Carbon nanotube heater

Abstract

To improve temperature uniformity around the through-hole. [Solution] The pair of electrodes 22 of the CNT heater 1 are arranged side by side in the X direction. The connecting sheet portion 21 is made of a sheet-shaped CNT molded body. The connecting sheet portion 21 extends in the X direction and in the Y direction perpendicular to the X direction, connecting the pair of electrodes 22. The connecting sheet portion 21 generates heat when power is supplied to it. The additional conductive portion 23 is laminated on the connecting sheet portion 21 in an arrangement region that includes the area around the first through hole 211 provided in the connecting sheet portion 21 that intersects with a first virtual straight line extending in the X direction through the center of the first through hole 211. The conductivity of the additional conductive portion 23 in the Y direction is higher than the conductivity of the connecting sheet portion 21 in the Y direction. This makes it possible to improve the uniformity of the temperature of the CNT heater 1 around the first through hole 211.

Description

Technical Field

[0001] The present invention relates to a carbon nanotube heater.

Background Art

[0002] In recent years, it has been proposed to form a large number of carbon nanotubes into various shapes and use them in various products such as heaters and sensors. For example, Patent Document 1 discloses a carbon nanotube heater including a pair of electrodes and a sheet-shaped carbon nanotube molded body connecting between the pair of electrodes. In the carbon nanotube heater, when an electric current flows between the pair of electrodes, the sheet-shaped carbon nanotube molded body generates heat.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the CNT heater as described above, when attaching the CNT heater to an object, a through hole may be provided in the CNT heater so that the structure such as a protrusion of the object does not overlap with the CNT heater. In this case, since the electric current flowing between the pair of electrodes flows deviating from the direction passing through the through hole, the temperature of the CNT heater around the through hole may vary greatly in the circumferential direction.

[0005] The present invention has been made in view of the above problems, and aims to improve the uniformity of the temperature around the through hole.

Means for Solving the Problems

[0006] One aspect of the present invention is a carbon nanotube heater comprising: a pair of electrodes arranged side by side in a first direction; a connecting sheet portion made of a sheet-like carbon nanotube molded body extending in the first direction and a second direction perpendicular to the first direction and connecting the pair of electrodes, which generates heat when power is supplied; an additional conductive portion laminated on the connecting sheet portion in an arrangement region including the region of the periphery of a through hole provided in the connecting sheet portion that intersects with a first virtual straight line extending in the first direction through the center of the through hole, and which has a higher conductivity in the second direction than the connecting sheet portion; and a sheet-like covering portion covering the connecting sheet portion and the additional conductive portion from both sides in a third direction perpendicular to the first direction and the second direction.

[0007] Aspect 2 of the present invention is a carbon nanotube heater according to aspect 1, wherein the arrangement region of the additional conductive portion includes all of the region on the periphery of the through hole that is located on both sides of the first virtual line with respect to the second direction and between a pair of second virtual lines that are parallel to the first virtual line. The pair of second virtual lines are equidistant from the first virtual line with respect to the second direction. The distance between the pair of second virtual lines in the second direction is half the maximum length of the through hole in the second direction.

[0008] A third aspect of the present invention is the carbon nanotube heater according to aspect 2, wherein the arrangement region of the additional conductive portion includes the peripheral edge of the through hole over its entire circumference.

[0009] Aspect 4 of the present invention is a carbon nanotube heater according to any one of aspects 1 to 3, wherein the orientation of the carbon nanotubes in the connecting sheet portion is parallel to the first direction.

[0010] Aspect 5 of the present invention is a carbon nanotube heater according to any one of aspects 1 to 3 (or any one of aspects 1 to 4), wherein the additional conductive part is a metal foil or a metal plate.

[0011] Aspect 6 of the present invention is a carbon nanotube heater according to any one of aspects 1 to 3 (or any one of aspects 1 to 5), wherein the additional conductive portion is a sheet-shaped carbon nanotube molded body in which the orientation of the carbon nanotubes is different from that of the connecting sheet portion.

[0012] Aspect 7 of the present invention is a carbon nanotube heater according to aspect 6, wherein the orientation of the carbon nanotubes in the connecting sheet portion is parallel to the first direction. The orientation of the carbon nanotubes in the additional conductive portion is in a direction inclined with respect to the first direction.

[0013] Aspect 8 of the present invention is a carbon nanotube heater according to aspect 7, wherein the orientation of the carbon nanotubes in the additional conductive portion is parallel to the second direction.

[0014] Aspect 9 of the present invention is a carbon nanotube heater according to aspect 6 (or any one of aspects 6 to 8), wherein the additional conductive portion is provided along the entire length of the connecting sheet portion in the second direction and has other through holes that overlap with the through holes.

[0015] Aspect 10 of the present invention is a carbon nanotube heater according to any one of aspects 1 to 3 (or any one of aspects 1 to 9), wherein the connecting sheet portion, the additional conductive portion, and the coating portion are flexible. [Effects of the Invention]

[0016] This invention makes it possible to improve temperature uniformity around the through hole. [Brief explanation of the drawing]

[0017] [Figure 1] This is a plan view of a CNT heater according to the first embodiment. [Figure 2] This is a cross-sectional view of a CNT heater. [Figure 3] This is a plan view of a CNT heater. [Figure 4] It is a diagram showing the temperature distribution in the CNT heater of the comparative example. [Figure 5] It is a diagram showing the temperature distribution in the CNT heater of the example. [Figure 6] It is a diagram schematically showing the flow of current in the CNT heater of the comparative example. [Figure 7] It is a diagram schematically showing the flow of current in the CNT heater of the example. [Figure 8] It is a plan view of the CNT heater. [Figure 9] It is a plan view of the CNT heater according to the second embodiment. [Figure 10] It is a cross-sectional view of the CNT heater. [Figure 11] It is a diagram showing the temperature distribution in the CNT heater of the example.

Mode for Carrying Out the Invention

[0018] FIG. 1 is a plan view showing a carbon nanotube heater 1 (hereinafter, also referred to as "CNT heater 1") according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of the CNT heater 1 cut at the position II-II in FIG. 1. In FIG. 2, for easy understanding of the drawing, each component of the CNT heater 1 is drawn spaced apart in the vertical direction in the drawing. The CNT heater 1 is, for example, a relatively thin sheet-like heater used for heating an object.

[0019] In FIGS. 1 and 2, three mutually orthogonal directions are indicated by arrows as the X direction, the Y direction, and the Z direction. In the example shown in FIGS. 1 and 2, the X direction and the Y direction are horizontal directions perpendicular to each other, and the Z direction is the vertical direction. The same applies to other figures. In the following description, the X direction, the Y direction, and the Z direction are also referred to as the "first direction", the "second direction", and the "third direction", respectively. When the CNT heater 1 is actually used, the Z direction does not necessarily coincide with the gravitational direction (i.e., the vertical direction).

