JPWO2014156991A1 - Thermal switch, temperature control structure, and battery pack - Google Patents

Abstract

Provided are a heat switch having a simple structure capable of changing heat transfer performance depending on temperature, a temperature adjustment structure including the heat switch, and a battery pack. The thermal switch 1 is bonded to the first protective layer 2, the second protective layer 3 arranged to be paired with the first protective layer 2, and the side of the first protective layer 2 facing the second protective layer 3. The thermal expansion member 4 whose volume reversibly changes with temperature change, and the thermal expansion member 4 and the second protective layer 3 have a gap 5 without being in contact at normal temperature. The size of the gap 5 is determined so that the thermal expansion member 4 and the second protective layer 3 are in contact with each other by thermal expansion of the thermal expansion member 4 and can conduct heat.

Description

  The present invention relates to a thermal switch whose heat transfer performance varies with temperature, a temperature control structure including the thermal switch, and a battery pack.

In recent years, effective utilization of thermal energy has been required due to CO ₂ emission regulations and energy problems. In an apparatus or the like equipped with a heat generation source, heat may be required or unnecessary. For example, in a battery pack mounted on an EV, the resistance increases as the temperature decreases, so heat insulation is required at low temperatures, and if the temperature is too high, there is a concern of ignition due to decomposition of the electrolyte. Sex is required. Therefore, a technique for controlling the flow of heat is demanded as leading to effective use of heat.

  Such a technique includes an element (Patent Document 1) that switches a heat conduction state by applying energy (magnetic field, electric field, light, etc.) to a transition body sandwiched between electrodes, a substrate 1 and a carbon nanotube layer. The switch (patent document 2) which switches the connection state which the base material 2 which contacted and the non-connection state which does not contact is disclosed is disclosed.

International Publication No. 2004/068604 International Publication No. 2012/140927

  However, in Patent Document 1, an electrode, wiring, and the like are necessary to switch the switch by applying energy. In Patent Document 2, an actuator or the like is required to change the connection state of the switch. Therefore, in any invention, an additional member for operating the switch is essential in addition to the switch itself, the entire switch is enlarged, or the mounting location is limited from the viewpoint of heat resistance of the additional member, There was a problem.

  An object of the present invention is to provide a heat switch having a simple structure capable of changing the heat transfer performance by itself according to a temperature change, a temperature adjusting structure including the heat switch, and a battery pack.

  The present inventors have found that the above problem can be solved by using a thermal switch having a thermal expansion member whose volume reversibly changes with a temperature change. That is, according to the present invention, the following thermal switch, a temperature adjustment structure including the same, and a battery pack are provided.

[1] Temperature bonded to the first protective layer, the second protective layer arranged to be paired with the first protective layer, and the side of the first protective layer facing the second protective layer A thermal expansion member whose volume reversibly changes with a change, and the thermal expansion member and the second protective layer are opposed to each other with a gap without contact at room temperature, A thermal switch in which the size of the gap is determined so that the thermal expansion member and the second protective layer come into contact with each other by thermal expansion of the thermal expansion member and can conduct heat.

[2] The shortest distance between the side of the thermal expansion member facing the second protective layer and the side of the second protective layer facing the thermal expansion member is in the range of 0.1 to 100 μm. The thermal switch according to [1], wherein the size of the gap is defined.

[3] A first protective layer, a second protective layer disposed so as to be paired with the first protective layer, and a thermal expansion member whose volume reversibly changes with a temperature change, As the expansion member, a first thermal expansion member bonded to the side of the first protective layer facing the second protective layer, and a first bonded of the second protective layer to the side of the second protective layer facing the first protective layer The first thermal expansion member and the second thermal expansion member are opposed to each other with a gap without contacting each other at room temperature, and the first thermal expansion member and the second thermal expansion member A thermal switch in which the size of the gap is determined such that the second thermal expansion member comes into contact with each other and can conduct heat by thermal expansion of the first thermal expansion member and the second thermal expansion member.

[4] The size of the gap is determined so that the shortest distance between the first thermal expansion member and the second thermal expansion member adjacent to the first thermal expansion member is in a range of 0.1 to 100 μm. The thermal switch according to [3].

[5] The thermal switch according to any one of [1] to [4], wherein the thermal expansion member includes a plurality of independent convex thermal expansion members as at least a part thereof.

