Vehicle air-conditioning system and electric vehicle

Abstract

To provide an air conditioning system for a vehicle capable of improving a cruising distance of an electric vehicle by saving battery consumption without hindering comfortable driving.SOLUTION: A vehicle air-conditioning system includes an air-conditioning duct 10 through which air from a vehicle interior and / or a vehicle exterior can flow, a ventilator 20, a honeycomb structure disposed inside an outer peripheral wall and having partition walls that define a plurality of cells serving as air flow paths extending from a first end face to a second end face, and a hygroscopic layer provided on surfaces of the partition walls. The air conditioner includes a humidity control device 30 arranged in an air-conditioning duct 10 on the downstream side of a ventilator 20 and a control part 40 for controlling the ventilator 20, and when the electric resistance ratio of the electric resistance at the end of energization to the electric resistance at the start of energization of the humidity control device 30 deviates from a predetermined range in the regeneration mode of the humidity control device 30, the control part 40 controls at least one selected from the energization time and the applied voltage to the humidity control device 30 and the number of revolutions of the ventilator 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vehicle air conditioning system and an electric vehicle. [Background technology]

[0002] There is a growing demand for improved cabin environments in automobiles and other vehicles. Specific examples of such demands include humidity control within the vehicle cabin. Ventilation is an effective solution to meet these demands, but ventilation can significantly reduce heating energy in winter, resulting in reduced energy efficiency. This energy loss, particularly in battery electric vehicles (BEVs), poses a significant problem of reduced driving range.

[0003] As a method for solving the above problems, Patent Document 1 proposes a vehicle air conditioning system (vehicle interior purification system) that includes a honeycomb structure having an outer peripheral wall and partition walls disposed inside the outer peripheral wall that define a plurality of cells that form flow paths extending from a first end face to a second end face, where at least the partition walls are made of a material having PTC properties, and a humidity control device (heater element) that includes a functional material-containing layer provided on the surface of the partition wall. This vehicle air conditioning system can dehumidify the air in the vehicle interior by capturing moisture (water vapor) contained in the air from the vehicle interior in the functional material-containing layer and returning it to the vehicle interior, and can regenerate the functional material-containing layer by heating the moisture captured in the functional material-containing layer to cause it to react or desorb and be released outside the vehicle.

[0004] Saving battery power (electricity cost) is important to improve the driving range of electric vehicles. In particular, reducing the power consumption of vehicle air conditioning systems is an urgent issue. In particular, the consumption of heating energy when driving in cold climates is a major cause of reduced driving range. In conventional electric vehicles equipped with a vehicle air conditioning system, it is known to control power loss by using a temperature sensor to detect an abnormality in the PTC heater built into the vehicle air conditioning system and cutting off the power supply (Patent Document 2), or by monitoring the electrical state of the PTC heater and notifying the driver of an abnormality in the heat storage device (Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-47123 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-203254 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-137623 Summary of the Invention [Problem to be solved by the invention]

[0006] However, taking measures after an abnormality has occurred cannot be considered true energy conservation. Shutting down or replacing a vehicle air conditioning system when an abnormality occurs disrupts comfortable driving, and is something that should be avoided even before the issue of saving electricity costs.

[0007] The present invention has been made to solve the above-mentioned problems, and aims to provide a vehicle air conditioning system that can save battery power and improve the cruising range of an electric vehicle without hindering comfortable driving. Another object of the present invention is to provide an electric vehicle that can save battery power consumption in a vehicle air conditioning system and improve cruising range without impeding comfortable driving. [Means for solving the problem]

[0008] As a result of extensive research into vehicle air conditioning systems equipped with a humidity control device, the inventors discovered that by monitoring the electrical resistance of the humidity control device when the humidity control device is in a regeneration mode, calculating the electrical resistance ratio of the electrical resistance at the end of current flow to the electrical resistance at the start of current flow, and performing predetermined control when the electrical resistance ratio deviates from a predetermined range, it is possible to predict an abnormality in the humidity control device and save battery power, which led to the completion of the present invention. That is, the present invention is exemplified as follows.

[0009] <1> an air conditioning duct through which air from the vehicle interior and / or outside the vehicle can circulate; a fan disposed in the air conditioning duct; a honeycomb structure having an outer peripheral wall, and partition walls disposed inside the outer peripheral wall and defining a plurality of cells that serve as the air flow path extending from a first end face to a second end face; and a humidity control device having a moisture absorption layer provided on a surface of the partition wall, the humidity control device being disposed in the air conditioning duct downstream of the fan; a control unit that controls the humidity control device and the ventilator; A vehicle air conditioning system comprising: the control unit, when in a regeneration mode for the humidity control device, monitors the electrical resistance of the humidity control device and calculates an electrical resistance ratio of the electrical resistance at the end of current application to the electrical resistance at the start of current application; When the electrical resistance ratio deviates from a predetermined range, the control unit controls at least one selected from the power supply time and input voltage to the humidity control device, and the rotation speed of the fan.

[0010] <2> When the electrical resistance ratio becomes smaller than a predetermined range, the control unit performs at least one selected from extending the energization time, increasing the applied voltage, and decreasing the rotation speed. <1> The vehicle air conditioning system according to claim 1.

[0011] <3> When the electrical resistance ratio becomes larger than a predetermined range, the control unit executes at least one selected from the group consisting of shortening the energization time, lowering the applied voltage, and increasing the rotation speed. <1> The vehicle air conditioning system according to claim 1.

[0012] <4> The predetermined range of the electrical resistance ratio is 1.1 to 2.5. <1> ~ <3> 10. A vehicle air conditioning system according to claim 9, wherein:

[0013] <5> the air conditioning duct is branched downstream of the fan into a first flow path in which the humidity control device is disposed and a second flow path in which the humidity control device is not disposed, a first valve capable of adjusting the amount of air that flows into the first flow path upstream of the humidity control device, and a second valve capable of adjusting the amount of air that flows into the second flow path; the first valve and the second valve are controlled by the control unit, the control unit closes the first valve when the electrical resistance ratio falls outside a predetermined range. <1> ~ <4> 10. A vehicle air conditioning system according to claim 9, wherein:

[0014] <6> The control unit stops the supply of electricity to the humidity control device when the electrical resistance ratio deviates from a predetermined range. <1> , <3> and <4> 10. A vehicle air conditioning system according to claim 9, wherein:

[0015] <7> a third valve arranged upstream of the fan and capable of adjusting the inflow rate of the air from the vehicle compartment and the air from outside the vehicle; When the electrical resistance ratio deviates from a predetermined range, the control unit controls the third valve to increase the amount of air flowing in from outside the vehicle, thereby adjusting the humidity in the vehicle compartment. <5> or <6> The vehicle air conditioning system according to claim 1.

[0016] <8> A humidity sensor is installed inside the vehicle. The control unit controls the third valve based on the humidity measured by the humidity sensor. <7> The vehicle air conditioning system according to claim 1.

[0017] <9> The control unit notifies an abnormality in the vehicle cabin when the electrical resistance ratio deviates from a predetermined range. <1> ~ <8> 10. A vehicle air conditioning system according to claim 9, wherein:

[0018] <10> In the honeycomb structure, at least the partition walls are made of a material having PTC properties. <1> ~ <9> 10. A vehicle air conditioning system according to claim 9, wherein:

[0019] <11> The humidity control device further includes a pair of electrodes provided on the first end face and the second end face of the honeycomb structure, or on the outer peripheral wall of the honeycomb structure that is parallel to the cell extension direction. <1> ~ <10> 10. A vehicle air conditioning system according to claim 9, wherein:

[0020] <12> <1> ~ <11> 10. An electric vehicle equipped with the vehicle air conditioning system according to claim 9. [Effects of the Invention]

