A high-thermal-conductivity low-loss multilayer PCB for new energy vehicles and a preparation process thereof

Abstract

This application belongs to the field of PCB manufacturing technology, and particularly relates to a high thermal conductivity, low loss multilayer PCB for new energy vehicles and its manufacturing process. The multilayer PCB includes a PCB board body and thermally conductive elements embedded within the PCB board body. This application uses a specially made sandwich insulating layer to replace the prepreg in conventional PCBs, and forms a first copper plating on the side of the PCB board body. The first copper plating on the side and the thermally conductive film in the sandwich insulating layer form a Faraday cage, so that the circuits in the PCB board body except for the first and last layers are wrapped in a shielded space, which can shield high-frequency changing magnetic fields and solve the problem of high PCB loss caused by leakage magnetic fields of electric vehicle motors. Secondly, blind via thermally conductive elements can be used in conjunction with multiple thermally conductive films for heat dissipation, instead of only using through-hole thermally conductive elements, which can save wiring space of the multilayer PCB to the greatest extent, thereby reducing the size of the PCB and solving the problem of excessive size of existing high thermal conductivity multilayer PCBs.

Description

Technical Field

[0001] This application belongs to the field of PCB manufacturing technology, and in particular relates to a high thermal conductivity, low loss multilayer PCB for new energy vehicles and its manufacturing process. Background Technology

[0002] The new energy vehicle industry has developed rapidly in recent years, and the market share of electric vehicles has repeatedly reached new highs. As the carrier of electronic components in new energy vehicles, the quality of PCBs can reflect the quality of electronic devices in new energy vehicles to a certain extent.

[0003] Because of the inherent heat generation and susceptibility to ambient temperature in automobiles, PCBs used in new energy vehicles need to have better thermal conductivity than ordinary PCBs. However, when existing high thermal conductivity PCBs are directly used in new energy vehicles, there are problems caused by not considering the specific characteristics of new energy vehicles. These problems include: not considering that the electric motor may leak magnetic field, and the high-frequency changing magnetic field leaked by the motor will induce current in the PCB circuit, increasing the circuit loss of the PCB; and not considering the compact interior space of automobiles. Existing high thermal conductivity PCBs usually use through holes for heat conduction. When the PCB is multilayered, using through holes for heat conduction will significantly increase the size of the multilayer PCB. Summary of the Invention

[0004] This application provides a high thermal conductivity, low loss multilayer PCB for new energy vehicles and its fabrication process, which can solve the problems of high PCB loss caused by the high frequency changing magnetic field generated by the motor of electric vehicles and the excessive size of existing high thermal conductivity multilayer PCBs.

[0005] In a first aspect, embodiments of this application provide a high thermal conductivity, low loss multilayer PCB for new energy vehicles, comprising:

[0006] The PCB board body includes a circuit layer, a core insulating layer, and a substrate layer. The core insulating layer is disposed between the circuit layer and the substrate layer, and at least two core insulating layers are respectively located on opposite sides of the substrate layer. The core insulating layer includes a thermally conductive insulating adhesive and a thermally conductive film. The thermally conductive film is sandwiched within the thermally conductive insulating adhesive, and the edges of the thermally conductive film protrude from the sides of the thermally conductive insulating adhesive.

[0007] The first copper plating covers the side of the PCB board body, and the first copper plating and the thermally conductive film of each of the sandwich insulation layers form a shielding space.

[0008] Second copper plating;

[0009] A thermally conductive element is embedded within the PCB board body and connected to at least one layer of the thermally conductive film via a second copper plating. The top of the thermally conductive element is exposed above the circuit layer for soldering to a heat-generating element. The thermally conductive element can be either a first-type or a second-type thermally conductive element. The first-type thermally conductive element is a cylindrical structure embedded in a blind hole in the PCB board body, and its inner wall is connected to at least one layer of the thermally conductive film via the second copper plating. The second-type thermally conductive element is a solid columnar element embedded in a through-hole in the PCB board body, and its outer wall is connected to all the thermally conductive films via the second copper plating. The bottom of the second-type thermally conductive element is used for soldering to a heat-dissipating element.

[0010] The technical solutions described in this application embodiment have at least the following technical effects:

[0011] The high thermal conductivity, low loss multilayer PCB for new energy vehicles provided in this application, firstly, uses a specially designed sandwich insulating layer to replace the prepreg in conventional PCBs, and forms a first copper plating on the side of the multilayer PCB. This first copper plating on the side, together with the thermally conductive film within the sandwich insulating layer, forms a shielding space, which can act as a Faraday cage. This allows the circuitry of the multilayer PCB, except for the first and last layers, to be enclosed in the shielding space, effectively shielding against high-frequency changing magnetic fields and solving the problem of high PCB loss caused by leakage magnetic fields from electric vehicle motors. Secondly, blind via thermal conductive elements can be used in conjunction with multiple thermally conductive films for heat dissipation, eliminating the need for through-hole thermal conductive elements and solving the problem of excessively large size in existing high thermal conductivity multilayer PCBs.

[0012] In a second aspect, embodiments of this application provide a method for preparing a sandwich insulation layer, used to manufacture the sandwich insulation layer as described in the first aspect, comprising:

[0013] A roll of thermally conductive material is provided, from which a thermally conductive material film is released and passed through an insulating adhesive pool, so that both sides of the thermally conductive material film are uniformly impregnated with thermally conductive insulating adhesive; wherein, the thermally conductive material film is a copper film or an aluminum film;

[0014] The thermally conductive material film is passed through a scraping device to remove excess thermally conductive insulating adhesive, and then semi-cured and cut to a fixed size to obtain a sandwich insulating sheet.

