Heat conduction pad, circuit board assembly and electronic equipment
By designing a structure including a thermal conductive layer, a rebound barrier and two-layer edge sealing layer on the graphene thermal pad, the problem of cracking and powder loss during use of the thermal conductive pad is solved, achieving smaller heat conduction interface loss and higher overall strength.
Patent Information
- Application Number
- CN202421251443.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-03
- Publication Date
- 2025-05-06
- Estimated Expiration
- 2034-06-03
AI Technical Summary
Graphene thermal pads are prone to cracking or powder loss during use, resulting in large losses in the heat conduction interface, limiting their application.
A thermal pad structure is adopted that includes a thermal conductive layer, a rebound fence and two edge sealing layers. The two edge sealing layers cover part of the end surface of the rebound enclosure, reducing the width of the edge sealing layer covering the thermally conductive layer and reducing the loss of the heat conduction interface.
It effectively reduces the risk of cracking and powder loss during use of graphene thermal pads, reduces the loss of heat conduction interface, and improves the overall strength and stability of thermal pads.
Smart Images
Figure CN222838398U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of heat conduction technology, and in particular to a thermal conductive pad, a circuit board assembly and an electronic device. Background Art
[0002] In order to improve the heat exchange efficiency between the chip and the outside world, a thermal pad is set between the chip and the radiator to quickly transfer the heat of the chip to the radiator for heat dissipation. Among them, the graphene thermal pad has a high thermal conductivity and can be used for chip heat dissipation. However, the strength of the graphene thermal pad in the thickness direction is significantly higher than the cohesive strength in the width direction, which causes the graphene thermal pad to crack or fall off at the side edges during use. Graphene powder has good electrical conductivity, and falling to the chip pins will cause the risk of chip short circuit. Thus, the application of graphene thermal pads is limited.
[0003] In order to reduce the risk of cracking and powdering of the graphene thermal pad during use, a tape layer or a structural adhesive layer can be applied around the graphene thermal pad for edge wrapping. However, this edge wrapping structure will occupy a larger thermal conductive area on the surface of the graphene thermal pad, resulting in large thermal conduction interface losses. Utility Model Content
[0004] The present application provides a thermal pad, a circuit board assembly and an electronic device, which solve the problem that the existing edge wrapping structure causes large thermal conduction interface loss of the graphene thermal pad.
[0005] In order to achieve the above objectives, this application adopts the following technical solutions:
[0006] In the first aspect, an embodiment of the present application provides a thermal pad. The thermal pad includes a thermally conductive layer, a resilient enclosure, and two layers of edge sealing layers. The thermal pad may be a graphene film stacked in multiple layers. The thermal pad has a first surface and a second surface relative to each other. The resilient enclosure is arranged around the outer circumference of the thermally conductive layer. Furthermore, the resilient enclosure has a first end face and a second end face relative to each other, and both the first end face and the second end face are annular surfaces. The first end face is located on the same side as the first surface, and the second end face is located on the same side as the second surface. One layer of edge sealing layer is stacked circumferentially at the edge of the first surface of the thermally conductive layer and the first end face of the resilient enclosure. Another layer of edge sealing layer is stacked circumferentially at the edge of the second surface of the thermally conductive layer and the second end face of the resilient enclosure. Furthermore, both layers of edge sealing layers are connected to the thermally conductive layer and the resilient enclosure.
[0007] Compared with the prior art, the edge sealing structure of the thermal pad in the embodiment 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, which reduces the width of the two layers of edge sealing layers that need to cover the thermal conductive layer. In other words, a narrower edge sealing layer (such as a width less than 2 mm) can be used. The coverage area of the two layers of edge sealing layers on the thermal conductive layer is low, the heat conduction interface loss is small, and the overall compressive stress of the thermal conductive layer is also less affected. In addition, the edge sealing structure of the embodiment of the present application can also reduce the risk of cracking and powdering of the multi-layer stacked graphene thermal conductive film during use.