[0021] According to the present invention, it is possible to provide a vehicle air conditioning system that can save battery power and improve the cruising range of an electric vehicle without impeding comfortable driving. Furthermore, according to the present invention, it is possible to provide an electric vehicle that can save battery power consumption in a vehicle air conditioning system and increase the cruising range without impeding comfortable driving. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic diagram illustrating the overall configuration of a vehicle air conditioning system according to a first embodiment of the present invention. [Figure 2A] 1 is a schematic diagram of a cross section parallel to the flow path direction of a humidity control device used in a vehicle air conditioning system according to a first embodiment of the present invention. [Figure 2B] 2B is a schematic cross-sectional view of the humidity control device of FIG. 2A taken along line aa'. FIG. [Figure 3]FIG. 1 is a schematic diagram illustrating the overall configuration of a vehicle air conditioning system according to a second embodiment of the present invention. [Figure 4] FIG. 10 is a schematic diagram illustrating the overall configuration of a vehicle air conditioning system according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] The vehicle air conditioning system of the present invention includes an air conditioning duct through which air from the vehicle interior and / or outside the vehicle can flow; a fan disposed within the air conditioning duct; a honeycomb structure having an outer peripheral wall and partition walls disposed inside the outer peripheral wall and defining a plurality of cells that serve as air flow paths extending from a first end face to a second end face, and a humidity control device disposed within the air conditioning duct downstream of the fan, the humidity control device having a moisture absorptive layer on the surface of the partition wall; and a control unit for controlling the humidity control device and the fan. The control unit monitors the electrical resistance of the humidity control device during a regeneration mode of the humidity control device and calculates the ratio of the electrical resistance at the end of current application to the electrical resistance at the start of current application. If the electrical resistance ratio falls outside a predetermined range, the control unit controls at least one selected from the power application time and voltage of the humidity control device and the rotational speed of the fan. The vehicle air conditioning system of the present invention having such a configuration can predict an abnormality in the humidity control device and conserve battery power, thereby improving the range of an electric vehicle without impeding comfortable driving.

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, and it should be understood that modifications and improvements made to the following embodiments based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention are also within the scope of the present invention.

[0025] <Embodiment 1> The vehicle air conditioning system according to the first embodiment of the present invention can be suitably used in various vehicles such as automobiles. Examples of vehicles include, but are not limited to, automobiles and trains. Examples of automobiles include, but are not limited to, gasoline-powered vehicles, diesel-powered vehicles, gas-fueled vehicles using CNG (compressed natural gas) or LNG (liquefied natural gas), fuel cell vehicles, electric vehicles, and plug-in hybrid vehicles. The vehicle air conditioning system according to the first embodiment of the present invention can be suitably used in particular in vehicles without internal combustion engines, such as electric vehicles and trains.

[0026] Fig. 1 is a schematic diagram of the overall configuration of a vehicle air conditioning system according to embodiment 1 of the present invention. Fig. 2A is a schematic diagram of a cross section parallel to the flow path direction of a humidity control device used in the vehicle air conditioning system according to embodiment 1 of the present invention. Fig. 2B is a schematic diagram of a cross section taken along line a-a' in the humidity control device of Fig. 2A.

[0027] As shown in FIG. 1, the vehicle air conditioning system according to the first embodiment of the present invention includes an air conditioning duct 10, a ventilator 20, a humidity control device 30, and a control unit .

[0028] Air from the vehicle compartment or outside the vehicle can flow through the air conditioning duct 10. The air conditioning duct 10 branches downstream of the humidity control device 30 into a flow path 11 that introduces air into the vehicle compartment and a flow path 12 that discharges air outside the vehicle. If necessary, known components (not shown) used for heating and cooling, such as an evaporator or a condenser, may be disposed in the flow path 11 that introduces air into the vehicle compartment. In this specification, the terms "upstream side" and "downstream side" are based on the flow of air circulating through the vehicle air conditioning system.

[0029] A valve 51 is disposed at a branch point between the flow path 11 for introducing air into the vehicle cabin and the flow path 12 for discharging air to the outside of the vehicle. The valve 51 is capable of switching the air flow between the flow path 11 for introducing air into the vehicle cabin and the flow path 12 for discharging air to the outside of the vehicle. The valve 51 is not particularly limited as long as it has the above-described function, and any known valve can be used. Specifically, the valve 51 may be electrically driven and have the function of switching between the flow paths 11 and 12, and a solenoid valve, an electric valve, or the like can be used. For example, the valve 51 includes an opening / closing door supported on a rotating shaft and an actuator such as a motor that rotates the rotating shaft. The actuator can be configured to be controllable by the control unit 40.

[0030] The ventilator 20 is disposed inside the air conditioning duct 10. The ventilator 20 may be disposed upstream of the humidity control device 30, or may be disposed downstream of the humidity control device 30.

[0031] The humidity control device 30 is disposed inside the air conditioning duct 10 downstream of the fan 20. The number of humidity control devices 30 disposed inside the air conditioning duct 10 may be one or more. When a plurality of humidity control devices 30 are provided, they may be disposed in parallel or in series with respect to the flow of air circulating inside the air conditioning duct 10. 2A and 2B, the humidity control device 30 includes a honeycomb structure 31 having an outer peripheral wall 32 and partition walls 35 disposed inside the outer peripheral wall 32 to define a plurality of cells 34 that serve as air flow paths extending from a first end face 33a to a second end face 33b, and a moisture absorbing layer 36 provided on the surface of the partition wall 35. The honeycomb structure 31 may also be provided with a pair of electrodes 37a, 37b and terminals 38 connected to the pair of electrodes 37a, 37b.

[0032] The control unit 40 can control the humidity control device 30 and the ventilator 20. The control unit 40 can also control the valve 51. Specifically, the control unit 40 is electrically connected to the humidity control device 30, the ventilator 20, and the valve 51, and can control the ventilator 20, the humidity control device 30, and each valve according to instructions from the control unit 40. In particular, the ventilator 20 can control the flow rate of air flowing through the air conditioning duct 10 by controlling the rotation speed of the ventilator 20 according to instructions from the control unit 40.

[0033] In a vehicle air conditioning system having the above-described structure, air is circulated through the air conditioning duct 10, the moisture content in the air is reduced in the humidity control device 30, and the air is then circulated through the flow path 11, thereby dehumidifying the air inside the vehicle cabin. The mode of the humidity control device 30 in this case is called the "moisture absorption mode." Furthermore, the humidity control device 30 can be regenerated by heating the humidity control device 30 while circulating air through the air conditioning duct 10 to desorb the moisture adsorbed by the humidity control device 30, and then flowing the air containing the moisture into the flow path 12 and discharging it outside the vehicle. The mode of the humidity control device 30 in this case is called the "regeneration mode." The moisture absorption mode and the regeneration mode are repeatedly performed depending on the vehicle interior environment.

[0034] When the humidity control device 30 is in a regeneration mode, the control unit 40 monitors the electrical resistance of the humidity control device 30 (specifically, the honeycomb structure 31) and calculates the electrical resistance ratio of the electrical resistance at the end of current application to the electrical resistance at the start of current application. If the electrical resistance ratio deviates from a predetermined range, the control unit 40 controls at least one selected from the duration of current application to the humidity control device 30, the input voltage, and the rotation speed of the fan 20. By controlling in this manner, an abnormality in the humidity control device 30 can be predicted and battery consumption associated with the abnormality in the humidity control device 30 can be reduced. As a result, battery consumption can be reduced and the cruising range of the electric vehicle can be improved without impeding comfortable driving. Note that abnormalities in the humidity control device 30 include not only a malfunction of the humidity control device 30 but also performance degradation associated with use of the humidity control device 30.

[0035] Here, if the electrical resistance ratio of the humidity control device 30 is within a predetermined range, it can be said that the regeneration mode of the humidity control device 30 is being executed appropriately without excessive battery consumption. The predetermined range of the electrical resistance ratio is not particularly limited and can be set depending on the humidity control device 30 being used, but is typically 1.1 to 2.5, preferably 1.2 to 2.3, and more preferably 1.3 to 2.2. Setting the predetermined range of the electrical resistance ratio within this range allows for early detection of an abnormality in the humidity control device 30, thereby preventing damage to the humidity control device 30 and making it easier to save battery consumption associated with an abnormality in the humidity control device 30.

[0036] Specifically, when the electrical resistance ratio of the humidity control device 30 falls below a predetermined range, the control unit 40 performs at least one of the following actions: extending the time for which electricity is applied to the humidity control device 30; increasing the voltage applied to the humidity control device 30; and reducing the rotation speed of the fan 20. Here, when the electrical resistance ratio of the humidity control device 30 falls below the predetermined range, this refers to, for example, when the predetermined range of the electrical resistance ratio is 1.1 to 2.5, the electrical resistance ratio falls to a predetermined value less than 1.1 (e.g., 1.0, 0.9, etc.). When the electrical resistance ratio of the humidity control device 30 falls below the predetermined range, it can be said that the temperature rise capability of the humidity control device 30 is insufficient. Therefore, the control unit 40 performs at least one of the actions described above to enhance the temperature rise capability of the humidity control device 30. Specifically, the temperature rise capability of the humidity control device 30 itself is enhanced by extending the time for which electricity is applied to the humidity control device 30 or increasing the voltage applied to the humidity control device 30. Furthermore, by reducing the rotation speed of the ventilator 20, the flow rate of air flowing into the humidity control device 30 is reduced, suppressing heat exchange between the humidity control device 30 and the air, and increasing the temperature rise of the humidity control device 30. This makes it possible to efficiently operate the regeneration mode of the humidity control device 30 while suppressing battery consumption.

