Heating element

Abstract

Provided is a heating element which has a good heating property, and the shape of which can be easily adjusted. The heating element according to an embodiment of the present invention comprises a plurality of honeycomb structure units each having a honeycomb structure which generates heat through energization and has a partition wall defining a plurality of cells that extend from a first end surface to a second end surface and serve as a flow path of fluid. The plurality of honeycomb structure units include a first honeycomb structure unit and a second honeycomb structure unit. The fluid that has passed through the first honeycomb structure unit passes through an insulation part formed between the first honeycomb structure unit and the second honeycomb structure unit, and passes through the second honeycomb structure unit.

Description

heating element

[0001] The present invention relates to a heating element.

[0002] It has been proposed to generate heat by passing electricity through a honeycomb structure used as a catalyst carrier or the like. For example, as disclosed in Patent Document 1, when treating harmful substances in exhaust gas emitted from a vehicle engine, if the catalyst temperature is low, the catalyst does not heat up to a predetermined temperature, and the exhaust gas is not sufficiently purified. To solve this problem, a honeycomb structure that can be used as a catalyst carrier and also function as a heating element has been proposed.

[0003] Patent No. 6438939

[0004] However, there are cases where the use of a heating element is desired for applications other than exhaust gas purification from internal combustion engines. For example, it is desirable to be able to easily adjust the shape of the heating element depending on the application.

[0005] In view of the above, the present invention provides a heating element that has excellent heat generating properties and whose shape can be easily adjusted.

[0006] 1. A heating element according to an embodiment of the present invention is a heating element including a plurality of honeycomb structure units having a honeycomb structure portion that generates heat when electrically connected, the honeycomb structure portion having partition walls that extend from a first end face to a second end face and define a plurality of cells that serve as fluid flow paths, the plurality of honeycomb structure units including a first honeycomb structure unit and a second honeycomb structure unit, and a fluid that has passed through the first honeycomb structure unit passes through an insulating portion formed between the first honeycomb structure unit and the second honeycomb structure unit, and then passes through the second honeycomb structure unit. 2. In the heating element described in 1 above, the plurality of honeycomb structure units may each have a pair of electrode portions that electrically heat the honeycomb structure portion. 3. In the heating element described in 2 above, the honeycomb structure portion may have an outer peripheral wall that surrounds the partition walls. The pair of electrode portions may be provided on the outer peripheral wall, and when the honeycomb structure portion is viewed from the cell extension direction, the pair of electrode portions may be arranged on one side of the center of the honeycomb structure portion. 4. In the heating element described in any one of items 1 to 3 above, the extension direction of the cells of the first honeycomb structure unit may be aligned with the extension direction of the cells of the second honeycomb structure unit. 5. In the heating element described in any one of items 1 to 4 above, the insulating portion may include an insulating member made of an insulating material. 6. In the heating element described in item 5 above, the insulating member may be arranged in contact with the first honeycomb structure unit and the second honeycomb structure unit. 7. In the heating element described in item 5 or 6 above, the insulating member may be bonded to the first honeycomb structure unit and the second honeycomb structure unit. 8. In the heating element described in any one of items 5 to 7 above, the insulating member may have partition walls that define a plurality of cells that serve as fluid flow paths. 9. In the heating element described in 8 above, an aperture ratio per unit area of ​​a face of the honeycomb structure portion perpendicular to the cell extension direction may be smaller than an aperture ratio per unit area of ​​a face of the insulating member perpendicular to the cell extension direction.10. In the heating element described in 8 or 9 above, the hydraulic diameter of the cells of the honeycomb structure portion may be smaller than the hydraulic diameter of the cells of the insulating member. 11. In the heating element described in any one of 5 to 10 above, when the first honeycomb structure unit is viewed from the cell extension direction, a region may be formed in which the honeycomb structure portion of the first honeycomb structure unit and the insulating member do not overlap. 12. In the heating element described in 11 above, when the first honeycomb structure unit is viewed from the cell extension direction, a region in which the insulating member is not present may be formed in the center of the honeycomb structure portion of the first honeycomb structure unit. 13. In the heating element described in any one of 5 to 12 above, the insulating member may be made of ceramics. 14. In the heating element described in any one of 5 to 13 above, the insulating member may contain a catalyst. 15. In the heating element described in any one of 1 to 14 above, the honeycomb structure portion may be made of ceramics. 16. 16. In the heating element according to any one of 1 to 15 above, the honeycomb structure portion may contain a catalyst.

