With the speed of the remove and renovation for electronic articles, the incessantly increase managing need of heat transmission for high-integration, high-power, mini-electronic device, my company fetches the whole new technology resolvent on heat transmission for electronic article,that is the new resolvent on heat transmission for graphite material .

This bran-new insolvent scheme for flake graphite is high-efficiency for dropping away the heat, small space, light weight，heat transmission equably along two directions, purge the “hot dot” area, the screen heat origin and discreteness improve the capacity of the consumptive electronic article.

It is used widely on tip-top, PDF-numeral vidicon, portable projector, mobile phone and so on the heat spread material in consumptive electronic articles.

The typical calorifics management system includes the external cooling device, radiator, thermal section. The important function of heat sink is creating the effective max-surface area, the heat on the surface is transferred and taken away by the outer cooling media .The graphite heat sink transfers the heat effectively by distributing the heat on the planar plane, ensuring the discreteness work under the enduring temperature.

The implementary scheme for the graphite heat spread material technology

We can optimize the heat conductivity by controlling the density, thickness, purity of the graphite material effectively. The experiment shows that enlarging the density constantly can enhance the intensity and conductive heat capacity, however the resistivity reduces continually. We can optimize according to the clients’ request.

Nowadays, the thermal conductivity of developed graphite heat sink has been up to near 2000W/mK ,exceeding far the best international record（750 W/MK），and design the collate table of thermal conductivity under different densities ,owning strong operating action.

Now, some structural formats that is included by graphite, metal, plastic and other materials have been made ,it has over 40 sorts of different thermal conductivities for satisfying more design needs.

The graphite material can be incised as the clients’ request. What’s more, it can with adhesive on the surface, is fixed conveniently and keep the higher thermal conductivity, also is perforated and made into different thicknesses.

Common specs: the discreteness is made as need, supplying the range 0.075mm-2.0mm thickness, shape and size. The surface is compounded with plastic, wet-glue, aluminum plate, copper board and so on metal materials.

For instance: graphite material and metal foil can form complicated three-dimensional solid design. Aluminum foil can keep the outer shape, meanwhile enhance the flexibility, the weight is lighter 80% than copper, it’s also lighter 30% than aluminum, and enhances its electronic conductivity.

The compound of graphite film and aluminum can improve the flexural strength, at the same time, seal the graphite sheet around with the machining technology by pressing with aluminum to prevent the graphite powder from affecting the appearance, the heat MPU creates can spread to graphite film, even the back of key board and outline border to outer, and undergird the effect of transmitting heat.

Advantage for graphite heat sink：

a. high thermal conductivity low thermal impedance

The thermal conductivity of graphite heat sink is twice than that of aluminum, the same as copper, but lighter than copper. The nonidentity of thermal conductivity which material owns per se and consistency of natural graphite give new cooling scheme the unique advantages that other common materials can’t have.

As the graphite conducts heat, it can flow as determinate direction, under such identity, graphite can know from the common windy cooling grain of a material copper, aluminum, because these two metals don’t own such identity, it isn’t used to control the direction that heat conducts. So the product is made, using the graphite thermal spread technology can conduct heat continually as the need.

Such unique material can spread the heat along two directions equably, eliminate “hot dot”, make the heat origin and discreteness screen, the thermal conductivity on level is up to 1500W/mK， that on vertical plane is in 6-60 W/MK. The common heat sink material, for example, copper and aluminum, they all conduct heat along each direction, but thanks to the higher tangent thermal impedance, they can’t transmit the heat from the discreteness effectively. The low electrical receptivity and minus C.T.E of graphite on the level direction reduce the graphite thermal impedance.

The flat extent, tight press, thickness of material will form the effect for tangent thermal impedance; however, the graphite heat sink has great exterior touch, and can adhibit smoothly on any plane or flexural surface.
b. light weight: lighter 80% than copper, lighter 30% than aluminum

When the space of cooling scheme that the product adopts is limited, meanwhile under the weight as important element, the graphite heat sink is an ideal choice. On many conditions, comparing with the other heat transmitting management resolvent, on some applications, it replaces the traditional fan/radiator; hence it can reduce the 50% whole weight from the heat transmitting discreteness. It can decrease the need e.g. Fan, radiator or air-cooled tube, so that debase the cost and the weight

With the development of micro-electronics technology, the smaller the work discreteness’ size and volume, the higher the work speed and efficiency, the larger the quantity of releasing heat ,must adopt advanced heat transmitted technology and excellent capability heat sink to take away the heat, ensure the effective work,

The operating temperature of graphite sheet is up to 500℃,under -40℃,it can be used normally.

Product application

The material needs to be handtailored ,used electronic consumptive area, for instance tip-top, PDF-numeral vidicon, portable projector, mobile phone as well as personal assistant device LCD、PDP、DVD and so on. On the development of portable electronic product towards the high density encapsulation and multifunctional direction, graphite heat and electricity conducted material is undoubted the best new-style heat sink material, having wider market prospect.

Additional:

1. The technology field requested: the application field of heat and electricity conducted for graphite heat sink material in the electronic products.

2. The background technology: No the related mature technology and product by researched in-out country at present.