[0015] Based on the first shape of the PCB board body, the sandwich insulating sheet is cut into a second shape. Then, the thermally conductive insulating adhesive of the cut sandwich insulating sheet is liquefied by heating. A fixed depth of thermally conductive insulating adhesive is scraped off the edge of the sandwich insulating sheet, so that the part of the sandwich insulating sheet with thermally conductive insulating adhesive is in the first shape, thus obtaining the sandwich insulating layer. The first shape is the shape of the projection of the PCB board body on a set plane, and the second shape is the shape of the projection of the sandwich insulating sheet on the set plane. The set plane is perpendicular to the stacking direction of the thermally conductive insulating adhesive and the thermally conductive material film. The second shape is a similar shape to the first shape, and the area of ​​the second shape is larger than the area of ​​the first shape.

[0016] The technical solutions described in this application embodiment have at least the following technical effects:

[0017] The fabrication process of the sandwich insulation layer provided in this application involves first uniformly impregnating both sides of a thermally conductive material film with thermally conductive insulating adhesive. After adhesive scraping, semi-curing, and cutting, a regular, fixed-size sandwich insulation sheet is obtained. Then, the sandwich insulation sheet is cut into a second shape based on a first shape. The second shape is a similar image slightly larger than the first shape. Finally, the thermally conductive insulating adhesive is liquefied by heating, and a fixed depth of thermally conductive insulating adhesive is scraped off from the edge of the second-shaped sandwich insulation sheet, leaving the portion of the sandwich insulation sheet with thermally conductive insulating adhesive in the first shape. This yields a sandwich insulation layer that meets the requirements. This fabrication process can produce a sandwich insulation layer with a thermally conductive film sandwiched in the middle of a thermally conductive insulating adhesive layer, where the area of ​​the thermally conductive film is larger than that of the thermally conductive insulating adhesive.

[0018] Thirdly, embodiments of this application provide a fabrication process for a high thermal conductivity, low loss multilayer PCB for new energy vehicles, used to manufacture the high thermal conductivity, low loss multilayer PCB for new energy vehicles as described in the first aspect, comprising:

[0019] The sandwich insulating layer and the substrate layer are provided in corresponding shapes and quantities, and the two sides of the substrate layer are chemically etched to form a circuit according to the circuit design.

[0020] The core insulating layer and the substrate layer are stacked sequentially, and copper plating and chemical etching are performed on the upper and lower surfaces of the board layer formed after stacking the core insulating layer and the substrate layer to obtain the circuit layer, so as to obtain the PCB board body.

[0021] The category of the heat-conducting element is determined according to the heat dissipation requirement level of the heat-generating element;

[0022] When the heat-conducting element is the first type of heat-conducting element, a blind slot is opened on the component side of the PCB board body, the first type of heat-conducting element is filled in the blind slot, and then a heat-conducting hole is opened downward from the internal space of the first type of heat-conducting element, and copper is deposited in the heat-conducting hole to obtain the second copper plating; wherein, the heat-conducting hole is a blind hole, the heat-conducting hole passes through at least one layer of the heat-conducting film, and the depth of the heat-conducting hole is proportional to the heat dissipation requirement level;

[0023] When the heat-conducting element is the second type of heat-conducting element, a first through hole is opened on the PCB board body, and copper plating is performed in the first through hole to obtain the second type of copper plating, and then the second type of heat-conducting element is filled into the first through hole.

[0024] Solder resist layers are applied to the top and bottom surfaces of the PCB board body, and then copper plating is applied to the sides to obtain the first copper plating.

[0025] Fourthly, embodiments of this application provide a high thermal conductivity, low loss multilayer PCB fabrication device for new energy vehicles, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the method described in any of the third aspects above.

[0026] It is understandable that the beneficial effects of the third and fourth aspects mentioned above can also be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the main structure of a high thermal conductivity, low loss multilayer PCB for new energy vehicles provided in an embodiment of this application;

[0029] Figure 2 This is a schematic diagram of the structure of a first category of thermally conductive element and an eight-layer PCB board body of a high thermal conductivity and low loss multilayer PCB for new energy vehicles provided in an embodiment of this application.

[0030] Figure 3 This is a schematic diagram of the structure of a second type of thermally conductive element and an eight-layer PCB board body for a high thermal conductivity and low loss multilayer PCB for new energy vehicles provided in an embodiment of this application;

[0031] Figure 4This is a schematic flowchart of a method for preparing a sandwich insulation layer according to an embodiment of this application;

[0032] Figure 5 This is a schematic flowchart of the fabrication process of a high thermal conductivity, low loss multilayer PCB for new energy vehicles provided in one embodiment of this application.

[0033] The following are the labeling elements in the figure:

[0034] 100. PCB board body; 1. Circuit layer; 2. Sandwich insulation layer; 21. Thermally conductive film; 22. Thermally conductive insulating adhesive; 3. Substrate layer; 41. First category of thermally conductive elements; 42. Second category of thermally conductive elements; 5. Heat-generating elements; 61. First copper plating; 62. Second copper plating; 7. Heat dissipation elements. Detailed Implementation

[0035] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application. The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0037] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0038] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0040] In this application, "and / or" is merely a way of describing the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0041] It should be noted that in this application, the words "in some embodiments," "exemplarily," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "in some embodiments," "exemplarily," or "for example" should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of words such as "in some embodiments," "exemplarily," and "for example" is intended to present related concepts in a specific manner, meaning that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of this application. The appearance of the above words in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0042] In related technologies, due to the inherent heat generation and susceptibility to ambient temperature in automobiles, PCBs used in new energy vehicles require better thermal conductivity than ordinary PCBs. However, when existing high thermal conductivity PCBs are directly used in new energy vehicles, problems arising from the specific scenarios of these vehicles are not considered. These problems include: the potential for magnetic leakage from the electric motor, which can induce current in the PCB circuitry, increasing circuit losses; and the lack of consideration for the compact interior space of automobiles, where existing high thermal conductivity PCBs typically use vias for heat conduction. When the PCB is multilayered, using vias for heat conduction significantly increases the size of the multilayer PCB.