[0007] According to an embodiment of the present invention, a heating element having excellent heat generating properties and whose shape can be easily adjusted can be provided.

[0008] Fig. 1 is a schematic diagram of the general configuration of a heating element according to a first embodiment of the present invention when viewed from above. Fig. 2 is a perspective view showing the general configuration of a first honeycomb structure unit constituting the heating element shown in Fig. 1. Fig. 3 is a diagram showing an example of a cross section taken along III-III in Fig. 1. Fig. 4 is a diagram showing an example of a cross section of the heating element shown in Fig. 1. Fig. 5 is a cross-sectional view showing the general configuration of a modified honeycomb structure unit. Fig. 6 is a cross-sectional view showing the general configuration of a heating element according to a second embodiment of the present invention.

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. In order to clarify the description, the drawings may schematically show the width, thickness, shape, etc. of each part compared to the embodiments, but these are merely examples and do not limit the interpretation of the present invention. Furthermore, in the drawings, the same or equivalent elements are given the same reference numerals, and redundant explanations may be omitted.

[0010] A heating element according to an embodiment of the present invention includes a plurality of honeycomb structure units. Fig. 1 is a schematic diagram of the general configuration of a heating element according to a first embodiment of the present invention when viewed from above, Fig. 2 is a perspective view showing the general configuration of a first honeycomb structure unit constituting the heating element shown in Fig. 1, Fig. 3 is a diagram showing an example of a cross section taken along line III-III in Fig. 1, and Fig. 4 is a diagram showing an example of a cross section of the heating element shown in Fig. 1.

[0011] The heating element 100 includes a first honeycomb structure unit 1 and a second honeycomb structure unit 2. The first honeycomb structure unit 1 and the second honeycomb structure unit 2 each include a honeycomb structure portion 10 that can generate heat when an electric current is applied thereto and a pair of electrode portions 20, 20 that heat the honeycomb structure portion 10 by applying an electric current thereto.

[0012] As shown in Fig. 2, the first honeycomb structure unit 1 has a honeycomb structure portion 10 and a pair of electrode portions 20, 20. The honeycomb structure portion 10 has partition walls 14 that extend (in the length direction) from a first end face 10a to a second end face 10b and define a plurality of cells 12 that can serve as fluid flow paths, and an outer peripheral wall 16 that is located on the periphery and surrounds the partition walls 14. Note that Fig. 2 shows the first honeycomb structure unit 1 shown in Fig. 1 as a representative, but the second honeycomb structure unit 2 also has a similar configuration.

[0013] As shown in Fig. 4, in the heating element 100, the first honeycomb structure unit 1 and the second honeycomb structure unit 2 are arranged so that the extension direction (length direction) of the cells 12 of each honeycomb structure unit 10 is aligned. The arrows in Fig. 1 indicate the fluid flow direction. The fluid that has passed through the first honeycomb structure unit 1 can pass through the second honeycomb structure unit 2. In the heating element 100, the first honeycomb structure unit 1 and the second honeycomb structure unit 2 are arranged apart from each other. The heating element 100 includes an insulating section 30 formed between the first honeycomb structure unit 1 and the second honeycomb structure unit 2. The fluid that has passed through the first honeycomb structure unit 1 passes through the insulating section 30 formed between the first honeycomb structure unit 1 and the second honeycomb structure unit 2, and then passes through the second honeycomb structure unit 2.

[0014] In the illustrated example, the heating element includes two honeycomb structure units, but may include three or more honeycomb structure units. For example, an insulating section 30 may be provided in advance on the end face of the second honeycomb structure unit 2 on the side where the first honeycomb structure unit 1 is not arranged, and another honeycomb structure unit may be provided via this insulating section 30. Three or more honeycomb structure units may be arranged with the extension directions of their respective cells aligned. Three or more honeycomb structure units may be arranged spaced apart from each other.

