JP7034047B2 - Vehicle room heating heater element and its usage, and vehicle room heating heater - Google Patents

Description

The present invention relates to a heater element for heating a vehicle interior and a method of using the same. The present invention also relates to a heater for heating the passenger compartment.

From the viewpoint of protecting the global environment, there is an increasing demand for reduction of CO ₂ emissions from automobiles. In addition, from the viewpoint of achieving environmental standards in urban areas, there is an increasing demand for zero emissions of nitrogen oxides and the like from automobiles. Electric vehicles are attracting attention as measures that can deal with these issues. However, since the electric vehicle does not have an internal combustion engine which has been conventionally used as a heat source for heating, there is a problem that the heat source for heating is insufficient.

Therefore, a steam compression heat pump has been used for heating by effectively using the electric power of the battery (Patent Document 1). In the steam compression heat pump, the medium is compressed by an electric compressor, and heat is pumped from the cold outside air to the passenger compartment by using heat absorption and heat dissipation in the phase change between the gas phase and the liquid phase. Since the amount of heat that can be pumped is large, there is an advantage that electric energy can be used more effectively.

Further, a heater using Joule heat generated by electric resistance at the time of energization is also known (Patent Document 2). In a heater using Joule heat, a heating element is arranged in a heat exchanger, and a fluid passing through the heat exchanger is heated. A heater using Joule heat is effective when rapid heating at the start of the vehicle is required or when the outside air temperature is very low. As the heating element, it is known to use a PTC material in order to prevent thermal runaway.

On the other hand, a heater using a honeycomb-shaped heater element (hereinafter referred to as "honeycomb heater") is known. For example, Patent Document 3 describes a honeycomb structure for energization heat generation that is effective for heating exhaust gas from a gasoline engine, a diesel engine, and a combustion device. Further, Patent Document 4 also describes an electrically heatable honeycomb body for treating the exhaust gas of an internal combustion engine. Patent Document 4 describes an electrically heatable honeycomb body having a cavity through which a fluid can flow, having at least one current distribution structure, and the current distribution structure can be connected to a power source via a current supply body. At least one of a) a current supply body and b) a current distribution structure has at least one control element made of a material having a positive temperature coefficient (PTC), and the control element is a fluid flowing through the honeycomb body. Described is an electrically heatable honeycomb body, characterized in that it is at least thermally contacted.

Japanese Unexamined Patent Publication No. 2017-30724 Special Table 2015-591260 Japanese Patent No. 5261256 Japanese Unexamined Patent Publication No. 2008-215351

Although the heat pump is excellent from the viewpoint of thermal efficiency, the heat pump has problems that it is difficult to operate when the outside air is extremely low temperature and it is difficult to rapidly heat the vehicle interior when the vehicle is started. Therefore, while using the heat pump as the main heating, it is practical to use the heater using Joule heat as an auxiliary when rapid heating at the start of the vehicle is required or when the outside temperature is very low. Be done.

However, the conventional heater using Joule heat tends to be large in size, and has a problem of squeezing the space inside the vehicle. Therefore, it is desirable to provide a more compact heater. In this respect, the honeycomb heater can increase the heat transfer area per volume, which is considered to contribute to the miniaturization of the heater. However, the honeycomb structure for energization heat generation described in Patent Document 3 generates excessive heat because the honeycomb structure has NTC characteristics, and is difficult to adapt as a heater for heating a vehicle interior. Further, in the technique described in Patent Document 4, the temperature of the control element made of PTC material does not follow the temperature of the honeycomb body, and it cannot be said that the effect of suppressing excessive heat generation is sufficient as a heater for heating the passenger compartment. rice field. From the above, conventionally, there is no honeycomb heater that solves the above problem in the application for heating the passenger compartment of a vehicle such as an automobile or a train.

The present invention has been created in view of the above circumstances, and an object of the present invention is to provide a heater element for heating a vehicle interior, which can be miniaturized and has an improved effect of suppressing excessive heat generation by a PTC material. It is an object of the present invention to provide, in another embodiment, a method of using such a heater element for heating a vehicle interior. It is an object of the present invention to provide, in yet another embodiment, a vehicle compartment heating heater provided with such a vehicle interior heating heater element.

In the honeycomb heater described in Patent Document 4, since the control element made of PTC material is arranged on the outer peripheral side of the honeycomb structure with respect to the current distribution structure (see FIGS. 2 and 3 of Patent Document 4). The heat from the honeycomb structure is transferred to the control element made of PTC material via the current distribution structure, so that the response speed is slowed down. Therefore, in the technique of Patent Document 4, even if the honeycomb structure reaches an overheated state, heat is not rapidly transferred to the PTC material, so that excessive heat generation is likely to occur. Based on such findings, the present inventor uses a PTC thermistor for the honeycomb structure and the electrode portion (corresponding to the current distribution structure of Patent Document 4) in order to increase the response speed when the honeycomb structure reaches an overheated state. We have found that it is effective to place it between), and completed the present invention exemplified below.

[1]
It is a heater element for heating the passenger compartment of a vehicle.
A columnar honeycomb structure capable of energizing and generating heat, having an outer peripheral side wall and a partition wall arranged on the inner peripheral side of the outer peripheral side wall and forming a plurality of cells forming a fluid flow path from one bottom surface to the other bottom surface.
A pair of electrode portions formed so as to face the outer peripheral side of the outer peripheral side wall of the columnar honeycomb structure portion, and
A PTC thermistor arranged so as to cover the outer peripheral side wall of the columnar honeycomb structure portion at a position sandwiched between the outer peripheral side wall of the columnar honeycomb structure portion and at least one electrode portion of the pair of electrode portions.
A heater element for heating the passenger compartment.
[2]
The ratio (S / V) of the total area S of the portion covered with the outer peripheral side wall of the columnar honeycomb structure by the PTC thermistor to the volume V of the columnar honeycomb structure is 0.1 cm ² / cm ³ or more. The heater element for heating the passenger compartment according to [1].
[3]
The heater element for heating a vehicle interior according to [2], wherein the S / V is 0.2 cm ² / cm ³ or more.
[4]
The heater element for heating a vehicle interior according to any one of [1] to [3], wherein the plurality of cells are arranged radially in a cross section in a direction orthogonal to the fluid flow path of the plurality of cells.
[5]
The heater element for heating a vehicle interior according to any one of [1] to [4], wherein the PTC thermistor is made of a PTC material having a Curie point of 100 ° C. or higher and 250 ° C. or lower.
[6]
The heater element for heating a vehicle interior according to any one of [1] to [5], wherein the columnar honeycomb structure portion contains Si-bonded SiC.
[7]
The vehicle interior according to any one of [1] to [6], wherein the PTC thermistor is arranged so that at least one of the electrode portions does not come into direct contact with the outer peripheral side wall of the columnar honeycomb structure portion. Heater element for heating.
[8]
A PTC thermistor is disposed at a position sandwiched between the outer peripheral side wall of the columnar honeycomb structure portion and each electrode portion of the pair of electrode portions.
An electrically insulating layer located between a part of at least one PTC thermistor and the outer peripheral side wall of the columnar honeycomb structure portion, and the current distribution in the honeycomb structure portion when a voltage is applied to the pair of electrode portions. The heater element for heating a passenger compartment according to any one of [1] to [7], further comprising an electrically insulating layer extended at a position capable of enhancing uniformity.
[9]
The total area S of the portion where the outer peripheral side wall is covered with the PTC thermistor and the area Se obtained by subtracting the area of the portion where the outer peripheral side wall is in contact with the electrical insulating layer from the total area S are 0.3 ≦ Se / S <. The heater element according to [8], which satisfies 1.
[10]
It is a heater element for heating the passenger compartment of a vehicle.
Energization having an outer peripheral side wall, an inner peripheral side wall, and a partition wall disposed between the outer peripheral side wall and the inner peripheral side wall and partitioning a plurality of cells forming a fluid flow path from one bottom surface to the other bottom surface. Hollow honeycomb structure that can generate heat,
The outer electrode portion formed on the outer peripheral side of the outer peripheral side wall of the hollow honeycomb structure portion,
The inner electrode portion formed on the inner peripheral side of the inner peripheral side wall of the hollow honeycomb structure portion,
as well as,
It is arranged so as to cover the inner peripheral side wall of the hollow honeycomb structure portion at a position sandwiched between the inner peripheral side wall of the hollow honeycomb structure portion and the inner electrode portion, and / or. A PTC thermista, which is arranged so as to cover the outer peripheral side wall of the hollow honeycomb structure portion at a position sandwiched between the outer peripheral side wall of the hollow honeycomb structure portion and the outer electrode portion.
A heater element for heating the passenger compartment.
[11]
The ratio (S / V) of the total area S of the portion covered with the inner peripheral side wall and / or the outer peripheral side wall of the hollow honeycomb structure portion by the PTC thermistor with respect to the volume V of the hollow honeycomb structure portion is 0. The heater element for heating the passenger compartment according to [10], which is 1 cm ² / cm ³ or more.
[12]
The heater element for heating a vehicle interior according to [11], wherein the S / V is 0.2 cm ² / cm ³ or more.
[13]
The heater element for heating a passenger compartment according to any one of [10] to [12], wherein the plurality of cells are arranged radially in a cross section in a direction orthogonal to the flow path of the fluid of the plurality of cells.
[14]
The heater element for heating a vehicle interior according to any one of [10] to [13], wherein the PTC thermistor is made of a PTC material having a Curie point of 100 ° C. or higher and 250 ° C. or lower.
[15]
The heater element for heating a vehicle interior according to any one of [10] to [14], wherein the hollow honeycomb structure portion contains Si-bonded SiC.
[16]
When the PTC thermistor is arranged so as to cover the inner peripheral side wall of the hollow honeycomb structure portion, the PTC thermistor has a portion where the inner electrode portion directly contacts the inner peripheral side wall of the hollow honeycomb structure portion. When the PTC thermistor is arranged so as not to cover the outer peripheral side wall of the hollow honeycomb structure portion, the outer electrode portion of the PTC thermistor is arranged with the outer peripheral side wall of the hollow honeycomb structure portion. The heater element for heating a passenger compartment according to any one of [10] to [15], which is arranged so as not to have a portion that comes into direct contact with the vehicle interior.
[17]
The method for using a heater element according to any one of [1] to [16], wherein a voltage of 200 V or more is applied between two electrodes.
[18]
The method of using the heater element according to [17], which comprises passing a gas of -60 ° C to 20 ° C through the cell.
[19]
The heater element according to any one of [1] to [16].
An inflow pipe that communicates the outside air or vehicle interior air with the bottom surface of one of the heater elements,
A battery for applying a voltage to the heater element, and an outflow pipe that communicates the other bottom surface of the heater element with the passenger compartment.
A heater for heating the passenger compartment.

