JP5402346B2 - Heat dissipation device - Google Patents

Description

  The present invention relates to a heat dissipation device.

  In order to radiate the heat of the ceramic substrate, a heat transfer structure in which a heat transfer sheet is inserted between the ceramic substrate and the heat radiating plate is known.

Japanese Patent Laid-Open No. 3-97571

  By the way, in the fuel cell, a pump for compressing the reaction gas is used. Since the efficiency of the pump decreases at a high temperature, it is preferable to provide a heat sink for heat dissipation. On the other hand, in a mobile vehicle using a fuel cell as power or a fuel cell installed in a cold region, the fuel cell may be started at a low temperature below freezing point where the pump freezes. In such a case, it is preferable to quickly raise the temperature of the pump to eliminate freezing of the pump. Here, when the heat sink is connected to the pump via a heat transfer sheet as in the prior art, it is difficult to quickly raise the temperature of the pump because heat is taken away by the heat sink even at low temperatures. It becomes. Therefore, it is difficult to quickly eliminate the freezing of the pump. This is not limited to the case where the heating element is a pump, and the same applies to various heating elements.

  The present invention solves at least a part of the above-mentioned problems, and when the heating element is at a low temperature, the heat transfer to the heat radiating plate is suppressed to quickly increase the temperature of the heating element, and the heating element is at a high temperature. In this case, an object of the present invention is to provide a heat dissipation device capable of promoting heat transfer to the heat dissipation plate to dissipate heat.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.
According to one form of this invention, the thermal radiation apparatus for radiating the heat | fever of a heat generating body is provided. The heat dissipating device is disposed between a heat dissipating plate, a support member that supports the heat dissipating plate apart from the heat generating member, and between the heat dissipating plate and the heat generating member, and the temperature of the heat generating member is predetermined. When it is lower than the temperature, it is separated from at least one of the heat radiating plate and the heating element, and when the temperature of the heating element is higher than a predetermined temperature, it is in contact with both the heat radiating plate and the heating element. A heat transfer member, and a moving member that is provided as a separate member from the heat transfer member and moves the heat transfer member, wherein the moving member is a bimetal, a bidirectional shape memory alloy, and an actuator. The heat sink has a bottom surface that is inclined with respect to the surface of the heating element, and the heat transfer member has a surface that can be in contact with the bottom surface of the heat sink, and the moving member. Is the temperature of the heating element Is higher than a predetermined temperature, the heat transfer member is brought into contact with both the radiator plate and the heating element, and when the temperature of the heating element is lower than the predetermined temperature, A heat transfer member is separated from at least one of the heat radiating plate and the heating element, and the linear expansion coefficient of the heat transfer member is larger than the linear expansion coefficient of the support member. According to the heat dissipation device of this aspect, when the temperature of the heating element rises, the moving member moves the heat transfer member to contact the heat radiating plate. At this time, the heat dissipation plate has a bottom surface that is inclined with respect to the surface of the heating element, and the heat transfer member has a surface that can be in contact with the bottom surface of the heat dissipation plate. It becomes possible.

[Application Example 1]
A heat dissipating device for dissipating the heat of the heat generating element, the heat dissipating plate, a support member that supports the heat dissipating plate spaced apart from the heat generating member, and disposed between the heat dissipating plate and the heat generating member, When the temperature of the heating element is lower than a predetermined temperature, it is separated from at least one of the heat radiating plate and the heating element, and when the temperature of the heating element is higher than a predetermined temperature, the A heat dissipating device comprising: a heat dissipating plate and a heat transfer member in contact with both of the heating elements.
According to this application example, when the heating element is at a low temperature, heat transfer to the heat sink is suppressed and the temperature of the heating element is quickly increased, and when the heating element is high, the heat transfer to the heat sink is performed. Heat can be promoted and released.

[Application Example 2]
The heat radiating device according to Application Example 1, wherein a linear expansion coefficient of the heat transfer member is larger than a linear expansion coefficient of the support member.
According to this application example, it is possible to promote heat dissipation by using the thermal expansion of the heat transfer member to bring the heat transfer member into contact with both the heating element and the heat radiating plate at a high temperature.