[0020] In the example shown in Figure 1, the shape of the CNT heater 1 in plan view (i.e., the shape of the CNT heater 1 when viewed along the Z direction) is a roughly rectangular shape with each side roughly parallel to the X or Y direction. The shape of the CNT heater 1 in plan view is not limited to a rectangle and can be changed in various ways, such as a square, trapezoid, or circle.

[0021] The CNT heater 1 comprises a carbon nanotube device 2 (hereinafter also referred to as "CNT device 2") and a coating portion 3. In the example shown in Figure 1, the shape of the CNT device 2 and the coating portion 3 in plan view is also a roughly rectangular shape with each side substantially parallel to the X or Y direction. The shape of the CNT device 2 and the coating portion 3 in plan view is not limited to a rectangle, but can be changed in various ways, such as a square, trapezoid, or circle.

[0022] The CNT device 2 is a substantially sheet-like heating element that generates heat when power is supplied to it. In this specification, "sheet-like" means a shape in which the thickness in the Z direction is thin relative to the size in the X and Y directions, and it may or may not be flexible. Specifically, the sheet-like member may or may not be deformable by human force. Furthermore, in this specification, "sheet-like" is a concept that also includes shapes called "film-like" and shapes called "flat plate-like".

[0023] The CNT device 2 comprises a connecting sheet portion 21, a pair of electrodes 22, and an additional conductive portion 23. The pair of electrodes 22 are arranged side by side in the X direction (i.e., the first direction) and are substantially parallel to each other. The pair of electrodes 22 are arranged at substantially the same position with respect to the Y direction (i.e., the second direction) and face each other while being spaced apart in the X direction. In the example shown in Figure 1, the shape of each electrode 22 in plan view is a substantially rectangular strip extending substantially parallel to the Y direction. The pair of electrodes 22 are sheet-like conductive members having substantially the same shape. Each electrode 22 is, for example, a metal foil made of copper (Cu). The thickness of each electrode 22 is, for example, 20 μm to 300 μm, preferably 40 μm to 100 μm. The material, shape, and size of each electrode 22 can be varied.

[0024] The connecting sheet portion 21 is a sheet-like member that extends in the X and Y directions (i.e., substantially perpendicular to the Z direction) between the pair of electrodes 22, connecting the pair of electrodes 22. In the example shown in Figure 1, the shape of the connecting sheet portion 21 in plan view is a substantially rectangle with each side substantially parallel to the X or Y direction. In Figure 1, parallel diagonal lines are drawn on the connecting sheet portion 21 to facilitate understanding of the figure. In addition, different parallel diagonal lines are drawn on the additional conductive portion 23. Two types of parallel diagonal lines are drawn in the region where the connecting sheet portion 21 and the additional conductive portion 23 overlap.

[0025] The size of the connecting sheet portion 21 varies depending on the performance required of the CNT heater 1. The length of the connecting sheet portion 21 in the X direction is, for example, 30 mm to 500 mm. The length of the connecting sheet portion 21 in the Y direction is, for example, 30 mm to 1000 mm. The size and shape of the connecting sheet portion 21 in plan view can be changed in various ways.

[0026] The connecting sheet portion 21 is composed of a sheet-like carbon nanotube molded body (hereinafter also referred to as "CNT molded body") formed from a large number of carbon nanotubes. The connecting sheet portion 21 is conductive and electrically connects the pair of electrodes 22. In the example shown in Figures 1 and 2, the connecting sheet portion 21 is a laminated sheet-like member in which multiple carbon nanotube sheets are stacked in the Z direction. That is, the Z direction is the thickness direction of the connecting sheet portion 21 and the stacking direction of the multiple carbon nanotube sheets (hereinafter also referred to as "CNT sheets").

[0027] The number of layers of CNT sheets in the connecting sheet section 21 is, for example, 5 to 400 layers. The number of layers of CNT sheets in the connecting sheet section 21 is, for example, approximately the same across almost the entire surface of the connecting sheet section 21, and the thickness of the connecting sheet section 21 is approximately the same across almost the entire surface of the connecting sheet section 21. However, the number of layers of CNT sheets in the connecting sheet section 21 is not limited to the above range and may be varied in a range of 1 or more layers. Also, the thickness of the connecting sheet section 21 does not necessarily have to be approximately the same across almost the entire surface and may differ from part to part.

[0028] The orientation of the carbon nanotubes in the connecting sheet portion 21 (i.e., the direction in which the carbon nanotubes extend) is approximately parallel to the X direction. In other words, in the multiple layers of CNT sheets that constitute the connecting sheet portion 21, the numerous carbon nanotubes constituting each CNT sheet extend approximately parallel to the X direction (i.e., the first direction).

[0029] The X-direction ends of the connecting sheet portion 21 are fixed to a pair of electrodes 22. For example, the electrodes 22 are folded and pressed with the ends of the connecting sheet portion 21 sandwiched between them, thereby fixing the connecting sheet portion 21 and the electrodes 22. Alternatively, the ends of the connecting sheet portion 21 located on the electrodes 22 may be covered with metal foil, and the connecting sheet portion 21 may be fixed to the electrodes 22 by joining the metal foil to the electrodes 22. The connecting sheet portion 21 may be fixed to the electrodes 22 by methods other than those described above.

[0030] Each electrode 22 is connected to the connecting sheet portion 21 at its X-direction end, extending along its entire length in the Y-direction. In the example shown in Figure 1, the (+Y) end of each electrode 22 extends slightly to the (+Y) side from the (+Y) edge of the connecting sheet portion 21. The (-Y) end of each electrode 22 extends relatively far to the (-Y) side from the (-Y) edge of the connecting sheet portion 21 and protrudes in the (-Y) direction from the (-Y) edge of the covering portion 3. The portion of each electrode 22 that protrudes from the covering portion 3 in the (-Y) direction becomes a terminal for supplying power to the CNT heater 1. Power is supplied to the connecting sheet portion 21 via these terminals of the pair of electrodes 22, causing the connecting sheet portion 21 to heat up.

[0031] The connecting sheet portion 21 is provided with a through hole 211 that penetrates the connecting sheet portion 21 in the Z direction (i.e., the thickness direction). In the example shown in Figure 1, the shape of the through hole 211 in plan view is approximately circular and it is located approximately in the center of the connecting sheet portion 21 in the X and Y directions. The maximum length of the through hole 211 in the X direction (diameter in the example shown in Figure 1) is, for example, 1.2% to 50% of the maximum length of the connecting sheet portion 21 in the X direction. The maximum length of the through hole 211 in the Y direction (diameter in the example shown in Figure 1) is, for example, 0.6% to 50% of the maximum length of the connecting sheet portion 21 in the Y direction. The shape, size, and position of the through hole 211 on the connecting sheet portion 21 can be varied.