According to the vehicle interior heating heater element according to the embodiment of the present invention, the heat transfer area per volume can be increased by the honeycomb structure, so that the heater element can be miniaturized. Further, according to the heater element according to the embodiment of the present invention, the PTC thermistor is arranged so as to be sandwiched between at least one electrode portion and the outer peripheral side wall or the inner peripheral side wall of the honeycomb structure portion. The heat of the part is quickly transferred to the PTC thermistor. This makes it possible to improve the effect of suppressing excessive heat generation by the PTC thermistor.

It is a schematic perspective view of the heater element which concerns on 1st Embodiment of this invention, when the bottom surface of the honeycomb structure part is rectangular shape. It is a schematic perspective view of the heater element which concerns on 1st Embodiment of this invention, when the bottom surface of the honeycomb structure part is square shape. It is a schematic perspective view of the heater element which concerns on 1st Embodiment of this invention, when the bottom surface of the honeycomb structure part has an oval shape. Regarding the heater element according to the first embodiment of the present invention, a schematic perspective when the bottom surface of the honeycomb structure portion is square and the electrical insulating layer is sandwiched between the outer peripheral side wall of the honeycomb structure portion and the PTC thermistor. It is a figure. It is a schematic perspective view of the heater element which concerns on 1st Embodiment of this invention, when the bottom surface of the honeycomb structure part is circular shape. It is a partial schematic diagram which shows the cell arranged radially when observed from the direction orthogonal to the flow path of a cell about the heater element which concerns on 1st Embodiment of this invention. It is a schematic diagram which shows the structural example of the heater for room heating which concerns on this invention.

Next, an embodiment of the present invention will be described in detail with reference to the drawings. It is understood that the present invention is not limited to the following embodiments, and design changes, improvements, etc. may be appropriately made based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. Should be.

(1. Heater element)
The heater element according to the present invention can be suitably used as a heater element for heating the passenger compartment of a vehicle. Vehicles include, but are not limited to, automobiles and trains. Vehicles include, but are not limited to, gasoline vehicles, diesel vehicles, fuel cell vehicles, electric vehicles and plug-in hybrid vehicles. The heater element according to the present invention can be particularly suitably used for a vehicle having no internal combustion engine such as an electric vehicle and a train.

(1.1 First Embodiment of Heater Element)
FIG. 1-1, FIG. 1-2, and FIG. 1-3 show schematic perspective views of the heater element 100 according to the first embodiment of the present invention, respectively. The heater element 100 includes an outer peripheral side wall 112 and a partition wall 113 which is disposed on the inner peripheral side of the outer peripheral side wall 112 and forms a plurality of cells 115 which form a fluid flow path from one bottom surface 114 to the other bottom surface 116. It is provided with a columnar honeycomb structure capable of generating heat by energization. Further, the heater element 100 includes a pair of electrode portions 120 formed so as to face the outer peripheral side of the outer peripheral side wall 112 of the columnar honeycomb structure portion. Further, the heater element 100 covers the outer peripheral side wall 112 of the columnar honeycomb structure portion at a position sandwiched between the outer peripheral side wall 112 of the columnar honeycomb structure portion and at least one electrode portion 120 of the pair of electrode portions 120. The PTC thermistor 122 is provided so as to be provided.

(1.1.1 Columnar honeycomb structure)
The columnar honeycomb structure has, for example, a polygonal columnar surface having a polygonal bottom surface (quadrangle (rectangle (see Fig. 1-1)), square (see Fig. 1-2), pentagon, hexagon, heptagon, octagon, etc.). The bottom surface can be any shape such as a circular columnar shape (cylindrical column) (see FIG. 2) and an oval-shaped bottom surface (see FIG. 1-3). If the bottom surface is polygonal, the corners may be chamfered. Further, the columnar honeycomb structure can be made hollow.

The shape of the cell in the cross section orthogonal to the flow path of the cell is not limited, but is preferably a quadrangle (rectangle, square), hexagon, octagon, or a combination of two or more thereof. Of these, squares and hexagons are preferred. By making the cell shape in this way, it is possible to reduce the pressure loss when gas is passed through the honeycomb structure portion. For example, in the columnar honeycomb structure portion of the heater element 100 shown in FIG. 1-1, the shape of the cell in the cross section orthogonal to the flow path of the cell is square.

A plurality of cells may be arranged radially in a cross section orthogonal to the cell flow path. FIG. 2-2 shows an example in which a plurality of cells are arranged radially with respect to the second embodiment described later. In the example shown in FIG. 2-2, each of the plurality of cells has a pair of partition walls extending from the center side of the columnar honeycomb structure toward the outer peripheral side, and partition walls on the central side and the outer peripheral side connecting the pair of partition walls. And, the partition is formed by. More specifically, in the example shown in FIG. 2-2 (a), in the cross section orthogonal to the cell flow path, each of the plurality of cells 115 is directed from the center side to the outer peripheral side of the columnar honeycomb structure portion. It is partitioned by a pair of extending linear partition walls 113a and a pair of concentric arc-shaped partition walls 113b. In the embodiment shown in FIG. 2-2 (b), in the cross section orthogonal to the cell flow path, each of the plurality of cells 115 has a hexagonal shape, and the columnar honeycomb structure portion is directed from the center side to the outer peripheral side. The partition is formed by a pair of extending linear partition walls 113c and a polygonal linear partition wall 113d on the center side and the outer peripheral side connecting the pair of partition walls 113c. In addition, in FIG. 2-2, the part shown by the dotted line means that a plurality of cells are arranged radially in the same manner as the part shown in the figure.