[0015] By arranging multiple honeycomb structure units that can generate heat by passing electricity through insulating parts, the heating element can have extremely excellent heat generation characteristics. Specifically, the energy applied to each honeycomb structure unit can be efficiently used to raise the temperature of the honeycomb structure unit that serves as the fluid flow path. Although a temperature difference usually occurs between the upstream and downstream sides of the honeycomb structure unit in the fluid flow direction (e.g., the downstream side may be higher in temperature than the upstream side), each honeycomb structure unit can effectively control the temperature of the fluid flow path. Furthermore, short circuits between honeycomb structure units can be prevented, preventing problems such as damage to the device or circuit that supplies power to the heating element. Furthermore, by arranging multiple honeycomb structure units through insulating parts, the shape of the resulting heating element can be adjusted depending on the application.

[0016] The outer peripheral wall 16 of the honeycomb structure section 10 extends in the length direction. Each of the plurality of cells 12 is a space extending in the length direction. The cross-sectional shape of each cell 12 perpendicular to the length direction is quadrangular in the illustrated example, but may be other polygonal shapes or other shapes such as circular. The thickness of the partition walls 14 is, for example, 70 μm to 500 μm. The number of cells 12 per unit area in a plane perpendicular to the extension direction of the cells 12 is, for example, 15 cells / cm. ２ ~150 cells / cm ２ The thickness of the partition walls 14 and the number of the cells 12 can be measured using, for example, a digital microscope.

[0017] The aperture ratio of the honeycomb structure 10 is, for example, 65% to 90%. Here, the aperture ratio of the honeycomb structure 10 refers to the aperture ratio per unit area in a plane perpendicular to the extension direction of the cells 12 of the honeycomb structure 10. Specifically, the aperture ratio of the honeycomb structure 10 is the ratio of the total area of ​​the void portions of the cells 12 to the total area of ​​the plane perpendicular to the extension direction of the cells 12 of the honeycomb structure 10. The aperture ratio of the honeycomb structure 10 can be measured, for example, using a digital microscope.

[0018] The hydraulic diameter of the cells 12 of the honeycomb structure section 10 is, for example, 0.7 mm to 1.8 mm. Here, the hydraulic diameter of the cells 12 of the honeycomb structure section 10 is determined by the ratio of the perimeter (unit: mm) surrounded by the partition walls 14 to the cross-sectional area of ​​the cells 12 (unit: mm ２ ) and is calculated by the formula: 4 × (cross-sectional area) / (perimeter). The perimeter surrounded by the partition walls 14 and the cross-sectional area of ​​the cell 12 can be measured using, for example, a digital microscope.

[0019] In the illustrated example, the cross-sectional shape of the outer peripheral wall 16 perpendicular to the longitudinal direction is rectangular, but it may be another polygon, or may be another shape such as circular. The thickness of the outer peripheral wall 16 is, for example, 0.5 mm to 5 mm. In the example shown in FIG. 1, the honeycomb structure parts of the two honeycomb structure units constituting the heating element have the same shape and size, but the heating element may also be composed of multiple honeycomb structure unit parts having different shapes and sizes. The thickness of the outer peripheral wall 16 can be measured, for example, using a digital microscope.

[0020] A pair of electrode portions 20, 20 are provided on the outer peripheral wall 16 of the honeycomb structure portion 10. Each of the pair of electrode portions 20, 20 may be configured with an electrode terminal, one electrode terminal being connected to the positive pole of a power source and the other electrode terminal being connected to the negative pole of the power source. When the honeycomb structure portion 10 is viewed from the direction in which the cells 12 extend, the pair of electrode portions 20, 20 are arranged on one side of the center of the honeycomb structure portion 10. This arrangement can significantly improve the ease of assembling the heating element. It can also contribute to space savings when installing the heating element. Note that the arrangement of the pair of electrode portions 20, 20 is not particularly limited as long as the honeycomb structure portion 10 can be electrically heated. For example, the pair of electrode portions 20, 20 may be arranged on either side of the center of the honeycomb structure portion 10 when the honeycomb structure portion 10 is viewed from the direction in which the cells 12 extend.