[0043] To address the aforementioned issues, this application provides a high thermal conductivity, low loss multilayer PCB for new energy vehicles and its fabrication process. In the high thermal conductivity, low loss multilayer PCB for new energy vehicles provided in this application, firstly, a specially designed sandwich insulating layer replaces the prepreg in conventional PCBs, and a first copper plating is formed on the side of the multilayer PCB. This first copper plating on the side and the thermally conductive film within the sandwich insulating layer form a Faraday cage, encasing the circuitry of the multilayer PCB except for the first and last layers within a shielded space. This shields against high-frequency changing magnetic fields, thus solving the problem of high PCB loss caused by leakage magnetic fields from electric vehicle motors. Secondly, blind via thermal conductive elements can be used in conjunction with multiple thermally conductive films for heat dissipation, eliminating the need for through-hole thermal conductive elements and solving the problem of excessively large size in existing high thermal conductivity multilayer PCBs.

[0044] To better understand the high thermal conductivity and low loss multilayer PCB for new energy vehicles provided in the embodiments of this application, the following is a graphical description of the high thermal conductivity and low loss multilayer PCB for new energy vehicles provided in the embodiments of this application.

[0045] Please refer to the following: Figures 1 to 3 This application provides a high thermal conductivity, low loss multilayer PCB for new energy vehicles, including a PCB board body 100, a first type of thermally conductive element 41, a second type of thermally conductive element 42, a first copper plating 61, and a second copper plating 62, wherein:

[0046] The PCB board body 100 includes a circuit layer 1, a sandwich insulating layer 2, and a substrate layer 3. The sandwich insulating layer 2 is disposed between the circuit layer 1 and the substrate layer 3, and at least two sandwich insulating layers 2 are respectively located on opposite sides of the substrate layer 3. The sandwich insulating layer 2 includes thermally conductive insulating adhesive 22 and thermally conductive film 21. The thermally conductive film 21 is sandwiched in the thermally conductive insulating adhesive 22, and the four edges of the thermally conductive film 21 protrude from the sides of the thermally conductive insulating adhesive 22.

[0047] The first copper plating 61 covers the side of the PCB board body 100, and the first copper plating 61 and the thermal conductive film 21 of each core insulation layer 2 form a shielding space.

[0048] The heat-conducting element is embedded in the PCB board body 100 and is connected to at least one layer of heat-conducting film 21 through a second copper plating 62. The top of the heat-conducting element is exposed on the circuit layer 1 and is used to solder to the heat-generating element 5. The heat-conducting element is either a first-type heat-conducting element 41 or a second-type heat-conducting element 42. The first-type heat-conducting element 41 is a cylindrical structure and is embedded in a blind hole of the PCB board body 100. The inner wall of the first-type heat-conducting element 41 is connected to at least one layer of heat-conducting film 21 through the second copper plating 62. The second-type heat-conducting element 42 is a solid columnar element and is embedded in a through hole of the PCB board body 100. The outer wall of the second-type heat-conducting element 42 is connected to all the heat-conducting films 21 through the second copper plating 62. The bottom of the second-type heat-conducting element 42 is used to solder to the heat dissipation element 7.

[0049] It is understandable that the circuit layer is used for circuit routing and soldering electronic components. For example, circuit layer 1 can be etched from copper foil or other conductive materials. The sandwich insulation layer 2 is used to isolate the circuit and conduct heat. It is formed by semi-curing a thermally conductive film 21 and a thermally conductive insulating adhesive 22. For example, the thermally conductive insulating adhesive 22 can be epoxy resin containing high thermal conductivity ceramic powder, and the thermally conductive film 21 can be a film made of various high thermal conductivity materials. The substrate layer 3 is used to carry the inner circuit. It can be a conventional PCB substrate, which consists of two layers of copper foil sandwiching a semi-cured sheet. Both the first category of thermally conductive elements 41 and the second category of thermally conductive elements 42 are used to conduct heat from the heat-generating elements. For example, the thermally conductive elements can be made of copper, copper alloy, aluminum, or aluminum alloy. The heat-generating element 5 is an electronic component that generates heat and is soldered onto the PCB board body 100, such as a resistor, capacitor, etc. The first copper plating 61 and the second copper plating 62 are both copper films formed by the copper plating process. The first copper plating 61 is used to connect all the heat-conducting films and form a shielding space. The heat dissipation element 7 can be a multi-toothed element made of copper, copper alloy, aluminum or aluminum alloy.

[0050] It is understood that the main difference between the high thermal conductivity, low loss multilayer PCB board provided in this application and conventional PCB boards lies in the use of a sandwich insulating layer 2 instead of a prepreg. The thermally conductive film 21 within the sandwich insulating layer 2 provides the PCB board with multiple heat dissipation pathways, preventing heat from being dissipated only from the bottom of the PCB. This allows thermally conductive components to be placed in blind vias, significantly saving wiring space in multilayer PCBs. Furthermore, a first copper plating 61 is placed on the side of the PCB board, further accelerating heat dissipation. The first copper plating 61 also forms a Faraday cage with the thermally conductive film 21, reducing the influence of external magnetic fields and lowering circuit losses within the PCB.

