JP3501911B2 - Boiling cooling device - Google Patents

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 or an electric device.

[0002]

2. Description of the Related Art Conventionally, a boiling cooling device for cooling heat generated by a heating element is known. Among them, JP-A-56
As in the boiling cooling device disclosed in Japanese Patent Publication No. 147457, a flooding (a phenomenon in which they collide with each other) between a vapor refrigerant that is boiled and vaporized in a refrigerant tank and rises, and a liquefied refrigerant that is cooled by a radiator and returns to the refrigerant tank. There is known a boiling cooling device that prevents the above and efficiently performs heat exchange.

That is, the boiling cooling device disclosed in Japanese Patent Laid-Open No. 56-147457 is arranged in a refrigerant tank for containing a refrigerant which is boiled and vaporized by the heat generated by a heating element, and is arranged above the refrigerant tank so as to communicate with the refrigerant tank. An inflow side communication section, a plurality of refrigerant passages that are communicated with the inflow side communication section and are arranged at an angle with respect to the horizontal, and an outflow side communication section that returns the refrigerant condensed and liquefied in the refrigerant path to the refrigerant tank. , (The inflow side communication part, the refrigerant passage, and the outflow side communication part constitute a radiator).

In such a boil cooling device, the refrigerant that has absorbed heat in the refrigerant tank is boiled and vaporized to pass through the inflow side communicating portion to pass through the refrigerant passage to transfer the heat. Also generally,
As a method for improving the heat dissipation characteristics by increasing the internal surface area and improving the heat absorption efficiency, it is known to dispose inner fins in the refrigerant passage of the radiator of the boiling cooling device. In the boiling cooling device disclosed in Japanese Patent Laid-Open No. 56-147457, it is conceivable to dispose inner fins in the refrigerant passage to improve the heat absorption efficiency.

[0005]

However, when the inner fins are arranged to increase the internal surface area of the refrigerant passage, a plurality of small passages partitioned by the inner fins are formed inside the refrigerant passage. FIG. 10A is a reference diagram for explaining this situation. In this case, FIG.
As shown in (b) , the refrigerant sequentially condensed in the refrigerant passages flows out to the outflow side communication portion along the bottom surface 398 of each small passage. The refrigerant condensed here has a temperature lower than that of the vapor refrigerant, and since the condensed refrigerant covers the bottom surface 398, the vapor refrigerant flowing through each small passage is the upper surface 395 and the side surface 3 of the small passage.
The heat can be efficiently transferred to 96, 397, but almost no heat can be transferred to the bottom surface 398. Therefore, there is a problem that the vapor refrigerant cannot efficiently transfer heat to the refrigerant passage. As a result, there arises a problem that the heat radiation performance is deteriorated.

[0006] Therefore, an object of the present invention is to obtain a boiling cooling device having a novel structure and preventing deterioration of heat radiation performance. Another object of the present invention is to obtain a boiling cooling device that prevents the heat dissipation area from being reduced by the refrigerant condensed in the refrigerant passage. Further, the object of the present invention is to
In a boiling cooling device having a radiator in which a refrigerant passage is arranged to be inclined with respect to the horizontal, it is possible to obtain a boiling cooling device that prevents the refrigerant from being easily clogged in the refrigerant passage.

[0007]

The present invention has the following features to attain the object mentioned above. (Claim 1) A refrigerant tank in which a refrigerant vaporized by receiving heat from a heating element is housed, and a radiator provided in communication with the refrigerant tank for condensing and liquefying the refrigerant vaporized in the refrigerant tank. The radiator has an inflow side communication section arranged on the inflow side of the refrigerant, an outflow side communication section arranged on the outflow side of the refrigerant, the inflow side communication section and the outflow side. A refrigerant passage communicating with the communication portion is provided, and the refrigerant passage has an inner bottom surface inclined downward from the inflow side communication portion toward the outflow side communication portion, and the refrigerant vaporized in the refrigerant tank is Condensation fins that condense and liquefy the vaporized refrigerant by condensing and liquefying the refrigerant flowing from the inflow side communication portion to the refrigerant tank from the outflow side communication portion are arranged. ,
The condensing fin is extended in the refrigerant moving direction while being formed in a wave shape in which a wave advances in a vertical direction orthogonal to the refrigerant moving direction of the refrigerant passage, and the condensing fin causes the inside of the refrigerant passage to extend in the longitudinal direction of the refrigerant passage. The condensing fins are provided with a plurality of slits that divide the condensed and liquefied refrigerant to the lower part in the refrigerant passage.

