JP7683335B2 - Insulation Device - Google Patents

Description

The present invention relates to a thermal insulation device in which components that operate at a specified temperature are covered with thermal insulation material.

Patent Document 1 describes a gas cogeneration system in which plate-shaped insulation is placed around a generator that includes a fuel cell, an evaporation section, a reforming section, and a combustion section, and these are supported by a housing.

JP 2018-206498 A

In order for a fuel cell system to generate electricity efficiently, it is important to manage the temperature of the internal components and other components or devices that make up the fuel cell system (hereinafter referred to as components, etc.). In addition, since the components that make up the fuel cell system are made of metal, they expand due to the heat generated during power generation, etc. For this reason, it is desirable to take thermal expansion into consideration when managing the temperature of the components, etc.

However, conventional fuel cell systems do not take into consideration the thermal expansion of parts, etc. As a result, for example, when parts, etc. thermally expand, gaps may appear between the parts, etc. and the insulation material, reducing the insulation performance and making it impossible to perform appropriate temperature control. In addition, when parts, etc. thermally expand, more insulation performance than necessary may be maintained, resulting in increased energy consumption for temperature control.

The present invention aims to provide an insulation device that can control the insulation performance of components that change temperature, such as components that make up a fuel cell system, according to their temperature.

One aspect of the present invention is an insulation device that includes a temperature-changing part and an insulating material covering the part, the insulating material including a first insulating material abutting a first surface of the part and a second insulating material abutting a second surface, which is a surface of the part adjacent to the first surface, and the first insulating material and the second insulating material abut at a corner of the part. In this insulation device, the insulating material includes a hinge portion formed by joining the first insulating material and the second insulating material, and an opening/closing portion that opens and closes with the hinge portion as a fulcrum so that the gap between the first insulating material and the second insulating material at the corner changes in response to the expansion or contraction of the part due to temperature change.

The present invention provides an insulation device that can control the insulation performance of parts whose temperatures change according to the temperature.

FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell system. FIG. 2 is a cross-sectional view showing the configuration of the heat insulating device. FIG. 3 is an enlarged cross-sectional view of a corner having an outward opening and closing portion in a thermal insulation material. FIG. 4 is a cross-sectional view showing the configuration of a thermal insulation device of a comparative example. FIG. 5 is an enlarged cross-sectional view of a corner having an inward opening in the thermal insulation material. FIG. 6 is a cross-sectional view showing the configuration of a corner portion of the first modified example. FIG. 7 is a cross-sectional view showing the configuration of a corner portion of the first modified example. FIG. 8 is a cross-sectional view showing the configuration of a corner portion of the second modified example. FIG. 9 is a cross-sectional view showing the configuration of a corner portion of the second modified example. FIG. 10 is an explanatory diagram showing the opening angle of the outward opening/closing part. FIG. 11 is a perspective view showing the configuration of the covering material. FIG. 12 is a perspective view showing another configuration of the covering material. FIG. 13 is a cross-sectional view showing the configuration of the third modified example. FIG. 14 is a graph showing the change over time in the temperature of the fuel cell stack and the flow rate of the cooling gas. FIG. 15 is a graph showing the temperature and fuel flow rate of the gas process unit over time. FIG. 16 is a graph showing the thermal conductivity of a thermal insulating material. FIG. 17 is a graph showing the change in temperature within the thermal insulation material.

The following describes an embodiment of the present invention with reference to the drawings.

Figure 1 is an explanatory diagram showing the schematic configuration of a fuel cell system 100. The fuel cell system 100 is installed, for example, under the floor of a vehicle as a power generation device to obtain electric power for use in the vehicle. As shown in Figure 1, the fuel cell system 100 includes, for example, a first fuel cell stack 10 (STK1), a second fuel cell stack 11 (STK2), a combustor 13 (CMB), and a heat exchanger 14 (HEX).

The first fuel cell stack 10 and the second fuel cell stack 11 are constructed by stacking multiple fuel cell cells, which are power generation sources. The individual fuel cell cells that make up the first fuel cell stack 10 and the second fuel cell stack 11 are, for example, solid oxide fuel cells (SOFCs).

The first fuel cell stack 10 is a so-called internal reforming type fuel cell stack, which reforms the raw fuel supplied from an injector 15 and uses it to generate power. The raw fuel is, for example, methane ( _CH4 ) or other hydrocarbons, or methanol or other alcohols.

The second fuel cell stack 11 is a fuel cell stack that generates power using fuel remaining in the exhaust gas of the first fuel cell stack 10. For this reason, the second fuel cell stack 11 is disposed downstream along the fuel flow path. Note that in this embodiment, the first fuel cell stack 10 and the second fuel cell stack 11 are separate for ease of explanation, but the first fuel cell stack 10 and the second fuel cell stack 11 may be integrated together to form a single fuel cell stack.

The oxidant used by the first fuel cell stack 10 and the second fuel cell stack 11 to generate electricity is, for example, oxygen contained in air. In this embodiment, the blower 16 supplies air as an oxidant gas (so-called cathode gas) to the first fuel cell stack 10 and the second fuel cell stack 11. More specifically, the oxidant gas, air, is supplied from the blower 16 to the second fuel cell stack 11, used in the power generation reaction in the second fuel cell stack 11, and then supplied to the first fuel cell stack 10, used in the power generation reaction in the first fuel cell stack 10, and discharged.

The combustor 13 mixes the exhaust gas of the fuel used for power generation in the first fuel cell stack 10 and the second fuel cell stack 11 (so-called anode off-gas) with the exhaust gas of the oxidant gas (so-called cathode off-gas) and performs catalytic combustion. The resulting combustion gas passes through the heat exchanger 14 and is discharged outside the fuel cell system 100.

The heat exchanger 14 uses the heat of the combustion gas to heat the air that the blower 16 supplies to the first fuel cell stack 10 and the second fuel cell stack 11.

In this embodiment, the combustor 13 and the heat exchanger 14 are integrally formed to form a gas process unit (GPU) 17.

The fuel cell system 100 has two paths through which the blower 16 supplies air to the second fuel cell stack 11: a first air supply path 18 and a second air supply path 19. The first air supply path 18 is a path that supplies heated air to the second fuel cell stack 11 via the heat exchanger 14. The second air supply path 19 is a path that supplies air to the second fuel cell stack 11 without passing through the heat exchanger 14 and without heating.

