HEAT DISSIPATION DEVICE

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 113210376, filed on September 25, 2024. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND

Technical Field

The disclosure relates to a heat dissipation device, and in particular relates to a heat dissipation device applied to a heat source on a circuit board.

Description of Related Art

Generally, the thermal diffusivity of fanless heat sinks currently available in the market is often limited by the structure, resulting in suboptimal performance. Furthermore, while installing pumps to enhance convection circulation may improve thermal diffusivity, such measures increase the power consumption of the heat sink and adversely affect its operational lifespan. Therefore, how to achieve a good heat dissipation effect without increasing the power consumption of the heat sink and maintaining the lifespan of the heat sink is a topic that professionals in this field are dedicated to exploring.

SUMMARY

A heat dissipation device which achieves a good heat dissipation effect is provided in the disclosure.

A heat dissipation device of the disclosure is adapted to dissipate heat from a heat source, in which the heat dissipation device includes a casing, a heat conducting base, a heat conducting block, multiple heat dissipation pipes, at least one first heat dissipation fins assembly, and a heat dissipation medium. The heat source is disposed inside the casing. The heat conducting base is disposed inside the casing, in which the heat conducting base is thermally coupled to the heat source and has a cavity and a side portion surrounding the cavity. The heat conducting block is disposed inside the cavity and is thermally coupled to the heat conducting base. The heat dissipation pipes are inserted into the casing. Each of the heat dissipation pipes has a first end and a second end opposite to the first end. The first end of each of the heat dissipation pipes is inserted into the side portion and is interconnected with the cavity. The second end of each of the heat dissipation pipes is interconnected to the cavity. The at least one first heat dissipation fins assembly is disposed on the casing and partially covers the cavity. The heat dissipation pipes are thermally coupled to the at least one first heat dissipation fins assembly. The heat dissipation medium is stored inside the cavity and immerses at least a portion of the heat conducting block.

Based on the above, in the heat dissipation device of the disclosure, the heat generated by the heat source is transmitted to the heat dissipation medium through the heat conducting base and the heat conducting block. After the heat dissipation medium absorbs a certain amount of heat, the heat dissipation medium undergoes a phase change from liquid to gas. The gaseous heat dissipation medium flows upward from the top opening through the second end into the heat dissipation pipes due to the pressure difference and the temperature difference, and performs heat exchange with the first heat dissipation fins assembly in the process of flowing through the heat dissipation pipes. Finally, the heat dissipation medium flows out of the heat dissipation pipes from the first end and flows into the cavity, thus completing the cycle. Accordingly, the heat dissipation device of the disclosure may cycle the heat dissipation medium without an additional pump to effectively transfer the heat generated by the heat source to the outside, thereby achieving a good heat dissipation effect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A to FIG. 1C are schematic diagrams of a heat dissipation device of an embodiment of the disclosure at different viewing angles.

FIG. 2 is an exploded diagram of the heat dissipation device of FIG. 1A.

FIG. 3 is a cross-sectional diagram of the heat dissipation device of FIG. 1B along line A-A.

FIG. 4 is a cross-sectional diagram of the heat dissipation device of FIG. 1B along line B-B.

FIG. 5 is a cross-sectional diagram of the heat dissipation device of FIG. 1C along line C-C.

FIG. 6A to FIG. 6C are schematic diagrams of the heat conducting block of FIG. 3 at different viewing angles.

FIG. 7 is a cross-sectional diagram of the heat conducting block of FIG. 6C along line D-D.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

FIG. 1A to FIG. 1C are schematic diagrams of a heat dissipation device of an embodiment of the disclosure at different viewing angles. FIG. 2 is an exploded diagram of the heat dissipation device of FIG. 1A. FIG. 3 is a cross-sectional diagram of the heat dissipation device of FIG. 1B along line A-A. Referring to FIG. 1A to FIG. 3, the heat dissipation device 100 of this embodiment is adapted to dissipate heat from a heat source 10 disposed on a circuit board 20 as shown in FIG. 3. The heat source 10 is, for example, a central processing unit (CPU) or a graphics processing unit (GPU), but not limited thereto. The structure of the heat dissipation device 100 is described in detail below.