[0037] When the electrical resistance ratio of the humidity control device 30 exceeds a predetermined range, the control unit 40 executes at least one selected from shortening the time for which electricity is applied to the humidity control device 30, reducing the voltage applied to the humidity control device 30, and increasing the rotation speed of the fan 20. Here, when the electrical resistance ratio of the humidity control device 30 exceeds the predetermined range, for example, when the predetermined range of the electrical resistance ratio is 1.1 to 2.5, this refers to the electrical resistance ratio reaching a predetermined value greater than 2.5 (e.g., 2.6, 2.7, etc.). When the electrical resistance ratio of the humidity control device 30 exceeds the predetermined range, it can be said that the temperature of the humidity control device 30 is excessively increased. Therefore, the control unit 40 executes at least one of the above to reduce the temperature increase rate of the humidity control device 30. Specifically, the excessive temperature increase of the humidity control device 30 is suppressed by shortening the time for which electricity is applied to the humidity control device 30 or by reducing the voltage applied to the humidity control device 30. Furthermore, by increasing the rotation speed of the ventilator 20, the flow rate of air flowing into the humidity control device 30 is increased, promoting heat exchange between the humidity control device 30 and the air, and suppressing excessive temperature rise of the humidity control device 30. This makes it possible to efficiently operate the regeneration mode of the humidity control device 30 while suppressing battery consumption.

[0038] When the electrical resistance ratio of the humidity control device 30 deviates from a predetermined range, the control unit 40 may stop the supply of electricity to the humidity control device 30. By performing control in this manner, it is possible to prevent the vehicle air conditioning system from shutting down.

[0039] The control unit 40 may notify the vehicle interior of an abnormality when the electrical resistance ratio of the humidity control device 30 deviates from a predetermined range. By notifying the vehicle interior in this manner, it is possible to notify the driver or a mechanic that it is time to replace the humidity control device 30.

[0040] Other details of each component of the vehicle air conditioning system will be described below.

[0041] (1. Air conditioning duct 10) The air conditioning duct 10 is a flow path through which air can flow. The air conditioning duct 10 includes the flow paths 11 and 12 as described above. The material of the air conditioning duct 10 is not particularly limited, but is preferably a metal from the viewpoint of manufacturability. Examples of materials for the air conditioning duct 10 include stainless steel, titanium alloy, copper alloy, aluminum alloy, brass, etc. Among these, stainless steel is preferred because of its high durability, reliability, and low cost.

[0042] (2. Ventilator 20) The ventilator 20 is a device for circulating air from the vehicle interior or the outside of the vehicle. The ventilator 20 is not particularly limited, and a commercially available ventilator can be used. Furthermore, the fan 20 is electrically connected to the control unit 40, and can control the amount of air by adjusting the rotation speed in accordance with instructions from the control unit 40.

[0043] (3. Humidity Control Device 30) (3-1. Honeycomb structure 31) The shape of the honeycomb structure 31 is not particularly limited. For example, the outer shape of a cross section perpendicular to the flow path direction (the direction in which the cells 34 extend) of the honeycomb structure 31 can be a polygon such as a quadrangle (rectangle, square), pentagon, hexagon, heptagon, or octagon, a circle, or an oval shape (egg, ellipse, oval, rounded rectangle, etc.). The end faces (first end face 33a and second end face 33b) have the same shape as the cross section. When the cross section and end faces are polygonal, the corners may be chamfered.

[0044] The shape of the cells 34 is not particularly limited, but may be a polygon such as a square, pentagon, hexagon, heptagon, or octagon, a circle, or an oval in a cross section perpendicular to the flow path direction of the honeycomb structure 31. These shapes may be used alone or in combination of two or more. Among these shapes, a square or hexagon is preferable. By providing cells 34 of such a shape, pressure loss during air flow can be reduced.

[0045] The honeycomb structure 31 may be a honeycomb bonded body having a plurality of honeycomb segments and a bonding layer bonding the outer peripheral side surfaces of the plurality of honeycomb segments together. By using the honeycomb bonded body, it is possible to increase the total cross-sectional area of ​​the cells 34, which is important for ensuring the air flow rate, while suppressing the occurrence of cracks. The bonding layer can be formed using a bonding material. The bonding material is not particularly limited, but a ceramic material with a solvent such as water added to form a paste can be used. The bonding material may contain a material having PTC properties, or may contain the same material as the outer peripheral wall 32 and the partition walls 35. In addition to the role of bonding the honeycomb segments together, the bonding material can also be used as an outer peripheral coating material after bonding the honeycomb segments.

[0046] From the viewpoints of ensuring the strength of the honeycomb structure 31, reducing pressure loss when air passes through the cells 34, ensuring the amount of functional material carried, and ensuring the contact area with the air flowing within the cells 34, it is desirable to suitably combine the thickness of the partition walls 35, the cell density, and the cell pitch (or the opening ratio of the cells 34). In this specification, cell density is a value obtained by dividing the number of cells by the area of ​​one end face (first end face 33a or second end face 33b) of the honeycomb structure 31 (the total area of ​​the partition walls 35 and cells 34 excluding the outer wall 32). In this specification, the cell pitch refers to a value determined by the following calculation: First, the area per cell is calculated by dividing the area of ​​one end face (first end face 33a or second end face 33b) of the honeycomb structure 31 (the total area of ​​the partition walls 35 and cells 34 excluding the outer peripheral wall 32) by the number of cells. Next, the square root of the area per cell is calculated, and this is defined as the cell pitch. In this specification, the opening ratio of the cells 34 is a value obtained by dividing the total area of ​​the cells 34 partitioned by the partition walls 35 in a cross section perpendicular to the flow direction of the honeycomb structure 31 by the area of ​​one end face (the first end face 33a or the second end face 33b) (the total area of ​​the partition walls 35 and the cells 34 excluding the outer peripheral wall 32). Note that when calculating the opening ratio of the cells 34, the pair of electrodes 37a, 37b and the moisture absorption layer 36 are not taken into consideration.

[0047] In an advantageous embodiment from the viewpoint of carrying a sufficient amount of functional material, the thickness of the partition wall 35 is 0.300 mm or less, and the cell density is 100 cells / cm. 2 In a preferred embodiment, the thickness of the partition walls 35 is 0.200 mm or less, and the cell density is 70 cells / cm. 2 In a more preferred embodiment, the thickness of the partition walls 35 is 0.130 mm or less, and the cell density is 65 cells / cm. 2 or less, and the cell pitch is 1.3 mm or more.

[0048] From the viewpoint of ensuring the strength of the honeycomb structure 31 and keeping the electrical resistance low, the lower limit of the thickness of the partition walls 35 is preferably 0.010 mm or more, more preferably 0.020 mm or more, and even more preferably 0.030 mm or more. From the viewpoint of ensuring the strength of the honeycomb structure 31, keeping the electrical resistance low, and increasing the surface area to promote reaction, adsorption, and desorption, the lower limit of the cell density is 30 cells / cm. 2 Preferably, 35 cells / cm or more. 2 More preferably, 40 cells / cm or more. 2 More preferably, it is equal to or greater than this. From the viewpoint of ensuring the strength of the honeycomb structure 31, maintaining low electrical resistance, and increasing the surface area to promote reaction, adsorption, and desorption, the upper limit of the cell pitch is preferably 2.0 mm or less, more preferably 1.8 mm or less, and even more preferably 1.6 mm or less.

[0049] In an advantageous embodiment from the viewpoint of achieving both a reduction in pressure loss and a maintenance of strength, the thickness of the partition wall 35 is 0.08 to 0.36 mm, and the cell density is 2.54 to 140 cells / cm. 2 In a preferred embodiment, the thickness of the partition walls 35 is 0.09 to 0.35 mm, and the cell density is 15 to 100 cells / cm. 2In a more preferred embodiment, the thickness of the partition walls 35 is 0.14 to 0.30 mm, and the cell density is 20 to 90 cells / cm. 2 The aperture ratio of the cell 34 is 0.85 or more.

