CN106972096A - A kind of heat-dissipating structure body and application - Google Patents

Abstract

The invention relates to a heat dissipation structure and its application. The flat plate made of graphite-metal composite material is fixed on the metal heat sink to obtain the heat dissipation structure of the present invention, so that the heat dissipation structure maintains the excellent characteristics of the graphite-metal composite material, and at the same time, the existence of the metal heat sink also compensates for the graphite-metal heat dissipation structure. The defect of low mechanical strength of the metal composite material is used to obtain a relatively cheap heat dissipation structure with excellent heat dissipation performance and sufficient mechanical strength. The heat dissipation structure can effectively reduce the temperature of semiconductor devices including LEDs, can effectively prolong the service life of various electronic devices, and has wide application prospects in the industrial range.

Description

A heat dissipation structure and its application

technical field

The invention relates to the technical field of electrical equipment, more specifically, to a heat dissipation structure with excellent heat dissipation performance and its application.

Background technique

Graphite-metal composites containing graphite materials are metal matrix composites, extrusion moldings, cold forging and other square pressure moldings, molds, etc., in which metal matrix graphite particles or graphite fibers are dispersed as materials. The sintered graphite molded body is known as a metal-dispersed graphite-based metal composite material.

On the other hand, the composite material containing graphite has a thermal diffusivity of 1.5-3cm ² /sec, which is higher than that of widely used heat conductors such as aluminum and aluminum nitride of 0.7-1.0cm ² /sec. Much larger and, as such, are known for their superior thermal performance.

In other respects, composite materials containing graphite, for example, the bending strength of graphite composite materials using aluminum extrusion materials is 30-40Mpa, and the modulus of elasticity is 12Gpa. Only aluminum, magnesium, titanium, copper, iron and other commonly used metals 1/10 of the strength. Furthermore, heat sinks such as aluminum extruded materials are relatively inexpensive because they can be mass-produced. Compared with graphite-metal composite materials, although the heat dissipation performance is better, the price is relatively high.

Contents of the invention

One of the technical problems to be solved by the present invention is to compensate for its weak mechanical properties while maintaining the excellent properties of the graphite-metal composite material, so as to provide a relatively cheap heat dissipation structure with excellent heat dissipation performance.

The second technical problem to be solved by the present invention is to solve the life shortening and failure problems of LED modules and high-load semiconductor integrated circuit boards including IGBTs due to high temperature.

The technical solution of the present invention to solve the above problems is to provide a heat dissipation structure, including a bonded graphite-metal composite material layer and a metal heat sink, and the graphite-metal composite material layer is pressed into a flat plate shape by graphite-metal composite material and cut.

In the heat dissipation structure provided by the present invention, aluminum, copper or aluminum/copper alloy are melted and impregnated under high pressure in the voids of graphite materials with a porosity of 5-40% made of artificial graphite and/or natural graphite powder to obtain The graphite-metal composite material.

In the heat dissipation structure provided by the present invention, the graphite-metal composite material is obtained by using a graphite material with a porosity of 5-25%.

In the heat dissipation structure provided by the present invention, the graphite-metal composite material layer and the metal heat sink are fixed by fasteners or combined with electroplating; the metal heat sink is made of aluminum, copper or aluminum/copper alloy .

In the heat dissipation structure provided by the present invention, thermal grease is coated between the graphite-metal composite material layer and the metal heat sink.

The present invention also provides an LED module. The LED element is arranged on the electrical insulation layer of a copper foil or aluminum foil circuit board, and embedded in a flat plate made of graphite-metal composite material to form an LED module.

In the LED module provided by the present invention, aluminum, copper or aluminum/copper alloy are melted and impregnated with high pressure in the voids of graphite material with a porosity of 5-40% made of artificial graphite and/or natural graphite powder to obtain graphite - Metal composites.

The present invention also provides an LED lamp, wherein the LED module is fixed on a metal heat sink to form an LED lamp.