[6] The thermal expansion member is formed of a material whose dimensions increase or decrease by 0.1% or more when the temperature changes from an arbitrary temperature T ° C. to T ± 100 ° C. ] The thermal switch in any one of.

[7] The thermal expansion member has an average linear thermal expansion coefficient in the range of 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ / K when the temperature changes from 40 ° C. to 400 ° C. 6] The thermal switch according to any one of the above.

[8] The thermal switch according to any one of [1] to [7], wherein the thermal expansion member is formed of a material whose volume gradually increases or decreases according to a temperature change.

[9] The thermal expansion member according to [8], wherein an average linear thermal expansion coefficient when the temperature is changed from 40 ° C. to 800 ° C. is in a range of 7 × 10 ⁻⁶ to 1 × 10 ⁻⁴ / K. Thermal switch.

[10] In the above [8] or [9], the thermal expansion member is formed by any one selected from the group consisting of zirconia, alumina, spinel, magnesia, calcia, titania, yttria, forsterite, and enstatite. The described thermal switch.

[11] The material forming the thermal expansion member is any one of the above [1] to [7], which is a material whose coefficient of thermal expansion changes abruptly with a phase transition at a temperature unique to the material. The thermal switch described in.

[12] The material according to [11], wherein the material forming the thermal expansion member is a material whose size increases or decreases by 0.1% or more with a phase transition at a temperature inherent to the material. Thermal switch.

[13] The thermal expansion member is made of SiO ₂ (Cristobalite), Ba, Sr hexacelsian ((BaO _x Sr _1-x ) O · Al ₂ O ₃ · 2SiO ₂ (0 <x <1)), Ca, Sr hexacelsian _{((CaO x Sr 1-x} ) O · Al 2 O 3 · 2SiO 2 (0 <x <1)), the formed by one selected from the group consisting of AuCu alloy [11] Or the thermal switch as described in [12].

[14] The thermal switch according to any one of [1] to [13], wherein the first protective layer and the second protective layer are formed of a material having a thermal conductivity of 1 to 500 W / mK.

[15] The [1] to [1], wherein the first protective layer and the second protective layer are formed of any one selected from the group consisting of metals or ceramics made of oxide, nitride, or carbide. [14] The thermal switch according to any one of [14].

[16] The thermal switch according to any one of [1] to [15], wherein the first protective layer and the second protective layer are coupled to each other by a coupling means having heat insulation properties.

[17] The thermal switch according to any one of [1] to [16] is provided around a heat generation source that generates heat, and includes a first temperature and a second temperature higher than the first temperature. The temperature adjustment structure which adjusts the temperature resulting from the heat of the said heat generation source by changing a heat dissipation state between.

[18] A battery pack having the temperature adjustment structure according to [17].

  The thermal switch of the present invention has a heat insulating effect because it is in a disconnected state (off state) at room temperature or low temperature, and has a heat dissipating effect because it generates a connected state (on state) that can conduct heat by thermal expansion at high temperatures. It operates as a self-supporting thermal switch.

  As described above, the thermal switch of the present invention can change the heat transfer performance itself according to a change in ambient temperature, and thus does not require additional parts such as an energy applying unit and a driving unit, and the entire switch is small. Can be In addition, it is highly mountable and has a high degree of freedom in shape. The temperature adjustment structure provided with the heat switch of the present invention has a remarkable effect in that the internal heat is effectively used and the function of the heat generation source is improved, particularly in a heat generation source such as a battery pack. .

It is typical sectional drawing which shows Embodiment 1 of the thermal switch of this invention. It is typical sectional drawing which shows Embodiment 2 of the thermal switch of this invention. It is typical sectional drawing which shows Embodiment 3 of the thermal switch of this invention. It is typical sectional drawing which shows Embodiment 4 of the thermal switch of this invention. It is a schematic diagram which shows one Embodiment of the formation method of a gap | interval. It is a schematic diagram which shows other embodiment of the formation method of a gap | interval. It is a schematic diagram which shows one Embodiment of the battery pack of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be added without departing from the scope of the invention.

