Patent Application
20190283365
The present invention relates to a laminate composite having multiple layers of a particular metal or metal alloy configured to have heat spreading capabilities.
Portable electronic devices (PEDs) utilize processors that generate a tremendous amount of heat. In order to dissipate the heat, PEDs can utilize a variety of materials that serve the dual purpose of spreading the heat as well as protecting the contents within the PEDs. Many PEDS today typically utilize stainless steel mono-metal for mechanical integrity and thermal heat dissipation. However, while the stainless steel provides good mechanical functionality, it has limited thermal performance. On the flip side, a copper mono-metal would have good thermal dispersion performance, but poor mechanical functionality. In addition, there is a need to control the direction of the heat dispersion within the material.
Therefore, there is a need for a material that has a combination of good mechanical functionality and thermal performance, as well as the ability to control the direction of the thermal dispersion.
A multiple layer laminate composite or system is described herein having improved thermal dispersion properties over known embodiments. The metallic laminate composite can include a first metallic layer having high heat dispersion characteristics and a thermal barrier material interlaid within the first metallic layer, the thermal barrier material preventing heat dispersion. In an aspect, the thermal barrier material is interlaid into the first metallic layer through bonding. In some instances, the barrier blocking material is harder than the first metallic layer. The thermal barrier material is interlard within the first metallic layer to prevent heat dispersion throughout a portion of the first metallic layer. In an aspect, the first metallic layer of the metallic laminate composite has a length and a width, and the thermal barrier material includes at least one linear component interlaid within and along the length of the first metallic layer. In some embodiments, there are two linear components that are interlaid within the first metallic layer to provide three distinct portions of the first metallic layer. The linear components can include wire.
In an aspect, the first metallic layer of the metallic laminate composite includes copper, copper alloy, aluminum, aluminum alloy, and the like. The thermal barrier material of the metallic laminate composite can include stainless steel and similar metals. In an aspect, the metallic laminate composite can include, along with the barrier material and first metallic layer, a second metallic layer bonded to the first metallic layer, the second layer having lesser heat dispersion characteristics. In some aspects, the second layer can come in contact with the thermal barrier material. In addition, the second metallic layer can be the same material as the thermal barrier material. In some aspects, the second metallic layer can include stainless steel addition, the metallic laminate composite can have three metallic layers, with two of the metallic layers having lesser heat dispersion characteristics and oriented on opposite sides of the first metallic layer, having the thermal barrier material interlaid within, the first metallic layer having high thermal dispersion characteristics. In other aspects, the metallic laminate composite can include three metallic layers, two metallic layers having high thermal dispersion properties and one having low thermal dispersion properties, with the high thermal dispersion layers sandwiching the low thermal dispersion layer, with both the outer high thermal dispersion property layers having thermal barrier material interlaid within.
These and other aspects of the invention can be realized from a reading and understanding of the detailed description and drawings.
In the following detailed description of the embodiments, reference is made to the accompanying drawings, which form a part hereof, and within which are shown by way of illustration specific embodiments by which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the invention. Electrical, mechanical, and structural changes may be made to the embodiments without departing from the spirit and scope of the present teachings. The following detailed description is therefore not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims and their equivalents.
A multiple layer laminate composite or system 10 with thermal dispersion is described herein. In an aspect, the multiple layer laminate composite 10 can include thermal barriers that assist with the direction of thermal dispersion. Some layers of the multiple layer laminate composite 10 exhibit low electrical resistivity properties (i.e., high heat dispersion properties) while others exhibit high electrical resistivity properties (i.e., low heat dispersion properties). In an aspect, the different metals selected for the multiple layer laminate composite 10, and their properties, can include those in
In an aspect, the laminate composite 10 is manufactured by a “cold” bonding process known in the art, such as described in U.S. Pat. No. 8,420,225, herein incorporated and relied upon by reference. In other aspects, the laminate composite 10 can be formed through other methods known in the art.
In an aspect, the metallic laminate composite 10 includes a first metallic layer 20 and thermal barriers 30 interlaid within the first metallic layer 20, as shown in
In an aspect, the thermal barrier 30 of thermal blocking material has a low heat dispersion characteristic (i.e., high electrical resistivity characteristics). The high electrical resistivity will be dependent on the material utilized as well as the cross-sectional area of the thermal blocking material 30. In an aspect, the thermal barrier material 30 can include, but is not limited to, stainless steel, and the like. In addition, the thermal barrier material 30 can have additional properties, including, but not limited to magnetic properties. In an aspect, the thermal barrier material 30 are linear components 32, 34. In exemplary aspects, the linear components 32, 34 are three dimensional linear components 32, 34. For example, the thermal barrier material 30 can be stainless steel wires 32, 34. In an aspect, the cross-section shape of the three dimensional linear component(s) 32, 34 varies based upon the needs of the composite 10. The cross-sectional shape of the three dimensional linear component can include, but is not limited to, circular, oval, rectangular, square, triangular, and the like. In other aspects, the thermal barrier material 30 can be molded to take different forms and shapes. For example, if the composite 10 needs to have an isolated circular portion within the first metallic layer 20, the thermal barrier material 30 can be made to form a circle before bonding with the first metallic layer 20.