In the LED lamp provided by the present invention, the flat plate made of graphite-metal composite material of the LED module is bonded to the metal heat sink.

In the LED lamp provided by the present invention, the flat plate made of graphite-metal composite material and the metal heat sink are fixed by fasteners or combined with electroplating; the metal heat sink is made of aluminum, copper or aluminum/copper alloy production.

Implementing the present invention has the following beneficial effects: the flat plate made of graphite-metal composite material is fixed on the metal heat sink to obtain the heat dissipation structure of the present invention, so that the heat dissipation structure maintains the excellent characteristics of graphite-metal composite material, and at the same time, the metal The existence of the heat sink also makes up for the defect of low mechanical strength of the graphite-metal composite material, thereby obtaining a relatively cheap heat dissipation structure with excellent heat dissipation performance and sufficient mechanical strength. The heat dissipation structure can effectively reduce the temperature of semiconductor devices including LEDs, can effectively prolong the service life of various electronic devices, and has wide application prospects in the industrial range.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings without making creative efforts.

Fig. 1 is a side view of a preferred application mode of the heat dissipation structure of the present invention;

Fig. 2 is a front view of a preferred application mode of the heat dissipation structure of the present invention;

Fig. 3 is a schematic structural diagram of a preferred embodiment of the LED module of the present invention.

detailed description

Embodiments of the present invention will be specifically described below in conjunction with the accompanying drawings.

Graphite-metal composites have excellent heat dissipation properties, but their high price and weak mechanical properties limit the widespread use of this high-quality material in electrical equipment.

The main innovation of the present invention is that the flat plate made of graphite-metal composite material is fixed on the metal heat sink to obtain the heat dissipation structure of the present invention, so that the heat dissipation structure maintains the excellent characteristics of graphite-metal composite material, and at the same time, the metal heat dissipation The existence of the flakes also makes up for the defect of low mechanical strength of the graphite-metal composite material, thereby obtaining a relatively cheap structure with excellent heat dissipation performance and sufficient mechanical strength.

Fig. 1 is a side view of a preferred application mode of the heat dissipation structure of the present invention. As shown in Fig. 1, the heat dissipation structure includes a bonded graphite-metal composite material layer 102 and a metal heat sink 103, and the graphite-metal composite material Layer 102 is formed from a graphite-metal composite material pressed into a flat sheet and cut. The heating element 101 is installed on the surface of the graphite-metal composite material layer 102 .

The manufacture of graphite-metal composite materials can be processed by molten forging method, pressure impregnation method. For example, aluminum, copper or aluminum/copper alloy is melted and impregnated under high pressure into the voids of graphite material with a porosity of 5-40% made of artificial graphite and/or natural graphite powder to obtain a graphite-metal composite material. The graphite powder utilized at this time can be natural graphite and/or artificial graphite, and graphite sold in the general market can also be used. In the present invention, natural graphite is preferred to prepare graphite-metal composite materials. For example, various graphitized powders formed by subsequent processes such as coke are used, and binders such as tar, pitch, or organic resins are used, and extrusion molding, cold forging, etc. are used. Formed bodies are produced through processes such as square pressure forming and abrasive forming. Thereafter, as needed, the asphalt can be impregnated repeatedly, and finally heated to above 2500°C for treatment, which can approach 100% graphite structure.

The graphite material used in the present invention has a porosity of 5-40%, more than 95% of which is impregnated with metal material. If the porosity reaches more than 40%, the thermal expansion rate of the graphite-metal composite material will decrease while the thermal expansion rate will decrease. Therefore, the ideal porosity is 5-25%.

The graphite-metal composite material obtained above can be easily processed into a plate shape due to its excellent processing performance, especially a plate with a thickness of several millimeters or less. It can be used as a substrate with excellent heat dissipation for attaching LEDs and IGBTs. (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor) and other integrated circuits, including high-load semiconductors, quickly dissipate the heat generated by these heat-generating components.