[0008] Therefore, in some embodiments of the present application, the width of the edge sealing layer covering the thermal conductive layer is 0.1 to 0.5 mm, ensuring that the area of the edge sealing layer covering the thermal conductive pad accounts for a lower proportion of the total surface area of the thermal conductive pad, resulting in less loss at the heat conduction interface and less impact on the overall compressive stress of the thermal conductive pad.
[0009] Based on the structure of the thermal pad, in some embodiments of the present application, the edge sealing layer includes a double-sided adhesive layer, which is bonded to the thermal conductive layer and the resilient enclosure. At the same time, when the thermal pad is used in the chip field, the double-sided adhesive layer in the double-layer edge sealing layer can be bonded to both the chip and the heat sink. The thermal pad is fixed to the heat sink and the chip to prevent mutual dislocation or slippage during transportation.
[0010] Furthermore, in some embodiments, the thermal pad may further include an adhesive layer, which is diffracted around the outer periphery of the thermal conductive layer. Furthermore, the adhesive layer bonds the resilient enclosure to the outer side wall of the thermal conductive layer, thereby further fixing the resilient enclosure to the thermal conductive layer.
[0011] In addition, in order to be applicable to more scenarios, in some examples of the present application, the edge sealing layer further includes a substrate layer, and the substrate layer is bonded to the side of the double-sided adhesive layer away from the heat conductive layer or the resilient enclosure.
[0012] For example, the edge sealing layer located near the radiator only includes a double-sided adhesive layer, and the edge sealing layer is bonded to the resilient enclosure, the thermal conductive layer and the radiator. The edge sealing layer located near one side of the chip may include a substrate layer and a double-sided adhesive layer, and the double-sided adhesive layer of the edge sealing layer is bonded to the resilient enclosure, the thermal conductive layer and one side surface of the substrate layer. The other side surface of the substrate layer is in contact with the chip. During transportation or rework, the radiator in this example can be easily removed from the chip, which not only avoids the chip from being misaligned with the thermal conductive layer during transportation, but also facilitates maintenance operations.
[0013] 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 0.001-0.01MPa at room temperature. When the thermal pad is assembled with the heat sink and the chip, the thermal pad will be squeezed. Under pressure, the double-sided adhesive layer of the thermal pad with the above physical parameters can have a surface bonding force greater than 0.1MPa with the thermal layer, the resilient enclosure, the heat sink, and the chip. In addition, the compressive stress of the double-sided adhesive layer after curing is lower than that of the thermal conductive layer of graphene, so that the cohesive strength of the edge sealing layer is similar to that of the thermal conductive layer of graphene. Thus, stress concentration is not easy to occur at the position where the thermal conductive layer of graphene and the edge sealing layer are attached, that is, the edge of the thermal conductive layer of graphene, which avoids the problem of bulging at the edge of the thermal conductive layer of graphene. In addition, there is no risk of cracking of the thermal conductive layer of graphene at the junction of the edge sealing area and the non-edge sealing area. Based on the above parameters, in some embodiments of the present application, the material of the double-sided adhesive layer includes any one or any combination of acrylic resin, epoxy resin and polyurethane, which has the advantages of good corrosion resistance, good wear resistance and the like.
[0014] For the above-mentioned substrate layer, in some embodiments of the present application, the Young's modulus of the above-mentioned substrate layer is greater than 10MPa at room temperature. The substrate layer can also have a surface bonding force greater than 0.1MPa with the double-sided adhesive layer under pressure, so that the cohesive strength of the edge sealing layer is similar to that of the thermal conductive layer of graphene, so as to avoid bulging or cracking problems at the edge of the thermal conductive layer of graphene. Based on the above parameters, in some embodiments of the present application, the material of the above-mentioned substrate layer includes any one or any several of a polymer film, a fabric layer, and a metal foil stacked together. These materials have the advantages of high temperature stability, much greater toughness than graphene sheets, and not easily deformed after being compressed.
