Thermal pad, circuit board assembly and electronic device

Abstract

The present application relates to the technical field of thermal conduction. Disclosed in the embodiments of the present application are a thermal pad, a circuit board assembly and an electronic device, which solve the problem of high thermal interface loss of graphene thermal pads caused by edge-sealing structures in the prior art. The thermal pad comprises a thermally conductive layer, a resilient perimeter barrier and two edge-sealing layers; the thermal pad may be multiple layers of graphene films stacked in sequence; the thermal pad comprises a first surface and a second surface which are opposite to each other; the resilient perimeter barrier is arranged around the outer periphery of the thermally conductive layer; additionally, the resilient perimeter barrier has a first end face and a second end face which are opposite to each other; the first end face and the first surface are located on a same side; the second end face and the second surface are located on a same side; one of the edge-sealing layers is circumferentially stacked at the edge of the first surface of the thermally conductive layer and the first end face of the resilient perimeter barrier; the other edge-sealing layer is circumferentially stacked at the edge of the second surface of the thermally conductive layer and the second end face of the resilient perimeter barrier; additionally, the two edge-sealing layers are both connected to the thermally conductive layer and the resilient perimeter barrier.

Description

A heat-conducting pad, a circuit board assembly and an electronic device

[0001] The present application claims priority to the Chinese patent application No. 202421251443.3, filed on June 03, 2024, and entitled "A heat-conducting pad, a circuit board assembly and an electronic device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of heat conduction, in particular to a heat-conducting pad, a circuit board assembly and an electronic device. BACKGROUND

[0003] In order to improve the heat exchange efficiency between the chip and the outside, a heat-conducting pad is arranged between the chip and the heat sink to quickly conduct the heat of the chip to the heat sink for heat dissipation. Among them, the graphene heat-conducting pad has high thermal conductivity and can be used for chip heat dissipation. However, the strength of the graphene heat-conducting pad in the thickness direction is significantly higher than the cohesive strength in the width direction, which causes the graphene heat-conducting pad to easily crack or fall off at the side edges during use. The graphene powder has good electrical conductivity and falls on the chip pin, which may cause the risk of short circuit of the chip. Therefore, the application of the graphene heat-conducting pad is limited.

[0004] In order to reduce the risk of cracking and falling of the graphene heat-conducting pad during use, a layer of adhesive tape or structural adhesive can be attached around the graphene heat-conducting pad for edge covering. However, this edge covering structure will occupy a large heat-conducting area on the surface of the graphene heat-conducting pad, resulting in a large loss of the heat conduction interface. SUMMARY

[0005] The present application provides a heat-conducting pad, a circuit board assembly and an electronic device, which solves the problem of large loss of the heat conduction interface of the graphene heat-conducting pad caused by the existing edge covering structure.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a heat-conducting pad. The heat-conducting pad includes a heat-conducting layer, a resilient enclosure and two edge sealing layers. The heat-conducting pad can be a plurality of graphene films stacked in sequence. The heat-conducting pad has a first surface and a second surface opposite to each other. The resilient enclosure is arranged around the outer periphery of the heat-conducting layer. The resilient enclosure has a first end surface and a second end surface opposite to each other, both of which are annular surfaces. The first end surface is located on the same side as the first surface, and the second end surface is located on the same side as the second surface. One edge sealing layer is circumferentially stacked at the edge of the first surface of the heat-conducting layer and the first end surface of the resilient enclosure. The other edge sealing layer is circumferentially stacked at the edge of the second surface of the heat-conducting layer and the second end surface of the resilient enclosure. Both of the two edge sealing layers are connected with the heat-conducting layer and the resilient enclosure.