[0032] The additional conductive portion 23 is a conductive sheet-like member laminated on the connecting sheet portion 21 at the periphery of the through hole 211 of the connecting sheet portion 21. In the example shown in Figure 1, the additional conductive portion 23 is a substantially annular member provided along the periphery of the through hole 211 over almost the entire circumference. Specifically, the shape of the additional conductive portion 23 in plan view is a substantially annular shape provided over the entire circumference of the periphery of the through hole 211. The center of the additional conductive portion 23 substantially coincides with the center of the through hole 211.

[0033] In the examples shown in Figures 1 and 2, the additional conductive portion 23 is provided on the main surface of the connecting sheet portion 21 on the (+Z) side. The additional conductive portion 23 may also be provided on the main surface of the connecting sheet portion 21 on the (-Z) side, or on the main surfaces of the connecting sheet portion 21 on both the (+Z) and (-Z) sides.

[0034] In the example shown in Figure 1, the inner periphery of the additional conductive portion 23 overlaps with the periphery of the through hole 211 of the connecting sheet portion 21 over almost the entire circumference in a plan view. In other words, the inner diameter of the additional conductive portion 23 (i.e., the diameter of the inner periphery) is approximately the same as the diameter of the through hole 211 of the connecting sheet portion 21. The outer diameter of the additional conductive portion 23 (i.e., the diameter of the outer periphery) is larger than the diameter of the through hole 211 of the connecting sheet portion 21. The radial width of the additional conductive portion 23 (i.e., the difference between the outer diameter and the inner diameter) is, for example, 1% to 30% of the diameter of the through hole 211. Note that the inner diameter of the additional conductive portion 23 may be smaller or larger than the diameter of the through hole 211 of the connecting sheet portion 21.

[0035] The additional conductive portion 23 is, for example, a metal foil or metal plate made of stainless steel or the like. The thickness of the additional conductive portion 23 is, for example, 5 μm to 200 μm, and is substantially the same across almost the entire surface of the additional conductive portion 23. The conductivity of the additional conductive portion 23 is higher than the conductivity of the connecting sheet portion 21. Specifically, the conductivity of the additional conductive portion 23 in the Y direction is higher than the conductivity of the connecting sheet portion 21 in the Y direction, and the conductivity of the additional conductive portion 23 in the X direction is higher than the conductivity of the connecting sheet portion 21 in the X direction.

[0036] Furthermore, the conductivity of the additional conductive portion 23 only needs to be higher than that of the connecting sheet portion 21, at least in the Y direction. That is, the conductivity of the additional conductive portion 23 in the X direction may be the same as, or lower than, that of the connecting sheet portion 21 in the X direction. In addition, the additional conductive portion 23 does not necessarily have to be made of metal; for example, it may be formed from a conductive resin film or conductive ceramics.

[0037] The covering portion 3 is a sheet-like member that covers substantially the entire surface of the connecting sheet portion 21 and the additional conductive portion 23 from both sides in the Z direction. The covering portion 3 also covers the parts of the pair of electrodes 22, excluding the (-Y) end, from both sides in the Z direction. In the example shown in Figure 2, the covering portion 3 comprises a first covering portion 31 that contacts the main surface of the connecting sheet portion 21 on the (+Z) side, and a second covering portion 32 that contacts the main surface of the connecting sheet portion 21 on the (-Z) side. The first covering portion 31 and the second covering portion 32 are joined to each other by an adhesive or the like around the connecting sheet portion 21 and the pair of electrodes 22, with the connecting sheet portion 21, the pair of electrodes 22, and the additional conductive portion 23 sandwiched between them. The covering portion 3 may also be a single sheet member folded in half.

[0038] The covering portion 3 (i.e., the first covering portion 31 and the second covering portion 32) is an insulator with lower conductivity than the connecting sheet portion 21, each electrode 22, and the additional conductive portion 23. The covering portion 3 is, for example, a resin sheet formed from a resin such as polyimide. The covering portion 3 is, for example, a transparent or translucent material. In the example shown in Figure 1, the covering portion 3 is flexible. The connecting sheet portion 21 and the additional conductive portion 23 are also flexible. Therefore, the CNT heater 1 is flexible.

[0039] The covering portion 3 has a through hole 33 that overlaps with the through hole 211 of the connecting sheet portion 21 in a plan view. In the following description, the through hole 211 of the connecting sheet portion 21 will also be referred to as the "first through hole 211," and the through hole 33 of the covering portion 3 will also be referred to as the "second through hole 33." The second through hole 33 penetrates the first covering portion 31 and the second covering portion 32 of the covering portion 3 in the Z direction (i.e., the thickness direction). In the example shown in Figure 1, the shape of the second through hole 33 in a plan view is approximately circular.

[0040] In a plan view, the size of the second through-hole 33 is less than or equal to the size of the first through-hole 211, and preferably, the second through-hole 33 is smaller than the first through-hole 211. That is, in a plan view, the periphery of the second through-hole 33 overlaps with the periphery of the first through-hole 211 or is located radially inward from the periphery of the first through-hole 211. In the example shown in Figure 1, the periphery of the second through-hole 33 is radially separated inward from the periphery of the first through-hole 211 along its entire circumference, and in a plan view, the entirety of the second through-hole 33 is contained within the first through-hole 211. The diameter of the second through-hole 33 is, for example, 20% to 100% of the diameter of the first through-hole 211, preferably 40% to 60%. The center of the second through-hole 33 substantially coincides with the center of the first through-hole 211. The shape, size, and position of the second through-hole 33 on the connecting sheet portion 21 may be changed in various ways to match the first through-hole 211.

[0041] Next, examples and comparative examples of the CNT heater 1 will be described with reference to Table 1. In Examples 1 to 4, power was supplied between the pair of electrodes 22 in the CNT heater 1 described above, and after the temperature of the connecting sheet portion 21 stabilized, the temperatures T1 and T2 at the positions indicated by rectangles labeled P1 and P2 in Figure 3 were measured. In Comparative Examples 1 to 4, comparative CNT heaters were used, which were the same as the CNT heater 1 described above but without the additional conductive portion 23, and the temperatures T1 and T2 were measured in substantially the same manner as in Examples 1 to 4. Temperatures T1 and T2 were measured using a thermograph manufactured by Optex FA Co., Ltd. In Examples 1 to 4 and Comparative Examples 1 to 4, the current flowing between the pair of electrodes 22 was changed.