[0050] From the viewpoint of ensuring the strength of the honeycomb structure 31, the upper limit of the opening ratio of the cells 34 is preferably 0.94 or less, more preferably 0.92 or less, and even more preferably 0.90 or less.

[0051] The thickness of the peripheral wall 32 is not particularly limited, but is preferably determined based on the following points: First, from the viewpoint of reinforcing the honeycomb structure 31, the thickness of the peripheral wall 32 is preferably 0.05 mm or more, more preferably 0.06 mm or more, and even more preferably 0.08 mm or more. On the other hand, from the viewpoint of increasing the electrical resistance to suppress the initial current and reducing the pressure loss during air circulation, the thickness of the peripheral wall 32 is preferably 1.0 mm or less, more preferably 0.5 mm or less, even more preferably 0.4 mm or less, and even more preferably 0.3 mm or less. In this specification, the thickness of the outer wall 32 refers to the length in the normal direction of the side surface from the boundary between the outer wall 32 and the outermost cell 34 or partition wall 35 to the side surface of the honeycomb structure 31 in a cross section perpendicular to the flow path direction.

[0052] The length of the honeycomb structure 31 in the flow path direction and the cross-sectional area perpendicular to the flow path direction are not particularly limited and may be adjusted according to the required size of the humidity control device 30. For example, when used in a compact humidity control device 30 while ensuring a predetermined function, the honeycomb structure 31 has a length in the flow path direction of 2 to 20 mm and a cross-sectional area perpendicular to the flow path direction of 10 cm. 2 The upper limit of the cross-sectional area perpendicular to the flow path direction is not particularly limited, but may be, for example, 300 cm 2 The following is the result.

[0053] The partition walls 35 constituting the honeycomb structure 31 are made of a material that can generate heat when electricity is applied, and specifically, preferably made of a material having PTC characteristics. If necessary, the peripheral wall 32 may also be made of a material having PTC characteristics, like the partition walls 35. This configuration allows the moisture absorption layer 36 to be directly heated by heat transfer from the heat-generating partition walls 35 (and the peripheral wall 32, if necessary). Furthermore, materials having PTC characteristics have the property that, when their temperature rises and exceeds the Curie point, their resistance value rises sharply, making it difficult for electricity to flow through them. Therefore, when the partition walls 35 (and the peripheral wall 32, if necessary) reach a high temperature, the current flowing through them is limited, thereby suppressing excessive heat generation in the honeycomb structure 31. This also makes it possible to suppress thermal deterioration of the moisture absorption layer 36 due to excessive heat generation.

[0054] From the viewpoint of obtaining appropriate heat generation, the lower limit of the volume resistivity at 25°C of a material having PTC characteristics is preferably 0.5 Ω·cm or more, more preferably 1 Ω·cm or more, and even more preferably 5 Ω·cm or more. From the viewpoint of generating heat at a low driving voltage, the upper limit of the volume resistivity at 25°C of a material having PTC characteristics is preferably 30 Ω·cm or less, more preferably 18 Ω·cm or less, and even more preferably 16 Ω·cm or less. In this specification, the volume resistivity at 25°C of a material having PTC characteristics is measured in accordance with JIS K6271:2008.

[0055] From the viewpoint of being able to generate heat when electrically applied and having PTC characteristics, the outer peripheral wall 32 and the partition walls 35 are preferably made of a material whose main component is barium titanate (BaTiO3). Furthermore, this material is more preferably a ceramic made of a material whose main component is barium titanate (BaTiO3)-based crystal particles in which part of the Ba is substituted with a rare earth element. In this specification, the term "main component" refers to a component that accounts for more than 50 mass% of the total components. The content of BaTiO3-based crystal particles can be determined by fluorescent X-ray analysis. Other crystal particles can also be measured using a similar method.

[0056] The composition formula of BaTiO3-based crystal particles in which part of Ba is replaced by rare earth elements is (Ba 1-x A x )TiO3, where A represents one or more rare earth elements and x is 0.0001≦x≦0.010. A is not particularly limited as long as it is a rare earth element, but is preferably one or more selected from the group consisting of La, Ce, Pr, Nd, Eu, Gd, Dy, Ho, Er, Y, and Yb, and more preferably La. x is preferably 0.001 or more, more preferably 0.0015 or more, from the viewpoint of preventing the electrical resistance at room temperature from becoming too high. On the other hand, x is preferably 0.009 or less, from the viewpoint of preventing the electrical resistance at room temperature from becoming too high due to insufficient sintering. The content of BaTiO3-based crystal particles in the ceramic, in which Ba is partially substituted with a rare earth element, is not particularly limited as long as it is an amount that serves as the main component, but is preferably 90 mass% or more, more preferably 92 mass% or more, and even more preferably 94 mass% or more. The upper limit of the content of BaTiO3-based crystal particles is not particularly limited, but is generally 99 mass%, preferably 98 mass%.

[0057] From the viewpoint of reducing environmental impact, it is desirable that the materials used for the outer peripheral wall 32 and the partition wall 35 be substantially free of lead (Pb). Specifically, the Pb content of the outer peripheral wall 32 and the partition wall 35 is preferably 0.01% by mass or less, more preferably 0.001% by mass or less, and even more preferably 0% by mass. A low Pb content allows, for example, air heated by contact with the partition wall 35 during heat generation to be safely applied to living organisms such as humans. The Pb content of the outer peripheral wall 32 and the partition wall 35, calculated as PbO, is preferably less than 0.03% by mass, more preferably less than 0.01% by mass, and even more preferably 0% by mass. The lead content can be determined by ICP-MS (inductively coupled plasma mass spectrometry).

[0058] The Curie points of the materials constituting the outer peripheral wall 32 and the partition walls 35 are preferably in the temperature range at which the resistance value becomes at least twice the resistance value at room temperature (25°C). If the Curie points are in this temperature range, the current flowing through them is limited when the humidity control device 30 becomes hot, so that excessive heat generation in the humidity control device 30 is efficiently suppressed. Therefore, thermal degradation of the moisture absorbing layer 36 caused by excessive heat generation can be suppressed. The lower limit of the Curie point of the material constituting the outer peripheral wall 32 and the partition wall 35 is preferably 80°C or higher, more preferably 100°C or higher, even more preferably 110°C or higher, and particularly preferably 125°C or higher, from the viewpoint of efficiently heating the moisture absorbing layer 36. The upper limit of the Curie point is preferably 200°C or lower, more preferably 190°C or lower, even more preferably 180°C or lower, and particularly preferably 150°C or lower, from the viewpoint of safety as a part placed in or near the vehicle interior.

[0059] The Curie point of the material forming the outer peripheral wall 32 and the partition walls 35 can be adjusted by the type and amount of the shifter added. For example, the Curie point of barium titanate (BaTiO) is approximately 120°C, but by substituting part of the Ba and Ti with one or more of Sr, Sn, and Zr, the Curie point can be shifted to a lower temperature.

[0060] In this specification, the Curie point is measured by the following method: A sample is attached to a sample holder for measurement and placed in a measurement chamber (e.g., MINI-SUBZERO MC-810P, manufactured by Espec Corporation). The change in the sample's electrical resistance relative to temperature is measured as the temperature rises from 10°C using a DC resistance meter (e.g., Multimeter 3478A, manufactured by Hewlett-Packard Japan, LLC). The Curie point is determined by the temperature at which the resistance value, based on the electrical resistance-temperature plot obtained from the measurement, is twice the resistance value at room temperature (25°C).

[0061] (3-2. Pair of electrodes 37a, 37b) The positions of the pair of electrodes 37a, 37b are not particularly limited, but may be provided on the first end face 33a and the second end face 33b as shown in Fig. 2A. The pair of electrodes 37a, 37b may also be provided on the outer peripheral wall 32 parallel to the extension direction of the cells 34. By applying a voltage between the pair of electrodes 37a and 37b, it becomes possible to cause the honeycomb structure 31 to generate heat by Joule heat.

[0062] The pair of electrodes 37a, 37b is not particularly limited, and may be, for example, a metal or alloy containing at least one selected from Cu, Ag, Al, Ni, and Si. Alternatively, an ohmic electrode capable of making ohmic contact with the outer peripheral wall 32 and / or the partition wall 35 having PTC characteristics may be used. The ohmic electrode may contain, for example, at least one selected from Al, Au, Ag, and In as a base metal and at least one selected from Ni, Si, Zn, Ge, Sn, Se, and Te as a dopant for n-type semiconductors. The pair of electrodes 37a, 37b may have a single-layer structure or a stacked structure of two or more layers. When the pair of electrodes 37a, 37b has a stacked structure of two or more layers, the materials of the layers may be the same or different.

