PTC heating module and a method for producing the PTC heating module

Abstract

The disclosure relates to a PTC heating module for heating a fluid and a method for producing such a PTC heating module. The PTC heating module includes a plurality of PTC thermistors having main surfaces disposed opposite to one another and spaced apart relative to one another in a thickness direction. The PTC thermistors are arranged between two contact plates next to one another transversely to the thickness direction and spaced apart relative to one another. The main surfaces of the PTC thermistors are electrically contacted with a contact surface of the two contact plates. At least one dielectric function element is arranged between the two contact plates and laterally sealingly engages about the respective PTC thermistors to at least partially fill a hollow space between the two contact plates and facilitate enlarging a creepage distance between the two contact plates within the hollow space.

Claims

1. A PTC heating module for heating a fluid, comprising: a plurality of PTC thermistors each having two main surfaces, wherein the two main surfaces of the plurality of PTC thermistors are located opposite to one another and spaced apart relative to one another in a thickness direction, two contact plates each provided with a contact surface, between which the plurality of PTC thermistors are arranged transversely to the thickness direction next to one another and spaced apart relative to one another, wherein the two main surfaces of the plurality of PTC thermistors are electrically contacted with the contact surface of a respective one of the two contact plates, and at least one dielectric function element, arranged between the two contact plates and laterally sealingly engaged about and sealingly adjoins the plurality of PTC thermistors, such that a hollow space between the two contact plates in the thickness direction is at least partly filled out with the at least one dielectric function element and a creepage distance between the two contact plates within the hollow space is enlarged, and wherein the at least one dielectric function element is a dielectric coating, and the hollow space is at least partially filled out with the dielectric coating in the thickness direction.

2. The PTC heating module according to claim 1, further comprising an insulation plate.

3. The PTC heating module according to claim 2, wherein the insulation plate, transversely to the thickness direction, projects out of the hollow space towards an outside such that in an edge region of the two contact plates an air gap between the two contact plates is enlarged.

4. The PTC heating module according to claim 1, wherein the dielectric coating is fixed on each of the contact surfaces of the two contact plates around the plurality of PTC thermistors, and wherein the hollow space between the two contact plates in the thickness direction is partly filled out by the dielectric coating such that an air gap is defined transversely to the thickness direction in the hollow space.

5. The PTC heating module according to claim 1, wherein: the dielectric coating is fixed on each of the contact surfaces of the two contact plates around the plurality of PTC thermistors, wherein the hollow space between the two contact plates in the thickness direction is partly filled out such that the dielectric coating at least partially covers the plurality of PTC thermistors in the thickness direction, or the dielectric coating is fixed on each of the contact surfaces of the two contact plates around the plurality of PTC thermistors, wherein the hollow space between the two contact plates in the thickness direction is completely filled out, or the dielectric coating is fixed on each of the contact surfaces of the two contact plates around the plurality of PTC thermistors, wherein the hollow space between the two contact plates in the thickness direction is partly filled out and the plurality of PTC thermistors are cladded by the dielectric coating transversely to the thickness direction.

6. The PTC heating module according to claim 1, wherein the dielectric coating laterally dads the at least one contact plate and is disposed outside of the contact surface at least in one region, such that in an edge region of the two contact plates an air gap between the two contact plates is enlarged.

7. The PTC heating module according to claim 4, wherein the dielectric coating completely dads the at least one contact plate around the plurality of PTC thermistors and the two contact plates are electrically insulated towards an outside.

8. The PTC heating module according to claim 1, further comprising: a dielectric basic coating fixedly bonded on an end face of at least one of the two contact plates, the end face located opposite to the contact surface of the at least one contact plate, wherein the dielectric basic coating electrically insulates the at least one contact plate towards an outside, or a dielectric insulation cladding structured and arranged to clad the two contact plates on a plurality of sides and electrically insulate the two contact plates towards an outside.