[0042] [Table 1]

[0043] In Examples 1-4 and Comparative Examples 1-4, the shape of the connecting sheet portion 21 in plan view is approximately rectangular, with lengths of 100 mm and 60 mm in the X and Y directions, respectively. The number of layers of CNT sheets in the connecting sheet portion 21 is 40. The first through hole 211 is located approximately in the center of the connecting sheet portion 21 in the X and Y directions. The shape of the first through hole 211 in plan view is approximately circular with a diameter of 15 mm. The pair of electrodes 22 are metal foils made of Cu. The covering portion 3 is a resin sheet made of polyimide. The shape of the second through hole 33 in plan view is approximately circular with a diameter of 10 mm. The center of the second through hole 33 approximately coincides with the center of the first through hole 211.

[0044] In Examples 1 to 4, the shape of the additional conductive portion 23 in plan view is approximately annular, with inner and outer diameters of 13 mm and 19 mm, respectively. The center of the additional conductive portion 23 approximately coincides with the center of the first through hole 211. The additional conductive portion 23 is a 50 μm thick metal foil made of stainless steel.

[0045] In Examples 1-4 and Comparative Examples 1-4, the above-mentioned position P1 is located at the center of the connecting sheet portion 21 in the X direction, 6.5 mm away from the (+Y) side end of the periphery of the first through hole 211. Position P2 is located at the center of the connecting sheet portion 21 in the Y direction, 6.5 mm away from the (-X) side end of the periphery of the first through hole 211.

[0046] In Comparative Example 1, the current flowing between the pair of electrodes 22 was 0.9A. The temperature T1 of the CNT heater 1 at position P1 was 224.5°C. The temperature T2 of the CNT heater 1 at position P2 was 100.9°C. The absolute value of the difference between temperature T1 and temperature T2 (hereinafter also referred to as "temperature difference ΔT") was 123.6°C. Figure 4 shows the temperature distribution in the CNT heater 1 of Comparative Example 1. In Figure 4, the whitish areas in the region corresponding to the connecting sheet portion 21 are high-temperature areas, and the dark areas are low-temperature areas (the same applies to Figures 5 and 11).

[0047] In Comparative Example 2, the current flowing between the pair of electrodes 22 was 0.8A. The temperature T1 of the CNT heater 1 at position P1 was 186.5°C. The temperature T2 of the CNT heater 1 at position P2 was 75.5°C. The temperature difference ΔT was 111.0°C.

[0048] In Comparative Example 3, the current flowing between the pair of electrodes 22 was 0.5A. The temperature T1 of the CNT heater 1 at position P1 was 102.8°C. The temperature T2 of the CNT heater 1 at position P2 was 51.9°C. The temperature difference ΔT was 50.9°C.

[0049] In Comparative Example 4, the current flowing between the pair of electrodes 22 was 0.3A. The temperature T1 of the CNT heater 1 at position P1 was 47.3°C. The temperature T2 of the CNT heater 1 at position P2 was 32.1°C. The temperature difference ΔT was 15.2°C.

[0050] In Example 1, the current flowing between the pair of electrodes 22 was 1.0 A. The temperature T1 of the CNT heater 1 at position P1 was 139.3°C. The temperature T2 of the CNT heater 1 at position P2 was 203.8°C. The temperature difference ΔT was 64.5°C. Figure 5 shows the temperature distribution in the CNT heater 1 of Example 1.

[0051] In Example 2, the current flowing between the pair of electrodes 22 was 0.8A. The temperature T1 of the CNT heater 1 at position P1 was 102.9°C. The temperature T2 of the CNT heater 1 at position P2 was 131.4°C. The temperature difference ΔT was 28.5°C.

[0052] In Example 3, the current flowing between the pair of electrodes 22 was 0.6A. The temperature T1 of the CNT heater 1 at position P1 was 80.4°C. The temperature T2 of the CNT heater 1 at position P2 was 96.3°C. The temperature difference ΔT was 15.9°C.

[0053] In Example 4, the current flowing between the pair of electrodes 22 was 0.3A. The temperature T1 of the CNT heater 1 at position P1 was 43.1°C. The temperature T2 of the CNT heater 1 at position P2 was 44.6°C. The temperature difference ΔT was 1.5°C.

[0054] In Comparative Examples 1 to 4, as schematically shown by the arrows in Figure 6, the current flowing between the pair of electrodes 22 avoids the first through-hole 211 of the connecting sheet portion 21 and flows toward the sides of the first through-hole 211 (i.e., the (+Y) side and the (-Y) side), concentrating in the region adjacent to the first through-hole 211 on the side of the first through-hole 211. Therefore, current is less likely to flow in the region around the first through-hole 211 that faces the pair of electrodes 22 (i.e., the areas near the (+X) side and (-X) side ends of the first through-hole 211). Consequently, the temperature difference (i.e., the temperature difference ΔT mentioned above) between the areas near the (+Y) side and (-Y) side ends of the first through-hole 211 and the areas near the (+X) side and (-X) side ends of the first through-hole 211 becomes large.

[0055] On the other hand, in Examples 1 to 4, the addition of the conductive portion 23 around the first through-hole 211 increases the conductivity in the Y direction in the areas near the (+X) and (-X) ends of the first through-hole 211. As a result, as schematically shown by the arrows in Figure 7, the current flowing through the connecting sheet portion 21 between the pair of electrodes 22 approaches the first through-hole 211 relatively close to it without avoiding it. Therefore, current flows more easily in the area around the first through-hole 211 that faces the pair of electrodes 22 (i.e., the areas near the (+X) and (-X) ends of the first through-hole 211). Consequently, the temperature difference (i.e., temperature difference ΔT) between the areas near the (+Y) and (-Y) ends of the first through-hole 211 and the areas near the (+X) and (-X) ends of the first through-hole 211 becomes smaller.

[0056] Specifically, comparing Comparative Example 1 and Example 1, where the current values ​​flowing between the pair of electrodes 22 are approximately the same, the temperature difference ΔT in Comparative Example 1 is large at 123.6°C, while the temperature difference ΔT in Example 1 is small at 64.5°C. Similarly, the temperature difference ΔT in Comparative Example 2 is large at 111.0°C, while the temperature difference ΔT in Example 2 is small at 28.5°C. The temperature difference ΔT in Comparative Example 3 is large at 50.9°C, while the temperature difference ΔT in Example 3 is small at 15.9°C. The temperature difference ΔT in Comparative Example 4 is large at 15.2°C, while the temperature difference ΔT in Example 4 is small at 1.5°C. Therefore, in Examples 1 to 4, the uniformity of the temperature of the CNT heater 1 around the first through-hole 211 is improved compared to Comparative Examples 1 to 4.