Among the metals used to prepare graphite-metal composite materials, when aluminum and aluminum alloys are used, they are JIS (Japanese Alloy Standard) stretched materials, such as JIS casting alloys, JIS die-casting alloys, and the like. Where copper and copper alloys are used, JIS extruded copper-based alloys can be used.

Fig. 2 is a front view of a preferred application mode of the heat dissipation structure of the present invention. As shown in Fig. 2, the heat dissipation structure obtained above adopts a graphite-metal alloy with excellent thermal diffusivity at the position connected to the heating element. Combining composite materials with metal heat sinks 103 made of aluminum, copper or aluminum/copper alloy materials with a large heat dissipation surface area results in a heat dissipation structure with excellent heat dissipation.

The graphite-metal composite material layer 102 and the metal heat sink 103 are fixed by fasteners, such as screws; electroplating on their contact surfaces, that is, electroplating and fixing, such as soldering, can also be used. After the graphite-metal composite material layer 102 and the metal heat sink 103 are fixed, a heat conduction grease is coated between the graphite-metal composite material layer 102 and the metal heat sink 103 , such as silicone grease, which is good for heat conduction.

The metal heat sink 103 is made of aluminum, copper or aluminum/copper alloy. It can be made by extrusion molding, mold casting, die casting, etc., especially in combination with calendered sheet. The heat dissipation surface of the metal heat sink 103 is in contact with the atmosphere, or used in combination with a heat dissipation fan.

In this embodiment, the heat generated by the heating element 101 (including LED modules, IGBTs or other integrated circuit boards) can be efficiently diffused through the graphite-metal composite material, and dissipated through the high-strength radiator fan with a large surface area. heat, forming an economical and high-performance construction.

Fig. 3 is a structural schematic diagram of a preferred embodiment of the LED module of the present invention. As shown in Fig. 3, the LED element 201 is arranged on the electrical insulation layer 204 of a copper foil or aluminum foil circuit board, and embedded in a graphite-metal composite material. On the flat plate 202, LED modules are made. Since the LED module adopts the COB (CHIP ON BOARD, chip on board packaging) method, it has outstanding advantages. Due to the lowering of temperature, the illuminance of this LED module is greatly increased, and the service life is greatly extended, which makes it possible to produce LEDs more economically. Copper foil and aluminum foil can be used as the wiring pattern. At the same time, the insulating layer can use organic films such as amides, aramid fibers, and imides with good heat resistance or use ceramic sheets.

Of course, it is also possible to directly arrange the LED element 201 on the electrical insulating layer 204 of the copper foil or aluminum foil circuit board and embed the heat dissipation structure in the foregoing embodiment, or fix the LED module in the foregoing embodiment on the metal heat sink 203 , made of LED lights. In the LED lamp of this embodiment, the flat plate 202 made of the graphite-metal composite material is bonded to the metal heat sink 203. Since the metal heat sink 203 is used, the weak point of insufficient mechanical strength of the graphite-metal composite material is made up, so that the performance with intensity. Moreover, compared with all graphite-metal composite materials, the price is relatively low. Especially in the case of COB, the sapphire material with high thermal resistance in the LED element 201 is omitted, and the heat dissipation and economy are self-evident.

Example 1

A graphite block (manufactured by Tokai Carbon) with a size of 150mm x 200mm x 250mm was kept in an argon atmosphere at 700°C. Press to 65Mpa and cast to obtain graphite-metal composite material.

The graphite-metal composite material was taken out from the casting, and its thermal diffusivity was measured to be 2.5 cm ² /sec. Further, cut the 2cm-thick board into a 60cm-square board shape, stick a 60μm-thick aramid resin on it, and form a wiring pattern with copper foil on it, and configure 40 LED elements according to the COB method ( 201) (SEOUL CERACON SV1400), complete the module. On it, the heat-receiving part of the aluminum heat sink is Φ90mm, and the casing composed of 20 fans with a length of 50mm and a width of 15mm is fixed with screws to become a 40W LED lamp. This lamp was energized with a voltage of 115V and a current of 350mA.