FIG. 4 is a cross-sectional diagram of the heat dissipation device of FIG. 1B along line B-B. Referring to FIG. 1A, FIG. 2, FIG. 3 and FIG. 4, the heat dissipation device 100 includes a casing 110, a heat conducting base 120, a heat conducting block 130, multiple heat dissipation pipes 140, at least one first heat dissipation fins assembly 150 (two are shown), and a heat dissipation medium 160. The heat source 10 is disposed inside the casing 110. The heat conducting base 120 is disposed inside the casing 110. The heat conducting base 120 is thermally coupled to the heat source 10 and has a cavity 121 and a side portion 123 surrounding the cavity 121. As shown in FIG. 4, the heat conducting block 130 is disposed inside the cavity 121 and is thermally coupled to the heat conducting base 120. As shown in FIG. 3, multiple heat dissipation pipes 140 are inserted into the casing 110. As shown in FIG. 3, each of the heat dissipation pipes 140 has a first end 141 and a second end 143 opposite to the first end 141. The first end 141 of each of the heat dissipation pipes 140 is inserted into the side portion 123 and is interconnected with the cavity 121. The second end 143 of each of the heat dissipation pipes 140 is interconnected to a top opening 1215 of the cavity 121. The at least one first heat dissipation fins assembly 150 is disposed on the casing 110 and partially covers the cavity 121. The heat dissipation pipes 140 are thermally coupled to the at least one first heat dissipation fins assembly 150. The heat dissipation medium 160 is stored inside the cavity 121 and immerses at least a portion of the heat conducting block 130.

As described above, in the heat dissipation device 100 of this embodiment, the heat generated by the heat source 10 is transmitted to the heat dissipation medium 160 through the heat conducting base 120 and the heat conducting block 130. After the heat dissipation medium 160 absorbs a certain amount of heat, the heat dissipation medium 160 undergoes a phase change from liquid to gas. The gaseous heat dissipation medium 160 flows upward from the top opening 1215 through the second end 143 into the heat dissipation pipes 140 due to the pressure difference and the temperature difference, and performs heat exchange with the first heat dissipation fins assembly 150 in the process of flowing through the heat dissipation pipes 140. Finally, the heat dissipation medium 160 flows out of the heat dissipation pipes 140 from the first end 141 and flows into the cavity 121, thus completing the cycle. Accordingly, the heat dissipation device 100 of the disclosure may cycle the heat dissipation medium 160 without an additional pump to effectively transfer the heat generated by the heat source 10 to the outside, thereby achieving a good heat dissipation effect.

In this embodiment, the circuit board 20 is disposed inside the casing 110, and the heat source 10 is located between the heat conducting base 120 and the circuit board 20. In this embodiment, the first heat dissipation fins assembly 150 includes multiple first fins 151, and the number of the first fins 151 of each first heat dissipation fins assembly 150 is twelve. Each of the first fins 151 extends along the axial direction X and the axial direction Z (i.e., each of the first fins 151 is parallel to the XZ plane), and these first fins 151 are disposed at intervals along the axial direction Y. However, the disclosure does not limit the setting direction and number of the first fins 151. In this embodiment, the heat dissipation medium 160 is, for example, water, but the disclosure is not limited thereto.

The distribution state and position of the heat dissipation medium 160 in the cavity 121 are described in detail below.

FIG. 5 is a cross-sectional diagram of the heat dissipation device of FIG. 1C along line C-C. In order to clearly illustrate the heat conducting block 130 of FIG. 5, the number of second heat dissipation fins assemblies 132 and fourth heat dissipation fins assemblies 138 of FIG. 5 is schematically illustrated. Referring to FIG. 3 and FIG. 5, the heat conducting base 120 includes the top opening 1215 interconnected with the cavity 121. A top space 1211 is formed between the heat conducting block 130 and the top opening 1215. A lateral space 1213 is formed between the heat conducting block 130 and the side portion 123. The top space 1211 is interconnected with the top opening 1215 as shown in FIG. 3, and the top space 1211 and the lateral space 1213 are interconnected to each other as shown in FIG. 5. In this embodiment, the liquid heat dissipation medium 160 is stored in the lower region of the lateral space 1213, and is depicted with horizontal short lines in FIG. 3 and FIG. 5. The gaseous heat dissipation medium 160 is stored in the upper region of the lateral space 1213 and in the top space 1211. In more detail, the gaseous heat dissipation medium 160 is located above a liquid surface 161 (see FIG. 3) of the liquid heat dissipation medium 160.