[0051] As can be seen from the above, the high thermal conductivity and low loss multilayer PCB board for new energy vehicles provided in this application is very suitable for new energy electric vehicles, especially electric vehicles with motors. It can achieve both high thermal conductivity and low loss, and can also further reduce the size of the PCB board.

[0052] Optionally, the outer wall of the second type of heat-conducting element 42 is provided with threads, and the second type of heat-conducting element 42 is connected to the second copper plating 62 by the threads.

[0053] It is understandable that there is no further strengthening connection between the second type of heat-conducting element 42 and the second plating copper 62, and there may be gaps between them. Therefore, the second type of heat-conducting element 42 is designed as a screw-shaped element. The second type of heat-conducting element 42 is screwed into the through hole, and the threads on the second type of heat-conducting element 42 can also be further squeezed together with the second plating copper 62 to strengthen the connection.

[0054] This design prevents the second type of heat-conducting element 42 from falling off or becoming loosely connected.

[0055] Optionally, further, the second type of heat-conducting element 42 includes a heat-conducting element body and a nut, the nut being connected to the top of the heat-conducting element body, and the outer side wall of the heat-conducting element body being threaded; the nut is used to separate from the heat-conducting element body after the heat-conducting element body is connected to the second copper plating 62 by the thread.

[0056] It is understandable that the heat-conducting element body and the nut can be connected by external materials, such as glue or other adhesive materials, or by a more fragile body structure, such as cutting at the connection point to make the structure at the connection point finer. Therefore, after the heat-conducting element body is screwed into the through hole and connected to the second copper plating 62 by the nut, the nut can be separated from the heat-conducting element body.

[0057] This configuration improves the installation efficiency of the second type of heat-conducting element 42.

[0058] Optionally, all thermal conductive films 21 are grounded.

[0059] It is understandable that all the thermal conductive films 21 and all the first copper plating 61 and second copper plating 62 are electrically connected together. If this circuit is left unused, it may cause signal drift in the circuit, resulting in increased circuit loss on the PCB. Therefore, by grounding all the thermal conductive films 21, the entire lower surface circuit layer 1 can be grounded, and the first copper plating 61 can be electrically connected to the lower surface circuit layer 1, so that all the thermal conductive films 21 and all the first copper plating 61 and second copper plating 62 are grounded.

[0060] This configuration improves the stability of the PCB provided in this application.

[0061] Optionally, the thermally conductive element is made of copper, copper alloy, aluminum, or aluminum alloy; the substrate layer is an aluminum substrate.

[0062] It is understandable that using an aluminum substrate can further enhance the heat dissipation performance of the PCB provided in this application, but the side sealant of the aluminum substrate needs to be cleaned first to ensure that the aluminum layer of the aluminum substrate is connected to the first copper plating 61 in order to further improve the heat dissipation effect. The thermally conductive element is made of copper, copper alloy, aluminum, or aluminum alloy to improve the thermal conductivity.

[0063] This configuration can further improve heat dissipation.

[0064] To better understand the sandwich insulation layer preparation process provided in the embodiments of this application, the specific implementation process of the sandwich insulation layer preparation process provided in the embodiments of this application will be described by way of example below.

[0065] Figure 4 This paper illustrates a schematic flowchart of the sandwich insulation layer fabrication process provided in an embodiment of this application. The fabrication process of the sandwich insulation layer includes:

[0066] S100 provides a roll of thermally conductive material. A thermally conductive film is released from the roll and passes through an insulating adhesive pool, so that both sides of the thermally conductive film are evenly impregnated with thermally conductive insulating adhesive. The thermally conductive film is a copper film or an aluminum film.

[0067] It is understandable that the thermally conductive material film can be released at a uniform speed by an unwinding machine. The thermally conductive material film is a copper film or an aluminum film, and its thickness can be 0.1mm. The thermally conductive material film passes through an insulating glue tank, which contains thermally conductive insulating glue. Two insulating glue tanks can be set up so that the two sides of the thermally conductive material roll pass through the two insulating glue tanks with their respective sides facing down, so that the two sides of the thermally conductive material film are evenly soaked with the same amount of thermally conductive insulating glue. The insulating glue tank can be automatically replenished at a fixed speed.

[0068] Optionally, fiberglass cloth can be laid on both sides of the thermally conductive material film to increase its tensile strength.

[0069] With this setup, a thermally conductive material film with thermally conductive insulating adhesive evenly coated on both sides is obtained.

[0070] S200 involves scraping off excess thermally conductive insulating adhesive from the thermally conductive material film using a scraping device, followed by semi-curing and fixed-size cutting to obtain a sandwich insulating sheet.

[0071] It is understandable that the scraping device can be one or more scraping rollers. The thermally conductive material film is passed through the scraping rollers to scrape off the excess thermally conductive insulating adhesive on both sides. Then, it is semi-cured. The semi-curing method is different for different materials of thermally conductive insulating adhesive. Some are cured by ultraviolet light, while others are cured by high temperature and high pressure. After semi-curing, the thermally conductive insulating adhesive becomes a semi-liquid gel. The thermally conductive material film can be laid flat on a smooth aluminum conveyor belt to prevent the thermally conductive material film from sticking to the conveyor belt. Then it is cut to a fixed size to obtain a sandwich insulating sheet.

[0072] This setup yields a regular sandwich insulation sheet, which can then be cut into corresponding shapes according to different PCB shapes.