[0057] In the CNT heater 1 illustrated in Figure 1, the additional conductive portion 23 is provided around the entire circumference of the first through-hole 211, but it is not limited to this, and may be provided only in a part of the circumference of the first through-hole 211. For example, in the CNT heater 1a shown in Figure 8, two additional conductive portions 23a, each substantially arc-shaped, are arranged around the first through-hole 211 in areas excluding the vicinity of the (+Y) side end and the vicinity of the (-Y) side end of the first through-hole 211.

[0058] The area where the additional conductive portion 23a is located includes at least the region C1 of the periphery of the first through-hole 211 that intersects with the first virtual line L1 extending in the X direction through the center C0 of the first through-hole 211. In Figure 8, region C1 is enclosed by a dashed line. Preferably, the area where the additional conductive portion 23a is located includes the periphery of the first through-hole 211 that extends 30° circumferentially on both the (+Y) side and the (-Y) side of region C1. In other words, preferably, the area where the additional conductive portion 23a is located includes all of the region of the periphery of the first through-hole 211 that is located on both sides of the first virtual line L1 with respect to the Y direction and between a pair of second virtual lines L2 that are parallel to the first virtual line L1. In other words, it is preferable that the additional conductive portion 23a is provided in the entire region of the periphery of the first through-hole 211 that extends from one of the pair of second virtual lines L2 to the other. The pair of second virtual lines L2 are equidistant from the first virtual line L1 with respect to the Y direction. The distance between the pair of second virtual lines L2 in the Y direction is half the maximum length of the first through hole 211 in the Y direction (i.e., the diameter of the first through hole 211). If the shape of the first through hole 211 in plan view is not circular, the center C0 of the first through hole 211 refers to the centroid of the first through hole 211 in plan view.

[0059] As described above, the CNT heaters 1 and 1a comprise a pair of electrodes 22, a connecting sheet portion 21, additional conductive portions 23 and 23a, and a covering portion 3. The pair of electrodes 22 are arranged side by side in a first direction (i.e., the X direction). The connecting sheet portion 21 is made of a sheet-shaped CNT molded body. The connecting sheet portion 21 extends in the X direction and in a second direction perpendicular to the X direction (i.e., the Y direction), connecting the pair of electrodes 22. The connecting sheet portion 21 generates heat when power is supplied to it. The additional conductive portions 23 and 23a are laminated on the connecting sheet portion 21 in an arrangement region that includes a region C1 that intersects with a first virtual straight line L1 extending in the X direction through the center C0 of the first through hole 211, among the peripheral edges of the through hole 211 provided in the connecting sheet portion 21. The conductivity of the additional conductive portions 23 and 23a in the Y direction is higher than the conductivity of the connecting sheet portion 21 in the Y direction. The covering portion 3 is a sheet-like member. The covering portion 3 covers the connecting sheet portion 21 and the additional conductive portions 23, 23a from both sides in a third direction (i.e., the Z direction) perpendicular to the X and Y directions.

[0060] This makes it easier for current to flow in the connecting sheet portion 21 to the vicinity of the part of the periphery of the first through hole 211 that faces the pair of electrodes 22 in the X direction (i.e., the first direction). As a result, the uniformity of the temperature of the CNT heaters 1,1a around the first through hole 211 (i.e., uniform heating) can be improved.

[0061] As described above, it is preferable that the arrangement region of the additional conductive parts 23, 23a includes the entire region of the periphery of the first through hole 211 that is located between a pair of second virtual lines L2. The pair of second virtual lines L2 are located on both sides of the first virtual line L1 with respect to the Y direction. The pair of second virtual lines L2 are parallel to the first virtual line L1. The pair of second virtual lines L2 are equidistant from the first virtual line L1 with respect to the Y direction. The distance between the pair of second virtual lines L2 in the Y direction is half the maximum length of the first through hole 211 in the Y direction (in the above example, the diameter of the first through hole 211).

[0062] In this way, by providing additional conductive portions 23, 23a around the first through-hole 211 in a relatively close and relatively wide area relative to the pair of electrodes 22, the uniformity of the temperature of the CNT heaters 1, 1a around the first through-hole 211 can be further improved.

[0063] As described above, it is preferable that the area in which the additional conductive portion 23 is arranged includes the entire periphery of the first through-hole 211. This further improves the uniformity of the temperature of the CNT heater 1 around the first through-hole 211.

[0064] As described above, it is preferable that the orientation of the carbon nanotubes in the connecting sheet portion 21 is parallel to the X direction. This makes it possible to reduce the resistance of the connecting sheet portion 21 between the pair of electrodes 22.

[0065] As described above, the additional conductive parts 23 and 23a are preferably metal foils or metal plates. This makes it easy to provide the additional conductive parts 23 and 23a on the connecting sheet 21. Furthermore, if the additional conductive part 23 is a metal foil or metal plate provided around the entire circumference of the first through hole 211, the strength of the CNT heater 1 in the area surrounding the first through hole 211 can be increased.

[0066] As described above, it is preferable that the connecting sheet portion 21, the additional conductive portions 23, 23a, and the covering portion 3 are flexible. This allows the CNT heaters 1, 1a to be easily deformed to suit the installation location, thereby increasing the flexibility of the installation location of the CNT heaters 1, 1a.

[0067] In CNT heaters 1 and 1a, the additional conductive parts 23 and 23a may be sheet-shaped CNT molded bodies in which the orientation of carbon nanotubes differs from that of the connecting sheet part 21. This allows the connecting sheet part 21 and the additional conductive parts 23 and 23a to be formed from the same material, thereby simplifying the manufacturing of CNT heaters 1 and 1a. For example, the additional conductive parts 23 and 23a may be laminated sheet-shaped CNT molded bodies in which multiple CNT sheets are stacked.

[0068] When the additional conductive portions 23 and 23a are CNT molded bodies, it is preferable that the orientation of the carbon nanotubes in the connecting sheet portion 21 is parallel to the X direction, and the orientation of the carbon nanotubes in the additional conductive portions 23 and 23a is inclined with respect to the X direction. This makes it possible to reduce the resistance of the connecting sheet portion 21 between the pair of electrodes 22, and to suitably make the conductivity of the additional conductive portions 23 and 23a in the Y direction higher than the conductivity of the connecting sheet portion 21 in the Y direction. As a result, the uniformity of the temperature of the CNT heaters 1 and 1a around the first through-hole 211 can be suitably improved.

[0069] More preferably, the orientation of the carbon nanotubes in the additional conductive portions 23, 23a is parallel to the Y direction (i.e., perpendicular to the X direction). This makes it possible to increase the difference between the conductivity of the additional conductive portions 23, 23a in the Y direction and the conductivity of the connecting sheet portion 21 in the Y direction. As a result, the uniformity of the temperature of the CNT heaters 1, 1a around the first through-hole 211 can be further improved.