  FIG. 1 is a schematic cross-sectional view showing Embodiment 1 of the thermal switch of the present invention. The left diagram in FIG. 1 shows the thermal switch 1 (1a) in the unconnected state (off state), and the right diagram in FIG. 1 shows the thermal switch 1 (1b) in the connected state (on state). The thermal switch 1 of the present invention faces the second protective layer 3 of the first protective layer 2, the second protective layer 3 arranged to be paired with the first protective layer 2, and the first protective layer 2. And a thermal expansion member 4 whose volume is reversibly changed with a change in temperature. As shown in FIG. 1, at the normal temperature, the thermal expansion member 4 and the second protective layer 3 are opposed to each other with a gap 5 without contact. At this time, it is difficult to exchange heat between the thermal expansion member 4 and the second protective layer 3, and the switch 1 (1a) is in a disconnected state (off state). On the other hand, when the ambient temperature rises, the thermal expansion member 4 thermally expands, so that the thermal expansion member 4 and the second protective layer 3 come into contact with each other. At this time, the heat transfer rate between the thermal expansion member 4 and the second protective layer 3 rapidly increases, and the switch 1 (1b) is in a connected state (ON state). Since the thermal expansion member 4 is formed of a material whose volume reversibly changes with a change in temperature, when the ambient temperature decreases again, the contraction state of the thermal expansion member 4 with the second protective layer 3 is reduced. It is unwound and the gap 5 is generated again. At this time, the switch 1 (1a) is again disconnected (off state).

  The size of the gap 5 is related to the material characteristics of the thermal expansion member 4 and the usage environment so that the thermal expansion member 4 and the second protective layer 3 can be brought into contact with each other by the thermal expansion of the thermal expansion member 4 and can conduct heat. It is determined according to. The size of the gap 5 is not particularly limited as long as it satisfies the above requirements, but the side of the thermal expansion member 4 facing the second protective layer 3 and the thermal expansion member of the second protective layer 3 are not limited. 4 is preferably in the range of 0.1 to 100 μm, and more preferably in the range of 1 to 100 μm. If the distance is less than 0.1 μm, the thermal expansion member 4 and the second protective layer 3 are excessively contacted in the connected state (ON state), and stress may be generated in both of them, which may be damaged. . Further, if the distance exceeds 100 μm, the contact state between the thermal expansion member 4 and the second protective layer 3 may be insufficient in the connected state (on state), which is not preferable. The gap 5 is preferably a vacuum, but may be filled with a gas such as air.

  FIG. 2 is a schematic cross-sectional view showing Embodiment 2 of the thermal switch of the present invention. 2 shows the thermal switch 11 (11a) in the non-connected state (off state), and the right diagram in FIG. 2 shows the thermal switch 11 (11b) in the connected state (on state). The thermal switch 11 of the present invention includes a first protective layer 2, a second protective layer 3 disposed so as to be paired with the first protective layer 2, and a thermal expansion member whose volume reversibly changes with a temperature change. 4. The thermal expansion member 4 is bonded to the first thermal expansion member 4 a bonded to the side of the first protective layer 2 facing the second protective layer 3 and to the side of the second protective layer 3 facing the first protective layer 2. Second thermal expansion member 4b. As shown in FIG. 2, at normal temperature, the first thermal expansion member 4a and the second thermal expansion member 4b face each other with a gap 15 without contacting each other. At this time, it is difficult to exchange heat between the first thermal expansion member 4a and the second thermal expansion member 4b, and the switch 11 (11a) is in a disconnected state (off state). On the other hand, when the ambient temperature rises, the first thermal expansion member 4a and the second thermal expansion member 4b thermally expand, so that the first thermal expansion member 4a and the second thermal expansion member 4b come into contact with each other. At this time, the heat transfer rate between the first thermal expansion member 4a and the second thermal expansion member 4b rapidly increases, and the switch 11 (11b) is in the connected state (ON state). Since the thermal expansion member 4 is formed of a material whose volume reversibly changes with a temperature change, when the ambient temperature decreases again, the first thermal expansion member 4a and the second thermal expansion member 4b By contraction, the contact state with each other is released, and the gap 15 is generated again. At this time, the switch 11 (11a) is again disconnected (off state).

