CN206947325U - A graphite copper foil composite heat sink - Google Patents

Abstract

The utility model belongs to the technical field of the fin, especially, relate to a graphite copper foil composite cooling fin, including netted copper foil to and through the graphite film of calendering molding technique complex in at least one side of netted copper foil, the porosity of netted copper foil is 40 ~ 80%, and the aperture size is 0.002 ~ 2 mm. Compared with the prior art, the utility model discloses a calendering technique compounds graphite membrane on netted copper foil, owing to need not to use the adhesive, consequently greatly reduced interface thermal resistance, effectively avoided composite cooling fin to produce the phenomenon of coming unstuck between the layer simultaneously to make composite cooling fin have excellent mechanical properties and heat conduction heat dispersion, and improved composite cooling fin's life; in addition, if the porosity of the copper foil is too high, the mechanical strength of the copper foil can be influenced, and if the porosity is too low, the bonding strength between the copper foil and the graphite film can be influenced; and too big mesh can make graphite membrane and copper foil closely combine, and the mesh undersize can lead to the not enough cohesion of graphite membrane and copper foil.

Description

A graphite copper foil composite heat sink

technical field

The utility model belongs to the technical field of heat sinks, in particular to a graphite-copper foil composite heat sink.

Background technique

With the development of large-scale integrated circuits and packaging technology, electronic components and electronic equipment are developing in the direction of thin, light and small, the integration of electronic products is getting higher and higher, and the number of electronic components per unit area is increasing geometrically. , heat dissipation has become a very prominent problem. If the heat is not dissipated in time, it will cause the operating temperature of the components to rise, and in severe cases, the electronic components will fail, which will directly affect the life and reliability of various high-precision equipment using them. . Therefore, how to dissipate heat has become a bottleneck in the miniaturization and integration of electronic products.

At present, some products in the market use metal materials for heat conduction and heat dissipation, especially copper and aluminum. Although the thermal conductivity of copper is 398W/mK, its heavy weight and easy oxidation limit its application, while the thermal conductivity of aluminum is 237W/mK. It is difficult to meet the needs of existing products for heat conduction and heat dissipation.

Among the materials that can be used for heat dissipation, carbon materials have become the focus of research because of their excellent thermal conductivity. For example, carbon nanotubes have a very large aspect ratio, and the heat exchange performance along the length direction is very high. The thermal conductivity is more than 10 times that of metallic silver, and high thermal conductivity can be obtained with a small number of additions; Graphene material is currently the thinnest material in the world, only one carbon atom thick; and graphene is highly stable, and as a thermal conductor, the thermal conductivity of graphene is about 4000W/mK, which is 5 times that of copper. With the continuous deepening of research, carbon materials will become more ideal materials in the field of heat conduction. They are used in computer technology, communications, electronics and other fields. They are the most promising type of heat dissipation materials in recent years.

However, existing carbon materials also have deficiencies, such as poor folding resistance of graphene materials, weak strength of materials, easy tearing or damage due to displacement of adhered parts and surface material falling off, and because of the structure of the material itself Characteristics, the thermal conductivity of carbon nanotubes and graphene in the longitudinal direction Z is low, generally 5-30W/mK.

Therefore, in order to effectively maintain the original high heat dissipation of carbon materials, and at the same time enable it to have excellent mechanical properties and high longitudinal thermal conductivity, in the prior art, the usual practice is to combine carbon materials with double-sided adhesive tape and Copper foil is compounded to form a composite heat sink of copper foil-double-sided adhesive-graphite; as the Chinese patent CN 205685874 U discloses a nano-copper carbon graphite sheet, the graphite sheet is composed of a cover film, an acrylic glue layer, a nano-carbon coating, a copper Foil, nano-carbon coating, acrylic glue layer and release film. In addition, there is a Chinese patent CN 103476227 A which discloses a copper-carbon composite heat sink and a preparation method thereof, in which a carbon heat-conducting layer is coated on both sides of a copper foil with an adhesive.