[Application Example 3]
The heat radiating device according to Application Example 1 or Application Example 2, wherein the heat transfer member is in contact with the heating element.
According to this application example, the heat of the heating element can be used for expansion of the heat transfer member.

[Application Example 4]
The heat radiating device according to any one of application examples 1 to 3, wherein the heat radiating device is disposed vertically above the heating element.
According to this application example, the heat transfer member of the heat dissipation device can be brought into contact with the heating element by gravity.

[Application Example 5]
In the heat radiating device according to any one of Application Example 1 to Application Example 4, the support member is connected to the heat radiating plate and the heating element, and the heat conductivity of the support member is the heat conduction of the heat transfer member. Heat dissipation device smaller than the rate.
According to this application example, heat can be suppressed from being conducted to the heat sink via the support member.

[Application Example 6]
The heat dissipating device according to Application Example 1 further includes a bimetal that deforms depending on the temperature of the heating element, and the bimetal is configured to dispose the heat transfer member when the temperature of the heating element is lower than a predetermined temperature. The heat transfer plate is separated from at least one of the heat radiating plate and the heat generating element, and the heat transfer member is brought into contact with both the heat radiating plate and the heat generating element when the temperature of the heat generating element is higher than a predetermined temperature. , Heat dissipation device.
According to this application example, the heat transfer member is brought into contact with both the heat radiating plate and the heating element, or the heat transfer member is separated from at least one of the heat radiating plate and the heat generating element, using a bimetal warp. Is possible.

[Application Example 7]
In the heat dissipation device according to Application Example 1, the heat dissipation device further includes an elastic member made of a bidirectional shape memory alloy that deforms between two shapes depending on the temperature of the heating element, and the elastic member When the body temperature is lower than a predetermined temperature, the heat transfer member is separated from at least one of the heat radiating plate and the heat generating body, and the temperature of the heat generating body is higher than a predetermined temperature. In this case, the heat radiating device brings the heat transfer member into contact with both the heat radiating plate and the heating element.
According to this application example, since the elastic member is a bidirectional shape memory alloy, it has two forms depending on the temperature. And it becomes possible to make a heat-transfer member contact both a heat sink and a heat generating body using the two forms, or to separate a heat transfer member from at least one of a heat sink and a heat generating body. .

[Application Example 8]
The heat dissipation device according to any one of Application Example 1 to Application Example 7, wherein the heat dissipation device compresses a reaction gas using a pump and supplies the reaction gas to a fuel cell stack having an end plate. A heat dissipation device used in a system, wherein the heating element is the pump, and the heat dissipation plate is the end plate.
According to this application example, in the fuel cell system, the temperature of the pump can be optimized, and the end plate can be used as a heat radiating plate, so that the number of parts can be reduced.

  In addition, this invention can be implement | achieved with various forms, for example, can be implement | achieved with various forms, such as a thermal radiation structure, a thermal radiation method other than a thermal radiation apparatus.

It is explanatory drawing which shows a 1st Example. It is explanatory drawing when the heat radiating device is seen from vertically below and above. It is explanatory drawing which shows a 2nd Example. It is explanatory drawing which shows a 3rd Example. It is explanatory drawing which shows the modification of a 3rd Example. It is explanatory drawing which shows a 4th Example. It is explanatory drawing which shows the modification of a 4th Example. It is explanatory drawing which shows a modification. It is explanatory drawing which shows another modification. It is explanatory drawing when the direction of a heat sink is changed.

  FIG. 1 is an explanatory diagram showing the first embodiment. The heat dissipation device 100 includes a heat dissipation plate 110, a support member 120, and a heat transfer member 130. The heat sink 110 includes fins 111 for promoting heat dissipation. However, the fin 111 can be omitted. As a material of the heat sink 110, for example, aluminum, copper, or an alloy thereof can be used. The support member 120 supports the heat sink 110 vertically above the heating element 200. It is preferable that the support member 120 does not transmit the heat of the heating element 200 to the heat radiating plate 110. Therefore, the support member 120 is made using a highly heat-insulating material such as glass or ceramic.

