Manufacturing method for voltage-resistant flexible circuit board for new energy vehicles

Abstract

The present invention discloses a method for manufacturing a voltage-resistant flexible circuit board for new energy vehicles, comprising the steps of: taking a copper foil; taking a single-sided flexible copper-clad laminate having a structure in which a PI layer, an adhesive layer, and a copper layer are sequentially laminated; laminating the copper foil and the single-sided flexible copper-clad laminate and pressing them together to form a flexible pressure-welded plate; fabricating a circuit on the copper foil of the flexible pressure-welded plate; removing the copper layer to form a flexible core substrate; taking a first coating film and a second coating film; sequentially laminating the first coating film, the flexible core substrate, and the second coating film and pressing them together to form the pressure-welded plate; and attaching a stiffener to the pressure-welded plate to form a flexible circuit board. The single-sided copper-clad laminate is formed by transfer printing and does not have an adhesive layer, which has higher voltage resistance. The ground lines are designed to be connected to the stiffener via a conductive adhesive, thereby realizing a ground line network. This avoids the relatively unreliable and less applicable method of connecting the ground lines to a ground module by welding, and forms a flow-process manufacturing method overall, which has good synergy.

Description

[Technical Field]

[0001] The present invention relates to the field of processing printed circuit boards, in particular to the field of processing flexible circuit boards, and more particularly to a method for manufacturing voltage-resistant flexible circuit boards for new energy vehicles. [Background technology]

[0002] As new energy vehicles continue to develop, their intelligence, multi-functionality, and network connection performance are constantly improving, and some control units are required to have relatively high voltage resistance and grounding performance. As control unit modules become increasingly miniaturized, internal circuit boards are required to achieve flexible distribution in relatively small spaces. Therefore, flexible circuit boards using single-layer copper wiring have emerged to replace traditional connecting wire harnesses, achieving flexible installation and relatively good voltage resistance and grounding performance.

[0003] Currently, such flexible circuit boards are manufactured using conventional manufacturing methods, namely, a single-sided flexible copper-clad laminate with a relatively thick copper layer is taken, a core substrate is made, and a voltage-resistant line and a ground line are formed. Then, other layers are laminated, pressure-welded, and processed through post-processing to form a flexible circuit board. The relatively thick copper layer lines achieve relatively high voltage resistance, and the ground lines are subsequently welded to the ground component of the electronic module to provide good grounding properties.

[0004] However, this manufacturing method has the following main problems: In a typical single-sided flexible copper-clad laminate, an adhesive layer is placed between the copper layer and the polyimide material layer, and the pressed coating layer also has an adhesive layer, so that the copper layer of the line after pressing is covered by two adhesive layers, one above the other. The adhesive layers are generally epoxy resin adhesive layers or acrylic adhesive layers, and their glass transition temperatures are lower than those of polyimide materials, which are more advantageous for processes such as pressing flexible circuit board products and reduce processing difficulty. However, during the application of flexible circuit board products, problems such as poor voltage resistance and line burnout after long-term use are likely to occur. Meanwhile, the grounding method using welding of ground lines places relatively high requirements on subsequent processing, and flexible circuit boards are relatively soft, making welding more difficult and prone to a relatively high reject rate.

[0005] Based on the above background and problems, it is necessary to provide a new manufacturing method that improves the voltage resistance and grounding performance of flexible circuit boards. Summary of the Invention [Means for solving the problem]

[0006] The present invention provides a method for manufacturing a voltage-resistant flexible circuit board for new energy vehicles, in response to the problems that a flexible circuit board having a voltage-resistant line and a ground line has insufficient voltage-resistant performance and requires complicated ground design and grounding process, and the manufacturing method comprises: Step S10: taking a copper foil and a single-sided flexible copper-clad laminate having a structure in which a polyimide layer, an adhesive layer, and a copper layer are laminated in this order; and laminating and pressing the copper foil and the single-sided flexible copper-clad laminate together to form a flexible pressure-welded board. Step S20: forming a line on the copper foil of the flexible pressure-welded plate and removing the copper layer to form a flexible core substrate; Step S30 of removing the first covering film and the second covering film, sequentially stacking the first covering film, the flexible core substrate, and the second covering film, and pressing them together to form a pressure-welded plate; and step S40 of attaching a reinforcing material to the pressure-welding plate to form the flexible circuit board.

