A new energy vehicle sensor circuit board assembly

Abstract

The present application relates to the technical field of circuit board, in particular to a new energy automobile sensor circuit board assembly, comprising: a flexible substrate, the flexible substrate is configured to include a tensile wire, a conductive element and a flexible film structure, the flexible film structure covers the tensile wire and the conductive element; a plurality of discrete hard component welding islands distributed, connected to the first surface and / or the second surface of the flexible substrate. The circuit board assembly of the application realizes the limit adaptation of space by the cooperation of the flexible substrate and the hard component welding island, the rigid carrier of the hard island area ensures the reliability of chip welding, and the flexible matrix embedded with aramid fiber can avoid the deformation stress of the wire, so that the circuit board can be attached to the special-shaped cavity without damaging the electrical connection, and the two layers of glue layers arranged outside the chip can maintain good heat dissipation and anti-vibration performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit boards, in particular to a new energy automobile sensor circuit board assembly. BACKGROUND

[0002] With the rapid popularization of new energy automobile 800V high-voltage architecture, the internal high-voltage connector needs to integrate temperature, impedance and other multi-parameter monitoring circuits, and the circuit board must be in a millimeter-level special-shaped cavity, considering high-density wiring, chip reliable installation and extreme working condition resistance. In the current mainstream scheme, the rigid segmented circuit is difficult to adapt to the curved cavity structure due to physical size limitations, and the connection part is prone to fatigue failure under mechanical vibration working conditions; while the pure flexible circuit has deformation ability, but the mechanical stability of the key component welding area is insufficient, and repeated deformation may lead to a decrease in electrical connection reliability. In addition, single-layer sealing materials are prone to produce bubbles when filling complex micro-gaps, affecting the uniformity of heat dissipation, and the interface adhesion force decays significantly after long-term thermal cycling.

[0003] As described above, the existing circuit architecture faces the challenge of multi-physical field coupling: the mechanical properties of the substrate are difficult to balance local rigid support and overall deformation adaptability; the sealing process is difficult to achieve defect-free filling at the sub-millimeter scale, limiting the thermal management efficiency; there is a design contradiction between the impedance stability and the mechanical impact resistance of the conductive circuit under dynamic working conditions.

[0004] These factors jointly restrict the long-term reliability of the monitoring circuit in the high-voltage connector in extreme temperature, vibration and electromagnetic interference environments, and the industry urgently needs to break through the limitations of traditional single material system. SUMMARY

[0005] In view of the technical problems existing in the prior art circuit board, the present application provides a new energy automobile sensor circuit board assembly, comprising:

[0006] A flexible substrate, the flexible substrate is configured to include a tensile wire, a conductive element, and a flexible film structure covering the tensile wire and the conductive element;

[0007] A plurality of discrete hard component welding islands connected to the first surface and / or the second surface of the flexible substrate, each of the hard component welding islands is used to carry a target component, and a gap region is formed between two adjacent hard component welding islands;

[0008] Wherein, in the gap region, the conductive element is distributed in a serpentine shape, and both ends of the conductive element are electrically connected to the hard component welding islands, respectively, for realizing electrical connection between the target components carried on the two adjacent hard component welding islands, and the tensile wire is connected to the two adjacent hard component welding islands.

[0009] A bonding area is formed between adjacent regions of the plurality of gap regions, and an opening is provided in the bonding area, the opening penetrating through the first surface and the second surface of the flexible substrate.

[0010] Preferably, the tensile wire includes aramid fiber tows distributed along the shortest path between adjacent hard component welding islands, and the conductive element includes a metal wire or a metal foil, and the length of the conductive element is more than 130% of the length of the aramid fiber tows in the same gap region.

[0011] Preferably, the flexible film structure includes a polyimide film, a wiring layer is formed by the tensile wire and the conductive element, and the polyimide film is at least wrapped around the outer layer of the wiring layer in the gap region.