[0015] For the above-mentioned resilient enclosure, in some embodiments of the present application, the resilient enclosure comprises any one of a polymer film, a fabric layer, and a metal foil, or any combination thereof. The resilient enclosure made of the above-mentioned materials has good elasticity.
[0016] In some other embodiments of the present application, the above-mentioned resilient enclosure is a polymer foam material with a compressive stress of 10 to 50 Psi under a 50% compression condition. At the same thickness, the compressive stress of the polymer foam is lower, and it has the advantages of low cost and light texture. Based on this, in some embodiments of the application, the above-mentioned polymer foam material includes any one or more of polyester, polyolefin, acrylic resin, epoxy resin and polyurethane.
[0017] In order to adapt to various application scenarios, in some embodiments of the present application, the thickness of the above-mentioned reboundable enclosure is equal to the thickness of the thermal conductive layer, which can be suitable for thin thermal conductive layers, such as thermal conductive layers with a thickness of less than 0.3 mm, making the processing of the reboundable enclosure more convenient.
[0018] In other embodiments of the present application, the thickness of the above-mentioned reboundable enclosure is smaller than the thickness of the thermal conductive layer, and can be used in scenarios where the thickness of the thermal conductive layer is larger, such as when the thickness of the thermal conductive layer is greater than 0.3 mm, so that the reboundable enclosure has less impact on the thermal conductive pad.
[0019] In a second aspect, the embodiment of the present application further includes a circuit board assembly, including a circuit board, a chip, a heat sink, and the thermal pad described in the above embodiment. The chip is arranged on the circuit board. The heat sink is arranged on the chip. The thermal pad is arranged between the heat sink and the chip. Since the thermal pad in the circuit board assembly of the embodiment of the present application has the same structure as the thermal pad described in the above embodiment, both can solve the same technical problems and obtain the same technical effects, and will not be repeated here.
[0020] In a third aspect, the embodiment of the present application further includes an electronic device, including a housing and the circuit board assembly described in the above embodiment. The circuit board assembly is arranged in the housing. Since the circuit board assembly in the electronic device of the embodiment of the present application has the same structure as the circuit board assembly described in the above embodiment, both can solve the same technical problems and obtain the same technical effects, and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In order to illustrate the technical solution of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be described below.
[0022] Figure 1 This is a schematic diagram of the structure of the electronic device of the embodiment of the present application, which is a notebook computer;
[0023] Figure 2 This is a schematic diagram of the structure of the circuit board assembly of the embodiment of the present application;
[0024] Figure 3 This is a schematic diagram of the assembly structure of the mainboard, the heat sink and the thermal pad in the circuit board assembly of the embodiment of the present application;
[0025] Figure 4 (a), (b), and (c) are schematic diagrams of the structure of the first thermal conductive pad with a tape layer or a structural adhesive layer in the related art when not under pressure, when under pressure and ...
[0026] Figure 5 (a) and (b) are schematic diagrams of the structure of the second thermal conductive pad with a tape layer or a structural adhesive layer in the related art when it is not compressed and when it is compressed;
[0027] Figure 6 This is a schematic diagram of the assembly structure of the thermal pad, the heat sink and the chip in the embodiment of the present application;
[0028] Figure 7 A top view of a heat-conducting layer and a resilient enclosure in a heat-conducting pad according to an embodiment of the present application;
[0029] Figure 8 This is one of the structural schematic diagrams of the thermal pad in the embodiment of the present application;
[0030] Fig. 9 This is the second structural schematic diagram of the thermal pad in the embodiment of the present application;
[0031] Fig.10 This is a schematic diagram of the structure of a thermal pad with an adhesive layer according to an embodiment of the present application;
[0032] Fig.11 This is a schematic diagram of the structure of a thermally conductive pad having a substrate layer according to an embodiment of the present application;
[0033] Fig.12 It is a schematic diagram of the assembly structure of a thermal pad, a heat sink and a chip with a cover in an embodiment of the present application;
[0034] Fig.13 This is a structural schematic diagram of a thermal pad in an embodiment of the present application in which the thickness of the reboundable enclosure is smaller than the thickness of the thermal conductive layer.