In an aspect, the thermal barrier material 30 is a harder/denser material than the first metallic layer 20, which allows the thermal barrier material 30 to be interlaid or embedded into the first metallic layer 20 during bonding. In a preferred aspect, the thermal barrier material 30 is interlaid within the first metallic layer 20 only through bonding. That is, the first metallic layer 20 does not have to be cut or grooved to receive the thermal barrier material 30. By eliminating cutting or grooving of the first metallic layer 20, the manufacturing process is simplified, eliminating steps. However, in other embodiments, cutting or grooving the material may need to be done. The properties of the materials and requirements of the final laminate composite 10, including geometrical and physical, can determine how the thermal barrier material 30 is interlaid within first metallic layer 20.
For example,
As discussed above, the thermal barrier material 30 of the metallic laminate composite 10 is interlaid into the first metallic layer 20. The interla.y can occur through various means, including bonding, casting, and the like. However, there are advantages of interlaying the thermal barrier material 30 with the first metallic layer 20 through bonding, especially when the thermal barrier material 30 is harder than the first metallic layer 20 by eliminating the need to skive or form roll grooves from the first metallic layer 20 during manufacturing.
In an aspect, the metallic composite 10 can also include a second metallic layer 40. In such instances, the second metallic layer 40 differs from the first metallic layer 20 in properties. For example, as shown in
In an aspect, the multi-layer metallic composite is configured to have a small thickness aimed at use in PEDs. For example, the composite can be approximately 0.15-0.25 millimeters thick. However, the composite can have greater or smaller thicknesses, depending upon the end requirements for the composite. For example, the composite can range between 0.01 to 1 millimeter. The thickness of the other components can vary to arrive at this thickness. in an aspect, it is more desirable to have the metallic layer with high heat dispersion properties make up the majority of the multi-layer metallic composite. For example, the metallic layer with high heat dispersion properties can make up approximately 50 to 75 percent of the overall thickness of the composite after bonding. However, in other embodiments, the high heat dispersion material can make up 90 percent of the overall thickness. The thickness may vary depending upon the ultimate needs of the multilayer metallic laminate composite 10.
Further, regardless of the final product desired, or the number of layers created, each material can be tempered and cleaned to remove organics and metal oxides in order to achieve maximum bond strength.
An illustrative and non-limiting method of making a metallic composite according to an aspect of the invention is detailed below:
Step 1—Make a BPlt (i.e., a “B” Plae or materials before subsequent bonding) of Copper with Nickel or Stainless Steel wire inlays—(using pre-grooved Copper to help track the wire into location). The composite was made with 0.031″ Copper and 0.032″ diameter Nickel wire. This was bonded to 0.019″, (˜40% Red), . . . the Nickel wire flatten to Thickness×Width=˜0.0115″×0.042″.
Step 2—Next Clean & Bond this 0.019″/0.020″ thick center layer of Copper with the inlay Nickel wires between two layers of Stainless Steel.
Step 3—Bond to 0.010″/0.012″ . . . (if bonding to 0.010″ is possible intermediate rolling and annealing can be avoided).
Step 4—and on—Sinter . . . Trim . . . Anneal . . . Roll . . . Clean . . . SBL Level . . . Slit
Testing of Heat Dispersion with CLAD Ratios of SS—Cu—SS
Table II below shows a relative comparison of thermal spreading resistance for various clad ratios of stainless steel—copper—stainless steel and includes 100 percent copper and 100 percent stainless steel as relative baselines, The theoretical thermal spreading resistance values shown below were calculated assuming the following: the indicated clad ratio is shown with the percentage of the middle layer having a certain percentage by volume of the clad material (e.g., SS/Cu50/SS means the copper middle layer comprises 50% of the voluvolume of the clad material); the overall material thickness combination is 0.20 mm; the thermal conductivity of the stainless steel (300 Series)equals 16.3 W/m−K; the thermal conductivity of the pure copper is 401 W/m−K; the heat source dimensions equaled 25 mm,(1.0″)×25 mm,(1.0″), with a heat load of 2 W; heat spreader dimensions: 76 mm,(3.0″)×127 mm,(5.0″); orientation of the material was horizontal (i.e., the typical orientation of a PED when held in a user's hand), and the heat transfer coefficient was 5 (based on Natural Convection—Flat Plate). In the SS/Cu50/SS configuration, a specific composite of 25/50/25 was used, with the composite density being 0.303 lbs/in{circumflex over ( )}3, (0.0084 kg/cm{circumflex over ( )}3) with an overall thickness of 0.0082″, (0.208 mm). The mechanical properties of the clad material are a result of a final roll % reduction, with the typical tempers annealed, ¼ hard and ½ hard.
FIG, 10 illustrates the heat dispersion comparison shown between pure 300 Stainless Steel (top row) and a clad material having a SS/Cu50/SS distribution (bottom row) over 1200 seconds. As shown, heat dispersion efficiency (value of thermal spreading resistance (TSR)) in pure 400 Series Stainless Steel is much less than that of pure Copper, 100% 300 Stainless Steel=36.1° C./W vs Copper=1.93° C./W. It can be estimated that pure Copper is ˜18.7 times better than pure 300 Series Stainless Steel when spreading heat. Therefore, combining different volumes of Copper and Stainless Steel as a Clad Laminate at different volume ratios will result in with various proportional heat dispersion efficiencies or TSRs as indicated in Table II above.
Having thus described exemplary embodiments of a method to produce metallic composite material, it should be noted by those skilled in the art that the within disclosures are exemplary only and that various other alternatives, adaptations, and modifications may be made within the scope of this disclosure, :Accordingly, the invention is not limited to the specific embodiments as illustrated herein, but is only limited by the following claims.
| Number | Date | Country | |
|---|---|---|---|
| 62644178 | Mar 2018 | US |