For example, when warming up the fuel cell system 100 to start it up, air is supplied to the first fuel cell stack 10 and the second fuel cell stack 11 through the first air supply path 18. On the other hand, after the fuel cell system 100 has started up, air is supplied through the first air supply path 18 and the second air supply path 19, or through the second air supply path 19. This is to maintain the temperature of the first fuel cell stack 10 and the second fuel cell stack 11 at a predetermined temperature determined according to the power generation efficiency, durability, etc. by cooling the first fuel cell stack 10 and/or the second fuel cell stack 11 as necessary.

In the fuel cell system 100 configured as described above, the components or devices that need to be controlled in temperature by suppressing heat transfer with the outside are, for example, the first fuel cell stack 10, the second fuel cell stack 11, the combustor 13, and the heat exchanger 14. For this reason, the first fuel cell stack 10, the second fuel cell stack 11, the combustor 13, and the heat exchanger 14 are covered with a heat insulating material 21 (see FIG. 2). Hereinafter, the components or devices to be insulated, such as the first fuel cell stack 10, the second fuel cell stack 11, the combustor 13, and the heat exchanger 14, are referred to as insulated components 20 (see FIG. 2). Note that covering the insulated components 20 with the heat insulating material 21 means that at least a part of the insulated components 20 is covered with the heat insulating material 21, and it is not necessary that the entire insulated components 20 are completely covered with the heat insulating material 21.

In addition, in this embodiment, among the various insulated parts 20 in the fuel cell system 100, the first fuel cell stack 10 and the second fuel cell stack 11 are each covered with a heat insulating material 21. Meanwhile, the combustor 13 and the heat exchanger 14 are integrated to form the gas process unit 17, so the combustor 13 and the heat exchanger 14, that is, the gas process unit 17 as a whole, are covered with the heat insulating material 21. Hereinafter, the insulated parts 20 covered with the heat insulating material 21 are referred to as the heat insulating device 110 (see FIG. 2). Therefore, in this embodiment, the first fuel cell stack 10 covered with the heat insulating material 21, the second fuel cell stack 11 covered with the heat insulating material 21, and the gas process unit 17 covered with the heat insulating material 21 are each the heat insulating device 110.

The first fuel cell stack 10 and the second fuel cell stack 11 may be entirely covered with the insulating material 21, or the combustor 13 and the heat exchanger 14 may each be covered with the insulating material 21. In addition, the insulated parts 20 may be entirely covered with the insulating material 21, or the entire fuel cell system 100 including the insulated parts 20 may be entirely covered with the insulating material 21.

Figure 2 is a cross-sectional view showing the configuration of the insulation device 110. As shown in Figure 2, the insulation device 110 includes a part to be insulated 20, a heat insulating material 21, and a case 22 that surrounds the outer periphery of these.

The insulated parts 20 are each formed in a roughly rectangular parallelepiped shape, and therefore have, for example, four corners in cross section. In this embodiment, the configuration of the insulating material 21 is described in detail for one of these corners, corner 25, but the other three corners are similar.

The temperature of the insulated parts 20 changes depending on the operating state of the fuel cell system 100 and/or the operating state of the insulated parts 20. For example, the temperature of the insulated parts 20 changes due to heat generation by the insulated parts 20, or due to heating or cooling from other insulated parts 20, etc. Since all of the insulated parts 20 contain many metal materials, when their temperature changes due to heat generation or cooling, etc., they expand or contract according to the amount of heat generation or cooling. The operating state of the fuel cell system 100 as a whole is determined, for example, by the amount of power generation required by the vehicle or the like in which it is mounted. The operating state of the insulated parts 20 is, for example, the amount of fuel and air supplied, the amount of heat generation, etc., and is controlled to achieve a predetermined amount of power generation.

The heat insulating material 21 is placed against the insulated part 20 and reduces heat transfer between the insulated part 20 and the outside world. In particular, the heat insulating material 21 of this embodiment does not always maintain a constant heat insulating performance, but changes its heat insulating performance depending on the operating state of the fuel cell system 100 and/or the insulated part 20. The change in heat insulating performance here does not mean that the heat insulating performance is simply switched between an insulated state and a state in which the insulation is broken, but that the heat insulating performance is controlled (fine-tuned) within a range that maintains the required heat insulating performance. To control the heat insulating performance, the heat insulating material 21 has opening and closing parts 26 at the corners 25 and each of the other corners.

The opening/closing section 26 is a section that opens and closes in response to the expansion or contraction of the insulated part 20. When the opening/closing section 26 is opened, the insulating performance of the insulating material 21 is increased. Conversely, when the opening/closing section 26 is closed, the insulating performance of the insulating material 21 is reduced within a range in which the required insulating performance is maintained. As will be described in detail later, the opening/closing section 26 has two specific forms: an outward opening/closing section 26a (see FIG. 3) formed with a slit that opens and closes on the outside, and an inward opening/closing section 26b (see FIG. 5) formed with a slit that opens and closes on the inside. The inside is the side where the insulated part 20 is located relative to the insulating material 21, and the outside is the side where the outside world of the case 22 and the insulating device 110 is located.

The case 22 is made of, for example, metal. Therefore, it can deform slightly in response to the expansion or contraction of the insulated part 20.

Figure 3 is an enlarged view of a corner 25 having an outward opening and closing portion 26a in the insulation material 21. Figure 3(A) shows the insulated part 20 in a contracted state, and Figure 3(B) shows the insulated part 20 in an expanded state. The dashed line in Figure 3(B) shows the outer shape of the insulated part 20 in a contracted state.

As shown in FIG. 3, the insulation material 21 is formed, for example, by stacking particulate insulation material 31 and fibrous insulation material 32 and covering them with a coating material 33.

The particulate insulation material 31 is formed by molding an inorganic compound containing, for example, fumed silica or fumed alumina with a particle size ranging from micron to nanometer size, and is porous. The particulate insulation material 31 is generally rigid, and even when pressed by the expansion of the insulated part 20, there is almost no change in its external shape. Even the particulate insulation material 31 is not a completely rigid body, and when there is a hinge portion 40 and an opening/closing portion 26 (here, the outward opening/closing portion 26a) as described below, it can bend to an extent that it can follow the change in external shape due to the expansion or contraction of the insulated part 20.