[0007] Furthermore, the step of forming the flexible pressure-welded plate includes the steps of attaching a high-temperature resistant blue solder mask to one side of the copper foil to form copper foil with a blue solder mask, performing a plasma activation process on the single-sided flexible copper-clad laminate and then performing a chemical activation process to form an activated copper-clad laminate, and laminating the copper foil with the blue solder mask and the activated copper-clad laminate, facing the copper foil to the polyimide layer and pressing them together to form the flexible pressure-welded plate.

[0008] Furthermore, the step of forming the flexible pressure-welded plate includes the steps of stacking the copper foil and the activated copper-clad laminate to form a laminated structure, and providing a release film, a coverlay film, a release film, an aluminum sheet, and a release film in that order on both sides of the laminated structure to form a surface-mounted structure and press the laminated structure together to form the flexible pressure-welded plate.

[0009] Furthermore, the step of forming the flexible core substrate includes the steps of fabricating the lines, including fabricating a voltage-resistant line and a ground line, and removing the copper layer, opening windows in the adhesive layer and the polyimide layer, forming window openings in the core substrate, and overall forming the flexible core substrate.

[0010] Furthermore, the step of forming the pressure-welded plate includes the steps of: creating a first window opening in the first coating film corresponding to the voltage-resistant line, and forming a first window-opening coating film; creating a second window opening in the second coating film corresponding to the window opening in the core substrate, and forming a second window-opening coating film; and sequentially stacking the first window-opening coating film, the flexible core substrate, and the second window-opening coating film, orienting the line toward the first window-opening coating film, and pressing them together to form the pressure-welded plate.

[0011] Furthermore, one side of the second window opening is larger than the window opening of the core substrate.

[0012] Furthermore, the step of forming the flexible circuit board includes a step of silk-printing a conductive adhesive on one surface of the second window-opening coating film of the pressure-welded plate, and then attaching and pressing the reinforcing material to form the flexible circuit board.

[0013] Furthermore, the reinforcing material is made of a metal material.

[0014] Furthermore, the second covering film covers the region of the voltage-resistant line.

[0015] Furthermore, the reinforcing material has a corrugated edge facing the inside of the flexible circuit board. [Effects of the Invention]

[0016] The technical solution of the present invention is to first carry out plasma activation on the single-sided copper clad laminate, then carry out chemical activation, and at the same time, attach a high-temperature resistant blue solder mask for transfer onto the copper foil, and realize interlayer transfer by pressure welding, thereby producing and forming a single-sided copper clad laminate without an adhesive layer, which provides a basis for a copper clad laminate with higher voltage resistance performance, and also increases the second window coating film, further improving the voltage resistance performance of the flexible circuit board and increasing the coating performance. The ground line is designed to be connected to the stiffener via conductive adhesive, thereby realizing the ground line networking process, avoiding the process of connecting the surface pad ground line to the ground module by welding, and improving the processability and application performance of the ground line. In addition, the manufacturing process is carried out by using the window part of the core substrate. and the second window opening, thereby achieving a process in which the conductive adhesive and the ground line form a good interconnection, effectively improving product reliability. The entire process forms an adhesive-free copper-clad laminate. Furthermore, a second window opening coating film is introduced to improve coating performance and voltage resistance. The ground line is designed to be interconnected with the stiffener via conductive adhesive, so the second window opening coating film affects the manufacturing process of the conductive adhesive and stiffener. Therefore, the window opening and the second window opening of the core substrate are designed to provide good window opening conditions for the manufacturing of the conductive adhesive. Furthermore, the network line is designed to improve the performance of the ground line bonding to the stiffener via conductive adhesive, thereby realizing synergy and correlation in the entire processing process and forming a well-flowed manufacturing method. [Brief explanation of the drawings]

[0017] In order to more clearly describe the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can obtain other drawings based on the structures shown in these drawings without any creative efforts.

[0018] [Figure 1]1 is a flowchart of the main processes involved in an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing a cross-sectional structure of the imposition structure of the present embodiment. [Figure 3] 1 is a diagram showing a cross-sectional structure of a flexible insulation displacement plate according to the present embodiment; [Figure 4] 1 is a diagram showing a cross-sectional structure of an imposition structure of a flexible substrate according to an embodiment of the present invention; [Figure 5] 3A and 3B are diagrams showing a cross-sectional structure of a pressure-welded plate according to the present embodiment; [Figure 6] FIG. 6 is a diagram showing the structure of a cross section AA in FIG. 5. [Figure 7] 1 is a diagram showing a cross-sectional structure of a flexible circuit board according to an embodiment of the present invention; [Figure 8] FIG. 2 is a plan design diagram of the meshed line of the present embodiment. [Figure 9] 10A and 10B are diagrams showing the cross-sectional structure of another pressure-welded plate according to the present embodiment. [Figure 10] FIG. 2 is a plan design diagram of the corrugated reinforcement material of this embodiment. [Figure 11] 11 is a diagram showing the cross-sectional structure of FIG. 10 taken along the line BB. [Figure 12] FIG. 10 is a diagram showing a cross-sectional structure of another flexible circuit board according to the present embodiment.