Referring to FIG. 3, in order to achieve a good heat dissipation effect for the heat dissipation device 100 of this embodiment, the first end 141 of each of the heat dissipation pipes 140 of this embodiment includes a connecting opening 1411. As shown in FIG. 3, a distance D1 from a center 1411a of the connecting opening 1411 to a bottom portion 1217 of the cavity 121 is less than a height H1 from the liquid surface 161 of the liquid heat dissipation medium 160 stored in the lateral space 1213 to the bottom portion 1217. In other embodiments, the distance D1 from the center 1411a to the bottom portion 1217 may also be equal to the height H1 from the liquid surface 161 to the bottom portion 1217, and the disclosure is not limited thereto. The heat dissipation device 100 of this embodiment, as a result of the height H1 of the liquid heat dissipation medium 160 exceeding the distance D1 from the center 1411a to the bottom portion 1217, may enhance the latent heat of the heat dissipation medium 160 available for heat absorption, thereby further improving the heat dissipation effect of the heat dissipation device 100.

The structure of the heat conducting block 130 is described in detail below.

FIG. 6A to FIG. 6C are schematic diagrams of the heat conducting block of FIG. 3 at different viewing angles. Referring to FIG. 3 and FIG. 6A, the heat conducting block 130 has a top surface 131 facing the top opening 1215 as shown in FIG. 3. The top surface 131 has at least one recess 1311, and the recess 1311 is interconnected to the top space 1211 as shown in FIG. 3. As shown in FIG. 6A, the heat conducting block 130 is provided with at least one second heat dissipation fins assembly 132 (two are shown) on the top surface 131, and the at least one second heat dissipation fins assembly 132 is located at one side of the recess 1311. In this embodiment, the number of recesses 1311 is three, the second heat dissipation fins assembly 132 on the left is located on the left side of the leftmost recess 1311, and the second heat dissipation fins assembly 132 on the right is located on the right side of the rightmost recess 1311, but the number of the recesses 1311, the number of the second heat dissipation fins assemblies 132 and the setting positions are not limited to the above.

Specifically, referring to FIG. 6A, the at least one second heat dissipation fins assembly 132 includes multiple second fins 1321 disposed in parallel, and a first slit S1 between two adjacent second fins 1321 extends from the lateral space 1213 to the recess 1311 as shown in FIG. 5. Accordingly, the gaseous heat dissipation medium 160 located in the lateral space 1213 may move along the first slit S1 to the recess 1311, and then move to the top space 1211 as shown in FIG. 3. In this embodiment, each of the second fins 1321 is perpendicular to the top surface 131 and extends along the axial direction Y (i.e., each of the second fins 1321 is parallel to the YZ plane). These second fins 1321 are arranged at intervals along the axial direction X, and the first slit S1 is parallel to the axial direction Y, but not limited thereto.

Referring to FIG. 6A to FIG. 6C, the heat conducting block 130 further has a first side surface 133 facing the lateral space 1213 as shown in FIG. 5, a second side surface 134 opposite to the first side surface 133, a third side surface 135, and a fourth side surface 136 opposite to the third side surface 135. As shown in FIG. 5, the lateral space 1213 surrounds the first side surface 133, the second side surface 134, the third side surface 135, and the fourth side surface 136. The heat conducting block 130 is provided with a third heat dissipation fins assembly 137 on at least one of the first side surface 133 and the second side surface 134. In this embodiment, the heat conducting block 130 is provided with a third heat dissipation fins assembly 137 on both the first side surface 133 and the second side surface 134, but the disclosure is not limited thereto.

Specifically, referring to FIG. 6A, the third heat dissipation fins assembly 137 includes multiple third fins 1371 disposed in parallel, and each of the third fins 1371 is perpendicular to the first side surface 133 or the second side surface 134. In addition, as shown in FIG. 6B, the recess 1311 extends from the first side surface 133 toward the second side surface 134 and penetrates the first side surface 133 and the second side surface 134. At least a portion of the third fins 1371 of the third heat dissipation fins assembly 137 extends across one side of the recess 1311. Accordingly, the gaseous heat dissipation medium 160 located in the lateral space 1213 may move to the recess 1311 along a second slit S2 between two of the third fins 1371, and then move to the top space 1211 as shown in FIG. 3. In this embodiment, each of the third fins 1371 extends along the axial direction X and the axial direction Y (i.e., each of the third fins 1371 is parallel to the XY plane). These third fins 1371 are arranged at intervals along the axial direction Z, and the second slit S2 is parallel to the axial direction Y, but not limited thereto.