The fibrous insulation 32 is a cotton-like insulation material made of, for example, a ceramic material, and is flexible. More specifically, the fibrous insulation 32 is a heat-resistant insulation material formed into a fiber shape by bundling needle-shaped objects such as silica or alumina. When pressed by the expansion of the insulated part 20, the fibrous insulation 32 functions as an insulating buffer material to allow the particle insulation 31 to move in response to this.

The covering material 33 is a thin cloth-like insulating material that is flexible and heat-resistant. The covering material 33 covers the laminate of the particulate insulating material 31 and the fibrous insulating material 32, integrating them together. The covering material 33 is formed, for example, in a cylindrical (sleeve-like) shape, and after the particulate insulating material 31 and the fibrous insulating material 32 are inserted, the end portion that serves as the entrance is sewn or glued, etc., to accommodate the particulate insulating material 31 and the fibrous insulating material 32. The covering material 33 is formed, for example, by weaving silica fibers.

The insulating material 21 includes a first insulating material 35 that abuts against a first surface 34, which is one surface of the insulated part 20, at the corner 25, and a second insulating material 37 that abuts against a second surface 36, which is another surface of the insulated part 20 adjacent to the first surface 34. The first insulating material 35 and the second insulating material 37 abut against each other at the corner 25 of the insulated part 20.

In the insulating material 21 of this embodiment, the first insulating material 35 and the second insulating material 37 are partially joined at the corner portion 25 to form a hinge portion 40. This forms the opening and closing portion 26. In the opening and closing portion 26, the first insulating material 35 and the second insulating material 37 open and close with the hinge portion 40 as a fulcrum, changing the size (volume) of the gap between the first insulating material 35 and the second insulating material 37. More specifically, in FIG. 3, the first insulating material 35 and the second insulating material 37 are joined on the inside to form the hinge portion 40, so that the opening and closing portion 26 that is formed is an outward opening and closing portion 26a.

As shown in FIG. 3(A), this outward opening opening/closing section 26a is in an open state when the insulated part 20 is contracted, i.e., the gap between the first insulating material 35 and the second insulating material 37 is widened. On the other hand, as shown in FIG. 3(B), when the first insulating material 35 and the second insulating material 37 are pressed against the insulated part 20 from the inside due to thermal expansion of the insulated part 20, the outward opening/closing section 26a is in a closed state, i.e., the gap between the first insulating material 35 and the second insulating material 37 is narrowed (including a state where there is no gap). The smaller the gap between the first insulating material 35 and the second insulating material 37, the higher the insulating performance of the insulating material 21 at the corner 25.

In addition, when comparing the space S1 formed between the insulated part 20 and the insulating material 21 when the insulated part 20 is in a contracted state and the space S2 formed between the insulated part 20 and the insulating material 21 when the insulated part 20 is in an expanded state, the space S2 is smaller than the space S1. And the smaller the space formed between the insulated part 20 and the insulating material 21, the higher the insulating performance of the insulating material 21 at the corner 25.

Therefore, by opening and closing the outward opening opening section 26a with the hinge section 40 as a fulcrum, the insulating performance of the insulating material 21 at the corner section 25 changes when the insulated part 20 is in an expanded state and when it is in a contracted state. In other words, the insulating material 21 can automatically control its insulating performance by opening and closing the outward opening opening section 26a with the hinge section 40 as a fulcrum in response to the expansion and contraction of the insulated part 20.

Figure 4 is a cross-sectional view showing the configuration of an insulating device 111 of a comparative example. Figure 4(A) shows the insulated part 20 in a contracted state, and Figure 4(B) shows the insulated part 20 in an expanded state. The dashed line in Figure 4(B) shows the outer shape of the insulated part 20 in a contracted state.

4, the insulation device 111 of the comparative example has the insulated part 20 covered with a first insulating material 51 abutting the first surface 34 and a second insulating material 52 abutting the second surface 36, and housed in the case 22. That is, the basic structure of covering the insulated part 20 with insulating material to reduce heat transfer between the insulated part 20 and the outside world is similar to that of the insulation device 110 of this embodiment. However, in the insulation device 111 of the comparative example, the first insulating material 51 and the second insulating material 52 only abut at the abutment portion 53, and the first insulating material 51 and the second insulating material 52 are not joined at the corner portion 25, and a hinge portion 40 is not formed. Therefore, as shown in Figures 4(A) and 4(B), even if a gap 54 is formed outside the first insulating material 51 and the second insulating material 52, the size of the gap 54 does not change substantially even if the first insulating material 51 and the second insulating material 52 are pressed by the expansion of the insulated part 20. Therefore, the gap 54 in the insulating device 111 of the comparative example does not become the opening and closing part 26 in the insulating device 110 of this embodiment.

On the other hand, when comparing the space S3 formed between the insulated part 20 and the first and second insulating materials 51 and 52 when the insulated part 20 is in a contracted state with the similar space S4 when the insulated part 20 is in an expanded state, the space S4 is greatly expanded compared to the space S3. This is because the first insulating material 51 and the second insulating material 52 are separated from the first surface 34 and the second surface 36, respectively, due to the absence of the hinge portion 40 and the opening and closing portion 26 due to the expansion of the insulated part 20. In this way, when the first insulating material 51 and the second insulating material 52 are separated from the first surface 34 and the second surface 36, respectively, the insulating performance at the corner 25 is greatly reduced, and in some cases, the insulation is substantially broken. For this reason, in the insulating device 111 of the comparative example, the insulating performance at the corner 25 changes, but this change is extremely large and exceeds the range in which the necessary insulating performance can be maintained. In other words, it cannot be said that the insulating device 111 of the comparative example controls the insulating performance at the corner 25.

Therefore, as can be seen by comparing this embodiment with the comparative example, the insulation device 110 of this embodiment has the advantage that the insulation performance can be controlled according to the expansion and contraction of the insulated part 20 by providing the insulation material 21 with the hinge portion 40 and the opening and closing portion 26. In addition, since the adhesion of the insulation material 21 to the insulated part 20 is improved, the insulation is not broken while controlling the insulation performance, and the required insulation performance is easily maintained.