[0021] In the illustrated example, cylindrical electrode terminals are provided as the electrode portions 20, but the shape and size of the electrode terminals are not particularly limited. For example, the electrode terminals may be shaped like rectangular pillars or comb teeth. Although not illustrated, the electrode portions 20 may be configured by forming an electrode layer (not illustrated) on the outer peripheral wall 16 of the honeycomb structure portion 10 and providing the electrode terminals via this electrode layer. The thickness of the electrode layer is, for example, 100 μm to 5 mm.

[0022] An insulating member 31 made of an insulating material may be disposed in the insulating section 30. For example, from the viewpoint of space saving, the insulating member 31 is disposed in contact with the first honeycomb structure unit 1 and the second honeycomb structure unit 2. For example, from the viewpoint of ease of assembly, the insulating member 31 is preferably bonded to the first honeycomb structure unit 1 and the second honeycomb structure unit 2. The bonding method of the insulating member 31 is not particularly limited. For example, the insulating member 31 may be bonded to the honeycomb structure unit using an adhesive material or bonding parts. Furthermore, for example, the insulating member 31 may be formed integrally when the honeycomb structure unit (honeycomb structure section 10) is manufactured.

[0023] When the first honeycomb structure unit 1 is viewed from the extending direction of the cells 12, the insulating section 30 may have a region 40 formed therein where the honeycomb structure section 10 of the first honeycomb structure unit 1 does not overlap with the insulating member 31. In the illustrated example, when the first honeycomb structure unit 1 is viewed from the extending direction of the cells 12, a region 40 where the insulating member 31 does not exist is formed in the center of the honeycomb structure section 10 of the first honeycomb structure unit 1. As shown in Fig. 4, the insulating section 30 has a space 42 surrounded by an inner peripheral wall 38 of the insulating member 31. By forming the space 42 in the insulating section 30, pressure loss caused by fluid passing through the insulating section 30 can be reduced.

[0024] The insulating member 31 has partition walls 34 that define a plurality of cells 32 that extend (in the length direction) from the first end face 31a to the second end face 31b and can serve as fluid flow paths, and an outer peripheral wall 36 that is located on the periphery and surrounds the partition walls 34. The insulating member 31 is arranged so that the extension direction of its cells 32 is aligned with the extension direction of the cells 12 of the first honeycomb structure unit 1 and the extension direction of the cells 12 of the second honeycomb structure unit 2. The insulating member 31 has a honeycomb structure, which can reduce pressure loss caused by fluid passing through the insulating section 30. Note that the same explanation as for the honeycomb structure section 10 above can be applied to the details of the honeycomb structure of the insulating member 31.

[0025] When the insulating member 31 has a honeycomb structure, the aperture ratio of the honeycomb structure section 10 can be designed to be smaller than the aperture ratio of the insulating member 31. Specifically, from the viewpoint of ensuring a contact area with the fluid, the aperture ratio of the honeycomb structure section 10 can be designed to be small. On the other hand, from the viewpoint of reducing pressure loss caused by the fluid passing through the insulating section 30, the aperture ratio of the insulating member 31 can be designed to be large. The aperture ratio of the insulating member 31 is preferably 70% to 92%. Here, the aperture ratio of the insulating member 31 refers to the aperture ratio per unit area in a plane perpendicular to the extension direction of the cells 32 of the insulating member 31. Specifically, the aperture ratio of the insulating member 31 is the ratio of the sum of the areas of the void portions of the cells 32 to the total area of ​​the plane perpendicular to the extension direction of the cells 32 of the insulating member 31. In the illustrated example, the opening ratio of the insulating member 31 is the ratio of the total area of ​​the void portions of the cells 32 to the area of ​​the region surrounded by the outer wall 36 excluding the space portion 42 in a plane perpendicular to the extension direction of the cells 32 of the insulating member 31.

