JP2000031361A - Cooler by boiling and condensing coolant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooler by boiling and condensing coolant capable of keeping a given level of radiating performance even if a container leaks. SOLUTION: A cooler 1 by boiling and condensing coolant includes a heat conducive part 5 for joining a coolant container 3 and a heat radiator 4 thermally. The heat conductive part 5 is made of metal like aluminum or copper with good heat conductivity. The heat conductive part 5 includes a main heat conductive part 5A passed through a lower tank 14 of the radiator 4 and arranged vertically at the center of a core part 12, subsidiary heat conductive parts 5B provided at intervals at almost all part of the core part 12 and arranged in parallel with the main heat conductive part 5A, and a joining part 5C put horizontally at a central part of the vertical core part 12 for joining the main heat conductive part 5A and a plurality of subsidiary heat conductive part 5B. In this constitution, heat transfer is carried out from the cooling container 3 to the radiator 4 through the heat conductive part 5 even if the cooler 1 by boiling and condensing coolant leaks.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boiling cooling device for cooling a heating element such as a semiconductor element used in an inverter circuit of an electric vehicle.

[0002]

2. Description of the Related Art As a prior art, for example, Japanese Patent Laid-Open No.
There is a boiling cooling device described in Japanese Patent No. 4075. In this boiling cooling device, a refrigerant is sealed in a highly airtight container having a boiling portion and a condensing portion, and the heating element is cooled by heat transport by repeating boiling and condensation of the refrigerant.

[0003]

However, in the conventional boiling cooling apparatus, when a minute crack or the like is generated in a highly airtight container and an airtight leak occurs, the refrigerant vapor boiling due to the heat of the heating element is generated in the container. Since the refrigerant leaks to the outside, the refrigerant sealed in the container cannot circulate through the evaporator and the condenser. As a result, it becomes impossible to transfer the heat of the heating element from the evaporating section to the heat radiating section, so that the function as the cooling device is lost and the heating element cannot be cooled. The present invention has been made based on the above circumstances, and an object of the present invention is to provide a boiling cooling device capable of maintaining a certain degree of heat radiation performance even when airtight leakage occurs in a container.

[0004]

According to the first aspect of the present invention, there is provided a boiling cooling apparatus in which a refrigerant tank and a radiator are thermally connected to each other to transfer heat from the refrigerant tank to the radiator by heat conduction. A heat transfer unit that can perform the heat transfer is provided. According to this configuration, even if airtight leakage occurs in the container (refrigerant tank and radiator) in which the refrigerant is sealed and heat transfer due to boiling and condensation of the refrigerant becomes impossible, the radiator is transferred from the refrigerant tank through the heat transfer unit. The heat of the heating element can be transferred (heat conduction). As a result, even if airtight leakage occurs in the container, a certain degree of heat radiation performance can be ensured, so that a rapid rise in temperature of the heating element can be suppressed.

[0005] (Means of the second aspect) The heat transfer portion can transfer heat from the refrigerant tank to substantially the entire radiator. In this case, since the entire radiator can be used effectively, the heat radiation performance by heat conduction can be improved.

(Means of Claim 3) The heat transfer portion is provided by extending a part of the extruded material constituting the refrigerant tank to the radiator. In this case, the heat transfer section can be integrally formed from the refrigerant tank to the radiator, and there is no need to provide a joint between the refrigerant tank and the radiator in the heat transfer section. This makes it possible to reduce the thermal resistance of the heat transfer section as compared with the case where the joint is provided, so that the heat dissipation performance can be further improved.

[0007]

Next, an embodiment of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is a front view (a) and a side view (b) of a boiling cooling device 1. The boiling cooling device 1 cools a heating element 2 (semiconductor element) such as an IGBT module constituting an inverter circuit of an electric vehicle, for example, as shown in FIG. 1, a refrigerant tank 3 for storing a liquid refrigerant therein, A radiator 4 provided above the refrigerant tank 3 and a heat transfer unit 5 capable of transferring heat from the refrigerant tank 3 to the radiator 4 by heat conduction.
And As shown in FIG. 1B, the heating element 2 is tightly fixed to both surfaces of the refrigerant tank 3 by tightening bolts 6.

