PTC HEATING MODULE

Abstract

A PTC heating module for heating a fluid may include at least one PTC thermistor having two flat main surfaces disposed opposite one another. The two main surfaces may be arranged parallel to and spaced apart from one another defining a thermistor thickness of the at least one PTC thermistor therebetween. The two main surfaces may be connected to one another by at least one lateral surface and the at least one PTC thermistor may be delimited toward an outside by the at least one lateral surface and the two main surfaces. The module may also include two contact plates between which the at least one PTC thermistor is arranged. A cross section of the at least one PTC thermistor defined perpendicularly to the two main surfaces may deviate from a rectangle such that a creep distance between the two main surfaces is greater than the thermistor thickness.

Claims

1. A PTC heating module for heating a fluid, comprising: at least one PTC thermistor having two flat main surfaces disposed opposite one another; the two main surfaces arranged parallel to and spaced apart from one another defining a thermistor thickness of the at least one PTC thermistor therebetween; the two main surfaces connected to one another by at least one lateral surface and the at least one PTC thermistor delimited toward an outside by the at least one lateral surface and the two main surfaces; two contact plates between which the at least one PTC thermistor is arranged wherein a cross section of the at least one PTC thermistor defined perpendicularly to the two main surfaces deviates from a rectangle such that a creep distance between the two main surfaces is greater than the thermistor thickness.

2. The PTC heating module according to claim 1, wherein the at least one lateral surface has a cutting angle relative to a respective main surface of the two main surfaces that deviates from 90 such that the cross section of the at least one PTC thermistor corresponds to a non-rectangular trapezium.

3. The PTC heating module according to claim 1, wherein the at least one lateral surface is defined by a plurality of surfaces each arranged relative to one another at a cutting angle that deviates from zero such that the cross section of the at least one PTC thermistor corresponds to one of a concave polygon and a convex polygon with more than four corners.

4. The PTC heating module according to claim 1, wherein the at least one lateral surface includes at least one step-like moulding.

5. The PTC heating module according to claim 1, wherein the at least one PTC thermistor is at least one of provided as a single piece and monolithical.

6. The PTC heating module according to claim 1, wherein the at least one PTC thermistor is defined by a plurality of PTC elements stacked against one another with a stacking surface.

7. The PTC heating module according to claim 6, further comprising, disposed between each of the plurality of PTC elements stacked against one another, an electrically and thermally conductive coating, wherein the coating at least partially covers the stacking surface of each of the plurality of PTC elements.

8. The PTC heating module according to claim 1, wherein: in that each of the two main surfaces have a contacting layer extending over an entire surface; and each of the two contact plates lies against the contacting layer of one of the two main surfaces with an entire surface.

9. The PTC heating module according to claim 1, wherein a surface of the at least one PTC thermistor through which electric current flows changes from one of the two contact plates to the other of the two contact plates.

10. The PTC heating module according to claim 1, wherein, in the at least one PTC thermistor, a current flow direction between the two contact plates substantially corresponds to a heat flow direction between the two main surfaces.

11. The PTC heating module according to claim 1, wherein the at least one PTC thermistor includes a plurality of PTC thermistors arranged next to one another between the two contact plates.

12. The PTC heating module according to claim 1, wherein the at least one lateral surface is defined by a plurality of surfaces extending transversely to one another and the two main surfaces such that the cross section of the at least one PTC thermistor is shaped as a concave polygon having more than four corners.

13. The PTC heating module according to claim 1, wherein the at least one lateral surface is defined by a plurality of surfaces extending transversely to one another and the two main surfaces such that the cross section of the at least one PTC thermistor is shaped as a convex polygon with more than four corners.

14. A PTC heating module for heating a fluid, comprising: a plurality of PTC thermistors each having and delimited by two flat main surfaces connected by at least one lateral surface, the two flat main surfaces extending parallel to one another and disposed opposite one another defining a thermistor thickness therebetween; two contact plates between which the plurality of PTC thermistors are arranged next to one another; a contacting layer of a plurality of contacting layers extending along an entirety of each of the two main surfaces of each of the plurality of PTC thermistors, the two contacting plates lying against the plurality of contacting layers; wherein each of the plurality of PTC thermistors has a cross section defined perpendicularly to the two main surfaces which deviates from a rectangular shape such that a creep distance between the two main surfaces is greater than the thermistor thickness.

