US20110155361A1

US20110155361A1 - Heat dissipation module and portable device having the heat dissipation module

Info

Publication number: US20110155361A1
Application number: US12/926,605
Authority: US
Inventors: Jun-Min Yang; Chien-Yi Huang; Hao-Chun Hsieh; Hsin-Lun Tsai; Chia-Hsien Lee
Original assignee: Wistron Corp
Current assignee: Wistron Corp
Priority date: 2009-12-29
Filing date: 2010-11-30
Publication date: 2011-06-30
Also published as: TW201124069A

Abstract

A heat dissipation module for lowering the temperature of a heating element is disclosed. The heat dissipation module comprises a heat dissipation module body, a container, and a liquid element. The heat dissipation module body is made of a heat conductive material; the container is installed in the heat dissipation module body; and the liquid element is disposed in the container. Therefore, when the heat dissipation module is in contact with the heating element, heat generated by the heating element is absorbed by the heat dissipation module body and the liquid element.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a heat dissipation module and a portable device; more particularly, the present invention relates to a heat dissipation module and a portable device having the capability of lowering the temperature of a heating element.
2. Description of the Related Art
Generally, an electronic device comprises various kinds of circuit boards, and each circuit board has various kinds of heating elements (such as a chip). When the heating element is working, it generates a huge amount of heat, thereby increasing its temperature. If the heat cannot be effectively and immediately dissipated, the operation of the electronic device may be affected. More seriously, the heating element might be damaged due to overheating. In order to ensure that the heating element can work properly, it is common practice to install a heat dissipation module on the heating element, so as to conduct the heat generated by the heating element to the heat dissipation module and thereby achieve the object of lowering the temperature of the heating element.
There are two major types of heat dissipation modules—an active heat dissipation module and a passive heat dissipation module. An active heat dissipation module, such as a cooling fan or a water-cooling device, needs additional driving energy to perform a heat dissipation action. A passive heat dissipation module, such as a cooling fin, does not need additional driving energy. Although an active heat dissipation module has a better heat dissipation effect than that of a passive heat dissipation module, an active heat dissipation module has a higher cost and needs a larger space for installation. Therefore, an active heat dissipation module is more suitable for installation in a large-scale electronic device (such as the motherboard of a desktop computer). As a result, the scope of applications of an active heat dissipation module is much smaller than that of a passive heat dissipation module.
With regard to a modern passive heat dissipation module, in order to enhance its heat dissipation effect, a layer of thermal grease is applied on a surface of the passive heat dissipation module that is in contact with the heating element so as to increase the heat conductivity; in addition, the volume of the passive heat dissipation module is enlarged to absorb more heat, or the passive heat dissipation module is designed with fin-like protrusions so as to increase the surface area for heat dissipation.
However, because a passive heat dissipation module is usually made of metal, the following drawbacks are inherent in practical production applications: (1) Because the specific heat of metal is low, the passive heat dissipation module and the heating element reach thermal equilibrium in a short amount of time, which makes the temperature of the heating element rise or fall very quickly; such rapid changes in temperature result in a thermal impact on the heating element and may easily damage the heating element. (2) Because some of the circuit boards of an electronic device need to be vertically installed, the weight of a passive heat dissipation module made of metal, due to the higher specific gravity, might cause the circuit boards to bend and thereby affect the reliability of the electronic device.
In the known prior art, such as Taiwan Patent No. I308047 (Heat dissipation device), a heat dissipation device is disclosed for being used to dissipate heat of an electronic element. The heat dissipation device comprises a heat absorbing portion, a heat dissipating portion jointed with the heat absorbing portion, and a heat storage body jointed with the heat absorbing portion. The heat storage body is a container made of a heat conductive material, and is filled with a phase change material. The phase change material is solid at a normal temperature, and changes from solid to liquid upon being heated. The heat absorbing portion is a base which is directly contacted to a heating electronic element. The heat dissipating portion is a heat sink set disposed on the heat absorbing portion. However, although the known prior art discloses that the heat storage body can be filled with the phase change material, it still has the following drawbacks: (1) The jointed surface area between the heat storage body and the heat absorbing portion is limited; as a result, the heat dissipation efficiency of the heat storage body is lowered; and (2) the phase change temperature of the phase change material is fixed and thus cannot change with the temperature of the heating electronic element.
Therefore, there is a need to provide a heat dissipation module and portable device having the heat dissipation module to mitigate and/or obviate the aforementioned problems.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a heat dissipation module and a portable device having the same for lowering the temperature of a heating element.
To achieve the abovementioned object, the heat dissipation module of the invention comprises a heat dissipation module body, a container, and a liquid element. The heat dissipation module body is made of a heat conductive material; the container is installed in the heat dissipation module body; and the liquid element is disposed in the container. Therefore, when the heat dissipation module is in contact with the heating element, heat generated by the heating element can be absorbed by the heat dissipation module body and the liquid element, so as to achieve an effect of lowering the temperature of the heating element. In one embodiment of the invention, the liquid element is water.
To achieve the abovementioned object, the portable device of the invention comprises at least one heating element and at least one heat dissipation module. The at least one heat dissipation module is connected to the at least one heating element. The at least one heat dissipation module comprises a heat dissipation module body, a container, and a liquid element. The heat dissipation module body is made of a heat conductive material; the container is installed in the heat dissipation module body; and the liquid element is disposed in the container. Therefore, when the heat dissipation module is in contact with the heating element, heat generated by the heating element can be absorbed by the heat dissipation module body and the liquid element, so as to achieve an effect of lowering the temperature of the heating element. In one embodiment of the invention, the liquid element is water.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and advantages of the invention will become apparent from the following description of the accompanying drawings, which disclose several embodiments of the invention. It is to be understood that the drawings are to be used for purposes of illustration only, and not as a definition of the invention.