  The size of the gap 15 depends on the relationship between the material characteristics of the thermal expansion member 4 and the usage environment so that the first thermal expansion member 4a and the second thermal expansion member 4b can contact each other by thermal expansion and can conduct heat. It is determined accordingly. The size of the gap 15 is not particularly limited as long as it satisfies such a requirement, but the first thermal expansion member 4a and the second thermal expansion member 4b adjacent to the first thermal expansion member 4a The shortest distance is preferably in the range of 0.1 to 100 μm, and more preferably in the range of 1 to 100 μm. If the above distance is less than 0.1 μm, the first thermal expansion member 4a and the second thermal expansion member 4b may be excessively contacted in the connected state (on state), and stress may be generated in both of them to cause damage. Therefore, it is not preferable. In addition, if the distance exceeds 100 μm, the contact state between the first thermal expansion member 4a and the second thermal expansion member 4b may be insufficient in the connected state (on state), which is not preferable. The gap 15 is preferably a vacuum, but may be filled with a gas such as air.

  As described above, the thermal switches 1 and 11 of the present invention can be switched on / off by themselves according to a change in ambient temperature. Therefore, the thermal switches 1 and 11 are indispensable for conventional thermal switches such as energy applying means and driving means. The additional parts which were were not required. Therefore, the thermal switches 1 and 11 of the present invention can be remarkably reduced in size as compared with the conventional switches, and there is no need to consider the heat resistance of the additional components. Therefore, when the thermal switches 1 and 11 of the present invention are used as a heat generation source such as an engine or a battery pack, it is possible to greatly improve the mountability and the freedom of shape.

  The thermal expansion member 4 in the thermal switches 1 and 11 of the present invention may include a plurality of convex thermal expansion members that are independent from each other as at least a part thereof. The shape, the number, the forming method, and the like of the convex thermal expansion member are not particularly limited as long as the switch function surely functions according to the temperature change. FIG. 3 is a schematic cross-sectional view showing Embodiment 3 of the thermal switch of the present invention. In the thermal switch 1 of the present invention, the thermal expansion member 4 is composed of a plurality of convex thermal expansion members 4c that are independent from each other. Is shown. FIG. 4 is a schematic cross-sectional view showing Embodiment 4 of the thermal switch of the present invention. In the thermal switch 11 of the present invention, each of the first thermal expansion member 4a and the second thermal expansion member 4b is independent of each other. An example of a plurality of convex thermal expansion members 4c is shown. As shown in FIG. 4, when the convex thermal expansion member 4c is needle-shaped, a plurality of convex thermal expansion members 4c are evenly bonded to the first protective layer 2 and the second protective layer 3, Moreover, it is preferable that the convex thermal expansion members 4c are arranged so as to overlap each other with the gap 15 in a direction perpendicular to each extending direction. That is, at this time, the gap 15 which is the shortest distance between the first thermal expansion member 4a and the second thermal expansion member 4b adjacent to the first thermal expansion member 4a is a direction perpendicular to the extending direction of the convex thermal expansion member 4c. Formed.

  The thermal expansion member 4 is a material whose volume reversibly changes with a change in temperature, and when the temperature changes from an arbitrary temperature T ° C. to T ± 100 ° C., the dimension increases by 0.1% or more or Preferably formed from a decreasing material. If the dimensional change of the material when the temperature changes from an arbitrary temperature T ° C. to T ± 100 ° C. is less than 0.1%, the thermal expansion member 4 may not function as a switch in actual use, which is not preferable.

The thermal expansion member 4 more preferably has an average linear thermal expansion coefficient in the range of 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ / K when the temperature changes from 40 ° C. to 400 ° C. If the average linear thermal expansion coefficient when the temperature changes from 40 ° C. to 400 ° C. is less than 5 × 10 ⁻⁶ / K, the dimensional change of the thermal expansion member 4 may be too small to function as a switch in actual use. This is not preferable. When the average linear thermal expansion coefficient when the temperature changes from 40 ° C. to 400 ° C. exceeds 5 × 10 ⁻⁴ / K, the dimensional change of the thermal expansion member 4 is too large and the thermal expansion member 4 is joined. This is not preferable because the protective layers 2 and 3 may be damaged.

The thermal expansion member 4 may be formed of a material whose volume gradually increases or decreases according to a temperature change. Specifically, the thermal expansion member 4 may have an average linear thermal expansion coefficient in the range of 7 × 10 ⁻⁶ to 1 × 10 ⁻⁴ / K when the temperature changes from 40 ° C. to 800 ° C. Examples of the material of the thermal expansion member 4 include zirconia, alumina, spinel, magnesia, calcia, titania, yttria, forsterite, enstatite, and the like. Such a material does not suddenly undergo volume expansion as soon as it reaches a specific temperature range. Therefore, in the thermal switches 1 and 11 using such a material as the thermal expansion member 4, the thermal switches 1 and 11 corresponding to the use environment and usage purpose can be obtained by variously combining the materials and the sizes of the gaps 5 and 15. 11 can be obtained.