As described above, the condensing fin is provided with a plurality of slits and causes the condensed and liquefied refrigerant to drop to the lower part in the refrigerant passage (42). A region in which the condensed and liquefied refrigerant flows can be formed in the lower portion of the refrigerant passage (42), and an upper portion of the region can be a region in which the vapor-phase refrigerant flows. It is possible to prevent the bottom surface of the small passage formed of the condensation fins from being covered with the condensed refrigerant. As a result, it is possible to prevent the heat dissipation area where the vapor refrigerant can transfer heat from decreasing, and prevent the heat dissipation performance from decreasing. Further , the refrigerant passage (42) is configured so that the refrigerant flows from the inflow side passage portion to the refrigerant passage , condenses and liquefies and flows back to the refrigerant tank from the outflow communication portion.
Since it is formed so as to incline from the 4) side toward the outflow side communication section (45) side, the refrigerant can smoothly flow in the refrigerant passage. In addition, the condensing fins are arranged in a vertical direction that is orthogonal to the moving direction of the refrigerant in the refrigerant passage.
The condensate flowing in the refrigerant passage easily flows from the inflow-side communication portion to the outflow-side communication portion because it is formed in a corrugated shape in which the wave travels and extends in the refrigerant movement direction. Therefore, the amount of condensed liquid accumulated in the refrigerant passage is reduced, and the refrigerant can be condensed efficiently.

(Claim 2) In Claim 2, the refrigerant tank has therein a plurality of vapor passages through which vaporized refrigerant flows and a condensate passage through which condensate condensed and liquefied by a radiator flows down. The inflow side communication portion is formed at an upper end of the vapor passage, the outflow side communication passage is formed at an upper end of the condensate passage, and the refrigerant passage is stacked in parallel with the refrigerant tank. While being formed so as to be inclined downward from the inflow side communication portion toward the outflow side communication furnace, a single plate-shaped member is bent in a wave shape in each of the refrigerant passages, and the outer surface of each uneven portion is formed. The condensing fins that divide the inside of the refrigerant passage into a plurality of small passages by being joined to the inner wall of the refrigerant passage are arranged, and the condensing fins include a plurality of flat plate portions between joint portions with the refrigerant passage. The slit of To collect. With this configuration, the vaporized refrigerant easily flows from the steam passage toward the inflow communication passage,
It is possible to achieve an effect that the condensed liquid refrigerant can be easily returned to the condenser passage.

(Claim 3) In claim 3, the refrigerant passage (42) is connected to the inflow side.
From the communication part (44) side to the outflow side communication part (45) side
The direction of refrigerant movement is formed, and the slits
Formed on the fins at different positions in the direction of movement of the refrigerant
It is characterized by being done. Pass through each slit
The amount of condensate that collects in the cooling medium passage decreases. This conclusion
As a result, the condensate can pass through each slit smoothly.
Therefore, the condensed liquid is less likely to collect in the refrigerant passage. Result, steam
The vapor refrigerant can be condensed efficiently and the heat dissipation performance is low.
Can prevent lowering.

(Claim 4) In Claim 4, the radiator (4) has a bonding portion.
Laminate multiple plate-shaped members at the laminating section.
The bonded portion is a plate-shaped portion.
It is formed by bending and bending a material. As mentioned above
The radiator (4) is formed by bonding a plurality of plate-shaped members together.
Therefore, the radiator (4) can be easily formed.

[0012]

[0013]

[0014]

[0015]

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the boiling cooling apparatus of the present invention will be described. (First Embodiment) FIG. 1 is a perspective view of a boiling cooling apparatus 1 according to the first embodiment, and FIG. 2 is II 'in FIG.
Sectional view, FIG. 3 is a partial sectional view taken along the line II-II ′ in FIG. 3, and FIG.
I-III 'partial sectional view, FIG. 5 is an explanatory view of the molding plate 40, and FIG. 6 is an IV-IV' sectional view in FIG.

In this embodiment, in order to facilitate returning of the condensed liquid liquefied in the radiator 4, each radiation pipe 39 constituting the radiator 4 is attached in an inclined manner. 1 and 2, the refrigerant tank 3 includes an extruded material 7 formed by extruding an aluminum block material, and an end cap 22 that covers one open end (lower end) of the extruded material 7. Consists of.