From the viewpoint of ensuring the gas flow rate, the lower limit of the size of each bottom area of the columnar honeycomb structure (excluding the hollow columnar honeycomb structure if it is hollow) should be 50 cm ² or more. It is more preferably 70 cm ² or more, and even more preferably 100 cm ² or more. From the viewpoint of making the heater element compact, the upper limit of the size of each bottom area of the columnar honeycomb structure is preferably 300 cm ² or less, more preferably 200 cm ² or less, and further 150 cm ² or less. It is even more preferable to do so. The size of each bottom area of the columnar honeycomb structure can be, for example, 50 to 300 cm ² .

From the viewpoint of making the heater element compact, the upper limit of the height of the columnar honeycomb structure (flow path length of each cell) is preferably, for example, 40 mm or less, more preferably 20 mm or less, and 10 mm or less. It is even more preferable that the thickness is 5 mm or less, and even more preferably. From the viewpoint of ensuring heating performance and strength, the lower limit of the height of the columnar honeycomb structure (flow path length of each cell) is preferably 3 mm or more. The height of the columnar honeycomb structure (flow path length of each cell) can be, for example, 3 to 40 mm.

It is advantageous to make the partition wall thin from the viewpoint of suppressing the initial current at the time of energization from becoming excessive and from the viewpoint of suppressing the ventilation resistance and suppressing the output of the blower. Therefore, the upper limit of the average thickness of the partition wall 113 in the honeycomb structure portion is preferably 0.15 mm or less, more preferably 0.13 mm or less, and further preferably 0.10 mm or less. However, from the viewpoint of ensuring the strength of the honeycomb structure portion, the lower limit of the average thickness of the partition wall 113 is preferably 0.02 mm or more, more preferably 0.04 mm or more, and 0.06 mm or more. It is even more preferable to have.

In the present invention, the thickness of the partition wall refers to the length at which the line segment crosses the partition wall when the centers of gravity of adjacent cells are connected by a line segment in a cross section orthogonal to the flow path of the cell. The average thickness of partition walls refers to the average value of the thickness of all partition walls.

The columnar honeycomb structure preferably has a cell density of 40 cells / cm ² or more, and more preferably 80 cells / cm ² or more. By limiting the cell density to the above range in combination with the above-mentioned suitable range of the average thickness of the partition wall, it is possible to obtain a heater element suitable for rapid heating while suppressing the initial current. From the viewpoint of suppressing the ventilation resistance and suppressing the output of the blower, the cell density of the columnar honeycomb structure portion is preferably 150 cells / cm ² or less, and more preferably 120 cells / cm ² or less. In the present invention, the cell density of the columnar honeycomb structure is obtained by dividing the number of cells by the area of each bottom surface of the columnar honeycomb structure (excluding the hollow columnar honeycomb structure if the columnar honeycomb structure is hollow). The value.

From the viewpoint of suppressing ventilation resistance, it is advantageous to have a large aperture ratio (OFA). Therefore, the lower limit of the aperture ratio on each bottom surface of the columnar honeycomb structure portion is preferably 0.7 or more, more preferably 0.75 or more, and even more preferably 0.8 or more. From the viewpoint of ensuring thermal conductivity, the upper limit of the aperture ratio on each bottom surface of the columnar honeycomb structure is preferably 0.9 or less, more preferably 0.88 or less, and 0.85 or less. It is even more preferable to have. In the present invention, the aperture ratio on each bottom surface of the columnar honeycomb structure is the cell on the bottom surface with respect to the area of each bottom surface including the opening of the cell (if the columnar honeycomb structure is hollow, that portion is excluded). Refers to the ratio of the area of the opening of.

The material of the columnar honeycomb structure is not particularly limited as long as it can generate heat by energization, and metal, ceramics, or the like can be used. A columnar honeycomb structure in which a gas such as outside air or vehicle interior air generates heat from flowing in from one bottom surface of the columnar honeycomb structure to passing through a plurality of cells 115 and flowing out from the other bottom surface. It can be heated by heat transfer from the part. In particular, from the viewpoint of achieving both heat resistance and conductivity, the material of the columnar honeycomb structure portion preferably contains Si-bonded SiC or SiC as a main component, and more preferably Si-bonded SiC or SiC. In order to reduce the electrical resistivity of the columnar honeycomb structure, tantalum silicate (TaSi ₂ ) and / or chromium silicate (CrSi ₂ ) can also be blended. The fact that the columnar honeycomb structure portion contains Si-bonded SiC as a main component means that the columnar honeycomb structure portion contains Si-bonded SiC (total mass) in an amount of 90% by mass or more of the entire honeycomb structure portion. Here, the Si-bonded SiC contains silicon carbide particles as an aggregate and silicon as a binder for binding silicon carbide particles. Further, the fact that the columnar honeycomb structure portion contains SiC as a main component means that the columnar honeycomb structure portion contains SiC (total mass) in an amount of 90% by mass or more of the entire honeycomb structure portion.

As the material of the columnar honeycomb structure, it is also possible to use a PTC (Positive Temperature Coefficient) material typified by barium titanate. That is, the columnar honeycomb structure itself may have a characteristic that when the temperature rises and exceeds the Curie point, the resistance value rises sharply and it becomes difficult for electricity to flow. However, from the viewpoint of selecting a honeycomb material that satisfies thermal conductivity, strength, and appropriate electrical resistance, a material having NTC (Negative Temperature Coefficient) characteristics such as Si-bonded SiC or SiC is generally preferable.

(1.1.2 Electrode part)
The heater element 100 includes a pair of electrode portions 120 formed so as to face the outer peripheral side of the outer peripheral side wall 112 of the columnar honeycomb structure portion. When a voltage is applied between the pair of electrode portions, the columnar honeycomb structure portion can be energized and generate heat by Joule heat. In a preferred embodiment, the pair of electrode portions 120 are extended in a band shape in the flow path direction of the cell on the outer peripheral side of the outer peripheral side wall 112 of the honeycomb structure portion with the central axis of the honeycomb structure portion interposed therebetween. As a result, the honeycomb structure can suppress the deviation of the current flowing in the honeycomb structure portion when a voltage is applied between the pair of electrode portions 120, and can suppress the deviation of the temperature distribution in the honeycomb structure portion. .. An electric wire can be connected to each electrode portion 120 by diffusion bonding, a mechanical pressurizing mechanism, welding, or the like, and power can be supplied from a battery, for example, via the electric wire.

For each electrode portion 120, for example, an electrode containing at least one selected from Cu, Ag, Al and Si can be used. It is also possible to use an ohmic electrode that can obtain ohmic contact with the PTC thermistor described later. The ohmic electrode contains, for example, at least one selected from Au, Ag and In as the base metal and at least one selected from Ni, Si, Ge, Sn, Se and Te for n-type semiconductors as the dopant. Ohmic electrodes can be used.

It is preferable that each of the pair of electrode portions 120 is formed in a band shape extending from one bottom surface to the other bottom surface in the flow path direction of the cell of the columnar honeycomb structure portion. As described above, since the pair of electrode portions 120 are arranged between both bottom surfaces of the columnar honeycomb structure portion, the current flowing in the columnar honeycomb structure portion when a voltage is applied between the pair of electrode portions 120. The bias can be suppressed more effectively. Then, by suppressing the bias of the current flowing in the columnar honeycomb structure portion, the bias of the temperature distribution in the honeycomb structure portion can be suppressed more effectively. "The pair of electrode portions are each formed in a band shape extending from one bottom surface to the other bottom surface in the cell flow path direction of the columnar honeycomb structure portion" means that one of the cell flow path direction ends of each electrode portion 120 is formed. It means that the portion is in contact with the peripheral edge of one bottom surface of the columnar honeycomb structure portion, and the end portion of each electrode portion 120 in the direction of the other cell flow path is in contact with the peripheral edge of the other bottom surface of the columnar honeycomb structure portion.