  The heat transfer member 130 has a function of transferring the heat of the heating element 200 to the heat radiating plate 110. Therefore, a material having high thermal conductivity, for example, a metal such as aluminum can be used as the heat transfer member 130. On the other hand, the heat transfer member 130 does not contact the heat radiating plate 110 when the heat generating body 200 is low temperature, does not transmit heat to the heat radiating plate 110, and contacts the heat radiating plate 110 when the heat generating body 200 is high temperature. It is preferable that it is configured to transmit heat to. The heat transfer member 130 is in contact with the heating element 200 and expands or contracts by heat from the heating element 200. Due to the expansion and contraction, the heat transfer member 130 and the heat radiating plate 110 are in contact with or separated from each other. Therefore, a material having a large thermal expansion coefficient (linear expansion coefficient), for example, a metal such as aluminum can be used as the heat transfer member 130.

  FIG. 2 is an explanatory diagram when the heat dissipation device is viewed from vertically below and from above. FIG. 2A shows a schematic diagram when the heat dissipation device 100 is viewed from vertically below, and FIG. 2A shows a schematic diagram when the heat dissipation device 100 is viewed from vertically above. In the present embodiment, the support member 120 has a pipe shape (hollow cylindrical shape), and the heat transfer member 130 has a columnar shape. The heat transfer member 130 is disposed in the support member 120. As will be described later, the shape of the support member 120 and the heat transfer member 130 may be other than these shapes.

  Hereinafter, the operation of the heat dissipation device 100 will be described. When the heating element 200 is at a low temperature, the heat transfer member 130 is in contact with the heating element 200 but not in contact with the heat sink 110. When the temperature of the heating element 200 rises, the heat transfer member 130 receives heat from the heating element 200 and expands. When the temperature of the heat transfer member 130 reaches a certain temperature or higher, the heat transfer member 130 contacts the heat radiating plate 110 and transfers heat to the heat radiating plate 110.

The support member 120 is 5 cm thick glass (linear expansion coefficient 9 × 10 ⁻⁶ / K, thermal conductivity 1.38 W / cm · K), and the heat transfer member 130 is 5 cm thick aluminum (linear expansion coefficient 23.6). Suppose that the temperature of the heating element rose from 20 ° C. to 70 ° C. using × 10 ⁻⁶ , thermal conductivity 237 W / cm · K). Expansion of delta _gl glass at this time is 2.3 × 10 ^-2 mm, expansion amount delta _Al aluminum becomes 5.9 × 10 ^-2 mm. Therefore, Δ _Al > Δ _gl . Accordingly, the thicknesses of the support member 120 and the heat transfer member 130 can be determined so that the heat transfer member 130 contacts the heat radiating plate 110 when the temperature of the heating element 200 reaches 70 ° C.

  As described above, according to the first embodiment, the heat transfer member 130 is in contact with both the heat radiating plate 110 and the heating element 200 when the temperature of the heating element 200 is higher than a predetermined temperature. When the temperature is lower than a predetermined temperature, the heat sink 110 is separated. Therefore, when the heating element 200 is at a low temperature, the heat transfer to the heat radiating plate 110 is suppressed and the temperature of the heating element 200 is quickly increased. When the heating element 200 is at a high temperature, the heat transfer to the heat radiating plate 110 is performed. Heat can be promoted and released.

  FIG. 3 is an explanatory diagram showing the second embodiment. In the second embodiment, the heat dissipation device 100 of the first embodiment is applied to the fuel cell system 600. The fuel cell system 600 includes a plurality of power generation modules 610, end plates 620 and 625, an air filter 630, a compression pump 640, a pipe 650, and the heat dissipation device 100. The power generation modules 610 are stacked to form a fuel cell stack 615. End plates 620 and 625 are disposed at both ends of the fuel cell stack 615. The compression pump 640 compresses the air taken in through the air filter 630 and supplies the compressed air to the fuel cell stack 615 via the pipe 650. The compression pump 640 is connected to the end plate 625 by the support member 120 of the heat dissipation device 100. The compression pump 640 is also in contact with the heat transfer member 130 of the heat dissipation device 100. Before the fuel cell system 600 is started, the heat transfer member 130 is not in contact with the end plate 625. Here, the compression pump 640 corresponds to the heating element 200 shown in the first embodiment. In addition, the end plate 625 has a function as the heat radiating plate 110 because it is metallic and has high thermal conductivity. Note that the end plate 625 may include fins 627.