The extruded material 7 includes a column portion 3 extending vertically.
A plurality of vapor passages 9 (vapor-phase refrigerant passages), a condensate passage 10 (condensate passage), and a non-operation passage 33, which are partitioned by 0 to 32, are provided. Further, the opening surface of each vapor passage 9 and the opening surface of the condensate passage 10 are provided as an outlet 35 for the vapor refrigerant and an inlet 36 for the condensate, respectively.

The end cap 22 is made of the same aluminum as the extruded material 7 and is covered on the outer peripheral portion of the lower end of the extruded material 7 and joined by integral brazing. However, between the end cap 22 and the lower end surface of the extruded material 7, the vapor passage 9, the condensate passage 10, and the non-operation passage 3 formed in the extruded material 7.
A communication passage 38 that communicates with each other 3 is formed. The end cap 22 is provided with a refrigerant enclosing tube 49, through which the inside of the apparatus 1 is cleaned, refrigerant is injected, and deaeration is performed. For deaeration, after injecting the refrigerant, the whole apparatus 1 is turned upside down and the radiator 4 is put in a warm water tank (where the saturated vapor pressure of the refrigerant is kept at a temperature higher than the atmospheric pressure), and the apparatus 1 This is done by vaporizing the refrigerant inside and expelling the air (the refrigerant gas is heavier than air). After degassing, the end portion of the tube 49 is caulked and sealed by welding or the like, so that the refrigerant is sealed in the device 1.

The radiator 4 is a so-called drone cup type heat exchanger, and is constructed by laminating a plurality of radiator tubes 39 having the same hollow shape as shown in FIG. Radiant pipe 39
Is formed into a hollow body by joining the outer peripheral edge portions of the two molding plates 40 (for example, aluminum plates) shown in FIG.
An inflow-side communication portion 44 and an outflow-side communication portion 45 each having a small diameter opening 41 are provided at both ends. This heat dissipation pipe 39
Is a flat refrigerant passage 42 between the communication portions 44 and 45. In the coolant passage 42, an inner fin 391 formed by corrugating a thin aluminum plate as shown in FIG.
(Condensing fin) is inserted. 5A is a side view of the molding plate 40, and FIG. 5B is a front view of the molding plate 40.

The connecting pipe 51 is constructed by bonding two plates 50 together, and is covered on the outer peripheral portion of the upper end of the refrigerant tank 3 as shown in FIG. 3, so that the radiator 4 and the refrigerant tank 3 are communicated with each other. . As shown in FIG. 2, the inside of the connecting pipe 51 is provided with a separator 52 (refrigerant flow control plate) so that an outlet 35 of the refrigerant tank 3 can be provided.
It is divided into an inflow chamber 511 communicating with (see FIG. 2) and an outflow chamber 512 communicating with the inflow port 36. A plurality of connecting pipe inner fins 53 are inserted into the inflow chamber 511 of the connecting pipe 51.

7A is an enlarged view of the inner fin 391 in FIG. 6, FIG. 7B is a side view of FIG. 6A, and FIG. 8 is a perspective view of the inner fin 391 shown in FIG. . As shown in FIG. 2, FIG. 7, and FIG.
91 is provided with a plurality of slits 392 (openings) for lowering the condensed and liquefied refrigerant to the lower part in the refrigerant passage 42.
In other words, in the refrigerant passage 42, the vapor-phase refrigerant passage 393 composed of a plurality of small passages through which the vapor-phase refrigerant flows and the condensate passage 394 through which the condensed and liquefied refrigerant flows are formed, and the vapor-phase refrigerant passage 393 is formed. An inner fin 391 for condensing and liquefying the vaporized refrigerant is provided in the inner fin 391.
In addition, a plurality of slits 392 for dropping the condensed and liquefied refrigerant into the condensed liquid passage 394 are formed. The inner fins 391 are provided on the upper passage 395 and the side face 3 of each small passage.
9 6 and the bottom surface 398, it can be said that the passages defined by the configured side 397 on the inner surface of the forming plate 40. In addition, in the present embodiment, the slits 392 are formed in the inner fins 391 at different positions in the refrigerant moving direction.

As shown in FIG. 4, the radiating pipes 39 are stacked on one side of the connecting pipe 51 and communicate with each other through the small-diameter openings 41. The connecting pipe 51 and the heat radiating pipe 39 are mutually connected through a small diameter opening 41 formed in the plate 50 of the connecting pipe 51 (a plate on the heat radiating pipe 39 side) and a small diameter opening 41 formed in the heat radiating pipe 39. Is in communication with. However, the respective heat radiation pipes 39 are attached in an inclined state so that the inflow side communication portion 44 is higher than the outflow side communication portion 45 with respect to the connection pipe 51 (FIG. 2).
reference). The rib 50b provided on the plate 50
Function as a rib for reinforcing the joint surface with the heat dissipation pipe 39.