9. The PTC heating module according to claim 1, further comprising an electrically conductive contact base arranged between a respective one of the plurality of PTC thermistors and at least one of the two contact plates, the electrically conductive contact base having a support face that is smaller than the two main surfaces of the respective PTC thermistor, and wherein the respective PTC thermistor projects from the electrically conductive contact base transversely to the thickness direction.

10. The PTC heating module according to claim 9, wherein the electrically conductive contact base has a thickness defined in the thickness direction that is smaller than a layer thickness of a dielectric coating of the at least one dielectric function element defined in the thickness direction on at least one of the two contact plates, and wherein the electrically conductive contact base, transversely to the thickness direction, is completely cladded by the dielectric coating on the at least one contact plate.

11. The PTC heating module according to claim 1, further comprising a dielectric basic coating disposed on a respective end face of the two contact plates disposed opposite to the contact surface, wherein the dielectric basic coating electrically insulates the two contact plates towards an outside.

12. The PTC heating module according to claim 1, wherein the dielectric coating, transversely to the thickness direction, projects out of the hollow space towards an outside such that in an edge region of the two contact plates an air gap between the two contact plates is enlarged.

13. The PTC heating module according to claim 2, wherein the insulation plate is composed of ceramic.

14. The PTC heating module according to claim 9, wherein the dielectric coating is disposed on the contact surface of the at least one contact plate, and wherein the electrically conductive contact base has a thickness in the thickness direction that is smaller than a layer thickness of the dielectric coating in the thickness direction.

15. A method for producing a PTC heating module, comprising: providing a plurality of PTC thermistors each having two main surfaces disposed opposite to one another and spaced apart from one another in a thickness direction of the plurality of PTC thermistors; arranging the plurality of PTC thermistors between two contact plates next to one another transversely to the thickness direction and spaced apart relative to one another; joining the plurality of PTC thermistors with the two contact plates, wherein the plurality of PTC thermistors are joined simultaneously with the two contact plates or are joined first with one of the two contact plates and then with the other of the two contact plates, such that the two main faces of the plurality of PTC thermistors are indirectly or directly electrically contacted with a respective contact surface of the two contact plates, and wherein prior to the joining or after the joining of the plurality of PTC thermistors with the two contact plates, applying at least one dielectric function element comprising a dielectric coating onto the respective contact surface of at least one of the two contact plates, wherein applying the at least one dielectric function element comprising the dielectric coating includes at least partially filling a hollow space between the two contact plates in the thickness direction and laterally sealingly engaged about and sealingly adjoins the plurality of PTC thermistors with the dielectric coating.

16. The method according to claim 15, wherein applying the dielectric coating further includes: applying the dielectric coating on the at least one contact plate in at least one region outside of the respective contact surface such that the at least one contact plate is laterally or completely cladded by the dielectric coating, or applying a dielectric basic coating onto an end face of the at least one contact plate located opposite to the respective contact surface, or applying a dielectric insulation cladding onto the two contact plates to clad the two contact plates on a plurality of sides.

17. The method according to claim 15, wherein the dielectric coating is applied after the joining of the plurality of PTC thermistors with the two contact plates, and wherein applying the dielectric coating includes injecting or over-moulding or spraying-in a dielectric material in the hollow space or by dipping into a dielectric material or by anodizing with a dielectric material.

18. The method according to claim 15, wherein: the dielectric coating is applied by over-moulding or spraying-on a dielectric material or by dipping into a dielectric material or by anodizing with a dielectric material or by gluing on a film of a dielectric material around the plurality of PTC thermistors after the joining of the plurality of PTC thermistors with a respective one of the two contact plates, or the dielectric coating is applied by over-moulding or by spraying-on a dielectric material or by anodizing with a dielectric material or by dipping into a dielectric material or by gluing-on a film of a dielectric material around a plurality of place holder elements prior to the joining of the plurality of PTC thermistors with the two contact plates, and thereafter removing the plurality of place holder elements and then the plurality of PTC thermistors are placed in positions kept by the plurality of place holder elements and joined with the two contact plates.