[0073] S300: Based on the first shape of the PCB board body 100, the sandwich insulating sheet is cut into a second shape. Then, the thermally conductive insulating adhesive of the cut sandwich insulating sheet is liquefied by heating. A fixed depth of thermally conductive insulating adhesive is scraped off the edge of the sandwich insulating sheet, so that the portion of the sandwich insulating sheet with thermally conductive insulating adhesive resembles the first shape, thus obtaining the sandwich insulating layer 2. The first shape is the projection of the PCB board body 100 onto a set plane, and the second shape is the projection of the sandwich insulating sheet onto the set plane. The set plane is perpendicular to the stacking direction of the thermally conductive insulating adhesive and the thermally conductive material film. The second shape is similar to the first shape, and the area of ​​the second shape is larger than the area of ​​the first shape.

[0074] It can be understood that the characteristic of the sandwich insulation layer 2 is that the area of ​​the internal thermally conductive film 21 is slightly larger than the area of ​​the thermally conductive insulating adhesive 22, resulting in a protruding thermally conductive film 21 on the side of the sandwich insulation layer 2. Therefore, based on the first shape, a second shape is obtained. The second shape is slightly larger than the first shape, and the second shape is a similar graphic to the first shape. That is, the second shape is the shape of the projection of the thermally conductive film 21 onto a set plane, and the first shape is the shape of the projection of the thermally conductive insulating adhesive 22 onto the set plane. The set plane is a plane perpendicular to the stacking direction of the thermally conductive insulating adhesive and the thermally conductive material film (i.e., the component surface). Therefore, the shape of the thermally conductive film 21 is also the shape of the sandwich insulation layer 2, and the shape of the thermally conductive insulating adhesive 22 is also the shape of the PCB board body 100. After obtaining the second shape, the sandwich insulation sheet is first cut into the second shape, then heated to liquefy the thermally conductive insulating adhesive, and then a fixed depth of thermally conductive insulating adhesive is scraped off the edge of the sandwich insulation sheet of the second shape, so that the part of the sandwich insulation sheet with thermally conductive insulating adhesive is the first shape. At this time, the sandwich insulation layer 2 is obtained.

[0075] With this configuration, the sandwich insulation layer 2 provided in this application can be obtained.

[0076] To better understand the fabrication process of the high thermal conductivity and low loss multilayer PCB for new energy vehicles provided in the embodiments of this application, the specific implementation process of the fabrication process of the high thermal conductivity and low loss multilayer PCB for new energy vehicles provided in the embodiments of this application will be described by way of example below.

[0077] Figure 5 The diagram illustrates a process flow chart of the fabrication process for a high thermal conductivity, low loss multilayer PCB for new energy vehicles provided in this application embodiment. The fabrication process for the high thermal conductivity, low loss multilayer PCB for new energy vehicles includes:

[0078] S400 provides sandwich insulating layers 2 and substrate layers 3 of corresponding shape and quantity, and performs chemical etching on both sides of substrate layer 3 to form circuits according to the circuit design.

[0079] It is understandable that after the PCB design is completed, the corresponding shape and quantity of the sandwich insulating layer 2 and substrate layer 3 are obtained. If the PCB is an N-layer board, the number of sandwich insulating layers 2 is N / 2 and the number of substrate layers 3 is (N / 2)-1. Each substrate layer 3 is pre-numbered, and the number represents the order of the substrate layers 3 from bottom to top. After the number of the substrate layers 3 is determined, the corresponding circuit is chemically etched on both sides of each substrate layer 3 according to the circuit design of the PCB.

[0080] With this setup, the sandwich insulation layer 2 and the substrate layer 3 are properly handled, and the corresponding circuits are etched on them, completing the first step in PCB manufacturing.

[0081] S500, the sandwich insulating layer 2 and the substrate layer 3 are stacked sequentially, and copper plating and chemical etching are performed on the upper and lower surfaces of the board layer formed after stacking the sandwich insulating layer 2 and the substrate layer 3 to obtain the circuit layer 1, so as to obtain the PCB board body 100.

[0082] It is understandable that after obtaining the processed sandwich insulation layer 2 and substrate layer 3, the sandwich insulation layer 2 and substrate layer 3 are stacked in the order of their numbers. For example, the stacking order of a four-layer board is: sandwich insulation layer 21 -> substrate layer 31 -> sandwich insulation layer 2. During the stacking process, the thermally conductive insulating adhesive 22 of the sandwich insulation layer 2 is completely cured, and the sandwich insulation layer 2 and substrate layer 3 are tightly bonded together. Then, copper foil is deposited on the upper and lower surfaces of the stacked board to form copper foil, and then the copper foil is chemically etched to obtain circuit layer 1. Components can be soldered on circuit layer 1.

[0083] With this setup, the prototype of the PCB was created, with the main body of the PCB board measuring 100.

[0084] S600 determines the type of heat-conducting element based on the heat dissipation requirements of heat-generating element 5.

[0085] It is understandable that different types of electronic components generate different amounts of heat. These different amounts of heat can be classified into different heat generation levels. Furthermore, the heat resistance of the electronic components can be considered, and different heat resistance levels can be classified into different heat resistance levels. Therefore, the heat dissipation requirement level of heat generation element 5 = heat generation level - heat resistance level. After obtaining the heat dissipation requirement level of heat generation element 5, a level threshold can be determined. Heat generation element 5 with a heat dissipation requirement level greater than this level threshold will use the second category of heat-conducting element 42; heat generation element 5 with a heat dissipation requirement level less than this level threshold will use the first category of heat-conducting element 41.