[0063] The thickness of the pair of electrodes 37a, 37b can be set appropriately depending on the method for forming the pair of electrodes 37a, 37b. Examples of methods for forming the pair of electrodes 37a, 37b include metal deposition methods such as sputtering, vapor deposition, electrolytic deposition, and chemical deposition. The pair of electrodes 37a, 37b can also be formed by applying an electrode paste and then baking it, or by thermal spraying. Furthermore, the pair of electrodes 37a, 37b may be formed by joining metal or alloy plates.

[0064] The thickness of the pair of electrodes 37a, 37b is preferably about 5 to 30 μm for baking of electrode paste, about 100 to 1000 nm for dry plating such as sputtering and vapor deposition, about 10 to 100 μm for thermal spraying, and about 5 to 30 μm for wet plating such as electrolytic deposition and chemical deposition. Furthermore, when joining metal or alloy plates, the thickness is preferably about 5 to 100 μm.

[0065] (3-3. Terminal 38) Terminal 38 is connected to the pair of electrodes 37a, 37b and is provided on at least a portion of the pair of electrodes 37a, 37b. Providing terminal 38 facilitates connection to an external power source. Terminal 38 is connected to a conductor that is connected to the external power source.

[0066] The material of the terminal 38 is not particularly limited, but may be, for example, a metal. As the metal, a single metal or an alloy may be used, but from the viewpoints of corrosion resistance, electrical resistivity, and linear expansion coefficient, an alloy containing at least one selected from the group consisting of Cr, Fe, Co, Ni, Cu, Al, and Ti is preferable, and stainless steel, an Fe-Ni alloy, and phosphor bronze are more preferable.

[0067] The size and shape of the terminal 38 are not particularly limited. For example, as shown in Fig. 2A, the terminal 38 may be provided over the entire pair of electrodes 37a, 37b on the outer peripheral wall 32. The terminal 38 may also be provided over a portion of the pair of electrodes 37a, 37b on the outer peripheral wall 32, or may be provided so as to extend outward beyond the outer edges of the pair of electrodes 37a, 37b on the outer peripheral wall 32. The terminal 38 may also be provided over a portion of the pair of electrodes 37a, 37b on the partition wall 35, or may be provided so as to cover some of the cells 34. The thickness of the terminal 38 is not particularly limited, but is, for example, 0.01 to 10 mm, typically 0.05 to 5 mm.

[0068] The method of connecting the terminal 38 and the pair of electrodes 37a, 37b is not particularly limited as long as they are electrically connected, and they can be connected by, for example, diffusion bonding, a mechanical pressure mechanism, welding, or the like.

[0069] (3-4. Moisture absorption layer 36) The moisture absorbing layer 36 is a layer containing a moisture absorbing material, and has the function of absorbing moisture (water vapor). The moisture absorbing layer 36 can be provided on the surface of the partition wall 35 (in the case of the outermost cell 34, the partition wall 35 and the outer wall 32 that define the outermost cell 34). By providing the moisture absorbing layer 36 in this manner, moisture can be easily adsorbed during moisture absorption treatment, and the moisture absorbing layer 36 can be easily heated during regeneration treatment, so that the desired function of the moisture absorbing layer 36 can be regenerated.

[0070] The moisture absorbing material contained in the moisture absorbing layer 36 preferably has the function of absorbing moisture at temperatures between -20 and 40°C and releasing moisture at temperatures as high as 60°C or higher. The moisture absorbent is not particularly limited, but examples thereof include aluminosilicate, silica gel, silica, graphene oxide, polymer adsorbent, polystyrene sulfonic acid, and metal organic framework (MOF). These may be used alone or in combination of two or more.

[0071] The aluminosilicate is preferably a porous clay mineral such as AFI-type, CHA-type or BEA-type zeolite, allophane, imogolite, etc. The aluminosilicate is preferably amorphous.

[0072] As the silica gel, it is preferable to use type A silica gel. The polymer adsorbent is preferably one having a polyacrylic acid polymer chain, such as sodium polyacrylate. The metal-organic framework is a crystalline hybrid material containing metal ions and organic molecules (organic ligands). The metal ions are preferably hydrophilic metal ions (e.g., aluminum ions).

[0073] The moisture absorption layer 36 is preferably capable of adsorbing carbon dioxide and / or volatile components in addition to moisture. Specifically, the moisture absorption layer 36 can further contain an adsorbent capable of adsorbing carbon dioxide and / or volatile components in addition to a moisture absorbent capable of adsorbing moisture. Furthermore, if the moisture absorbent capable of adsorbing moisture can also adsorb carbon dioxide and / or volatile components, by containing only the moisture absorbent, it is possible to adsorb carbon dioxide and / or volatile components in addition to moisture. By containing such an adsorbent or using such a moisture absorbent, it is possible to obtain an air purification effect in addition to an air dehumidification effect. The adsorbent preferably has a function of being able to adsorb carbon dioxide and / or volatile components at temperatures between -20 and 40°C and desorb them at high temperatures of 60°C or higher. Examples of adsorbents having such functions include zeolite, silica gel, activated carbon, alumina, silica, low-crystalline clay, and amorphous aluminum silicate complexes. The type of adsorbent may be appropriately selected depending on the type of component to be removed. One type of adsorbent may be used alone, or two or more types may be used in combination.

[0074] Volatile components contained in the air inside a vehicle cabin include, for example, volatile organic compounds (VOCs) and odor components other than VOCs. Specific examples of volatile components include ammonia, acetic acid, isovaleric acid, nonenal, formaldehyde, toluene, xylene, paradichlorobenzene, ethylbenzene, styrene, chlorpyrifos, di-n-butyl phthalate, tetradecane, di-2-ethylhexyl phthalate, diazinon, acetaldehyde, and N-methylcarbamate-2-(1-methylpropyl)phenyl.

[0075] The moisture absorption layer 36 may contain a catalyst. By containing a catalyst, oxidation-reduction reactions and the like can be promoted, thereby purifying carbon dioxide and / or volatile components. Examples of catalysts having such functions include metal catalysts such as Pt, Pd, and Ag, and oxide catalysts such as CeO2 and ZrO2. One type of catalyst may be used alone, or two or more types may be used in combination. Furthermore, the catalyst may be used in combination with the above-mentioned functional materials.

[0076] The thickness of the moisture absorbing layer 36 is not particularly limited and may be determined depending on the size of the cells 34. For example, from the viewpoint of ensuring sufficient contact with air, the thickness of the moisture absorbing layer 36 is preferably 20 μm or more, more preferably 25 μm or more, and even more preferably 30 μm or more. On the other hand, from the viewpoint of preventing the moisture absorbing layer 36 from peeling off from the partition walls 35 and the outer peripheral wall 32, the thickness of the moisture absorbing layer 36 is preferably 400 μm or less, more preferably 380 μm or less, and even more preferably 350 μm or less.

[0077] The thickness of the moisture absorption layer 36 is measured by the following procedure. An arbitrary cross section parallel to the flow path direction of the honeycomb structure 31 is cut out, and a cross-sectional image at approximately 50x magnification is obtained using a scanning electron microscope or the like. This cross section is also taken so as to pass through the center of gravity of the cross section perpendicular to the flow path of the honeycomb structure 31. For each moisture absorption layer 36 visible in the cross-sectional image, the thickness is calculated by dividing the cross-sectional area by the length of the cell 34 in the flow path direction. This calculation is performed for all moisture absorption layers 36 visible in the cross-sectional image, and the overall average value is taken as the thickness of the moisture absorption layer 36.

[0078] From the viewpoint of exhibiting the desired function in the humidity control device 30, the amount of the moisture absorption layer 36 is preferably 50 to 500 g / L, more preferably 100 to 400 g / L, and even more preferably 150 to 350 g / L relative to the volume of the honeycomb structure 31. The volume of the honeycomb structure 31 is a value determined by the outer dimensions of the honeycomb structure 31.