19. The method according to claim 15, further comprising arranging an electrically conductive contact base between a respective one of the plurality of PTC thermistors and at least one of the two contact plates, wherein the electrically conductive contact base has a support face that is smaller than a corresponding one of the two main faces of the respective PTC thermistor such that the respective PTC thermistor projects outwardly from the electrically conductive contact base transversely to the thickness direction.

20. A PTC heating module for heating a fluid, comprising: a plurality of PTC thermistors respectively having two main surfaces disposed opposite to one another and spaced apart relative to one another in a thickness direction; two contact plates arranged spaced apart from one another in the thickness direction, the plurality of PTC thermistors arranged between the two contact plates next to and spaced apart from one another transversely to the thickness direction, wherein the two main surfaces of the plurality of PTC thermistors are electrically contacted with a respective contact surface of the two contact plates; and a dielectric coating arranged between the two contact plates and laterally sealingly engaged about and sealingly adjoins the plurality of PTC thermistors, wherein the dielectric coating is fixed on the contact surface of at least one of the two contact plates and at least partially fills a hollow space between the two contact plates to facilitate increasing a creepage distance between the two contact plates within the hollow space.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) It shows, in each case schematically

(2) FIGS. 1 to 12 illustrate sectional views each of a deviatingly configured PTC heating module according to the invention.

DETAILED DESCRIPTION

(3) FIG. 1 shows a sectional view of a PTC heating module 1 according to the invention for heating a fluid. The PTC heating module 1 comprises multiple PTC thermistors 2 consisting of a PTC thermistor material and two contact plates 3a and 3b, with which the PTC thermistors 2 are stacked in the thickness direction 4. The respective PTC thermistors 2 each comprise two main surfaces 5a and 5b which located opposite one another and in thickness direction 4 are spaced apart relative to one another. The main surfaces 5a and 5b are directly or indirectly in electrical contact with a contact surface 6a and 6b of the respective contact plate 3a and 3b each so that the respective PTC thermistor 2 is electrically contacted with the contact plates 3a and 3b. The contact plates 3a and 3b can be connected to an external voltage source, for the purpose of which on the contact plates 3a and 3b a contact element 7a and 7b each is formed or fixed. In this exemplary embodiment, the PTC heating module 1 comprises a housing 8 which provides cladding for the two contact plates 3a and 3b and the PTC thermistors 2 arranged in between. On the housing 8, a rib structure 9—only schematically indicated here—is fixed, through which a fluid such as air can flow. The respective PTC thermistors 2 are arranged transversely relative to the thickness direction 4 next to one another and spaced apart relative to one another, so that between the two contact plates 3a and 3b a hollow space 10 is formed.

(4) Furthermore, the PTC heating module 1 comprises a function element 11 which in this exemplary embodiment is a dielectric coating 12. The dielectric coating 12 is fixed on the contact surfaces 6a and 6b of the contact plates 3a and 3b round about the PTC thermistors 2 in a firmly bonded manner and completely fills out the hollow space 10. The coating 12 sealingly adjoins the thermistors 2 laterally, so that no creepage currents can flow through a lateral air gap between the dielectric coating 12 and the PTC thermistors 2. A creepage distance between the two contact plates 3a and 3b is enlarged within the hollow space 10. In this exemplary embodiment, the dielectric coating 12 comprises two dielectric material part layers 13a and 13b, of which each is fixed on the contact surface 6a and 6b of the respective contact plate 3a and 3b. In the PTC heating module 1, the two dielectric material part layers 13a and 13b are arranged in thickness direction 4 on one another and form a contiguous material layer 13, so that the hollow space 10 is completely filled out in the thickness direction 4.

(5) The dielectric coating 12 or the material layers 13a and 13b completely clad in this exemplary embodiment the respective contact plates 3a and 3b round about the PTC thermistors 2, so that the contact plates 3a and 3b are covered by the dielectric coating 12 or by the material part layers 13a and 13b also laterally and on their end faces 14a and 14b. Because of this, an air gap in an edge region 15 of the respective contact plates 3a and 3b is reduced. Furthermore, the dielectric coating 12 or the material part layers 13a and 13b are applied onto the end faces 14a and 14b and electrically insulate the two contact plates 3a and 3b from the housing 8 of the PTC heating module 1. Here, the dielectric coating 12 can be heat-conductive so that the heat generated in the PTC thermistors 2 can be emitted to the housing 8 and further via the rib structure 9 to the fluid flowing through the rib structure 9 via the contact plates 3a and 3b and the dielectric coating 12.