[0070] Next, a CNT heater 1b according to a second embodiment of the present invention will be described. Figure 9 is a plan view showing the CNT heater 1b. Figure 10 is a cross-sectional view of the CNT heater 1b cut at position XX in Figure 9. In the CNT heater 1b, an additional conductive part 23b, which has a different shape from the additional conductive part 23 shown in Figure 1, is provided instead. The other components of the CNT heater 1b are substantially the same as those of the CNT heater 1, and in the following description, the same reference numerals are used for components of the CNT heater 1 and the corresponding components of the CNT heater 1b.

[0071] In Figure 9, to facilitate understanding of the diagram, parallel diagonal lines are drawn on the connecting sheet portion 21, similar to Figure 1, and different parallel diagonal lines are drawn on the additional conductive portion 23b. Two types of parallel diagonal lines are drawn in the region where the connecting sheet portion 21 and the additional conductive portion 23b overlap. In Figure 10, to facilitate understanding of the diagram, the components of the CNT heater 1b are drawn spaced apart vertically within the diagram.

[0072] The additional conductive portion 23b is a sheet-like member that is laminated on the connecting sheet portion 21 at the center of the connecting sheet portion 21 in the X direction. The additional conductive portion 23b is composed of a sheet-like CNT molded body formed from a large number of carbon nanotubes. In the examples shown in Figures 9 and 10, the additional conductive portion 23b is a laminated sheet-like member in which multiple carbon nanotube sheets are laminated in the Z direction.

[0073] In the example shown in Figure 9, the shape of the additional conductive portion 23b in plan view is a substantially rectangular shape with one pair of sides substantially parallel to the X direction and the other pair of sides substantially parallel to the Y direction. The additional conductive portion 23b is provided over substantially the entire length of the connecting sheet portion 21 in the Y direction. The length of the additional conductive portion 23b in the Y direction is substantially the same as the length of the connecting sheet portion 21 in the Y direction. That is, the (+Y) side and (-Y) side edges of the additional conductive portion 23b substantially overlap with the (+Y) side and (-Y) side edges of the connecting sheet portion 21 in plan view.

[0074] The length of the additional conductive portion 23b in the X direction is greater than the maximum length (i.e., diameter) of the first through hole 211 in the X direction. The first through hole 211 is located between the (+X) side and the (-X) side edges of the additional conductive portion 23b. In other words, the (+X) side edge of the additional conductive portion 23b is spaced away from the first through hole 211 towards the (+X) side, and the (-X) side edge of the additional conductive portion 23b is spaced away from the first through hole 211 towards the (-X) side. The length of the additional conductive portion 23b in the X direction is less than the length of the connecting sheet portion 21 in the X direction. For example, the length of the additional conductive portion 23b in the X direction is 2.4% to 55% of the length of the connecting sheet portion 21 in the X direction. The size and shape of the additional conductive portion 23b in plan view can be varied.

[0075] The additional conductive portion 23b includes a through-hole 231 that overlaps with the first through-hole 211 of the connecting sheet portion 21 in a plan view. In the following description, the through-hole 231 of the additional conductive portion 23b will also be referred to as the "third through-hole 231". The third through-hole 231 penetrates the additional conductive portion 23b in the Z direction (i.e., the thickness direction). The third through-hole 231 is located approximately in the center of the additional conductive portion 23b in the X and Y directions, for example. In the example shown in Figure 9, the shape of the third through-hole 231 in a plan view is approximately circular.

[0076] In the example shown in Figure 9, the size of the third through-hole 231 in plan view is approximately the same as the size of the first through-hole 211 in plan view. The center of the third through-hole 231 approximately coincides with the center of the first through-hole 211. That is, the periphery of the third through-hole 231 overlaps with the periphery of the first through-hole 211 in plan view. Furthermore, the periphery of the third through-hole 231 is spaced radially outward from the periphery of the second through-hole 33 of the covering portion 3 along its entire circumference. Note that the shape, size, and position of the third through-hole 231 on the additional conductive portion 23b may be changed in various ways to match the first through-hole 211. Also, the third through-hole 231 does not necessarily have to be the same size as the first through-hole 211, and the periphery of the third through-hole 231 may be located radially inward or radially outward from the periphery of the first through-hole 211.

[0077] The number of layers of CNT sheets in the additional conductive portion 23b is, for example, 3 to 100 layers. The number of layers of CNT sheets in the additional conductive portion 23b is, for example, approximately the same over substantially the entire surface of the additional conductive portion 23b, and the thickness of the additional conductive portion 23b is approximately the same over substantially the entire surface of the additional conductive portion 23b. However, the number of layers of CNT sheets in the additional conductive portion 23b is not limited to this range and may be varied in a range of 1 or more layers. Also, the thickness of the additional conductive portion 23b does not necessarily have to be approximately the same over substantially the entire surface and may differ from part to part.

[0078] The orientation of the carbon nanotubes in the additional conductive portion 23b (i.e., the direction in which the carbon nanotubes extend) is in a direction inclined with respect to the orientation of the carbon nanotubes in the connecting sheet portion 21. As described above, when the orientation of the carbon nanotubes in the connecting sheet portion 21 is approximately parallel to the X direction, the orientation of the carbon nanotubes in the additional conductive portion 23b is in a direction inclined with respect to the X direction. In the examples shown in Figures 9 and 10, the orientation of the carbon nanotubes in the additional conductive portion 23b is approximately parallel to the Y direction (i.e., approximately perpendicular to the X direction).

[0079] The additional conductive portion 23b is conductive, and its conductivity in the Y direction is higher than that of the connecting sheet portion 21 in the Y direction. On the other hand, the conductivity of the additional conductive portion 23b in the X direction is lower than that of the connecting sheet portion 21 in the X direction. As a result, similar to the CNT heaters 1 and 1a described above, current flows relatively easily in the region around the first through-hole 211 that faces the pair of electrodes 22 (i.e., the areas near the (+X) and (-X) ends of the first through-hole 211), thereby improving the uniformity of the temperature of the CNT heater 1b around the first through-hole 211.

[0080] Next, examples of the CNT heater 1b will be described with reference to Table 2. In Examples 5 to 7, power was supplied between the pair of electrodes 22 in the CNT heater 1b described above, and after the temperature of the connecting sheet portion 21 stabilized, the temperatures T1 and T2 at the above-mentioned positions P1 and P2 (see Figure 3) were measured. In Examples 5 to 7, the current flowing between the pair of electrodes 22 was changed. Table 2 also shows the above-mentioned Comparative Examples 1 to 3.