15. The PTC heating module according to claim 14, wherein a current flow direction between the two contact plates substantially corresponds to a heat flow direction between the two main surfaces of each of the plurality of PTC thermistors.

16. A PTC heating module for heating a fluid, comprising: a plurality of PTC thermistors each having and delimited by two flat main surfaces connected by a plurality of lateral surfaces, the two flat main surfaces extending parallel to one another and disposed opposite one another defining a thermistor thickness therebetween; each of the plurality of PTC thermistors defined by a plurality of PTC elements each having at least one stacking surface, the plurality of PTC elements stacked on top of one another via the at least one stacking surface; two contact plates between which the plurality of PTC thermistors are arranged next to one another; wherein a cross section of each of the plurality of PTC thermistors defined perpendicularly to the two main surfaces deviates from a rectangular shape such that a creep distance between the two main surfaces is greater than the thermistor thickness.

17. The PTC heating module according to claim 16, wherein the plurality of lateral surfaces extend transversely to each of the two main surfaces at a non-right angle.

18. The PTC heating module according to claim 17, wherein the two main surfaces are connected by at least two adjacent lateral surfaces of the plurality of lateral surfaces adjoining one another between the two main surfaces, the at least two adjacent lateral surfaces extending transversely to one another by a cutting angle such that the cross section of the at least one PTC thermistor is shaped as one of a concave polygon with more than four corners and a convex polygon with more than four corners.

19. The PTC heating module according to claim 16, wherein an electrically and thermally conductive coating is disposed on and covers an entirety of the at least one stacking surface of each of the plurality of PTC elements.

20. The PTC heating module according to claim 16, wherein at least one of the plurality of lateral surfaces includes at least one step-like moulding.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] It shows, in each case schematically

[0023] FIG. 1 a sectional view of a PTC heating module according to the invention;

[0024] FIG. 2 an exploded view of contact plates and of PTC thermistors arranged between the contact plates in the PTC heating module from FIG. 1;

[0025] FIGS. 3 to 20 views of differently configured PTC thermistors in the PTC heating module according to the invention.

DETAILED DESCRIPTION

[0026] 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 each with two flat main surfaces 3a and 3b located opposite one another. The two main surfaces 3a and 3b are arranged parallel to and spaced from one another and define a thermistor thickness D.sub.PTC of the respective PTC thermistor 2. The main surfaces 3a and 3b of the respective PTC thermistor 2 are, furthermore, connected to one another by lateral surfaces 4 and the PTC thermistor 2 is delimited to the outside by the lateral surfaces 4 and the main surfaces 3a and 3b. The PTC heating module 1, furthermore, comprises two contact plates 5a and 5b between which the respective PTC thermistor 2 is arranged. Between the respective contact plate 5a and 5b and the respective main surface 3a and 3b of the respective PTC thermistor 2, an electrically and thermally conductive contacting layer 6a and 6b is arranged in each case. In FIG. 2, an exploded view of the contact plates 5a and 5b and the multiple PTC thermistors 2 in the PTC heating module 1 is shown.

[0027] The respective PTC thermistors 2 are arranged next to one another between the two contact plates 5a and 5b and contacted to these in an electrically and thermally conductive manner via the respective contacting layers 6a and 6b. In the respective PTC thermistor 2, a current flow direction between the two contact plates 5a and 5b with the applied voltage substantially corresponds to a heat flow direction between the two main surfaces 3a and 3b. The contact plates 5a and 5b with the respective PTC thermistor 2 are arranged in a housing 7, wherein the contact plates 5a and 5b are separated from the housing 7 in each case by an electrically insulating and thermally conductive insulating layer 8a and 8b. On the one hand, the heat generated in the respective PTC thermistor 2 can be discharged via the contact plates 5a and 5b and via the insulating layers 8a and 8b to the housing 7 and further to the outside and on the other hand the housing 7 can be electrically insulated toward the outside. Furthermore, a rib structure 9 is fixed to the housing 7 in a thermally conductive manner which is provided for the effective dissipation of the heat from the housing 7 to the fluid circulating about the rib structure 9.