[0026] When the insulating member 31 has a honeycomb structure, the hydraulic diameter of the cells 12 of the honeycomb structure section 10 can be designed to be smaller than the hydraulic diameter of the cells 32 of the insulating member 31. Specifically, from the viewpoint of ensuring a contact area with the fluid, the hydraulic diameter of the cells 12 of the honeycomb structure section 10 can be designed to be small. On the other hand, from the viewpoint of reducing pressure loss caused by the fluid passing through the insulating section 30, the hydraulic diameter of the cells 32 of the insulating member 31 can be designed to be large. The hydraulic diameter of the cells 32 of the insulating member 31 is preferably 0.9 mm to 2 mm. Here, the hydraulic diameter of the cells 32 of the insulating member 31 is calculated by multiplying the perimeter (unit: mm) surrounded by the partition walls 34 and the cross-sectional area of ​​the cells 32 (unit: mm ２ ) and is calculated by the formula: 4 x (cross-sectional area) / (perimeter).

[0027] FIG. 5 is a cross-sectional view showing a schematic configuration of a modified honeycomb structure unit. In this modified example, the honeycomb structure unit 10 has first slits 17 and second slits 18. Specifically, the first slits 17 extend from the first portion P1 of the outer peripheral wall 16 (the side surface of the honeycomb structure unit 10) toward the second portion P2, which are opposed to each other. The second slits 18 extend from the second portion P2 of the outer peripheral wall 16 toward the first portion P1, which are opposed to each other. Such slits can function as electrical insulators. By forming the first slits 17 from the first portion P1 located between the pair of electrode units 20, 20, short-circuiting between the pair of electrode units 20, 20 can be effectively prevented, and the honeycomb structure unit 10 can generate heat stably. Furthermore, by forming the second slits 18 located between adjacent first slits 17, 17, the entire honeycomb structure unit 10 can generate heat more uniformly.

[0028] The volume resistivity of the honeycomb structure part 10 is, for example, 0.001 Ω·cm or more, preferably 0.01 Ω·cm or more, and more preferably 0.1 Ω·cm or more. Such a volume resistivity can suppress problems such as excessive current flow depending on the applied voltage. On the other hand, the volume resistivity of the honeycomb structure part 10 is, for example, 200 Ω·cm or less, and preferably 100 Ω·cm or less. Such a volume resistivity can generate sufficient heat when current is applied. The volume resistivity can be a value measured at a temperature of 25°C using a four-terminal method.

[0029] The honeycomb structure section 10 is preferably made of ceramics. By using ceramics, the volume resistivity can be satisfactorily satisfied. Ceramics also have a low thermal expansion coefficient and excellent shape stability.

[0030] The honeycomb structure 10 is made of, for example, a material containing silicon carbide. The honeycomb structure 10 is preferably made of a material containing, as a main component, a silicon carbide material or a silicon-silicon carbide composite material. Here, "containing, as a main component" means, for example, that the material contains 80 mass % or more, and preferably 90 mass % or more.

[0031] The silicon carbide material may be a material impregnated with silicon (silicon-impregnated silicon carbide). The silicon-silicon carbide composite material may be a material in which a plurality of silicon carbide particles are bonded together by metallic silicon. In the silicon-silicon carbide composite material, the silicon carbide particles may function as aggregate, and the silicon may function as a binder. By using such a material, the above-mentioned volume resistivity may be satisfactorily achieved. The volume resistivity of the honeycomb structure portion 10 may also be controlled by adjusting its porosity.

[0032] The honeycomb structure 10 can be obtained by drying and firing a molded body obtained by molding a molding material containing ceramic raw materials. When the honeycomb structure 10 is made of the silicon-silicon carbide composite material, the molding material can contain silicon carbide (e.g., silicon carbide powder) and metallic silicon (e.g., metallic silicon powder). Examples of other raw materials that can be contained in the molding material include a binder, a dispersion medium, and an additive.

