are used, which have an integrated electric heating function. In addition to the application as heating, such elements can also be used as sensors, switches, antennas, etc. As electrical resistance heating can be used in principle any material that has current flow at an electrical resistance, which leads to the heating of this material. Common as seat heaters are still Litzenheizungen, so embedded in textile material, leather or synthetic leather heating wires that are prone to fractures, have relatively large unheated surfaces between the strands and can not be changed in terms of electrical resistance. Furthermore, electrically conductive textiles can be used as electrical resistance heating.

Thus, EP 1 835 786 A1 discloses a surface heating element with a fabric which has threads in weft and warp direction and in which at least a part of the threads are designed as electrically conductive threads and in groups to heating tapes are summarized. In this case, the electrically conductive threads of each group are electrically connected in an initial and an end region by a planar connecting device and the heating bands are electrically interconnected via the connecting devices. , The electrically conductive threads must be very thin enough to

Flexibility in e.g. Seat coverings. The production of such thin electrically conductive threads is difficult. In addition, overheating and cracks can occur.

WO 2007/031324 A1 discloses a heating element comprising at least one layer of a matrix of functional fibers, wherein the matrix is electrically conductive and / or heatable, can be connected via contact lines to a current or voltage source, comprises mutually electrically insulated conductive sections and at least partially exclusively non-metallic fibers as functional fibers, e.g. B. carbon fibers. The production is not easy and the resistance is limited by the components used.

Another possibility for producing a seat heating for motor vehicles is described for example in DE 42 33 118 A 1. Here, a fabric is used as a heating mat, which consists of carbon fibers, which have a relatively high electrical resistance. To supply this heating mat with electricity, are on the

Ends each lead or contact wires provided. One of

Contact wires are grounded, whereas another is energized. Due to the potential difference, a current flows through the carbon fibers of the fabric to the grounded contact wire and thereby generates heat. Such a heating mat theoretically allows a uniformly constant heat dissipation over the entire surface, but a concentration of heat development at certain locations with this heating mat is not possible. Also, the problem is that the request to the

Carbon fiber fabric is very high in terms of uniformity to achieve a truly uniform heat distribution. This in turn complicates the manufacture, as noted above. Another surface heating element is disclosed in DE 41 10 36 425 A1. Here, sinusoidal weft threads are provided in a knitted textile base material, which act as a heat conductor. To supply power to this heating conductor power supply conductors are provided, to which the heating conductors are each performed. As described, special attention must be paid to the contacting of the heating conductors with the

Power supply conductors are laid. This is achieved by a long contact distance, which is somewhat unfavorable.

DE 10 2012 000 445 AI discloses seat heating for a pad of a vehicle seat with at least one controllable by a control device and acted upon by electric current heating element, wherein the heating element has a heating layer, which is formed by a Heizlack. Thus, individual and demand-based heating elements should be produced in shape and size. Although this allows the geometry of the heating elements, but not set their electrical resistance.

DE 102005050459 B3 discloses a flexible surface heating element for seat heaters, with a heating field of conductive fibers, which are electrically conductively connected to a contact strip. At least one contact strip contains a proportion of conductors in the form of steel filaments and a proportion of conductors in the form of filaments of a higher conductivity than the steel filaments, wherein the two types of conductors electrically

are interconnected and by means of textile and / or metallic

Threads are held on a textile tape. The conductors of higher conductivity are wavy or meandering, crossing the respective steel conductors and with the

the former in contact. The higher conductivity conductors are above or below the steel filaments. As a result, the surface heating element is to be able to continue to operate in the event of breakage of single thin filaments without overheating. Of course, the production is very expensive.

DE 41 24 684 A1 discloses an integrated in an elastic carrier material

Surface heating element, consisting of substantially parallel heating wires, which are electrically connected at their ends and / or deflection with power supply conductors are. Each power supply conductor is designed as a flexible contacting strip with a plurality of individual conductors, which are electrically connected in parallel with the heating wires. This is an attempt to achieve greater flexibility for the electrodes / contact elements. Again, the production is quite complicated and the risk of overheating in fractures is not eliminated.