[0086] With this configuration, the second category of heat-conducting elements 42 are allocated according to the heat dissipation requirements of the components, which can reduce the number of through holes on the PCB board and thus reduce the size of the PCB.

[0087] Optionally, determine the heat dissipation requirement level of heat-generating element 5, including:

[0088] S610, obtain the heating power and total number of heating elements 5, and then obtain the thermal conductivity of a single thermal conductive film 21.

[0089] It can be understood that the heating power of the heating element 5 refers to the heat generated by the heating element 5 when it operates at its rated power per unit time, and the total number refers to how many heating elements 5 are on the PCB. The thermal conductivity of the thermal conductive film 21 refers to the heat transferred by the thermal conductive film 21 per unit time, which is equal to the thermal conductivity of the thermal conductive film 21 multiplied by the cross-sectional area of ​​the thermal conductive film 21.

[0090] This setup is helpful for calculating the heat dissipation requirements of each heat-generating element 5.

[0091] S620, divide the heat generation power by the heat conduction power to obtain the first ratio, and then multiply the first ratio by the number of heat generation elements 5 to obtain the heat dissipation requirement level of heat generation elements 5.

[0092] It can be understood that the ratio of heating power to heat conduction power is the first ratio. The physical meaning of the first ratio can be expressed as the heating element 5 requiring N heat conduction films 21 for heat conduction. N is the first ratio. However, there cannot be only one heating element 5 on the PCB. If there are M heating elements 5 on the PCB, and it is assumed that the heat output of all heating elements 5 is the same, then on average, a total of N×M heat conduction films 21 are needed for heat conduction. Therefore, the first ratio is multiplied by the total number of heating elements 5 to obtain the heat dissipation requirement level of the heating element 5. At this time, the physical meaning of the heat dissipation requirement level can be expressed as the heating element 5 needing to be connected to X heat conduction films 21. X is the heat dissipation requirement level.

[0093] This setting clarifies the physical meaning of the heat dissipation requirement level, making the size of the heat dissipation requirement level of the heat-generating element 5 equivalent to the number of connected heat-conducting films 21, which is beneficial for subsequently determining the depth of the heat-conducting holes of the first category of heat-conducting elements 41.

[0094] Furthermore, based on the heat dissipation requirements of heat-generating element 5, the category of the heat-conducting element is determined, including:

[0095] S630, when the heat dissipation requirement of the heat-generating element 5 is greater than the number of heat-conducting films 21, the category of the heat-conducting element is the second category heat-conducting element 42; otherwise, the category of the heat-conducting element is the first category heat-conducting element 41.

[0096] It can be understood that the physical meaning of the heat dissipation requirement level can be expressed as the heat-generating element 5 needing to be connected to X thermal conductive films 21. Therefore, when the heat dissipation requirement level of the heat-generating element 5 is greater than the number of PCB thermal conductive films 21, through holes and second-category thermal conductive elements 42 can be used to conduct heat for the heat-generating element 5. When the heat dissipation requirement level of the heat-generating element 5 is less than the number of PCB thermal conductive films 21, first-category thermal conductive elements 41 and blind holes are used directly to conduct heat for the heat-generating element 5.

[0097] This design not only provides sufficient heat conduction efficiency for each heat-generating element 5, but also reduces the number of through holes, maximizing the saving of wiring space on the PCB.

[0098] In S700, when the heat-conducting element is a first-category heat-conducting element 41, a blind slot is opened on the component side of the PCB board body 100, the first-category heat-conducting element 41 is filled into the blind slot, and then a heat-conducting hole is opened downward from the internal space of the first-category heat-conducting element 41, and copper is deposited in the heat-conducting hole to obtain a second copper deposit 62. Among them, the heat-conducting hole is a blind hole, and the heat-conducting hole passes through at least one layer of heat-conducting film 21. The depth of the heat-conducting hole is proportional to the heat dissipation requirement level.

[0099] Understandable, such as Figure 1 and Figure 2 As shown, the heat dissipation method of the first type of heat-conducting element 41 in conjunction with blind vias is as follows: First, a blind slot is opened on the component side of the PCB board body 100. The depth of the blind slot can be fixed. Specifically, the depth can be the depth through a layer of sandwich insulation layer 2. Then, the first type of heat-conducting element 41 is filled into the blind slot. Then, heat-conducting holes are opened from the hollow part of the first type of heat-conducting element 41 downwards. The heat-conducting holes pass through at least one layer of heat-conducting film 21. Moreover, the depth of the heat-conducting holes is proportional to the heat dissipation requirements of the heat-generating element 5. After the heat-conducting holes are opened, copper is deposited into the heat-conducting holes to obtain a second copper deposit 62. The second copper deposit 62 allows the first type of heat-conducting element 41 and multiple heat-conducting films 21 to be thermally and electrically connected together. Therefore, the heat of the heat-generating element 5 is transferred from multiple heat-conducting films 21 to the first copper deposit 61.

[0100] S800, when the heat-conducting element is the second type of heat-conducting element 42, a first through hole is opened on the PCB board body 100, and copper is deposited in the first through hole to obtain the second copper deposit 62, and then the second type of heat-conducting element 42 is filled into the first through hole.