  Before the start of the fuel cell system 600, the compression pump 640 is not operating. Therefore, the temperature of the compression pump 640 is the same as the outside air temperature. At this time, the heat transfer member 130 is not in contact with the end plate 625. When the fuel cell system 600 is activated, the compression pump 640 is also activated, and the temperature of the compression pump 640 is increased. However, since the heat transfer member 130 is not in contact with the end plate 625, heat is not radiated to the end plate 625. Therefore, the temperature of the compression pump 640 rises quickly. For example, even at a low temperature at which the compression pump 640 freezes, the compression pump 640 can quickly increase the temperature. When the temperature of the compression pump 640 increases, the temperature of the heat transfer member 130 also increases, and the heat transfer member 130 expands thermally. When the temperature of the heat transfer member 130 exceeds a certain value, the heat transfer member 130 contacts the end plate 625. The heat transfer member 130 radiates heat to the end plate 625.

  According to the second embodiment, when the temperature of the compression pump 640 is low, the temperature of the compression pump 640 can be quickly raised, and when the temperature of the compression pump 640 is high, heat dissipation can be promoted. Therefore, the compression pump 640 can be operated at an optimum temperature. Moreover, since the end plate 625 can be used as a heat sink, the number of parts can be reduced.

  FIG. 4 is an explanatory diagram showing the third embodiment. The heat dissipation device 100 of the third embodiment is different from the first embodiment in that it includes a bimetal 300 for moving the heat transfer member 130. Further, the heat radiating plate 110 has an oblique bottom surface 114 and the heat transfer member 130 has a top surface 131 that can come into contact with the bottom surface 114 of the heat radiating plate 110. Both ends of the bimetal 300 are joined to the heating element 200 and the heat transfer member 130, respectively. The bimetal 300 is a laminate of two metals having different coefficients of thermal expansion. In this embodiment, of the two types of metals forming the bimetal 300, the one with the smaller thermal expansion coefficient is located on the heat transfer member 130 side, and the one with the larger thermal expansion coefficient is located on the support member 120 side.

  At low temperatures, the bimetal 300 is substantially flat. At this time, the heat transfer member 130 is in contact with the heating element 200 but not in contact with the heat sink 110. When the temperature of the heating element 200 rises, the heat is also transferred to the bimetal 300. The bimetal 300 warps to the heat transfer member 130 side when the temperature rises. Then, the heat transfer member 130 moves to the heat radiating plate 110 side, and the upper surface 131 of the heat transfer member 130 contacts the bottom surface 114 of the heat radiating plate 110. As a result, the heat of the heating element 200 is radiated from the heat radiating plate 110 via the heat transfer member 130.

  As described above, according to the third embodiment, using the warp of the bimetal 300, the heat transfer member 130 is brought into contact with both the heat radiating plate 110 and the heat generating element 200 when the heat generating element 200 is high temperature, and when the heat generating element 200 is low temperature. The heat transfer member 130 is separated from the heat radiating plate 110. As a result, when the heating element 200 is at a low temperature, heat transfer to the heat radiating plate 110 is suppressed and the temperature of the heating element 200 is quickly increased, and when the heating element 200 is at a high temperature, Heat transfer can be promoted and released. Further, in the third embodiment, since the warp due to the heat of the bimetal is used, the coefficient of thermal expansion of the heat transfer member 130 may not be large. Further, since it is not necessary to use the thermal expansion of the heat transfer member 130, the heat transfer member 130 and the heating element 200 may be separated from each other at a low temperature.

  FIG. 5 is an explanatory view showing a modification of the third embodiment. In this modification, an actuator 400 is provided for bringing the heat transfer member 130 into contact with or separating from the heat radiating plate 110. The bimetal 350 is connected to the heating element 200 and is used as a switch for controlling the operation direction of the actuator 400.