[0012] Preferably, the hard component welding island includes a high-frequency FR4 substrate, an edge of the high-frequency FR4 substrate is provided with an edge sealing structure, and the aramid fiber tows are connected to the edge sealing structure.

[0013] Preferably, the edge sealing structure includes a copper edge sealing structure, and the contact surface between the edge sealing structure and the high-frequency FR4 substrate is a sawtooth surface.

[0014] Preferably, the surface of the hard component welding island is provided with a packaging area carrying a target component, a first encapsulation layer completely covering the packaging area is arranged on the hard component welding island, a second encapsulation layer is arranged on the outer layer of the first encapsulation layer, and the hardness of the first encapsulation layer is greater than that of the second encapsulation layer.

[0015] Preferably, the first encapsulation layer is configured in a frustum structure, the second encapsulation layer is of equal thickness and at least covers the side wall of the first encapsulation layer, and the axis of the first encapsulation layer is perpendicular to the surface of the hard component welding island.

[0016] Preferably, the side wall of the first encapsulation layer has an inclination angle of 45° to 60°, the first encapsulation layer includes a silicone rubber structure layer filled with thermally conductive particles, and the second encapsulation layer includes a bubble structure layer.

[0017] Preferably, the area of the opening accounts for 8% to 12% of the total area of the flexible substrate.

[0018] Preferably, the plurality of hard component welding islands are distributed in a matrix, the hard component welding islands are rectangular or circular, or the plurality of hard component welding islands are distributed in a honeycomb shape, and each hard component welding island is hexagonal or circular.

[0019] Compared with the prior art, the application has the following advantages:

[0020] The circuit board assembly of the present application realizes the limit adaptation of space through the cooperation of the flexible substrate and the hard component welding island, the rigid island area ensures the reliability of chip welding with the rigid carrier, and the flexible substrate embedded with aramid fiber can avoid the deformation stress of the wire, so that the circuit board can be attached to the special-shaped cavity without damaging the electrical connection, and the two layers of glue sealing layers arranged outside the chip can maintain good heat dissipation and anti-vibration performance, the distributed hard island layout and staggered holes synergistically optimize the mechanical strength and glue filling channel, which can adapt to complex and small cavities, and still meet the needs of anti-vibration, heat cycle resistance and high pressure isolation under the condition of maintaining ultra-thin shape. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures can be represented by a like numeral. For purposes of clarity, not every component can be called out in every drawing. Embodiments of various aspects of the present application will now be described, by way of example only, with reference to the drawings in which:

[0022] Figure 1 is a schematic diagram of the existing circuit board installed in a small space;

[0023] Figure 2 is a schematic diagram of the new energy vehicle sensor circuit board assembly shown in the present application installed in a small space;

[0024] Figure 3 is a structural schematic diagram of the new energy vehicle sensor circuit board assembly shown in the present application;

[0025] Figure 4 is a distribution schematic diagram of the tensioning material and the conductive element shown in the present application;

[0026] Figure 5 is a structural schematic diagram of the outer glue sealing layer of the hard component welding island shown in the present application. DETAILED DESCRIPTION

[0027] In order to better understand the technical content of the present application, specific embodiments are described below with reference to the accompanying drawings.

[0028] As shown in Figure 1 , when facing the installation of a small space, the maximum size L2 of the smallest space determines the maximum size of the circuit board L1, and when the installation space is irregularly shaped, it is more difficult to match the size of the circuit board, for example, the existing rigid PCB board cannot adapt to the curved cavity of less than 5mm in the fast charging gun head, and although the flexible circuit board can be bent to fit the cavity, the welding points are easy to deform or even fall off under bending stress.