Next, the operation of the first embodiment will be described. As shown by the circulation of the refrigerant in FIG. 1, the refrigerant generated by the heat generated from the IGBT module 2 and being boiled, becomes bubbles and rises in the respective vapor passages 9, and flows from the outlet 35 of the refrigerant tank 3 to the connecting pipe. After flowing into the inflow chamber 51, the inflow chamber further flows into the inflow side communication portion 44 of each heat radiation pipe 39 and is distributed to the refrigerant passage 42 of each heat radiation pipe 39. Here, in FIG. 1, it is simplified and described by one line. The vapor refrigerant flowing in each refrigerant passage 42 is blown by the cooling fan 5 (not shown) and is condensed on the inner wall surface of the refrigerant passage 42 and the surface of the inner fin 391 which are at a low temperature to release condensation latent heat to form droplets. Become.

The condensed and liquefied refrigerant is the inner fin 391.
Although it moves to the outflow side communication part 45 side along the surface of the, it drops in the lower part from the slit 392 in the middle (see FIG. 7),
Move to the lower inner fin 391. Since a plurality of slits 392 are formed in the present embodiment, the above dropping is sequentially performed and reaches the bottom surface of the refrigerant passage 42. In other words,
The refrigerant condensed and liquefied in each small passage of the vapor-phase refrigerant passage 393 in the refrigerant passage 42 drops through the slit 392 to the lower small passage, and further to the condensed liquid passage 394. Finally, it flows into the outflow side communication portion 45 of each heat radiation pipe 39 while flowing through the bottom surface of the refrigerant passage 42.

After that, the outlet side communicating portion 45 to the connecting pipe 51
The condensate that has flowed out to the outflow chamber of the refrigerant flows into the condensate passage 10 from the inflow port 36 of the refrigerant tank 3, flows down the condensate passage 10, and then passes through the communication passage 38 in the end cap again to each vapor passage 9 Is supplied to. (Effect of the First Embodiment) As shown in FIG. 7A, the inner fin 391 has a plurality of slits 392, and causes the condensed and liquefied refrigerant to drop to the lower part in the refrigerant passage 42.
A region in which the condensed and liquefied coolant flows can be formed on the lower side in the coolant passage 42, and a region above the region can be a region in which the vapor-phase coolant flows. As a result, it is possible to prevent the bottom surface of the small passage formed by each condensing fin in the refrigerant passage 42 from being covered with the condensed refrigerant. That is, in FIG. 7B, the vapor refrigerant does not only heat the bottom surface 398 as well as the top surface 395 and the side surfaces 396 and 397 among the small passages formed by the top surface 395, the side surfaces 396 and 397, and the bottom surface 398. Can be told. As a result, it is possible to prevent the heat dissipation area where the vapor refrigerant can transfer heat from decreasing, and prevent the heat dissipation performance from decreasing.

The slit 392 is formed by the inner fin 39.
Since they are formed at different positions in the refrigerant moving direction in No. 1, the amount of the condensed liquid accumulated in the refrigerant passage is reduced, and the vapor refrigerant can be condensed efficiently. (Other effects of the first embodiment) (1) In the present embodiment, since the small-diameter opening 41 of the small-diameter portion is provided in the inlet communication portion, the infiltration of the liquid-phase refrigerant into the refrigerant passage 42 is achieved. Can be suppressed. As a result, the refrigerant passage 42
It is possible to transfer heat by condensing heat transfer inside, so that it is possible to prevent deterioration of heat dissipation performance. Further, by providing the small-diameter openings, it is possible to prevent uneven distribution of the refrigerant flowing into the communication passages 42, and also to distribute the refrigerant evenly to the communication passages 42. Can be prevented.

(2) Further, by sloping the heat radiating pipe 39 with respect to the connecting pipe 51, the liquefied condensate flows through the refrigerant passage 42 of the heat radiating pipe 39 from the inflow side communicating portion 44 to the outflow side communicating portion 45. It becomes easier to flow. As a result, the amount of the condensed liquid accumulated on the bottom surface of the refrigerant passage 42 is reduced, and the vapor refrigerant can be condensed efficiently. As a result, the required amount of refrigerant can be reduced and the cost can be reduced.