[0028] The PTC thermistor 2 has a cross section that deviates from a rectangle. Because of this, a creep distance 10 between the two main surfaces 3a and 3b is greater than the thermistor thickness D.sub.PTC of the PTC thermistor 2. The creep distance 10 in this case is defined by the shortest distance of the main surfaces 3a and 3b of the PTC thermistor 2 along the respective lateral surface 4 of the PTC thermistor 2. Through the geometry of the PTC thermistor 2, the thermistor thickness D.sub.PTC is independent of the creep distance 10 demanded for the specified voltage so that the output of the PTC heating module 1 is optimisable independently of the thermistor thickness D.sub.PTC.

[0029] Views of the differently configured PTC thermistor 2 are shown in FIG. 3 to FIG. 20. Independently of their configuration, the shown PTC thermistors 2 are constructed of multiple PTC elements 15a and 15b each of which have a stacking surface 16. Between the respective PTC elements 15a and 15b that are stacked against one another, an electrically and thermally conductive coating 17 each is arranged, wherein the coating 17 in its dimensions corresponds to the smallest stacking surface 16 of the two PTC elements 15a and 15b lying against one another. In particular in the PTC thermistors 2 according to FIG. 15 to FIG. 20, a shortening of the creep distance 10 can thereby be prevented. The respective main surfaces 3a and 3b of the shown PTC thermistors 2 are coated over the entire surface with the respective contacting layers 9a and 9b. Alternatively to the examples shown here, the PTC thermistors 2 in FIG. 3 to FIG. 20 can also be in one piece or monolithical regardless of their configuration. Deviating from the shown examples, the respective PTC elements 15a and 15b, furthermore, can also be stacked against one another without a coating 17.

[0030] In FIG. 3 to FIG. 5, views of the PTC thermistor 2 are shown which is designed rotation-symmetrically. The respective lateral surface 4 in this case is formed from two flat part surfaces 13a and 13b which are each arranged at a cutting angle a relative to one another that deviates from zero. The cross section of the PTC thermistor 2 in this case corresponds to a convex hexagon.

[0031] In FIG. 6 to FIG. 8, views of the PTC thermistor 2 are shown which has square main surfaces 3a and 3b. The respective lateral surfaces 4 in this case are each formed from two flat part surfaces 13a and 13b which are each relative to one another at a cutting angle deviating from zero. The cross section of the PTC thermistor 2 in this case corresponds to a convex hexagon.

[0032] In FIG. 9 to FIG. 11, views of the PTC thermistor 2 are shown which is designed rotation-symmetrical. The respective lateral surface 4 in this case is formed from two flat part surfaces 13a and 13b each of which are arranged relative to one another at a cutting angle a deviating from zero. The cross section of the PTC thermistor 2 in this case corresponds to a concave hexagon.

[0033] In FIG. 12 to FIG. 14, views of the PTC thermistor 2 are shown which has rectangular main surfaces 3a and 3b. The respective lateral surfaces 4 in this case are each formed from two flat part surfaces 13a and 13b which are arranged relative to one another at a cutting angle a deviating from zero. The cross section of the PTC thermistor 2 in this case corresponds to a concave hexagon.

[0034] In FIG. 15 to FIG. 17, views of the PTC thermistor 2 are shown which has square main surfaces 3a and 3b. The respective lateral surfaces 4 in this case each have a stepped moulding 14. The cross section of the PTC thermistor 2 in this case corresponds to a convex octagon.

[0035] In FIG. 18 to FIG. 20, views of the PTC thermistor 2 are shown which has square main surfaces 3a and 3b and a step-like moulding 14 arranged in the middle. The cross section of the PTC thermistor 2 in this case corresponds to a convex dodecagon.

[0036] In summary, the creep distance 10 in the PTC heating module 1 between the two main surfaces 3a and 3b is adaptable by the cross section of the PTC thermistor 2 independently of the thermistor thickness D.sub.PTC. The air gap 10b between the contact plates 5a and 5b can also be adapted independently of the thermistor thickness D.sub.PTC. The thermistor thickness D.sub.PTC of the respective PTC thermistor 2 is thereby independent of the specified voltage so that the output of the PTC heating module 1 can be optimised through the adapted thermistor thickness D.sub.PTC.