[0035] Figure Number:
[0036] 1000-laptop computer; 100-display screen; 200-body shell; 300-keyboard; 400-circuit board assembly; 10-motherboard; 20-heat sink; 30-thermal pad; 1-thermal conductive layer; 11-first surface; 12-second surface; 2-resilient enclosure; 21-first end face; 22-second end face; 3 / 3a / 3b-edge sealing layer; 31-double-sided adhesive layer; 32-base material layer; 4-adhesive layer; 40-chip; 401-lid; 010-tape layer or structural adhesive layer. DETAILED DESCRIPTION
[0037] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings.
[0038] In the following, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.
[0039] In addition, in the present application, directional terms such as "up", "down", "left", "right", "horizontal" and "vertical" are defined relative to the orientation of the components in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, and they may change accordingly according to the changes in the orientation of the components in the drawings.
[0040] In this application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can refer to the connection of mechanical structure or physical structure. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be directly connected or indirectly connected through an intermediate medium. It can also be understood as the physical contact and electrical conduction of components, and it can also be understood as the form in which different components in the circuit structure are connected through physical lines such as PCB copper foil or wires that can transmit electrical signals.
[0041] The present application provides an electronic device, which may 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, AR helmets, virtual reality (VR) glasses, VR helmets, routers, servers or switches and other devices. The embodiments of the present application do not impose any special restrictions on the specific form of the above-mentioned electronic devices. For the convenience of explanation below, the electronic device is taken as an example. Figure 1 The illustrated laptop computer is used as an example.
[0042] Please refer to Figure 1 and Figure 2 , Figure 1 The electronic device provided for some embodiments of the present application is a three-dimensional diagram of a laptop computer. Figure 2 It is a schematic diagram of the structure of the circuit board assembly in the electronic device according to the embodiment of the present application. As can be seen from the above, the laptop computer 1000 may include a display screen 100, a body shell 200, a keyboard 300, a circuit board assembly 400 and a battery.
[0043] The display screen 100 and the housing 200 may be connected in a rotatable manner (eg, hinged). The keyboard 300 may be embedded in the housing 200. The circuit board assembly 400 and the battery are disposed in the housing 200. Figure 2 and Figure 3As shown, the circuit board assembly 400 includes a mainboard 10 (which may be a printed circuit board), and various electronic components such as a chip 40, a heat sink 20, a hard disk, a memory, various interfaces, an expansion slot, a sound card, a power supply, and other auxiliary components such as a thermal pad 30 arranged on the mainboard. Figure 3 As shown, the heat sink 20 can be disposed on a high-power chip via a thermal pad 30 .
[0044] Understandably, Figure 1 and Figure 2 Only some components of the electronic device 1000 are schematically shown, and the actual shapes, sizes, positions and structures of these components are not subject to the present invention. Figure 1 and Figure 2 restrictions.
[0045] The graphene thermal pad has a high thermal conductivity. If the thermal pad 30 is a graphene thermal pad. Figure 3 The strength in the Z-axis direction is significantly higher than that in the width direction ( Figure 3 The cohesive strength in the X-axis direction (in the middle) of the graphene thermal pad causes the graphene thermal pad to crack or shed powder at the side edges during use. Graphene powder has good electrical conductivity and falls onto the chip pins, which may cause the chip to short-circuit. This limits the application of graphene thermal pads.