(1.1.3 PTC thermistor)
The heater element 100 covers the outer peripheral side wall 112 of the columnar honeycomb structure portion at a position sandwiched between the outer peripheral side wall 112 of the columnar honeycomb structure portion and at least one electrode portion 120 of the pair of electrode portions 120. The PTC thermistor 122 is provided. By having such a sandwich structure, the heat from the columnar honeycomb structure portion is quickly transferred to the PTC thermistor 122. Therefore, when the columnar honeycomb structure portion overheats, the PTC thermistor 122 operates quickly and the electrode portion. It is possible to suppress the current passing through the columnar honeycomb structure via 120. The PTC thermistor 122 may be provided only at a position sandwiched between the outer peripheral side wall 112 of the columnar honeycomb structure portion and one of the electrode portions 120 of the pair of electrode portions 120, or may be provided with the outer peripheral side wall 112 of the columnar honeycomb structure portion. It may be provided at a position sandwiched between the pair of electrode portions 120 and both electrode portions 120. When the PTC thermistors are provided for both electrode portions, it is preferable to provide the PTC thermistors for each electrode portion separately in order to prevent current bias.

From the viewpoint of enhancing the overheat prevention performance, the lower limit of the ratio (S / V) of the total area S of the portion covered by the outer peripheral side wall 112 of the columnar honeycomb structure portion by the PTC thermistor 122 with respect to the volume V of the columnar honeycomb structure portion is It is preferably 0.1 cm ² / cm ³ or more, more preferably 0.2 cm ² / cm ³ or more, and even more preferably 0.4 cm ² / cm ³ or more. In addition, although it is possible to obtain S / V by making the shape more complicated than covering all the sides of the simple shape of the circular cross section and the square cross section, the current distribution becomes complicated and the temperature distribution tends to be non-uniform. Therefore, from the viewpoint of maintaining the simple shape, the upper limit of S / V is preferably 0.8 cm ² / cm ³ or less, more preferably 0.7 cm ² / cm ³ or less, and 0.6 cm ² or less. It is even more preferable that it is / cm ³ or less. Here, the volume V of the honeycomb refers to a volume value measured based on the external dimensions of the columnar honeycomb structure portion (the hollow portion is not included in the volume V). Further, the total area S refers to the total area of the portion where the outer peripheral side wall of the columnar honeycomb structure portion is covered by the plurality of PTC thermistors when a plurality of PTC thermistors are installed.

If the total area S of the portion covered with the outer peripheral side wall of the columnar honeycomb structure portion by the PTC thermistor is increased in order to increase the S / V, the distance between the PTC thermistors arranged for each electrode portion becomes short. There will be a short electrical conduction path in the honeycomb structure. In this case, since the electric resistance is low, the current is concentrated and flows in that portion, the temperature becomes locally high, and the temperature becomes non-uniform. Therefore, if the portion of the honeycomb structure where the electrical conduction path is shortened is insulated with respect to electrical conduction and heat conduction is possible, heat transfer to the PTC thermista is good, so the effect of preventing overheating is excellent, and Since the short portion of the electric conduction path is not formed, the effect of improving the heat generation uniformity in the honeycomb structure can be obtained.

Therefore, the heater element according to the present invention is, in one embodiment,.
A PTC thermistor is disposed at a position sandwiched between the outer peripheral side wall of the columnar honeycomb structure portion and each electrode portion of the pair of electrode portions.
An electrically insulating layer located between a part of at least one PTC thermistor and the outer peripheral side wall of the columnar honeycomb structure portion, and the current distribution in the honeycomb structure portion when a voltage is applied to the pair of electrode portions. It is further provided with an electrically insulating layer extended at a position where the uniformity can be enhanced.

In a preferred embodiment, a pair of electrically insulating layers are arranged at positions sandwiched between a part of each PTC thermistor and the outer peripheral side wall of the columnar honeycomb structure portion.

As the arrangement position of the electric insulating layer capable of improving the uniformity of the current distribution in the honeycomb structure portion when a voltage is applied to the pair of electrode portions, the PTC thermistors arranged for each electrode portion are peripheral to each other. The edge of each PTC thermistor closest to the direction is mentioned. The electrically insulating layer may be provided on one edge of each PTC thermistor, or may be provided on both edges of each PTC thermistor. Here, the circumferential direction refers to a direction perpendicular to the height direction (direction in which the cell extends) of the honeycomb structure portion.

The smaller the ratio (Se / S) of the area Se to the total area S of the portion where the outer peripheral side wall is covered with the PTC thermistor, excluding the area of the portion where the outer peripheral side wall is in contact with the electrical insulating layer from the total area S. , It is easy to obtain the effect of improving the heat generation uniformity in the honeycomb structure. On the other hand, if Se / S is too small, the effect of preventing overheating tends to decrease. Therefore, 0.3 ≦ Se / S <1 is satisfied in the preferred embodiment, 0.3 ≦ Se / S ≦ 0.8 is satisfied in the more preferable embodiment, and 0. 4 ≦ Se / S ≦ 0.7 is satisfied.

For example, FIG. 1-4 shows a modification of the embodiment of FIG. 1-2 modified so that the electrical insulating layer 118 is partially sandwiched between the outer peripheral side wall 112 of the honeycomb structure portion and the PTC thermistor 122. It is shown. In the embodiment of FIG. 1-4, the pair of opposing PTC thermistors 122 extend in an L-shaped cross section on the voltage application surface of the outer peripheral side wall 112 and the adjacent side surface of the outer peripheral side wall 112 perpendicular to the voltage application surface, respectively. It is set up. The electrical insulating layer 118 is installed so as to cover the adjacent side surface of the outer peripheral side wall 112 at a position sandwiched between each PTC thermistor 122 and the outer peripheral side wall 112.

The material of the electrically insulating layer 118 is not particularly limited, but for example, oxides such as SiO _2, Al ₂ O ₃ , MgO, ZrO ₂ , TiO ₂ , and CeO ₂ and nitrides such as AlN and Si ₃ N ₄ are nitrided. Things can be mentioned. These may be used alone or in combination of two or more. Examples of the method for forming the electrically insulating layer 118 include a dry method and a wet method. Examples of the dry method include a CVD (chemical vapor deposition) method, a PVD (physical vapor deposition) method, an ion plating method, a sputtering method, and an electrostatic spray method. Examples of the wet method include a method in which a slurry for forming an electric insulating layer is applied to a predetermined position on the outer peripheral side wall, dried, and then fired.

The PTC thermistor 122 is preferably arranged so that at least one of the electrode portions 120 does not come into direct contact with the outer peripheral side wall 112 of the columnar honeycomb structure portion. According to this configuration, when the PTC thermistor is operated, the current path can be completely cut off, so that the effect of enhancing the overheat prevention performance can be obtained.

From the viewpoint of having PTC characteristics, the PTC thermistor 122 is preferably a ceramic composed of a material containing barium titanate as a main component, and is a ceramic composed of a material containing 70% by mass or more of barium titanate. It is more preferable that the ceramic is made of a material containing 90% by mass or more of barium titanate. It is preferable that the ceramics contain one or more additives such as rare earth elements in order to obtain desired PTC characteristics. Additives include semiconductor agents such as Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, and low temperatures such as Sr, Sn and Zr. Side shifters, high temperature side shifters such as (Bi-Na), (Bi-K), property improvers such as Mn, metal oxides such as vanadium oxide and ytterbium oxide (especially oxides of rare earth elements). , And conductor powders such as carbon black and nickel. Other PTC materials include composite materials containing cristobalite phase SiO ₂ as a base material and a conductive filler. As a substitute for the cristobalite phase SiO ₂ base material, tridimite phase SiO ₂ , cristobalite phase AlPO ₄ , and tridimite phase AlPO ₄ can also be used.

The lower limit of the Curie point of the material constituting the PTC thermistor 122 is preferably 100 ° C. or higher, more preferably 125 ° C. or higher, and 150 ° C. or higher from the viewpoint of efficiently heating air for heating. It is even more preferable to have. Further, the upper limit of the Curie point of the material constituting the PTC thermistor 122 is preferably 250 ° C. or lower, preferably 225 ° C. or lower, from the viewpoint of safety as a component placed in or near the vehicle interior. Is more preferable, and it is even more preferable that the temperature is 200 ° C. or lower.