[0008] Compared with the prior art, the edge sealing structure of the heat-conducting pad in the embodiments of the present application includes a resilient enclosure and two layers of edge sealing layers. The two layers of edge sealing layers can cover part of the end surface of the resilient enclosure as an edge sealing support structure, thereby reducing the width of the two layers of edge sealing layers that need to be covered on the heat-conducting layer. That is, a narrower edge sealing layer (such as a width of less than 2 mm) can be used. The coverage area ratio of the two layers of edge sealing layers on the heat-conducting layer is low, the heat conduction interface loss is small, and the overall compression stress on the heat-conducting layer is also smaller. Moreover, the edge sealing structure in the embodiments of the present application can also reduce the risk of cracking and powder falling of the multi-layer stacked graphene heat-conducting film during use.

[0009] Therefore, in some embodiments of the present application, the width of the edge sealing layer covering the heat-conducting layer is 0.1-0.5 mm, which ensures that the area of the edge sealing layer covering the heat-conducting pad is relatively low in the total surface area of the heat-conducting pad, the heat conduction interface loss is small, and the overall compression stress on the heat-conducting pad is also smaller.

[0010] Based on the structure of the heat-conducting pad, in some embodiments of the present application, the edge sealing layer includes a double-sided adhesive layer, which is bonded with the heat-conducting layer and the resilient enclosure. At the same time, when the heat-conducting pad is applied in the field of chips, the double-sided adhesive layer in the double-layer edge sealing layer can be bonded with the chip and the heat sink. The heat-conducting pad, the heat sink and the chip are fixed with each other to prevent mutual misalignment or slipping during transportation.

[0011] Moreover, in some embodiments, the heat-conducting pad can further include an adhesive layer, which is wrapped around the outer periphery of the heat-conducting layer. The adhesive layer bonds the resilient enclosure with the outer side wall of the heat-conducting layer. Thus, the resilient enclosure and the heat-conducting layer are further fixed.

[0012] In addition, in order to be suitable for more scenarios, in some examples of the present application, the edge sealing layer further includes a substrate layer, which is bonded to the side of the double-sided adhesive layer away from the heat-conducting layer or the resilient enclosure.

[0013] For example, the edge sealing layer located close to the heat sink only includes a double-sided adhesive layer, which is bonded with the resilient enclosure, the heat-conducting layer and the heat sink. The edge sealing layer located close to the chip side can include a substrate layer and a double-sided adhesive layer, and the double-sided adhesive layer of the edge sealing layer is bonded with the resilient enclosure, the heat-conducting layer and one side surface of the substrate layer. The other side surface of the substrate layer is attached to the chip. In the transportation process or repair, the heat sink in this example can be easily removed from the chip, not only avoiding the misalignment of the chip with the heat-conducting layer during transportation, but also facilitating maintenance operations.

[0014] Based on the structure of the edge sealing layer, in some embodiments of the present application, the storage modulus of the double-sided adhesive layer is 0.001-0.01 MPa at room temperature. When the thermal conductive pad is assembled with the heat sink and the chip, the thermal conductive pad will be extruded. The thermal conductive pad with the above physical parameters can be combined with the surface of the thermal conductive layer, the resilient barrier, the heat sink and the chip under pressure, and the bonding force is greater than 0.1 MPa. Moreover, the compression stress of the double-sided adhesive layer after curing is lower than that of the graphene thermal conductive layer, so that the cohesive strength of the edge sealing layer is similar to that of the graphene thermal conductive layer. Thus, stress concentration is not easy to occur at the position where the graphene thermal conductive layer is attached to the edge sealing layer, i.e. the edge of the graphene thermal conductive layer, avoiding the problem of bulging at the edge of the graphene thermal conductive layer. Moreover, there is no risk of cracking at the junction of the edge sealing area and the non-edge sealing area of the graphene thermal conductive layer. Based on the above parameters, in some embodiments of the present application, the material of the double-sided adhesive layer includes any one or a combination of acrylic resin, epoxy resin and polyurethane, which has the advantages of good corrosion resistance and good wear resistance.