Further, the material forming the thermal expansion member 4 may be a material whose thermal expansion coefficient changes abruptly with phase transition at the temperature inherent to the material. Specifically, the material forming the thermal expansion member 4 may be a material whose size increases or decreases by 0.1% or more with a phase transition at the temperature inherent to the material. As a material for the thermal expansion member 4, SiO ₂ (cristobalite), Ba, Sr hexacelsian _{((BaO x Sr 1-x} ) O · Al 2 O 3 · 2SiO 2 (0 <x <1)) , Ca, Sr hexacelsian _{((CaO x Sr 1-x} ) O · Al 2 O 3 · 2SiO 2 (0 <x <1)), AuCu alloy, and the like. For example, Ba, Sr hexacelsian is a material whose thermal expansion coefficient changes abruptly around about 300 ° C. In the thermal switches 1 and 11 using such a material as the thermal expansion member 4, the switches 1 and 11 are switched on / off in a temperature region unique to the material. Therefore, by selecting the type and composition of the material used as the thermal expansion member 4, it is possible to obtain the thermal switches 1 and 11 corresponding to the usage environment and usage purpose.

  The first protective layer 2 and the second protective layer 3 in the thermal switches 1 and 11 of the present invention have a function of protecting the thermal expansion member 4 from physical damage and chemical damage. Physical damage refers to thermal shock when used where an unsteady thermal history is applied, damage due to sliding when used in an operating part, and the like. Chemical damage refers to corrosion or deterioration when used in an oxidizing atmosphere. The material for forming the first protective layer 2 and the second protective layer 3 is not particularly limited as long as it satisfies the above requirements and has thermal conductivity. However, it is preferable that the material has a higher thermal conductivity. . Specifically, the first protective layer 2 and the second protective layer 3 are preferably formed of a material having a thermal conductivity of 1 to 500 W / mK. The higher the thermal conductivity of the material, the larger the change ratio of the apparent thermal conductivity when the switch is OFF and ON. Moreover, it is preferable that the material which forms the 1st protective layer 2 and the 2nd protective layer 3 is formed with the ceramics which consist of a metal or an oxide, nitride, or a carbide | carbonized_material. Specifically, metals such as Al, Ti, Mn, Fe, Ni, Cu, Mo, Ag, W, Au, Pt, and alloys thereof, and silicon carbide, aluminum nitride, alumina, silicon nitride, sialon, And ceramics such as yttria.

  In the thermal switches 1 and 11 of the present invention, the method of providing the gaps 5 and 15 in a predetermined size is not particularly limited as long as the heat insulation state is maintained in the off state. FIG. 5A is a schematic diagram showing an embodiment of a gap forming method, and FIG. 5B is a schematic diagram showing another embodiment of a gap forming method. As a method of forming the gaps 5 and 15 in the thermal switches 1 and 11 of the present invention, for example, as shown in FIG. 5A, a method of fixing the entire switch 1 using a heat insulating member 8 that is a connecting means having heat insulating properties, Or the method of fixing the 1st protective layer 2 and the 2nd protective layer 3 using the heat insulation member 8 as shown in FIG. 5B, etc. are mentioned.

  Next, a temperature adjustment structure in which the thermal switches 1 and 11 of the present invention are provided around a heat generation source that generates heat will be described. In this specification, the temperature adjustment structure refers to the function of the heat generation source by adjusting the temperature while effectively using the heat from the heat generation source including the thermal switches 1 and 11 of the present invention. Refers to a structure that can be improved. Here, the heat generation source means one that generates heat, and is not particularly limited. The temperature adjustment structure of the present invention includes a temperature adjustment structure that adjusts the temperature due to heat of the heat generation source by changing the heat radiation state between the first temperature and the second temperature higher than the first temperature. The performance of the apparatus can be improved. Therefore, the temperature adjustment structure of the present invention is preferably used in a heat generation source in which the temperature becomes irregularly high during use. Specific examples of such a heat generation source include a battery pack, a motor, a CPU, a control circuit, an engine, a brake, a gear box, and the like. A structure including the heat switches 1 and 11 around these heat generation sources is a temperature adjustment structure. Moreover, when sunlight is used as the heat generation source, it is possible to provide a temperature adjustment structure that adjusts the indoor temperature by providing the building materials, windows, sashes, and the like with the thermal switches 1 and 11.