(6) In the following, deviating configurations of the PTC heating module 1 are explained. For the sake of clarity, the housing 8 and the rib structure 9 are not shown in FIG. 2 to FIG. 12. However, these can be embodied in the same way as in the PTC heating module 1 in FIG. 1. Furthermore, in some embodiments, no insulation is shown on the end faces 14a and 14b. It goes without saying that this insulation—in the case that it is not otherwise provided—can be realised by a basic coating or an insulation cladding.

(7) FIG. 2 shows a sectional view of the alternatively configured PTC heating module 1 with the function element 11 in the form of the dielectric coating 12. In the PTC heating module 1 shown here, the dielectric coating 12 is formed by a single material layer 17, which can be produced for example by injecting a dielectric material—preferentially plastic—into the hollow space 10. In this exemplary embodiment, the dielectric coating 12 or the material layer 12 engages about the respective contact plates 3a and 3b laterally, so that an air gap in the edge region 15 of the contact plates 3a and 3b is enlarged. Here, no dielectric coating 12 is applied onto the end faces 14a and 14b.

(8) FIG. 3 shows a sectional view of the alternatively configured PTC heating module with the function element 11 in the form of the dielectric coating 12. In this exemplary embodiment, the dielectric coating 12 comprises the material part layers 13a and 13b, which in contrast with the embodiment in FIG. 1 are not contiguous. Because of this, the hollow space 10 is filled out only partially in the thickness direction 4. The material part layers 13a and 13b engage about the contact plates 3a and 3b laterally, so that an air gap 22 in the edge region 15 is enlarged. Here, no dielectric coating 12 is applied onto the end faces 14a and 14b.

(9) FIG. 4 shows a sectional view of the alternatively configured PTC heating module 1 with the function element 11 in the form of the dielectric coating 12. In this exemplary embodiment, the dielectric coating 12 is formed by the contiguous material layer 17 which completely separates the PTC thermistors 2 in the hollow space 10 transversely to the thickness direction 4 and the contact surfaces 6a and 6b round about the respective PTC thermistors 2 from air. However, the hollow space 10 is partly filled out in the thickness direction 4 so that between the contact plates 3a and 3b within the contiguous material layer 17 an air gap extending transversely to the thickness direction 4 remains. Here, too, the dielectric coating 12 or the material layer 17 laterally encloses the contact plates 3a and 3b in order to enlarge an air gap 22 in the edge region 15 of the contact plates 3a and 3b. Here, no dielectric coating 12 is applied onto the end faces 14a and 14b.

(10) FIG. 5 shows a sectional view of the PTC heating module 1 from FIG. 1 without the housing 8 and without the rib structure 9.

(11) FIG. 6 shows a sectional view of the alternatively configured PTC heating module 1 with the function element 11 in the form of the dielectric coating 12. In this exemplary embodiment, the dielectric coating 12, deviating from FIG. 3, is also applied onto the end faces 14a and 14b of the contact plates 3a and 3b. Here, a basic coating and an insulation cladding can be omitted. Otherwise, the PTC heating module 1, in this case, corresponds to the PTC heating module in FIG. 3.

(12) FIG. 7 shows a sectional view of the alternatively configured PTC heating module 1 with the function element 11 in the form of an insulation plate 18. The insulation plate 18 is preferentially produced from ceramic and is arranged between the two contact plates 3a and 3b, so that the hollow space 10 between the contact plates 3a and 3b round about the respective PTC thermistors 2 is completely filled out. Furthermore, the insulation plate 18 projects transversely to the thickness direction 4 out of the hollow space 10 towards the outside, so that in the edge region 15 of the contact plates 3a and 3b an air gap is enlarged.