[0015] For the above substrate layer, in some embodiments of the present application, the Young's modulus of the substrate layer is greater than 10 MPa at room temperature. The substrate layer can also be combined with the surface of the double-sided adhesive layer under pressure, and the bonding force is greater than 0.1 MPa, so that the cohesive strength of the edge sealing layer is similar to that of the graphene thermal conductive layer, to avoid the problem of bulging or cracking at the edge of the graphene thermal conductive layer. Based on the above parameters, in some embodiments of the present application, the material of the substrate layer includes any one or a combination of polymeric film, fabric layer and metal foil. These materials have the advantages of high temperature stability, far greater toughness than graphene sheet, and not easy to deform after being pressed.

[0016] For the above resilient barrier, in some embodiments of the present application, the resilient barrier includes any one or a combination of polymeric film, fabric layer and metal foil. The resilient barrier made of the above materials has good elasticity.

[0017] In some other embodiments of the present application, the above resilient barrier is a polymeric foam material with a compression stress of 10-50 Psi at a 50% compression amount. The compression stress of the polymeric foam is relatively low, and it has the advantages of low cost and light texture. Based on this, in some embodiments of the present application, the above polymeric foam material includes any one or a combination of polyester, polyolefin, acrylic resin, epoxy resin and polyurethane.

[0018] In order to adapt to various application scenarios, in some embodiments of the present application, the thickness of the above resilient barrier is equal to the thickness of the thermal conductive layer, which can be applied to a thermal conductive layer with a thickness of 0.3 mm or less, making the process of the resilient barrier more convenient.

[0019] In some embodiments of the present application, the thickness of the resilient enclosure is less than the thickness of the heat-conducting layer, which can be applied to the scenario where the thickness of the heat-conducting layer is greater than 0.3 mm, so that the resilient enclosure has less impact on the heat-conducting pad.

[0020] In a second aspect, the embodiments of the present application further include a circuit board assembly, which comprises a circuit board, a chip, a heat sink and the heat-conducting pad described in the above embodiments. The chip is arranged on the circuit board. The heat sink is arranged on the chip. The heat-conducting pad is arranged between the heat sink and the chip. Since the heat-conducting pad in the circuit board assembly of the embodiments of the present application has the same structure as the heat-conducting pad described in the above embodiments, both can solve the same technical problems and obtain the same technical effects, which will not be described here.

[0021] In a third aspect, the embodiments of the present application further include an electronic device, which comprises a shell and the circuit board assembly described in the above embodiments. The circuit board assembly is arranged in the shell. Since the circuit board assembly in the electronic device of the embodiments of the present application has the same structure as the circuit board assembly described in the above embodiments, both can solve the same technical problems and obtain the same technical effects, which will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be described below.

[0023] FIG. 1 is a structural schematic diagram of the electronic device of the embodiments of the present application as a notebook computer;

[0024] FIG. 2 is a structural schematic diagram of the circuit board assembly of the embodiments of the present application;

[0025] FIG. 3 is an assembly structural schematic diagram of the mainboard, the heat sink and the heat-conducting pad in the circuit board assembly of the embodiments of the present application;

[0026] FIG. 4(a), (b) and (c) are structural schematic diagrams of the first heat-conducting pad with the adhesive tape layer or the structural adhesive layer in the related art in the uncompressed state, after being compressed to generate the first deformation and after being compressed to generate the second deformation, respectively;

[0027] FIG. 5(a) and (b) are structural schematic diagrams of the second heat-conducting pad with the adhesive tape layer or the structural adhesive layer in the related art in the uncompressed state and after being compressed to generate the deformation, respectively;

[0028] FIG. 6 is an assembly structural schematic diagram of the heat-conducting pad, the heat sink and the chip in the embodiments of the present application;

[0029] FIG. 7 is a top view of the heat-conducting layer and the resilient enclosure in the heat-conducting pad of the embodiments of the present application;

[0030] Fig. 8 is a schematic view of a structure of a heat-conducting pad according to an embodiment of the present application;

[0031] Fig. 9 is a schematic view of a structure of a heat-conducting pad according to another embodiment of the present application;

[0032] Fig. 10 is a schematic view of a structure of a heat-conducting pad according to another embodiment of the present application;

[0033] Fig. 11 is a schematic view of a structure of a heat-conducting pad according to another embodiment of the present application;

[0034] Fig. 12 is a schematic view of an assembly structure of a heat-conducting pad, a heat sink and a chip with a cover according to an embodiment of the present application;

[0035] Fig. 13 is a schematic view of a structure of a heat-conducting pad according to an embodiment of the present application, in which the thickness of the resilient enclosure is less than the thickness of the heat-conducting layer.

