POSITIVE TEMPERATURE COEFFICIENT (PTC) HEATER

Abstract

A positive temperature coefficient (PTC) heater may include a housing and at least one PTC heating element arranged within the housing. The at least one PTC heating element may include a heating layer of a PTC material arranged between two electrode plates of the at least one PTC heating element and electrically contacted therewith. The two electrode plates may be fixed to the housing such that heat is transferable and and the two electrode plates are electrically insulated from the housing. At least one electrically insulated heat conducting layer may be arranged to divide the heating layer into a divided heating layer and may be fixed to the divided heating layer to transfer heat.

Claims

1. A positive temperature coefficient (PTC) heater comprising: at least one PTC heating element including a heating layer of a PTC material arranged between two electrode plates of the at least one PTC heating element and electrically contacted therewith; and a housing, in which the at least one PTC heating element is arranged; wherein the two electrode plates are fixed to the housing such that heat is transferable and the two electrode plates are electrically insulated from the housing; and wherein at least one electrically insulated heat conducting layer is arranged to divide the heating layer into a divided heating layer and is fixed to the divided heating layer to transfer heat.

2. The PTC heater according to claim 1, wherein the at least one heat conducting layer extends from one of the two electrode plates to the other of the two electrode plates and divides the heating layer in a direction extending between the two electrode plates.

3. The PTC heater according to claim 1, wherein the at least one heat conducting layer extends parallel to the two electrode plates and divides the heating layer in a direction parallel to the two electrode plates.

4. The PTC heater according to claim 3, wherein a heat distribution body of the at least one PTC heating element is fixed to the at least one heat conducting layer on one side and to the housing on another side facilitating a transfer of heat therebetween.

5. The PTC heater according to claim 4, wherein the heat distribution body is composed of a sintered ceramic.

6. The PTC heater according to claim 1, wherein at least one of: the at least one heat conducting layer is composed of a sintered ceramic; and the heating layer is composed of a sintered PTC material.

7. The PTC heater according to claim 1, wherein the at least one heat conducting layer is a metal plate, which is electrically insulated from the divided heating layer via an insulating coating.

8. The PTC heater according to claim 1, further comprising two electrically insulating insulating plates each coupling a respective electrode plate of the two electrode plates to the housing to transfer heat, wherein each of the two insulating plates is arranged between the respective electrode plates and the housing.

9. The PTC heater according to claim 8, wherein at least one of the two insulating plates is connected to a heat distribution body of the at least one PTC heating element to transfer heat.

10. The PTC heater according to claim 8, wherein the two insulating plates are composed of at least one of an aluminum oxide, a sintered ceramic, an aluminum nitride, and a boron nitride.

11. The PTC heater according to claim 1, wherein the at least one heat conducting layer is composed of a sintered ceramic including at least one of aluminum nitride and boron nitride.

12. The PTC heater according to claim 1, wherein the heating layer is composed of a sintered PTC material including barium titanate.

13. The PTC heat according to claim 5, wherein the sintered ceramic includes at least one of aluminum nitride and boron nitride.

14. The PTC heater according to claim 7, wherein the insulating coating is one of an oxide layer, a varnish, and an insulating film.

15. A positive temperature coefficient (PTC) heater comprising a housing and at least one PTC heating element arranged within the housing, the at least one PTC heating element including: two electrode plates configured to be coupled to the housing such that heat is transferable therebetween and the two electrode plates are electrically insulated from the housing; a plurality of heating layers of a PTC material arranged between and electrically contacting the two electrode plates; and at least one electrically insulated heat conducting layer alternating arranged with the plurality of heating layers, the at least one heat conducting layer coupled to the plurality of heating layers in a heat transferring manner.

16. The PTC heater according to claim 15, wherein the at least one heat conducting layer and the plurality of heating layers extend between the two electrode plates.

17. The PTC heater according to claim 15, wherein the at least one heat conducting layer and the plurality of heating layers extend parallel to the two electrode plates.

18. The PTC heater according to claim 15, wherein the at least one heat conducting layer includes an insulating coating electrically insulating the at least one heat conducting layer from the plurality of heating layers.

19. A positive temperature coefficient (PTC) heater comprising a housing and at least one PTC heating element arranged within the housing, the at least one PTC heating element including: two electrode plates; two electrically insulating insulating plates configured to be arranged between the two electrode plates and the housing, each of the two insulating plates configured to be a respective electrode plate of the two electrode plates to the housing such that heat is transferable therebetween and the two electrode plates are electrically insulated from the housing; a plurality of heating layers of a PTC material arranged between and electrically contacting the two electrode plates; and at least one electrically insulated heat conducting layer alternating arranged with the plurality of heating layers, the at least one heat conducting layer coupled to the plurality of heating layers in a heat transferring manner.

20. The PTC heater according to claim 19, wherein the at least one PTC heating element further includes a heat distribution body coupled to the at least one heat conducting layer on one side and configured to be coupled to the housing on another side facilitating a transfer of heat therebetween.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In each case schematically

[0019] FIGS. 1 and 2 show sectional views of a PTC heater according to the invention;

[0020] FIG. 3 shows a view of a PTC heater according to the invention according to FIG. 1 and FIG. 2;

[0021] FIGS. 4 and 5 show sectional views of a PTC heater according to the invention in an alternative embodiment;

[0022] FIG. 6 shows views of PTC heater according to the invention according to FIG. 4 and FIG. 5 comprising a heat distribution body.