WO 2005/020246 A1 discloses a process for the production of electrically conductive, flexible fabrics, comprising the application of an aqueous, film-forming polymer composition comprising a binder B with a non-film-forming powder having core-shell morphology. This consists of the shell forming

Material of at least one noble metal or an alloy consisting predominantly of at least one precious metal. The polymer composition is in the form of a reticulated pattern on the surface of a flexible, planar

Carrier applied, the electric current does not conduct.

The object of the invention was therefore to provide a fracture-resistant and heat-resistant, heat-resistant surface element which can be well integrated into today's control systems in terms of its electrical properties and heating properties.

It was also the task of using a flexible and possibly also elastic electrically conductive flexible fabric as a decorative surface element in the vehicle interior to bring any number of such surface elements, each with different geometries by means of a commercial electronic seat heating control regulated to a defined surface temperature, So that the

Surface temperatures are the same in all heating surfaces and the desired temperature is achieved quickly compared to a standard seat heating.

This object is achieved by the features of the main claim. Further advantageous embodiments are disclosed in the subclaims. In this case, the electrically conductive coating on at least one partial surface of the carrier layer in a mesh and node-forming mesh or grid structure is applied between the electrodes and the total electrical resistance of the planar element by the shape of the mesh, grid or other pattern and by the adapted to the grid shape Application thickness of the coating adjustable.

By such surface elements there are heating mats which, for a given geometry, have an electrical resistance and thus their specific heat output, i. are adjustable in the achievable temperature and can be used for accurate temperature control with a standard commercial seat heating control, where usually the electrical resistance of the heating surfaces must be known and specified in close tolerances.

A typical task in this regard is e.g. the heating of an automobile seat with heating elements in the seat, in two seat side panels, in the backrest surface and in the two backrest side panels by means of a commercially available seat heating control. The heating surfaces are usually predominantly rectangular. The surface elements according to the invention can also be combined with any alternative heating mats, with the same commercial controls can be used for temperature control.

The commercially available seat heating control units are, for example, the seat heating control SM LC-1 from Continental Temic. This unit can control the temperature in parallel in two heating circuits or heating mats and is a single-circuit seat heating controller. It controls 2 heating mats, but only in a heating mat

Temperature sensor is installed. The second heating mat without temperature sensor is controlled with the same pulse-width-modulated power as the regulated heating mat.

It is regulated to a setpoint. The current actual value is supplied by the temperature sensor. For controlling the seat heating modules of a master control unit, a bidirectionally operated PWM interface (PWM = pulse width modulated) is used. The control technology of such seat heating control units allows error-free operation only within certain current limits. For example, the minimum current is greater than or equal to 2.1A and the maximum current is less than 12.8A. That means that at two

Surface heating elements, or heating mats (two heating circuits) and a supply voltage of 12 volts in a parallel circuit of the heating circuits must flow at least 1.05 A, which corresponds to a minimum resistance of 11.4 Ω according to R = U / I, or one

Maximum resistance of 0.94 Ω corresponds. For error-free operation, therefore, both heating circuits must have an electrical resistance between 0.94 and 11.4 Ω. The surface heating elements according to the invention can now be set in their resistance in a simple manner by the formation of the shape of the network or grid and by the order adapted to the lattice form job coating so that they can be easily operated with such a standard seat heating control. An advantageous development in this sense also consists in that, in addition, the width-height ratio and the electrode spacing of the surface element can be adjusted after its application as a parameter for determining the total electrical resistance. So z. As a shortening of the surface heating at constant Elektrodenab states to increase the resulting electrical resistance, since the electrically conductive network or grid lines as parallel

Resistances behave.