[0046] In order to reduce the risk of graphene thermal pads cracking and powdering during use, you can Figure 4 or Figure 5 As shown, a tape layer or a structural adhesive layer 010 is attached to the periphery of the graphene thermal pad for hemming. However, this hemming structure will occupy a larger thermal conductive area on the surface of the graphene thermal pad, reducing the effective thermal conductive area of the thermal pad 30, resulting in a large loss of the thermal conduction interface. In addition, this hemming structure will also cause the tape layer or the structural adhesive layer 010 to be separated from part of the surface of the graphene thermal pad when the graphene thermal pad is installed under pressure (such as 40% compression in the thickness direction), thus affecting the hemming effect.
[0047] For example, Figure 4 After the graphene thermal pad and the tape layer or the structural adhesive layer 010 in (a) are subjected to pressure, Figure 4 The thickness of the graphene thermal pad shown in (b) is compressed by 40%, the tape layer or structural adhesive layer 010 is deformed from a horizontally placed U-shape to a horizontally placed arc shape, and the outer wall of the graphene thermal pad is separated from the tape layer or structural adhesive layer 010. Alternatively, it can be obtained Figure 4 The thickness of the graphene thermal pad shown in (c) is compressed by 40%, and the tape layer or structural adhesive layer 010 is deformed from a laterally placed U-shape to a laterally placed U-shape with a triangular bottom, and the outer side wall of the graphene thermal pad is also detached from the tape layer or structural adhesive layer 010. Figure 5 After the graphene thermal pad and the tape layer or the structural adhesive layer 010 in (a) are subjected to pressure, Figure 5 The thickness of the graphene thermal pad shown in (b) is compressed by 40%, and the tape layer or structural adhesive layer 010 is deformed, so that the outer side wall of the graphene thermal pad is also separated from the tape layer or structural adhesive layer 010.
[0048] In order to solve the above problems, the present application embodiment proposes a thermal pad 30 with an improved structure. Figure 6 and Figure 7 The thermal pad 30 includes a thermal conductive layer 1 , a resilient baffle 2 and two edge sealing layers 3 .
[0049] The heat-conducting layer 1 may be a graphene film stacked in multiple layers. For example, the graphene heat-conducting film may be formed by stacking layers and bonding with an adhesive. Then, the graphene heat-conducting film is cut into a desired shape so that the graphene heat-conducting film is arranged along the thickness direction (i.e., the heat transfer direction). Thus, the desired heat-conducting layer 1 is obtained. In addition, the heat-conducting layer 1 has a first surface 11 and a second surface 12 opposite to each other.
[0050] The resilient enclosure 2 is arranged around the outer circumference of the heat-conducting layer 1. In addition, the resilient enclosure 2 has a first end face 21 and a second end face 22 opposite to each other. The first end face 21 and the second end face 22 are both annular surfaces. The first end face 21 is located on the same side as the first surface 11 of the heat-conducting layer 1. The second end face 22 is located on the same side as the second surface 12 of the heat-conducting layer 1.
[0051] In the above two edge sealing layers 3 (edge sealing layer 3a and edge sealing layer 3b respectively), one edge sealing layer 3a is stacked circumferentially at the edge of the first surface 11 of the heat conducting layer 1 and the first end surface 21 of the resilient enclosure 2. The other edge sealing layer 3b is stacked circumferentially at the edge of the second surface 12 of the heat conducting layer 1 and the second end surface 22 of the resilient enclosure 2. In addition, both edge sealing layers 3 are connected to the heat conducting layer 1 and the resilient enclosure 2.
[0052] Compared to Figure 4 and Figure 5The thermal pad 30 shown, the edge sealing structure of the thermal pad 30 of the embodiment of the present application includes a resilient enclosure 2 and two layers of edge sealing layers 3. The two layers of edge sealing layers 3 can cover part of the end surface of the resilient enclosure 2 as an edge sealing support structure, which reduces the width of the two layers of edge sealing layers 3 that need to cover the thermal conductive layer 1. That is, a narrower edge sealing layer 3 can be used. The coverage area of the two layers of edge sealing layers 3 on the thermal conductive layer 1 is low, the heat conduction interface loss is small, and the overall compressive stress of the thermal conductive layer 1 is also less affected. In addition, the thermal pad 30 of the embodiment of the present application can not only reduce the risk of cracking and powdering of the multi-layer stacked graphene thermal conductive film during use, but also has higher edge protection for the thermal conductive layer 1 and tensile strength of the thermal pad 30, and the edge sealing layer 3 will not be detached from the thermal conductive layer 1 when it is installed under pressure (40% compression in the thickness direction).