Although the above-mentioned copper-carbon composite heat sink has a certain tensile strength and good thermal conductivity and heat dissipation performance, it has the following defects: first, the copper-carbon composite heat sink is bonded together with copper foil and graphite through an adhesive layer, However, due to the poor thermal conductivity of the adhesive, it will hinder the dissipation of heat, which greatly reduces the heat dissipation effect of the composite heat sink; second, the composite heat sink with copper foil-double-sided adhesive-graphite structure is generally only suitable for low-power products. heat dissipation, such as mobile phones, micro components, etc.; it cannot be applied to heat dissipation of high-power products (such as electric vehicles); third, when adhesives are used for bonding, the bonding force between the layers is too low, and it is easy to It leads to debonding between layers, which affects the heat dissipation performance and service life of the composite heat sink.

In view of this, it is indeed necessary to further improve the existing composite heat sink, so that it has excellent heat conduction and heat dissipation performance, and at the same time can effectively expand the application range and service life of the composite heat sink.

Utility model content

The purpose of the utility model is to provide a graphite-copper-foil composite radiator for the deficiencies of the prior art to solve the problem of low heat dissipation efficiency, narrow application range, easy interlayer degumming and short service life of the existing composite radiator. question.

In order to achieve the above object, the utility model adopts the following technical solutions:

A graphite-copper-foil composite heat sink, comprising a mesh-shaped copper foil, and a graphite film compounded on at least one side of the mesh-shaped copper foil by calendering technology, the porosity of the mesh-shaped copper foil is 40-80%, and the The aperture size of the mesh copper foil is 0.002-2mm. Among them, the porosity and pore size of the mesh copper foil in the utility model are very important, if the porosity is too high, it will affect the mechanical strength of the copper foil; if the porosity is too low, it will affect the bonding strength between the copper foil and the graphite film; In addition, if the mesh is too large, the graphite film cannot be tightly combined with the copper foil; if the mesh is too small, the bonding force between the graphite film and the copper foil will be insufficient.

As an improvement of the graphite copper foil composite heat sink of the utility model, the porosity of the mesh copper foil is 50-70%.

As an improvement of the graphite-copper-foil composite heat sink of the utility model, the mesh-shaped copper foil has an aperture size of 0.01-1 mm.

As an improvement of the graphite-copper foil composite heat sink of the utility model, the thermal conductivity of the heat sink in the horizontal direction is 1500-2500 W/m·K, and the thermal conductivity in the vertical direction is 500-1000 W/m·K. After the calendering and compounding of the mesh copper foil and the graphite film, the heat conduction and heat dissipation performances of the heat sink in the horizontal direction and the vertical direction are effectively improved.

As an improvement of the graphite-copper foil composite heat sink of the utility model, the thickness of the mesh copper foil is 0.01-2 mm. If the thickness of the copper foil is too thin, the tensile strength of the composite heat sink will be greatly reduced; if the thickness of the copper foil is too thick, the flexibility of the composite heat sink will be greatly reduced, and the material cost will be increased.

As an improvement of the graphite-copper foil composite heat sink of the utility model, the thickness of the graphite film is 0.01-1 mm. If the thickness of the graphite film is too thin, the thermal conductivity of the composite heat sink will be greatly reduced; if the thickness of the graphite film is too thick, the bonding force between the graphite film and the copper foil will be greatly reduced, and the service life of the composite heat sink will be affected.

As an improvement of the graphite-copper foil composite heat sink of the utility model, the mesh shape of the mesh copper foil is circular, elliptical or polygonal.

As an improvement of the graphite-copper foil composite heat sink of the present invention, the graphite film is an artificial graphite film or a natural graphite film; it is preferably an artificial graphite film, because the thermal conductivity of the artificial graphite film is 3 to 5 times that of the natural graphite film , at the same time, it is easy to die-cut, and has the outstanding characteristics of rapid heat dissipation from point to surface.

As an improvement of the graphite-copper-foil composite cooling fin of the present invention, its preparation method comprises the following steps:

Step 1. Select a polymer film material as a raw material, place it in a carbonization furnace to heat up to the carbonization temperature, and carry out carbonization, then move the carbonized material to a graphitization furnace for graphitization, and then take it out and roll it to obtain a graphite film;

Step 2, firstly carry out surface cleaning treatment on the copper foil, and then carry out punching treatment to obtain mesh copper foil;

Step 3: Evenly spread the graphite film prepared in Step 1 on the net-shaped copper foil obtained in Step 2, and then perform rolling in stages to obtain the graphite-copper foil composite heat sink.