[0019] The realization of the objects, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the drawings. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, the technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments that can be obtained by those skilled in the art without any creative efforts belong to the scope of protection of the present invention.

[0021] In the embodiment of the present invention, all directional indications (e.g., up, down, left, right, front, back, back, outside, etc.) are used only to interpret the relative positional relationships and movement conditions between each component in a specific posture (as shown in the drawings), and when the specific posture changes, the directional indications also change accordingly.

[0022] It should also be understood that in the present invention, references to "first," "second," etc. are for descriptive purposes only and do not indicate or imply the relative importance or the number of technical features indicated. Thus, a feature qualified as "first" or "second" can explicitly or implicitly include at least one such feature. In the description of the present invention, unless otherwise specified, "plurality" means at least two, e.g., two, three, etc.

[0023] In addition, the technical solutions of each embodiment of the present invention can be combined with each other if it is possible for a person skilled in the art to realize it. If the combination of technical solutions is contradictory or not possible to realize, it should be considered that such combination of technical solutions does not exist and is not included in the scope of protection claimed by the present invention.

[0024] Please refer to Figure 1, which is a flow chart of the main processes involved in an embodiment of the present invention.

[0025] The manufacturing method of a voltage-resistant flexible circuit board for new energy vehicles according to an embodiment of the present invention includes the main manufacturing process flow shown in FIG. 1, which will be described in detail below in steps.

[0026] Please refer to Figures 2 and 3. Figure 2 is a diagram showing the cross-sectional structure of the imposition structure of this embodiment, and Figure 3 is a diagram showing the cross-sectional structure of the flexible pressure-displacement plate of this embodiment.

[0027] In step S10, The copper foil 110 is taken, and a single-sided flexible copper-clad laminate having a structure in which a polyimide layer 1310, an adhesive layer 1320, and a copper layer 1330 are sequentially laminated is taken, and the copper foil 110 and the single-sided flexible copper-clad laminate are laminated and pressed together to form a flexible pressure-welded plate 20.

[0028] Furthermore, the step of forming the flexible pressure-welded plate 20 includes the steps of attaching a high-temperature resistant blue solder mask 120 to one side of the copper foil 110 to form copper foil 1020 with the blue solder mask, performing a plasma activation process on the single-sided flexible copper-clad laminate and then performing a chemical activation process to form an activated copper-clad laminate 130, and laminating the copper foil 1020 with the blue solder mask and the activated copper-clad laminate 130, facing the copper foil 110 against the polyimide layer 1310 and pressing them together to form the flexible pressure-welded plate 20.

[0029] The thickness of the copper foil 110 is selectably between 35 μm and 245 μm, and the thicker it is, the greater the voltage it can withstand.

[0030] Optionally, the high temperature resistant blue solder mask 120 can withstand temperatures between 160°C and 220°C. The high temperature resistant blue solder mask 120 is an auxiliary transfer film used in the process, and can withstand the high temperature and high pressure pressure welding process in the subsequent process, while also being able to be peeled off smoothly.

[0031] Optionally, the copper foil 1020 with the blue solder mask may be subjected to micro-etching or ultra-roughening treatment, which allows the copper foil 110 to form a good bonding process and bond strength with the polyimide layer 1310 during the subsequent pressure bonding process, thereby avoiding problems such as incomplete bonding, separation, and voids.

[0032] Optionally, the plasma activation process is a suitable process using conventional plasma equipment and parameters to introduce hydroxyl groups (-OH) into the surface of the polyimide layer 1310, making the surface more hydrophilic.

[0033] Optionally, the chemical activation treatment is performed using the activation step in the conventional electroless copper plating processing line, which after plasma activation further improves the activation effect and uniform surface roughness of the polyimide layer 1310, and improves the hydrophilicity and activity of the surface.