[0053] Based on this, in some embodiments of the present application, Figure 8 As shown, the width W1 of the edge sealing layer 3 covering the thermal conductive layer 1 is 0.1-0.5 mm, which ensures that the area of the edge sealing layer 3 covering the thermal conductive pad 30 accounts for a relatively low proportion of the total surface area of the thermal conductive pad 30, the heat conduction interface loss is small, and the overall compressive stress of the thermal conductive pad 30 is also less affected. Accordingly, the total width W0 of the edge sealing layer 3 ranges from 0.5 mm to 2 mm.
[0054] In addition, the bonding surface of the graphene thermal conductive film itself is not sticky, and the friction force at the contact interface with the electronic device (such as the chip 40) is small, which causes the graphene thermal conductive film to be easily misplaced or shifted during actual operation. In order to avoid the above problems, in some embodiments of the present application, the edge sealing layer 3a includes Fig. 9 The double-sided adhesive layer 31 shown in the figure has one side of the double-sided adhesive layer 31 bonded to the heat conducting layer 1, and the other side of the double-sided adhesive layer 31 bonded to the heat sink 20. Alternatively, the edge sealing layer 3b includes: Fig. 9 The double-sided adhesive layer 31 shown has one side surface of the double-sided adhesive layer 31 bonded to the edge sealing layer 3, and the other side surface of the double-sided adhesive layer 31 bonded to the chip 40. The double-sided adhesive layer 31 in the two layers of edge sealing layers 3 can be bonded to the chip 40 and the heat sink 20 respectively. The thermal pad 30 is fixed to the heat sink 20 and the chip 40 to prevent mutual dislocation or slippage during transportation.
[0055] Furthermore, the thickness of the double-sided adhesive layer 31 may be 5-50 um to ensure the fixing effect on 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 thermal pad 30 may also include Fig.10The adhesive layer 4 shown is diffracted around the outer periphery of the heat-conducting layer 1. Moreover, the adhesive layer 4 bonds the resilient enclosure 2 to the outer side wall of the heat-conducting layer 1. Thus, the resilient enclosure 2 is further fixed to the heat-conducting layer 1. Specifically, the material of the adhesive layer 4 includes any one or both of acrylic resin and polyurethane.
[0057] However, considering that the chip 40 is easy to be taken out during repair, and the thermal pad 30 is easy to be removed when the heat sink 20 is disassembled for rework, in some examples of the present application, the edge sealing layer 3 further includes: Fig.11 The substrate layer 32 shown is located on the side of the double-sided adhesive layer 31 away from the heat conductive layer 1 or the resilient baffle 2 .
[0058] For example, continue to refer to Fig.11 , the edge sealing layer 3a located near the heat sink 20 only includes a double-sided adhesive layer 31, and the double-sided adhesive layer 31 is bonded to the resilient enclosure 2, the thermal conductive layer 1 and the heat sink 20. The edge sealing layer 3b located near the side of the chip 40 may include a substrate layer 32 and a double-sided adhesive layer 31, and the double-sided adhesive layer 31 is bonded to the resilient enclosure 2, the thermal conductive layer 1, and one side surface of the substrate layer 32. The other side surface of the substrate layer 32 is in contact with 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 rework, which not only avoids the chip 40 from being misaligned with the thermal conductive layer 1 during transportation, but also facilitates maintenance operations.