As an improvement of the graphite-copper foil composite heat sink of the present invention, the rolling pressure in step 3 is 20-60 kg/cm ³ , and the rolling speed is 0.5-2.5 m/min.

As an improvement of the graphite-copper foil composite heat sink of the utility model, the carbonization temperature in step 1 is 800-1400°C, and the carbonization time is 5-10h; the graphitization temperature is 2200-2800°C, and the graphitization time is 5-10h.

As an improvement of the graphite copper foil composite heat sink of the present invention, the polymer film material is at least one of polyimide, polyamide, polybenzoxazole, polybenzobisoxazole and polythiazole , preferably polyimide.

The beneficial effects of the utility model are: a graphite-copper foil composite heat sink of the utility model, comprising a mesh copper foil, and a graphite film compounded on at least one side of the mesh copper foil by calendering forming technology, the mesh copper foil The porosity of the foil is 40-80%, and the pore size is 0.002-2mm. Compared with the prior art, the utility model adopts the calendering technology to compound the graphite film on the mesh copper foil. Since no adhesive is used, the interface thermal resistance is greatly reduced, and at the same time, the interlayer degumming phenomenon of the composite heat sink is effectively avoided. , so that the composite heat sink has excellent mechanical properties and thermal conductivity and heat dissipation performance; moreover, the porosity and pore size of the mesh copper foil are very important. If a dense copper foil without mesh is used, the distance between the copper foil and the graphite film The bonding force is poor; the use of mesh copper foil can make the copper foil and the graphite film tightly bonded together through the mesh; if the porosity is too high, it will affect the mechanical strength of the copper foil; if the porosity is too low, it will affect the copper foil and the graphite film. In addition, if the mesh is too large, the graphite film cannot be tightly combined with the copper foil; if the mesh is too small, the bonding force between the graphite film and the copper foil will be insufficient.

Description of drawings

Fig. 1 is one of structural representations of the utility model.

Fig. 2 is the second structural diagram of the utility model.

In the picture: 1-mesh copper foil; 2-graphite film.

detailed description

The utility model will be further described in detail below in conjunction with the specific implementation and the accompanying drawings, but the implementation of the utility model is not limited thereto.

Example 1

As shown in Figure 1, a graphite-copper foil composite heat sink includes a mesh copper foil 1, and a graphite film 2 compounded on the mesh copper foil 1 by calendering technology, wherein the thickness of the mesh copper foil 1 is 0.5 mm, the thickness of the graphite film 2 is 0.05mm; the porosity of the mesh copper foil 1 is 60%, and the aperture size is 0.01mm; the thermal conductivity of the composite heat sink is 2000W/m K in the horizontal direction, and the thermal conductivity in the vertical direction is 800W/m·K.

The preparation method of the composite heat sink comprises the following steps:

Step 1. Select polyimide as the raw material, place it in a carbonization furnace for carbonization, the carbonization temperature is 1000°C, and the carbonization time is 8 hours; then move the carbonized material to the graphitization furnace for graphitization, the graphitization temperature The temperature is 2500°C, the graphitization time is 8 hours, and the graphite film 2 is obtained by calendering after taking it out;

Step 2: Cleaning the surface of the copper foil first, and then performing a punching process to obtain a mesh copper foil 1;

Step 3. Evenly spread the graphite film 2 obtained in Step 1 on the netted copper foil 1 obtained in Step 2, and then perform rolling in stages. The rolling pressure is 40kg/cm ³ , and the roll speed is 1.0m /min, the graphite-copper-foil composite heat sink is obtained.

Comparative example 1

The difference from Example 1 is that the composite heat sink in this comparative example uses an adhesive to compound the graphite film on the surface of the copper foil to form a composite heat sink with a sandwich structure of copper foil-adhesive layer-graphite film.

Example 2

As shown in Figure 2, a graphite-copper foil composite heat sink includes a mesh copper foil 1, and a graphite film 2 compounded on both sides of the mesh copper foil 1 by calendering technology, wherein the mesh copper foil 1 The thickness is 0.01mm, and the thickness of the single-layer graphite film 2 is 0.01mm; the porosity of the mesh copper foil 1 is 40%, and the aperture size is 0.002mm; the horizontal thermal conductivity of the composite heat sink is 1500W/m·K, The thermal conductivity in the vertical direction is 500W/m·K.