  According to this modification, the bimetal 350 is used as a switch, and the bimetal 350 itself does not move the heat transfer member 130. Therefore, it is not necessary to use a strong bimetal. Also, a large heat transfer member 130 can be used to promote heat transfer to the heat sink 110. In this modification, the bimetal 350 is used as the switch of the actuator 400, but other switches and other methods can also be used. For example, the heating element 200 may be provided with a temperature sensor. Further, when used in the fuel cell system as shown in the second embodiment, the heat transfer member 130 and the heat radiating member are brought into contact with the heat radiating plate 110 so that the heat transfer member 130 is brought into contact with the heat radiating plate 110 after a certain time has elapsed after the fuel cell system is started. The contact or separation with the plate 110 may be controlled by the time from activation.

  FIG. 6 is an explanatory diagram showing the fourth embodiment. In the fourth embodiment, a spring 500 that connects the support member 120 and the heat transfer member 130 is provided. The spring 500 is made of a bidirectional shape memory alloy. The spring 500 is contracted when the temperature is low, and the heat transfer member 130 and the heat radiating plate 110 are separated from each other. When the temperature of the heating element 200 increases, the temperature of the heat transfer member 130 increases. As a result, the temperature of the spring 500 rises. When the temperature of the spring 500 reaches the set temperature, the spring 500 expands to bring the heat transfer member 130 and the heat sink 110 into contact with each other due to the shape memory effect. On the other hand, when the temperature of the heating element 200 decreases, the temperature of the heat transfer member 130 also decreases, and the temperature of the spring 500 also decreases. When the temperature of the spring 500 falls below the set temperature, the heat transfer member 130 and the heat radiating plate 110 are separated by contracting.

  The spring 500 is made of, for example, a Ti—Ni alloy. Bidirectional shape memory alloys memorize the state of the austenite phase at a high temperature and memorize the state of the martensite phase at a low temperature. In order to memorize the bi-directional shape, it is generally known that an internal stress field may be introduced into the high temperature austenite phase. Specifically, it is possible to use a training method in which deformation is performed to the extent that shape recovery is possible and heating is repeated to recover the shape. In order to introduce an internal stress field into the high-temperature austenite phase, in addition to the training method, there is a strong processing method in which strong processing exceeding the limit is applied to the alloy, and a constrained heating method in which deformation, constrained fixation, and reverse transformation by heating are performed. It may be used.

  As described above, also in the fourth embodiment, the heat transfer member 130 is brought into contact with both the heat radiating plate 110 and the heat generating member 200 when the heat generating body 200 is high temperature, and the heat transfer member 130 and the heat radiating plate are used when the temperature is low. It is possible to separate from 110.

  FIG. 7 is an explanatory view showing a modification of the fourth embodiment. In the fourth embodiment, the spring 500 extends at a high temperature and contracts at a low temperature. In this modification, the spring 500 contracts at a high temperature and extends at a low temperature. As described above, the shape of the spring 500 may be memorized so as to extend at a high temperature, and conversely, the shape may be memorized so as to contract at a high temperature.

  FIG. 8 is an explanatory diagram showing a modification. In the first embodiment, the support member 120 has a pipe shape and the heat transfer member 130 has a columnar shape, but the support member 120 and the heat transfer member 130 have other shapes. Also good. In the example shown in FIG. 8A, the support member 120 is formed in a grid pattern in a cross section perpendicular to the heat transfer direction, and the heat transfer member 130 is disposed between the grid lines. . In the example shown in FIG. 8B, the support member 120 and the heat transfer member 130 are arranged so as to form a checkered pattern (checker pattern) in a cross section perpendicular to the heat transfer direction. As described above, various shapes can be adopted as the shape of the support member 120 and the heat transfer member 130.

  FIG. 9 is an explanatory diagram showing another modification. In this modification, the heat sink 110 is supported by the body 700 by the support member 120. As described above, the heat radiating plate 110 may not be directly supported by the heating element 200. For example, the heat radiating plate 110 may be indirectly supported so that the relative position between the heat radiating plate 110 and the heating element 200 does not change.