[0036] Fig. 13 is a schematic view of a structure of a heat-conducting pad according to an embodiment of the present application, in which the thickness of the resilient enclosure is less than the thickness of the heat-conducting layer. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings.

[0038] Hereinafter, the terms "first", "second", and the like are only used for the purpose of description and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second", and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0039] In addition, in the present application, the orientation terms such as "upper", "lower", "left", "right", "horizontal" and "vertical" are defined with respect to the orientation of the components shown in the drawings, and it should be understood that these directional terms are relative concepts, which are used for relative description and clarification, and they can be changed accordingly according to the change of the orientation of the components placed in the drawings.

[0040] In this application, unless otherwise expressly specified and limited, the term "connection" should be interpreted broadly, for example, "connection" can refer to mechanical structure, physical structure connection. It can be fixed connection, or detachable connection, or integral; it can be direct connection, or indirect connection through intermediate medium. It can also be understood as physical contact and electrical conduction of components, or as the form of connection between different components in circuit structure through PCB copper foil or wire, etc. entity line that can transmit electrical signals.

[0041] The present application provides an electronic device, which can include a mobile phone, a tablet personal computer, a laptop computer, a personal digital assistant (PDA), a camera, a personal computer, a notebook computer, a vehicle-mounted device, a wearable device, augmented reality (AR) glasses, an AR helmet, virtual reality (VR) glasses, a VR helmet, a router, a server, or a switch, etc. The specific form of the electronic device is not specially limited in the embodiments of the present application. For the convenience of description, the electronic device is taken as a notebook computer as shown in FIG. 1 for example.

[0042] Please refer to FIG. 1 and FIG. 2, FIG. 1 is a perspective view of the electronic device provided by some embodiments of the present application as a notebook computer. FIG. 2 is a structural schematic diagram of a circuit board assembly in the electronic device of the embodiments of the present application. As described above, the notebook computer 1000 can include a display screen 100, a body shell 200, a keyboard 300, a circuit board assembly 400, a battery, etc.

[0043] Among them, the display screen 100 and the body shell 200 can be connected in a rotating manner (such as hinged). The keyboard 300 can be embedded on the body shell 200. The circuit board assembly 400 and the battery are arranged in the body shell 200. As shown in FIG. 2 and FIG. 3, the circuit board assembly 400 includes a mainboard 10 (which can be a printed circuit board), and a chip 40, a heat sink 20, a hard disk, a memory, various interfaces, expansion slots, a sound card, a power supply, etc. various electronic devices and other auxiliary devices such as a heat-conducting pad 30 arranged on the mainboard. As shown in FIG. 3, the heat sink 20 can be arranged on the high-power chip through the heat-conducting pad 30.

[0044] It can be understood that FIG. 1 and FIG. 2 only schematically show some components included in the electronic device 1000, and the actual shape, actual size, actual position and actual structure of these components are not limited by FIG. 1 and FIG. 2.

[0045] The graphene thermal conductive pad has high thermal conductivity. If the thermal conductive pad 30 is a graphene thermal conductive pad. The graphene thermal conductive pad has a strength in the thickness direction (the Z-axis direction in FIG. 3) that is significantly higher than the cohesive strength in the width direction (the X-axis direction in FIG. 3), which causes the graphene thermal conductive pad to easily crack or fall off at the side edges during use. The graphene powder has good electrical conductivity and falls onto the chip pins, which can cause the risk of short circuit of the chip. Therefore, the application of the graphene thermal conductive pad is limited.