[0034] The reason for adopting the method of performing plasma activation first and then chemical activation is that in this manufacturing method, an adhesive-free copper clad laminate is first produced and formed, which does not include an adhesive layer 1320 and is composed only of a polyimide layer 1310 and copper foil 110. However, since the polyimide layer 1310 is highly inert, it is generally difficult to bond to the copper foil 110 by pressure welding. Therefore, the polyimide layer 1310 must be sufficiently activated to give its surface good activity and uniform roughness, which effectively improves the pressure welding bonding strength with the copper foil 110, thereby forming an adhesive-free substrate and realizing an adhesive-free copper clad laminate with good bonding strength of interlayer peel strength > 15 N.

[0035] Furthermore, the step of forming the flexible pressure-welded plate 20 includes a step of laminating the copper foil 110 and the activated copper-clad laminate 130 to form a laminate structure 10A, and a step of providing a release film (each including the first release film 1410 and the fourth release film 1440 in FIG. 2 ), a coverlay film (each including the first coverlay film 1510 and the second coverlay film 1520 in FIG. 2 ), and a release film (each including the second release film 1410 and the fourth release film 1440 in FIG. 2 ) on both sides of the laminate structure 10A. 20 and fifth release film 1450), an aluminum sheet (including first aluminum sheet 1610 and second aluminum sheet 1620 in FIG. 2, respectively), and a release film (including third release film 1430 and sixth release film 1460 in FIG. 2, respectively) are arranged in close order to form an imposition structure 10, which is then placed between an upper table 1710 of a press machine and a lower table 1720 of the press machine and pressed to form a flexible pressing plate 20.

[0036] The release film can provide good release properties after pressure welding and can be made of polyimide or polytetrafluoroethylene. The cover layer film can provide effective buffering and heat conduction during the pressure welding process and can be made of materials such as silicone pad or kraft paper. The aluminum sheet has good flattening and heat conduction properties.

[0037] In this embodiment, a conventional single-sided flexible copper clad laminate and a single layer of copper foil 110 are joined by pressure welding, and a single-sided flexible copper clad laminate without an adhesive layer 1320 is formed using this film transfer processing method, which effectively improves the glass transition temperature, thermochemical properties, and tensile strength of the entire copper clad laminate, reduces the molding shrinkage rate, improves the overall performance of the material, and effectively avoids the impact of the adhesive layer in the single-sided copper clad laminate of the conventional technology on the voltage resistance performance of the flexible circuit board 60.

[0038] The maximum pressure for pressing the copper foil 1020 with the blue solder mask and the activated copper clad laminate 130 together in this embodiment is relatively large, and can be set to 18 kg / cm. 2 ~30kg / cm 2 The pressure bonding temperature is relatively high, preferably 160°C to 220°C, and the pressure bonding time under the maximum pressure condition is relatively long, preferably 15 minutes to 40 minutes, to ensure the formation of a good adhesive-free copper clad laminate material.

[0039] Please refer to Fig. 4. Fig. 4 is a diagram showing a cross-sectional structure of the imposition structure of the flexible substrate of this embodiment.

[0040] In step S20, The high-temperature resistant blue solder mask 120 is peeled off, and the lines 1110 are formed on the copper foil 110 of the flexible pressure-welded plate 20, and the copper layer 1330 is removed to form the flexible core substrate 30.

[0041] Furthermore, the step of forming flexible core substrate 30 includes fabricating voltage-resistant line 1120 and ground line 1130, and further includes fabricating line 1110 including normal line 1140, and after removing copper layer 1330, opening windows in adhesive layer 1320 and polyimide layer 1310 to form window opening portion 3110 of the core substrate, thereby forming flexible core substrate 30 as a whole.

[0042] In this embodiment, the flexible circuit board 60 is configured with the features of flexible characteristics, voltage-resistant lines 1120, and ground lines 1130 to form a flexible circuit board product that supports overall performance.

[0043] The window opening 3110 in the core substrate corresponds to the area where the subsequent conductive adhesive 620 will be silk-printed, and provides a passage for communication between the ground line 1130, the conductive adhesive 620, and the reinforcing material 610. Optionally, the distance by which one side of the window opening 3110 in the core substrate is shorter than the ground line 1130 is 20 μm to 125 μm, providing a reliable support for the ground line 1130.

[0044] Please continue to refer to Fig. 4, as well as Fig. 5 and Fig. 6. Fig. 5 is a diagram showing the cross-sectional structure of the pressure-welded plate of this embodiment, and Fig. 6 is a diagram showing the cross-sectional structure taken along line AA in Fig. 5.