[0029] Therefore, the present application aims to propose a sensor circuit board assembly with rigidity and flexibility, as Figure 2As shown, the sensor circuit board assembly can be bent and folded along with the shape of the cavity, but the mounting area of the target component 50 is a hard structure, which will not cause the solder joints to fall off due to stress, and the actual unfolded size of the circuit board can be larger than the mounting size L3, so that the circuit board assembly can be in a compressed state during installation, and the outer contour L4 can be smaller than L3 for installation, meeting the rigid requirements of chip installation in a millimeter-level special-shaped space and the cavity deformation following ability.

[0030] As shown in the Figures 3 to 5 The present application provides a new energy vehicle sensor circuit board assembly, mainly including a flexible substrate 102 and a plurality of discrete distributed hard component welding islands 101 arranged on the flexible substrate 102.

[0031] The flexible substrate 102 is configured to include a tensile wire 31, a conductive element 32, and a flexible film structure, wherein the flexible film structure covers the tensile wire 31 and the conductive element 32. A plurality of discrete distributed hard component welding islands 101 are connected to the first surface and / or the second surface of the flexible substrate 102, wherein each hard component welding island 101 is used to mount a target component 50, and a gap area 103 is formed between two adjacent hard component welding islands 101.

[0032] In this way, the hard component welding island 101 can provide a hard load area for the target component 50, and compared with the flexible circuit board, under the stress caused by bending and extrusion, the solder joints of the target component 50 are less likely to be de-soldered, and at the same time, the flexible film structure can provide flexible connection between adjacent hard component welding islands 101, so that adjacent hard component welding islands 101 can be distributed in a smaller position according to the actual installation space, such as a suitable folding and bending state.

[0033] Further, at the gap area 103, the conductive element 32 is in a serpentine distribution, and the two ends of the conductive element 32 are respectively electrically connected to the hard component welding islands 101, for realizing electrical connection between the target components 50 mounted on the two adjacent hard component welding islands 101, and the tensile wire 31 is connected to the two adjacent hard component welding islands 101.

[0034] In this way, the tensile wire 31 bears the tensile stress between the two hard component welding islands 101, ensuring that the structure will not separate from each other, and the conductive element 32 is in a serpentine distribution, which can effectively avoid the pulling and breaking caused by bending and twisting, and ensure the reliability of electrical signal transmission.

[0035] In an optional embodiment, the tension filament 31 comprises aramid filament bundles distributed along the shortest path between adjacent rigid component welding islands 101, and the conductive element 32 comprises metal wires or metal foils, such as copper wires or copper foils, etc., and the length of the conductive element 32 in the same gap region 103 is more than 130% of the length of the aramid filament bundles.

[0036] Thus, by using aramid filament bundles to limit the gap length between the two rigid component welding islands 101, the conductive element 32 is prevented from being stretched.

[0037] like Figure 5 As shown, in the above embodiments, the flexible coating structure can be selected as a polyimide film 20, which is composed of a tension filament 31 and a conductive element 32 to form a wiring layer 30. The polyimide film 20 covers the outer layer of the wiring layer 30 at least in the gap region 103.

[0038] In the gap region 103, the wiring layer 30 structure (bearing filament 31 and conductive element 32) is always covered by the polyimide film 20 to prevent it from being exposed and to protect the wiring layer 30 structure. The polyimide film 20 has extreme temperature resistance and can meet the requirement of 150°C high temperature peak for fast charging. At the same time, the polyimide film 20 has good elongation at break and can be used with aramid filament bundles to withstand bending.

[0039] In an optional embodiment, a thermally conductive silicone layer 10 is disposed on the bottom layer of the polyimide film 20 to provide protection and thermal conductivity.

[0040] Furthermore, the rigid component welding island 101 includes a high-frequency FR4 substrate 40, the edge of which is provided with an edge sealing structure, and aramid filament bundles are connected to the edge sealing structure.

[0041] Among them, the high-frequency FR4 substrate 40 has the characteristics of high frequency and low loss, and has high bending strength, which can provide compressive support.

[0042] Thus, by fixing the aramid fiber bundles with the high-frequency FR4 substrate 40 through edge sealing structure and high-temperature pressing, the integrity of the structural connection can be effectively improved.