The Curie point of the material constituting the PTC thermistor 122 can be adjusted by the type of shifter and the amount of addition. For example, the Curie point of barium titanate (BaTIO ₃ ) is about 120 ° C., but the Curie point is shifted to the low temperature side by substituting a part of Ba and Ti with one or more of Sr, Sn and Zr. Can be done. Further, by substituting a part of Ba with Pb, the Curie temperature can be shifted to the high temperature side.

In the present invention, the Curie point is measured by the following method. The sample is attached to a sample holder for measurement, mounted in a measuring tank (eg, MINI-SUBZERO MC-810P manufactured by Tabi Espec), and the change in the electrical resistance of the sample with respect to the temperature change when the temperature rises from 10 ° C. Measure using a DC resistance meter (eg, multimeter 3478A manufactured by YHP). According to the electrical resistance-temperature plot obtained by the measurement, the temperature at which the resistance value becomes twice the resistance value at 20 ° C. is defined as the Curie point.

The lower limit of the average thickness of the PTC thermistor 122 is preferably 0.5 mm or more, more preferably 1 mm or more, still more preferably 2 mm or more, from the viewpoint of enhancing the overheat prevention performance. The upper limit of the average thickness of the PTC thermistor 122 is preferably 50 mm or less, more preferably 40 mm or less, and further preferably 30 mm or less, from the viewpoint of not excessively increasing the initial electric resistance value as a whole. More preferred. The average thickness of the PTC thermistor 122 is obtained as an average value when the thickness of the PTC thermistor 122 is arbitrarily measured at 10 or more points in a cross section orthogonal to the flow path of the cell.

(1.2 Second Embodiment of Heater Element)
FIG. 2 shows a schematic perspective view of the heater element 200 according to the second embodiment of the present invention. The heater element 200 is arranged between the outer peripheral side wall 112, the inner peripheral side wall 117, the outer peripheral side wall 112, and the inner peripheral side wall 117, and forms a flow path of the fluid from one bottom surface to the other bottom surface. A hollow honeycomb structure portion capable of generating heat by energization is provided with a partition wall 113 for forming a partition. Further, the heater element 200 has an outer electrode portion 120a formed on the outer peripheral side of the outer peripheral side wall 112 of the hollow honeycomb structure portion and an inner electrode portion formed on the inner peripheral side of the inner peripheral side wall 117 of the hollow honeycomb structure portion. 120b is provided. Further, the heater element 200 is arranged so as to cover the inner peripheral side wall 117 of the hollow honeycomb structure portion at a position sandwiched between the inner peripheral side wall 117 of the hollow honeycomb structure portion and the inner electrode portion 120b. And / or arranged so as to cover the outer peripheral side wall 112 of the hollow honeycomb structure portion at a position sandwiched between the outer peripheral side wall 112 of the hollow honeycomb structure portion and the outer electrode portion 120a. , PTC thermista 122.

(1.2.1 Columnar honeycomb structure)
The overall shape of the hollow honeycomb structure and the shape of the cell are the same as those described in the columnar honeycomb structure described in the first embodiment, except that the hollow honeycomb structure is limited, and therefore detailed description thereof is omitted. do. However, in the second embodiment, since the electrode portions are arranged on both the outer peripheral side and the inner peripheral side of the hollow honeycomb structure portion, by arranging the cells radially, electricity easily flows in the radial direction. .. Therefore, arranging the cells in a radial pattern is particularly advantageous in that the uniform heating performance is improved when the electrode portions are arranged on both the outer peripheral side and the inner peripheral side of the hollow honeycomb structure portion as in the present embodiment. It is advantageous.

The size, height, average thickness of the partition wall, cell density, aperture ratio, and material of each bottom area of the hollow honeycomb structure are the same as those described in the columnar honeycomb structure described in the first embodiment. Explanation is omitted.

From the viewpoint of ensuring the area where the PTC material contacts the honeycomb, the ratio of the area occupied by the hollow portion to the cross-sectional area of the entire hollow honeycomb structure including the hollow portion and the cell opening in the cross section orthogonal to the cell flow path is It is preferably 5% or more, and more preferably 10% or more. Further, from the viewpoint of sufficiently securing the honeycomb portion and suppressing the flow resistance of the gas, the hollow portion occupies the cross-sectional area of the entire hollow honeycomb structure including the hollow portion and the cell opening in the cross section orthogonal to the cell flow path. The area ratio is preferably 80% or less, more preferably 60% or less, and even more preferably 50% or less. The electrode portion and the PTC thermistor are not considered in the calculation of the area occupied by the hollow portion.

(1.2.2 Electrode part)
The heater element 200 includes an outer electrode portion 120a formed on the outer peripheral side of the outer peripheral side wall 112 of the hollow honeycomb structure portion and an inner electrode portion 120b formed on the inner peripheral side of the inner peripheral side wall 117 of the hollow honeycomb structure portion. Be prepared. The hollow honeycomb structure can be energized by applying a voltage between the pair of electrodes and generate heat by Joule heat. In a preferred embodiment, from the viewpoint of uniform heat generation, the outer electrode portion 120a is formed so as to cover the entire outer peripheral side of the outer peripheral side wall of the hollow honeycomb structure portion. Further, in a preferred embodiment, from the viewpoint of uniform heat generation, the inner electrode portion 120b is formed so as to cover the entire inner peripheral side of the inner peripheral side wall 117 of the hollow honeycomb structure portion. As a result, the honeycomb structure can suppress the deviation of the current flowing in the honeycomb structure portion when a voltage is applied between the pair of electrode portions 120a and 120b, and suppress the deviation of the temperature distribution in the honeycomb structure portion. Can be done. As shown in FIG. 2-2 (a), the inner electrode portion 120b can be provided so as to completely close the hollow portion of the honeycomb structure portion, thereby increasing the structural strength of the heater element. Can be done. An electric wire can be connected to each of the electrode portions 120a and 120b by diffusion bonding, a mechanical pressurizing mechanism, welding, or the like, and power can be supplied from a battery, for example, via the electric wire.

Since the materials of the electrode portions 120a and 120b are the same as those described in the electrode portions described in the first embodiment, detailed description thereof will be omitted.

(12.3 PTC thermistor)
The heater element 200 is arranged so as to cover the inner peripheral side wall 117 of the hollow honeycomb structure portion at a position sandwiched between the inner peripheral side wall 117 of the hollow honeycomb structure portion and the inner electrode portion 120b. A PTC thermistor 122 can be provided. Alternatively or additionally, the heater element 200 covers the outer peripheral side wall 112 of the hollow honeycomb structure at a position sandwiched between the outer peripheral side wall 112 of the hollow honeycomb structure and the outer electrode portion 120a. The PTC thermistor 122 is provided.

By having such a sandwich structure of the PTC thermistor, the heat from the columnar honeycomb structure portion is rapidly transferred to the PTC thermistor 122, so that the PTC thermistor 122 operates quickly when the columnar honeycomb structure portion overheats. It is possible to suppress the current passing through the columnar honeycomb structure portion via the electrode portion 120. From the viewpoint of enhancing the overheat prevention performance, it is preferable that at least the PTC thermistor is arranged on the outer peripheral electrode side where the covering area can be increased.

From the viewpoint of enhancing the overheat prevention performance, the ratio of the total area S of the portion covered with the inner peripheral side wall and / or the outer peripheral side wall 112 of the hollow honeycomb structure portion by the PTC thermistor 122 to the volume V of the columnar honeycomb structure portion (S). The lower limit of / V) is preferably 0.1 cm ² / cm ³ or more, more preferably 0.2 cm ² / cm ³ or more, and even more preferably 0.4 cm ² / cm ³ or more. preferable. Further, from the viewpoint of maintaining a simple shape, the upper limit of S / V is preferably 0.8 cm ² / cm ³ or less, more preferably 0.7 cm ² / cm ³ or less, and 0.6 cm ² or less. It is even more preferable that it is / cm ³ or less. Here, the volume V of the honeycomb refers to a volume value measured based on the external dimensions of the columnar honeycomb structure portion (the hollow portion is not included in the volume V). Further, the total area S refers to the total area of the portion where the inner peripheral side wall and / or the outer peripheral side wall of the columnar honeycomb structure portion is covered by the plurality of PTC thermistors when a plurality of PTC thermistors are installed.