[0079] (3-5. Manufacturing Method of Humidity Control Device 30) The method for producing the humidity control device 30 is not particularly limited and can be carried out in accordance with a known method. The method for producing the humidity control device 30 will be exemplified below. The method for manufacturing the honeycomb structure 31 that constitutes the humidity control device 30 includes a molding step and a firing step. In the molding step, a clay containing ceramic raw materials including BaCO3 powder, TiO2 powder, and powder of a rare earth nitrate or hydroxide is molded to produce a honeycomb molded body with a relative density of 60% or more. The ceramic raw material can be obtained by dry mixing each powder to obtain a desired composition. The clay can be obtained by adding a dispersion medium, a binder, a plasticizer, and a dispersant to a ceramic raw material and kneading the mixture. The clay may contain additives such as a sifter, a metal oxide, a property improver, and a conductive powder, as needed. The blending amount of components other than the ceramic raw materials is not particularly limited as long as it is an amount that allows the relative density of the honeycomb formed body to be 60% or more.

[0080] Here, in this specification, the "relative density of the honeycomb formed body" means the ratio of the density of the honeycomb formed body to the true density of the entire ceramic raw material. Specifically, it can be calculated by the following formula. Relative density (%) of honeycomb formed body = Density of honeycomb formed body (g / cm 3 ) / true density of the entire ceramic raw material (g / cm 3 ) x 100 The density of the honeycomb formed body can be measured by the Archimedes method using pure water as a medium. The true density of the entire ceramic raw material is calculated by multiplying the total mass (g) of each raw material by the total actual volume (cm) of each raw material. 3 ) can be calculated by dividing by

[0081] Examples of the dispersion medium include water and a mixed solvent of water and an organic solvent such as alcohol, with water being particularly preferred.

[0082] Examples of binders include organic binders such as methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and polyvinyl alcohol. It is particularly preferable to use a combination of methyl cellulose and hydroxypropoxyl cellulose. While one binder may be used alone or two or more binders may be used in combination, it is preferable that the binder does not contain an alkali metal element.

[0083] Examples of the plasticizer include polyoxyalkylene alkyl ether, polycarboxylic acid polymer, and alkyl phosphate ester.

[0084] The dispersant may be a surfactant such as polyoxyalkylene alkyl ether, ethylene glycol, dextrin, fatty acid soap, polyalcohol, etc. The dispersant may be used alone or in combination of two or more.

[0085] The honeycomb formed body can be produced by extrusion molding of a clay. In extrusion molding, a die having a desired overall shape, cell shape, partition wall thickness, cell density, etc. can be used.

[0086] The relative density of the honeycomb formed body obtained by extrusion molding is 60% or more, preferably 65% ​​or more. By controlling the relative density of the honeycomb formed body within this range, it is possible to densify the honeycomb formed body and reduce its electrical resistance at room temperature. The upper limit of the relative density of the honeycomb formed body is not particularly limited, but is generally 80%, preferably 75%.

[0087] The honeycomb molded body can be dried before the firing step. The drying method is not particularly limited, and for example, a conventionally known drying method such as hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying, etc. Among these, a drying method that combines hot air drying with microwave drying or dielectric drying is preferred because it can dry the entire molded body quickly and uniformly.

[0088] The firing step involves holding the temperature at 1150 to 1250°C, then raising the temperature to a maximum temperature of 1360 to 1430°C at a rate of 20 to 600°C / hour, and holding the temperature for 0.5 to 10 hours. By holding the honeycomb formed body at a maximum temperature of 1360 to 1430°C for 0.5 to 10 hours, a honeycomb structure 31 containing, as a main component, BaTiO3-based crystal particles in which part of Ba has been substituted with a rare earth element can be obtained. Furthermore, by maintaining the temperature at 1150 to 1250°C, Ba2TiO4 crystal particles generated during the firing process can be easily removed, and the honeycomb structure 31 can be made dense. Furthermore, by setting the heating rate from 1150 to 1250°C to the maximum temperature of 1360 to 1430°C at 20 to 600°C / hour, 1.0 to 10.0 mass% of Ba6Ti 17 O 40 Crystal grains can be generated in the honeycomb structure 31 .

[0089] The holding time at 1150 to 1250°C is not particularly limited, but is preferably 0.5 to 10 hours. By holding for such a time, Ba2TiO4 crystal particles formed during the firing process can be stably and easily removed.

[0090] The firing step preferably includes holding the mixture at 900 to 950°C for 0.5 to 5 hours during heating. Holding the mixture at 900 to 950°C for 0.5 to 5 hours allows BaCO3 to efficiently decompose, making it easier to obtain a honeycomb structure 31 having a predetermined composition.

[0091] Before the firing step, a degreasing step may be carried out to remove the binder. The degreasing step is preferably carried out in an air atmosphere to completely decompose the organic components. Furthermore, the firing step is preferably carried out in an air atmosphere from the viewpoint of controlling electrical properties and reducing manufacturing costs. The firing furnace used in the firing step and degreasing step is not particularly limited, but an electric furnace, a gas furnace, or the like can be used.

[0092] A pair of electrodes 37a, 37b are formed on the honeycomb structure 31 obtained in this manner. The pair of electrodes 37a, 37b can be formed by a metal deposition method such as sputtering, vapor deposition, electrolytic deposition, or chemical deposition. The pair of electrodes 37a, 37b can also be formed by applying an electrode paste and then baking it. Furthermore, the pair of electrodes 37a, 37b can also be formed by thermal spraying. The pair of electrodes 37a, 37b may be formed of a single layer, or may be formed of multiple electrode layers with different compositions. Representative methods for forming the pair of electrodes 37a, 37b will be described below.

[0093] First, an electrode slurry containing an electrode material, an organic binder, and a dispersion medium is prepared and applied to the first end face 33a or the second end face 33b of the honeycomb structure 31. The dispersion medium can be water, an organic solvent (e.g., toluene, xylene, ethanol, n-butanol, ethyl acetate, butyl acetate, terpineol, dihydroterpineol, texanol, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether), or a mixture thereof. Excess slurry on the outer periphery of the honeycomb structure 31 is removed by blowing and wiping. Thereafter, the slurry is dried to form a pair of electrodes 37a, 37b on the first end face 33a or the second end face 33b of the honeycomb structure 31. Drying can be performed while heating the honeycomb structure 31 to a temperature of, for example, about 120 to 600°C. The series of steps of coating, slurry removal, and drying may be carried out only once, but by repeating these steps multiple times, a pair of electrodes 37a, 37b of a desired thickness can be provided.

[0094] Next, terminals 38 are placed at predetermined positions of the pair of electrodes 37a, 37b, and the pair of electrodes 37a, 37b are connected to the terminals 38. The method for connecting the pair of electrodes 37a, 37b to the terminals 38 can be the method described above. The terminal 38 may be installed after the moisture absorbing layer 36 described below is formed.

[0095] Next, a moisture absorbing layer 36 is formed on the surfaces of the partition walls 35 and the like of the honeycomb structure 31 . The method for forming the moisture absorption layer 36 is not particularly limited, and it can be formed, for example, by the following process. The honeycomb structure 31 is immersed in a slurry containing a moisture absorbent, an organic binder, and a dispersion medium for a predetermined period of time, and excess slurry on the end faces and outer periphery of the honeycomb structure 31 is removed by blowing and wiping. The dispersion medium can be water, an organic solvent (e.g., toluene, xylene, ethanol, n-butanol, ethyl acetate, butyl acetate, terpineol, dihydroterpineol, Texanol, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether), or a mixture thereof. Thereafter, the slurry is dried to form the moisture absorption layer 36 on the surface of the partition wall 35. The drying can be performed while heating the honeycomb structure 31 to a temperature of, for example, about 120 to 600°C. The series of steps of immersion, slurry removal, and drying may be carried out only once, but by repeating the steps multiple times, a moisture absorbing layer 36 of a desired thickness can be provided on the surface of the partition wall 35 or the like.

[0096] (4. Control unit 40) The control unit 40 is electrically connected to the ventilator 20, the humidity control device 30, and the valve 51. A power source (not shown) may be disposed between each component and the control unit 40. The power source is not particularly limited, and a battery or the like can be used. The control unit 40 controls the power supply to control the state of voltage application to the pair of electrodes 37a, 37b of the humidity control device 30, and can adjust the heating state of the honeycomb structure 31. The control unit 40 also controls the valve 51 to control the flow of air. Furthermore, the control unit 40 can control the flow rate of air circulating in the air conditioning duct 10 by adjusting the rotation speed of the fan 20.