The refrigerant tank 3 comprises a hollow container 7 made of a metal material having excellent thermal conductivity such as aluminum, and an end tank 8 covered on the lower end of the hollow container 7. Liquid return passage 10 and reflux passage 1
1 is formed. The hollow container 7 is, for example, an extruded product, as shown in FIG. 2, provided in a flat shape having a small thickness with respect to the width, and a plurality of partition walls 7 a inside the container.
7b and 7c are left. The end tank 8 is made of, for example, the same aluminum as the hollow container 7 and has the shape shown in FIG.
{(A) is a top view, (b) is a side view, and (c) is a sectional view taken along line AA}. The end tank 8 is joined to the lower end of the hollow container 7 by brazing or the like, and closes the lower end of the hollow container 7. However, a space is secured between the lower end surface of the hollow container 7 and the inside of the end tank 8 as shown in FIG.

The refrigerant chamber 9 is formed between one partition wall 7a located at the center of the hollow container 7 and a pair of partition walls 7b located on both right and left sides, and the inside thereof has a plurality of partition walls. 7c define a passage. This refrigerant chamber 9
Defines a boiling region in which the liquid refrigerant stored therein receives heat from the heating element 2 and boils. The liquid return passage 10 is a passage through which the condensed liquid condensed by the radiator 4 flows, and is formed outside the partition wall 7b. The recirculation passage 11 is a passage for supplying the condensed liquid flowing into the liquid return passage 10 to the refrigerant chamber 9, and is formed by the inner space of the end tank 8. 9 is communicated.

The radiator 4 includes a core 12 and an upper tank 1.
3 and a lower tank 14. Core part 1
Numeral 2 is a heat radiating unit for condensing and liquefying the refrigerant vapor boiling by receiving heat from the heat generating element 2 with an external fluid (for example, air).
6 are alternately arranged, and the heat radiating tubes 15 are used in a state of standing in the vertical direction. The heat radiating tube 15 is, for example, a flat tube made of aluminum, and has an inner fin 17 inserted therein (see FIG. 9). The radiation fins 16 are corrugated fins formed by alternately bending thin metal plates (for example, aluminum plates) having excellent thermal conductivity and forming them into a wave shape.

The upper tank 13 is constituted by combining an aluminum core plate 18 and a tank plate 19, for example, and is connected to the upper end of each heat radiation tube 15. 4 (a) is a plan view, (b) is a side view, and FIG. 5 (a) is a top view, (b) is a side view, and (c) is a view showing the shapes of the core plate 18 and the tank plate 19, respectively. B-
It is shown in section B of FIG. The core plate 18 has a large number of long holes 18a into which the ends of the heat radiation tubes 15 are inserted. The lower tank 14 is configured by combining an aluminum core plate 20 and a tank plate 21, for example, and is connected to the lower end of each heat radiation tube 15. FIGS. 6A and 6B show the shapes of the core plate 20 and the tank plate 21, respectively.
{(A) is a side view, (b) is a top view, and (c) is a CC cross-sectional view}. The core plate 20 has the same shape as the core plate 18 of the upper tank 13,
Are formed with a number of long holes 20a into which the ends of the long holes 20a are inserted.
The tank plate 21 has an elongated hole 21a into which the upper end of the refrigerant tank 3 (hollow container 7) is inserted.