[0046] To reduce the risk of cracking and falling off of the graphene thermal conductive pad during use, the graphene thermal conductive pad can be wrapped with a tape layer or a structural adhesive layer 010 around the periphery as shown in FIG. 4 or FIG. 5. However, this wrapping structure occupies a large thermal conductive area on the surface of the graphene thermal conductive pad, which reduces the effective thermal conductive area of the thermal conductive pad 30, resulting in a large loss of the heat transfer interface. Moreover, when the graphene thermal conductive pad is installed under pressure (such as 40% compression in the thickness direction), the wrapping effect is affected by the deformation of the tape layer or the structural adhesive layer 010 from the surface of the graphene thermal conductive pad.

[0047] For example, the graphene thermal conductive pad and the tape layer or the structural adhesive layer 010 in (a) of FIG. 4 can be compressed by 40% in the thickness direction after being pressed, as shown in (b) of FIG. 4. The tape layer or the structural adhesive layer 010 changes from a horizontally placed U shape to a horizontally placed circular arc shape, and the outer side wall of the graphene thermal conductive pad is separated from the tape layer or the structural adhesive layer 010. Alternatively, the graphene thermal conductive pad can be compressed by 40% in the thickness direction after being pressed, as shown in (c) of FIG. 4. The tape layer or the structural adhesive layer 010 changes from a horizontally placed U shape to a horizontally placed U shape with a triangular bottom, and the outer side wall of the graphene thermal conductive pad is also separated from the tape layer or the structural adhesive layer 010. The graphene thermal conductive pad and the tape layer or the structural adhesive layer 010 in (a) of FIG. 5 can be compressed by 40% in the thickness direction after being pressed, as shown in (b) of FIG. 5. The tape layer or the structural adhesive layer 010 deforms, so that the outer side wall of the graphene thermal conductive pad is also separated from the tape layer or the structural adhesive layer 010.

[0048] To solve the above problems, an improved thermal conductive pad 30 is provided in the embodiments of the present application. Referring to FIGS. 6 and 7, the thermal conductive pad 30 includes a thermal conductive layer 1, a resilient enclosing wall 2, and two edge sealing layers 3.

[0049] The thermal conductive layer 1 can be a plurality of graphene films stacked in sequence. For example, the graphene thermal conductive films can be formed by layer-by-layer stacking and adhesive bonding. Then, the graphene thermal conductive films are cut into the required shape, so that the graphene thermal conductive films are arranged in the thickness direction (i.e., the heat transfer direction). Thus, the required thermal conductive layer 1 is obtained. Moreover, the thermal conductive layer 1 has opposite first and second surfaces 11 and 12.

[0050] The resilient containment 2 is arranged around the outer periphery of the heat-conducting layer 1. The resilient containment 2 has opposite first and second end faces 21 and 22. The first and second end faces 21 and 22 are annular faces. The first end face 21 is on the same side as the first surface 11 of the heat-conducting layer 1. The second end face 22 is on the same side as the second surface 12 of the heat-conducting layer 1.

[0051] In the two edge sealing layers 3 (edge sealing layer 3a and edge sealing layer 3b), the edge sealing layer 3a is arranged around the edge of the first surface 11 of the heat-conducting layer 1 and the first end face 21 of the resilient containment 2. The edge sealing layer 3b is arranged around the edge of the second surface 12 of the heat-conducting layer 1 and the second end face 22 of the resilient containment 2. Both edge sealing layers 3 are connected to the heat-conducting layer 1 and the resilient containment 2.

[0052] Compared with the heat-conducting pad 30 shown in FIGS. 4 and 5, the edge sealing structure of the heat-conducting pad 30 of the embodiment includes the resilient containment 2 and the two edge sealing layers 3. The two edge sealing layers 3 can cover part of the end face of the resilient containment 2 as an edge sealing support structure, reducing the width of the two edge sealing layers 3 that need to be covered on the heat-conducting layer 1. That is, a narrower edge sealing layer 3 can be used. The coverage area of the two edge sealing layers 3 on the heat-conducting layer 1 is small, the heat conduction interface loss is small, and the overall compression stress on the heat-conducting layer 1 is also small. Moreover, the heat-conducting pad 30 of the embodiment can not only reduce the risk of cracking and powdering of the multi-layer stacked graphene heat-conducting film during use, but also has higher edge protection and tensile strength of the heat-conducting pad 30, and the edge sealing layer 3 will not be separated from the heat-conducting layer 1 when the heat-conducting pad 30 is installed under pressure (40% compression in the thickness direction).