[0097] The control unit 40 is not particularly limited, but is generally an ECU (Engine (electronic) Control Unit). The ECU includes a CPU that executes various arithmetic processes, a ROM that stores programs and data required for the control, a RAM that temporarily stores the results of the CPU calculations, and an input / output port for inputting and outputting signals to and from the outside.

[0098] The control unit 40 can execute a dehumidification (moisture absorption) mode and a regeneration mode. These modes will be described below. (Dehumidification mode) In the dehumidification mode, the control unit 40 controls the valve 51 so that air flows into the flow path 11. Specifically, the control unit 40 switches the valve 51 so that air flows into the flow path 11 but does not flow into the flow path 12. By controlling in this manner, the air in the air conditioning duct 10 is dehumidified in the humidity control device 30 and can be returned to the vehicle cabin via the flow path 11.

[0099] (Playback mode) In the regeneration mode, the control unit 40 controls the valve 51 so that air flows into the flow path 12. Specifically, the control unit 40 switches the valve 51 so that air does not flow into the flow path 11 and air flows into the flow path 12. The control unit 40 also applies a voltage to the humidity control device 30 to heat it. By performing this control, the moisture trapped in the moisture absorption layer 36 is released, and the moisture-containing air is discharged outside the vehicle through the flow path 12.

[0100] In the regeneration mode, it is preferable to heat the moisture absorption layer 36 to a temperature equal to or higher than the desorption temperature depending on the type of moisture absorbent material in order to promote desorption of moisture trapped in the moisture absorption layer 36. For example, it is preferable to heat the moisture absorption layer 36 to 70 to 150°C, more preferably to 80 to 140°C, and even more preferably to 90 to 130°C.

[0101] From the viewpoint of stably performing the above control, it is desirable that the humidity control device 30 be placed in a position close to the vehicle interior. Therefore, from the viewpoint of preventing electric shock, etc., it is preferable that the driving voltage of the humidity control device 30 is 60 V or less. The honeycomb structure 31 used in the humidity control device 30 has low electrical resistance at room temperature, so that the honeycomb structure 31 can be heated at this low driving voltage. The lower limit of the driving voltage is not particularly limited, but is preferably 10 V or more. If the driving voltage is less than 10 V, the current when heating the honeycomb structure 31 will be large, and therefore the conductor wires will need to be thicker. On the other hand, if measures to prevent electric shock (insulation) are possible, a higher driving voltage for the humidity control device 30 is advantageous because it allows the regeneration mode to be completed in a shorter time. However, if the driving voltage for the humidity control device 30 is too high, the insulation measures become more complicated and power consumption increases. Therefore, when measures to prevent electric shock are possible, the driving voltage for the humidity control device 30 is preferably 60 to 1000 V, and more preferably 300 to 800 V.

[0102] The electric vehicle according to the first embodiment of the present invention is equipped with a vehicle air conditioning system having the above-described features. Therefore, this electric vehicle can conserve battery power in the vehicle air conditioning system and improve cruising range without impeding comfortable driving. Furthermore, this electric vehicle can prevent system downtime in the vehicle air conditioning system and can also know when to replace the humidity control device 30.

[0103] <Embodiment 2> FIG. 3 is a schematic diagram showing the overall configuration of a vehicle air conditioning system according to a second embodiment of the present invention. 3, the vehicle air conditioning system according to the second embodiment of the present invention is different from the vehicle air conditioning system according to the first embodiment of the present invention in that a first flow path 13 in which a humidity control device 30 is disposed and a second flow path 14 in which the humidity control device 30 is not disposed are branched downstream of the ventilator 20, and a first valve 52 is further provided in the first flow path 13 upstream of the humidity control device 30, and a second valve 53 is further provided in the second flow path 14. The first valve 52 and the second valve 53 are controlled by the control unit 40. Other configurations of the vehicle air conditioning system according to the second embodiment of the present invention are basically the same as those of the vehicle air conditioning system according to the first embodiment of the present invention, so a description of the same configurations will be omitted. Note that components having the same reference numerals as those appearing in the description of the vehicle air conditioning system according to embodiment 1 of the present invention are the same as those in the vehicle air conditioning system according to embodiment 2 of the present invention.

[0104] The first flow path 13 branches into a flow path 11 that introduces air into the vehicle cabin and a flow path 12 that discharges air to the outside of the vehicle. The flow path 11 merges with the second flow path 14 downstream to form a third flow path 15 that returns air to the vehicle cabin. The third flow path 15 may be provided with known components (not shown) used for heating and cooling, such as an evaporator or a condenser, as necessary.

[0105] The first valve 52 is a valve that can adjust the amount of air that flows into the humidity control device 30. The second valve 53 is a valve that can adjust the amount of air that flows into the second flow path 14. The position of the second valve 53 is not particularly limited as long as it is within the second flow path 14, and it may be on the upstream side or downstream side of the second flow path 14. The first valve 52 and the second valve 53 are not particularly limited as long as they have the above-mentioned functions, and known valves such as tamper valves and butterfly valves can be used.

[0106] In the vehicle air conditioning system according to the second embodiment of the present invention, the control unit 40 is electrically connected to the ventilator 20, the humidity control device 30, and each valve (the valve 51, the first valve 52, and the second valve 53). The control unit 40 can execute a dehumidification (moisture absorption) mode, a regeneration mode, and a fan mode. These modes will be described below.

[0107] (Dehumidification mode) In the dehumidification mode, the control unit 40 controls the valve 51, the first valve 52, and the second valve 53 so that air flows sequentially into the first flow path 13, the flow path 11, and the third flow path 15. Specifically, the control unit 40 opens the first valve 52, closes the second valve 53, and switches the valve 51 so that air does not flow into the flow path 12 but flows into the flow path 11. By controlling in this manner, the air that flows into the first flow path 13 is dehumidified in the humidity control device 30 and can be returned to the vehicle cabin via the flow path 11 and the third flow path 15. In this dehumidification mode, the control unit 40 may control the second valve 53 so that a portion of the air flows into the second flow path 14. By controlling in this manner, excessive dehumidification can be suppressed, and the humidity of the air in the vehicle cabin can be optimized.

[0108] (Playback mode) In the regeneration mode, the control unit 40 controls the valve 51, the first valve 52, and the second valve 53 so that air flows sequentially into the first flow path 13 and the flow path 12. Specifically, the control unit 40 opens the first valve 52, closes the second valve 53, and switches the valve 51 so that air does not flow into the flow path 11 and air flows into the flow path 12. The control unit 40 also applies a voltage to the humidity control device 30 to heat it. By performing this control, the moisture captured in the moisture absorption layer 36 is released, and the moisture-containing air is discharged outside the vehicle through the flow path 12. In this regeneration mode, the control unit 40 may control the second valve 53 so that a portion of the air flows into the second flow path 14. By controlling in this manner, air is constantly circulating within the vehicle air conditioning system, so that cooling or heating can be continuously performed by an evaporator or the like provided downstream of the third flow path 15.

[0109] When the humidity control device 30 is in a regeneration mode, the control unit 40 monitors the electrical resistance of the humidity control device 30 (specifically, the honeycomb structure 31) and calculates the electrical resistance ratio of the electrical resistance at the end of current application to the electrical resistance at the start of current application. If the electrical resistance ratio deviates from a predetermined range, the control unit 40 controls at least one selected from the duration of current application to the humidity control device 30, the input voltage, and the rotation speed of the fan 20. By controlling in this manner, an abnormality in the humidity control device 30 can be predicted and battery consumption associated with the abnormality in the humidity control device 30 can be reduced. As a result, battery consumption can be reduced and the cruising range of the electric vehicle can be improved without impeding comfortable driving. Note that the control method by the control unit 40 is the same as that of the vehicle air conditioning system according to the first embodiment of the present invention, and therefore further description thereof will be omitted.

[0110] The control unit 40 may close the first valve 52 when the electrical resistance ratio of the humidity control device 30 deviates from a predetermined range. By performing control in this manner, it is possible to prevent the vehicle air conditioning system from shutting down. In this case, it is preferable to open the second valve 53 to allow air to flow into the vehicle compartment through the second flow path 14. By controlling in this manner, air is constantly circulating within the vehicle air conditioning system, so that cooling or heating can be continuously performed by an evaporator or the like provided downstream of the third flow path 15.