[0045] In step S30, The first covering film and the second covering film are removed, and the first covering film, the flexible core substrate 30 and the second covering film are laminated in this order and pressed together to form the pressure-welded plate 50.

[0046] Furthermore, the step of forming the pressure-welded plate 50 includes the steps of: creating a first window opening 4130 in the first coating film corresponding to the voltage-resistant line 1120, and forming a first window-opening coating film 410 (including a first coating film polyimide layer 4110 and a first coating film adhesive layer 4120); creating a second window opening 4230 in the second coating film corresponding to the window opening 3110 of the core substrate, and forming a second window-opening coating film 420 (including a second coating film polyimide layer 4210 and a second coating film adhesive layer 4220); and sequentially stacking the first window-opening coating film 410, the flexible core substrate 30, and the second window-opening coating film 420 to form a flexible substrate laminate structure 40, orienting the line 1110 toward the first window-opening coating film 410 and pressing them together to form the pressure-welded plate 50.

[0047] The exposed pads or plug lines of the voltage-resistant lines 1120 need to have a first window opening 4130 made in the corresponding coating film, and then the corresponding ground lines 1130 of the conductive adhesive 620 need to be made, and the exposed pad positions need to have a second window opening 4230 made; Furthermore, since the line 1110 has already been fabricated and formed, the covering film cannot be made without adhesive, otherwise problems such as misalignment and breakage of the line 1110 may occur. However, the first covering film adhesive layer 4120 can provide good bonding strength for the pressure welding, and since there is no adhesive layer 1320 between the line 1110 and the polyimide layer 1310, after the pressure welding, a structure having the first covering film adhesive layer 4120 on only one side is formed. Testing the finished flexible circuit board 60 showed that its voltage resistance performance was significantly improved.

[0048] In addition, this embodiment further provides a second window coating film 420 on one side of the adhesive layer 1320, which can further effectively improve the voltage resistance characteristics (according to test comparisons on the finished product) while increasing the coverage of the plate body, thereby improving reliability.

[0049] Furthermore, one side of the second window opening 4230 is larger than the window opening 3110 of the core substrate, selectably by 50 μm to 150 μm.

[0050] The pressure-welded plate 50 is formed by pressing, and the window opening 3110 of the core substrate and the second window opening 4230 form a stepped window opening 510, which prevents the second window opening 4230 from shifting, warping, or expanding or shrinking due to errors after pressing. This blocks some of the window openings 3110 of the core substrate, while providing a larger adhesive body accommodating space when the conductive adhesive 620 is subsequently silk-screened, preventing problems such as cavities and trapped air bubbles when the conductive adhesive 620 is silk-screened.

[0051] Please refer to Fig. 7. Fig. 7 is a diagram showing the cross-sectional structure of the flexible circuit board of this embodiment.

[0052] In step S40, A reinforcing material 610 is attached to the pressure-welded plate 50 to form the flexible circuit board 60.

[0053] Furthermore, the step of forming the flexible circuit board 60 includes the step of silk-printing a conductive adhesive 620 on one surface of the second window-opening coating film 420 of the pressure-welded plate 50, and then attaching and pressing a reinforcing material 610 to form the flexible circuit board 60.

[0054] Optionally, the conductive adhesive 620 is epoxy resin conductive silver paste, epoxy resin conductive copper paste, acrylic conductive silver paste, or acrylic conductive copper paste. Optionally, after the adhesive layer is silk-printed, it is pre-baked, generally at a temperature of 65°C to 80°C for 5 minutes to 20 minutes, to achieve initial hardening of the adhesive body.

[0055] Furthermore, the stiffener 610 is a metallic stiffener, and can be selected from stainless steel, copper sheet, or aluminum sheet.

[0056] In this embodiment, a stiffener 610 is designed on the flexible circuit board 60, and the stiffener 610 is attached and bonded to the flexible circuit board 60 using a conductive adhesive 620. In particular, an effective network is formed that is connected to the ground line 1130 and is grounded via the stiffener 610. In practice, all flexible circuit boards with plug lines are generally designed with stiffeners to improve the strength of the plug lines. Generally, all stiffeners are fabricated using an adhesive layer. Therefore, in one embodiment, a plug line is designed on the flexible circuit board 60, and a stiffener 610 is provided in the plug line area. In this embodiment, instead of using the traditional insulating adhesive, a conductive adhesive 620 is used to attach the stiffener 610 and also to ensure the connection of the line 1110, thereby achieving a dual function.