(13) FIG. 8 shows a sectional view of the alternatively configured PTC heating module 1 with the function element 11 in the form of the dielectric coating 12. In this exemplary embodiment, a basic coating 16 or an insulation cladding 20 is applied onto the end faces 14a and 14b of the contact plates 3a and 3b, which are not distinguishable in the sectional view shown here. Otherwise, the PTC heating module 1, in this case, corresponds to the PTC heating module in FIG. 2.

(14) FIG. 9 shows a sectional view of the alternatively configured PTC heating module 1 with the function element 11 in the form of the dielectric coating 12. Deviating from FIG. 3, the dielectric coating 12 in this case does not engage about the contact plates 3a and 3b. Instead, the dielectric coating 12 projects out of the hollow space 12 transversely to the thickness direction 4 so that an air gap in the edge region 15 of the contact plates 3a and 3b is enlarged. Otherwise, the PTC heating module 1, in this case, corresponds to the PTC heating module in FIG. 3.

(15) FIG. 10 shows a sectional view of the alternatively configured PTC heating module 1 with the function element 11 in the form of the dielectric coating 12. Deviating from the embodiment in FIG. 2, the respective PTC thermistor 2, in this case, is electrically contacted with the respective contact plate 3a and 3b in each case via a contact base 19a and 19b. A support face 21a and 21b of the respective contact base 19a and 19b is smaller than the respective main surface 5a and 5b of the PTC thermistor 2, so that the respective PTC thermistor 2 projects on the respective contact base 19a and 19b transversely to the thickness direction 4. Furthermore, the thickness of the respective contact base 19a and 19b is smaller in the thickness direction 4 than the layer thickness of the material part layers 13a and 13b, so that the contact base 19a and 19b is completely clad laterally by the dielectric coating 12.

(16) FIG. 11 shows a sectional view of the alternatively configured PTC heating module 1 with the function element 11 in the form of the dielectric coating 12. Deviating from the embodiment in FIG. 3, the respective PTC thermistor 2 in this case is electrically contacted with the respective contact plate 3a and 3b via the contact base 19a and 19b. Here, the dielectric coating 12 is formed by the two material part layers 13a and 13b, wherein the respective material part layers 13a and 13b completely clad the respective contact bases 19a and 19b laterally. Otherwise, the PTC module 1, in this case, corresponds to the PTC heating module in FIG. 3.

(17) FIG. 12 shows a sectional view of the alternatively configured PTC heating module 1 with the function element 11 in the form of the dielectric coating 12. Here, the respective PTC thermistors 2 are also electrically contacted with the contact plates 3a and 3b by the contact bases 19a and 19b. Otherwise the PTC heating module 1, in this case, corresponds to the PTC heating module in FIG. 2.

(18) The dielectric coating 12 in FIGS. 1-6 and FIGS. 8-12 can be applied by injecting or by over-moulding or by spraying-on a dielectric material or by anodizing with a dielectric material or by dipping into a dielectric material or by gluing a film of a dielectric material or by a further suitable method to the contact surface 6a and 6b of the respective contact plate 3a and 3b. It goes without saying that the application method should be selected dependent on the desired embodiment of the dielectric coating 12. The dielectric material is preferentially plastic. The basic coating and the insulation cladding are formed from an electrical and preferentially heat-conductive material. The respective contact plates 3a and 3b and the housing 8 and the rib structure 9 can consist for example of metal. The respective PTC thermistors are produced from a PTC thermistor material. The insulation plate 18 in FIG. 6 can consist for example of ceramic.

(19) In summary, the two potential-carrying contact plates 3a and 3b in the PTC heating module 1 are physically separated from one another by the function element 11. Because of this, a creepage distance between the two contact plates 3a and 3b is enlarged and the creepage currents in the PTC heating module 1 excluded. Altogether, the voltage in the PTC heating module 1 and because of this its output can be increased without adjusting the dimensions of the PTC thermistors 2 in the thickness direction 4.