The heat transfer section 5 thermally couples the refrigerant tank 3 and the radiator 4, and includes one main heat transfer section 5A, a plurality of sub heat transfer sections 5B, and a main heat transfer section 5A. And a connecting portion 5C connecting the auxiliary heat transfer portion 5B to the auxiliary heat transfer portion 5B, and is formed of a metal material having excellent thermal conductivity (for example, aluminum, copper, or the like). The main heat transfer section 5A is disposed vertically in the center of the core section 12 through the lower tank 14 of the radiator 4, and has a lower end surface located at the center of the refrigerant tank 3 (hollow container 7). It is joined to the upper end surface of the wall 7a by brazing (see FIG. 8).
The sub heat transfer sections 5B are spaced apart from each other by
It is arranged on substantially the entire core portion 12 in parallel with A. Also,
As shown in FIG. 9, the heat radiating tube 1 is provided in the sub heat transfer portion 5B.
5 are built in, and the radiation fins 16 are interposed between the adjacent sub heat transfer sections 5B. The connecting portion 5C is disposed laterally at a substantially central portion in the vertical direction of the core portion 12, and thermally connects the main heat transfer portion 5A and the plurality of sub heat transfer portions 5B. In addition,
The main heat transfer section 5A, the sub heat transfer section 5B, and the connecting section 5C may be joined to each other by brazing or the like. Is good.

Next, the operation of this embodiment will be described. a) A case where no airtight leak has occurred in the boiling cooling device 1. The heat generated from the heating element 2 is transmitted to the liquid refrigerant stored in the refrigerant chamber 9 through the wall surface of the refrigerant tank 3 (hollow container 7), and the liquid refrigerant boils. The boiling refrigerant becomes vapor and rises in the refrigerant chamber 9, flows from the refrigerant chamber 9 through the lower tank 14, and flows into each heat radiation tube 15 of the core 12. The refrigerant vapor flowing into the heat radiating tube 15 is cooled by heat exchange with the outside air when flowing through the heat radiating tube 15 and releases latent heat to release the inner wall surface of the heat radiating tube 15 and the inner fin 17.
Condenses on the surface. The latent heat released when the refrigerant vapor is condensed is transmitted from the wall surface of each heat radiation tube 15 to the heat radiation fins 16 mainly through the sub heat transfer portion 5B, and is released from the heat radiation fins 16 to the outside air. The condensed liquid condensed into droplets in the heat radiating tube 15 flows downward along the inner wall surface of the heat radiating tube 15 and the surface of the inner fin 17,
It is dropped from the heat radiation tube 15 and refluxed to the refrigerant tank 3.

B) A case where an airtight leak occurs in the boiling cooling device 1. In this case, the refrigerant vapor boiling due to the heat of the heating element 2 leaks to the outside, so that the heat transfer by the refrigerant becomes impossible. However, the heat transfer from the refrigerant tank 3 to the radiator 4 through the heat transfer unit 5. It can be performed. That is, the heat generated in the heating element 2 is transmitted by heat conduction from the partition wall 7a of the hollow container 7 to the main heat transfer section 5A, and further connected from the main heat transfer section 5A, as indicated by arrows in FIG. 5C and the sub heat transfer portion 5B, and is diffused to substantially the entire area of the core portion 12, and the radiation fins 16
It is released to the outside air.

(Effects of the present embodiment) In the boiling cooling apparatus 1 of the present embodiment, even if airtight leakage occurs in the container (refrigerant tank 3 and radiator 4) in which the refrigerant is sealed, the refrigerant is transmitted through the heat transfer section 5 Tank 3
From the heating element 2 to the radiator 4 (heat conduction). As a result, even when the heat transfer by the refrigerant becomes impossible, a certain degree of heat dissipation performance can be maintained by the heat conduction by the heat transfer unit 5, and as shown in FIGS.
A rapid rise in temperature of the heating element 2 can be suppressed, and adverse effects on the heating element 2 (semiconductor element) due to the temperature rise can be prevented. The heat dissipation performance due to this heat conduction is defined by the heat transfer area of the heat transfer section 5, the total heat dissipation area of the heat dissipating fins 16, the speed of cooling air to the heat dissipator 4, and the like. Therefore, if sufficient heat radiation performance can be maintained by heat conduction, as shown in FIG. 10, the surface temperature of the coolant tank 3 (the temperature of the mounting surface of the heating element 2) can be suppressed to the maximum allowable temperature of the heating element 2 or less. is there. Further, even when the heat radiation performance due to heat conduction is low, as shown in FIG.
Can be extended from t1 to t2 (t1 <t2) until the surface temperature exceeds the allowable maximum temperature of the heating element 2.