In particular, the outward opening opening/closing section 26a increases the insulating performance when the insulated part 20 is in an expanded state compared to when the insulated part 20 is in a contracted state. This means that the insulating performance changes in the opposite direction to the comparative example, where the insulating performance decreases due to the expansion of the insulated part 20. In other words, in the insulating device 110 of this embodiment, the insulating material 21 is provided with the hinge section 40 and in particular the outward opening/closing section 26a, making it possible to adjust the insulating performance in a direction that was not possible in the past, where the insulating performance is increased in response to the expansion of the insulated part 20.

Figure 5 is an enlarged view of a corner 25 having an inward opening opening/closing portion 26b in the insulating material 21. Figure 5(A) shows the insulated part 20 in a contracted state, and Figure 5(B) shows the insulated part 20 in an expanded state. The dashed line in Figure 5(B) shows the outer shape of the insulated part 20 in a contracted state. As described above, the inward opening opening/closing portion 26b is one form of the opening/closing portion 26. As shown in Figure 5, even when forming the inward opening opening/closing portion 26b, the internal structure of the insulating material 21 is the same as when forming the inward opening opening/closing portion 26b described above. However, when forming the inward opening opening/closing portion 26b, the first insulating material 35 and the second insulating material 37 are joined on the outside to form a hinge portion 40. As a result, the inward opening opening/closing portion 26b that opens and closes on the inside is formed.

When the insulated part 20 is contracted, as shown in FIG. 5(A), the inward opening opening section 26b is in a closed state, i.e., the gap between the first insulating material 35 and the second insulating material 37 is narrowed. On the other hand, as shown in FIG. 5(B), when the first insulating material 35 and the second insulating material 37 are pressed from the inside due to thermal expansion of the insulated part 20, the inward opening opening section 26b is in an open state, i.e., the gap between the first insulating material 35 and the second insulating material 37 is widened.

When the inward-opening opening/closing section 26b is formed, comparing the space S5 formed between the insulated part 20 and the insulating material 21 when the insulated part 20 is in a contracted state with the similar space S6 when the insulated part 20 is in an expanded state, the space S6 becomes smaller than the space S5, as in the case of forming the outward-opening opening/closing section 26a. However, when the inward-opening opening/closing section 26b is formed, the space S7 created by the inward-opening opening/closing section 26b opening is connected to this space S6. As a result, according to the inward-opening opening/closing section 26b, the improvement of the insulating performance when the insulated part 20 is in an expanded state is suppressed depending on the size of the space S6 and the space S7. Also, depending on the size of the space S6 and the space S7, the insulating performance when the insulated part 20 is in an expanded state is maintained or reduced.

Therefore, by opening and closing the inward opening opening section 26b with the hinge section 40 as a fulcrum, the insulating performance of the insulating material 21 at the corner section 25 changes when the insulated part is in an expanded state or in a contracted state. In other words, the insulating material 21 can automatically control its insulating performance by opening and closing the inward opening opening section 26b with the hinge section 40 as a fulcrum in response to the expansion and contraction of the insulated part 20.

The change in insulation performance when the inward-opening opening/closing section 26b is provided is controlled to be smaller than the change in insulation performance in the comparative example, and is within a range in which the required insulation performance can be maintained. Therefore, even when the opening/closing section 26 is the inward-opening opening/closing section 26b, the insulation device 110 of this embodiment has the effect of being able to control the insulation performance in response to the expansion and contraction of the insulated part 20, since the insulation material 21 is provided with the hinge section 40 and the opening/closing section 26.

[First Modification]
In the above embodiment, the insulating material 21 is formed of a laminate of the particulate insulating material 31 and the fibrous insulating material 32, so that the insulating material 21 conforms to the first surface 34 and the second surface 36, while preventing a gap from being generated between the case 22 and the insulating material 21. However, the configuration of the insulating material 21 is arbitrary. For example, the insulating material 21 can be formed of the particulate insulating material 31 without using the fibrous insulating material 32.

Figures 6 and 7 are cross-sectional views of a corner 25 showing the configuration of a first modified example. Figure 6 shows an example in which the insulating material 21 is made of particulate insulating material 31 and an outward opening opening section 26a is formed. Figure 7 shows an example in which the insulating material 21 is made of particulate insulating material 31 and an inward opening opening section 26b is formed. Figures 6(A) and 7(A) show the insulated part 20 in a contracted state, and Figures 6(B) and 7(B) show the insulated part 20 in an expanded state. The dashed lines in Figures 6(B) and 7(B) show the outer shape of the insulated part 20 in a contracted state.

As shown in FIG. 6(A), in the first modified example, the hinge portion 40 and the outward opening opening portion 26a can be formed in the same manner as in the above embodiment. However, as shown in FIG. 6(B), when the insulated part 20 expands, the case 22 is deformed. The case 22 can change shape to such an extent that it follows the change in external shape caused by the thermal expansion of the insulated part 20, and can return to its original shape when the insulated part 20 contracts. Therefore, as shown in FIG. 6, even when the insulation material 21 is made of a generally rigid particle insulation material 31, the hinge portion 40 and the outward opening opening portion 26a can be provided to control the insulation performance. The same applies when the insulation material 21 is made of particle insulation material 31 and an inward opening opening portion 26b is formed, as shown in FIG. 7(A) and FIG. 7(B).

[Second Modification]
In the above embodiment, the opening/closing portion 26 (the outward-opening opening/closing portion 26a and the inward-opening opening/closing portion 26b) are formed approximately parallel to the second surface 36 of the insulated part 20, but as long as the opening/closing portion 26 is provided approximately at the corner portion 25, its position, orientation, etc. can be adjusted.

Figures 8 and 9 are cross-sectional views of the corner portion 25 showing the configuration of the second modified example. Figure 8 shows an example in which the outward opening opening/closing portion 26a is formed at an angle to the first surface 34 and the second surface 36. Figure 9 shows an example in which the inward opening opening/closing portion 26b is formed at an angle to the first surface 34 and the second surface 36. Figures 8(A) and 9(A) show the insulated part 20 in a contracted state, and Figures 8(B) and 9(B) show the insulated part 20 in an expanded state. The dashed lines in Figures 8(B) and 9(B) show the outer shape of the insulated part 20 in a contracted state.