[0059] Since the cohesive strength of the area covered with the edge sealing layer 3 on the thermal conductive layer 1 is much greater than the cohesive strength of the area not covered with the edge sealing layer, when the graphene thermal conductive pad is compressed in the thickness direction, stress concentration is likely to occur in the area covered with the edge sealing layer 3 on the thermal conductive layer 1. At the same time, bulging is inevitably generated at the connection between the thermal conductive layer 1 and the edge sealing layer 3. In particular, there is a risk of cracking at the joint between the area covered with the edge sealing layer 3 and the uncovered area on the thermal conductive layer 1.
[0060] In order to avoid the above problems, in some embodiments of the present application, the storage modulus of the double-sided adhesive layer 31 is 0.001-0.01MPa at room temperature. When the thermal pad 30 is assembled with the heat sink 20 and the chip 40, the thermal pad 30 will be squeezed. When the thermal pad 30 is under pressure, the double-sided adhesive layer 31 with the above parameters can have a surface bonding force greater than 0.1MPa with the thermal layer 1, the resilient enclosure 2, the heat sink 20, and the chip 40. In addition, the compressive stress of the double-sided adhesive layer 31 after curing is lower than that of the graphene thermal conductive layer 1, so that the cohesive strength of the edge sealing layer 3 is similar to that of the graphene thermal conductive layer 1. As a result, the position where the graphene thermal conductive layer 1 and the edge sealing layer 3 are attached, that is, the edge of the graphene thermal conductive layer 1, is not prone to stress concentration, which avoids the problem of bulging at the edge of the graphene thermal conductive layer 1. Furthermore, the risk of cracking of the graphene heat-conducting layer 1 at the junction of the edge-sealed area and the non-edge-sealed area 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 to 0.01 MPa at room temperature may include any one or any combination of acrylic resin, epoxy resin and polyurethane, and has the advantages of good corrosion resistance and wear resistance.
[0062] For the edge sealing layer 3 having the 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 greater than 0.1 MPa with the double-sided adhesive layer 31 under pressure, so that the cohesive strength of the edge sealing layer 3 is similar to that of the graphene thermal conductive layer 1, so as to avoid bulging or cracking of the edge of the graphene thermal conductive 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 of a polymer film, a fabric layer, and a metal foil, or any combination thereof. These materials have the advantages of high temperature stability, much greater toughness than graphene sheets, and not easily deformed after being compressed.
[0064] The above mainly describes the edge sealing layer 3. For the above-mentioned resilient enclosure 2, in some embodiments of the present application, the above-mentioned resilient enclosure 2 includes any one of a polymer film, a fabric layer, and a metal foil, or any of several layers thereof. The resilient enclosure 2 made of these materials has good elasticity.
[0065] In other embodiments of the present application, the resilient enclosure 2 is a polymer foam material having a compressive stress of 10 to 50 Psi (pounds per square inch) under a 50% compression condition. At the same thickness, the polymer foam has a lower compressive stress and has the advantages of low cost and light weight. For example, the polymer foam material includes any one or more of polyester, polyolefin, acrylic resin, epoxy resin and polyurethane.
[0066] It should be noted that the thermal pad 30 of the above structure and material can be used not only for heat dissipation of bare chips (bare dies), but also for packaged chips. Fig.12 A lid 401 is shown.
[0067] Furthermore, for heat-conducting layers 1 of different thicknesses, the thickness T1 of the above-mentioned resilient enclosure 2 can be different. In some embodiments of the present application, the thickness T1 of the above-mentioned resilient enclosure 2 is equal to the thickness T2 of the heat-conducting layer 1, which can be applicable to heat-conducting layers 1 of small thickness, such as the thickness T2 of the heat-conducting layer 1 is less than 0.3 mm, so that the process of the resilient enclosure 2 is more convenient.