  FIG. 10 is an explanatory diagram showing another modification. As shown in this modification, the heat radiating plate 110 may be arranged in the horizontal direction instead of vertically above the heating element 200. However, as shown in FIG. 10 (A), it is preferable to fix the heating element 200 using a fastener 140.

  The embodiments of the present invention have been described above based on some examples. However, the above-described embodiments of the present invention are for facilitating the understanding of the present invention and limit the present invention. It is not a thing. The present invention can be changed and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.

DESCRIPTION OF SYMBOLS 100 ... Radiating device 110 ... Radiating plate 111 ... Fin 114 ... Bottom 120 ... Supporting member 130 ... Heat transfer member 131 ... Upper surface 140 ... Fastener 200 ... Heating element 300, 350 ... Bimetal 400 ... Actuator 500 ... Spring 600 ... Fuel cell system 610 ... Power generation module 615 ... Fuel cell stack 620, 625 ... End plate 627 ... Fin 630 ... Air filter 640 ... Compression pump 650 ... Piping 700 ... Body

Claims (6)

A heat dissipation device for dissipating the heat of the heating element,
A heat sink,
A support member for supporting the heat sink away from the heating element;
When the temperature of the heat generating element is lower than a predetermined temperature, the heat dissipating plate is separated from at least one of the heat generating element and the heat generating element. If the temperature is higher than a predetermined temperature, a heat transfer member that contacts both the heat sink and the heating element;
A moving member that is provided as a separate member from the heat transfer member and moves the heat transfer member;
Equipped with a,
The moving member is one of a bimetal, a bidirectional shape memory alloy, and an actuator,
The radiator plate has a bottom surface inclined with respect to the surface of the heating element;
The heat transfer member has a surface that can contact the bottom surface of the heat radiating plate,
When the temperature of the heating element is higher than a predetermined temperature, the moving member brings the heat transfer member into contact with both the heat radiating plate and the heating element, and the temperature of the heating element is determined in advance. If the temperature is lower than the above, the heat transfer member is separated from at least one of the heat radiating plate and the heating element,
The linear expansion coefficient of the heat transfer member is larger than the linear expansion coefficient of the support member,
Heat dissipation device.   A heat dissipation device for dissipating the heat of the heating element,
  A heat sink,
  A support member for supporting the heat sink away from the heating element;
  When the temperature of the heat generating element is lower than a predetermined temperature, the heat dissipating plate is separated from at least one of the heat generating element and the heat generating element. If the temperature is higher than a predetermined temperature, a heat transfer member that contacts both the heat sink and the heating element;
  A moving member that is provided as a separate member from the heat transfer member and moves the heat transfer member;
  With
  The moving member is one of a bimetal, a bidirectional shape memory alloy, and an actuator,
  The radiator plate has a bottom surface inclined with respect to the surface of the heating element;
  The heat transfer member has a surface that can contact the bottom surface of the heat radiating plate,
  When the temperature of the heating element is higher than a predetermined temperature, the moving member brings the heat transfer member into contact with both the heat radiating plate and the heating element, and the temperature of the heating element is determined in advance. If the temperature is lower than the above, the heat transfer member is separated from at least one of the heat radiating plate and the heating element,
  Heat dissipation device. In the heat radiating device according to claim 1 or claim 2,
The heat transfer member is a heat dissipation device in contact with the heating element. In the heat radiating device according to any one of claims 1 to 3,
The heat radiating device is a heat radiating device disposed vertically above the heating element. In the heat radiating device according to any one of claims 1 to 4,
The support member is connected to the heat sink and the heating element,
The heat dissipation device has a heat conductivity smaller than that of the heat transfer member. The heat dissipation device according to any one of claims 1 to 5 ,
The heat dissipation device is used in a fuel cell system that compresses a reaction gas using a pump and supplies the reaction gas to a fuel cell stack having an end plate.
The heating element is the pump;
The heat sink is the end plate.
Heat dissipation device.

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