(Second Embodiment) FIG. 12 is a front view of the boiling cooling device 1. In this embodiment, the partition wall 7a of the hollow container 7 is used.
This is an example in which the heat transfer portions 5 are provided on the upper portion of the partition wall 7b and the upper portion of the partition wall 7b, respectively, and the partition walls 7a and 7b and the heat transfer portion 5 are thermally coupled. In this case, the radiator 4
Since heat can be conducted at a plurality of locations (three locations in FIG. 12), the amount of heat transferred from the refrigerant tank 3 to the radiator 4 by the heat conduction can be increased, and the heat dissipation performance can be improved. Note that the partition wall 7a and the heat transfer section 5 and the partition wall 7b and the heat transfer section 5 are similar to the case where the partition wall 7a and the main heat transfer section 5A are thermally connected as described in the first embodiment. For example, they are joined by brazing or the like (see FIG. 13).

(Third Embodiment) FIG. 14 is a front view (a) and a side view (b) of the boiling cooling device 1. This embodiment is an example in which the heat transfer unit 5 is provided integrally with the hollow container 7 of the refrigerant tank.
As described in the first embodiment, the partition wall 7c provided in the hollow container 7 is extended by extruding the hollow container 7, and as shown in FIG. And can be formed integrally. in this case,
Since there is no joint between the heat transfer section 5 and the partition wall 7c, the heat transfer section 5 and the partition wall are compared with a case where the heat transfer section 5 is formed separately from the partition wall 7c and both are joined. 7c can be reduced, and the heat radiation performance can be improved accordingly. The heat transfer portion 5 may be formed integrally with the partition wall 7a or the partition wall 7b instead of the partition wall 7c.

[Brief description of the drawings]

FIG. 1 is a front view (a) and a side view (b) of a boiling cooling device (first embodiment).

FIG. 2 is a top view (a) and a side view (b) of a hollow container.

FIG. 3 is a drawing showing a shape of an end tank.

FIG. 4 is a view showing a shape of a core plate of an upper tank.

FIG. 5 is a drawing showing a shape of a tank plate of an upper tank.

FIG. 6 is a view showing a shape of a core plate of a lower tank.

FIG. 7 is a view showing a shape of a tank plate of a lower tank.

FIG. 8 is a cross-sectional view showing a joining state between the partition wall and the heat transfer section.

FIG. 9 is a partial sectional view of a core part.

FIG. 10 is a graph showing the effect of the present embodiment.

FIG. 11 is a graph showing the effect of the present embodiment.

FIG. 12 is a front view of a boiling cooling device (second embodiment).

FIG. 13 is a sectional view showing a joining state between a partition wall and a heat transfer section (second embodiment).

FIG. 14 is a front view (a) and a side view (b) of a boiling cooling device.
(Third Example)

FIG. 15 is a sectional view showing an integrated structure of a partition wall and a heat transfer section (third embodiment).

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 boiling cooling device 2 heating element 3 refrigerant tank 4 radiator 5 heat transfer section 5A main heat transfer section (heat transfer section) 5B sub-heat transfer section (heat transfer section) 5C connecting section (heat transfer section) 7 hollow container (extrusion) Material)

Claims (3)

[Claims] A heating element is mounted on the surface of the cooling tank and stores therein a liquid refrigerant. A refrigerant vapor boiled by receiving heat from the heating element in the cooling tank is condensed and liquefied by heat exchange with an external fluid. A cooling device that cools the heating element by heat transport by repeated boiling and condensation of a refrigerant, wherein the refrigerant tank and the radiator are thermally coupled to each other, and heat conduction is performed by heat conduction. A boiling cooling device comprising a heat transfer unit capable of transferring heat from the refrigerant tank to the radiator. 2. The boiling cooling device according to claim 1, wherein the heat transfer section is capable of transferring heat from the refrigerant tank to substantially the entire radiator. 3. The refrigerant tank is formed by using an extruded extruded material, and the heat transfer section is provided by extending a part of the extruded material to the radiator. Claim 1 or 2
The boiling cooling device described in 1.