(3) Since the steam passage 9 is divided into a plurality of passages by the supporting column 31, the flow of the steam refrigerant flowing through the steam passage 9 can be rectified, and the supporting column 31 can be formed.
As a result, the effective boiling area is increased and the heat dissipation performance can be improved.
Further, the strength of the refrigerant tank 3 against positive and negative pressures is improved, and deformation of the mounting surface on which the IGBT module 2 is mounted is prevented.

(4) Since the radiator can be constructed by laminating a plurality of radiating pipes of the same hollow shape on the connecting member connected to the refrigerant tank, the number of attached heating elements is increased and the total amount of heat generated is increased. Even if it increases, the capacity of the radiator can be easily changed. That is, since the capacity of the radiator can be easily increased by sequentially stacking the same hollow radiator tubes, a radiator having a capacity corresponding to the total heat generation amount can be provided at low cost.

(5) Inside the refrigerant tank 3, a lower communication passage 38 for connecting the vapor passage and the condensed liquid passage to each other at the lower portion in the refrigerant tank.
Therefore, the cooled refrigerant is always supplied to the vapor passage from the condensate passage. Therefore, flooding (mutual interference between the vapor refrigerant and the condensed liquid refrigerant) in the refrigerant tank can be prevented. (6) Since the heat radiating pipe 39 is connected to the coolant tank 3 via the connecting member 51, the mounting direction and position of the heat radiating pipe 39 can be appropriately changed depending on the shape of the connecting member, and the degree of freedom in design is improved. To do. This also enables downsizing.

(7) Since the bottom surface is inclined downward from the inflow side communication portion 44 toward the outflow side communication portion 45, the condensate flowing through the refrigerant passage moves from the inflow side communication portion to the outflow side communication portion. It becomes easy to flow. Therefore, the amount of the condensed liquid accumulated on the bottom surface of the refrigerant passage is reduced, and the vapor refrigerant can be condensed efficiently. (8) Since the refrigerant tank 3 is made of an extruded material that is extruded, it is possible to easily cope with a change in the number of IBGTs attached, which leads to an improvement in productivity.

(9) Since the partition wall is provided integrally with the extruded material and divides the inside of the refrigerant chamber, the vapor passage 9 and the condensate passage 10 can be easily constructed. (10) Since the plurality of steam passages 9 can be communicated with the steam outlet 35 only by removing the upper portion of the column portion 31 provided on the extruded material, it is possible to cool the refrigerant at low cost without adding special parts. You can control the circulation.

(11) By removing the lower part of the pillar provided on the extruded material and joining the closing member to the lower end surface of the extruded material, the vapor passage and the condensate passage are communicated with each other in the lower portion of the refrigerant chamber. can do. Therefore, the closing member can be formed in a simple shape (for example, a simple flat plate), which facilitates the production of the closing member. (12) In the refrigerant tank 3, a refrigerant chamber can be provided for each heating element, corresponding to the case where a plurality of heating elements are attached. In this case, since the refrigerant is circulated evenly in the entire refrigerant tank by communicating the refrigerant chambers, it is possible to prevent the heat dissipation performance from being deteriorated due to the uneven distribution of the condensed refrigerant.

(13) Since the refrigerant tank has a flat shape, the amount of refrigerant used can be reduced, so that the cost can be kept low even when an expensive fluorocarbon refrigerant is used. (14) The vapor passage and the condensate passage may be configured by the refrigerant flow control plate arranged in the refrigerant chamber. In this case, in addition to the effect of preventing flooding, it is expected that the refrigerant flow control plate is arranged in contact with the inner wall surface of the refrigerant chamber to improve the rigidity of the refrigerant chamber and the heat dissipation performance by increasing the heat dissipation area of the refrigerant chamber. it can.

(15) Not only the refrigerant tank but also the radiator are constructed by using the extruded material extruded integrally with the refrigerant tank, so that the cost of the radiator can be reduced as compared with the conventional apparatus. Since the process of assembling the radiator and the coolant tank is not required, the cost of the entire device can be reduced. (16) The radiator 4 is formed by bonding a plurality of plate-shaped members each having a bonded portion at the bonded portion, and the bonded portion is formed by bending and bending the plate-shaped member. Therefore, the radiator can be easily formed.