Table 1 shows the measurement results of the illuminance and the temperature of each part after the above-mentioned LED lamp was turned on for 24 hours.

Comparative example 1

In Example 1, an aluminum plate was used to replace the graphite-metal composite material, and an LED lamp was also made to be energized. Since the lamp was extinguished after 1 hour, the illuminance and temperature results were measured 30 minutes after energization, as shown in Table 1.

Comparative example 2

In Example 1, instead of COB, a sapphire module was used under the commonly used LED element to make the same LED lamp and energize it. The measured illuminance and temperature results of each part after 24 hours are shown in Table 1.

Table 1 Illuminance and temperature measurement results

Example 2

In Example 1, an IGBT with a calorific value of 110 W was fixed on a graphite-metal composite plate cut into 80 mm×40 mm and a thickness of 3 mm with screws. On the heated part of 80mm×40mm, 30 fan aluminum heat sinks with a height of 30mm are fixed with graphite-metal composite materials and then energized. The temperature of the composite material is determined to be 45°C, and the temperature of the heat sink fan is 36°C.

Comparative example 3

In Example 2, C1100 is used instead of the graphite-metal composite material of the same size to be energized, the temperature of C1100 is 78°C, and the temperature of the heat sink is 56°C.

The heat dissipation structure composed of graphite-metal composite material and metal heat sink of the present invention can effectively reduce the temperature of semiconductor devices including LEDs, effectively prolong the life of various electronic equipment, and has wide application prospects in the industrial range .

Embodiments of the present invention have been described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementations, and the above-mentioned specific implementations are only illustrative, rather than restrictive, and those of ordinary skill in the art will Under the enlightenment of the present invention, many forms can also be made without departing from the gist of the present invention and the protection scope of the claims, and these all belong to the protection of the present invention.

Claims (10)

1. a kind of heat-dissipating structure body, it is characterised in that graphite-metal composite layer (102) and heat dissipation metal including laminating Piece (103), the graphite-metal composite layer (102) is pressed into tabular and the system of cutting by graphite-metal composite .

2. heat-dissipating structure body according to claim 1, it is characterised in that with height after aluminium, copper or aluminium/copper alloy are melted The voidage that pressure dipping is made up of Delanium and/or natural graphite powder is described in the space of 5-40% graphite materials, obtaining Graphite-metal composite.

3. heat-dissipating structure body according to claim 2, it is characterised in that obtained using voidage for 5-25% graphite materials The graphite-metal composite.

4. heat-dissipating structure body according to claim 1, it is characterised in that the graphite-metal composite layer (102) and The metal fin (103) is fixed or electroplated using fastener with reference to fixation；Metal fin (103) the use aluminium, Copper or aluminium/copper alloy are made.

5. heat-dissipating structure body according to claim 1, it is characterised in that the graphite-metal composite layer (102) and Thermally conductive grease is coated between the metal fin (103).

6. a kind of LED module, it is characterised in that LED sub-primes (201) are arranged on to the electric insulation layer of copper foil or aluminium foil wiring board (204) on, and it is embedded on the flat board (202) that graphite-metal composite is made, LED module is made.

7. LED module according to claim 6, it is characterised in that with high pressure after aluminium, copper or aluminium/copper alloy are melted It is in the space of 5-40% graphite materials, to obtain graphite-gold to impregnate the voidage being made up of Delanium and/or natural graphite powder Belong to composite.

8. a kind of LED, it is characterised in that the LED module in claim 5 or 6 is fixed on metal fin (203) On, LED is made.

9. LED according to claim 8, it is characterised in that the graphite-metal composite of the LED module is made Flat board (202) fitted with the metal fin (203).

10. LED according to claim 8, it is characterised in that the flat board that the graphite-metal composite is made (202) fix or electroplate using fastener with reference to fixation with the metal fin (203)；The metal fin (203) It is made using aluminium, copper or aluminium/copper alloy.