[0053] Based on this, in some embodiments of the present application, as shown in FIG. 8, the width W1 of the edge sealing layer 3 covering the heat-conducting layer 1 is 0.1-0.5 mm, which ensures that the area of the edge sealing layer 3 covering the heat-conducting pad 30 is small, the heat conduction interface loss is small, and the overall compression stress on the heat-conducting pad 30 is also small. Accordingly, the total width W0 of the edge sealing layer 3 is 0.5-2 mm.

[0054] In addition, the bonding surface of the graphene heat-conducting film itself has no adhesion, and the friction at the contact interface with the electronic device (such as the chip 40) is small, which causes the graphene heat-conducting film to be prone to misalignment or displacement in actual operation. In order to avoid the above problems, in some embodiments of the present application, the above edge sealing layer 3a includes a double-sided adhesive layer 31 as shown in FIG. 9, one side surface of the double-sided adhesive layer 31 is bonded with the heat-conducting layer 1, and the other side surface of the double-sided adhesive layer 31 is bonded with the heat sink 20. Alternatively, the above edge sealing layer 3b includes a double-sided adhesive layer 31 as shown in FIG. 9, one side surface of the double-sided adhesive layer 31 is bonded with the edge sealing layer 3, and the other side surface of the double-sided adhesive layer 31 is bonded with the chip 40. The double-sided adhesive layers 31 in the two edge sealing layers 3 can be bonded with the chip 40 and the heat sink 20, respectively. The heat-conducting pad 30 is fixed with the heat sink 20 and the chip 40, which can prevent mutual misalignment or sliding during transportation.

[0055] In addition, the thickness of the double-sided adhesive layer 31 can be 5-50 um to ensure the fixing effect of the heat sink 20 and the chip 40. In some embodiments of the present application, the thickness of the double-sided adhesive layer 31 is 20-40 um.

[0056] It should be noted that the above heat-conducting pad 30 can also include an adhesive layer 4 as shown in FIG. 10, which is wrapped around the outer periphery of the heat-conducting layer 1. In addition, the adhesive layer 4 bonds the resilient containment 2 with the outer side wall of the heat-conducting layer 1. Thus, the resilient containment 2 and the heat-conducting layer 1 are further fixed. Specifically, the material of the adhesive layer 4 includes any one or both of acrylic resin and polyurethane.

[0057] However, considering the convenience of removing the chip 40 during repair and the ease of removing the heat-conducting pad 30 during disassembly and repair of the heat sink 20, in some examples of the present application, the above edge sealing layer 3 further includes a substrate layer 32 as shown in FIG. 11, which is located on the side of the double-sided adhesive layer 31 away from the heat-conducting layer 1 or the resilient containment 2.

[0058] For example, continuing to refer to FIG. 11, the edge sealing layer 3a located close to the heat sink 20 only includes the double-sided adhesive layer 31, which is bonded with the resilient containment 2, the heat-conducting layer 1 and the heat sink 20. The edge sealing layer 3b located close to the chip 40 can include the substrate layer 32 and the double-sided adhesive layer 31, which is bonded with the resilient containment 2, the heat-conducting layer 1 and one side surface of the substrate layer 32. The other side surface of the substrate layer 32 is attached to the chip 40. The circuit board assembly 400 of this example can conveniently remove the heat sink 20 from the chip 40 during transportation or repair, which not only avoids misalignment of the chip 40 with the heat-conducting layer 1 during transportation, but also facilitates maintenance operations.