As shown in Figures 8(A) and 8(B), the outward opening opening/closing portion 26a may be formed at an angle to the first surface 34 and the second surface 36. In this case as well, when the insulated part 20 expands, the outward opening opening/closing portion 26a closes, narrowing the gap between the first insulating material 35 and the second insulating material 37, thereby improving the insulating performance at the corner 25.

Also, as shown in Figures 9(A) and 9(B), the inward opening opening/closing portion 26b may also be formed at an angle to the first surface 34 and the second surface 36. In this case, too, when the insulated part 20 expands, the inward opening opening/closing portion 26b opens, and the gap between the first insulating material 35 and the second insulating material 37 widens, thereby suppressing an increase in the insulating performance at the corner portion 25. Also, depending on the size of the space between the first insulating material 35 and the second insulating material 37, the insulating performance when the insulated part 20 is in an expanded state is maintained or reduced.

The reason why opening and closing sections 26 are provided at corners 25 and other corners is that there is a particularly high need to control the insulation performance compared to flat areas where the insulation material 21 is in close contact. At the same time, providing opening and closing sections 26 at corners 25 also has the advantage of making it easier to control the insulation performance.

[Opening angle of outward opening opening part]
Fig. 10 is an explanatory diagram showing the opening angle of the outward opening opening/closing part 26a. Fig. 10(A) shows the insulated part 20 in a contracted state, and Fig. 10(B) shows the insulated part 20 in an expanded state. The dashed line in Fig. 10(B) shows the outer shape of the insulated part 20 in a contracted state.

As shown in FIG. 10(A), when forming an outward opening opening/closing section 26a, the opening angle of the outward opening opening/closing section 26a is α when the insulated part 20 is in a contracted state. On the other hand, as shown in FIG. 10(B), when the insulated part 20 is in an expanded state, the displacement angle of the first surface 34 based on the corner 25 is β1, and the displacement angle of the second surface 36 based on the corner 25 is β2. In this case, the opening angle α of the outward opening/closing section 26a is formed so as to be equal to the sum of the displacement angle β1 of the first surface 34 and the displacement angle β2 of the second surface 36 based on the corner 25. In other words, α = β1 + β2.

When the opening angle α is greater than the sum of the displacement angle β1 of the first surface 34 and the displacement angle β2 of the second surface 36, i.e., α>β1+β2, the outward opening opening/closing portion 26a does not close even after the insulated part 20 expands, and a gap remains between the first insulating material 35 and the second insulating material 37. Then, after the insulated part 20 expands, the insulating performance at the corner 25 may be insufficient.

On the other hand, if the opening angle α is smaller than the sum of the displacement angle β1 of the first surface 34 and the displacement angle β2 of the second surface 36, and the relationship is α<β1+β2, the opening angle α is insufficient for the amount of expansion of the insulated part 20. As a result, when the insulated part 20 expands, the first insulating material 35 and the second insulating material 37 come into strong contact with each other, which can cause excess load on the first insulating material 35 and the second insulating material 37, resulting in defects such as cracks.

Therefore, when forming the outward opening opening/closing portion 26a, it is preferable to form the opening angle α so that it is equal to the sum of the displacement angle β1 of the first surface 34 and the displacement angle β2 of the second surface 36, with the corner 25 as the reference. However, in order to adjust (reduce) the insulation performance at the corner 25 after the insulated part 20 expands, the opening angle α may be intentionally made larger than the sum of the displacement angle β1 of the first surface 34 and the displacement angle β2 of the second surface 36.

When the opening/closing section 26 is an inward-opening opening/closing section 26b, the condition regarding the opening angle α (α = β1 + β2) is automatically met.

[Configuration of coating material]
Fig. 11 is a perspective view showing the configuration of the covering material 33. As shown in Fig. 11, the covering material 33 is woven, for example, into a single tube or bag shape. In Fig. 11, the covering material 33 is made up of a first tubular portion 61 constituting the first insulating material 35 and a second tubular portion 62 constituting the second insulating material 37. The first tubular portion 61 and the second tubular portion 62 are not joined by sewing or the like, but are woven integrally.

An opening 61a is formed at one end of the first tube 61 on the negative side in the X direction, and the particle insulation 31 and fiber insulation 32 that will become the first insulation 35 are inserted through this opening 61a. After the particle insulation 31 and fiber insulation 32 are inserted, the lid 61b of the first tube 61 is closed and sewn, glued, or the like, and sealed. Similarly, an opening 62a is formed at one end of the second tube 62 on the negative side in the Y direction, and the particle insulation 31 and fiber insulation 32 that will become the second insulation 37 are inserted through this opening 62a. The lid 62b of the second tube 62 is closed and sewn, glued, or the like, and sealed.

In this example, the covering material 33 has openings 61a, 62a and lids 61b, 62b. However, since the covering material 33 is flexible, slits may be formed instead to serve as insertion openings for the particle insulation material 31 and the fiber insulation material 32.

As described above, when the first tubular portion 61 and the second tubular portion 62 are formed by integrally weaving, the surface 63 where the first tubular portion 61 abuts against the first surface 34 and the surface 64 where the second tubular portion 62 abuts against the second surface 36 are formed from a single continuous covering material 33. Therefore, the covering material 33 that covers the first insulating material 35 and the second insulating material 37 is not joined by sewing or the like, but is formed from a single continuous covering material 33 at least at the hinge portion 40. As a result, the hinge portion 40 is formed from the covering material 33.

In this way, by forming at least the hinge portion 40 from one continuous covering material 33, there is no stitching at the hinge portion 40, which is the movable portion of the insulation material 21, and the strength of the hinge portion 40 is high compared to when it is joined later by sewing or the like. In addition, the mesh size of the covering material 33 is small. As a result, there is an advantage that powder leakage from the hinge portion 40 is unlikely to occur even if the particle insulation material 31 is worn down by repeatedly opening and closing the opening and closing portion 26 (outward opening and closing portion 26a in FIG. 11).