[0101] like Figure 1 and Figure 3As shown, the heat dissipation method of the second type of heat-conducting element 42 in conjunction with the through hole is as follows: a first through hole is opened on the PCB board body 100, and then copper is deposited in the first through hole to form a second copper deposit 62. The second copper deposit 62 is thermally and electrically connected to all the heat-conducting films 21. Then, the second type of heat-conducting element 42 is filled into the first through hole. The second type of heat-conducting element 42 is tightly attached to the second copper deposit 62, and the second type of heat-conducting element 42 can be screw-shaped to further enhance the fit. Finally, a heat dissipation element 7 is welded to the bottom of the second type of heat-conducting element 42, so that the heat of the heat-generating element 5 can not only flow from the heat-conducting film 21 to the first copper deposit 61, but also be quickly dissipated through the heat dissipation element 7.

[0102] This setup allows for the manufacture of two types of thermally conductive components and corresponding multilayer PCBs.

[0103] Optionally, before stacking the core insulation layer 2 and the substrate layer 3, blind holes or through holes are drilled on the corresponding core insulation layer 2 and substrate layer 3, and then the core insulation layer 2 and substrate layer 3 are stacked in sequence.

[0104] It can be connected. Before stacking the core insulation layer 2 and the substrate layer 3, blind holes or through holes can be drilled on the corresponding numbered core insulation layer 2 and substrate layer 3. Then, the core insulation layer 2 and substrate layer 3 are stacked in sequence. After the stacking is completed, the blind holes or through holes can be polished multiple times to make the inner wall of the blind holes or through holes smoother.

[0105] This design prevents waste from accumulating inside the hole during drilling, thus reducing the surface quality of the hole's inner wall.

[0106] S900, solder mask layers are set on the upper and lower surfaces of the PCB board body 100, and then copper plating is performed on the side to obtain the first copper plating 61.

[0107] It is understandable that after drilling, a solder mask layer is laid on the double-sided circuit layer 1 to prevent the soldering process from damaging the circuit layer 1. Then, copper is deposited on the side of the PCB board body 100 to obtain the first copper deposit 61.

[0108] This design prevents damage to the circuit layer 1 during the soldering process and also prevents the first copper plating 61 from being electrically connected to the circuit layer 1 during the copper plating process on the side of the PCB100, which could lead to a short circuit or grounding of the circuit layer 1.

[0109] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0110] This application also provides a high thermal conductivity, low loss multilayer PCB fabrication equipment for new energy vehicles, used to fabricate the high thermal conductivity, low loss multilayer PCB for new energy vehicles described in any of the above embodiments.

[0111] For example, equipment for manufacturing high thermal conductivity, low loss multilayer PCBs for new energy vehicles can include etching equipment, lamination equipment, hole-punching equipment, copper plating equipment, soldering equipment, and control equipment. The etching equipment can be a common PCB etching machine, the lamination equipment can be a common PCB lamination machine, the hole-punching equipment can be a CNC machine tool or a PCB-specific drilling machine, the copper plating equipment can be a common PCB copper plating machine, and the soldering equipment can be an automatic component soldering machine. The control equipment can control the etching equipment to etch the corresponding circuits, control the lamination equipment to laminate the sandwich insulating layer and substrate layer, determine the type of thermally conductive component based on the heat dissipation requirements of the heat-generating components, control the hole-punching equipment to drill blind or through holes on the PCB, control the copper plating equipment to deposit copper on the PCB, and control the soldering equipment to automatically solder components on the PCB.

[0112] For example, control manufacturing can be microcontrollers, mobile phones, tablets, laptops, ultra-mobile personal computers (UMPCs), netbooks, desktop computers, computers, laptops, etc.

[0113] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A high thermal conductivity, low loss multilayer PCB for new energy vehicles, characterized in that, include: The PCB board body includes a circuit layer, a core insulating layer, and a substrate layer. The core insulating layer is disposed between the circuit layer and the substrate layer, and at least two core insulating layers are respectively located on opposite sides of the substrate layer. The core insulating layer includes a thermally conductive insulating adhesive and a thermally conductive film. The thermally conductive film is sandwiched within the thermally conductive insulating adhesive, and the edges of the thermally conductive film protrude from the sides of the thermally conductive insulating adhesive. The first copper plating covers the side of the PCB board body, and the first copper plating and the thermally conductive film of each of the sandwich insulation layers form a shielding space. Second copper plating; A thermally conductive element is embedded in the PCB board body and is connected to at least one layer of the thermally conductive film via a second copper plating. The top of the thermally conductive element is exposed above the circuit layer for soldering to a heat-generating element. The thermally conductive element can be either a first-type or a second-type element. The first-type element is a cylindrical structure embedded in a blind hole in the PCB body, and its inner wall is connected to at least one layer of the thermally conductive film via a second copper plating. The second-type element is a solid columnar element embedded in a through-hole in the PCB body, and its outer wall is connected to all the thermally conductive films via the second copper plating. The bottom of the second-type element is used for soldering to a heat-dissipating element. The method for preparing the sandwich insulation layer includes: A roll of thermally conductive material is provided, from which a thermally conductive material film is released and passed through an insulating adhesive pool, so that both sides of the thermally conductive material film are uniformly impregnated with thermally conductive insulating adhesive; wherein, the thermally conductive material film is a copper film or an aluminum film; The thermally conductive material film is passed through a scraping device to remove excess thermally conductive insulating adhesive, and then semi-cured and cut to a fixed size to obtain a sandwich insulating sheet. Based on the first shape of the PCB board body, the sandwich insulating sheet is cut into a second shape. Then, the thermally conductive insulating adhesive of the cut sandwich insulating sheet is liquefied by heating. A fixed depth of thermally conductive insulating adhesive is scraped off the edge of the sandwich insulating sheet, so that the part of the sandwich insulating sheet with thermally conductive insulating adhesive is in the first shape, thus obtaining the sandwich insulating layer. The first shape is the shape of the projection of the PCB board body on a set plane, and the second shape is the shape of the projection of the sandwich insulating sheet on the set plane. The set plane is perpendicular to the stacking direction of the thermally conductive insulating adhesive and the thermally conductive material film. The second shape is a similar shape to the first shape, and the area of ​​the second shape is larger than the area of ​​the first shape.