[0057] Please refer to Figure 8. Figure 8 is a plan design diagram of the meshed line of this embodiment.

[0058] The ground line 1130 is fabricated as a mesh line 1130A, and the mesh line 1130A has a line width of 25 μm to 150 μm, and the gap between adjacent lines is 25 μm to 150 μm.

[0059] According to the design and test, when the size of the ground line 1130 is large and the size of the window opening 3110 of the core board is large, the conductive adhesive 620 contains metal powder particles, so the adhesive strength is slightly weaker than that of general adhesives. Therefore, after the conductive adhesive 620 is silk-printed, the area of ​​the metal copper surface may be large and the bonding strength may not be strong. In addition, during transportation and use, the flexible circuit board 60 may bend, vibrate, etc., so there may be a problem that the flexible circuit board 60 is not bonded firmly to the stiffener 610. This is likely to cause interaction forces, and furthermore, it is likely to cause problems such as the stiffness of the reinforcing material 610 not being strong enough. Therefore, by fabricating the ground line 1130 like the mesh-like line 1130A, and in particular fabricating the ground line 1130 within the range of the window opening 3110 of the core substrate like the mesh-like line 1130A, and exposing the adhesive layer 1320 at the position of the mesh holes, a good bonding effect can be achieved with the adhesive body in the conductive adhesive 620, and the bonding strength between the ground line 1130 and the reinforcing material 610 via the conductive adhesive 620 can be greatly improved.

[0060] Please refer to Fig. 9. Fig. 9 is a diagram showing the cross-sectional structure of another press-welded plate of this embodiment.

[0061] Furthermore, the side of the reinforcing material 610 facing the inside of the plate body of the flexible circuit board 60 is a corrugated side, that is, the reinforcing material 610 is a corrugated reinforcing material 610A.

[0062] Optionally, the waveform is a uniform arc-shaped wavy line, the height from the peak to the trough of the wave is 0.35 mm to 2.0 mm, and the length from one peak to another peak is 0.35 mm to 3.0 mm.

[0063] In this embodiment, the second aperture coating film 420 is increased to improve the withstand voltage characteristics, and the thickness of the entire plate is accordingly increased. When the flexible circuit board 60 is bent in use, the rear end of the stiffener 610 and the plate surface collide with each other, and the rubbing force is likely to cause the plate of the flexible circuit board 60 to tear from the rear end of the stiffener 610. Therefore, the corrugated stiffener 610A is used to reduce the resistance of the stiffener 610 to bending of the flexible circuit board 60 and improve the cushioning effect.

[0064] Please refer to Figures 10, 11 and 12. Figure 10 is a plan view of the corrugated reinforcement material of this embodiment, Figure 11 is a view showing the cross-sectional structure along the line BB in Figure 10, and Figure 12 is a view showing the cross-sectional structure of another flexible circuit board of this embodiment.

[0065] In one embodiment, the second coating film covers the area of ​​the voltage-resistant line 1120 .

[0066] After the attachment is completed, a partial covering film 420A is formed, another pressure-welding plate 50A is formed, and after a reinforcing material 610 is attached, another flexible circuit board 60A is formed.

[0067] When the plate size is large and the distribution pitch of the lines 1110 is large, the interference with the overall bending performance caused by the second coating film can be further reduced by selectively applying the coating film only to the area of ​​the voltage-resistant line 1120, thereby forming a processing method for partially applying the coating film, and effectively reducing the need for a window on the surface of the conductive adhesive 620 corresponding to the ground line 1130 (i.e., only the window 3110 of the core substrate exists, and the second window 4230 does not exist), making it easier to silk-print the conductive adhesive 620. For the adhesive layer 1320 that is not covered by the coating film, the part located in the area of ​​the stiffener 610 can be covered with the conductive adhesive 620, and the part located in other areas can be aged using a high-temperature baking method, optionally baked at 100°C to 150°C for 20 to 60 minutes.

[0068] In addition, circuit boards in the actual design and processing process are precise, and the actual structural diagrams and the sizes of interlayer thicknesses, line widths, etc. are all on the order of microns. For example, the thickness of each layer is generally 5 μm to 50 μm. If the drawings in the specification are prepared according to the actual proportions, there will be a problem that the illustrations will be unclear. Therefore, in order to more clearly show the process of realizing the manufacturing method, the drawings in this embodiment are all schematic diagrams that enlarge the technical features, and do not represent the size of the actual structural diagrams, nor do they represent enlarged views according to the same proportions of the actual structural diagrams.