In the drawings, wherein similar reference numerals denote similar elements throughout the several views:

FIG. 1 illustrates a schematic drawing of a portable device according to one embodiment of the invention.

FIG. 2 illustrates a structural drawing of a heat dissipation module according to one embodiment of the invention.

FIG. 3 illustrates a structural drawing of the heat dissipation module according to another embodiment of the invention.

FIG. 4 illustrates a structural drawing of the heat dissipation module according to yet another embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Please refer to FIG. 1 and FIG. 2 of a heat dissipation module and a portable device having the heat dissipation module according to one embodiment of the invention. FIG. 1 illustrates a schematic drawing of the portable device according to one embodiment of the invention, and FIG. 2 illustrates a structural drawing of the heat dissipation module according to one embodiment of the invention.
As shown in FIG. 1, the portable device 5 of the invention comprises at least one heating element 51 and at least one heat dissipation module 1. The at least one heating element 51 is installed in, but is not limited to, a circuit board 52 of the portable device 5. The at least one heat dissipation module 1 is connected to the at least one heating element 51. In one embodiment of the invention, a layer of thermal grease (not shown in the figures) is applied on the surface of the heat dissipation module 1 that makes physical contact with the heating element 51 so as to enhance the heat conductivity efficiency, but please note that the scope of the invention is not limited to the above description. In one embodiment of the invention, the heating element 51 is, but is not limited to, a chip or other heating device of the portable device 5. In one embodiment of the invention, the heat dissipation module 1 is, but is not limited to, a passive heat dissipation module.
As shown in FIG. 1, in one embodiment of the invention, the portable device 5 is, but is not limited to, a mobile phone. For example, the portable device 5 can also be a personal digital assistant (PDA), a game console, a navigation device, or the like. Please note that in the following embodiment, the heat dissipation module 1 is applied to the portable device 5; however, the heat dissipation module 1 of the invention can be applied to any heating element 51 capable of generating heat without being limited to application to the portable device 5.
As shown in FIG. 2, the heat dissipation module 1 of the invention comprises a heat dissipation module body 10, a container 20, and a liquid element 30. The heat dissipation module body 10 comprises a plurality of fins 11; the container 20 is installed in the heat dissipation module body 10; and the liquid element 30 is disposed in the container 20. Therefore, when the heat dissipation module 1 is in contact with the heating element 51, heat generated by the heating element 51 can be absorbed by the heat dissipation module body 10 and the liquid element 30, so as to achieve an effect of lowering a temperature of the heating element 51. The fins 11 are used for increasing the surface area of the heat dissipation module 1 for heat dissipation.
In one embodiment of the invention, the heat dissipation module body 10 is made of a heat conductive material, and the heat conductive material is selected from, but is not limited to, the following material groups: aluminum, aluminum alloy, copper, copper alloy, silver, and silver alloy.
In order to solve the problem that the heat dissipation module 1 and the heating element 51 reach thermal equilibrium in a short amount of time due to a low specific heat of the metal, as mentioned in known prior arts, in one embodiment of the invention, the liquid element is water, such that it takes longer for the heat dissipation module 1 and the heating element 51 to reach thermal equilibrium because water has the characteristics of a higher specific heat and higher heat of vaporization, and therefore the influence of thermal impact on the heating element 51 can be reduced. Further, because the specific gravity of water (1 g/cm³) is lower than that of most metal materials (for example, the specific gravity of copper is 8.9 g/cm³), a larger volume of the container 20 will allow more water to be contained, and the weight of the heat dissipation module 1 can further be reduced, so as to avoid the drawback that the circuit board 52 is bent due to the weight of the heat dissipation module 1, as mentioned in known prior arts. Please note that the liquid element 30 is not limited to water; the liquid element 30 can be any liquid that has a high specific heat and high heat of vaporization.
The vaporization temperature of water at 1 standard atmospheric pressure (atm) is 100□, but most of the time, the thermal equilibrium temperature of the heating element 51 and the heat dissipation module 1 remains below 100□. In order to make the vaporization temperature of water match the thermal equilibrium temperature of the heating element 51 and the heat dissipation module 1, the invention provides a mechanism capable of changing the vaporization temperature of the liquid element 30 of the heat dissipation module 1.
As shown in FIG. 2, in one embodiment of the invention, the container 20 comprises a port 21. The port 21 is disposed on the exterior of the heat dissipation module body 10. The heat dissipation module 1 further comprises an on/off element 40. The on/off element 40 is separately connected to the port 21. In one embodiment of the invention, the on/off element 40 can be, but is not limited to, a pressure valve or a bolt. The liquid element 30 can be infused into the container 20 via the port 21, and the pressure of the liquid element 30 can reach a specific external pressure via the port 21. More precisely, the heat dissipation module 1 can be placed in a space (not shown in the figures) at a specific pressure, wherein the space has a specific external pressure with regard to the heat dissipation module 1. When the on/off element 40 is not connected to the port 21, the pressure of the liquid element 30 will gradually reach the specific external pressure. Therefore, the pressure of the liquid element 30 can be changed, so as to accordingly change the vaporization temperature of the liquid element 30. In one embodiment of the invention, the pressure of the liquid element 30 is substantially between 0.4 and 1 atm. Please note that the correlation between the pressure and the vaporization temperature of the liquid element 30 can be found by means of referring to the third-phase diagram of the liquid element 30. Because the technique of utilizing the pressure to change the vaporization temperature or solidification temperature of a material is widely and commonly applied by those skilled in the art, and this is not the major characteristic of the invention, there is no need for further description.
Please refer to FIG. 3; in another embodiment of the invention, the container 20 a is a multi-layer structure installed in the heat dissipation module body 10 a, so as to increase the contact area of the container 20 a and the heat dissipation module body 10 a and thereby increase the heat conductivity efficiency of the heat dissipation module 1 a.
Please refer to FIG. 4; in yet another embodiment of the invention, the container 20 b is an S-shaped structure installed in the heat dissipation module body 10 b, so as to increase the contact area of the container 20 b and the heat dissipation module body 10 b and thereby increase the heat conductivity efficiency of the heat dissipation module 1 b.
According to the above description, the heat dissipation module 1 of the invention has the following advantages: (1) extending the time of reaching thermal equilibrium so as to prolong the usage life of the portable device; and (2) reducing the weight of the heat dissipation module.
Although the invention has been explained in relation to its preferred embodiments, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.