  FIG. 6 is a schematic view showing an embodiment of the battery pack of the present invention. The battery pack 30 is a heat generation source. As shown in FIG. 6, the battery pack 30 of the present invention includes a plurality of batteries, and these are electrically connected and accommodated in a case 31. In addition, thermal switches 1 and 11 are provided around the battery pack 30, that is, in the case 31.

  The battery pack 30 has a high battery resistance because it is at a low temperature when it is started. Therefore, it is preferable that the heat inside the battery pack 30 is not radiated as much as possible. On the other hand, it is preferable to actively dissipate the heat inside the battery pack 30 because the temperature inside the battery pack 30 becomes high after the warm-up is completed, and there is a concern of ignition due to decomposition of the electrolyte. Since the heat switches 1 and 11 provided in the battery pack 30 of the present invention are in a disconnected state (off state) when the battery pack 30 is started, it is difficult to dissipate the heat inside the battery pack 30 and the heat is used effectively. be able to. On the other hand, after the warm-up is completed, the internal temperature of the battery pack 30 rises, the thermal switches 1 and 11 are connected (on state), and the heat transfer efficiency increases rapidly. Can be released to the outside.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.

Example 1
A cordierite (first protective layer 2) is bonded to one side of a plate-like zirconia (thermal expansion member 4), and another cordierite (second protective layer 3) is formed while providing a gap 5 of 3 μm on the other side. The thermal switch 1 in which is disposed) was produced. The way of heat transfer as the whole member (thermal switch 1) was evaluated using a heat flow meter. Specifically, the temperature of one cordierite (first protective layer 2) is adjusted to be attached to the other cordierite (second protective layer 3) when adjusted to 25 ° C and 90 ° C. The heat flow through the heat flow sensor was measured.

  Assuming that the heat flow rate when the heat switch 1 is off, that is, 25 ° C., is 100, the heat flow rate when the heat switch 1 is turned on, ie, 90 ° C., is 1200, confirming that it functions as a switch.

(Example 2)
Same as the first joined body in which a plurality of needle-shaped zirconia (first thermal expansion member 4a (convex thermal expansion member 4c)) are evenly bonded to one side of the plate-shaped cordierite (first protective layer 2). A second joined body in which a plurality of needle-like zirconia (second thermal expansion member 4b (convex thermal expansion member 4c)) are evenly joined to one side of a plate-shaped cordierite (second protective layer 3) is produced. did. Next, the first joined body and the second joined body are arranged so that the surfaces to which the zirconia is joined face each other, and the zirconia extending from the first joined body (first thermal expansion member 4a (convex thermal expansion member 4c). )) And zirconia (second thermal expansion member 4b (convex thermal expansion member 4c)) extending from the second joined body, a thermal switch 11 having a 3 μm gap 15 was produced. The way of heat transfer as the whole member (thermal switch 11) was evaluated using a heat flow meter. Specifically, the temperature of one cordierite (first protective layer 2) is adjusted to be attached to the other side cordierite (second protective layer 3) when adjusted to 25 ° C and 90 ° C. The heat flow through the heat flow sensor was measured.

  Assuming that the heat flow rate when the heat switch 11 is off, that is, at 25 ° C., is 100, the heat flow rate when the heat switch 1 is turned on, ie, at 90 ° C., is 1200, confirming that it functions as a switch.

  The thermal switch of the present invention can be used as a switch whose heat transfer performance varies depending on the temperature. For example, by providing the heat switch of the present invention in a heat generation source such as a battery pack, the heat of the heat generation source can be effectively recovered or radiated.

1, 1a, 1b, 11, 11a, 11b: thermal switch, 2: first protective layer, 3: second protective layer, 4: thermal expansion member, 4a: first thermal expansion member, 4b: second thermal expansion member 4c: convex thermal expansion member, 5, 15: gap, 8: heat insulating member, 30: battery pack, 31: case.