[0068] In other embodiments of the present application, Fig.13 As shown, the thickness T1 of the above-mentioned resilient enclosure 2 is less than the thickness T2 of the heat-conducting layer 1, and can be applied to the scene where the thickness T2 of the heat-conducting layer 1 is larger, such as the thickness T2 of the heat-conducting layer 1 is greater than 0.3 mm, so that the resilient enclosure 2 has less impact on the heat-conducting pad 30. For example, the thickness T1 of the resilient enclosure 2 is 40-60% of the thickness T2 of the heat-conducting layer 1.
[0069] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.
Claims
1. A thermal pad, characterized in that: include: a heat conductive layer having a first surface and a second surface opposite to each other; A resilient enclosure, the resilient enclosure being arranged around the outer circumference of the heat conductive layer; The resilient enclosure has a first end face and a second end face opposite to each other; the first end face and the first surface are located on the same side, and the second end face and the second surface are located on the same side; Two edge sealing layers, one edge sealing layer is stacked circumferentially at the edge of the first surface of the heat conductive layer and the first end surface of the resilient enclosure; the other edge sealing layer is stacked at the edge of the second surface of the heat conductive layer and the second end surface of the resilient enclosure, and the two edge sealing layers are connected to the heat conductive layer and the resilient enclosure.
2. The thermal pad according to claim 1, characterized in that: The edge sealing layer includes a double-sided adhesive layer, and the double-sided adhesive layer is bonded to the heat conductive layer and the resilient enclosure.
3. The thermal pad according to claim 2, characterized in that: The storage modulus of the double-sided adhesive layer is 0.001-0.01 MPa at room temperature.
4. The thermally conductive pad according to claim 2 or 3, characterized in that: The material of the double-sided adhesive layer includes any one of acrylic resin, epoxy resin and polyurethane.
5. The thermally conductive pad according to claim 2 or 3, characterized in that: The edge sealing layer further comprises a substrate layer, and the substrate layer is bonded to a surface of the double-sided adhesive layer on a side away from the heat conductive layer or the resilient enclosure.
6. The thermal pad according to claim 5, characterized in that: The Young's modulus of the substrate layer is greater than 10 MPa at room temperature.
7. The thermally conductive pad according to claim 5, characterized in that: The material of the substrate layer includes any one of a polymer film, a fabric layer, and a metal foil, or a stack of any of the above.
8. The thermally conductive pad according to any one of claims 1 to 3, characterized in that: The resilient enclosure comprises any one of a polymer film, a fabric layer, and a metal foil or any combination thereof; Alternatively, the resilient enclosure is a polymer foam material having a compressive stress of 10 to 50 Psi under a 50% compression condition.
9. The thermal pad according to claim 8, characterized in that: The polymer foam material includes any one of polyester, polyolefin, acrylic resin, epoxy resin and polyurethane.
10. The thermally conductive pad according to any one of claims 1 to 3, characterized in that: The width of the edge sealing layer covering the heat conducting layer is 0.1-0.5 mm.
11. The thermally conductive pad according to any one of claims 1 to 3, characterized in that: The thermal pad also includes: An adhesive layer is provided, wherein the adhesive layer is diffracted around the outer periphery of the heat-conducting layer and bonds the resilient enclosure to the outer side wall of the heat-conducting layer.
12. The thermally conductive pad according to any one of claims 1 to 3, characterized in that: The thickness of the resilient enclosure is equal to the thickness of the heat-conducting layer; or, the thickness of the resilient enclosure is less than the thickness of the heat-conducting layer.
13. The thermally conductive pad according to any one of claims 1 to 3, characterized in that: The heat-conducting layer includes multiple layers of graphene films stacked in sequence.
14. A circuit board assembly, characterized in that: include: Circuit boards; A chip and a heat sink, wherein the chip is arranged on the circuit board; and the heat sink is arranged on the chip; The thermal pad according to any one of claims 1 to 13, wherein the thermal pad is arranged between the chip and the heat sink.
15. An electronic device, characterized in that: include: shell; The circuit board assembly as claimed in claim 14 is disposed in the housing.