Figure 12 is a perspective view showing another configuration of the covering material 33. As described above, it is particularly preferable that the hinge portion 40 is formed by a single piece of covering material 33 rather than by sewing. However, as shown in Figure 12, the first tubular portion 61 and the second tubular portion 62 may be made separately, and the hinge portion 40 may be formed by sewing. In this case, it is also possible to control the heat insulating performance at the corner portion 25.

In addition, while Figures 11 and 12 show an example in which an outward opening/closing section 26a is formed as the opening/closing section 26, the same applies when an inward opening/closing section 26b is formed.

[Third Modification]
13 is a cross-sectional view showing the configuration of the third modified example. In the third modified example, the outward opening/closing section 26a is filled with fiber insulation material 32. The rest of the configuration is the same as the above embodiment.

The fibrous insulation material 32 is flexible and, due to its structure, can exert elasticity. Therefore, if the fibrous insulation material 32 is filled into the outward opening opening section 26a and is sandwiched between the first insulation material 35 and the second insulation material 37, when the insulated part 20 contracts, the reaction force from the sandwiched fibrous insulation material 32 makes it easier for the first insulation material 35 and the second insulation material 37 to return to their original positions.

Although not shown, when the opening/closing section 26 is an inward-opening opening/closing section 26b, it is preferable to fill the inward-opening opening/closing section 26b with fiber insulation material 32 as described above and sandwich it between the first insulation material 35 and the second insulation material 37. In this way, when the inward-opening opening/closing section 26b is filled with fiber insulation material 32, the reaction force of the sandwiched fiber insulation material 32 makes it easier for the insulated part 20 to move in response to the expansion of the insulated part 20.

[Selection between outward opening and inward opening]
The opening/closing portion 26 provided at the corner portion 25 can be selected from an outward opening/closing portion 26a and an inward opening/closing portion 26b. However, it is preferable to determine whether the outward opening/closing portion 26a or the inward opening/closing portion 26b is to be provided at the corner portion 25 depending on the properties of the specific insulated part 20 to be insulated, as described below.

Figure 14 is a graph showing the change over time in the temperature of the fuel cell stack (first fuel cell stack 10 or second fuel cell stack 11) and the flow rate of the cooling gas. Figure 14 (A) shows the change over time in the stack temperature when the outward opening opening/closing section 26a is used, and Figure 14 (B) shows the change over time in the flow rate of the cooling gas when the outward opening opening/closing section 26a is used. Figure 14 (C) shows the change over time in the stack temperature when the inward opening opening/closing section 26b is used, and Figure 14 (D) shows the change over time in the stack temperature when the inward opening opening/closing section 26b is used. The cooling gas is unheated air (oxidizer) supplied from the blower 16 via the second air supply path 19.

As shown in Figures 14(A) and 14(B), the fuel cell stack expands due to thermal expansion, and the stack temperature rises at time t1 when the outward opening opening/closing section 26a is closed. In this case, the outward opening opening/closing section 26a has high insulation performance. The fuel cell stack needs to be operated at a predetermined high temperature (here, temperature T1) to generate electricity efficiently, but at the same time, the temperature needs to be managed so as not to overheat, taking into account heat resistance, etc. For this reason, the fuel cell system 100 increases the flow rate of the cooling gas from G1 to G2 using a control device (not shown). As a result, the stack temperature temporarily rises to temperature Ta, but is returned to the temperature T1 to be maintained at time t2.

On the other hand, as shown in FIG. 14(C) and FIG. 14(D), when the inward opening opening/closing section 26b is used, the fuel cell stack expands due to thermal expansion, and the stack temperature rises at time t1 when the inward opening opening/closing section 26b is open. In this case, the inward opening opening/closing section 26b is in a state where the increase in the insulation performance is suppressed, so the increase in the stack temperature is suppressed more than when the outward opening opening/closing section 26a is used. For example, the temperature Tb that the stack temperature reaches when the inward opening opening/closing section 26b is used is lower than the temperature Ta that the stack temperature reaches when the outward opening opening/closing section 26a is used. Therefore, although the fuel cell system 100 increases the flow rate of the cooling gas from G1 in response to the increase in the stack temperature, the flow rate of the cooling gas is a flow rate G3 that is lower than when the outward opening opening/closing section 26a is used. This has the advantage of reducing the power consumption of the auxiliary blower 16.

Therefore, when the insulated part 20 is a fuel cell stack, it is preferable that the opening/closing part 26 adopts an inward opening/closing part 26b. In addition, since the first fuel cell stack 10 of the present embodiment is an internal reforming type, the fuel cell system 100 does not have a reformer independent of the fuel cell stack, but if an independent reformer is included, this reformer is also an insulated part 20. In an insulating device in which the reformer is the insulated part 20, it is preferable to adopt an inward opening/closing part 26b for the fuel cell stack as insulated part 20 as described above. However, if the reformer performs partial oxidation reforming (POX), an outward opening/closing part 26a may be adopted.

Figure 15 is a graph showing the change over time in the temperature of the gas process unit 17 (GPU) and the fuel flow rate. Figure 15(A) shows the change over time in the temperature of the gas process unit 17 when the outward opening/closing section 26a is used, and Figure 15(B) shows the change over time in the fuel flow rate when the outward opening/closing section 26a is used. Figure 15(C) shows the change over time in the temperature of the gas process unit 17 when the inward opening/closing section 26b is used, and Figure 15(D) shows the change over time in the fuel flow rate when the inward opening/closing section 26b is used.

The gas process unit 17 is mainly used for warming up the fuel cell system 100 when it is started up. For this reason, it is preferable for the gas process unit 17 to reach the predetermined temperature (here, temperature T2) quickly with as little fuel as possible. Therefore, for comparison, as shown in Figures 15(A) and 15(C), it is assumed here that the temperature of the gas process unit 17 reaches the predetermined temperature T2 at time t3 after the fuel cell system 100 is started up, regardless of whether the outward opening/closing section 26a or the inward opening/closing section 26b is used.

At this time, as shown in FIG. 15(B), if the outward opening opening/closing section 26a is used, the temperature of the gas process unit 17 rises, causing the outward opening/closing section 26a to close, improving the insulation performance. As a result, the temperature of the gas process unit 17 reaches T2 at time t3, and the fuel flow rate required to maintain this temperature is F2.