[0033] Typically, the honeycomb structure 10 can be used as a catalyst carrier, and a catalyst can be supported on the partition walls 14. For example, CO, NO, etc. in a fluid (e.g., gas) passing through the cells 12 ｘ The catalyst can convert hydrocarbons and other substances into harmless substances through a catalytic reaction. The catalyst may preferably contain a noble metal (e.g., platinum, rhodium, palladium, ruthenium, indium, silver, gold), aluminum, nickel, zirconium, titanium, cerium, cobalt, manganese, zinc, copper, tin, iron, niobium, magnesium, lanthanum, samarium, bismuth, barium, or a combination thereof.

[0034] The volume resistivity of the electrode portion 20 varies depending on its configuration and constituent materials, but is typically 1×10 －６ The resistivity is Ω·cm to 10 Ω·cm, and preferably 0.01 Ω·cm to 10 Ω·cm.

[0035] The electrode section 20 may be made of any appropriate material. Examples of materials that can be used for the electrode section 20 include metals, conductive ceramics, and composites of metals and conductive ceramics (cermets). Examples of metals include Cr, Fe, Co, Ni, Si, and Ti. These may be used alone or in combination of two or more. When two or more types are used in combination, an alloy of two or more metals may be used. Examples of conductive ceramics include silicon carbide (SiC); tantalum silicide (TaSi ２ ), chromium silicide (CrSi ２ ) and other metal compounds such as metal silicides. Specific examples of composite materials (cermets) of metals and conductive ceramics include composite materials of metal silicon and silicon carbide, and composite materials of the above-mentioned metal silicides, metal silicon and silicon carbide. Specific examples of composite materials (cermets) of metals and conductive ceramics include composite materials in which one or more insulating ceramics such as alumina, mullite, zirconia, cordierite, silicon nitride, and aluminum nitride are added to one or more of the above-mentioned metals from the viewpoint of reducing thermal expansion.

[0036] When the electrode terminals constituting the electrode unit 20 are made of metal, the electrode terminals preferably have a comb-like shape. When the electrode terminals are made of conductive ceramics or a composite material (cermet) of metal and conductive ceramics, the electrode terminals preferably have a cylindrical or rectangular columnar shape. When the electrode terminals are made of conductive ceramics or a composite material (cermet) of metal and conductive ceramics, metal parts may be joined to both ends of the electrode terminals. The ceramic electrode terminals and the metal parts can be joined by, for example, crimping, welding, or using a conductive adhesive. Examples of materials for the metal parts include conductive metals such as iron alloys and nickel alloys.

[0037] It is preferable that at least a part of the electrode part 20 is made of the same material as the honeycomb structure part 10. Such a configuration can reduce the difference in thermal expansion coefficient between the honeycomb structure part 10 and the electrode part 20, thereby increasing the bonding strength between them. This can also contribute to improving productivity. The volume resistivity of the electrode part 20 can also be controlled by adjusting its porosity.

[0038] From the viewpoint of ensuring excellent insulation properties, the volume resistivity of the insulating member 31 is preferably 1×10 １０ Ω cm or more, more preferably 1×10 １２ On the other hand, the volume resistivity of the insulating member 31 is, for example, 1×10 １６ It is Ω·cm or less.

[0039] The insulating member 31 may be made of any appropriate material that can satisfy the above volume resistivity. The insulating member 31 is preferably made of ceramics. By using ceramics, the above volume resistivity can be satisfactorily satisfied. Ceramics also have a low thermal expansion coefficient and can have excellent shape stability. Furthermore, by using ceramics, the difference in thermal expansion coefficient with the honeycomb structure portion 10 can be reduced, thereby improving thermal shock resistance. Examples of ceramics include cordierite, mullite, alumina, spinel, silicon carbide, silicon nitride, and aluminum titanate. These may be used alone or in combination of two or more.

[0040] A catalyst may be supported on the partition walls 34 of the insulating member 31. For example, CO, NO, etc. in the fluid (e.g., gas) passing through the cells 32 may be removed by the catalyst. ｘ The catalyst can convert hydrocarbons and other substances into harmless substances through catalytic reactions. Specific examples of catalysts are as described above.