[0059] Since the cohesive strength of the area on the heat conduction layer 1 covered by the edge sealing layer 3 is much greater than that of the area not covered by the edge sealing layer, when the graphene heat conduction pad is compressed in the thickness direction, the area on the heat conduction layer 1 covered by the edge sealing layer 3 is prone to stress concentration. At the same time, the connection between the heat conduction layer 1 and the edge sealing layer 3 inevitably produces a bulge. In particular, there is a risk of cracking at the joint between the area on the heat conduction layer 1 covered by the edge sealing layer 3 and the uncovered area.

[0060] To avoid the above problems, in some embodiments of the present application, the storage modulus of the double-sided adhesive layer 31 described above is 0.001-0.01 MPa at room temperature. When the heat conduction pad 30 is assembled with the heat sink 20 and the chip 40, the heat conduction pad 30 will be subjected to compression. Under the compression condition, the double-sided adhesive layer 31 with the above parameters can have a surface bonding force with the heat conduction layer 1, the resilient containment 2, the heat sink 20, and the chip 40 that is greater than 0.1 MPa. Moreover, the compression stress of the double-sided adhesive layer 31 after curing is lower than that of the graphene heat conduction layer 1, so that the cohesive strength of the edge sealing layer 3 is similar to that of the graphene heat conduction layer 1. Thus, the position where the graphene heat conduction layer 1 and the edge sealing layer 3 are attached, i.e., the edge of the graphene heat conduction layer 1, is not prone to stress concentration, avoiding the problem of bulging at the edge of the graphene heat conduction layer 1. Moreover, the risk of cracking at the joint between the edge sealing area and the non-edge sealing area of the graphene heat conduction layer 1 is reduced.

[0061] Based on the above parameters, in some embodiments of the present application, the material of the double-sided adhesive layer 31 with a storage modulus of 0.001-0.01 MPa at room temperature can include any one or a combination of several of acrylic resin, epoxy resin, and polyurethane, which has the advantages of good corrosion resistance and good wear resistance.

[0062] For the edge sealing layer 3 with a substrate layer 32, in some embodiments of the present application, the Young's modulus of the substrate layer 32 is greater than 10 MPa at room temperature. The substrate layer 32 can also have a surface bonding force with the double-sided adhesive layer 31 that is greater than 0.1 MPa under compression, so that the cohesive strength of the edge sealing layer 3 is similar to that of the graphene heat conduction layer 1, to avoid the problem of bulging or cracking at the edge of the graphene heat conduction layer 1.

[0063] Based on the above parameters, in some embodiments of the present application, the material of the substrate layer 32 includes any one or a combination of several of a polymer film, a fabric layer, and a metal foil. These materials have the advantages of high temperature stability, much greater toughness than graphene sheet, and not easy to deform after compression.

[0064] The above is mainly described for the edge sealing layer 3. For the above resilient barrier 2, in some embodiments of the present application, the resilient barrier 2 is made of any one or any combination of the following materials: polymer film, fabric layer, metal foil. The resilient barrier 2 made of these materials has good elasticity.

[0065] In some other embodiments of the present application, the resilient barrier 2 is made of a polymer foam material with a compressive stress of 10-50 Psi (pounds per square inch) at 50% compression. The polymer foam has a lower compressive stress at the same thickness, and has the advantages of low cost and light weight. For example, the polymer foam material includes any one or any combination of polyester, polyolefin, acrylic resin, epoxy resin and polyurethane.

[0066] It should be noted that the heat-conducting pad 30 with the above structure and material can be used not only for heat dissipation of a bare die, but also for a packaged die. That is, the packaged die has a lid 401 as shown in FIG. 12.

[0067] In addition, for the heat-conducting layer 1 with different thicknesses, the resilient barrier 2 can have different thicknesses. In some embodiments of the present application, the thickness T1 of the resilient barrier 2 is equal to the thickness T2 of the heat-conducting layer 1, which can be used for a heat-conducting layer 1 with a small thickness, such as a heat-conducting layer 1 with a thickness T2 of 0.3 mm or less, so that the resilient barrier 2 is easy to process.