On the other hand, as shown in FIG. 15(C), when the inward opening opening/closing section 26b is used, even if the temperature of the gas process unit 17 rises, the inward opening opening/closing section 26b opens, suppressing an increase in the insulation performance. As a result, the fuel flow rate required to make the temperature of the gas process unit 17 reach T2 at time t3 and maintain that temperature is a flow rate F1 that is greater than the flow rate F2 when the outward opening/closing section 26a is used. Therefore, by using the inward opening/closing section 26b, it is possible to reduce fuel consumption for warming up. Also, if a certain amount of fuel is consumed for warming up, the use of the inward opening/closing section 26b allows warming up to be completed earlier.

Therefore, when the insulated part 20 is the gas process unit 17, it is preferable to adopt an outward opening opening/closing part 26a for the opening/closing part 26. In addition, in this embodiment, the combustor 13 and the heat exchanger 14 are integrated to form the gas process unit 17, but when the combustor 13 and the heat exchanger 14 are separate, the combustor 13 and the heat exchanger 14 are each the insulated part 20. And, in an insulation device in which the combustor 13 or the heat exchanger 14 is the insulated part 20, it is preferable to adopt an outward opening opening/closing part 26a, as in the case where the gas process unit 17 is the insulated part 20 as described above.

[Layer sequence of particle insulation and fiber insulation]
In the above-described embodiment and modified examples, when the particulate insulation material 31 and the fibrous insulation material 32 are laminated to form the insulation material 21, the inside where the insulated part 20 is located is the particulate insulation material 31, and the outside where the case 22 and the outside world are located is the fibrous insulation material 32. This is for the following reasons.

Figure 16 is a graph showing the thermal conductivity of insulation materials. As shown in Figure 16, the thermal conductivity of particle insulation material 31 is generally lower than that of air, and has high insulation performance. On the other hand, the thermal conductivity of fibrous insulation material 32 is generally higher than that of air, and has relatively low insulation performance.

Figure 17 is a graph showing the change in temperature within the insulation 21. Figure 17(A) shows a case where, contrary to the above embodiment, the particulate insulation 31 is placed on the outside where the relatively low temperature case 22 is located, and the fibrous insulation 32 is placed on the inside where the relatively high temperature insulated part 20 is located. Meanwhile, Figure 17(B) shows a case where, similar to the above embodiment, the fibrous insulation 32 is placed on the outside where the low temperature case 22 is located, and the particulate insulation 31 is placed on the inside where the high temperature insulated part 20 is located. Here, the temperature of the insulated part 20 is T4, and the temperature of the case 22 is T5.

When comparing the thickness _δA of the insulation 21 when the particulate insulation 31 is placed on the high temperature side with the thickness δB of the insulation 21 when the fibrous insulation 32 is placed on the high temperature side, _δA > _δB because of the thermal conductivity relationship shown in Figure 16. Therefore, when the particulate insulation 31 is placed on the inside where the high temperature insulated part 20 is located, the insulation 21 can be made thinner than if the layering order _were reversed. As a result, the insulation device 110 can be made small, thin, and lightweight.

As described above, the heat insulation device 110 according to the present embodiment includes the insulated part 20, which is a part whose temperature changes, and the heat insulation material 21 that covers the insulated part 20. The heat insulation material 21 also includes the first heat insulation material 35 that abuts against the first surface 34 of the insulated part 20, and the second heat insulation material 37 that abuts against the second surface 36, which is the surface of the insulated part 20 adjacent to the first surface 34. The first heat insulation material 35 and the second heat insulation material 37 abut at the corner 25 of the insulated part 20. In addition, the heat insulation material 21 includes a hinge portion 40 formed by joining the first heat insulation material 35 and the second heat insulation material 37, and an opening/closing portion 26 that opens and closes with the hinge portion 40 as a fulcrum so that the gap between the first heat insulation material 35 and the second heat insulation material 37 at the corner 25 changes depending on the expansion or contraction of the insulated part 20 due to temperature changes.

As described above, at the corner 25, the insulating material 21 is provided with the hinge portion 40 and the opening/closing portion 26, so that as the insulated part 20 expands or contracts, the opening/closing portion 26 opens and closes while the insulating material 21 maintains close contact with the insulated part 20, changing the insulating performance at the corner 25. As a result, the insulating device 110 according to this embodiment can control the insulating performance of the insulated part 20 according to its temperature.

The opening/closing section 26 can be configured to close when the insulated part 20 expands and open when the insulated part 20 contracts (outward opening opening/closing section 26a). Specifically, when the side of the insulated part 20 is the inside and the side opposite the inside is the outside, the hinge section 40 is formed by connecting the first insulating material 35 and the second insulating material 37 on the outside, and the opening/closing section 26 (outward opening opening/closing section 26a) is formed so that the outside of the first insulating material 35 and the second insulating material 37 opens and closes.

In this way, by making the opening/closing section 26 an outward opening opening/closing section 26a, the insulating performance can be controlled so that when the insulated part 20 expands due to temperature changes, the insulating performance is increased, and when the insulated part 20 contracts, the insulating performance is relatively decreased.

On the other hand, the opening/closing section 26 can be structured to open when the insulated part 20 expands and close when the insulated part 20 contracts (inward opening opening/closing section 26b). Specifically, when the side of the insulated part 20 is the inside and the side opposite the inside is the outside, the hinge section 40 is formed by connecting the first insulating material 35 and the second insulating material 37 on the outside, and the opening/closing section 26 is formed so that the inside of the first insulating material 35 and the second insulating material 37 opens and closes.

In this way, by making the opening/closing section 26 an inward-opening opening/closing section 26b, it is possible to improve the insulation performance when the insulated part 20 contracts due to temperature changes, and to suppress an increase in insulation performance when the insulated part 20 expands.

Furthermore, with respect to the corner 25, the opening angle α of the opening/closing portion 26 is equal to the sum of the displacement angle β1 of the first surface 34 and the displacement angle β2 of the second surface 36. In this case, it is possible to prevent insufficient insulation and internal damage to the insulation material 21.