[0041] 6 is a cross-sectional view schematically showing the general configuration of a heating element according to a second embodiment of the present invention. The heating element 200 differs from the heating element 100 of the first embodiment in that the insulating section 30 does not have a space 42 (an inner peripheral wall 38 in the insulating member 31). Specifically, the heating element 200 differs from the heating element 100 of the first embodiment in that, when the first honeycomb structure unit 1 is viewed from the extension direction of the cells 12, the insulating section 30 does not have a region 40 in which the honeycomb structure section 10 of the first honeycomb structure unit 1 does not overlap with the insulating member 31. The absence of the space 42 in the insulating section 30 can provide excellent mechanical strength. Furthermore, even better insulation properties may be achieved.

[0042] The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the configurations shown in the above-described embodiment can be replaced with configurations that are substantially the same as those shown in the above-described embodiment, that have the same effects, or that can achieve the same purpose.

[0043] The heating element according to the embodiment of the present invention can be used, for example, as a catalyst carrier on which a catalyst is supported.

[0044] REFERENCE SIGNS LIST 1 honeycomb structure unit, 2 honeycomb structure unit, 10 honeycomb structure portion, 12 cell, 14 partition wall, 16 outer peripheral wall, 17 first slit, 18 second slit, 20 electrode portion, 30 insulating portion, 31 insulating member, 32 cell, 34 partition wall, 36 outer peripheral wall, 42 space portion, 100 heating element, 200 heating element.

Claims

1. A heating element including a plurality of honeycomb structure units each having a honeycomb structure portion which generates heat when an electric current is applied thereto, the honeycomb structure unit having partition walls which define a plurality of cells each extending from a first end face to a second end face and serving as a fluid flow path, the plurality of honeycomb structure units include a first honeycomb structure unit and a second honeycomb structure unit, the fluid having passed through the first honeycomb structure unit passes through an insulating portion formed between the first honeycomb structure unit and the second honeycomb structure unit, and passes through the second honeycomb structure unit; The insulating portion includes an insulating member made of an insulating material, and the insulating member has partition walls that partition and form a plurality of cells that serve as flow paths for a fluid. Heating element.

2. The heating element according to claim 1 , wherein each of the honeycomb structure units has a pair of electrode portions for electrically heating the honeycomb structure portion.

3. The honeycomb structure portion has an outer peripheral wall surrounding the partition wall, and the pair of electrode portions are provided on the outer peripheral wall, When the honeycomb structure section is viewed from the extending direction of the cells, the pair of electrode sections are disposed on one side of the center of the honeycomb structure section. The heating element according to claim 2.

4. 3. The heating element according to claim 1, wherein the extending direction of the cells of the first honeycomb structure unit is aligned with the extending direction of the cells of the second honeycomb structure unit.

5. The heating element according to claim 1 , wherein the insulating member is disposed in contact with the first honeycomb structure unit and the second honeycomb structure unit.

6. The heating element according to claim 1 , wherein the insulating member is bonded to the first honeycomb structure unit and the second honeycomb structure unit.

7. The heating element according to claim 1 , wherein an aperture ratio per unit area of ​​a surface of the honeycomb structure portion perpendicular to the cell extension direction is smaller than an aperture ratio per unit area of ​​a surface of the insulating member perpendicular to the cell extension direction.

8. The heating element according to claim 1 , wherein a hydraulic diameter of the cells of the honeycomb structure is smaller than a hydraulic diameter of the cells of the insulating member.

9. The heating element according to claim 1 , wherein when the first honeycomb structure unit is viewed from the extending direction of the cells, an area is formed in which the honeycomb structure portion of the first honeycomb structure unit does not overlap with the insulating member.

10. The heating element according to claim 9, wherein when the first honeycomb structure unit is viewed from the direction in which the cells extend, an area in which the insulating member is not present is formed in the center of the honeycomb structure portion of the first honeycomb structure unit.

11. The heating element according to claim 1 , wherein the insulating member is made of ceramics.

12. The heating element of claim 1 , wherein the insulating member includes a catalyst.

13. The heating element according to claim 1 , wherein the honeycomb structure portion is made of ceramics.

14. The heating element according to claim 1 , wherein the honeycomb structure includes a catalyst.