[0081] [Table 2]

[0082] In Examples 5 to 7, the structure and size of the connecting sheet portion 21, as well as the positions P1 and P2 on the connecting sheet portion 21, are the same as in Examples 1 to 4 described above. Furthermore, the structure and size of the pair of electrodes 22 and the covering portion 3 are also the same as in Examples 1 to 4.

[0083] In Examples 5 to 7, the shape of the additional conductive portion 23b in plan view is approximately rectangular, with lengths of 40 mm and 60 mm in the X and Y directions, respectively. The number of layers of CNT sheets in the additional conductive portion 23b is 40. The third through hole 231 is the same size as the first through hole 211, and the periphery of the third through hole 231 approximately coincides with the periphery of the first through hole 211 in plan view.

[0084] In Example 5, the current flowing between the pair of electrodes 22 was 0.8A. The temperature T1 of the CNT heater 1 at position P1 was 200.8°C. The temperature T2 of the CNT heater 1b at position P2 was 122.8°C. The temperature difference ΔT was 78.0°C. Figure 11 shows the temperature distribution in the CNT heater 1b of Example 5.

[0085] In Example 6, the current flowing between the pair of electrodes 22 was 0.7A. The temperature T1 of the CNT heater 1 at position P1 was 170.2°C. The temperature T2 of the CNT heater 1b at position P2 was 104.6°C. The temperature difference ΔT was 65.6°C.

[0086] In Example 7, the current flowing between the pair of electrodes 22 was 0.5A. The temperature T1 of the CNT heater 1b at position P1 was 132.6°C. The temperature T2 of the CNT heater 1b at position P2 was 83.9°C. The temperature difference ΔT was 48.7°C.

[0087] In Examples 5 to 7, by providing additional conductive portions 23b around the first through-hole 211, the conductivity in the Y direction is increased in the areas near the (+X) and (-X) ends of the first through-hole 211, similar to Examples 1 to 4. As a result, the current flowing between the pair of electrodes 22 approaches the first through-hole 211 without avoiding it, reaching relatively close to it. Consequently, current flows more easily in the area around the first through-hole 211 that faces the pair of electrodes 22. Therefore, the temperature difference (i.e., temperature difference ΔT) between the areas near the (+Y) and (-Y) ends of the first through-hole 211 and the areas near the (+X) and (-X) ends of the first through-hole 211 becomes smaller.

[0088] Specifically, comparing Comparative Example 2 and Example 5, where the current flowing between the pair of electrodes 22 is the same, the temperature difference ΔT in Comparative Example 2 is large at 111.0°C, while the temperature difference ΔT in Example 5 is small at 78.0°C. The temperature difference ΔT in Comparative Example 3 is large at 50.9°C, while the temperature difference ΔT in Example 7 is small at 48.7°C. Therefore, in Examples 5 to 7, the uniformity of the temperature of the CNT heater 1b around the first through-hole 211 is improved compared to Comparative Examples 1 to 3.

[0089] The CNT heater 1b is substantially the same as the CNT heater 1 described above, comprising a pair of electrodes 22, a connecting sheet portion 21, an additional conductive portion 23b, and a covering portion 3. The pair of electrodes 22 are arranged side by side in a first direction (i.e., the X direction). The connecting sheet portion 21 is made of a sheet-shaped CNT molded body. The connecting sheet portion 21 extends in the X direction and in a second direction perpendicular to the X direction (i.e., the Y direction), connecting the pair of electrodes 22. The connecting sheet portion 21 generates heat when power is supplied to it. The additional conductive portion 23b is laminated on the connecting sheet portion 21 in an arrangement region that includes a region C1 (see Figure 8) on the periphery of a through hole (i.e., a first through hole 211) provided in the connecting sheet portion 21, where it intersects with a first virtual straight line L1 extending in the X direction through the center C0 of the first through hole 211. The conductivity of the additional conductive portion 23b in the Y direction is higher than the conductivity of the connecting sheet portion 21 in the Y direction. The covering portion 3 is a sheet-like member. The covering portion 3 covers the connecting sheet portion 21 and the additional conductive portion 23b from both sides in a third direction (i.e., the Z direction) perpendicular to the X and Y directions.

[0090] This makes it easier for current to flow in the connecting sheet portion 21 to the vicinity of the part of the periphery of the first through hole 211 that faces the pair of electrodes 22 in the X direction (i.e., the first direction). As a result, the uniformity of the temperature of the CNT heater 1b around the first through hole 211 (i.e., uniform heating) can be improved.

[0091] The arrangement region of the additional conductive portion 23b preferably includes the entire region located between a pair of second virtual lines L2 (see Figure 8) on the periphery of the first through hole 211. The pair of second virtual lines L2 are located on both sides of the first virtual line L1 (see Figure 8) with respect to the Y direction. The pair of second virtual lines L2 are parallel to the first virtual line L1. The pair of second virtual lines L2 are equidistant from the first virtual line L1 with respect to the Y direction. The distance between the pair of second virtual lines L2 in the Y direction is half the maximum length of the first through hole 211 in the Y direction (in the above example, the diameter of the first through hole 211).

[0092] In this way, by providing the additional conductive portion 23b around the first through-hole 211 in a relatively close and relatively wide area relative to the pair of electrodes 22, the uniformity of the temperature of the CNT heater 1b around the first through-hole 211 can be further improved.

[0093] The arrangement region of the additional conductive portion 23b preferably includes the entire periphery of the first through-hole 211. This further improves the uniformity of the temperature of the CNT heater 1b around the first through-hole 211.

[0094] The connecting sheet portion 21, the additional conductive portion 23b, and the covering portion 3 are preferably flexible. This allows the CNT heater 1b to be easily deformed to fit the installation location, thereby increasing the flexibility of the installation location of the CNT heater 1b.

[0095] As described above, in the CNT heater 1b, the additional conductive portion 23b is a sheet-shaped CNT molded body in which the orientation of carbon nanotubes is different from that of the connecting sheet portion 21. This allows the connecting sheet portion 21 and the additional conductive portion 23b to be formed from the same material, thereby simplifying the manufacturing of the CNT heater 1b.

[0096] As described above, it is preferable that the orientation of the carbon nanotubes in the connecting sheet portion 21 is parallel to the X direction. This makes it possible to reduce the resistance of the connecting sheet portion 21 between the pair of electrodes 22. Furthermore, it is preferable that the orientation of the carbon nanotubes in the additional conductive portion 23b is inclined with respect to the X direction. This makes it possible to suitably increase the conductivity of the additional conductive portion 23b in the Y direction compared to the conductivity of the connecting sheet portion 21 in the Y direction. As a result, the uniformity of the temperature of the CNT heater 1b around the first through hole 211 can be suitably improved.