[0069] The above is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the specification and drawings of the present invention based on the inventive idea of ​​the present invention, or anything directly or indirectly utilized in other related technical fields, are all included in the patent protection scope of the present invention.

[0070] (Addendum) (Appendix 1) A method for manufacturing a voltage-resistant flexible circuit board for a new energy vehicle, the method comprising: Step S10 includes taking a copper foil and a single-sided flexible copper-clad laminate having a structure in which a polyimide layer, an adhesive layer, and a copper layer are sequentially laminated, attaching a high-temperature resistant blue solder mask to one side of the copper foil to form a copper foil with a blue solder mask, performing a plasma activation process on the single-sided flexible copper-clad laminate, and then performing a chemical activation process to form an activated copper-clad laminate, laminating the copper foil with the blue solder mask and the activated copper-clad laminate, and pressing the copper foil against the polyimide layer to form a flexible pressure-welded plate; Step S20: peeling off the high-temperature resistant blue solder mask, forming a line on the copper foil of the flexible pressure-welded plate, and removing the copper layer to form a flexible core substrate; Step S30 of removing the first covering film and the second covering film, sequentially stacking the first covering film, the flexible core substrate, and the second covering film, and pressing them together to form a pressure-welded plate; and step S40 of attaching a reinforcing material to the pressure-welding plate to form the flexible circuit board.

[0071] (Appendix 2) 2. The method for manufacturing a voltage-resistant flexible circuit board for new energy vehicles according to claim 1, wherein the step of forming the flexible pressure-welded plate includes the steps of: laminating the copper foil and the activated copper-clad laminate to form a laminated structure; and providing a release film, a coverlay film, a release film, an aluminum sheet, and a release film on both sides of the laminated structure in that order to form a surface-mounted structure and then pressing the laminated structure together to form the flexible pressure-welded plate.

[0072] (Appendix 3) 3. The method for manufacturing a voltage-resistant flexible circuit board for new energy vehicles according to claim 1 or 2, wherein the step of forming the flexible core substrate comprises: fabricating the lines, including fabricating a voltage-resistant line and a ground line; and removing the copper layer, opening windows in the adhesive layer and the polyimide layer, forming window openings in the core substrate, and generally forming the flexible core substrate.

[0073] (Appendix 4) 4. The method for manufacturing a voltage-withstanding flexible circuit board for new energy vehicles according to claim 3, wherein the step of forming the pressure-welded plate includes the steps of: making a first window opening in the first coating film corresponding to the voltage-withstanding line, and forming a first window-opening coating film; making a second window opening in the second coating film corresponding to the window opening of the core substrate, and forming a second window-opening coating film; and sequentially stacking the first window-opening coating film, the flexible core substrate, and the second window-opening coating film, and pressing the lines toward the first window-opening coating film to form the pressure-welded plate.

[0074] (Appendix 5) The method for manufacturing a voltage-resistant flexible circuit board for new energy vehicles described in Appendix 4, characterized in that one side of the second window opening is larger than the window opening of the core substrate.

[0075] (Appendix 6) The step of forming the flexible circuit board includes: 6. The method for manufacturing a voltage-resistant flexible circuit board for new energy vehicles according to claim 4 or 5, comprising the steps of silk-printing a conductive adhesive on one surface of the second window-opening coating film of the pressure-welded plate, and then attaching and pressing the reinforcing material to form the flexible circuit board.

[0076] (Appendix 7) The method for manufacturing a voltage-resistant flexible circuit board for new energy vehicles described in Appendix 6, characterized in that the reinforcing material is a metallic reinforcing material.

[0077] (Appendix 8) The method for manufacturing a voltage-resistant flexible circuit board for new energy vehicles described in Appendix 4, characterized in that the second coating film covers the area of ​​the voltage-resistant line.

[0078] (Appendix 9) The method for manufacturing a voltage-resistant flexible circuit board for new energy vehicles described in Appendix 1, characterized in that the reinforcing material has a corrugated edge facing toward the inside of the plate body of the flexible circuit board. [Explanation of symbols]