[0068] In some other embodiments of the present application, as shown in FIG. 13, the thickness T1 of the resilient barrier 2 is less than the thickness T2 of the heat-conducting layer 1, which can be used for a heat-conducting layer 1 with a large thickness, such as a heat-conducting layer 1 with a thickness T2 of more than 0.3 mm, so that the resilient barrier 2 has less effect on the heat-conducting pad 30. For example, the thickness T1 of the resilient barrier 2 is 40-60% of the thickness T2 of the heat-conducting layer 1.

[0069] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A heat-conductive pad, characterized by, The heat-conducting pad comprises: a heat-conducting layer having opposite first and second surfaces; a resiliently flexible surrounding layer surrounding the heat-conducting layer; the resiliently flexible surrounding layer has opposite first and second end surfaces; the first end surface is on the same side as the first surface, and the second end surface is on the same side as the second surface; two edge sealing layers, one of which is circumferentially arranged on the edge of the first surface of the heat-conducting layer and the first end surface of the resiliently flexible surrounding layer, and the other of which is arranged on the edge of the second surface of the heat-conducting layer and the second end surface of the resiliently flexible surrounding layer, both of which are connected to the heat-conducting layer and the resiliently flexible surrounding layer.

2. The thermally conductive mat of claim 1, wherein, The edge sealing layer comprises a double-sided adhesive layer which is bonded to the heat-conducting layer and the resiliently flexible surrounding layer.

3. The thermal pad of claim 2, wherein, The storage modulus of the double-sided adhesive layer is 0.001-0.01 MPa at room temperature.

4. The thermally conductive mat of claim 2 or 3, wherein, The material of the double-sided adhesive layer comprises any one or a combination of acrylic resin, epoxy resin, and polyurethane.

5. The thermally conductive mat of any one of claims 2-4, wherein, The edge sealing layer further comprises a substrate layer which is bonded to the double-sided adhesive layer on the side surface away from the heat-conducting layer or the resiliently flexible surrounding layer.

6. The thermally conductive mat of claim 5, wherein, The Young's modulus of the substrate layer is greater than 10 MPa at room temperature.

7. The thermally conductive mat of claim 5 or 6, wherein, The material of the substrate layer comprises any one or a combination of a polymer film, a fabric layer, and a metal foil.

8. The thermally conductive mat of any one of claims 1-7, wherein, The resiliently flexible surrounding layer comprises any one or a combination of a polymer film, a fabric layer, and a metal foil. Alternatively, the resiliently flexible surrounding layer is a polymer foam material with a compressive stress of 10-50 Psi at a 50% compression amount.

9. The thermally conductive mat of claim 8, wherein, The polymer foam material comprises any one or a combination of polyester, polyolefin, acrylic resin, epoxy resin, and polyurethane.

10. The thermally conductive mat of any one of claims 1-9, wherein, The edge sealing layer covers the heat-conducting layer with a width of 0.1-0.5 mm.

11. The thermally conductive mat of any one of claims 1-10, wherein, The heat-conducting pad further comprises: an adhesive layer which is arranged around the outer periphery of the heat-conducting layer and bonds the resiliently flexible surrounding layer to the outer side wall of the heat-conducting layer.

12. The thermally conductive mat of any one of claims 1-11, wherein, The thickness of the resiliently flexible surrounding layer is equal to or less than the thickness of the heat-conducting layer.

13. The thermally conductive mat of any one of claims 1-12, wherein, The heat-conducting layer comprises a plurality of graphene films stacked in sequence.

14. A circuit board assembly, characterized by The heat-conducting pad comprises: a circuit board; a chip and a heat sink, the chip being arranged on the circuit board, and the heat sink being arranged on the chip; the heat-conducting pad of any one of claims 1-13 is arranged between the chip and the heat sink.

15. An electronic device, comprising: The heat-conducting pad comprises: a housing; the circuit board assembly of claim 14 is arranged in the housing.

Images