A further advantageous embodiment is that the electrically conductive

Coating is applied on the back of the carrier film forming decorative film or a decorative artificial leather or between a carrier layer and a decorative film as a topcoat. This simplifies the adaptation to the

Application and provides easy to process for the seat manufacturing

Components. One in the sense of a simple and process-reliable production particularly suitable

Process for producing an electrically heatable surface element according to the invention consists in that the electrically conductive coating is applied as an electrically conductive viscous paste in the form of a mesh or lattice structure on the support layer and then dried and cured. An advantageous embodiment of the method is that the dried mass of the applied electrically conductive viscous paste is about 10 g / m to 500 g / m ² .

Preferably, this is about 20 g / m 2 to 200 g / m ² , in particular about 30 g / m 2 to 80 g / m ² . This creates a secure adhesion of the mesh or grid structure while providing the required flexibility of the overall structure.

A further advantageous embodiment of the method is that the electrically conductive viscous paste is composed of

345 g of an aqueous aliphatic polyester-polyurethane dispersion with 50%

Solids content

6 g of an associative thickener,

- 258.75 g of particulate filler particles with dendritic form based on superficially silver-coated copper

- 86.25 g of finely divided particles of spherical or oblong shape

- 5 g of an isocyanate crosslinker based on trimeric hexamethylene diisocyanate with 21.8% content of free isocyanate groups

and mixed homogeneously while stirring with a dissolver at 800 rpm, preferably mixing the electrically conductive viscous paste to adjust the viscosity with distilled water, preferably in said mixture with at least 200 (215) g of distilled water.

This z. As artificial leather, consisting of a textile support and a single or multi-layer polymeric coating, for example based on PVC and / or polyolefins and / or polyurethane, printed on the free, visible textile side with the polymer composition described below. The textile used is a polyester fabric of 47 g / m basis weight. The coating composition is mixed with a desired

Evenly applied to the textile surface, so that the dried Mass of the applied coating composition according to the invention is about 50 g / m or 80 g / m ² . Subsequently, the coated flexible carrier is stepped in a

Hardened heating process by first 2 min at 80 ° C, then applied for 2 min at 100 ° C and then 2 min at 120 ° C. The mass of applied

Coating after the drying process is about 30 g / m ² or 50 g / m ² .

The pattern used is a diamond pattern with printed lines rotated 90 ° and with a line spacing of 7 mm and a line width of 1.5 mm.

Here, an electrically conductive paste is used, which is prepared in the following manner: 345 g of an aqueous aliphatic polyester-polyurethane dispersion (with 50%

Solids content) are admixed with 6 g of an associative thickener, 258.75 g of dendritic-form particulate filler particles based on silver-coated copper and 86.25 g of spherical or elongated particulate particles and 5 g of an isocyanate crosslinker based on trimeric

Hexamethylene diisocyanate with 21.8% content of free isocyanate groups homogeneously mixed with stirring with a dissolver at 800 revolutions / minute. Optional to

To adjust the viscosity, 215 g of distilled water are additionally added here.

The contacting of the electrically conductive fabrics via trained as contact strips electrodes which are provided with a hot melt adhesive. These contact strips are prefixed with an iron or a heated roller or roller on the electrically conductive surface of the decorative film and subsequently impregnated with the same electrically conductive paste over the entire electrode length by means of a pipette, so that ideally an intimate electrically conductive connection between electrode bands and the resistance heating arises.

The conductivity paste is then cured thermally in an oven at 80 ° C for 4 minutes and then at 120 ° C for 2 minutes.

A further advantageous embodiment of the method in the sense of simplification is that the electrically conductive viscous paste is applied to the carrier layer by means of a screen-printing method, namely via a with a usually photo-technical or via laser applied printed pattern screen and by means of a

Screen printing roller. The desired application weights of the electrically conductive

Polymer composition can be adjusted on the coating thickness of the coating of the screen, on the squeegee pressure and the viscosity of the electrically conductive paste.

In a special way can be used for the construction of heatable objects with complicated surfaces, a heating system with one or more inventive heatable surface elements, in which the surface elements in series and / or

Parallel connection as fixed resistors with a simple and inexpensive

Control unit connected and connected to a heating control, the

Control unit has fewer outputs for control or current control than heated surface elements must be controlled. Of course, the output here always means a two-pole current output which can supply / regulate a consumer with phase and neutral. In particular, such a heating system can be used as a heater for a vehicle seat, wherein at least one of the surfaces of the seat, the seat side bolsters, the backrest or the backrest sidewalls are connected as a heatable surface element in the heating system.