DETAILED DESCRIPTION

[0023] FIG. 1 and FIG. 2 show sectional views of a PTC heater 1 according to the invention. FIG. 3 shows a perspective view of the PTC heater 1. The PTC heater 1 thereby has a PTC heating element 2 comprising a heating layer 3, which is arranged between two electrode plates 4a and 4b and which is electrically contacted therewith. The heating layer 3 is made of a PTC material, which preferably has barium titanate or consists thereof. The PTC heating element 2 is encapsulated in a housing 5 of the PTC heater 1 in a dust-tight and water-tight manner, wherein insulating plates 6a and 6b are arranged between the electrode plates 4a and 4b and the housing 5. The respective insulating plates 6a and 6b are fixed to the housing 5 so as to transfer heat and electrically insulate the electrode plates 4a and 4b from the housing 5. The PTC heater 1 is protected against touch and flashover in this way. The insulating plates 6a and 6b can consist for example of an aluminum oxide. The heat generated in the heating layer 3 is released to heating surfaces 7a and 7b of the housing 5 via the electrode plates 4a and 4b as well as the insulating plates 6a and 6b.

[0024] In FIG. 1 and FIG. 2, two heat conducting layers 8 divide the heating layer 3 vertically to the electrode plates 4a and 4b and abut on both sides of the heating layer 3 so as to transfer heat. As shown in FIG. 1, the respective heat conducting layer 8 can consist for example of a sintered ceramic, which is preferably an aluminum nitride or a boron nitride. In the case of the sintered aluminum nitride, the heat conducting layer 8 then has a heat conductivity of approximately 130 W/mK and a heat conductivity of approximately 60 W/mk in the case of the sintered boron nitride. In contrast, the heating layer 3 of the sintered barium titanate has a heat conductivity of approximately 2 W/mK. The heat conducting layer 8 can effectively dissipate the heat generated in the heating layer 3 to the electrode plates 4a and 4b and can prevent an unwanted throttling of the PTC heating element 2 and of the PTC heater 1 thereby. The respectively heat conducting layer 8 of aluminum nitride or boron nitride is also electrically insulating, so that electrical properties of the PTC heating element 2 are not influenced by the heat conducting layers 8. As an alternative to FIG. 1, the respective heat conducting layer 8 in FIG. 2 is a metal plate 9, which is electrically insulated from the divided heating layer 3 and the electrode plates 4a and 4b by means of an insulating coating 10. The insulating coating 10 can for example be an oxide layer or a varnish or an insulating film. Here, the respective heat conducting layers 8 also have a higher heat conductivity than the heating layer 3.

[0025] As shown in FIG. 3, a voltage is applied to the electrode plates 4a and 4b and the wattage is converted into the heat in the heating layer 3. When the temperature rises, the resistance of the heating layer 3 rises as well and the PTC heating element 2 throttles to a constant temperature by means of its own behavior. The respective heat conducting layers 8 have a higher heat conductivity than the heating layer 3 and dissipate the heat generated in the heating layer 3 to the electrode plates 4a and 4b and to the housing 5 via the insulating plates 6a and 6b. The heating surfaces 7a and 7b then release the heat to the surrounding area. As a whole, the heat generated in the heating layer 3 in this way can be dissipated evenly from the PTC heating element 2 in this way and an unwanted throttling of the PTC heating element 2 and of the PTC heater 1 can be prevented in an advantageous manner thereby. The respective heat conducting layer 8 is thereby electrically insulated from the divided heating layer 3 and the electrode plates 4a and 4b, so that electrical properties of the PTC heating element 2 and of the PTC heater 1 are not influenced.

[0026] FIG. 4 and FIG. 5 show sectional views of the PTC heater 1 according to the invention in an alternative embodiment. The heat conducting layer 8 extends in parallel to the electrode plates 4a and 4b and divides the heating layer 3 parallel to the electrode plates 4a and 4b. The heat conducting layer 8 can dissipate the heat from a middle area 11 of the heating layer 3 in a particularly effective manner in this way. In FIG. 4, the heat conducting layer 8 consists of a sintered ceramic, which preferably has aluminum nitride or boron nitride, or consists thereof. In FIG. 5, the heat conducting layer 8 is the metal plate 9 comprising the insulating coating 10. The insulating coating 10 can for example be an oxide layer or a varnish or an insulating film. In both cases, the heat conducting layer 8 has a higher heat conductivity than the heating layer 3 and can effectively dissipate the heat from the middle area 11 of the heating layer 3.

[0027] In FIG. 6, the heat conducting layer 8 is further connected to the housing 5 via a heat distribution body 12 of the PTC heating element 2 so as to transfer heat. The heat distribution body 12 can consist for example of a sintered ceramic, which is preferably an aluminum nitride or a boron nitride. The heat distribution body 12 dissipates the heat, which is released into the surrounding area at body heating surfaces 13a and 13b from the heat conducting layer 8 to the housing 5. The body heating surface 13a and 13b connect to the heating surfaces 7a and 7b of the PTC heater 1 and the heat generated in the PTC heating element 2 can be released into the surrounding area in a large-scale and effective manner.

[0028] As a whole, the heat generated in the PTC heater 1 according to the invention in the heating layer 3 can be effectively dissipated to the outside and an unwanted throttling of the PTC heating element 2 can be prevented in an advantageous manner thereby. Furthermore, the heat output of the PTC heating element 2 and of the PTC heater 1 is increased thereby.