[0043] Optionally, the edge sealing structure includes a copper edge sealing structure, and the contact surface between the edge sealing structure and the high-frequency FR4 substrate 40 is a serrated surface. The serrated surface effectively improves the connection strength of the aramid fiber bundles.

[0044] Combination Figure 4 and Figure 5As shown, the surface of the rigid component soldering island 101 is provided with an encapsulation area 105 for mounting the target component 50. The rigid component soldering island 101 is provided with a first encapsulation layer 60 that completely covers the encapsulation area 105. A second encapsulation layer 70 is provided on the outer layer of the first encapsulation layer 60. The hardness of the first encapsulation layer 60 is greater than the hardness of the second encapsulation layer 70.

[0045] The first sealant layer 60 is designed to protect the target electrical component in the encapsulation area 105 and improve the outward heat diffusion capability of the electrical component through complete adhesion, while the second sealant layer 70 is designed to achieve vibration damping.

[0046] In an optional embodiment, the first sealant layer 60 is configured as a frustum-shaped structure, and the second sealant layer 70 covers at least the sidewall of the first sealant layer 60 with an equal thickness, the axis of the first sealant layer 60 being perpendicular to the surface of the hard component solder island 101.

[0047] Specifically, the sidewall inclination angle of the first sealant layer 60 is 45°~60°, and the first sealant layer 60 includes a silicone rubber structural layer filled with thermally conductive particles, such as graphene or boron nitride particles filled in the silicone rubber structural layer, and the second sealant layer 70 includes a bubble structural layer.

[0048] Thus, the placement of heat-conducting particles facilitates the transfer of heat from components to the outside.

[0049] like Figure 4 Figure 5 As shown, a bonding region 104 is formed in the adjacent areas of multiple gap regions 103. An opening 80 is provided in the bonding region 104, and the opening 80 penetrates the first surface and the second surface of the flexible substrate 102.

[0050] Thus, by using the 80-degree opening design, after the circuit board assembly is filled into the predetermined installation space, it is beneficial to fill the entire space with structural adhesive during the potting process, avoiding the formation of air gaps and improving heat dissipation capacity.

[0051] Optionally, the area of ​​the opening 80 accounts for 8% to 12% of the total area of ​​the flexible substrate 102. If the opening is too small, air bubbles are likely to remain during the potting process, while if the opening is too large, it will reduce the strength of the structure.

[0052] In the above embodiments, multiple hard component welding islands 101 are distributed in a matrix, and the hard component welding islands 101 are rectangular or circular.

[0053] In other embodiments, multiple hard component soldering islands 101 are distributed in a honeycomb pattern, and each hard component soldering island 101 is hexagonal or circular.

[0054] In an optional embodiment, the size of the rigid component welding island 101 is 0.5 mm larger than the target electrical component. The spacing between the rigid component welding islands 101 can be adjusted according to the shape and curvature of the space to be installed, and is approximately 1.5~2 mm. The thickness of the polyimide film 20 is approximately 50 micrometers, wherein the diameter of the aramid filament bundle is 20 micrometers. The aramid filament bundle can be laser welded to the connection surface of the copper block and the high-frequency FR4 substrate 40.

[0055] In conjunction with the above embodiments, the circuit board assembly of this application achieves extreme spatial adaptation through the combination of flexible substrate and rigid component soldering islands. The rigid island area ensures the reliability of chip soldering with a rigid carrier, while the flexible substrate embedded with aramid fibers can avoid deformation stress on the wires, allowing the circuit board to fit into irregularly shaped cavities without damaging electrical connections. The two layers of encapsulation arranged sequentially outside the chip can maintain good heat dissipation and vibration resistance. The distributed rigid island layout and staggered openings synergistically optimize mechanical strength and potting channels, which can adapt to complex and narrow cavities and still meet the requirements of vibration resistance, heat cycle resistance and high voltage isolation while maintaining an ultra-thin shape.