Reference to an embodiment of the invention will be explained in more detail. Show it

Fig. 1 is an application fiction, according to electrically heatable

Surface elements in a heating system

Fig. 2 is a mesh or grid shape of a fiction, contemporary electrical

conductive coating of a heatable surface element

Fig. 3 shows another network or lattice form an inventive

electrically conductive coating of a heatable

surface element

Fig. 4 circuit of a heating system with fiction, contemporary heatable

Surface elements in detail

Fig. 5 shows the results of a temperature measurement of the seat surfaces with a thermal camera

Fig. 6 is a negative pressure for the screen printing process another

Formation of the electrically conductive coating on a

leatherette

Fig. 7 shows a further mesh or grid shape of an inventive

electrically conductive coating of a heatable

surface element

Fig. 8 shows yet another mesh or grid shape of an electrically conductive coating according to the invention a heatable

surface element

Fig. 1 shows schematically an application fiction, in accordance with electrically heatable surface elements in a heating system 1 for a car seat 2 with a plurality of such surface elements 3 to 8. The electrically heatable surface element 3, 4, 5, 6, 7 and 8 are at the two outputs 9 and 10 of a known seat heating control unit 11 connected, which can regulate the temperature in parallel in two heating circuits or heating mats and is designed as a single-circuit seat heater controller. It usually controls with its two power outputs only two heating mats, only in a heating mat, a temperature sensor is installed.

Here exactly shows the particular advantage of the invention. Namely, at each exit of this simple seat heating control unit 11, not only a heating mat is connected as usual, but in each case three electrically heatable surface elements according to the invention, which are thus interconnected to a heating system of a total of six "heating mats." The surface heating elements according to the invention can in fact be connected by adjusting the shape of the mesh or grid and by adjusting the coating thickness of the coating to match the grid shape, they will be able to be easily operated with such a standard seat heating control unit. It thus creates a heating system in which the seat surface 3, the seat side bolsters 4 and 5, the backrest 6 and backrest side bolsters 7 and 8 are heated and provide a very comfortable seating experience at low temperatures, without special customized expensive control units are required.

In this embodiment, the electrically heatable surface elements have the following dimensions:

Seat 3 - »445 mm x 280 mm

Rest 6 -> 660 mm x 300 mm

Seat side panels 4, 5 390 mm x 111 mm

Backrest side panels 7, 8 360 mm x 90 mm

Since the simple seat heating control unit 11 only two heating circuits 12 and 13 can be controlled, the surface elements of the backrest side walls must be parallel to those of the back and the surface elements of the seat side walls parallel to the surface element of the seat.

For error-free control of the two heating circuits by the seat heating control 11, the two heating circuits, namely the seat 3 and seat side walls 4 and 5 existing heating circuit 12 and the backrest 6 and backrest side walls 7 and 8 existing heating circuit 13 each have an electrical resistance between 1 and 5.75 Ω, which is provided by appropriate design of the heated surface elements. For this purpose, the illustrated two heating circuits 12 and 13 each have electrical resistances of 1.96 or 2.65 Ω, which are provided by the fact that the individual electrically heatable surface elements having 30 and 50 g / m ² conductive coating in lattice structure. In this case, the electrically conductive coating of the seat side cheeks 4 and 5 with the method according to the invention, here using the screen printing process, on applied to a synthetic leather, wherein the dried mass of the applied electrically conductive viscous paste is about 30 g / m. These 30g / m ² printing paste resulted in the present network or lattice structure 14, an electrical resistance of 16 Ω between the terminal electrodes.

The network or lattice structure 14 selected here for the seat side walls 4 and 5 is shown enlarged in FIG. 2 and is wave-shaped, with wavy lines 15 and 16 intersecting each other with their flanks 17 and 18 crossing nodes 19 and the latter are formed thickened compared to the web width, namely by concave curves in the corners of crossing webs.