(17) Further, the plurality of slits 392 cause the condensed and liquefied refrigerant to drop to the lower part in the refrigerant passage 42. Since the condensed liquid passage 394 through which the condensed and liquefied refrigerant flows is formed on the lower side in the refrigerant passage 42, and the gas phase refrigerant passage 393 through which the vapor phase refrigerant flows can be formed above the condensed and liquefied passage. It is possible to prevent the refrigerant from being easily clogged in the passage 42. As a result, it is possible to prevent a decrease in the minimum flow passage cross-sectional area, which is the minimum cross-sectional area through which the gas-phase refrigerant can pass through in the gas-phase refrigerant passage 393, and prevent a decrease in heat dissipation performance.

Incidentally, in FIG. 7, the slit 392 is
Are formed at different positions on the inner fin 391,
In the present invention, the slits 392 may be formed at substantially the same position as shown in FIG. This facilitates formation of the slit 392 .

[Brief description of drawings]

FIG. 1 is a perspective view of a boiling cooling device according to a first embodiment.

2 is a cross-sectional view taken along the line I-I 'in FIG.

FIG. 3 is a partial cross-sectional view taken along the line II-II ′ in FIG.

FIG. 4 is a partial cross-sectional view taken along the line III-III ′ of FIG.

5A is a side view of the forming plate, and FIG. 5B is a plan view of the forming plate.

6 is a cross-sectional view taken along the line IV-IV 'in FIG.

7 (a) is an enlarged view of the inner fin in FIG. 6,
(B) is a side view of (a).

8 is a perspective view of the inner fin shown in FIG. 7. FIG.

FIG. 9 is a diagram showing another configuration of the inner fin.

10A and 10B are references for explaining a problem.
It is a figure.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masahiko Suzuki               1-1, Showa-cho, Kariya city, Aichi stocks               Company DENSO                (56) Reference JP-A-6-53376 (JP, A)                 JP-A-56-147457 (JP, A)

Claims (4)

(57) [Claims] 1. A refrigerant tank in which a refrigerant vaporized by receiving heat from a heating element is contained, and a radiator provided in communication with the refrigerant tank for condensing and liquefying the refrigerant vaporized in the refrigerant tank. The radiator has an inflow side communication section arranged on the inflow side of the refrigerant, an outflow side communication section arranged on the outflow side of the refrigerant, and the inflow side communication section and the outflow side. There is a refrigerant passage communicating with the communication portion, the refrigerant passage, the inner bottom surface is inclined downward from the inflow side communication portion toward the outflow side communication portion, the refrigerant vaporized in the refrigerant tank, Condensing fins for condensing and liquefying the vaporized refrigerant are arranged in the refrigerant passage from the inflow side communication section to condense and liquefy, and return to the refrigerant tank from the outflow side communication section. , The condensing fin is orthogonal to the direction of movement of the refrigerant in the refrigerant passage. That vertically extends in the coolant transfer direction while being formed into a wave shape the wave proceeds, said refrigerant passage by the condensed fins are partitioned and formed into a plurality of small passages extending in the longitudinal direction of the refrigerant passage, the condensing fins Is equipped with a plurality of slits for lowering the condensed and liquefied refrigerant to the lower part in the refrigerant passage. 2. The refrigerant tank has therein a plurality of vapor passages through which vaporized refrigerant flows, and a condensate passage through which a condensate condensed and liquefied by a radiator flows down, and the inflow side communication portion is The vapor passage is formed at an upper end of the vapor passage, the outflow communication passage is formed at an upper end of the condensate passage, and the refrigerant passage is stacked in parallel with the refrigerant tank from the inflow passage. It is formed so as to incline downward toward the outflow side communication passage, and one plate-shaped member is bent in a wave shape in each of the refrigerant passages, and the outer surface of each uneven portion is joined to the refrigerant passage inner wall. The condensing fins that divide the inside of the refrigerant passage into a plurality of small passages are thereby arranged, and the condensing fins have a plurality of slits formed in the flat plate portion between the joint portions with the refrigerant passages. A boiling point according to claim 1, wherein Soaring cooler. 3. The refrigerant passage has a refrigerant movement direction from the inflow side communication portion side toward the outflow side communication portion side, and in the adjacent upper and lower small passages, the slit is formed in the condensing fin. The evaporative cooling device according to claim 1, wherein the evaporative cooling device is formed at different positions in the moving direction of the refrigerant. 4. The radiator is formed by bonding a plurality of plate-shaped members having a bonded portion at the bonded portion, and the bonded portion bends and raises the plate-shaped member. The boiling cooling device according to any one of claims 1 to 3, which is formed by the following method.