The insulating material 21 is formed by covering it with a covering material 33. The covering material 33 that covers the first insulating material 35 and the second insulating material 37 is formed of a single continuous covering material 33 at least at the hinge portion 40, so that the hinge portion 40 is formed of the covering material 33. By forming the hinge portion 40 from a single continuous covering material 33 in this way, the strength of the hinge portion 40 is improved and powder leakage of the first insulating material 35 and the like can be prevented.

It is also preferable that a flexible insulating material, such as fibrous insulating material 32, is sandwiched between the opening and closing portion 26. In this case, the elastic force of this flexible insulating material assists in opening and closing the opening and closing portion 26, making it easier for the opening and closing portion 26 to move smoothly. The flexible insulating material is, for example, a fibrous insulating material, i.e., fibrous insulating material 32.

When the opening/closing section 26 is an outward opening opening/closing section 26a, it is preferable that the insulated part 20 is, for example, the combustor 13 and/or the heat exchanger 14 that constitute the fuel cell system 100. In this case, the warm-up of the fuel cell system 100 can be completed with a small amount of fuel.

When the opening/closing portion 26 is an inward opening opening/closing portion 26b, it is preferable that the insulated part 20 is, for example, a fuel cell stack (first fuel cell stack 10 and/or second fuel cell stack 11). In this case, the power consumption of the auxiliary equipment (blower 16) can be reduced while maintaining the temperature of the fuel cell stack at a high temperature that provides good power generation efficiency and preventing overheating.

It is preferable that the insulating material 21 contains at least a first insulating material (particle insulating material 31) that has a thermal conductivity lower than that of air. This allows the insulating performance of the insulating material 21 to be basically high while still allowing the insulating performance to be controlled.

When the insulation material 21 is formed by layering the first insulation material 35 and the second insulation material (fibrous insulation material 32) that has a higher thermal conductivity than air, the first insulation material (particle insulation material 31) is placed on the side of the high-temperature insulated part 20. This allows the insulation material 21 to be formed thin. As a result, the insulation device 110 is made smaller, thinner, and lighter.

Although the embodiments of the present invention have been described above, the configurations described in the above embodiments and modifications are merely examples of application of the present invention, and are not intended to limit the technical scope of the present invention. For example, in the above embodiments and modifications, the insulation device 110 insulates the insulated part 20 that is part of the fuel cell system 100, but the insulation device 110 is also suitable for other devices or systems that include parts to be insulated. In addition, the above embodiments and modifications can be implemented in any combination of part or all. For example, a mixture of the outward opening opening/closing part 26a and the inward opening opening/closing part 26b may be used in one insulation device 110. In addition, when the entire fuel cell system 100 is insulated, that is, when the entire fuel cell system 100 is the insulated part 20, either the outward opening opening/closing part 26a or the inward opening opening/closing part 26b can be used as the opening/closing part 26. For example, the inward opening opening/closing part 26b can be used by giving priority to warming up the fuel cell system 100.

20: Insulated part, 21: Insulation material, 22: Case, 25: Corner, 26: Opening/closing part, 26a: Outward opening/closing part, 26b: Inward opening/closing part, 31: Particle insulation material, 32: Fiber insulation material, 33: Covering material, 34: First surface, 35: First insulation material, 36: Second surface, 37: Second insulation material, 40: Hinge part, 100: Fuel cell system, 110: Insulation device

Claims (13)

An insulation device comprising: a component whose temperature changes; and an insulating material covering the component, the insulating material including a first insulating material in contact with a first surface of the component and a second insulating material in contact with a second surface, which is a surface of the component adjacent to the first surface; and the first insulating material and the second insulating material in contact with each other at a corner of the component,
The thermal insulation material is
a hinge portion formed by coupling the first insulating material and the second insulating material;
an opening/closing unit that opens and closes with the hinge unit as a fulcrum so that a gap between the first insulating material and the second insulating material at the corner portion changes in response to expansion or contraction of the part due to a temperature change;
Equipped with
Insulation device. 2. The thermal insulation device according to claim 1,
The opening and closing portion closes when the part expands and opens when the part contracts.
Insulation device. The thermal insulation device according to claim 1 or 2,
When the side of the part is defined as the inside and the side opposite to the inside is defined as the outside,
The hinge portion is formed by connecting the first insulating material and the second insulating material on the inside,
The opening and closing portion is formed so that the outer sides of the first insulating material and the second insulating material are opened and closed.
Insulation device. 2. The thermal insulation device according to claim 1,
The opening and closing portion opens when the part expands and closes when the part contracts.
Insulation device. 5. The thermal insulation device according to claim 1 or 4,
When the side of the part is defined as the inside and the side opposite to the inside is defined as the outside,
The hinge portion is formed by connecting the first insulating material and the second insulating material at the outer side,
The opening and closing portion is formed so that the inside of the first insulating material and the inside of the second insulating material are opened and closed.
Insulation device. The heat insulating device according to any one of claims 1 to 5,
With respect to the corner portion, an opening angle of the opening/closing portion is equal to the sum of a displacement angle of the first surface and a displacement angle of the second surface.
Insulation device. The heat insulating device according to any one of claims 1 to 6,
The heat insulating material is formed by covering it with a covering material,
The covering material covering the first insulating material and the second insulating material is formed of one continuous covering material at least at the hinge portion, so that the hinge portion is formed of the covering material.
Insulation device. The heat insulating device according to any one of claims 1 to 7,
A flexible insulating material is sandwiched between the opening and closing parts.
Insulation device. 9. The thermal insulation device according to claim 8,
The flexible insulation is a fibrous insulation.
Insulation device. The thermal insulation device according to claim 2 or 3,
The component is a combustor and/or a heat exchanger that constitutes a fuel cell system.
Insulation device. 6. The thermal insulation device according to claim 4 or 5,
The component is a fuel cell stack.
Insulation device. The thermal insulation device according to any one of claims 1 to 11,
The thermal insulation material includes at least a first thermal insulation material having a thermal conductivity lower than that of air,
Insulation device. 13. The insulation device of claim 12,
The heat insulating material is formed by laminating the first heat insulating material and a second heat insulating material having a higher thermal conductivity than air,
The first insulating material is disposed on the side of the component.
Insulation device.

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