[0111] (Blowing mode) The air blowing mode is performed when dehumidification by the humidity control device 30 or regeneration of the humidity control device 30 is not required. In the air blowing mode, the control unit 40 controls the first valve 52 and the second valve 53 so that air sequentially flows into the second flow path 14 and the third flow path 15. Specifically, the control unit 40 controls the first valve 52 to close and the second valve 53 to open. By performing control in this manner, the air that flows into the second flow path 14 can be returned to the vehicle cabin via the third flow path 15. At this time, cooling or heating may be performed by an evaporator or the like provided downstream of the third flow path 15. Therefore, when dehumidification by the humidity control device 30 or regeneration of the humidity control device 30 is not performed, the load on the fan 20 can be reduced, thereby achieving power saving.

[0112] The electric vehicle according to the second embodiment of the present invention is equipped with a vehicle air conditioning system having the above-described features. Therefore, this electric vehicle can conserve battery power in the vehicle air conditioning system and improve cruising range without impeding comfortable driving. Furthermore, this electric vehicle can prevent system downtime in the vehicle air conditioning system and can also know when to replace the humidity control device 30.

[0113] <Embodiment 3> FIG. 4 is a schematic diagram showing the overall configuration of a vehicle air conditioning system according to a third embodiment of the present invention. 4, the vehicle air conditioning system according to the third embodiment of the present invention differs from the vehicle air conditioning system according to the second embodiment of the present invention in that it further includes a third valve 54 that is capable of adjusting the inflow rate of air from the vehicle compartment and air from outside the vehicle, upstream of the ventilator 20. The third valve 54 is controlled by the control unit 40. Other configurations of the vehicle air conditioning system according to the third embodiment of the present invention are basically the same as those of the vehicle air conditioning systems according to the first and second embodiments of the present invention, and therefore a description of the same configurations will be omitted. In addition, components having the same reference numerals as those appearing in the description of the vehicle air conditioning systems according to embodiments 1 and 2 of the present invention are the same as the components of the vehicle air conditioning system according to embodiment 3 of the present invention.

[0114] In the vehicle air conditioning system according to the third embodiment of the present invention, the air conditioning duct 10 branches upstream of the ventilator 20 into a fourth flow path 16 through which air from the vehicle compartment flows in and a fifth flow path 17 through which air from outside the vehicle flows in, and a third valve 54 is provided at the branch point. The third valve 54 is not particularly limited as long as it can adjust the amount of air flowing through each flow path, and any known valve can be used. Specifically, the valve 51 may be electrically driven and have the function of switching the flow paths, and a solenoid valve, an electric valve, or the like can be used. Furthermore, a tamper valve, a butterfly valve, or the like may be provided in each of the fourth flow path 16 and the fifth flow path 17.

[0115] The vehicle air conditioning system according to the third embodiment of the present invention can execute a dehumidification (moisture absorption) mode, a regeneration mode, and an air blowing mode, similar to the vehicle air conditioning system according to the second embodiment of the present invention.

[0116] When the electrical resistance ratio of the humidity control device 30 deviates from a predetermined range, the control unit 40 may adjust the humidity inside the vehicle compartment by controlling the third valve 54 so as to increase the amount of air flowing in from outside the vehicle. If the electrical resistance ratio of the humidity control device 30 falls outside a predetermined range, the first valve 52 is closed to prevent the vehicle air conditioning system from shutting down, and the second valve 53 is opened to ensure airflow into the vehicle cabin. If a large amount of air flows in from the vehicle cabin at this time, humidity increases, making it more likely for windows to fogging up. Therefore, by controlling the third valve 54 to increase the amount of air flowing in from outside the vehicle (outside air) as described above, it is possible to optimize the internal air circulation rate and suppress window fogging.

[0117] The vehicle air conditioning system according to the third embodiment of the present invention may be provided with a humidity sensor in the vehicle compartment, and the control unit 40 may control the third valve 54 based on the humidity measured by the humidity sensor. By controlling in this manner, it is possible to stably suppress the occurrence of fogging on the windows. The location of the humidity sensor is not particularly limited as long as it is located inside the vehicle, and it may be located near a window or the like.

[0118] In the above description, the third valve 54 is applied to the vehicle air conditioning system according to the second embodiment of the present invention, but the third valve 54 may also be applied to the vehicle air conditioning system according to the first embodiment of the present invention. In this case, the same effects as those described above can be obtained.

[0119] The electric vehicle according to the third embodiment of the present invention is equipped with a vehicle air conditioning system having the above-described features. Therefore, this electric vehicle can conserve battery power in the vehicle air conditioning system and improve cruising range without impeding comfortable driving. Furthermore, this electric vehicle can prevent system downtime of the vehicle air conditioning system in advance and can also know when to replace the humidity control device 30. [Explanation of symbols]

[0120] 10 Air conditioning ducts 11,12 Flow path 13 First Channel 14 Second Flow Path 15 Third Channel 16 Fourth Channel 17 5th Channel 20 Ventilator 30 Humidity Control Device 31 Honeycomb structure 32 Outer wall 33a 1st end surface 33b 2nd end face 34 cells 35 Bulkhead 36 Moisture absorption layer 37a,37b electrode 38 terminals 40 Control Unit 51 Valve 52 First valve 53 Second valve 54 Third valve

Claims

1. an air conditioning duct through which air from the vehicle interior and / or outside the vehicle can flow; a fan disposed in the air conditioning duct; a honeycomb structure having an outer peripheral wall, and partition walls disposed inside the outer peripheral wall and defining a plurality of cells that serve as the air flow path extending from a first end face to a second end face; and a humidity control device having a moisture absorption layer provided on a surface of the partition wall, the humidity control device being disposed in the air conditioning duct downstream of the fan; a control unit that controls the humidity control device and the ventilator; A vehicle air conditioning system comprising: the control unit, when in a regeneration mode for the humidity control device, monitors the electrical resistance of the humidity control device and calculates an electrical resistance ratio of the electrical resistance at the end of current application to the electrical resistance at the start of current application; When the electrical resistance ratio deviates from a predetermined range, the control unit controls at least one selected from the power supply time and input voltage to the humidity control device, and the rotation speed of the fan.

2. 2. The vehicle air conditioning system according to claim 1, wherein the control unit, when the electrical resistance ratio becomes smaller than a predetermined range, performs at least one selected from extending the energization time, increasing the applied voltage, and decreasing the rotation speed.

3. 2. The vehicle air conditioning system according to claim 1, wherein the control unit, when the electrical resistance ratio becomes larger than a predetermined range, performs at least one selected from the group consisting of shortening the energization time, reducing the applied voltage, and increasing the rotation speed.

4. 4. The vehicle air conditioning system according to claim 1, wherein the predetermined range of the electrical resistance ratio is 1.1 to 2.

5.

5. the air conditioning duct is branched downstream of the fan into a first flow path in which the humidity control device is disposed and a second flow path in which the humidity control device is not disposed, a first valve capable of adjusting an inflow amount of the air in the first flow path upstream of the humidity control device, and a second valve capable of adjusting an inflow amount of the air in the second flow path; the first valve and the second valve are controlled by the control unit, The vehicle air conditioning system according to claim 1 , wherein the control unit closes the first valve when the electrical resistance ratio falls outside a predetermined range.

6. The vehicle air conditioning system according to claim 1 , wherein the control unit stops the supply of electricity to the humidity control device when the electrical resistance ratio falls outside a predetermined range.

7. a third valve arranged upstream of the fan and configured to adjust the amount of air flowing in from the vehicle compartment and the amount of air flowing in from outside the vehicle; 7. The vehicle air conditioning system according to claim 5, wherein the control unit adjusts the humidity in the vehicle compartment by controlling the third valve so as to increase the amount of air flowing in from outside the vehicle when the electrical resistance ratio deviates from a predetermined range.

8. A humidity sensor is installed inside the vehicle. The vehicle air conditioning system according to claim 7, wherein the control unit controls the third valve based on the humidity measured by the humidity sensor.

9. 4. The vehicle air conditioning system according to claim 1, wherein the control unit issues a notice of an abnormality to a passenger compartment when the electrical resistance ratio deviates from a predetermined range.

10. 4. The vehicle air conditioning system according to claim 1, wherein at least the partition walls of the honeycomb structure are made of a material having PTC properties.

11. The vehicle air conditioning system according to any one of claims 1 to 3, wherein the humidity control device further comprises a pair of electrodes provided on the first end face and the second end face of the honeycomb structure, or on the outer wall parallel to the direction in which the cells of the honeycomb structure extend.

12. An electric vehicle comprising the vehicle air conditioning system according to any one of claims 1 to 3.

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