Claims (18)

A first protective layer;
A second protective layer arranged to be paired with the first protective layer;
A thermal expansion member that is bonded to the side of the first protective layer facing the second protective layer and whose volume reversibly changes with a temperature change,
The thermal expansion member and the second protective layer are opposed to each other with a gap without contact at room temperature,
The thermal switch in which the size of the gap is determined so that the thermal expansion member and the second protective layer are in contact with each other by thermal expansion of the thermal expansion member and can conduct heat.   The gap is set so that the shortest distance between the side of the thermal expansion member facing the second protective layer and the side of the second protective layer facing the thermal expansion member is in the range of 0.1 to 100 μm. The thermal switch of claim 1, wherein the size is defined. A first protective layer;
A second protective layer arranged to be paired with the first protective layer;
A thermal expansion member whose volume reversibly changes with a temperature change, and
As the thermal expansion member,
A first thermal expansion member joined to a side of the first protective layer facing the second protective layer;
A second thermal expansion member joined to a side of the second protective layer facing the first protective layer,
The first thermal expansion member and the second thermal expansion member are opposed to each other with a gap without contacting each other at room temperature,
The size of the gap is determined so that the first thermal expansion member and the second thermal expansion member come into contact with each other and can conduct heat by thermal expansion of the first thermal expansion member and the second thermal expansion member. Thermal switch.   The size of the gap is determined so that the shortest distance between the first thermal expansion member and the second thermal expansion member adjacent to the first thermal expansion member is in a range of 0.1 to 100 μm. Item 4. The thermal switch according to item 3.   The thermal switch according to any one of claims 1 to 4, wherein the thermal expansion member includes a plurality of convex thermal expansion members that are independent from each other as at least a part thereof.   The said thermal expansion member is formed from the material from which the dimension increases or decreases 0.1% or more when temperature changes from arbitrary temperature T degree C to T +/- 100 degreeC. The thermal switch described in. 7. The thermal expansion member has an average linear thermal expansion coefficient in the range of 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ / K when the temperature changes from 40 ° C. to 400 ° C. 7. The thermal switch according to item.   The thermal switch according to any one of claims 1 to 7, wherein the thermal expansion member is formed of a material whose volume gradually increases or decreases according to a temperature change. The thermal switch according to claim 8, wherein the thermal expansion member has an average linear thermal expansion coefficient in a range of 7 × 10 ⁻⁶ to 1 × 10 ⁻⁴ / K when the temperature changes from 40 ° C. to 800 ° C. 9.   The thermal switch according to claim 8 or 9, wherein the thermal expansion member is formed of any one selected from the group consisting of zirconia, alumina, spinel, magnesia, calcia, titania, yttria, forsterite, and enstatite.   The heat according to any one of claims 1 to 7, wherein the material forming the thermal expansion member is a material whose thermal expansion coefficient changes rapidly with a phase transition at a temperature unique to the material. switch.   The thermal switch according to claim 11, wherein the material forming the thermal expansion member is a material whose dimension increases or decreases by 0.1% or more with a phase transition at a temperature specific to the material. The thermal expansion member is made of SiO ₂ (Cristobalite), Ba, Sr hexacelsian ((BaO _x Sr _1-x ) O · Al ₂ O ₃ · 2SiO ₂ (0 <x <1)), Ca, Sr hexacel cyan _{((CaO x Sr 1-x} ) O · Al 2 O 3 · 2SiO 2 (0 <x <1)), according to claim 11 or 12 formed by any one selected from the group consisting of AuCu alloy Thermal switch.   The thermal switch according to any one of claims 1 to 13, wherein the first protective layer and the second protective layer are formed of a material having a thermal conductivity of 1 to 500 W / mK.   The said 1st protective layer and the said 2nd protective layer are any one of Claims 1-14 formed from the group which consists of ceramics which consist of a metal or an oxide, a nitride, or a carbide | carbonized_material. The thermal switch according to item.   The thermal switch according to any one of claims 1 to 15, wherein the first protective layer and the second protective layer are connected to each other by a connecting means having heat insulation properties. The thermal switch according to any one of claims 1 to 16 is provided around a heat generation source that generates heat,
A temperature adjustment structure that adjusts a temperature caused by heat of the heat generation source by changing a heat dissipation state between a first temperature and a second temperature higher than the first temperature.   A battery pack having the temperature adjustment structure according to claim 17.

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