When the PTC thermistor 122 is arranged so as to cover the inner peripheral side wall 117 of the hollow honeycomb structure portion, the inner electrode portion 120b of the PTC thermistor 122 comes into direct contact with the inner peripheral side wall 117 of the hollow honeycomb structure portion. It is preferable that they are arranged so that there are no portions. Similarly, when the PTC thermistor 122 is arranged so as to cover the outer peripheral side wall 112 of the hollow honeycomb structure portion, the outer electrode portion 120a of the PTC thermistor 122 is in direct contact with the outer peripheral side wall 112 of the hollow honeycomb structure portion. It is preferable that the arrangement is made so that there is no portion to be formed. According to this configuration, when the PTC thermistor is operated, the current path can be completely cut off, so that the effect of enhancing the overheat prevention performance can be obtained.

Since the material, Curie point, and average thickness of the PTC thermistor 122 in the second embodiment are the same as those in the PTC thermistor described in the first embodiment, detailed description thereof will be omitted.

(2. How to use the heater element)
The heater element according to the present invention can generate heat by applying a voltage between a pair of electrodes, for example. As the applied voltage, from the viewpoint of rapid heating, it is preferable to apply a voltage of 200 V or more, and it is more preferable to apply a voltage of 250 V or more. As described above, the heater element according to the present invention is highly safe because it can suppress the initial current even when a high voltage is applied. In addition, since the safety specifications do not become heavy, the equipment around the heater can be manufactured at low cost.

When the heater element is generating heat by applying a voltage, the gas can be heated by flowing the gas through the cell. The temperature of the gas flowing into the cell can be, for example, −60 ° C. to 20 ° C., and typically −10 ° C. to 20 ° C.

(3. Manufacturing method of heater element)
Next, a method for manufacturing the heater element according to the present invention will be exemplified.

(3.1 Fabrication of honeycomb structure)
The columnar honeycomb structure portion (including the hollow honeycomb structure portion) can be manufactured according to a known method for manufacturing a honeycomb structure. For example, first, a metal silicon powder (metal silicon), a binder, a surfactant, a pore-forming material, water, or the like is added to silicon carbide powder (silicon carbide) to prepare a molding raw material. It is preferable that the mass of the metallic silicon is 10 to 40% by mass with respect to the total of the mass of the silicon carbide powder and the mass of the metallic silicon. It should be noted that this is a blending of molding raw materials when the material of the honeycomb structure portion is Si-bonded SiC, and when the material of the honeycomb structure portion is SiC, metallic silicon is not added.

Examples of the binder include methyl cellulose, hydroxypropyl methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol and the like. Among these, it is preferable to use methyl cellulose and hydroxypropoxyl cellulose in combination. The binder content is preferably 2.0 to 10.0 parts by mass when the total mass of the silicon carbide powder and the metallic silicon powder is 100 parts by mass.

The water content is preferably 20 to 60 parts by mass when the total mass of the silicon carbide powder and the metallic silicon powder is 100 parts by mass.

As the surfactant, ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be used. These may be used individually by 1 type, or may be used in combination of 2 or more types. The content of the surfactant is preferably 0.1 to 2.0 parts by mass when the total mass of the silicon carbide powder and the metallic silicon powder is 100 parts by mass.

The pore-forming material is not particularly limited as long as it becomes pores after firing, and examples thereof include graphite, starch, foamed resin, water-absorbent resin, silica gel, and the like. The content of the pore-forming material is preferably 0.5 to 10.0 parts by mass when the total mass of the silicon carbide powder and the metallic silicon powder is 100 parts by mass.

Next, the obtained molding raw materials are kneaded to form a clay, and then the clay is extruded to produce a honeycomb molded body. In extrusion molding, a base having a desired overall shape, cell shape, partition wall thickness, cell density and the like can be used.

Then, the obtained honeycomb molded body is dried. In the drying step, conventionally known drying methods such as hot air drying, microwave drying, dielectric drying, vacuum drying, vacuum drying, and freeze drying can be used. Among them, a drying method combining hot air drying and microwave drying or dielectric drying is preferable in that the entire molded product can be dried quickly and uniformly.

Next, the columnar honeycomb structure can be produced by firing the dried honeycomb molded body. A degreasing step to remove the binder can also be performed before firing. The firing conditions can be appropriately determined depending on the material of the honeycomb molded body. For example, when the material of the columnar honeycomb structure is mainly composed of Si-bonded SiC, the columnar honeycomb is formed by firing the honeycomb molded body in an inert gas atmosphere such as Ar under the condition that the Si metal is bonded between the SiC particles. The structural part can be manufactured.

The firing furnace is not particularly limited, but an electric furnace, a gas furnace, or the like can be used.

(3.2 Preparation of PTC thermistor)
The PTC thermistor can be manufactured, for example, by the following procedure. A raw material composition containing a dispersion medium and a binder is mixed with the ceramic raw material and kneaded to prepare a paste or slurry. Additives such as a dispersant, a semiconductor agent, a shifter, a metal oxide, a property improving agent, and a conductor powder can be added to the raw material composition, if necessary.

The ceramic raw material remains after firing and is a raw material for the portion constituting the skeleton of the PTC thermistor as ceramics. The ceramic raw material can be provided, for example, in the form of powder. As the ceramic raw material, oxides and carbonate raw materials such as TiO ₂ and BaCO ₃ , which are the main components of barium titanate, can be used. Also, semiconductor agents such as Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, and low temperature shifters such as Sr, Sn and Zr. , (Bi-Na), (Bi-K) and other high temperature shifters, Mn and other property improvers, even if oxides, carbonates, or oxalates that become oxides after firing are used. good. Conductor powders such as carbon black and nickel may be added to control conductivity.

Examples of the dispersion medium include water or a mixed solvent of water and an organic solvent such as alcohol, and water can be particularly preferably used.

Examples of the binder include organic binders such as methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and polyvinyl alcohol. In particular, it is preferable to use methyl cellulose and hydroxypropoxyl cellulose in combination. Further, from the viewpoint of maintaining the strength of the molded product, the binder content is preferably 4 parts by mass or more, more preferably 5 parts by mass or more, and 6 parts by mass with respect to 100 parts by mass of the ceramic raw material. The above is even more preferable. The binder content is preferably 9 parts by mass or less, more preferably 8 parts by mass or less, and 7 by mass with respect to 100 parts by mass of the ceramic raw material, from the viewpoint of suppressing cracking of the molded product during binder removal heating. It is even more preferably less than or equal to parts by mass. The binder may be one that uses one type alone or one that uses two or more types in combination.

As the dispersant, a surfactant such as ethylene glycol, dextrin, fatty acid soap, or polyalcohol can be used. The dispersant may be used alone or in combination of two or more. The content of the dispersant is preferably 0 to 2 parts by mass with respect to 100 parts by mass of the ceramic raw material.

Next, the obtained paste or slurry is applied to desired locations on the outer peripheral side wall and / or the inner peripheral side wall of the honeycomb structure, and then the paste or slurry is fired. Prior to firing, temporary firing may be performed to remove the binder and the like. As the firing conditions, it is preferable to heat at 950 to 1300 ° C. for 10 to 120 minutes in an inert atmosphere such as nitrogen, argon or vacuum.

Alternatively, the PTC thermistor may be produced by kneading the raw material composition described above to obtain clay, forming it into a desired PTC thermistor shape, and then drying, degreasing and firing. The firing conditions can be appropriately determined depending on the material of the PTC thermistor. For example, when the material of the PTC thermistor contains barium titanate as a main component, the firing temperature is preferably 1100 to 1400 ° C, more preferably 1200 to 1300 ° C. The firing time is preferably about 1 to 4 hours. The produced PTC thermistor can be bonded to a desired location on the outer peripheral side wall and / or the inner peripheral side wall of the honeycomb structure by a method such as metallizing bonding (brazing), diffusion bonding, or an inorganic adhesive.