Referring to FIG. 6A to FIG. 6C, as shown in FIG. 6A, the heat conducting block 130 is further provided with at least one fourth heat dissipation fins assembly 138 (two are shown) on the top surface 131, and the recess 1311 is located between the at least one second heat dissipation fins assembly 132 and the at least one fourth heat dissipation fins assembly 138. Accordingly, at least a portion of the gaseous heat dissipation medium 160 that moves to the recess 1311 through the first slit S1 and the second slit S2 may move to the middle recess 1311 along a third slit S3. In this embodiment, the number of the fourth heat dissipation fins assemblies 138 is not limited thereto. In other embodiments, the number of the fourth heat dissipation fins assemblies 138 may also be, for example, one or three, or the heat conducting block 130 may not have the fourth heat dissipation fins assembly 138. In addition, in this embodiment, the fourth heat dissipation fins assembly 138 is parallel to the second heat dissipation fins assembly 132 and the direction of each of the fourth fins 1381 is the same as the direction of the second fin 1321, and the third slit S3 is parallel to the axial direction Y.

In this embodiment, the spacing between two adjacent second fins 1321, the spacing between two adjacent third fins 1371, and the spacing between two adjacent fourth fins 1381, that is, the width of the first slit S1, the second slit S2, and the third slit S3, respectively, are less than or equal to 0.5 mm, but not limited thereto.

The heat dissipation device 100 of this embodiment, through the arrangement of the second heat dissipation fins assembly 132, the third heat dissipation fins assembly 137, and the fourth heat dissipation fins assembly 138, enables the second heat dissipation fins assembly 132, the third heat dissipation fins assembly 137, and the fourth heat dissipation fins assembly 138 to perform heat exchange with the heat dissipation medium 160, thereby further improving the heat dissipation effect of the heat dissipation device 100.

FIG. 7 is a cross-sectional diagram of the heat conducting block of FIG. 6C along line D-D. Referring to FIG. 6A and FIG. 7, the heat conducting block 130 is provided with at least one tapered hole 139 on at least one of the third side surface 135 and the fourth side surface 136. In this embodiment, six tapered holes 139 are respectively defined in the third side surface 135 and the fourth side surface 136, but the number of the tapered holes 139 is not limited thereto. As shown in FIG. 3, an opening 1391 of the at least one tapered hole 139 faces the first end 141 of the heat dissipation pipes 140. For example, the opening 1391 on the right faces the first end 141 of the heat dissipation pipe 140 of the right side, and the opening 1391 on the left faces the first end 141 of the heat dissipation pipe 140 of the left side.

Referring to FIG. 7, the at least one tapered hole 139 further has a bottom surface 1393 opposite to the opening 1391, and a diameter 1391a of the opening 1391 gradually decreases from the opening 1391 to the bottom surface 1393. The heat dissipation device 100 of this embodiment may increase the return speed of the liquid heat dissipation medium 160 from the heat dissipation pipes 140 by configuring the tapered hole 139 and the gradually decreasing hole diameter 1391a.

Referring to FIG. 6A, a coating layer such as a capillary structure layer is disposed on the surface of the heat conducting block 130 located in the cavity 121 shown in FIG. 3. For example, a capillary structure layer is disposed on the surface of the top surface 131 of the heat conducting block 130, the surface of the first side surface 133, the surface of the second side surface 134, the surface of the third side surface 135, the surface of the fourth side surface 136, the surface of the second heat dissipation fins assembly 132, the surface of the third heat dissipation fins assembly 137, the surface of the fourth heat dissipation fins assembly 138, and the inner wall of the tapered hole 139, but not limited thereto. Accordingly, the heat dissipation device 100 of this embodiment may guide the liquid heat dissipation medium 160 to flow back to the lateral space 1213 of the cavity 121 through the capillary structure layer, and may ensure that the gaseous and liquid heat dissipation medium 160 are separated from each other. In addition, the heat dissipation device 100 may also ensure that the liquid heat dissipation medium 160 may flow along the first slit S1, the second slit S2, and the third slit S3 through the capillary structure layer, so that the heat dissipation medium 160 may perform heat exchange with the second heat dissipation fins assembly 132, the third heat dissipation fins assembly 137 and the fourth heat dissipation fins assembly 138, and flow back to the lateral space 1213.