[0056] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A sensor circuit board assembly for new energy vehicles, characterized in that, include: A flexible substrate (102) is configured to include a tensile filament (31), a conductive element (32), and a flexible coating structure covering the tensile filament (31) and the conductive element (32). Multiple discretely distributed rigid component welding islands (101) are connected to the first and / or second surfaces of the flexible substrate (102), each of the rigid component welding islands (101) is used to mount a target component (50), and a gap region (103) is formed between two adjacent rigid component welding islands (101). In the gap region (103), the conductive element (32) is distributed in a serpentine pattern, and the two ends of the conductive element (32) are electrically connected to the rigid component welding island (101) respectively, so as to realize the electrical connection between the target components (50) mounted on the two adjacent rigid component welding islands (101), and the bearing wire (31) is connected to the two adjacent rigid component welding islands (101). A bonding area (104) is formed in adjacent areas of the plurality of gap areas (103), and an opening (80) is provided in the bonding area (104), the opening (80) penetrating the first surface and the second surface of the flexible substrate (102).

2. The sensor circuit board assembly for new energy vehicles according to claim 1, characterized in that, The bearing filament (31) comprises aramid filament bundles distributed along the shortest path between adjacent rigid component welding islands (101), and the conductive element (32) comprises metal wire or metal foil, wherein the length of the conductive element (32) in the same gap region (103) is more than 130% of the length of the aramid filament bundle.

3. The new energy vehicle sensor circuit board assembly according to claim 1, characterized in that, The flexible coating structure includes a polyimide film (20), and a wiring layer (30) is formed by the tension filament (31) and the conductive element (32). The polyimide film (20) covers the outer layer of the wiring layer (30) at least in the gap region (103).

4. A new energy vehicle sensor circuit board assembly according to claim 2, characterized in that, The rigid component welding island (101) includes a high-frequency FR4 substrate (40), the edge of which is provided with a sealing structure, and the aramid filament bundle is connected to the sealing structure.

5. A new energy vehicle sensor circuit board assembly according to claim 4, characterized in that, The edge sealing structure includes a copper edge sealing structure, and the contact surface between the edge sealing structure and the high-frequency FR4 substrate (40) is a serrated surface.

6. A sensor circuit board assembly for new energy vehicles according to claim 1, characterized in that, The surface of the rigid component soldering island (101) is provided with an encapsulation area (105) for mounting the target component (50). The rigid component soldering island (101) is provided with a first sealing layer (60) that completely covers the encapsulation area (105). A second sealing layer (70) is provided on the outer layer of the first sealing layer (60). The hardness of the first sealing layer (60) is greater than the hardness of the second sealing layer (70).

7. A new energy vehicle sensor circuit board assembly according to claim 6, characterized in that, The first sealant layer (60) is configured as a frustum-shaped structure, and the second sealant layer (70) of equal thickness covers at least the sidewall of the first sealant layer (60), with the axis of the first sealant layer (60) perpendicular to the surface of the hard component solder island (101).

8. A sensor circuit board assembly for a new energy vehicle according to claim 6, characterized in that, The first sealant layer (60) has a sidewall inclination angle of 45°~60°. The first sealant layer (60) includes a silicone rubber structural layer filled with thermally conductive particles. The second sealant layer (70) includes a bubble structural layer.

9. A sensor circuit board assembly for new energy vehicles according to claim 1, characterized in that, The area of ​​the opening (80) accounts for 8% to 12% of the total area of ​​the flexible substrate (102).

10. A new energy vehicle sensor circuit board assembly according to any one of claims 1-9, characterized in that, Multiple hard component welding islands (101) are arranged in a matrix, and the hard component welding islands (101) are rectangular or circular, or multiple hard component welding islands (101) are arranged in a honeycomb pattern, and each hard component welding island (101) is hexagonal or circular.

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