(3.3 Formation of electrode part)
An electrode portion can be joined to the honeycomb structure portion with a PTC thermistor thus obtained. The electrode portion can be formed on the surface of the PTC thermistor by a metal precipitation method such as sputtering, vapor deposition, electrolytic precipitation, or chemical precipitation. Further, the electrode portion can also be formed by applying the electrode paste on the surface of the PTC thermistor and then baking the electrode portion. Furthermore, it can also be formed by thermal spraying. By either method, the electrode portion coated on the surface of the PTC thermistor can be formed. The electrode portion may be composed of a single layer, but may also be composed of a plurality of electrode layers having different compositions. For example, the thickness of the electrode portion is about 5 to 30 μm for baking paste, about 100 to 1000 nm for dry plating such as sputtering and vapor deposition, about 10 to 100 μm for thermal spraying, and 5 for wet plating such as electrolytic precipitation and chemical precipitation. It is preferably about 30 μm. The inner electrode portion can also be provided so as to completely close the hollow portion of the honeycomb structure portion, whereby the structural strength of the heater element can be increased.

(4. Heater for heating the passenger compartment)
FIG. 3 schematically shows the configuration of the vehicle interior heating heater 300 according to the embodiment of the present invention. The heater according to the present embodiment is an inflow pipe 132 (132a, 132b) that communicates the heater element 100 (or 200) according to the present invention, the outside air or the air inside the vehicle interior 130, and the bottom surface 114 of one of the heater elements 100 (or 200). ), A battery 134 for applying a voltage to the heater element 100 (or 200), and an outflow pipe 136 for communicating the air in the passenger compartment 130 with the other bottom surface 116 of the heater element 100 (or 200).

The heater element 100 (or 200) can be configured to energize and generate heat by connecting to the battery 134 with an electric wire 119 and turning on the power switch in the middle of the connection, for example. be.

A blower 138 can be installed on the upstream side or the downstream side of the heater element 100 (or 200). The blower is preferably installed on the downstream side of the heater element 100 (or 200) from the viewpoint of arranging the high voltage parts as far away from the passenger compartment as possible to ensure safety. When the blower 138 is driven, air flows into the heater element 100 (or 200) from the inside or outside of the vehicle through the inflow pipes 132 (132a, 132b). The air is heated while passing through the heating element 100 (or 200) during heat generation. The heated air flows out from the heater element 100 (or 200) and is sent into the vehicle interior through the outflow pipe 136. The outflow pipe outlet may be placed near the occupant's feet so that the heating effect is particularly high even in the passenger compartment, or the pipe outlet may be placed inside the seat to warm the seat from the inside, or the window. It may be arranged in the vicinity to have the effect of suppressing fogging of the window.

The vehicle interior heating heater 300 according to the embodiment of FIG. 3 includes an inflow pipe 132a that communicates the outside air with the bottom surface 114 of one of the heater elements 100 (or 200). Further, the vehicle interior heating heater according to the embodiment of FIG. 3 includes an inflow pipe 132b that communicates the air inside the vehicle interior 130 with the bottom surface 114 of one of the heater elements 100 (or 200). The inflow pipe 132a and the inflow pipe 132b merge in the middle. Valves 139 (139a and 139b) can be installed in the inflow pipe 132a and the inflow pipe 132b on the upstream side of the confluence. By controlling the opening and closing of the valve 139 (139a, 139b), between the mode in which the outside air is introduced into the heater element 100 (or 200) and the mode in which the air inside the passenger compartment 130 is introduced into the heater element 100 (or 200). You can switch. For example, when the valve 139a is opened and the valve 139b is closed, the mode is set in which the outside air is introduced into the heater element 100 (or 200). It is also possible to open both the valve 139a and the valve 139b to simultaneously introduce the outside air and the air inside the passenger compartment 130 into the heater element 100 (or 200).

The heater of the present invention can be used as an auxiliary heater for a vehicle that employs a steam compression heat pump as a main heating device, and in that case, it is assumed that air is not directly blown to the vehicle interior as described above. In that case, the "vehicle compartment" described above may be installed in a form of replacing "a part of the ventilation pipe of the main heating device". Further, the return pipe from the passenger compartment may be further branched to provide a path for exhausting to the outside of the vehicle via a valve, but the exhaust to the outside of the vehicle is performed by the main heating device using a steam compression heat pump. It may be done in conjunction with another exhaust system.

Hereinafter, examples for better understanding the present invention and its advantages will be given, but the present invention is not limited to the examples.

<Examples 1 to 6>
(1. Fabrication of honeycomb structure)
A rectangular parallelepiped Si-bonded SiC honeycomb structure having the dimensions shown in Table 1 was produced by molding and firing by a known method. In all the examples, the material composition of the honeycomb structure is the same. The average thickness of the partition wall of the honeycomb structure was 0.13 mm, the cell density was 60 cells / cm ² , the cell shape in the cross section orthogonal to the cell flow path was square, and the aperture ratio was 0.806. In Table 1, a and b indicate the length of each base of the honeycomb structure, and c indicates the height of the honeycomb structure (the length of the flow path of the cell). In Table 1, V indicates the volume of the honeycomb structure portion, and TS indicates the total area of the outer peripheral side wall.

(2. Formation of PTC thermistor)
A paste in which a dispersion medium, a binder, a shifter, etc. are mixed with TiO ₂ and BaCO ₃ , which are raw materials for barium titanate, is prepared, applied to a predetermined position on the outer peripheral side wall of the honeycomb structure, and then fired. Then, a pair of PTC thermistors of various specifications shown in Table 1 were formed so as to face the outer peripheral side wall of the honeycomb structure portion according to the numbers of the examples. In Examples 5 and 6, the PTC thermistor was formed after forming an electrically insulating layer (silicon oxide film) on a part of the outer peripheral side wall of the honeycomb structure to be covered by the PTC thermistor by the CVD method.

In Table 1, the covering area S indicates the total area in which the outer peripheral side wall is covered by the PTC thermistor. In Table 1, the Curie point indicates the Curie point measured by the method described above for a sample having the same specifications as the PTC thermistor used in the example. In Table 1, S / V indicates the ratio of the total area S of the portion covered with the outer peripheral side wall of the honeycomb structure portion by the PTC thermistor to the volume V of the honeycomb structure portion. In Table 1, the electric conduction area is the area Se obtained by subtracting the area of the portion where the outer peripheral side wall of the honeycomb structure portion is in contact with the electric insulating layer from the total area S of the portion where the outer peripheral side wall of the honeycomb structure portion is covered with the PTC thermistor. show. Except for Examples 5 and 6, the electric conduction area is equal to the covering area S. In Table 1, the covering position shows the covering position of the outer peripheral side wall by the PTC thermistor and the electrically insulating layer when the honeycomb structure portion is observed from the bottom surface side. In any of the embodiments, the PTC thermistor was extended over the entire height direction of the honeycomb structure.

(3. Formation of electrode part)
An electrode portion (thickness 1 mm) made of tungsten was formed on the surface of the PTC thermistor of the honeycomb structure portion with the PTC thermistor prepared as described above by baking a glass frit mixed paste to manufacture a heater element. .. In each of the examples, the electrode portion was formed so as to cover the entire surface of the PTC thermistor without excess or deficiency, but care was taken not to have a portion that directly contacts the outer peripheral side wall of the honeycomb structure portion. In Table 1, when the electrode portion is "outside" in Examples 1 to 6, it means that the electrode portion is on the outer peripheral side of the PTC thermistor.

(4. Test of effect of preventing overheating)
Honeycomb height (length of cell flow path) when a voltage of 200 V is applied at room temperature to heat the pair of facing electrode portions of the heater element according to each of the above procedures. The maximum temperature reached near the honeycomb center axis at the center position in the direction was investigated. Then, the effect of preventing overheating was evaluated according to the following criteria. The results are shown in Table 1.
D: Curie temperature of PTC material + 100 ° C or higher.
C: Curie point temperature of PTC material + 80 ° C or higher and lower than + 100 ° C.
B: Curie point temperature of PTC material + 60 ° C or higher and lower than + 80 ° C.
A: Curie point temperature of PTC material is less than + 60 ° C.