Referring to FIG. 3, the heat dissipation device 100 of the present embodiment further includes a cover plate 170. The cover plate 170 is disposed on one side of the at least one first heat dissipation fins assembly 150 and closes the top opening 1215 together with the at least one first heat dissipation fins assembly 150. The second end 143 of each of the heat dissipation pipes 140 is inserted into the cover plate 170. The cover plate 170 is aligned with the recess 1311, that is, the recess 1311 is located within the projection range of the cover plate 170. Accordingly, the heat dissipation device 100 of this embodiment closes the top opening 1215 through the cover plate 170 and the first heat dissipation fins assembly 150, thereby preventing the gaseous heat dissipation medium 160 in the cavity 121 from escaping. In addition, the heat dissipation device 100 enables the gaseous heat dissipation medium 160 to move smoothly from the top space 1211 to the second end 143 by aligning the cover plate 170 with the recess 1311. In this embodiment, the cover plate 170 is disposed between two first heat dissipation fins assemblies 150, but the disclosure is not limited thereto.

The heat dissipation mechanism of the heat dissipation device 100 of this embodiment is described in detail below.

When the heat source 10 generates heat, firstly, the heat of the heat source 10 is conducted to the heat conducting block 130 via the heat conducting base 120. Then, the heat is exchanged with the heat dissipation medium 160 through the surface of the heat conducting block 130, the second heat dissipation fins assembly 132, the third heat dissipation fins assembly 137 and the fourth heat dissipation fins assembly 138 as shown in FIG. 6A, and is absorbed by the heat dissipation medium 160 and converted into latent heat of the heat dissipation medium 160. When the heat source 10 is in a low power mode, the above heat dissipation mechanism may enable the heat dissipation device 100 to achieve a good heat dissipation effect.

When the heat source 10 is in a high power mode, after the heat generated by the heat source 10 exceeds the latent heat that the liquid heat dissipation medium 160 may absorb, the liquid heat dissipation medium 160 begins to undergo a phase change from liquid to gas. Next, the heat dissipation medium 160 transformed into gas moves from the lateral space 1213 shown in FIG. 3 to the recess 1311 through the first slit S1 in the second heat dissipation fins assembly 132, the second slit S2 in the third heat dissipation fins assembly 137, and the third slit S3 in the fourth heat dissipation fins assembly 138 shown in FIG. 6A. Then, the gaseous heat dissipation medium 160 leaves the cavity 121 from the recess 1311 through the top space 1211 and the top opening 1215 and enters the second end 143 of the heat dissipation pipes 140 and moves toward the first end 141. Next, the gaseous heat dissipation medium 160 located in the heat dissipation pipes 140 performs heat exchange with the first heat dissipation fins assembly 150 connected to the heat dissipation pipes 140, so that the heat dissipation medium 160 is converted from a high-pressure gaseous state to a low-pressure gaseous state or a liquid state. Since the inner wall of the heat dissipation pipe 140 is a smooth surface, the heat dissipation medium 160 converted into low-pressure gas or liquid continues to move toward the first end 141 of the heat dissipation pipe 140 and flow back into the cavity 121 to complete the cycle and re-performs heat exchange with the heat conducting block 130.

That is, the heat dissipation device 100 of this embodiment may enable the heat dissipation medium 160 to cycle as described above without an additional pump as a result of the pressure and temperature of the gaseous heat dissipation medium 160 located in the recess 1311 being higher than the pressure and temperature of the heat dissipation medium 160 located at the second end 143 of the heat dissipation pipe 140.

To sum up, in the heat dissipation device of the disclosure, the heat generated by the heat source is transmitted to the heat dissipation medium through the heat conducting base and the heat conducting block. After the heat dissipation medium absorbs a certain amount of heat, the heat dissipation medium undergoes a phase change from liquid to gas. The gaseous heat dissipation medium flows upward from the top opening through the second end into the heat dissipation pipes due to the pressure difference and the temperature difference, and performs heat exchange with the first heat dissipation fins assembly in the process of flowing through the heat dissipation pipes. Finally, the heat dissipation medium flows out of the heat dissipation pipes from the first end and flows into the cavity, thus completing the cycle. Accordingly, the heat dissipation device of the disclosure may cycle the heat dissipation medium without an additional pump to effectively transfer the heat generated by the heat source to the outside, thereby achieving a good heat dissipation effect. In addition, in one embodiment, the heat conducting block has a second heat dissipation fins assembly, a third heat dissipation fins assembly and a fourth heat dissipation fins assembly, which may further enhance the heat dissipation effect of the heat dissipation device.