2. The high thermal conductivity, low loss multilayer PCB for new energy vehicles as described in claim 1, characterized in that, The outer wall of the second type of thermal conductive element is threaded, and the second type of thermal conductive element is connected to the second plating copper through the thread.

3. The high thermal conductivity, low loss multilayer PCB for new energy vehicles as described in claim 1, characterized in that, The second type of thermal conductive element includes a thermal conductive element body and a nut. The nut is connected to the top of the thermal conductive element body, and the outer side wall of the thermal conductive element body is threaded. The nut is used to separate from the thermal conductive element body after the thermal conductive element body is connected to the second copper plating through the thread.

4. The high thermal conductivity, low loss multilayer PCB for new energy vehicles as described in claim 1, characterized in that, All of the thermal conductive films are grounded.

5. The high thermal conductivity, low loss multilayer PCB for new energy vehicles as described in claim 1, characterized in that, The heat-conducting element is made of copper, copper alloy, aluminum, or aluminum alloy; The substrate layer is an aluminum substrate.

6. A method for preparing a sandwich insulation layer, used to manufacture the sandwich insulation layer as described in claim 1, characterized in that, The method for preparing the sandwich insulation layer includes: A roll of thermally conductive material is provided, from which a thermally conductive material film is released and passed through an insulating adhesive pool, so that both sides of the thermally conductive material film are uniformly impregnated with thermally conductive insulating adhesive; wherein, the thermally conductive material film is a copper film or an aluminum film; The thermally conductive material film is passed through a scraping device to remove excess thermally conductive insulating adhesive, and then semi-cured and cut to a fixed size to obtain a sandwich insulating sheet. Based on the first shape of the PCB board body, the sandwich insulating sheet is cut into a second shape. Then, the thermally conductive insulating adhesive of the cut sandwich insulating sheet is liquefied by heating. A fixed depth of thermally conductive insulating adhesive is scraped off the edge of the sandwich insulating sheet, so that the part of the sandwich insulating sheet with thermally conductive insulating adhesive is in the first shape, thus obtaining the sandwich insulating layer. The first shape is the shape of the projection of the PCB board body on a set plane, and the second shape is the shape of the projection of the sandwich insulating sheet on the set plane. The set plane is perpendicular to the stacking direction of the thermally conductive insulating adhesive and the thermally conductive material film. The second shape is a similar shape to the first shape, and the area of ​​the second shape is larger than the area of ​​the first shape.

7. A fabrication process for a high thermal conductivity, low loss multilayer PCB for new energy vehicles, used to manufacture the high thermal conductivity, low loss multilayer PCB for new energy vehicles as described in any one of claims 1 to 5, characterized in that, The fabrication process for high thermal conductivity and low loss multilayer PCBs used in new energy vehicles includes: The sandwich insulating layer and the substrate layer are provided in corresponding shapes and quantities, and the two sides of the substrate layer are chemically etched to form a circuit according to the circuit design. The core insulating layer and the substrate layer are stacked sequentially, and copper plating and chemical etching are performed on the upper and lower surfaces of the board layer formed after stacking the core insulating layer and the substrate layer to obtain the circuit layer, so as to obtain the PCB board body. The category of the heat-conducting element is determined according to the heat dissipation requirement level of the heat-generating element; When the heat-conducting element is the first type of heat-conducting element, a blind slot is opened on the component side of the PCB board body, the first type of heat-conducting element is filled in the blind slot, and then a heat-conducting hole is opened downward from the internal space of the first type of heat-conducting element, and copper is deposited in the heat-conducting hole to obtain the second copper plating; wherein, the heat-conducting hole is a blind hole, the heat-conducting hole passes through at least one layer of the heat-conducting film, and the depth of the heat-conducting hole is proportional to the heat dissipation requirement level; When the heat-conducting element is the second type of heat-conducting element, a first through hole is opened on the PCB board body, and copper plating is performed in the first through hole to obtain the second type of copper plating, and then the second type of heat-conducting element is filled into the first through hole. Solder resist layers are applied to the top and bottom surfaces of the PCB board body, and then copper plating is applied to the sides to obtain the first copper plating.

8. The fabrication process of high thermal conductivity and low loss multilayer PCB for new energy vehicles as described in claim 7, characterized in that, Determining the heat dissipation requirement level of the heat-generating element includes: Obtain the heating power and total number of the heating elements, and then obtain the thermal conductivity of a single thermal conductive film; Divide the heating power by the thermal conductivity to obtain a first ratio, and then multiply the first ratio by the total number of heating elements to obtain the heat dissipation requirement level of the heating elements.

9. The fabrication process of high thermal conductivity and low loss multilayer PCB for new energy vehicles as described in claim 8, characterized in that, The step of determining the category of the heat-conducting element based on the heat dissipation requirement level of the heat-generating element includes: When the heat dissipation requirement of the heat-generating element is greater than the number of thermal conductive films, the category of the thermal conductive element is determined to be the second category of thermal conductive element; otherwise, the category of the thermal conductive element is determined to be the first category of thermal conductive element.

10. A high thermal conductivity, low loss multilayer PCB fabrication equipment for new energy vehicles, characterized in that, Used to prepare high thermal conductivity and low loss multilayer PCB for new energy vehicles as described in any one of claims 1 to 5.

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