The electrically conductive coating of the backrest side walls 7 and 8 are with the screen printing process according to the invention in the form of a grid 14 on a

Applied artificial leather, wherein the dried mass of the applied electrically conductive viscous paste is about 50 g / m. This 50 g / m ² printing paste resulted in the present network or lattice structure 14, an electrical resistance of 13 Ω between the terminal electrodes.

The electrically conductive coatings of the seat surface 3 and the backrest surface 6 are also applied to the said method in the form of a grid on a synthetic leather, wherein the dried mass of the applied electrically conductive viscous

Paste is about 30 g / m.

The network or grid 20 chosen here for the seat 3 and the backrest surface 6 is shown enlarged in FIG. 3 and is made up of square meshes, with the nodal points 23 formed by intersecting webs 21 and 22 likewise being in each case

Compared to the ridge width are formed thickened, namely by concave curves in the corners of crossing ridges. These 30g / m ² printing paste resulted in the present network or lattice structure 20, an electrical resistance of 2.6 Ω for the seat 3 as a heated surface element and 2.0 Ω for the back surface 6 as a heatable surface element, measured in each case between the connection electrodes. The surfaces of the seat and backrest are different in size, as described above and also shown in Fig. 4, so that in combination of the size, the coating amount and the lattice form the said different resistance values.

The first heating circuit 12 is formed by combining the heatable surface elements of the seat side cheeks and the seat surface and the second heating circuit 13 by combining the heatable surface elements of the backrest side walls and the back surfaces. The type of interconnection of the heating mats is shown in the figure below. By adjusting the electrical resistances of the heating mats is the

Using the simple seat heating control with only two outputs easily possible, as already explained above. The calculated and actually resulting total resistance of the parallel and series connection of the heatable surface elements in this embodiment are listed in Table 1 below.

Seat 3 seat side bolsters back 6 backrest 4, 5 side bolsters 7,8

Resistance 2.6 Ω 16 Ω for each 2.0 Ω 13 Ω for each cheek

cheek

Type of imitation leather Printed imitation leather Printed imprinted imitation leather

Imitation leather imitation leather

Coverage 30g / m ⁱ 3ög / m ² 50g / m ⁱ

Heating circuits Heating circuit 12 Heating circuit 13

Heating circuit resistance 1.96 Ω 1.5 Ω

Table 1, Summary of the Circuit and Resistance Values

The circuit of the heating system, Fig. 4 again in detail, with the

Combination of parallel and series connection of the connected to the respective outputs 9 and 10 heated surface elements is shown.

The results of a temperature measurement of the seat surfaces with a thermal camera is shown in FIG. 5. It becomes clear that, on the corresponding surfaces, after a very short time at the various setting levels of the seat heating control system

Target temperature is reached and kept substantially constant. Fig. 6 shows a print negative for the screen printing method of another embodiment of the electrically conductive coating on a synthetic leather, in which the net or

Grid structure 24 is formed as an expanded metal warped quadrilateral. Here are the bright lines which later became the grid forming coating lines.

Fig. 7 shows a different embodiment of the electrically conductive coating on a synthetic leather, in which the mesh or grid structure 25 is wave-shaped and each side by side extending wavy lines with their troughs or

Wave mountains crashing together forming nodes.

Fig. 8 shows a further embodiment of the electrically conductive coating on a synthetic leather, in which the mesh or grid structure 26 is formed like a sawtooth parallel running and also has short sawtooth connection webs between the parallel main webs.

This inventively different configurations of the shape of the network or grid, the associated order strength of the coating and the adjusted width width ratio and electrode spacing of the surface element lead to a defined adjustment of the resulting electrical resistance on the circumstances of the seat heating control, so easily complicated control tasks a simple standard seat heating control can be operated.