[0097] More preferably, the orientation of the carbon nanotubes in the additional conductive portion 23b is parallel to the Y direction (i.e., perpendicular to the X direction). This makes it possible to increase the difference between the conductivity of the additional conductive portion 23b in the Y direction and the conductivity of the connecting sheet portion 21 in the Y direction. As a result, the uniformity of the temperature of the CNT heater 1b around the first through hole 211 can be further improved.

[0098] Various modifications are possible for the CNT heaters 1, 1a, and 1b described above.

[0099] For example, the additional conductive parts 23 and 23a do not necessarily need to be flexible and may be made of a rigid material. Similarly, the covering part 3 does not necessarily need to be flexible and may be made of a rigid material.

[0100] The pair of electrodes 22 do not necessarily have to be positioned substantially parallel to each other. For example, one electrode 22 may be positioned substantially parallel to the Y direction, while the other electrode 22 is positioned to extend in a direction inclined with respect to the X and Y directions. Furthermore, the shape of each electrode 22 in plan view does not necessarily have to be a rectangular strip; for example, it may be a substantially circular arc centered on the center of the first through-hole 211.

[0101] The shape of the connecting sheet portion 21 in plan view does not necessarily have to be rectangular; for example, it may be approximately circular with the center of the first through hole 211 as the center.

[0102] The shape of the first through-hole 211 of the connecting sheet portion 21 in plan view is not necessarily limited to a circle, but may be, for example, roughly rectangular. The same applies to the second through-hole 33 and the third through-hole 231.

[0103] The orientation of the carbon nanotubes in the connecting sheet portion 21 does not necessarily have to be substantially parallel to the X direction; it may be in a direction inclined with respect to the X direction.

[0104] In the CNT heater 1a, the area where the additional conductive portion 23a is located only needs to include at least the region C1 of the periphery of the first through hole 211 that intersects with the first virtual line L1, and does not necessarily need to include all of the region of the periphery of the first through hole 211 that is located between the pair of second virtual lines L2.

[0105] In the CNT heater 1b, the additional conductive portion 23b does not necessarily have to be provided along the entire length of the connecting sheet portion 21 in the Y direction. For example, the length of the additional conductive portion 23b in the Y direction may be greater than the maximum length (i.e., diameter) of the first through hole 211 in the Y direction, and less than the length of the connecting sheet portion 21 in the Y direction.

[0106] In the CNT heaters 1, 1a, and 1b, for example, the numerous carbon nanotubes constituting the connecting sheet portion 21 may be bonded to each other with an adhesive mainly composed of an aqueous polyvinyl alcohol (PVA) solution. The adhesive may be an epoxy, acrylic, or silicone rubber adhesive. The adhesive may also contain a conductive additive. The conductive additive may be, for example, metal fine particles such as silver (Ag), graphene (specifically, powder obtained by crushing sheet-like graphene), milled fiber, or carbon nanotube powder. The diameter of the conductive additive is preferably 10 μm or less, and more preferably less than 1 μm. Note that the adhesive does not necessarily contain a conductive additive.

[0107] In the CNT heaters 1, 1a, and 1b, for example, a reflective portion may be provided on the (-Z) side of the connecting sheet portion 21 to reflect heat from the connecting sheet portion 21. This reflective portion is, for example, a sheet-like member with a metal foil provided on the main surface of the (+Z) side of the heat insulating sheet. This allows heat from the connecting sheet portion 21 to be efficiently collected on the (+Z) side of the connecting sheet portion 21. Note that the reflective portion may be provided on the (+Z) side of the connecting sheet portion 21.

[0108] The configurations in the above embodiments and each modified example may be combined as appropriate, as long as they do not contradict each other. [Explanation of symbols]

[0109] 1,1a,1b CNT heater 3. Covering part 21 Connecting sheet section 22 electrodes 23, 23a, 23b Additional conductive parts 33 Second through hole 211 First through hole 231 Third through hole C0 center C1 area L1 First virtual line L2 Second virtual line

Claims

1. It is a carbon nanotube heater, A pair of electrodes arranged side by side in the first direction, A connecting sheet portion is made of a sheet-like carbon nanotube molded body that extends in the first direction and a second direction perpendicular to the first direction, connecting the pair of electrodes, and generates heat when power is supplied to it, An additional conductive portion is laminated on the connecting sheet portion in a configuration region that includes the area of ​​the peripheral edge of the through hole provided in the connecting sheet portion that intersects with a first virtual straight line extending in the first direction through the center of the through hole, and which has a higher conductivity in the second direction than the connecting sheet portion. A sheet-like covering portion that covers the connecting sheet portion and the additional conductive portion from both sides in a third direction perpendicular to the first and second directions, A carbon nanotube heater equipped with this feature.

2. A carbon nanotube heater according to claim 1, The arrangement region of the additional conductive portion includes all of the region of the peripheral edge of the through hole that is located on both sides of the first virtual line with respect to the second direction and between a pair of second virtual lines parallel to the first virtual line, The pair of second virtual lines are located equidistant from the first virtual line with respect to the second direction. A carbon nanotube heater in which the distance between the pair of second virtual lines in the second direction is half the maximum length of the through hole in the second direction.

3. A carbon nanotube heater according to claim 2, The arrangement region of the additional conductive portion includes the entire periphery of the through hole in the carbon nanotube heater.

4. A carbon nanotube heater according to any one of claims 1 to 3, A carbon nanotube heater in which the orientation of the carbon nanotubes in the connecting sheet portion is parallel to the first direction.

5. A carbon nanotube heater according to any one of claims 1 to 3, The aforementioned additional conductive portion is a metal foil or metal plate, in a carbon nanotube heater.

6. A carbon nanotube heater according to any one of claims 1 to 3, The carbon nanotube heater is a carbon nanotube heater in which the additional conductive portion is a sheet-shaped carbon nanotube molded body in which the orientation of the carbon nanotubes is different from that of the connecting sheet portion.

7. A carbon nanotube heater according to claim 6, The orientation of the carbon nanotubes in the connecting sheet portion is parallel to the first direction. A carbon nanotube heater in which the orientation of the carbon nanotubes in the added conductive portion is in a direction inclined with respect to the first direction.

8. A carbon nanotube heater according to claim 7, A carbon nanotube heater in which the orientation of the carbon nanotubes in the added conductive portion is parallel to the second direction.

9. A carbon nanotube heater according to claim 6, The additional conductive portion is provided along the entire length of the connecting sheet portion in the second direction and has other through holes that overlap with the through holes, in a carbon nanotube heater.

10. A carbon nanotube heater according to any one of claims 1 to 3, The connecting sheet portion, the additional conductive portion, and the coating portion are flexible, forming a carbon nanotube heater.

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