[0079] 10...implantation structure, 10A...laminate structure, 110...copper foil, 120...high temperature resistant blue solder mask, 1020...copper foil with blue solder mask, 130...activated copper clad laminate, 1310...polyimide layer, 1320...adhesive layer, 1330...copper layer, 1410...first release film, 1420...second release film, 1430...third release film, 1440...fourth release film, 1450...fifth release film, 1460...sixth release film, 1510...first coverlay film, 1520...second coverlay film, 1610...first aluminum sheet, 1620...second aluminum sheet, 1710...upper table of press, 1720...lower table of press, 20...flexible pressure plate, 30...flexible Flexible core substrate, 1110...line, 1120...voltage-resistant line, 1130...ground line, 1140...normal line, 3110...window opening of core substrate, 40...flexible substrate laminate structure, 410...first window opening coating film, 4110...first coating film polyimide layer, 4120...first coating film adhesive layer, 4130...first window opening, 420...second window opening coating film, 421 0...second coating film polyimide layer, 4220...second coating film adhesive layer, 4230...second window opening, 50...pressure plate, 510...stepped window opening, 60...flexible circuit board, 610...reinforcement material, 620...conductive adhesive, 50A...another pressure plate, 420A...partial coating film, 60A...another flexible circuit board, 1130A...mesh-like line, 610A...corrugated reinforcement material.

Claims

1. A method for manufacturing a voltage-resistant flexible circuit board for a new energy vehicle, the method comprising: Step S10 includes taking a copper foil and a single-sided flexible copper-clad laminate having a structure in which a polyimide layer, an adhesive layer, and a copper layer are sequentially laminated, attaching a high-temperature resistant blue solder mask to one side of the copper foil to form a copper foil with a blue solder mask, performing a plasma activation process on the single-sided flexible copper-clad laminate, and then performing a chemical activation process to form an activated copper-clad laminate, laminating the copper foil with the blue solder mask and the activated copper-clad laminate, and pressing the copper foil against the polyimide layer to form a flexible pressure-welded plate; Step S20: peeling off the high-temperature resistant blue solder mask, forming a line on the copper foil of the flexible pressure-welded plate, and removing the copper layer to form a flexible core substrate; Step S30 of removing the first covering film and the second covering film, sequentially stacking the first covering film, the flexible core substrate, and the second covering film, and pressing them together to form a pressure-welded plate; and step S40 of attaching a reinforcing material to the pressure-welding plate to form the flexible circuit board.

2. 2. The method for manufacturing a voltage-resistant flexible circuit board for new energy vehicles according to claim 1, wherein the step of forming the flexible pressure-welded plate includes the steps of: laminating the copper foil and the activated copper-clad laminate to form a laminated structure; and providing a release film, a coverlay film, a release film, an aluminum sheet, and a release film on both sides of the laminated structure in that order to form a surface-mounted structure and then pressing them together to form the flexible pressure-welded plate.

3. 3. The method for manufacturing a voltage-withstanding flexible circuit board for new energy vehicles according to claim 1, wherein the step of forming the flexible core substrate comprises: fabricating the lines, including fabricating a voltage-withstanding line and a ground line; and removing the copper layer, opening windows in the adhesive layer and the polyimide layer to form window openings in the core substrate, and overall forming the flexible core substrate.

4. 4. The method for manufacturing a voltage-withstanding flexible circuit board for new energy vehicles according to claim 3, wherein the step of forming the pressure-welded plate includes the steps of: making a first window opening in the first coating film corresponding to the voltage-withstanding line, thereby forming a first window-opening coating film; making a second window opening in the second coating film corresponding to the window opening of the core substrate, thereby forming a second window-opening coating film; and sequentially stacking the first window-opening coating film, the flexible core substrate, and the second window-opening coating film, with the line facing the first window-opening coating film, and pressing them together to form the pressure-welded plate.

5. 5. The method for manufacturing a voltage-resistant flexible circuit board for new energy vehicles according to claim 4, wherein one side of the second window opening is larger than the window opening of the core substrate.

6. The step of forming the flexible circuit board includes:

5. The method for manufacturing a voltage-resistant flexible circuit board for new energy vehicles according to claim 4, further comprising the steps of: silk-printing a conductive adhesive on one surface of the second window-opening coating film of the pressure-welding plate; and then attaching and pressing the reinforcing material to form the flexible circuit board.

7. 7. The method for manufacturing a voltage-resistant flexible circuit board for new energy vehicles according to claim 6, wherein the reinforcing material is a metallic reinforcing material.

8. 5. The method for manufacturing a voltage-resistant flexible circuit board for new energy vehicles according to claim 4, wherein the second coating film covers the area of ​​the voltage-resistant line.

9. 2. The method for manufacturing a voltage-resistant flexible circuit board for new energy vehicles according to claim 1, wherein the reinforcing material has a corrugated edge facing the inside of the plate body of the flexible circuit board.

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