LIST OF REFERENCE NUMBERS

(Part of the description)

I heating system

2 automobile seat

3 electrically heated surface element / seat

4 electrically heated surface element / seat side bolster

5 electrically heatable surface element / seat side bolster

6 electrically heatable surface element / backrest

7 electrically heatable surface element / backrest sidewall

8 electrically heatable surface element / backrest sidewall

9 exit

10 output

I I seat heating control unit

12 heating circuit

13 heating circuit

14 network or grid structure

15 wavy line

16 wavy line

17 flank of the wavy line

18 flank of the wavy line

19 node

20 mesh or grid structure

21 footbridge

22 footbridge

23 node

24 mesh or grid structure

25 mesh or grid structure

26 mesh or grid structure

Claims

claims

1. Electrically heatable surface element (3, 4, 5, 6, 7, 8) with an applied on an electrically non-conductive support layer and contacted via electrodes electrically conductive and designed as a resistance heating coating, characterized in that the electrically conductive coating on at least one partial surface the carrier layer is applied in a mesh and node-forming mesh or grid structure (14, 20, 24, 25, 26) between the electrodes, wherein the total electrical resistance of the planar element (3, 4, 5, 6, 7, 8) through the Form of the network or grid and by the order adapted to the grid shape job thickness of the coating is adjustable.

2. Electrically heatable surface element according to claim 1, wherein in addition the width-height ratio and the electrode spacing of the surface element after its application as parameters for determining the total electrical resistance are adjustable.

3. Electrically heatable surface element according to claim 1 or 2, wherein the mesh or grid structure (20) has rectangular or square mesh.

4. Electrically heatable surface element according to claim 1 or 2, wherein the mesh or grid structure (24) is formed as an expanded metal warped quadrilateral.

5. Electrically heatable surface element according to claim 1 or 2, wherein the mesh or grid structure (25) is wave-shaped, wherein in each case juxtaposed wavy lines with their troughs or wave crests

crashing to form nodes.

6. Electrically heatable surface element according to claim 1 or 2, wherein the network or lattice structure (14) is wave-shaped, wherein each transverse to each other extending wavy lines with their flanks (17, 18) crossing nodes (19) form.

7. Electrically heatable surface element according to one of claims 1 to 6, wherein the nodes are formed thickened compared to the ridge width, in particular by concave curves in the corners of crossing ridges.

8. Electrically heatable surface element according to one of claims 1 to 7, wherein the electrically conductive coating on the back of the carrier layer forming decorative film or a decorative artificial leather or between a

Carrier layer and a decorative film is applied as a cover layer.

9. A method for producing an electrically heatable surface element according to one of Anspüche 1 to 7, characterized in that the electrically conductive

Coating as electrically conductive viscous paste in the form of a network or

Grid structure applied to the carrier layer and then dried and cured.

10. The method of claim 9, wherein the dried mass of the applied electrically conductive viscous paste is about 10 g / m to 500 g / m ² .

11. The method of claim 9 or 10, wherein the electrically conductive viscous paste is composed of

- 345 g of an aqueous aliphatic polyester polyurethane dispersion with 50% solids content

6 g of an associative thickener,

- 86.25 g of finely divided particles of spherical or oblong shape

and with stirring with a dissolver at 800 revolutions / minute homogeneous is mixed.

12. The method of claim 11, wherein the electrically conductive viscous paste for

Setting the viscosity is mixed with distilled water, preferably in said mixture with at least 200 (215) g of distilled water.

13. The method according to any one of claims 9 to 11, wherein the electrically conductive viscous paste is applied by a screen printing method on the carrier layer.

14. heating system with a plurality of heatable surface elements (3, 4, 5, 6, 7, 8) according to one of claims 1 to 8, wherein the surface elements connected in series and / or parallel connection as fixed resistors to a control unit (11) and to one

Heating control are connected, wherein the control unit (11) has fewer outputs for controlling or current control must be controlled as a heated surface elements.

15. A heater for a vehicle seat, wherein at least one of the surfaces of the seat, the seat side bolsters, the backrest or the backrest sidewalls is connected as a heatable surface element in a heating system according to claim 14.