Claims

1. A heat dissipation module, used for lowering the temperature of a heating element, the heat dissipation module comprising:

a heat dissipation module body, made of a heat conductive material;

a container, installed in the heat dissipation module body; and

a liquid element, disposed in the container;

wherein when the heat dissipation module is in contact with the heating element, heat generated by the heating element is absorbed by the heat dissipation module body and the liquid element so as to achieve an effect of lowering the temperature of the heating element.

2. The heat dissipation module as claimed in claim 1, wherein the pressure of the liquid element is substantially between 0.4 and 1 standard atmospheric pressure (atm).

3. The heat dissipation module as claimed in claim 1, wherein the container comprises a port, which is disposed on the exterior of the heat dissipation module body, the heat dissipation module further comprising an on/off element, which is separately connected to the port, and the pressure of the liquid element can reach a specific external pressure via the port.

4. The heat dissipation module as claimed in claim 1, wherein the container is a multi-layer or S-shaped structure installed in the heat dissipation module body.

5. The heat dissipation module as claimed in claim 1, wherein the liquid element is water.

6. The heat dissipation module as claimed in claim 1, wherein the heat dissipation module body comprises a plurality of fins.

7. The heat dissipation module as claimed in claim 1, wherein the heat conductive material is selected from the following material groups: aluminum, aluminum alloy, copper, copper alloy, silver and silver alloy.

8. The heat dissipation module as claimed in claim 1, wherein the heat dissipation module is a passive heat dissipation module.

9. A portable device, comprising:

at least one heating element; and

at least one heat dissipation module, connected to the at least one heating element, the at least one heat dissipation module comprising:

a heat dissipation module body, made of a heat conductive material;

a container, installed in the heat dissipation module body; and

a liquid element, disposed in the container;

10. The portable device as claimed in claim 9, wherein the pressure of the liquid element is substantially between 0.4 and 1 standard atmospheric pressure (atm).

11. The portable device as claimed in claim 10, wherein the container comprises a port, which is disposed on the exterior of the heat dissipation module body, the heat dissipation module further comprising an on/off element, which is separately connected to the port, and the pressure of the liquid element can reach a specific external pressure via the port.

12. The portable device as claimed in claim 9, wherein the container is a multi-layer or S-shaped structure installed in the heat dissipation module body.

13. The portable device as claimed in claim 9, wherein the liquid element is water.

14. The portable device as claimed in claim 9, wherein the heat conductive material is selected from the following material groups: aluminum, aluminum alloy, copper, copper alloy, silver, and silver alloy.

15. The portable device as claimed in claim 9, wherein the heat dissipation module body comprises a plurality of fins.