The preparation method of the composite heat sink comprises the following steps:

Step 1. Select polybenzoxazole as a raw material, place it in a carbonization furnace for carbonization, the carbonization temperature is 800°C, and the carbonization time is 5 hours; then move the carbonized material to the graphitization furnace for graphitization, graphitization The temperature is 2200°C, the graphitization time is 5 hours, and the graphite film 2 is obtained by calendering after taking it out;

Step 2: Cleaning the surface of the copper foil first, and then performing a punching process to obtain a mesh copper foil 1;

Step 3. Evenly spread the graphite film 2 prepared in Step 1 on the netted copper foil 1 obtained in Step 2, and then perform rolling in stages. The rolling pressure is 20kg/cm ³ , and the roll speed is 0.5m /min, the graphite-copper-foil composite heat sink is obtained.

Comparative example 2

The difference from Example 2 is that the composite heat sink in this comparative example uses an adhesive to compound the graphite film on both surfaces of the copper foil to form a graphite film-adhesive layer-copper foil-adhesive layer-graphite film structure Composite heat sink.

Example 3

As shown in Figure 2, a graphite-copper foil composite heat sink includes a mesh copper foil 1, and a graphite film 2 compounded on both sides of the mesh copper foil 1 by calendering technology, wherein the mesh copper foil 1 The thickness is 2mm, and the thickness of the single-layer graphite film 2 is 1mm; the porosity of the mesh copper foil 1 is 80%, and the aperture size is 2mm; the horizontal thermal conductivity of the composite heat sink is 2500W/m K, and the vertical thermal conductivity The coefficient is 1000W/m·K.

The preparation method of the composite heat sink comprises the following steps:

Step 1. Select polyimide as the raw material, place it in a carbonization furnace for carbonization, the carbonization temperature is 1400°C, and the carbonization time is 10h; then move the carbonized material to the graphitization furnace for graphitization, the graphitization temperature The temperature is 2800°C, the graphitization time is 10h, and the graphite film 2 is obtained by calendering after taking it out;

Step 2: Cleaning the surface of the copper foil first, and then performing a punching process to obtain a mesh copper foil 1;

Step 3. Evenly spread the graphite film 2 obtained in Step 1 on the netted copper foil 1 obtained in Step 2, and then perform rolling in stages. The rolling pressure is 60kg/cm ³ , and the roll speed is 2.5m /min, the graphite-copper-foil composite heat sink is obtained.

Comparative example 3

The difference from Example 3 is that the composite heat sink in this comparative example uses an adhesive to compound the graphite film on both surfaces of the copper foil to form a graphite film-adhesive layer-copper foil-adhesive layer-graphite film structure Composite heat sink.

Example 4

As shown in Figure 2, a graphite-copper foil composite heat sink includes a mesh copper foil 1, and a graphite film 2 compounded on both sides of the mesh copper foil 1 by calendering technology, wherein the mesh copper foil 1 The thickness is 0.1mm, and the thickness of the single-layer graphite film 2 is 0.02mm; the porosity of the mesh copper foil 1 is 50%, and the aperture size is 0.5mm; the horizontal thermal conductivity of the composite heat sink is 1800W/m·K, The thermal conductivity in the vertical direction is 700W/m·K.

The preparation method of the composite heat sink comprises the following steps:

Step 1. Select polyimide as the raw material, place it in a carbonization furnace for carbonization, the carbonization temperature is 1200°C, and the carbonization time is 7h; then move the carbonized material to the graphitization furnace for graphitization, and the graphitization temperature is The temperature is 2400°C, the graphitization time is 9 hours, and after taking it out, it is rolled to obtain graphite film 2;

Step 2: Cleaning the surface of the copper foil first, and then performing a punching process to obtain a mesh copper foil 1;

Step 3. Evenly spread the graphite film 2 obtained in Step 1 on the netted copper foil 1 obtained in Step 2, and then perform rolling in stages. The rolling pressure is 50kg/cm ³ , and the roll speed is 2.0m /min, the graphite-copper-foil composite heat sink is obtained.

Comparative example 4

The difference from Example 4 is that the composite heat sink in this comparative example uses an adhesive to compound the graphite film on both surfaces of the copper foil to form a graphite film-adhesive layer-copper foil-adhesive layer-graphite film structure Composite heat sink.