(5. Honeycomb temperature uniformity survey)
Each position of the honeycomb when heated by applying a voltage of 200 V at room temperature to the pair of opposite electrode portions of the heater element according to each embodiment obtained in the above procedure: Honeycomb height (of the cell). Within the central plane in the (length of flow path) direction, on a line connecting the center of one side with five points on one diagonal line (two points on the outermost cell, two points on the center cell, and two points in the middle cell). The temperature distribution of 5 points (2 points of the outermost cell, 1 point of the central cell, and 2 points of the intermediate cell (however, the central cell is common)) was investigated by a method of temperature measurement using a thermocouple. Then, the honeycomb temperature uniformity was evaluated according to the following criteria. The results are shown in Table 1.
D: Maximum temperature difference in the honeycomb 100 ° C or more C: Maximum temperature difference in the honeycomb 60 ° C or more and less than 100 ° C B: Maximum temperature difference in the honeycomb 30 ° C or more and less than 60 ° C A: Maximum temperature difference in the honeycomb less than 30 ° C

(6. Consideration)
As can be seen from the results in Table 1, it can be seen that the effect of preventing overheating improves as the S / V increases. Further, it can be seen that the honeycomb temperature uniformity is improved by electrically insulating and covering the region where the length of the electric conduction path in the honeycomb is relatively short.

<Comparative Example 1>
The same honeycomb structure as in Example 1 was prepared. In Comparative Example 1, a heater element was produced in the same manner as in Example 1 except that the electrode portion was formed on the outer peripheral side wall of the honeycomb structure portion and then the PTC thermistor was formed. In Table 1, when the electrode portion is "inside" in Comparative Example 1, it means that the electrode portion is on the inner peripheral side of the PTC thermistor. The obtained heater element was tested for the effect of preventing overheating and the honeycomb temperature uniformity was investigated by the same method as in the examples. The results are shown in Table 1.

In Comparative Example 1, the heat from the honeycomb structure portion was transferred to the PTC thermistor via the electrode portion, so that the response speed was slowed down. As a result, the effect of preventing overheating was reduced as compared with Example 1.

100, 200 Heater element 112 Outer side wall 113 Barrier 114 One bottom surface 115 Cell 116 Inner bottom side wall 118 Electrical insulation layer 119 Electric wire 120 Electrode part 120a Outer electrode part 120b Inner electrode part 122 PTC thermista 130 Vehicle room 139 (139a) 139b) Valve 132 (132a, 132b) Inflow pipe 134 Battery 136 Outflow pipe 138 Blower 300 Heater for heating the cabin

Claims (19)

It is a heater element for heating the passenger compartment of a vehicle.
A columnar honeycomb structure capable of energizing and generating heat, having an outer peripheral side wall and a partition wall arranged on the inner peripheral side of the outer peripheral side wall and forming a plurality of cells forming a fluid flow path from one bottom surface to the other bottom surface.
A pair of electrode portions formed so as to face the outer peripheral side of the outer peripheral side wall of the columnar honeycomb structure portion, and
A PTC thermistor arranged so as to cover the outer peripheral side wall of the columnar honeycomb structure portion at a position sandwiched between the outer peripheral side wall of the columnar honeycomb structure portion and at least one electrode portion of the pair of electrode portions.
A heater element for heating the passenger compartment. The ratio (S / V) of the total area S of the portion covered with the outer peripheral side wall of the columnar honeycomb structure by the PTC thermistor to the volume V of the columnar honeycomb structure is 0.1 cm ² / cm ³ or more. The heater element for heating the passenger compartment according to claim 1. The heater element for heating a vehicle interior according to claim 2, wherein the S / V is 0.2 cm ² / cm ³ or more. The heater element for heating a vehicle interior according to any one of claims 1 to 3, wherein the plurality of cells are arranged radially in a cross section in a direction orthogonal to the flow path of the fluid of the plurality of cells. The heater element for heating a vehicle interior according to any one of claims 1 to 4, wherein the PTC thermistor is made of a PTC material having a Curie point of 100 ° C. or higher and 250 ° C. or lower. The heater element for heating a vehicle interior according to any one of claims 1 to 5, wherein the columnar honeycomb structure portion contains Si-bonded SiC. The vehicle interior heating according to any one of claims 1 to 6, wherein the PTC thermistor is arranged so that at least one of the electrode portions does not come into direct contact with the outer peripheral side wall of the columnar honeycomb structure portion. Heater element. A PTC thermistor is disposed at a position sandwiched between the outer peripheral side wall of the columnar honeycomb structure portion and each electrode portion of the pair of electrode portions.
An electrically insulating layer located between a part of at least one PTC thermistor and the outer peripheral side wall of the columnar honeycomb structure portion, and the current distribution in the honeycomb structure portion when a voltage is applied to the pair of electrode portions. The heater element for heating a vehicle interior according to any one of claims 1 to 7, further comprising an electrically insulating layer extended at a position capable of enhancing uniformity. The total area S of the portion where the outer peripheral side wall is covered with the PTC thermistor and the area Se obtained by subtracting the area of the portion where the outer peripheral side wall is in contact with the electrical insulating layer from the total area S are 0.3 ≦ Se / S <. The heater element according to claim 8, which satisfies 1. It is a heater element for heating the passenger compartment of a vehicle.
Energization having an outer peripheral side wall, an inner peripheral side wall, and a partition wall disposed between the outer peripheral side wall and the inner peripheral side wall and partitioning a plurality of cells forming a fluid flow path from one bottom surface to the other bottom surface. Hollow honeycomb structure that can generate heat,
The outer electrode portion formed on the outer peripheral side of the outer peripheral side wall of the hollow honeycomb structure portion,
The inner electrode portion formed on the inner peripheral side of the inner peripheral side wall of the hollow honeycomb structure portion,
as well as,
It is arranged so as to cover the inner peripheral side wall of the hollow honeycomb structure portion at a position sandwiched between the inner peripheral side wall of the hollow honeycomb structure portion and the inner electrode portion, and / or. A PTC thermista, which is arranged so as to cover the outer peripheral side wall of the hollow honeycomb structure portion at a position sandwiched between the outer peripheral side wall of the hollow honeycomb structure portion and the outer electrode portion.
A heater element for heating the passenger compartment. The ratio (S / V) of the total area S of the portion covered with the inner peripheral side wall and / or the outer peripheral side wall of the hollow honeycomb structure portion by the PTC thermistor with respect to the volume V of the hollow honeycomb structure portion is 0. The heater element for heating a vehicle interior according to claim 10, which is 1 cm ² / cm ³ or more. The heater element for heating a vehicle interior according to claim 11, wherein the S / V is 0.2 cm ² / cm ³ or more. The heater element for heating a vehicle interior according to any one of claims 10 to 12, wherein the plurality of cells are arranged radially in a cross section in a direction orthogonal to the flow path of the fluid of the plurality of cells. The heater element for heating a vehicle interior according to any one of claims 10 to 13, wherein the PTC thermistor is made of a PTC material having a Curie point of 100 ° C. or higher and 250 ° C. or lower. The heater element for heating a vehicle interior according to any one of claims 10 to 14, wherein the hollow honeycomb structure portion contains Si-bonded SiC. When the PTC thermistor is arranged so as to cover the inner peripheral side wall of the hollow honeycomb structure portion, the PTC thermistor has a portion where the inner electrode portion directly contacts the inner peripheral side wall of the hollow honeycomb structure portion. When the PTC thermistor is arranged so as not to cover the outer peripheral side wall of the hollow honeycomb structure portion, the outer electrode portion of the PTC thermistor is arranged with the outer peripheral side wall of the hollow honeycomb structure portion. The heater element for heating a passenger compartment according to any one of claims 10 to 15, which is arranged so that there is no portion that comes into direct contact with the heater element. The method for using a heater element according to any one of claims 1 to 16, wherein a voltage of 200 V or more is applied between two electrodes. 17. The method of using a heater element according to claim 17, wherein a gas of -60 ° C to 20 ° C passes through the cell. The heater element according to any one of claims 1 to 16.
An inflow pipe that communicates the outside air or vehicle interior air with the bottom surface of one of the heater elements,
A battery for applying a voltage to the heater element, and an outflow pipe that communicates the other bottom surface of the heater element with the passenger compartment.
A heater for heating the passenger compartment.

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