Example 5

As shown in Figure 2, a graphite-copper foil composite heat sink includes a mesh copper foil 1, and a graphite film 2 compounded on both sides of the mesh copper foil 1 by calendering technology, wherein the mesh copper foil 1 The thickness is 1mm, and the thickness of the single-layer graphite film 2 is 0.5mm; the porosity of the mesh copper foil 1 is 70%, and the aperture size is 0.1mm; the thermal conductivity of the composite heat sink is 2200W/m·K in the horizontal direction, and The directional thermal conductivity is 900W/m·K.

The preparation method of the composite heat sink comprises the following steps:

Step 1. Select polyimide as the raw material, place it in a carbonization furnace for carbonization, the carbonization temperature is 900°C, and the carbonization time is 6 hours; then move the carbonized material to the graphitization furnace for graphitization, and the graphitization temperature is The temperature is 2300°C, the graphitization time is 7 hours, and the graphite film 2 is obtained by calendering after taking it out;

Step 2: Cleaning the surface of the copper foil first, and then performing a punching process to obtain a mesh copper foil 1;

Step 3. Evenly spread the graphite film 2 obtained in Step 1 on the netted copper foil 1 obtained in Step 2, and then perform rolling in stages. The rolling pressure is 30kg/cm ³ , and the roll speed is 1.5m /min, the graphite-copper-foil composite heat sink is obtained.

Comparative example 5

The difference from Example 5 is that the composite heat sink in this comparative example uses an adhesive to compound the graphite film on both surfaces of the copper foil to form a graphite film-adhesive layer-copper foil-adhesive layer-graphite film structure Composite heat sink.

The thermal conductivity and mechanical properties of the composite cooling fins of Examples 1-5 and Comparative Examples 1-5 were tested respectively, and the test results are shown in Table 1.

The thermal conductivity and the mechanical performance test result of the composite cooling fin of table 1 embodiment and comparative example

As can be seen from the test results in Table 1, compared with the composite heat sink formed by bonding copper foil and graphite film with adhesive in Comparative Examples 1 to 5, the graphite-copper foil composite heat sink of the utility model has more excellent thermal conductivity. properties and mechanical properties. The reason is that the utility model adopts the calendering forming technology to make the graphite film 2 tightly compounded on the mesh copper foil 1. Since no adhesive is used, the interface thermal resistance is greatly reduced, and at the same time, the interlayer of the compound heat sink is effectively avoided. Degumming phenomenon, so that the composite heat sink has excellent mechanical properties and thermal conductivity and heat dissipation performance.

According to the disclosure and teaching of the above specification, those skilled in the art to which the present utility model belongs can also change and modify the above embodiment. Therefore, the utility model is not limited to the above specific implementation manners, and any obvious improvement, replacement or modification made by those skilled in the art on the basis of the utility model shall belong to the protection scope of the utility model. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present utility model.

Claims (8)

1. A graphite-copper foil composite heat sink is characterized in that: it comprises mesh copper foil, and a graphite film compounded on at least one side of mesh copper foil by calendering molding technology, and the porosity of said mesh copper foil is 40-80%, and the aperture size of the mesh copper foil is 0.002-2 mm. 2. The graphite-copper foil composite heat sink according to claim 1, characterized in that: the porosity of the mesh copper foil is 50-70%. 3. The graphite-copper-foil composite heat sink according to claim 1, characterized in that: the aperture size of the mesh-shaped copper foil is 0.01-1 mm. 4. The graphite-copper foil composite heat sink according to claim 1, characterized in that: the thermal conductivity of the heat sink in the horizontal direction is 1500-2500W/m·K, and the thermal conductivity in the vertical direction is 500-1000W/m·K . 5. The graphite-copper foil composite heat sink according to claim 1, characterized in that: the thickness of the mesh copper foil is 0.01-2mm. 6. The graphite-copper foil composite heat sink according to claim 1, characterized in that: the thickness of the graphite film is 0.01-1 mm. 7. The graphite-copper foil composite heat sink according to claim 1, characterized in that: the mesh shape of the mesh copper foil is circular, elliptical or polygonal. 8. The graphite-copper foil composite heat sink according to claim 1, wherein the graphite film is an artificial graphite film or a natural graphite film.